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xnu-2782.1.97.tar.gz
[apple/xnu.git] / bsd / dev / dtrace / dtrace.c
index bdbe6a8746acf34b8caf87bd2286425b469227c7..25f6d7c8e4d5156f6da257955b7a8bc80540eae0 100644 (file)
  */
 
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Portions copyright (c) 2011, Joyent, Inc. All rights reserved.
+ */
+
+/*
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-/* #pragma ident       "@(#)dtrace.c   1.49    06/08/11 SMI" */
+/* #pragma ident       "@(#)dtrace.c   1.65    08/07/02 SMI" */
 
 /*
  * DTrace - Dynamic Tracing for Solaris
@@ -65,9 +69,6 @@
  * [Group] Functions", allowing one to find each block by searching forward
  * on capital-f functions.
  */
-
-#define _DTRACE_WANT_PROC_GLUE_        1
-
 #include <sys/errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -75,6 +76,7 @@
 #include <sys/systm.h>
 #include <sys/dtrace_impl.h>
 #include <sys/param.h>
+#include <sys/proc_internal.h>
 #include <sys/ioctl.h>
 #include <sys/fcntl.h>
 #include <miscfs/devfs/devfs.h>
 #include <sys/user.h>
 #include <mach/exception_types.h>
 #include <sys/signalvar.h>
+#include <mach/task.h>
 #include <kern/zalloc.h>
+#include <kern/ast.h>
+#include <kern/task.h>
+#include <netinet/in.h>
+
+#include <kern/cpu_data.h>
+extern uint32_t pmap_find_phys(void *, uint64_t);
+extern boolean_t pmap_valid_page(uint32_t);
+extern void OSKextRegisterKextsWithDTrace(void);
+extern kmod_info_t g_kernel_kmod_info;
+
+/* Solaris proc_t is the struct. Darwin's proc_t is a pointer to it. */
+#define proc_t struct proc /* Steer clear of the Darwin typedef for proc_t */
 
 #define t_predcache t_dtrace_predcache /* Cosmetic. Helps readability of thread.h */
 
@@ -95,23 +110,26 @@ extern void dtrace_suspend(void);
 extern void dtrace_resume(void);
 extern void dtrace_init(void);
 extern void helper_init(void);
-
-#if defined(__APPLE__)
+extern void fasttrap_init(void);
+extern void dtrace_lazy_dofs_duplicate(proc_t *, proc_t *);
+extern void dtrace_lazy_dofs_destroy(proc_t *);
+extern void dtrace_postinit(void);
 
 #include "../../../osfmk/chud/chud_dtrace.h"
 
 extern kern_return_t chudxnu_dtrace_callback
        (uint64_t selector, uint64_t *args, uint32_t count);
-#endif
+
+/* Import this function to retrieve the physical memory. */
+extern int kernel_sysctlbyname(const char *name, void *oldp,
+       size_t *oldlenp, void *newp, size_t newlen);
 
 /*
  * DTrace Tunable Variables
  *
- * The following variables may be tuned by adding a line to /etc/system that
- * includes both the name of the DTrace module ("dtrace") and the name of the
- * variable.  For example:
- *
- *   set dtrace:dtrace_destructive_disallow = 1
+ * The following variables may be dynamically tuned by using sysctl(8), the
+ * variables being stored in the kern.dtrace namespace.  For example:
+ *     sysctl kern.dtrace.dof_maxsize = 1048575        # 1M
  *
  * In general, the only variables that one should be tuning this way are those
  * that affect system-wide DTrace behavior, and for which the default behavior
@@ -120,26 +138,23 @@ extern kern_return_t chudxnu_dtrace_callback
  * When tuning these variables, avoid pathological values; while some attempt
  * is made to verify the integrity of these variables, they are not considered
  * part of the supported interface to DTrace, and they are therefore not
- * checked comprehensively.  Further, these variables should not be tuned
- * dynamically via "mdb -kw" or other means; they should only be tuned via
- * /etc/system.
+ * checked comprehensively.
  */
+uint64_t       dtrace_buffer_memory_maxsize = 0;               /* initialized in dtrace_init */
+uint64_t       dtrace_buffer_memory_inuse = 0;
 int            dtrace_destructive_disallow = 0;
-#if defined(__APPLE__)
-#define proc_t struct proc
-#endif /* __APPLE__ */
 dtrace_optval_t        dtrace_nonroot_maxsize = (16 * 1024 * 1024);
 size_t         dtrace_difo_maxsize = (256 * 1024);
-dtrace_optval_t        dtrace_dof_maxsize = (256 * 1024);
+dtrace_optval_t        dtrace_dof_maxsize = (384 * 1024);
 size_t         dtrace_global_maxsize = (16 * 1024);
 size_t         dtrace_actions_max = (16 * 1024);
 size_t         dtrace_retain_max = 1024;
 dtrace_optval_t        dtrace_helper_actions_max = 32;
-dtrace_optval_t        dtrace_helper_providers_max = 32;
+dtrace_optval_t        dtrace_helper_providers_max = 64;
 dtrace_optval_t        dtrace_dstate_defsize = (1 * 1024 * 1024);
 size_t         dtrace_strsize_default = 256;
-dtrace_optval_t        dtrace_cleanrate_default = 9900990;             /* 101 hz */
-dtrace_optval_t        dtrace_cleanrate_min = 200000;                  /* 5000 hz */
+dtrace_optval_t        dtrace_cleanrate_default = 990099000;           /* 1.1 hz */
+dtrace_optval_t        dtrace_cleanrate_min = 20000000;                        /* 50 hz */
 dtrace_optval_t        dtrace_cleanrate_max = (uint64_t)60 * NANOSEC;  /* 1/minute */
 dtrace_optval_t        dtrace_aggrate_default = NANOSEC;               /* 1 hz */
 dtrace_optval_t        dtrace_statusrate_default = NANOSEC;            /* 1 hz */
@@ -156,6 +171,7 @@ hrtime_t    dtrace_chill_max = 500 * (NANOSEC / MILLISEC);  /* 500 ms */
 hrtime_t       dtrace_chill_interval = NANOSEC;                /* 1000 ms */
 int            dtrace_devdepth_max = 32;
 int            dtrace_err_verbose;
+int            dtrace_provide_private_probes = 0;
 hrtime_t       dtrace_deadman_interval = NANOSEC;
 hrtime_t       dtrace_deadman_timeout = (hrtime_t)10 * NANOSEC;
 hrtime_t       dtrace_deadman_user = (hrtime_t)30 * NANOSEC;
@@ -170,7 +186,7 @@ hrtime_t    dtrace_deadman_user = (hrtime_t)30 * NANOSEC;
  * it is used by some translators as an implementation detail.
  */
 const char     dtrace_zero[256] = { 0 };       /* zero-filled memory */
-
+unsigned int   dtrace_max_cpus = 0;            /* number of enabled cpus */
 /*
  * DTrace Internal Variables
  */
@@ -199,23 +215,28 @@ static dtrace_ecb_t       *dtrace_ecb_create_cache; /* cached created ECB */
 static dtrace_genid_t  dtrace_probegen;        /* current probe generation */
 static dtrace_helpers_t *dtrace_deferred_pid;  /* deferred helper list */
 static dtrace_enabling_t *dtrace_retained;     /* list of retained enablings */
+static dtrace_genid_t   dtrace_retained_gen;    /* current retained enab gen */
 static dtrace_dynvar_t dtrace_dynhash_sink;    /* end of dynamic hash chains */
-#if defined(__APPLE__)
-static int             dtrace_dof_mode;        /* dof mode */
-#endif
 
-#if defined(__APPLE__)
+static int             dtrace_dof_mode;        /* See dtrace_impl.h for a description of Darwin's dof modes. */
+
+                       /*
+                        * This does't quite fit as an internal variable, as it must be accessed in
+                        * fbt_provide and sdt_provide. Its clearly not a dtrace tunable variable either...
+                        */
+int                    dtrace_kernel_symbol_mode;      /* See dtrace_impl.h for a description of Darwin's kernel symbol modes. */
+
 
 /*
  * To save memory, some common memory allocations are given a
- * unique zone. In example, dtrace_probe_t is 72 bytes in size,
+ * unique zone. For example, dtrace_probe_t is 72 bytes in size,
  * which means it would fall into the kalloc.128 bucket. With
  * 20k elements allocated, the space saved is substantial.
  */
 
 struct zone *dtrace_probe_t_zone;
 
-#endif
+static int dtrace_module_unloaded(struct kmod_info *kmod);
 
 /*
  * DTrace Locking
@@ -248,12 +269,14 @@ struct zone *dtrace_probe_t_zone;
  * acquired _between_ dtrace_provider_lock and dtrace_lock.
  */
 
+
 /*
  * APPLE NOTE:
  *
- * All kmutex_t vars have been changed to lck_mtx_t.
- * Note that lck_mtx_t's require explicit initialization.
+ * For porting purposes, all kmutex_t vars have been changed
+ * to lck_mtx_t, which require explicit initialization.
  *
+ * kmutex_t becomes lck_mtx_t
  * mutex_enter() becomes lck_mtx_lock()
  * mutex_exit() becomes lck_mtx_unlock()
  *
@@ -263,14 +286,11 @@ struct zone *dtrace_probe_t_zone;
  *     becomes:
  * lck_mtx_assert(&cpu_lock, LCK_MTX_ASSERT_OWNED);
  *
- * Due to the number of these changes, they are not called out explicitly.
  */
 static lck_mtx_t       dtrace_lock;            /* probe state lock */
 static lck_mtx_t       dtrace_provider_lock;   /* provider state lock */
 static lck_mtx_t       dtrace_meta_lock;       /* meta-provider state lock */
-#if defined(__APPLE__)
 static lck_rw_t                dtrace_dof_mode_lock;   /* dof mode lock */
-#endif
 
 /*
  * DTrace Provider Variables
@@ -290,10 +310,16 @@ static void
 dtrace_nullop(void)
 {}
 
+static int
+dtrace_enable_nullop(void)
+{
+    return (0);
+}
+
 static dtrace_pops_t   dtrace_provider_ops = {
        (void (*)(void *, const dtrace_probedesc_t *))dtrace_nullop,
        (void (*)(void *, struct modctl *))dtrace_nullop,
-       (void (*)(void *, dtrace_id_t, void *))dtrace_nullop,
+       (int (*)(void *, dtrace_id_t, void *))dtrace_enable_nullop,
        (void (*)(void *, dtrace_id_t, void *))dtrace_nullop,
        (void (*)(void *, dtrace_id_t, void *))dtrace_nullop,
        (void (*)(void *, dtrace_id_t, void *))dtrace_nullop,
@@ -313,14 +339,15 @@ dtrace_id_t               dtrace_probeid_error;   /* special ERROR probe */
 uint32_t dtrace_helptrace_next = 0;
 uint32_t dtrace_helptrace_nlocals;
 char   *dtrace_helptrace_buffer;
-int    dtrace_helptrace_bufsize = 512 * 1024;
+size_t dtrace_helptrace_bufsize = 512 * 1024;
 
-#ifdef DEBUG
+#if DEBUG
 int    dtrace_helptrace_enabled = 1;
 #else
 int    dtrace_helptrace_enabled = 0;
 #endif
 
+
 /*
  * DTrace Error Hashing
  *
@@ -330,7 +357,7 @@ int dtrace_helptrace_enabled = 0;
  * debugging problems in the DIF code generator or in DOF generation .  The
  * error hash may be examined with the ::dtrace_errhash MDB dcmd.
  */
-#ifdef DEBUG
+#if DEBUG
 static dtrace_errhash_t        dtrace_errhash[DTRACE_ERRHASHSZ];
 static const char *dtrace_errlast;
 static kthread_t *dtrace_errthread;
@@ -360,9 +387,11 @@ static lck_mtx_t dtrace_errlock;
 
 #define        DTRACE_AGGHASHSIZE_SLEW         17
 
+#define        DTRACE_V4MAPPED_OFFSET          (sizeof (uint32_t) * 3)
+
 /*
  * The key for a thread-local variable consists of the lower 61 bits of the
- * t_did, plus the 3 bits of the highest active interrupt above LOCK_LEVEL.
+ * current_thread(), plus the 3 bits of the highest active interrupt above LOCK_LEVEL.
  * We add DIF_VARIABLE_MAX to t_did to assure that the thread key is never
  * equal to a variable identifier.  This is necessary (but not sufficient) to
  * assure that global associative arrays never collide with thread-local
@@ -375,79 +404,30 @@ static lck_mtx_t dtrace_errlock;
  * no way for a global variable key signature to match a thread-local key
  * signature.
  */
-#if !defined(__APPLE__)
+#if defined (__x86_64__)
+/* FIXME: two function calls!! */
 #define        DTRACE_TLS_THRKEY(where) { \
-       uint_t intr = 0; \
-       uint_t actv = CPU->cpu_intr_actv >> (LOCK_LEVEL + 1); \
-       for (; actv; actv >>= 1) \
-               intr++; \
+       uint_t intr = ml_at_interrupt_context(); /* Note: just one measly bit */ \
+       uint64_t thr = (uintptr_t)current_thread(); \
        ASSERT(intr < (1 << 3)); \
-       (where) = ((curthread->t_did + DIF_VARIABLE_MAX) & \
+       (where) = ((thr + DIF_VARIABLE_MAX) & \
            (((uint64_t)1 << 61) - 1)) | ((uint64_t)intr << 61); \
 }
 #else
-#define        DTRACE_TLS_THRKEY(where) { \
-       uint_t intr = ml_at_interrupt_context(); /* XXX just one measely bit */ \
-       uint_t thr = (uint_t)current_thread(); \
-       uint_t pid = (uint_t)proc_selfpid(); \
-       ASSERT(intr < (1 << 3)); \
-       (where) = ((((uint64_t)thr << 32 | pid) + DIF_VARIABLE_MAX) & \
-           (((uint64_t)1 << 61) - 1)) | ((uint64_t)intr << 61); \
-}
-#endif /* __APPLE__ */
+#error Unknown architecture
+#endif
+
+#define        DT_BSWAP_8(x)   ((x) & 0xff)
+#define        DT_BSWAP_16(x)  ((DT_BSWAP_8(x) << 8) | DT_BSWAP_8((x) >> 8))
+#define        DT_BSWAP_32(x)  ((DT_BSWAP_16(x) << 16) | DT_BSWAP_16((x) >> 16))
+#define        DT_BSWAP_64(x)  ((DT_BSWAP_32(x) << 32) | DT_BSWAP_32((x) >> 32))
+
+#define        DT_MASK_LO 0x00000000FFFFFFFFULL
 
 #define        DTRACE_STORE(type, tomax, offset, what) \
        *((type *)((uintptr_t)(tomax) + (uintptr_t)offset)) = (type)(what);
 
-#if !defined(__APPLE__)
-#if !(defined(__i386__) || defined (__x86_64__))
-#define        DTRACE_ALIGNCHECK(addr, size, flags)                            \
-       if (addr & (size - 1)) {                                        \
-               *flags |= CPU_DTRACE_BADALIGN;                          \
-               cpu_core[CPU->cpu_id].cpuc_dtrace_illval = addr;        \
-               return (0);                                             \
-       }
-#else
-#define        DTRACE_ALIGNCHECK(addr, size, flags)
-#endif
 
-#define        DTRACE_LOADFUNC(bits)                                           \
-/*CSTYLED*/                                                            \
-uint##bits##_t                                                         \
-dtrace_load##bits(uintptr_t addr)                                      \
-{                                                                      \
-       size_t size = bits / NBBY;                                      \
-       /*CSTYLED*/                                                     \
-       uint##bits##_t rval;                                            \
-       int i;                                                          \
-       volatile uint16_t *flags = (volatile uint16_t *)                \
-           &cpu_core[CPU->cpu_id].cpuc_dtrace_flags;                   \
-                                                                       \
-       DTRACE_ALIGNCHECK(addr, size, flags);                           \
-                                                                       \
-       for (i = 0; i < dtrace_toxranges; i++) {                        \
-               if (addr >= dtrace_toxrange[i].dtt_limit)               \
-                       continue;                                       \
-                                                                       \
-               if (addr + size <= dtrace_toxrange[i].dtt_base)         \
-                       continue;                                       \
-                                                                       \
-               /*                                                      \
-                * This address falls within a toxic region; return 0.  \
-                */                                                     \
-               *flags |= CPU_DTRACE_BADADDR;                           \
-               cpu_core[CPU->cpu_id].cpuc_dtrace_illval = addr;        \
-               return (0);                                             \
-       }                                                               \
-                                                                       \
-       *flags |= CPU_DTRACE_NOFAULT;                                   \
-       /*CSTYLED*/                                                     \
-       rval = *((volatile uint##bits##_t *)addr);                      \
-       *flags &= ~CPU_DTRACE_NOFAULT;                                  \
-                                                                       \
-       return (rval);                                                  \
-}
-#else
 #define        DTRACE_ALIGNCHECK(addr, size, flags)                            \
        if (addr & (MIN(size,4) - 1)) {                                 \
                *flags |= CPU_DTRACE_BADALIGN;                          \
@@ -455,11 +435,33 @@ dtrace_load##bits(uintptr_t addr)                                 \
                return (0);                                             \
        }
 
-#define RECOVER_LABEL(bits) __asm__ volatile("_dtraceLoadRecover" #bits ":" );
+/*
+ * Test whether a range of memory starting at testaddr of size testsz falls
+ * within the range of memory described by addr, sz.  We take care to avoid
+ * problems with overflow and underflow of the unsigned quantities, and
+ * disallow all negative sizes.  Ranges of size 0 are allowed.
+ */
+#define        DTRACE_INRANGE(testaddr, testsz, baseaddr, basesz) \
+       ((testaddr) - (baseaddr) < (basesz) && \
+       (testaddr) + (testsz) - (baseaddr) <= (basesz) && \
+       (testaddr) + (testsz) >= (testaddr))
+
+/*
+ * Test whether alloc_sz bytes will fit in the scratch region.  We isolate
+ * alloc_sz on the righthand side of the comparison in order to avoid overflow
+ * or underflow in the comparison with it.  This is simpler than the INRANGE
+ * check above, because we know that the dtms_scratch_ptr is valid in the
+ * range.  Allocations of size zero are allowed.
+ */
+#define        DTRACE_INSCRATCH(mstate, alloc_sz) \
+       ((mstate)->dtms_scratch_base + (mstate)->dtms_scratch_size - \
+       (mstate)->dtms_scratch_ptr >= (alloc_sz))
 
+#define RECOVER_LABEL(bits) dtraceLoadRecover##bits:
+
+#if defined (__x86_64__)
 #define        DTRACE_LOADFUNC(bits)                                           \
 /*CSTYLED*/                                                            \
-extern vm_offset_t dtraceLoadRecover##bits;                            \
 uint##bits##_t dtrace_load##bits(uintptr_t addr);                      \
                                                                        \
 uint##bits##_t                                                         \
@@ -469,7 +471,6 @@ dtrace_load##bits(uintptr_t addr)                                   \
        /*CSTYLED*/                                                     \
        uint##bits##_t rval = 0;                                        \
        int i;                                                          \
-       ppnum_t pp;                                                     \
        volatile uint16_t *flags = (volatile uint16_t *)                \
            &cpu_core[CPU->cpu_id].cpuc_dtrace_flags;                   \
                                                                        \
@@ -490,21 +491,17 @@ dtrace_load##bits(uintptr_t addr)                                 \
                return (0);                                             \
        }                                                               \
                                                                        \
-       pp = pmap_find_phys(kernel_pmap, addr);                         \
-                                                                       \
-       if (0 == pp || /* pmap_find_phys failed ? */                    \
-           !dtxnu_is_RAM_page(pp) /* Backed by RAM? */ ) {             \
-               *flags |= CPU_DTRACE_BADADDR;                           \
-               cpu_core[CPU->cpu_id].cpuc_dtrace_illval = addr;        \
-               return (0);                                             \
-       }                                                               \
-                                                                       \
        {                                                               \
-       volatile vm_offset_t recover = (vm_offset_t)&dtraceLoadRecover##bits;           \
+       volatile vm_offset_t recover = (vm_offset_t)&&dtraceLoadRecover##bits;          \
        *flags |= CPU_DTRACE_NOFAULT;                                   \
        recover = dtrace_set_thread_recover(current_thread(), recover); \
        /*CSTYLED*/                                                     \
-       rval = *((volatile uint##bits##_t *)addr);                      \
+       /*                                                              \
+       * PR6394061 - avoid device memory that is unpredictably         \
+       * mapped and unmapped                                           \
+       */                                                              \
+        if (pmap_valid_page(pmap_find_phys(kernel_pmap, addr)))                \
+           rval = *((volatile uint##bits##_t *)addr);                  \
        RECOVER_LABEL(bits);                                            \
        (void)dtrace_set_thread_recover(current_thread(), recover);     \
        *flags &= ~CPU_DTRACE_NOFAULT;                                  \
@@ -512,8 +509,9 @@ dtrace_load##bits(uintptr_t addr)                                   \
                                                                        \
        return (rval);                                                  \
 }
-#endif /* __APPLE__ */
-
+#else /* all other architectures */
+#error Unknown Architecture
+#endif
 
 #ifdef __LP64__
 #define        dtrace_loadptr  dtrace_load64
@@ -525,6 +523,7 @@ dtrace_load##bits(uintptr_t addr)                                   \
 #define        DTRACE_DYNHASH_SINK     1
 #define        DTRACE_DYNHASH_VALID    2
 
+#define DTRACE_MATCH_FAIL       -1
 #define        DTRACE_MATCH_NEXT       0
 #define        DTRACE_MATCH_DONE       1
 #define        DTRACE_ANCHORED(probe)  ((probe)->dtpr_func[0] != '\0')
@@ -539,12 +538,15 @@ dtrace_load##bits(uintptr_t addr)                                 \
        ((flags) & CPU_DTRACE_TUPOFLOW) ?  DTRACEFLT_TUPOFLOW :         \
        ((flags) & CPU_DTRACE_BADALIGN) ?  DTRACEFLT_BADALIGN :         \
        ((flags) & CPU_DTRACE_NOSCRATCH) ?  DTRACEFLT_NOSCRATCH :       \
+       ((flags) & CPU_DTRACE_BADSTACK) ?  DTRACEFLT_BADSTACK :         \
        DTRACEFLT_UNKNOWN)
 
 #define        DTRACEACT_ISSTRING(act)                                         \
        ((act)->dta_kind == DTRACEACT_DIFEXPR &&                        \
        (act)->dta_difo->dtdo_rtype.dtdt_kind == DIF_TYPE_STRING)
 
+
+static size_t dtrace_strlen(const char *, size_t);
 static dtrace_probe_t *dtrace_probe_lookup_id(dtrace_id_t id);
 static void dtrace_enabling_provide(dtrace_provider_t *);
 static int dtrace_enabling_match(dtrace_enabling_t *, int *);
@@ -561,6 +563,225 @@ static int dtrace_state_option(dtrace_state_t *, dtrace_optid_t,
 static int dtrace_ecb_create_enable(dtrace_probe_t *, void *);
 static void dtrace_helper_provider_destroy(dtrace_helper_provider_t *);
 
+
+/*
+ * DTrace sysctl handlers
+ *
+ * These declarations and functions are used for a deeper DTrace configuration.
+ * Most of them are not per-consumer basis and may impact the other DTrace
+ * consumers.  Correctness may not be supported for all the variables, so you
+ * should be careful about what values you are using.
+ */
+
+SYSCTL_DECL(_kern_dtrace);
+SYSCTL_NODE(_kern, OID_AUTO, dtrace, CTLFLAG_RW | CTLFLAG_LOCKED, 0, "dtrace"); 
+
+static int
+sysctl_dtrace_err_verbose SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg2)
+       int changed, error;
+       int value = *(int *) arg1;
+
+       error = sysctl_io_number(req, value, sizeof(value), &value, &changed);
+       if (error || !changed)
+               return (error);
+
+       if (value != 0 && value != 1)
+               return (ERANGE);
+
+       lck_mtx_lock(&dtrace_lock);
+               dtrace_err_verbose = value;
+       lck_mtx_unlock(&dtrace_lock);
+
+       return (0);
+}
+
+/*
+ * kern.dtrace.err_verbose
+ *
+ * Set DTrace verbosity when an error occured (0 = disabled, 1 = enabld).
+ * Errors are reported when a DIFO or a DOF has been rejected by the kernel.
+ */
+SYSCTL_PROC(_kern_dtrace, OID_AUTO, err_verbose,
+       CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+       &dtrace_err_verbose, 0,
+       sysctl_dtrace_err_verbose, "I", "dtrace error verbose");
+
+static int
+sysctl_dtrace_buffer_memory_maxsize SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg2, req)
+       int changed, error;
+       uint64_t value = *(uint64_t *) arg1;
+
+       error = sysctl_io_number(req, value, sizeof(value), &value, &changed);
+       if (error || !changed)
+               return (error);
+
+       if (value <= dtrace_buffer_memory_inuse)
+               return (ERANGE);
+
+       lck_mtx_lock(&dtrace_lock);
+               dtrace_buffer_memory_maxsize = value;   
+       lck_mtx_unlock(&dtrace_lock);
+
+       return (0);
+}
+
+/*
+ * kern.dtrace.buffer_memory_maxsize
+ *
+ * Set DTrace maximal size in bytes used by all the consumers' state buffers.  By default
+ * the limit is PHYS_MEM / 3 for *all* consumers.  Attempting to set a null, a negative value
+ * or a value <= to dtrace_buffer_memory_inuse will result in a failure.
+ */
+SYSCTL_PROC(_kern_dtrace, OID_AUTO, buffer_memory_maxsize,
+       CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
+       &dtrace_buffer_memory_maxsize, 0,
+       sysctl_dtrace_buffer_memory_maxsize, "Q", "dtrace state buffer memory maxsize");
+
+/*
+ * kern.dtrace.buffer_memory_inuse
+ *
+ * Current state buffer memory used, in bytes, by all the DTrace consumers.
+ * This value is read-only.
+ */
+SYSCTL_QUAD(_kern_dtrace, OID_AUTO, buffer_memory_inuse, CTLFLAG_RD | CTLFLAG_LOCKED,
+       &dtrace_buffer_memory_inuse, "dtrace state buffer memory in-use");
+
+static int
+sysctl_dtrace_difo_maxsize SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg2, req)
+       int changed, error;
+       size_t value = *(size_t*) arg1;
+
+       error = sysctl_io_number(req, value, sizeof(value), &value, &changed);
+       if (error || !changed)
+               return (error);
+
+       if (value <= 0)
+               return (ERANGE);
+
+       lck_mtx_lock(&dtrace_lock);
+               dtrace_difo_maxsize = value;
+       lck_mtx_unlock(&dtrace_lock);
+
+       return (0);
+}
+
+/*
+ * kern.dtrace.difo_maxsize
+ *
+ * Set the DIFO max size in bytes, check the definition of dtrace_difo_maxsize
+ * to get the default value.  Attempting to set a null or negative size will
+ * result in a failure.
+ */
+SYSCTL_PROC(_kern_dtrace, OID_AUTO, difo_maxsize,
+       CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
+       &dtrace_difo_maxsize, 0,
+       sysctl_dtrace_difo_maxsize, "Q", "dtrace difo maxsize");
+
+static int
+sysctl_dtrace_dof_maxsize SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg2, req)
+       int changed, error;
+       dtrace_optval_t value = *(dtrace_optval_t *) arg1;
+
+       error = sysctl_io_number(req, value, sizeof(value), &value, &changed);
+       if (error || !changed)
+               return (error);
+
+       if (value <= 0)
+               return (ERANGE);
+
+       lck_mtx_lock(&dtrace_lock);
+               dtrace_dof_maxsize = value;
+       lck_mtx_unlock(&dtrace_lock);
+
+       return (0);
+}
+
+/*
+ * kern.dtrace.dof_maxsize
+ *
+ * Set the DOF max size in bytes, check the definition of dtrace_dof_maxsize to
+ * get the default value.  Attempting to set a null or negative size will result
+ * in a failure.
+ */
+SYSCTL_PROC(_kern_dtrace, OID_AUTO, dof_maxsize,
+       CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
+       &dtrace_dof_maxsize, 0,
+       sysctl_dtrace_dof_maxsize, "Q", "dtrace dof maxsize");
+
+static int
+sysctl_dtrace_global_maxsize SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg2, req)
+       int changed, error;
+       dtrace_optval_t value = *(dtrace_optval_t*) arg1;
+
+       error = sysctl_io_number(req, value, sizeof(value), &value, &changed);
+       if (error || !changed)
+               return (error);
+
+       if (value <= 0)
+               return (ERANGE);
+
+       lck_mtx_lock(&dtrace_lock);
+               dtrace_global_maxsize = value;
+       lck_mtx_unlock(&dtrace_lock);
+
+       return (0);
+}
+
+/*
+ * kern.dtrace.global_maxsize
+ *
+ * Set the global variable max size in bytes, check the definition of
+ * dtrace_global_maxsize to get the default value.  Attempting to set a null or
+ * negative size will result in a failure.
+ */
+SYSCTL_PROC(_kern_dtrace, OID_AUTO, global_maxsize,
+       CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
+       &dtrace_global_maxsize, 0,
+       sysctl_dtrace_global_maxsize, "Q", "dtrace global maxsize");
+
+static int
+sysctl_dtrace_provide_private_probes SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg2)
+       int error;
+       int value = *(int *) arg1;
+
+       error = sysctl_io_number(req, value, sizeof(value), &value, NULL);
+       if (error)
+               return (error);
+
+       if (value != 0 && value != 1)
+               return (ERANGE);
+
+       lck_mtx_lock(&dtrace_lock);
+               dtrace_provide_private_probes = value;
+       lck_mtx_unlock(&dtrace_lock);
+
+       return (0);
+}
+
+/*
+ * kern.dtrace.provide_private_probes
+ *
+ * Set whether the providers must provide the private probes.  This is
+ * mainly used by the FBT provider to request probes for the private/static
+ * symbols.
+ */
+SYSCTL_PROC(_kern_dtrace, OID_AUTO, provide_private_probes,
+       CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+       &dtrace_provide_private_probes, 0,
+       sysctl_dtrace_provide_private_probes, "I", "provider must provide the private probes");
+
 /*
  * DTrace Probe Context Functions
  *
@@ -578,20 +799,11 @@ static void dtrace_helper_provider_destroy(dtrace_helper_provider_t *);
  * for these functions, there will be a comment above the function reading
  * "Note:  not called from probe context."
  */
-void
-dtrace_panic(const char *format, ...)
-{
-       va_list alist;
-
-       va_start(alist, format);
-       dtrace_vpanic(format, alist);
-       va_end(alist);
-}
 
 int
 dtrace_assfail(const char *a, const char *f, int l)
 {
-       dtrace_panic("assertion failed: %s, file: %s, line: %d", a, f, l);
+       panic("dtrace: assertion failed: %s, file: %s, line: %d", a, f, l);
 
        /*
         * We just need something here that even the most clever compiler
@@ -675,8 +887,7 @@ dtrace_canstore_statvar(uint64_t addr, size_t sz,
                if (svar == NULL || svar->dtsv_size == 0)
                        continue;
 
-               if (addr - svar->dtsv_data < svar->dtsv_size &&
-                   addr + sz <= svar->dtsv_data + svar->dtsv_size)
+               if (DTRACE_INRANGE(addr, sz, svar->dtsv_data, svar->dtsv_size))
                        return (1);
        }
 
@@ -693,16 +904,11 @@ static int
 dtrace_canstore(uint64_t addr, size_t sz, dtrace_mstate_t *mstate,
     dtrace_vstate_t *vstate)
 {
-       uintptr_t a;
-       size_t s;
-
        /*
         * First, check to see if the address is in scratch space...
         */
-       a = mstate->dtms_scratch_base;
-       s = mstate->dtms_scratch_size;
-
-       if (addr - a < s && addr + sz <= a + s)
+       if (DTRACE_INRANGE(addr, sz, mstate->dtms_scratch_base,
+           mstate->dtms_scratch_size))
                return (1);
 
        /*
@@ -710,10 +916,42 @@ dtrace_canstore(uint64_t addr, size_t sz, dtrace_mstate_t *mstate,
         * up both thread-local variables and any global dynamically-allocated
         * variables.
         */
-       a = (uintptr_t)vstate->dtvs_dynvars.dtds_base;
-       s = vstate->dtvs_dynvars.dtds_size;
-       if (addr - a < s && addr + sz <= a + s)
+       if (DTRACE_INRANGE(addr, sz, (uintptr_t)vstate->dtvs_dynvars.dtds_base,
+           vstate->dtvs_dynvars.dtds_size)) {
+               dtrace_dstate_t *dstate = &vstate->dtvs_dynvars;
+               uintptr_t base = (uintptr_t)dstate->dtds_base +
+                   (dstate->dtds_hashsize * sizeof (dtrace_dynhash_t));
+               uintptr_t chunkoffs;
+
+               /*
+                * Before we assume that we can store here, we need to make
+                * sure that it isn't in our metadata -- storing to our
+                * dynamic variable metadata would corrupt our state.  For
+                * the range to not include any dynamic variable metadata,
+                * it must:
+                *
+                *      (1) Start above the hash table that is at the base of
+                *      the dynamic variable space
+                *
+                *      (2) Have a starting chunk offset that is beyond the
+                *      dtrace_dynvar_t that is at the base of every chunk
+                *
+                *      (3) Not span a chunk boundary
+                *
+                */
+               if (addr < base)
+                       return (0);
+
+               chunkoffs = (addr - base) % dstate->dtds_chunksize;
+
+               if (chunkoffs < sizeof (dtrace_dynvar_t))
+                       return (0);
+
+               if (chunkoffs + sz > dstate->dtds_chunksize)
+                       return (0);
+
                return (1);
+       }
 
        /*
         * Finally, check the static local and global variables.  These checks
@@ -730,30 +968,126 @@ dtrace_canstore(uint64_t addr, size_t sz, dtrace_mstate_t *mstate,
        return (0);
 }
 
+
 /*
- * Compare two strings using safe loads.
+ * Convenience routine to check to see if the address is within a memory
+ * region in which a load may be issued given the user's privilege level;
+ * if not, it sets the appropriate error flags and loads 'addr' into the
+ * illegal value slot.
+ *
+ * DTrace subroutines (DIF_SUBR_*) should use this helper to implement
+ * appropriate memory access protection.
  */
 static int
-dtrace_strncmp(char *s1, char *s2, size_t limit)
+dtrace_canload(uint64_t addr, size_t sz, dtrace_mstate_t *mstate,
+    dtrace_vstate_t *vstate)
 {
-       uint8_t c1, c2;
-       volatile uint16_t *flags;
-
-       if (s1 == s2 || limit == 0)
-               return (0);
+       volatile uint64_t *illval = &cpu_core[CPU->cpu_id].cpuc_dtrace_illval;
 
-       flags = (volatile uint16_t *)&cpu_core[CPU->cpu_id].cpuc_dtrace_flags;
+       /*
+        * If we hold the privilege to read from kernel memory, then
+        * everything is readable.
+        */
+       if ((mstate->dtms_access & DTRACE_ACCESS_KERNEL) != 0)
+               return (1);
 
-       do {
-               if (s1 == NULL)
-                       c1 = '\0';
-               else
-                       c1 = dtrace_load8((uintptr_t)s1++);
+       /*
+        * You can obviously read that which you can store.
+        */
+       if (dtrace_canstore(addr, sz, mstate, vstate))
+               return (1);
 
-               if (s2 == NULL)
-                       c2 = '\0';
-               else
-                       c2 = dtrace_load8((uintptr_t)s2++);
+       /*
+        * We're allowed to read from our own string table.
+        */
+       if (DTRACE_INRANGE(addr, sz, (uintptr_t)mstate->dtms_difo->dtdo_strtab,
+           mstate->dtms_difo->dtdo_strlen))
+               return (1);
+
+       DTRACE_CPUFLAG_SET(CPU_DTRACE_KPRIV);
+       *illval = addr;
+       return (0);
+}
+
+/*
+ * Convenience routine to check to see if a given string is within a memory
+ * region in which a load may be issued given the user's privilege level;
+ * this exists so that we don't need to issue unnecessary dtrace_strlen()
+ * calls in the event that the user has all privileges.
+ */
+static int
+dtrace_strcanload(uint64_t addr, size_t sz, dtrace_mstate_t *mstate,
+    dtrace_vstate_t *vstate)
+{
+       size_t strsz;
+
+       /*
+        * If we hold the privilege to read from kernel memory, then
+        * everything is readable.
+        */
+       if ((mstate->dtms_access & DTRACE_ACCESS_KERNEL) != 0)
+               return (1);
+
+       strsz = 1 + dtrace_strlen((char *)(uintptr_t)addr, sz);
+       if (dtrace_canload(addr, strsz, mstate, vstate))
+               return (1);
+
+       return (0);
+}
+
+/*
+ * Convenience routine to check to see if a given variable is within a memory
+ * region in which a load may be issued given the user's privilege level.
+ */
+static int
+dtrace_vcanload(void *src, dtrace_diftype_t *type, dtrace_mstate_t *mstate,
+    dtrace_vstate_t *vstate)
+{
+       size_t sz;
+       ASSERT(type->dtdt_flags & DIF_TF_BYREF);
+
+       /*
+        * If we hold the privilege to read from kernel memory, then
+        * everything is readable.
+        */
+       if ((mstate->dtms_access & DTRACE_ACCESS_KERNEL) != 0)
+               return (1);
+
+       if (type->dtdt_kind == DIF_TYPE_STRING)
+               sz = dtrace_strlen(src,
+                   vstate->dtvs_state->dts_options[DTRACEOPT_STRSIZE]) + 1;
+       else
+               sz = type->dtdt_size;
+
+       return (dtrace_canload((uintptr_t)src, sz, mstate, vstate));
+}
+
+/*
+ * Compare two strings using safe loads.
+ */
+static int
+dtrace_strncmp(char *s1, char *s2, size_t limit)
+{
+       uint8_t c1, c2;
+       volatile uint16_t *flags;
+
+       if (s1 == s2 || limit == 0)
+               return (0);
+
+       flags = (volatile uint16_t *)&cpu_core[CPU->cpu_id].cpuc_dtrace_flags;
+
+       do {
+               if (s1 == NULL) {
+                       c1 = '\0';
+               } else {
+                       c1 = dtrace_load8((uintptr_t)s1++);
+               }
+
+               if (s2 == NULL) {
+                       c2 = '\0';
+               } else {
+                       c2 = dtrace_load8((uintptr_t)s2++);
+               }
 
                if (c1 != c2)
                        return (c1 - c2);
@@ -771,9 +1105,10 @@ dtrace_strlen(const char *s, size_t lim)
 {
        uint_t len;
 
-       for (len = 0; len != lim; len++)
+       for (len = 0; len != lim; len++) {
                if (dtrace_load8((uintptr_t)s++) == '\0')
                        break;
+       }
 
        return (len);
 }
@@ -866,11 +1201,12 @@ dtrace_vcopy(void *src, void *dst, dtrace_diftype_t *type)
 {
        ASSERT(type->dtdt_flags & DIF_TF_BYREF);
 
-       if (type->dtdt_kind == DIF_TYPE_STRING)
+       if (type->dtdt_kind == DIF_TYPE_STRING) {
                dtrace_strcpy(src, dst, type->dtdt_size);
-       else
+       } else {
                dtrace_bcopy(src, dst, type->dtdt_size);
 }
+}
 
 /*
  * Compare s1 to s2 using safe memory accesses.  The s1 data is assumed to be
@@ -915,6 +1251,93 @@ dtrace_bzero(void *dst, size_t len)
                *cp++ = 0;
 }
 
