base/profiler/suspendable_thread_delegate_mac.cc

   1 // Copyright 2019 The Chromium Authors
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/profiler/suspendable_thread_delegate_mac.h"
   6
   7 #include <mach/mach.h>
   8 #include <mach/thread_act.h>
   9 #include <pthread.h>
  10
  11 #include <vector>
  12
  13 #include "base/apple/mach_logging.h"
  14 #include "base/check.h"
  15 #include "base/profiler/profile_builder.h"
  16 #include "build/build_config.h"
  17
  18 // IMPORTANT NOTE: Some functions within this implementation are invoked while
  19 // the target thread is suspended so it must not do any allocation from the
  20 // heap, including indirectly via use of DCHECK/CHECK or other logging
  21 // statements. Otherwise this code can deadlock on heap locks acquired by the
  22 // target thread before it was suspended. These functions are commented with "NO
  23 // HEAP ALLOCATIONS".
  24
  25 namespace base {
  26
  27 namespace {
  28
  29 #if defined(ARCH_CPU_X86_64)
  30 constexpr mach_msg_type_number_t kThreadStateCount = x86_THREAD_STATE64_COUNT;
  31 constexpr thread_state_flavor_t kThreadStateFlavor = x86_THREAD_STATE64;
  32 #elif defined(ARCH_CPU_ARM64)
  33 constexpr mach_msg_type_number_t kThreadStateCount = ARM_THREAD_STATE64_COUNT;
  34 constexpr thread_state_flavor_t kThreadStateFlavor = ARM_THREAD_STATE64;
  35 #endif
  36
  37 // Fills |state| with |target_thread|'s context. NO HEAP ALLOCATIONS.
  38 bool GetThreadContextImpl(thread_act_t target_thread, RegisterContext* state) {
  39   auto count = kThreadStateCount;
  40   return thread_get_state(target_thread, kThreadStateFlavor,
  41                           reinterpret_cast<thread_state_t>(state),
  42                           &count) == KERN_SUCCESS;
  43 }
  44
  45 }  // namespace
  46
  47 // ScopedSuspendThread --------------------------------------------------------
  48
  49 // NO HEAP ALLOCATIONS after thread_suspend.
  50 SuspendableThreadDelegateMac::ScopedSuspendThread::ScopedSuspendThread(
  51     mach_port_t thread_port)
  52     : thread_port_(thread_suspend(thread_port) == KERN_SUCCESS
  53                        ? thread_port
  54                        : MACH_PORT_NULL) {}
  55
  56 // NO HEAP ALLOCATIONS. The MACH_CHECK is OK because it provides a more noisy
  57 // failure mode than deadlocking.
  58 SuspendableThreadDelegateMac::ScopedSuspendThread::~ScopedSuspendThread() {
  59   if (!WasSuccessful())
  60     return;
  61
  62   kern_return_t kr = thread_resume(thread_port_);
  63   MACH_CHECK(kr == KERN_SUCCESS, kr) << "thread_resume";
  64 }
  65
  66 bool SuspendableThreadDelegateMac::ScopedSuspendThread::WasSuccessful() const {
  67   return thread_port_ != MACH_PORT_NULL;
  68 }
  69
  70 // SuspendableThreadDelegateMac -----------------------------------------------
  71
  72 SuspendableThreadDelegateMac::SuspendableThreadDelegateMac(
  73     SamplingProfilerThreadToken thread_token)
  74     : thread_port_(thread_token.id),
  75       thread_stack_base_address_(
  76           reinterpret_cast<uintptr_t>(pthread_get_stackaddr_np(
  77               pthread_from_mach_thread_np(thread_token.id)))) {
  78   // This class suspends threads, and those threads might be suspended in dyld.
  79   // Therefore, for all the system functions that might be linked in dynamically
  80   // that are used while threads are suspended, make calls to them to make sure
  81   // that they are linked up.
  82   RegisterContext thread_context;
  83   GetThreadContextImpl(thread_port_, &thread_context);
  84 }
  85
  86 SuspendableThreadDelegateMac::~SuspendableThreadDelegateMac() = default;
  87
  88 std::unique_ptr<SuspendableThreadDelegate::ScopedSuspendThread>
  89 SuspendableThreadDelegateMac::CreateScopedSuspendThread() {
  90   return std::make_unique<ScopedSuspendThread>(thread_port_);
  91 }
  92
  93 PlatformThreadId SuspendableThreadDelegateMac::GetThreadId() const {
  94   return thread_port_;
  95 }
  96
  97 // NO HEAP ALLOCATIONS.
  98 bool SuspendableThreadDelegateMac::GetThreadContext(
  99     RegisterContext* thread_context) {
 100   return GetThreadContextImpl(thread_port_, thread_context);
 101 }
 102
 103 // NO HEAP ALLOCATIONS.
 104 uintptr_t SuspendableThreadDelegateMac::GetStackBaseAddress() const {
 105   return thread_stack_base_address_;
 106 }
 107
 108 // NO HEAP ALLOCATIONS.
 109 bool SuspendableThreadDelegateMac::CanCopyStack(uintptr_t stack_pointer) {
 110   return true;
 111 }
 112
 113 std::vector<uintptr_t*> SuspendableThreadDelegateMac::GetRegistersToRewrite(
 114     RegisterContext* thread_context) {
 115 #if defined(ARCH_CPU_X86_64)
 116   return {
 117       &AsUintPtr(&thread_context->__rbx), &AsUintPtr(&thread_context->__rbp),
 118       &AsUintPtr(&thread_context->__rsp), &AsUintPtr(&thread_context->__r12),
 119       &AsUintPtr(&thread_context->__r13), &AsUintPtr(&thread_context->__r14),
 120       &AsUintPtr(&thread_context->__r15)};
 121 #elif defined(ARCH_CPU_ARM64)  // defined(ARCH_CPU_X86_64)
 122   return {
 123       &AsUintPtr(&thread_context->__fp),
 124       &AsUintPtr(&thread_context->__sp),
 125       &AsUintPtr(&thread_context->__x[19]),
 126       &AsUintPtr(&thread_context->__x[20]),
 127       &AsUintPtr(&thread_context->__x[21]),
 128       &AsUintPtr(&thread_context->__x[22]),
 129       &AsUintPtr(&thread_context->__x[23]),
 130       &AsUintPtr(&thread_context->__x[24]),
 131       &AsUintPtr(&thread_context->__x[25]),
 132       &AsUintPtr(&thread_context->__x[26]),
 133       &AsUintPtr(&thread_context->__x[27]),
 134       &AsUintPtr(&thread_context->__x[28]),
 135   };
 136 #endif                         // defined(ARCH_CPU_ARM64)
 137 }
 138
 139 }  // namespace base