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#pragma once
#include "types.h"
#include "i386.h"
#include <AK/ByteBuffer.h>
#include <AK/Retainable.h>
#include <AK/RetainPtr.h>
#include <AK/Vector.h>
#include <AK/HashTable.h>
#include <AK/String.h>
class Process;
extern Process* current;
enum class PageFaultResponse {
ShouldCrash,
Continue,
};
struct PageDirectory {
dword entries[1024];
PhysicalAddress physical_addresses[1024];
};
struct Zone : public Retainable<Zone> {
friend ByteBuffer procfs$mm();
public:
~Zone();
size_t size() const { return m_pages.size() * PAGE_SIZE; }
const Vector<PhysicalAddress>& pages() const { return m_pages; }
private:
friend class MemoryManager;
explicit Zone(Vector<PhysicalAddress>&&);
Vector<PhysicalAddress> m_pages;
};
struct Region : public Retainable<Region> {
Region(LinearAddress, size_t, RetainPtr<Zone>&&, String&&);
~Region();
RetainPtr<Region> clone();
LinearAddress linearAddress;
size_t size { 0 };
RetainPtr<Zone> zone;
String name;
};
struct Subregion {
Subregion(Region&, dword offset, size_t, LinearAddress, String&& name);
~Subregion();
RetainPtr<Region> region;
dword offset;
size_t size { 0 };
LinearAddress linearAddress;
String name;
};
#define MM MemoryManager::the()
class MemoryManager {
AK_MAKE_ETERNAL
friend ByteBuffer procfs$mm();
public:
static MemoryManager& the() PURE;
PhysicalAddress pageDirectoryBase() const { return PhysicalAddress(reinterpret_cast<dword>(m_kernel_page_directory)); }
static void initialize();
PageFaultResponse handlePageFault(const PageFault&);
RetainPtr<Zone> createZone(size_t);
bool mapSubregion(Process&, Subregion&);
bool unmapSubregion(Process&, Subregion&);
bool mapRegion(Process&, Region&);
bool unmapRegion(Process&, Region&);
void registerZone(Zone&);
void unregisterZone(Zone&);
void populate_page_directory(Process&);
void release_page_directory(Process&);
byte* create_kernel_alias_for_region(Region&);
void remove_kernel_alias_for_region(Region&, byte*);
void enter_kernel_paging_scope();
void enter_process_paging_scope(Process&);
bool validate_user_read(const Process&, LinearAddress) const;
bool validate_user_write(const Process&, LinearAddress) const;
private:
MemoryManager();
~MemoryManager();
LinearAddress allocate_linear_address_range(size_t);
void map_region_at_address(PageDirectory*, Region&, LinearAddress, bool user_accessible);
void unmap_range(PageDirectory*, LinearAddress, size_t);
void initializePaging();
void flushEntireTLB();
void flushTLB(LinearAddress);
PhysicalAddress allocate_page_table();
void deallocate_page_table(PhysicalAddress);
void protectMap(LinearAddress, size_t length);
void create_identity_mapping(LinearAddress, size_t length);
void remove_identity_mapping(LinearAddress, size_t);
Vector<PhysicalAddress> allocatePhysicalPages(size_t count);
struct PageDirectoryEntry {
explicit PageDirectoryEntry(dword* pde) : m_pde(pde) { }
dword* pageTableBase() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
void setPageTableBase(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,
};
bool isPresent() const { return raw() & Present; }
void setPresent(bool b) { setBit(Present, b); }
bool isUserAllowed() const { return raw() & UserSupervisor; }
void setUserAllowed(bool b) { setBit(UserSupervisor, b); }
bool isWritable() const { return raw() & ReadWrite; }
void setWritable(bool b) { setBit(ReadWrite, b); }
void setBit(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* physicalPageBase() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
void setPhysicalPageBase(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,
};
bool isPresent() const { return raw() & Present; }
void setPresent(bool b) { setBit(Present, b); }
bool isUserAllowed() const { return raw() & UserSupervisor; }
void setUserAllowed(bool b) { setBit(UserSupervisor, b); }
bool isWritable() const { return raw() & ReadWrite; }
void setWritable(bool b) { setBit(ReadWrite, b); }
void setBit(byte bit, bool value)
{
if (value)
*m_pte |= bit;
else
*m_pte &= ~bit;
}
dword* m_pte;
};
PageTableEntry ensurePTE(PageDirectory*, LinearAddress);
PageDirectory* m_kernel_page_directory;
dword* m_pageTableZero;
dword* m_pageTableOne;
LinearAddress m_next_laddr;
HashTable<Zone*> m_zones;
Vector<PhysicalAddress> m_freePages;
};
struct KernelPagingScope {
KernelPagingScope() { MM.enter_kernel_paging_scope(); }
~KernelPagingScope() { MM.enter_process_paging_scope(*current); }
};
struct ProcessPagingScope {
ProcessPagingScope(Process& process) { MM.enter_process_paging_scope(process); }
~ProcessPagingScope() { MM.enter_process_paging_scope(*current); }
};
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