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// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <map>
#include <vector>
#include <boost/range/algorithm_ext/erase.hpp>
#include "common/assert.h"
#include "core/core.h"
#include "core/hle/kernel/handle_table.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/mutex.h"
#include "core/hle/kernel/object_address_table.h"
#include "core/hle/kernel/thread.h"
namespace Kernel {
void ReleaseThreadMutexes(Thread* thread) {
for (auto& mtx : thread->held_mutexes) {
mtx->lock_count = 0;
mtx->holding_thread = nullptr;
mtx->WakeupAllWaitingThreads();
}
thread->held_mutexes.clear();
}
Mutex::Mutex() {}
Mutex::~Mutex() {}
SharedPtr<Mutex> Mutex::Create(SharedPtr<Kernel::Thread> holding_thread, VAddr guest_addr,
std::string name) {
SharedPtr<Mutex> mutex(new Mutex);
mutex->lock_count = 0;
mutex->guest_addr = guest_addr;
mutex->name = std::move(name);
mutex->holding_thread = nullptr;
// If mutex was initialized with a holding thread, acquire it by the holding thread
if (holding_thread) {
mutex->Acquire(holding_thread.get());
}
// Mutexes are referenced by guest address, so track this in the kernel
g_object_address_table.Insert(guest_addr, mutex);
// Verify that the created mutex matches the guest state for the mutex
mutex->VerifyGuestState();
return mutex;
}
bool Mutex::ShouldWait(Thread* thread) const {
return lock_count > 0 && thread != holding_thread;
}
void Mutex::Acquire(Thread* thread) {
ASSERT_MSG(!ShouldWait(thread), "object unavailable!");
// Actually "acquire" the mutex only if we don't already have it
if (lock_count == 0) {
priority = thread->current_priority;
thread->held_mutexes.insert(this);
holding_thread = thread;
thread->UpdatePriority();
UpdateGuestState();
Core::System::GetInstance().PrepareReschedule();
}
lock_count++;
}
ResultCode Mutex::Release(Thread* thread) {
// We can only release the mutex if it's held by the calling thread.
if (thread != holding_thread) {
if (holding_thread) {
LOG_ERROR(
Kernel,
"Tried to release a mutex (owned by thread id %u) from a different thread id %u",
holding_thread->thread_id, thread->thread_id);
}
// TODO(bunnei): Use correct error code
return ResultCode(-1);
}
// Note: It should not be possible for the situation where the mutex has a holding thread with a
// zero lock count to occur. The real kernel still checks for this, so we do too.
if (lock_count <= 0) {
// TODO(bunnei): Use correct error code
return ResultCode(-1);
}
lock_count--;
// Yield to the next thread only if we've fully released the mutex
if (lock_count == 0) {
holding_thread->held_mutexes.erase(this);
holding_thread->UpdatePriority();
holding_thread = nullptr;
WakeupAllWaitingThreads();
UpdateGuestState();
Core::System::GetInstance().PrepareReschedule();
}
return RESULT_SUCCESS;
}
void Mutex::AddWaitingThread(SharedPtr<Thread> thread) {
WaitObject::AddWaitingThread(thread);
thread->pending_mutexes.insert(this);
UpdatePriority();
UpdateGuestState();
}
void Mutex::RemoveWaitingThread(Thread* thread) {
WaitObject::RemoveWaitingThread(thread);
thread->pending_mutexes.erase(this);
UpdatePriority();
UpdateGuestState();
}
void Mutex::UpdatePriority() {
if (!holding_thread)
return;
u32 best_priority = THREADPRIO_LOWEST;
for (auto& waiter : GetWaitingThreads()) {
if (waiter->current_priority < best_priority)
best_priority = waiter->current_priority;
}
if (best_priority != priority) {
priority = best_priority;
holding_thread->UpdatePriority();
}
}
void Mutex::UpdateGuestState() {
GuestState guest_state{Memory::Read32(guest_addr)};
guest_state.has_waiters.Assign(!GetWaitingThreads().empty());
guest_state.holding_thread_handle.Assign(holding_thread ? holding_thread->guest_handle : 0);
Memory::Write32(guest_addr, guest_state.raw);
}
void Mutex::VerifyGuestState() {
GuestState guest_state{Memory::Read32(guest_addr)};
ASSERT(guest_state.has_waiters == !GetWaitingThreads().empty());
ASSERT(guest_state.holding_thread_handle == holding_thread->guest_handle);
}
} // namespace Kernel
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