mirror of
https://github.com/RGBCube/serenity
synced 2025-05-18 17:45:08 +00:00
ca16d9d98e
The current strategy is simply to nuke all physical pages and force reload them from disk. This is obviously not optimal and should eventually be optimized. It should be fairly straightforward.
372 lines
10 KiB
C++
372 lines
10 KiB
C++
#pragma once
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#include "types.h"
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#include "i386.h"
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#include <AK/Bitmap.h>
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#include <AK/ByteBuffer.h>
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#include <AK/Retainable.h>
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#include <AK/RetainPtr.h>
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#include <AK/Vector.h>
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#include <AK/HashTable.h>
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#include <AK/AKString.h>
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#include <AK/Badge.h>
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#include <Kernel/VirtualFileSystem.h>
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#define PAGE_ROUND_UP(x) ((((dword)(x)) + PAGE_SIZE-1) & (~(PAGE_SIZE-1)))
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class Process;
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extern Process* current;
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class SynthFSInode;
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enum class PageFaultResponse {
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ShouldCrash,
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Continue,
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};
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class PhysicalPage {
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AK_MAKE_ETERNAL
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friend class MemoryManager;
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friend class PageDirectory;
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friend class VMObject;
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public:
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PhysicalAddress paddr() const { return m_paddr; }
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void retain()
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{
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ASSERT(m_retain_count);
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++m_retain_count;
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}
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void release()
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{
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ASSERT(m_retain_count);
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if (!--m_retain_count)
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return_to_freelist();
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}
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unsigned short retain_count() const { return m_retain_count; }
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private:
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PhysicalPage(PhysicalAddress paddr, bool supervisor);
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~PhysicalPage() = delete;
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void return_to_freelist();
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unsigned short m_retain_count { 1 };
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bool m_supervisor { false };
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PhysicalAddress m_paddr;
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};
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class PageDirectory : public Retainable<PageDirectory> {
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friend class MemoryManager;
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public:
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static RetainPtr<PageDirectory> create() { return adopt(*new PageDirectory); }
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static RetainPtr<PageDirectory> create_at_fixed_address(PhysicalAddress paddr) { return adopt(*new PageDirectory(paddr)); }
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~PageDirectory();
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dword cr3() const { return m_directory_page->paddr().get(); }
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dword* entries() { return reinterpret_cast<dword*>(cr3()); }
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void flush(LinearAddress);
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private:
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PageDirectory();
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explicit PageDirectory(PhysicalAddress);
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RetainPtr<PhysicalPage> m_directory_page;
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HashMap<unsigned, RetainPtr<PhysicalPage>> m_physical_pages;
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};
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class VMObject : public Retainable<VMObject> {
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friend class MemoryManager;
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public:
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static RetainPtr<VMObject> create_file_backed(RetainPtr<Inode>&&);
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static RetainPtr<VMObject> create_anonymous(size_t);
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static RetainPtr<VMObject> create_framebuffer_wrapper(PhysicalAddress, size_t);
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RetainPtr<VMObject> clone();
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~VMObject();
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bool is_anonymous() const { return m_anonymous; }
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Inode* inode() { return m_inode.ptr(); }
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const Inode* inode() const { return m_inode.ptr(); }
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size_t inode_offset() const { return m_inode_offset; }
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String name() const { return m_name; }
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void set_name(const String& name) { m_name = name; }
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size_t page_count() const { return m_size / PAGE_SIZE; }
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const Vector<RetainPtr<PhysicalPage>>& physical_pages() const { return m_physical_pages; }
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Vector<RetainPtr<PhysicalPage>>& physical_pages() { return m_physical_pages; }
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void inode_contents_changed(Badge<Inode>, off_t, size_t, const byte*);
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void inode_size_changed(Badge<Inode>, size_t old_size, size_t new_size);
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private:
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VMObject(RetainPtr<Inode>&&);
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explicit VMObject(VMObject&);
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explicit VMObject(size_t);
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VMObject(PhysicalAddress, size_t);
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template<typename Callback> void for_each_region(Callback);
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String m_name;
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bool m_anonymous { false };
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off_t m_inode_offset { 0 };
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size_t m_size { 0 };
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RetainPtr<Inode> m_inode;
