xnu-2782.30.5.tar.gz

[apple/xnu.git] / bsd / kern / kdebug.c

/*
 * Copyright (c) 2000-2013 Apple Inc. All rights reserved.
 *
 * @Apple_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */


#include <machine/spl.h>

#include <sys/errno.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc_internal.h>
#include <sys/vm.h>
#include <sys/sysctl.h>
#include <sys/kdebug.h>
#include <sys/sysproto.h>
#include <sys/bsdtask_info.h>
#include <sys/random.h>

#define HZ      100
#include <mach/clock_types.h>
#include <mach/mach_types.h>
#include <mach/mach_time.h>
#include <machine/machine_routines.h>

#if defined(__i386__) || defined(__x86_64__)
#include <i386/rtclock_protos.h>
#include <i386/mp.h>
#include <i386/machine_routines.h>
#endif

#include <kern/clock.h>

#include <kern/thread.h>
#include <kern/task.h>
#include <kern/debug.h>
#include <kern/kalloc.h>
#include <kern/cpu_data.h>
#include <kern/assert.h>
#include <kern/telemetry.h>
#include <vm/vm_kern.h>
#include <sys/lock.h>

#include <sys/malloc.h>
#include <sys/mcache.h>
#include <sys/kauth.h>

#include <sys/vnode.h>
#include <sys/vnode_internal.h>
#include <sys/fcntl.h>
#include <sys/file_internal.h>
#include <sys/ubc.h>
#include <sys/param.h>                  /* for isset() */

#include <mach/mach_host.h>             /* for host_info() */
#include <libkern/OSAtomic.h>

#include <machine/pal_routines.h>

extern boolean_t kdebug_serial;
#if KDEBUG_MOJO_TRACE
#include <sys/kdebugevents.h>
static void kdebug_serial_print(        /* forward */
                uint32_t, uint32_t, uint64_t,
                uintptr_t, uintptr_t, uintptr_t, uintptr_t, uintptr_t);
#endif

/*
 * IOP(s)
 *
 * https://coreoswiki.apple.com/wiki/pages/U6z3i0q9/Consistent_Logging_Implementers_Guide.html
 *
 * IOP(s) are auxiliary cores that want to participate in kdebug event logging.
 * They are registered dynamically. Each is assigned a cpu_id at registration.
 *
 * NOTE: IOP trace events may not use the same clock hardware as "normal"
 * cpus. There is an effort made to synchronize the IOP timebase with the
 * AP, but it should be understood that there may be discrepancies.
 *
 * Once registered, an IOP is permanent, it cannot be unloaded/unregistered.
 * The current implementation depends on this for thread safety.
 *
 * New registrations occur by allocating an kd_iop struct and assigning
 * a provisional cpu_id of list_head->cpu_id + 1. Then a CAS to claim the
 * list_head pointer resolves any races.
 *
 * You may safely walk the kd_iops list at any time, without holding locks.
 *
 * When allocating buffers, the current kd_iops head is captured. Any operations
 * that depend on the buffer state (such as flushing IOP traces on reads,
 * etc.) should use the captured list head. This will allow registrations to
 * take place while trace is in use.
 */

typedef struct kd_iop {
        kd_callback_t   callback;
        uint32_t        cpu_id;
        uint64_t        last_timestamp; /* Prevent timer rollback */
        struct kd_iop*  next;
} kd_iop_t;

static kd_iop_t* kd_iops = NULL;

/* XXX should have prototypes, but Mach does not provide one */
void task_act_iterate_wth_args(task_t, void(*)(thread_t, void *), void *);
int cpu_number(void);   /* XXX <machine/...> include path broken */
void commpage_update_kdebug_enable(void); /* XXX sign */

/* XXX should probably be static, but it's debugging code... */
int kdbg_read(user_addr_t, size_t *, vnode_t, vfs_context_t);
void kdbg_control_chud(int, void *);
int kdbg_control(int *, u_int, user_addr_t, size_t *);
int kdbg_readcpumap(user_addr_t, size_t *);
int kdbg_readcurcpumap(user_addr_t, size_t *);
int kdbg_readthrmap(user_addr_t, size_t *, vnode_t, vfs_context_t);
int kdbg_readcurthrmap(user_addr_t, size_t *);
int kdbg_getreg(kd_regtype *);
int kdbg_setreg(kd_regtype *);
int kdbg_setrtcdec(kd_regtype *);
int kdbg_setpidex(kd_regtype *);
int kdbg_setpid(kd_regtype *);
void kdbg_thrmap_init(void);
int kdbg_reinit(boolean_t);
int kdbg_bootstrap(boolean_t);

int kdbg_cpumap_init_internal(kd_iop_t* iops, uint32_t cpu_count, uint8_t** cpumap, uint32_t* cpumap_size);
kd_threadmap* kdbg_thrmap_init_internal(unsigned int count, unsigned int *mapsize, unsigned int *mapcount);

static int kdbg_enable_typefilter(void);
static int kdbg_disable_typefilter(void);

static int create_buffers(boolean_t);
static void delete_buffers(void);

extern void IOSleep(int);

/* trace enable status */
unsigned int kdebug_enable = 0;

/* A static buffer to record events prior to the start of regular logging */
#define KD_EARLY_BUFFER_MAX      64
static kd_buf           kd_early_buffer[KD_EARLY_BUFFER_MAX];
static int              kd_early_index = 0;
static boolean_t        kd_early_overflow = FALSE;

#define SLOW_NOLOG      0x01
#define SLOW_CHECKS     0x02
#define SLOW_ENTROPY    0x04                    /* Obsolescent */
#define SLOW_CHUD       0x08

#define EVENTS_PER_STORAGE_UNIT         2048
#define MIN_STORAGE_UNITS_PER_CPU       4

#define POINTER_FROM_KDS_PTR(x) (&kd_bufs[x.buffer_index].kdsb_addr[x.offset])

union kds_ptr {
        struct {
                uint32_t buffer_index:21;
                uint16_t offset:11;
        };
        uint32_t raw;
};

struct kd_storage {
        union   kds_ptr kds_next;
        uint32_t kds_bufindx;
        uint32_t kds_bufcnt;
        uint32_t kds_readlast;
        boolean_t kds_lostevents;
        uint64_t  kds_timestamp;

        kd_buf  kds_records[EVENTS_PER_STORAGE_UNIT];
};

#define MAX_BUFFER_SIZE                 (1024 * 1024 * 128)
#define N_STORAGE_UNITS_PER_BUFFER      (MAX_BUFFER_SIZE / sizeof(struct kd_storage))

struct kd_storage_buffers {
        struct  kd_storage      *kdsb_addr;
        uint32_t                kdsb_size;
};

#define KDS_PTR_NULL 0xffffffff
struct kd_storage_buffers *kd_bufs = NULL;
int     n_storage_units = 0;
int     n_storage_buffers = 0;
int     n_storage_threshold = 0;
int     kds_waiter = 0;

#pragma pack(0)
struct kd_bufinfo {
        union  kds_ptr kd_list_head;
        union  kds_ptr kd_list_tail;
        boolean_t kd_lostevents;
        uint32_t _pad;
        uint64_t kd_prev_timebase;
        uint32_t num_bufs;
} __attribute__(( aligned(MAX_CPU_CACHE_LINE_SIZE) ));

struct kd_ctrl_page_t {
        union kds_ptr kds_free_list;
        uint32_t enabled        :1;
        uint32_t _pad0          :31;
        int                     kds_inuse_count;
        uint32_t kdebug_flags;
        uint32_t kdebug_slowcheck;
        /*
         * The number of kd_bufinfo structs allocated may not match the current
         * number of active cpus. We capture the iops list head at initialization
         * which we could use to calculate the number of cpus we allocated data for,
         * unless it happens to be null. To avoid that case, we explicitly also
         * capture a cpu count.
         */
        kd_iop_t* kdebug_iops;
        uint32_t kdebug_cpus;
} kd_ctrl_page = { .kds_free_list = {.raw = KDS_PTR_NULL}, .kdebug_slowcheck = SLOW_NOLOG };

#pragma pack()

struct kd_bufinfo *kdbip = NULL;

#define KDCOPYBUF_COUNT 8192
#define KDCOPYBUF_SIZE  (KDCOPYBUF_COUNT * sizeof(kd_buf))
kd_buf *kdcopybuf = NULL;

boolean_t kdlog_bg_trace = FALSE;
boolean_t kdlog_bg_trace_running = FALSE;
unsigned int bg_nkdbufs = 0;

unsigned int nkdbufs = 0;
unsigned int kdlog_beg=0;
unsigned int kdlog_end=0;
unsigned int kdlog_value1=0;
unsigned int kdlog_value2=0;
unsigned int kdlog_value3=0;
unsigned int kdlog_value4=0;

static lck_spin_t * kdw_spin_lock;
static lck_spin_t * kds_spin_lock;
static lck_mtx_t  * kd_trace_mtx_sysctl;
static lck_grp_t  * kd_trace_mtx_sysctl_grp;
static lck_attr_t * kd_trace_mtx_sysctl_attr;
static lck_grp_attr_t   *kd_trace_mtx_sysctl_grp_attr;

static lck_grp_t       *stackshot_subsys_lck_grp;
static lck_grp_attr_t  *stackshot_subsys_lck_grp_attr;
static lck_attr_t      *stackshot_subsys_lck_attr;
static lck_mtx_t        stackshot_subsys_mutex;

void *stackshot_snapbuf = NULL;

int
stack_snapshot2(pid_t pid, user_addr_t tracebuf, uint32_t tracebuf_size, uint32_t flags, uint32_t dispatch_offset, int32_t *retval);

int  
stack_snapshot_from_kernel(pid_t pid, void *buf, uint32_t size, uint32_t flags, unsigned *bytesTraced);
extern void
kdp_snapshot_preflight(int pid, void  *tracebuf, uint32_t tracebuf_size, uint32_t flags, uint32_t dispatch_offset);

extern int
kdp_stack_snapshot_geterror(void);
extern unsigned int
kdp_stack_snapshot_bytes_traced(void);

kd_threadmap *kd_mapptr = 0;
unsigned int kd_mapsize = 0;
unsigned int kd_mapcount = 0;

off_t   RAW_file_offset = 0;
int     RAW_file_written = 0;

#define RAW_FLUSH_SIZE  (2 * 1024 * 1024)

pid_t global_state_pid = -1;       /* Used to control exclusive use of kd_buffer */

#define DBG_FUNC_MASK   0xfffffffc

/*  TODO: move to kdebug.h */
#define CLASS_MASK      0xff000000
#define CLASS_OFFSET    24
#define SUBCLASS_MASK   0x00ff0000
#define SUBCLASS_OFFSET 16
#define CSC_MASK        0xffff0000      /*  class and subclass mask */
#define CSC_OFFSET      SUBCLASS_OFFSET

#define EXTRACT_CLASS(debugid)          ( (uint8_t) ( ((debugid) & CLASS_MASK   ) >> CLASS_OFFSET    ) )
#define EXTRACT_SUBCLASS(debugid)       ( (uint8_t) ( ((debugid) & SUBCLASS_MASK) >> SUBCLASS_OFFSET ) )
#define EXTRACT_CSC(debugid)            ( (uint16_t)( ((debugid) & CSC_MASK     ) >> CSC_OFFSET      ) )

#define INTERRUPT       0x01050000
#define MACH_vmfault    0x01300008
#define BSC_SysCall     0x040c0000
#define MACH_SysCall    0x010c0000
#define DBG_SCALL_MASK  0xffff0000

/* task to string structure */
struct tts
{
  task_t    task;            /* from procs task */
  pid_t     pid;             /* from procs p_pid  */
  char      task_comm[20];   /* from procs p_comm */
};

typedef struct tts tts_t;

struct krt
{
        kd_threadmap *map;    /* pointer to the map buffer */
        int count;
        int maxcount;
        struct tts *atts;
};

typedef struct krt krt_t;

/* This is for the CHUD toolkit call */
typedef void (*kd_chudhook_fn) (uint32_t debugid, uintptr_t arg1,
                                uintptr_t arg2, uintptr_t arg3,
                                uintptr_t arg4, uintptr_t arg5);

volatile kd_chudhook_fn kdebug_chudhook = 0;   /* pointer to CHUD toolkit function */

__private_extern__ void stackshot_lock_init( void );

static uint8_t *type_filter_bitmap;

/*
 * This allows kperf to swap out the global state pid when kperf ownership is
 * passed from one process to another. It checks the old global state pid so
 * that kperf can't accidentally steal control of trace when a non-kperf trace user has
 * control of trace.
 */
void
kdbg_swap_global_state_pid(pid_t old_pid, pid_t new_pid);

void
kdbg_swap_global_state_pid(pid_t old_pid, pid_t new_pid)
{
        if (!(kd_ctrl_page.kdebug_flags & KDBG_LOCKINIT))
                return;

        lck_mtx_lock(kd_trace_mtx_sysctl);

        if (old_pid == global_state_pid)
                global_state_pid = new_pid;

        lck_mtx_unlock(kd_trace_mtx_sysctl);
}

static uint32_t
kdbg_cpu_count(boolean_t early_trace)
{
        if (early_trace) {
                /*
                 * we've started tracing before the IOKit has even
                 * started running... just use the static max value
                 */
                return max_ncpus;
        }

        host_basic_info_data_t hinfo;
        mach_msg_type_number_t count = HOST_BASIC_INFO_COUNT;
        host_info((host_t)1 /* BSD_HOST */, HOST_BASIC_INFO, (host_info_t)&hinfo, &count);
        assert(hinfo.logical_cpu_max > 0);
        return hinfo.logical_cpu_max;
}

