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Kernel: Actually wake up the requested number of threads in Semaphore::Release.

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Also properly keep track of data in guest memory, this fixes managing the semaphore from userland.

It was found that Semaphores are actually Condition Variables, with Release(1) and Release(-1) being equivalent to notify_one and notify_all. We should change the name of the class to reflect this.
This commit is contained in:
Subv 2018-01-08 14:14:30 -05:00 • committed by bunnei
parent 2ca36ac394
commit 96e2acfa8f
4 changed files with 18 additions and 21 deletions
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23
src/core/hle/kernel/semaphore.cpp
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@ -18,9 +18,6 @@ ResultVal<SharedPtr<Semaphore>> Semaphore::Create(VAddr guest_addr, VAddr mutex_
std::string name) {
SharedPtr<Semaphore> semaphore(new Semaphore);
// When the semaphore is created, some slots are reserved for other threads,
// and the rest is reserved for the caller thread;
semaphore->available_count = Memory::Read32(guest_addr);
semaphore->name = std::move(name);
semaphore->guest_addr = guest_addr;
semaphore->mutex_addr = mutex_addr;
@ -32,34 +29,36 @@ ResultVal<SharedPtr<Semaphore>> Semaphore::Create(VAddr guest_addr, VAddr mutex_
}
bool Semaphore::ShouldWait(Thread* thread) const {
return available_count <= 0;
return GetAvailableCount() <= 0;
}
void Semaphore::Acquire(Thread* thread) {
if (available_count <= 0)
if (GetAvailableCount() <= 0)
return;
--available_count;
UpdateGuestState();
SetAvailableCount(GetAvailableCount() - 1);
}
ResultCode Semaphore::Release(s32 target) {
++available_count;
UpdateGuestState();
if (target == -1) {
// When -1, wake up all waiting threads
SetAvailableCount(GetWaitingThreads().size());
WakeupAllWaitingThreads();
} else {
// Otherwise, wake up just a single thread
SetAvailableCount(target);
WakeupWaitingThread(GetHighestPriorityReadyThread());
}
return RESULT_SUCCESS;
}
void Semaphore::UpdateGuestState() {
Memory::Write32(guest_addr, available_count);
s32 Semaphore::GetAvailableCount() const {
return Memory::Read32(guest_addr);
}
void Semaphore::SetAvailableCount(s32 value) const {
Memory::Write32(guest_addr, value);
}
} // namespace Kernel