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// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <atomic>
#include "common/assert.h"
#include "core/hle/kernel/k_interrupt_manager.h"
#include "core/hle/kernel/k_spin_lock.h"
#include "core/hle/kernel/k_thread.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/physical_core.h"
namespace Kernel {
class KernelCore;
template <typename SchedulerType>
class KAbstractSchedulerLock {
public:
explicit KAbstractSchedulerLock(KernelCore& kernel_) : kernel{kernel_} {}
bool IsLockedByCurrentThread() const {
return owner_thread == GetCurrentThreadPointer(kernel);
}
void Lock() {
// If we are shutting down the kernel, none of this is relevant anymore.
if (kernel.IsShuttingDown()) {
return;
}
if (IsLockedByCurrentThread()) {
// If we already own the lock, we can just increment the count.
ASSERT(lock_count > 0);
lock_count++;
} else {
// Otherwise, we want to disable scheduling and acquire the spinlock.
SchedulerType::DisableScheduling(kernel);
spin_lock.Lock();
// For debug, ensure that our state is valid.
ASSERT(lock_count == 0);
ASSERT(owner_thread == nullptr);
// Increment count, take ownership.
lock_count = 1;
owner_thread = GetCurrentThreadPointer(kernel);
}
}
void Unlock() {
// If we are shutting down the kernel, none of this is relevant anymore.
if (kernel.IsShuttingDown()) {
return;
}
ASSERT(IsLockedByCurrentThread());
ASSERT(lock_count > 0);
// Release an instance of the lock.
if ((--lock_count) == 0) {
// Perform a memory barrier here.
std::atomic_thread_fence(std::memory_order_seq_cst);
// We're no longer going to hold the lock. Take note of what cores need scheduling.
const u64 cores_needing_scheduling =
SchedulerType::UpdateHighestPriorityThreads(kernel);
// Note that we no longer hold the lock, and unlock the spinlock.
owner_thread = nullptr;
spin_lock.Unlock();
// Enable scheduling, and perform a rescheduling operation.
SchedulerType::EnableScheduling(kernel, cores_needing_scheduling);
}
}
private:
KernelCore& kernel;
KAlignedSpinLock spin_lock{};
s32 lock_count{};
std::atomic<KThread*> owner_thread{};
};
} // namespace Kernel
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