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Vector<RetainPtr<PhysicalPage>> m_physical_pages;
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Lock m_paging_lock;
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};
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class Region : public Retainable<Region> {
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friend class MemoryManager;
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public:
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Region(LinearAddress, size_t, String&&, bool r, bool w, bool cow = false);
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Region(LinearAddress, size_t, RetainPtr<VMObject>&&, size_t offset_in_vmo, String&&, bool r, bool w, bool cow = false);
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Region(LinearAddress, size_t, RetainPtr<Inode>&&, String&&, bool r, bool w);
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~Region();
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LinearAddress laddr() const { return m_laddr; }
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size_t size() const { return m_size; }
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bool is_readable() const { return m_readable; }
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bool is_writable() const { return m_writable; }
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String name() const { return m_name; }
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void set_name(String&& name) { m_name = move(name); }
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const VMObject& vmo() const { return *m_vmo; }
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VMObject& vmo() { return *m_vmo; }
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void set_shared(bool shared) { m_shared = shared; }
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RetainPtr<Region> clone();
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bool contains(LinearAddress laddr) const
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{
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return laddr >= m_laddr && laddr < m_laddr.offset(size());
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}
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unsigned page_index_from_address(LinearAddress laddr) const
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{
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return (laddr - m_laddr).get() / PAGE_SIZE;
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}
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size_t first_page_index() const
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{
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return m_offset_in_vmo / PAGE_SIZE;
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}
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size_t last_page_index() const
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{
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return (first_page_index() + page_count()) - 1;
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}
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size_t page_count() const
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{
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return m_size / PAGE_SIZE;
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}
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bool page_in();
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int commit();
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size_t amount_resident() const;
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size_t amount_shared() const;
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PageDirectory* page_directory() { return m_page_directory.ptr(); }
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void set_page_directory(PageDirectory& page_directory)
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{
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ASSERT(!m_page_directory || m_page_directory.ptr() == &page_directory);
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m_page_directory = page_directory;
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}
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void release_page_directory()
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{
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ASSERT(m_page_directory);
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m_page_directory.clear();
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}
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const Bitmap& cow_map() const { return m_cow_map; }
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private:
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RetainPtr<PageDirectory> m_page_directory;
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LinearAddress m_laddr;
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size_t m_size { 0 };
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size_t m_offset_in_vmo { 0 };
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RetainPtr<VMObject> m_vmo;
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String m_name;
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bool m_readable { true };
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bool m_writable { true };
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bool m_shared { false };
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Bitmap m_cow_map;
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};
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#define MM MemoryManager::the()
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class MemoryManager {
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AK_MAKE_ETERNAL
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friend class PageDirectory;
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friend class PhysicalPage;
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friend class Region;
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friend class VMObject;
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friend ByteBuffer procfs$mm(InodeIdentifier);
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public:
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static MemoryManager& the() PURE;
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static void initialize();
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PageFaultResponse handle_page_fault(const PageFault&);
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bool map_region(Process&, Region&);
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bool unmap_region(Region&);
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void populate_page_directory(PageDirectory&);
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void enter_process_paging_scope(Process&);
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bool validate_user_read(const Process&, LinearAddress) const;
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bool validate_user_write(const Process&, LinearAddress) const;
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enum class ShouldZeroFill { No, Yes };
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RetainPtr<PhysicalPage> allocate_physical_page(ShouldZeroFill);
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RetainPtr<PhysicalPage> allocate_supervisor_physical_page();
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void remap_region(PageDirectory&, Region&);
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size_t ram_size() const { return m_ram_size; }
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private:
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MemoryManager();
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~MemoryManager();
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void register_vmo(VMObject&);
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void unregister_vmo(VMObject&);
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void register_region(Region&);
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void unregister_region(Region&);
