]> git.saurik.com Git - apple/xnu.git/blobdiff - osfmk/kperf/callstack.c
xnu-6153.11.26.tar.gz
[apple/xnu.git] / osfmk / kperf / callstack.c
index 7c8f0a7e79c71d226a752e2cba6fcd210410c288..d6f0fb9a9deaab402ea4904e78de49581a32453d 100644 (file)
@@ -2,7 +2,7 @@
  * Copyright (c) 2011 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
- * 
+ *
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
+ *
  * The 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,
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
+ *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
 /* Collect kernel callstacks */
 
-#include <chud/chud_xnu.h>
 #include <mach/mach_types.h>
 #include <kern/thread.h>
 #include <kern/backtrace.h>
 #endif
 
 static void
-callstack_fixup_user(struct callstack *cs, thread_t thread)
+callstack_fixup_user(struct kp_ucallstack *cs, thread_t thread)
 {
        uint64_t fixup_val = 0;
-       assert(cs->nframes < MAX_CALLSTACK_FRAMES);
+       assert(cs->kpuc_nframes < MAX_UCALLSTACK_FRAMES);
 
 #if defined(__x86_64__)
        user_addr_t sp_user;
@@ -62,17 +61,17 @@ callstack_fixup_user(struct callstack *cs, thread_t thread)
 
        user_64 = is_saved_state64(state);
        if (user_64) {
-           sp_user = saved_state64(state)->isf.rsp;
+               sp_user = saved_state64(state)->isf.rsp;
        } else {
                sp_user = saved_state32(state)->uesp;
        }
 
        if (thread == current_thread()) {
                (void)copyin(sp_user, (char *)&fixup_val,
-                       user_64 ? sizeof(uint64_t) : sizeof(uint32_t));
+                   user_64 ? sizeof(uint64_t) : sizeof(uint32_t));
        } else {
                (void)vm_map_read_user(get_task_map(get_threadtask(thread)), sp_user,
-                       &fixup_val, user_64 ? sizeof(uint64_t) : sizeof(uint32_t));
+                   &fixup_val, user_64 ? sizeof(uint64_t) : sizeof(uint32_t));
        }
 
 #elif defined(__arm64__) || defined(__arm__)
@@ -84,7 +83,7 @@ callstack_fixup_user(struct callstack *cs, thread_t thread)
 
        /* encode thumb mode into low bit of PC */
        if (get_saved_state_cpsr(state) & PSR_TF) {
-               cs->frames[0] |= 1ULL;
+               cs->kpuc_frames[0] |= 1ULL;
        }
 
        fixup_val = get_saved_state_lr(state);
@@ -94,7 +93,7 @@ callstack_fixup_user(struct callstack *cs, thread_t thread)
 #endif
 
 out:
-       cs->frames[cs->nframes++] = fixup_val;
+       cs->kpuc_frames[cs->kpuc_nframes++] = fixup_val;
 }
 
 #if defined(__x86_64__)
@@ -136,7 +135,7 @@ interrupted_kernel_sp_value(uintptr_t *sp_val)
        bottom = current_thread()->kernel_stack;
        top = bottom + kernel_stack_size;
        if (sp >= bottom && sp < top) {
-           return KERN_FAILURE;
+               return KERN_FAILURE;
        }
 
        *sp_val = *(uintptr_t *)sp;
@@ -187,10 +186,10 @@ interrupted_kernel_lr(uintptr_t *lr)
 
 
 static void
-callstack_fixup_interrupted(struct callstack *cs)
+callstack_fixup_interrupted(struct kp_kcallstack *cs)
 {
        uintptr_t fixup_val = 0;
-       assert(cs->nframes < MAX_CALLSTACK_FRAMES);
+       assert(cs->kpkc_nframes < MAX_KCALLSTACK_FRAMES);
 
        /*
         * Only provide arbitrary data on development or debug kernels.
@@ -203,12 +202,12 @@ callstack_fixup_interrupted(struct callstack *cs)
 #endif /* defined(__x86_64__) */
 #endif /* DEVELOPMENT || DEBUG */
 
-       assert(cs->flags & CALLSTACK_KERNEL);
-       cs->frames[cs->nframes++] = fixup_val;
+       assert(cs->kpkc_flags & CALLSTACK_KERNEL);
+       cs->kpkc_frames[cs->kpkc_nframes++] = fixup_val;
 }
 
 void
-kperf_continuation_sample(struct callstack *cs, struct kperf_context *context)
+kperf_continuation_sample(struct kp_kcallstack *cs, struct kperf_context *context)
 {
        thread_t thread;
 
@@ -219,135 +218,143 @@ kperf_continuation_sample(struct callstack *cs, struct kperf_context *context)
        assert(thread != NULL);
        assert(thread->continuation != NULL);
 
-       cs->flags = CALLSTACK_CONTINUATION | CALLSTACK_VALID | CALLSTACK_KERNEL;
+       cs->kpkc_flags = CALLSTACK_CONTINUATION | CALLSTACK_VALID | CALLSTACK_KERNEL;
 #ifdef __LP64__
-       cs->flags |= CALLSTACK_64BIT;
+       cs->kpkc_flags |= CALLSTACK_64BIT;
 #endif
 
-       cs->nframes = 1;
-       cs->frames[0] = VM_KERNEL_UNSLIDE(thread->continuation);
+       cs->kpkc_nframes = 1;
+       cs->kpkc_frames[0] = VM_KERNEL_UNSLIDE(thread->continuation);
 }
 
 void
-kperf_backtrace_sample(struct callstack *cs, struct kperf_context *context)
+kperf_backtrace_sample(struct kp_kcallstack *cs, struct kperf_context *context)
 {
        assert(cs != NULL);
        assert(context != NULL);
        assert(context->cur_thread == current_thread());
 
-       cs->flags = CALLSTACK_KERNEL | CALLSTACK_KERNEL_WORDS;
+       cs->kpkc_flags = CALLSTACK_KERNEL | CALLSTACK_KERNEL_WORDS;
 #ifdef __LP64__
-       cs->flags |= CALLSTACK_64BIT;
+       cs->kpkc_flags |= CALLSTACK_64BIT;
 #endif
 
        BUF_VERB(PERF_CS_BACKTRACE | DBG_FUNC_START, 1);
 
-       cs->nframes = backtrace_frame((uintptr_t *)&(cs->frames), cs->nframes - 1,
-                                     context->starting_fp);
-       if (cs->nframes > 0) {
-               cs->flags |= CALLSTACK_VALID;
+       bool trunc = false;
+       cs->kpkc_nframes = backtrace_frame(cs->kpkc_word_frames,
+           cs->kpkc_nframes - 1, context->starting_fp, &trunc);
+       if (cs->kpkc_nframes > 0) {
+               cs->kpkc_flags |= CALLSTACK_VALID;
                /*
                 * Fake the value pointed to by the stack pointer or the link
                 * register for symbolicators.
                 */
-               cs->frames[cs->nframes + 1] = 0;
-               cs->nframes += 1;
+               cs->kpkc_word_frames[cs->kpkc_nframes + 1] = 0;
+               cs->kpkc_nframes += 1;
+       }
+       if (trunc) {
+               cs->kpkc_nframes |= CALLSTACK_TRUNCATED;
        }
 
