Renormalized end-of-lines from master@27b044605cd5f6b33a3d231576003850b3fe305btrunk

1 files changed, 1755 insertions, 1755 deletions

diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
index 0c0ca61872..0f5cfaeff1 100644
--- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
@@ -1,1755 +1,1755 @@
-/** @file

-  UEFI Heap Guard functions.

-

-Copyright (c) 2017-2018, Intel Corporation. All rights reserved.<BR>

-SPDX-License-Identifier: BSD-2-Clause-Patent

-

-**/

-

-#include "DxeMain.h"

-#include "Imem.h"

-#include "HeapGuard.h"

-

-//

-// Global to avoid infinite reentrance of memory allocation when updating

-// page table attributes, which may need allocate pages for new PDE/PTE.

-//

-GLOBAL_REMOVE_IF_UNREFERENCED BOOLEAN  mOnGuarding = FALSE;

-

-//

-// Pointer to table tracking the Guarded memory with bitmap, in which  '1'

-// is used to indicate memory guarded. '0' might be free memory or Guard

-// page itself, depending on status of memory adjacent to it.

-//

-GLOBAL_REMOVE_IF_UNREFERENCED UINT64  mGuardedMemoryMap = 0;

-

-//

-// Current depth level of map table pointed by mGuardedMemoryMap.

-// mMapLevel must be initialized at least by 1. It will be automatically

-// updated according to the address of memory just tracked.

-//

-GLOBAL_REMOVE_IF_UNREFERENCED UINTN  mMapLevel = 1;

-

-//

-// Shift and mask for each level of map table

-//

-GLOBAL_REMOVE_IF_UNREFERENCED UINTN  mLevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH]

-  = GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS;

-GLOBAL_REMOVE_IF_UNREFERENCED UINTN  mLevelMask[GUARDED_HEAP_MAP_TABLE_DEPTH]

-  = GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS;

-

-//

-// Used for promoting freed but not used pages.

-//

-GLOBAL_REMOVE_IF_UNREFERENCED EFI_PHYSICAL_ADDRESS  mLastPromotedPage = BASE_4GB;

-

-/**

-  Set corresponding bits in bitmap table to 1 according to the address.

-

-  @param[in]  Address     Start address to set for.

-  @param[in]  BitNumber   Number of bits to set.

-  @param[in]  BitMap      Pointer to bitmap which covers the Address.

-

-  @return VOID.

-**/

-STATIC

-VOID

-SetBits (

-  IN EFI_PHYSICAL_ADDRESS  Address,

-  IN UINTN                 BitNumber,

-  IN UINT64                *BitMap

-  )

-{

-  UINTN  Lsbs;

-  UINTN  Qwords;

-  UINTN  Msbs;

-  UINTN  StartBit;

-  UINTN  EndBit;

-

-  StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);

-  EndBit   = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;

-

-  if ((StartBit + BitNumber) >= GUARDED_HEAP_MAP_ENTRY_BITS) {

-    Msbs = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %

-           GUARDED_HEAP_MAP_ENTRY_BITS;

-    Lsbs   = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;

-    Qwords = (BitNumber - Msbs) / GUARDED_HEAP_MAP_ENTRY_BITS;

-  } else {

-    Msbs   = BitNumber;

-    Lsbs   = 0;

-    Qwords = 0;

-  }

-

-  if (Msbs > 0) {

-    *BitMap |= LShiftU64 (LShiftU64 (1, Msbs) - 1, StartBit);

-    BitMap  += 1;

-  }

-

-  if (Qwords > 0) {

-    SetMem64 (

-      (VOID *)BitMap,

-      Qwords * GUARDED_HEAP_MAP_ENTRY_BYTES,

-      (UINT64)-1

-      );

-    BitMap += Qwords;

-  }

-

-  if (Lsbs > 0) {

-    *BitMap |= (LShiftU64 (1, Lsbs) - 1);

-  }

-}

-

-/**

-  Set corresponding bits in bitmap table to 0 according to the address.

-

-  @param[in]  Address     Start address to set for.

-  @param[in]  BitNumber   Number of bits to set.

-  @param[in]  BitMap      Pointer to bitmap which covers the Address.

-

-  @return VOID.

-**/

-STATIC

-VOID

-ClearBits (

-  IN EFI_PHYSICAL_ADDRESS  Address,

-  IN UINTN                 BitNumber,

-  IN UINT64                *BitMap

-  )

-{

-  UINTN  Lsbs;

-  UINTN  Qwords;

-  UINTN  Msbs;

-  UINTN  StartBit;

-  UINTN  EndBit;

-

-  StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);

-  EndBit   = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;

-

-  if ((StartBit + BitNumber) >= GUARDED_HEAP_MAP_ENTRY_BITS) {

-    Msbs = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %

-           GUARDED_HEAP_MAP_ENTRY_BITS;

-    Lsbs   = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;

-    Qwords = (BitNumber - Msbs) / GUARDED_HEAP_MAP_ENTRY_BITS;

-  } else {

-    Msbs   = BitNumber;

-    Lsbs   = 0;

-    Qwords = 0;

-  }

-

-  if (Msbs > 0) {

-    *BitMap &= ~LShiftU64 (LShiftU64 (1, Msbs) - 1, StartBit);

-    BitMap  += 1;

-  }

-

-  if (Qwords > 0) {

-    SetMem64 ((VOID *)BitMap, Qwords * GUARDED_HEAP_MAP_ENTRY_BYTES, 0);

-    BitMap += Qwords;

-  }

-

-  if (Lsbs > 0) {

-    *BitMap &= ~(LShiftU64 (1, Lsbs) - 1);

-  }

-}

-

-/**

-  Get corresponding bits in bitmap table according to the address.

-

-  The value of bit 0 corresponds to the status of memory at given Address.

-  No more than 64 bits can be retrieved in one call.

-

-  @param[in]  Address     Start address to retrieve bits for.

-  @param[in]  BitNumber   Number of bits to get.

-  @param[in]  BitMap      Pointer to bitmap which covers the Address.

-

-  @return An integer containing the bits information.

-**/

-STATIC

-UINT64

-GetBits (

-  IN EFI_PHYSICAL_ADDRESS  Address,

-  IN UINTN                 BitNumber,

-  IN UINT64                *BitMap

-  )

-{

-  UINTN   StartBit;

-  UINTN   EndBit;

-  UINTN   Lsbs;

-  UINTN   Msbs;

-  UINT64  Result;

-

-  ASSERT (BitNumber <= GUARDED_HEAP_MAP_ENTRY_BITS);

-

-  StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);

-  EndBit   = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;

-

-  if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) {

-    Msbs = GUARDED_HEAP_MAP_ENTRY_BITS - StartBit;

-    Lsbs = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;

-  } else {

-    Msbs = BitNumber;

-    Lsbs = 0;

-  }

-

-  if ((StartBit == 0) && (BitNumber == GUARDED_HEAP_MAP_ENTRY_BITS)) {

-    Result = *BitMap;

-  } else {

-    Result = RShiftU64 ((*BitMap), StartBit) & (LShiftU64 (1, Msbs) - 1);

-    if (Lsbs > 0) {

-      BitMap += 1;

-      Result |= LShiftU64 ((*BitMap) & (LShiftU64 (1, Lsbs) - 1), Msbs);

-    }

-  }

-

-  return Result;

-}

-

-/**

-  Locate the pointer of bitmap from the guarded memory bitmap tables, which

-  covers the given Address.

-

-  @param[in]  Address       Start address to search the bitmap for.

-  @param[in]  AllocMapUnit  Flag to indicate memory allocation for the table.

-  @param[out] BitMap        Pointer to bitmap which covers the Address.

-

-  @return The bit number from given Address to the end of current map table.

-**/

-UINTN

-FindGuardedMemoryMap (

-  IN  EFI_PHYSICAL_ADDRESS  Address,

-  IN  BOOLEAN               AllocMapUnit,

-  OUT UINT64                **BitMap

-  )

-{

-  UINTN       Level;

-  UINT64      *GuardMap;

-  UINT64      MapMemory;

-  UINTN       Index;

-  UINTN       Size;

-  UINTN       BitsToUnitEnd;

-  EFI_STATUS  Status;

-

-  MapMemory = 0;

-

-  //

-  // Adjust current map table depth according to the address to access

-  //

-  while (AllocMapUnit &&

-         mMapLevel < GUARDED_HEAP_MAP_TABLE_DEPTH &&

-         RShiftU64 (

-           Address,

-           mLevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1]

-           ) != 0)

-  {

-    if (mGuardedMemoryMap != 0) {

-      Size = (mLevelMask[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1] + 1)

-             * GUARDED_HEAP_MAP_ENTRY_BYTES;

-      Status = CoreInternalAllocatePages (

-                 AllocateAnyPages,

-                 EfiBootServicesData,

-                 EFI_SIZE_TO_PAGES (Size),

-                 &MapMemory,

-                 FALSE

-                 );

-      ASSERT_EFI_ERROR (Status);

-      ASSERT (MapMemory != 0);

-

-      SetMem ((VOID *)(UINTN)MapMemory, Size, 0);

-

-      *(UINT64 *)(UINTN)MapMemory = mGuardedMemoryMap;

-      mGuardedMemoryMap           = MapMemory;

-    }

-

-    mMapLevel++;

-  }

-

-  GuardMap = &mGuardedMemoryMap;

-  for (Level = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;

-       Level < GUARDED_HEAP_MAP_TABLE_DEPTH;

-       ++Level)

-  {

-    if (*GuardMap == 0) {

-      if (!AllocMapUnit) {

-        GuardMap = NULL;

-        break;

-      }

-

-      Size   = (mLevelMask[Level] + 1) * GUARDED_HEAP_MAP_ENTRY_BYTES;

-      Status = CoreInternalAllocatePages (

-                 AllocateAnyPages,

-                 EfiBootServicesData,

-                 EFI_SIZE_TO_PAGES (Size),

-                 &MapMemory,

-                 FALSE

-                 );

-      ASSERT_EFI_ERROR (Status);

-      ASSERT (MapMemory != 0);

-

-      SetMem ((VOID *)(UINTN)MapMemory, Size, 0);

-      *GuardMap = MapMemory;

-    }

-

-    Index    = (UINTN)RShiftU64 (Address, mLevelShift[Level]);

-    Index   &= mLevelMask[Level];

-    GuardMap = (UINT64 *)(UINTN)((*GuardMap) + Index * sizeof (UINT64));

-  }

-

-  BitsToUnitEnd = GUARDED_HEAP_MAP_BITS - GUARDED_HEAP_MAP_BIT_INDEX (Address);

-  *BitMap       = GuardMap;

-

-  return BitsToUnitEnd;

-}

-

-/**

-  Set corresponding bits in bitmap table to 1 according to given memory range.

-

-  @param[in]  Address       Memory address to guard from.

-  @param[in]  NumberOfPages Number of pages to guard.

-

-  @return VOID.

-**/

-VOID

-EFIAPI

-SetGuardedMemoryBits (

-  IN EFI_PHYSICAL_ADDRESS  Address,

-  IN UINTN                 NumberOfPages

-  )

-{

-  UINT64  *BitMap;

-  UINTN   Bits;

-  UINTN   BitsToUnitEnd;

-

-  while (NumberOfPages > 0) {

-    BitsToUnitEnd = FindGuardedMemoryMap (Address, TRUE, &BitMap);

-    ASSERT (BitMap != NULL);

-

-    if (NumberOfPages > BitsToUnitEnd) {

-      // Cross map unit

-      Bits = BitsToUnitEnd;

-    } else {

-      Bits = NumberOfPages;

-    }

-

-    SetBits (Address, Bits, BitMap);

-

-    NumberOfPages -= Bits;

-    Address       += EFI_PAGES_TO_SIZE (Bits);

-  }

-}

-

-/**

-  Clear corresponding bits in bitmap table according to given memory range.

-

-  @param[in]  Address       Memory address to unset from.

-  @param[in]  NumberOfPages Number of pages to unset guard.

-

-  @return VOID.

-**/

-VOID

-EFIAPI

-ClearGuardedMemoryBits (

-  IN EFI_PHYSICAL_ADDRESS  Address,

-  IN UINTN                 NumberOfPages

-  )

-{

-  UINT64  *BitMap;

-  UINTN   Bits;

-  UINTN   BitsToUnitEnd;

-

-  while (NumberOfPages > 0) {

-    BitsToUnitEnd = FindGuardedMemoryMap (Address, TRUE, &BitMap);

-    ASSERT (BitMap != NULL);

-

-    if (NumberOfPages > BitsToUnitEnd) {

-      // Cross map unit

-      Bits = BitsToUnitEnd;

-    } else {

-      Bits = NumberOfPages;

-    }

-

-    ClearBits (Address, Bits, BitMap);

-

-    NumberOfPages -= Bits;

-    Address       += EFI_PAGES_TO_SIZE (Bits);

-  }

-}

-

-/**

-  Retrieve corresponding bits in bitmap table according to given memory range.

-

-  @param[in]  Address       Memory address to retrieve from.

-  @param[in]  NumberOfPages Number of pages to retrieve.

-

-  @return An integer containing the guarded memory bitmap.

-**/

-UINT64

-GetGuardedMemoryBits (

-  IN EFI_PHYSICAL_ADDRESS  Address,

-  IN UINTN                 NumberOfPages

-  )

-{

-  UINT64  *BitMap;

-  UINTN   Bits;

-  UINT64  Result;

-  UINTN   Shift;

-  UINTN   BitsToUnitEnd;

-

-  ASSERT (NumberOfPages <= GUARDED_HEAP_MAP_ENTRY_BITS);

-

-  Result = 0;

-  Shift  = 0;

-  while (NumberOfPages > 0) {

-    BitsToUnitEnd = FindGuardedMemoryMap (Address, FALSE, &BitMap);

-

-    if (NumberOfPages > BitsToUnitEnd) {

-      // Cross map unit

-      Bits = BitsToUnitEnd;

-    } else {

-      Bits = NumberOfPages;

-    }

-

-    if (BitMap != NULL) {

-      Result |= LShiftU64 (GetBits (Address, Bits, BitMap), Shift);

-    }

-

-    Shift         += Bits;

-    NumberOfPages -= Bits;

-    Address       += EFI_PAGES_TO_SIZE (Bits);

-  }

-

-  return Result;

-}

-

-/**

-  Get bit value in bitmap table for the given address.

