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xnu-4903.221.2.tar.gz
[apple/xnu.git] / bsd / dev / dtrace / sdt.c
index 946c6a4c617d21f2de878e741efd8d1fd71a311e..1abf6f14c69193409daa7c9ec1fbd68ae472dbcc 100644 (file)
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-/* #pragma ident       "@(#)sdt.c      1.6     06/03/24 SMI" */
+/* #pragma ident       "@(#)sdt.c      1.9     08/07/01 SMI" */
 
 #ifdef KERNEL
 #ifndef _KERNEL
 #include <sys/fcntl.h>
 #include <miscfs/devfs/devfs.h>
 
+#if CONFIG_EMBEDDED
+#include <arm/caches_internal.h>
+#endif
+
 #include <sys/dtrace.h>
 #include <sys/dtrace_impl.h>
 
 #include <sys/dtrace_glue.h>
 
 #include <sys/sdt_impl.h>
+extern int dtrace_kernel_symbol_mode;
 
+/* #include <machine/trap.h */
 struct savearea_t; /* Used anonymously */
-typedef kern_return_t (*perfCallback)(int, struct savearea_t *, int, int);
-
-#if defined (__ppc__) || defined (__ppc64__)
-extern perfCallback tempDTraceTrapHook, tempDTraceIntHook;
-extern kern_return_t fbt_perfCallback(int, struct savearea_t *, int, int);
-extern kern_return_t fbt_perfIntCallback(int, struct savearea_t *, int, int);
 
-#define        SDT_PATCHVAL    0x7c810808
-#define SDT_AFRAMES     6
-#elif defined(__i386__) || defined(__x86_64__)
+#if defined(__arm__)
+typedef kern_return_t (*perfCallback)(int, struct savearea_t *, __unused int, __unused int);
 extern perfCallback tempDTraceTrapHook;
-extern kern_return_t fbt_perfCallback(int, struct savearea_t *, int, int);
-
+extern kern_return_t fbt_perfCallback(int, struct savearea_t *, __unused int, __unused int);
+#define        SDT_PATCHVAL    0xdefc
+#define        SDT_AFRAMES             7
+#elif defined(__arm64__)
+typedef kern_return_t (*perfCallback)(int, struct savearea_t *, __unused int, __unused int);
+extern perfCallback tempDTraceTrapHook;
+extern kern_return_t fbt_perfCallback(int, struct savearea_t *, __unused int, __unused int);
+#define        SDT_PATCHVAL    0xe7eeee7e
+#define        SDT_AFRAMES             7
+#elif defined(__x86_64__)
+typedef kern_return_t (*perfCallback)(int, struct savearea_t *, uintptr_t *, int);
+extern perfCallback tempDTraceTrapHook;
+extern kern_return_t fbt_perfCallback(int, struct savearea_t *, uintptr_t *, int);
 #define        SDT_PATCHVAL    0xf0
 #define        SDT_AFRAMES             6
 #else
@@ -69,7 +79,8 @@ extern kern_return_t fbt_perfCallback(int, struct savearea_t *, int, int);
 
 #define        SDT_PROBETAB_SIZE       0x1000          /* 4k entries -- 16K total */
 
-static dev_info_t              *sdt_devi;
+#define DTRACE_PROBE_PREFIX "_dtrace_probe$"
+
 static int                     sdt_verbose = 0;
 sdt_probe_t            **sdt_probetab;
 int                    sdt_probetab_size;
@@ -80,7 +91,7 @@ static void
 __sdt_provide_module(void *arg, struct modctl *ctl)
 {
 #pragma unused(arg)
-       struct module *mp = (struct module *)ctl->address;
+       struct module *mp = (struct module *)ctl->mod_address;
        char *modname = ctl->mod_modname;
        sdt_probedesc_t *sdpd;
        sdt_probe_t *sdp, *old;
@@ -96,16 +107,17 @@ __sdt_provide_module(void *arg, struct modctl *ctl)
                        return;
        }
 