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void map_region_at_address(PageDirectory&, Region&, LinearAddress, bool user_accessible);
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void remap_region_page(Region&, unsigned page_index_in_region, bool user_allowed);
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void initialize_paging();
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void flush_entire_tlb();
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void flush_tlb(LinearAddress);
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RetainPtr<PhysicalPage> allocate_page_table(PageDirectory&, unsigned index);
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void map_protected(LinearAddress, size_t length);
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void create_identity_mapping(PageDirectory&, LinearAddress, size_t length);
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void remove_identity_mapping(PageDirectory&, LinearAddress, size_t);
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static Region* region_from_laddr(Process&, LinearAddress);
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static const Region* region_from_laddr(const Process&, LinearAddress);
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bool copy_on_write(Region&, unsigned page_index_in_region);
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bool page_in_from_inode(Region&, unsigned page_index_in_region);
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bool zero_page(Region& region, unsigned page_index_in_region);
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byte* quickmap_page(PhysicalPage&);
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void unquickmap_page();
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PageDirectory& kernel_page_directory() { return *m_kernel_page_directory; }
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struct PageDirectoryEntry {
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explicit PageDirectoryEntry(dword* pde) : m_pde(pde) { }
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dword* page_table_base() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
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void set_page_table_base(dword value)
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{
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*m_pde &= 0xfff;
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*m_pde |= value & 0xfffff000;
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}
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dword raw() const { return *m_pde; }
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dword* ptr() { return m_pde; }
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enum Flags {
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Present = 1 << 0,
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ReadWrite = 1 << 1,
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UserSupervisor = 1 << 2,
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};
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bool is_present() const { return raw() & Present; }
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void set_present(bool b) { set_bit(Present, b); }
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bool is_user_allowed() const { return raw() & UserSupervisor; }
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void set_user_allowed(bool b) { set_bit(UserSupervisor, b); }
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bool is_writable() const { return raw() & ReadWrite; }
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void set_writable(bool b) { set_bit(ReadWrite, b); }
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void set_bit(byte bit, bool value)
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{
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if (value)
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*m_pde |= bit;
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else
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*m_pde &= ~bit;
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}
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dword* m_pde;
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};
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struct PageTableEntry {
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explicit PageTableEntry(dword* pte) : m_pte(pte) { }
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dword* physical_page_base() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
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void set_physical_page_base(dword value)
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{
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*m_pte &= 0xfffu;
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*m_pte |= value & 0xfffff000u;
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}
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dword raw() const { return *m_pte; }
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dword* ptr() { return m_pte; }
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enum Flags {
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Present = 1 << 0,
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ReadWrite = 1 << 1,
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UserSupervisor = 1 << 2,
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};
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bool is_present() const { return raw() & Present; }
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void set_present(bool b) { set_bit(Present, b); }
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bool is_user_allowed() const { return raw() & UserSupervisor; }
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void set_user_allowed(bool b) { set_bit(UserSupervisor, b); }
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bool is_writable() const { return raw() & ReadWrite; }
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void set_writable(bool b) { set_bit(ReadWrite, b); }
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void set_bit(byte bit, bool value)
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{
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if (value)
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*m_pte |= bit;
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else
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*m_pte &= ~bit;
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}
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dword* m_pte;
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};
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PageTableEntry ensure_pte(PageDirectory&, LinearAddress);
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RetainPtr<PageDirectory> m_kernel_page_directory;
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dword* m_page_table_zero;
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LinearAddress m_quickmap_addr;
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Vector<RetainPtr<PhysicalPage>> m_free_physical_pages;
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Vector<RetainPtr<PhysicalPage>> m_free_supervisor_physical_pages;
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HashTable<VMObject*> m_vmos;
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HashTable<Region*> m_regions;
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size_t m_ram_size { 0 };
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bool m_quickmap_in_use { false };
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};
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struct ProcessPagingScope {
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ProcessPagingScope(Process& process) { MM.enter_process_paging_scope(process); }
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~ProcessPagingScope() { MM.enter_process_paging_scope(*current); }
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};
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