+static void
+dtrace_add_128(uint64_t *addend1, uint64_t *addend2, uint64_t *sum)
+{
+       uint64_t result[2];
+
+       result[0] = addend1[0] + addend2[0];
+       result[1] = addend1[1] + addend2[1] +
+           (result[0] < addend1[0] || result[0] < addend2[0] ? 1 : 0);
+
+       sum[0] = result[0];
+       sum[1] = result[1];
+}
+
+/*
+ * Shift the 128-bit value in a by b. If b is positive, shift left.
+ * If b is negative, shift right.
+ */
+static void
+dtrace_shift_128(uint64_t *a, int b)
+{
+       uint64_t mask;
+
+       if (b == 0)
+               return;
+
+       if (b < 0) {
+               b = -b;
+               if (b >= 64) {
+                       a[0] = a[1] >> (b - 64);
+                       a[1] = 0;
+               } else {
+                       a[0] >>= b;
+                       mask = 1LL << (64 - b);
+                       mask -= 1;
+                       a[0] |= ((a[1] & mask) << (64 - b));
+                       a[1] >>= b;
+               }
+       } else {
+               if (b >= 64) {
+                       a[1] = a[0] << (b - 64);
+                       a[0] = 0;
+               } else {
+                       a[1] <<= b;
+                       mask = a[0] >> (64 - b);
+                       a[1] |= mask;
+                       a[0] <<= b;
+               }
+       }
+}
+
+/*
+ * The basic idea is to break the 2 64-bit values into 4 32-bit values,
+ * use native multiplication on those, and then re-combine into the
+ * resulting 128-bit value.
+ *
+ * (hi1 << 32 + lo1) * (hi2 << 32 + lo2) =
+ *     hi1 * hi2 << 64 +
+ *     hi1 * lo2 << 32 +
+ *     hi2 * lo1 << 32 +
+ *     lo1 * lo2
+ */
+static void
+dtrace_multiply_128(uint64_t factor1, uint64_t factor2, uint64_t *product)
+{
+       uint64_t hi1, hi2, lo1, lo2;
+       uint64_t tmp[2];
+
+       hi1 = factor1 >> 32;
+       hi2 = factor2 >> 32;
+
+       lo1 = factor1 & DT_MASK_LO;
+       lo2 = factor2 & DT_MASK_LO;
+
+       product[0] = lo1 * lo2;
+       product[1] = hi1 * hi2;
+
+       tmp[0] = hi1 * lo2;
+       tmp[1] = 0;
+       dtrace_shift_128(tmp, 32);
+       dtrace_add_128(product, tmp, product);
+
+       tmp[0] = hi2 * lo1;
+       tmp[1] = 0;
+       dtrace_shift_128(tmp, 32);
+       dtrace_add_128(product, tmp, product);
+}
+
 /*
  * This privilege check should be used by actions and subroutines to
  * verify that the user credentials of the process that enabled the
@@ -931,17 +1354,13 @@ dtrace_priv_proc_common_user(dtrace_state_t *state)
         */
        ASSERT(s_cr != NULL);
 
-#if !defined(__APPLE__)
-       if ((cr = CRED()) != NULL &&
-#else
        if ((cr = dtrace_CRED()) != NULL &&
-#endif /* __APPLE__ */
-           s_cr->cr_uid == cr->cr_uid &&
-           s_cr->cr_uid == cr->cr_ruid &&
-           s_cr->cr_uid == cr->cr_suid &&
-           s_cr->cr_gid == cr->cr_gid &&
-           s_cr->cr_gid == cr->cr_rgid &&
-           s_cr->cr_gid == cr->cr_sgid)
+           posix_cred_get(s_cr)->cr_uid == posix_cred_get(cr)->cr_uid &&
+           posix_cred_get(s_cr)->cr_uid == posix_cred_get(cr)->cr_ruid &&
+           posix_cred_get(s_cr)->cr_uid == posix_cred_get(cr)->cr_suid &&
+           posix_cred_get(s_cr)->cr_gid == posix_cred_get(cr)->cr_gid &&
+           posix_cred_get(s_cr)->cr_gid == posix_cred_get(cr)->cr_rgid &&
+           posix_cred_get(s_cr)->cr_gid == posix_cred_get(cr)->cr_sgid)
                return (1);
 
        return (0);
@@ -956,6 +1375,7 @@ static int
 dtrace_priv_proc_common_zone(dtrace_state_t *state)
 {
        cred_t *cr, *s_cr = state->dts_cred.dcr_cred;
+#pragma unused(cr, s_cr, state) /* __APPLE__ */
 
        /*
         * We should always have a non-NULL state cred here, since if cred
@@ -963,52 +1383,29 @@ dtrace_priv_proc_common_zone(dtrace_state_t *state)
         */
        ASSERT(s_cr != NULL);
 
-#if !defined(__APPLE__)
-       if ((cr = CRED()) != NULL &&
-           s_cr->cr_zone == cr->cr_zone)
-               return (1);
-
-       return (0);
-#else
-#pragma unused(state)
-
-       return 1; /* Darwin doesn't do zones. */
-#endif /* __APPLE__ */
+       return 1; /* APPLE NOTE: Darwin doesn't do zones. */
 }
 
 /*
  * This privilege check should be used by actions and subroutines to
  * verify that the process has not setuid or changed credentials.
  */
-#if !defined(__APPLE__)
-static int
-dtrace_priv_proc_common_nocd()
-{
-       proc_t *proc;
-
-       if ((proc = ttoproc(curthread)) != NULL &&
-           !(proc->p_flag & SNOCD))
-               return (1);
-
-       return (0);
-}
-#else
 static int
 dtrace_priv_proc_common_nocd(void)
 {
        return 1; /* Darwin omits "No Core Dump" flag. */
 }
-#endif /* __APPLE__ */
 
 static int
 dtrace_priv_proc_destructive(dtrace_state_t *state)
 {
        int action = state->dts_cred.dcr_action;
 
-#if defined(__APPLE__)
        if (ISSET(current_proc()->p_lflag, P_LNOATTACH))
                goto bad;
-#endif /* __APPLE__ */
+
+       if (dtrace_is_restricted() && !dtrace_can_attach_to_proc(current_proc()))
+               goto bad;
 
        if (((action & DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE) == 0) &&
            dtrace_priv_proc_common_zone(state) == 0)
@@ -1033,10 +1430,11 @@ bad:
 static int
 dtrace_priv_proc_control(dtrace_state_t *state)
 {
-#if defined(__APPLE__)
        if (ISSET(current_proc()->p_lflag, P_LNOATTACH))
                goto bad;
-#endif /* __APPLE__ */
+
+       if (dtrace_is_restricted() && !dtrace_can_attach_to_proc(current_proc()))
+               goto bad;
 
        if (state->dts_cred.dcr_action & DTRACE_CRA_PROC_CONTROL)
                return (1);
@@ -1046,9 +1444,7 @@ dtrace_priv_proc_control(dtrace_state_t *state)
            dtrace_priv_proc_common_nocd())
                return (1);
 
-#if defined(__APPLE__)
 bad:
-#endif /* __APPLE__ */
        cpu_core[CPU->cpu_id].cpuc_dtrace_flags |= CPU_DTRACE_UPRIV;
 
        return (0);
@@ -1057,24 +1453,26 @@ bad:
 static int
 dtrace_priv_proc(dtrace_state_t *state)
 {
-#if defined(__APPLE__)
        if (ISSET(current_proc()->p_lflag, P_LNOATTACH))
                goto bad;
-#endif /* __APPLE__ */
+
+       if (dtrace_is_restricted() && !dtrace_can_attach_to_proc(current_proc()))
+               goto bad;
 
        if (state->dts_cred.dcr_action & DTRACE_CRA_PROC)
                return (1);
 
-#if defined(__APPLE__)
 bad:
-#endif /* __APPLE__ */
        cpu_core[CPU->cpu_id].cpuc_dtrace_flags |= CPU_DTRACE_UPRIV;
 
        return (0);
 }
 
-#if defined(__APPLE__)
-/* dtrace_priv_proc() omitting the P_LNOATTACH check. For PID and EXECNAME accesses. */
+/*
+ * The P_LNOATTACH check is an Apple specific check.
+ * We need a version of dtrace_priv_proc() that omits
+ * that check for PID and EXECNAME accesses
+ */
 static int
 dtrace_priv_proc_relaxed(dtrace_state_t *state)
 {
@@ -1086,14 +1484,17 @@ dtrace_priv_proc_relaxed(dtrace_state_t *state)
 
        return (0);
 }
-#endif /* __APPLE__ */
 
 static int
 dtrace_priv_kernel(dtrace_state_t *state)
 {
+       if (dtrace_is_restricted())
+               goto bad;
+
        if (state->dts_cred.dcr_action & DTRACE_CRA_KERNEL)
                return (1);
 
+bad:
        cpu_core[CPU->cpu_id].cpuc_dtrace_flags |= CPU_DTRACE_KPRIV;
 
        return (0);
@@ -1102,9 +1503,13 @@ dtrace_priv_kernel(dtrace_state_t *state)
 static int
 dtrace_priv_kernel_destructive(dtrace_state_t *state)
 {
+       if (dtrace_is_restricted())
+               goto bad;
+
        if (state->dts_cred.dcr_action & DTRACE_CRA_KERNEL_DESTRUCTIVE)
                return (1);
 
+bad:
        cpu_core[CPU->cpu_id].cpuc_dtrace_flags |= CPU_DTRACE_KPRIV;
 
        return (0);
@@ -1116,10 +1521,7 @@ dtrace_priv_kernel_destructive(dtrace_state_t *state)
  * clean the dirty dynamic variable lists on all CPUs.  Dynamic variable
  * cleaning is explained in detail in <sys/dtrace_impl.h>.
  */
-#if defined(__APPLE__)
-static 
-#endif /* __APPLE__ */
-void
+static void
 dtrace_dynvar_clean(dtrace_dstate_t *dstate)
 {
        dtrace_dynvar_t *dirty;
@@ -1211,12 +1613,10 @@ dtrace_dynvar_clean(dtrace_dstate_t *dstate)
  * variable can be allocated.  If NULL is returned, the appropriate counter
  * will be incremented.
  */
-#if defined(__APPLE__)
-static 
-#endif /* __APPLE__ */
-dtrace_dynvar_t *
+static dtrace_dynvar_t *
 dtrace_dynvar(dtrace_dstate_t *dstate, uint_t nkeys,
-    dtrace_key_t *key, size_t dsize, dtrace_dynvar_op_t op)
+    dtrace_key_t *key, size_t dsize, dtrace_dynvar_op_t op,
+    dtrace_mstate_t *mstate, dtrace_vstate_t *vstate)
 {
        uint64_t hashval = DTRACE_DYNHASH_VALID;
        dtrace_dynhash_t *hash = dstate->dtds_hash;
@@ -1268,6 +1668,9 @@ dtrace_dynvar(dtrace_dstate_t *dstate, uint_t nkeys,
                        uint64_t j, size = key[i].dttk_size;
                        uintptr_t base = (uintptr_t)key[i].dttk_value;
 
+                       if (!dtrace_canload(base, size, mstate, vstate))
+                               break;
+
                        for (j = 0; j < size; j++) {
                                hashval += dtrace_load8(base + j);
                                hashval += (hashval << 10);
@@ -1276,6 +1679,9 @@ dtrace_dynvar(dtrace_dstate_t *dstate, uint_t nkeys,
                }
        }
 
+       if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_FAULT))
+               return (NULL);
+
        hashval += (hashval << 3);
        hashval ^= (hashval >> 11);
        hashval += (hashval << 15);
@@ -1306,7 +1712,7 @@ dtrace_dynvar(dtrace_dstate_t *dstate, uint_t nkeys,
                        while ((lock = *lockp) & 1)
                                continue;
 
-                       if (dtrace_casptr((void *)lockp,
+                       if (dtrace_casptr((void *)(uintptr_t)lockp,
                            (void *)lock, (void *)(lock + 1)) == (void *)lock)
                                break;
                }
@@ -1662,15 +2068,15 @@ retry:
                dvar->dtdv_next = free;
        } while (dtrace_casptr(&dcpu->dtdsc_dirty, free, dvar) != free);
 
-       return (dtrace_dynvar(dstate, nkeys, key, dsize, op));
+       return (dtrace_dynvar(dstate, nkeys, key, dsize, op, mstate, vstate));
 }
 
 /*ARGSUSED*/
 static void
 dtrace_aggregate_min(uint64_t *oval, uint64_t nval, uint64_t arg)
 {
-#pragma unused(arg)
-       if (nval < *oval)
+#pragma unused(arg) /* __APPLE__ */
+       if ((int64_t)nval < (int64_t)*oval)
                *oval = nval;
 }
 
@@ -1678,8 +2084,8 @@ dtrace_aggregate_min(uint64_t *oval, uint64_t nval, uint64_t arg)
 static void
 dtrace_aggregate_max(uint64_t *oval, uint64_t nval, uint64_t arg)
 {
-#pragma unused(arg)
-       if (nval > *oval)
+#pragma unused(arg) /* __APPLE__ */
+       if ((int64_t)nval > (int64_t)*oval)
                *oval = nval;
 }
 
@@ -1744,20 +2150,114 @@ dtrace_aggregate_lquantize(uint64_t *lquanta, uint64_t nval, uint64_t incr)
        lquanta[levels + 1] += incr;
 }
 
+static int
+dtrace_aggregate_llquantize_bucket(int16_t factor, int16_t low, int16_t high,
+                                   int16_t nsteps, int64_t value)
+{
+       int64_t this = 1, last, next;
+       int base = 1, order;
+
+       for (order = 0; order < low; ++order)
+               this *= factor;
+
+       /*
+        * If our value is less than our factor taken to the power of the
+        * low order of magnitude, it goes into the zeroth bucket.
+        */
+       if (value < this)
+               return 0;
+       else
+               last = this;
+
+       for (this *= factor; order <= high; ++order) {
+               int nbuckets = this > nsteps ? nsteps : this;
+
+               /*
+                * We should not generally get log/linear quantizations
+                * with a high magnitude that allows 64-bits to
+                * overflow, but we nonetheless protect against this
+                * by explicitly checking for overflow, and clamping
+                * our value accordingly.
+                */
+               next = this * factor;
+               if (next < this) {
+                       value = this - 1;
+               }
+
+               /*
+                * If our value lies within this order of magnitude,
+                * determine its position by taking the offset within
+                * the order of magnitude, dividing by the bucket
+                * width, and adding to our (accumulated) base.
+                */
+               if (value < this) {
+                       return (base + (value - last) / (this / nbuckets));
+               }
+
+               base += nbuckets - (nbuckets / factor);
+               last = this;
+               this = next;
+       }
+
+       /*
+        * Our value is greater than or equal to our factor taken to the
+        * power of one plus the high magnitude -- return the top bucket.
+        */
+       return base;
+}
+
+static void
+dtrace_aggregate_llquantize(uint64_t *llquanta, uint64_t nval, uint64_t incr)
+{
+       uint64_t arg    = *llquanta++;
+       uint16_t factor = DTRACE_LLQUANTIZE_FACTOR(arg);
+       uint16_t low    = DTRACE_LLQUANTIZE_LOW(arg);
+       uint16_t high   = DTRACE_LLQUANTIZE_HIGH(arg);
+       uint16_t nsteps = DTRACE_LLQUANTIZE_NSTEP(arg);
+
+       llquanta[dtrace_aggregate_llquantize_bucket(factor, low, high, nsteps, nval)] += incr;
+}
+
 /*ARGSUSED*/
 static void
 dtrace_aggregate_avg(uint64_t *data, uint64_t nval, uint64_t arg)
 {
-#pragma unused(arg)
+#pragma unused(arg) /* __APPLE__ */
+       data[0]++;
+       data[1] += nval;
+}
+
+/*ARGSUSED*/
+static void
+dtrace_aggregate_stddev(uint64_t *data, uint64_t nval, uint64_t arg)
+{
+#pragma unused(arg) /* __APPLE__ */
+       int64_t snval = (int64_t)nval;
+       uint64_t tmp[2];
+
        data[0]++;
        data[1] += nval;
+
+       /*
+        * What we want to say here is:
+        *
+        * data[2] += nval * nval;
+        *
+        * But given that nval is 64-bit, we could easily overflow, so
+        * we do this as 128-bit arithmetic.
+        */
+       if (snval < 0)
+               snval = -snval;
+
+       dtrace_multiply_128((uint64_t)snval, (uint64_t)snval, tmp);
+       dtrace_add_128(data + 2, tmp, data + 2);
 }
 
 /*ARGSUSED*/
 static void
 dtrace_aggregate_count(uint64_t *oval, uint64_t nval, uint64_t arg)
 {
-#pragma unused(nval,arg)
+#pragma unused(nval, arg) /* __APPLE__ */
        *oval = *oval + 1;
 }
 
@@ -1765,7 +2265,7 @@ dtrace_aggregate_count(uint64_t *oval, uint64_t nval, uint64_t arg)
 static void
 dtrace_aggregate_sum(uint64_t *oval, uint64_t nval, uint64_t arg)
 {
-#pragma unused(arg)
+#pragma unused(arg) /* __APPLE__ */
        *oval += nval;
 }
 
@@ -2084,17 +2584,17 @@ dtrace_speculation_commit(dtrace_state_t *state, processorid_t cpu,
        dtrace_speculation_t *spec;
        dtrace_buffer_t *src, *dest;
        uintptr_t daddr, saddr, dlimit;
-       dtrace_speculation_state_t current, new;
+       dtrace_speculation_state_t current,  new = DTRACESPEC_INACTIVE;
        intptr_t offs;
 
        if (which == 0)
                return;
 
-       if (which > state->dts_nspeculations) {
+       if (which > (dtrace_specid_t)state->dts_nspeculations) {
                cpu_core[cpu].cpuc_dtrace_flags |= CPU_DTRACE_ILLOP;
                return;
        }
-
+       
        spec = &state->dts_speculations[which - 1];
        src = &spec->dtsp_buffer[cpu];
        dest = &state->dts_buffer[cpu];
@@ -2200,6 +2700,7 @@ out:
            (current == DTRACESPEC_ACTIVEONE && new == DTRACESPEC_COMMITTING)) {
                uint32_t rval = dtrace_cas32((uint32_t *)&spec->dtsp_state,
                    DTRACESPEC_COMMITTING, DTRACESPEC_INACTIVE);
+#pragma unused(rval) /* __APPLE__ */
 
                ASSERT(rval == DTRACESPEC_COMMITTING);
        }
@@ -2220,13 +2721,13 @@ dtrace_speculation_discard(dtrace_state_t *state, processorid_t cpu,
     dtrace_specid_t which)
 {
        dtrace_speculation_t *spec;
-       dtrace_speculation_state_t current, new;
+       dtrace_speculation_state_t current, new = DTRACESPEC_INACTIVE;
        dtrace_buffer_t *buf;
 
        if (which == 0)
                return;
 
-       if (which > state->dts_nspeculations) {
+       if (which > (dtrace_specid_t)state->dts_nspeculations) {
                cpu_core[cpu].cpuc_dtrace_flags |= CPU_DTRACE_ILLOP;
                return;
        }
@@ -2289,7 +2790,7 @@ dtrace_speculation_clean_here(dtrace_state_t *state)
                return;
        }
 
-       for (i = 0; i < state->dts_nspeculations; i++) {
+       for (i = 0; i < (dtrace_specid_t)state->dts_nspeculations; i++) {
                dtrace_speculation_t *spec = &state->dts_speculations[i];
                dtrace_buffer_t *src = &spec->dtsp_buffer[cpu];
 
@@ -2324,10 +2825,11 @@ dtrace_speculation_clean_here(dtrace_state_t *state)
 static void
 dtrace_speculation_clean(dtrace_state_t *state)
 {
-       int work = 0, rv;
+       int work = 0;
+       uint32_t rv;
        dtrace_specid_t i;
 
-       for (i = 0; i < state->dts_nspeculations; i++) {
+       for (i = 0; i < (dtrace_specid_t)state->dts_nspeculations; i++) {
                dtrace_speculation_t *spec = &state->dts_speculations[i];
 
                ASSERT(!spec->dtsp_cleaning);
@@ -2351,7 +2853,7 @@ dtrace_speculation_clean(dtrace_state_t *state)
         * speculation buffers, as appropriate.  We can now set the state
         * to inactive.
         */
-       for (i = 0; i < state->dts_nspeculations; i++) {
+       for (i = 0; i < (dtrace_specid_t)state->dts_nspeculations; i++) {
                dtrace_speculation_t *spec = &state->dts_speculations[i];
                dtrace_speculation_state_t current, new;
 
@@ -2382,13 +2884,13 @@ dtrace_speculation_buffer(dtrace_state_t *state, processorid_t cpuid,
     dtrace_specid_t which)
 {
        dtrace_speculation_t *spec;
-       dtrace_speculation_state_t current, new;
+       dtrace_speculation_state_t current, new = DTRACESPEC_INACTIVE;
        dtrace_buffer_t *buf;
 
        if (which == 0)
                return (NULL);
 
-       if (which > state->dts_nspeculations) {
+       if (which > (dtrace_specid_t)state->dts_nspeculations) {
                cpu_core[cpuid].cpuc_dtrace_flags |= CPU_DTRACE_ILLOP;
                return (NULL);
        }
@@ -2441,6 +2943,51 @@ dtrace_speculation_buffer(dtrace_state_t *state, processorid_t cpuid,
        return (buf);
 }
 
+/*
+ * Return a string.  In the event that the user lacks the privilege to access
+ * arbitrary kernel memory, we copy the string out to scratch memory so that we
+ * don't fail access checking.
+ *
+ * dtrace_dif_variable() uses this routine as a helper for various
+ * builtin values such as 'execname' and 'probefunc.'
+ */
+static
+uintptr_t
+dtrace_dif_varstr(uintptr_t addr, dtrace_state_t *state,
+    dtrace_mstate_t *mstate)
+{
+       uint64_t size = state->dts_options[DTRACEOPT_STRSIZE];
+       uintptr_t ret;
+       size_t strsz;
+
+       /*
+        * The easy case: this probe is allowed to read all of memory, so
+        * we can just return this as a vanilla pointer.
+        */
+       if ((mstate->dtms_access & DTRACE_ACCESS_KERNEL) != 0)
+               return (addr);
+
+       /*
+        * This is the tougher case: we copy the string in question from
+        * kernel memory into scratch memory and return it that way: this
+        * ensures that we won't trip up when access checking tests the
+        * BYREF return value.
+        */
+       strsz = dtrace_strlen((char *)addr, size) + 1;
+
+       if (mstate->dtms_scratch_ptr + strsz >
+           mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+               DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
+               return (0);
+       }
+
+       dtrace_strcpy((const void *)addr, (void *)mstate->dtms_scratch_ptr,
+           strsz);
+       ret = mstate->dtms_scratch_ptr;
+       mstate->dtms_scratch_ptr += strsz;
+       return (ret);
+}
+
 /*
  * This function implements the DIF emulator's variable lookups.  The emulator
  * passes a reserved variable identifier and optional built-in array index.
@@ -2463,12 +3010,10 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                ASSERT(mstate->dtms_present & DTRACE_MSTATE_ARGS);
                if (ndx >= sizeof (mstate->dtms_arg) /
                    sizeof (mstate->dtms_arg[0])) {
-#if !defined(__APPLE__)
-                       int aframes = mstate->dtms_probe->dtpr_aframes + 2;
-#else
-                       /* Account for introduction of __dtrace_probe() on xnu. */
+                       /*
+                        * APPLE NOTE: Account for introduction of __dtrace_probe()
+                        */
                        int aframes = mstate->dtms_probe->dtpr_aframes + 3;
-#endif /* __APPLE__ */
                        dtrace_provider_t *pv;
                        uint64_t val;
 
@@ -2477,12 +3022,11 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                                val = pv->dtpv_pops.dtps_getargval(pv->dtpv_arg,
                                    mstate->dtms_probe->dtpr_id,
                                    mstate->dtms_probe->dtpr_arg, ndx, aframes);
-#if defined(__APPLE__)
-                       /* Special case access of arg5 as passed to dtrace_probeid_error (which see.) */
+                       /* Special case access of arg5 as passed to dtrace_probe_error() (which see.) */
                        else if (mstate->dtms_probe->dtpr_id == dtrace_probeid_error && ndx == 5) {
-                               return ((dtrace_state_t *)(mstate->dtms_arg[0]))->dts_arg_error_illval;
+                               return ((dtrace_state_t *)(uintptr_t)(mstate->dtms_arg[0]))->dts_arg_error_illval;
                        }
-#endif /* __APPLE__ */
+
                        else
                                val = dtrace_getarg(ndx, aframes);
 
@@ -2503,22 +3047,6 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
 
                return (mstate->dtms_arg[ndx]);
 
-#if !defined(__APPLE__)
-       case DIF_VAR_UREGS: {
-               klwp_t *lwp;
-
-               if (!dtrace_priv_proc(state))
-                       return (0);
-
-               if ((lwp = curthread->t_lwp) == NULL) {
-                       DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
-                       cpu_core[CPU->cpu_id].cpuc_dtrace_illval = NULL;
-                       return (0);
-               }
-
-               return (dtrace_getreg(lwp->lwp_regs, ndx));
-       }
-#else
        case DIF_VAR_UREGS: {
                thread_t thread;
 
@@ -2533,20 +3061,13 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
 
                return (dtrace_getreg(find_user_regs(thread), ndx));
        }
-#endif /* __APPLE__ */
 
-#if !defined(__APPLE__)
-       case DIF_VAR_CURTHREAD:
-               if (!dtrace_priv_kernel(state))
-                       return (0);
-               return ((uint64_t)(uintptr_t)curthread);
-#else
+
        case DIF_VAR_CURTHREAD:
                if (!dtrace_priv_kernel(state))
                        return (0);
 
                return ((uint64_t)(uintptr_t)current_thread());
-#endif /* __APPLE__ */
 
        case DIF_VAR_TIMESTAMP:
                if (!(mstate->dtms_present & DTRACE_MSTATE_TIMESTAMP)) {
@@ -2555,15 +3076,9 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                }
                return (mstate->dtms_timestamp);
 
-#if !defined(__APPLE__)
-       case DIF_VAR_VTIMESTAMP:
-               ASSERT(dtrace_vtime_references != 0);
-               return (curthread->t_dtrace_vtime);
-#else
        case DIF_VAR_VTIMESTAMP:
                ASSERT(dtrace_vtime_references != 0);
                return (dtrace_get_thread_vtime(current_thread()));
-#endif /* __APPLE__ */
 
        case DIF_VAR_WALLTIMESTAMP:
                if (!(mstate->dtms_present & DTRACE_MSTATE_WALLTIMESTAMP)) {
@@ -2572,6 +3087,13 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                }
                return (mstate->dtms_walltimestamp);
 
+       case DIF_VAR_MACHTIMESTAMP:
+               if (!(mstate->dtms_present & DTRACE_MSTATE_MACHTIMESTAMP)) {
+                       mstate->dtms_machtimestamp = mach_absolute_time();
+                       mstate->dtms_present |= DTRACE_MSTATE_MACHTIMESTAMP;
+               }
+               return (mstate->dtms_machtimestamp);
+
        case DIF_VAR_IPL:
                if (!dtrace_priv_kernel(state))
                        return (0);
@@ -2593,12 +3115,10 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                if (!dtrace_priv_kernel(state))
                        return (0);
                if (!(mstate->dtms_present & DTRACE_MSTATE_STACKDEPTH)) {
-#if !defined(__APPLE__)
-                       int aframes = mstate->dtms_probe->dtpr_aframes + 2;
-#else
-                       /* Account for introduction of __dtrace_probe() on xnu. */
+                       /*
+                        * APPLE NOTE: Account for introduction of __dtrace_probe()
+                        */
                        int aframes = mstate->dtms_probe->dtpr_aframes + 3;
-#endif /* __APPLE__ */
 
                        mstate->dtms_stackdepth = dtrace_getstackdepth(aframes);
                        mstate->dtms_present |= DTRACE_MSTATE_STACKDEPTH;
@@ -2629,12 +3149,10 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                if (!dtrace_priv_kernel(state))
                        return (0);
                if (!(mstate->dtms_present & DTRACE_MSTATE_CALLER)) {
-#if !defined(__APPLE__)
-                       int aframes = mstate->dtms_probe->dtpr_aframes + 2;
-#else
-                       /* Account for introduction of __dtrace_probe() on xnu. */
+                       /*
+                        * APPLE NOTE: Account for introduction of __dtrace_probe()
+                        */
                        int aframes = mstate->dtms_probe->dtpr_aframes + 3;
-#endif /* __APPLE__ */
 
                        if (!DTRACE_ANCHORED(mstate->dtms_probe)) {
                                /*
@@ -2649,7 +3167,7 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                                    (uint32_t *)(uintptr_t)mstate->dtms_arg[0]);
                                mstate->dtms_caller = caller[1];
                        } else if ((mstate->dtms_caller =
-                           dtrace_caller(aframes)) == -1) {
+                               dtrace_caller(aframes)) == (uintptr_t)-1) {
                                /*
                                 * We have failed to do this the quick way;
                                 * we must resort to the slower approach of
@@ -2679,8 +3197,10 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                         * uint64_t will contain the caller, which is what
                         * we're after.
                         */
-                       ustack[2] = NULL;
+                       ustack[2] = 0;
+                       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
                        dtrace_getupcstack(ustack, 3);
+                       DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
                        mstate->dtms_ucaller = ustack[2];
                        mstate->dtms_present |= DTRACE_MSTATE_UCALLER;
                }
@@ -2689,48 +3209,28 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
 
        case DIF_VAR_PROBEPROV:
                ASSERT(mstate->dtms_present & DTRACE_MSTATE_PROBE);
-               return ((uint64_t)(uintptr_t)
-                   mstate->dtms_probe->dtpr_provider->dtpv_name);
+               return (dtrace_dif_varstr(
+                   (uintptr_t)mstate->dtms_probe->dtpr_provider->dtpv_name,
+                   state, mstate));
 
        case DIF_VAR_PROBEMOD:
                ASSERT(mstate->dtms_present & DTRACE_MSTATE_PROBE);
-               return ((uint64_t)(uintptr_t)
-                   mstate->dtms_probe->dtpr_mod);
+               return (dtrace_dif_varstr(
+                   (uintptr_t)mstate->dtms_probe->dtpr_mod,
+                   state, mstate));
 
        case DIF_VAR_PROBEFUNC:
                ASSERT(mstate->dtms_present & DTRACE_MSTATE_PROBE);
-               return ((uint64_t)(uintptr_t)
-                   mstate->dtms_probe->dtpr_func);
+               return (dtrace_dif_varstr(
+                   (uintptr_t)mstate->dtms_probe->dtpr_func,
+                   state, mstate));
 
        case DIF_VAR_PROBENAME:
                ASSERT(mstate->dtms_present & DTRACE_MSTATE_PROBE);
-               return ((uint64_t)(uintptr_t)
-                   mstate->dtms_probe->dtpr_name);
-
-#if !defined(__APPLE__)
-       case DIF_VAR_PID:
-               if (!dtrace_priv_proc(state))
-                       return (0);
-
-               /*
-                * Note that we are assuming that an unanchored probe is
-                * always due to a high-level interrupt.  (And we're assuming
-                * that there is only a single high level interrupt.)
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return (pid0.pid_id);
-
-               /*
-                * It is always safe to dereference one's own t_procp pointer:
-                * it always points to a valid, allocated proc structure.
-                * Further, it is always safe to dereference the p_pidp member
-                * of one's own proc structure.  (These are truisms becuase
-                * threads and processes don't clean up their own state --
-                * they leave that task to whomever reaps them.)
-                */
-               return ((uint64_t)curthread->t_procp->p_pidp->pid_id);
+               return (dtrace_dif_varstr(
+                   (uintptr_t)mstate->dtms_probe->dtpr_name,
+                   state, mstate));
 
-#else
        case DIF_VAR_PID:
                if (!dtrace_priv_proc_relaxed(state))
                        return (0);
@@ -2744,22 +3244,8 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                        /* Anchored probe that fires while on an interrupt accrues to process 0 */
                        return 0; 
 
-               return ((uint64_t)proc_selfpid());
-#endif /* __APPLE__ */
-
-#if !defined(__APPLE__)
-       case DIF_VAR_PPID:
-               if (!dtrace_priv_proc(state))
-                       return (0);
-
-               /*
-                * See comment in DIF_VAR_PID.
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return (pid0.pid_id);
+               return ((uint64_t)dtrace_proc_selfpid());
 
-               return ((uint64_t)curthread->t_procp->p_ppid);
-#else
        case DIF_VAR_PPID:
                if (!dtrace_priv_proc_relaxed(state))
                        return (0);
@@ -2770,58 +3256,36 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
                        return (0);
 
-               return ((uint64_t)(uintptr_t)(current_proc()->p_ppid));
-#endif /* __APPLE__ */
+               return ((uint64_t)dtrace_proc_selfppid());
 
-#if !defined(__APPLE__)
        case DIF_VAR_TID:
-               /*
-                * See comment in DIF_VAR_PID.
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return (0);
+               /* We do not need to check for null current_thread() */
+               return thread_tid(current_thread()); /* globally unique */
 
-               return ((uint64_t)curthread->t_tid);
-#else
-       case DIF_VAR_TID:
-               /*
-                * See comment in DIF_VAR_PID.
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
+       case DIF_VAR_PTHREAD_SELF:
+               if (!dtrace_priv_proc(state))
                        return (0);
 
-               return ((uint64_t)(uintptr_t)current_thread()); /* Is user's (pthread_t)t->kernel_thread */
-#endif /* __APPLE__ */
+               /* Not currently supported, but we should be able to delta the dispatchqaddr and dispatchqoffset to get pthread_self */
+               return 0;
 
-#if !defined(__APPLE__)
-       case DIF_VAR_EXECNAME:
+       case DIF_VAR_DISPATCHQADDR:
                if (!dtrace_priv_proc(state))
                        return (0);
 
-               /*
-                * See comment in DIF_VAR_PID.
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return ((uint64_t)(uintptr_t)p0.p_user.u_comm);
+               /* We do not need to check for null current_thread() */
+               return thread_dispatchqaddr(current_thread());
 
-               /*
-                * It is always safe to dereference one's own t_procp pointer:
-                * it always points to a valid, allocated proc structure.
-                * (This is true because threads don't clean up their own
-                * state -- they leave that task to whomever reaps them.)
-                */
-               return ((uint64_t)(uintptr_t)
-                   curthread->t_procp->p_user.u_comm);
-#else
        case DIF_VAR_EXECNAME:
        {
                char *xname = (char *)mstate->dtms_scratch_ptr;
                size_t scratch_size = MAXCOMLEN+1;
                
                /* The scratch allocation's lifetime is that of the clause. */
-               if (mstate->dtms_scratch_ptr + scratch_size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size)
+               if (!DTRACE_INSCRATCH(mstate, scratch_size)) {
+                       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
                        return 0;
+               }
                        
                if (!dtrace_priv_proc_relaxed(state))
                        return (0);
@@ -2831,77 +3295,43 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
 
                return ((uint64_t)(uintptr_t)xname);
        }
-#endif /* __APPLE__ */
-#if !defined(__APPLE__)
-       case DIF_VAR_ZONENAME:
-               if (!dtrace_priv_proc(state))
-                       return (0);
-
-               /*
-                * See comment in DIF_VAR_PID.
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return ((uint64_t)(uintptr_t)p0.p_zone->zone_name);
 
-               /*
-                * It is always safe to dereference one's own t_procp pointer:
-                * it always points to a valid, allocated proc structure.
-                * (This is true because threads don't clean up their own
-                * state -- they leave that task to whomever reaps them.)
-                */
-               return ((uint64_t)(uintptr_t)
-                   curthread->t_procp->p_zone->zone_name);
 
-#else
        case DIF_VAR_ZONENAME:
-               if (!dtrace_priv_proc(state))
-                       return (0);
-               
-               return ((uint64_t)(uintptr_t)NULL); /* Darwin doesn't do "zones" */
-#endif /* __APPLE__ */
+        {
+                /* scratch_size is equal to length('global') + 1 for the null-terminator. */
+                char *zname = (char *)mstate->dtms_scratch_ptr;
+                size_t scratch_size = 6 + 1;
 
-#if !defined(__APPLE__)
-       case DIF_VAR_UID:
                if (!dtrace_priv_proc(state))
                        return (0);
 
-               /*
-                * See comment in DIF_VAR_PID.
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return ((uint64_t)p0.p_cred->cr_uid);
+                /* The scratch allocation's lifetime is that of the clause. */
+                if (!DTRACE_INSCRATCH(mstate, scratch_size)) {
+                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
+                        return 0;
+                }
 
-               return ((uint64_t)curthread->t_cred->cr_uid);
-#else
-       case DIF_VAR_UID:
-               if (!dtrace_priv_proc(state))
-                       return (0);
+                mstate->dtms_scratch_ptr += scratch_size;
 
-               /*
-                * See comment in DIF_VAR_PID.
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return (0);
+                /* The kernel does not provide zonename, it will always return 'global'. */
+                strlcpy(zname, "global", scratch_size);
 
-               if (dtrace_CRED() != NULL)
-                       return ((uint64_t)kauth_getuid());
-               else
-                       return -1LL;
-#endif /* __APPLE__ */
+                return ((uint64_t)(uintptr_t)zname);
+        }
 
-#if !defined(__APPLE__)
-       case DIF_VAR_GID:
-               if (!dtrace_priv_proc(state))
+       case DIF_VAR_UID:
+               if (!dtrace_priv_proc_relaxed(state))
                        return (0);
 
                /*
                 * See comment in DIF_VAR_PID.
                 */
                if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return ((uint64_t)p0.p_cred->cr_gid);
+                       return (0);
+
+               return ((uint64_t) dtrace_proc_selfruid());
 
-               return ((uint64_t)curthread->t_cred->cr_gid);
-#else
        case DIF_VAR_GID:
                if (!dtrace_priv_proc(state))
                        return (0);
@@ -2913,29 +3343,14 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                        return (0);
 
                if (dtrace_CRED() != NULL)
+                       /* Credential does not require lazy initialization. */
                        return ((uint64_t)kauth_getgid());
-               else
-                       return -1LL;
-#endif /* __APPLE__ */
-
-#if !defined(__APPLE__)
-       case DIF_VAR_ERRNO: {
-               klwp_t *lwp;
-               if (!dtrace_priv_proc(state))
-                       return (0);
-
-               /*
-                * See comment in DIF_VAR_PID.
-                */
-               if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
-                       return (0);
-
-               if ((lwp = curthread->t_lwp) == NULL)
-                       return (0);
+               else {
+                       /* proc_lock would be taken under kauth_cred_proc_ref() in kauth_cred_get(). */
+                       DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
+                       return -1ULL;
+               }
 
-               return ((uint64_t)lwp->lwp_errno);
-       }
-#else
        case DIF_VAR_ERRNO: {
                uthread_t uthread = (uthread_t)get_bsdthread_info(current_thread());
                if (!dtrace_priv_proc(state))
@@ -2947,9 +3362,13 @@ dtrace_dif_variable(dtrace_mstate_t *mstate, dtrace_state_t *state, uint64_t v,
                if (DTRACE_ANCHORED(mstate->dtms_probe) && CPU_ON_INTR(CPU))
                        return (0);
 
