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Remove x86 OSX code (#36874)
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This removes x86 OSX code that was never used for .NET Core.
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@janvorli
janvorli authored May 22, 2020
1 parent 5118b4a commit 2e748bf
Showing 1 changed file with 0 additions and 125 deletions.
125 changes: 0 additions & 125 deletions src/coreclr/src/pal/src/exception/machexception.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -357,17 +357,11 @@ PAL_ERROR CorUnix::CPalThread::DisableMachExceptions()
return palError;
}

#if !defined(HOST_AMD64)
extern "C"
void PAL_DispatchException(PCONTEXT pContext, PEXCEPTION_RECORD pExRecord, MachExceptionInfo *pMachExceptionInfo)
#else // defined(HOST_AMD64)

// Since HijackFaultingThread pushed the context, exception record and info on the stack, we need to adjust the
// signature of PAL_DispatchException such that the corresponding arguments are considered to be on the stack
// per GCC64 calling convention rules. Hence, the first 6 dummy arguments (corresponding to RDI, RSI, RDX,RCX, R8, R9).
extern "C"
void PAL_DispatchException(DWORD64 dwRDI, DWORD64 dwRSI, DWORD64 dwRDX, DWORD64 dwRCX, DWORD64 dwR8, DWORD64 dwR9, PCONTEXT pContext, PEXCEPTION_RECORD pExRecord, MachExceptionInfo *pMachExceptionInfo)
#endif // !defined(HOST_AMD64)
{
CPalThread *pThread = InternalGetCurrentThread();

Expand Down Expand Up @@ -414,10 +408,8 @@ void PAL_DispatchException(DWORD64 dwRDI, DWORD64 dwRSI, DWORD64 dwRDX, DWORD64
}
}

#if defined(HOST_X86) || defined(HOST_AMD64)
extern "C" void PAL_DispatchExceptionWrapper();
extern "C" int PAL_DispatchExceptionReturnOffset;
#endif // HOST_X86 || HOST_AMD64

/*++
Function :
Expand Down Expand Up @@ -477,7 +469,6 @@ BuildExceptionRecord(
{
switch (exceptionInfo.Subcodes[0])
{
#if defined(HOST_X86) || defined(HOST_AMD64)
case EXC_I386_DIV:
exceptionCode = EXCEPTION_INT_DIVIDE_BY_ZERO;
break;
Expand All @@ -490,9 +481,6 @@ BuildExceptionRecord(
case EXC_I386_BOUND:
exceptionCode = EXCEPTION_ARRAY_BOUNDS_EXCEEDED;
break;
#else
#error Trap code to exception mapping not defined for this architecture
#endif
default:
exceptionCode = EXCEPTION_ILLEGAL_INSTRUCTION;
break;
Expand All @@ -501,16 +489,11 @@ BuildExceptionRecord(
break;

case EXC_SOFTWARE:
#if defined(HOST_X86) || defined(HOST_AMD64)
exceptionCode = EXCEPTION_ILLEGAL_INSTRUCTION;
break;
#else
#error Trap code to exception mapping not defined for this architecture
#endif

// Trace, breakpoint, etc. Details in subcode field.
case EXC_BREAKPOINT:
#if defined(HOST_X86) || defined(HOST_AMD64)
if (exceptionInfo.Subcodes[0] == EXC_I386_SGL)
{
exceptionCode = EXCEPTION_SINGLE_STEP;
Expand All @@ -519,9 +502,6 @@ BuildExceptionRecord(
{
exceptionCode = EXCEPTION_BREAKPOINT;
}
#else
#error Trap code to exception mapping not defined for this architecture
#endif
else
{
WARN("unexpected subcode %d for EXC_BREAKPOINT", exceptionInfo.Subcodes[0]);
Expand Down Expand Up @@ -615,17 +595,12 @@ HijackFaultingThread(
// Fill in the exception record from the exception info
BuildExceptionRecord(exceptionInfo, &exceptionRecord);

