Kernel: Move VM-related files into Kernel/VM/.

Also break MemoryManager.{cpp,h} into one file per class.

Kernel/VM/MemoryManager.h

@@ -0,0 +1,227 @@
+#pragma once
+
+#include "types.h"
+#include "i386.h"
+#include <AK/Bitmap.h>
+#include <AK/ByteBuffer.h>
+#include <AK/Retainable.h>
+#include <AK/RetainPtr.h>
+#include <AK/Vector.h>
+#include <AK/HashTable.h>
+#include <AK/AKString.h>
+#include <AK/Badge.h>
+#include <AK/Weakable.h>
+#include <Kernel/VM/PhysicalPage.h>
+#include <Kernel/VM/Region.h>
+#include <Kernel/VM/VMObject.h>
+#include <Kernel/FileSystem/InodeIdentifier.h>
+
+#define PAGE_ROUND_UP(x) ((((dword)(x)) + PAGE_SIZE-1) & (~(PAGE_SIZE-1)))
+
+class SynthFSInode;
+
+enum class PageFaultResponse {
+    ShouldCrash,
+    Continue,
+};
+
+#define MM MemoryManager::the()
+
+class MemoryManager {
+    AK_MAKE_ETERNAL
+    friend class PageDirectory;
+    friend class PhysicalPage;
+    friend class Region;
+    friend class VMObject;
+    friend ByteBuffer procfs$mm(InodeIdentifier);
+    friend ByteBuffer procfs$memstat(InodeIdentifier);
+public:
+    [[gnu::pure]] static MemoryManager& the();
+
+    static void initialize();
+
+    PageFaultResponse handle_page_fault(const PageFault&);
+
+    bool map_region(Process&, Region&);
+    bool unmap_region(Region&);
+
+    void populate_page_directory(PageDirectory&);
+
+    void enter_process_paging_scope(Process&);
+    void enter_kernel_paging_scope();
+
+    bool validate_user_read(const Process&, LinearAddress) const;
+    bool validate_user_write(const Process&, LinearAddress) const;
+
+    enum class ShouldZeroFill { No, Yes };
+
+    RetainPtr<PhysicalPage> allocate_physical_page(ShouldZeroFill);
+    RetainPtr<PhysicalPage> allocate_supervisor_physical_page();
+
+    void remap_region(PageDirectory&, Region&);
+
+    size_t ram_size() const { return m_ram_size; }
+
+    int user_physical_pages_in_existence() const { return s_user_physical_pages_in_existence; }
+    int super_physical_pages_in_existence() const { return s_super_physical_pages_in_existence; }
+
+    void map_for_kernel(LinearAddress, PhysicalAddress);
+
+private:
+    MemoryManager();
+    ~MemoryManager();
+
+    void register_vmo(VMObject&);
+    void unregister_vmo(VMObject&);
+    void register_region(Region&);
+    void unregister_region(Region&);
+
+    void map_region_at_address(PageDirectory&, Region&, LinearAddress, bool user_accessible);
+    void remap_region_page(Region&, unsigned page_index_in_region, bool user_allowed);
+
+    void initialize_paging();
+    void flush_entire_tlb();
+    void flush_tlb(LinearAddress);
+
+    RetainPtr<PhysicalPage> allocate_page_table(PageDirectory&, unsigned index);
+
+    void map_protected(LinearAddress, size_t length);
+
+    void create_identity_mapping(PageDirectory&, LinearAddress, size_t length);
+    void remove_identity_mapping(PageDirectory&, LinearAddress, size_t);
+
+    static Region* region_from_laddr(Process&, LinearAddress);
+    static const Region* region_from_laddr(const Process&, LinearAddress);
+
+    bool copy_on_write(Region&, unsigned page_index_in_region);
+    bool page_in_from_inode(Region&, unsigned page_index_in_region);
+    bool zero_page(Region& region, unsigned page_index_in_region);
+
+    byte* quickmap_page(PhysicalPage&);
+    void unquickmap_page();
+
+    PageDirectory& kernel_page_directory() { return *m_kernel_page_directory; }
+
+    struct PageDirectoryEntry {
+        explicit PageDirectoryEntry(dword* pde) : m_pde(pde) { }
+
+        dword* page_table_base() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