-

-  @param[in]  Address     The address to retrieve for.

-

-  @return 1 or 0.

-**/

-UINTN

-EFIAPI

-GetGuardMapBit (

-  IN EFI_PHYSICAL_ADDRESS  Address

-  )

-{

-  UINT64  *GuardMap;

-

-  FindGuardedMemoryMap (Address, FALSE, &GuardMap);

-  if (GuardMap != NULL) {

-    if (RShiftU64 (

-          *GuardMap,

-          GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address)

-          ) & 1)

-    {

-      return 1;

-    }

-  }

-

-  return 0;

-}

-

-/**

-  Check to see if the page at the given address is a Guard page or not.

-

-  @param[in]  Address     The address to check for.

-

-  @return TRUE  The page at Address is a Guard page.

-  @return FALSE The page at Address is not a Guard page.

-**/

-BOOLEAN

-EFIAPI

-IsGuardPage (

-  IN EFI_PHYSICAL_ADDRESS  Address

-  )

-{

-  UINT64  BitMap;

-

-  //

-  // There must be at least one guarded page before and/or after given

-  // address if it's a Guard page. The bitmap pattern should be one of

-  // 001, 100 and 101

-  //

-  BitMap = GetGuardedMemoryBits (Address - EFI_PAGE_SIZE, 3);

-  return ((BitMap == BIT0) || (BitMap == BIT2) || (BitMap == (BIT2 | BIT0)));

-}

-

-/**

-  Check to see if the page at the given address is guarded or not.

-

-  @param[in]  Address     The address to check for.

-

-  @return TRUE  The page at Address is guarded.

-  @return FALSE The page at Address is not guarded.

-**/

-BOOLEAN

-EFIAPI

-IsMemoryGuarded (

-  IN EFI_PHYSICAL_ADDRESS  Address

-  )

-{

-  return (GetGuardMapBit (Address) == 1);

-}

-

-/**

-  Set the page at the given address to be a Guard page.

-

-  This is done by changing the page table attribute to be NOT PRSENT.

-

-  @param[in]  BaseAddress     Page address to Guard at

-

-  @return VOID

-**/

-VOID

-EFIAPI

-SetGuardPage (

-  IN  EFI_PHYSICAL_ADDRESS  BaseAddress

-  )

-{

-  EFI_STATUS  Status;

-

-  if (gCpu == NULL) {

-    return;

-  }

-

-  //

-  // Set flag to make sure allocating memory without GUARD for page table

-  // operation; otherwise infinite loops could be caused.

-  //

-  mOnGuarding = TRUE;

-  //

-  // Note: This might overwrite other attributes needed by other features,

-  // such as NX memory protection.

-  //

-  Status = gCpu->SetMemoryAttributes (gCpu, BaseAddress, EFI_PAGE_SIZE, EFI_MEMORY_RP);

-  ASSERT_EFI_ERROR (Status);

-  mOnGuarding = FALSE;

-}

-

-/**

-  Unset the Guard page at the given address to the normal memory.

-

-  This is done by changing the page table attribute to be PRSENT.

-

-  @param[in]  BaseAddress     Page address to Guard at.

-

-  @return VOID.

-**/

-VOID

-EFIAPI

-UnsetGuardPage (

-  IN  EFI_PHYSICAL_ADDRESS  BaseAddress

-  )

-{

-  UINT64      Attributes;

-  EFI_STATUS  Status;

-

-  if (gCpu == NULL) {

-    return;

-  }

-

-  //

-  // Once the Guard page is unset, it will be freed back to memory pool. NX

-  // memory protection must be restored for this page if NX is enabled for free

-  // memory.

-  //

-  Attributes = 0;

-  if ((PcdGet64 (PcdDxeNxMemoryProtectionPolicy) & (1 << EfiConventionalMemory)) != 0) {

-    Attributes |= EFI_MEMORY_XP;

-  }

-

-  //

-  // Set flag to make sure allocating memory without GUARD for page table

-  // operation; otherwise infinite loops could be caused.

-  //

-  mOnGuarding = TRUE;

-  //

-  // Note: This might overwrite other attributes needed by other features,

-  // such as memory protection (NX). Please make sure they are not enabled

-  // at the same time.

-  //

-  Status = gCpu->SetMemoryAttributes (gCpu, BaseAddress, EFI_PAGE_SIZE, Attributes);

-  ASSERT_EFI_ERROR (Status);

-  mOnGuarding = FALSE;

-}

-

-/**

-  Check to see if the memory at the given address should be guarded or not.

-

-  @param[in]  MemoryType      Memory type to check.

-  @param[in]  AllocateType    Allocation type to check.

-  @param[in]  PageOrPool      Indicate a page allocation or pool allocation.

-

-

-  @return TRUE  The given type of memory should be guarded.

-  @return FALSE The given type of memory should not be guarded.

-**/

-BOOLEAN

-IsMemoryTypeToGuard (

-  IN EFI_MEMORY_TYPE    MemoryType,

-  IN EFI_ALLOCATE_TYPE  AllocateType,

-  IN UINT8              PageOrPool

-  )

-{

-  UINT64  TestBit;

-  UINT64  ConfigBit;

-

-  if (AllocateType == AllocateAddress) {

-    return FALSE;

-  }

-

-  if ((PcdGet8 (PcdHeapGuardPropertyMask) & PageOrPool) == 0) {

-    return FALSE;

-  }

-

-  if (PageOrPool == GUARD_HEAP_TYPE_POOL) {

-    ConfigBit = PcdGet64 (PcdHeapGuardPoolType);

-  } else if (PageOrPool == GUARD_HEAP_TYPE_PAGE) {

-    ConfigBit = PcdGet64 (PcdHeapGuardPageType);

-  } else {

-    ConfigBit = (UINT64)-1;

-  }

-

-  if ((UINT32)MemoryType >= MEMORY_TYPE_OS_RESERVED_MIN) {

-    TestBit = BIT63;

-  } else if ((UINT32)MemoryType >= MEMORY_TYPE_OEM_RESERVED_MIN) {

-    TestBit = BIT62;

-  } else if (MemoryType < EfiMaxMemoryType) {

-    TestBit = LShiftU64 (1, MemoryType);

-  } else if (MemoryType == EfiMaxMemoryType) {

-    TestBit = (UINT64)-1;

-  } else {

-    TestBit = 0;

-  }

-

-  return ((ConfigBit & TestBit) != 0);

-}

-

-/**

-  Check to see if the pool at the given address should be guarded or not.

-

-  @param[in]  MemoryType      Pool type to check.

-

-

-  @return TRUE  The given type of pool should be guarded.

-  @return FALSE The given type of pool should not be guarded.

-**/

-BOOLEAN

-IsPoolTypeToGuard (

-  IN EFI_MEMORY_TYPE  MemoryType

-  )

-{

-  return IsMemoryTypeToGuard (

-           MemoryType,

-           AllocateAnyPages,

-           GUARD_HEAP_TYPE_POOL

-           );

-}

-

-/**

-  Check to see if the page at the given address should be guarded or not.

-

-  @param[in]  MemoryType      Page type to check.

-  @param[in]  AllocateType    Allocation type to check.

-

-  @return TRUE  The given type of page should be guarded.

-  @return FALSE The given type of page should not be guarded.

-**/

-BOOLEAN

-IsPageTypeToGuard (

-  IN EFI_MEMORY_TYPE    MemoryType,

-  IN EFI_ALLOCATE_TYPE  AllocateType

-  )

-{

-  return IsMemoryTypeToGuard (MemoryType, AllocateType, GUARD_HEAP_TYPE_PAGE);

-}

-

-/**

-  Check to see if the heap guard is enabled for page and/or pool allocation.

-

-  @param[in]  GuardType   Specify the sub-type(s) of Heap Guard.

-

-  @return TRUE/FALSE.

-**/

-BOOLEAN

-IsHeapGuardEnabled (

-  UINT8  GuardType

-  )

-{

-  return IsMemoryTypeToGuard (EfiMaxMemoryType, AllocateAnyPages, GuardType);

-}

-

-/**

-  Set head Guard and tail Guard for the given memory range.

-

-  @param[in]  Memory          Base address of memory to set guard for.

-  @param[in]  NumberOfPages   Memory size in pages.

-

-  @return VOID

-**/

-VOID

-SetGuardForMemory (

-  IN EFI_PHYSICAL_ADDRESS  Memory,

-  IN UINTN                 NumberOfPages

-  )

-{

-  EFI_PHYSICAL_ADDRESS  GuardPage;

-

-  //

-  // Set tail Guard

-  //

-  GuardPage = Memory + EFI_PAGES_TO_SIZE (NumberOfPages);

-  if (!IsGuardPage (GuardPage)) {

-    SetGuardPage (GuardPage);

-  }

-

-  // Set head Guard

-  GuardPage = Memory - EFI_PAGES_TO_SIZE (1);

-  if (!IsGuardPage (GuardPage)) {

-    SetGuardPage (GuardPage);

-  }

-

-  //

-  // Mark the memory range as Guarded

-  //

-  SetGuardedMemoryBits (Memory, NumberOfPages);

-}

-

-/**

-  Unset head Guard and tail Guard for the given memory range.

-

-  @param[in]  Memory          Base address of memory to unset guard for.

-  @param[in]  NumberOfPages   Memory size in pages.

-

-  @return VOID

-**/

-VOID

-UnsetGuardForMemory (

-  IN EFI_PHYSICAL_ADDRESS  Memory,

-  IN UINTN                 NumberOfPages

-  )

-{

-  EFI_PHYSICAL_ADDRESS  GuardPage;

-  UINT64                GuardBitmap;

-

-  if (NumberOfPages == 0) {

-    return;

-  }

-

-  //

-  // Head Guard must be one page before, if any.

-  //

-  //          MSB-> 1     0 <-LSB

-  //          -------------------

-  //  Head Guard -> 0     1 -> Don't free Head Guard  (shared Guard)

-  //  Head Guard -> 0     0 -> Free Head Guard either (not shared Guard)

-  //                1     X -> Don't free first page  (need a new Guard)

-  //                           (it'll be turned into a Guard page later)

-  //          -------------------

-  //      Start -> -1    -2

-  //

-  GuardPage   = Memory - EFI_PAGES_TO_SIZE (1);

-  GuardBitmap = GetGuardedMemoryBits (Memory - EFI_PAGES_TO_SIZE (2), 2);

-  if ((GuardBitmap & BIT1) == 0) {

-    //

-    // Head Guard exists.

-    //

-    if ((GuardBitmap & BIT0) == 0) {

-      //

-      // If the head Guard is not a tail Guard of adjacent memory block,

-      // unset it.

-      //

-      UnsetGuardPage (GuardPage);

-    }

-  } else {

-    //

-    // Pages before memory to free are still in Guard. It's a partial free

-    // case. Turn first page of memory block to free into a new Guard.

-    //

-    SetGuardPage (Memory);

-  }

-

-  //

-  // Tail Guard must be the page after this memory block to free, if any.

-  //

-  //   MSB-> 1     0 <-LSB

-  //  --------------------

-  //         1     0 <- Tail Guard -> Don't free Tail Guard  (shared Guard)

-  //         0     0 <- Tail Guard -> Free Tail Guard either (not shared Guard)

-  //         X     1               -> Don't free last page   (need a new Guard)

-  //                                 (it'll be turned into a Guard page later)

-  //  --------------------

-  //        +1    +0 <- End

-  //

-  GuardPage   = Memory + EFI_PAGES_TO_SIZE (NumberOfPages);

-  GuardBitmap = GetGuardedMemoryBits (GuardPage, 2);

-  if ((GuardBitmap & BIT0) == 0) {

-    //

-    // Tail Guard exists.

-    //

-    if ((GuardBitmap & BIT1) == 0) {

-      //

-      // If the tail Guard is not a head Guard of adjacent memory block,

-      // free it; otherwise, keep it.

-      //

-      UnsetGuardPage (GuardPage);

-    }

-  } else {

-    //

-    // Pages after memory to free are still in Guard. It's a partial free

-    // case. We need to keep one page to be a head Guard.

-    //

-    SetGuardPage (GuardPage - EFI_PAGES_TO_SIZE (1));

-  }

-

-  //

-  // No matter what, we just clear the mark of the Guarded memory.

-  //

-  ClearGuardedMemoryBits (Memory, NumberOfPages);

-}

-

-/**

-  Adjust address of free memory according to existing and/or required Guard.

-

-  This function will check if there're existing Guard pages of adjacent

-  memory blocks, and try to use it as the Guard page of the memory to be

-  allocated.

-

-  @param[in]  Start           Start address of free memory block.

-  @param[in]  Size            Size of free memory block.

-  @param[in]  SizeRequested   Size of memory to allocate.

-

-  @return The end address of memory block found.

-  @return 0 if no enough space for the required size of memory and its Guard.

-**/

-UINT64

-AdjustMemoryS (

-  IN UINT64  Start,

-  IN UINT64  Size,

-  IN UINT64  SizeRequested

-  )

-{

-  UINT64  Target;

-

-  //

-  // UEFI spec requires that allocated pool must be 8-byte aligned. If it's

-  // indicated to put the pool near the Tail Guard, we need extra bytes to

-  // make sure alignment of the returned pool address.

-  //

-  if ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) == 0) {

-    SizeRequested = ALIGN_VALUE (SizeRequested, 8);

-  }

-

-  Target = Start + Size - SizeRequested;

-  ASSERT (Target >= Start);

-  if (Target == 0) {

-    return 0;

-  }

-

-  if (!IsGuardPage (Start + Size)) {

-    // No Guard at tail to share. One more page is needed.

