6ddf8f34db
This was the result of a typo accidentally introduced in e51d715700a35a8f14e5b804b6f7553c9a40888b. This restores the previous correct behavior. The behavior with the reference was incorrect and would cause some games to fail to boot.
139 lines
4.5 KiB
C++
139 lines
4.5 KiB
C++
// Copyright 2014 Citra Emulator Project
|
|
// Licensed under GPLv2 or any later version
|
|
// Refer to the license.txt file included.
|
|
|
|
#include <map>
|
|
#include <utility>
|
|
#include <vector>
|
|
|
|
#include <boost/range/algorithm_ext/erase.hpp>
|
|
|
|
#include "common/assert.h"
|
|
#include "core/core.h"
|
|
#include "core/hle/kernel/errors.h"
|
|
#include "core/hle/kernel/handle_table.h"
|
|
#include "core/hle/kernel/mutex.h"
|
|
#include "core/hle/kernel/object.h"
|
|
#include "core/hle/kernel/thread.h"
|
|
#include "core/hle/result.h"
|
|
#include "core/memory.h"
|
|
|
|
namespace Kernel {
|
|
|
|
/// Returns the number of threads that are waiting for a mutex, and the highest priority one among
|
|
/// those.
|
|
static std::pair<SharedPtr<Thread>, u32> GetHighestPriorityMutexWaitingThread(
|
|
const SharedPtr<Thread>& current_thread, VAddr mutex_addr) {
|
|
|
|
SharedPtr<Thread> highest_priority_thread;
|
|
u32 num_waiters = 0;
|
|
|
|
for (const auto& thread : current_thread->GetMutexWaitingThreads()) {
|
|
if (thread->GetMutexWaitAddress() != mutex_addr)
|
|
continue;
|
|
|
|
ASSERT(thread->GetStatus() == ThreadStatus::WaitMutex);
|
|
|
|
++num_waiters;
|
|
if (highest_priority_thread == nullptr ||
|
|
thread->GetPriority() < highest_priority_thread->GetPriority()) {
|
|
highest_priority_thread = thread;
|
|
}
|
|
}
|
|
|
|
return {highest_priority_thread, num_waiters};
|
|
}
|
|
|
|
/// Update the mutex owner field of all threads waiting on the mutex to point to the new owner.
|
|
static void TransferMutexOwnership(VAddr mutex_addr, SharedPtr<Thread> current_thread,
|
|
SharedPtr<Thread> new_owner) {
|
|
const auto threads = current_thread->GetMutexWaitingThreads();
|
|
for (const auto& thread : threads) {
|
|
if (thread->GetMutexWaitAddress() != mutex_addr)
|
|
continue;
|
|
|
|
ASSERT(thread->GetLockOwner() == current_thread);
|
|
current_thread->RemoveMutexWaiter(thread);
|
|
if (new_owner != thread)
|
|
new_owner->AddMutexWaiter(thread);
|
|
}
|
|
}
|
|
|
|
ResultCode Mutex::TryAcquire(HandleTable& handle_table, VAddr address, Handle holding_thread_handle,
|
|
Handle requesting_thread_handle) {
|
|
// The mutex address must be 4-byte aligned
|
|
if ((address % sizeof(u32)) != 0) {
|
|
return ERR_INVALID_ADDRESS;
|
|
}
|
|
|
|
SharedPtr<Thread> holding_thread = handle_table.Get<Thread>(holding_thread_handle);
|
|
SharedPtr<Thread> requesting_thread = handle_table.Get<Thread>(requesting_thread_handle);
|
|
|
|
// TODO(Subv): It is currently unknown if it is possible to lock a mutex in behalf of another
|
|
// thread.
|
|
ASSERT(requesting_thread == GetCurrentThread());
|
|
|
|
u32 addr_value = Memory::Read32(address);
|
|
|
|
// If the mutex isn't being held, just return success.
|
|
if (addr_value != (holding_thread_handle | Mutex::MutexHasWaitersFlag)) {
|
|
return RESULT_SUCCESS;
|
|
}
|
|
|
|
if (holding_thread == nullptr)
|
|
return ERR_INVALID_HANDLE;
|
|
|
|
// Wait until the mutex is released
|
|
GetCurrentThread()->SetMutexWaitAddress(address);
|
|
GetCurrentThread()->SetWaitHandle(requesting_thread_handle);
|
|
|
|
GetCurrentThread()->SetStatus(ThreadStatus::WaitMutex);
|
|
GetCurrentThread()->InvalidateWakeupCallback();
|
|
|
|
// Update the lock holder thread's priority to prevent priority inversion.
|
|
holding_thread->AddMutexWaiter(GetCurrentThread());
|
|
|
|
Core::System::GetInstance().PrepareReschedule();
|
|
|
|
return RESULT_SUCCESS;
|
|
}
|
|
|
|
ResultCode Mutex::Release(VAddr address) {
|
|
// The mutex address must be 4-byte aligned
|
|
if ((address % sizeof(u32)) != 0) {
|
|
return ERR_INVALID_ADDRESS;
|
|
}
|
|
|
|
auto [thread, num_waiters] = GetHighestPriorityMutexWaitingThread(GetCurrentThread(), address);
|
|
|
|
// There are no more threads waiting for the mutex, release it completely.
|
|
if (thread == nullptr) {
|
|
Memory::Write32(address, 0);
|
|
return RESULT_SUCCESS;
|
|
}
|
|
|
|
// Transfer the ownership of the mutex from the previous owner to the new one.
|
|
TransferMutexOwnership(address, GetCurrentThread(), thread);
|
|
|
|
u32 mutex_value = thread->GetWaitHandle();
|
|
|
|
if (num_waiters >= 2) {
|
|
// Notify the guest that there are still some threads waiting for the mutex
|
|
mutex_value |= Mutex::MutexHasWaitersFlag;
|
|
}
|
|
|
|
// Grant the mutex to the next waiting thread and resume it.
|
|
Memory::Write32(address, mutex_value);
|
|
|
|
ASSERT(thread->GetStatus() == ThreadStatus::WaitMutex);
|
|
thread->ResumeFromWait();
|
|
|
|
thread->SetLockOwner(nullptr);
|
|
thread->SetCondVarWaitAddress(0);
|
|
thread->SetMutexWaitAddress(0);
|
|
thread->SetWaitHandle(0);
|
|
|
|
return RESULT_SUCCESS;
|
|
}
|
|
} // namespace Kernel
|