+        void set_page_table_base(dword value)
+        {
+            *m_pde &= 0xfff;
+            *m_pde |= value & 0xfffff000;
+        }
+
+        dword raw() const { return *m_pde; }
+        dword* ptr() { return m_pde; }
+
+        enum Flags {
+            Present = 1 << 0,
+            ReadWrite = 1 << 1,
+            UserSupervisor = 1 << 2,
+            WriteThrough = 1 << 3,
+            CacheDisabled = 1 << 4,
+        };
+
+        bool is_present() const { return raw() & Present; }
+        void set_present(bool b) { set_bit(Present, b); }
+
+        bool is_user_allowed() const { return raw() & UserSupervisor; }
+        void set_user_allowed(bool b) { set_bit(UserSupervisor, b); }
+
+        bool is_writable() const { return raw() & ReadWrite; }
+        void set_writable(bool b) { set_bit(ReadWrite, b); }
+
+        bool is_write_through() const { return raw() & WriteThrough; }
+        void set_write_through(bool b) { set_bit(WriteThrough, b); }
+
+        bool is_cache_disabled() const { return raw() & CacheDisabled; }
+        void set_cache_disabled(bool b) { set_bit(CacheDisabled, b); }
+
+        void set_bit(byte bit, bool value)
+        {
+            if (value)
+                *m_pde |= bit;
+            else
+                *m_pde &= ~bit;
+        }
+
+        dword* m_pde;
+    };
+
+    struct PageTableEntry {
+        explicit PageTableEntry(dword* pte) : m_pte(pte) { }
+
+        dword* physical_page_base() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
+        void set_physical_page_base(dword value)
+        {
+            *m_pte &= 0xfffu;
+            *m_pte |= value & 0xfffff000u;
+        }
+
+        dword raw() const { return *m_pte; }
+        dword* ptr() { return m_pte; }
+
+        enum Flags {
+            Present = 1 << 0,
+            ReadWrite = 1 << 1,
+            UserSupervisor = 1 << 2,
+            WriteThrough = 1 << 3,
+            CacheDisabled = 1 << 4,
+        };
+
+        bool is_present() const { return raw() & Present; }
+        void set_present(bool b) { set_bit(Present, b); }
+
+        bool is_user_allowed() const { return raw() & UserSupervisor; }
+        void set_user_allowed(bool b) { set_bit(UserSupervisor, b); }
+
+        bool is_writable() const { return raw() & ReadWrite; }
+        void set_writable(bool b) { set_bit(ReadWrite, b); }
+
+        bool is_write_through() const { return raw() & WriteThrough; }
+        void set_write_through(bool b) { set_bit(WriteThrough, b); }
+
+        bool is_cache_disabled() const { return raw() & CacheDisabled; }
+        void set_cache_disabled(bool b) { set_bit(CacheDisabled, b); }
+
+        void set_bit(byte bit, bool value)
+        {
+            if (value)
+                *m_pte |= bit;
+            else
+                *m_pte &= ~bit;
+        }
+
+        dword* m_pte;
+    };
+
+    static unsigned s_user_physical_pages_in_existence;
+    static unsigned s_super_physical_pages_in_existence;
+
+    PageTableEntry ensure_pte(PageDirectory&, LinearAddress);
+
+    RetainPtr<PageDirectory> m_kernel_page_directory;
+    dword* m_page_table_zero;
+
+    LinearAddress m_quickmap_addr;
+
+    Vector<Retained<PhysicalPage>> m_free_physical_pages;
+    Vector<Retained<PhysicalPage>> m_free_supervisor_physical_pages;
+
+    HashTable<VMObject*> m_vmos;
+    HashTable<Region*> m_regions;
+
+    size_t m_ram_size { 0 };
+    bool m_quickmap_in_use { false };
+};
+
+struct ProcessPagingScope {
+    ProcessPagingScope(Process&);
+    ~ProcessPagingScope();
+};
+
+struct KernelPagingScope {
+    KernelPagingScope();
+    ~KernelPagingScope();
+};