-    Target -= EFI_PAGES_TO_SIZE (1);

-  }

-

-  // Out of range?

-  if (Target < Start) {

-    return 0;

-  }

-

-  // At the edge?

-  if (Target == Start) {

-    if (!IsGuardPage (Target - EFI_PAGES_TO_SIZE (1))) {

-      // No enough space for a new head Guard if no Guard at head to share.

-      return 0;

-    }

-  }

-

-  // OK, we have enough pages for memory and its Guards. Return the End of the

-  // free space.

-  return Target + SizeRequested - 1;

-}

-

-/**

-  Adjust the start address and number of pages to free according to Guard.

-

-  The purpose of this function is to keep the shared Guard page with adjacent

-  memory block if it's still in guard, or free it if no more sharing. Another

-  is to reserve pages as Guard pages in partial page free situation.

-

-  @param[in,out]  Memory          Base address of memory to free.

-  @param[in,out]  NumberOfPages   Size of memory to free.

-

-  @return VOID.

-**/

-VOID

-AdjustMemoryF (

-  IN OUT EFI_PHYSICAL_ADDRESS  *Memory,

-  IN OUT UINTN                 *NumberOfPages

-  )

-{

-  EFI_PHYSICAL_ADDRESS  Start;

-  EFI_PHYSICAL_ADDRESS  MemoryToTest;

-  UINTN                 PagesToFree;

-  UINT64                GuardBitmap;

-

-  if ((Memory == NULL) || (NumberOfPages == NULL) || (*NumberOfPages == 0)) {

-    return;

-  }

-

-  Start       = *Memory;

-  PagesToFree = *NumberOfPages;

-

-  //

-  // Head Guard must be one page before, if any.

-  //

-  //          MSB-> 1     0 <-LSB

-  //          -------------------

-  //  Head Guard -> 0     1 -> Don't free Head Guard  (shared Guard)

-  //  Head Guard -> 0     0 -> Free Head Guard either (not shared Guard)

-  //                1     X -> Don't free first page  (need a new Guard)

-  //                           (it'll be turned into a Guard page later)

-  //          -------------------

-  //      Start -> -1    -2

-  //

-  MemoryToTest = Start - EFI_PAGES_TO_SIZE (2);

-  GuardBitmap  = GetGuardedMemoryBits (MemoryToTest, 2);

-  if ((GuardBitmap & BIT1) == 0) {

-    //

-    // Head Guard exists.

-    //

-    if ((GuardBitmap & BIT0) == 0) {

-      //

-      // If the head Guard is not a tail Guard of adjacent memory block,

-      // free it; otherwise, keep it.

-      //

-      Start       -= EFI_PAGES_TO_SIZE (1);

-      PagesToFree += 1;

-    }

-  } else {

-    //

-    // No Head Guard, and pages before memory to free are still in Guard. It's a

-    // partial free case. We need to keep one page to be a tail Guard.

-    //

-    Start       += EFI_PAGES_TO_SIZE (1);

-    PagesToFree -= 1;

-  }

-

-  //

-  // Tail Guard must be the page after this memory block to free, if any.

-  //

-  //   MSB-> 1     0 <-LSB

-  //  --------------------

-  //         1     0 <- Tail Guard -> Don't free Tail Guard  (shared Guard)

-  //         0     0 <- Tail Guard -> Free Tail Guard either (not shared Guard)

-  //         X     1               -> Don't free last page   (need a new Guard)

-  //                                 (it'll be turned into a Guard page later)

-  //  --------------------

-  //        +1    +0 <- End

-  //

-  MemoryToTest = Start + EFI_PAGES_TO_SIZE (PagesToFree);

-  GuardBitmap  = GetGuardedMemoryBits (MemoryToTest, 2);

-  if ((GuardBitmap & BIT0) == 0) {

-    //

-    // Tail Guard exists.

-    //

-    if ((GuardBitmap & BIT1) == 0) {

-      //

-      // If the tail Guard is not a head Guard of adjacent memory block,

-      // free it; otherwise, keep it.

-      //

-      PagesToFree += 1;

-    }

-  } else if (PagesToFree > 0) {

-    //

-    // No Tail Guard, and pages after memory to free are still in Guard. It's a

-    // partial free case. We need to keep one page to be a head Guard.

-    //

-    PagesToFree -= 1;

-  }

-

-  *Memory        = Start;

-  *NumberOfPages = PagesToFree;

-}

-

-/**

-  Adjust the base and number of pages to really allocate according to Guard.

-

-  @param[in,out]  Memory          Base address of free memory.

-  @param[in,out]  NumberOfPages   Size of memory to allocate.

-

-  @return VOID.

-**/

-VOID

-AdjustMemoryA (

-  IN OUT EFI_PHYSICAL_ADDRESS  *Memory,

-  IN OUT UINTN                 *NumberOfPages

-  )

-{

-  //

-  // FindFreePages() has already taken the Guard into account. It's safe to

-  // adjust the start address and/or number of pages here, to make sure that

-  // the Guards are also "allocated".

-  //

-  if (!IsGuardPage (*Memory + EFI_PAGES_TO_SIZE (*NumberOfPages))) {

-    // No tail Guard, add one.

-    *NumberOfPages += 1;

-  }

-

-  if (!IsGuardPage (*Memory - EFI_PAGE_SIZE)) {

-    // No head Guard, add one.

-    *Memory        -= EFI_PAGE_SIZE;

-    *NumberOfPages += 1;

-  }

-}

-

-/**

-  Adjust the pool head position to make sure the Guard page is adjavent to

-  pool tail or pool head.

-

-  @param[in]  Memory    Base address of memory allocated.

-  @param[in]  NoPages   Number of pages actually allocated.

-  @param[in]  Size      Size of memory requested.

-                        (plus pool head/tail overhead)

-

-  @return Address of pool head.

-**/

-VOID *

-AdjustPoolHeadA (

-  IN EFI_PHYSICAL_ADDRESS  Memory,

-  IN UINTN                 NoPages,

-  IN UINTN                 Size

-  )

-{

-  if ((Memory == 0) || ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0)) {

-    //

-    // Pool head is put near the head Guard

-    //

-    return (VOID *)(UINTN)Memory;

-  }

-

-  //

-  // Pool head is put near the tail Guard

-  //

-  Size = ALIGN_VALUE (Size, 8);

-  return (VOID *)(UINTN)(Memory + EFI_PAGES_TO_SIZE (NoPages) - Size);

-}

-

-/**

-  Get the page base address according to pool head address.

-

-  @param[in]  Memory    Head address of pool to free.

-  @param[in]  NoPages   Number of pages actually allocated.

-  @param[in]  Size      Size of memory requested.

-                        (plus pool head/tail overhead)

-

-  @return Address of pool head.

-**/

-VOID *

-AdjustPoolHeadF (

-  IN EFI_PHYSICAL_ADDRESS  Memory,

-  IN UINTN                 NoPages,

-  IN UINTN                 Size

-  )

-{

-  if ((Memory == 0) || ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0)) {

-    //

-    // Pool head is put near the head Guard

-    //

-    return (VOID *)(UINTN)Memory;

-  }

-

-  //

-  // Pool head is put near the tail Guard. We need to exactly undo the addition done in AdjustPoolHeadA

-  // because we may not have allocated the pool head on the first allocated page, since we are aligned to

-  // the tail and on some architectures, the runtime page allocation granularity is > one page. So we allocate

-  // more pages than we need and put the pool head somewhere past the first page.

-  //

-  return (VOID *)(UINTN)(Memory + Size - EFI_PAGES_TO_SIZE (NoPages));

-}

-

-/**

-  Allocate or free guarded memory.

-

-  @param[in]  Start           Start address of memory to allocate or free.

-  @param[in]  NumberOfPages   Memory size in pages.

-  @param[in]  NewType         Memory type to convert to.

-

-  @return VOID.

-**/

-EFI_STATUS

-CoreConvertPagesWithGuard (

-  IN UINT64           Start,

-  IN UINTN            NumberOfPages,

-  IN EFI_MEMORY_TYPE  NewType

-  )

-{

-  UINT64  OldStart;

-  UINTN   OldPages;

-

-  if (NewType == EfiConventionalMemory) {

-    OldStart = Start;

-    OldPages = NumberOfPages;

-

-    AdjustMemoryF (&Start, &NumberOfPages);

-    //

-    // It's safe to unset Guard page inside memory lock because there should

-    // be no memory allocation occurred in updating memory page attribute at

-    // this point. And unsetting Guard page before free will prevent Guard

-    // page just freed back to pool from being allocated right away before

-    // marking it usable (from non-present to present).

-    //

-    UnsetGuardForMemory (OldStart, OldPages);

-    if (NumberOfPages == 0) {

-      return EFI_SUCCESS;

-    }

-  } else {

-    AdjustMemoryA (&Start, &NumberOfPages);

-  }

-

-  return CoreConvertPages (Start, NumberOfPages, NewType);

-}

-

-/**

-  Set all Guard pages which cannot be set before CPU Arch Protocol installed.

-**/

-VOID

-SetAllGuardPages (

-  VOID

-  )

-{

-  UINTN    Entries[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINTN    Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINTN    Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64   Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64   Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64   TableEntry;

-  UINT64   Address;

-  UINT64   GuardPage;

-  INTN     Level;

-  UINTN    Index;

-  BOOLEAN  OnGuarding;

-

-  if ((mGuardedMemoryMap == 0) ||

-      (mMapLevel == 0) ||

-      (mMapLevel > GUARDED_HEAP_MAP_TABLE_DEPTH))

-  {

-    return;

-  }

-

-  CopyMem (Entries, mLevelMask, sizeof (Entries));

-  CopyMem (Shifts, mLevelShift, sizeof (Shifts));

-

-  SetMem (Tables, sizeof (Tables), 0);

-  SetMem (Addresses, sizeof (Addresses), 0);

-  SetMem (Indices, sizeof (Indices), 0);

-

-  Level         = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;

-  Tables[Level] = mGuardedMemoryMap;

-  Address       = 0;

-  OnGuarding    = FALSE;

-

-  DEBUG_CODE (

-    DumpGuardedMemoryBitmap ();

-    );

-

-  while (TRUE) {

-    if (Indices[Level] > Entries[Level]) {

-      Tables[Level] = 0;

-      Level        -= 1;

-    } else {

-      TableEntry = ((UINT64 *)(UINTN)(Tables[Level]))[Indices[Level]];

-      Address    = Addresses[Level];

-

-      if (TableEntry == 0) {

-        OnGuarding = FALSE;

-      } else if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {

-        Level           += 1;

-        Tables[Level]    = TableEntry;

-        Addresses[Level] = Address;

-        Indices[Level]   = 0;

-

-        continue;

-      } else {

-        Index = 0;

-        while (Index < GUARDED_HEAP_MAP_ENTRY_BITS) {

-          if ((TableEntry & 1) == 1) {

-            if (OnGuarding) {

-              GuardPage = 0;

-            } else {

-              GuardPage = Address - EFI_PAGE_SIZE;

-            }

-

-            OnGuarding = TRUE;

-          } else {

-            if (OnGuarding) {

-              GuardPage = Address;

-            } else {

-              GuardPage = 0;

-            }

-

-            OnGuarding = FALSE;

-          }

-

-          if (GuardPage != 0) {

-            SetGuardPage (GuardPage);

-          }

-

-          if (TableEntry == 0) {

-            break;

-          }

-

-          TableEntry = RShiftU64 (TableEntry, 1);

-          Address   += EFI_PAGE_SIZE;

-          Index     += 1;

-        }

-      }

-    }

-

-    if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) {

-      break;

-    }

-

-    Indices[Level]  += 1;

-    Address          = (Level == 0) ? 0 : Addresses[Level - 1];

-    Addresses[Level] = Address | LShiftU64 (Indices[Level], Shifts[Level]);

-  }

-}

-

-/**

-  Find the address of top-most guarded free page.

-

-  @param[out]  Address    Start address of top-most guarded free page.

-

-  @return VOID.

-**/

-VOID

-GetLastGuardedFreePageAddress (

-  OUT EFI_PHYSICAL_ADDRESS  *Address

-  )

-{

-  EFI_PHYSICAL_ADDRESS  AddressGranularity;

-  EFI_PHYSICAL_ADDRESS  BaseAddress;

-  UINTN                 Level;

-  UINT64                Map;

-  INTN                  Index;

-

-  ASSERT (mMapLevel >= 1);

-

-  BaseAddress = 0;

-  Map         = mGuardedMemoryMap;

-  for (Level = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;

-       Level < GUARDED_HEAP_MAP_TABLE_DEPTH;

-       ++Level)

-  {

-    AddressGranularity = LShiftU64 (1, mLevelShift[Level]);

-

-    //

-    // Find the non-NULL entry at largest index.

-    //

-    for (Index = (INTN)mLevelMask[Level]; Index >= 0; --Index) {

-      if (((UINT64 *)(UINTN)Map)[Index] != 0) {

-        BaseAddress += MultU64x32 (AddressGranularity, (UINT32)Index);

-        Map          = ((UINT64 *)(UINTN)Map)[Index];

-        break;

-      }

-    }

-  }

-

-  //

-  // Find the non-zero MSB then get the page address.

-  //

-  while (Map != 0) {

-    Map          = RShiftU64 (Map, 1);

-    BaseAddress += EFI_PAGES_TO_SIZE (1);

-  }

-

-  *Address = BaseAddress;

-}

-

-/**

-  Record freed pages.

-

-  @param[in]  BaseAddress   Base address of just freed pages.

-  @param[in]  Pages         Number of freed pages.

-

-  @return VOID.

-**/

-VOID

-MarkFreedPages (

-  IN EFI_PHYSICAL_ADDRESS  BaseAddress,

-  IN UINTN                 Pages

-  )

-{

-  SetGuardedMemoryBits (BaseAddress, Pages);

-}

-

-/**

-  Record freed pages as well as mark them as not-present.