#if MACH_ASSERT
#endif /* MACH_ASSERT */

static void
kdbg_iop_list_callback(kd_iop_t* iop, kd_callback_type type, void* arg)
{
        while (iop) {
                iop->callback.func(iop->callback.context, type, arg);
                iop = iop->next;
        }
}

static void
kdbg_set_tracing_enabled(boolean_t enabled, uint32_t trace_type)
{
        int s = ml_set_interrupts_enabled(FALSE);
        lck_spin_lock(kds_spin_lock);
        if (enabled) {
                kdebug_enable |= trace_type;
                kd_ctrl_page.kdebug_slowcheck &= ~SLOW_NOLOG;
                kd_ctrl_page.enabled = 1;
                commpage_update_kdebug_enable();
        } else {
                kdebug_enable &= ~(KDEBUG_ENABLE_TRACE|KDEBUG_ENABLE_PPT);
                kd_ctrl_page.kdebug_slowcheck |= SLOW_NOLOG;
                kd_ctrl_page.enabled = 0;
                commpage_update_kdebug_enable();
        }
        lck_spin_unlock(kds_spin_lock);
        ml_set_interrupts_enabled(s);

        if (enabled) {
                kdbg_iop_list_callback(kd_ctrl_page.kdebug_iops, KD_CALLBACK_KDEBUG_ENABLED, NULL);
        } else {
                /*
                 * If you do not flush the IOP trace buffers, they can linger
                 * for a considerable period; consider code which disables and
                 * deallocates without a final sync flush.
                 */
                kdbg_iop_list_callback(kd_ctrl_page.kdebug_iops, KD_CALLBACK_KDEBUG_DISABLED, NULL);
                kdbg_iop_list_callback(kd_ctrl_page.kdebug_iops, KD_CALLBACK_SYNC_FLUSH, NULL);
        }
}

static void
kdbg_set_flags(int slowflag, int enableflag, boolean_t enabled)
{
        int s = ml_set_interrupts_enabled(FALSE);
        lck_spin_lock(kds_spin_lock);

        if (enabled) {
                kd_ctrl_page.kdebug_slowcheck |= slowflag;
                kdebug_enable |= enableflag;
        } else {
                kd_ctrl_page.kdebug_slowcheck &= ~slowflag;
                kdebug_enable &= ~enableflag;
        }
        
        lck_spin_unlock(kds_spin_lock);
        ml_set_interrupts_enabled(s);
}

void
disable_wrap(uint32_t *old_slowcheck, uint32_t *old_flags)
{
        int s = ml_set_interrupts_enabled(FALSE);
        lck_spin_lock(kds_spin_lock);

        *old_slowcheck = kd_ctrl_page.kdebug_slowcheck;
        *old_flags = kd_ctrl_page.kdebug_flags;

        kd_ctrl_page.kdebug_flags &= ~KDBG_WRAPPED;
        kd_ctrl_page.kdebug_flags |= KDBG_NOWRAP;

        lck_spin_unlock(kds_spin_lock);
        ml_set_interrupts_enabled(s);
}

void
enable_wrap(uint32_t old_slowcheck, boolean_t lostevents)
{
        int s = ml_set_interrupts_enabled(FALSE);
        lck_spin_lock(kds_spin_lock);

        kd_ctrl_page.kdebug_flags &= ~KDBG_NOWRAP;

        if ( !(old_slowcheck & SLOW_NOLOG))
                kd_ctrl_page.kdebug_slowcheck &= ~SLOW_NOLOG;

        if (lostevents == TRUE)
                kd_ctrl_page.kdebug_flags |= KDBG_WRAPPED;

        lck_spin_unlock(kds_spin_lock);
        ml_set_interrupts_enabled(s);
}

static int
create_buffers(boolean_t early_trace)
{
        int     i;
        int     p_buffer_size;
        int     f_buffer_size;
        int     f_buffers;
        int     error = 0;

        /*
         * For the duration of this allocation, trace code will only reference
         * kdebug_iops. Any iops registered after this enabling will not be
         * messaged until the buffers are reallocated.
         *
         * TLDR; Must read kd_iops once and only once!
         */
        kd_ctrl_page.kdebug_iops = kd_iops;


        /*
         * If the list is valid, it is sorted, newest -> oldest. Each iop entry
         * has a cpu_id of "the older entry + 1", so the highest cpu_id will
         * be the list head + 1.
         */

        kd_ctrl_page.kdebug_cpus = kd_ctrl_page.kdebug_iops ? kd_ctrl_page.kdebug_iops->cpu_id + 1 : kdbg_cpu_count(early_trace);

        if (kmem_alloc(kernel_map, (vm_offset_t *)&kdbip, sizeof(struct kd_bufinfo) * kd_ctrl_page.kdebug_cpus) != KERN_SUCCESS) {
                error = ENOSPC;
                goto out;
        }

        if (nkdbufs < (kd_ctrl_page.kdebug_cpus * EVENTS_PER_STORAGE_UNIT * MIN_STORAGE_UNITS_PER_CPU))
                n_storage_units = kd_ctrl_page.kdebug_cpus * MIN_STORAGE_UNITS_PER_CPU;
        else
                n_storage_units = nkdbufs / EVENTS_PER_STORAGE_UNIT;

        nkdbufs = n_storage_units * EVENTS_PER_STORAGE_UNIT;

        f_buffers = n_storage_units / N_STORAGE_UNITS_PER_BUFFER;
        n_storage_buffers = f_buffers;

        f_buffer_size = N_STORAGE_UNITS_PER_BUFFER * sizeof(struct kd_storage);
        p_buffer_size = (n_storage_units % N_STORAGE_UNITS_PER_BUFFER) * sizeof(struct kd_storage);

        if (p_buffer_size)
                n_storage_buffers++;

        kd_bufs = NULL;

        if (kdcopybuf == 0) {
                if (kmem_alloc(kernel_map, (vm_offset_t *)&kdcopybuf, (vm_size_t)KDCOPYBUF_SIZE) != KERN_SUCCESS) {
                        error = ENOSPC;
                        goto out;
                }
        }
        if (kmem_alloc(kernel_map, (vm_offset_t *)&kd_bufs, (vm_size_t)(n_storage_buffers * sizeof(struct kd_storage_buffers))) != KERN_SUCCESS) {
                error = ENOSPC;
                goto out;
        }
        bzero(kd_bufs, n_storage_buffers * sizeof(struct kd_storage_buffers));

        for (i = 0; i < f_buffers; i++) {
                if (kmem_alloc(kernel_map, (vm_offset_t *)&kd_bufs[i].kdsb_addr, (vm_size_t)f_buffer_size) != KERN_SUCCESS) {
                        error = ENOSPC;
                        goto out;
                }
                bzero(kd_bufs[i].kdsb_addr, f_buffer_size);

                kd_bufs[i].kdsb_size = f_buffer_size;
        }
        if (p_buffer_size) {
                if (kmem_alloc(kernel_map, (vm_offset_t *)&kd_bufs[i].kdsb_addr, (vm_size_t)p_buffer_size) != KERN_SUCCESS) {
                        error = ENOSPC;
                        goto out;
                }
                bzero(kd_bufs[i].kdsb_addr, p_buffer_size);

                kd_bufs[i].kdsb_size = p_buffer_size;
        }
        n_storage_units = 0;

        for (i = 0; i < n_storage_buffers; i++) {
                struct kd_storage *kds;
                int     n_elements;
                int     n;

                n_elements = kd_bufs[i].kdsb_size / sizeof(struct kd_storage);
                kds = kd_bufs[i].kdsb_addr;

                for (n = 0; n < n_elements; n++) {
                        kds[n].kds_next.buffer_index = kd_ctrl_page.kds_free_list.buffer_index;
                        kds[n].kds_next.offset = kd_ctrl_page.kds_free_list.offset;

                        kd_ctrl_page.kds_free_list.buffer_index = i;
                        kd_ctrl_page.kds_free_list.offset = n;
                }
                n_storage_units += n_elements;
        }

        bzero((char *)kdbip, sizeof(struct kd_bufinfo) * kd_ctrl_page.kdebug_cpus);

        for (i = 0; i < (int)kd_ctrl_page.kdebug_cpus; i++) {
                kdbip[i].kd_list_head.raw = KDS_PTR_NULL;
                kdbip[i].kd_list_tail.raw = KDS_PTR_NULL;
                kdbip[i].kd_lostevents = FALSE;
                kdbip[i].num_bufs = 0;
        }
        
        kd_ctrl_page.kdebug_flags |= KDBG_BUFINIT;

        kd_ctrl_page.kds_inuse_count = 0;
        n_storage_threshold = n_storage_units / 2;
out:
        if (error)
                delete_buffers();

        return(error);
}

static void
delete_buffers(void)
{
        int i;
        
        if (kd_bufs) {
                for (i = 0; i < n_storage_buffers; i++) {
                        if (kd_bufs[i].kdsb_addr) {
                                kmem_free(kernel_map, (vm_offset_t)kd_bufs[i].kdsb_addr, (vm_size_t)kd_bufs[i].kdsb_size);
                        }
                }
                kmem_free(kernel_map, (vm_offset_t)kd_bufs, (vm_size_t)(n_storage_buffers * sizeof(struct kd_storage_buffers)));

                kd_bufs = NULL;
                n_storage_buffers = 0;
        }
        if (kdcopybuf) {
                kmem_free(kernel_map, (vm_offset_t)kdcopybuf, KDCOPYBUF_SIZE);

                kdcopybuf = NULL;
        }
        kd_ctrl_page.kds_free_list.raw = KDS_PTR_NULL;

        if (kdbip) {
                kmem_free(kernel_map, (vm_offset_t)kdbip, sizeof(struct kd_bufinfo) * kd_ctrl_page.kdebug_cpus);
                
                kdbip = NULL;
        }
        kd_ctrl_page.kdebug_iops = NULL;
        kd_ctrl_page.kdebug_cpus = 0;
        kd_ctrl_page.kdebug_flags &= ~KDBG_BUFINIT;
}

void
release_storage_unit(int cpu, uint32_t kdsp_raw)
{
        int s = 0;
        struct  kd_storage *kdsp_actual;
        struct kd_bufinfo *kdbp;
        union kds_ptr kdsp;

        kdsp.raw = kdsp_raw;

        s = ml_set_interrupts_enabled(FALSE);
        lck_spin_lock(kds_spin_lock);

        kdbp = &kdbip[cpu];

        if (kdsp.raw == kdbp->kd_list_head.raw) {
                /*
                 * it's possible for the storage unit pointed to
                 * by kdsp to have already been stolen... so
                 * check to see if it's still the head of the list
                 * now that we're behind the lock that protects 
                 * adding and removing from the queue...
                 * since we only ever release and steal units from
                 * that position, if it's no longer the head
                 * we having nothing to do in this context
                 */
                kdsp_actual = POINTER_FROM_KDS_PTR(kdsp);
                kdbp->kd_list_head = kdsp_actual->kds_next;

                kdsp_actual->kds_next = kd_ctrl_page.kds_free_list;
                kd_ctrl_page.kds_free_list = kdsp;

                kd_ctrl_page.kds_inuse_count--;
        }
        lck_spin_unlock(kds_spin_lock);
        ml_set_interrupts_enabled(s);
}


boolean_t
allocate_storage_unit(int cpu)
{
        union   kds_ptr kdsp;
        struct  kd_storage *kdsp_actual, *kdsp_next_actual;
        struct  kd_bufinfo *kdbp, *kdbp_vict, *kdbp_try;
        uint64_t        oldest_ts, ts;
        boolean_t       retval = TRUE;
        int                     s = 0;
                
        s = ml_set_interrupts_enabled(FALSE);
        lck_spin_lock(kds_spin_lock);

        kdbp = &kdbip[cpu];

        /* If someone beat us to the allocate, return success */
        if (kdbp->kd_list_tail.raw != KDS_PTR_NULL) {
                kdsp_actual = POINTER_FROM_KDS_PTR(kdbp->kd_list_tail);

                if (kdsp_actual->kds_bufindx < EVENTS_PER_STORAGE_UNIT)
                        goto out;
        }
        
        if ((kdsp = kd_ctrl_page.kds_free_list).raw != KDS_PTR_NULL) {
                kdsp_actual = POINTER_FROM_KDS_PTR(kdsp);
                kd_ctrl_page.kds_free_list = kdsp_actual->kds_next;

                kd_ctrl_page.kds_inuse_count++;
        } else {
                if (kd_ctrl_page.kdebug_flags & KDBG_NOWRAP) {
                        kd_ctrl_page.kdebug_slowcheck |= SLOW_NOLOG;
                        kdbp->kd_lostevents = TRUE;
                        retval = FALSE;
                        goto out;
                }
                kdbp_vict = NULL;
                oldest_ts = (uint64_t)-1;

                for (kdbp_try = &kdbip[0]; kdbp_try < &kdbip[kd_ctrl_page.kdebug_cpus]; kdbp_try++) {

                        if (kdbp_try->kd_list_head.raw == KDS_PTR_NULL) {
                                /*
                                 * no storage unit to steal
                                 */
                                continue;
                        }

                        kdsp_actual = POINTER_FROM_KDS_PTR(kdbp_try->kd_list_head);

                        if (kdsp_actual->kds_bufcnt < EVENTS_PER_STORAGE_UNIT) {
                                /*
                                 * make sure we don't steal the storage unit
                                 * being actively recorded to...  need to
                                 * move on because we don't want an out-of-order
                                 * set of events showing up later
                                 */
                                continue;
                        }
                        ts = kdbg_get_timestamp(&kdsp_actual->kds_records[0]);

                        if (ts < oldest_ts) {
                                /*
                                 * when 'wrapping', we want to steal the
                                 * storage unit that has the 'earliest' time
                                 * associated with it (first event time)
                                 */
                                oldest_ts = ts;
                                kdbp_vict = kdbp_try;
                        }
                }
                if (kdbp_vict == NULL) {
                        kdebug_enable = 0;
                        kd_ctrl_page.enabled = 0;
                        commpage_update_kdebug_enable();
                        retval = FALSE;
                        goto out;
                }
                kdsp = kdbp_vict->kd_list_head;
                kdsp_actual = POINTER_FROM_KDS_PTR(kdsp);
                kdbp_vict->kd_list_head = kdsp_actual->kds_next;

                if (kdbp_vict->kd_list_head.raw != KDS_PTR_NULL) {
                        kdsp_next_actual = POINTER_FROM_KDS_PTR(kdbp_vict->kd_list_head);
                        kdsp_next_actual->kds_lostevents = TRUE;
                } else
                        kdbp_vict->kd_lostevents = TRUE;

                kd_ctrl_page.kdebug_flags |= KDBG_WRAPPED;
        }
        kdsp_actual->kds_timestamp = mach_absolute_time();
        kdsp_actual->kds_next.raw = KDS_PTR_NULL;
        kdsp_actual->kds_bufcnt   = 0;
        kdsp_actual->kds_readlast = 0;

        kdsp_actual->kds_lostevents = kdbp->kd_lostevents;
        kdbp->kd_lostevents = FALSE;
        kdsp_actual->kds_bufindx  = 0;

        if (kdbp->kd_list_head.raw == KDS_PTR_NULL)
                kdbp->kd_list_head = kdsp;
        else
                POINTER_FROM_KDS_PTR(kdbp->kd_list_tail)->kds_next = kdsp;
        kdbp->kd_list_tail = kdsp;
out:
        lck_spin_unlock(kds_spin_lock);
        ml_set_interrupts_enabled(s);

        return (retval);
}

int
kernel_debug_register_callback(kd_callback_t callback)
{
        kd_iop_t* iop;
        if (kmem_alloc(kernel_map, (vm_offset_t *)&iop, sizeof(kd_iop_t)) == KERN_SUCCESS) {
                memcpy(&iop->callback, &callback, sizeof(kd_callback_t));
                