-               return (uthread ? uthread->t_dtrace_errno : -1);
+               if (uthread)
+                       return (uint64_t)uthread->t_dtrace_errno;
+               else {
+                       DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
+                       return -1ULL;
+               }
        }
-#endif /* __APPLE__ */
 
        default:
                DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
@@ -2970,11 +3389,8 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
     dtrace_mstate_t *mstate, dtrace_state_t *state)
 {
        volatile uint16_t *flags = &cpu_core[CPU->cpu_id].cpuc_dtrace_flags;
-#if !defined(__APPLE__)
-       volatile uintptr_t *illval = &cpu_core[CPU->cpu_id].cpuc_dtrace_illval;
-#else
        volatile uint64_t *illval = &cpu_core[CPU->cpu_id].cpuc_dtrace_illval;
-#endif /* __APPLE__ */
+       dtrace_vstate_t *vstate = &state->dts_vstate;
 
 #if !defined(__APPLE__)
        union {
@@ -2987,7 +3403,7 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                uintptr_t rw;
        } r;
 #else
-/* XXX awaits lock/mutex work */
+/* FIXME: awaits lock/mutex work */
 #endif /* __APPLE__ */
 
        switch (subr) {
@@ -2997,6 +3413,12 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
 
 #if !defined(__APPLE__)
        case DIF_SUBR_MUTEX_OWNED:
+               if (!dtrace_canload(tupregs[0].dttk_value, sizeof (kmutex_t),
+                   mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                m.mx = dtrace_load64(tupregs[0].dttk_value);
                if (MUTEX_TYPE_ADAPTIVE(&m.mi))
                        regs[rd] = MUTEX_OWNER(&m.mi) != MUTEX_NO_OWNER;
@@ -3005,6 +3427,12 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                break;
 
        case DIF_SUBR_MUTEX_OWNER:
+               if (!dtrace_canload(tupregs[0].dttk_value, sizeof (kmutex_t),
+                   mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                m.mx = dtrace_load64(tupregs[0].dttk_value);
                if (MUTEX_TYPE_ADAPTIVE(&m.mi) &&
                    MUTEX_OWNER(&m.mi) != MUTEX_NO_OWNER)
@@ -3014,11 +3442,23 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                break;
 
        case DIF_SUBR_MUTEX_TYPE_ADAPTIVE:
+               if (!dtrace_canload(tupregs[0].dttk_value, sizeof (kmutex_t),
+                   mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                m.mx = dtrace_load64(tupregs[0].dttk_value);
                regs[rd] = MUTEX_TYPE_ADAPTIVE(&m.mi);
                break;
 
        case DIF_SUBR_MUTEX_TYPE_SPIN:
+               if (!dtrace_canload(tupregs[0].dttk_value, sizeof (kmutex_t),
+                   mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                m.mx = dtrace_load64(tupregs[0].dttk_value);
                regs[rd] = MUTEX_TYPE_SPIN(&m.mi);
                break;
@@ -3026,22 +3466,40 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
        case DIF_SUBR_RW_READ_HELD: {
                uintptr_t tmp;
 
+               if (!dtrace_canload(tupregs[0].dttk_value, sizeof (uintptr_t),
+                   mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                r.rw = dtrace_loadptr(tupregs[0].dttk_value);
                regs[rd] = _RW_READ_HELD(&r.ri, tmp);
                break;
        }
 
        case DIF_SUBR_RW_WRITE_HELD:
+               if (!dtrace_canload(tupregs[0].dttk_value, sizeof (krwlock_t),
+                   mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                r.rw = dtrace_loadptr(tupregs[0].dttk_value);
                regs[rd] = _RW_WRITE_HELD(&r.ri);
                break;
 
        case DIF_SUBR_RW_ISWRITER:
+               if (!dtrace_canload(tupregs[0].dttk_value, sizeof (krwlock_t),
+                   mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                r.rw = dtrace_loadptr(tupregs[0].dttk_value);
                regs[rd] = _RW_ISWRITER(&r.ri);
                break;
 #else
-/* XXX awaits lock/mutex work */
+/* FIXME: awaits lock/mutex work */
 #endif /* __APPLE__ */
 
        case DIF_SUBR_BCOPY: {
@@ -3059,6 +3517,11 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                        break;
                }
 
+               if (!dtrace_canload(src, size, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                dtrace_bcopy((void *)src, (void *)dest, size);
                break;
        }
@@ -3075,21 +3538,22 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                 * probes will not activate in user contexts to which the
                 * enabling user does not have permissions.
                 */
-               if (mstate->dtms_scratch_ptr + scratch_size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+
+               /*
+                * Rounding up the user allocation size could have overflowed
+                * a large, bogus allocation (like -1ULL) to 0.
+                */
+               if (scratch_size < size ||
+                   !DTRACE_INSCRATCH(mstate, scratch_size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
+                       regs[rd] = 0;
                        break;
                }
 
                if (subr == DIF_SUBR_COPYIN) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-#if !defined(__APPLE__)
-                       dtrace_copyin(tupregs[0].dttk_value, dest, size);
-#else
                        if (dtrace_priv_proc(state))
-                               dtrace_copyin(tupregs[0].dttk_value, dest, size);
-#endif /* __APPLE__ */
+                               dtrace_copyin(tupregs[0].dttk_value, dest, size, flags);
                        DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
                }
 
@@ -3114,12 +3578,8 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                }
 
                DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-#if !defined(__APPLE__)
-               dtrace_copyin(tupregs[0].dttk_value, dest, size);
-#else
                if (dtrace_priv_proc(state))
-                       dtrace_copyin(tupregs[0].dttk_value, dest, size);
-#endif /* __APPLE__ */
+                       dtrace_copyin(tupregs[0].dttk_value, dest, size, flags);
                DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
                break;
        }
@@ -3136,20 +3596,15 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                 * probes will not activate in user contexts to which the
                 * enabling user does not have permissions.
                 */
-               if (mstate->dtms_scratch_ptr + size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+               if (!DTRACE_INSCRATCH(mstate, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
+                       regs[rd] = 0;
                        break;
                }
 
                DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-#if !defined(__APPLE__)
-               dtrace_copyinstr(tupregs[0].dttk_value, dest, size);
-#else
                if (dtrace_priv_proc(state))
-                       dtrace_copyinstr(tupregs[0].dttk_value, dest, size);
-#endif /* __APPLE__ */
+                       dtrace_copyinstr(tupregs[0].dttk_value, dest, size, flags);
                DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
 
                ((char *)dest)[size - 1] = '\0';
@@ -3158,87 +3613,14 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                break;
        }
 
-#if !defined(__APPLE__)
-       case DIF_SUBR_MSGSIZE:
-       case DIF_SUBR_MSGDSIZE: {
-               uintptr_t baddr = tupregs[0].dttk_value, daddr;
-               uintptr_t wptr, rptr;
-               size_t count = 0;
-               int cont = 0;
-
-               while (baddr != NULL && !(*flags & CPU_DTRACE_FAULT)) {
-                       wptr = dtrace_loadptr(baddr +
-                           offsetof(mblk_t, b_wptr));
-
-                       rptr = dtrace_loadptr(baddr +
-                           offsetof(mblk_t, b_rptr));
-
-                       if (wptr < rptr) {
-                               *flags |= CPU_DTRACE_BADADDR;
-                               *illval = tupregs[0].dttk_value;
-                               break;
-                       }
-
-                       daddr = dtrace_loadptr(baddr +
-                           offsetof(mblk_t, b_datap));
-
-                       baddr = dtrace_loadptr(baddr +
-                           offsetof(mblk_t, b_cont));
-
-                       /*
-                        * We want to prevent against denial-of-service here,
-                        * so we're only going to search the list for
-                        * dtrace_msgdsize_max mblks.
-                        */
-                       if (cont++ > dtrace_msgdsize_max) {
-                               *flags |= CPU_DTRACE_ILLOP;
-                               break;
-                       }
-
-                       if (subr == DIF_SUBR_MSGDSIZE) {
-                               if (dtrace_load8(daddr +
-                                   offsetof(dblk_t, db_type)) != M_DATA)
-                                       continue;
-                       }
-
-                       count += wptr - rptr;
-               }
-
-               if (!(*flags & CPU_DTRACE_FAULT))
-                       regs[rd] = count;
-
-               break;
-       }
-#else
        case DIF_SUBR_MSGSIZE:
        case DIF_SUBR_MSGDSIZE: {
                /* Darwin does not implement SysV streams messages */
+               DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
                regs[rd] = 0;
                break;
        }
-#endif /* __APPLE__ */
-
-#if !defined(__APPLE__)
-       case DIF_SUBR_PROGENYOF: {
-               pid_t pid = tupregs[0].dttk_value;
-               proc_t *p;
-               int rval = 0;
-
-               DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-
-               for (p = curthread->t_procp; p != NULL; p = p->p_parent) {
-                       if (p->p_pidp->pid_id == pid) {
-                               rval = 1;
-                               break;
-                       }
-               }
-
-               DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
 
-               regs[rd] = rval;
-               break;
-       }
-#else
        case DIF_SUBR_PROGENYOF: {
                pid_t pid = tupregs[0].dttk_value;
                struct proc *p = current_proc();
@@ -3267,23 +3649,22 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                regs[rd] = rval;
                break;
        }
-#endif /* __APPLE__ */
 
        case DIF_SUBR_SPECULATION:
                regs[rd] = dtrace_speculation(state);
                break;
 
-#if !defined(__APPLE__)
+
        case DIF_SUBR_COPYOUT: {
                uintptr_t kaddr = tupregs[0].dttk_value;
-               uintptr_t uaddr = tupregs[1].dttk_value;
+               user_addr_t uaddr = tupregs[1].dttk_value;
                uint64_t size = tupregs[2].dttk_value;
 
                if (!dtrace_destructive_disallow &&
                    dtrace_priv_proc_control(state) &&
                    !dtrace_istoxic(kaddr, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-                       dtrace_copyout(kaddr, uaddr, size);
+                       dtrace_copyout(kaddr, uaddr, size, flags);
                        DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
                }
                break;
@@ -3291,56 +3672,35 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
 
        case DIF_SUBR_COPYOUTSTR: {
                uintptr_t kaddr = tupregs[0].dttk_value;
-               uintptr_t uaddr = tupregs[1].dttk_value;
+               user_addr_t uaddr = tupregs[1].dttk_value;
                uint64_t size = tupregs[2].dttk_value;
 
                if (!dtrace_destructive_disallow &&
                    dtrace_priv_proc_control(state) &&
                    !dtrace_istoxic(kaddr, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-                       dtrace_copyoutstr(kaddr, uaddr, size);
+                       dtrace_copyoutstr(kaddr, uaddr, size, flags);
                        DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
                }
                break;
        }
-#else
-       case DIF_SUBR_COPYOUT: {
-               uintptr_t kaddr = tupregs[0].dttk_value;
-               user_addr_t uaddr = tupregs[1].dttk_value;
-               uint64_t size = tupregs[2].dttk_value;
 
-               if (!dtrace_destructive_disallow &&
-                   dtrace_priv_proc_control(state) &&
-                   !dtrace_istoxic(kaddr, size)) {
-                       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-                       dtrace_copyout(kaddr, uaddr, size);
-                       DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
+       case DIF_SUBR_STRLEN: {
+               size_t sz;
+               uintptr_t addr = (uintptr_t)tupregs[0].dttk_value;
+               sz = dtrace_strlen((char *)addr,
+                   state->dts_options[DTRACEOPT_STRSIZE]);
+
+               if (!dtrace_canload(addr, sz + 1, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
                }
+
+               regs[rd] = sz;
+
                break;
        }
 
-       case DIF_SUBR_COPYOUTSTR: {
-               uintptr_t kaddr = tupregs[0].dttk_value;
-               user_addr_t uaddr = tupregs[1].dttk_value;
-               uint64_t size = tupregs[2].dttk_value;
-
-               if (!dtrace_destructive_disallow &&
-                   dtrace_priv_proc_control(state) &&
-                   !dtrace_istoxic(kaddr, size)) {
-                       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
-                       dtrace_copyoutstr(kaddr, uaddr, size);
-                       DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
-               }
-               break;
-       }
-#endif /* __APPLE__ */
-
-       case DIF_SUBR_STRLEN:
-               regs[rd] = dtrace_strlen((char *)(uintptr_t)
-                   tupregs[0].dttk_value,
-                   state->dts_options[DTRACEOPT_STRSIZE]);
-               break;
-
        case DIF_SUBR_STRCHR:
        case DIF_SUBR_STRRCHR: {
                /*
@@ -3350,11 +3710,12 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                 * is DIF_SUBR_STRRCHR, we will look for the last occurrence
                 * of the specified character instead of the first.
                 */
+               uintptr_t saddr = tupregs[0].dttk_value;
                uintptr_t addr = tupregs[0].dttk_value;
                uintptr_t limit = addr + state->dts_options[DTRACEOPT_STRSIZE];
                char c, target = (char)tupregs[1].dttk_value;
 
-               for (regs[rd] = NULL; addr < limit; addr++) {
+               for (regs[rd] = 0; addr < limit; addr++) {
                        if ((c = dtrace_load8(addr)) == target) {
                                regs[rd] = addr;
 
@@ -3366,6 +3727,11 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                                break;
                }
 
+               if (!dtrace_canload(saddr, addr - saddr, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                break;
        }
 
@@ -3392,6 +3758,17 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
 
                regs[rd] = notfound;
 
+               if (!dtrace_canload((uintptr_t)addr, len + 1, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
+               if (!dtrace_canload((uintptr_t)substr, sublen + 1, mstate,
+                   vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
                /*
                 * strstr() and index()/rindex() have similar semantics if
                 * both strings are the empty string: strstr() returns a
@@ -3466,13 +3843,13 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                                                break;
                                        }
 
-                                       if (pos > len)
+                                       if ((size_t)pos > len)
                                                pos = len;
                                } else {
                                        if (pos < 0)
                                                pos = 0;
 
-                                       if (pos >= len) {
+                                       if ((size_t)pos >= len) {
                                                if (sublen == 0)
                                                        regs[rd] = len;
                                                break;
@@ -3513,18 +3890,26 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                uintptr_t tokaddr = tupregs[1].dttk_value;
                uint64_t size = state->dts_options[DTRACEOPT_STRSIZE];
                uintptr_t limit, toklimit = tokaddr + size;
-               uint8_t c, tokmap[32];   /* 256 / 8 */
                char *dest = (char *)mstate->dtms_scratch_ptr;
-               int i;
+               uint8_t c='\0', tokmap[32];      /* 256 / 8 */
+               uint64_t i = 0;
+
+               /*
+                * Check both the token buffer and (later) the input buffer,
+                * since both could be non-scratch addresses.
+                */
+               if (!dtrace_strcanload(tokaddr, size, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
 
-               if (mstate->dtms_scratch_ptr + size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+               if (!DTRACE_INSCRATCH(mstate, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
+                       regs[rd] = 0;
                        break;
                }
 
-               if (addr == NULL) {
+               if (addr == 0) {
                        /*
                         * If the address specified is NULL, we use our saved
                         * strtok pointer from the mstate.  Note that this
@@ -3533,6 +3918,19 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                         * it behaves like an implicit clause-local variable.
                         */
                        addr = mstate->dtms_strtok;
+               } else {
+                       /*
+                        * If the user-specified address is non-NULL we must
+                        * access check it.  This is the only time we have
+                        * a chance to do so, since this address may reside
+                        * in the string table of this clause-- future calls
+                        * (when we fetch addr from mstate->dtms_strtok)
+                        * would fail this access check.
+                        */
+                       if (!dtrace_strcanload(addr, size, mstate, vstate)) {
+                               regs[rd] = 0;
+                               break;
+                       }
                }
 
                /*
@@ -3570,8 +3968,8 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                         * We return NULL in this case, and we set the saved
                         * address to NULL as well.
                         */
-                       regs[rd] = NULL;
-                       mstate->dtms_strtok = NULL;
+                       regs[rd] = 0;
+                       mstate->dtms_strtok = 0;
                        break;
                }
 
@@ -3606,16 +4004,20 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                size_t len = dtrace_strlen((char *)s, size);
                int64_t i = 0;
 
-               if (nargs <= 2)
-                       remaining = (int64_t)size;
+               if (!dtrace_canload(s, len + 1, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
 
-               if (mstate->dtms_scratch_ptr + size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+               if (!DTRACE_INSCRATCH(mstate, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
+                       regs[rd] = 0;
                        break;
                }
 
+               if (nargs <= 2)
+                       remaining = (int64_t)size;
+
                if (index < 0) {
                        index += len;
 
@@ -3625,263 +4027,64 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                        }
                }
 
-               if (index >= len || index < 0)
-                       index = len;
-
-               for (d[0] = '\0'; remaining > 0; remaining--) {
-                       if ((d[i++] = dtrace_load8(s++ + index)) == '\0')
-                               break;
+               if ((size_t)index >= len || index < 0) {
+                       remaining = 0;
+               } else if (remaining < 0) {
+                       remaining += len - index;
+               } else if ((uint64_t)index + (uint64_t)remaining > size) {
+                       remaining = size - index;
+               }
 
-                       if (i == size) {
-                               d[i - 1] = '\0';
+               for (i = 0; i < remaining; i++) {
+                       if ((d[i] = dtrace_load8(s + index + i)) == '\0')
                                break;
                        }
-               }
+
+               d[i] = '\0';
 
                mstate->dtms_scratch_ptr += size;
                regs[rd] = (uintptr_t)d;
                break;
        }
 
-#if !defined(__APPLE__)
-       case DIF_SUBR_GETMAJOR:
-#ifdef __LP64__
-               regs[rd] = (tupregs[0].dttk_value >> NBITSMINOR64) & MAXMAJ64;
-#else
-               regs[rd] = (tupregs[0].dttk_value >> NBITSMINOR) & MAXMAJ;
-#endif
-               break;
-
-#else  /* __APPLE__ */
        case DIF_SUBR_GETMAJOR:
                regs[rd] = (uintptr_t)major( (dev_t)tupregs[0].dttk_value );
                break;
-#endif /* __APPLE__ */
-
-#if !defined(__APPLE__)
-       case DIF_SUBR_GETMINOR:
-#ifdef __LP64__
-               regs[rd] = tupregs[0].dttk_value & MAXMIN64;
-#else
-               regs[rd] = tupregs[0].dttk_value & MAXMIN;
-#endif
-               break;
 
-#else  /* __APPLE__ */
        case DIF_SUBR_GETMINOR:
                regs[rd] = (uintptr_t)minor( (dev_t)tupregs[0].dttk_value );
                break;
-#endif /* __APPLE__ */
-
-#if !defined(__APPLE__)
-       case DIF_SUBR_DDI_PATHNAME: {
-               /*
-                * This one is a galactic mess.  We are going to roughly
-                * emulate ddi_pathname(), but it's made more complicated
-                * by the fact that we (a) want to include the minor name and
-                * (b) must proceed iteratively instead of recursively.
-                */
-               uintptr_t dest = mstate->dtms_scratch_ptr;
-               uint64_t size = state->dts_options[DTRACEOPT_STRSIZE];
-               char *start = (char *)dest, *end = start + size - 1;
-               uintptr_t daddr = tupregs[0].dttk_value;
-               int64_t minor = (int64_t)tupregs[1].dttk_value;
-               char *s;
-               int i, len, depth = 0;
-
-               if (size == 0 || mstate->dtms_scratch_ptr + size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
-                       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
-                       break;
-               }
-
-               *end = '\0';
-
-               /*
-                * We want to have a name for the minor.  In order to do this,
-                * we need to walk the minor list from the devinfo.  We want
-                * to be sure that we don't infinitely walk a circular list,
-                * so we check for circularity by sending a scout pointer
-                * ahead two elements for every element that we iterate over;
-                * if the list is circular, these will ultimately point to the
-                * same element.  You may recognize this little trick as the
-                * answer to a stupid interview question -- one that always
-                * seems to be asked by those who had to have it laboriously
-                * explained to them, and who can't even concisely describe
-                * the conditions under which one would be forced to resort to
-                * this technique.  Needless to say, those conditions are
-                * found here -- and probably only here.  Is this is the only
-                * use of this infamous trick in shipping, production code?
-                * If it isn't, it probably should be...
-                */
-               if (minor != -1) {
-                       uintptr_t maddr = dtrace_loadptr(daddr +
-                           offsetof(struct dev_info, devi_minor));
-
-                       uintptr_t next = offsetof(struct ddi_minor_data, next);
-                       uintptr_t name = offsetof(struct ddi_minor_data,
-                           d_minor) + offsetof(struct ddi_minor, name);
-                       uintptr_t dev = offsetof(struct ddi_minor_data,
-                           d_minor) + offsetof(struct ddi_minor, dev);
-                       uintptr_t scout;
-
-                       if (maddr != NULL)
-                               scout = dtrace_loadptr(maddr + next);
-
-                       while (maddr != NULL && !(*flags & CPU_DTRACE_FAULT)) {
-                               uint64_t m;
-#ifdef __LP64__
-                               m = dtrace_load64(maddr + dev) & MAXMIN64;
-#else
-                               m = dtrace_load32(maddr + dev) & MAXMIN;
-#endif
-                               if (m != minor) {
-                                       maddr = dtrace_loadptr(maddr + next);
-
-                                       if (scout == NULL)
-                                               continue;
-
-                                       scout = dtrace_loadptr(scout + next);
-
-                                       if (scout == NULL)
-                                               continue;
-
-                                       scout = dtrace_loadptr(scout + next);
-
-                                       if (scout == NULL)
-                                               continue;
-
-                                       if (scout == maddr) {
-                                               *flags |= CPU_DTRACE_ILLOP;
-                                               break;
-                                       }
-
-                                       continue;
-                               }
-
-                               /*
-                                * We have the minor data.  Now we need to
-                                * copy the minor's name into the end of the
-                                * pathname.
-                                */
-                               s = (char *)dtrace_loadptr(maddr + name);
-                               len = dtrace_strlen(s, size);
-
-                               if (*flags & CPU_DTRACE_FAULT)
-                                       break;
-
-                               if (len != 0) {
-                                       if ((end -= (len + 1)) < start)
-                                               break;
-
-                                       *end = ':';
-                               }
-
-                               for (i = 1; i <= len; i++)
-                                       end[i] = dtrace_load8((uintptr_t)s++);
-                               break;
-                       }
-               }
-
-               while (daddr != NULL && !(*flags & CPU_DTRACE_FAULT)) {
-                       ddi_node_state_t devi_state;
-
-                       devi_state = dtrace_load32(daddr +
-                           offsetof(struct dev_info, devi_node_state));
-
-                       if (*flags & CPU_DTRACE_FAULT)
-                               break;
-
-                       if (devi_state >= DS_INITIALIZED) {
-                               s = (char *)dtrace_loadptr(daddr +
-                                   offsetof(struct dev_info, devi_addr));
-                               len = dtrace_strlen(s, size);
-
-                               if (*flags & CPU_DTRACE_FAULT)
-                                       break;
-
-                               if (len != 0) {
-                                       if ((end -= (len + 1)) < start)
-                                               break;
-
-                                       *end = '@';
-                               }
-
-                               for (i = 1; i <= len; i++)
-                                       end[i] = dtrace_load8((uintptr_t)s++);
-                       }
-
-                       /*
-                        * Now for the node name...
-                        */
-                       s = (char *)dtrace_loadptr(daddr +
-                           offsetof(struct dev_info, devi_node_name));
-
-                       daddr = dtrace_loadptr(daddr +
-                           offsetof(struct dev_info, devi_parent));
-
-                       /*
-                        * If our parent is NULL (that is, if we're the root
-                        * node), we're going to use the special path
-                        * "devices".
-                        */
-                       if (daddr == NULL)
-                               s = "devices";
-
-                       len = dtrace_strlen(s, size);
-                       if (*flags & CPU_DTRACE_FAULT)
-                               break;
 
-                       if ((end -= (len + 1)) < start)
-                               break;
-
-                       for (i = 1; i <= len; i++)
-                               end[i] = dtrace_load8((uintptr_t)s++);
-                       *end = '/';
-
-                       if (depth++ > dtrace_devdepth_max) {
-                               *flags |= CPU_DTRACE_ILLOP;
-                               break;
-                       }
-               }
-
-               if (end < start)
-                       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-
-               if (daddr == NULL) {
-                       regs[rd] = (uintptr_t)end;
-                       mstate->dtms_scratch_ptr += size;
-               }
-
-               break;
-       }
-#else
        case DIF_SUBR_DDI_PATHNAME: {
-               /* XXX awaits galactic disentanglement ;-} */
-               regs[rd] = NULL;
+               /* APPLE NOTE: currently unsupported on Darwin */
+               DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
+               regs[rd] = 0;
                break;
        }
-#endif /* __APPLE__ */
 
        case DIF_SUBR_STRJOIN: {
                char *d = (char *)mstate->dtms_scratch_ptr;
                uint64_t size = state->dts_options[DTRACEOPT_STRSIZE];
                uintptr_t s1 = tupregs[0].dttk_value;
                uintptr_t s2 = tupregs[1].dttk_value;
-               int i = 0;
+               uint64_t i = 0;
+
+               if (!dtrace_strcanload(s1, size, mstate, vstate) ||
+                   !dtrace_strcanload(s2, size, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
 
-               if (mstate->dtms_scratch_ptr + size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+               if (!DTRACE_INSCRATCH(mstate, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
+                       regs[rd] = 0;
                        break;
                }
 
                for (;;) {
                        if (i >= size) {
                                DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                               regs[rd] = NULL;
+                               regs[rd] = 0;
                                break;
                        }
 
@@ -3894,7 +4097,7 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                for (;;) {
                        if (i >= size) {
                                DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                               regs[rd] = NULL;
+                               regs[rd] = 0;
                                break;
                        }
 
@@ -3916,10 +4119,9 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                uint64_t size = 22;     /* enough room for 2^64 in decimal */
                char *end = (char *)mstate->dtms_scratch_ptr + size - 1;
 
-               if (mstate->dtms_scratch_ptr + size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+               if (!DTRACE_INSCRATCH(mstate, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
+                       regs[rd] = 0;
                        break;
                }
 
@@ -3937,6 +4139,36 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                break;
        }
 
+       case DIF_SUBR_HTONS:
+       case DIF_SUBR_NTOHS:
+#ifdef _BIG_ENDIAN
+               regs[rd] = (uint16_t)tupregs[0].dttk_value;
+#else
+               regs[rd] = DT_BSWAP_16((uint16_t)tupregs[0].dttk_value);
+#endif
+               break;
+
+
+       case DIF_SUBR_HTONL:
+       case DIF_SUBR_NTOHL:
+#ifdef _BIG_ENDIAN
+               regs[rd] = (uint32_t)tupregs[0].dttk_value;
+#else
+               regs[rd] = DT_BSWAP_32((uint32_t)tupregs[0].dttk_value);
+#endif
+               break;
+
+
+       case DIF_SUBR_HTONLL:
+       case DIF_SUBR_NTOHLL:
+#ifdef _BIG_ENDIAN
+               regs[rd] = (uint64_t)tupregs[0].dttk_value;
+#else
+               regs[rd] = DT_BSWAP_64((uint64_t)tupregs[0].dttk_value);
+#endif
+               break;
+
+
        case DIF_SUBR_DIRNAME:
        case DIF_SUBR_BASENAME: {
                char *dest = (char *)mstate->dtms_scratch_ptr;
@@ -3946,10 +4178,14 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                int lastbase = -1, firstbase = -1, lastdir = -1;
                int start, end;
 
-               if (mstate->dtms_scratch_ptr + size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+               if (!dtrace_canload(src, len + 1, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
+               if (!DTRACE_INSCRATCH(mstate, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
+                       regs[rd] = 0;
                        break;
                }
 
@@ -4055,7 +4291,7 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                        end = lastbase;
                }
 
-               for (i = start, j = 0; i <= end && j < size - 1; i++, j++)
+               for (i = start, j = 0; i <= end && (uint64_t)j < size - 1; i++, j++)
                        dest[j] = dtrace_load8(src + i);
 
                dest[j] = '\0';
@@ -4070,10 +4306,14 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                uintptr_t src = tupregs[0].dttk_value;
                int i = 0, j = 0;
 
-               if (mstate->dtms_scratch_ptr + size >
-                   mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+               if (!dtrace_strcanload(src, size, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
+               if (!DTRACE_INSCRATCH(mstate, size)) {
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                       regs[rd] = NULL;
+                       regs[rd] = 0;
                        break;
                }
 
@@ -4083,7 +4323,7 @@ dtrace_dif_subr(uint_t subr, uint_t rd, uint64_t *regs,
                do {
                        c = dtrace_load8(src + i++);
 next:
-                       if (j + 5 >= size)      /* 5 = strlen("/..c\0") */
+                       if ((uint64_t)(j + 5) >= size)  /* 5 = strlen("/..c\0") */
                                break;
 
                        if (c != '/') {
@@ -4150,46 +4390,322 @@ next:
                                continue;
                        }
 
-                       /*
-                        * This is "/../" or "/..\0".  We need to back up
-                        * our destination pointer until we find a "/".
-                        */
-                       i--;
-                       while (j != 0 && dest[--j] != '/')
-                               continue;
+                       /*
+                        * This is "/../" or "/..\0".  We need to back up
+                        * our destination pointer until we find a "/".
+                        */
+                       i--;
+                       while (j != 0 && dest[--j] != '/')
+                               continue;
+
+                       if (c == '\0')
+                               dest[++j] = '/';
+               } while (c != '\0');
+
+               dest[j] = '\0';
+               regs[rd] = (uintptr_t)dest;
+               mstate->dtms_scratch_ptr += size;
+               break;
+       }
+
+       case DIF_SUBR_INET_NTOA:
+       case DIF_SUBR_INET_NTOA6:
+       case DIF_SUBR_INET_NTOP: {
+               size_t size;
+               int af, argi, i;
+               char *base, *end;
+
+               if (subr == DIF_SUBR_INET_NTOP) {
+                       af = (int)tupregs[0].dttk_value;
+                       argi = 1;
+               } else {
+                       af = subr == DIF_SUBR_INET_NTOA ? AF_INET: AF_INET6;
+                       argi = 0;
+               }
+
+               if (af == AF_INET) {
+#if !defined(__APPLE__)
+                       ipaddr_t ip4;
+#else
+                       uint32_t ip4;
+#endif /* __APPLE__ */
+                       uint8_t *ptr8, val;
+
+                       /*
+                        * Safely load the IPv4 address.
+                        */
+#if !defined(__APPLE__)                        
+                       ip4 = dtrace_load32(tupregs[argi].dttk_value);
+#else
+                       dtrace_bcopy(
+                           (void *)(uintptr_t)tupregs[argi].dttk_value,
+                           (void *)(uintptr_t)&ip4, sizeof (ip4));
+#endif /* __APPLE__ */                 
+                       /*
+                        * Check an IPv4 string will fit in scratch.
+                        */
+#if !defined(__APPLE__)
+                       size = INET_ADDRSTRLEN;
+#else
+                       size = MAX_IPv4_STR_LEN;
+#endif /* __APPLE__ */
+                       if (!DTRACE_INSCRATCH(mstate, size)) {
+                               DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
+                               regs[rd] = 0;
+                               break;
+                       }
+                       base = (char *)mstate->dtms_scratch_ptr;
+                       end = (char *)mstate->dtms_scratch_ptr + size - 1;
+
+                       /*
+                        * Stringify as a dotted decimal quad.
+                        */
+                       *end-- = '\0';
+                       ptr8 = (uint8_t *)&ip4;
+                       for (i = 3; i >= 0; i--) {
+                               val = ptr8[i];
+
+                               if (val == 0) {
+                                       *end-- = '0';
+                               } else {
+                                       for (; val; val /= 10) {
+                                               *end-- = '0' + (val % 10);
+                                       }
+                               }
+
+                               if (i > 0)
+                                       *end-- = '.';
+                       }
+                       ASSERT(end + 1 >= base);
+
+               } else if (af == AF_INET6) {
+#if defined(__APPLE__)
+#define _S6_un __u6_addr
+#define _S6_u8 __u6_addr8
+#endif /* __APPLE__ */
+                       struct in6_addr ip6;
+                       int firstzero, tryzero, numzero, v6end;
+                       uint16_t val;
+                       const char digits[] = "0123456789abcdef";
+
+                       /*
+                        * Stringify using RFC 1884 convention 2 - 16 bit
+                        * hexadecimal values with a zero-run compression.
+                        * Lower case hexadecimal digits are used.
+                        *      eg, fe80::214:4fff:fe0b:76c8.
+                        * The IPv4 embedded form is returned for inet_ntop,
+                        * just the IPv4 string is returned for inet_ntoa6.
+                        */
+
+                       /*
+                        * Safely load the IPv6 address.
+                        */
+                       dtrace_bcopy(
+                           (void *)(uintptr_t)tupregs[argi].dttk_value,
+                           (void *)(uintptr_t)&ip6, sizeof (struct in6_addr));
+
+                       /*
+                        * Check an IPv6 string will fit in scratch.
+                        */
+                       size = INET6_ADDRSTRLEN;
+                       if (!DTRACE_INSCRATCH(mstate, size)) {
+                               DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
+                               regs[rd] = 0;
+                               break;
+                       }
+                       base = (char *)mstate->dtms_scratch_ptr;
+                       end = (char *)mstate->dtms_scratch_ptr + size - 1;
+                       *end-- = '\0';
+
+                       /*
+                        * Find the longest run of 16 bit zero values
+                        * for the single allowed zero compression - "::".
+                        */
+                       firstzero = -1;
+                       tryzero = -1;
+                       numzero = 1;
+                       for (i = 0; i < (int)sizeof (struct in6_addr); i++) {
+                               if (ip6._S6_un._S6_u8[i] == 0 &&
+                                   tryzero == -1 && i % 2 == 0) {
+                                       tryzero = i;
+                                       continue;
+                               }
+
+                               if (tryzero != -1 &&
+                                   (ip6._S6_un._S6_u8[i] != 0 ||
+                                   i == sizeof (struct in6_addr) - 1)) {
+
+                                       if (i - tryzero <= numzero) {
+                                               tryzero = -1;
+                                               continue;
+                                       }
+
+                                       firstzero = tryzero;
+                                       numzero = i - i % 2 - tryzero;
+                                       tryzero = -1;
+
+                                       if (ip6._S6_un._S6_u8[i] == 0 &&
+                                           i == sizeof (struct in6_addr) - 1)
+                                               numzero += 2;
+                               }
+                       }
+                       ASSERT(firstzero + numzero <= (int)sizeof (struct in6_addr));
+
+                       /*
+                        * Check for an IPv4 embedded address.
+                        */
+                       v6end = sizeof (struct in6_addr) - 2;
+                       if (IN6_IS_ADDR_V4MAPPED(&ip6) ||
+                           IN6_IS_ADDR_V4COMPAT(&ip6)) {
+                               for (i = sizeof (struct in6_addr) - 1;
+                                    i >= (int)DTRACE_V4MAPPED_OFFSET; i--) {
+                                       ASSERT(end >= base);
+
+                                       val = ip6._S6_un._S6_u8[i];
+
+                                       if (val == 0) {
+                                               *end-- = '0';
+                                       } else {
+                                               for (; val; val /= 10) {
+                                                       *end-- = '0' + val % 10;
+                                               }
+                                       }
+
+                                       if (i > (int)DTRACE_V4MAPPED_OFFSET)
+                                               *end-- = '.';
+                               }
+
+                               if (subr == DIF_SUBR_INET_NTOA6)
+                                       goto inetout;
+
+                               /*
+                                * Set v6end to skip the IPv4 address that
+                                * we have already stringified.
+                                */
+                               v6end = 10;
+                       }
+
+                       /*
+                        * Build the IPv6 string by working through the
+                        * address in reverse.
+                        */
+                       for (i = v6end; i >= 0; i -= 2) {
+                               ASSERT(end >= base);
+
+                               if (i == firstzero + numzero - 2) {
+                                       *end-- = ':';
+                                       *end-- = ':';
+                                       i -= numzero - 2;
+                                       continue;
+                               }
+
+                               if (i < 14 && i != firstzero - 2)
+                                       *end-- = ':';
+
+                               val = (ip6._S6_un._S6_u8[i] << 8) +
+                                   ip6._S6_un._S6_u8[i + 1];
+
+                               if (val == 0) {
+                                       *end-- = '0';
+                               } else {
+                                       for (; val; val /= 16) {
+                                               *end-- = digits[val % 16];
+                                       }
+                               }
+                       }
+                       ASSERT(end + 1 >= base);
+
+#if defined(__APPLE__)
+#undef _S6_un
+#undef _S6_u8
+#endif /* __APPLE__ */
+               } else {
+                       /*
+                        * The user didn't use AH_INET or AH_INET6.
+                        */
+                       DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
+                       regs[rd] = 0;
+                       break;
+               }
+
+inetout:       regs[rd] = (uintptr_t)end + 1;
+               mstate->dtms_scratch_ptr += size;
+               break;
+       }
+
+       case DIF_SUBR_TOUPPER:
+       case DIF_SUBR_TOLOWER: {
+               uintptr_t src = tupregs[0].dttk_value;
+               char *dest = (char *)mstate->dtms_scratch_ptr;
+               char lower, upper, base, c;
+               uint64_t size = state->dts_options[DTRACEOPT_STRSIZE];
+               size_t len = dtrace_strlen((char*) src, size);
+               size_t i = 0;
+
+               lower = (subr == DIF_SUBR_TOUPPER) ? 'a' : 'A';
+               upper = (subr == DIF_SUBR_TOUPPER) ? 'z' : 'Z';
+               base  = (subr == DIF_SUBR_TOUPPER) ? 'A' : 'a';
+
+               if (!dtrace_canload(src, len + 1, mstate, vstate)) {
+                       regs[rd] = 0;
+                       break;
+               }
+
+               if (!DTRACE_INSCRATCH(mstate, size)) {
+                       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
+                       regs[rd] = 0;
+                       break;
+               }
+
+               for (i = 0; i < size - 1; ++i) {
+                       if ((c = dtrace_load8(src + i)) == '\0')
+                               break;
+                       if (c >= lower && c <= upper)
+                               c = base + (c - lower);
+                       dest[i] = c;
+               }
 
-                       if (c == '\0')
-                               dest[++j] = '/';
-               } while (c != '\0');
+               ASSERT(i < size);
 
-               dest[j] = '\0';
-               regs[rd] = (uintptr_t)dest;
+               dest[i] = '\0';
+               regs[rd] = (uintptr_t) dest;
                mstate->dtms_scratch_ptr += size;
+
                break;
        }
-#ifdef __APPLE__
 
-       /* CHUD callback ('chud(uint64_t, [uint64_t], [uint64_t] ...)') */
-       case DIF_SUBR_CHUD: {
+/*
+ * APPLE NOTE:
+ * CoreProfile callback ('core_profile (uint64_t, [uint64_t], [uint64_t] ...)')
+ */
+       case DIF_SUBR_COREPROFILE: {
                uint64_t selector = tupregs[0].dttk_value;
                uint64_t args[DIF_DTR_NREGS-1] = {0ULL};
                uint32_t ii;
+               uint32_t count = (uint32_t)nargs;
+
+               if (count < 1) {
+                   regs[rd] = KERN_FAILURE;
+                   break;
+               }
+               
+               if(count > DIF_DTR_NREGS)
+                   count = DIF_DTR_NREGS;
 
-               /* copy in any variadic argument list */
-               for(ii = 0; ii < DIF_DTR_NREGS-1; ii++) {
+               /* copy in any variadic argument list, bounded by DIF_DTR_NREGS */
+               for(ii = 0; ii < count-1; ii++) {
                        args[ii] = tupregs[ii+1].dttk_value;
                }
 
                kern_return_t ret = 
-                       chudxnu_dtrace_callback(selector, args, DIF_DTR_NREGS-1);
+                       chudxnu_dtrace_callback(selector, args, count-1);
                if(KERN_SUCCESS != ret) {
                        /* error */
                }
+
+               regs[rd] = ret;
                break;
        }
-
-#endif /* __APPLE__ */
-
        }
 }
 