-

-  @param[in]  BaseAddress   Base address of just freed pages.

-  @param[in]  Pages         Number of freed pages.

-

-  @return VOID.

-**/

-VOID

-EFIAPI

-GuardFreedPages (

-  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,

-  IN  UINTN                 Pages

-  )

-{

-  EFI_STATUS  Status;

-

-  //

-  // Legacy memory lower than 1MB might be accessed with no allocation. Leave

-  // them alone.

-  //

-  if (BaseAddress < BASE_1MB) {

-    return;

-  }

-

-  MarkFreedPages (BaseAddress, Pages);

-  if (gCpu != NULL) {

-    //

-    // Set flag to make sure allocating memory without GUARD for page table

-    // operation; otherwise infinite loops could be caused.

-    //

-    mOnGuarding = TRUE;

-    //

-    // Note: This might overwrite other attributes needed by other features,

-    // such as NX memory protection.

-    //

-    Status = gCpu->SetMemoryAttributes (

-                     gCpu,

-                     BaseAddress,

-                     EFI_PAGES_TO_SIZE (Pages),

-                     EFI_MEMORY_RP

-                     );

-    //

-    // Normally we should ASSERT the returned Status. But there might be memory

-    // alloc/free involved in SetMemoryAttributes(), which might fail this

-    // calling. It's rare case so it's OK to let a few tiny holes be not-guarded.

-    //

-    if (EFI_ERROR (Status)) {

-      DEBUG ((DEBUG_WARN, "Failed to guard freed pages: %p (%lu)\n", BaseAddress, (UINT64)Pages));

-    }

-

-    mOnGuarding = FALSE;

-  }

-}

-

-/**

-  Record freed pages as well as mark them as not-present, if enabled.

-

-  @param[in]  BaseAddress   Base address of just freed pages.

-  @param[in]  Pages         Number of freed pages.

-

-  @return VOID.

-**/

-VOID

-EFIAPI

-GuardFreedPagesChecked (

-  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,

-  IN  UINTN                 Pages

-  )

-{

-  if (IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED)) {

-    GuardFreedPages (BaseAddress, Pages);

-  }

-}

-

-/**

-  Mark all pages freed before CPU Arch Protocol as not-present.

-

-**/

-VOID

-GuardAllFreedPages (

-  VOID

-  )

-{

-  UINTN   Entries[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINTN   Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINTN   Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64  Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64  Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64  TableEntry;

-  UINT64  Address;

-  UINT64  GuardPage;

-  INTN    Level;

-  UINT64  BitIndex;

-  UINTN   GuardPageNumber;

-

-  if ((mGuardedMemoryMap == 0) ||

-      (mMapLevel == 0) ||

-      (mMapLevel > GUARDED_HEAP_MAP_TABLE_DEPTH))

-  {

-    return;

-  }

-

-  CopyMem (Entries, mLevelMask, sizeof (Entries));

-  CopyMem (Shifts, mLevelShift, sizeof (Shifts));

-

-  SetMem (Tables, sizeof (Tables), 0);

-  SetMem (Addresses, sizeof (Addresses), 0);

-  SetMem (Indices, sizeof (Indices), 0);

-

-  Level           = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;

-  Tables[Level]   = mGuardedMemoryMap;

-  Address         = 0;

-  GuardPage       = (UINT64)-1;

-  GuardPageNumber = 0;

-

-  while (TRUE) {

-    if (Indices[Level] > Entries[Level]) {

-      Tables[Level] = 0;

-      Level        -= 1;

-    } else {

-      TableEntry = ((UINT64 *)(UINTN)(Tables[Level]))[Indices[Level]];

-      Address    = Addresses[Level];

-

-      if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {

-        Level           += 1;

-        Tables[Level]    = TableEntry;

-        Addresses[Level] = Address;

-        Indices[Level]   = 0;

-

-        continue;

-      } else {

-        BitIndex = 1;

-        while (BitIndex != 0) {

-          if ((TableEntry & BitIndex) != 0) {

-            if (GuardPage == (UINT64)-1) {

-              GuardPage = Address;

-            }

-

-            ++GuardPageNumber;

-          } else if (GuardPageNumber > 0) {

-            GuardFreedPages (GuardPage, GuardPageNumber);

-            GuardPageNumber = 0;

-            GuardPage       = (UINT64)-1;

-          }

-

-          if (TableEntry == 0) {

-            break;

-          }

-

-          Address += EFI_PAGES_TO_SIZE (1);

-          BitIndex = LShiftU64 (BitIndex, 1);

-        }

-      }

-    }

-

-    if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) {

-      break;

-    }

-

-    Indices[Level]  += 1;

-    Address          = (Level == 0) ? 0 : Addresses[Level - 1];

-    Addresses[Level] = Address | LShiftU64 (Indices[Level], Shifts[Level]);

-  }

-

-  //

-  // Update the maximum address of freed page which can be used for memory

-  // promotion upon out-of-memory-space.

-  //

-  GetLastGuardedFreePageAddress (&Address);

-  if (Address != 0) {

-    mLastPromotedPage = Address;

-  }

-}

-

-/**

-  This function checks to see if the given memory map descriptor in a memory map

-  can be merged with any guarded free pages.

-

-  @param  MemoryMapEntry    A pointer to a descriptor in MemoryMap.

-  @param  MaxAddress        Maximum address to stop the merge.

-

-  @return VOID

-

-**/

-VOID

-MergeGuardPages (

-  IN EFI_MEMORY_DESCRIPTOR  *MemoryMapEntry,

-  IN EFI_PHYSICAL_ADDRESS   MaxAddress

-  )

-{

-  EFI_PHYSICAL_ADDRESS  EndAddress;

-  UINT64                Bitmap;

-  INTN                  Pages;

-

-  if (!IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED) ||

-      (MemoryMapEntry->Type >= EfiMemoryMappedIO))

-  {

-    return;

-  }

-

-  Bitmap = 0;

-  Pages  = EFI_SIZE_TO_PAGES ((UINTN)(MaxAddress - MemoryMapEntry->PhysicalStart));

-  Pages -= (INTN)MemoryMapEntry->NumberOfPages;

-  while (Pages > 0) {

-    if (Bitmap == 0) {

-      EndAddress = MemoryMapEntry->PhysicalStart +

-                   EFI_PAGES_TO_SIZE ((UINTN)MemoryMapEntry->NumberOfPages);

-      Bitmap = GetGuardedMemoryBits (EndAddress, GUARDED_HEAP_MAP_ENTRY_BITS);

-    }

-

-    if ((Bitmap & 1) == 0) {

-      break;

-    }

-

-    Pages--;

-    MemoryMapEntry->NumberOfPages++;

-    Bitmap = RShiftU64 (Bitmap, 1);

-  }

-}

-

-/**

-  Put part (at most 64 pages a time) guarded free pages back to free page pool.

-

-  Freed memory guard is used to detect Use-After-Free (UAF) memory issue, which

-  makes use of 'Used then throw away' way to detect any illegal access to freed

-  memory. The thrown-away memory will be marked as not-present so that any access

-  to those memory (after free) will be caught by page-fault exception.

-

-  The problem is that this will consume lots of memory space. Once no memory

-  left in pool to allocate, we have to restore part of the freed pages to their

-  normal function. Otherwise the whole system will stop functioning.

-

-  @param  StartAddress    Start address of promoted memory.

-  @param  EndAddress      End address of promoted memory.

-

-  @return TRUE    Succeeded to promote memory.

-  @return FALSE   No free memory found.

-

-**/

-BOOLEAN

-PromoteGuardedFreePages (

-  OUT EFI_PHYSICAL_ADDRESS  *StartAddress,

-  OUT EFI_PHYSICAL_ADDRESS  *EndAddress

-  )

-{

-  EFI_STATUS            Status;

-  UINTN                 AvailablePages;

-  UINT64                Bitmap;

-  EFI_PHYSICAL_ADDRESS  Start;

-

-  if (!IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED)) {

-    return FALSE;

-  }

-

-  //

-  // Similar to memory allocation service, always search the freed pages in

-  // descending direction.

-  //

-  Start          = mLastPromotedPage;

-  AvailablePages = 0;

-  while (AvailablePages == 0) {

-    Start -= EFI_PAGES_TO_SIZE (GUARDED_HEAP_MAP_ENTRY_BITS);

-    //

-    // If the address wraps around, try the really freed pages at top.

-    //

-    if (Start > mLastPromotedPage) {

-      GetLastGuardedFreePageAddress (&Start);

-      ASSERT (Start != 0);

-      Start -= EFI_PAGES_TO_SIZE (GUARDED_HEAP_MAP_ENTRY_BITS);

-    }

-

-    Bitmap = GetGuardedMemoryBits (Start, GUARDED_HEAP_MAP_ENTRY_BITS);

-    while (Bitmap > 0) {

-      if ((Bitmap & 1) != 0) {

-        ++AvailablePages;

-      } else if (AvailablePages == 0) {

-        Start += EFI_PAGES_TO_SIZE (1);

-      } else {

-        break;

-      }

-

-      Bitmap = RShiftU64 (Bitmap, 1);

-    }

-  }

-

-  if (AvailablePages != 0) {

-    DEBUG ((DEBUG_INFO, "Promoted pages: %lX (%lx)\r\n", Start, (UINT64)AvailablePages));

-    ClearGuardedMemoryBits (Start, AvailablePages);

-

-    if (gCpu != NULL) {

-      //

-      // Set flag to make sure allocating memory without GUARD for page table

-      // operation; otherwise infinite loops could be caused.

-      //

-      mOnGuarding = TRUE;

-      Status      = gCpu->SetMemoryAttributes (gCpu, Start, EFI_PAGES_TO_SIZE (AvailablePages), 0);

-      ASSERT_EFI_ERROR (Status);

-      mOnGuarding = FALSE;

-    }

-

-    mLastPromotedPage = Start;

-    *StartAddress     = Start;

-    *EndAddress       = Start + EFI_PAGES_TO_SIZE (AvailablePages) - 1;

-    return TRUE;

-  }

-

-  return FALSE;

-}

-

-/**

-  Notify function used to set all Guard pages before CPU Arch Protocol installed.

-**/

-VOID

-HeapGuardCpuArchProtocolNotify (

-  VOID

-  )

-{

-  ASSERT (gCpu != NULL);

-

-  if (IsHeapGuardEnabled (GUARD_HEAP_TYPE_PAGE|GUARD_HEAP_TYPE_POOL) &&

-      IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED))

-  {

-    DEBUG ((DEBUG_ERROR, "Heap guard and freed memory guard cannot be enabled at the same time.\n"));

-    CpuDeadLoop ();

-  }

-

-  if (IsHeapGuardEnabled (GUARD_HEAP_TYPE_PAGE|GUARD_HEAP_TYPE_POOL)) {

-    SetAllGuardPages ();

-  }

-

-  if (IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED)) {

-    GuardAllFreedPages ();

-  }

-}

-

-/**

-  Helper function to convert a UINT64 value in binary to a string.

-

-  @param[in]  Value       Value of a UINT64 integer.

-  @param[out]  BinString   String buffer to contain the conversion result.

-

-  @return VOID.

-**/

-VOID

-Uint64ToBinString (

-  IN  UINT64  Value,

-  OUT CHAR8   *BinString

-  )

-{

-  UINTN  Index;

-

-  if (BinString == NULL) {

-    return;

-  }

-

-  for (Index = 64; Index > 0; --Index) {

-    BinString[Index - 1] = '0' + (Value & 1);

-    Value                = RShiftU64 (Value, 1);

-  }

-

-  BinString[64] = '\0';

-}

-

-/**

-  Dump the guarded memory bit map.

-**/

-VOID

-EFIAPI

-DumpGuardedMemoryBitmap (

-  VOID

-  )

-{

-  UINTN   Entries[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINTN   Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINTN   Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64  Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64  Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];

-  UINT64  TableEntry;

-  UINT64  Address;

-  INTN    Level;

-  UINTN   RepeatZero;

-  CHAR8   String[GUARDED_HEAP_MAP_ENTRY_BITS + 1];

-  CHAR8   *Ruler1;

-  CHAR8   *Ruler2;

-

-  if (!IsHeapGuardEnabled (GUARD_HEAP_TYPE_ALL)) {

-    return;

-  }

-

-  if ((mGuardedMemoryMap == 0) ||

-      (mMapLevel == 0) ||

-      (mMapLevel > GUARDED_HEAP_MAP_TABLE_DEPTH))

-  {

-    return;

-  }

-

-  Ruler1 = "               3               2               1               0";

-  Ruler2 = "FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210";

-

-  DEBUG ((

-    HEAP_GUARD_DEBUG_LEVEL,

-    "============================="

-    " Guarded Memory Bitmap "

-    "==============================\r\n"

-    ));

-  DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "                  %a\r\n", Ruler1));

-  DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "                  %a\r\n", Ruler2));

-

-  CopyMem (Entries, mLevelMask, sizeof (Entries));

-  CopyMem (Shifts, mLevelShift, sizeof (Shifts));

-

-  SetMem (Indices, sizeof (Indices), 0);

-  SetMem (Tables, sizeof (Tables), 0);

-  SetMem (Addresses, sizeof (Addresses), 0);

-

-  Level         = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;

-  Tables[Level] = mGuardedMemoryMap;

-  Address       = 0;

-  RepeatZero    = 0;

-

-  while (TRUE) {

-    if (Indices[Level] > Entries[Level]) {

-      Tables[Level] = 0;

-      Level        -= 1;

-      RepeatZero    = 0;

-

-      DEBUG ((

-        HEAP_GUARD_DEBUG_LEVEL,

-        "========================================="

-        "=========================================\r\n"

-        ));

-    } else {

-      TableEntry = ((UINT64 *)(UINTN)Tables[Level])[Indices[Level]];

-      Address    = Addresses[Level];

-

-      if (TableEntry == 0) {

-        if (Level == GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {

-          if (RepeatZero == 0) {

-            Uint64ToBinString (TableEntry, String);

