Ryujinx/ARMeilleure/Signal/NativeSignalHandler.cs
merry 36d53819a4
NativeSignalHandler: Fix write flag (#4306)
* NativeSignalHandler: Fix write flag

* address comments
2023-01-19 00:13:17 +00:00

423 lines
17 KiB
C#

using ARMeilleure.IntermediateRepresentation;
using ARMeilleure.Memory;
using ARMeilleure.Translation;
using ARMeilleure.Translation.Cache;
using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using static ARMeilleure.IntermediateRepresentation.Operand.Factory;
namespace ARMeilleure.Signal
{
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct SignalHandlerRange
{
public int IsActive;
public nuint RangeAddress;
public nuint RangeEndAddress;
public IntPtr ActionPointer;
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct SignalHandlerConfig
{
/// <summary>
/// The byte offset of the faulting address in the SigInfo or ExceptionRecord struct.
/// </summary>
public int StructAddressOffset;
/// <summary>
/// The byte offset of the write flag in the SigInfo or ExceptionRecord struct.
/// </summary>
public int StructWriteOffset;
/// <summary>
/// The sigaction handler that was registered before this one. (unix only)
/// </summary>
public nuint UnixOldSigaction;
/// <summary>
/// The type of the previous sigaction. True for the 3 argument variant. (unix only)
/// </summary>
public int UnixOldSigaction3Arg;
public SignalHandlerRange Range0;
public SignalHandlerRange Range1;
public SignalHandlerRange Range2;
public SignalHandlerRange Range3;
public SignalHandlerRange Range4;
public SignalHandlerRange Range5;
public SignalHandlerRange Range6;
public SignalHandlerRange Range7;
}
public static class NativeSignalHandler
{
private delegate void UnixExceptionHandler(int sig, IntPtr info, IntPtr ucontext);
[UnmanagedFunctionPointer(CallingConvention.Winapi)]
private delegate int VectoredExceptionHandler(IntPtr exceptionInfo);
private const int MaxTrackedRanges = 8;
private const int StructAddressOffset = 0;
private const int StructWriteOffset = 4;
private const int UnixOldSigaction = 8;
private const int UnixOldSigaction3Arg = 16;
private const int RangeOffset = 20;
private const int EXCEPTION_CONTINUE_SEARCH = 0;
private const int EXCEPTION_CONTINUE_EXECUTION = -1;
private const uint EXCEPTION_ACCESS_VIOLATION = 0xc0000005;
private static ulong _pageSize;
private static ulong _pageMask;
private static IntPtr _handlerConfig;
private static IntPtr _signalHandlerPtr;
private static IntPtr _signalHandlerHandle;
private static readonly object _lock = new object();
private static bool _initialized;
static NativeSignalHandler()
{
_handlerConfig = Marshal.AllocHGlobal(Unsafe.SizeOf<SignalHandlerConfig>());
ref SignalHandlerConfig config = ref GetConfigRef();
config = new SignalHandlerConfig();
}
public static void Initialize(IJitMemoryAllocator allocator)
{
JitCache.Initialize(allocator);
}
public static void InitializeSignalHandler(ulong pageSize, Func<IntPtr, IntPtr, IntPtr> customSignalHandlerFactory = null)
{
if (_initialized) return;
lock (_lock)
{
if (_initialized) return;
_pageSize = pageSize;
_pageMask = pageSize - 1;
ref SignalHandlerConfig config = ref GetConfigRef();
if (OperatingSystem.IsLinux() || OperatingSystem.IsMacOS())
{
_signalHandlerPtr = Marshal.GetFunctionPointerForDelegate(GenerateUnixSignalHandler(_handlerConfig));
if (customSignalHandlerFactory != null)
{
_signalHandlerPtr = customSignalHandlerFactory(UnixSignalHandlerRegistration.GetSegfaultExceptionHandler().sa_handler, _signalHandlerPtr);
}
var old = UnixSignalHandlerRegistration.RegisterExceptionHandler(_signalHandlerPtr);
config.UnixOldSigaction = (nuint)(ulong)old.sa_handler;
config.UnixOldSigaction3Arg = old.sa_flags & 4;
}
else
{
config.StructAddressOffset = 40; // ExceptionInformation1