-       BUF_VERB(PERF_CS_BACKTRACE | DBG_FUNC_END, cs->nframes);
+       BUF_VERB(PERF_CS_BACKTRACE | DBG_FUNC_END, cs->kpkc_nframes);
 }
 
+kern_return_t chudxnu_thread_get_callstack64_kperf(thread_t thread,
+    uint64_t *callStack, mach_msg_type_number_t *count,
+    boolean_t user_only);
+
 void
-kperf_kcallstack_sample(struct callstack *cs, struct kperf_context *context)
+kperf_kcallstack_sample(struct kp_kcallstack *cs, struct kperf_context *context)
 {
        thread_t thread;
 
        assert(cs != NULL);
        assert(context != NULL);
-       assert(cs->nframes <= MAX_CALLSTACK_FRAMES);
+       assert(cs->kpkc_nframes <= MAX_KCALLSTACK_FRAMES);
 
        thread = context->cur_thread;
        assert(thread != NULL);
 
        BUF_INFO(PERF_CS_KSAMPLE | DBG_FUNC_START, (uintptr_t)thread_tid(thread),
-               cs->nframes);
-
-       cs->flags = CALLSTACK_KERNEL;
+           cs->kpkc_nframes);
 
+       cs->kpkc_flags = CALLSTACK_KERNEL;
 #ifdef __LP64__
-       cs->flags |= CALLSTACK_64BIT;
+       cs->kpkc_flags |= CALLSTACK_64BIT;
 #endif
 
        if (ml_at_interrupt_context()) {
                assert(thread == current_thread());
-               cs->flags |= CALLSTACK_KERNEL_WORDS;
-               cs->nframes = backtrace_interrupted((uintptr_t *)cs->frames,
-                       cs->nframes - 1);
-               if (cs->nframes != 0) {
+               cs->kpkc_flags |= CALLSTACK_KERNEL_WORDS;
+               bool trunc = false;
+               cs->kpkc_nframes = backtrace_interrupted(
+                   cs->kpkc_word_frames, cs->kpkc_nframes - 1, &trunc);
+               if (cs->kpkc_nframes != 0) {
                        callstack_fixup_interrupted(cs);
                }
+               if (trunc) {
+                       cs->kpkc_flags |= CALLSTACK_TRUNCATED;
+               }
        } else {
                /*
                 * Rely on legacy CHUD backtracer to backtrace kernel stacks on
                 * other threads.
                 */
                kern_return_t kr;
-               kr = chudxnu_thread_get_callstack64_kperf(thread, cs->frames,
-                       &cs->nframes, FALSE);
+               kr = chudxnu_thread_get_callstack64_kperf(thread,
+                   cs->kpkc_frames, &cs->kpkc_nframes, FALSE);
                if (kr == KERN_SUCCESS) {
-                       cs->flags |= CALLSTACK_VALID;
+                       cs->kpkc_flags |= CALLSTACK_VALID;
                } else if (kr == KERN_RESOURCE_SHORTAGE) {
-                       cs->flags |= CALLSTACK_VALID;
-                       cs->flags |= CALLSTACK_TRUNCATED;
+                       cs->kpkc_flags |= CALLSTACK_VALID;
+                       cs->kpkc_flags |= CALLSTACK_TRUNCATED;
                } else {
-                       cs->nframes = 0;
+                       cs->kpkc_nframes = 0;
                }
        }
 
-       if (cs->nframes == 0) {
+       if (!(cs->kpkc_flags & CALLSTACK_VALID)) {
                BUF_INFO(PERF_CS_ERROR, ERR_GETSTACK);
        }
 
-       BUF_INFO(PERF_CS_KSAMPLE | DBG_FUNC_END, (uintptr_t)thread_tid(thread), cs->flags, cs->nframes);
+       BUF_INFO(PERF_CS_KSAMPLE | DBG_FUNC_END, (uintptr_t)thread_tid(thread),
+           cs->kpkc_flags, cs->kpkc_nframes);
 }
 
 void
-kperf_ucallstack_sample(struct callstack *cs, struct kperf_context *context)
+kperf_ucallstack_sample(struct kp_ucallstack *cs, struct kperf_context *context)
 {
-       thread_t thread;
-       bool user_64 = false;
-       int err;
-
-       assert(cs != NULL);
-       assert(context != NULL);
-       assert(cs->nframes <= MAX_CALLSTACK_FRAMES);
        assert(ml_get_interrupts_enabled() == TRUE);
 
-       thread = context->cur_thread;
+       thread_t thread = context->cur_thread;
        assert(thread != NULL);
 
-       BUF_INFO(PERF_CS_USAMPLE | DBG_FUNC_START, (uintptr_t)thread_tid(thread),
-               cs->nframes);
+       BUF_INFO(PERF_CS_USAMPLE | DBG_FUNC_START,
+           (uintptr_t)thread_tid(thread), cs->kpuc_nframes);
 
-       cs->flags = 0;
-
-       err = backtrace_thread_user(thread, (uintptr_t *)cs->frames,
-               cs->nframes - 1, &cs->nframes, &user_64);
-       cs->flags |= CALLSTACK_KERNEL_WORDS;
-       if (user_64) {
-               cs->flags |= CALLSTACK_64BIT;
+       bool user64 = false;
+       bool trunc = false;
+       int err = backtrace_thread_user(thread, cs->kpuc_frames,
+           cs->kpuc_nframes - 1, &cs->kpuc_nframes, &user64, &trunc);
+       cs->kpuc_flags = CALLSTACK_KERNEL_WORDS;
+       if (user64) {
+               cs->kpuc_flags |= CALLSTACK_64BIT;
+       }
+       if (trunc) {
+               cs->kpuc_flags |= CALLSTACK_TRUNCATED;
        }
 
        if (!err || err == EFAULT) {
                callstack_fixup_user(cs, thread);
-               cs->flags |= CALLSTACK_VALID;
+               cs->kpuc_flags |= CALLSTACK_VALID;
        } else {
-               cs->nframes = 0;
+               cs->kpuc_nframes = 0;
                BUF_INFO(PERF_CS_ERROR, ERR_GETSTACK, err);
        }
 
        BUF_INFO(PERF_CS_USAMPLE | DBG_FUNC_END, (uintptr_t)thread_tid(thread),
-               cs->flags, cs->nframes);
+           cs->kpuc_flags, cs->kpuc_nframes);
 }
 
 static inline uintptr_t
@@ -375,58 +382,58 @@ scrub_frame(uint64_t *bt, int n_frames, int frame)
 }
 
 static void
-callstack_log(struct callstack *cs, uint32_t hcode, uint32_t dcode)
+callstack_log(uint32_t hdrid, uint32_t dataid, void *vframes,
+    unsigned int nframes, unsigned int flags)
 {
-       BUF_VERB(PERF_CS_LOG | DBG_FUNC_START, cs->flags, cs->nframes);
+       BUF_VERB(PERF_CS_LOG | DBG_FUNC_START, flags, nframes);
 
-       /* framing information for the stack */
-       BUF_DATA(hcode, cs->flags, cs->nframes);
+       BUF_DATA(hdrid, flags, nframes);
 
