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Fix OSX hardware exception and activation collision #1720

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Oct 8, 2015
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Fix OSX hardware exception and activation collision #1720

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80 changes: 47 additions & 33 deletions src/pal/src/exception/machexception.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1821,47 +1821,61 @@ PAL_ERROR InjectActivationInternal(CorUnix::CPalThread* pThread)
if (palError == NO_ERROR)
{
mach_port_t thread = pThread->GetMachPortSelf();
x86_thread_state64_t ThreadState;
mach_msg_type_number_t count = sizeof(ThreadState)/sizeof(natural_t);
mach_msg_type_number_t count;
kern_return_t MachRet;

x86_exception_state64_t ExceptionState;
count = x86_EXCEPTION_STATE64_COUNT;
MachRet = thread_get_state(thread,
x86_THREAD_STATE64,
(thread_state_t)&ThreadState,
x86_EXCEPTION_STATE64,
(thread_state_t)&ExceptionState,
&count);
_ASSERT_MSG(MachRet == KERN_SUCCESS, "thread_get_state\n");
_ASSERT_MSG(MachRet == KERN_SUCCESS, "thread_get_state for x86_EXCEPTION_STATE64\n");

if ((g_safeActivationCheckFunction != NULL) && g_safeActivationCheckFunction(ThreadState.__rip))
// Inject the activation only if the thread doesn't have a pending hardware exception
static const int MaxHardwareExceptionVector = 31;
if (ExceptionState.__trapno > MaxHardwareExceptionVector)
{
// TODO: it would be nice to preserve the red zone in case a jitter would want to use it
// Do we really care about unwinding through the wrapper?
size_t* sp = (size_t*)ThreadState.__rsp;
*(--sp) = ThreadState.__rip;
*(--sp) = ThreadState.__rbp;
size_t rbpAddress = (size_t)sp;
size_t contextAddress = (((size_t)sp) - sizeof(CONTEXT)) & ~15;
size_t returnAddressAddress = contextAddress - sizeof(size_t);
*(size_t*)(returnAddressAddress) = ActivationHandlerReturnOffset + (size_t)ActivationHandlerWrapper;

// Fill in the context in the helper frame with the full context of the suspended thread.
// The ActivationHandler will use the context to resume the execution of the thread
// after the activation function returns.
CONTEXT *pContext = (CONTEXT *)contextAddress;
pContext->ContextFlags = CONTEXT_FULL | CONTEXT_SEGMENTS;
MachRet = CONTEXT_GetThreadContextFromPort(thread, pContext);
_ASSERT_MSG(MachRet == KERN_SUCCESS, "CONTEXT_GetThreadContextFromPort\n");

// Make the instruction register point to ActivationHandler
ThreadState.__rip = (size_t)ActivationHandler;
ThreadState.__rsp = returnAddressAddress;
ThreadState.__rbp = rbpAddress;
ThreadState.__rdi = contextAddress;

MachRet = thread_set_state(thread,
x86_thread_state64_t ThreadState;
count = x86_THREAD_STATE64_COUNT;
MachRet = thread_get_state(thread,
x86_THREAD_STATE64,
(thread_state_t)&ThreadState,
count);
_ASSERT_MSG(MachRet == KERN_SUCCESS, "thread_set_state\n");
&count);
_ASSERT_MSG(MachRet == KERN_SUCCESS, "thread_get_state for x86_THREAD_STATE64\n");

if ((g_safeActivationCheckFunction != NULL) && g_safeActivationCheckFunction(ThreadState.__rip))
{
// TODO: it would be nice to preserve the red zone in case a jitter would want to use it
// Do we really care about unwinding through the wrapper?
size_t* sp = (size_t*)ThreadState.__rsp;
*(--sp) = ThreadState.__rip;
*(--sp) = ThreadState.__rbp;
size_t rbpAddress = (size_t)sp;
size_t contextAddress = (((size_t)sp) - sizeof(CONTEXT)) & ~15;
size_t returnAddressAddress = contextAddress - sizeof(size_t);
*(size_t*)(returnAddressAddress) = ActivationHandlerReturnOffset + (size_t)ActivationHandlerWrapper;

// Fill in the context in the helper frame with the full context of the suspended thread.
// The ActivationHandler will use the context to resume the execution of the thread
// after the activation function returns.
CONTEXT *pContext = (CONTEXT *)contextAddress;
pContext->ContextFlags = CONTEXT_FULL | CONTEXT_SEGMENTS;
MachRet = CONTEXT_GetThreadContextFromPort(thread, pContext);
_ASSERT_MSG(MachRet == KERN_SUCCESS, "CONTEXT_GetThreadContextFromPort\n");

// Make the instruction register point to ActivationHandler
ThreadState.__rip = (size_t)ActivationHandler;
ThreadState.__rsp = returnAddressAddress;
ThreadState.__rbp = rbpAddress;
ThreadState.__rdi = contextAddress;

MachRet = thread_set_state(thread,
x86_THREAD_STATE64,
(thread_state_t)&ThreadState,
count);
_ASSERT_MSG(MachRet == KERN_SUCCESS, "thread_set_state\n");
}
}

palError = pCurrentThread->suspensionInfo.InternalResumeThreadFromData(
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