-            DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "%016lx: %a\r\n", Address, String));

-          } else if (RepeatZero == 1) {

-            DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "...             : ...\r\n"));

-          }

-

-          RepeatZero += 1;

-        }

-      } else if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {

-        Level           += 1;

-        Tables[Level]    = TableEntry;

-        Addresses[Level] = Address;

-        Indices[Level]   = 0;

-        RepeatZero       = 0;

-

-        continue;

-      } else {

-        RepeatZero = 0;

-        Uint64ToBinString (TableEntry, String);

-        DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "%016lx: %a\r\n", Address, String));

-      }

-    }

-

-    if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) {

-      break;

-    }

-

-    Indices[Level]  += 1;

-    Address          = (Level == 0) ? 0 : Addresses[Level - 1];

-    Addresses[Level] = Address | LShiftU64 (Indices[Level], Shifts[Level]);

-  }

-}

+/** @file
+  UEFI Heap Guard functions.
+
+Copyright (c) 2017-2018, Intel Corporation. All rights reserved.<BR>
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include "DxeMain.h"
+#include "Imem.h"
+#include "HeapGuard.h"
+
+//
+// Global to avoid infinite reentrance of memory allocation when updating
+// page table attributes, which may need allocate pages for new PDE/PTE.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED BOOLEAN  mOnGuarding = FALSE;
+
+//
+// Pointer to table tracking the Guarded memory with bitmap, in which  '1'
+// is used to indicate memory guarded. '0' might be free memory or Guard
+// page itself, depending on status of memory adjacent to it.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED UINT64  mGuardedMemoryMap = 0;
+
+//
+// Current depth level of map table pointed by mGuardedMemoryMap.
+// mMapLevel must be initialized at least by 1. It will be automatically
+// updated according to the address of memory just tracked.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED UINTN  mMapLevel = 1;
+
+//
+// Shift and mask for each level of map table
+//
+GLOBAL_REMOVE_IF_UNREFERENCED UINTN  mLevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH]
+  = GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS;
+GLOBAL_REMOVE_IF_UNREFERENCED UINTN  mLevelMask[GUARDED_HEAP_MAP_TABLE_DEPTH]
+  = GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS;
+
+//
+// Used for promoting freed but not used pages.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED EFI_PHYSICAL_ADDRESS  mLastPromotedPage = BASE_4GB;
+
+/**
+  Set corresponding bits in bitmap table to 1 according to the address.
+
+  @param[in]  Address     Start address to set for.
+  @param[in]  BitNumber   Number of bits to set.
+  @param[in]  BitMap      Pointer to bitmap which covers the Address.
+
+  @return VOID.
+**/
+STATIC
+VOID
+SetBits (
+  IN EFI_PHYSICAL_ADDRESS  Address,
+  IN UINTN                 BitNumber,
+  IN UINT64                *BitMap
+  )
+{
+  UINTN  Lsbs;
+  UINTN  Qwords;
+  UINTN  Msbs;
+  UINTN  StartBit;
+  UINTN  EndBit;
+
+  StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);
+  EndBit   = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+
+  if ((StartBit + BitNumber) >= GUARDED_HEAP_MAP_ENTRY_BITS) {
+    Msbs = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %
+           GUARDED_HEAP_MAP_ENTRY_BITS;
+    Lsbs   = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+    Qwords = (BitNumber - Msbs) / GUARDED_HEAP_MAP_ENTRY_BITS;
+  } else {
+    Msbs   = BitNumber;
+    Lsbs   = 0;
+    Qwords = 0;
+  }
+
+  if (Msbs > 0) {
+    *BitMap |= LShiftU64 (LShiftU64 (1, Msbs) - 1, StartBit);
+    BitMap  += 1;
+  }
+
+  if (Qwords > 0) {
+    SetMem64 (
+      (VOID *)BitMap,
+      Qwords * GUARDED_HEAP_MAP_ENTRY_BYTES,
+      (UINT64)-1
+      );
+    BitMap += Qwords;
+  }
+
+  if (Lsbs > 0) {
+    *BitMap |= (LShiftU64 (1, Lsbs) - 1);
+  }
+}
+
+/**
+  Set corresponding bits in bitmap table to 0 according to the address.
+
+  @param[in]  Address     Start address to set for.
+  @param[in]  BitNumber   Number of bits to set.
+  @param[in]  BitMap      Pointer to bitmap which covers the Address.
+
+  @return VOID.
+**/
+STATIC
+VOID
+ClearBits (
+  IN EFI_PHYSICAL_ADDRESS  Address,
+  IN UINTN                 BitNumber,
+  IN UINT64                *BitMap
+  )
+{
+  UINTN  Lsbs;
+  UINTN  Qwords;
+  UINTN  Msbs;
+  UINTN  StartBit;
+  UINTN  EndBit;
+
+  StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);
+  EndBit   = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+
+  if ((StartBit + BitNumber) >= GUARDED_HEAP_MAP_ENTRY_BITS) {
+    Msbs = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %
+           GUARDED_HEAP_MAP_ENTRY_BITS;
+    Lsbs   = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+    Qwords = (BitNumber - Msbs) / GUARDED_HEAP_MAP_ENTRY_BITS;
+  } else {
+    Msbs   = BitNumber;
+    Lsbs   = 0;
+    Qwords = 0;
+  }
+
+  if (Msbs > 0) {
+    *BitMap &= ~LShiftU64 (LShiftU64 (1, Msbs) - 1, StartBit);
+    BitMap  += 1;
+  }
+
+  if (Qwords > 0) {
+    SetMem64 ((VOID *)BitMap, Qwords * GUARDED_HEAP_MAP_ENTRY_BYTES, 0);
+    BitMap += Qwords;
+  }
+
+  if (Lsbs > 0) {
+    *BitMap &= ~(LShiftU64 (1, Lsbs) - 1);
+  }
+}
+
+/**
+  Get corresponding bits in bitmap table according to the address.
+
+  The value of bit 0 corresponds to the status of memory at given Address.
+  No more than 64 bits can be retrieved in one call.
+
+  @param[in]  Address     Start address to retrieve bits for.
+  @param[in]  BitNumber   Number of bits to get.
+  @param[in]  BitMap      Pointer to bitmap which covers the Address.
+
+  @return An integer containing the bits information.
+**/
+STATIC
+UINT64
+GetBits (
+  IN EFI_PHYSICAL_ADDRESS  Address,
+  IN UINTN                 BitNumber,
+  IN UINT64                *BitMap
+  )
+{
+  UINTN   StartBit;
+  UINTN   EndBit;
+  UINTN   Lsbs;
+  UINTN   Msbs;
+  UINT64  Result;
+
+  ASSERT (BitNumber <= GUARDED_HEAP_MAP_ENTRY_BITS);
+
+  StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);
+  EndBit   = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+
+  if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) {
+    Msbs = GUARDED_HEAP_MAP_ENTRY_BITS - StartBit;
+    Lsbs = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+  } else {
+    Msbs = BitNumber;
+    Lsbs = 0;
+  }
+
+  if ((StartBit == 0) && (BitNumber == GUARDED_HEAP_MAP_ENTRY_BITS)) {
+    Result = *BitMap;
+  } else {
+    Result = RShiftU64 ((*BitMap), StartBit) & (LShiftU64 (1, Msbs) - 1);
+    if (Lsbs > 0) {
+      BitMap += 1;
+      Result |= LShiftU64 ((*BitMap) & (LShiftU64 (1, Lsbs) - 1), Msbs);
+    }
+  }
+
+  return Result;
+}
+
+/**
+  Locate the pointer of bitmap from the guarded memory bitmap tables, which
+  covers the given Address.
+
+  @param[in]  Address       Start address to search the bitmap for.
+  @param[in]  AllocMapUnit  Flag to indicate memory allocation for the table.
+  @param[out] BitMap        Pointer to bitmap which covers the Address.
+
+  @return The bit number from given Address to the end of current map table.
+**/
+UINTN
+FindGuardedMemoryMap (
+  IN  EFI_PHYSICAL_ADDRESS  Address,
+  IN  BOOLEAN               AllocMapUnit,
+  OUT UINT64                **BitMap
+  )
+{
+  UINTN       Level;
+  UINT64      *GuardMap;
+  UINT64      MapMemory;
+  UINTN       Index;
+  UINTN       Size;
+  UINTN       BitsToUnitEnd;
+  EFI_STATUS  Status;
+
+  MapMemory = 0;
+
+  //
+  // Adjust current map table depth according to the address to access
+  //
+  while (AllocMapUnit &&
+         mMapLevel < GUARDED_HEAP_MAP_TABLE_DEPTH &&
+         RShiftU64 (
+           Address,
+           mLevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1]
+           ) != 0)
+  {
+    if (mGuardedMemoryMap != 0) {
+      Size = (mLevelMask[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1] + 1)
+             * GUARDED_HEAP_MAP_ENTRY_BYTES;
+      Status = CoreInternalAllocatePages (
+                 AllocateAnyPages,
+                 EfiBootServicesData,
+                 EFI_SIZE_TO_PAGES (Size),
+                 &MapMemory,
+                 FALSE
+                 );
+      ASSERT_EFI_ERROR (Status);
+      ASSERT (MapMemory != 0);
+
+      SetMem ((VOID *)(UINTN)MapMemory, Size, 0);
+
+      *(UINT64 *)(UINTN)MapMemory = mGuardedMemoryMap;
+      mGuardedMemoryMap           = MapMemory;
+    }
+
+    mMapLevel++;
+  }
+
+  GuardMap = &mGuardedMemoryMap;
+  for (Level = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+       Level < GUARDED_HEAP_MAP_TABLE_DEPTH;
+       ++Level)
+  {
+    if (*GuardMap == 0) {
+      if (!AllocMapUnit) {
+        GuardMap = NULL;
+        break;
+      }
+
+      Size   = (mLevelMask[Level] + 1) * GUARDED_HEAP_MAP_ENTRY_BYTES;
+      Status = CoreInternalAllocatePages (
+                 AllocateAnyPages,
+                 EfiBootServicesData,
+                 EFI_SIZE_TO_PAGES (Size),
+                 &MapMemory,
+                 FALSE
+                 );
+      ASSERT_EFI_ERROR (Status);
+      ASSERT (MapMemory != 0);
+
+      SetMem ((VOID *)(UINTN)MapMemory, Size, 0);
+      *GuardMap = MapMemory;
+    }
+
+    Index    = (UINTN)RShiftU64 (Address, mLevelShift[Level]);
+    Index   &= mLevelMask[Level];
+    GuardMap = (UINT64 *)(UINTN)((*GuardMap) + Index * sizeof (UINT64));
+  }
+
+  BitsToUnitEnd = GUARDED_HEAP_MAP_BITS - GUARDED_HEAP_MAP_BIT_INDEX (Address);
+  *BitMap       = GuardMap;
+
+  return BitsToUnitEnd;
+}
+
+/**
+  Set corresponding bits in bitmap table to 1 according to given memory range.
+
+  @param[in]  Address       Memory address to guard from.
+  @param[in]  NumberOfPages Number of pages to guard.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+SetGuardedMemoryBits (
+  IN EFI_PHYSICAL_ADDRESS  Address,
+  IN UINTN                 NumberOfPages
+  )
+{
+  UINT64  *BitMap;
+  UINTN   Bits;
+  UINTN   BitsToUnitEnd;
+
+  while (NumberOfPages > 0) {
+    BitsToUnitEnd = FindGuardedMemoryMap (Address, TRUE, &BitMap);
+    ASSERT (BitMap != NULL);
+
+    if (NumberOfPages > BitsToUnitEnd) {
+      // Cross map unit
+      Bits = BitsToUnitEnd;
+    } else {
+      Bits = NumberOfPages;
+    }
+
+    SetBits (Address, Bits, BitMap);
+
+    NumberOfPages -= Bits;
+    Address       += EFI_PAGES_TO_SIZE (Bits);
+  }
+}
+
+/**
+  Clear corresponding bits in bitmap table according to given memory range.
+
+  @param[in]  Address       Memory address to unset from.
+  @param[in]  NumberOfPages Number of pages to unset guard.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+ClearGuardedMemoryBits (
+  IN EFI_PHYSICAL_ADDRESS  Address,
+  IN UINTN                 NumberOfPages
+  )
+{
+  UINT64  *BitMap;
+  UINTN   Bits;
+  UINTN   BitsToUnitEnd;
+
+  while (NumberOfPages > 0) {
+    BitsToUnitEnd = FindGuardedMemoryMap (Address, TRUE, &BitMap);
+    ASSERT (BitMap != NULL);
+
+    if (NumberOfPages > BitsToUnitEnd) {
+      // Cross map unit
+      Bits = BitsToUnitEnd;
+    } else {
+      Bits = NumberOfPages;
+    }
+
+    ClearBits (Address, Bits, BitMap);
+
+    NumberOfPages -= Bits;
+    Address       += EFI_PAGES_TO_SIZE (Bits);
+  }
+}
+
+/**
+  Retrieve corresponding bits in bitmap table according to given memory range.
+
+  @param[in]  Address       Memory address to retrieve from.
+  @param[in]  NumberOfPages Number of pages to retrieve.
+
+  @return An integer containing the guarded memory bitmap.
+**/
+UINT64
+GetGuardedMemoryBits (
+  IN EFI_PHYSICAL_ADDRESS  Address,
+  IN UINTN                 NumberOfPages
+  )
+{
+  UINT64  *BitMap;
+  UINTN   Bits;
+  UINT64  Result;
+  UINTN   Shift;
+  UINTN   BitsToUnitEnd;
+
+  ASSERT (NumberOfPages <= GUARDED_HEAP_MAP_ENTRY_BITS);
+
+  Result = 0;
+  Shift  = 0;
+  while (NumberOfPages > 0) {
+    BitsToUnitEnd = FindGuardedMemoryMap (Address, FALSE, &BitMap);
+
+    if (NumberOfPages > BitsToUnitEnd) {
+      // Cross map unit
+      Bits = BitsToUnitEnd;
+    } else {
+      Bits = NumberOfPages;
+    }
+
+    if (BitMap != NULL) {
+      Result |= LShiftU64 (GetBits (Address, Bits, BitMap), Shift);
+    }
+
+    Shift         += Bits;
+    NumberOfPages -= Bits;
+    Address       += EFI_PAGES_TO_SIZE (Bits);
