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Kernel: Correct Results in Condition Variables and Mutexes

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This commit is contained in:
Fernando Sahmkow 2019-10-07 18:57:13 -04:00 • committed by FernandoS27
parent 1ec1e81373
commit 44e09e5f21
3 changed files with 17 additions and 24 deletions
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27
src/core/hle/kernel/svc.cpp
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@ -1677,18 +1677,20 @@ static ResultCode SignalProcessWideKey(Core::System& system, VAddr condition_var
// Atomically read the value of the mutex.
u32 mutex_val = 0;
u32 update_val = 0;
const VAddr mutex_address = thread->GetMutexWaitAddress();
do {
monitor.SetExclusive(current_core, thread->GetMutexWaitAddress());
monitor.SetExclusive(current_core, mutex_address);
// If the mutex is not yet acquired, acquire it.
mutex_val = Memory::Read32(thread->GetMutexWaitAddress());
mutex_val = Memory::Read32(mutex_address);
if (mutex_val != 0) {
monitor.ClearExclusive();
break;
update_val = mutex_val | Mutex::MutexHasWaitersFlag;
} else {
update_val = thread->GetWaitHandle();
}
} while (!monitor.ExclusiveWrite32(current_core, thread->GetMutexWaitAddress(),
thread->GetWaitHandle()));
} while (!monitor.ExclusiveWrite32(current_core, mutex_address, update_val));
if (mutex_val == 0) {
// We were able to acquire the mutex, resume this thread.
ASSERT(thread->GetStatus() == ThreadStatus::WaitCondVar);
@ -1702,20 +1704,9 @@ static ResultCode SignalProcessWideKey(Core::System& system, VAddr condition_var
thread->SetLockOwner(nullptr);
thread->SetMutexWaitAddress(0);
thread->SetWaitHandle(0);
thread->SetWaitSynchronizationResult(RESULT_SUCCESS);
system.PrepareReschedule(thread->GetProcessorID());
} else {
// Atomically signal that the mutex now has a waiting thread.
do {
monitor.SetExclusive(current_core, thread->GetMutexWaitAddress());
// Ensure that the mutex value is still what we expect.
u32 value = Memory::Read32(thread->GetMutexWaitAddress());
// TODO(Subv): When this happens, the kernel just clears the exclusive state and
// retries the initial read for this thread.
ASSERT_MSG(mutex_val == value, "Unhandled synchronization primitive case");
} while (!monitor.ExclusiveWrite32(current_core, thread->GetMutexWaitAddress(),
mutex_val | Mutex::MutexHasWaitersFlag));
// The mutex is already owned by some other thread, make this thread wait on it.
const Handle owner_handle = static_cast<Handle>(mutex_val & Mutex::MutexOwnerMask);
const auto& handle_table = system.Kernel().CurrentProcess()->GetHandleTable();