                /*
                 * <rdar://problem/13351477> Some IOP clients are not providing a name.
                 *
                 * Remove when fixed.
                 */
                {
                        boolean_t is_valid_name = FALSE;
                        for (uint32_t length=0; length<sizeof(callback.iop_name); ++length) {
                                /* This is roughly isprintable(c) */
                                if (callback.iop_name[length] > 0x20 && callback.iop_name[length] < 0x7F)
                                        continue;
                                if (callback.iop_name[length] == 0) {
                                        if (length)
                                                is_valid_name = TRUE;
                                        break;
                                }
                        }
                        
                        if (!is_valid_name) {
                                strlcpy(iop->callback.iop_name, "IOP-???", sizeof(iop->callback.iop_name));
                        }
                }

                iop->last_timestamp = 0;
                
                do {
                        /*
                         * We use two pieces of state, the old list head
                         * pointer, and the value of old_list_head->cpu_id.
                         * If we read kd_iops more than once, it can change
                         * between reads.
                         *
                         * TLDR; Must not read kd_iops more than once per loop.
                         */
                        iop->next = kd_iops;
                        iop->cpu_id = iop->next ? (iop->next->cpu_id+1) : kdbg_cpu_count(FALSE);

                        /*
                         * Header says OSCompareAndSwapPtr has a memory barrier
                         */
                } while (!OSCompareAndSwapPtr(iop->next, iop, (void* volatile*)&kd_iops));

                return iop->cpu_id;
        }

        return 0;
}

void
kernel_debug_enter(
        uint32_t        coreid,
        uint32_t        debugid,
        uint64_t        timestamp,
        uintptr_t       arg1,
        uintptr_t       arg2,
        uintptr_t       arg3,
        uintptr_t       arg4,
        uintptr_t       threadid
        )
{
        uint32_t        bindx;
        kd_buf          *kd;
        struct kd_bufinfo *kdbp;
        struct kd_storage *kdsp_actual;
        union  kds_ptr kds_raw;

        if (kd_ctrl_page.kdebug_slowcheck) {

                if ( (kd_ctrl_page.kdebug_slowcheck & SLOW_NOLOG) || !(kdebug_enable & (KDEBUG_ENABLE_TRACE|KDEBUG_ENABLE_PPT)))
                        goto out1;
        
                if (kd_ctrl_page.kdebug_flags & KDBG_TYPEFILTER_CHECK) {
                        if (isset(type_filter_bitmap, EXTRACT_CSC(debugid))) 
                                goto record_event;
                        goto out1;
                }
                else if (kd_ctrl_page.kdebug_flags & KDBG_RANGECHECK) {
                        if (debugid >= kdlog_beg && debugid <= kdlog_end)
                                goto record_event;
                        goto out1;
                }
                else if (kd_ctrl_page.kdebug_flags & KDBG_VALCHECK) {
                        if ((debugid & DBG_FUNC_MASK) != kdlog_value1 &&
                                (debugid & DBG_FUNC_MASK) != kdlog_value2 &&
                                (debugid & DBG_FUNC_MASK) != kdlog_value3 &&
                                (debugid & DBG_FUNC_MASK) != kdlog_value4)
                                goto out1;
                }
        }
        
record_event:

        disable_preemption();

        if (kd_ctrl_page.enabled == 0)
                goto out;

        kdbp = &kdbip[coreid];
        timestamp &= KDBG_TIMESTAMP_MASK;

#if KDEBUG_MOJO_TRACE
        if (kdebug_enable & KDEBUG_ENABLE_SERIAL)
                kdebug_serial_print(coreid, debugid, timestamp,
                                    arg1, arg2, arg3, arg4, threadid);
#endif

retry_q:
        kds_raw = kdbp->kd_list_tail;

        if (kds_raw.raw != KDS_PTR_NULL) {
                kdsp_actual = POINTER_FROM_KDS_PTR(kds_raw);
                bindx = kdsp_actual->kds_bufindx;
        } else
                kdsp_actual = NULL;
        
        if (kdsp_actual == NULL || bindx >= EVENTS_PER_STORAGE_UNIT) {
                if (allocate_storage_unit(coreid) == FALSE) {
                        /*
                         * this can only happen if wrapping
                         * has been disabled
                         */
                        goto out;
                }
                goto retry_q;
        }
        if ( !OSCompareAndSwap(bindx, bindx + 1, &kdsp_actual->kds_bufindx))
                goto retry_q;

        // IOP entries can be allocated before xnu allocates and inits the buffer
        if (timestamp < kdsp_actual->kds_timestamp)
                kdsp_actual->kds_timestamp = timestamp;

        kd = &kdsp_actual->kds_records[bindx];

        kd->debugid = debugid;
        kd->arg1 = arg1;
        kd->arg2 = arg2;
        kd->arg3 = arg3;
        kd->arg4 = arg4;
        kd->arg5 = threadid;
                  
        kdbg_set_timestamp_and_cpu(kd, timestamp, coreid);

        OSAddAtomic(1, &kdsp_actual->kds_bufcnt);
out:
        enable_preemption();
out1:
        if ((kds_waiter && kd_ctrl_page.kds_inuse_count >= n_storage_threshold)) {
                boolean_t need_kds_wakeup = FALSE;
                int     s;

                /*
                 * try to take the lock here to synchronize with the
                 * waiter entering the blocked state... use the try
                 * mode to prevent deadlocks caused by re-entering this
                 * routine due to various trace points triggered in the
                 * lck_spin_sleep_xxxx routines used to actually enter
                 * our wait condition... no problem if we fail,
                 * there will be lots of additional events coming in that
                 * will eventually succeed in grabbing this lock
                 */
                s = ml_set_interrupts_enabled(FALSE);

                if (lck_spin_try_lock(kdw_spin_lock)) {

                        if (kds_waiter && kd_ctrl_page.kds_inuse_count >= n_storage_threshold) {
                                kds_waiter = 0;
                                need_kds_wakeup = TRUE;
                        }
                        lck_spin_unlock(kdw_spin_lock);

                        ml_set_interrupts_enabled(s);
                        
                        if (need_kds_wakeup == TRUE)
                                wakeup(&kds_waiter);
                }
        }
}



static void
kernel_debug_internal(
        uint32_t        debugid,
        uintptr_t       arg1,
        uintptr_t       arg2,
        uintptr_t       arg3,
        uintptr_t       arg4,
        uintptr_t       arg5)
{
        struct proc     *curproc;
        uint64_t        now;
        uint32_t        bindx;
        boolean_t       s;
        kd_buf          *kd;
        int             cpu;
        struct kd_bufinfo *kdbp;
        struct kd_storage *kdsp_actual;
        union  kds_ptr kds_raw;

        

        if (kd_ctrl_page.kdebug_slowcheck) {

                if (kdebug_enable & KDEBUG_ENABLE_CHUD) {
                        kd_chudhook_fn chudhook;
                        /*
                         * Mask interrupts to minimize the interval across
                         * which the driver providing the hook could be
                         * unloaded.
                         */
                        s = ml_set_interrupts_enabled(FALSE);
                        chudhook = kdebug_chudhook;
                        if (chudhook)
                                chudhook(debugid, arg1, arg2, arg3, arg4, arg5);
                        ml_set_interrupts_enabled(s);
                }
                if ( (kd_ctrl_page.kdebug_slowcheck & SLOW_NOLOG) || !(kdebug_enable & (KDEBUG_ENABLE_TRACE|KDEBUG_ENABLE_PPT)))
                        goto out1;
        
                if ( !ml_at_interrupt_context()) {
                        if (kd_ctrl_page.kdebug_flags & KDBG_PIDCHECK) {
                                /*
                                 * If kdebug flag is not set for current proc, return
                                 */
                                curproc = current_proc();

                                if ((curproc && !(curproc->p_kdebug)) &&
                                    ((debugid & 0xffff0000) != (MACHDBG_CODE(DBG_MACH_SCHED, 0) | DBG_FUNC_NONE)) &&
                                      (debugid >> 24 != DBG_TRACE))
                                        goto out1;
                        }
                        else if (kd_ctrl_page.kdebug_flags & KDBG_PIDEXCLUDE) {
                                /*
                                 * If kdebug flag is set for current proc, return
                                 */
                                curproc = current_proc();

                                if ((curproc && curproc->p_kdebug) &&
                                    ((debugid & 0xffff0000) != (MACHDBG_CODE(DBG_MACH_SCHED, 0) | DBG_FUNC_NONE)) &&
                                      (debugid >> 24 != DBG_TRACE))
                                        goto out1;
                        }
                }

                if (kd_ctrl_page.kdebug_flags & KDBG_TYPEFILTER_CHECK) {
                        /* Always record trace system info */
                        if (EXTRACT_CLASS(debugid) == DBG_TRACE)
                                goto record_event;

                        if (isset(type_filter_bitmap, EXTRACT_CSC(debugid))) 
                                goto record_event;
                        goto out1;
                }
                else if (kd_ctrl_page.kdebug_flags & KDBG_RANGECHECK) {
                        /* Always record trace system info */
                        if (EXTRACT_CLASS(debugid) == DBG_TRACE)
                                goto record_event;
                                
                        if (debugid < kdlog_beg || debugid > kdlog_end)
                                goto out1;
                }
                else if (kd_ctrl_page.kdebug_flags & KDBG_VALCHECK) {
                        /* Always record trace system info */
                        if (EXTRACT_CLASS(debugid) == DBG_TRACE)
                                goto record_event;
                
                        if ((debugid & DBG_FUNC_MASK) != kdlog_value1 &&
                            (debugid & DBG_FUNC_MASK) != kdlog_value2 &&
                            (debugid & DBG_FUNC_MASK) != kdlog_value3 &&
                            (debugid & DBG_FUNC_MASK) != kdlog_value4)
                                goto out1;
                }
        }
record_event:
        disable_preemption();

        if (kd_ctrl_page.enabled == 0)
                goto out;

        cpu = cpu_number();
        kdbp = &kdbip[cpu];

#if KDEBUG_MOJO_TRACE
        if (kdebug_enable & KDEBUG_ENABLE_SERIAL)
                kdebug_serial_print(cpu, debugid,
                                    mach_absolute_time() & KDBG_TIMESTAMP_MASK,
                                    arg1, arg2, arg3, arg4, arg5);
#endif

retry_q:
        kds_raw = kdbp->kd_list_tail;

        if (kds_raw.raw != KDS_PTR_NULL) {
                kdsp_actual = POINTER_FROM_KDS_PTR(kds_raw);
                bindx = kdsp_actual->kds_bufindx;
        } else
                kdsp_actual = NULL;
        
        if (kdsp_actual == NULL || bindx >= EVENTS_PER_STORAGE_UNIT) {
                if (allocate_storage_unit(cpu) == FALSE) {
                        /*
                         * this can only happen if wrapping
                         * has been disabled
                         */
                        goto out;
                }
                goto retry_q;
        }
        now = mach_absolute_time() & KDBG_TIMESTAMP_MASK;

        if ( !OSCompareAndSwap(bindx, bindx + 1, &kdsp_actual->kds_bufindx))
                goto retry_q;

        kd = &kdsp_actual->kds_records[bindx];

        kd->debugid = debugid;
        kd->arg1 = arg1;
        kd->arg2 = arg2;
        kd->arg3 = arg3;
        kd->arg4 = arg4;
        kd->arg5 = arg5;
                  
        kdbg_set_timestamp_and_cpu(kd, now, cpu);

        OSAddAtomic(1, &kdsp_actual->kds_bufcnt);
out:
        enable_preemption();
out1:
        if (kds_waiter && kd_ctrl_page.kds_inuse_count >= n_storage_threshold) {
                uint32_t        etype;
                uint32_t        stype;
                
                etype = debugid & DBG_FUNC_MASK;
                stype = debugid & DBG_SCALL_MASK;

                if (etype == INTERRUPT || etype == MACH_vmfault ||
                    stype == BSC_SysCall || stype == MACH_SysCall) {

                        boolean_t need_kds_wakeup = FALSE;

                        /*
                         * try to take the lock here to synchronize with the
                         * waiter entering the blocked state... use the try
                         * mode to prevent deadlocks caused by re-entering this
                         * routine due to various trace points triggered in the
                         * lck_spin_sleep_xxxx routines used to actually enter
                         * one of our 2 wait conditions... no problem if we fail,
                         * there will be lots of additional events coming in that
                         * will eventually succeed in grabbing this lock
                         */
                        s = ml_set_interrupts_enabled(FALSE);

                        if (lck_spin_try_lock(kdw_spin_lock)) {

                                if (kds_waiter && kd_ctrl_page.kds_inuse_count >= n_storage_threshold) {
                                        kds_waiter = 0;
                                        need_kds_wakeup = TRUE;
                                }
                                lck_spin_unlock(kdw_spin_lock);
                        }
                        ml_set_interrupts_enabled(s);
                        
                        if (need_kds_wakeup == TRUE)
                                wakeup(&kds_waiter);
                }
        }
}

void
kernel_debug(
        uint32_t        debugid,
        uintptr_t       arg1,
        uintptr_t       arg2,
        uintptr_t       arg3,
        uintptr_t       arg4,
        __unused uintptr_t arg5)
{
        kernel_debug_internal(debugid, arg1, arg2, arg3, arg4, (uintptr_t)thread_tid(current_thread()));
}

void
kernel_debug1(
        uint32_t        debugid,
        uintptr_t       arg1,
        uintptr_t       arg2,
        uintptr_t       arg3,
        uintptr_t       arg4,
        uintptr_t       arg5)
{
        kernel_debug_internal(debugid, arg1, arg2, arg3, arg4, arg5);
}

void
kernel_debug_string(const char *message)
{
        uintptr_t arg[4] = {0, 0, 0, 0};

        /* Stuff the message string in the args and log it. */
        strncpy((char *)arg, message, MIN(sizeof(arg), strlen(message)));
        KERNEL_DEBUG_EARLY(
                TRACE_INFO_STRING,
                arg[0], arg[1], arg[2], arg[3]);
}

extern int      master_cpu;             /* MACH_KERNEL_PRIVATE */
/*
 * Used prior to start_kern_tracing() being called.
 * Log temporarily into a static buffer.
 */
void
kernel_debug_early(
        uint32_t        debugid,
        uintptr_t       arg1,
        uintptr_t       arg2,
        uintptr_t       arg3,
        uintptr_t       arg4)
{
        /* If tracing is already initialized, use it */
        if (nkdbufs) {
                KERNEL_DEBUG_CONSTANT(debugid, arg1, arg2, arg3, arg4, 0);
                return;
        }