@@ -4212,11 +4728,7 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
        dtrace_dstate_t *dstate = &vstate->dtvs_dynvars;
        dtrace_difv_t *v;
        volatile uint16_t *flags = &cpu_core[CPU->cpu_id].cpuc_dtrace_flags;
-#if !defined(__APPLE__)
-       volatile uintptr_t *illval = &cpu_core[CPU->cpu_id].cpuc_dtrace_illval;
-#else
        volatile uint64_t *illval = &cpu_core[CPU->cpu_id].cpuc_dtrace_illval;
-#endif /* __APPLE__ */
 
        dtrace_key_t tupregs[DIF_DTR_NREGS + 2]; /* +2 for thread and id */
        uint64_t regs[DIF_DIR_NREGS];
@@ -4224,11 +4736,17 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
 
        uint8_t cc_n = 0, cc_z = 0, cc_v = 0, cc_c = 0;
        int64_t cc_r;
-       uint_t pc = 0, id, opc;
+       uint_t pc = 0, id, opc = 0;
        uint8_t ttop = 0;
        dif_instr_t instr;
        uint_t r1, r2, rd;
 
+       /*
+        * We stash the current DIF object into the machine state: we need it
+        * for subsequent access checking.
+        */
+       mstate->dtms_difo = difo;
+
        regs[DIF_REG_R0] = 0;           /* %r0 is fixed at zero */
 
        while (pc < textlen && !(*flags & CPU_DTRACE_FAULT)) {
@@ -4432,6 +4950,12 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                case DIF_OP_LDX:
                        regs[rd] = dtrace_load64(regs[r1]);
                        break;
+/*
+ * Darwin 32-bit kernel may fetch from 64-bit user.
+ * Do not cast regs to uintptr_t
+ * DIF_OP_ULDSB,DIF_OP_ULDSH, DIF_OP_ULDSW, DIF_OP_ULDUB
+ * DIF_OP_ULDUH, DIF_OP_ULDUW, DIF_OP_ULDX
+ */
                case DIF_OP_ULDSB:
                        regs[rd] = (int8_t)
                            dtrace_fuword8(regs[r1]);
@@ -4462,6 +4986,7 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                        break;
                case DIF_OP_RET:
                        rval = regs[rd];
+                       pc = textlen;
                        break;
                case DIF_OP_NOP:
                        break;
@@ -4472,15 +4997,25 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                        regs[rd] = (uint64_t)(uintptr_t)
                            (strtab + DIF_INSTR_STRING(instr));
                        break;
-               case DIF_OP_SCMP:
-                       cc_r = dtrace_strncmp((char *)(uintptr_t)regs[r1],
-                           (char *)(uintptr_t)regs[r2],
-                           state->dts_options[DTRACEOPT_STRSIZE]);
+               case DIF_OP_SCMP: {
+                       size_t sz = state->dts_options[DTRACEOPT_STRSIZE];
+                       uintptr_t s1 = regs[r1];
+                       uintptr_t s2 = regs[r2];
+
+                       if (s1 != 0 &&
+                           !dtrace_strcanload(s1, sz, mstate, vstate))
+                               break;
+                       if (s2 != 0 &&
+                           !dtrace_strcanload(s2, sz, mstate, vstate))
+                               break;
+
+                       cc_r = dtrace_strncmp((char *)s1, (char *)s2, sz);
 
                        cc_n = cc_r < 0;
                        cc_z = cc_r == 0;
                        cc_v = cc_c = 0;
                        break;
+               }
                case DIF_OP_LDGA:
                        regs[rd] = dtrace_dif_variable(mstate, state,
                            r1, regs[r2]);
@@ -4509,7 +5044,7 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                                         * then this is to be treated as a
                                         * reference to a NULL variable.
                                         */
-                                       regs[rd] = NULL;
+                                       regs[rd] = 0;
                                } else {
                                        regs[rd] = a + sizeof (uint64_t);
                                }
@@ -4533,16 +5068,20 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                        if (v->dtdv_type.dtdt_flags & DIF_TF_BYREF) {
                                uintptr_t a = (uintptr_t)svar->dtsv_data;
 
-                               ASSERT(a != NULL);
+                               ASSERT(a != 0);
                                ASSERT(svar->dtsv_size != 0);
 
-                               if (regs[rd] == NULL) {
+                               if (regs[rd] == 0) {
                                        *(uint8_t *)a = UINT8_MAX;
                                        break;
                                } else {
                                        *(uint8_t *)a = 0;
                                        a += sizeof (uint64_t);
                                }
+                               if (!dtrace_vcanload(
+                                   (void *)(uintptr_t)regs[rd], &v->dtdv_type,
+                                   mstate, vstate))
+                                       break;
 
                                dtrace_vcopy((void *)(uintptr_t)regs[rd],
                                    (void *)a, &v->dtdv_type);
@@ -4574,9 +5113,8 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
 
                        id -= DIF_VAR_OTHER_UBASE;
 
-                       ASSERT(id < vstate->dtvs_nlocals);
+                       ASSERT(id < (uint_t)vstate->dtvs_nlocals);
                        ASSERT(vstate->dtvs_locals != NULL);
-
                        svar = vstate->dtvs_locals[id];
                        ASSERT(svar != NULL);
                        v = &svar->dtsv_var;
@@ -4595,7 +5133,7 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                                         * then this is to be treated as a
                                         * reference to a NULL variable.
                                         */
-                                       regs[rd] = NULL;
+                                       regs[rd] = 0;
                                } else {
                                        regs[rd] = a + sizeof (uint64_t);
                                }
@@ -4613,8 +5151,7 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
 
                        ASSERT(id >= DIF_VAR_OTHER_UBASE);
                        id -= DIF_VAR_OTHER_UBASE;
-                       ASSERT(id < vstate->dtvs_nlocals);
-
+                       ASSERT(id < (uint_t)vstate->dtvs_nlocals);
                        ASSERT(vstate->dtvs_locals != NULL);
                        svar = vstate->dtvs_locals[id];
                        ASSERT(svar != NULL);
@@ -4628,7 +5165,7 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                                ASSERT(svar->dtsv_size == (int)NCPU * sz);
                                a += CPU->cpu_id * sz;
 
-                               if (regs[rd] == NULL) {
+                               if (regs[rd] == 0) {
                                        *(uint8_t *)a = UINT8_MAX;
                                        break;
                                } else {
@@ -4636,6 +5173,11 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                                        a += sizeof (uint64_t);
                                }
 
+                               if (!dtrace_vcanload(
+                                   (void *)(uintptr_t)regs[rd], &v->dtdv_type,
+                                   mstate, vstate))
+                                       break;
+
                                dtrace_vcopy((void *)(uintptr_t)regs[rd],
                                    (void *)a, &v->dtdv_type);
                                break;
@@ -4662,7 +5204,8 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                        key[1].dttk_size = 0;
 
                        dvar = dtrace_dynvar(dstate, 2, key,
-                           sizeof (uint64_t), DTRACE_DYNVAR_NOALLOC);
+                           sizeof (uint64_t), DTRACE_DYNVAR_NOALLOC,
+                           mstate, vstate);
 
                        if (dvar == NULL) {
                                regs[rd] = 0;
@@ -4697,23 +5240,23 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                            v->dtdv_type.dtdt_size > sizeof (uint64_t) ?
                            v->dtdv_type.dtdt_size : sizeof (uint64_t),
                            regs[rd] ? DTRACE_DYNVAR_ALLOC :
-                           DTRACE_DYNVAR_DEALLOC);
+                           DTRACE_DYNVAR_DEALLOC, mstate, vstate);
 
                        /*
                         * Given that we're storing to thread-local data,
                         * we need to flush our predicate cache.
                         */
-#if !defined(__APPLE__)
-                       curthread->t_predcache = NULL;
-#else
                        dtrace_set_thread_predcache(current_thread(), 0);
-#endif /* __APPLE__ */
-
 
                        if (dvar == NULL)
                                break;
 
                        if (v->dtdv_type.dtdt_flags & DIF_TF_BYREF) {
+                               if (!dtrace_vcanload(
+                                   (void *)(uintptr_t)regs[rd],
+                                   &v->dtdv_type, mstate, vstate))
+                                       break;
+
                                dtrace_vcopy((void *)(uintptr_t)regs[rd],
                                    dvar->dtdv_data, &v->dtdv_type);
                        } else {
@@ -4801,7 +5344,7 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                        dvar = dtrace_dynvar(dstate, nkeys, key,
                            v->dtdv_type.dtdt_size > sizeof (uint64_t) ?
                            v->dtdv_type.dtdt_size : sizeof (uint64_t),
-                           DTRACE_DYNVAR_NOALLOC);
+                           DTRACE_DYNVAR_NOALLOC, mstate, vstate);
 
                        if (dvar == NULL) {
                                regs[rd] = 0;
@@ -4842,12 +5385,17 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                            v->dtdv_type.dtdt_size > sizeof (uint64_t) ?
                            v->dtdv_type.dtdt_size : sizeof (uint64_t),
                            regs[rd] ? DTRACE_DYNVAR_ALLOC :
-                           DTRACE_DYNVAR_DEALLOC);
+                           DTRACE_DYNVAR_DEALLOC, mstate, vstate);
 
                        if (dvar == NULL)
                                break;
 
                        if (v->dtdv_type.dtdt_flags & DIF_TF_BYREF) {
+                               if (!dtrace_vcanload(
+                                   (void *)(uintptr_t)regs[rd], &v->dtdv_type,
+                                   mstate, vstate))
+                                       break;
+
                                dtrace_vcopy((void *)(uintptr_t)regs[rd],
                                    dvar->dtdv_data, &v->dtdv_type);
                        } else {
@@ -4861,17 +5409,21 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                        uintptr_t ptr = P2ROUNDUP(mstate->dtms_scratch_ptr, 8);
                        size_t size = ptr - mstate->dtms_scratch_ptr + regs[r1];
 
-                       if (mstate->dtms_scratch_ptr + size >
-                           mstate->dtms_scratch_base +
-                           mstate->dtms_scratch_size) {
+                       /*
+                        * Rounding up the user allocation size could have
+                        * overflowed large, bogus allocations (like -1ULL) to
+                        * 0.
+                        */
+                       if (size < regs[r1] ||
+                           !DTRACE_INSCRATCH(mstate, size)) {
                                DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
-                               regs[rd] = NULL;
-                       } else {
-                               dtrace_bzero((void *)
-                                   mstate->dtms_scratch_ptr, size);
+                               regs[rd] = 0;
+                               break;
+                       }
+
+                       dtrace_bzero((void *) mstate->dtms_scratch_ptr, size);
                                mstate->dtms_scratch_ptr += size;
                                regs[rd] = ptr;
-                       }
                        break;
                }
 
@@ -4883,6 +5435,9 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                                break;
                        }
 
+                       if (!dtrace_canload(regs[r1], regs[r2], mstate, vstate))
+                               break;
+
                        dtrace_bcopy((void *)(uintptr_t)regs[r1],
                            (void *)(uintptr_t)regs[rd], (size_t)regs[r2]);
                        break;
@@ -4930,11 +5485,12 @@ dtrace_dif_emulate(dtrace_difo_t *difo, dtrace_mstate_t *mstate,
                                *illval = regs[rd];
                                break;
                        }
-#if !defined(__APPLE__)
-                       if (regs[rd] & 7) {
-#else
-                       if (regs[rd] & 3) { /* Darwin kmem_zalloc() called from dtrace_difo_init() is 4-byte aligned. */
-#endif /* __APPLE__ */
+
+                       /*
+                       * Darwin kmem_zalloc() called from
+                       * dtrace_difo_init() is 4-byte aligned.
+                       */
+                       if (regs[rd] & 3) {
                                *flags |= CPU_DTRACE_BADALIGN;
                                *illval = regs[rd];
                                break;
@@ -4959,8 +5515,8 @@ dtrace_action_breakpoint(dtrace_ecb_t *ecb)
        dtrace_probe_t *probe = ecb->dte_probe;
        dtrace_provider_t *prov = probe->dtpr_provider;
        char c[DTRACE_FULLNAMELEN + 80], *str;
-       char *msg = "dtrace: breakpoint action at probe ";
-       char *ecbmsg = " (ecb ";
+       const char *msg = "dtrace: breakpoint action at probe ";
+       const char *ecbmsg = " (ecb ";
        uintptr_t mask = (0xf << (sizeof (uintptr_t) * NBBY / 4));
        uintptr_t val = (uintptr_t)ecb;
        int shift = (sizeof (uintptr_t) * NBBY) - 4, i = 0;
@@ -5031,27 +5587,23 @@ dtrace_action_panic(dtrace_ecb_t *ecb)
        if (dtrace_panicked != NULL)
                return;
 
-#if !defined(__APPLE__)
-       if (dtrace_casptr(&dtrace_panicked, NULL, curthread) != NULL)
-               return;
-#else
        if (dtrace_casptr(&dtrace_panicked, NULL, current_thread()) != NULL)
                return;
-#endif /* __APPLE__ */
 
        /*
         * We won the right to panic.  (We want to be sure that only one
         * thread calls panic() from dtrace_probe(), and that panic() is
         * called exactly once.)
         */
-       dtrace_panic("dtrace: panic action at probe %s:%s:%s:%s (ecb %p)",
+       panic("dtrace: panic action at probe %s:%s:%s:%s (ecb %p)",
            probe->dtpr_provider->dtpv_name, probe->dtpr_mod,
            probe->dtpr_func, probe->dtpr_name, (void *)ecb);
 
-#if defined(__APPLE__)
-       /* Mac OS X debug feature -- can return from panic() */
+       /*
+        * APPLE NOTE: this was for an old Mac OS X debug feature
+        * allowing a return from panic().  Revisit someday.
+        */
        dtrace_panicked = NULL;
-#endif /* __APPLE__ */
 }
 
 static void
@@ -5065,24 +5617,17 @@ dtrace_action_raise(uint64_t sig)
                return;
        }
 
-#if !defined(__APPLE__)
        /*
         * raise() has a queue depth of 1 -- we ignore all subsequent
         * invocations of the raise() action.
         */
-       if (curthread->t_dtrace_sig == 0)
-               curthread->t_dtrace_sig = (uint8_t)sig;
 
-       curthread->t_sig_check = 1;
-       aston(curthread);
-#else
        uthread_t uthread = (uthread_t)get_bsdthread_info(current_thread());
 
        if (uthread && uthread->t_dtrace_sig == 0) {
                uthread->t_dtrace_sig = sig;
-               psignal(current_proc(), (int)sig);
+               act_set_astbsd(current_thread());
        }
-#endif /* __APPLE__ */
 }
 
 static void
@@ -5091,15 +5636,47 @@ dtrace_action_stop(void)
        if (dtrace_destructive_disallow)
                return;
 
-#if !defined(__APPLE__)
-       if (!curthread->t_dtrace_stop) {
-               curthread->t_dtrace_stop = 1;
-               curthread->t_sig_check = 1;
-               aston(curthread);
+        uthread_t uthread = (uthread_t)get_bsdthread_info(current_thread());
+       if (uthread) {
+               /*
+                * The currently running process will be set to task_suspend
+                * when it next leaves the kernel.
+               */
+               uthread->t_dtrace_stop = 1;
+               act_set_astbsd(current_thread());
+       }
+}
+
+
+/*
+ * APPLE NOTE: pidresume works in conjunction with the dtrace stop action.
+ * Both activate only when the currently running process next leaves the
+ * kernel.
+ */
+static void
+dtrace_action_pidresume(uint64_t pid)
+{
+       if (dtrace_destructive_disallow)
+               return;
+
+       if (kauth_cred_issuser(kauth_cred_get()) == 0) {
+               DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);           
+               return;
+       }
+        uthread_t uthread = (uthread_t)get_bsdthread_info(current_thread());
+
+       /*
+        * When the currently running process leaves the kernel, it attempts to
+        * task_resume the process (denoted by pid), if that pid appears to have
+        * been stopped by dtrace_action_stop().
+        * The currently running process has a pidresume() queue depth of 1 --
+        * subsequent invocations of the pidresume() action are ignored.
+        */     
+
+       if (pid != 0 && uthread && uthread->t_dtrace_resumepid == 0) {
+               uthread->t_dtrace_resumepid = pid;
+               act_set_astbsd(current_thread());
        }
-#else
-       psignal(current_proc(), SIGSTOP);
-#endif /* __APPLE__ */
 }
 
 static void
@@ -5107,7 +5684,7 @@ dtrace_action_chill(dtrace_mstate_t *mstate, hrtime_t val)
 {
        hrtime_t now;
        volatile uint16_t *flags;
-       cpu_t *cpu = CPU;
+       dtrace_cpu_t *cpu = CPU;
 
        if (dtrace_destructive_disallow)
                return;
@@ -5173,8 +5750,7 @@ dtrace_action_ustack(dtrace_mstate_t *mstate, dtrace_state_t *state,
        size = (uintptr_t)fps - mstate->dtms_scratch_ptr +
            (nframes * sizeof (uint64_t));
 
-       if (mstate->dtms_scratch_ptr + size >
-           mstate->dtms_scratch_base + mstate->dtms_scratch_size) {
+       if (!DTRACE_INSCRATCH(mstate, (uintptr_t)size)) {
                /*
                 * Not enough room for our frame pointers -- need to indicate
                 * that we ran out of scratch space.
@@ -5266,15 +5842,9 @@ out:
  * is the function called by the provider to fire a probe -- from which all
  * subsequent probe-context DTrace activity emanates.
  */
-#if !defined(__APPLE__)
-void
-dtrace_probe(dtrace_id_t id, uintptr_t arg0, uintptr_t arg1,
-    uintptr_t arg2, uintptr_t arg3, uintptr_t arg4)
-#else
 static void
 __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
     uint64_t arg2, uint64_t arg3, uint64_t arg4)
-#endif /* __APPLE__ */
 {
        processorid_t cpuid;
        dtrace_icookie_t cookie;
@@ -5288,28 +5858,13 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
        volatile uint16_t *flags;
        hrtime_t now;
 
-#if !defined(__APPLE__)
-       /*
-        * Kick out immediately if this CPU is still being born (in which case
-        * curthread will be set to -1)
-        */
-       if ((uintptr_t)curthread & 1)
-               return;
-#else
-#endif /* __APPLE__ */
-
        cookie = dtrace_interrupt_disable();
        probe = dtrace_probes[id - 1];
        cpuid = CPU->cpu_id;
        onintr = CPU_ON_INTR(CPU);
 
-#if !defined(__APPLE__)
-       if (!onintr && probe->dtpr_predcache != DTRACE_CACHEIDNONE &&
-           probe->dtpr_predcache == curthread->t_predcache) {
-#else
        if (!onintr && probe->dtpr_predcache != DTRACE_CACHEIDNONE &&
            probe->dtpr_predcache == dtrace_get_thread_predcache(current_thread())) {
-#endif /* __APPLE__ */
                /*
                 * We have hit in the predicate cache; we know that
                 * this predicate would evaluate to be false.
@@ -5333,6 +5888,11 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
        if (vtime && curthread->t_dtrace_start)
                curthread->t_dtrace_vtime += now - curthread->t_dtrace_start;
 #else
+       /*
+        * APPLE NOTE:  The time spent entering DTrace and arriving
+        * to this point, is attributed to the current thread.
+        * Instead it should accrue to DTrace.  FIXME
+        */
        vtime = dtrace_vtime_references != 0;
 
        if (vtime)
@@ -5354,14 +5914,14 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
        now = dtrace_gethrtime(); /* must not precede dtrace_calc_thread_recent_vtime() call! */
 #endif /* __APPLE__ */
 
-#if defined(__APPLE__)
        /*
-        * A provider may call dtrace_probe_error() in lieu of dtrace_probe() in some circumstances.
-        * See, e.g. fasttrap_isa.c. However the provider has no access to ECB context, so passes
-        * NULL through "arg0" and the probe_id of the ovedrriden probe as arg1. Detect that here
-        * and cons up a viable state (from the probe_id).
+        * APPLE NOTE: A provider may call dtrace_probe_error() in lieu of
+        * dtrace_probe() in some circumstances.   See, e.g. fasttrap_isa.c.
+        * However the provider has no access to ECB context, so passes
+        * 0 through "arg0" and the probe_id of the overridden probe as arg1.
+        * Detect that here and cons up a viable state (from the probe_id).
         */
-       if (dtrace_probeid_error == id && NULL == arg0) {
+       if (dtrace_probeid_error == id && 0 == arg0) {
                dtrace_id_t ftp_id = (dtrace_id_t)arg1;
                dtrace_probe_t *ftp_probe = dtrace_probes[ftp_id - 1];
                dtrace_ecb_t *ftp_ecb = ftp_probe->dtpr_ecb;
@@ -5377,9 +5937,10 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                        ftp_state->dts_arg_error_illval = -1; /* arg5 */
                }
        }
-#endif /* __APPLE__ */
 
+       mstate.dtms_difo = NULL;
        mstate.dtms_probe = probe;
+       mstate.dtms_strtok = 0;
        mstate.dtms_arg[0] = arg0;
        mstate.dtms_arg[1] = arg1;
        mstate.dtms_arg[2] = arg2;
@@ -5395,6 +5956,7 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                dtrace_buffer_t *aggbuf = &state->dts_aggbuffer[cpuid];
                dtrace_vstate_t *vstate = &state->dts_vstate;
                dtrace_provider_t *prov = probe->dtpr_provider;
+               uint64_t tracememsize = 0;
                int committed = 0;
                caddr_t tomax;
 
@@ -5483,25 +6045,26 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                                cred_t *s_cr =
                                    ecb->dte_state->dts_cred.dcr_cred;
                                proc_t *proc;
+#pragma unused(proc) /* __APPLE__ */
 
                                ASSERT(s_cr != NULL);
 
-#if !defined(__APPLE__)
-                               if ((cr = CRED()) == NULL ||
-#else
+                       /*
+                        * XXX this is hackish, but so is setting a variable
+                        * XXX in a McCarthy OR...
+                        */
                                if ((cr = dtrace_CRED()) == NULL ||
-#endif /* __APPLE__ */
-                                   s_cr->cr_uid != cr->cr_uid ||
-                                   s_cr->cr_uid != cr->cr_ruid ||
-                                   s_cr->cr_uid != cr->cr_suid ||
-                                   s_cr->cr_gid != cr->cr_gid ||
-                                   s_cr->cr_gid != cr->cr_rgid ||
-                                   s_cr->cr_gid != cr->cr_sgid ||
+                                   posix_cred_get(s_cr)->cr_uid != posix_cred_get(cr)->cr_uid ||
+                                   posix_cred_get(s_cr)->cr_uid != posix_cred_get(cr)->cr_ruid ||
+                                   posix_cred_get(s_cr)->cr_uid != posix_cred_get(cr)->cr_suid ||
+                                   posix_cred_get(s_cr)->cr_gid != posix_cred_get(cr)->cr_gid ||
+                                   posix_cred_get(s_cr)->cr_gid != posix_cred_get(cr)->cr_rgid ||
+                                   posix_cred_get(s_cr)->cr_gid != posix_cred_get(cr)->cr_sgid ||
 #if !defined(__APPLE__)
                                    (proc = ttoproc(curthread)) == NULL ||
                                    (proc->p_flag & SNOCD))
 #else
-                                       1) /* Darwin omits "No Core Dump" flag. */
+                                       1) /* APPLE NOTE: Darwin omits "No Core Dump" flag */
 #endif /* __APPLE__ */
                                        continue;
                        }
@@ -5510,14 +6073,17 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                                cred_t *cr;
                                cred_t *s_cr =
                                    ecb->dte_state->dts_cred.dcr_cred;
+#pragma unused(cr, s_cr) /* __APPLE__ */
 
                                ASSERT(s_cr != NULL);
 
-#if !defined(__APPLE__) /* Darwin doesn't do zones. */
+#if !defined(__APPLE__)
                                if ((cr = CRED()) == NULL ||
                                    s_cr->cr_zone->zone_id !=
                                    cr->cr_zone->zone_id)
                                        continue;
+#else
+                               /* APPLE NOTE: Darwin doesn't do zones. */
 #endif /* __APPLE__ */
                        }
                }
@@ -5559,6 +6125,11 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                mstate.dtms_epid = ecb->dte_epid;
                mstate.dtms_present |= DTRACE_MSTATE_EPID;
 
+               if (state->dts_cred.dcr_visible & DTRACE_CRV_KERNEL)
+                       mstate.dtms_access = DTRACE_ACCESS_KERNEL;
+               else
+                       mstate.dtms_access = 0;
+
                if (pred != NULL) {
                        dtrace_difo_t *dp = pred->dtp_difo;
                        int rval;
@@ -5573,11 +6144,8 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                                         * Update the predicate cache...
                                         */
                                        ASSERT(cid == pred->dtp_cacheid);
-#if !defined(__APPLE__)
-                                       curthread->t_predcache = cid;
-#else
+
                                        dtrace_set_thread_predcache(current_thread(), cid);
-#endif /* __APPLE__ */
                                }
 
                                continue;
@@ -5642,8 +6210,7 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                                dtrace_getpcstack((pc_t *)(tomax + valoffs),
                                    size / sizeof (pc_t), probe->dtpr_aframes,
                                    DTRACE_ANCHORED(probe) ? NULL :
-                                   (uint32_t *)arg0);
-
+                                 (uint32_t *)(uintptr_t)arg0);
                                continue;
 
                        case DTRACEACT_JSTACK:
@@ -5738,6 +6305,11 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                                        dtrace_action_raise(val);
                                continue;
 
+                       case DTRACEACT_PIDRESUME:   /* __APPLE__ */
+                               if (dtrace_priv_proc_destructive(state))
+                                       dtrace_action_pidresume(val);
+                               continue;
+
                        case DTRACEACT_COMMIT:
                                ASSERT(!committed);
 
@@ -5761,6 +6333,12 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                        case DTRACEACT_PRINTA:
                        case DTRACEACT_SYSTEM:
                        case DTRACEACT_FREOPEN:
+                       case DTRACEACT_APPLEBINARY:   /* __APPLE__ */
+                       case DTRACEACT_TRACEMEM:
+                               break;
+
+                       case DTRACEACT_TRACEMEM_DYNSIZE:
+                               tracememsize = val;
                                break;
 
                        case DTRACEACT_SYM:
@@ -5769,23 +6347,6 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                                        continue;
                                break;
 
-#if !defined(__APPLE__)
-                       case DTRACEACT_USYM:
-                       case DTRACEACT_UMOD:
-                       case DTRACEACT_UADDR: {
-                               struct pid *pid = curthread->t_procp->p_pidp;
-
-                               if (!dtrace_priv_proc(state))
-                                       continue;
-
-                               DTRACE_STORE(uint64_t, tomax,
-                                   valoffs, (uint64_t)pid->pid_id);
-                               DTRACE_STORE(uint64_t, tomax,
-                                   valoffs + sizeof (uint64_t), val);
-
-                               continue;
-                       }
-#else
                        case DTRACEACT_USYM:
                        case DTRACEACT_UMOD:
                        case DTRACEACT_UADDR: {
@@ -5793,13 +6354,12 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                                        continue;
 
                                DTRACE_STORE(uint64_t, tomax,
-                                   valoffs, (uint64_t)proc_selfpid());
+                                   valoffs, (uint64_t)dtrace_proc_selfpid());
                                DTRACE_STORE(uint64_t, tomax,
                                    valoffs + sizeof (uint64_t), val);
 
                                continue;
                        }
-#endif /* __APPLE__ */
 
                        case DTRACEACT_EXIT: {
                                /*
@@ -5842,6 +6402,17 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                        if (dp->dtdo_rtype.dtdt_flags & DIF_TF_BYREF) {
                                uintptr_t end = valoffs + size;
 
+                               if (tracememsize != 0 &&
+                                    valoffs + tracememsize < end)
+                               {
+                                        end = valoffs + tracememsize;
+                                        tracememsize = 0;
+                                }
+
+                               if (!dtrace_vcanload((void *)(uintptr_t)val,
+                                   &dp->dtdo_rtype, &mstate, vstate))
+                                       continue;
+
                                /*
                                 * If this is a string, we're going to only
                                 * load until we find the zero byte -- after
@@ -5928,13 +6499,14 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                                 * time to prevent it from being accumulated
                                 * into t_dtrace_vtime.
                                 */
-#if !defined(__APPLE__)
-                               curthread->t_dtrace_start = 0;
-#else
-                               /* Set the sign bit on t_dtrace_tracing to suspend accumulation to it. */
+
+                               /*                                 
+                                * Darwin sets the sign bit on t_dtrace_tracing
+                                * to suspend accumulation to it.
+                                */
                                dtrace_set_thread_tracing(current_thread(), 
-                                                       (1ULL<<63) | dtrace_get_thread_tracing(current_thread()));
-#endif /* __APPLE__ */
+                                   (1ULL<<63) | dtrace_get_thread_tracing(current_thread()));
+
                        }
 
                        /*
@@ -5961,10 +6533,8 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                        buf->dtb_offset = offs + ecb->dte_size;
        }
 
-#if !defined(__APPLE__)
-       if (vtime)
-               curthread->t_dtrace_start = dtrace_gethrtime();
-#else
+       /* FIXME: On Darwin the time spent leaving DTrace from this point to the rti is attributed
+          to the current thread. Instead it should accrue to DTrace. */
        if (vtime) {
                thread_t thread = current_thread();
                int64_t t = dtrace_get_thread_tracing(thread);
@@ -5977,29 +6547,38 @@ __dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
                        dtrace_set_thread_tracing(thread, (~(1ULL<<63)) & t); 
                }
        }
-#endif /* __APPLE__ */
 
        dtrace_interrupt_enable(cookie);
 }
 
-#if defined(__APPLE__)
-/* Don't allow a thread to re-enter dtrace_probe() */
+/*
+ * APPLE NOTE:  Don't allow a thread to re-enter dtrace_probe().
+ * This could occur if a probe is encountered on some function in the
+ * transitive closure of the call to dtrace_probe().
+ * Solaris has some strong guarantees that this won't happen.
+ * The Darwin implementation is not so mature as to make those guarantees.
+ * Hence, the introduction of __dtrace_probe() on xnu.
+ */
+
 void
 dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
     uint64_t arg2, uint64_t arg3, uint64_t arg4)
 {
        thread_t thread = current_thread();
-
+       disable_preemption();
        if (id == dtrace_probeid_error) {
                __dtrace_probe(id, arg0, arg1, arg2, arg3, arg4);
-               dtrace_getfp(); /* Defeat tail-call optimization of __dtrace_probe() */
+               dtrace_getipl(); /* Defeat tail-call optimization of __dtrace_probe() */
        } else if (!dtrace_get_thread_reentering(thread)) {
                dtrace_set_thread_reentering(thread, TRUE);
                __dtrace_probe(id, arg0, arg1, arg2, arg3, arg4);
                dtrace_set_thread_reentering(thread, FALSE);
        }
+#if DEBUG
+       else __dtrace_probe(dtrace_probeid_error, 0, id, 1, -1, DTRACEFLT_UNKNOWN);
+#endif
+       enable_preemption();
 }
-#endif /* __APPLE__ */
 
 /*
  * DTrace Probe Hashing Functions
@@ -6013,7 +6592,7 @@ dtrace_probe(dtrace_id_t id, uint64_t arg0, uint64_t arg1,
  * specified.)
  */
 static uint_t
-dtrace_hash_str(char *p)
+dtrace_hash_str(const char *p)
 {
        unsigned int g;
        uint_t hval = 0;
@@ -6045,11 +6624,16 @@ dtrace_hash_create(uintptr_t stroffs, uintptr_t nextoffs, uintptr_t prevoffs)
        return (hash);
 }
 
-#if !defined(__APPLE__) /* Quiet compiler warning */
+/*
+ * APPLE NOTE: dtrace_hash_destroy is not used.
+ * It is called by dtrace_detach which is not
+ * currently implemented.  Revisit someday.
+ */
+#if !defined(__APPLE__)
 static void
 dtrace_hash_destroy(dtrace_hash_t *hash)
 {
-#ifdef DEBUG
+#if DEBUG
        int i;
 
        for (i = 0; i < hash->dth_size; i++)
@@ -6159,7 +6743,7 @@ dtrace_hash_collisions(dtrace_hash_t *hash, dtrace_probe_t *template)
                        return (bucket->dthb_len);
        }
 
-       return (NULL);
+       return (0);
 }
 
 static void
@@ -6231,14 +6815,16 @@ dtrace_badattr(const dtrace_attribute_t *a)
 /*
  * Return a duplicate copy of a string.  If the specified string is NULL,
  * this function returns a zero-length string.
+ * APPLE NOTE: Darwin employs size bounded string operation.
  */
 static char *
 dtrace_strdup(const char *str)
 {
-       char *new = kmem_zalloc((str != NULL ? strlen(str) : 0) + 1, KM_SLEEP);
+       size_t bufsize = (str != NULL ? strlen(str) : 0) + 1;
+       char *new = kmem_zalloc(bufsize, KM_SLEEP);
 
        if (str != NULL)
-               (void) strcpy(new, str);
+               (void) strlcpy(new, str, bufsize);
 
        return (new);
 }
@@ -6300,16 +6886,12 @@ dtrace_cred2priv(cred_t *cr, uint32_t *privp, uid_t *uidp, zoneid_t *zoneidp)
 static void
 dtrace_errdebug(const char *str)
 {
-       int hval = dtrace_hash_str((char *)str) % DTRACE_ERRHASHSZ;
+       int hval = dtrace_hash_str(str) % DTRACE_ERRHASHSZ;
        int occupied = 0;
 
        lck_mtx_lock(&dtrace_errlock);
        dtrace_errlast = str;
-#if !defined(__APPLE__)
-       dtrace_errthread = curthread;
-#else
-       dtrace_errthread = current_thread();
-#endif /* __APPLE__ */
+       dtrace_errthread = (kthread_t *)current_thread();
 
        while (occupied++ < DTRACE_ERRHASHSZ) {
                if (dtrace_errhash[hval].dter_msg == str) {
@@ -6536,14 +7118,17 @@ top:
 static int
 dtrace_match_string(const char *s, const char *p, int depth)
 {
-       return (s != NULL && strcmp(s, p) == 0);
+#pragma unused(depth) /* __APPLE__ */
+
+       /* APPLE NOTE: Darwin employs size bounded string operation. */
+       return (s != NULL && strncmp(s, p, strlen(s) + 1) == 0);
 }
 
 /*ARGSUSED*/
 static int
 dtrace_match_nul(const char *s, const char *p, int depth)
 {
-#pragma unused(s,p,depth)
+#pragma unused(s, p, depth) /* __APPLE__ */
        return (1); /* always match the empty pattern */
 }
 
@@ -6551,7 +7136,7 @@ dtrace_match_nul(const char *s, const char *p, int depth)
 static int
 dtrace_match_nonzero(const char *s, const char *p, int depth)
 {
-#pragma unused(p,depth)
+#pragma unused(p, depth) /* __APPLE__ */
        return (s != NULL && s[0] != '\0');
 }
 
@@ -6561,7 +7146,7 @@ dtrace_match(const dtrace_probekey_t *pkp, uint32_t priv, uid_t uid,
 {
        dtrace_probe_t template, *probe;
        dtrace_hash_t *hash = NULL;
-       int len, best = INT_MAX, nmatched = 0;
+       int len, rc, best = INT_MAX, nmatched = 0;
        dtrace_id_t i;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
@@ -6573,15 +7158,16 @@ dtrace_match(const dtrace_probekey_t *pkp, uint32_t priv, uid_t uid,
        if (pkp->dtpk_id != DTRACE_IDNONE) {
                if ((probe = dtrace_probe_lookup_id(pkp->dtpk_id)) != NULL &&
                    dtrace_match_probe(probe, pkp, priv, uid, zoneid) > 0) {
-                       (void) (*matched)(probe, arg);
+                       if ((*matched)(probe, arg) == DTRACE_MATCH_FAIL)
+                               return (DTRACE_MATCH_FAIL);
                        nmatched++;
                }
                return (nmatched);
        }
 
-       template.dtpr_mod = (char *)pkp->dtpk_mod;
-       template.dtpr_func = (char *)pkp->dtpk_func;
-       template.dtpr_name = (char *)pkp->dtpk_name;
+       template.dtpr_mod =  (char *)(uintptr_t)pkp->dtpk_mod;
+       template.dtpr_func = (char *)(uintptr_t)pkp->dtpk_func;
+       template.dtpr_name = (char *)(uintptr_t)pkp->dtpk_name;
 
        /*
         * We want to find the most distinct of the module name, function
@@ -6612,7 +7198,7 @@ dtrace_match(const dtrace_probekey_t *pkp, uint32_t priv, uid_t uid,
         * invoke our callback for each one that matches our input probe key.
         */
        if (hash == NULL) {
-               for (i = 0; i < dtrace_nprobes; i++) {
+               for (i = 0; i < (dtrace_id_t)dtrace_nprobes; i++) {
                        if ((probe = dtrace_probes[i]) == NULL ||
                            dtrace_match_probe(probe, pkp, priv, uid,
                            zoneid) <= 0)
@@ -6620,8 +7206,11 @@ dtrace_match(const dtrace_probekey_t *pkp, uint32_t priv, uid_t uid,
 
                        nmatched++;
 
-                       if ((*matched)(probe, arg) != DTRACE_MATCH_NEXT)
-                               break;
+                       if ((rc = (*matched)(probe, arg)) != DTRACE_MATCH_NEXT) {
+                              if (rc == DTRACE_MATCH_FAIL)
+                                       return (DTRACE_MATCH_FAIL);
+                              break;
+                       }
                }
 
                return (nmatched);
@@ -6640,8 +7229,11 @@ dtrace_match(const dtrace_probekey_t *pkp, uint32_t priv, uid_t uid,
 
                nmatched++;
 