-       /* how many batches of 4 */
-       unsigned int nframes = cs->nframes;
-       unsigned int n = nframes / 4;
+       unsigned int nevts = nframes / 4;
        unsigned int ovf = nframes % 4;
        if (ovf != 0) {
-               n++;
+               nevts++;
        }
 
-       bool kern = cs->flags & CALLSTACK_KERNEL;
+       bool kern = flags & CALLSTACK_KERNEL;
 
-       if (cs->flags & CALLSTACK_KERNEL_WORDS) {
-               uintptr_t *frames = (uintptr_t *)cs->frames;
-               for (unsigned int i = 0; i < n; i++) {
+       if (flags & CALLSTACK_KERNEL_WORDS) {
+               uintptr_t *frames = vframes;
+               for (unsigned int i = 0; i < nevts; i++) {
                        unsigned int j = i * 4;
-                       BUF_DATA(dcode,
-                               scrub_word(frames, nframes, j + 0, kern),
-                               scrub_word(frames, nframes, j + 1, kern),
-                               scrub_word(frames, nframes, j + 2, kern),
-                               scrub_word(frames, nframes, j + 3, kern));
+                       BUF_DATA(dataid,
+                           scrub_word(frames, nframes, j + 0, kern),
+                           scrub_word(frames, nframes, j + 1, kern),
+                           scrub_word(frames, nframes, j + 2, kern),
+                           scrub_word(frames, nframes, j + 3, kern));
                }
        } else {
-               for (unsigned int i = 0; i < n; i++) {
-                       uint64_t *frames = cs->frames;
+               for (unsigned int i = 0; i < nevts; i++) {
+                       uint64_t *frames = vframes;
                        unsigned int j = i * 4;
-                       BUF_DATA(dcode,
-                               scrub_frame(frames, nframes, j + 0),
-                               scrub_frame(frames, nframes, j + 1),
-                               scrub_frame(frames, nframes, j + 2),
-                               scrub_frame(frames, nframes, j + 3));
+                       BUF_DATA(dataid,
+                           scrub_frame(frames, nframes, j + 0),
+                           scrub_frame(frames, nframes, j + 1),
+                           scrub_frame(frames, nframes, j + 2),
+                           scrub_frame(frames, nframes, j + 3));
                }
        }
 
-       BUF_VERB(PERF_CS_LOG | DBG_FUNC_END, cs->flags, cs->nframes);
+       BUF_VERB(PERF_CS_LOG | DBG_FUNC_END, flags, nframes);
 }
 
 void
-kperf_kcallstack_log( struct callstack *cs )
+kperf_kcallstack_log(struct kp_kcallstack *cs)
 {
-       callstack_log(cs, PERF_CS_KHDR, PERF_CS_KDATA);
+       callstack_log(PERF_CS_KHDR, PERF_CS_KDATA, cs->kpkc_frames,
+           cs->kpkc_nframes, cs->kpkc_flags);
 }
 
 void
-kperf_ucallstack_log( struct callstack *cs )
+kperf_ucallstack_log(struct kp_ucallstack *cs)
 {
-       callstack_log(cs, PERF_CS_UHDR, PERF_CS_UDATA);
+       callstack_log(PERF_CS_UHDR, PERF_CS_UDATA, cs->kpuc_frames,
+           cs->kpuc_nframes, cs->kpuc_flags);
 }
 
 int
@@ -437,3 +444,1079 @@ kperf_ucallstack_pend(struct kperf_context * context, uint32_t depth)
 