        /* Do nothing if the buffer is full or we're not on the boot cpu */ 
        kd_early_overflow = kd_early_index >= KD_EARLY_BUFFER_MAX;
        if (kd_early_overflow ||
            cpu_number() != master_cpu)
                return;

        kd_early_buffer[kd_early_index].debugid = debugid;
        kd_early_buffer[kd_early_index].timestamp = mach_absolute_time();
        kd_early_buffer[kd_early_index].arg1 = arg1;
        kd_early_buffer[kd_early_index].arg2 = arg2;
        kd_early_buffer[kd_early_index].arg3 = arg3;
        kd_early_buffer[kd_early_index].arg4 = arg4;
        kd_early_buffer[kd_early_index].arg5 = 0;
        kd_early_index++;
}

/*
 * Transfen the contents of the temporary buffer into the trace buffers.
 * Precede that by logging the rebase time (offset) - the TSC-based time (in ns)
 * when mach_absolute_time is set to 0.
 */
static void
kernel_debug_early_end(void)
{
        int     i;

        if (cpu_number() != master_cpu)
                panic("kernel_debug_early_end() not call on boot processor");

        /* Fake sentinel marking the start of kernel time relative to TSC */
        kernel_debug_enter(
                0,
                TRACE_TIMESTAMPS,
                0,
                (uint32_t)(tsc_rebase_abs_time >> 32),
                (uint32_t)tsc_rebase_abs_time,
                0,
                0,
                0);
        for (i = 0; i < kd_early_index; i++) {
                kernel_debug_enter(
                        0,
                        kd_early_buffer[i].debugid,
                        kd_early_buffer[i].timestamp,
                        kd_early_buffer[i].arg1,
                        kd_early_buffer[i].arg2,
                        kd_early_buffer[i].arg3,
                        kd_early_buffer[i].arg4,
                        0);
        }

        /* Cut events-lost event on overflow */
        if (kd_early_overflow)
                KERNEL_DEBUG_CONSTANT(
                        TRACE_LOST_EVENTS, 0, 0, 0, 0, 0);

        /* This trace marks the start of kernel tracing */
        kernel_debug_string("early trace done");
}

/*
 * Support syscall SYS_kdebug_trace. U64->K32 args may get truncated in kdebug_trace64
 */
int
kdebug_trace(struct proc *p, struct kdebug_trace_args *uap, int32_t *retval)
{
        struct kdebug_trace64_args uap64;

        uap64.code = uap->code;
        uap64.arg1 = uap->arg1;
        uap64.arg2 = uap->arg2;
        uap64.arg3 = uap->arg3;
        uap64.arg4 = uap->arg4;

        return kdebug_trace64(p, &uap64, retval);
}

/*
 * Support syscall SYS_kdebug_trace64. 64-bit args on K32 will get truncated to fit in 32-bit record format.
 */
int kdebug_trace64(__unused struct proc *p, struct kdebug_trace64_args *uap, __unused int32_t *retval)
{
        uint8_t code_class;

        /*
         * Not all class are supported for injection from userspace, especially ones used by the core
         * kernel tracing infrastructure.
         */
        code_class = EXTRACT_CLASS(uap->code);

        switch (code_class) {
                case DBG_TRACE:
                        return EPERM;
        }

        if ( __probable(kdebug_enable == 0) )
                return(0); 

        kernel_debug_internal(uap->code, (uintptr_t)uap->arg1, (uintptr_t)uap->arg2, (uintptr_t)uap->arg3, (uintptr_t)uap->arg4, (uintptr_t)thread_tid(current_thread()));

        return(0);
}

static void
kdbg_lock_init(void)
{
        if (kd_ctrl_page.kdebug_flags & KDBG_LOCKINIT)
                return;
        
        /*
         * allocate lock group attribute and group
         */
        kd_trace_mtx_sysctl_grp_attr = lck_grp_attr_alloc_init();
        kd_trace_mtx_sysctl_grp = lck_grp_alloc_init("kdebug", kd_trace_mtx_sysctl_grp_attr);
                
        /*
         * allocate the lock attribute
         */
        kd_trace_mtx_sysctl_attr = lck_attr_alloc_init();


        /*
         * allocate and initialize mutex's
         */
        kd_trace_mtx_sysctl = lck_mtx_alloc_init(kd_trace_mtx_sysctl_grp, kd_trace_mtx_sysctl_attr);
        kds_spin_lock = lck_spin_alloc_init(kd_trace_mtx_sysctl_grp, kd_trace_mtx_sysctl_attr);
        kdw_spin_lock = lck_spin_alloc_init(kd_trace_mtx_sysctl_grp, kd_trace_mtx_sysctl_attr);

        kd_ctrl_page.kdebug_flags |= KDBG_LOCKINIT;
}


int
kdbg_bootstrap(boolean_t early_trace)
{
        kd_ctrl_page.kdebug_flags &= ~KDBG_WRAPPED;

        return (create_buffers(early_trace));
}

int
kdbg_reinit(boolean_t early_trace)
{
        int ret = 0;

        /*
         * Disable trace collecting
         * First make sure we're not in
         * the middle of cutting a trace
         */
        kdbg_set_tracing_enabled(FALSE, KDEBUG_ENABLE_TRACE);

        /*
         * make sure the SLOW_NOLOG is seen
         * by everyone that might be trying
         * to cut a trace..
         */
        IOSleep(100);

        delete_buffers();

        if ((kd_ctrl_page.kdebug_flags & KDBG_MAPINIT) && kd_mapsize && kd_mapptr) {
                kmem_free(kernel_map, (vm_offset_t)kd_mapptr, kd_mapsize);
                kd_ctrl_page.kdebug_flags &= ~KDBG_MAPINIT;
                kd_mapsize = 0;
                kd_mapptr = (kd_threadmap *) 0;
                kd_mapcount = 0;
        }  
        ret = kdbg_bootstrap(early_trace);

        RAW_file_offset = 0;
        RAW_file_written = 0;

        return(ret);
}

void
kdbg_trace_data(struct proc *proc, long *arg_pid)
{
        if (!proc)
                *arg_pid = 0;
        else
                *arg_pid = proc->p_pid;
}


void
kdbg_trace_string(struct proc *proc, long *arg1, long *arg2, long *arg3, long *arg4)
{
        char *dbg_nameptr; 
        int dbg_namelen;
        long dbg_parms[4];

        if (!proc) {
                *arg1 = 0;
                *arg2 = 0;
                *arg3 = 0;
                *arg4 = 0;
                return;
        }
        /*
         * Collect the pathname for tracing
         */
        dbg_nameptr = proc->p_comm;
        dbg_namelen = (int)strlen(proc->p_comm);
        dbg_parms[0]=0L;
        dbg_parms[1]=0L;
        dbg_parms[2]=0L;
        dbg_parms[3]=0L;
  
        if(dbg_namelen > (int)sizeof(dbg_parms))
                dbg_namelen = (int)sizeof(dbg_parms);
    
        strncpy((char *)dbg_parms, dbg_nameptr, dbg_namelen);

        *arg1=dbg_parms[0];
        *arg2=dbg_parms[1];
        *arg3=dbg_parms[2];
        *arg4=dbg_parms[3];
}

static void
kdbg_resolve_map(thread_t th_act, void *opaque)
{
        kd_threadmap *mapptr;
        krt_t *t = (krt_t *)opaque;

        if (t->count < t->maxcount) {
                mapptr = &t->map[t->count];
                mapptr->thread  = (uintptr_t)thread_tid(th_act);

                (void) strlcpy (mapptr->command, t->atts->task_comm,
                                sizeof(t->atts->task_comm));
                /*
                 * Some kernel threads have no associated pid.
                 * We still need to mark the entry as valid.
                 */
                if (t->atts->pid)
                        mapptr->valid = t->atts->pid;
                else
                        mapptr->valid = 1;

                t->count++;
        }
}

/*
 *
 * Writes a cpumap for the given iops_list/cpu_count to the provided buffer.
 *
 * You may provide a buffer and size, or if you set the buffer to NULL, a
 * buffer of sufficient size will be allocated.
 *
 * If you provide a buffer and it is too small, sets cpumap_size to the number
 * of bytes required and returns EINVAL.
 *
 * On success, if you provided a buffer, cpumap_size is set to the number of
 * bytes written. If you did not provide a buffer, cpumap is set to the newly
 * allocated buffer and cpumap_size is set to the number of bytes allocated.
 *
 * NOTE: It may seem redundant to pass both iops and a cpu_count.
 *
 * We may be reporting data from "now", or from the "past".
 *
 * The "now" data would be for something like kdbg_readcurcpumap().
 * The "past" data would be for kdbg_readcpumap().
 *
 * If we do not pass both iops and cpu_count, and iops is NULL, this function
 * will need to read "now" state to get the number of cpus, which would be in
 * error if we were reporting "past" state.
 */

int
kdbg_cpumap_init_internal(kd_iop_t* iops, uint32_t cpu_count, uint8_t** cpumap, uint32_t* cpumap_size)
{
        assert(cpumap);
        assert(cpumap_size);
        assert(cpu_count);
        assert(!iops || iops->cpu_id + 1 == cpu_count);

        uint32_t bytes_needed = sizeof(kd_cpumap_header) + cpu_count * sizeof(kd_cpumap);
        uint32_t bytes_available = *cpumap_size;
        *cpumap_size = bytes_needed;
        
        if (*cpumap == NULL) {
                if (kmem_alloc(kernel_map, (vm_offset_t*)cpumap, (vm_size_t)*cpumap_size) != KERN_SUCCESS) {
                        return ENOMEM;
                }
        } else if (bytes_available < bytes_needed) {
                return EINVAL;
        }

        kd_cpumap_header* header = (kd_cpumap_header*)(uintptr_t)*cpumap;

        header->version_no = RAW_VERSION1;
        header->cpu_count = cpu_count;

        kd_cpumap* cpus = (kd_cpumap*)&header[1];

        int32_t index = cpu_count - 1;
        while (iops) {
                cpus[index].cpu_id = iops->cpu_id;
                cpus[index].flags = KDBG_CPUMAP_IS_IOP;
                bzero(cpus[index].name, sizeof(cpus->name));
                strlcpy(cpus[index].name, iops->callback.iop_name, sizeof(cpus->name));
                
                iops = iops->next;
                index--;
        }
        
        while (index >= 0) {
                cpus[index].cpu_id = index;
                cpus[index].flags = 0;
                bzero(cpus[index].name, sizeof(cpus->name));
                strlcpy(cpus[index].name, "AP", sizeof(cpus->name));

                index--;
        }
        
        return KERN_SUCCESS;
}

void
kdbg_thrmap_init(void)
{
        if (kd_ctrl_page.kdebug_flags & KDBG_MAPINIT)
                return;

        kd_mapptr = kdbg_thrmap_init_internal(0, &kd_mapsize, &kd_mapcount);

        if (kd_mapptr)
                kd_ctrl_page.kdebug_flags |= KDBG_MAPINIT;
}


kd_threadmap* kdbg_thrmap_init_internal(unsigned int count, unsigned int *mapsize, unsigned int *mapcount)
{
        kd_threadmap    *mapptr;
        struct proc     *p;
        struct krt      akrt;
        int             tts_count;    /* number of task-to-string structures */
        struct tts      *tts_mapptr;
        unsigned int    tts_mapsize = 0;
        int             i;
        vm_offset_t     kaddr;

        /*
         * need to use PROC_SCANPROCLIST with proc_iterate
         */
        proc_list_lock();

        /*
         * Calculate the sizes of map buffers
         */
        for (p = allproc.lh_first, *mapcount=0, tts_count=0; p; p = p->p_list.le_next) {
                *mapcount += get_task_numacts((task_t)p->task);
                tts_count++;
        }
        proc_list_unlock();

        /*
         * The proc count could change during buffer allocation,
         * so introduce a small fudge factor to bump up the
         * buffer sizes. This gives new tasks some chance of 
         * making into the tables.  Bump up by 25%.
         */
        *mapcount += *mapcount/4;
        tts_count += tts_count/4;

        *mapsize = *mapcount * sizeof(kd_threadmap);

        if (count && count < *mapcount)
                return (0);

        if ((kmem_alloc(kernel_map, &kaddr, (vm_size_t)*mapsize) == KERN_SUCCESS)) {
                bzero((void *)kaddr, *mapsize);
                mapptr = (kd_threadmap *)kaddr;
        } else
                return (0);

        tts_mapsize = tts_count * sizeof(struct tts);

        if ((kmem_alloc(kernel_map, &kaddr, (vm_size_t)tts_mapsize) == KERN_SUCCESS)) {
                bzero((void *)kaddr, tts_mapsize);
                tts_mapptr = (struct tts *)kaddr;
        } else {
                kmem_free(kernel_map, (vm_offset_t)mapptr, *mapsize);

                return (0);
        }
        /* 
         * We need to save the procs command string
         * and take a reference for each task associated
         * with a valid process
         */

        proc_list_lock();

        /*
         * should use proc_iterate
         */
        for (p = allproc.lh_first, i=0; p && i < tts_count; p = p->p_list.le_next) {
                if (p->p_lflag & P_LEXIT)
                        continue;

                if (p->task) {
                        task_reference(p->task);
                        tts_mapptr[i].task = p->task;
                        tts_mapptr[i].pid  = p->p_pid;
                        (void)strlcpy(tts_mapptr[i].task_comm, p->p_comm, sizeof(tts_mapptr[i].task_comm));
                        i++;
                }
        }
        tts_count = i;

        proc_list_unlock();

        /*
         * Initialize thread map data
         */
        akrt.map = mapptr;
        akrt.count = 0;
        akrt.maxcount = *mapcount;
            
        for (i = 0; i < tts_count; i++) {
                akrt.atts = &tts_mapptr[i];
                task_act_iterate_wth_args(tts_mapptr[i].task, kdbg_resolve_map, &akrt);
                task_deallocate((task_t) tts_mapptr[i].task);
        }
        kmem_free(kernel_map, (vm_offset_t)tts_mapptr, tts_mapsize);

        *mapcount = akrt.count;

        return (mapptr);
}

static void
kdbg_clear(void)
{
        /*
         * Clean up the trace buffer
         * First make sure we're not in
         * the middle of cutting a trace
         */
        kdbg_set_tracing_enabled(FALSE, KDEBUG_ENABLE_TRACE);

