PageTables.h

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#ifndef PAGE_TABLES_H_
#define PAGE_TABLES_H_
 
#define SYS_CODE64_SEL  0x38
 
#pragma pack(1)
 
typedef union {
  struct {
    UINT32    LimitLow    : 16;
    UINT32    BaseLow     : 16;
    UINT32    BaseMid     : 8;
    UINT32    Type        : 4;
    UINT32    System      : 1;
    UINT32    Dpl         : 2;
    UINT32    Present     : 1;
    UINT32    LimitHigh   : 4;
    UINT32    Software    : 1;
    UINT32    Reserved    : 1;
    UINT32    DefaultSize : 1;
    UINT32    Granularity : 1;
    UINT32    BaseHigh    : 8;
  } Bits;
  UINT64    Uint64;
} IA32_GDT;
 
typedef struct {
  IA32_IDT_GATE_DESCRIPTOR    Ia32IdtEntry;
  UINT32                      Offset32To63;
  UINT32                      Reserved;
} X64_IDT_GATE_DESCRIPTOR;
 
//
// Page-Map Level-4 Offset (PML4) and
// Page-Directory-Pointer Offset (PDPE) entries 4K & 2MB
//
 
typedef union {
  struct {
    UINT64    Present              : 1;  // 0 = Not present in memory, 1 = Present in memory
    UINT64    ReadWrite            : 1;  // 0 = Read-Only, 1= Read/Write
    UINT64    UserSupervisor       : 1;  // 0 = Supervisor, 1=User
    UINT64    WriteThrough         : 1;  // 0 = Write-Back caching, 1=Write-Through caching
    UINT64    CacheDisabled        : 1;  // 0 = Cached, 1=Non-Cached
    UINT64    Accessed             : 1;  // 0 = Not accessed, 1 = Accessed (set by CPU)
    UINT64    Reserved             : 1;  // Reserved
    UINT64    MustBeZero           : 2;  // Must Be Zero
    UINT64    Available            : 3;  // Available for use by system software
    UINT64    PageTableBaseAddress : 40; // Page Table Base Address
    UINT64    AvabilableHigh       : 11; // Available for use by system software
    UINT64    Nx                   : 1;  // No Execute bit
  } Bits;
  UINT64    Uint64;
} PAGE_MAP_AND_DIRECTORY_POINTER;
 
//
// Page Table Entry 4KB
//
typedef union {
  struct {
    UINT64    Present              : 1;  // 0 = Not present in memory, 1 = Present in memory
    UINT64    ReadWrite            : 1;  // 0 = Read-Only, 1= Read/Write
    UINT64    UserSupervisor       : 1;  // 0 = Supervisor, 1=User
    UINT64    WriteThrough         : 1;  // 0 = Write-Back caching, 1=Write-Through caching
    UINT64    CacheDisabled        : 1;  // 0 = Cached, 1=Non-Cached
    UINT64    Accessed             : 1;  // 0 = Not accessed, 1 = Accessed (set by CPU)
    UINT64    Dirty                : 1;  // 0 = Not Dirty, 1 = written by processor on access to page
    UINT64    PAT                  : 1;  //
    UINT64    Global               : 1;  // 0 = Not global page, 1 = global page TLB not cleared on CR3 write
    UINT64    Available            : 3;  // Available for use by system software
    UINT64    PageTableBaseAddress : 40; // Page Table Base Address
    UINT64    AvabilableHigh       : 11; // Available for use by system software
    UINT64    Nx                   : 1;  // 0 = Execute Code, 1 = No Code Execution
  } Bits;
  UINT64    Uint64;
} PAGE_TABLE_4K_ENTRY;
 
