[edk2] [PATCH 1/5] MdeModulePkg/DxeCore: Implement heap guard feature for UEFI

Jian J Wang posted 5 patches 7 years, 2 months ago
There is a newer version of this series
[edk2] [PATCH 1/5] MdeModulePkg/DxeCore: Implement heap guard feature for UEFI
Posted by Jian J Wang 7 years, 2 months ago
This feature makes use of paging mechanism to add a hidden (not present)
page just before and after the allocated memory block. If the code tries
to access memory outside of the allocated part, page fault exception will
be triggered.

This feature is controlled by three PCDs:

    gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask
    gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPoolType
    gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPageType

BIT0 and BIT1 of PcdHeapGuardPropertyMask can be used to enable or disable
memory guard for page and pool respectively. PcdHeapGuardPoolType and/or
PcdHeapGuardPageType are used to enable or disable guard for specific type
of memory. For example, we can turn on guard only for EfiBootServicesData
and EfiRuntimeServicesData by setting the PCD with value 0x50.

Pool memory is not ususally integer multiple of one page, and is more likely
less than a page. There's no way to monitor the overflow at both top and
bottom of pool memory. BIT7 of PcdHeapGuardPropertyMask is used to control
how to position the head of pool memory so that it's easier to catch memory
overflow in memory growing direction or in decreasing direction.

Note: Turning on heap guard, especially pool guard, will introduce too many
memory fragments. Windows 10 has a limitation in its boot loader, which
accepts at most 512 memory descriptors passed from BIOS. This will prevent
Windows 10 from booting if heap guard is enabled. The latest Linux
distribution with grub boot loader has no such issue. Normally it's not
recommended to enable this feature in production build of BIOS.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Ayellet Wolman <ayellet.wolman@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
 MdeModulePkg/Core/Dxe/DxeMain.inf     |    4 +
 MdeModulePkg/Core/Dxe/Mem/HeapGuard.c | 1171 +++++++++++++++++++++++++++++++++
 MdeModulePkg/Core/Dxe/Mem/HeapGuard.h |  391 +++++++++++
 MdeModulePkg/Core/Dxe/Mem/Imem.h      |   38 +-
 MdeModulePkg/Core/Dxe/Mem/Page.c      |  129 +++-
 MdeModulePkg/Core/Dxe/Mem/Pool.c      |  154 ++++-
 6 files changed, 1823 insertions(+), 64 deletions(-)
 create mode 100644 MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
 create mode 100644 MdeModulePkg/Core/Dxe/Mem/HeapGuard.h

diff --git a/MdeModulePkg/Core/Dxe/DxeMain.inf b/MdeModulePkg/Core/Dxe/DxeMain.inf
index e29d6c83ae..6b27714a79 100644
--- a/MdeModulePkg/Core/Dxe/DxeMain.inf
+++ b/MdeModulePkg/Core/Dxe/DxeMain.inf
@@ -56,6 +56,7 @@
   Mem/MemData.c
   Mem/Imem.h
   Mem/MemoryProfileRecord.c
+  Mem/HeapGuard.c
   FwVolBlock/FwVolBlock.c
   FwVolBlock/FwVolBlock.h
   FwVol/FwVolWrite.c
@@ -192,6 +193,9 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable                   ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy                   ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy             ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPageType                       ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPoolType                       ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask                   ## CONSUMES
 