config.StructWriteOffset = 32; // ExceptionInformation0
_signalHandlerPtr = Marshal.GetFunctionPointerForDelegate(GenerateWindowsSignalHandler(_handlerConfig));
if (customSignalHandlerFactory != null)
{
_signalHandlerPtr = customSignalHandlerFactory(IntPtr.Zero, _signalHandlerPtr);
}
_signalHandlerHandle = WindowsSignalHandlerRegistration.RegisterExceptionHandler(_signalHandlerPtr);
}
_initialized = true;
}
}
private static unsafe ref SignalHandlerConfig GetConfigRef()
{
return ref Unsafe.AsRef<SignalHandlerConfig>((void*)_handlerConfig);
}
public static unsafe bool AddTrackedRegion(nuint address, nuint endAddress, IntPtr action)
{
var ranges = &((SignalHandlerConfig*)_handlerConfig)->Range0;
for (int i = 0; i < MaxTrackedRanges; i++)
{
if (ranges[i].IsActive == 0)
{
ranges[i].RangeAddress = address;
ranges[i].RangeEndAddress = endAddress;
ranges[i].ActionPointer = action;
ranges[i].IsActive = 1;
return true;
}
}
return false;
}
public static unsafe bool RemoveTrackedRegion(nuint address)
{
var ranges = &((SignalHandlerConfig*)_handlerConfig)->Range0;
for (int i = 0; i < MaxTrackedRanges; i++)
{
if (ranges[i].IsActive == 1 && ranges[i].RangeAddress == address)
{
ranges[i].IsActive = 0;
return true;
}
}
return false;
}
private static Operand EmitGenericRegionCheck(EmitterContext context, IntPtr signalStructPtr, Operand faultAddress, Operand isWrite)
{
Operand inRegionLocal = context.AllocateLocal(OperandType.I32);
context.Copy(inRegionLocal, Const(0));
Operand endLabel = Label();
for (int i = 0; i < MaxTrackedRanges; i++)
{
ulong rangeBaseOffset = (ulong)(RangeOffset + i * Unsafe.SizeOf<SignalHandlerRange>());
Operand nextLabel = Label();
Operand isActive = context.Load(OperandType.I32, Const((ulong)signalStructPtr + rangeBaseOffset));
context.BranchIfFalse(nextLabel, isActive);
Operand rangeAddress = context.Load(OperandType.I64, Const((ulong)signalStructPtr + rangeBaseOffset + 4));
Operand rangeEndAddress = context.Load(OperandType.I64, Const((ulong)signalStructPtr + rangeBaseOffset + 12));
// Is the fault address within this tracked region?
Operand inRange = context.BitwiseAnd(
context.ICompare(faultAddress, rangeAddress, Comparison.GreaterOrEqualUI),
context.ICompare(faultAddress, rangeEndAddress, Comparison.LessUI)
);
// Only call tracking if in range.
context.BranchIfFalse(nextLabel, inRange, BasicBlockFrequency.Cold);
Operand offset = context.BitwiseAnd(context.Subtract(faultAddress, rangeAddress), Const(~_pageMask));
// Call the tracking action, with the pointer's relative offset to the base address.
Operand trackingActionPtr = context.Load(OperandType.I64, Const((ulong)signalStructPtr + rangeBaseOffset + 20));
context.Copy(inRegionLocal, Const(0));
Operand skipActionLabel = Label();
// Tracking action should be non-null to call it, otherwise assume false return.
context.BranchIfFalse(skipActionLabel, trackingActionPtr);
Operand result = context.Call(trackingActionPtr, OperandType.I32, offset, Const(_pageSize), isWrite, Const(0));
context.Copy(inRegionLocal, result);
context.MarkLabel(skipActionLabel);
// If the tracking action returns false or does not exist, it might be an invalid access due to a partial overlap on Windows.
if (OperatingSystem.IsWindows())
{
context.BranchIfTrue(endLabel, inRegionLocal);
context.Copy(inRegionLocal, WindowsPartialUnmapHandler.EmitRetryFromAccessViolation(context));
}
context.Branch(endLabel);
context.MarkLabel(nextLabel);
}
context.MarkLabel(endLabel);
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 faultAddress = GenerateUnixFaultAddress(context, sigInfoPtr);
Operand writeFlag = GenerateUnixWriteFlag(context, ucontextPtr);
Operand isWrite = context.ICompareNotEqual(writeFlag, Const(0L)); // Normalize to 0/1.