-               if ((*matched)(probe, arg) != DTRACE_MATCH_NEXT)
-                       break;
+               if ((rc = (*matched)(probe, arg)) != DTRACE_MATCH_NEXT) {
+                   if (rc == DTRACE_MATCH_FAIL)
+                       return (DTRACE_MATCH_FAIL);
+                   break;
+               }
        }
 
        return (nmatched);
@@ -6765,8 +7357,13 @@ dtrace_register(const char *name, const dtrace_pattr_t *pap, uint32_t priv,
        }
 
        provider = kmem_zalloc(sizeof (dtrace_provider_t), KM_SLEEP);
-       provider->dtpv_name = kmem_alloc(strlen(name) + 1, KM_SLEEP);
-       (void) strcpy(provider->dtpv_name, name);
+
+       /* APPLE NOTE: Darwin employs size bounded string operation. */
+       {
+       size_t bufsize = strlen(name) + 1;
+       provider->dtpv_name = kmem_alloc(bufsize, KM_SLEEP);
+       (void) strlcpy(provider->dtpv_name, name, bufsize);
+       }
 
        provider->dtpv_attr = *pap;
        provider->dtpv_priv.dtpp_flags = priv;
@@ -6861,7 +7458,7 @@ dtrace_unregister(dtrace_provider_id_t id)
        dtrace_probe_t *probe, *first = NULL;
 
        if (old->dtpv_pops.dtps_enable ==
-           (void (*)(void *, dtrace_id_t, void *))dtrace_nullop) {
+           (int (*)(void *, dtrace_id_t, void *))dtrace_enable_nullop) {
                /*
                 * If DTrace itself is the provider, we're called with locks
                 * already held.
@@ -6870,7 +7467,6 @@ dtrace_unregister(dtrace_provider_id_t id)
                ASSERT(dtrace_devi != NULL);
                lck_mtx_assert(&dtrace_provider_lock, LCK_MTX_ASSERT_OWNED);
                lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
-
                self = 1;
 
                if (dtrace_provider->dtpv_next != NULL) {
@@ -6904,16 +7500,7 @@ dtrace_unregister(dtrace_provider_id_t id)
        /*
         * Attempt to destroy the probes associated with this provider.
         */
-       for (i = 0; i < dtrace_nprobes; i++) {
-               if ((probe = dtrace_probes[i]) == NULL)
-                       continue;
-
-               if (probe->dtpr_provider != old)
-                       continue;
-
-               if (probe->dtpr_ecb == NULL)
-                       continue;
-
+       if (old->dtpv_ecb_count!=0) {
                /*
                 * We have at least one ECB; we can't remove this provider.
                 */
@@ -6929,7 +7516,7 @@ dtrace_unregister(dtrace_provider_id_t id)
         * All of the probes for this provider are disabled; we can safely
         * remove all of them from their hash chains and from the probe array.
         */
-       for (i = 0; i < dtrace_nprobes; i++) {
+       for (i = 0; i < dtrace_nprobes && old->dtpv_probe_count!=0; i++) {
                if ((probe = dtrace_probes[i]) == NULL)
                        continue;
 
@@ -6937,6 +7524,7 @@ dtrace_unregister(dtrace_provider_id_t id)
                        continue;
 
                dtrace_probes[i] = NULL;
+               old->dtpv_probe_count--;
 
                dtrace_hash_remove(dtrace_bymod, probe);
                dtrace_hash_remove(dtrace_byfunc, probe);
@@ -6967,11 +7555,7 @@ dtrace_unregister(dtrace_provider_id_t id)
                kmem_free(probe->dtpr_func, strlen(probe->dtpr_func) + 1);
                kmem_free(probe->dtpr_name, strlen(probe->dtpr_name) + 1);
                vmem_free(dtrace_arena, (void *)(uintptr_t)(probe->dtpr_id), 1);
-#if !defined(__APPLE__)
-               kmem_free(probe, sizeof (dtrace_probe_t));
-#else
                zfree(dtrace_probe_t_zone, probe);
-#endif
        }
 
        if ((prev = dtrace_provider) == old) {
@@ -7012,7 +7596,7 @@ dtrace_invalidate(dtrace_provider_id_t id)
        dtrace_provider_t *pvp = (dtrace_provider_t *)id;
 
        ASSERT(pvp->dtpv_pops.dtps_enable !=
-           (void (*)(void *, dtrace_id_t, void *))dtrace_nullop);
+           (int (*)(void *, dtrace_id_t, void *))dtrace_enable_nullop);
 
        lck_mtx_lock(&dtrace_provider_lock);
        lck_mtx_lock(&dtrace_lock);
@@ -7053,7 +7637,7 @@ dtrace_condense(dtrace_provider_id_t id)
         * Make sure this isn't the dtrace provider itself.
         */
        ASSERT(prov->dtpv_pops.dtps_enable !=
-           (void (*)(void *, dtrace_id_t, void *))dtrace_nullop);
+         (int (*)(void *, dtrace_id_t, void *))dtrace_enable_nullop);
 
        lck_mtx_lock(&dtrace_provider_lock);
        lck_mtx_lock(&dtrace_lock);
@@ -7072,6 +7656,7 @@ dtrace_condense(dtrace_provider_id_t id)
                        continue;
 
                dtrace_probes[i] = NULL;
+               prov->dtpv_probe_count--;
 
                dtrace_hash_remove(dtrace_bymod, probe);
                dtrace_hash_remove(dtrace_byfunc, probe);
@@ -7082,11 +7667,7 @@ dtrace_condense(dtrace_provider_id_t id)
                kmem_free(probe->dtpr_mod, strlen(probe->dtpr_mod) + 1);
                kmem_free(probe->dtpr_func, strlen(probe->dtpr_func) + 1);
                kmem_free(probe->dtpr_name, strlen(probe->dtpr_name) + 1);
-#if !defined(__APPLE__)
-               kmem_free(probe, sizeof (dtrace_probe_t));
-#else
                zfree(dtrace_probe_t_zone, probe);
-#endif
                vmem_free(dtrace_arena, (void *)((uintptr_t)i + 1), 1);
        }
 
@@ -7125,12 +7706,9 @@ dtrace_probe_create(dtrace_provider_id_t prov, const char *mod,
 
        id = (dtrace_id_t)(uintptr_t)vmem_alloc(dtrace_arena, 1,
            VM_BESTFIT | VM_SLEEP);
-#if !defined(__APPLE__)
-       probe = kmem_zalloc(sizeof (dtrace_probe_t), KM_SLEEP);
-#else
+
        probe = zalloc(dtrace_probe_t_zone);
        bzero(probe, sizeof (dtrace_probe_t));
-#endif
 
        probe->dtpr_id = id;
        probe->dtpr_gen = dtrace_probegen++;
@@ -7145,7 +7723,7 @@ dtrace_probe_create(dtrace_provider_id_t prov, const char *mod,
        dtrace_hash_add(dtrace_byfunc, probe);
        dtrace_hash_add(dtrace_byname, probe);
 
-       if (id - 1 >= dtrace_nprobes) {
+       if (id - 1 >= (dtrace_id_t)dtrace_nprobes) {
                size_t osize = dtrace_nprobes * sizeof (dtrace_probe_t *);
                size_t nsize = osize << 1;
 
@@ -7178,11 +7756,12 @@ dtrace_probe_create(dtrace_provider_id_t prov, const char *mod,
                        dtrace_nprobes <<= 1;
                }
 
-               ASSERT(id - 1 < dtrace_nprobes);
+               ASSERT(id - 1 < (dtrace_id_t)dtrace_nprobes);
        }
 
        ASSERT(dtrace_probes[id - 1] == NULL);
        dtrace_probes[id - 1] = probe;
+       provider->dtpv_probe_count++;   
 
        if (provider != dtrace_provider)
                lck_mtx_unlock(&dtrace_lock);
@@ -7195,7 +7774,7 @@ dtrace_probe_lookup_id(dtrace_id_t id)
 {
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
 
-       if (id == 0 || id > dtrace_nprobes)
+       if (id == 0 || id > (dtrace_id_t)dtrace_nprobes)
                return (NULL);
 
        return (dtrace_probes[id - 1]);
@@ -7269,6 +7848,7 @@ dtrace_probe_description(const dtrace_probe_t *prp, dtrace_probedesc_t *pdp)
        bzero(pdp, sizeof (dtrace_probedesc_t));
        pdp->dtpd_id = prp->dtpr_id;
 
+       /* APPLE NOTE: Darwin employs size bounded string operation. */
        (void) strlcpy(pdp->dtpd_provider,
            prp->dtpr_provider->dtpv_name, DTRACE_PROVNAMELEN);
 
@@ -7304,14 +7884,13 @@ dtrace_probe_provide(dtrace_probedesc_t *desc, dtrace_provider_t *prv)
                all = 1;
                prv = dtrace_provider;
        }
-
+                
        do {
                /*
                 * First, call the blanket provide operation.
                 */
                prv->dtpv_pops.dtps_provide(prv->dtpv_arg, desc);
-
-#if !defined(__APPLE__)
+               
                /*
                 * Now call the per-module provide operation.  We will grab
                 * mod_lock to prevent the list from being modified.  Note
@@ -7319,37 +7898,14 @@ dtrace_probe_provide(dtrace_probedesc_t *desc, dtrace_provider_t *prv)
                 * (mod_busy can only be changed with mod_lock held.)
                 */
                lck_mtx_lock(&mod_lock);
-
-               ctl = &modules;
-               do {
-                       if (ctl->mod_busy || ctl->mod_mp == NULL)
-                               continue;
-
-                       prv->dtpv_pops.dtps_provide_module(prv->dtpv_arg, ctl);
-
-               } while ((ctl = ctl->mod_next) != &modules);
-
-               lck_mtx_unlock(&mod_lock);
-#else
-#if 0 /* FIXME: Workaround for PR_4643546 */
-               simple_lock(&kmod_lock);
                
-               kmod_info_t *ktl = kmod;
-               while (ktl) {
-                       prv->dtpv_pops.dtps_provide_module(prv->dtpv_arg, ktl);
-                       ktl = ktl->next;
+               ctl = dtrace_modctl_list;
+               while (ctl) {
+                       prv->dtpv_pops.dtps_provide_module(prv->dtpv_arg, ctl);
+                       ctl = ctl->mod_next;
                }
                
-               simple_unlock(&kmod_lock);
-#else
-               /*
-                * Don't bother to iterate over the kmod list. At present only fbt
-                * offers a provide_module in its dtpv_pops, and then it ignores the
-                * module anyway.
-                */
-               prv->dtpv_pops.dtps_provide_module(prv->dtpv_arg, NULL);
-#endif
-#endif /* __APPLE__ */
+               lck_mtx_unlock(&mod_lock);
        } while (all && (prv = prv->dtpv_next) != NULL);
 }
 
@@ -7516,15 +8072,15 @@ dtrace_helper_provide_one(dof_helper_t *dhp, dof_sec_t *sec, pid_t pid)
                dhpb.dthpb_mod = dhp->dofhp_mod;
                dhpb.dthpb_func = strtab + probe->dofpr_func;
                dhpb.dthpb_name = strtab + probe->dofpr_name;
-#if defined(__APPLE__)
-               dhpb.dthpb_base = dhp->dofhp_addr;
-#else
+#if !defined(__APPLE__)
                dhpb.dthpb_base = probe->dofpr_addr;
+#else
+               dhpb.dthpb_base = dhp->dofhp_addr; /* FIXME: James, why? */
 #endif
-               dhpb.dthpb_offs = off + probe->dofpr_offidx;
+               dhpb.dthpb_offs = (int32_t *)(off + probe->dofpr_offidx);
                dhpb.dthpb_noffs = probe->dofpr_noffs;
                if (enoff != NULL) {
-                       dhpb.dthpb_enoffs = enoff + probe->dofpr_enoffidx;
+                       dhpb.dthpb_enoffs = (int32_t *)(enoff + probe->dofpr_enoffidx);
                        dhpb.dthpb_nenoffs = probe->dofpr_nenoffs;
                } else {
                        dhpb.dthpb_enoffs = NULL;
@@ -7545,7 +8101,7 @@ dtrace_helper_provide(dof_helper_t *dhp, pid_t pid)
 {
        uintptr_t daddr = (uintptr_t)dhp->dofhp_dof;
        dof_hdr_t *dof = (dof_hdr_t *)daddr;
-       int i;
+       uint32_t i;
 
        lck_mtx_assert(&dtrace_meta_lock, LCK_MTX_ASSERT_OWNED);
 
@@ -7602,7 +8158,7 @@ dtrace_helper_provider_remove(dof_helper_t *dhp, pid_t pid)
 {
        uintptr_t daddr = (uintptr_t)dhp->dofhp_dof;
        dof_hdr_t *dof = (dof_hdr_t *)daddr;
-       int i;
+       uint32_t i;
 
        lck_mtx_assert(&dtrace_meta_lock, LCK_MTX_ASSERT_OWNED);
 
@@ -7629,7 +8185,7 @@ dtrace_meta_register(const char *name, const dtrace_mops_t *mops, void *arg,
 {
        dtrace_meta_t *meta;
        dtrace_helpers_t *help, *next;
-       int i;
+       uint_t i;
 
        *idp = DTRACE_METAPROVNONE;
 
@@ -7654,8 +8210,14 @@ dtrace_meta_register(const char *name, const dtrace_mops_t *mops, void *arg,
 
        meta = kmem_zalloc(sizeof (dtrace_meta_t), KM_SLEEP);
        meta->dtm_mops = *mops;
-       meta->dtm_name = kmem_alloc(strlen(name) + 1, KM_SLEEP);
-       (void) strcpy(meta->dtm_name, name);
+
+       /* APPLE NOTE: Darwin employs size bounded string operation. */
+       {
+       size_t bufsize = strlen(name) + 1;
+       meta->dtm_name = kmem_alloc(bufsize, KM_SLEEP);
+       (void) strlcpy(meta->dtm_name, name, bufsize);
+       }
+
        meta->dtm_arg = arg;
 
        lck_mtx_lock(&dtrace_meta_lock);
@@ -7771,13 +8333,15 @@ static int
 dtrace_difo_validate(dtrace_difo_t *dp, dtrace_vstate_t *vstate, uint_t nregs,
     cred_t *cr)
 {
-       int err = 0, i;
+       int err = 0;
+       uint_t i;
+
        int (*efunc)(uint_t pc, const char *, ...) = dtrace_difo_err;
-       int kcheck;
+       int kcheckload;
        uint_t pc;
 
-       kcheck = cr == NULL ||
-           PRIV_POLICY_ONLY(cr, PRIV_DTRACE_KERNEL, B_FALSE) == 0;
+       kcheckload = cr == NULL ||
+           (vstate->dtvs_state->dts_cred.dcr_visible & DTRACE_CRV_KERNEL) == 0;
 
        dp->dtdo_destructive = 0;
 
@@ -7845,7 +8409,7 @@ dtrace_difo_validate(dtrace_difo_t *dp, dtrace_vstate_t *vstate, uint_t nregs,
                                err += efunc(pc, "invalid register %u\n", rd);
                        if (rd == 0)
                                err += efunc(pc, "cannot write to %r0\n");
-                       if (kcheck)
+                       if (kcheckload)
                                dp->dtdo_buf[pc] = DIF_INSTR_LOAD(op +
                                    DIF_OP_RLDSB - DIF_OP_LDSB, r1, rd);
                        break;
@@ -8049,14 +8613,15 @@ dtrace_difo_validate(dtrace_difo_t *dp, dtrace_vstate_t *vstate, uint_t nregs,
                        break;
 
                default:
-                       err += efunc(dp->dtdo_len - 1, "bad return size");
+                       err += efunc(dp->dtdo_len - 1, "bad return size\n");
                }
        }
 
        for (i = 0; i < dp->dtdo_varlen && err == 0; i++) {
                dtrace_difv_t *v = &dp->dtdo_vartab[i], *existing = NULL;
                dtrace_diftype_t *vt, *et;
-               uint_t id, ndx;
+               uint_t id;
+               int ndx;
 
                if (v->dtdv_scope != DIFV_SCOPE_GLOBAL &&
                    v->dtdv_scope != DIFV_SCOPE_THREAD &&
@@ -8281,13 +8846,22 @@ dtrace_difo_validate_helper(dtrace_difo_t *dp)
                            subr == DIF_SUBR_COPYINTO ||
                            subr == DIF_SUBR_COPYINSTR ||
                            subr == DIF_SUBR_INDEX ||
+                           subr == DIF_SUBR_INET_NTOA ||
+                           subr == DIF_SUBR_INET_NTOA6 ||
+                           subr == DIF_SUBR_INET_NTOP ||
                            subr == DIF_SUBR_LLTOSTR ||
                            subr == DIF_SUBR_RINDEX ||
                            subr == DIF_SUBR_STRCHR ||
                            subr == DIF_SUBR_STRJOIN ||
                            subr == DIF_SUBR_STRRCHR ||
                            subr == DIF_SUBR_STRSTR ||
-                               subr == DIF_SUBR_CHUD)
+                           subr == DIF_SUBR_COREPROFILE ||
+                           subr == DIF_SUBR_HTONS ||
+                           subr == DIF_SUBR_HTONL ||
+                           subr == DIF_SUBR_HTONLL ||
+                           subr == DIF_SUBR_NTOHS ||
+                           subr == DIF_SUBR_NTOHL ||
+                           subr == DIF_SUBR_NTOHLL)
                                break;
 
                        err += efunc(pc, "invalid subr %u\n", subr);
@@ -8309,7 +8883,7 @@ dtrace_difo_validate_helper(dtrace_difo_t *dp)
 static int
 dtrace_difo_cacheable(dtrace_difo_t *dp)
 {
-       int i;
+       uint_t i;
 
        if (dp == NULL)
                return (0);
@@ -8354,7 +8928,7 @@ dtrace_difo_cacheable(dtrace_difo_t *dp)
 static void
 dtrace_difo_hold(dtrace_difo_t *dp)
 {
-       int i;
+       uint_t i;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
 
@@ -8386,7 +8960,7 @@ dtrace_difo_hold(dtrace_difo_t *dp)
 static void
 dtrace_difo_chunksize(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
 {
-       uint64_t sval;
+       uint64_t sval = 0;
        dtrace_key_t tupregs[DIF_DTR_NREGS + 2]; /* +2 for thread and id */
        const dif_instr_t *text = dp->dtdo_buf;
        uint_t pc, srd = 0;
@@ -8521,18 +9095,19 @@ dtrace_difo_chunksize(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
 static void
 dtrace_difo_init(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
 {
-       int i, oldsvars, osz, nsz, otlocals, ntlocals;
-       uint_t id;
+       int oldsvars, osz, nsz, otlocals, ntlocals;
+       uint_t i, id;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
        ASSERT(dp->dtdo_buf != NULL && dp->dtdo_len != 0);
 
        for (i = 0; i < dp->dtdo_varlen; i++) {
                dtrace_difv_t *v = &dp->dtdo_vartab[i];
-               dtrace_statvar_t *svar, ***svarp;
+               dtrace_statvar_t *svar;
+               dtrace_statvar_t ***svarp = NULL;
                size_t dsize = 0;
                uint8_t scope = v->dtdv_scope;
-               int *np;
+               int *np = (int *)NULL;
 
                if ((id = v->dtdv_id) < DIF_VAR_OTHER_UBASE)
                        continue;
@@ -8541,7 +9116,7 @@ dtrace_difo_init(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
 
                switch (scope) {
                case DIFV_SCOPE_THREAD:
-                       while (id >= (otlocals = vstate->dtvs_ntlocals)) {
+                       while (id >= (uint_t)(otlocals = vstate->dtvs_ntlocals)) {
                                dtrace_difv_t *tlocals;
 
                                if ((ntlocals = (otlocals << 1)) == 0)
@@ -8591,7 +9166,7 @@ dtrace_difo_init(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
                        ASSERT(0);
                }
 
-               while (id >= (oldsvars = *np)) {
+               while (id >= (uint_t)(oldsvars = *np)) {
                        dtrace_statvar_t **statics;
                        int newsvars, oldsize, newsize;
 
@@ -8678,16 +9253,17 @@ dtrace_difo_duplicate(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
 static void
 dtrace_difo_destroy(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
 {
-       int i;
+       uint_t i;
 
        ASSERT(dp->dtdo_refcnt == 0);
 
        for (i = 0; i < dp->dtdo_varlen; i++) {
                dtrace_difv_t *v = &dp->dtdo_vartab[i];
-               dtrace_statvar_t *svar, **svarp;
+               dtrace_statvar_t *svar;
+               dtrace_statvar_t **svarp = NULL;
                uint_t id;
                uint8_t scope = v->dtdv_scope;
-               int *np;
+               int *np = NULL;
 
                switch (scope) {
                case DIFV_SCOPE_THREAD:
@@ -8711,7 +9287,8 @@ dtrace_difo_destroy(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
                        continue;
 
                id -= DIF_VAR_OTHER_UBASE;
-               ASSERT(id < *np);
+               
+               ASSERT(id < (uint_t)*np);
 
                svar = svarp[id];
                ASSERT(svar != NULL);
@@ -8721,7 +9298,7 @@ dtrace_difo_destroy(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
                        continue;
 
                if (svar->dtsv_size != 0) {
-                       ASSERT(svar->dtsv_data != NULL);
+                       ASSERT(svar->dtsv_data != 0);
                        kmem_free((void *)(uintptr_t)svar->dtsv_data,
                            svar->dtsv_size);
                }
@@ -8741,7 +9318,7 @@ dtrace_difo_destroy(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
 static void
 dtrace_difo_release(dtrace_difo_t *dp, dtrace_vstate_t *vstate)
 {
-       int i;
+       uint_t i;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
        ASSERT(dp->dtdo_refcnt != 0);
@@ -8897,6 +9474,7 @@ static void
 dtrace_predicate_release(dtrace_predicate_t *pred, dtrace_vstate_t *vstate)
 {
        dtrace_difo_t *dp = pred->dtp_difo;
+#pragma unused(dp) /* __APPLE__ */
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
        ASSERT(dp != NULL && dp->dtdo_refcnt != 0);
@@ -8917,8 +9495,8 @@ dtrace_actdesc_create(dtrace_actkind_t kind, uint32_t ntuple,
 {
        dtrace_actdesc_t *act;
 
-/*     ASSERT(!DTRACEACT_ISPRINTFLIKE(kind) || (arg != NULL &&
-  arg >= KERNELBASE) || (arg == NULL && kind == DTRACEACT_PRINTA));*/
+       ASSERT(!DTRACEACT_ISPRINTFLIKE(kind) || (arg != 0 &&
+           arg >= KERNELBASE) || (arg == 0 && kind == DTRACEACT_PRINTA));
 
        act = kmem_zalloc(sizeof (dtrace_actdesc_t), KM_SLEEP);
        act->dtad_kind = kind;
@@ -8954,8 +9532,8 @@ dtrace_actdesc_release(dtrace_actdesc_t *act, dtrace_vstate_t *vstate)
        if (DTRACEACT_ISPRINTFLIKE(kind)) {
                char *str = (char *)(uintptr_t)act->dtad_arg;
 
-/*             ASSERT((str != NULL && (uintptr_t)str >= KERNELBASE) ||
-  (str == NULL && act->dtad_kind == DTRACEACT_PRINTA));*/
+               ASSERT((str != NULL && (uintptr_t)str >= KERNELBASE) ||
+                   (str == NULL && act->dtad_kind == DTRACEACT_PRINTA));
 
                if (str != NULL)
                        kmem_free(str, strlen(str) + 1);
@@ -8988,11 +9566,11 @@ dtrace_ecb_add(dtrace_state_t *state, dtrace_probe_t *probe)
 
        epid = state->dts_epid++;
 
-       if (epid - 1 >= state->dts_necbs) {
+       if (epid - 1 >= (dtrace_epid_t)state->dts_necbs) {
                dtrace_ecb_t **oecbs = state->dts_ecbs, **ecbs;
                int necbs = state->dts_necbs << 1;
 
-               ASSERT(epid == state->dts_necbs + 1);
+               ASSERT(epid == (dtrace_epid_t)state->dts_necbs + 1);
 
                if (necbs == 0) {
                        ASSERT(oecbs == NULL);
@@ -9034,7 +9612,7 @@ dtrace_ecb_add(dtrace_state_t *state, dtrace_probe_t *probe)
        return (ecb);
 }
 
-static void
+static int
 dtrace_ecb_enable(dtrace_ecb_t *ecb)
 {
        dtrace_probe_t *probe = ecb->dte_probe;
@@ -9047,9 +9625,10 @@ dtrace_ecb_enable(dtrace_ecb_t *ecb)
                /*
                 * This is the NULL probe -- there's nothing to do.
                 */
-               return;
+           return(0);
        }
 
+       probe->dtpr_provider->dtpv_ecb_count++;
        if (probe->dtpr_ecb == NULL) {
                dtrace_provider_t *prov = probe->dtpr_provider;
 
@@ -9061,8 +9640,8 @@ dtrace_ecb_enable(dtrace_ecb_t *ecb)
                if (ecb->dte_predicate != NULL)
                        probe->dtpr_predcache = ecb->dte_predicate->dtp_cacheid;
 
-               prov->dtpv_pops.dtps_enable(prov->dtpv_arg,
-                   probe->dtpr_id, probe->dtpr_arg);
+               return (prov->dtpv_pops.dtps_enable(prov->dtpv_arg,
+                    probe->dtpr_id, probe->dtpr_arg));
        } else {
                /*
                 * This probe is already active.  Swing the last pointer to
@@ -9075,6 +9654,7 @@ dtrace_ecb_enable(dtrace_ecb_t *ecb)
                probe->dtpr_predcache = 0;
 
                dtrace_sync();
+               return(0);
        }
 }
 
@@ -9217,11 +9797,12 @@ dtrace_ecb_aggregation_create(dtrace_ecb_t *ecb, dtrace_actdesc_t *desc)
 
        switch (desc->dtad_kind) {
        case DTRACEAGG_MIN:
-               agg->dtag_initial = UINT64_MAX;
+               agg->dtag_initial = INT64_MAX;
                agg->dtag_aggregate = dtrace_aggregate_min;
                break;
 
        case DTRACEAGG_MAX:
+               agg->dtag_initial = INT64_MIN;
                agg->dtag_aggregate = dtrace_aggregate_max;
                break;
 
@@ -9249,11 +9830,44 @@ dtrace_ecb_aggregation_create(dtrace_ecb_t *ecb, dtrace_actdesc_t *desc)
                break;
        }
 
+       case DTRACEAGG_LLQUANTIZE: {
+               uint16_t factor = DTRACE_LLQUANTIZE_FACTOR(desc->dtad_arg);
+               uint16_t low    = DTRACE_LLQUANTIZE_LOW(desc->dtad_arg);
+               uint16_t high   = DTRACE_LLQUANTIZE_HIGH(desc->dtad_arg);
+               uint16_t nsteps = DTRACE_LLQUANTIZE_NSTEP(desc->dtad_arg);
+               int64_t v;
+
+               agg->dtag_initial = desc->dtad_arg;
+               agg->dtag_aggregate = dtrace_aggregate_llquantize;
+
+               if (factor < 2 || low >= high || nsteps < factor)
+                       goto err;
+
+               /*
+                * Now check that the number of steps evenly divides a power
+                * of the factor.  (This assures both integer bucket size and
+                * linearity within each magnitude.)
+                */
+               for (v = factor; v < nsteps; v *= factor)
+                       continue;
+
+               if ((v % nsteps) || (nsteps % factor))
+                       goto err;
+
+               size = (dtrace_aggregate_llquantize_bucket(factor, low, high, nsteps, INT64_MAX) + 2) * sizeof (uint64_t);
+               break;
+  }
+
        case DTRACEAGG_AVG:
                agg->dtag_aggregate = dtrace_aggregate_avg;
                size = sizeof (uint64_t) * 2;
                break;
 
+       case DTRACEAGG_STDDEV:
+               agg->dtag_aggregate = dtrace_aggregate_stddev;
+               size = sizeof (uint64_t) * 4;
+               break;
+
        case DTRACEAGG_SUM:
                agg->dtag_aggregate = dtrace_aggregate_sum;
                break;
@@ -9312,13 +9926,13 @@ success:
        aggid = (dtrace_aggid_t)(uintptr_t)vmem_alloc(state->dts_aggid_arena, 1,
            VM_BESTFIT | VM_SLEEP);
 
-       if (aggid - 1 >= state->dts_naggregations) {
+       if (aggid - 1 >= (dtrace_aggid_t)state->dts_naggregations) {
                dtrace_aggregation_t **oaggs = state->dts_aggregations;
                dtrace_aggregation_t **aggs;
                int naggs = state->dts_naggregations << 1;
                int onaggs = state->dts_naggregations;
 
-               ASSERT(aggid == state->dts_naggregations + 1);
+               ASSERT(aggid == (dtrace_aggid_t)state->dts_naggregations + 1);
 
                if (naggs == 0) {
                        ASSERT(oaggs == NULL);
@@ -9376,7 +9990,8 @@ dtrace_ecb_action_add(dtrace_ecb_t *ecb, dtrace_actdesc_t *desc)
        uint16_t format = 0;
        dtrace_recdesc_t *rec;
        dtrace_state_t *state = ecb->dte_state;
-       dtrace_optval_t *opt = state->dts_options, nframes, strsize;
+       dtrace_optval_t *opt = state->dts_options;
+       dtrace_optval_t nframes=0, strsize;
        uint64_t arg = desc->dtad_arg;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
@@ -9417,12 +10032,12 @@ dtrace_ecb_action_add(dtrace_ecb_t *ecb, dtrace_actdesc_t *desc)
                         * We know that our arg is a string -- turn it into a
                         * format.
                         */
-                       if (arg == NULL) {
+                       if (arg == 0) {
                                ASSERT(desc->dtad_kind == DTRACEACT_PRINTA);
                                format = 0;
                        } else {
-                               ASSERT(arg != NULL);
-                               /* ASSERT(arg > KERNELBASE); */
+                               ASSERT(arg != 0);
+                               ASSERT(arg > KERNELBASE);
                                format = dtrace_format_add(state,
                                    (char *)(uintptr_t)arg);
                        }
@@ -9430,6 +10045,9 @@ dtrace_ecb_action_add(dtrace_ecb_t *ecb, dtrace_actdesc_t *desc)
                        /*FALLTHROUGH*/
                case DTRACEACT_LIBACT:
                case DTRACEACT_DIFEXPR:
+               case DTRACEACT_TRACEMEM:
+               case DTRACEACT_TRACEMEM_DYNSIZE:
+               case DTRACEACT_APPLEBINARY:     /* __APPLE__ */
                        if (dp == NULL)
                                return (EINVAL);
 
@@ -9516,6 +10134,7 @@ dtrace_ecb_action_add(dtrace_ecb_t *ecb, dtrace_actdesc_t *desc)
                case DTRACEACT_CHILL:
                case DTRACEACT_DISCARD:
                case DTRACEACT_RAISE:
+               case DTRACEACT_PIDRESUME:       /* __APPLE__ */
                        if (dp == NULL)
                                return (EINVAL);
                        break;
@@ -9681,6 +10300,7 @@ dtrace_ecb_disable(dtrace_ecb_t *ecb)
                probe->dtpr_ecb_last = prev;
        }
 
+       probe->dtpr_provider->dtpv_ecb_count--;
        /*
         * The ECB has been disconnected from the probe; now sync to assure
         * that all CPUs have seen the change before returning.
@@ -9852,7 +10472,9 @@ dtrace_ecb_create_enable(dtrace_probe_t *probe, void *arg)
        if ((ecb = dtrace_ecb_create(state, probe, enab)) == NULL)
                return (DTRACE_MATCH_DONE);
 
-       dtrace_ecb_enable(ecb);
+       if (dtrace_ecb_enable(ecb) < 0)
+               return (DTRACE_MATCH_FAIL);
+       
        return (DTRACE_MATCH_NEXT);
 }
 
@@ -9860,10 +10482,11 @@ static dtrace_ecb_t *
 dtrace_epid2ecb(dtrace_state_t *state, dtrace_epid_t id)
 {
        dtrace_ecb_t *ecb;
+#pragma unused(ecb) /* __APPLE__ */
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
 
-       if (id == 0 || id > state->dts_necbs)
+       if (id == 0 || id > (dtrace_epid_t)state->dts_necbs)
                return (NULL);
 
        ASSERT(state->dts_necbs > 0 && state->dts_ecbs != NULL);
@@ -9876,10 +10499,11 @@ static dtrace_aggregation_t *
 dtrace_aggid2agg(dtrace_state_t *state, dtrace_aggid_t id)
 {
        dtrace_aggregation_t *agg;
+#pragma unused(agg) /* __APPLE__ */
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
 
-       if (id == 0 || id > state->dts_naggregations)
+       if (id == 0 || id > (dtrace_aggid_t)state->dts_naggregations)
                return (NULL);
 
        ASSERT(state->dts_naggregations > 0 && state->dts_aggregations != NULL);
@@ -9955,25 +10579,32 @@ dtrace_buffer_activate(dtrace_state_t *state)
        dtrace_interrupt_enable(cookie);
 }
 
+static int
+dtrace_buffer_canalloc(size_t size)
+{
+       if (size > (UINT64_MAX - dtrace_buffer_memory_inuse))
+               return (B_FALSE);
+       if ((size + dtrace_buffer_memory_inuse) > dtrace_buffer_memory_maxsize)
+               return (B_FALSE);
+
+       return (B_TRUE);
+}
+
 static int
 dtrace_buffer_alloc(dtrace_buffer_t *bufs, size_t size, int flags,
     processorid_t cpu)
 {
-       cpu_t *cp;
+       dtrace_cpu_t *cp;
        dtrace_buffer_t *buf;
+       size_t size_before_alloc = dtrace_buffer_memory_inuse;
 
        lck_mtx_assert(&cpu_lock, LCK_MTX_ASSERT_OWNED);
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
 
-       if (size > dtrace_nonroot_maxsize &&
+       if (size > (size_t)dtrace_nonroot_maxsize &&
            !PRIV_POLICY_CHOICE(CRED(), PRIV_ALL, B_FALSE))
                return (EFBIG);
 
-#if defined(__APPLE__)
-       if (size > (sane_size / 8) / (int)NCPU) /* As in kdbg_set_nkdbufs(), roughly. */
-               return (ENOMEM);
-#endif /* __APPLE__ */
-
        cp = cpu_list;
 
        do {
@@ -9994,8 +10625,12 @@ dtrace_buffer_alloc(dtrace_buffer_t *bufs, size_t size, int flags,
 
                ASSERT(buf->dtb_xamot == NULL);
 
+               /* DTrace, please do not eat all the memory. */
+               if (dtrace_buffer_canalloc(size) == B_FALSE)
+                       goto err;
                if ((buf->dtb_tomax = kmem_zalloc(size, KM_NOSLEEP)) == NULL)
                        goto err;
+               dtrace_buffer_memory_inuse += size;
 
                buf->dtb_size = size;
                buf->dtb_flags = flags;
@@ -10005,10 +10640,16 @@ dtrace_buffer_alloc(dtrace_buffer_t *bufs, size_t size, int flags,
                if (flags & DTRACEBUF_NOSWITCH)
                        continue;
 
+               /* DTrace, please do not eat all the memory. */
+               if (dtrace_buffer_canalloc(size) == B_FALSE)
+                       goto err;
                if ((buf->dtb_xamot = kmem_zalloc(size, KM_NOSLEEP)) == NULL)
                        goto err;
+               dtrace_buffer_memory_inuse += size;
        } while ((cp = cp->cpu_next) != cpu_list);
 
+       ASSERT(dtrace_buffer_memory_inuse <= dtrace_buffer_memory_maxsize);
+
        return (0);
 
 err:
@@ -10036,6 +10677,9 @@ err:
                buf->dtb_size = 0;
        } while ((cp = cp->cpu_next) != cpu_list);
 
+       /* Restore the size saved before allocating memory */
+       dtrace_buffer_memory_inuse = size_before_alloc;
+
        return (ENOMEM);
 }
 
@@ -10087,7 +10731,7 @@ dtrace_buffer_reserve(dtrace_buffer_t *buf, size_t needed, size_t align,
                        offs += sizeof (uint32_t);
                }
 
-               if ((soffs = offs + needed) > buf->dtb_size) {
+               if ((uint64_t)(soffs = offs + needed) > buf->dtb_size) {
                        dtrace_buffer_drop(buf);
                        return (-1);
                }
@@ -10158,7 +10802,7 @@ dtrace_buffer_reserve(dtrace_buffer_t *buf, size_t needed, size_t align,
                         * there.  We need to clear the buffer from the current
                         * offset to the end (there may be old gunk there).
                         */
-                       while (offs < buf->dtb_size)
+                       while ((uint64_t)offs < buf->dtb_size)
                                tomax[offs++] = 0;
 
                        /*
@@ -10195,14 +10839,14 @@ dtrace_buffer_reserve(dtrace_buffer_t *buf, size_t needed, size_t align,
                        }
                }
 
-               while (offs + total_off > woffs) {
+               while (offs + total_off > (size_t)woffs) {
                        dtrace_epid_t epid = *(uint32_t *)(tomax + woffs);
                        size_t size;
 
                        if (epid == DTRACE_EPIDNONE) {
                                size = sizeof (uint32_t);
                        } else {
-                               ASSERT(epid <= state->dts_necbs);
+                               ASSERT(epid <= (dtrace_epid_t)state->dts_necbs);
                                ASSERT(state->dts_ecbs[epid - 1] != NULL);
 
                                size = state->dts_ecbs[epid - 1]->dte_size;
@@ -10237,7 +10881,7 @@ dtrace_buffer_reserve(dtrace_buffer_t *buf, size_t needed, size_t align,
                                        buf->dtb_offset = 0;
                                        woffs = total_off;
 
-                                       while (woffs < buf->dtb_size)
+                                       while ((uint64_t)woffs < buf->dtb_size)
                                                tomax[woffs++] = 0;
                                }
 
@@ -10354,9 +10998,15 @@ dtrace_buffer_free(dtrace_buffer_t *bufs)
                if (buf->dtb_xamot != NULL) {
                        ASSERT(!(buf->dtb_flags & DTRACEBUF_NOSWITCH));
                        kmem_free(buf->dtb_xamot, buf->dtb_size);
+
+                       ASSERT(dtrace_buffer_memory_inuse >= buf->dtb_size);
+                       dtrace_buffer_memory_inuse -= buf->dtb_size;
                }
 
                kmem_free(buf->dtb_tomax, buf->dtb_size);
+               ASSERT(dtrace_buffer_memory_inuse >= buf->dtb_size);
+               dtrace_buffer_memory_inuse -= buf->dtb_size;
+
                buf->dtb_size = 0;
                buf->dtb_tomax = NULL;
                buf->dtb_xamot = NULL;
@@ -10390,9 +11040,8 @@ dtrace_enabling_add(dtrace_enabling_t *enab, dtrace_ecbdesc_t *ecb)
        ASSERT(enab->dten_probegen == 0);
        ASSERT(enab->dten_next == NULL && enab->dten_prev == NULL);
 
-#if defined(__APPLE__)
-       if (ecb == NULL) return; /* XXX protection against gcc 4.0 botch on x86 */
-#endif /* __APPLE__ */
+       /* APPLE NOTE: this protects against gcc 4.0 botch on x86 */
+       if (ecb == NULL) return;
 
        if (enab->dten_ndesc < enab->dten_maxdesc) {
                enab->dten_desc[enab->dten_ndesc++] = ecb;
@@ -10498,6 +11147,7 @@ dtrace_enabling_destroy(dtrace_enabling_t *enab)
                ASSERT(enab->dten_vstate->dtvs_state != NULL);
                ASSERT(enab->dten_vstate->dtvs_state->dts_nretained > 0);
                enab->dten_vstate->dtvs_state->dts_nretained--;
+                dtrace_retained_gen++;
        }
 
        if (enab->dten_prev == NULL) {
@@ -10540,6 +11190,7 @@ dtrace_enabling_retain(dtrace_enabling_t *enab)
                return (ENOSPC);
 
        state->dts_nretained++;
+        dtrace_retained_gen++;
 
        if (dtrace_retained == NULL) {
                dtrace_retained = enab;
@@ -10592,16 +11243,17 @@ dtrace_enabling_replicate(dtrace_state_t *state, dtrace_probedesc_t *match,
                        dtrace_ecbdesc_t *ep = enab->dten_desc[i];
                        dtrace_probedesc_t *pd = &ep->dted_probe;
 
-                       if (strcmp(pd->dtpd_provider, match->dtpd_provider))
+                       /* APPLE NOTE: Darwin employs size bounded string operation. */
+                       if (strncmp(pd->dtpd_provider, match->dtpd_provider, DTRACE_PROVNAMELEN))
                                continue;
 
-                       if (strcmp(pd->dtpd_mod, match->dtpd_mod))
+                       if (strncmp(pd->dtpd_mod, match->dtpd_mod, DTRACE_MODNAMELEN))
                                continue;
 