        return did_pend;
 }
+
+static kern_return_t
+chudxnu_kern_read(void *dstaddr, vm_offset_t srcaddr, vm_size_t size)
+{
+       return (ml_nofault_copy(srcaddr, (vm_offset_t)dstaddr, size) == size) ?
+              KERN_SUCCESS : KERN_FAILURE;
+}
+
+static kern_return_t
+chudxnu_task_read(
+       task_t      task,
+       void        *kernaddr,
+       uint64_t    usraddr,
+       vm_size_t   size)
+{
+       //ppc version ported to arm
+       kern_return_t ret = KERN_SUCCESS;
+
+       if (ml_at_interrupt_context()) {
+               return KERN_FAILURE;    // can't look at tasks on interrupt stack
+       }
+
+       if (current_task() == task) {
+               if (copyin(usraddr, kernaddr, size)) {
+                       ret = KERN_FAILURE;
+               }
+       } else {
+               vm_map_t map = get_task_map(task);
+               ret = vm_map_read_user(map, usraddr, kernaddr, size);
+       }
+
+       return ret;
+}
+
+static inline uint64_t
+chudxnu_vm_unslide( uint64_t ptr, int kaddr )
+{
+       if (!kaddr) {
+               return ptr;
+       }
+
+       return VM_KERNEL_UNSLIDE(ptr);
+}
+
+#if __arm__
+#define ARM_SUPERVISOR_MODE(cpsr) ((((cpsr) & PSR_MODE_MASK) != PSR_USER_MODE) ? TRUE : FALSE)
+#define CS_FLAG_EXTRASP  1  // capture extra sp register
+static kern_return_t
+chudxnu_thread_get_callstack64_internal(
+       thread_t                thread,
+       uint64_t                *callStack,
+       mach_msg_type_number_t  *count,
+       boolean_t               user_only,
+       int flags)
+{
+       kern_return_t kr;
+       task_t                  task;
+       uint64_t                currPC = 0ULL, currLR = 0ULL, currSP = 0ULL;
+       uint64_t                prevPC = 0ULL;
+       uint32_t                kernStackMin = thread->kernel_stack;
+       uint32_t                kernStackMax = kernStackMin + kernel_stack_size;
+       uint64_t       *buffer = callStack;
+       uint32_t                frame[2];
+       int             bufferIndex = 0;
+       int             bufferMaxIndex = 0;
+       boolean_t       supervisor = FALSE;
+       struct arm_saved_state *state = NULL;
+       uint32_t                *fp = NULL, *nextFramePointer = NULL, *topfp = NULL;
+       uint64_t                pc = 0ULL;
+
+       task = get_threadtask(thread);
+
+       bufferMaxIndex = *count;
+       //get thread state
+       if (user_only) {
+               state = find_user_regs(thread);
+       } else {
+               state = find_kern_regs(thread);
+       }
+
+       if (!state) {
+               *count = 0;
+               return KERN_FAILURE;
+       }
+
+       /* make sure it is safe to dereference before you do it */
+       supervisor = ARM_SUPERVISOR_MODE(state->cpsr);
+
+       /* can't take a kernel callstack if we've got a user frame */
+       if (!user_only && !supervisor) {
+               return KERN_FAILURE;
+       }
+
+       /*
+        * Reserve space for saving LR (and sometimes SP) at the end of the
+        * backtrace.
+        */
+       if (flags & CS_FLAG_EXTRASP) {
+               bufferMaxIndex -= 2;
+       } else {
+               bufferMaxIndex -= 1;
+       }
+
+       if (bufferMaxIndex < 2) {
+               *count = 0;
+               return KERN_RESOURCE_SHORTAGE;
+       }
+
+       currPC = (uint64_t)state->pc; /* r15 */
+       if (state->cpsr & PSR_TF) {
+               currPC |= 1ULL; /* encode thumb mode into low bit of PC */
+       }
+       currLR = (uint64_t)state->lr; /* r14 */
+       currSP = (uint64_t)state->sp; /* r13 */
+
+       fp = (uint32_t *)state->r[7]; /* frame pointer */
+       topfp = fp;
+
+       bufferIndex = 0;  // start with a stack of size zero
+       buffer[bufferIndex++] = chudxnu_vm_unslide(currPC, supervisor); // save PC in position 0.
+
+       // Now, fill buffer with stack backtraces.
+       while (bufferIndex < bufferMaxIndex) {
+               pc = 0ULL;
+               /*
+                * Below the frame pointer, the following values are saved:
+                * -> FP
+                */
+
+               /*
+                * Note that we read the pc even for the first stack frame
+                * (which, in theory, is always empty because the callee fills
+                * it in just before it lowers the stack.  However, if we
+                * catch the program in between filling in the return address
+                * and lowering the stack, we want to still have a valid
+                * backtrace. FixupStack correctly disregards this value if
+                * necessary.
+                */
+
+               if ((uint32_t)fp == 0 || ((uint32_t)fp & 0x3) != 0) {
+                       /* frame pointer is invalid - stop backtracing */
+                       pc = 0ULL;
+                       break;
+               }
+
+               if (supervisor) {
+                       if (((uint32_t)fp > kernStackMax) ||
+                           ((uint32_t)fp < kernStackMin)) {
+                               kr = KERN_FAILURE;
+                       } else {
+                               kr = chudxnu_kern_read(&frame,
+                                   (vm_offset_t)fp,
+                                   (vm_size_t)sizeof(frame));
+                               if (kr == KERN_SUCCESS) {
+                                       pc = (uint64_t)frame[1];
+                                       nextFramePointer = (uint32_t *) (frame[0]);
+                               } else {
+                                       pc = 0ULL;
+                                       nextFramePointer = 0ULL;
+                                       kr = KERN_FAILURE;
+                               }
+                       }
+               } else {
+                       kr = chudxnu_task_read(task,
+                           &frame,
+                           (((uint64_t)(uint32_t)fp) & 0x00000000FFFFFFFFULL),
+                           sizeof(frame));
+                       if (kr == KERN_SUCCESS) {
+                               pc = (uint64_t) frame[1];
+                               nextFramePointer = (uint32_t *) (frame[0]);
+                       } else {
+                               pc = 0ULL;
+                               nextFramePointer = 0ULL;
+                               kr = KERN_FAILURE;
+                       }
+               }
+
+               if (kr != KERN_SUCCESS) {
+                       pc = 0ULL;
+                       break;
+               }
+
+               if (nextFramePointer) {
+                       buffer[bufferIndex++] = chudxnu_vm_unslide(pc, supervisor);
+                       prevPC = pc;
+               }
+
+               if (nextFramePointer < fp) {
+                       break;
+               } else {
+                       fp = nextFramePointer;
+               }
+       }
+
+       if (bufferIndex >= bufferMaxIndex) {
+               bufferIndex = bufferMaxIndex;
+               kr = KERN_RESOURCE_SHORTAGE;
+       } else {
+               kr = KERN_SUCCESS;
+       }
+
+       // Save link register and R13 (sp) at bottom of stack (used for later fixup).
+       buffer[bufferIndex++] = chudxnu_vm_unslide(currLR, supervisor);
+       if (flags & CS_FLAG_EXTRASP) {
+               buffer[bufferIndex++] = chudxnu_vm_unslide(currSP, supervisor);
+       }
+
+       *count = bufferIndex;
+       return kr;
+}
+
+kern_return_t
+chudxnu_thread_get_callstack64_kperf(
+       thread_t                thread,
+       uint64_t                *callStack,
+       mach_msg_type_number_t  *count,
+       boolean_t               user_only)
+{
+       return chudxnu_thread_get_callstack64_internal( thread, callStack, count, user_only, 0 );
+}
+#elif __arm64__
+
+#if defined(HAS_APPLE_PAC)
+#include <ptrauth.h>
+#endif
+
+// chudxnu_thread_get_callstack gathers a raw callstack along with any information needed to
+// fix it up later (in case we stopped program as it was saving values into prev stack frame, etc.)
+// after sampling has finished.
+//
+// For an N-entry callstack:
+//
+// [0]      current pc
+// [1..N-3] stack frames (including current one)
+// [N-2]    current LR (return value if we're in a leaf function)