+  }
+
+  return Result;
+}
+
+/**
+  Get bit value in bitmap table for the given address.
+
+  @param[in]  Address     The address to retrieve for.
+
+  @return 1 or 0.
+**/
+UINTN
+EFIAPI
+GetGuardMapBit (
+  IN EFI_PHYSICAL_ADDRESS  Address
+  )
+{
+  UINT64  *GuardMap;
+
+  FindGuardedMemoryMap (Address, FALSE, &GuardMap);
+  if (GuardMap != NULL) {
+    if (RShiftU64 (
+          *GuardMap,
+          GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address)
+          ) & 1)
+    {
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+/**
+  Check to see if the page at the given address is a Guard page or not.
+
+  @param[in]  Address     The address to check for.
+
+  @return TRUE  The page at Address is a Guard page.
+  @return FALSE The page at Address is not a Guard page.
+**/
+BOOLEAN
+EFIAPI
+IsGuardPage (
+  IN EFI_PHYSICAL_ADDRESS  Address
+  )
+{
+  UINT64  BitMap;
+
+  //
+  // There must be at least one guarded page before and/or after given
+  // address if it's a Guard page. The bitmap pattern should be one of
+  // 001, 100 and 101
+  //
+  BitMap = GetGuardedMemoryBits (Address - EFI_PAGE_SIZE, 3);
+  return ((BitMap == BIT0) || (BitMap == BIT2) || (BitMap == (BIT2 | BIT0)));
+}
+
+/**
+  Check to see if the page at the given address is guarded or not.
+
+  @param[in]  Address     The address to check for.
+
+  @return TRUE  The page at Address is guarded.
+  @return FALSE The page at Address is not guarded.
+**/
+BOOLEAN
+EFIAPI
+IsMemoryGuarded (
+  IN EFI_PHYSICAL_ADDRESS  Address
+  )
+{
+  return (GetGuardMapBit (Address) == 1);
+}
+
+/**
+  Set the page at the given address to be a Guard page.
+
+  This is done by changing the page table attribute to be NOT PRSENT.
+
+  @param[in]  BaseAddress     Page address to Guard at
+
+  @return VOID
+**/
+VOID
+EFIAPI
+SetGuardPage (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress
+  )
+{
+  EFI_STATUS  Status;
+
+  if (gCpu == NULL) {
+    return;
+  }
+
+  //
+  // Set flag to make sure allocating memory without GUARD for page table
+  // operation; otherwise infinite loops could be caused.
+  //
+  mOnGuarding = TRUE;
+  //
+  // Note: This might overwrite other attributes needed by other features,
+  // such as NX memory protection.
+  //
+  Status = gCpu->SetMemoryAttributes (gCpu, BaseAddress, EFI_PAGE_SIZE, EFI_MEMORY_RP);
+  ASSERT_EFI_ERROR (Status);
+  mOnGuarding = FALSE;
+}
+
+/**
+  Unset the Guard page at the given address to the normal memory.
+
+  This is done by changing the page table attribute to be PRSENT.
+
+  @param[in]  BaseAddress     Page address to Guard at.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+UnsetGuardPage (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress
+  )
+{
+  UINT64      Attributes;
+  EFI_STATUS  Status;
+
+  if (gCpu == NULL) {
+    return;
+  }
+
+  //
+  // Once the Guard page is unset, it will be freed back to memory pool. NX
+  // memory protection must be restored for this page if NX is enabled for free
+  // memory.
+  //
+  Attributes = 0;
+  if ((PcdGet64 (PcdDxeNxMemoryProtectionPolicy) & (1 << EfiConventionalMemory)) != 0) {
+    Attributes |= EFI_MEMORY_XP;
+  }
+
+  //
+  // Set flag to make sure allocating memory without GUARD for page table
+  // operation; otherwise infinite loops could be caused.
+  //
+  mOnGuarding = TRUE;
+  //
+  // Note: This might overwrite other attributes needed by other features,
+  // such as memory protection (NX). Please make sure they are not enabled
+  // at the same time.
+  //
+  Status = gCpu->SetMemoryAttributes (gCpu, BaseAddress, EFI_PAGE_SIZE, Attributes);
+  ASSERT_EFI_ERROR (Status);
+  mOnGuarding = FALSE;
+}
+
+/**
+  Check to see if the memory at the given address should be guarded or not.
+
+  @param[in]  MemoryType      Memory type to check.
+  @param[in]  AllocateType    Allocation type to check.
+  @param[in]  PageOrPool      Indicate a page allocation or pool allocation.
+
+
+  @return TRUE  The given type of memory should be guarded.
+  @return FALSE The given type of memory should not be guarded.
+**/
+BOOLEAN
+IsMemoryTypeToGuard (
+  IN EFI_MEMORY_TYPE    MemoryType,
+  IN EFI_ALLOCATE_TYPE  AllocateType,
+  IN UINT8              PageOrPool
+  )
+{
+  UINT64  TestBit;
+  UINT64  ConfigBit;
+
+  if (AllocateType == AllocateAddress) {
+    return FALSE;
+  }
+
+  if ((PcdGet8 (PcdHeapGuardPropertyMask) & PageOrPool) == 0) {
+    return FALSE;
+  }
+
+  if (PageOrPool == GUARD_HEAP_TYPE_POOL) {
+    ConfigBit = PcdGet64 (PcdHeapGuardPoolType);
+  } else if (PageOrPool == GUARD_HEAP_TYPE_PAGE) {
+    ConfigBit = PcdGet64 (PcdHeapGuardPageType);
+  } else {
+    ConfigBit = (UINT64)-1;
+  }
+
+  if ((UINT32)MemoryType >= MEMORY_TYPE_OS_RESERVED_MIN) {
+    TestBit = BIT63;
+  } else if ((UINT32)MemoryType >= MEMORY_TYPE_OEM_RESERVED_MIN) {
+    TestBit = BIT62;
+  } else if (MemoryType < EfiMaxMemoryType) {
+    TestBit = LShiftU64 (1, MemoryType);
+  } else if (MemoryType == EfiMaxMemoryType) {
+    TestBit = (UINT64)-1;
+  } else {
+    TestBit = 0;
+  }
+
+  return ((ConfigBit & TestBit) != 0);
+}
+
+/**
+  Check to see if the pool at the given address should be guarded or not.
+
+  @param[in]  MemoryType      Pool type to check.
+
+
+  @return TRUE  The given type of pool should be guarded.
+  @return FALSE The given type of pool should not be guarded.
+**/
+BOOLEAN
+IsPoolTypeToGuard (
+  IN EFI_MEMORY_TYPE  MemoryType
+  )
+{
+  return IsMemoryTypeToGuard (
+           MemoryType,
+           AllocateAnyPages,
+           GUARD_HEAP_TYPE_POOL
+           );
+}
+
+/**
+  Check to see if the page at the given address should be guarded or not.
+
+  @param[in]  MemoryType      Page type to check.
+  @param[in]  AllocateType    Allocation type to check.
+
+  @return TRUE  The given type of page should be guarded.
+  @return FALSE The given type of page should not be guarded.
+**/
+BOOLEAN
+IsPageTypeToGuard (
+  IN EFI_MEMORY_TYPE    MemoryType,
+  IN EFI_ALLOCATE_TYPE  AllocateType
+  )
+{
+  return IsMemoryTypeToGuard (MemoryType, AllocateType, GUARD_HEAP_TYPE_PAGE);
+}
+
+/**
+  Check to see if the heap guard is enabled for page and/or pool allocation.
+
+  @param[in]  GuardType   Specify the sub-type(s) of Heap Guard.
+
+  @return TRUE/FALSE.
+**/
+BOOLEAN
+IsHeapGuardEnabled (
+  UINT8  GuardType
+  )
+{
+  return IsMemoryTypeToGuard (EfiMaxMemoryType, AllocateAnyPages, GuardType);
+}
+
+/**
+  Set head Guard and tail Guard for the given memory range.
+
+  @param[in]  Memory          Base address of memory to set guard for.
+  @param[in]  NumberOfPages   Memory size in pages.
+
+  @return VOID
+**/
+VOID
+SetGuardForMemory (
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NumberOfPages
+  )
+{
+  EFI_PHYSICAL_ADDRESS  GuardPage;
+
+  //
+  // Set tail Guard
+  //
+  GuardPage = Memory + EFI_PAGES_TO_SIZE (NumberOfPages);
+  if (!IsGuardPage (GuardPage)) {
+    SetGuardPage (GuardPage);
+  }
+
+  // Set head Guard
+  GuardPage = Memory - EFI_PAGES_TO_SIZE (1);
+  if (!IsGuardPage (GuardPage)) {
+    SetGuardPage (GuardPage);
+  }
+
+  //
+  // Mark the memory range as Guarded
+  //
+  SetGuardedMemoryBits (Memory, NumberOfPages);
+}
+
+/**
+  Unset head Guard and tail Guard for the given memory range.
+
+  @param[in]  Memory          Base address of memory to unset guard for.
+  @param[in]  NumberOfPages   Memory size in pages.
+
+  @return VOID
+**/
+VOID
+UnsetGuardForMemory (
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NumberOfPages
+  )
+{
+  EFI_PHYSICAL_ADDRESS  GuardPage;
+  UINT64                GuardBitmap;
+
+  if (NumberOfPages == 0) {
+    return;
+  }
+
+  //
+  // Head Guard must be one page before, if any.
+  //
+  //          MSB-> 1     0 <-LSB
+  //          -------------------
+  //  Head Guard -> 0     1 -> Don't free Head Guard  (shared Guard)
+  //  Head Guard -> 0     0 -> Free Head Guard either (not shared Guard)
+  //                1     X -> Don't free first page  (need a new Guard)
+  //                           (it'll be turned into a Guard page later)
+  //          -------------------
+  //      Start -> -1    -2
+  //
+  GuardPage   = Memory - EFI_PAGES_TO_SIZE (1);
+  GuardBitmap = GetGuardedMemoryBits (Memory - EFI_PAGES_TO_SIZE (2), 2);
+  if ((GuardBitmap & BIT1) == 0) {
+    //
+    // Head Guard exists.
+    //
+    if ((GuardBitmap & BIT0) == 0) {
+      //
+      // If the head Guard is not a tail Guard of adjacent memory block,
+      // unset it.
+      //
+      UnsetGuardPage (GuardPage);
+    }
+  } else {
+    //
+    // Pages before memory to free are still in Guard. It's a partial free
+    // case. Turn first page of memory block to free into a new Guard.
+    //
+    SetGuardPage (Memory);
+  }
+
+  //
+  // Tail Guard must be the page after this memory block to free, if any.
+  //
+  //   MSB-> 1     0 <-LSB
+  //  --------------------
+  //         1     0 <- Tail Guard -> Don't free Tail Guard  (shared Guard)
+  //         0     0 <- Tail Guard -> Free Tail Guard either (not shared Guard)
+  //         X     1               -> Don't free last page   (need a new Guard)
+  //                                 (it'll be turned into a Guard page later)
+  //  --------------------
+  //        +1    +0 <- End
+  //
+  GuardPage   = Memory + EFI_PAGES_TO_SIZE (NumberOfPages);
+  GuardBitmap = GetGuardedMemoryBits (GuardPage, 2);
+  if ((GuardBitmap & BIT0) == 0) {
+    //
+    // Tail Guard exists.
+    //
+    if ((GuardBitmap & BIT1) == 0) {
+      //
+      // If the tail Guard is not a head Guard of adjacent memory block,
+      // free it; otherwise, keep it.
+      //
+      UnsetGuardPage (GuardPage);
+    }
+  } else {
+    //
+    // Pages after memory to free are still in Guard. It's a partial free
+    // case. We need to keep one page to be a head Guard.
+    //
+    SetGuardPage (GuardPage - EFI_PAGES_TO_SIZE (1));
+  }
+
+  //
+  // No matter what, we just clear the mark of the Guarded memory.
+  //
+  ClearGuardedMemoryBits (Memory, NumberOfPages);
+}
+
+/**
+  Adjust address of free memory according to existing and/or required Guard.
+
+  This function will check if there're existing Guard pages of adjacent
+  memory blocks, and try to use it as the Guard page of the memory to be
+  allocated.
+
+  @param[in]  Start           Start address of free memory block.
+  @param[in]  Size            Size of free memory block.
+  @param[in]  SizeRequested   Size of memory to allocate.
+
+  @return The end address of memory block found.
+  @return 0 if no enough space for the required size of memory and its Guard.
+**/
+UINT64
+AdjustMemoryS (
+  IN UINT64  Start,
+  IN UINT64  Size,
+  IN UINT64  SizeRequested
+  )
+{
+  UINT64  Target;
+
+  //
+  // UEFI spec requires that allocated pool must be 8-byte aligned. If it's
+  // indicated to put the pool near the Tail Guard, we need extra bytes to
+  // make sure alignment of the returned pool address.
+  //
+  if ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) == 0) {
+    SizeRequested = ALIGN_VALUE (SizeRequested, 8);
+  }
+
+  Target = Start + Size - SizeRequested;
+  ASSERT (Target >= Start);
+  if (Target == 0) {
+    return 0;
+  }
+
+  if (!IsGuardPage (Start + Size)) {
+    // No Guard at tail to share. One more page is needed.
+    Target -= EFI_PAGES_TO_SIZE (1);
+  }
+
+  // Out of range?
+  if (Target < Start) {
+    return 0;
+  }
+
+  // At the edge?
+  if (Target == Start) {
+    if (!IsGuardPage (Target - EFI_PAGES_TO_SIZE (1))) {
+      // No enough space for a new head Guard if no Guard at head to share.
+      return 0;
+    }
+  }
+
+  // OK, we have enough pages for memory and its Guards. Return the End of the
+  // free space.
+  return Target + SizeRequested - 1;
+}
+
+/**
+  Adjust the start address and number of pages to free according to Guard.
+
+  The purpose of this function is to keep the shared Guard page with adjacent
+  memory block if it's still in guard, or free it if no more sharing. Another
+  is to reserve pages as Guard pages in partial page free situation.
+
+  @param[in,out]  Memory          Base address of memory to free.
+  @param[in,out]  NumberOfPages   Size of memory to free.
+
+  @return VOID.
+**/
+VOID
+AdjustMemoryF (
+  IN OUT EFI_PHYSICAL_ADDRESS  *Memory,