Operand isInRegion = EmitGenericRegionCheck(context, signalStructPtr, faultAddress, isWrite);
Operand endLabel = Label();
context.BranchIfTrue(endLabel, isInRegion);
Operand unixOldSigaction = context.Load(OperandType.I64, Const((ulong)signalStructPtr + UnixOldSigaction));
Operand unixOldSigaction3Arg = context.Load(OperandType.I64, Const((ulong)signalStructPtr + UnixOldSigaction3Arg));
Operand threeArgLabel = Label();
context.BranchIfTrue(threeArgLabel, unixOldSigaction3Arg);
context.Call(unixOldSigaction, OperandType.None, context.LoadArgument(OperandType.I32, 0));
context.Branch(endLabel);
context.MarkLabel(threeArgLabel);
context.Call(unixOldSigaction,
OperandType.None,
context.LoadArgument(OperandType.I32, 0),
sigInfoPtr,
context.LoadArgument(OperandType.I64, 2)
);
context.MarkLabel(endLabel);
context.Return();
ControlFlowGraph cfg = context.GetControlFlowGraph();
OperandType[] argTypes = new OperandType[] { OperandType.I32, OperandType.I64, OperandType.I64 };
return Compiler.Compile(cfg, argTypes, OperandType.None, CompilerOptions.HighCq, RuntimeInformation.ProcessArchitecture).Map<UnixExceptionHandler>();
}
private static VectoredExceptionHandler GenerateWindowsSignalHandler(IntPtr signalStructPtr)
{
EmitterContext context = new EmitterContext();
// (ExceptionPointers* exceptionInfo)
Operand exceptionInfoPtr = context.LoadArgument(OperandType.I64, 0);
Operand exceptionRecordPtr = context.Load(OperandType.I64, exceptionInfoPtr);
// First thing's first - this catches a number of exceptions, but we only want access violations.
Operand validExceptionLabel = Label();
Operand exceptionCode = context.Load(OperandType.I32, exceptionRecordPtr);
context.BranchIf(validExceptionLabel, exceptionCode, Const(EXCEPTION_ACCESS_VIOLATION), Comparison.Equal);
context.Return(Const(EXCEPTION_CONTINUE_SEARCH)); // Don't handle this one.
context.MarkLabel(validExceptionLabel);
// Next, read the address of the invalid access, and whether it is a write or not.
Operand structAddressOffset = context.Load(OperandType.I32, Const((ulong)signalStructPtr + StructAddressOffset));
Operand structWriteOffset = context.Load(OperandType.I32, Const((ulong)signalStructPtr + StructWriteOffset));
Operand faultAddress = context.Load(OperandType.I64, context.Add(exceptionRecordPtr, context.ZeroExtend32(OperandType.I64, structAddressOffset)));
Operand writeFlag = context.Load(OperandType.I64, context.Add(exceptionRecordPtr, context.ZeroExtend32(OperandType.I64, structWriteOffset)));
Operand isWrite = context.ICompareNotEqual(writeFlag, Const(0L)); // Normalize to 0/1.
Operand isInRegion = EmitGenericRegionCheck(context, signalStructPtr, faultAddress, isWrite);
Operand endLabel = Label();
// If the region check result is false, then run the next vectored exception handler.
context.BranchIfTrue(endLabel, isInRegion);
context.Return(Const(EXCEPTION_CONTINUE_SEARCH));
context.MarkLabel(endLabel);
// Otherwise, return to execution.
context.Return(Const(EXCEPTION_CONTINUE_EXECUTION));
// Compile and return the function.
ControlFlowGraph cfg = context.GetControlFlowGraph();
OperandType[] argTypes = new OperandType[] { OperandType.I64 };
return Compiler.Compile(cfg, argTypes, OperandType.I32, CompilerOptions.HighCq, RuntimeInformation.ProcessArchitecture).Map<VectoredExceptionHandler>();
}
}
}