Merge pull request #5197 from bylaws/rwxp5

Windows: Improve handling of RWX memory

Source/Windows/WOW64/Module.cpp

@@ -107,6 +107,10 @@ struct TLS {
   }
 };
 
+struct FrontendThreadData {
+  bool InLockedRWXRead {};
+};
+
 class WowSyscallHandler;
 
 namespace {
@@ -142,6 +146,10 @@ TLS GetTLS() {
   return TLS {NtCurrentTeb()};
 }
 
+FrontendThreadData* GetFrontendThreadData(FEXCore::Core::InternalThreadState* Thread) {
+  return static_cast<FrontendThreadData*>(Thread->FrontendPtr);
+}
+
 uint64_t GetWowTEB(void* TEB) {
   static constexpr size_t WowTEBOffsetMemberOffset {0x180c};
   return static_cast<uint64_t>(
@@ -610,6 +618,8 @@ void BTCpuThreadInit() {
   TLS.ThreadState() = Thread;
   TLS.ControlWord().fetch_or(ControlBits::WOW_CPU_AREA_DIRTY, std::memory_order::relaxed);
 
+  Thread->FrontendPtr = new FrontendThreadData();
+
   auto ThreadTID = GetCurrentThreadId();
   Threads.emplace(ThreadTID, Thread);
   if (StatAllocHandler) {
@@ -656,6 +666,8 @@ void BTCpuThreadTerm(HANDLE Thread, LONG ExitCode) {
   }
   auto ThreadState = TLS.ThreadState();
 
+  delete GetFrontendThreadData(ThreadState);
+
   // GDT and LDT are mirrored, only free one.
   delete[] ThreadState->CurrentFrame->State.segment_arrays[FEXCore::Core::CPUState::SEGMENT_ARRAY_INDEX_GDT];
 
@@ -1004,7 +1016,25 @@ void BTCpuNotifyUnmapViewOfSection(void* Address, BOOL After, ULONG Status) {
   }
 }
 
-void BTCpuNotifyReadFile(HANDLE Handle, void* Address, SIZE_T Size, BOOL After, NTSTATUS Status) {}
+void BTCpuNotifyReadFile(HANDLE Handle, void* Address, SIZE_T Size, BOOL After, NTSTATUS Status) {
+  auto& InLockedRWXRead = GetFrontendThreadData(GetTLS().ThreadState())->InLockedRWXRead;
+  if (!After) {
+    ThreadCreationMutex.lock();
+    CTX->GetCodeInvalidationMutex().lock();
+    if (InvalidationTracker->BeginUntrackedWriteLocked(reinterpret_cast<uint64_t>(Address), static_cast<uint64_t>(Size))) {
+      InLockedRWXRead = true;
+    } else {
+      CTX->GetCodeInvalidationMutex().unlock();
+      ThreadCreationMutex.unlock();
+    }
+  } else {
+    if (InLockedRWXRead) {
+      InLockedRWXRead = false;
+      CTX->GetCodeInvalidationMutex().unlock();
+      ThreadCreationMutex.unlock();
+    }
+  }
+}
 
 BOOLEAN WINAPI BTCpuIsProcessorFeaturePresent(UINT Feature) {
   return CPUFeatures->IsFeaturePresent(Feature) ? TRUE : FALSE;