+  IN OUT UINTN                 *NumberOfPages
+  )
+{
+  EFI_PHYSICAL_ADDRESS  Start;
+  EFI_PHYSICAL_ADDRESS  MemoryToTest;
+  UINTN                 PagesToFree;
+  UINT64                GuardBitmap;
+
+  if ((Memory == NULL) || (NumberOfPages == NULL) || (*NumberOfPages == 0)) {
+    return;
+  }
+
+  Start       = *Memory;
+  PagesToFree = *NumberOfPages;
+
+  //
+  // Head Guard must be one page before, if any.
+  //
+  //          MSB-> 1     0 <-LSB
+  //          -------------------
+  //  Head Guard -> 0     1 -> Don't free Head Guard  (shared Guard)
+  //  Head Guard -> 0     0 -> Free Head Guard either (not shared Guard)
+  //                1     X -> Don't free first page  (need a new Guard)
+  //                           (it'll be turned into a Guard page later)
+  //          -------------------
+  //      Start -> -1    -2
+  //
+  MemoryToTest = Start - EFI_PAGES_TO_SIZE (2);
+  GuardBitmap  = GetGuardedMemoryBits (MemoryToTest, 2);
+  if ((GuardBitmap & BIT1) == 0) {
+    //
+    // Head Guard exists.
+    //
+    if ((GuardBitmap & BIT0) == 0) {
+      //
+      // If the head Guard is not a tail Guard of adjacent memory block,
+      // free it; otherwise, keep it.
+      //
+      Start       -= EFI_PAGES_TO_SIZE (1);
+      PagesToFree += 1;
+    }
+  } else {
+    //
+    // No Head Guard, and pages before memory to free are still in Guard. It's a
+    // partial free case. We need to keep one page to be a tail Guard.
+    //
+    Start       += EFI_PAGES_TO_SIZE (1);
+    PagesToFree -= 1;
+  }
+
+  //
+  // Tail Guard must be the page after this memory block to free, if any.
+  //
+  //   MSB-> 1     0 <-LSB
+  //  --------------------
+  //         1     0 <- Tail Guard -> Don't free Tail Guard  (shared Guard)
+  //         0     0 <- Tail Guard -> Free Tail Guard either (not shared Guard)
+  //         X     1               -> Don't free last page   (need a new Guard)
+  //                                 (it'll be turned into a Guard page later)
+  //  --------------------
+  //        +1    +0 <- End
+  //
+  MemoryToTest = Start + EFI_PAGES_TO_SIZE (PagesToFree);
+  GuardBitmap  = GetGuardedMemoryBits (MemoryToTest, 2);
+  if ((GuardBitmap & BIT0) == 0) {
+    //
+    // Tail Guard exists.
+    //
+    if ((GuardBitmap & BIT1) == 0) {
+      //
+      // If the tail Guard is not a head Guard of adjacent memory block,
+      // free it; otherwise, keep it.
+      //
+      PagesToFree += 1;
+    }
+  } else if (PagesToFree > 0) {
+    //
+    // No Tail Guard, and pages after memory to free are still in Guard. It's a
+    // partial free case. We need to keep one page to be a head Guard.
+    //
+    PagesToFree -= 1;
+  }
+
+  *Memory        = Start;
+  *NumberOfPages = PagesToFree;
+}
+
+/**
+  Adjust the base and number of pages to really allocate according to Guard.
+
+  @param[in,out]  Memory          Base address of free memory.
+  @param[in,out]  NumberOfPages   Size of memory to allocate.
+
+  @return VOID.
+**/
+VOID
+AdjustMemoryA (
+  IN OUT EFI_PHYSICAL_ADDRESS  *Memory,
+  IN OUT UINTN                 *NumberOfPages
+  )
+{
+  //
+  // FindFreePages() has already taken the Guard into account. It's safe to
+  // adjust the start address and/or number of pages here, to make sure that
+  // the Guards are also "allocated".
+  //
+  if (!IsGuardPage (*Memory + EFI_PAGES_TO_SIZE (*NumberOfPages))) {
+    // No tail Guard, add one.
+    *NumberOfPages += 1;
+  }
+
+  if (!IsGuardPage (*Memory - EFI_PAGE_SIZE)) {
+    // No head Guard, add one.
+    *Memory        -= EFI_PAGE_SIZE;
+    *NumberOfPages += 1;
+  }
+}
+
+/**
+  Adjust the pool head position to make sure the Guard page is adjavent to
+  pool tail or pool head.
+
+  @param[in]  Memory    Base address of memory allocated.
+  @param[in]  NoPages   Number of pages actually allocated.
+  @param[in]  Size      Size of memory requested.
+                        (plus pool head/tail overhead)
+
+  @return Address of pool head.
+**/
+VOID *
+AdjustPoolHeadA (
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NoPages,
+  IN UINTN                 Size
+  )
+{
+  if ((Memory == 0) || ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0)) {
+    //
+    // Pool head is put near the head Guard
+    //
+    return (VOID *)(UINTN)Memory;
+  }
+
+  //
+  // Pool head is put near the tail Guard
+  //
+  Size = ALIGN_VALUE (Size, 8);
+  return (VOID *)(UINTN)(Memory + EFI_PAGES_TO_SIZE (NoPages) - Size);
+}
+
+/**
+  Get the page base address according to pool head address.
+
+  @param[in]  Memory    Head address of pool to free.
+  @param[in]  NoPages   Number of pages actually allocated.
+  @param[in]  Size      Size of memory requested.
+                        (plus pool head/tail overhead)
+
+  @return Address of pool head.
+**/
+VOID *
+AdjustPoolHeadF (
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NoPages,
+  IN UINTN                 Size
+  )
+{
+  if ((Memory == 0) || ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0)) {
+    //
+    // Pool head is put near the head Guard
+    //
+    return (VOID *)(UINTN)Memory;
+  }
+
+  //
+  // Pool head is put near the tail Guard. We need to exactly undo the addition done in AdjustPoolHeadA
+  // because we may not have allocated the pool head on the first allocated page, since we are aligned to
+  // the tail and on some architectures, the runtime page allocation granularity is > one page. So we allocate
+  // more pages than we need and put the pool head somewhere past the first page.
+  //
+  return (VOID *)(UINTN)(Memory + Size - EFI_PAGES_TO_SIZE (NoPages));
+}
+
+/**
+  Allocate or free guarded memory.
+
+  @param[in]  Start           Start address of memory to allocate or free.
+  @param[in]  NumberOfPages   Memory size in pages.
+  @param[in]  NewType         Memory type to convert to.
+
+  @return VOID.
+**/
+EFI_STATUS
+CoreConvertPagesWithGuard (
+  IN UINT64           Start,
+  IN UINTN            NumberOfPages,
+  IN EFI_MEMORY_TYPE  NewType
+  )
+{
+  UINT64  OldStart;
+  UINTN   OldPages;
+
+  if (NewType == EfiConventionalMemory) {
+    OldStart = Start;
+    OldPages = NumberOfPages;
+
+    AdjustMemoryF (&Start, &NumberOfPages);
+    //
+    // It's safe to unset Guard page inside memory lock because there should
+    // be no memory allocation occurred in updating memory page attribute at
+    // this point. And unsetting Guard page before free will prevent Guard
+    // page just freed back to pool from being allocated right away before
+    // marking it usable (from non-present to present).
+    //
+    UnsetGuardForMemory (OldStart, OldPages);
+    if (NumberOfPages == 0) {
+      return EFI_SUCCESS;
+    }
+  } else {
+    AdjustMemoryA (&Start, &NumberOfPages);
+  }
+
+  return CoreConvertPages (Start, NumberOfPages, NewType);
+}
+
+/**
+  Set all Guard pages which cannot be set before CPU Arch Protocol installed.
+**/
+VOID
+SetAllGuardPages (
+  VOID
+  )
+{
+  UINTN    Entries[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN    Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN    Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64   Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64   Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64   TableEntry;
+  UINT64   Address;
+  UINT64   GuardPage;
+  INTN     Level;
+  UINTN    Index;
+  BOOLEAN  OnGuarding;
+
+  if ((mGuardedMemoryMap == 0) ||
+      (mMapLevel == 0) ||
+      (mMapLevel > GUARDED_HEAP_MAP_TABLE_DEPTH))
+  {
+    return;
+  }
+
+  CopyMem (Entries, mLevelMask, sizeof (Entries));
+  CopyMem (Shifts, mLevelShift, sizeof (Shifts));
+
+  SetMem (Tables, sizeof (Tables), 0);
+  SetMem (Addresses, sizeof (Addresses), 0);
+  SetMem (Indices, sizeof (Indices), 0);
+
+  Level         = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+  Tables[Level] = mGuardedMemoryMap;
+  Address       = 0;
+  OnGuarding    = FALSE;
+
+  DEBUG_CODE (
+    DumpGuardedMemoryBitmap ();
+    );
+
+  while (TRUE) {
+    if (Indices[Level] > Entries[Level]) {
+      Tables[Level] = 0;
+      Level        -= 1;
+    } else {
+      TableEntry = ((UINT64 *)(UINTN)(Tables[Level]))[Indices[Level]];
+      Address    = Addresses[Level];
+
+      if (TableEntry == 0) {
+        OnGuarding = FALSE;
+      } else if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {
+        Level           += 1;
+        Tables[Level]    = TableEntry;
+        Addresses[Level] = Address;
+        Indices[Level]   = 0;
+
+        continue;
+      } else {
+        Index = 0;
+        while (Index < GUARDED_HEAP_MAP_ENTRY_BITS) {
+          if ((TableEntry & 1) == 1) {
+            if (OnGuarding) {
+              GuardPage = 0;
+            } else {
+              GuardPage = Address - EFI_PAGE_SIZE;
+            }
+
+            OnGuarding = TRUE;
+          } else {
+            if (OnGuarding) {
+              GuardPage = Address;
+            } else {
+              GuardPage = 0;
+            }
+
+            OnGuarding = FALSE;
+          }
+
+          if (GuardPage != 0) {
+            SetGuardPage (GuardPage);
+          }
+
+          if (TableEntry == 0) {
+            break;
+          }
+
+          TableEntry = RShiftU64 (TableEntry, 1);
+          Address   += EFI_PAGE_SIZE;
+          Index     += 1;
+        }
+      }
+    }
+
+    if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) {
+      break;
+    }
+
+    Indices[Level]  += 1;
+    Address          = (Level == 0) ? 0 : Addresses[Level - 1];
+    Addresses[Level] = Address | LShiftU64 (Indices[Level], Shifts[Level]);
+  }
+}
+
+/**
+  Find the address of top-most guarded free page.
+
+  @param[out]  Address    Start address of top-most guarded free page.
+
+  @return VOID.
+**/
+VOID
+GetLastGuardedFreePageAddress (
+  OUT EFI_PHYSICAL_ADDRESS  *Address
+  )
+{
+  EFI_PHYSICAL_ADDRESS  AddressGranularity;
+  EFI_PHYSICAL_ADDRESS  BaseAddress;
+  UINTN                 Level;
+  UINT64                Map;
+  INTN                  Index;
+
+  ASSERT (mMapLevel >= 1);
+
+  BaseAddress = 0;
+  Map         = mGuardedMemoryMap;
+  for (Level = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+       Level < GUARDED_HEAP_MAP_TABLE_DEPTH;
+       ++Level)
+  {
+    AddressGranularity = LShiftU64 (1, mLevelShift[Level]);
+
+    //
+    // Find the non-NULL entry at largest index.
+    //
+    for (Index = (INTN)mLevelMask[Level]; Index >= 0; --Index) {
+      if (((UINT64 *)(UINTN)Map)[Index] != 0) {
+        BaseAddress += MultU64x32 (AddressGranularity, (UINT32)Index);
+        Map          = ((UINT64 *)(UINTN)Map)[Index];
+        break;
+      }
+    }
+  }
+
+  //
+  // Find the non-zero MSB then get the page address.
+  //
+  while (Map != 0) {
+    Map          = RShiftU64 (Map, 1);
+    BaseAddress += EFI_PAGES_TO_SIZE (1);
+  }
+
+  *Address = BaseAddress;
+}
+
+/**
+  Record freed pages.
+
+  @param[in]  BaseAddress   Base address of just freed pages.
+  @param[in]  Pages         Number of freed pages.
+
+  @return VOID.
+**/
+VOID
+MarkFreedPages (
+  IN EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN UINTN                 Pages
+  )
+{
+  SetGuardedMemoryBits (BaseAddress, Pages);
+}
+
+/**
+  Record freed pages as well as mark them as not-present.
+
+  @param[in]  BaseAddress   Base address of just freed pages.
+  @param[in]  Pages         Number of freed pages.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+GuardFreedPages (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN  UINTN                 Pages
+  )
+{
+  EFI_STATUS  Status;
+
+  //
+  // Legacy memory lower than 1MB might be accessed with no allocation. Leave
+  // them alone.
+  //
+  if (BaseAddress < BASE_1MB) {
+    return;
+  }
+
+  MarkFreedPages (BaseAddress, Pages);
+  if (gCpu != NULL) {
+    //
+    // Set flag to make sure allocating memory without GUARD for page table
+    // operation; otherwise infinite loops could be caused.
+    //
+    mOnGuarding = TRUE;
+    //
+    // Note: This might overwrite other attributes needed by other features,
+    // such as NX memory protection.
+    //
+    Status = gCpu->SetMemoryAttributes (
+                     gCpu,
+                     BaseAddress,
+                     EFI_PAGES_TO_SIZE (Pages),
+                     EFI_MEMORY_RP