        /*
         * make sure the SLOW_NOLOG is seen
         * by everyone that might be trying
         * to cut a trace..
         */
        IOSleep(100);

        global_state_pid = -1;
        kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
        kd_ctrl_page.kdebug_flags &= ~(KDBG_NOWRAP | KDBG_RANGECHECK | KDBG_VALCHECK);
        kd_ctrl_page.kdebug_flags &= ~(KDBG_PIDCHECK | KDBG_PIDEXCLUDE);
        
        kdbg_disable_typefilter();

        delete_buffers();
        nkdbufs = 0;

        /* Clean up the thread map buffer */
        kd_ctrl_page.kdebug_flags &= ~KDBG_MAPINIT;
        if (kd_mapptr) {
                kmem_free(kernel_map, (vm_offset_t)kd_mapptr, kd_mapsize);
                kd_mapptr = (kd_threadmap *) 0;
        }
        kd_mapsize = 0;
        kd_mapcount = 0;

        RAW_file_offset = 0;
        RAW_file_written = 0;
}

int
kdbg_setpid(kd_regtype *kdr)
{
        pid_t pid;
        int flag, ret=0;
        struct proc *p;

        pid = (pid_t)kdr->value1;
        flag = (int)kdr->value2;

        if (pid > 0) {
                if ((p = proc_find(pid)) == NULL)
                        ret = ESRCH;
                else {
                        if (flag == 1) {
                                /*
                                 * turn on pid check for this and all pids
                                 */
                                kd_ctrl_page.kdebug_flags |= KDBG_PIDCHECK;
                                kd_ctrl_page.kdebug_flags &= ~KDBG_PIDEXCLUDE;
                                kdbg_set_flags(SLOW_CHECKS, 0, TRUE);

                                p->p_kdebug = 1;
                        } else {
                                /*
                                 * turn off pid check for this pid value
                                 * Don't turn off all pid checking though
                                 *
                                 * kd_ctrl_page.kdebug_flags &= ~KDBG_PIDCHECK;
                                 */   
                                p->p_kdebug = 0;
                        }
                        proc_rele(p);
                }
        }
        else
                ret = EINVAL;

        return(ret);
}

/* This is for pid exclusion in the trace buffer */
int
kdbg_setpidex(kd_regtype *kdr)
{
        pid_t pid;
        int flag, ret=0;
        struct proc *p;

        pid = (pid_t)kdr->value1;
        flag = (int)kdr->value2;

        if (pid > 0) {
                if ((p = proc_find(pid)) == NULL)
                        ret = ESRCH;
                else {
                        if (flag == 1) {
                                /*
                                 * turn on pid exclusion
                                 */
                                kd_ctrl_page.kdebug_flags |= KDBG_PIDEXCLUDE;
                                kd_ctrl_page.kdebug_flags &= ~KDBG_PIDCHECK;
                                kdbg_set_flags(SLOW_CHECKS, 0, TRUE);

                                p->p_kdebug = 1;
                        }
                        else {
                                /*
                                 * turn off pid exclusion for this pid value
                                 * Don't turn off all pid exclusion though
                                 *
                                 * kd_ctrl_page.kdebug_flags &= ~KDBG_PIDEXCLUDE;
                                 */   
                                p->p_kdebug = 0;
                        }
                        proc_rele(p);
                }
        } else
                ret = EINVAL;

        return(ret);
}


/*
 * This is for setting a maximum decrementer value
 */
int
kdbg_setrtcdec(kd_regtype *kdr)
{
        int ret = 0;
        natural_t decval;

        decval = (natural_t)kdr->value1;

        if (decval && decval < KDBG_MINRTCDEC)
                ret = EINVAL;
        else
                ret = ENOTSUP;

        return(ret);
}

int
kdbg_enable_typefilter(void)
{
        if (kd_ctrl_page.kdebug_flags & KDBG_TYPEFILTER_CHECK) {
                /* free the old filter */
                kdbg_disable_typefilter();
        }
        
        if (kmem_alloc(kernel_map, (vm_offset_t *)&type_filter_bitmap, KDBG_TYPEFILTER_BITMAP_SIZE) != KERN_SUCCESS) {
                return ENOSPC;
        }
        
        bzero(type_filter_bitmap, KDBG_TYPEFILTER_BITMAP_SIZE);

        /* Turn off range and value checks */
        kd_ctrl_page.kdebug_flags &= ~(KDBG_RANGECHECK | KDBG_VALCHECK);
        
        /* Enable filter checking */
        kd_ctrl_page.kdebug_flags |= KDBG_TYPEFILTER_CHECK;
        kdbg_set_flags(SLOW_CHECKS, 0, TRUE);
        return 0;
}

int
kdbg_disable_typefilter(void)
{
        /*  Disable filter checking */  
        kd_ctrl_page.kdebug_flags &= ~KDBG_TYPEFILTER_CHECK;
        
        /*  Turn off slow checks unless pid checks are using them */
        if ( (kd_ctrl_page.kdebug_flags & (KDBG_PIDCHECK | KDBG_PIDEXCLUDE)) )
                kdbg_set_flags(SLOW_CHECKS, 0, TRUE);
        else
                kdbg_set_flags(SLOW_CHECKS, 0, FALSE);
        
        if(type_filter_bitmap == NULL)
                return 0;

        vm_offset_t old_bitmap = (vm_offset_t)type_filter_bitmap;
        type_filter_bitmap = NULL;

        kmem_free(kernel_map, old_bitmap, KDBG_TYPEFILTER_BITMAP_SIZE);
        return 0;
}

int
kdbg_setreg(kd_regtype * kdr)
{
        int ret=0;
        unsigned int val_1, val_2, val;
        switch (kdr->type) {
        
        case KDBG_CLASSTYPE :
                val_1 = (kdr->value1 & 0xff);
                val_2 = (kdr->value2 & 0xff);
                kdlog_beg = (val_1<<24);
                kdlog_end = (val_2<<24);
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
                kd_ctrl_page.kdebug_flags &= ~KDBG_VALCHECK;       /* Turn off specific value check  */
                kd_ctrl_page.kdebug_flags |= (KDBG_RANGECHECK | KDBG_CLASSTYPE);
                kdbg_set_flags(SLOW_CHECKS, 0, TRUE);
                break;
        case KDBG_SUBCLSTYPE :
                val_1 = (kdr->value1 & 0xff);
                val_2 = (kdr->value2 & 0xff);
                val = val_2 + 1;
                kdlog_beg = ((val_1<<24) | (val_2 << 16));
                kdlog_end = ((val_1<<24) | (val << 16));
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
                kd_ctrl_page.kdebug_flags &= ~KDBG_VALCHECK;       /* Turn off specific value check  */
                kd_ctrl_page.kdebug_flags |= (KDBG_RANGECHECK | KDBG_SUBCLSTYPE);
                kdbg_set_flags(SLOW_CHECKS, 0, TRUE);
                break;
        case KDBG_RANGETYPE :
                kdlog_beg = (kdr->value1);
                kdlog_end = (kdr->value2);
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
                kd_ctrl_page.kdebug_flags &= ~KDBG_VALCHECK;       /* Turn off specific value check  */
                kd_ctrl_page.kdebug_flags |= (KDBG_RANGECHECK | KDBG_RANGETYPE);
                kdbg_set_flags(SLOW_CHECKS, 0, TRUE);
                break;
        case KDBG_VALCHECK:
                kdlog_value1 = (kdr->value1);
                kdlog_value2 = (kdr->value2);
                kdlog_value3 = (kdr->value3);
                kdlog_value4 = (kdr->value4);
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
                kd_ctrl_page.kdebug_flags &= ~KDBG_RANGECHECK;    /* Turn off range check */
                kd_ctrl_page.kdebug_flags |= KDBG_VALCHECK;       /* Turn on specific value check  */
                kdbg_set_flags(SLOW_CHECKS, 0, TRUE);
                break;
        case KDBG_TYPENONE :
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;

                if ( (kd_ctrl_page.kdebug_flags & (KDBG_RANGECHECK | KDBG_VALCHECK   | 
                                                   KDBG_PIDCHECK   | KDBG_PIDEXCLUDE | 
                                                   KDBG_TYPEFILTER_CHECK)) )
                        kdbg_set_flags(SLOW_CHECKS, 0, TRUE);
                else
                        kdbg_set_flags(SLOW_CHECKS, 0, FALSE);

                kdlog_beg = 0;
                kdlog_end = 0;
                break;
        default :
                ret = EINVAL;
                break;
        }
        return(ret);
}

int
kdbg_getreg(__unused kd_regtype * kdr)
{
#if 0   
        int i,j, ret=0;
        unsigned int val_1, val_2, val;

        switch (kdr->type) {
        case KDBG_CLASSTYPE :
                val_1 = (kdr->value1 & 0xff);
                val_2 = val_1 + 1;
                kdlog_beg = (val_1<<24);
                kdlog_end = (val_2<<24);
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
                kd_ctrl_page.kdebug_flags |= (KDBG_RANGECHECK | KDBG_CLASSTYPE);
                break;
        case KDBG_SUBCLSTYPE :
                val_1 = (kdr->value1 & 0xff);
                val_2 = (kdr->value2 & 0xff);
                val = val_2 + 1;
                kdlog_beg = ((val_1<<24) | (val_2 << 16));
                kdlog_end = ((val_1<<24) | (val << 16));
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
                kd_ctrl_page.kdebug_flags |= (KDBG_RANGECHECK | KDBG_SUBCLSTYPE);
                break;
        case KDBG_RANGETYPE :
                kdlog_beg = (kdr->value1);
                kdlog_end = (kdr->value2);
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
                kd_ctrl_page.kdebug_flags |= (KDBG_RANGECHECK | KDBG_RANGETYPE);
                break;
        case KDBG_TYPENONE :
                kd_ctrl_page.kdebug_flags &= (unsigned int)~KDBG_CKTYPES;
                kdlog_beg = 0;
                kdlog_end = 0;
                break;
        default :
                ret = EINVAL;
                break;
        }
#endif /* 0 */
        return(EINVAL);
}

int
kdbg_readcpumap(user_addr_t user_cpumap, size_t *user_cpumap_size)
{
        uint8_t* cpumap = NULL;
        uint32_t cpumap_size = 0;
        int ret = KERN_SUCCESS;

        if (kd_ctrl_page.kdebug_flags & KDBG_BUFINIT) {
                if (kdbg_cpumap_init_internal(kd_ctrl_page.kdebug_iops, kd_ctrl_page.kdebug_cpus, &cpumap, &cpumap_size) == KERN_SUCCESS) {
                        if (user_cpumap) {
                                size_t bytes_to_copy = (*user_cpumap_size >= cpumap_size) ? cpumap_size : *user_cpumap_size;
                                if (copyout(cpumap, user_cpumap, (size_t)bytes_to_copy)) {
                                        ret = EFAULT;
                                }
                        }
                        *user_cpumap_size = cpumap_size;
                        kmem_free(kernel_map, (vm_offset_t)cpumap, cpumap_size);
                } else
                        ret = EINVAL;
        } else
                ret = EINVAL;

        return (ret);
}

int
kdbg_readcurthrmap(user_addr_t buffer, size_t *bufsize)
{
        kd_threadmap *mapptr;
        unsigned int mapsize;
        unsigned int mapcount;
        unsigned int count = 0;
        int ret = 0;

        count = *bufsize/sizeof(kd_threadmap);
        *bufsize = 0;

        if ( (mapptr = kdbg_thrmap_init_internal(count, &mapsize, &mapcount)) ) {
                if (copyout(mapptr, buffer, mapcount * sizeof(kd_threadmap)))
                        ret = EFAULT;
                else
                        *bufsize = (mapcount * sizeof(kd_threadmap));

                kmem_free(kernel_map, (vm_offset_t)mapptr, mapsize);
        } else
                ret = EINVAL;

        return (ret);
}

int
kdbg_readthrmap(user_addr_t buffer, size_t *number, vnode_t vp, vfs_context_t ctx)
{
        int avail = *number;
        int ret = 0;
        uint32_t count = 0;
        unsigned int mapsize;

        count = avail/sizeof (kd_threadmap);

        mapsize = kd_mapcount * sizeof(kd_threadmap);

        if (count && (count <= kd_mapcount))
        {
                if ((kd_ctrl_page.kdebug_flags & KDBG_MAPINIT) && kd_mapsize && kd_mapptr)
                {
                        if (*number < mapsize)
                                ret = EINVAL;
                        else
                        {
                                if (vp)
                                {
                                        RAW_header      header;
                                        clock_sec_t     secs;
                                        clock_usec_t    usecs;
                                        char    *pad_buf;
                                        uint32_t pad_size;
                                        uint32_t extra_thread_count = 0;
                                        uint32_t cpumap_size;
                                        
                                        /*
                                         * To write a RAW_VERSION1+ file, we
                                         * must embed a cpumap in the "padding"
                                         * used to page align the events folloing
                                         * the threadmap. If the threadmap happens
                                         * to not require enough padding, we
                                         * artificially increase its footprint
                                         * until it needs enough padding.
                                         */

                                        pad_size = PAGE_SIZE - ((sizeof(RAW_header) + (count * sizeof(kd_threadmap))) & PAGE_MASK_64);
                                        cpumap_size = sizeof(kd_cpumap_header) + kd_ctrl_page.kdebug_cpus * sizeof(kd_cpumap);

                                        if (cpumap_size > pad_size) {
                                                /* Force an overflow onto the next page, we get a full page of padding */
                                                extra_thread_count = (pad_size / sizeof(kd_threadmap)) + 1;
                                        }

                                        header.version_no = RAW_VERSION1;
                                        header.thread_count = count + extra_thread_count;

                                        clock_get_calendar_microtime(&secs, &usecs);
                                        header.TOD_secs = secs;
                                        header.TOD_usecs = usecs;

                                        ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)&header, sizeof(RAW_header), RAW_file_offset,
                                                      UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, vfs_context_ucred(ctx), (int *) 0, vfs_context_proc(ctx));
                                        if (ret)
                                                goto write_error;
                                        RAW_file_offset += sizeof(RAW_header);

                                        ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)kd_mapptr, mapsize, RAW_file_offset,
                                                      UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, vfs_context_ucred(ctx), (int *) 0, vfs_context_proc(ctx));
                                        if (ret)
                                                goto write_error;
                                        RAW_file_offset += mapsize;

                                        if (extra_thread_count) {
                                                pad_size = extra_thread_count * sizeof(kd_threadmap);
                                                pad_buf = (char *)kalloc(pad_size);
                                                memset(pad_buf, 0, pad_size);