#ifdef HOST_X86
threadContext.ContextFlags = CONTEXT_FLOATING_POINT | CONTEXT_EXTENDED_REGISTERS;
#else
threadContext.ContextFlags = CONTEXT_FLOATING_POINT;
#endif
CONTEXT_GetThreadContextFromThreadState(x86_FLOAT_STATE, (thread_state_t)&exceptionInfo.FloatState, &threadContext);

threadContext.ContextFlags |= CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_SEGMENTS;
CONTEXT_GetThreadContextFromThreadState(x86_THREAD_STATE, (thread_state_t)&exceptionInfo.ThreadState, &threadContext);

#if defined(CORECLR) && (defined(HOST_X86) || defined(HOST_AMD64))
// For CoreCLR we look more deeply at access violations to determine whether they're the result of a stack
// overflow. If so we'll terminate the process immediately (the current default policy of the CoreCLR EE).
// Otherwise we'll either A/V ourselves trying to set up the SEH exception record and context on the
Expand Down Expand Up @@ -671,7 +646,6 @@ HijackFaultingThread(
// corrupted). Our managed jits always generate code which does this as does MSVC. GCC, however,
// does not do this by default. We have to explicitly provide the -fstack-check compiler option
// to enable the behavior.
#if (defined(HOST_X86) || defined(HOST_AMD64)) && defined(__APPLE__)
// Assume that AV isn't an SO to begin with.
bool fIsStackOverflow = false;

Expand All @@ -680,11 +654,7 @@ HijackFaultingThread(
// Calculate the page base addresses for the fault and the faulting thread's SP.
int cbPage = getpagesize();
char *pFaultPage = (char*)(exceptionRecord.ExceptionInformation[1] & ~(cbPage - 1));
#ifdef HOST_X86
char *pStackTopPage = (char*)(threadContext.Esp & ~(cbPage - 1));
#elif defined(HOST_AMD64)
char *pStackTopPage = (char*)(threadContext.Rsp & ~(cbPage - 1));
#endif

if (pFaultPage == pStackTopPage || pFaultPage == (pStackTopPage - cbPage))
{
Expand All @@ -699,36 +669,22 @@ HijackFaultingThread(
vm_size_t vm_size;
vm_region_flavor_t vm_flavor;
mach_msg_type_number_t infoCnt;
#ifdef HOST_64BIT
vm_region_basic_info_data_64_t info;
infoCnt = VM_REGION_BASIC_INFO_COUNT_64;
vm_flavor = VM_REGION_BASIC_INFO_64;
#else
vm_region_basic_info_data_t info;
infoCnt = VM_REGION_BASIC_INFO_COUNT;
vm_flavor = VM_REGION_BASIC_INFO;
#endif
mach_port_t object_name;

vm_address = (vm_address_t)(pFaultPage + cbPage);

#ifdef HOST_64BIT
machret = vm_region_64(
#else
machret = vm_region(
#endif
mach_task_self(),
&vm_address,
&vm_size,
vm_flavor,
(vm_region_info_t)&info,
&infoCnt,
&object_name);
#ifdef HOST_X86
CHECK_MACH("vm_region", machret);
#elif defined(HOST_AMD64)
CHECK_MACH("vm_region_64", machret);
#endif

// If vm_region updated the address we gave it then that address was not part of a region at all
// (and so this cannot be an SO). Otherwise check that the ESP lies in the region returned.
Expand All @@ -738,7 +694,6 @@ HijackFaultingThread(
fIsStackOverflow = true;
}

#if defined(HOST_AMD64)
if (!fIsStackOverflow)
{
// Check if we can read pointer sizeD bytes below the target thread's stack pointer.
Expand All @@ -755,79 +710,8 @@ HijackFaultingThread(
fIsStackOverflow = true;
}
}
#endif // HOST_AMD64
}
#else // (HOST_X86 || HOST_AMD64) && __APPLE__
#error Platform not supported for correct stack overflow handling
#endif // (HOST_X86 || HOST_AMD64) && __APPLE__
#endif // CORECLR && HOST_X86

#if defined(HOST_X86)
NONPAL_ASSERTE(exceptionInfo.ThreadState.tsh.flavor == x86_THREAD_STATE32);

// Make a copy of the thread state because the one in exceptionInfo needs to be preserved to restore
// the state if the exception is forwarded.
x86_thread_state32_t ts32 = exceptionInfo.ThreadState.uts.ts32;

