123 lines
3.6 KiB
C++
123 lines
3.6 KiB
C++
// Copyright 2014 Citra Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#include <map>
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#include <vector>
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#include <boost/range/algorithm_ext/erase.hpp>
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#include "common/assert.h"
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#include "core/core.h"
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#include "core/hle/kernel/errors.h"
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#include "core/hle/kernel/kernel.h"
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#include "core/hle/kernel/mutex.h"
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#include "core/hle/kernel/thread.h"
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namespace Kernel {
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void ReleaseThreadMutexes(Thread* thread) {
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for (auto& mtx : thread->held_mutexes) {
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mtx->lock_count = 0;
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mtx->holding_thread = nullptr;
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mtx->WakeupAllWaitingThreads();
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}
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thread->held_mutexes.clear();
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}
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Mutex::Mutex() {}
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Mutex::~Mutex() {}
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SharedPtr<Mutex> Mutex::Create(bool initial_locked, std::string name) {
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SharedPtr<Mutex> mutex(new Mutex);
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mutex->lock_count = 0;
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mutex->name = std::move(name);
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mutex->holding_thread = nullptr;
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// Acquire mutex with current thread if initialized as locked
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if (initial_locked)
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mutex->Acquire(GetCurrentThread());
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return mutex;
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}
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bool Mutex::ShouldWait(Thread* thread) const {
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return lock_count > 0 && thread != holding_thread;
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}
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void Mutex::Acquire(Thread* thread) {
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ASSERT_MSG(!ShouldWait(thread), "object unavailable!");
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// Actually "acquire" the mutex only if we don't already have it
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if (lock_count == 0) {
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priority = thread->current_priority;
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thread->held_mutexes.insert(this);
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holding_thread = thread;
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thread->UpdatePriority();
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Core::System::GetInstance().PrepareReschedule();
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}
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lock_count++;
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}
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ResultCode Mutex::Release(Thread* thread) {
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// We can only release the mutex if it's held by the calling thread.
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if (thread != holding_thread) {
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if (holding_thread) {
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LOG_ERROR(
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Kernel,
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"Tried to release a mutex (owned by thread id %u) from a different thread id %u",
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holding_thread->thread_id, thread->thread_id);
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}
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return ResultCode(ErrCodes::WrongLockingThread, ErrorModule::Kernel,
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ErrorSummary::InvalidArgument, ErrorLevel::Permanent);
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}
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// Note: It should not be possible for the situation where the mutex has a holding thread with a
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// zero lock count to occur. The real kernel still checks for this, so we do too.
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if (lock_count <= 0)
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return ResultCode(ErrorDescription::InvalidResultValue, ErrorModule::Kernel,
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ErrorSummary::InvalidState, ErrorLevel::Permanent);
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lock_count--;
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// Yield to the next thread only if we've fully released the mutex
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if (lock_count == 0) {
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holding_thread->held_mutexes.erase(this);
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holding_thread->UpdatePriority();
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holding_thread = nullptr;
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WakeupAllWaitingThreads();
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Core::System::GetInstance().PrepareReschedule();
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}
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return RESULT_SUCCESS;
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}
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void Mutex::AddWaitingThread(SharedPtr<Thread> thread) {
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WaitObject::AddWaitingThread(thread);
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thread->pending_mutexes.insert(this);
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UpdatePriority();
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}
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void Mutex::RemoveWaitingThread(Thread* thread) {
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WaitObject::RemoveWaitingThread(thread);
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thread->pending_mutexes.erase(this);
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UpdatePriority();
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}
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void Mutex::UpdatePriority() {
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if (!holding_thread)
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return;
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u32 best_priority = THREADPRIO_LOWEST;
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for (auto& waiter : GetWaitingThreads()) {
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if (waiter->current_priority < best_priority)
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best_priority = waiter->current_priority;
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}
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if (best_priority != priority) {
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priority = best_priority;
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holding_thread->UpdatePriority();
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}
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}
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} // namespace Kernel
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