+// [N-1]    current r0 (in case we've saved LR in r0) (optional)
+//
+//
+#define ARM_SUPERVISOR_MODE(cpsr) ((((cpsr) & PSR_MODE_MASK) != PSR_USER_MODE) ? TRUE : FALSE)
+
+#define CS_FLAG_EXTRASP  1  // capture extra sp register
+
+static kern_return_t
+chudxnu_thread_get_callstack64_internal(
+       thread_t                thread,
+       uint64_t                *callStack,
+       mach_msg_type_number_t  *count,
+       boolean_t               user_only,
+       int flags)
+{
+       kern_return_t   kr = KERN_SUCCESS;
+       task_t                  task;
+       uint64_t                currPC = 0ULL, currLR = 0ULL, currSP = 0ULL;
+       uint64_t                prevPC = 0ULL;
+       uint64_t                kernStackMin = thread->kernel_stack;
+       uint64_t                kernStackMax = kernStackMin + kernel_stack_size;
+       uint64_t       *buffer = callStack;
+       int             bufferIndex = 0;
+       int             bufferMaxIndex = 0;
+       boolean_t       kernel = FALSE;
+       struct arm_saved_state *sstate = NULL;
+       uint64_t                pc = 0ULL;
+
+       task = get_threadtask(thread);
+       bufferMaxIndex = *count;
+       //get thread state
+       if (user_only) {
+               sstate = find_user_regs(thread);
+       } else {
+               sstate = find_kern_regs(thread);
+       }
+
+       if (!sstate) {
+               *count = 0;
+               return KERN_FAILURE;
+       }
+
+       if (is_saved_state64(sstate)) {
+               struct arm_saved_state64 *state = NULL;
+               uint64_t *fp = NULL, *nextFramePointer = NULL, *topfp = NULL;
+               uint64_t frame[2];
+
+               state = saved_state64(sstate);
+
+               /* make sure it is safe to dereference before you do it */
+               kernel = PSR64_IS_KERNEL(state->cpsr);
+
+               /* can't take a kernel callstack if we've got a user frame */
+               if (!user_only && !kernel) {
+                       return KERN_FAILURE;
+               }
+
+               /*
+                * Reserve space for saving LR (and sometimes SP) at the end of the
+                * backtrace.
+                */
+               if (flags & CS_FLAG_EXTRASP) {
+                       bufferMaxIndex -= 2;
+               } else {
+                       bufferMaxIndex -= 1;
+               }
+
+               if (bufferMaxIndex < 2) {
+                       *count = 0;
+                       return KERN_RESOURCE_SHORTAGE;
+               }
+
+               currPC = state->pc;
+               currLR = state->lr;
+               currSP = state->sp;
+
+               fp = (uint64_t *)state->fp; /* frame pointer */
+               topfp = fp;
+
+               bufferIndex = 0;  // start with a stack of size zero
+               buffer[bufferIndex++] = chudxnu_vm_unslide(currPC, kernel); // save PC in position 0.
+
+               BUF_VERB(PERF_CS_BACKTRACE | DBG_FUNC_START, kernel, 0);
+
+               // Now, fill buffer with stack backtraces.
+               while (bufferIndex < bufferMaxIndex) {
+                       pc = 0ULL;
+                       /*
+                        * Below the frame pointer, the following values are saved:
+                        * -> FP
+                        */
+
+                       /*
+                        * Note that we read the pc even for the first stack frame
+                        * (which, in theory, is always empty because the callee fills
+                        * it in just before it lowers the stack.  However, if we
+                        * catch the program in between filling in the return address
+                        * and lowering the stack, we want to still have a valid
+                        * backtrace. FixupStack correctly disregards this value if
+                        * necessary.
+                        */
+
+                       if ((uint64_t)fp == 0 || ((uint64_t)fp & 0x3) != 0) {
+                               /* frame pointer is invalid - stop backtracing */
+                               pc = 0ULL;
+                               break;
+                       }
+
+                       if (kernel) {
+                               if (((uint64_t)fp > kernStackMax) ||
+                                   ((uint64_t)fp < kernStackMin)) {
+                                       kr = KERN_FAILURE;
+                               } else {
+                                       kr = chudxnu_kern_read(&frame,
+                                           (vm_offset_t)fp,
+                                           (vm_size_t)sizeof(frame));
+                                       if (kr == KERN_SUCCESS) {
+#if defined(HAS_APPLE_PAC)
+                                               /* return addresses on stack will be signed by arm64e ABI */
+                                               pc = (uint64_t)ptrauth_strip((void *)frame[1], ptrauth_key_return_address);
+#else
+                                               pc = frame[1];
+#endif
+                                               nextFramePointer = (uint64_t *)frame[0];
+                                       } else {
+                                               pc = 0ULL;
+                                               nextFramePointer = 0ULL;
+                                               kr = KERN_FAILURE;
+                                       }
+                               }
+                       } else {
+                               kr = chudxnu_task_read(task,
+                                   &frame,
+                                   (vm_offset_t)fp,
+                                   (vm_size_t)sizeof(frame));
+                               if (kr == KERN_SUCCESS) {
+#if defined(HAS_APPLE_PAC)
+                                       /* return addresses on stack will be signed by arm64e ABI */
+                                       pc = (uint64_t)ptrauth_strip((void *)frame[1], ptrauth_key_return_address);
+#else
+                                       pc = frame[1];
+#endif
+                                       nextFramePointer = (uint64_t *)(frame[0]);
+                               } else {
+                                       pc = 0ULL;
+                                       nextFramePointer = 0ULL;
+                                       kr = KERN_FAILURE;
+                               }
+                       }
+
+                       if (kr != KERN_SUCCESS) {
+                               pc = 0ULL;
+                               break;
+                       }
+
+                       if (nextFramePointer) {
+                               buffer[bufferIndex++] = chudxnu_vm_unslide(pc, kernel);
+                               prevPC = pc;
+                       }
+
+                       if (nextFramePointer < fp) {
+                               break;
+                       } else {
+                               fp = nextFramePointer;
+                       }
+               }
+
+               BUF_VERB(PERF_CS_BACKTRACE | DBG_FUNC_END, bufferIndex);
+
+               if (bufferIndex >= bufferMaxIndex) {
+                       bufferIndex = bufferMaxIndex;
+                       kr = KERN_RESOURCE_SHORTAGE;
+               } else {
+                       kr = KERN_SUCCESS;
+               }
+
+               // Save link register and SP at bottom of stack (used for later fixup).
+               buffer[bufferIndex++] = chudxnu_vm_unslide(currLR, kernel);
+               if (flags & CS_FLAG_EXTRASP) {
+                       buffer[bufferIndex++] = chudxnu_vm_unslide(currSP, kernel);
+               }
+       } else {
+               struct arm_saved_state32 *state = NULL;
+               uint32_t *fp = NULL, *nextFramePointer = NULL, *topfp = NULL;
+
+               /* 64-bit kernel stacks, 32-bit user stacks */
+               uint64_t frame[2];
+               uint32_t frame32[2];
+
+               state = saved_state32(sstate);
+
+               /* make sure it is safe to dereference before you do it */
+               kernel = ARM_SUPERVISOR_MODE(state->cpsr);
+
+               /* can't take a kernel callstack if we've got a user frame */