-                       if (strcmp(pd->dtpd_func, match->dtpd_func))
+                       if (strncmp(pd->dtpd_func, match->dtpd_func, DTRACE_FUNCNAMELEN))
                                continue;
 
-                       if (strcmp(pd->dtpd_name, match->dtpd_name))
+                       if (strncmp(pd->dtpd_name, match->dtpd_name, DTRACE_NAMELEN))
                                continue;
 
                        /*
@@ -10654,7 +11306,7 @@ static int
 dtrace_enabling_match(dtrace_enabling_t *enab, int *nmatched)
 {
        int i = 0;
-       int matched = 0;
+       int total_matched = 0, matched = 0;
 
        lck_mtx_assert(&cpu_lock, LCK_MTX_ASSERT_OWNED);
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
@@ -10665,7 +11317,14 @@ dtrace_enabling_match(dtrace_enabling_t *enab, int *nmatched)
                enab->dten_current = ep;
                enab->dten_error = 0;
 
-               matched += dtrace_probe_enable(&ep->dted_probe, enab);
+               /*
+                * If a provider failed to enable a probe then get out and
+                * let the consumer know we failed.
+                */
+               if ((matched = dtrace_probe_enable(&ep->dted_probe, enab)) < 0)
+                       return (EBUSY);
+
+               total_matched += matched;
 
                if (enab->dten_error != 0) {
                        /*
@@ -10693,7 +11352,7 @@ dtrace_enabling_match(dtrace_enabling_t *enab, int *nmatched)
 
        enab->dten_probegen = dtrace_probegen;
        if (nmatched != NULL)
-               *nmatched = matched;
+               *nmatched = total_matched;
 
        return (0);
 }
@@ -10707,43 +11366,26 @@ dtrace_enabling_matchall(void)
        lck_mtx_lock(&dtrace_lock);
 
        /*
-        * Because we can be called after dtrace_detach() has been called, we
-        * cannot assert that there are retained enablings.  We can safely
-        * load from dtrace_retained, however:  the taskq_destroy() at the
-        * end of dtrace_detach() will block pending our completion.
+        * Iterate over all retained enablings to see if any probes match
+        * against them.  We only perform this operation on enablings for which
+        * we have sufficient permissions by virtue of being in the global zone
+        * or in the same zone as the DTrace client.  Because we can be called
+        * after dtrace_detach() has been called, we cannot assert that there
+        * are retained enablings.  We can safely load from dtrace_retained,
+        * however:  the taskq_destroy() at the end of dtrace_detach() will
+        * block pending our completion.
         */
-       for (enab = dtrace_retained; enab != NULL; enab = enab->dten_next)
-               (void) dtrace_enabling_match(enab, NULL);
-
-       lck_mtx_unlock(&dtrace_lock);
-       lck_mtx_unlock(&cpu_lock);
-}
-
-static int
-dtrace_enabling_matchstate(dtrace_state_t *state, int *nmatched)
-{
-       dtrace_enabling_t *enab;
-       int matched, total_matched = 0, err;
-
-       lck_mtx_assert(&cpu_lock, LCK_MTX_ASSERT_OWNED);
-       lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
 
+       /*
+        * Darwin doesn't do zones.
+        * Behave as if always in "global" zone."
+        */
        for (enab = dtrace_retained; enab != NULL; enab = enab->dten_next) {
-               ASSERT(enab->dten_vstate->dtvs_state != NULL);
-
-               if (enab->dten_vstate->dtvs_state != state)
-                       continue;
-
-               if ((err = dtrace_enabling_match(enab, &matched)) != 0)
-                       return (err);
-
-               total_matched += matched;
+               (void) dtrace_enabling_match(enab, NULL);
        }
 
-       if (nmatched != NULL)
-               *nmatched = total_matched;
-
-       return (0);
+       lck_mtx_unlock(&dtrace_lock);
+       lck_mtx_unlock(&cpu_lock);
 }
 
 /*
@@ -10798,6 +11440,7 @@ dtrace_enabling_provide(dtrace_provider_t *prv)
 {
        int i, all = 0;
        dtrace_probedesc_t desc;
+        dtrace_genid_t gen;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
        lck_mtx_assert(&dtrace_provider_lock, LCK_MTX_ASSERT_OWNED);
@@ -10808,15 +11451,25 @@ dtrace_enabling_provide(dtrace_provider_t *prv)
        }
 
        do {
-               dtrace_enabling_t *enab = dtrace_retained;
+               dtrace_enabling_t *enab;
                void *parg = prv->dtpv_arg;
 
-               for (; enab != NULL; enab = enab->dten_next) {
+retry:
+               gen = dtrace_retained_gen;
+               for (enab = dtrace_retained; enab != NULL;
+                   enab = enab->dten_next) {
                        for (i = 0; i < enab->dten_ndesc; i++) {
                                desc = enab->dten_desc[i]->dted_probe;
                                lck_mtx_unlock(&dtrace_lock);
                                prv->dtpv_pops.dtps_provide(parg, &desc);
                                lck_mtx_lock(&dtrace_lock);
+                               /*
+                                * Process the retained enablings again if
+                                * they have changed while we weren't holding
+                                * dtrace_lock.
+                                */
+                               if (gen != dtrace_retained_gen)
+                                       goto retry;
                        }
                }
        } while (all && (prv = prv->dtpv_next) != NULL);
@@ -10833,7 +11486,7 @@ dtrace_enabling_provide(dtrace_provider_t *prv)
 static void
 dtrace_dof_error(dof_hdr_t *dof, const char *str)
 {
-#pragma unused(dof)
+#pragma unused(dof) /* __APPLE__ */
        if (dtrace_err_verbose)
                cmn_err(CE_WARN, "failed to process DOF: %s", str);
 
@@ -10906,11 +11559,7 @@ dtrace_dof_create(dtrace_state_t *state)
 }
 
 static dof_hdr_t *
-#if defined(__APPLE__)
 dtrace_dof_copyin(user_addr_t uarg, int *errp)
-#else
-dtrace_dof_copyin(uintptr_t uarg, int *errp)
-#endif
 {
        dof_hdr_t hdr, *dof;
 
@@ -10919,11 +11568,7 @@ dtrace_dof_copyin(uintptr_t uarg, int *errp)
        /*
         * First, we're going to copyin() the sizeof (dof_hdr_t).
         */
-#if defined(__APPLE__)
        if (copyin(uarg, &hdr, sizeof (hdr)) != 0) {
-#else
-       if (copyin((void *)uarg, &hdr, sizeof (hdr)) != 0) {
-#endif
                dtrace_dof_error(NULL, "failed to copyin DOF header");
                *errp = EFAULT;
                return (NULL);
@@ -10933,7 +11578,7 @@ dtrace_dof_copyin(uintptr_t uarg, int *errp)
         * Now we'll allocate the entire DOF and copy it in -- provided
         * that the length isn't outrageous.
         */
-       if (hdr.dofh_loadsz >= dtrace_dof_maxsize) {
+       if (hdr.dofh_loadsz >= (uint64_t)dtrace_dof_maxsize) {
                dtrace_dof_error(&hdr, "load size exceeds maximum");
                *errp = E2BIG;
                return (NULL);
@@ -10947,21 +11592,16 @@ dtrace_dof_copyin(uintptr_t uarg, int *errp)
 
        dof = dt_kmem_alloc_aligned(hdr.dofh_loadsz, 8, KM_SLEEP);
 
-#if defined(__APPLE__)
-       if (copyin(uarg, dof, hdr.dofh_loadsz) != 0) {
-#else
-       if (copyin((void *)uarg, dof, hdr.dofh_loadsz) != 0) {
-#endif
-               dt_kmem_free_aligned(dof, hdr.dofh_loadsz);
-               *errp = EFAULT;
-               return (NULL);
-       }
+        if (copyin(uarg, dof, hdr.dofh_loadsz) != 0  ||
+         dof->dofh_loadsz != hdr.dofh_loadsz) {
+           dt_kmem_free_aligned(dof, hdr.dofh_loadsz);
+           *errp = EFAULT;
+           return (NULL);
+       }           
 
        return (dof);
 }
 
-#if defined(__APPLE__)
-
 static dof_hdr_t *
 dtrace_dof_copyin_from_proc(proc_t* p, user_addr_t uarg, int *errp)
 {
@@ -10982,7 +11622,7 @@ dtrace_dof_copyin_from_proc(proc_t* p, user_addr_t uarg, int *errp)
         * Now we'll allocate the entire DOF and copy it in -- provided
         * that the length isn't outrageous.
         */
-       if (hdr.dofh_loadsz >= dtrace_dof_maxsize) {
+       if (hdr.dofh_loadsz >= (uint64_t)dtrace_dof_maxsize) {
                dtrace_dof_error(&hdr, "load size exceeds maximum");
                *errp = E2BIG;
                return (NULL);
@@ -11005,8 +11645,6 @@ dtrace_dof_copyin_from_proc(proc_t* p, user_addr_t uarg, int *errp)
        return (dof);
 }
 
-#endif /* __APPLE__ */
-
 static dof_hdr_t *
 dtrace_dof_property(const char *name)
 {
@@ -11021,7 +11659,7 @@ dtrace_dof_property(const char *name)
         * as an integer array, and then squeeze it into a byte array.
         */
        if (ddi_prop_lookup_int_array(DDI_DEV_T_ANY, dtrace_devi, 0,
-           (char *)name, (int **)&buf, &len) != DDI_PROP_SUCCESS)
+           name, (int **)&buf, &len) != DDI_PROP_SUCCESS)
                return (NULL);
 
        for (i = 0; i < len; i++)
@@ -11039,7 +11677,7 @@ dtrace_dof_property(const char *name)
                return (NULL);
        }
 
-       if (loadsz >= dtrace_dof_maxsize) {
+       if (loadsz >= (uint64_t)dtrace_dof_maxsize) {
                ddi_prop_free(buf);
                dtrace_dof_error(NULL, "oversized DOF");
                return (NULL);
@@ -11130,6 +11768,9 @@ dtrace_dof_probedesc(dof_hdr_t *dof, dof_sec_t *sec, dtrace_probedesc_t *desc)
            (char *)(str + probe->dofp_provider),
            MIN(DTRACE_PROVNAMELEN - 1, size - probe->dofp_provider));
 
+       /* APPLE NOTE: Darwin employs size bounded string operation. */
+       desc->dtpd_provider[DTRACE_PROVNAMELEN - 1] = '\0';
+
        if (probe->dofp_mod >= strtab->dofs_size) {
                dtrace_dof_error(dof, "corrupt probe module");
                return (NULL);
@@ -11138,6 +11779,9 @@ dtrace_dof_probedesc(dof_hdr_t *dof, dof_sec_t *sec, dtrace_probedesc_t *desc)
        (void) strncpy(desc->dtpd_mod, (char *)(str + probe->dofp_mod),
            MIN(DTRACE_MODNAMELEN - 1, size - probe->dofp_mod));
 
+       /* APPLE NOTE: Darwin employs size bounded string operation. */
+       desc->dtpd_mod[DTRACE_MODNAMELEN - 1] = '\0';
+
        if (probe->dofp_func >= strtab->dofs_size) {
                dtrace_dof_error(dof, "corrupt probe function");
                return (NULL);
@@ -11146,6 +11790,9 @@ dtrace_dof_probedesc(dof_hdr_t *dof, dof_sec_t *sec, dtrace_probedesc_t *desc)
        (void) strncpy(desc->dtpd_func, (char *)(str + probe->dofp_func),
            MIN(DTRACE_FUNCNAMELEN - 1, size - probe->dofp_func));
 
+       /* APPLE NOTE: Darwin employs size bounded string operation. */ 
+       desc->dtpd_func[DTRACE_FUNCNAMELEN - 1] = '\0';
+
        if (probe->dofp_name >= strtab->dofs_size) {
                dtrace_dof_error(dof, "corrupt probe name");
                return (NULL);
@@ -11154,6 +11801,9 @@ dtrace_dof_probedesc(dof_hdr_t *dof, dof_sec_t *sec, dtrace_probedesc_t *desc)
        (void) strncpy(desc->dtpd_name, (char *)(str + probe->dofp_name),
            MIN(DTRACE_NAMELEN - 1, size - probe->dofp_name));
 
+       /* APPLE NOTE: Darwin employs size bounded string operation. */ 
+       desc->dtpd_name[DTRACE_NAMELEN - 1] = '\0';
+
        return (desc);
 }
 
@@ -11166,7 +11816,9 @@ dtrace_dof_difo(dof_hdr_t *dof, dof_sec_t *sec, dtrace_vstate_t *vstate,
        dof_difohdr_t *dofd;
        uintptr_t daddr = (uintptr_t)dof;
        size_t max_size = dtrace_difo_maxsize;
-       int i, l, n;
+       uint_t i;
+       int l, n;
+               
 
        static const struct {
                int section;
@@ -11192,11 +11844,7 @@ dtrace_dof_difo(dof_hdr_t *dof, dof_sec_t *sec, dtrace_vstate_t *vstate,
                offsetof(dtrace_difo_t, dtdo_varlen), sizeof (dtrace_difv_t),
                sizeof (uint_t), "multiple variable tables" },
 
-#if !defined(__APPLE__)
-               { DOF_SECT_NONE, 0, 0, 0, NULL }
-#else
                { DOF_SECT_NONE, 0, 0, 0, 0, NULL }
-#endif /* __APPLE__ */
        };
 
        if (sec->dofs_type != DOF_SECT_DIFOHDR) {
@@ -11238,7 +11886,8 @@ dtrace_dof_difo(dof_hdr_t *dof, dof_sec_t *sec, dtrace_vstate_t *vstate,
                ttl += subsec->dofs_size;
 
                for (i = 0; difo[i].section != DOF_SECT_NONE; i++) {
-                       if (subsec->dofs_type != difo[i].section)
+
+                       if (subsec->dofs_type != (uint32_t)difo[i].section)
                                continue;
 
                        if (!(subsec->dofs_flags & DOF_SECF_LOAD)) {
@@ -11246,7 +11895,7 @@ dtrace_dof_difo(dof_hdr_t *dof, dof_sec_t *sec, dtrace_vstate_t *vstate,
                                goto err;
                        }
 
-                       if (subsec->dofs_align != difo[i].align) {
+                       if (subsec->dofs_align != (uint32_t)difo[i].align) {
                                dtrace_dof_error(dof, "bad alignment");
                                goto err;
                        }
@@ -11259,7 +11908,7 @@ dtrace_dof_difo(dof_hdr_t *dof, dof_sec_t *sec, dtrace_vstate_t *vstate,
                                goto err;
                        }
 
-                       if (difo[i].entsize != subsec->dofs_entsize) {
+                       if ((uint32_t)difo[i].entsize != subsec->dofs_entsize) {
                                dtrace_dof_error(dof, "entry size mismatch");
                                goto err;
                        }
@@ -11291,7 +11940,7 @@ dtrace_dof_difo(dof_hdr_t *dof, dof_sec_t *sec, dtrace_vstate_t *vstate,
                        goto err;
                }
        }
-
+       
        if (dp->dtdo_buf == NULL) {
                /*
                 * We can't have a DIF object without DIF text.
@@ -11538,76 +12187,10 @@ err:
        return (NULL);
 }
 
-#if !defined(__APPLE__) /* APPLE dyld has already done this for us */
 /*
- * Apply the relocations from the specified 'sec' (a DOF_SECT_URELHDR) to the
- * specified DOF.  At present, this amounts to simply adding 'ubase' to the
- * site of any user SETX relocations to account for load object base address.
- * In the future, if we need other relocations, this function can be extended.
+ * APPLE NOTE: dyld handles dof relocation.
+ * Darwin does not need dtrace_dof_relocate()
  */
-static int
-dtrace_dof_relocate(dof_hdr_t *dof, dof_sec_t *sec, uint64_t ubase)
-{
-       uintptr_t daddr = (uintptr_t)dof;
-       dof_relohdr_t *dofr =
-           (dof_relohdr_t *)(uintptr_t)(daddr + sec->dofs_offset);
-       dof_sec_t *ss, *rs, *ts;
-       dof_relodesc_t *r;
-       uint_t i, n;
-
-       if (sec->dofs_size < sizeof (dof_relohdr_t) ||
-           sec->dofs_align != sizeof (dof_secidx_t)) {
-               dtrace_dof_error(dof, "invalid relocation header");
-               return (-1);
-       }
-
-       ss = dtrace_dof_sect(dof, DOF_SECT_STRTAB, dofr->dofr_strtab);
-       rs = dtrace_dof_sect(dof, DOF_SECT_RELTAB, dofr->dofr_relsec);
-       ts = dtrace_dof_sect(dof, DOF_SECT_NONE, dofr->dofr_tgtsec);
-
-       if (ss == NULL || rs == NULL || ts == NULL)
-               return (-1); /* dtrace_dof_error() has been called already */
-
-       if (rs->dofs_entsize < sizeof (dof_relodesc_t) ||
-           rs->dofs_align != sizeof (uint64_t)) {
-               dtrace_dof_error(dof, "invalid relocation section");
-               return (-1);
-       }
-
-       r = (dof_relodesc_t *)(uintptr_t)(daddr + rs->dofs_offset);
-       n = rs->dofs_size / rs->dofs_entsize;
-
-       for (i = 0; i < n; i++) {
-               uintptr_t taddr = daddr + ts->dofs_offset + r->dofr_offset;
-
-               switch (r->dofr_type) {
-               case DOF_RELO_NONE:
-                       break;
-               case DOF_RELO_SETX:
-                       if (r->dofr_offset >= ts->dofs_size || r->dofr_offset +
-                           sizeof (uint64_t) > ts->dofs_size) {
-                               dtrace_dof_error(dof, "bad relocation offset");
-                               return (-1);
-                       }
-
-                       if (!IS_P2ALIGNED(taddr, sizeof (uint64_t))) {
-                               dtrace_dof_error(dof, "misaligned setx relo");
-                               return (-1);
-                       }
-
-                       *(uint64_t *)taddr += ubase;
-                       break;
-               default:
-                       dtrace_dof_error(dof, "invalid relocation type");
-                       return (-1);
-               }
-
-               r = (dof_relodesc_t *)((uintptr_t)r + rs->dofs_entsize);
-       }
-
-       return (0);
-}
-#endif /* __APPLE__ */
 
 /*
  * The dof_hdr_t passed to dtrace_dof_slurp() should be a partially validated
@@ -11619,6 +12202,7 @@ static int
 dtrace_dof_slurp(dof_hdr_t *dof, dtrace_vstate_t *vstate, cred_t *cr,
     dtrace_enabling_t **enabp, uint64_t ubase, int noprobes)
 {
+#pragma unused(ubase) /* __APPLE__ */
        uint64_t len = dof->dofh_loadsz, seclen;
        uintptr_t daddr = (uintptr_t)dof;
        dtrace_ecbdesc_t *ep;
@@ -11650,21 +12234,13 @@ dtrace_dof_slurp(dof_hdr_t *dof, dtrace_vstate_t *vstate, cred_t *cr,
                return (-1);
        }
 
-#if !defined(__APPLE__)
-       if (dof->dofh_ident[DOF_ID_VERSION] != DOF_VERSION_1 &&
-           dof->dofh_ident[DOF_ID_VERSION] != DOF_VERSION_2) {
-               dtrace_dof_error(dof, "DOF version mismatch");
-               return (-1);
-       }
-#else
        /*
-        * We only support DOF_VERSION_3 for now.
+        * APPLE NOTE: Darwin only supports DOF_VERSION_3 for now.
         */
        if (dof->dofh_ident[DOF_ID_VERSION] != DOF_VERSION_3) {
                dtrace_dof_error(dof, "DOF version mismatch");
                return (-1);
        }
-#endif
 
        if (dof->dofh_ident[DOF_ID_DIFVERS] != DIF_VERSION_2) {
                dtrace_dof_error(dof, "DOF uses unsupported instruction set");
@@ -11768,32 +12344,10 @@ dtrace_dof_slurp(dof_hdr_t *dof, dtrace_vstate_t *vstate, cred_t *cr,
                }
        }
 
-#if !defined(__APPLE__)
-       /*
-        * APPLE NOTE: We have no relocation to perform. All dof values are
-        * relative offsets.
-        */
-
        /*
-        * Take a second pass through the sections and locate and perform any
-        * relocations that are present.  We do this after the first pass to
-        * be sure that all sections have had their headers validated.
+        * APPLE NOTE: We have no further relocation to perform.
+        * All dof values are relative offsets.
         */
-       for (i = 0; i < dof->dofh_secnum; i++) {
-               dof_sec_t *sec = (dof_sec_t *)(daddr +
-                   (uintptr_t)dof->dofh_secoff + i * dof->dofh_secsize);
-
-               if (!(sec->dofs_flags & DOF_SECF_LOAD))
-                       continue; /* skip sections that are not loadable */
-
-               switch (sec->dofs_type) {
-               case DOF_SECT_URELHDR:
-                       if (dtrace_dof_relocate(dof, sec, ubase) != 0)
-                               return (-1);
-                       break;
-               }
-       }
-#endif /* __APPLE__ */
 
        if ((enab = *enabp) == NULL)
                enab = *enabp = dtrace_enabling_create(vstate);
@@ -11805,22 +12359,18 @@ dtrace_dof_slurp(dof_hdr_t *dof, dtrace_vstate_t *vstate, cred_t *cr,
                if (sec->dofs_type != DOF_SECT_ECBDESC)
                        continue;
 
-#if !defined(__APPLE__)
-               if ((ep = dtrace_dof_ecbdesc(dof, sec, vstate, cr)) == NULL) {
-                       dtrace_enabling_destroy(enab);
-                       *enabp = NULL;
-                       return (-1);
-               }
-#else
-               /* XXX Defend against gcc 4.0 botch on x86 (not all paths out of inlined dtrace_dof_ecbdesc
-                  are checked for the NULL return value.) */
+               /*
+                * APPLE NOTE: Defend against gcc 4.0 botch on x86.
+                * not all paths out of inlined dtrace_dof_ecbdesc
+                * are checked for the NULL return value.
+                * Check for NULL explicitly here.
+               */
                ep = dtrace_dof_ecbdesc(dof, sec, vstate, cr);
                if (ep == NULL) {
                        dtrace_enabling_destroy(enab);
                        *enabp = NULL;
                        return (-1);
                }
-#endif /* __APPLE__ */
                
                dtrace_enabling_add(enab, ep);
        }
@@ -11835,7 +12385,8 @@ dtrace_dof_slurp(dof_hdr_t *dof, dtrace_vstate_t *vstate, cred_t *cr,
 static int
 dtrace_dof_options(dof_hdr_t *dof, dtrace_state_t *state)
 {
-       int i, rval;
+       uint_t i;
+       int rval;
        uint32_t entsize;
        size_t offs;
        dof_optdesc_t *desc;
@@ -11872,7 +12423,7 @@ dtrace_dof_options(dof_hdr_t *dof, dtrace_state_t *state)
                                return (EINVAL);
                        }
 
-                       if (desc->dofo_value == DTRACEOPT_UNSET) {
+                       if (desc->dofo_value == (uint64_t)DTRACEOPT_UNSET) {
                                dtrace_dof_error(dof, "unset option");
                                return (EINVAL);
                        }
@@ -11891,17 +12442,14 @@ dtrace_dof_options(dof_hdr_t *dof, dtrace_state_t *state)
 /*
  * DTrace Consumer State Functions
  */
-#if defined(__APPLE__)
-static 
-#endif /* __APPLE__ */
-int
+static int
 dtrace_dstate_init(dtrace_dstate_t *dstate, size_t size)
 {
        size_t hashsize, maxper, min_size, chunksize = dstate->dtds_chunksize;
        void *base;
        uintptr_t limit;
        dtrace_dynvar_t *dvar, *next, *start;
-       int i;
+       size_t i;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
        ASSERT(dstate->dtds_base == NULL && dstate->dtds_percpu == NULL);
@@ -11954,7 +12502,7 @@ dtrace_dstate_init(dtrace_dstate_t *dstate, size_t size)
        maxper = (limit - (uintptr_t)start) / (int)NCPU;
        maxper = (maxper / dstate->dtds_chunksize) * dstate->dtds_chunksize;
 
-       for (i = 0; i < (int)NCPU; i++) {
+       for (i = 0; i < NCPU; i++) {
                dstate->dtds_percpu[i].dtdsc_free = dvar = start;
 
                /*
@@ -11964,7 +12512,7 @@ dtrace_dstate_init(dtrace_dstate_t *dstate, size_t size)
                 * whatever is left over.  In either case, we set the limit to
                 * be the limit of the dynamic variable space.
                 */
-               if (maxper == 0 || i == (int)NCPU - 1) {
+               if (maxper == 0 || i == NCPU - 1) {
                        limit = (uintptr_t)base + size;
                        start = NULL;
                } else {
@@ -11992,10 +12540,7 @@ dtrace_dstate_init(dtrace_dstate_t *dstate, size_t size)
        return (0);
 }
 
-#if defined(__APPLE__)
-static 
-#endif /* __APPLE__ */
-void
+static void
 dtrace_dstate_fini(dtrace_dstate_t *dstate)
 {
        lck_mtx_assert(&cpu_lock, LCK_MTX_ASSERT_OWNED);
@@ -12070,11 +12615,8 @@ dtrace_state_deadman(dtrace_state_t *state)
        state->dts_alive = now;
 }
 
-#if defined(__APPLE__)
-static 
-#endif /* __APPLE__ */
-dtrace_state_t *
-dtrace_state_create(dev_t *devp, cred_t *cr)
+static int
+dtrace_state_create(dev_t *devp, cred_t *cr, dtrace_state_t **new_state)
 {
        minor_t minor;
        major_t major;
@@ -12086,16 +12628,15 @@ dtrace_state_create(dev_t *devp, cred_t *cr)
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
        lck_mtx_assert(&cpu_lock, LCK_MTX_ASSERT_OWNED);
 
-#if !defined(__APPLE__)
-       minor = (minor_t)(uintptr_t)vmem_alloc(dtrace_minor, 1,
-           VM_BESTFIT | VM_SLEEP);
-#else
+       /* Cause restart */
+       *new_state = NULL;
+       
        /*
         * Darwin's DEVFS layer acquired the minor number for this "device" when it called
         * dtrace_devfs_clone_func(). At that time, dtrace_devfs_clone_func() proposed a minor number
         * (next unused according to vmem_alloc()) and then immediately put the number back in play
         * (by calling vmem_free()). Now that minor number is being used for an open, so committing it
-        * to use. The following vmem_alloc() must deliver that same minor number.
+        * to use. The following vmem_alloc() must deliver that same minor number. FIXME.
         */
 
        minor = (minor_t)(uintptr_t)vmem_alloc(dtrace_minor, 1,
@@ -12107,18 +12648,16 @@ dtrace_state_create(dev_t *devp, cred_t *cr)
                        printf("dtrace_open: couldn't re-acquire vended minor number %d. Instead got %d\n", 
                                        getminor(*devp), minor);
                        vmem_free(dtrace_minor, (void *)(uintptr_t)minor, 1);
-                       return NULL;
+                       return (ERESTART);      /* can't reacquire */
                }
        } else {
         /* NULL==devp iff "Anonymous state" (see dtrace_anon_property),
                 * so just vend the minor device number here de novo since no "open" has occurred. */
        }
 
-#endif /* __APPLE__ */
-
        if (ddi_soft_state_zalloc(dtrace_softstate, minor) != DDI_SUCCESS) {
                vmem_free(dtrace_minor, (void *)(uintptr_t)minor, 1);
-               return (NULL);
+               return (EAGAIN);        /* temporary resource shortage */
        }
 
        state = ddi_get_soft_state(dtrace_softstate, minor);
@@ -12231,18 +12770,13 @@ dtrace_state_create(dev_t *devp, cred_t *cr)
                         * If we have all privs in whatever zone this is,
                         * we can do destructive things to processes which
                         * have altered credentials.
+                        *
+                        * APPLE NOTE: Darwin doesn't do zones.
+                        * Behave as if zone always has destructive privs.
                         */
-#if !defined(__APPLE__)
-                       if (priv_isequalset(priv_getset(cr, PRIV_EFFECTIVE),
-                           cr->cr_zone->zone_privset)) {
-                               state->dts_cred.dcr_action |=
-                                       DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG;
-                       }
-#else
-                       /* Darwin doesn't do zones. */
+
                        state->dts_cred.dcr_action |=
                                DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG;
-#endif /* __APPLE__ */
                }
 
                /*
@@ -12282,18 +12816,12 @@ dtrace_state_create(dev_t *devp, cred_t *cr)
                         * If we have all privs in whatever zone this is,
                         * we can do destructive things to processes which
                         * have altered credentials.
-                        */
-#if !defined(__APPLE__)
-                       if (priv_isequalset(priv_getset(cr, PRIV_EFFECTIVE),
-                           cr->cr_zone->zone_privset)) {
-                               state->dts_cred.dcr_action |=
-                                   DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG;
-                       }
-#else
-                       /* Darwin doesn't do zones. */
+                        *
+                        * APPLE NOTE: Darwin doesn't do zones.                  
+                        * Behave as if zone always has destructive privs.
+                        */                     
                        state->dts_cred.dcr_action |=
                                DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG;
-#endif /* __APPLE__ */
                }
 
                /*
@@ -12313,7 +12841,8 @@ dtrace_state_create(dev_t *devp, cred_t *cr)
                }
        }
 
-       return (state);
+       *new_state = state;
+       return(0);  /* Success */
 }
 
 static int
@@ -12351,7 +12880,7 @@ dtrace_state_buffer(dtrace_state_t *state, dtrace_buffer_t *buf, int which)
                        flags |= DTRACEBUF_INACTIVE;
        }
 
-       for (size = opt[which]; size >= sizeof (uint64_t); size >>= 1) {
+       for (size = opt[which]; (size_t)size >= sizeof (uint64_t); size >>= 1) {
                /*
                 * The size must be 8-byte aligned.  If the size is not 8-byte
                 * aligned, drop it down by the difference.
@@ -12546,7 +13075,7 @@ dtrace_state_go(dtrace_state_t *state, processorid_t *cpu)
                         * a buffer to use as scratch.
                         */
                        if (opt[DTRACEOPT_BUFSIZE] == DTRACEOPT_UNSET ||
-                           opt[DTRACEOPT_BUFSIZE] < state->dts_needed) {
+                         (size_t)opt[DTRACEOPT_BUFSIZE] < state->dts_needed) {
                                opt[DTRACEOPT_BUFSIZE] = state->dts_needed;
                        }
                }
@@ -12774,7 +13303,12 @@ dtrace_state_option(dtrace_state_t *state, dtrace_optid_t option,
 
        switch (option) {
        case DTRACEOPT_DESTRUCTIVE:
-               if (dtrace_destructive_disallow)
+               /*
+                * Prevent consumers from enabling destructive actions if DTrace
+                * is running in a restricted environment, or if actions are
+                * disallowed.
+                */
+               if (dtrace_is_restricted() || dtrace_destructive_disallow)
                        return (EACCES);
 
                state->dts_cred.dcr_destructive = 1;
@@ -12904,7 +13438,7 @@ dtrace_state_destroy(dtrace_state_t *state)
        kmem_free(state->dts_ecbs, state->dts_necbs * sizeof (dtrace_ecb_t *));
 
        if (state->dts_aggregations != NULL) {
-#ifdef DEBUG
+#if DEBUG
                for (i = 0; i < state->dts_naggregations; i++)
                        ASSERT(state->dts_aggregations[i] == NULL);
 #endif
@@ -12991,10 +13525,9 @@ dtrace_anon_property(void)
                 * If we haven't allocated an anonymous state, we'll do so now.
                 */
                if ((state = dtrace_anon.dta_state) == NULL) {
-                       state = dtrace_state_create(NULL, NULL);
+                       rv = dtrace_state_create(NULL, NULL, &state);
                        dtrace_anon.dta_state = state;
-
-                       if (state == NULL) {
+                       if (rv != 0 || state == NULL) {
                                /*
                                 * This basically shouldn't happen:  the only
                                 * failure mode from dtrace_state_create() is a
@@ -13059,14 +13592,15 @@ static void
 dtrace_helper_trace(dtrace_helper_action_t *helper,
     dtrace_mstate_t *mstate, dtrace_vstate_t *vstate, int where)
 {
-       uint32_t size, next, nnext, i;
+       uint32_t size, next, nnext;
+       int i;
        dtrace_helptrace_t *ent;
        uint16_t flags = cpu_core[CPU->cpu_id].cpuc_dtrace_flags;
 
        if (!dtrace_helptrace_enabled)
                return;
 
-       ASSERT(vstate->dtvs_nlocals <= dtrace_helptrace_nlocals);
+       ASSERT((uint32_t)vstate->dtvs_nlocals <= dtrace_helptrace_nlocals);
 
        /*
         * What would a tracing framework be without its own tracing
@@ -13204,7 +13738,7 @@ err:
        mstate->dtms_arg[0] = sarg0;
        mstate->dtms_arg[1] = sarg1;
 
-       return (NULL);
+       return (0);
 }
 
 static void
@@ -13226,19 +13760,12 @@ dtrace_helper_action_destroy(dtrace_helper_action_t *helper,
        kmem_free(helper, sizeof (dtrace_helper_action_t));
 }
 
-#if !defined(__APPLE__)
-static int
-dtrace_helper_destroygen(int gen)
-{
-       proc_t *p = curproc;
-#else
 static int
 dtrace_helper_destroygen(proc_t* p, int gen)
 {
-#endif
        dtrace_helpers_t *help = p->p_dtrace_helpers;
        dtrace_vstate_t *vstate;
-       int i;
+       uint_t i;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
 
@@ -13336,13 +13863,8 @@ dtrace_helper_validate(dtrace_helper_action_t *helper)
        return (err == 0);
 }
 
-#if !defined(__APPLE__)
-static int
-dtrace_helper_action_add(int which, dtrace_ecbdesc_t *ep)
-#else
 static int
 dtrace_helper_action_add(proc_t* p, int which, dtrace_ecbdesc_t *ep)
-#endif
 {
        dtrace_helpers_t *help;
        dtrace_helper_action_t *helper, *last;
@@ -13354,11 +13876,7 @@ dtrace_helper_action_add(proc_t* p, int which, dtrace_ecbdesc_t *ep)
        if (which < 0 || which >= DTRACE_NHELPER_ACTIONS)
                return (EINVAL);
 
-#if !defined(__APPLE__)
-       help = curproc->p_dtrace_helpers;
-#else
        help = p->p_dtrace_helpers;
-#endif
        last = help->dthps_actions[which];
        vstate = &help->dthps_vstate;
 
@@ -13411,7 +13929,7 @@ dtrace_helper_action_add(proc_t* p, int which, dtrace_ecbdesc_t *ep)
                last->dtha_next = helper;
        }
 
-       if (vstate->dtvs_nlocals > dtrace_helptrace_nlocals) {
+       if ((uint32_t)vstate->dtvs_nlocals > dtrace_helptrace_nlocals) {
                dtrace_helptrace_nlocals = vstate->dtvs_nlocals;
                dtrace_helptrace_next = 0;
        }
@@ -13469,7 +13987,7 @@ dtrace_helper_provider_register(proc_t *p, dtrace_helpers_t *help,
                 * off to the meta provider.
                 */
 
-               int i;
+               uint_t i;
                lck_mtx_unlock(&dtrace_lock);
 
                for (i = 0; i < help->dthps_nprovs; i++) {
@@ -13481,25 +13999,15 @@ dtrace_helper_provider_register(proc_t *p, dtrace_helpers_t *help,
        lck_mtx_unlock(&dtrace_meta_lock);
 }
 
-#if !defined(__APPLE__)
-static int
-dtrace_helper_provider_add(dof_helper_t *dofhp, int gen)
-#else
 static int
 dtrace_helper_provider_add(proc_t* p, dof_helper_t *dofhp, int gen)
-#endif
 {
        dtrace_helpers_t *help;
        dtrace_helper_provider_t *hprov, **tmp_provs;
        uint_t tmp_maxprovs, i;
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
-
-#if !defined(__APPLE__)
-       help = curproc->p_dtrace_helpers;
-#else
        help = p->p_dtrace_helpers;
-#endif
        ASSERT(help != NULL);
 
        /*
@@ -13785,13 +14293,8 @@ dtrace_helper_provider_validate(dof_hdr_t *dof, dof_sec_t *sec)
        return (0);
 }
 
-#if !defined(__APPLE__)
-static int
-dtrace_helper_slurp(dof_hdr_t *dof, dof_helper_t *dhp)
-#else
 static int
 dtrace_helper_slurp(proc_t* p, dof_hdr_t *dof, dof_helper_t *dhp)
-#endif
 {
        dtrace_helpers_t *help;
        dtrace_vstate_t *vstate;
@@ -13801,13 +14304,8 @@ dtrace_helper_slurp(proc_t* p, dof_hdr_t *dof, dof_helper_t *dhp)
 
        lck_mtx_assert(&dtrace_lock, LCK_MTX_ASSERT_OWNED);
 
-#if !defined(__APPLE__)
-       if ((help = curproc->p_dtrace_helpers) == NULL)
-               help = dtrace_helpers_create(curproc);
-#else
        if ((help = p->p_dtrace_helpers) == NULL)
                help = dtrace_helpers_create(p);
-#endif
 
        vstate = &help->dthps_vstate;
 
@@ -13821,7 +14319,7 @@ dtrace_helper_slurp(proc_t* p, dof_hdr_t *dof, dof_helper_t *dhp)
         * Look for helper providers and validate their descriptions.
         */
        if (dhp != NULL) {
-               for (i = 0; i < dof->dofh_secnum; i++) {
+               for (i = 0; (uint32_t)i < dof->dofh_secnum; i++) {
                        dof_sec_t *sec = (dof_sec_t *)(uintptr_t)(daddr +
                            dof->dofh_secoff + i * dof->dofh_secsize);
 
@@ -13845,30 +14343,23 @@ dtrace_helper_slurp(proc_t* p, dof_hdr_t *dof, dof_helper_t *dhp)
                dtrace_ecbdesc_t *ep = enab->dten_desc[i];
                dtrace_probedesc_t *desc = &ep->dted_probe;
 
-               if (strcmp(desc->dtpd_provider, "dtrace") != 0)
+               /* APPLE NOTE: Darwin employs size bounded string operation. */
+               if (!LIT_STRNEQL(desc->dtpd_provider, "dtrace"))
                        continue;
 
-               if (strcmp(desc->dtpd_mod, "helper") != 0)
+               if (!LIT_STRNEQL(desc->dtpd_mod, "helper"))
                        continue;
 
-               if (strcmp(desc->dtpd_func, "ustack") != 0)
+               if (!LIT_STRNEQL(desc->dtpd_func, "ustack"))
                        continue;
 
-#if !defined(__APPLE__)
-               if ((rv = dtrace_helper_action_add(DTRACE_HELPER_ACTION_USTACK, ep)) != 0)
-#else
-               if ((rv = dtrace_helper_action_add(p, DTRACE_HELPER_ACTION_USTACK, ep)) != 0)
-#endif
-               {
+               if ((rv = dtrace_helper_action_add(p, DTRACE_HELPER_ACTION_USTACK,
+                   ep)) != 0) {
                        /*
                         * Adding this helper action failed -- we are now going
                         * to rip out the entire generation and return failure.
                         */
-#if !defined(__APPLE__)
-                       (void) dtrace_helper_destroygen(help->dthps_generation);
-#else
                        (void) dtrace_helper_destroygen(p, help->dthps_generation);
-#endif
                        dtrace_enabling_destroy(enab);
                        dtrace_dof_destroy(dof);
                        return (-1);
@@ -13885,17 +14376,9 @@ dtrace_helper_slurp(proc_t* p, dof_hdr_t *dof, dof_helper_t *dhp)
 
        if (dhp != NULL && nprovs > 0) {
                dhp->dofhp_dof = (uint64_t)(uintptr_t)dof;
-#if !defined(__APPLE__)
-               if (dtrace_helper_provider_add(dhp, gen) == 0) {
-#else
                if (dtrace_helper_provider_add(p, dhp, gen) == 0) {
-#endif
                        lck_mtx_unlock(&dtrace_lock);
-#if !defined(__APPLE__)
-                       dtrace_helper_provider_register(curproc, help, dhp);
-#else
                        dtrace_helper_provider_register(p, help, dhp);
-#endif
                        lck_mtx_lock(&dtrace_lock);
 
