mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
synced 2024-12-13 16:31:18 +01:00
69 lines
2.4 KiB
C++
69 lines
2.4 KiB
C++
/*
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* Copyright (c) Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <mesosphere/kern_common.hpp>
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#include <mesosphere/kern_select_cpu.hpp>
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#include <mesosphere/kern_k_current_context.hpp>
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#include <mesosphere/kern_k_scoped_lock.hpp>
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namespace ams::kern {
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class KLightLock {
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private:
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util::Atomic<uintptr_t> m_tag;
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public:
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constexpr KLightLock() : m_tag(0) { /* ... */ }
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void Lock() {
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MESOSPHERE_ASSERT_THIS();
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const uintptr_t cur_thread = reinterpret_cast<uintptr_t>(GetCurrentThreadPointer());
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while (true) {
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uintptr_t old_tag = m_tag.Load<std::memory_order_relaxed>();
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while (!m_tag.CompareExchangeWeak<std::memory_order_acquire>(old_tag, (old_tag == 0) ? cur_thread : (old_tag | 1))) {
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/* ... */
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}
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if (old_tag == 0 || this->LockSlowPath(old_tag | 1, cur_thread)) {
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break;
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}
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}
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}
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ALWAYS_INLINE void Unlock() {
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MESOSPHERE_ASSERT_THIS();
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const uintptr_t cur_thread = reinterpret_cast<uintptr_t>(GetCurrentThreadPointer());
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uintptr_t expected = cur_thread;
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if (!m_tag.CompareExchangeStrong<std::memory_order_release>(expected, 0)) {
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this->UnlockSlowPath(cur_thread);
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}
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}
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bool LockSlowPath(uintptr_t owner, uintptr_t cur_thread);
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void UnlockSlowPath(uintptr_t cur_thread);
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ALWAYS_INLINE bool IsLocked() const { return m_tag.Load() != 0; }
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ALWAYS_INLINE bool IsLockedByCurrentThread() const { return (m_tag.Load() | 0x1ul) == (reinterpret_cast<uintptr_t>(GetCurrentThreadPointer()) | 0x1ul); }
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};
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using KScopedLightLock = KScopedLock<KLightLock>;
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}
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