+               if (!user_only && !kernel) {
+                       return KERN_FAILURE;
+               }
+
+               /*
+                * Reserve space for saving LR (and sometimes SP) at the end of the
+                * backtrace.
+                */
+               if (flags & CS_FLAG_EXTRASP) {
+                       bufferMaxIndex -= 2;
+               } else {
+                       bufferMaxIndex -= 1;
+               }
+
+               if (bufferMaxIndex < 2) {
+                       *count = 0;
+                       return KERN_RESOURCE_SHORTAGE;
+               }
+
+               currPC = (uint64_t)state->pc; /* r15 */
+               if (state->cpsr & PSR_TF) {
+                       currPC |= 1ULL; /* encode thumb mode into low bit of PC */
+               }
+               currLR = (uint64_t)state->lr; /* r14 */
+               currSP = (uint64_t)state->sp; /* r13 */
+
+               fp = (uint32_t *)(uintptr_t)state->r[7]; /* frame pointer */
+               topfp = fp;
+
+               bufferIndex = 0;  // start with a stack of size zero
+               buffer[bufferIndex++] = chudxnu_vm_unslide(currPC, kernel); // save PC in position 0.
+
+               BUF_VERB(PERF_CS_BACKTRACE | DBG_FUNC_START, kernel, 1);
+
+               // Now, fill buffer with stack backtraces.
+               while (bufferIndex < bufferMaxIndex) {
+                       pc = 0ULL;
+                       /*
+                        * Below the frame pointer, the following values are saved:
+                        * -> FP
+                        */
+
+                       /*
+                        * Note that we read the pc even for the first stack frame
+                        * (which, in theory, is always empty because the callee fills
+                        * it in just before it lowers the stack.  However, if we
+                        * catch the program in between filling in the return address
+                        * and lowering the stack, we want to still have a valid
+                        * backtrace. FixupStack correctly disregards this value if
+                        * necessary.
+                        */
+
+                       if ((uint32_t)fp == 0 || ((uint32_t)fp & 0x3) != 0) {
+                               /* frame pointer is invalid - stop backtracing */
+                               pc = 0ULL;
+                               break;
+                       }
+
+                       if (kernel) {
+                               if (((uint32_t)fp > kernStackMax) ||
+                                   ((uint32_t)fp < kernStackMin)) {
+                                       kr = KERN_FAILURE;
+                               } else {
+                                       kr = chudxnu_kern_read(&frame,
+                                           (vm_offset_t)fp,
+                                           (vm_size_t)sizeof(frame));
+                                       if (kr == KERN_SUCCESS) {
+                                               pc = (uint64_t)frame[1];
+                                               nextFramePointer = (uint32_t *) (frame[0]);
+                                       } else {
+                                               pc = 0ULL;
+                                               nextFramePointer = 0ULL;
+                                               kr = KERN_FAILURE;
+                                       }
+                               }
+                       } else {
+                               kr = chudxnu_task_read(task,
+                                   &frame32,
+                                   (((uint64_t)(uint32_t)fp) & 0x00000000FFFFFFFFULL),
+                                   sizeof(frame32));
+                               if (kr == KERN_SUCCESS) {
+                                       pc = (uint64_t)frame32[1];
+                                       nextFramePointer = (uint32_t *)(uintptr_t)(frame32[0]);
+                               } else {
+                                       pc = 0ULL;
+                                       nextFramePointer = 0ULL;
+                                       kr = KERN_FAILURE;
+                               }
+                       }
+
+                       if (kr != KERN_SUCCESS) {
+                               pc = 0ULL;
+                               break;
+                       }
+
+                       if (nextFramePointer) {
+                               buffer[bufferIndex++] = chudxnu_vm_unslide(pc, kernel);
+                               prevPC = pc;
+                       }
+
+                       if (nextFramePointer < fp) {
+                               break;
+                       } else {
+                               fp = nextFramePointer;
+                       }
+               }
+
+               BUF_VERB(PERF_CS_BACKTRACE | DBG_FUNC_END, bufferIndex);
+
+               /* clamp callstack size to max */
+               if (bufferIndex >= bufferMaxIndex) {
+                       bufferIndex = bufferMaxIndex;
+                       kr = KERN_RESOURCE_SHORTAGE;
+               } else {
+                       /* ignore all other failures */
+                       kr = KERN_SUCCESS;
+               }
+
+               // Save link register and R13 (sp) at bottom of stack (used for later fixup).
+               buffer[bufferIndex++] = chudxnu_vm_unslide(currLR, kernel);
+               if (flags & CS_FLAG_EXTRASP) {
+                       buffer[bufferIndex++] = chudxnu_vm_unslide(currSP, kernel);
+               }
+       }
+
+       *count = bufferIndex;
+       return kr;
+}
+
+kern_return_t
+chudxnu_thread_get_callstack64_kperf(
+       thread_t                thread,
+       uint64_t                *callStack,
+       mach_msg_type_number_t  *count,
+       boolean_t               user_only)
+{
+       return chudxnu_thread_get_callstack64_internal( thread, callStack, count, user_only, 0 );
+}
+#elif __x86_64__
+
+#define VALID_STACK_ADDRESS(supervisor, addr, minKernAddr, maxKernAddr)   (supervisor ? (addr>=minKernAddr && addr<=maxKernAddr) : TRUE)
+// don't try to read in the hole
+#define VALID_STACK_ADDRESS64(supervisor, addr, minKernAddr, maxKernAddr) \
+(supervisor ? ((uint64_t)addr >= minKernAddr && (uint64_t)addr <= maxKernAddr) : \
+((uint64_t)addr != 0ULL && ((uint64_t)addr <= 0x00007FFFFFFFFFFFULL || (uint64_t)addr >= 0xFFFF800000000000ULL)))
+
+typedef struct _cframe64_t {
+       uint64_t        prevFP;         // can't use a real pointer here until we're a 64 bit kernel
+       uint64_t        caller;
+       uint64_t        args[0];
+}cframe64_t;
+
+
+typedef struct _cframe_t {
+       uint32_t                prev;   // this is really a user32-space pointer to the previous frame
+       uint32_t                caller;
+       uint32_t                args[0];
+} cframe_t;
+
+extern void * find_user_regs(thread_t);
+extern x86_saved_state32_t *find_kern_regs(thread_t);
+
+static kern_return_t
+do_kernel_backtrace(
+       thread_t thread,
+       struct x86_kernel_state *regs,
+       uint64_t *frames,
+       mach_msg_type_number_t *start_idx,
+       mach_msg_type_number_t max_idx)
+{
+       uint64_t kernStackMin = (uint64_t)thread->kernel_stack;
+       uint64_t kernStackMax = (uint64_t)kernStackMin + kernel_stack_size;
+       mach_msg_type_number_t ct = *start_idx;
+       kern_return_t kr = KERN_FAILURE;
+
+#if __LP64__
+       uint64_t currPC = 0ULL;
+       uint64_t currFP = 0ULL;
+       uint64_t prevPC = 0ULL;
+       uint64_t prevFP = 0ULL;
+       if (KERN_SUCCESS != chudxnu_kern_read(&currPC, (vm_offset_t)&(regs->k_rip), sizeof(uint64_t))) {
+               return KERN_FAILURE;
+       }
+       if (KERN_SUCCESS != chudxnu_kern_read(&currFP, (vm_offset_t)&(regs->k_rbp), sizeof(uint64_t))) {
+               return KERN_FAILURE;
+       }
+#else
+       uint32_t currPC = 0U;
+       uint32_t currFP = 0U;
+       uint32_t prevPC = 0U;
+       uint32_t prevFP = 0U;
+       if (KERN_SUCCESS != chudxnu_kern_read(&currPC, (vm_offset_t)&(regs->k_eip), sizeof(uint32_t))) {
+               return KERN_FAILURE;
+       }