 # [Hob]
 # RESOURCE_DESCRIPTOR   ## CONSUMES
diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
new file mode 100644
index 0000000000..36e41d9a87
--- /dev/null
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
@@ -0,0 +1,1171 @@
+/** @file
+  UEFI Heap Guard functions.
+
+Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#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 = NULL;
+
+//
+// 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;
+
+/**
+  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;
+  }
+
+  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;
+  UINTN                   LevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH]
+                            = GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS;
+  UINTN                   LevelMask[GUARDED_HEAP_MAP_TABLE_DEPTH]
+                            = GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS;
+  UINT64                  **GuardMap;
+  UINT64                  *MapMemory;
+  UINTN                   Index;
+  UINTN                   Size;
+  UINTN                   BitsToUnitEnd;
+  EFI_STATUS              Status;
+
+  //
+  // Adjust current map table depth according to the address to access
+  //
+  while (mMapLevel < GUARDED_HEAP_MAP_TABLE_DEPTH
+         &&
+         RShiftU64 (
+           Address,
+           LevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1]
+           ) != 0) {
+
+    if (mGuardedMemoryMap != NULL) {
+      Size = (LevelMask[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1] + 1)
+             * GUARDED_HEAP_MAP_ENTRY_BYTES;
+      Status = CoreInternalAllocatePages (
+                  AllocateAnyPages,
+                  EfiBootServicesData,
+                  EFI_SIZE_TO_PAGES (Size),
+                  (EFI_PHYSICAL_ADDRESS *)&MapMemory,
+                  FALSE
+                  );
+      ASSERT_EFI_ERROR (Status);
+      ASSERT (MapMemory != NULL);
+
+      SetMem ((VOID *)MapMemory, Size, 0);
+
+      *(UINT64 **)MapMemory = mGuardedMemoryMap;
+      mGuardedMemoryMap     = MapMemory;
+    }
+
+    mMapLevel++;
+
+  }
+
+  GuardMap = &mGuardedMemoryMap;
+  for (Level = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+       Level < GUARDED_HEAP_MAP_TABLE_DEPTH;
+       ++Level) {
+
+    if (*GuardMap == NULL) {
+      if (!AllocMapUnit) {
+        GuardMap = NULL;
+        break;
+      }
+
+      Size = (LevelMask[Level] + 1) * GUARDED_HEAP_MAP_ENTRY_BYTES;
+      Status = CoreInternalAllocatePages (
+                  AllocateAnyPages,
+                  EfiBootServicesData,
+                  EFI_SIZE_TO_PAGES (Size),
+                  (EFI_PHYSICAL_ADDRESS *)&MapMemory,
+                  FALSE
+                  );
+      ASSERT_EFI_ERROR (Status);
+      ASSERT (MapMemory != NULL);
+
+      SetMem ((VOID *)MapMemory, Size, 0);
+      *GuardMap = (UINT64 *)MapMemory;
+    }
+
+    Index     = (UINTN)RShiftU64 (Address, LevelShift[Level]);
+    Index     &= LevelMask[Level];
+    GuardMap  = (UINT64 **)((*GuardMap) + Index);
+
+  }
+
+  BitsToUnitEnd = GUARDED_HEAP_MAP_BITS - GUARDED_HEAP_MAP_BIT_INDEX (Address);
+  *BitMap       = (UINT64 *)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 VOID
+**/
+UINTN
+GetGuardedMemoryBits (
+  IN EFI_PHYSICAL_ADDRESS    Address,
+  IN UINTN                   NumberOfPages
+  )
+{
+  UINT64            *BitMap;
+  UINTN             Bits;
+  UINTN             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;
+}
+
+/**
+  Set the bit in bitmap table for the given address
+
+  @param[in]  Address     The address to set for
+
+  @return VOID
+**/
+VOID
+EFIAPI
+SetGuardMapBit (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  UINT64        *GuardMap;
+  UINT64        BitMask;
+
+  FindGuardedMemoryMap (Address, TRUE, &GuardMap);
+  if (GuardMap != NULL) {
+    BitMask = LShiftU64 (1, GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address));
