NativeSignalHandler: Fix write flag (#4306)

* NativeSignalHandler: Fix write flag

* address comments
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merry 2023-01-19 00:13:17 +00:00 committed by GitHub
parent ae4324032a
commit 36d53819a4
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@ -109,12 +109,6 @@ namespace ARMeilleure.Signal
if (OperatingSystem.IsLinux() || OperatingSystem.IsMacOS())
{
// Unix siginfo struct locations.
// NOTE: These are incredibly likely to be different between kernel version and architectures.
config.StructAddressOffset = OperatingSystem.IsMacOS() ? 24 : 16; // si_addr
config.StructWriteOffset = 8; // si_code
_signalHandlerPtr = Marshal.GetFunctionPointerForDelegate(GenerateUnixSignalHandler(_handlerConfig));
if (customSignalHandlerFactory != null)
@ -251,18 +245,88 @@ namespace ARMeilleure.Signal
return context.Copy(inRegionLocal);
}
private static Operand GenerateUnixFaultAddress(EmitterContext context, Operand sigInfoPtr)
{
ulong structAddressOffset = OperatingSystem.IsMacOS() ? 24ul : 16ul; // si_addr
return context.Load(OperandType.I64, context.Add(sigInfoPtr, Const(structAddressOffset)));
}
private static Operand GenerateUnixWriteFlag(EmitterContext context, Operand ucontextPtr)
{
if (OperatingSystem.IsMacOS())
{
const ulong mcontextOffset = 48; // uc_mcontext
Operand ctxPtr = context.Load(OperandType.I64, context.Add(ucontextPtr, Const(mcontextOffset)));
if (RuntimeInformation.ProcessArchitecture == Architecture.Arm64)
{
const ulong esrOffset = 8; // __es.__esr
Operand esr = context.Load(OperandType.I64, context.Add(ctxPtr, Const(esrOffset)));
return context.BitwiseAnd(esr, Const(0x40ul));
}
if (RuntimeInformation.ProcessArchitecture == Architecture.X64)
{
const ulong errOffset = 4; // __es.__err
Operand err = context.Load(OperandType.I64, context.Add(ctxPtr, Const(errOffset)));
return context.BitwiseAnd(err, Const(2ul));
}
}
else if (OperatingSystem.IsLinux())
{
if (RuntimeInformation.ProcessArchitecture == Architecture.Arm64)
{
Operand auxPtr = context.AllocateLocal(OperandType.I64);
Operand loopLabel = Label();
Operand successLabel = Label();
const ulong auxOffset = 464; // uc_mcontext.__reserved
const uint esrMagic = 0x45535201;
context.Copy(auxPtr, context.Add(ucontextPtr, Const(auxOffset)));
context.MarkLabel(loopLabel);
// _aarch64_ctx::magic
Operand magic = context.Load(OperandType.I32, auxPtr);
// _aarch64_ctx::size
Operand size = context.Load(OperandType.I32, context.Add(auxPtr, Const(4ul)));
context.BranchIf(successLabel, magic, Const(esrMagic), Comparison.Equal);
context.Copy(auxPtr, context.Add(auxPtr, context.ZeroExtend32(OperandType.I64, size)));
context.Branch(loopLabel);
context.MarkLabel(successLabel);
// esr_context::esr
Operand esr = context.Load(OperandType.I64, context.Add(auxPtr, Const(8ul)));
return context.BitwiseAnd(esr, Const(0x40ul));
}
if (RuntimeInformation.ProcessArchitecture == Architecture.X64)
{
const int errOffset = 192; // uc_mcontext.gregs[REG_ERR]
Operand err = context.Load(OperandType.I64, context.Add(ucontextPtr, Const(errOffset)));
return context.BitwiseAnd(err, Const(2ul));
}
}
throw new PlatformNotSupportedException();
}
private static UnixExceptionHandler GenerateUnixSignalHandler(IntPtr signalStructPtr)
{
EmitterContext context = new EmitterContext();
// (int sig, SigInfo* sigInfo, void* ucontext)
Operand sigInfoPtr = context.LoadArgument(OperandType.I64, 1);
Operand ucontextPtr = context.LoadArgument(OperandType.I64, 2);
Operand structAddressOffset = context.Load(OperandType.I64, Const((ulong)signalStructPtr + StructAddressOffset));
Operand structWriteOffset = context.Load(OperandType.I64, Const((ulong)signalStructPtr + StructWriteOffset));
Operand faultAddress = context.Load(OperandType.I64, context.Add(sigInfoPtr, context.ZeroExtend32(OperandType.I64, structAddressOffset)));
Operand writeFlag = context.Load(OperandType.I64, context.Add(sigInfoPtr, context.ZeroExtend32(OperandType.I64, structWriteOffset)));
Operand faultAddress = GenerateUnixFaultAddress(context, sigInfoPtr);
Operand writeFlag = GenerateUnixWriteFlag(context, ucontextPtr);
Operand isWrite = context.ICompareNotEqual(writeFlag, Const(0L)); // Normalize to 0/1.