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WOW64: Lock the JIT context and block suspend during context operations #5199

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Merged
Sonicadvance1 merged 1 commit into from
Jan 5, 2026
Merged

WOW64: Lock the JIT context and block suspend during context operations #5199

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32 changes: 22 additions & 10 deletions Source/Windows/WOW64/Module.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -360,6 +360,21 @@ void UnlockJITContext(TLS TLS) {
TLS.ControlWord().fetch_and(~ControlBits::IN_JIT, std::memory_order::relaxed);
}

class ScopedJITContextLock {
private:
TLS TLSData;

public:
ScopedJITContextLock(TLS TLSData)
: TLSData {TLSData} {
LockJITContext(TLSData);
}

~ScopedJITContextLock() {
UnlockJITContext(TLSData);
}
};

bool HandleSuspendInterrupt(TLS TLS, CONTEXT* Context, uint64_t FaultAddress) {
if (FaultAddress != reinterpret_cast<uint64_t>(&TLS.ThreadState()->InterruptFaultPage)) {
return false;
Expand Down Expand Up @@ -670,10 +685,9 @@ NTSTATUS BTCpuGetContext(HANDLE Thread, HANDLE Process, void* Unknown, WOW64_CON
return Err;
}

if (!(TLS.ControlWord().load(std::memory_order::relaxed) & ControlBits::WOW_CPU_AREA_DIRTY)) {
if (Err = Context::FlushThreadStateContext(*ThreadDup); Err) {
return Err;
}
Context::ScopedJITContextLock Lk {TLS};
if (Err = Context::FlushThreadStateContext(*ThreadDup); Err) {
return Err;
}

return RtlWow64GetThreadContext(*ThreadDup, Context);
Expand All @@ -693,10 +707,9 @@ NTSTATUS BTCpuSetContext(HANDLE Thread, HANDLE Process, void* Unknown, WOW64_CON
// Back-up the input context incase we've been passed the CPU area (the flush below would wipe it out otherwise)
WOW64_CONTEXT TmpContext = *Context;

if (!(TLS.ControlWord().load(std::memory_order::relaxed) & ControlBits::WOW_CPU_AREA_DIRTY)) {
if (Err = Context::FlushThreadStateContext(*ThreadDup); Err) {
return Err;
}
Context::ScopedJITContextLock Lk {TLS};
if (Err = Context::FlushThreadStateContext(*ThreadDup); Err) {
return Err;
}

// Merge the input context into the CPU area then pass the full context into the JIT
Expand Down Expand Up @@ -743,9 +756,8 @@ extern "C" void BTCpuSimulateImpl(CONTEXT* entry_context) {
TLS.EntryContext() = entry_context;
TLS.CachedCallRetSp() = TLS.ThreadState()->CurrentFrame->State.callret_sp;

Context::LockJITContext(TLS);
Context::ScopedJITContextLock Lk {TLS};
CTX->ExecuteThread(TLS.ThreadState());
Context::UnlockJITContext(TLS);
}

NTSTATUS BTCpuSuspendLocalThread(HANDLE Thread, ULONG* Count) {
Expand Down
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