Skip to content

Wow64: Spin loop on atomic with WFE #5660

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
lioncash merged 1 commit into from
Jul 8, 2026
Merged

Wow64: Spin loop on atomic with WFE #5660

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
25 changes: 25 additions & 0 deletions FEXCore/include/FEXCore/Utils/SpinWaitLock.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -144,6 +144,21 @@ static inline void WaitPred(T* Futex, T ComparisonValue) {
}
}

template<typename T, typename Pred>
static inline void WaitBitMaskPred(T* Futex, T BitMask, T ComparisonValue, Pred Predicate) {
auto AtomicFutex = std::atomic_ref<T>(*Futex);
T Result = AtomicFutex.load();

while (!Predicate(Result & BitMask, ComparisonValue)) {
Result = LoadExclusive(Futex);
if (Predicate(Result & BitMask, ComparisonValue)) {
return;
}

Result = WFELoadAtomic(Futex);
}
}

template<typename T, typename TT>
static inline bool Wait(T* Futex, TT ExpectedValue, const std::chrono::nanoseconds& Timeout) {
auto AtomicFutex = std::atomic_ref<T>(*Futex);
Expand Down Expand Up @@ -213,6 +228,16 @@ static inline void WaitPred(T* Futex, T ComparisonValue) {
}
}

template<typename T, typename Pred>
static inline void WaitBitMaskPred(T* Futex, T BitMask, T ComparisonValue, Pred Predicate) {
auto AtomicFutex = std::atomic_ref<T>(*Futex);
T Result = AtomicFutex.load();

while (!Predicate(Result & BitMask, ComparisonValue)) {
Result = AtomicFutex.load();
}
}

template<typename T, typename TT>
static inline bool Wait(T* Futex, TT ExpectedValue, const std::chrono::nanoseconds& Timeout) {
auto AtomicFutex = std::atomic_ref<T>(*Futex);
Expand Down
7 changes: 5 additions & 2 deletions Source/Windows/WOW64/Module.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -95,6 +95,10 @@ struct TLS {
return reinterpret_cast<std::atomic<uint32_t>&>(TEB->TlsSlots[FEXCore::ToUnderlying(Slot::CONTROL_WORD)]);
}

uint32_t* ControlWordAddress() const {
return reinterpret_cast<uint32_t*>(&TEB->TlsSlots[FEXCore::ToUnderlying(Slot::CONTROL_WORD)]);
}

CONTEXT*& EntryContext() const {
return reinterpret_cast<CONTEXT*&>(TEB->TlsSlots[FEXCore::ToUnderlying(Slot::ENTRY_CONTEXT)]);
}
Expand Down Expand Up @@ -822,8 +826,7 @@ NTSTATUS BTCpuSuspendLocalThread(HANDLE Thread, ULONG* Count) {
}

// Spin until the JIT is interrupted
while (TLS.ControlWord().load() & ControlBits::IN_JIT)
;
FEXCore::Utils::SpinWaitLock::WaitBitMaskPred(TLS.ControlWordAddress(), ControlBits::IN_JIT, 0U, std::equal_to<>());

// The JIT has now been interrupted and the context stored in the thread's CPU area is up-to-date
if (Err = NtSuspendThread(*ThreadDup, Count); Err) {
Expand Down
Loading