                                                ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)pad_buf, pad_size, RAW_file_offset,
                                                              UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, vfs_context_ucred(ctx), (int *) 0, vfs_context_proc(ctx));
                                                kfree(pad_buf, pad_size);

                                                if (ret)
                                                        goto write_error;
                                                RAW_file_offset += pad_size;

                                        }
                                        
                                        pad_size = PAGE_SIZE - (RAW_file_offset & PAGE_MASK_64);
                                        if (pad_size) {
                                                pad_buf = (char *)kalloc(pad_size);
                                                memset(pad_buf, 0, pad_size);

                                                /*
                                                 * embed a cpumap in the padding bytes.
                                                 * older code will skip this.
                                                 * newer code will know how to read it.
                                                 */
                                                uint32_t temp = pad_size;
                                                if (kdbg_cpumap_init_internal(kd_ctrl_page.kdebug_iops, kd_ctrl_page.kdebug_cpus, (uint8_t**)&pad_buf, &temp) != KERN_SUCCESS) {
                                                        memset(pad_buf, 0, pad_size);
                                                }

                                                ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)pad_buf, pad_size, RAW_file_offset,
                                                              UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, vfs_context_ucred(ctx), (int *) 0, vfs_context_proc(ctx));
                                                kfree(pad_buf, pad_size);

                                                if (ret)
                                                        goto write_error;
                                                RAW_file_offset += pad_size;
                                        }
                                        RAW_file_written += sizeof(RAW_header) + mapsize + pad_size;

                                } else {
                                        if (copyout(kd_mapptr, buffer, mapsize))
                                                ret = EINVAL;
                                }
                        }
                }
                else
                        ret = EINVAL;
        }
        else
                ret = EINVAL;

        if (ret && vp)
        {
                count = 0;

                vn_rdwr(UIO_WRITE, vp, (caddr_t)&count, sizeof(uint32_t), RAW_file_offset,
                        UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, vfs_context_ucred(ctx), (int *) 0, vfs_context_proc(ctx));
                RAW_file_offset += sizeof(uint32_t);
                RAW_file_written += sizeof(uint32_t);
        }
write_error:
        if ((kd_ctrl_page.kdebug_flags & KDBG_MAPINIT) && kd_mapsize && kd_mapptr)
        {
                kmem_free(kernel_map, (vm_offset_t)kd_mapptr, kd_mapsize);
                kd_ctrl_page.kdebug_flags &= ~KDBG_MAPINIT;
                kd_mapsize = 0;
                kd_mapptr = (kd_threadmap *) 0;
                kd_mapcount = 0;
        }  
        return(ret);
}


static int
kdbg_set_nkdbufs(unsigned int value)
{
        /*
         * We allow a maximum buffer size of 50% of either ram or max mapped address, whichever is smaller
         * 'value' is the desired number of trace entries
         */
        unsigned int max_entries = (sane_size/2) / sizeof(kd_buf);

        if (value <= max_entries)
                return (value);
        else
                return (max_entries);
}


static int
kdbg_enable_bg_trace(void)
{
        int ret = 0;

        if (kdlog_bg_trace == TRUE && kdlog_bg_trace_running == FALSE && n_storage_buffers == 0) {
                nkdbufs = bg_nkdbufs;
                ret = kdbg_reinit(FALSE);
                if (0 == ret) {
                        kdbg_set_tracing_enabled(TRUE, KDEBUG_ENABLE_TRACE);
                        kdlog_bg_trace_running = TRUE;
                }
        }
        return ret;
}

static void
kdbg_disable_bg_trace(void)
{
        if (kdlog_bg_trace_running == TRUE) {
                kdlog_bg_trace_running = FALSE;
                kdbg_clear();           
        }
}



/*
 * This function is provided for the CHUD toolkit only.
 *    int val:
 *        zero disables kdebug_chudhook function call
 *        non-zero enables kdebug_chudhook function call
 *    char *fn:
 *        address of the enabled kdebug_chudhook function
*/

void
kdbg_control_chud(int val, void *fn)
{
        kdbg_lock_init();
    
        if (val) {
                /* enable chudhook */
                kdebug_chudhook = fn;
                kdbg_set_flags(SLOW_CHUD, KDEBUG_ENABLE_CHUD, TRUE);
        }
        else {
                /* disable chudhook */
                kdbg_set_flags(SLOW_CHUD, KDEBUG_ENABLE_CHUD, FALSE);
                kdebug_chudhook = 0;
        }
}

        
int
kdbg_control(int *name, u_int namelen, user_addr_t where, size_t *sizep)
{
        int ret = 0;
        size_t size = *sizep;
        unsigned int value = 0;
        kd_regtype kd_Reg;
        kbufinfo_t kd_bufinfo;
        pid_t curpid;
        proc_t p, curproc;

        if (name[0] == KERN_KDGETENTROPY ||
                name[0] == KERN_KDWRITETR ||
                name[0] == KERN_KDWRITEMAP ||
                name[0] == KERN_KDEFLAGS ||
                name[0] == KERN_KDDFLAGS ||
                name[0] == KERN_KDENABLE ||
                name[0] == KERN_KDENABLE_BG_TRACE ||
                name[0] == KERN_KDSETBUF) {
                
                if ( namelen < 2 )
                        return(EINVAL);
                value = name[1];
        }
        
        kdbg_lock_init();

        if ( !(kd_ctrl_page.kdebug_flags & KDBG_LOCKINIT))
                return(ENOSPC);

        lck_mtx_lock(kd_trace_mtx_sysctl);

        switch(name[0]) {
                case KERN_KDGETBUF:
                        /*
                         * Does not alter the global_state_pid
                         * This is a passive request.
                         */
                        if (size < sizeof(kd_bufinfo.nkdbufs)) {
                                /*
                                 * There is not enough room to return even
                                 * the first element of the info structure.
                                 */
                                ret = EINVAL;
                                goto out;
                        }
                        kd_bufinfo.nkdbufs = nkdbufs;
                        kd_bufinfo.nkdthreads = kd_mapcount;
                        
                        if ( (kd_ctrl_page.kdebug_slowcheck & SLOW_NOLOG) )
                                kd_bufinfo.nolog = 1;
                        else
                                kd_bufinfo.nolog = 0;
                        
                        kd_bufinfo.flags = kd_ctrl_page.kdebug_flags;
#if defined(__LP64__)
                        kd_bufinfo.flags |= KDBG_LP64;
#endif
                        kd_bufinfo.bufid = global_state_pid;
                        
                        if (size >= sizeof(kd_bufinfo)) {
                                /*
                                 * Provide all the info we have
                                 */
                                if (copyout(&kd_bufinfo, where, sizeof(kd_bufinfo)))
                                        ret = EINVAL;
                        } else {
                                /*
                                 * For backwards compatibility, only provide
                                 * as much info as there is room for.
                                 */
                                if (copyout(&kd_bufinfo, where, size))
                                        ret = EINVAL;
                        }
                        goto out;
                        
                case KERN_KDGETENTROPY: {
                        /* Obsolescent - just fake with a random buffer */
                        char    *buffer = (char *) kalloc(size);
                        read_frandom((void *) buffer, size);
                        ret = copyout(buffer, where, size);
                        kfree(buffer, size);
                        goto out;
                }
                        
                case KERN_KDENABLE_BG_TRACE:
                        bg_nkdbufs = kdbg_set_nkdbufs(value);
                        kdlog_bg_trace = TRUE;
                        ret = kdbg_enable_bg_trace();
                        goto out;
                        
                case KERN_KDDISABLE_BG_TRACE:
                        kdlog_bg_trace = FALSE;
                        kdbg_disable_bg_trace();
                        goto out;
        }
        
        if ((curproc = current_proc()) != NULL)
                curpid = curproc->p_pid;
        else {
                ret = ESRCH;
                goto out;
        }
        if (global_state_pid == -1)
                global_state_pid = curpid;
        else if (global_state_pid != curpid) {
                if ((p = proc_find(global_state_pid)) == NULL) {
                        /*
                         * The global pid no longer exists
                         */
                        global_state_pid = curpid;
                } else {
                        /*
                         * The global pid exists, deny this request
                         */
                        proc_rele(p);

                        ret = EBUSY;
                        goto out;
                }
        }

        switch(name[0]) {
                case KERN_KDEFLAGS:
                        kdbg_disable_bg_trace();

                        value &= KDBG_USERFLAGS;
                        kd_ctrl_page.kdebug_flags |= value;
                        break;
                case KERN_KDDFLAGS:
                        kdbg_disable_bg_trace();

                        value &= KDBG_USERFLAGS;
                        kd_ctrl_page.kdebug_flags &= ~value;
                        break;
                case KERN_KDENABLE:
                        /*
                         * Enable tracing mechanism.  Two types:
                         * KDEBUG_TRACE is the standard one,
                         * and KDEBUG_PPT which is a carefully
                         * chosen subset to avoid performance impact.
                         */
                        if (value) {
                                /*
                                 * enable only if buffer is initialized
                                 */
                                if (!(kd_ctrl_page.kdebug_flags & KDBG_BUFINIT) || 
                                    !(value == KDEBUG_ENABLE_TRACE || value == KDEBUG_ENABLE_PPT)) {
                                        ret = EINVAL;
                                        break;
                                }
                                kdbg_thrmap_init();

                                kdbg_set_tracing_enabled(TRUE, value);
                        }
                        else
                        {
                                kdbg_set_tracing_enabled(FALSE, 0);
                        }
                        break;
                case KERN_KDSETBUF:
                        kdbg_disable_bg_trace();

                        nkdbufs = kdbg_set_nkdbufs(value);
                        break;
                case KERN_KDSETUP:
                        kdbg_disable_bg_trace();

                        ret = kdbg_reinit(FALSE);
                        break;
                case KERN_KDREMOVE:
                        kdbg_clear();
                        ret = kdbg_enable_bg_trace();
                        break;
                case KERN_KDSETREG:
                        if(size < sizeof(kd_regtype)) {
                                ret = EINVAL;
                                break;
                        }
                        if (copyin(where, &kd_Reg, sizeof(kd_regtype))) {
                                ret = EINVAL;
                                break;
                        }
                        kdbg_disable_bg_trace();

                        ret = kdbg_setreg(&kd_Reg);
                        break;
                case KERN_KDGETREG:
                        if (size < sizeof(kd_regtype)) {
                                ret = EINVAL;
                                break;
                        }
                        ret = kdbg_getreg(&kd_Reg);
                        if (copyout(&kd_Reg, where, sizeof(kd_regtype))) {
                                ret = EINVAL;
                        }
                        kdbg_disable_bg_trace();

                        break;
                case KERN_KDREADTR:
                        ret = kdbg_read(where, sizep, NULL, NULL);
                        break;
                case KERN_KDWRITETR:
                case KERN_KDWRITEMAP:
                {
                        struct  vfs_context context;
                        struct  fileproc *fp;
                        size_t  number;
                        vnode_t vp;
                        int     fd;

                        kdbg_disable_bg_trace();

                        if (name[0] == KERN_KDWRITETR) {
                                int s;
                                int wait_result = THREAD_AWAKENED;
                                u_int64_t abstime;
                                u_int64_t ns;

                                if (*sizep) {
                                        ns = ((u_int64_t)*sizep) * (u_int64_t)(1000 * 1000);
                                        nanoseconds_to_absolutetime(ns,  &abstime );
                                        clock_absolutetime_interval_to_deadline( abstime, &abstime );
                                } else
                                        abstime = 0;

                                s = ml_set_interrupts_enabled(FALSE);
                                lck_spin_lock(kdw_spin_lock);

                                while (wait_result == THREAD_AWAKENED && kd_ctrl_page.kds_inuse_count < n_storage_threshold) {

                                        kds_waiter = 1;

                                        if (abstime)
                                                wait_result = lck_spin_sleep_deadline(kdw_spin_lock, 0, &kds_waiter, THREAD_ABORTSAFE, abstime);
                                        else
                                                wait_result = lck_spin_sleep(kdw_spin_lock, 0, &kds_waiter, THREAD_ABORTSAFE);
                                        
                                        kds_waiter = 0;
                                }
                                lck_spin_unlock(kdw_spin_lock);
                                ml_set_interrupts_enabled(s);
                        }
                        p = current_proc();
                        fd = value;

                        proc_fdlock(p);
                        if ( (ret = fp_lookup(p, fd, &fp, 1)) ) {
                                proc_fdunlock(p);
                                break;
                        }
                        context.vc_thread = current_thread();
                        context.vc_ucred = fp->f_fglob->fg_cred;

                        if (FILEGLOB_DTYPE(fp->f_fglob) != DTYPE_VNODE) {
                                fp_drop(p, fd, fp, 1);
                                proc_fdunlock(p);

                                ret = EBADF;
                                break;
                        }
                        vp = (struct vnode *)fp->f_fglob->fg_data;
                        proc_fdunlock(p);

                        if ((ret = vnode_getwithref(vp)) == 0) {
                                RAW_file_offset = fp->f_fglob->fg_offset;
                                if (name[0] == KERN_KDWRITETR) {
                                        number = nkdbufs * sizeof(kd_buf);

                                        KERNEL_DEBUG_CONSTANT(TRACE_WRITING_EVENTS | DBG_FUNC_START, 0, 0, 0, 0, 0);
                                        ret = kdbg_read(0, &number, vp, &context);
                                        KERNEL_DEBUG_CONSTANT(TRACE_WRITING_EVENTS | DBG_FUNC_END, number, 0, 0, 0, 0);

                                        *sizep = number;
                                } else {
                                        number = kd_mapcount * sizeof(kd_threadmap);
                                        kdbg_readthrmap(0, &number, vp, &context);
                                }
                                fp->f_fglob->fg_offset = RAW_file_offset;
                                vnode_put(vp);
                        }
                        fp_drop(p, fd, fp, 0);

                        break;
                }
                case KERN_KDBUFWAIT:
                {
                        /* WRITETR lite -- just block until there's data */
                        int s;
                        int wait_result = THREAD_AWAKENED;
                        u_int64_t abstime;
                        u_int64_t ns;
                        size_t  number = 0;

                        kdbg_disable_bg_trace();


                        if (*sizep) {
                                ns = ((u_int64_t)*sizep) * (u_int64_t)(1000 * 1000);
                                nanoseconds_to_absolutetime(ns,  &abstime );
                                clock_absolutetime_interval_to_deadline( abstime, &abstime );
                        } else
                                abstime = 0;

                        s = ml_set_interrupts_enabled(FALSE);
                        if( !s )
                                panic("trying to wait with interrupts off");
                        lck_spin_lock(kdw_spin_lock);

