compiler-rt/lib/msan/msan_thread.cpp

   1
   2 #include "msan.h"
   3 #include "msan_thread.h"
   4 #include "msan_interface_internal.h"
   5
   6 #include "sanitizer_common/sanitizer_tls_get_addr.h"
   7
   8 namespace __msan {
   9
  10 MsanThread *MsanThread::Create(thread_callback_t start_routine,
  11                                void *arg) {
  12   uptr PageSize = GetPageSizeCached();
  13   uptr size = RoundUpTo(sizeof(MsanThread), PageSize);
  14   MsanThread *thread = (MsanThread*)MmapOrDie(size, __func__);
  15   thread->start_routine_ = start_routine;
  16   thread->arg_ = arg;
  17   thread->destructor_iterations_ = GetPthreadDestructorIterations();
  18
  19   return thread;
  20 }
  21
  22 void MsanThread::SetThreadStackAndTls() {
  23   uptr tls_size = 0;
  24   uptr stack_size = 0;
  25   GetThreadStackAndTls(IsMainThread(), &stack_.bottom, &stack_size, &tls_begin_,
  26                        &tls_size);
  27   stack_.top = stack_.bottom + stack_size;
  28   tls_end_ = tls_begin_ + tls_size;
  29
  30   int local;
  31   CHECK(AddrIsInStack((uptr)&local));
  32 }
  33
  34 void MsanThread::ClearShadowForThreadStackAndTLS() {
  35   __msan_unpoison((void *)stack_.bottom, stack_.top - stack_.bottom);
  36   if (tls_begin_ != tls_end_)
  37     __msan_unpoison((void *)tls_begin_, tls_end_ - tls_begin_);
  38   DTLS *dtls = DTLS_Get();
  39   CHECK_NE(dtls, 0);
  40   ForEachDVT(dtls, [](const DTLS::DTV &dtv, int id) {
  41     __msan_unpoison((void *)(dtv.beg), dtv.size);
  42   });
  43 }
  44
  45 void MsanThread::Init() {
  46   SetThreadStackAndTls();
  47   CHECK(MEM_IS_APP(stack_.bottom));
  48   CHECK(MEM_IS_APP(stack_.top - 1));
  49   ClearShadowForThreadStackAndTLS();
  50   malloc_storage().Init();
  51 }
  52
  53 void MsanThread::TSDDtor(void *tsd) {
  54   MsanThread *t = (MsanThread*)tsd;
  55   t->Destroy();
  56 }
  57
  58 void MsanThread::Destroy() {
  59   malloc_storage().CommitBack();
  60   // We also clear the shadow on thread destruction because
  61   // some code may still be executing in later TSD destructors
  62   // and we don't want it to have any poisoned stack.
  63   ClearShadowForThreadStackAndTLS();
  64   uptr size = RoundUpTo(sizeof(MsanThread), GetPageSizeCached());
  65   UnmapOrDie(this, size);
  66   DTLS_Destroy();
  67 }
  68
  69 thread_return_t MsanThread::ThreadStart() {
  70   if (!start_routine_) {
  71     // start_routine_ == 0 if we're on the main thread or on one of the
  72     // OS X libdispatch worker threads. But nobody is supposed to call
  73     // ThreadStart() for the worker threads.
  74     return 0;
  75   }
  76
  77   thread_return_t res = start_routine_(arg_);
  78
  79   return res;
  80 }
  81
  82 MsanThread::StackBounds MsanThread::GetStackBounds() const {
  83   if (!stack_switching_)
  84     return {stack_.bottom, stack_.top};
  85   const uptr cur_stack = GET_CURRENT_FRAME();
  86   // Note: need to check next stack first, because FinishSwitchFiber
  87   // may be in process of overwriting stack_.top/bottom_. But in such case
  88   // we are already on the next stack.
  89   if (cur_stack >= next_stack_.bottom && cur_stack < next_stack_.top)
  90     return {next_stack_.bottom, next_stack_.top};
  91   return {stack_.bottom, stack_.top};
  92 }
  93
  94 uptr MsanThread::stack_top() { return GetStackBounds().top; }
  95
  96 uptr MsanThread::stack_bottom() { return GetStackBounds().bottom; }
  97
  98 bool MsanThread::AddrIsInStack(uptr addr) {
  99   const auto bounds = GetStackBounds();
 100   return addr >= bounds.bottom && addr < bounds.top;
 101 }
 102
 103 void MsanThread::StartSwitchFiber(uptr bottom, uptr size) {
 104   CHECK(!stack_switching_);
 105   next_stack_.bottom = bottom;
 106   next_stack_.top = bottom + size;
 107   stack_switching_ = true;
 108 }
 109
 110 void MsanThread::FinishSwitchFiber(uptr *bottom_old, uptr *size_old) {
 111   CHECK(stack_switching_);
 112   if (bottom_old)
 113     *bottom_old = stack_.bottom;
 114   if (size_old)
 115     *size_old = stack_.top - stack_.bottom;
 116   stack_.bottom = next_stack_.bottom;
 117   stack_.top = next_stack_.top;
 118   stack_switching_ = false;
 119   next_stack_.top = 0;
 120   next_stack_.bottom = 0;
 121 }
 122
 123 } // namespace __msan