-       if (mp->sdt_nprobes != 0 || (sdpd = mp->sdt_probes) == NULL)
+       if (!mp || mp->sdt_nprobes != 0 || (sdpd = mp->sdt_probes) == NULL)
                return;
 
        for (sdpd = mp->sdt_probes; sdpd != NULL; sdpd = sdpd->sdpd_next) {
-               char *name = sdpd->sdpd_name, *func, *nname;
+           const char *name = sdpd->sdpd_name, *func;
+           char *nname;
                int i, j;
                dtrace_id_t id;
 
                for (prov = sdt_providers; prov->sdtp_prefix != NULL; prov++) {
-                       char *prefpart, *prefix = prov->sdtp_prefix;
+                       const char *prefpart, *prefix = prov->sdtp_prefix;
 
                        if ((prefpart = strstr(name, prefix))) {
                                name = prefpart + strlen(prefix);
@@ -156,6 +168,10 @@ __sdt_provide_module(void *arg, struct modctl *ctl)
                        mp->sdt_nprobes++;
                }
 
+#if 0          
+               printf ("__sdt_provide_module:  sdpd=0x%p  sdp=0x%p  name=%s, id=%d\n", sdpd, sdp, nname, sdp->sdp_id);
+#endif         
+
                sdp->sdp_hashnext =
                    sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)];
                sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)] = sdp;
@@ -173,7 +189,11 @@ sdt_destroy(void *arg, dtrace_id_t id, void *parg)
 #pragma unused(arg,id)
        sdt_probe_t *sdp = parg, *old, *last, *hash;
        int ndx;
+
 #if !defined(__APPLE__)
+       /*
+        * APPLE NOTE:  sdt probes for kexts not yet implemented
+        */
        struct modctl *ctl = sdp->sdp_ctl;
 
        if (ctl != NULL && ctl->mod_loadcnt == sdp->sdp_loadcnt) {
@@ -213,14 +233,13 @@ sdt_destroy(void *arg, dtrace_id_t id, void *parg)
 }
 
 /*ARGSUSED*/
-static void
+static int
 sdt_enable(void *arg, dtrace_id_t id, void *parg)
 {
 #pragma unused(arg,id)
        sdt_probe_t *sdp = parg;
        struct modctl *ctl = sdp->sdp_ctl;
 
-#if !defined(__APPLE__)
        ctl->mod_nenabled++;
 
        /*
@@ -249,20 +268,7 @@ sdt_enable(void *arg, dtrace_id_t id, void *parg)
                }
                goto err;
        }
-#endif /* __APPLE__ */
 
-#if defined (__ppc__) || defined (__ppc64__)
-       dtrace_casptr(&tempDTraceIntHook, NULL, fbt_perfIntCallback);
-       if (tempDTraceIntHook != (perfCallback)fbt_perfIntCallback) {
-               if (sdt_verbose) {
-                       cmn_err(CE_NOTE, "sdt_enable is failing for probe %s "
-                           "in module %s: tempDTraceIntHook already occupied.",
-                           sdp->sdp_name, ctl->mod_modname);
-               }
-               return;
-       }
-#endif
-       
        dtrace_casptr(&tempDTraceTrapHook, NULL, fbt_perfCallback);
        if (tempDTraceTrapHook != (perfCallback)fbt_perfCallback) {
                if (sdt_verbose) {
@@ -270,16 +276,25 @@ sdt_enable(void *arg, dtrace_id_t id, void *parg)
                            "in module %s: tempDTraceTrapHook already occupied.",
                            sdp->sdp_name, ctl->mod_modname);
                }
-               return;
+               return (0);
        }
 
        while (sdp != NULL) {
                (void)ml_nofault_copy( (vm_offset_t)&sdp->sdp_patchval, (vm_offset_t)sdp->sdp_patchpoint, 
-                                                               sizeof(sdp->sdp_patchval));
+                                      (vm_size_t)sizeof(sdp->sdp_patchval));
+
+               /*
+                * Make the patched instruction visible via a data + instruction
+                * cache fush on platforms that need it
+                */
+               flush_dcache((vm_offset_t)sdp->sdp_patchpoint,(vm_size_t)sizeof(sdp->sdp_patchval), 0);
+               invalidate_icache((vm_offset_t)sdp->sdp_patchpoint,(vm_size_t)sizeof(sdp->sdp_patchval), 0);
+
                sdp = sdp->sdp_next;
        }
+
 err:
-       ;
+       return (0);
 }
 