                        /* drop the mutex so don't exclude others from
                         * accessing trace
                         */
                        lck_mtx_unlock(kd_trace_mtx_sysctl);

                        while (wait_result == THREAD_AWAKENED &&
                                kd_ctrl_page.kds_inuse_count < n_storage_threshold) {

                                kds_waiter = 1;

                                if (abstime)
                                        wait_result = lck_spin_sleep_deadline(kdw_spin_lock, 0, &kds_waiter, THREAD_ABORTSAFE, abstime);
                                else
                                        wait_result = lck_spin_sleep(kdw_spin_lock, 0, &kds_waiter, THREAD_ABORTSAFE);
                                
                                kds_waiter = 0;
                        }

                        /* check the count under the spinlock */
                        number = (kd_ctrl_page.kds_inuse_count >= n_storage_threshold);

                        lck_spin_unlock(kdw_spin_lock);
                        ml_set_interrupts_enabled(s);

                        /* pick the mutex back up again */
                        lck_mtx_lock(kd_trace_mtx_sysctl);

                        /* write out whether we've exceeded the threshold */
                        *sizep = number;
                        break;
                }
                case KERN_KDPIDTR:
                        if (size < sizeof(kd_regtype)) {
                                ret = EINVAL;
                                break;
                        }
                        if (copyin(where, &kd_Reg, sizeof(kd_regtype))) {
                                ret = EINVAL;
                                break;
                        }
                        kdbg_disable_bg_trace();

                        ret = kdbg_setpid(&kd_Reg);
                        break;
                case KERN_KDPIDEX:
                        if (size < sizeof(kd_regtype)) {
                                ret = EINVAL;
                                break;
                        }
                        if (copyin(where, &kd_Reg, sizeof(kd_regtype))) {
                                ret = EINVAL;
                                break;
                        }
                        kdbg_disable_bg_trace();

                        ret = kdbg_setpidex(&kd_Reg);
                        break;
                case KERN_KDCPUMAP:
                        ret = kdbg_readcpumap(where, sizep);
                        break;
                case KERN_KDTHRMAP:
                        ret = kdbg_readthrmap(where, sizep, NULL, NULL);
                        break;
                case KERN_KDREADCURTHRMAP:
                        ret = kdbg_readcurthrmap(where, sizep);
                        break;
                case KERN_KDSETRTCDEC:
                        if (size < sizeof(kd_regtype)) {
                                ret = EINVAL;
                                break;
                        }
                        if (copyin(where, &kd_Reg, sizeof(kd_regtype))) {
                                ret = EINVAL;
                                break;
                        }
                        kdbg_disable_bg_trace();

                        ret = kdbg_setrtcdec(&kd_Reg);
                        break;
                case KERN_KDSET_TYPEFILTER:
                        kdbg_disable_bg_trace();

                        if ((kd_ctrl_page.kdebug_flags & KDBG_TYPEFILTER_CHECK) == 0){
                                if ((ret = kdbg_enable_typefilter()))
                                        break;
                        }

                        if (size != KDBG_TYPEFILTER_BITMAP_SIZE) {
                                ret = EINVAL;
                                break;
                        }

                        if (copyin(where, type_filter_bitmap, KDBG_TYPEFILTER_BITMAP_SIZE)) {
                                ret = EINVAL;
                                break;
                        }
                        kdbg_iop_list_callback(kd_ctrl_page.kdebug_iops, KD_CALLBACK_TYPEFILTER_CHANGED, type_filter_bitmap);
                        break;
                default:
                        ret = EINVAL;
        }
out:
        lck_mtx_unlock(kd_trace_mtx_sysctl);

        return(ret);
}


/*
 * This code can run for the most part concurrently with kernel_debug_internal()...
 * 'release_storage_unit' will take the kds_spin_lock which may cause us to briefly
 * synchronize with the recording side of this puzzle... otherwise, we are able to
 * move through the lists w/o use of any locks
 */
int
kdbg_read(user_addr_t buffer, size_t *number, vnode_t vp, vfs_context_t ctx)
{
        unsigned int count;
        unsigned int cpu, min_cpu;
        uint64_t  mintime, t, barrier = 0;
        int error = 0;
        kd_buf *tempbuf;
        uint32_t rcursor;
        kd_buf lostevent;
        union kds_ptr kdsp;
        struct kd_storage *kdsp_actual;
        struct kd_bufinfo *kdbp;
        struct kd_bufinfo *min_kdbp;
        uint32_t tempbuf_count;
        uint32_t tempbuf_number;
        uint32_t old_kdebug_flags;
        uint32_t old_kdebug_slowcheck;
        boolean_t lostevents = FALSE;
        boolean_t out_of_events = FALSE;

        count = *number/sizeof(kd_buf);
        *number = 0;

        if (count == 0 || !(kd_ctrl_page.kdebug_flags & KDBG_BUFINIT) || kdcopybuf == 0)
                return EINVAL;

        memset(&lostevent, 0, sizeof(lostevent));
        lostevent.debugid = TRACE_LOST_EVENTS;

        /* Capture timestamp. Only sort events that have occured before the timestamp.
         * Since the iop is being flushed here, its possible that events occur on the AP
         * while running live tracing. If we are disabled, no new events should 
         * occur on the AP.
        */
        
        if (kd_ctrl_page.enabled)
        {
                // timestamp is non-zero value
                barrier = mach_absolute_time() & KDBG_TIMESTAMP_MASK;
        }
        
        // Request each IOP to provide us with up to date entries before merging buffers together.
        kdbg_iop_list_callback(kd_ctrl_page.kdebug_iops, KD_CALLBACK_SYNC_FLUSH, NULL);

        /*
         * because we hold kd_trace_mtx_sysctl, no other control threads can 
         * be playing with kdebug_flags... the code that cuts new events could
         * be running, but it grabs kds_spin_lock if it needs to acquire a new
         * storage chunk which is where it examines kdebug_flags... it its adding
         * to the same chunk we're reading from, no problem... 
         */

        disable_wrap(&old_kdebug_slowcheck, &old_kdebug_flags);

        if (count > nkdbufs)
                count = nkdbufs;

        if ((tempbuf_count = count) > KDCOPYBUF_COUNT)
                tempbuf_count = KDCOPYBUF_COUNT;

        while (count) {
                tempbuf = kdcopybuf;
                tempbuf_number = 0;

                // While space
                while (tempbuf_count) {
                        mintime = 0xffffffffffffffffULL;
                        min_kdbp = NULL;
                        min_cpu = 0;

                        // Check all CPUs
                        for (cpu = 0, kdbp = &kdbip[0]; cpu < kd_ctrl_page.kdebug_cpus; cpu++, kdbp++) {

                                // Find one with raw data
                                if ((kdsp = kdbp->kd_list_head).raw == KDS_PTR_NULL)
                                        continue;
                                /* Debugging aid: maintain a copy of the "kdsp"
                                 * index.
                                 */
                                volatile union kds_ptr kdsp_shadow;

                                kdsp_shadow = kdsp;

                                // Get from cpu data to buffer header to buffer
                                kdsp_actual = POINTER_FROM_KDS_PTR(kdsp);

                                volatile struct kd_storage *kdsp_actual_shadow;

                                kdsp_actual_shadow = kdsp_actual;

                                // See if there are actual data left in this buffer
                                rcursor = kdsp_actual->kds_readlast;

                                if (rcursor == kdsp_actual->kds_bufindx)
                                        continue;

                                t = kdbg_get_timestamp(&kdsp_actual->kds_records[rcursor]);

                                if ((t > barrier) && (barrier > 0)) {
                                        /* 
                                         * Need to wait to flush iop again before we 
                                         * sort any more data from the buffers
                                        */
                                        out_of_events = TRUE;
                                        break;
                                }       
                                if (t < kdsp_actual->kds_timestamp) {
                                        /*
                                         * indicates we've not yet completed filling
                                         * in this event...
                                         * this should only occur when we're looking
                                         * at the buf that the record head is utilizing
                                         * we'll pick these events up on the next
                                         * call to kdbg_read
                                         * we bail at this point so that we don't
                                         * get an out-of-order timestream by continuing
                                         * to read events from the other CPUs' timestream(s)
                                         */
                                        out_of_events = TRUE;
                                        break;
                                }
                                if (t < mintime) {
                                        mintime = t;
                                        min_kdbp = kdbp;
                                        min_cpu = cpu;
                                }
                        }
                        if (min_kdbp == NULL || out_of_events == TRUE) {
                                /*
                                 * all buffers ran empty
                                 */
                                out_of_events = TRUE;
                                break;
                        }

                        // Get data
                        kdsp = min_kdbp->kd_list_head;
                        kdsp_actual = POINTER_FROM_KDS_PTR(kdsp);

                        if (kdsp_actual->kds_lostevents == TRUE) {
                                kdbg_set_timestamp_and_cpu(&lostevent, kdsp_actual->kds_records[kdsp_actual->kds_readlast].timestamp, min_cpu);
                                *tempbuf = lostevent;
                                
                                kdsp_actual->kds_lostevents = FALSE;
                                lostevents = TRUE;

                                goto nextevent;
                        }

                        // Copy into buffer
                        *tempbuf = kdsp_actual->kds_records[kdsp_actual->kds_readlast++];

                        if (kdsp_actual->kds_readlast == EVENTS_PER_STORAGE_UNIT)
                                release_storage_unit(min_cpu, kdsp.raw);

                        /*
                         * Watch for out of order timestamps
                         */     
                        if (mintime < min_kdbp->kd_prev_timebase) {
                                /*
                                 * if so, use the previous timestamp + 1 cycle
                                 */
                                min_kdbp->kd_prev_timebase++;
                                kdbg_set_timestamp_and_cpu(tempbuf, min_kdbp->kd_prev_timebase, kdbg_get_cpu(tempbuf));
                        } else
                                min_kdbp->kd_prev_timebase = mintime;
nextevent:
                        tempbuf_count--;
                        tempbuf_number++;
                        tempbuf++;

                        if ((RAW_file_written += sizeof(kd_buf)) >= RAW_FLUSH_SIZE)
                                break;
                }
                if (tempbuf_number) {

                        if (vp) {
                                error = vn_rdwr(UIO_WRITE, vp, (caddr_t)kdcopybuf, tempbuf_number * sizeof(kd_buf), RAW_file_offset,
                                                UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, vfs_context_ucred(ctx), (int *) 0, vfs_context_proc(ctx));

                                RAW_file_offset += (tempbuf_number * sizeof(kd_buf));
        
                                if (RAW_file_written >= RAW_FLUSH_SIZE) {
                                        cluster_push(vp, 0);

                                        RAW_file_written = 0;
                                }
                        } else {
                                error = copyout(kdcopybuf, buffer, tempbuf_number * sizeof(kd_buf));
                                buffer += (tempbuf_number * sizeof(kd_buf));
                        }
                        if (error) {
                                *number = 0;
                                error = EINVAL;
                                break;
                        }
                        count   -= tempbuf_number;
                        *number += tempbuf_number;
                }
                if (out_of_events == TRUE)
                       /*
                        * all trace buffers are empty
                        */
                        break;

                if ((tempbuf_count = count) > KDCOPYBUF_COUNT)
                        tempbuf_count = KDCOPYBUF_COUNT;
        }
        if ( !(old_kdebug_flags & KDBG_NOWRAP)) {
                enable_wrap(old_kdebug_slowcheck, lostevents);
        }
        return (error);
}


unsigned char *getProcName(struct proc *proc);
unsigned char *getProcName(struct proc *proc) {

        return (unsigned char *) &proc->p_comm; /* Return pointer to the proc name */

}

#define STACKSHOT_SUBSYS_LOCK() lck_mtx_lock(&stackshot_subsys_mutex)
#define STACKSHOT_SUBSYS_UNLOCK() lck_mtx_unlock(&stackshot_subsys_mutex)
#if defined(__i386__) || defined (__x86_64__)
#define TRAP_DEBUGGER __asm__ volatile("int3");
#else
#error No TRAP_DEBUGGER definition for this architecture
#endif

#define SANE_TRACEBUF_SIZE (8 * 1024 * 1024)
#define SANE_BOOTPROFILE_TRACEBUF_SIZE (64 * 1024 * 1024)

/* Initialize the mutex governing access to the stack snapshot subsystem */
__private_extern__ void
stackshot_lock_init( void )
{
        stackshot_subsys_lck_grp_attr = lck_grp_attr_alloc_init();

        stackshot_subsys_lck_grp = lck_grp_alloc_init("stackshot_subsys_lock", stackshot_subsys_lck_grp_attr);

        stackshot_subsys_lck_attr = lck_attr_alloc_init();

        lck_mtx_init(&stackshot_subsys_mutex, stackshot_subsys_lck_grp, stackshot_subsys_lck_attr);
}

/*
 * stack_snapshot:   Obtains a coherent set of stack traces for all threads
 *                   on the system, tracing both kernel and user stacks
 *                   where available. Uses machine specific trace routines
 *                   for ppc, ppc64 and x86.
 * Inputs:           uap->pid - process id of process to be traced, or -1
 *                   for the entire system
 *                   uap->tracebuf - address of the user space destination
 *                   buffer 
 *                   uap->tracebuf_size - size of the user space trace buffer
 *                   uap->options - various options, including the maximum
 *                   number of frames to trace.
 * Outputs:          EPERM if the caller is not privileged
 *                   EINVAL if the supplied trace buffer isn't sanely sized
 *                   ENOMEM if we don't have enough memory to satisfy the
 *                   request
 *                   ENOENT if the target pid isn't found
 *                   ENOSPC if the supplied buffer is insufficient
 *                   *retval contains the number of bytes traced, if successful
 *                   and -1 otherwise. If the request failed due to
 *                   tracebuffer exhaustion, we copyout as much as possible.
 */
int
stack_snapshot(struct proc *p, register struct stack_snapshot_args *uap, int32_t *retval) {
        int error = 0;

        if ((error = suser(kauth_cred_get(), &p->p_acflag)))
                return(error);

        return stack_snapshot2(uap->pid, uap->tracebuf, uap->tracebuf_size,
            uap->flags, uap->dispatch_offset, retval);
}

int  
stack_snapshot_from_kernel(pid_t pid, void *buf, uint32_t size, uint32_t flags, unsigned *bytesTraced)
{
        int error = 0;
        boolean_t istate;

        if ((buf == NULL) || (size <= 0) || (bytesTraced == NULL)) {
                return -1;
        }

        /* cap in individual stackshot to SANE_TRACEBUF_SIZE */
        if (size > SANE_TRACEBUF_SIZE) {
                size = SANE_TRACEBUF_SIZE;
        }