                        destroy = 0;
@@ -13908,10 +14391,8 @@ dtrace_helper_slurp(proc_t* p, dof_hdr_t *dof, dof_helper_t *dhp)
        return (gen);
 }
 
-#if defined(__APPLE__)
-
 /*
- * DTrace lazy dof
+ * APPLE NOTE:  DTrace lazy dof implementation
  *
  * DTrace user static probes (USDT probes) and helper actions are loaded
  * in a process by proccessing dof sections. The dof sections are passed
@@ -13968,7 +14449,7 @@ dtrace_helper_slurp(proc_t* p, dof_hdr_t *dof, dof_helper_t *dhp)
  * If the dofs data is claimed by this method, dofs_claimed will be set.
  * Callers should not free claimed dofs.
  */
-int
+static int
 dtrace_lazy_dofs_add(proc_t *p, dof_ioctl_data_t* incoming_dofs, int *dofs_claimed)
 {
        ASSERT(p);
@@ -14050,7 +14531,7 @@ dtrace_lazy_dofs_add(proc_t *p, dof_ioctl_data_t* incoming_dofs, int *dofs_claim
                for (i=0; i<all_dofs->dofiod_count-1; i++) {
                        ASSERT(all_dofs->dofiod_helpers[i].dofhp_dof < all_dofs->dofiod_helpers[i+1].dofhp_dof);
                }
-#endif DEBUG
+#endif /* DEBUG */
 
 unlock:
                lck_mtx_unlock(&p->p_dtrace_sprlock);
@@ -14069,7 +14550,7 @@ unlock:
  * EINVAL: lazy dof is enabled, but the requested generation was not found.
  * EACCES: This removal needs to be handled non-lazily. 
  */
-int
+static int
 dtrace_lazy_dofs_remove(proc_t *p, int generation)
 {
        int rval = EINVAL;
@@ -14315,8 +14796,6 @@ dtrace_lazy_dofs_proc_iterate_doit(proc_t *p, void* ignored)
        return PROC_RETURNED;
 }
 
-#endif /* __APPLE__ */
-
 static dtrace_helpers_t *
 dtrace_helpers_create(proc_t *p)
 {
@@ -14335,19 +14814,12 @@ dtrace_helpers_create(proc_t *p)
        return (help);
 }
 
-#if !defined(__APPLE__)
-static void
-dtrace_helpers_destroy(void)
-{
-       proc_t *p = curproc;
-#else
 static void
 dtrace_helpers_destroy(proc_t* p)
 {
-#endif
        dtrace_helpers_t *help;
        dtrace_vstate_t *vstate;
-       int i;
+       uint_t i;
 
        lck_mtx_lock(&dtrace_lock);
 
@@ -14440,7 +14912,8 @@ dtrace_helpers_duplicate(proc_t *from, proc_t *to)
        dtrace_helper_action_t *helper, *new, *last;
        dtrace_difo_t *dp;
        dtrace_vstate_t *vstate;
-       int i, j, sz, hasprovs = 0;
+       uint_t i;
+       int j, sz, hasprovs = 0;
 
        lck_mtx_lock(&dtrace_lock);
        ASSERT(from->p_dtrace_helpers != NULL);
@@ -14475,11 +14948,11 @@ dtrace_helpers_duplicate(proc_t *from, proc_t *to)
                        new->dtha_actions = kmem_alloc(sz, KM_SLEEP);
 
                        for (j = 0; j < new->dtha_nactions; j++) {
-                               dtrace_difo_t *dp = helper->dtha_actions[j];
+                               dtrace_difo_t *dpj = helper->dtha_actions[j];
 
-                               ASSERT(dp != NULL);
-                               dp = dtrace_difo_duplicate(dp, vstate);
-                               new->dtha_actions[j] = dp;
+                               ASSERT(dpj != NULL);
+                               dpj = dtrace_difo_duplicate(dpj, vstate);
+                               new->dtha_actions[j] = dpj;
                        }
 
                        if (last != NULL) {
@@ -14518,26 +14991,260 @@ dtrace_helpers_duplicate(proc_t *from, proc_t *to)
 /*
  * DTrace Hook Functions
  */
+
+/*
+ * APPLE NOTE:  dtrace_modctl_* routines for kext support.
+ * Used to manipulate the modctl list within dtrace xnu.
+ */
+
+modctl_t *dtrace_modctl_list;
+
+static void
+dtrace_modctl_add(struct modctl * newctl)
+{
+       struct modctl *nextp, *prevp;
+
+       ASSERT(newctl != NULL);
+       lck_mtx_assert(&mod_lock, LCK_MTX_ASSERT_OWNED);
+
+       // Insert new module at the front of the list,
+       
+       newctl->mod_next = dtrace_modctl_list;
+       dtrace_modctl_list = newctl;
+
+       /*
+        * If a module exists with the same name, then that module
+        * must have been unloaded with enabled probes. We will move
+        * the unloaded module to the new module's stale chain and
+        * then stop traversing the list.
+        */
+
+       prevp = newctl;
+       nextp = newctl->mod_next;
+    
+       while (nextp != NULL) {
+               if (nextp->mod_loaded) {
+                       /* This is a loaded module. Keep traversing. */
+                       prevp = nextp;
+                       nextp = nextp->mod_next;
+                       continue;
+               }
+               else {
+                       /* Found an unloaded module */
+                       if (strncmp (newctl->mod_modname, nextp->mod_modname, KMOD_MAX_NAME)) {
+                               /* Names don't match. Keep traversing. */
+                               prevp = nextp;
+                               nextp = nextp->mod_next;
+                               continue;
+                       }
+                       else {
+                               /* We found a stale entry, move it. We're done. */
+                               prevp->mod_next = nextp->mod_next;
+                               newctl->mod_stale = nextp;
+                               nextp->mod_next = NULL;
+                               break;
+                       }
+               }
+       }
+}
+
+static modctl_t *
+dtrace_modctl_lookup(struct kmod_info * kmod)
+{
+    lck_mtx_assert(&mod_lock, LCK_MTX_ASSERT_OWNED);
+
+    struct modctl * ctl;
+
+    for (ctl = dtrace_modctl_list; ctl; ctl=ctl->mod_next) {
+       if (ctl->mod_id == kmod->id)
+           return(ctl);
+    }
+    return (NULL);
+}
+
+/*
+ * This routine is called from dtrace_module_unloaded().
+ * It removes a modctl structure and its stale chain
+ * from the kext shadow list.
+ */
 static void
-dtrace_module_loaded(struct modctl *ctl)
+dtrace_modctl_remove(struct modctl * ctl)
+{
+       ASSERT(ctl != NULL);
+       lck_mtx_assert(&mod_lock, LCK_MTX_ASSERT_OWNED);
+       modctl_t *prevp, *nextp, *curp;
+
+       // Remove stale chain first
+       for (curp=ctl->mod_stale; curp != NULL; curp=nextp) {
+               nextp = curp->mod_stale;
+               /* There should NEVER be user symbols allocated at this point */
+               ASSERT(curp->mod_user_symbols == NULL); 
+               kmem_free(curp, sizeof(modctl_t));
+       }
+
+       prevp = NULL;
+       curp = dtrace_modctl_list;
+       
+       while (curp != ctl) {
+               prevp = curp;
+               curp = curp->mod_next;
+       }
+
+       if (prevp != NULL) {
+               prevp->mod_next = ctl->mod_next;
+       }
+       else {
+               dtrace_modctl_list = ctl->mod_next;
+       }
+
+       /* There should NEVER be user symbols allocated at this point */
+       ASSERT(ctl->mod_user_symbols == NULL);
+
+       kmem_free (ctl, sizeof(modctl_t));
+}
+       
+/*
+ * APPLE NOTE: The kext loader will call dtrace_module_loaded
+ * when the kext is loaded in memory, but before calling the
+ * kext's start routine.
+ *
+ * Return 0 on success
+ * Return -1 on failure
+ */
+       
+static int
+dtrace_module_loaded(struct kmod_info *kmod, uint32_t flag)
 {
        dtrace_provider_t *prv;
 
+       /*
+        * If kernel symbols have been disabled, return immediately
+        * DTRACE_KERNEL_SYMBOLS_NEVER is a permanent mode, it is safe to test without holding locks
+        */
+       if (dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_NEVER)
+               return 0;
+       
+       struct modctl *ctl = NULL;
+       if (!kmod || kmod->address == 0 || kmod->size == 0)
+               return(-1);
+               
        lck_mtx_lock(&dtrace_provider_lock);
-       lck_mtx_lock(&mod_lock);
+       lck_mtx_lock(&mod_lock);        
+       
+       /*
+        * Have we seen this kext before?
+        */
 
-       // ASSERT(ctl->mod_busy);
+       ctl = dtrace_modctl_lookup(kmod);
+
+       if (ctl != NULL) {
+               /* bail... we already have this kext in the modctl list */
+               lck_mtx_unlock(&mod_lock);
+               lck_mtx_unlock(&dtrace_provider_lock);
+               if (dtrace_err_verbose)
+                       cmn_err(CE_WARN, "dtrace load module already exists '%s %u' is failing against '%s %u'", kmod->name, (uint_t)kmod->id, ctl->mod_modname, ctl->mod_id);
+               return(-1);
+       }
+       else {
+               ctl = kmem_alloc(sizeof(struct modctl), KM_SLEEP);
+               if (ctl == NULL) {
+                       if (dtrace_err_verbose)
+                               cmn_err(CE_WARN, "dtrace module load '%s %u' is failing ", kmod->name, (uint_t)kmod->id);
+                       lck_mtx_unlock(&mod_lock);
+                       lck_mtx_unlock(&dtrace_provider_lock);
+                       return (-1);
+               }
+               ctl->mod_next = NULL;
+               ctl->mod_stale = NULL;
+               strlcpy (ctl->mod_modname, kmod->name, sizeof(ctl->mod_modname));
+               ctl->mod_loadcnt = kmod->id;
+               ctl->mod_nenabled = 0;
+               ctl->mod_address  = kmod->address;
+               ctl->mod_size = kmod->size;
+               ctl->mod_id = kmod->id;
+               ctl->mod_loaded = 1;
+               ctl->mod_flags = 0;
+               ctl->mod_user_symbols = NULL;
+               
+               /*
+                * Find the UUID for this module, if it has one
+                */
+               kernel_mach_header_t* header = (kernel_mach_header_t *)ctl->mod_address;
+               struct load_command* load_cmd = (struct load_command *)&header[1];
+               uint32_t i;
+               for (i = 0; i < header->ncmds; i++) {
+                       if (load_cmd->cmd == LC_UUID) {
+                               struct uuid_command* uuid_cmd = (struct uuid_command *)load_cmd;
+                               memcpy(ctl->mod_uuid, uuid_cmd->uuid, sizeof(uuid_cmd->uuid));
+                               ctl->mod_flags |= MODCTL_HAS_UUID;
+                               break;
+                       }
+                       load_cmd = (struct load_command *)((caddr_t)load_cmd + load_cmd->cmdsize);
+               }
+               
+               if (ctl->mod_address == g_kernel_kmod_info.address) {
+                       ctl->mod_flags |= MODCTL_IS_MACH_KERNEL;
+               }
+       }
+       dtrace_modctl_add(ctl);
+       
+       /*
+        * We must hold the dtrace_lock to safely test non permanent dtrace_fbt_symbol_mode(s)
+        */
+       lck_mtx_lock(&dtrace_lock);
+       
+       /*
+        * DTrace must decide if it will instrument modules lazily via
+        * userspace symbols (default mode), or instrument immediately via 
+        * kernel symbols (non-default mode)
+        *
+        * When in default/lazy mode, DTrace will only support modules
+        * built with a valid UUID.
+        *
+        * Overriding the default can be done explicitly in one of
+        * the following two ways.
+        *
+        * A module can force symbols from kernel space using the plist key,
+        * OSBundleForceDTraceInit (see kmod.h).  If this per kext state is set,
+        * we fall through and instrument this module now.
+        *
+        * Or, the boot-arg, dtrace_kernel_symbol_mode, can be set to force symbols
+        * from kernel space (see dtrace_impl.h).  If this system state is set
+        * to a non-userspace mode, we fall through and instrument the module now.
+        */
 
+       if ((dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_FROM_USERSPACE) &&
+           (!(flag & KMOD_DTRACE_FORCE_INIT)))
+       {
+               /* We will instrument the module lazily -- this is the default */
+               lck_mtx_unlock(&dtrace_lock);
+               lck_mtx_unlock(&mod_lock);
+               lck_mtx_unlock(&dtrace_provider_lock);
+               return 0;
+       }
+       
+       /* We will instrument the module immediately using kernel symbols */
+       ctl->mod_flags |= MODCTL_HAS_KERNEL_SYMBOLS;
+       
+       lck_mtx_unlock(&dtrace_lock);
+       
        /*
         * We're going to call each providers per-module provide operation
         * specifying only this module.
         */
        for (prv = dtrace_provider; prv != NULL; prv = prv->dtpv_next)
-               prv->dtpv_pops.dtps_provide_module(prv->dtpv_arg, ctl);
-
+               prv->dtpv_pops.dtps_provide_module(prv->dtpv_arg, ctl); 
+       
+       /*
+        * APPLE NOTE: The contract with the kext loader is that once this function
+        * has completed, it may delete kernel symbols at will.
+        * We must set this while still holding the mod_lock.
+        */
+       ctl->mod_flags &= ~MODCTL_HAS_KERNEL_SYMBOLS;
+       
        lck_mtx_unlock(&mod_lock);
        lck_mtx_unlock(&dtrace_provider_lock);
-
+       
        /*
         * If we have any retained enablings, we need to match against them.
         * Enabling probes requires that cpu_lock be held, and we cannot hold
@@ -14547,60 +15254,106 @@ dtrace_module_loaded(struct modctl *ctl)
         * our task queue to do the match for us.
         */
        lck_mtx_lock(&dtrace_lock);
-
+       
        if (dtrace_retained == NULL) {
                lck_mtx_unlock(&dtrace_lock);
-               return;
+               return 0;
        }
-
-       (void) taskq_dispatch(dtrace_taskq,
-           (task_func_t *)dtrace_enabling_matchall, NULL, TQ_SLEEP);
-
-       lck_mtx_unlock(&dtrace_lock);
-
-       /*
-        * And now, for a little heuristic sleaze:  in general, we want to
-        * match modules as soon as they load.  However, we cannot guarantee
-        * this, because it would lead us to the lock ordering violation
-        * outlined above.  The common case, of course, is that cpu_lock is
-        * _not_ held -- so we delay here for a clock tick, hoping that that's
-        * long enough for the task queue to do its work.  If it's not, it's
-        * not a serious problem -- it just means that the module that we
-        * just loaded may not be immediately instrumentable.
+       
+       /* APPLE NOTE!
+        *
+        * The cpu_lock mentioned above is only held by dtrace code, Apple's xnu never actually
+        * holds it for any reason. Thus the comment above is invalid, we can directly invoke
+        * dtrace_enabling_matchall without jumping through all the hoops, and we can avoid
+        * the delay call as well.
         */
-       delay(1);
+       lck_mtx_unlock(&dtrace_lock);
+       
+       dtrace_enabling_matchall();
+       
+       return 0;
 }
 
-static void
-dtrace_module_unloaded(struct modctl *ctl)
+/*
+ * Return 0 on success
+ * Return -1 on failure
+ */
+static int
+dtrace_module_unloaded(struct kmod_info *kmod)
 {
        dtrace_probe_t template, *probe, *first, *next;
        dtrace_provider_t *prov;
-
-       template.dtpr_mod = ctl->mod_modname;
-
-       lck_mtx_lock(&dtrace_provider_lock);
+        struct modctl *ctl = NULL;
+       struct modctl *syncctl = NULL;
+       struct modctl *nextsyncctl = NULL;
+       int syncmode = 0;
+       
+        lck_mtx_lock(&dtrace_provider_lock);
        lck_mtx_lock(&mod_lock);
        lck_mtx_lock(&dtrace_lock);
 
+       if (kmod == NULL) {
+           syncmode = 1;
+       }
+       else {
+           ctl = dtrace_modctl_lookup(kmod);
+           if (ctl == NULL)
+           {
+               lck_mtx_unlock(&dtrace_lock);
+               lck_mtx_unlock(&mod_lock);
+               lck_mtx_unlock(&dtrace_provider_lock);
+               return (-1);
+           }
+           ctl->mod_loaded = 0;
+           ctl->mod_address = 0;
+           ctl->mod_size = 0;
+       }
+       
        if (dtrace_bymod == NULL) {
                /*
                 * The DTrace module is loaded (obviously) but not attached;
                 * we don't have any work to do.
                 */
-               lck_mtx_unlock(&dtrace_provider_lock);
-               lck_mtx_unlock(&mod_lock);
+                if (ctl != NULL)
+                        (void)dtrace_modctl_remove(ctl);
+                lck_mtx_unlock(&dtrace_lock);
+                lck_mtx_unlock(&mod_lock);
+                lck_mtx_unlock(&dtrace_provider_lock);
+                return(0);
+       }
+
+       /* Syncmode set means we target and traverse entire modctl list. */
+        if (syncmode)
+           nextsyncctl = dtrace_modctl_list;
+
+syncloop:
+       if (syncmode)
+       {
+           /* find a stale modctl struct */
+           for (syncctl = nextsyncctl; syncctl != NULL; syncctl=syncctl->mod_next) {
+               if (syncctl->mod_address == 0)
+                   break;
+           }
+           if (syncctl==NULL)
+           {
+               /* We have no more work to do */
                lck_mtx_unlock(&dtrace_lock);
-               return;
+               lck_mtx_unlock(&mod_lock);
+               lck_mtx_unlock(&dtrace_provider_lock);
+               return(0);
+           }
+           else {
+               /* keep track of next syncctl in case this one is removed */
+               nextsyncctl = syncctl->mod_next;
+               ctl = syncctl;
+           }
        }
 
+       template.dtpr_mod = ctl->mod_modname;
+       
        for (probe = first = dtrace_hash_lookup(dtrace_bymod, &template);
            probe != NULL; probe = probe->dtpr_nextmod) {
-               if (probe->dtpr_ecb != NULL) {
-                       lck_mtx_unlock(&dtrace_provider_lock);
-                       lck_mtx_unlock(&mod_lock);
-                       lck_mtx_unlock(&dtrace_lock);
-
+               if (probe->dtpr_ecb != NULL) {
                        /*
                         * This shouldn't _actually_ be possible -- we're
                         * unloading a module that has an enabled probe in it.
@@ -14611,12 +15364,22 @@ dtrace_module_unloaded(struct modctl *ctl)
                         * assert, but we're not going to disable the
                         * probe, either.
                         */
+
+
+                       if (syncmode) {
+                           /* We're syncing, let's look at next in list */
+                           goto syncloop;
+                       }
+
+                       lck_mtx_unlock(&dtrace_lock);
+                       lck_mtx_unlock(&mod_lock);
+                       lck_mtx_unlock(&dtrace_provider_lock);
+                   
                        if (dtrace_err_verbose) {
                                cmn_err(CE_WARN, "unloaded module '%s' had "
                                    "enabled probes", ctl->mod_modname);
                        }
-
-                       return;
+                       return(-1);
                }
        }
 
@@ -14626,6 +15389,7 @@ dtrace_module_unloaded(struct modctl *ctl)
                ASSERT(dtrace_probes[probe->dtpr_id - 1] == probe);
 
                dtrace_probes[probe->dtpr_id - 1] = NULL;
+               probe->dtpr_provider->dtpv_probe_count--;                                       
 
                next = probe->dtpr_nextmod;
                dtrace_hash_remove(dtrace_bymod, probe);
@@ -14657,16 +15421,20 @@ dtrace_module_unloaded(struct modctl *ctl)
                kmem_free(probe->dtpr_func, strlen(probe->dtpr_func) + 1);
                kmem_free(probe->dtpr_name, strlen(probe->dtpr_name) + 1);
                vmem_free(dtrace_arena, (void *)(uintptr_t)probe->dtpr_id, 1);
-#if !defined(__APPLE__)
-               kmem_free(probe, sizeof (dtrace_probe_t));
-#else
+
                zfree(dtrace_probe_t_zone, probe);
-#endif
        }
 
+       dtrace_modctl_remove(ctl);
+       
+       if (syncmode)
+           goto syncloop;
+
        lck_mtx_unlock(&dtrace_lock);
        lck_mtx_unlock(&mod_lock);
        lck_mtx_unlock(&dtrace_provider_lock);
+
+       return(0);
 }
 
 void
@@ -14775,8 +15543,8 @@ dtrace_toxrange_add(uintptr_t base, uintptr_t limit)
                dtrace_toxrange = range;
        }
 
-       ASSERT(dtrace_toxrange[dtrace_toxranges].dtt_base == NULL);
-       ASSERT(dtrace_toxrange[dtrace_toxranges].dtt_limit == NULL);
+       ASSERT(dtrace_toxrange[dtrace_toxranges].dtt_base == 0);
+       ASSERT(dtrace_toxrange[dtrace_toxranges].dtt_limit == 0);
 
        dtrace_toxrange[dtrace_toxranges].dtt_base = base;
        dtrace_toxrange[dtrace_toxranges].dtt_limit = limit;
@@ -14790,6 +15558,7 @@ dtrace_toxrange_add(uintptr_t base, uintptr_t limit)
 static int
 dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
 {
+#pragma unused(cmd) /* __APPLE__ */
        dtrace_provider_id_t id;
        dtrace_state_t *state = NULL;
        dtrace_enabling_t *enab;
@@ -14801,26 +15570,13 @@ dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
        if (ddi_soft_state_init(&dtrace_softstate,
            sizeof (dtrace_state_t), 0) != 0) {
                cmn_err(CE_NOTE, "/dev/dtrace failed to initialize soft state");
-               lck_mtx_unlock(&cpu_lock);
-               lck_mtx_unlock(&dtrace_provider_lock);
                lck_mtx_unlock(&dtrace_lock);
-               return (DDI_FAILURE);
-       }
-
-#if !defined(__APPLE__)
-       if (ddi_create_minor_node(devi, DTRACEMNR_DTRACE, S_IFCHR,
-           DTRACEMNRN_DTRACE, DDI_PSEUDO, NULL) == DDI_FAILURE ||
-           ddi_create_minor_node(devi, DTRACEMNR_HELPER, S_IFCHR,
-           DTRACEMNRN_HELPER, DDI_PSEUDO, NULL) == DDI_FAILURE) {
-               cmn_err(CE_NOTE, "/dev/dtrace couldn't create minor nodes");
-               ddi_remove_minor_node(devi, NULL);
-               ddi_soft_state_fini(&dtrace_softstate);
-               lck_mtx_unlock(&cpu_lock);
                lck_mtx_unlock(&dtrace_provider_lock);
-               lck_mtx_unlock(&dtrace_lock);
+               lck_mtx_unlock(&cpu_lock);
                return (DDI_FAILURE);
        }
-#endif /* __APPLE__ */
+
+       /* Darwin uses BSD cloning device driver to automagically obtain minor device number. */
 
        ddi_report_dev(devi);
        dtrace_devi = devi;
@@ -14834,8 +15590,6 @@ dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
        dtrace_cpustart_fini = dtrace_resume;
        dtrace_debugger_init = dtrace_suspend;
        dtrace_debugger_fini = dtrace_resume;
-       dtrace_kreloc_init = dtrace_suspend;
-       dtrace_kreloc_fini = dtrace_resume;
 
        register_cpu_setup_func((cpu_setup_func_t *)dtrace_cpu_setup, NULL);
 
@@ -14854,7 +15608,6 @@ dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
            NULL, NULL, NULL, NULL, NULL, 0);
 
        lck_mtx_assert(&cpu_lock, LCK_MTX_ASSERT_OWNED);
-
        dtrace_bymod = dtrace_hash_create(offsetof(dtrace_probe_t, dtpr_mod),
            offsetof(dtrace_probe_t, dtpr_nextmod),
            offsetof(dtrace_probe_t, dtpr_prevmod));
@@ -14891,21 +15644,7 @@ dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
        ASSERT(dtrace_provider != NULL);
        ASSERT((dtrace_provider_id_t)dtrace_provider == id);
 
-#if !defined(__APPLE__)
-       dtrace_probeid_begin = dtrace_probe_create((dtrace_provider_id_t)
-           dtrace_provider, NULL, NULL, "BEGIN", 0, NULL);
-       dtrace_probeid_end = dtrace_probe_create((dtrace_provider_id_t)
-           dtrace_provider, NULL, NULL, "END", 0, NULL);
-       dtrace_probeid_error = dtrace_probe_create((dtrace_provider_id_t)
-           dtrace_provider, NULL, NULL, "ERROR", 1, NULL);
-#elif defined(__ppc__) || defined(__ppc64__)
-       dtrace_probeid_begin = dtrace_probe_create((dtrace_provider_id_t)
-           dtrace_provider, NULL, NULL, "BEGIN", 2, NULL);
-       dtrace_probeid_end = dtrace_probe_create((dtrace_provider_id_t)
-           dtrace_provider, NULL, NULL, "END", 1, NULL);
-       dtrace_probeid_error = dtrace_probe_create((dtrace_provider_id_t)
-           dtrace_provider, NULL, NULL, "ERROR", 4, NULL);
-#elif (defined(__i386__) || defined (__x86_64__))
+#if defined (__x86_64__)
        dtrace_probeid_begin = dtrace_probe_create((dtrace_provider_id_t)
            dtrace_provider, NULL, NULL, "BEGIN", 1, NULL);
        dtrace_probeid_end = dtrace_probe_create((dtrace_provider_id_t)
@@ -14914,7 +15653,7 @@ dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
            dtrace_provider, NULL, NULL, "ERROR", 3, NULL);
 #else
 #error Unknown Architecture
-#endif /* __APPLE__ */
+#endif
 
        dtrace_anon_property();
        lck_mtx_unlock(&cpu_lock);
@@ -14940,6 +15679,13 @@ dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
        if (dtrace_anon.dta_enabling != NULL) {
                ASSERT(dtrace_retained == dtrace_anon.dta_enabling);
 
+               /*
+                * APPLE NOTE: if handling anonymous dof, switch symbol modes.
+                */
+               if (dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_FROM_USERSPACE) {
+                       dtrace_kernel_symbol_mode = DTRACE_KERNEL_SYMBOLS_FROM_KERNEL;
+               }
+               
                dtrace_enabling_provide(NULL);
                state = dtrace_anon.dta_state;
 
@@ -14976,8 +15722,6 @@ dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
        return (DDI_SUCCESS);
 }
 
-extern void fasttrap_init(void);
-
 /*ARGSUSED*/
 static int
 dtrace_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
@@ -14987,19 +15731,9 @@ dtrace_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
        uint32_t priv;
        uid_t uid;
        zoneid_t zoneid;
+       int rv;
 
-#if !defined(__APPLE__)
-       if (getminor(*devp) == DTRACEMNRN_HELPER)
-               return (0);
-
-       /*
-        * If this wasn't an open with the "helper" minor, then it must be
-        * the "dtrace" minor.
-        */
-       ASSERT(getminor(*devp) == DTRACEMNRN_DTRACE);
-#else
-       /* Darwin puts Helper on its own major device. */
-#endif /* __APPLE__ */
+       /* APPLE: Darwin puts Helper on its own major device. */
 
        /*
         * If no DTRACE_PRIV_* bits are set in the credential, then the
@@ -15009,13 +15743,11 @@ dtrace_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
        if (priv == DTRACE_PRIV_NONE)
                return (EACCES);
 
-#if defined(__APPLE__)
        /*
-        * We delay the initialization of fasttrap as late as possible.
+        * APPLE NOTE: We delay the initialization of fasttrap as late as possible.
         * It certainly can't be later than now!
         */
        fasttrap_init();
-#endif /* __APPLE__ */
 
        /*
         * Ask all providers to provide all their probes.
@@ -15035,24 +15767,24 @@ dtrace_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
         */
        if (kdi_dtrace_set(KDI_DTSET_DTRACE_ACTIVATE) != 0) {
                dtrace_opens--;
-               lck_mtx_unlock(&cpu_lock);
                lck_mtx_unlock(&dtrace_lock);
+               lck_mtx_unlock(&cpu_lock);
                return (EBUSY);
        }
 
-       state = dtrace_state_create(devp, cred_p);
+       rv = dtrace_state_create(devp, cred_p, &state);
        lck_mtx_unlock(&cpu_lock);
 
-       if (state == NULL) {
-               if (--dtrace_opens == 0)
+       if (rv != 0 || state == NULL) {
+               if (--dtrace_opens == 0 && dtrace_anon.dta_enabling == NULL)
                        (void) kdi_dtrace_set(KDI_DTSET_DTRACE_DEACTIVATE);
                lck_mtx_unlock(&dtrace_lock);
-               return (EAGAIN);
+               /* propagate EAGAIN or ERESTART */
+               return (rv);
        }
-
+       
        lck_mtx_unlock(&dtrace_lock);
 
-#if defined(__APPLE__)
        lck_rw_lock_exclusive(&dtrace_dof_mode_lock);
 
        /*
@@ -15076,7 +15808,27 @@ dtrace_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
        }
 
        lck_rw_unlock_exclusive(&dtrace_dof_mode_lock);
-#endif
+
+       /*
+        * Update kernel symbol state.
+        *
+        * We must own the provider and dtrace locks. 
+        *
+        * NOTE! It may appear there is a race by setting this value so late
+        * after dtrace_probe_provide. However, any kext loaded after the
+        * call to probe provide and before we set LAZY_OFF will be marked as
+        * eligible for symbols from userspace. The same dtrace that is currently
+        * calling dtrace_open() (this call!) will get a list of kexts needing
+        * symbols and fill them in, thus closing the race window.
+        *
+        * We want to set this value only after it certain it will succeed, as
+        * this significantly reduces the complexity of error exits.
+        */
+       lck_mtx_lock(&dtrace_lock);
+       if (dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_FROM_USERSPACE) {
+               dtrace_kernel_symbol_mode = DTRACE_KERNEL_SYMBOLS_FROM_KERNEL;
+       }
+       lck_mtx_unlock(&dtrace_lock);
 
        return (0);
 }
@@ -15085,16 +15837,11 @@ dtrace_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
 static int
 dtrace_close(dev_t dev, int flag, int otyp, cred_t *cred_p)
 {
-#pragma unused(flag,otyp,cred_p)
+#pragma unused(flag, otyp, cred_p) /* __APPLE__ */
        minor_t minor = getminor(dev);
        dtrace_state_t *state;
 
-#if !defined(__APPLE__)
-       if (minor == DTRACEMNRN_HELPER)
-               return (0);
-#else
-       /* Darwin puts Helper on its own major device. */
-#endif /* __APPLE__ */
+       /* APPLE NOTE: Darwin puts Helper on its own major device. */
 
        state = ddi_get_soft_state(dtrace_softstate, minor);
 
@@ -15111,49 +15858,58 @@ dtrace_close(dev_t dev, int flag, int otyp, cred_t *cred_p)
 
        dtrace_state_destroy(state);
        ASSERT(dtrace_opens > 0);
-       if (--dtrace_opens == 0)
-               (void) kdi_dtrace_set(KDI_DTSET_DTRACE_DEACTIVATE);
 
+       /*
+        * Only relinquish control of the kernel debugger interface when there
+        * are no consumers and no anonymous enablings.
+        */
+       if (--dtrace_opens == 0 && dtrace_anon.dta_enabling == NULL)
+               (void) kdi_dtrace_set(KDI_DTSET_DTRACE_DEACTIVATE);
+       
        lck_mtx_unlock(&dtrace_lock);
        lck_mtx_unlock(&cpu_lock);
 
-#if defined(__APPLE__)
-
        /*
         * Lock ordering requires the dof mode lock be taken before
         * the dtrace_lock.
         */
        lck_rw_lock_exclusive(&dtrace_dof_mode_lock);
        lck_mtx_lock(&dtrace_lock);
+       
+       if (dtrace_opens == 0) {
+               /*
+                * If we are currently lazy-off, and this is the last close, transition to
+                * lazy state.
+                */
+               if (dtrace_dof_mode == DTRACE_DOF_MODE_LAZY_OFF) {
+                       dtrace_dof_mode = DTRACE_DOF_MODE_LAZY_ON;
+               }
 
-       /*
-        * If we are currently lazy-off, and this is the last close, transition to
-        * lazy state.
-        */
-       if (dtrace_dof_mode == DTRACE_DOF_MODE_LAZY_OFF && dtrace_opens == 0) {
-               dtrace_dof_mode = DTRACE_DOF_MODE_LAZY_ON;
+               /*
+                * If we are the last dtrace client, switch back to lazy (from userspace) symbols
+                */
+               if (dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_FROM_KERNEL) {
+                       dtrace_kernel_symbol_mode = DTRACE_KERNEL_SYMBOLS_FROM_USERSPACE;
+               }
        }
-
+       
        lck_mtx_unlock(&dtrace_lock);
        lck_rw_unlock_exclusive(&dtrace_dof_mode_lock);
-#endif
+       
+       /*
+        * Kext probes may be retained past the end of the kext's lifespan. The
+        * probes are kept until the last reference to them has been removed.
+        * Since closing an active dtrace context is likely to drop that last reference,
+        * lets take a shot at cleaning out the orphaned probes now.
+        */
+       dtrace_module_unloaded(NULL);
 
        return (0);
 }
 
-#if defined(__APPLE__)
-/*
- * Introduce cast to quiet warnings.
- * XXX: This hides a lot of brokenness.
- */
-#define copyin(src, dst, len) copyin( (user_addr_t)(src), (dst), (len) )
-#define copyout(src, dst, len) copyout( (src), (user_addr_t)(dst), (len) )
-#endif /* __APPLE__ */
-
-#if defined(__APPLE__)
 /*ARGSUSED*/
 static int
-dtrace_ioctl_helper(int cmd, caddr_t arg, int *rv)
+dtrace_ioctl_helper(u_long cmd, caddr_t arg, int *rv)
 {
 #pragma unused(rv)
        /*
@@ -15163,7 +15919,8 @@ dtrace_ioctl_helper(int cmd, caddr_t arg, int *rv)
                return KERN_SUCCESS;
 
        switch (cmd) {
-               case DTRACEHIOC_ADDDOF: {
+       case DTRACEHIOC_ADDDOF:
+                       {
                        dof_helper_t *dhp = NULL;
                        size_t dof_ioctl_data_size;
                        dof_ioctl_data_t* multi_dof;
@@ -15299,30 +16056,23 @@ dtrace_ioctl_helper(int cmd, caddr_t arg, int *rv)
 
        return ENOTTY;
 }
-#endif /* __APPLE__ */
 
 /*ARGSUSED*/
 static int
-dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
+dtrace_ioctl(dev_t dev, u_long cmd, user_addr_t arg, int md, cred_t *cr, int *rv)
 {
 #pragma unused(md)
-
        minor_t minor = getminor(dev);
        dtrace_state_t *state;
        int rval;
 
-#if !defined(__APPLE__)
-       if (minor == DTRACEMNRN_HELPER)
-               return (dtrace_ioctl_helper(cmd, arg, rv));
-#else
        /* Darwin puts Helper on its own major device. */
-#endif /* __APPLE__ */
 
        state = ddi_get_soft_state(dtrace_softstate, minor);
 
        if (state->dts_anon) {
-               ASSERT(dtrace_anon.dta_state == NULL);
-               state = state->dts_anon;
+          ASSERT(dtrace_anon.dta_state == NULL);
+          state = state->dts_anon;
        }
 
        switch (cmd) {
@@ -15330,14 +16080,14 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                dtrace_providerdesc_t pvd;
                dtrace_provider_t *pvp;
 
-               if (copyin((void *)arg, &pvd, sizeof (pvd)) != 0)
+               if (copyin(arg, &pvd, sizeof (pvd)) != 0)
                        return (EFAULT);
 
                pvd.dtvd_name[DTRACE_PROVNAMELEN - 1] = '\0';
                lck_mtx_lock(&dtrace_provider_lock);
 
                for (pvp = dtrace_provider; pvp != NULL; pvp = pvp->dtpv_next) {
-                       if (strcmp(pvp->dtpv_name, pvd.dtvd_name) == 0)
+                       if (strncmp(pvp->dtpv_name, pvd.dtvd_name, DTRACE_PROVNAMELEN) == 0)
                                break;
                }
 
@@ -15348,7 +16098,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
 
                bcopy(&pvp->dtpv_priv, &pvd.dtvd_priv, sizeof (dtrace_ppriv_t));
                bcopy(&pvp->dtpv_attr, &pvd.dtvd_attr, sizeof (dtrace_pattr_t));
-               if (copyout(&pvd, (void *)arg, sizeof (pvd)) != 0)
+               if (copyout(&pvd, arg, sizeof (pvd)) != 0)
                        return (EFAULT);
 
                return (0);
@@ -15363,7 +16113,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                uintptr_t dest;
                int nrecs;
 
-               if (copyin((void *)arg, &epdesc, sizeof (epdesc)) != 0)
+               if (copyin(arg, &epdesc, sizeof (epdesc)) != 0)
                        return (EFAULT);
 
                lck_mtx_lock(&dtrace_lock);
@@ -15398,7 +16148,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                 * across the copyout(), below.
                 */
                size = sizeof (dtrace_eprobedesc_t) +
-                   (epdesc.dtepd_nrecs * sizeof (dtrace_recdesc_t));
+                       (epdesc.dtepd_nrecs * sizeof (dtrace_recdesc_t));
 
                buf = kmem_alloc(size, KM_SLEEP);
                dest = (uintptr_t)buf;
@@ -15414,13 +16164,13 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                                break;
 
                        bcopy(&act->dta_rec, (void *)dest,
-                           sizeof (dtrace_recdesc_t));
+                       sizeof (dtrace_recdesc_t));
                        dest += sizeof (dtrace_recdesc_t);
                }
 
                lck_mtx_unlock(&dtrace_lock);
 
-               if (copyout(buf, (void *)arg, dest - (uintptr_t)buf) != 0) {
+               if (copyout(buf, arg, dest - (uintptr_t)buf) != 0) {
                        kmem_free(buf, size);
                        return (EFAULT);
                }
@@ -15440,7 +16190,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                size_t size;
                uintptr_t dest;
 
-               if (copyin((void *)arg, &aggdesc, sizeof (aggdesc)) != 0)
+               if (copyin(arg, &aggdesc, sizeof (aggdesc)) != 0)
                        return (EFAULT);
 
                lck_mtx_lock(&dtrace_lock);
@@ -15461,7 +16211,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
 
                for (act = agg->dtag_first; ; act = act->dta_next) {
                        ASSERT(act->dta_intuple ||
-                           DTRACEACT_ISAGG(act->dta_kind));
+                       DTRACEACT_ISAGG(act->dta_kind));
 
