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https://github.com/RGBCube/serenity
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f35108fc31
This patch gets rid of the "valid" bit in PageDirectory since it was only used to communicate an allocation failure during construction. We now do all the work in the static factory functions instead of in the constructor, which allows us to simply return nullptr instead of an "invalid" PageDirectory.
70 lines
1.8 KiB
C++
70 lines
1.8 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/HashMap.h>
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#include <AK/RefCounted.h>
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#include <AK/RefPtr.h>
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#include <Kernel/Forward.h>
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#include <Kernel/VM/PhysicalPage.h>
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#include <Kernel/VM/RangeAllocator.h>
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namespace Kernel {
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class PageDirectory : public RefCounted<PageDirectory> {
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friend class MemoryManager;
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public:
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static RefPtr<PageDirectory> try_create_for_userspace(RangeAllocator const* parent_range_allocator = nullptr);
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static NonnullRefPtr<PageDirectory> must_create_kernel_page_directory();
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static RefPtr<PageDirectory> find_by_cr3(FlatPtr);
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~PageDirectory();
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void allocate_kernel_directory();
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FlatPtr cr3() const
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{
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#if ARCH(X86_64)
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return m_pml4t->paddr().get();
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#else
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return m_directory_table->paddr().get();
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#endif
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}
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RangeAllocator& range_allocator() { return m_range_allocator; }
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const RangeAllocator& range_allocator() const { return m_range_allocator; }
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RangeAllocator& identity_range_allocator() { return m_identity_range_allocator; }
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Space* space() { return m_space; }
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const Space* space() const { return m_space; }
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void set_space(Badge<Space>, Space& space) { m_space = &space; }
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RecursiveSpinLock& get_lock() { return m_lock; }
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private:
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PageDirectory();
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Space* m_space { nullptr };
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RangeAllocator m_range_allocator;
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RangeAllocator m_identity_range_allocator;
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#if ARCH(X86_64)
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RefPtr<PhysicalPage> m_pml4t;
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#endif
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RefPtr<PhysicalPage> m_directory_table;
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#if ARCH(X86_64)
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RefPtr<PhysicalPage> m_directory_pages[512];
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#else
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RefPtr<PhysicalPage> m_directory_pages[4];
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#endif
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HashMap<FlatPtr, RefPtr<PhysicalPage>> m_page_tables;
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RecursiveSpinLock m_lock;
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};
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}
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