 /*ARGSUSED*/
@@ -288,18 +303,22 @@ sdt_disable(void *arg, dtrace_id_t id, void *parg)
 {
 #pragma unused(arg,id)
        sdt_probe_t *sdp = parg;
-#if !defined(__APPLE__)
        struct modctl *ctl = sdp->sdp_ctl;
 
        ctl->mod_nenabled--;
 
        if (!ctl->mod_loaded || ctl->mod_loadcnt != sdp->sdp_loadcnt)
                goto err;
-#endif /* __APPLE__ */
 
        while (sdp != NULL) {
                (void)ml_nofault_copy( (vm_offset_t)&sdp->sdp_savedval, (vm_offset_t)sdp->sdp_patchpoint, 
-                                                               sizeof(sdp->sdp_savedval));
+                                      (vm_size_t)sizeof(sdp->sdp_savedval));
+               /*
+                * Make the patched instruction visible via a data + instruction
+                * cache flush on platforms that need it
+                */
+               flush_dcache((vm_offset_t)sdp->sdp_patchpoint,(vm_size_t)sizeof(sdp->sdp_savedval), 0);
+               invalidate_icache((vm_offset_t)sdp->sdp_patchpoint,(vm_size_t)sizeof(sdp->sdp_savedval), 0);
                sdp = sdp->sdp_next;
        }
 
@@ -308,23 +327,22 @@ err:
 }
 
 static dtrace_pops_t sdt_pops = {
-       NULL,
-       sdt_provide_module,
-       sdt_enable,
-       sdt_disable,
-       NULL,
-       NULL,
-       sdt_getargdesc,
-       NULL,
-       NULL,
-       sdt_destroy
+       .dtps_provide =         NULL,
+       .dtps_provide_module =  sdt_provide_module,
+       .dtps_enable =          sdt_enable,
+       .dtps_disable =         sdt_disable,
+       .dtps_suspend =         NULL,
+       .dtps_resume =          NULL,
+       .dtps_getargdesc =      sdt_getargdesc,
+       .dtps_getargval =       sdt_getarg,
+       .dtps_usermode =        NULL,
+       .dtps_destroy =         sdt_destroy,
 };
 
 /*ARGSUSED*/
 static int
-sdt_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
+sdt_attach(dev_info_t *devi)
 {
-#pragma unused(cmd)
        sdt_provider_t *prov;
 
        if (ddi_create_minor_node(devi, "sdt", S_IFCHR,
@@ -334,9 +352,6 @@ sdt_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
                return (DDI_FAILURE);
        }
 
-       ddi_report_dev(devi);
-       sdt_devi = devi;
-
        if (sdt_probetab_size == 0)
                sdt_probetab_size = SDT_PROBETAB_SIZE;
 
@@ -357,6 +372,9 @@ sdt_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
        return (DDI_SUCCESS);
 }
 
+/*
+ * APPLE NOTE:  sdt_detach not implemented
+ */
 #if !defined(__APPLE__)
 /*ARGSUSED*/
 static int
@@ -389,100 +407,8 @@ sdt_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
 