                        /*
                         * If this action has a record size of zero, it
@@ -15489,7 +16239,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                 * across the copyout(), below.
                 */
                size = sizeof (dtrace_aggdesc_t) +
-                   (aggdesc.dtagd_nrecs * sizeof (dtrace_recdesc_t));
+                       (aggdesc.dtagd_nrecs * sizeof (dtrace_recdesc_t));
 
                buf = kmem_alloc(size, KM_SLEEP);
                dest = (uintptr_t)buf;
@@ -15522,7 +16272,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
 
                lck_mtx_unlock(&dtrace_lock);
 
-               if (copyout(buf, (void *)arg, dest - (uintptr_t)buf) != 0) {
+               if (copyout(buf, arg, dest - (uintptr_t)buf) != 0) {
                        kmem_free(buf, size);
                        return (EFAULT);
                }
@@ -15543,14 +16293,10 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                 * If a NULL argument has been passed, we take this as our
                 * cue to reevaluate our enablings.
                 */
-               if (arg == NULL) {
-                       lck_mtx_lock(&cpu_lock);
-                       lck_mtx_lock(&dtrace_lock);
-                       err = dtrace_enabling_matchstate(state, rv);
-                       lck_mtx_unlock(&dtrace_lock);
-                       lck_mtx_unlock(&cpu_lock);
+               if (arg == 0) {
+                       dtrace_enabling_matchall();
 
-                       return (err);
+                       return (0);
                }
 
                if ((dof = dtrace_dof_copyin(arg, &rval)) == NULL)
@@ -15588,8 +16334,8 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                        dtrace_enabling_destroy(enab);
                }
 
-               lck_mtx_unlock(&cpu_lock);
                lck_mtx_unlock(&dtrace_lock);
+               lck_mtx_unlock(&cpu_lock);
                dtrace_dof_destroy(dof);
 
                return (err);
@@ -15601,7 +16347,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                dtrace_probedesc_t *create = &desc.dtrpd_create;
                int err;
 
-               if (copyin((void *)arg, &desc, sizeof (desc)) != 0)
+               if (copyin(arg, &desc, sizeof (desc)) != 0)
                        return (EFAULT);
 
                match->dtpd_provider[DTRACE_PROVNAMELEN - 1] = '\0';
@@ -15632,7 +16378,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                uid_t uid;
                zoneid_t zoneid;
 
-               if (copyin((void *)arg, &desc, sizeof (desc)) != 0)
+               if (copyin(arg, &desc, sizeof (desc)) != 0)
                        return (EFAULT);
 
                desc.dtpd_provider[DTRACE_PROVNAMELEN - 1] = '\0';
@@ -15661,10 +16407,11 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                lck_mtx_lock(&dtrace_lock);
 
                if (cmd == DTRACEIOC_PROBEMATCH) {
-                       for (i = desc.dtpd_id; i <= dtrace_nprobes; i++) {
+                        /* Quiet compiler warning */
+                       for (i = desc.dtpd_id; i <= (dtrace_id_t)dtrace_nprobes; i++) {
                                if ((probe = dtrace_probes[i - 1]) != NULL &&
-                                   (m = dtrace_match_probe(probe, &pkey,
-                                   priv, uid, zoneid)) != 0)
+                                       (m = dtrace_match_probe(probe, &pkey,
+                                       priv, uid, zoneid)) != 0)
                                        break;
                        }
 
@@ -15674,9 +16421,10 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                        }
 
                } else {
-                       for (i = desc.dtpd_id; i <= dtrace_nprobes; i++) {
+                        /* Quiet compiler warning */
+                       for (i = desc.dtpd_id; i <= (dtrace_id_t)dtrace_nprobes; i++) {
                                if ((probe = dtrace_probes[i - 1]) != NULL &&
-                                   dtrace_match_priv(probe, priv, uid, zoneid))
+                                       dtrace_match_priv(probe, priv, uid, zoneid))
                                        break;
                        }
                }
@@ -15689,7 +16437,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                dtrace_probe_description(probe, &desc);
                lck_mtx_unlock(&dtrace_lock);
 
-               if (copyout(&desc, (void *)arg, sizeof (desc)) != 0)
+               if (copyout(&desc, arg, sizeof (desc)) != 0)
                        return (EFAULT);
 
                return (0);
@@ -15700,7 +16448,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                dtrace_probe_t *probe;
                dtrace_provider_t *prov;
 
-               if (copyin((void *)arg, &desc, sizeof (desc)) != 0)
+               if (copyin(arg, &desc, sizeof (desc)) != 0)
                        return (EFAULT);
 
                if (desc.dtargd_id == DTRACE_IDNONE)
@@ -15713,7 +16461,8 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                lck_mtx_lock(&mod_lock);
                lck_mtx_lock(&dtrace_lock);
 
-               if (desc.dtargd_id > dtrace_nprobes) {
+                /* Quiet compiler warning */
+               if (desc.dtargd_id > (dtrace_id_t)dtrace_nprobes) {
                        lck_mtx_unlock(&dtrace_lock);
                        lck_mtx_unlock(&mod_lock);
                        lck_mtx_unlock(&dtrace_provider_lock);
@@ -15732,10 +16481,10 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                prov = probe->dtpr_provider;
 
                if (prov->dtpv_pops.dtps_getargdesc == NULL) {
-                       /*
-                        * There isn't any typed information for this probe.
-                        * Set the argument number to DTRACE_ARGNONE.
-                        */
+               /*
+                * There isn't any typed information for this probe.
+                * Set the argument number to DTRACE_ARGNONE.
+                */
                        desc.dtargd_ndx = DTRACE_ARGNONE;
                } else {
                        desc.dtargd_native[0] = '\0';
@@ -15743,13 +16492,13 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                        desc.dtargd_mapping = desc.dtargd_ndx;
 
                        prov->dtpv_pops.dtps_getargdesc(prov->dtpv_arg,
-                           probe->dtpr_id, probe->dtpr_arg, &desc);
+                       probe->dtpr_id, probe->dtpr_arg, &desc);
                }
 
                lck_mtx_unlock(&mod_lock);
                lck_mtx_unlock(&dtrace_provider_lock);
 
-               if (copyout(&desc, (void *)arg, sizeof (desc)) != 0)
+               if (copyout(&desc, arg, sizeof (desc)) != 0)
                        return (EFAULT);
 
                return (0);
@@ -15762,7 +16511,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                if (rval != 0)
                        return (rval);
 
-               if (copyout(&cpuid, (void *)arg, sizeof (cpuid)) != 0)
+               if (copyout(&cpuid, arg, sizeof (cpuid)) != 0)
                        return (EFAULT);
 
                return (0);
@@ -15778,7 +16527,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                if (rval != 0)
                        return (rval);
 
-               if (copyout(&cpuid, (void *)arg, sizeof (cpuid)) != 0)
+               if (copyout(&cpuid, arg, sizeof (cpuid)) != 0)
                        return (EFAULT);
 
                return (0);
@@ -15788,7 +16537,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                dof_hdr_t hdr, *dof;
                uint64_t len;
 
-               if (copyin((void *)arg, &hdr, sizeof (hdr)) != 0)
+               if (copyin(arg, &hdr, sizeof (hdr)) != 0)
                        return (EFAULT);
 
                lck_mtx_lock(&dtrace_lock);
@@ -15796,7 +16545,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                lck_mtx_unlock(&dtrace_lock);
 
                len = MIN(hdr.dofh_loadsz, dof->dofh_loadsz);
-               rval = copyout(dof, (void *)arg, len);
+               rval = copyout(dof, arg, len);
                dtrace_dof_destroy(dof);
 
                return (rval == 0 ? 0 : EFAULT);
@@ -15808,10 +16557,10 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                caddr_t cached;
                dtrace_buffer_t *buf;
 
-               if (copyin((void *)arg, &desc, sizeof (desc)) != 0)
+               if (copyin(arg, &desc, sizeof (desc)) != 0)
                        return (EFAULT);
 
-               if (desc.dtbd_cpu < 0 || desc.dtbd_cpu >= (int)NCPU)
+               if ((int)desc.dtbd_cpu < 0 || desc.dtbd_cpu >= NCPU)
                        return (EINVAL);
 
                lck_mtx_lock(&dtrace_lock);
@@ -15844,7 +16593,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                                desc.dtbd_oldest = 0;
                                sz = sizeof (desc);
 
-                               if (copyout(&desc, (void *)arg, sz) != 0)
+                               if (copyout(&desc, arg, sz) != 0)
                                        return (EFAULT);
 
                                return (0);
@@ -15859,7 +16608,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                                sz = buf->dtb_size;
                        }
 
-                       if (copyout(buf->dtb_tomax, desc.dtbd_data, sz) != 0) {
+                       if (copyout(buf->dtb_tomax, (user_addr_t)desc.dtbd_data, sz) != 0) {
                                lck_mtx_unlock(&dtrace_lock);
                                return (EFAULT);
                        }
@@ -15871,7 +16620,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
 
                        lck_mtx_unlock(&dtrace_lock);
 
-                       if (copyout(&desc, (void *)arg, sizeof (desc)) != 0)
+                       if (copyout(&desc, arg, sizeof (desc)) != 0)
                                return (EFAULT);
 
                        buf->dtb_flags |= DTRACEBUF_CONSUMED;
@@ -15889,16 +16638,16 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                ASSERT(!(buf->dtb_flags & DTRACEBUF_NOSWITCH));
 
                dtrace_xcall(desc.dtbd_cpu,
-                   (dtrace_xcall_t)dtrace_buffer_switch, buf);
+                       (dtrace_xcall_t)dtrace_buffer_switch, buf);
 
                state->dts_errors += buf->dtb_xamot_errors;
 
                /*
-                * If the buffers did not actually switch, then the cross call
-                * did not take place -- presumably because the given CPU is
-                * not in the ready set.  If this is the case, we'll return
-                * ENOENT.
-                */
+               * If the buffers did not actually switch, then the cross call
+               * did not take place -- presumably because the given CPU is
+               * not in the ready set.  If this is the case, we'll return
+               * ENOENT.
+               */
                if (buf->dtb_tomax == cached) {
                        ASSERT(buf->dtb_xamot != cached);
                        lck_mtx_unlock(&dtrace_lock);
@@ -15908,10 +16657,10 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                ASSERT(cached == buf->dtb_xamot);
 
                /*
-                * We have our snapshot; now copy it out.
-                */
-               if (copyout(buf->dtb_xamot, desc.dtbd_data,
-                   buf->dtb_xamot_offset) != 0) {
+               * We have our snapshot; now copy it out.
+               */
+               if (copyout(buf->dtb_xamot, (user_addr_t)desc.dtbd_data,
+                                       buf->dtb_xamot_offset) != 0) {
                        lck_mtx_unlock(&dtrace_lock);
                        return (EFAULT);
                }
@@ -15926,7 +16675,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                /*
                 * Finally, copy out the buffer description.
                 */
-               if (copyout(&desc, (void *)arg, sizeof (desc)) != 0)
+               if (copyout(&desc, arg, sizeof (desc)) != 0)
                        return (EFAULT);
 
                return (0);
@@ -15941,7 +16690,7 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                conf.dtc_diftupregs = DIF_DTR_NREGS;
                conf.dtc_ctfmodel = CTF_MODEL_NATIVE;
 
-               if (copyout(&conf, (void *)arg, sizeof (conf)) != 0)
+               if (copyout(&conf, arg, sizeof (conf)) != 0)
                        return (EFAULT);
 
                return (0);
@@ -15954,10 +16703,10 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                uint64_t nerrs;
 
                /*
-                * See the comment in dtrace_state_deadman() for the reason
-                * for setting dts_laststatus to INT64_MAX before setting
-                * it to the correct value.
-                */
+               * See the comment in dtrace_state_deadman() for the reason
+               * for setting dts_laststatus to INT64_MAX before setting
+               * it to the correct value.
+               */
                state->dts_laststatus = INT64_MAX;
                dtrace_membar_producer();
                state->dts_laststatus = dtrace_gethrtime();
@@ -16004,12 +16753,12 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                stat.dtst_stkstroverflows = state->dts_stkstroverflows;
                stat.dtst_dblerrors = state->dts_dblerrors;
                stat.dtst_killed =
-                   (state->dts_activity == DTRACE_ACTIVITY_KILLED);
+                       (state->dts_activity == DTRACE_ACTIVITY_KILLED);
                stat.dtst_errors = nerrs;
 
                lck_mtx_unlock(&dtrace_lock);
 
-               if (copyout(&stat, (void *)arg, sizeof (stat)) != 0)
+               if (copyout(&stat, arg, sizeof (stat)) != 0)
                        return (EFAULT);
 
                return (0);
@@ -16020,13 +16769,13 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                char *str;
                int len;
 
-               if (copyin((void *)arg, &fmt, sizeof (fmt)) != 0)
+               if (copyin(arg, &fmt, sizeof (fmt)) != 0)
                        return (EFAULT);
 
                lck_mtx_lock(&dtrace_lock);
 
                if (fmt.dtfd_format == 0 ||
-                   fmt.dtfd_format > state->dts_nformats) {
+                       fmt.dtfd_format > state->dts_nformats) {
                        lck_mtx_unlock(&dtrace_lock);
                        return (EINVAL);
                }
@@ -16046,12 +16795,12 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                if (len > fmt.dtfd_length) {
                        fmt.dtfd_length = len;
 
-                       if (copyout(&fmt, (void *)arg, sizeof (fmt)) != 0) {
+                       if (copyout(&fmt, arg, sizeof (fmt)) != 0) {
                                lck_mtx_unlock(&dtrace_lock);
                                return (EINVAL);
                        }
                } else {
-                       if (copyout(str, fmt.dtfd_string, len) != 0) {
+                       if (copyout(str, (user_addr_t)fmt.dtfd_string, len) != 0) {
                                lck_mtx_unlock(&dtrace_lock);
                                return (EINVAL);
                        }
@@ -16061,6 +16810,312 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
                return (0);
        }
 
+       case DTRACEIOC_MODUUIDSLIST: {
+               size_t module_uuids_list_size;
+               dtrace_module_uuids_list_t* uuids_list;
+               uint64_t dtmul_count;
+
+               /*
+                * Security restrictions make this operation illegal, if this is enabled DTrace
+                * must refuse to provide any fbt probes.
+                */
+               if (dtrace_is_restricted()) {
+                       cmn_err(CE_WARN, "security restrictions disallow DTRACEIOC_MODUUIDSLIST");      
+                       return (EPERM);
+               }
+
+               /*
+                * Fail if the kernel symbol mode makes this operation illegal.
+                * Both NEVER & ALWAYS_FROM_KERNEL are permanent states, it is legal to check
+                * for them without holding the dtrace_lock.
+                */             
+               if (dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_NEVER ||
+                   dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_ALWAYS_FROM_KERNEL) {
+                       cmn_err(CE_WARN, "dtrace_kernel_symbol_mode of %u disallows DTRACEIOC_MODUUIDSLIST", dtrace_kernel_symbol_mode);
+                       return (EPERM);
+               }
+                       
+               /*
+                * Read the number of symbolsdesc structs being passed in.
+                */
+               if (copyin(arg + offsetof(dtrace_module_uuids_list_t, dtmul_count),
+                          &dtmul_count,
+                          sizeof(dtmul_count))) {
+                       cmn_err(CE_WARN, "failed to copyin dtmul_count");
+                       return (EFAULT);
+               }
+               
+               /*
+                * Range check the count. More than 2k kexts is probably an error.
+                */
+               if (dtmul_count > 2048) {
+                       cmn_err(CE_WARN, "dtmul_count is not valid");
+                       return (EINVAL);
+               }
+
+               /*
+                * For all queries, we return EINVAL when the user specified
+                * count does not match the actual number of modules we find
+                * available.
+                *
+                * If the user specified count is zero, then this serves as a
+                * simple query to count the available modules in need of symbols.
+                */
+               
+               rval = 0;
+
+               if (dtmul_count == 0)
+               {
+                       lck_mtx_lock(&mod_lock);
+                       struct modctl* ctl = dtrace_modctl_list;
+                       while (ctl) {
+                               /* Update the private probes bit */
+                               if (dtrace_provide_private_probes)
+                                       ctl->mod_flags |= MODCTL_FBT_PROVIDE_PRIVATE_PROBES;
+
+                               ASSERT(!MOD_HAS_USERSPACE_SYMBOLS(ctl));
+                               if (!MOD_SYMBOLS_DONE(ctl)) {
+                                       dtmul_count++;
+                                       rval = EINVAL;
+                               }
+                               ctl = ctl->mod_next;
+                       }
+                       lck_mtx_unlock(&mod_lock);
+                       
+                       if (copyout(&dtmul_count, arg, sizeof (dtmul_count)) != 0)
+                               return (EFAULT);
+                       else
+                               return (rval);
+               }
+               
+               /*
+                * If we reach this point, then we have a request for full list data.
+                * Allocate a correctly sized structure and copyin the data.
+                */
+               module_uuids_list_size = DTRACE_MODULE_UUIDS_LIST_SIZE(dtmul_count);
+               if ((uuids_list = kmem_alloc(module_uuids_list_size, KM_SLEEP)) == NULL) 
+                       return (ENOMEM);
+               
+               /* NOTE! We can no longer exit this method via return */
+               if (copyin(arg, uuids_list, module_uuids_list_size) != 0) {
+                       cmn_err(CE_WARN, "failed copyin of dtrace_module_uuids_list_t");
+                       rval = EFAULT;
+                       goto moduuidslist_cleanup;
+               }
+               
+               /*
+                * Check that the count didn't change between the first copyin and the second.
+                */
+               if (uuids_list->dtmul_count != dtmul_count) {
+                       rval = EINVAL;
+                       goto moduuidslist_cleanup;
+               }
+               
+               /*
+                * Build the list of UUID's that need symbols
+                */
+               lck_mtx_lock(&mod_lock);
+               
+               dtmul_count = 0;
+               
+               struct modctl* ctl = dtrace_modctl_list;
+               while (ctl) {
+                       /* Update the private probes bit */
+                       if (dtrace_provide_private_probes)
+                               ctl->mod_flags |= MODCTL_FBT_PROVIDE_PRIVATE_PROBES;
+
+                       /*
+                        * We assume that userspace symbols will be "better" than kernel level symbols,
+                        * as userspace can search for dSYM(s) and symbol'd binaries. Even if kernel syms
+                        * are available, add user syms if the module might use them.
+                        */
+                       ASSERT(!MOD_HAS_USERSPACE_SYMBOLS(ctl));
+                       if (!MOD_SYMBOLS_DONE(ctl)) {
+                               UUID* uuid = &uuids_list->dtmul_uuid[dtmul_count];
+                               if (dtmul_count++ < uuids_list->dtmul_count) {
+                                       memcpy(uuid, ctl->mod_uuid, sizeof(UUID));
+                               }
+                       }
+                       ctl = ctl->mod_next;
+               }
+               
+               lck_mtx_unlock(&mod_lock);
+               
+               if (uuids_list->dtmul_count < dtmul_count)
+                       rval = EINVAL;
+               
+               uuids_list->dtmul_count = dtmul_count;
+               
+               /*
+                * Copyout the symbols list (or at least the count!)
+                */
+               if (copyout(uuids_list, arg, module_uuids_list_size) != 0) {
+                       cmn_err(CE_WARN, "failed copyout of dtrace_symbolsdesc_list_t");
+                       rval = EFAULT;
+               }
+               
+       moduuidslist_cleanup:
+               /*
+                * If we had to allocate struct memory, free it.
+                */
+               if (uuids_list != NULL) {
+                       kmem_free(uuids_list, module_uuids_list_size);
+               }
+               
+               return rval;
+       }
+
+       case DTRACEIOC_PROVMODSYMS: {
+               size_t module_symbols_size;
+               dtrace_module_symbols_t* module_symbols;
+               uint64_t dtmodsyms_count;
+
+               /*
+                * Security restrictions make this operation illegal, if this is enabled DTrace
+                * must refuse to provide any fbt probes.
+                */
+               if (dtrace_is_restricted()) {
+                       cmn_err(CE_WARN, "security restrictions disallow DTRACEIOC_MODUUIDSLIST");      
+                       return (EPERM);
+               }
+
+               /*
+                * Fail if the kernel symbol mode makes this operation illegal.
+                * Both NEVER & ALWAYS_FROM_KERNEL are permanent states, it is legal to check
+                * for them without holding the dtrace_lock.
+                */
+               if (dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_NEVER ||
+                   dtrace_kernel_symbol_mode == DTRACE_KERNEL_SYMBOLS_ALWAYS_FROM_KERNEL) {
+                       cmn_err(CE_WARN, "dtrace_kernel_symbol_mode of %u disallows DTRACEIOC_PROVMODSYMS", dtrace_kernel_symbol_mode);
+                       return (EPERM);
+               }
+               
+               /*
+                * Read the number of module symbols structs being passed in.
+                */
+               if (copyin(arg + offsetof(dtrace_module_symbols_t, dtmodsyms_count),
+                          &dtmodsyms_count,
+                          sizeof(dtmodsyms_count))) {
+                       cmn_err(CE_WARN, "failed to copyin dtmodsyms_count");
+                       return (EFAULT);
+               }
+               
+               /*
+                * Range check the count. How much data can we pass around?
+                * FIX ME!
+                */
+               if (dtmodsyms_count == 0 || (dtmodsyms_count > 100 * 1024)) {
+                       cmn_err(CE_WARN, "dtmodsyms_count is not valid");
+                       return (EINVAL);
+               }
+                       
+               /*
+                * Allocate a correctly sized structure and copyin the data.
+                */
+               module_symbols_size = DTRACE_MODULE_SYMBOLS_SIZE(dtmodsyms_count);
+               if ((module_symbols = kmem_alloc(module_symbols_size, KM_SLEEP)) == NULL) 
+                       return (ENOMEM);
+                       
+               rval = 0;
+
+               /* NOTE! We can no longer exit this method via return */
+               if (copyin(arg, module_symbols, module_symbols_size) != 0) {
+                       cmn_err(CE_WARN, "failed copyin of dtrace_module_symbols_t, symbol count %llu", module_symbols->dtmodsyms_count);
+                       rval = EFAULT;
+                       goto module_symbols_cleanup;
+               }
+                       
+               /*
+                * Check that the count didn't change between the first copyin and the second.
+                */
+               if (module_symbols->dtmodsyms_count != dtmodsyms_count) {
+                       rval = EINVAL;
+                       goto module_symbols_cleanup;
+               }
+                       
+               /*
+                * Find the modctl to add symbols to.
+                */
+               lck_mtx_lock(&dtrace_provider_lock);
+               lck_mtx_lock(&mod_lock);
+               
+               struct modctl* ctl = dtrace_modctl_list;
+               while (ctl) {
+                       /* Update the private probes bit */
+                       if (dtrace_provide_private_probes)
+                               ctl->mod_flags |= MODCTL_FBT_PROVIDE_PRIVATE_PROBES;
+
+                       ASSERT(!MOD_HAS_USERSPACE_SYMBOLS(ctl));
+                       if (MOD_HAS_UUID(ctl) && !MOD_SYMBOLS_DONE(ctl)) {
+                               if (memcmp(module_symbols->dtmodsyms_uuid, ctl->mod_uuid, sizeof(UUID)) == 0) {
+                                       /* BINGO! */
+                                       ctl->mod_user_symbols = module_symbols;
+                                       break;
+                               }
+                       }
+                       ctl = ctl->mod_next;
+               }
+
+               if (ctl) {
+                       dtrace_provider_t *prv;
+
+                       /*
+                        * We're going to call each providers per-module provide operation
+                        * specifying only this module.
+                        */
+                       for (prv = dtrace_provider; prv != NULL; prv = prv->dtpv_next)
+                               prv->dtpv_pops.dtps_provide_module(prv->dtpv_arg, ctl); 
+                                               
+                       /*
+                        * We gave every provider a chance to provide with the user syms, go ahead and clear them
+                        */
+                       ctl->mod_user_symbols = NULL; /* MUST reset this to clear HAS_USERSPACE_SYMBOLS */
+               }
+               
+               lck_mtx_unlock(&mod_lock);
+               lck_mtx_unlock(&dtrace_provider_lock);
+
+       module_symbols_cleanup:
+               /*
+                * If we had to allocate struct memory, free it.
+                */
+               if (module_symbols != NULL) {
+                       kmem_free(module_symbols, module_symbols_size);
+               }
+               
+               return rval;
+       }
+
+       case DTRACEIOC_PROCWAITFOR: {
+               dtrace_procdesc_t pdesc = {
+                       .p_comm = {0},
+                       .p_pid  = -1
+               };
+
+               if ((rval = copyin(arg, &pdesc, sizeof(pdesc))) != 0)
+                       goto proc_waitfor_error;
+
+               if ((rval = dtrace_proc_waitfor(&pdesc)) != 0)
+                       goto proc_waitfor_error;
+
+               if ((rval = copyout(&pdesc, arg, sizeof(pdesc))) != 0)
+                       goto proc_waitfor_error;
+
+               return 0;
+
+       proc_waitfor_error:
+               /* The process was suspended, revert this since the client will not do it. */
+               if (pdesc.p_pid != -1) {
+                       proc_t *proc = proc_find(pdesc.p_pid);
+                       if (proc != PROC_NULL) {
+                               task_pidresume(proc->task);
+                               proc_rele(proc);
+                       }
+               }
+
+               return rval;
+       }
+
        default:
                break;
        }
@@ -16068,11 +17123,9 @@ dtrace_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv)
        return (ENOTTY);
 }
 
-#if defined(__APPLE__)
-#undef copyin
-#undef copyout
-#endif /* __APPLE__ */
-
+/*
+ * APPLE NOTE:  dtrace_detach not implemented
+ */
 #if !defined(__APPLE__)
 /*ARGSUSED*/
 static int
@@ -16098,15 +17151,15 @@ dtrace_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
        ASSERT(dtrace_opens == 0);
 
        if (dtrace_helpers > 0) {
-               lck_mtx_unlock(&dtrace_provider_lock);
                lck_mtx_unlock(&dtrace_lock);
+               lck_mtx_unlock(&dtrace_provider_lock);
                lck_mtx_unlock(&cpu_lock);
                return (DDI_FAILURE);
        }
 
        if (dtrace_unregister((dtrace_provider_id_t)dtrace_provider) != 0) {
-               lck_mtx_unlock(&dtrace_provider_lock);
                lck_mtx_unlock(&dtrace_lock);
+               lck_mtx_unlock(&dtrace_provider_lock);
                lck_mtx_unlock(&cpu_lock);
                return (DDI_FAILURE);
        }
@@ -16198,90 +17251,7 @@ dtrace_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
 
        return (DDI_SUCCESS);
 }
-
-/*ARGSUSED*/
-static int
-dtrace_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
-{
-       int error;
-
-       switch (infocmd) {
-       case DDI_INFO_DEVT2DEVINFO:
-               *result = (void *)dtrace_devi;
-               error = DDI_SUCCESS;
-               break;
-       case DDI_INFO_DEVT2INSTANCE:
-               *result = (void *)0;
-               error = DDI_SUCCESS;
-               break;
-       default:
-               error = DDI_FAILURE;
-       }
-       return (error);
-}
-
-static struct cb_ops dtrace_cb_ops = {
-       dtrace_open,            /* open */
-       dtrace_close,           /* close */
-       nulldev,                /* strategy */
-       nulldev,                /* print */
-       nodev,                  /* dump */
-       nodev,                  /* read */
-       nodev,                  /* write */
-       dtrace_ioctl,           /* ioctl */
-       nodev,                  /* devmap */
-       nodev,                  /* mmap */
-       nodev,                  /* segmap */
-       nochpoll,               /* poll */
-       ddi_prop_op,            /* cb_prop_op */
-       0,                      /* streamtab  */
-       D_NEW | D_MP            /* Driver compatibility flag */
-};
-
-static struct dev_ops dtrace_ops = {
-       DEVO_REV,               /* devo_rev */
-       0,                      /* refcnt */
-       dtrace_info,            /* get_dev_info */
-       nulldev,                /* identify */
-       nulldev,                /* probe */
-       dtrace_attach,          /* attach */
-       dtrace_detach,          /* detach */
-       nodev,                  /* reset */
-       &dtrace_cb_ops,         /* driver operations */
-       NULL,                   /* bus operations */
-       nodev                   /* dev power */
-};
-
-static struct modldrv modldrv = {
-       &mod_driverops,         /* module type (this is a pseudo driver) */
-       "Dynamic Tracing",      /* name of module */
-       &dtrace_ops,            /* driver ops */
-};
-
-static struct modlinkage modlinkage = {
-       MODREV_1,
-       (void *)&modldrv,
-       NULL
-};
-
-int
-_init(void)
-{
-       return (mod_install(&modlinkage));
-}
-
-int
-_info(struct modinfo *modinfop)
-{
-       return (mod_info(&modlinkage, modinfop));
-}
-
-int
-_fini(void)
-{
-       return (mod_remove(&modlinkage));
-}
-#else
+#endif  /* __APPLE__ */
 
 d_open_t _dtrace_open, helper_open;
 d_close_t _dtrace_close, helper_close;
@@ -16322,16 +17292,22 @@ _dtrace_ioctl(dev_t dev, u_long cmd, caddr_t data, int fflag, struct proc *p)
 {
 #pragma unused(p)
        int err, rv = 0;
+    user_addr_t uaddrp;
+
+    if (proc_is64bit(p))
+               uaddrp = *(user_addr_t *)data;
+       else
+               uaddrp = (user_addr_t) *(uint32_t *)data;
 
-       err = dtrace_ioctl(dev, (int)cmd, *(intptr_t *)data, fflag, CRED(), &rv);
+       err = dtrace_ioctl(dev, cmd, uaddrp, fflag, CRED(), &rv);
        
-       /* XXX Darwin's BSD ioctls only return -1 or zero. Overload errno to mimic Solaris. 20 bits suffice. */
+       /* Darwin's BSD ioctls only return -1 or zero. Overload errno to mimic Solaris. 20 bits suffice. */
        if (err != 0) {
                ASSERT( (err & 0xfffff000) == 0 );
-               return (err & 0xfff); /* ioctl returns -1 and errno set to an error code < 4096 */
+               return (err & 0xfff); /* ioctl will return -1 and will set errno to an error code < 4096 */
        } else if (rv != 0) {
                ASSERT( (rv & 0xfff00000) == 0 );
-               return (((rv & 0xfffff) << 12)); /* ioctl returns -1 and errno set to a return value >= 4096 */
+               return (((rv & 0xfffff) << 12)); /* ioctl will return -1 and will set errno to a value >= 4096 */
        } else 
                return 0;
 }
@@ -16342,14 +17318,14 @@ helper_ioctl(dev_t dev, u_long cmd, caddr_t data, int fflag, struct proc *p)
 #pragma unused(dev,fflag,p)
        int err, rv = 0;
        
-       err = dtrace_ioctl_helper((int)cmd, data, &rv);
-       /* XXX Darwin's BSD ioctls only return -1 or zero. Overload errno to mimic Solaris. 20 bits suffice. */
+       err = dtrace_ioctl_helper(cmd, data, &rv);
+       /* Darwin's BSD ioctls only return -1 or zero. Overload errno to mimic Solaris. 20 bits suffice. */
        if (err != 0) {
                ASSERT( (err & 0xfffff000) == 0 );
-               return (err & 0xfff); /* ioctl returns -1 and errno set to an error code < 4096 */
+               return (err & 0xfff); /* ioctl will return -1 and will set errno to an error code < 4096 */
        } else if (rv != 0) {
                ASSERT( (rv & 0xfff00000) == 0 );
-               return (((rv & 0xfffff) << 20)); /* ioctl returns -1 and errno set to a return value >= 4096 */
+               return (((rv & 0xfffff) << 12)); /* ioctl will return -1 and will set errno to a value >= 4096 */
        } else 
                return 0;
 }
@@ -16429,7 +17405,7 @@ dtrace_clone_func(dev_t dev, int action)
                else {
                        /*
                         * Propose a minor number, namely the next number that vmem_alloc() will return.
-                        * Immediately put it back in play by calling vmem_free().
+                        * Immediately put it back in play by calling vmem_free(). FIXME.
                         */
                        int ret = (int)(uintptr_t)vmem_alloc(dtrace_minor, 1, VM_BESTFIT | VM_SLEEP);
 
@@ -16474,7 +17450,37 @@ void
 dtrace_init( void )
 {
        if (0 == gDTraceInited) {
-               int i, ncpu = NCPU;
+               int i, ncpu;
+               size_t size = sizeof(dtrace_buffer_memory_maxsize);
+
+               /*
+                * DTrace allocates buffers based on the maximum number
+                * of enabled cpus. This call avoids any race when finding
+                * that count.
+                */
+               ASSERT(dtrace_max_cpus == 0);
+               ncpu = dtrace_max_cpus = ml_get_max_cpus();
+
+               /*
+                * Retrieve the size of the physical memory in order to define
+                * the state buffer memory maximal size.  If we cannot retrieve
+                * this value, we'll consider that we have 1Gb of memory per CPU, that's
+                * still better than raising a kernel panic.
+                */
+               if (0 != kernel_sysctlbyname("hw.memsize", &dtrace_buffer_memory_maxsize,
+                                            &size, NULL, 0))
+               {
+                       dtrace_buffer_memory_maxsize = ncpu * 1024 * 1024 * 1024;
+                       printf("dtrace_init: failed to retrieve the hw.memsize, defaulted to %lld bytes\n",
+                              dtrace_buffer_memory_maxsize);
+               }
+
+               /*
+                * Finally, divide by three to prevent DTrace from eating too
+                * much memory.
+                */
+               dtrace_buffer_memory_maxsize /= 3;
+               ASSERT(dtrace_buffer_memory_maxsize > 0);
 
                gMajDevNo = cdevsw_add(DTRACE_MAJOR, &dtrace_cdevsw);
 
@@ -16492,12 +17498,10 @@ dtrace_init( void )
                }
 
 #if defined(DTRACE_MEMORY_ZONES)
-
                /*
                 * Initialize the dtrace kalloc-emulation zones.
                 */
                dtrace_alloc_init();
-
 #endif /* DTRACE_MEMORY_ZONES */
 
                /*
@@ -16521,7 +17525,8 @@ dtrace_init( void )
                lck_mtx_init(&dtrace_lock, dtrace_lck_grp, dtrace_lck_attr);
                lck_mtx_init(&dtrace_provider_lock, dtrace_lck_grp, dtrace_lck_attr);
                lck_mtx_init(&dtrace_meta_lock, dtrace_lck_grp, dtrace_lck_attr);
-#ifdef DEBUG
+               lck_mtx_init(&dtrace_procwaitfor_lock, dtrace_lck_grp, dtrace_lck_attr);
+#if DEBUG
                lck_mtx_init(&dtrace_errlock, dtrace_lck_grp, dtrace_lck_attr);
 #endif
                lck_rw_init(&dtrace_dof_mode_lock, dtrace_lck_grp, dtrace_lck_attr);
@@ -16534,32 +17539,44 @@ dtrace_init( void )
                 * the structure is sized to avoid false sharing.
                 */
                lck_mtx_init(&cpu_lock, dtrace_lck_grp, dtrace_lck_attr);
+               lck_mtx_init(&cyc_lock, dtrace_lck_grp, dtrace_lck_attr);
                lck_mtx_init(&mod_lock, dtrace_lck_grp, dtrace_lck_attr);
 
+               /*
+                * Initialize the CPU offline/online hooks.
+                */
+               dtrace_install_cpu_hooks();
+
+               dtrace_modctl_list = NULL;
+
                cpu_core = (cpu_core_t *)kmem_zalloc( ncpu * sizeof(cpu_core_t), KM_SLEEP );
                for (i = 0; i < ncpu; ++i) {
                        lck_mtx_init(&cpu_core[i].cpuc_pid_lock, dtrace_lck_grp, dtrace_lck_attr);
                }
 
-               cpu_list = (cpu_t *)kmem_zalloc( ncpu * sizeof(cpu_t), KM_SLEEP );
+               cpu_list = (dtrace_cpu_t *)kmem_zalloc( ncpu * sizeof(dtrace_cpu_t), KM_SLEEP );
                for (i = 0; i < ncpu; ++i) {
                        cpu_list[i].cpu_id = (processorid_t)i;
                        cpu_list[i].cpu_next = &(cpu_list[(i+1) % ncpu]);
+                       LIST_INIT(&cpu_list[i].cpu_cyc_list);
                        lck_rw_init(&cpu_list[i].cpu_ft_lock, dtrace_lck_grp, dtrace_lck_attr);
                }
 
                lck_mtx_lock(&cpu_lock);
                for (i = 0; i < ncpu; ++i) 
+                       /* FIXME: track CPU configuration a la CHUD Processor Pref Pane. */
                        dtrace_cpu_setup_initial( (processorid_t)i ); /* In lieu of register_cpu_setup_func() callback */
                lck_mtx_unlock(&cpu_lock);
 
                (void)dtrace_abs_to_nano(0LL); /* Force once only call to clock_timebase_info (which can take a lock) */
 
+               dtrace_isa_init();
+               
                /*
                 * See dtrace_impl.h for a description of dof modes.
                 * The default is lazy dof.
                 *
-                * XXX Warn if state is LAZY_OFF? It won't break anything, but
+                * FIXME: Warn if state is LAZY_OFF? It won't break anything, but
                 * makes no sense...
                 */
                if (!PE_parse_boot_argn("dtrace_dof_mode", &dtrace_dof_mode, sizeof (dtrace_dof_mode))) {
@@ -16588,6 +17605,14 @@ dtrace_init( void )
                                break;
                }
 
+               /*
+                * See dtrace_impl.h for a description of kernel symbol modes.
+                * The default is to wait for symbols from userspace (lazy symbols).
+                */
+               if (!PE_parse_boot_argn("dtrace_kernel_symbol_mode", &dtrace_kernel_symbol_mode, sizeof (dtrace_kernel_symbol_mode))) {
+                       dtrace_kernel_symbol_mode = DTRACE_KERNEL_SYMBOLS_FROM_USERSPACE;
+               }
+                               
                gDTraceInited = 1;
 
        } else
@@ -16597,7 +17622,29 @@ dtrace_init( void )
 void
 dtrace_postinit(void)
 {
-               dtrace_attach( (dev_info_t *)makedev(gMajDevNo, 0), 0 );
+       /*
+        * Called from bsd_init after all provider's *_init() routines have been
+        * run. That way, anonymous DOF enabled under dtrace_attach() is safe
+        * to go.
+        */
+       dtrace_attach( (dev_info_t *)(uintptr_t)makedev(gMajDevNo, 0), 0 ); /* Punning a dev_t to a dev_info_t* */
+       
+       /*
+        * Add the mach_kernel to the module list for lazy processing
+        */
+       struct kmod_info fake_kernel_kmod;
+       memset(&fake_kernel_kmod, 0, sizeof(fake_kernel_kmod));
+       
+       strlcpy(fake_kernel_kmod.name, "mach_kernel", sizeof(fake_kernel_kmod.name));
+       fake_kernel_kmod.id = 1;
+       fake_kernel_kmod.address = g_kernel_kmod_info.address;
+       fake_kernel_kmod.size = g_kernel_kmod_info.size;
+
+       if (dtrace_module_loaded(&fake_kernel_kmod, 0) != 0) {
+               printf("dtrace_postinit: Could not register mach_kernel modctl\n");
+       }
+       
+       (void)OSKextRegisterKextsWithDTrace();
 }
 #undef DTRACE_MAJOR
 
@@ -16616,4 +17663,3 @@ unregister_cpu_setup_func(cpu_setup_func_t *ignore1, void *ignore2)
 {
 #pragma unused(ignore1,ignore2)
 }
-#endif /* __APPLE__ */