// If we're in single step mode, disable it since we're going to call PAL_DispatchException
if (exceptionRecord.ExceptionCode == EXCEPTION_SINGLE_STEP)
{
ts32.eflags &= ~EFL_TF;
}

exceptionRecord.ExceptionFlags = EXCEPTION_IS_SIGNAL;
exceptionRecord.ExceptionRecord = NULL;
exceptionRecord.ExceptionAddress = (void *)ts32.eip;

void **FramePointer = (void **)ts32.esp;

*--FramePointer = (void *)ts32.eip;

// Construct a stack frame for a pretend activation of the function
// PAL_DispatchExceptionWrapper that serves only to make the stack
// correctly unwindable by the system exception unwinder.
// PAL_DispatchExceptionWrapper has an ebp frame, its local variables
// are the context and exception record, and it has just "called"
// PAL_DispatchException.
*--FramePointer = (void *)ts32.ebp;
ts32.ebp = (unsigned)FramePointer;

// Put the context on the stack
FramePointer = (void **)((ULONG_PTR)FramePointer - sizeof(CONTEXT));
// Make sure it's aligned - CONTEXT has 8-byte alignment
FramePointer = (void **)((ULONG_PTR)FramePointer - ((ULONG_PTR)FramePointer % 8));
CONTEXT *pContext = (CONTEXT *)FramePointer;
*pContext = threadContext;

// Put the exception record on the stack
FramePointer = (void **)((ULONG_PTR)FramePointer - sizeof(EXCEPTION_RECORD));
EXCEPTION_RECORD *pExceptionRecord = (EXCEPTION_RECORD *)FramePointer;
*pExceptionRecord = exceptionRecord;

FramePointer = (void **)((ULONG_PTR)FramePointer - sizeof(MachExceptionInfo));
MachExceptionInfo *pMachExceptionInfo = (MachExceptionInfo *)FramePointer;
*pMachExceptionInfo = exceptionInfo;

// Push arguments to PAL_DispatchException
FramePointer = (void **)((ULONG_PTR)FramePointer - 3 * sizeof(void *));

// Make sure it's aligned - ABI requires 16-byte alignment
FramePointer = (void **)((ULONG_PTR)FramePointer - ((ULONG_PTR)FramePointer % 16));
FramePointer[0] = pContext;
FramePointer[1] = pExceptionRecord;
FramePointer[2] = pMachExceptionInfo;

// Place the return address to right after the fake call in PAL_DispatchExceptionWrapper
FramePointer[-1] = (void *)((ULONG_PTR)PAL_DispatchExceptionWrapper + PAL_DispatchExceptionReturnOffset);

// Make the instruction register point to DispatchException
ts32.eip = (unsigned)PAL_DispatchException;
ts32.esp = (unsigned)&FramePointer[-1]; // skip return address

// Now set the thread state for the faulting thread so that PAL_DispatchException executes next
machret = thread_set_state(thread, x86_THREAD_STATE32, (thread_state_t)&ts32, x86_THREAD_STATE32_COUNT);
CHECK_MACH("thread_set_state(thread)", machret);
#elif defined(HOST_AMD64)
NONPAL_ASSERTE(exceptionInfo.ThreadState.tsh.flavor == x86_THREAD_STATE64);

// Make a copy of the thread state because the one in exceptionInfo needs to be preserved to restore
Expand Down Expand Up @@ -919,9 +803,6 @@ HijackFaultingThread(
// Now set the thread state for the faulting thread so that PAL_DispatchException executes next
machret = thread_set_state(thread, x86_THREAD_STATE64, (thread_state_t)&ts64, x86_THREAD_STATE64_COUNT);
CHECK_MACH("thread_set_state(thread)", machret);
#else
#error HijackFaultingThread not defined for this architecture
#endif
}

/*++
Expand Down Expand Up @@ -1234,13 +1115,7 @@ void MachExceptionInfo::RestoreState(mach_port_t thread)
{
if (Subcodes[0] == EXC_I386_BPT)
{
#ifdef HOST_X86
ThreadState.uts.ts32.eip--;
#elif defined(HOST_AMD64)
ThreadState.uts.ts64.__rip--;
#else
#error Platform not supported
#endif
}
}
kern_return_t machret = thread_set_state(thread, x86_THREAD_STATE, (thread_state_t)&ThreadState, x86_THREAD_STATE_COUNT);
Expand Down

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