+       if (KERN_SUCCESS != chudxnu_kern_read(&currFP, (vm_offset_t)&(regs->k_ebp), sizeof(uint32_t))) {
+               return KERN_FAILURE;
+       }
+#endif
+
+       if (*start_idx >= max_idx) {
+               return KERN_RESOURCE_SHORTAGE;  // no frames traced
+       }
+       if (!currPC) {
+               return KERN_FAILURE;
+       }
+
+       frames[ct++] = chudxnu_vm_unslide((uint64_t)currPC, 1);
+
+       // build a backtrace of this kernel state
+#if __LP64__
+       while (VALID_STACK_ADDRESS64(TRUE, currFP, kernStackMin, kernStackMax)) {
+               // this is the address where caller lives in the user thread
+               uint64_t caller = currFP + sizeof(uint64_t);
+#else
+       while (VALID_STACK_ADDRESS(TRUE, currFP, kernStackMin, kernStackMax)) {
+               uint32_t caller = (uint32_t)currFP + sizeof(uint32_t);
+#endif
+
+               if (!currFP || !currPC) {
+                       currPC = 0;
+                       break;
+               }
+
+               if (ct >= max_idx) {
+                       *start_idx = ct;
+                       return KERN_RESOURCE_SHORTAGE;
+               }
+
+               /* read our caller */
+               kr = chudxnu_kern_read(&currPC, (vm_offset_t)caller, sizeof(currPC));
+
+               if (kr != KERN_SUCCESS || !currPC) {
+                       currPC = 0UL;
+                       break;
+               }
+
+               /*
+                * retrive contents of the frame pointer and advance to the next stack
+                * frame if it's valid
+                */
+               prevFP = 0;
+               kr = chudxnu_kern_read(&prevFP, (vm_offset_t)currFP, sizeof(currPC));
+
+#if __LP64__
+               if (VALID_STACK_ADDRESS64(TRUE, prevFP, kernStackMin, kernStackMax)) {
+#else
+               if (VALID_STACK_ADDRESS(TRUE, prevFP, kernStackMin, kernStackMax)) {
+#endif
+                       frames[ct++] = chudxnu_vm_unslide((uint64_t)currPC, 1);
+                       prevPC = currPC;
+               }
+               if (prevFP <= currFP) {
+                       break;
+               } else {
+                       currFP = prevFP;
+               }
+       }
+
+       *start_idx = ct;
+       return KERN_SUCCESS;
+}
+
+
+
+static kern_return_t
+do_backtrace32(
+       task_t task,
+       thread_t thread,
+       x86_saved_state32_t *regs,
+       uint64_t *frames,
+       mach_msg_type_number_t *start_idx,
+       mach_msg_type_number_t max_idx,
+       boolean_t supervisor)
+{
+       uint32_t tmpWord = 0UL;
+       uint64_t currPC = (uint64_t) regs->eip;
+       uint64_t currFP = (uint64_t) regs->ebp;
+       uint64_t prevPC = 0ULL;
+       uint64_t prevFP = 0ULL;
+       uint64_t kernStackMin = thread->kernel_stack;
+       uint64_t kernStackMax = kernStackMin + kernel_stack_size;
+       mach_msg_type_number_t ct = *start_idx;
+       kern_return_t kr = KERN_FAILURE;
+
+       if (ct >= max_idx) {
+               return KERN_RESOURCE_SHORTAGE;  // no frames traced
+       }
+       frames[ct++] = chudxnu_vm_unslide(currPC, supervisor);
+
+       // build a backtrace of this 32 bit state.
+       while (VALID_STACK_ADDRESS(supervisor, currFP, kernStackMin, kernStackMax)) {
+               cframe_t *fp = (cframe_t *) (uintptr_t) currFP;
+
+               if (!currFP) {
+                       currPC = 0;
+                       break;
+               }
+
+               if (ct >= max_idx) {
+                       *start_idx = ct;
+                       return KERN_RESOURCE_SHORTAGE;
+               }
+
+               /* read our caller */
+               if (supervisor) {
+                       kr = chudxnu_kern_read(&tmpWord, (vm_offset_t) &fp->caller, sizeof(uint32_t));
+               } else {
+                       kr = chudxnu_task_read(task, &tmpWord, (vm_offset_t) &fp->caller, sizeof(uint32_t));
+               }
+
+               if (kr != KERN_SUCCESS) {
+                       currPC = 0ULL;
+                       break;
+               }
+
+               currPC = (uint64_t) tmpWord;    // promote 32 bit address
+
+               /*
+                * retrive contents of the frame pointer and advance to the next stack
+                * frame if it's valid
+                */
+               prevFP = 0;
+               if (supervisor) {
+                       kr = chudxnu_kern_read(&tmpWord, (vm_offset_t)&fp->prev, sizeof(uint32_t));
+               } else {
+                       kr = chudxnu_task_read(task, &tmpWord, (vm_offset_t)&fp->prev, sizeof(uint32_t));
+               }
+               prevFP = (uint64_t) tmpWord;    // promote 32 bit address
+
+               if (prevFP) {
+                       frames[ct++] = chudxnu_vm_unslide(currPC, supervisor);
+                       prevPC = currPC;
+               }
+               if (prevFP < currFP) {
+                       break;
+               } else {
+                       currFP = prevFP;
+               }
+       }
+
+       *start_idx = ct;
+       return KERN_SUCCESS;
+}
+
+static kern_return_t
+do_backtrace64(
+       task_t task,
+       thread_t thread,
+       x86_saved_state64_t *regs,
+       uint64_t *frames,
+       mach_msg_type_number_t *start_idx,
+       mach_msg_type_number_t max_idx,
+       boolean_t supervisor)
+{
+       uint64_t currPC = regs->isf.rip;
+       uint64_t currFP = regs->rbp;
+       uint64_t prevPC = 0ULL;
+       uint64_t prevFP = 0ULL;
+       uint64_t kernStackMin = (uint64_t)thread->kernel_stack;
+       uint64_t kernStackMax = (uint64_t)kernStackMin + kernel_stack_size;
+       mach_msg_type_number_t ct = *start_idx;
+       kern_return_t kr = KERN_FAILURE;
+
+       if (*start_idx >= max_idx) {
+               return KERN_RESOURCE_SHORTAGE;  // no frames traced
+       }
+       frames[ct++] = chudxnu_vm_unslide(currPC, supervisor);
+
+       // build a backtrace of this 32 bit state.
+       while (VALID_STACK_ADDRESS64(supervisor, currFP, kernStackMin, kernStackMax)) {
+               // this is the address where caller lives in the user thread
+               uint64_t caller = currFP + sizeof(uint64_t);
+
+               if (!currFP) {
+                       currPC = 0;
+                       break;
+               }
+
+               if (ct >= max_idx) {
+                       *start_idx = ct;
+                       return KERN_RESOURCE_SHORTAGE;
+               }
+
+               /* read our caller */
+               if (supervisor) {
+                       kr = chudxnu_kern_read(&currPC, (vm_offset_t)caller, sizeof(uint64_t));
+               } else {
+                       kr = chudxnu_task_read(task, &currPC, caller, sizeof(uint64_t));
+               }
+
+               if (kr != KERN_SUCCESS) {
+                       currPC = 0ULL;
+                       break;
+               }
+
+               /*
+                * retrive contents of the frame pointer and advance to the next stack
+                * frame if it's valid
+                */
+               prevFP = 0;
+               if (supervisor) {
+                       kr = chudxnu_kern_read(&prevFP, (vm_offset_t)currFP, sizeof(uint64_t));
+               } else {
+                       kr = chudxnu_task_read(task, &prevFP, currFP, sizeof(uint64_t));
+               }
+
+               if (VALID_STACK_ADDRESS64(supervisor, prevFP, kernStackMin, kernStackMax)) {
+                       frames[ct++] = chudxnu_vm_unslide(currPC, supervisor);
+                       prevPC = currPC;
+               }
+               if (prevFP < currFP) {
+                       break;
+               } else {
+                       currFP = prevFP;
+               }
+       }
+
+       *start_idx = ct;
+       return KERN_SUCCESS;
+}
+
+static kern_return_t
+chudxnu_thread_get_callstack64_internal(
+       thread_t                thread,
+       uint64_t                *callstack,
+       mach_msg_type_number_t  *count,
+       boolean_t               user_only,
+       boolean_t               kern_only)
+{
+       kern_return_t kr = KERN_FAILURE;
+       task_t task = thread->task;
+       uint64_t currPC = 0ULL;
+       boolean_t supervisor = FALSE;
+       mach_msg_type_number_t bufferIndex = 0;