        return (DDI_SUCCESS);
 }
+#endif /* __APPLE__ */
 
-/*ARGSUSED*/
-static int
-sdt_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
-{
-       int error;
-
-       switch (infocmd) {
-       case DDI_INFO_DEVT2DEVINFO:
-               *result = (void *)sdt_devi;
-               error = DDI_SUCCESS;
-               break;
-       case DDI_INFO_DEVT2INSTANCE:
-               *result = (void *)0;
-               error = DDI_SUCCESS;
-               break;
-       default:
-               error = DDI_FAILURE;
-       }
-       return (error);
-}
-
-/*ARGSUSED*/
-static int
-sdt_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
-{
-       return (0);
-}
-
-static struct cb_ops sdt_cb_ops = {
-       sdt_open,               /* open */
-       nodev,                  /* close */
-       nulldev,                /* strategy */
-       nulldev,                /* print */
-       nodev,                  /* dump */
-       nodev,                  /* read */
-       nodev,                  /* write */
-       nodev,                  /* 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 sdt_ops = {
-       DEVO_REV,               /* devo_rev, */
-       0,                      /* refcnt  */
-       sdt_info,               /* get_dev_info */
-       nulldev,                /* identify */
-       nulldev,                /* probe */
-       sdt_attach,             /* attach */
-       sdt_detach,             /* detach */
-       nodev,                  /* reset */
-       &sdt_cb_ops,            /* driver operations */
-       NULL,                   /* bus operations */
-       nodev                   /* dev power */
-};
-
-/*
- * Module linkage information for the kernel.
- */
-static struct modldrv modldrv = {
-       &mod_driverops,         /* module type (this is a pseudo driver) */
-       "Statically Defined Tracing",   /* name of module */
-       &sdt_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
 d_open_t _sdt_open;
 
 int _sdt_open(dev_t dev, int flags, int devtype, struct proc *p)
@@ -515,160 +441,196 @@ static struct cdevsw sdt_cdevsw =
        0                                       /* type */
 };
 
-static int gSDTInited = 0;
 static struct modctl g_sdt_kernctl;
 static struct module g_sdt_mach_module;
 
-#include <mach-o/loader.h>
 #include <mach-o/nlist.h>
+#include <libkern/kernel_mach_header.h>
 
-extern struct mach_header _mh_execute_header; /* the kernel's mach header */
-
-void sdt_init( void )
+void sdt_early_init( void )
 {
-       if (0 == gSDTInited)
-       {
-               int majdevno = cdevsw_add(SDT_MAJOR, &sdt_cdevsw);
+       if (dtrace_sdt_probes_restricted()) {
+               return;
+       }
+       if (MH_MAGIC_KERNEL != _mh_execute_header.magic) {
+               g_sdt_kernctl.mod_address = (vm_address_t)NULL;
+               g_sdt_kernctl.mod_size = 0;
+       } else {
+               kernel_mach_header_t        *mh;
+               struct load_command         *cmd;
+               kernel_segment_command_t    *orig_ts = NULL, *orig_le = NULL;
+               struct symtab_command       *orig_st = NULL;
+               kernel_nlist_t              *sym = NULL;
+               char                        *strings;
+               unsigned int                i;
                
