/* * Copyright (c) 2018-2020, Andreas Kling * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #pragma once #include #include #include #include #include namespace Kernel { class PhysicalPage { friend class MemoryManager; friend class PageDirectory; friend class VMObject; MAKE_SLAB_ALLOCATED(PhysicalPage); AK_MAKE_NONMOVABLE(PhysicalPage); public: PhysicalAddress paddr() const { return m_paddr; } void ref() { m_ref_count.fetch_add(1, AK::memory_order_acq_rel); } void unref() { if (m_ref_count.fetch_sub(1, AK::memory_order_acq_rel) == 1) { if (m_may_return_to_freelist) return_to_freelist(); delete this; } } static NonnullRefPtr create(PhysicalAddress, bool supervisor, bool may_return_to_freelist = true); u32 ref_count() const { return m_ref_count.load(AK::memory_order_consume); } bool is_shared_zero_page() const; bool is_lazy_committed_page() const; private: PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist = true); ~PhysicalPage() { } void return_to_freelist() const; Atomic m_ref_count { 1 }; bool m_may_return_to_freelist { true }; bool m_supervisor { false }; PhysicalAddress m_paddr; }; }