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https://github.com/SerenityOS/serenity
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1d621ab172
This adds support for FUTEX_WAKE_OP, FUTEX_WAIT_BITSET, FUTEX_WAKE_BITSET, FUTEX_REQUEUE, and FUTEX_CMP_REQUEUE, as well well as global and private futex and absolute/relative timeouts against the appropriate clock. This also changes the implementation so that kernel resources are only used when a thread is blocked on a futex. Global futexes are implemented as offsets in VMObjects, so that different processes can share a futex against the same VMObject despite potentially being mapped at different virtual addresses.
68 lines
2.5 KiB
C++
68 lines
2.5 KiB
C++
/*
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* Copyright (c) 2020, The SerenityOS developers.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <AK/Atomic.h>
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#include <AK/RefCounted.h>
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#include <Kernel/SpinLock.h>
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#include <Kernel/Thread.h>
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#include <Kernel/VM/VMObject.h>
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namespace Kernel {
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class FutexQueue : public Thread::BlockCondition
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, public RefCounted<FutexQueue>
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, public VMObjectDeletedHandler {
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public:
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FutexQueue(FlatPtr user_address_or_offset, VMObject* vmobject = nullptr);
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virtual ~FutexQueue();
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u32 wake_n_requeue(u32, const Function<FutexQueue*()>&, u32, bool&, bool&);
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u32 wake_n(u32, const Optional<u32>&, bool&);
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u32 wake_all(bool&);
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template<class... Args>
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Thread::BlockResult wait_on(const Thread::BlockTimeout& timeout, Args&&... args)
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{
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return Thread::current()->block<Thread::FutexBlocker>(timeout, *this, forward<Args>(args)...);
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}
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virtual void vmobject_deleted(VMObject&) override;
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protected:
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virtual bool should_add_blocker(Thread::Blocker& b, void* data) override;
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private:
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// For private futexes we just use the user space address.
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// But for global futexes we use the offset into the VMObject
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const FlatPtr m_user_address_or_offset;
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WeakPtr<VMObject> m_vmobject;
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const bool m_is_global;
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};
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}
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