+       mach_msg_type_number_t bufferMaxIndex = *count;
+       x86_saved_state_t *tagged_regs = NULL;          // kernel register state
+       x86_saved_state64_t *regs64 = NULL;
+       x86_saved_state32_t *regs32 = NULL;
+       x86_saved_state32_t *u_regs32 = NULL;
+       x86_saved_state64_t *u_regs64 = NULL;
+       struct x86_kernel_state *kregs = NULL;
+
+       if (ml_at_interrupt_context()) {
+               if (user_only) {
+                       /* can't backtrace user state on interrupt stack. */
+                       return KERN_FAILURE;
+               }
+
+               /* backtracing at interrupt context? */
+               if (thread == current_thread() && current_cpu_datap()->cpu_int_state) {
+                       /*
+                        * Locate the registers for the interrupted thread, assuming it is
+                        * current_thread().
+                        */
+                       tagged_regs = current_cpu_datap()->cpu_int_state;
+
+                       if (is_saved_state64(tagged_regs)) {
+                               /* 64 bit registers */
+                               regs64 = saved_state64(tagged_regs);
+                               supervisor = ((regs64->isf.cs & SEL_PL) != SEL_PL_U);
+                       } else {
+                               /* 32 bit registers */
+                               regs32 = saved_state32(tagged_regs);
+                               supervisor = ((regs32->cs & SEL_PL) != SEL_PL_U);
+                       }
+               }
+       }
+
+       if (!ml_at_interrupt_context() && kernel_task == task) {
+               if (!thread->kernel_stack) {
+                       return KERN_FAILURE;
+               }
+
+               // Kernel thread not at interrupt context
+               kregs = (struct x86_kernel_state *)NULL;
+
+               // nofault read of the thread->kernel_stack pointer
+               if (KERN_SUCCESS != chudxnu_kern_read(&kregs, (vm_offset_t)&(thread->kernel_stack), sizeof(void *))) {
+                       return KERN_FAILURE;
+               }
+
+               // Adjust to find the saved kernel state
+               kregs = STACK_IKS((vm_offset_t)(uintptr_t)kregs);
+
+               supervisor = TRUE;
+       } else if (!tagged_regs) {
+               /*
+                * not at interrupt context, or tracing a different thread than
+                * current_thread() at interrupt context
+                */
+               tagged_regs = USER_STATE(thread);
+               if (is_saved_state64(tagged_regs)) {
+                       /* 64 bit registers */
+                       regs64 = saved_state64(tagged_regs);
+                       supervisor = ((regs64->isf.cs & SEL_PL) != SEL_PL_U);
+               } else {
+                       /* 32 bit registers */
+                       regs32 = saved_state32(tagged_regs);
+                       supervisor = ((regs32->cs & SEL_PL) != SEL_PL_U);
+               }
+       }
+
+       *count = 0;
+
+       if (supervisor) {
+               // the caller only wants a user callstack.
+               if (user_only) {
+                       // bail - we've only got kernel state
+                       return KERN_FAILURE;
+               }
+       } else {
+               // regs32(64) is not in supervisor mode.
+               u_regs32 = regs32;
+               u_regs64 = regs64;
+               regs32 = NULL;
+               regs64 = NULL;
+       }
+
+       if (user_only) {
+               /* we only want to backtrace the user mode */
+               if (!(u_regs32 || u_regs64)) {
+                       /* no user state to look at */
+                       return KERN_FAILURE;
+               }
+       }
+
+       /*
+        * Order of preference for top of stack:
+        * 64 bit kernel state (not likely)
+        * 32 bit kernel state
+        * 64 bit user land state
+        * 32 bit user land state
+        */
+
+       if (kregs) {
+               /*
+                * nofault read of the registers from the kernel stack (as they can
+                * disappear on the fly).
+                */
+
+               if (KERN_SUCCESS != chudxnu_kern_read(&currPC, (vm_offset_t)&(kregs->k_rip), sizeof(uint64_t))) {
+                       return KERN_FAILURE;
+               }
+       } else if (regs64) {
+               currPC = regs64->isf.rip;
+       } else if (regs32) {
+               currPC = (uint64_t) regs32->eip;
+       } else if (u_regs64) {
+               currPC = u_regs64->isf.rip;
+       } else if (u_regs32) {
+               currPC = (uint64_t) u_regs32->eip;
+       }
+
+       if (!currPC) {
+               /* no top of the stack, bail out */
+               return KERN_FAILURE;
+       }
+
+       bufferIndex = 0;
+
+       if (bufferMaxIndex < 1) {
+               *count = 0;
+               return KERN_RESOURCE_SHORTAGE;
+       }
+
+       /* backtrace kernel */
+       if (kregs) {
+               addr64_t address = 0ULL;
+               size_t size = 0UL;
+
+               // do the backtrace
+               kr = do_kernel_backtrace(thread, kregs, callstack, &bufferIndex, bufferMaxIndex);
+
+               // and do a nofault read of (r|e)sp
+               uint64_t rsp = 0ULL;
+               size = sizeof(uint64_t);
+
+               if (KERN_SUCCESS != chudxnu_kern_read(&address, (vm_offset_t)&(kregs->k_rsp), size)) {
+                       address = 0ULL;
+               }
+
+               if (address && KERN_SUCCESS == chudxnu_kern_read(&rsp, (vm_offset_t)address, size) && bufferIndex < bufferMaxIndex) {
+                       callstack[bufferIndex++] = (uint64_t)rsp;
+               }
+       } else if (regs64) {
+               uint64_t rsp = 0ULL;
+
+               // backtrace the 64bit side.
+               kr = do_backtrace64(task, thread, regs64, callstack, &bufferIndex,
+                   bufferMaxIndex - 1, TRUE);
+
+               if (KERN_SUCCESS == chudxnu_kern_read(&rsp, (vm_offset_t) regs64->isf.rsp, sizeof(uint64_t)) &&
+                   bufferIndex < bufferMaxIndex) {
+                       callstack[bufferIndex++] = rsp;
+               }
+       } else if (regs32) {
+               uint32_t esp = 0UL;
+
+               // backtrace the 32bit side.
+               kr = do_backtrace32(task, thread, regs32, callstack, &bufferIndex,
+                   bufferMaxIndex - 1, TRUE);
+
+               if (KERN_SUCCESS == chudxnu_kern_read(&esp, (vm_offset_t) regs32->uesp, sizeof(uint32_t)) &&
+                   bufferIndex < bufferMaxIndex) {
+                       callstack[bufferIndex++] = (uint64_t) esp;
+               }
+       } else if (u_regs64 && !kern_only) {
+               /* backtrace user land */
+               uint64_t rsp = 0ULL;
+
+               kr = do_backtrace64(task, thread, u_regs64, callstack, &bufferIndex,
+                   bufferMaxIndex - 1, FALSE);
+
+               if (KERN_SUCCESS == chudxnu_task_read(task, &rsp, (addr64_t) u_regs64->isf.rsp, sizeof(uint64_t)) &&
+                   bufferIndex < bufferMaxIndex) {
+                       callstack[bufferIndex++] = rsp;
+               }
+       } else if (u_regs32 && !kern_only) {
+               uint32_t esp = 0UL;
+
+               kr = do_backtrace32(task, thread, u_regs32, callstack, &bufferIndex,
+                   bufferMaxIndex - 1, FALSE);
+
+               if (KERN_SUCCESS == chudxnu_task_read(task, &esp, (addr64_t) u_regs32->uesp, sizeof(uint32_t)) &&
+                   bufferIndex < bufferMaxIndex) {
+                       callstack[bufferIndex++] = (uint64_t) esp;
+               }
+       }
+
+       *count = bufferIndex;
+       return kr;
+}
+
+__private_extern__
+kern_return_t
+chudxnu_thread_get_callstack64_kperf(
+       thread_t                thread,
+       uint64_t                *callstack,
+       mach_msg_type_number_t  *count,
+       boolean_t               is_user)
+{
+       return chudxnu_thread_get_callstack64_internal(thread, callstack, count, is_user, !is_user);
+}
+#else /* !__arm__ && !__arm64__ && !__x86_64__ */
+#error kperf: unsupported architecture
+#endif /* !__arm__ && !__arm64__ && !__x86_64__ */