/* Serialize tracing */ 
        STACKSHOT_SUBSYS_LOCK();
        istate = ml_set_interrupts_enabled(FALSE);


/* Preload trace parameters*/   
        kdp_snapshot_preflight(pid, buf, size, flags, 0);

/* Trap to the debugger to obtain a coherent stack snapshot; this populates
 * the trace buffer
 */
        TRAP_DEBUGGER;

        ml_set_interrupts_enabled(istate);

        *bytesTraced = kdp_stack_snapshot_bytes_traced();

        error = kdp_stack_snapshot_geterror();
        
        STACKSHOT_SUBSYS_UNLOCK();

    return error;

}

int
stack_snapshot2(pid_t pid, user_addr_t tracebuf, uint32_t tracebuf_size, uint32_t flags, uint32_t dispatch_offset, int32_t *retval)
{
        boolean_t istate;
        int error = 0;
        unsigned bytesTraced = 0;

#if CONFIG_TELEMETRY
        if (flags & STACKSHOT_GLOBAL_MICROSTACKSHOT_ENABLE) {
                telemetry_global_ctl(1);
                *retval = 0;
                return (0);
        } else if (flags & STACKSHOT_GLOBAL_MICROSTACKSHOT_DISABLE) {
                telemetry_global_ctl(0);
                *retval = 0;
                return (0);
        }

        if (flags & STACKSHOT_WINDOWED_MICROSTACKSHOTS_ENABLE) {
                error = telemetry_enable_window();

                if (error != KERN_SUCCESS) {
                        /* We are probably out of memory */
                        *retval = -1;
                        return ENOMEM;
                }

                *retval = 0;
                return (0);
        } else if (flags & STACKSHOT_WINDOWED_MICROSTACKSHOTS_DISABLE) {
                telemetry_disable_window();
                *retval = 0;
                return (0);
        }
#endif

        *retval = -1;
/* Serialize tracing */ 
        STACKSHOT_SUBSYS_LOCK();
        
        if (tracebuf_size <= 0) {
                error = EINVAL;
                goto error_exit;
        }

#if CONFIG_TELEMETRY
        if (flags & STACKSHOT_GET_MICROSTACKSHOT) {

                if (tracebuf_size > SANE_TRACEBUF_SIZE) {
                        error = EINVAL;
                        goto error_exit;
                }

                bytesTraced = tracebuf_size;
                error = telemetry_gather(tracebuf, &bytesTraced, 
                                         (flags & STACKSHOT_SET_MICROSTACKSHOT_MARK) ? TRUE : FALSE);
                if (error == KERN_NO_SPACE) {
                        error = ENOSPC;
                }

                *retval = (int)bytesTraced;
                goto error_exit;
        }

        if (flags & STACKSHOT_GET_WINDOWED_MICROSTACKSHOTS) {

                if (tracebuf_size > SANE_TRACEBUF_SIZE) {
                        error = EINVAL;
                        goto error_exit;
                }

                bytesTraced = tracebuf_size;
                error = telemetry_gather_windowed(tracebuf, &bytesTraced);
                if (error == KERN_NO_SPACE) {
                        error = ENOSPC;
                }

                *retval = (int)bytesTraced;
                goto error_exit;
        }

        if (flags & STACKSHOT_GET_BOOT_PROFILE) {

                if (tracebuf_size > SANE_BOOTPROFILE_TRACEBUF_SIZE) {
                        error = EINVAL;
                        goto error_exit;
                }

                bytesTraced = tracebuf_size;
                error = bootprofile_gather(tracebuf, &bytesTraced);
                if (error == KERN_NO_SPACE) {
                        error = ENOSPC;
                }

                *retval = (int)bytesTraced;
                goto error_exit;
        }
#endif

        if (tracebuf_size > SANE_TRACEBUF_SIZE) {
                error = EINVAL;
                goto error_exit;
        }

        assert(stackshot_snapbuf == NULL);
        if (kmem_alloc_kobject(kernel_map, (vm_offset_t *)&stackshot_snapbuf, tracebuf_size) != KERN_SUCCESS) {
                error = ENOMEM;
                goto error_exit;
        }

        if (panic_active()) {
                error = ENOMEM;
                goto error_exit;
        }

        istate = ml_set_interrupts_enabled(FALSE);
/* Preload trace parameters*/   
        kdp_snapshot_preflight(pid, stackshot_snapbuf, tracebuf_size, flags, dispatch_offset);

/* Trap to the debugger to obtain a coherent stack snapshot; this populates
 * the trace buffer
 */

        TRAP_DEBUGGER;

        ml_set_interrupts_enabled(istate);

        bytesTraced = kdp_stack_snapshot_bytes_traced();
                        
        if (bytesTraced > 0) {
                if ((error = copyout(stackshot_snapbuf, tracebuf,
                        ((bytesTraced < tracebuf_size) ?
                            bytesTraced : tracebuf_size))))
                        goto error_exit;
                *retval = bytesTraced;
        }
        else {
                error = ENOENT;
                goto error_exit;
        }

        error = kdp_stack_snapshot_geterror();
        if (error == -1) {
                error = ENOSPC;
                *retval = -1;
                goto error_exit;
        }

error_exit:
        if (stackshot_snapbuf != NULL)
                kmem_free(kernel_map, (vm_offset_t) stackshot_snapbuf, tracebuf_size);
        stackshot_snapbuf = NULL;
        STACKSHOT_SUBSYS_UNLOCK();
        return error;
}

void
start_kern_tracing(unsigned int new_nkdbufs, boolean_t need_map)
{

        if (!new_nkdbufs)
                return;
        nkdbufs = kdbg_set_nkdbufs(new_nkdbufs);
        kdbg_lock_init();

        kernel_debug_string("start_kern_tracing");

        if (0 == kdbg_reinit(TRUE)) {

                if (need_map == TRUE) {
                        uint32_t old1, old2;

                        kdbg_thrmap_init();

                        disable_wrap(&old1, &old2);
                }

                /* Hold off interrupts until the early traces are cut */
                boolean_t       s = ml_set_interrupts_enabled(FALSE);

                kdbg_set_tracing_enabled(
                        TRUE,
                        kdebug_serial ?
                                (KDEBUG_ENABLE_TRACE | KDEBUG_ENABLE_SERIAL) :
                                 KDEBUG_ENABLE_TRACE);

                /*
                 * Transfer all very early events from the static buffer
                 * into the real buffers.
                 */
                kernel_debug_early_end();
        
                ml_set_interrupts_enabled(s);

                printf("kernel tracing started\n");
#if KDEBUG_MOJO_TRACE
                if (kdebug_serial) {
                        printf("serial output enabled with %lu named events\n",
                        sizeof(kd_events)/sizeof(kd_event_t));
                }
#endif
        } else {
                printf("error from kdbg_reinit, kernel tracing not started\n");
        }
}

void
start_kern_tracing_with_typefilter(unsigned int new_nkdbufs,
                                   boolean_t need_map,
                                   unsigned int typefilter)
{
        /* startup tracing */
        start_kern_tracing(new_nkdbufs, need_map);

        /* check that tracing was actually enabled */
        if (!(kdebug_enable & KDEBUG_ENABLE_TRACE))
                return;

        /* setup the typefiltering */
        if (0 == kdbg_enable_typefilter())
                setbit(type_filter_bitmap, typefilter & (CSC_MASK >> CSC_OFFSET));
}

void
kdbg_dump_trace_to_file(const char *filename)
{
        vfs_context_t   ctx;
        vnode_t         vp;
        int             error;
        size_t          number;


        if ( !(kdebug_enable & KDEBUG_ENABLE_TRACE))
                return;

        if (global_state_pid != -1) {
                if ((proc_find(global_state_pid)) != NULL) {
                        /*
                         * The global pid exists, we're running
                         * due to fs_usage, latency, etc...
                         * don't cut the panic/shutdown trace file
                         * Disable tracing from this point to avoid
                         * perturbing state.
                         */
                        kdebug_enable = 0;
                        kd_ctrl_page.enabled = 0;
                        commpage_update_kdebug_enable();
                        return;
                }
        }
        KERNEL_DEBUG_CONSTANT(TRACE_PANIC | DBG_FUNC_NONE, 0, 0, 0, 0, 0);

        kdebug_enable = 0;
        kd_ctrl_page.enabled = 0;
        commpage_update_kdebug_enable();

        ctx = vfs_context_kernel();

        if ((error = vnode_open(filename, (O_CREAT | FWRITE | O_NOFOLLOW), 0600, 0, &vp, ctx)))
                return;

        number = kd_mapcount * sizeof(kd_threadmap);
        kdbg_readthrmap(0, &number, vp, ctx);

        number = nkdbufs*sizeof(kd_buf);
        kdbg_read(0, &number, vp, ctx);
        
        vnode_close(vp, FWRITE, ctx);

        sync(current_proc(), (void *)NULL, (int *)NULL);
}

/* Helper function for filling in the BSD name for an address space
 * Defined here because the machine bindings know only Mach threads
 * and nothing about BSD processes.
 *
 * FIXME: need to grab a lock during this?
 */
void kdbg_get_task_name(char* name_buf, int len, task_t task)
{
        proc_t proc;
        
        /* Note: we can't use thread->task (and functions that rely on it) here 
         * because it hasn't been initialized yet when this function is called.
         * We use the explicitly-passed task parameter instead.
         */
        proc = get_bsdtask_info(task);
        if (proc != PROC_NULL)
                snprintf(name_buf, len, "%s/%d", proc->p_comm, proc->p_pid);
        else
                snprintf(name_buf, len, "%p [!bsd]", task);
}

#if KDEBUG_MOJO_TRACE
static kd_event_t *
binary_search(uint32_t id)
{
        int low, high, mid;

        low = 0;
        high = sizeof(kd_events)/sizeof(kd_event_t) - 1;

        while (TRUE)
        {
                mid = (low + high) / 2;

                if (low > high)
                        return NULL; /* failed */
                else if ( low + 1 >= high) {
                        /* We have a match */
                        if (kd_events[high].id == id)
                                return &kd_events[high];
                        else if (kd_events[low].id == id)
                                return &kd_events[low];
                        else
                                return NULL;  /* search failed */
                }
                else if (id < kd_events[mid].id)
                        high = mid;
                else
                        low = mid;
        } 
}

/*
 * Look up event id to get name string.
 * Using a per-cpu cache of a single entry
 * before resorting to a binary search of the full table.
 */
#define NCACHE  1
static kd_event_t       *last_hit[MAX_CPUS];
static kd_event_t *
event_lookup_cache(uint32_t cpu, uint32_t id)
{
        if (last_hit[cpu] == NULL || last_hit[cpu]->id != id)
                last_hit[cpu] = binary_search(id);
        return last_hit[cpu];
}

static uint64_t kd_last_timstamp;

static void
kdebug_serial_print(
        uint32_t        cpunum,
        uint32_t        debugid,
        uint64_t        timestamp,
        uintptr_t       arg1,
        uintptr_t       arg2,
        uintptr_t       arg3,
        uintptr_t       arg4,
        uintptr_t       threadid
        )
{
        char            kprintf_line[192];
        char            event[40];
        uint64_t        us = timestamp / NSEC_PER_USEC;
        uint64_t        us_tenth = (timestamp % NSEC_PER_USEC) / 100;
        uint64_t        delta = timestamp - kd_last_timstamp;
        uint64_t        delta_us = delta / NSEC_PER_USEC;
        uint64_t        delta_us_tenth = (delta % NSEC_PER_USEC) / 100;
        uint32_t        event_id = debugid & DBG_FUNC_MASK;
        const char      *command;
        const char      *bra;
        const char      *ket;
        kd_event_t      *ep;

        /* event time and delta from last */
        snprintf(kprintf_line, sizeof(kprintf_line),
                "%11llu.%1llu %8llu.%1llu ",
                us, us_tenth, delta_us, delta_us_tenth);


        /* event (id or name) - start prefixed by "[", end postfixed by "]" */
        bra = (debugid & DBG_FUNC_START) ? "[" : " ";
        ket = (debugid & DBG_FUNC_END)   ? "]" : " ";
        ep = event_lookup_cache(cpunum, event_id);
        if (ep) {
                if (strlen(ep->name) < sizeof(event) - 3)
                        snprintf(event, sizeof(event), "%s%s%s",
                                 bra, ep->name, ket);
                else
                        snprintf(event, sizeof(event), "%s%x(name too long)%s",
                                 bra, event_id, ket);
        } else {
                snprintf(event, sizeof(event), "%s%x%s",
                         bra, event_id, ket);
        }
        snprintf(kprintf_line + strlen(kprintf_line),
                 sizeof(kprintf_line) - strlen(kprintf_line),
                 "%-40s  ", event);

        /* arg1 .. arg4 with special cases for strings */
        switch (event_id) {
            case VFS_LOOKUP:
            case VFS_LOOKUP_DONE:
                if (debugid & DBG_FUNC_START) {
                        /* arg1 hex then arg2..arg4 chars */
                        snprintf(kprintf_line + strlen(kprintf_line),
                                sizeof(kprintf_line) - strlen(kprintf_line),
                                "%-16lx %-8s%-8s%-8s                          ",
                                arg1, (char*)&arg2, (char*)&arg3, (char*)&arg4);
                        break;
                }
                /* else fall through for arg1..arg4 chars */
            case TRACE_STRING_EXEC:
            case TRACE_STRING_NEWTHREAD:
            case TRACE_INFO_STRING:
                snprintf(kprintf_line + strlen(kprintf_line),
                        sizeof(kprintf_line) - strlen(kprintf_line),
                        "%-8s%-8s%-8s%-8s                                   ",
                        (char*)&arg1, (char*)&arg2, (char*)&arg3, (char*)&arg4);
                break;
            default:
                snprintf(kprintf_line + strlen(kprintf_line),
                        sizeof(kprintf_line) - strlen(kprintf_line),
                        "%-16lx %-16lx %-16lx %-16lx",
                        arg1, arg2, arg3, arg4);
        }

        /* threadid, cpu and command name */
        if (threadid == (uintptr_t)thread_tid(current_thread()) &&
            current_proc() &&
            current_proc()->p_comm)
                command = current_proc()->p_comm;
        else
                command = "-";
        snprintf(kprintf_line + strlen(kprintf_line),
                sizeof(kprintf_line) - strlen(kprintf_line),
                "  %-16lx  %-2d %s\n",
                threadid, cpunum, command);
        
        kprintf("%s", kprintf_line);
        kd_last_timstamp = timestamp;
}
#endif