-               if (majdevno < 0) {
-                       printf("sdt_init: failed to allocate a major number!\n");
-                       gSDTInited = 0;
-                       return;
-               }
-
-               if (MH_MAGIC != _mh_execute_header.magic) {
-               g_sdt_kernctl.address = (vm_address_t)NULL;
-               g_sdt_kernctl.size = 0;
-               } else {
-               struct mach_header          *mh;
-               struct load_command         *cmd;
-               struct segment_command      *orig_ts = NULL, *orig_le = NULL;
-               struct symtab_command       *orig_st = NULL;
-               struct nlist                *sym = NULL;
-               char                        *strings;
-               unsigned int i;
-
                g_sdt_mach_module.sdt_nprobes = 0;
                g_sdt_mach_module.sdt_probes = NULL;
-
-               g_sdt_kernctl.address = (vm_address_t)&g_sdt_mach_module;
-               g_sdt_kernctl.size = 0;
+               
+               g_sdt_kernctl.mod_address = (vm_address_t)&g_sdt_mach_module;
+               g_sdt_kernctl.mod_size = 0;
                strncpy((char *)&(g_sdt_kernctl.mod_modname), "mach_kernel", KMOD_MAX_NAME);
-
+               
+               g_sdt_kernctl.mod_next = NULL;
+               g_sdt_kernctl.mod_stale = NULL;
+               g_sdt_kernctl.mod_id = 0;
+               g_sdt_kernctl.mod_loadcnt = 1;
+               g_sdt_kernctl.mod_loaded = 1;
+               g_sdt_kernctl.mod_flags = 0;
+               g_sdt_kernctl.mod_nenabled = 0;
+               
                mh = &_mh_execute_header;
-               cmd = (struct load_command *) &mh[1];
-               for (i = 0; i < mh->ncmds; i++) {
-                       if (cmd->cmd == LC_SEGMENT) {
-                       struct segment_command *orig_sg = (struct segment_command *) cmd;
-
-                       if (strcmp(SEG_TEXT, orig_sg->segname) == 0)
-                               orig_ts = orig_sg;
-                       else if (strcmp(SEG_LINKEDIT, orig_sg->segname) == 0)
-                               orig_le = orig_sg;
-                       else if (strcmp("", orig_sg->segname) == 0)
-                               orig_ts = orig_sg; /* kexts have a single unnamed segment */
-                       }
-                       else if (cmd->cmd == LC_SYMTAB)
-                       orig_st = (struct symtab_command *) cmd;
-       
-                       cmd = (struct load_command *) ((caddr_t) cmd + cmd->cmdsize);
-               }
-       
-               if ((orig_ts == NULL) || (orig_st == NULL) || (orig_le == NULL))
-                       return;
-
-               sym = (struct nlist *)orig_le->vmaddr;
-               strings = ((char *)sym) + orig_st->nsyms * sizeof(struct nlist);
-
-               for (i = 0; i < orig_st->nsyms; i++) {
-                       uint8_t n_type = sym[i].n_type & (N_TYPE | N_EXT);
-                       char *name = strings + sym[i].n_un.n_strx;
-                               char *prev_name;
-                               unsigned long best;
-                               unsigned int j;
-
-                       /* Check that the symbol is a global and that it has a name. */
-                       if (((N_SECT | N_EXT) != n_type && (N_ABS | N_EXT) != n_type))
-                       continue;
-
-                       if (0 == sym[i].n_un.n_strx) /* iff a null, "", name. */
-                       continue;
-
-                       /* Lop off omnipresent leading underscore. */
-                       if (*name == '_')
-                       name += 1;
-
-                               if (strstr(name, "_dtrace_probe$")) {
-                                       sdt_probedesc_t *sdpd = kmem_alloc(sizeof(sdt_probedesc_t), KM_SLEEP);
-                                       int len = strlen(name) + 1;
-
-                                       sdpd->sdpd_name = kmem_alloc(len, KM_SLEEP);
-                                       strncpy(sdpd->sdpd_name, name, len); /* NUL termination is ensured. */
-
-                                       prev_name = "<unknown>";
-                                       best = 0;
-                                       for (j = 0; j < orig_st->nsyms; j++) {
-                                               uint8_t n_type = sym[j].n_type & (N_TYPE | N_EXT);
-                                               char *name = strings + sym[j].n_un.n_strx;
-
-                                               if (((N_SECT | N_EXT) != n_type && (N_ABS | N_EXT) != n_type))
-                                                       continue;
-
-                                               if (0 == sym[j].n_un.n_strx) /* iff a null, "", name. */
-                                                       continue;
-
-                                               if (*name == '_')
-                                                       name += 1;