//
// Page Table Entry 2MB
//
typedef union {
  struct {
    UINT64    Present              : 1;  // 0 = Not present in memory, 1 = Present in memory
    UINT64    ReadWrite            : 1;  // 0 = Read-Only, 1= Read/Write
    UINT64    UserSupervisor       : 1;  // 0 = Supervisor, 1=User
    UINT64    WriteThrough         : 1;  // 0 = Write-Back caching, 1=Write-Through caching
    UINT64    CacheDisabled        : 1;  // 0 = Cached, 1=Non-Cached
    UINT64    Accessed             : 1;  // 0 = Not accessed, 1 = Accessed (set by CPU)
    UINT64    Dirty                : 1;  // 0 = Not Dirty, 1 = written by processor on access to page
    UINT64    MustBe1              : 1;  // Must be 1
    UINT64    Global               : 1;  // 0 = Not global page, 1 = global page TLB not cleared on CR3 write
    UINT64    Available            : 3;  // Available for use by system software
    UINT64    PAT                  : 1;  //
    UINT64    MustBeZero           : 8;  // Must be zero;
    UINT64    PageTableBaseAddress : 31; // Page Table Base Address
    UINT64    AvabilableHigh       : 11; // Available for use by system software
    UINT64    Nx                   : 1;  // 0 = Execute Code, 1 = No Code Execution
  } Bits;
  UINT64    Uint64;
} PAGE_TABLE_ENTRY;
 
//
// Page Table Entry 1GB
//
typedef union {
  struct {
    UINT64    Present              : 1;  // 0 = Not present in memory, 1 = Present in memory
    UINT64    ReadWrite            : 1;  // 0 = Read-Only, 1= Read/Write
    UINT64    UserSupervisor       : 1;  // 0 = Supervisor, 1=User
    UINT64    WriteThrough         : 1;  // 0 = Write-Back caching, 1=Write-Through caching
    UINT64    CacheDisabled        : 1;  // 0 = Cached, 1=Non-Cached
    UINT64    Accessed             : 1;  // 0 = Not accessed, 1 = Accessed (set by CPU)
    UINT64    Dirty                : 1;  // 0 = Not Dirty, 1 = written by processor on access to page
    UINT64    MustBe1              : 1;  // Must be 1
    UINT64    Global               : 1;  // 0 = Not global page, 1 = global page TLB not cleared on CR3 write
    UINT64    Available            : 3;  // Available for use by system software
    UINT64    PAT                  : 1;  //
    UINT64    MustBeZero           : 17; // Must be zero;
    UINT64    PageTableBaseAddress : 22; // Page Table Base Address
    UINT64    AvabilableHigh       : 11; // Available for use by system software
    UINT64    Nx                   : 1;  // 0 = Execute Code, 1 = No Code Execution
  } Bits;
  UINT64    Uint64;
} PAGE_TABLE_1G_ENTRY;
 
#pragma pack()
 
#define CR0_WP  BIT16
 
#define IA32_PG_P   BIT0
#define IA32_PG_RW  BIT1
#define IA32_PG_PS  BIT7
 
#define PAGING_PAE_INDEX_MASK  0x1FF
 
#define PAGING_4K_ADDRESS_MASK_64  0x000FFFFFFFFFF000ull
#define PAGING_2M_ADDRESS_MASK_64  0x000FFFFFFFE00000ull
#define PAGING_1G_ADDRESS_MASK_64  0x000FFFFFC0000000ull
 
#define PAGING_L1_ADDRESS_SHIFT  12
#define PAGING_L2_ADDRESS_SHIFT  21
#define PAGING_L3_ADDRESS_SHIFT  30
#define PAGING_L4_ADDRESS_SHIFT  39
 
#define PAGING_PML4E_NUMBER  4
 
#define PAGE_TABLE_POOL_ALIGNMENT   BASE_2MB
#define PAGE_TABLE_POOL_UNIT_SIZE   SIZE_2MB
#define PAGE_TABLE_POOL_UNIT_PAGES  EFI_SIZE_TO_PAGES (PAGE_TABLE_POOL_UNIT_SIZE)
#define PAGE_TABLE_POOL_ALIGN_MASK  \
  (~(EFI_PHYSICAL_ADDRESS)(PAGE_TABLE_POOL_ALIGNMENT - 1))
 
typedef struct {
  VOID     *NextPool;
  UINTN    Offset;
  UINTN    FreePages;
} PAGE_TABLE_POOL;
 
UINTN
CreateIdentityMappingPageTables (
  IN EFI_PHYSICAL_ADDRESS  StackBase,
  IN UINTN                 StackSize
  );
 
VOID
ClearFirst4KPage (
  IN  VOID  *HobStart
  );
 
BOOLEAN
IsNullDetectionEnabled (
  VOID
  );
 
#endif