+                     );
+    //
+    // Normally we should ASSERT the returned Status. But there might be memory
+    // alloc/free involved in SetMemoryAttributes(), which might fail this
+    // calling. It's rare case so it's OK to let a few tiny holes be not-guarded.
+    //
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_WARN, "Failed to guard freed pages: %p (%lu)\n", BaseAddress, (UINT64)Pages));
+    }
+
+    mOnGuarding = FALSE;
+  }
+}
+
+/**
+  Record freed pages as well as mark them as not-present, if enabled.
+
+  @param[in]  BaseAddress   Base address of just freed pages.
+  @param[in]  Pages         Number of freed pages.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+GuardFreedPagesChecked (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN  UINTN                 Pages
+  )
+{
+  if (IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED)) {
+    GuardFreedPages (BaseAddress, Pages);
+  }
+}
+
+/**
+  Mark all pages freed before CPU Arch Protocol as not-present.
+
+**/
+VOID
+GuardAllFreedPages (
+  VOID
+  )
+{
+  UINTN   Entries[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN   Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN   Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64  Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64  Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64  TableEntry;
+  UINT64  Address;
+  UINT64  GuardPage;
+  INTN    Level;
+  UINT64  BitIndex;
+  UINTN   GuardPageNumber;
+
+  if ((mGuardedMemoryMap == 0) ||
+      (mMapLevel == 0) ||
+      (mMapLevel > GUARDED_HEAP_MAP_TABLE_DEPTH))
+  {
+    return;
+  }
+
+  CopyMem (Entries, mLevelMask, sizeof (Entries));
+  CopyMem (Shifts, mLevelShift, sizeof (Shifts));
+
+  SetMem (Tables, sizeof (Tables), 0);
+  SetMem (Addresses, sizeof (Addresses), 0);
+  SetMem (Indices, sizeof (Indices), 0);
+
+  Level           = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+  Tables[Level]   = mGuardedMemoryMap;
+  Address         = 0;
+  GuardPage       = (UINT64)-1;
+  GuardPageNumber = 0;
+
+  while (TRUE) {
+    if (Indices[Level] > Entries[Level]) {
+      Tables[Level] = 0;
+      Level        -= 1;
+    } else {
+      TableEntry = ((UINT64 *)(UINTN)(Tables[Level]))[Indices[Level]];
+      Address    = Addresses[Level];
+
+      if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {
+        Level           += 1;
+        Tables[Level]    = TableEntry;
+        Addresses[Level] = Address;
+        Indices[Level]   = 0;
+
+        continue;
+      } else {
+        BitIndex = 1;
+        while (BitIndex != 0) {
+          if ((TableEntry & BitIndex) != 0) {
+            if (GuardPage == (UINT64)-1) {
+              GuardPage = Address;
+            }
+
+            ++GuardPageNumber;
+          } else if (GuardPageNumber > 0) {
+            GuardFreedPages (GuardPage, GuardPageNumber);
+            GuardPageNumber = 0;
+            GuardPage       = (UINT64)-1;
+          }
+
+          if (TableEntry == 0) {
+            break;
+          }
+
+          Address += EFI_PAGES_TO_SIZE (1);
+          BitIndex = LShiftU64 (BitIndex, 1);
+        }
+      }
+    }
+
+    if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) {
+      break;
+    }
+
+    Indices[Level]  += 1;
+    Address          = (Level == 0) ? 0 : Addresses[Level - 1];
+    Addresses[Level] = Address | LShiftU64 (Indices[Level], Shifts[Level]);
+  }
+
+  //
+  // Update the maximum address of freed page which can be used for memory
+  // promotion upon out-of-memory-space.
+  //
+  GetLastGuardedFreePageAddress (&Address);
+  if (Address != 0) {
+    mLastPromotedPage = Address;
+  }
+}
+
+/**
+  This function checks to see if the given memory map descriptor in a memory map
+  can be merged with any guarded free pages.
+
+  @param  MemoryMapEntry    A pointer to a descriptor in MemoryMap.
+  @param  MaxAddress        Maximum address to stop the merge.
+
+  @return VOID
+
+**/
+VOID
+MergeGuardPages (
+  IN EFI_MEMORY_DESCRIPTOR  *MemoryMapEntry,
+  IN EFI_PHYSICAL_ADDRESS   MaxAddress
+  )
+{
+  EFI_PHYSICAL_ADDRESS  EndAddress;
+  UINT64                Bitmap;
+  INTN                  Pages;
+
+  if (!IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED) ||
+      (MemoryMapEntry->Type >= EfiMemoryMappedIO))
+  {
+    return;
+  }
+
+  Bitmap = 0;
+  Pages  = EFI_SIZE_TO_PAGES ((UINTN)(MaxAddress - MemoryMapEntry->PhysicalStart));
+  Pages -= (INTN)MemoryMapEntry->NumberOfPages;
+  while (Pages > 0) {
+    if (Bitmap == 0) {
+      EndAddress = MemoryMapEntry->PhysicalStart +
+                   EFI_PAGES_TO_SIZE ((UINTN)MemoryMapEntry->NumberOfPages);
+      Bitmap = GetGuardedMemoryBits (EndAddress, GUARDED_HEAP_MAP_ENTRY_BITS);
+    }
+
+    if ((Bitmap & 1) == 0) {
+      break;
+    }
+
+    Pages--;
+    MemoryMapEntry->NumberOfPages++;
+    Bitmap = RShiftU64 (Bitmap, 1);
+  }
+}
+
+/**
+  Put part (at most 64 pages a time) guarded free pages back to free page pool.
+
+  Freed memory guard is used to detect Use-After-Free (UAF) memory issue, which
+  makes use of 'Used then throw away' way to detect any illegal access to freed
+  memory. The thrown-away memory will be marked as not-present so that any access
+  to those memory (after free) will be caught by page-fault exception.
+
+  The problem is that this will consume lots of memory space. Once no memory
+  left in pool to allocate, we have to restore part of the freed pages to their
+  normal function. Otherwise the whole system will stop functioning.
+
+  @param  StartAddress    Start address of promoted memory.
+  @param  EndAddress      End address of promoted memory.
+
+  @return TRUE    Succeeded to promote memory.
+  @return FALSE   No free memory found.
+
+**/
+BOOLEAN
+PromoteGuardedFreePages (
+  OUT EFI_PHYSICAL_ADDRESS  *StartAddress,
+  OUT EFI_PHYSICAL_ADDRESS  *EndAddress
+  )
+{
+  EFI_STATUS            Status;
+  UINTN                 AvailablePages;
+  UINT64                Bitmap;
+  EFI_PHYSICAL_ADDRESS  Start;
+
+  if (!IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED)) {
+    return FALSE;
+  }
+
+  //
+  // Similar to memory allocation service, always search the freed pages in
+  // descending direction.
+  //
+  Start          = mLastPromotedPage;
+  AvailablePages = 0;
+  while (AvailablePages == 0) {
+    Start -= EFI_PAGES_TO_SIZE (GUARDED_HEAP_MAP_ENTRY_BITS);
+    //
+    // If the address wraps around, try the really freed pages at top.
+    //
+    if (Start > mLastPromotedPage) {
+      GetLastGuardedFreePageAddress (&Start);
+      ASSERT (Start != 0);
+      Start -= EFI_PAGES_TO_SIZE (GUARDED_HEAP_MAP_ENTRY_BITS);
+    }
+
+    Bitmap = GetGuardedMemoryBits (Start, GUARDED_HEAP_MAP_ENTRY_BITS);
+    while (Bitmap > 0) {
+      if ((Bitmap & 1) != 0) {
+        ++AvailablePages;
+      } else if (AvailablePages == 0) {
+        Start += EFI_PAGES_TO_SIZE (1);
+      } else {
+        break;
+      }
+
+      Bitmap = RShiftU64 (Bitmap, 1);
+    }
+  }
+
+  if (AvailablePages != 0) {
+    DEBUG ((DEBUG_INFO, "Promoted pages: %lX (%lx)\r\n", Start, (UINT64)AvailablePages));
+    ClearGuardedMemoryBits (Start, AvailablePages);
+
+    if (gCpu != NULL) {
+      //
+      // Set flag to make sure allocating memory without GUARD for page table
+      // operation; otherwise infinite loops could be caused.
+      //
+      mOnGuarding = TRUE;
+      Status      = gCpu->SetMemoryAttributes (gCpu, Start, EFI_PAGES_TO_SIZE (AvailablePages), 0);
+      ASSERT_EFI_ERROR (Status);
+      mOnGuarding = FALSE;
+    }
+
+    mLastPromotedPage = Start;
+    *StartAddress     = Start;
+    *EndAddress       = Start + EFI_PAGES_TO_SIZE (AvailablePages) - 1;
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+/**
+  Notify function used to set all Guard pages before CPU Arch Protocol installed.
+**/
+VOID
+HeapGuardCpuArchProtocolNotify (
+  VOID
+  )
+{
+  ASSERT (gCpu != NULL);
+
+  if (IsHeapGuardEnabled (GUARD_HEAP_TYPE_PAGE|GUARD_HEAP_TYPE_POOL) &&
+      IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED))
+  {
+    DEBUG ((DEBUG_ERROR, "Heap guard and freed memory guard cannot be enabled at the same time.\n"));
+    CpuDeadLoop ();
+  }
+
+  if (IsHeapGuardEnabled (GUARD_HEAP_TYPE_PAGE|GUARD_HEAP_TYPE_POOL)) {
+    SetAllGuardPages ();
+  }
+
+  if (IsHeapGuardEnabled (GUARD_HEAP_TYPE_FREED)) {
+    GuardAllFreedPages ();
+  }
+}
+
+/**
+  Helper function to convert a UINT64 value in binary to a string.
+
+  @param[in]  Value       Value of a UINT64 integer.
+  @param[out]  BinString   String buffer to contain the conversion result.
+
+  @return VOID.
+**/
+VOID
+Uint64ToBinString (
+  IN  UINT64  Value,
+  OUT CHAR8   *BinString
+  )
+{
+  UINTN  Index;
+
+  if (BinString == NULL) {
+    return;
+  }
+
+  for (Index = 64; Index > 0; --Index) {
+    BinString[Index - 1] = '0' + (Value & 1);
+    Value                = RShiftU64 (Value, 1);
+  }
+
+  BinString[64] = '\0';
+}
+
+/**
+  Dump the guarded memory bit map.
+**/
+VOID
+EFIAPI
+DumpGuardedMemoryBitmap (
+  VOID
+  )
+{
+  UINTN   Entries[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN   Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN   Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64  Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64  Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64  TableEntry;
+  UINT64  Address;
+  INTN    Level;
+  UINTN   RepeatZero;
+  CHAR8   String[GUARDED_HEAP_MAP_ENTRY_BITS + 1];
+  CHAR8   *Ruler1;
+  CHAR8   *Ruler2;
+
+  if (!IsHeapGuardEnabled (GUARD_HEAP_TYPE_ALL)) {
+    return;
+  }
+
+  if ((mGuardedMemoryMap == 0) ||
+      (mMapLevel == 0) ||
+      (mMapLevel > GUARDED_HEAP_MAP_TABLE_DEPTH))
+  {
+    return;
+  }
+
+  Ruler1 = "               3               2               1               0";
+  Ruler2 = "FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210";
+
+  DEBUG ((
+    HEAP_GUARD_DEBUG_LEVEL,
+    "============================="
+    " Guarded Memory Bitmap "
+    "==============================\r\n"
+    ));
+  DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "                  %a\r\n", Ruler1));
+  DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "                  %a\r\n", Ruler2));
+
+  CopyMem (Entries, mLevelMask, sizeof (Entries));
+  CopyMem (Shifts, mLevelShift, sizeof (Shifts));
+
+  SetMem (Indices, sizeof (Indices), 0);
+  SetMem (Tables, sizeof (Tables), 0);
+  SetMem (Addresses, sizeof (Addresses), 0);
+
+  Level         = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+  Tables[Level] = mGuardedMemoryMap;
+  Address       = 0;
+  RepeatZero    = 0;
+
+  while (TRUE) {
+    if (Indices[Level] > Entries[Level]) {
+      Tables[Level] = 0;
+      Level        -= 1;
+      RepeatZero    = 0;
+
+      DEBUG ((
+        HEAP_GUARD_DEBUG_LEVEL,
+        "========================================="
+        "=========================================\r\n"
+        ));
+    } else {
+      TableEntry = ((UINT64 *)(UINTN)Tables[Level])[Indices[Level]];
+      Address    = Addresses[Level];
+
+      if (TableEntry == 0) {
+        if (Level == GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {
+          if (RepeatZero == 0) {
+            Uint64ToBinString (TableEntry, String);
+            DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "%016lx: %a\r\n", Address, String));
+          } else if (RepeatZero == 1) {
+            DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "...             : ...\r\n"));
+          }
+
+          RepeatZero += 1;
+        }
+      } else if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {
+        Level           += 1;
+        Tables[Level]    = TableEntry;
+        Addresses[Level] = Address;
+        Indices[Level]   = 0;
+        RepeatZero       = 0;
+
+        continue;
+      } else {
+        RepeatZero = 0;
+        Uint64ToBinString (TableEntry, String);
+        DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "%016lx: %a\r\n", Address, String));
+      }
+    }
+
+    if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) {
+      break;
+    }
+
+    Indices[Level]  += 1;
+    Address          = (Level == 0) ? 0 : Addresses[Level - 1];
+    Addresses[Level] = Address | LShiftU64 (Indices[Level], Shifts[Level]);
+  }
+}