-                                               if (strstr(name, "_dtrace_probe$"))
-                                                       continue;
-
-                                               if (*(unsigned long *)sym[i].n_value <= (unsigned long)sym[j].n_value)
-                                                       continue;
-
-                                               if ((unsigned long)sym[j].n_value > best) {
-                                                       best = (unsigned long)sym[j].n_value;
-                                                       prev_name = name;
-                                               }
+               cmd = (struct load_command*) &mh[1];
+               for (i = 0; i < mh->ncmds; i++) {
+                       if (cmd->cmd == LC_SEGMENT_KERNEL) {
+                               kernel_segment_command_t *orig_sg = (kernel_segment_command_t *) cmd;
+                               
+                               if (LIT_STRNEQL(orig_sg->segname, SEG_TEXT))
+                                       orig_ts = orig_sg;
+                               else if (LIT_STRNEQL(orig_sg->segname, SEG_LINKEDIT))
+                                       orig_le = orig_sg;
+                               else if (LIT_STRNEQL(orig_sg->segname, ""))
+                                       orig_ts = orig_sg; /* kexts have a single unnamed segment */
+                       }
+                       else if (cmd->cmd == LC_SYMTAB)
+                               orig_st = (struct symtab_command *) cmd;
+                       
+                       cmd = (struct load_command *) ((uintptr_t) cmd + cmd->cmdsize);
+               }
+               
+               if ((orig_ts == NULL) || (orig_st == NULL) || (orig_le == NULL))
+                       return;
+               
+               sym = (kernel_nlist_t *)(orig_le->vmaddr + orig_st->symoff - orig_le->fileoff);
+               strings = (char *)(orig_le->vmaddr + orig_st->stroff - orig_le->fileoff);
+               
+               for (i = 0; i < orig_st->nsyms; i++) {
+                       uint8_t n_type = sym[i].n_type & (N_TYPE | N_EXT);
+                       char *name = strings + sym[i].n_un.n_strx;
+                       const char *prev_name;
+                       unsigned long best;
+                       unsigned int j;
+                       
+                       /* Check that the symbol is a global and that it has a name. */
+                       if (((N_SECT | N_EXT) != n_type && (N_ABS | N_EXT) != n_type))
+                               continue;
+                       
+                       if (0 == sym[i].n_un.n_strx) /* iff a null, "", name. */
+                               continue;
+                       
+                       /* Lop off omnipresent leading underscore. */
+                       if (*name == '_')
+                               name += 1;
+                       
+                       if (strncmp(name, DTRACE_PROBE_PREFIX, sizeof(DTRACE_PROBE_PREFIX) - 1) == 0) {
+                               sdt_probedesc_t *sdpd = kmem_alloc(sizeof(sdt_probedesc_t), KM_SLEEP);
+                               int len = strlen(name) + 1;
+                               
+                               sdpd->sdpd_name = kmem_alloc(len, KM_SLEEP);
+                               strncpy(sdpd->sdpd_name, name, len); /* NUL termination is ensured. */
+                               
+                               prev_name = "<unknown>";
+                               best = 0;
+                               
+                               /*
+                                * Find the symbol immediately preceding the sdt probe site just discovered,
+                                * that symbol names the function containing the sdt probe.
+                                */
+                               for (j = 0; j < orig_st->nsyms; j++) {
+                                       uint8_t jn_type = sym[j].n_type & N_TYPE;
+                                       char *jname = strings + sym[j].n_un.n_strx;
+
+                                       if ((N_SECT != jn_type && N_ABS != jn_type))
+                                               continue;
+
+                                       if (0 == sym[j].n_un.n_strx) /* iff a null, "", name. */
+                                               continue;
+
+                                       if (*jname == '_')
+                                               jname += 1;
+
+                                       if (*(unsigned long *)sym[i].n_value <= (unsigned long)sym[j].n_value)
+                                               continue;
+
+                                       if ((unsigned long)sym[j].n_value > best) {
+                                               best = (unsigned long)sym[j].n_value;
+                                               prev_name = jname;
                                        }
+                               }
 
