mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
synced 2024-12-22 02:12:06 +00:00
74 lines
2.7 KiB
C++
74 lines
2.7 KiB
C++
/*
|
|
* Copyright (c) 2018-2020 Atmosphère-NX
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms and conditions of the GNU General Public License,
|
|
* version 2, as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
* more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#pragma once
|
|
#include <mesosphere/kern_common.hpp>
|
|
#include <mesosphere/kern_select_cpu.hpp>
|
|
#include <mesosphere/kern_k_current_context.hpp>
|
|
#include <mesosphere/kern_k_scoped_lock.hpp>
|
|
|
|
namespace ams::kern {
|
|
|
|
class KLightLock {
|
|
private:
|
|
std::atomic<uintptr_t> tag;
|
|
public:
|
|
constexpr KLightLock() : tag(0) { /* ... */ }
|
|
|
|
void Lock() {
|
|
MESOSPHERE_ASSERT_THIS();
|
|
|
|
const uintptr_t cur_thread = reinterpret_cast<uintptr_t>(GetCurrentThreadPointer());
|
|
const uintptr_t cur_thread_tag = (cur_thread | 1);
|
|
|
|
while (true) {
|
|
uintptr_t old_tag = this->tag.load(std::memory_order_relaxed);
|
|
|
|
while (!this->tag.compare_exchange_weak(old_tag, (old_tag == 0) ? cur_thread : old_tag | 1, std::memory_order_acquire)) {
|
|
if ((old_tag | 1) == cur_thread_tag) {
|
|
return;
|
|
}
|
|
}
|
|
|
|
if ((old_tag == 0) || ((old_tag | 1) == cur_thread_tag)) {
|
|
break;
|
|
}
|
|
|
|
this->LockSlowPath(old_tag | 1, cur_thread);
|
|
}
|
|
}
|
|
|
|
void Unlock() {
|
|
MESOSPHERE_ASSERT_THIS();
|
|
|
|
const uintptr_t cur_thread = reinterpret_cast<uintptr_t>(GetCurrentThreadPointer());
|
|
uintptr_t expected = cur_thread;
|
|
do {
|
|
if (expected != cur_thread) {
|
|
return this->UnlockSlowPath(cur_thread);
|
|
}
|
|
} while (!this->tag.compare_exchange_weak(expected, 0, std::memory_order_release));
|
|
}
|
|
|
|
void LockSlowPath(uintptr_t owner, uintptr_t cur_thread);
|
|
void UnlockSlowPath(uintptr_t cur_thread);
|
|
|
|
bool IsLocked() const { return this->tag != 0; }
|
|
bool IsLockedByCurrentThread() const { return (this->tag | 0x1ul) == (reinterpret_cast<uintptr_t>(GetCurrentThreadPointer()) | 0x1ul); }
|
|
};
|
|
|
|
using KScopedLightLock = KScopedLock<KLightLock>;
|
|
|
|
}
|