-                                       sdpd->sdpd_func = kmem_alloc((len = strlen(prev_name) + 1), KM_SLEEP);
-                                       strncpy(sdpd->sdpd_func, prev_name, len); /* NUL termination is ensured. */
-
-                                       sdpd->sdpd_offset = *(unsigned long *)sym[i].n_value;
+                               sdpd->sdpd_func = kmem_alloc((len = strlen(prev_name) + 1), KM_SLEEP);
+                               strncpy(sdpd->sdpd_func, prev_name, len); /* NUL termination is ensured. */
+                               
+                               sdpd->sdpd_offset = *(unsigned long *)sym[i].n_value;
+#if defined(__arm__)
+                               /* PR8353094 - mask off thumb-bit */
+                               sdpd->sdpd_offset &= ~0x1U;
+#elif defined(__arm64__)
+                               sdpd->sdpd_offset &= ~0x1LU;
+#endif  /* __arm__ */
+
+#if 0
+                               printf("sdt_init: sdpd_offset=0x%lx, n_value=0x%lx, name=%s\n",
+                                   sdpd->sdpd_offset,  *(unsigned long *)sym[i].n_value, name);
+#endif
 
-                                       sdpd->sdpd_next = g_sdt_mach_module.sdt_probes;
-                                       g_sdt_mach_module.sdt_probes = sdpd;
-                               } else {
-                                       prev_name = name;
-                               }
+                               sdpd->sdpd_next = g_sdt_mach_module.sdt_probes;
+                               g_sdt_mach_module.sdt_probes = sdpd;
+                       } else {
+                               prev_name = name;
                        }
                }
+       }
+}
+
+void sdt_init( void )
+{
+       int majdevno = cdevsw_add(SDT_MAJOR, &sdt_cdevsw);
+               
+       if (majdevno < 0) {
+               printf("sdt_init: failed to allocate a major number!\n");
+               return;
+       }
 
-               sdt_attach( (dev_info_t *)majdevno, DDI_ATTACH );
+       if (dtrace_sdt_probes_restricted()) {
+               return;
+       }
 
-               gSDTInited = 1;
-       } else
-               panic("sdt_init: called twice!\n");
+       sdt_attach((dev_info_t*)(uintptr_t)majdevno);
 }
+
 #undef SDT_MAJOR
 
 /*ARGSUSED*/
 void
 sdt_provide_module(void *arg, struct modctl *ctl)
 {
-#pragma unused(ctl)
 #pragma unused(arg)
-    __sdt_provide_module(arg, &g_sdt_kernctl);
-
-       sdt_probedesc_t *sdpd = g_sdt_mach_module.sdt_probes;
-       while (sdpd) {
-               sdt_probedesc_t *this_sdpd = sdpd;
-               kmem_free((void *)sdpd->sdpd_name, strlen(sdpd->sdpd_name) + 1);
-               kmem_free((void *)sdpd->sdpd_func, strlen(sdpd->sdpd_func) + 1);
-               sdpd = sdpd->sdpd_next;
-               kmem_free((void *)this_sdpd, sizeof(sdt_probedesc_t));
+       ASSERT(ctl != NULL);
+       ASSERT(dtrace_kernel_symbol_mode != DTRACE_KERNEL_SYMBOLS_NEVER);
+       LCK_MTX_ASSERT(&mod_lock, LCK_MTX_ASSERT_OWNED);
+       
+       if (MOD_SDT_DONE(ctl))
+               return;
+               
+       if (MOD_IS_MACH_KERNEL(ctl)) {
+               __sdt_provide_module(arg, &g_sdt_kernctl);
+               
+               sdt_probedesc_t *sdpd = g_sdt_mach_module.sdt_probes;
+               while (sdpd) {
+                       sdt_probedesc_t *this_sdpd = sdpd;
+                       kmem_free((void *)sdpd->sdpd_name, strlen(sdpd->sdpd_name) + 1);
+                       kmem_free((void *)sdpd->sdpd_func, strlen(sdpd->sdpd_func) + 1);
+                       sdpd = sdpd->sdpd_next;
+                       kmem_free((void *)this_sdpd, sizeof(sdt_probedesc_t));
+               }
+               g_sdt_mach_module.sdt_probes = NULL;
+       } else {
+               /*
+                * APPLE NOTE:  sdt probes for kexts not yet implemented
+                */
        }
-       g_sdt_mach_module.sdt_probes = NULL;
+       
+       /* Need to mark this module as completed */
+       ctl->mod_flags |= MODCTL_SDT_PROBES_PROVIDED;
 }
-
-#endif /* __APPLE__ */