+    *GuardMap |= BitMask;
+  }
+}
+
+/**
+  Clear the bit in bitmap table for the given address
+
+  @param[in]  Address     The address to clear for
+
+  @return VOID
+**/
+VOID
+EFIAPI
+ClearGuardMapBit (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  UINT64        *GuardMap;
+  UINTN         BitMask;
+
+  FindGuardedMemoryMap (Address, TRUE, &GuardMap);
+  if (GuardMap != NULL) {
+    BitMask = LShiftU64 (1, GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address));
+    *GuardMap &= ~BitMask;
+  }
+}
+
+/**
+  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
+  )
+{
+  UINTN       BitMap;
+
+  BitMap = GetGuardedMemoryBits (Address - EFI_PAGE_SIZE, 3);
+  return (BitMap == 0b001 || BitMap == 0b100 || BitMap == 0b101);
+}
+
+/**
+  Check to see if the page at the given address is a head Guard page or not
+
+  @param[in]  Address     The address to check for
+
+  @return TRUE  The page at Address is a head Guard page
+  @return FALSE The page at Address is not a head Guard page
+**/
+BOOLEAN
+EFIAPI
+IsHeadGuard (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  return (GetGuardedMemoryBits (Address, 2) == 0b10);
+}
+
+/**
+  Check to see if the page at the given address is a tail Guard page or not
+
+  @param[in]  Address     The address to check for
+
+  @return TRUE  The page at Address is a tail Guard page
+  @return FALSE The page at Address is not a tail Guard page
+**/
+BOOLEAN
+EFIAPI
+IsTailGuard (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  return (GetGuardedMemoryBits (Address - EFI_PAGE_SIZE, 2) == 0b01);
+}
+
+/**
+  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]  Address     Page address to Guard at
+
+  @return VOID
+**/
+VOID
+EFIAPI
+SetGuardPage (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress
+  )
+{
+  mOnGuarding = TRUE;
+  gCpu->SetMemoryAttributes (gCpu, BaseAddress, EFI_PAGE_SIZE, EFI_MEMORY_RP);
+  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]  Address     Page address to Guard at
+
+  @return VOID
+**/
+VOID
+EFIAPI
+UnsetGuardPage (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress
+  )
+{
+  mOnGuarding = TRUE;
+  gCpu->SetMemoryAttributes (gCpu, BaseAddress, EFI_PAGE_SIZE, 0);
+  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;
+  BOOLEAN     InSmm;
+
+  if (gCpu == NULL || AllocateType == AllocateAddress) {
+    return FALSE;
+  }
+
+  InSmm = FALSE;
+  if (gSmmBase2 != NULL) {
+    gSmmBase2->InSmm (gSmmBase2, &InSmm);
+  }
+
+  if (InSmm) {
+    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);
+}
+
+/**
+  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;
+
+  if (NumberOfPages == 0) {
+    return;
+  }
+
+  //
+  // Head Guard must be one page before, if any.
+  //
+  GuardPage = Memory - EFI_PAGES_TO_SIZE (1);
+  if (IsHeadGuard (GuardPage)) {
+    if (!IsMemoryGuarded (GuardPage - EFI_PAGES_TO_SIZE (1))) {
+      //
+      // If the head Guard is not a tail Guard of adjacent memory block,
+      // unset it.
+      //
+      UnsetGuardPage (GuardPage);
+    }
+  } else if (IsMemoryGuarded (GuardPage)) {
+    //
+    // 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.
+  //
+  GuardPage = Memory + EFI_PAGES_TO_SIZE (NumberOfPages);
+  if (IsTailGuard (GuardPage)) {
+    if (!IsMemoryGuarded (GuardPage + EFI_PAGES_TO_SIZE (1))) {
+      //
+      // If the tail Guard is not a head Guard of adjacent memory block,
+      // free it; otherwise, keep it.
+      //
+      UnsetGuardPage (GuardPage);
+    }
+  } else if (IsMemoryGuarded (GuardPage)) {
+    //
+    // 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;
+
+  Target = Start + Size - SizeRequested;
+
+  //
+  // At least one more page needed for Guard page.
+  //
+  if (Size < (SizeRequested + EFI_PAGES_TO_SIZE (1))) {
+    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;
+
+  if (Memory == NULL || NumberOfPages == NULL || *NumberOfPages == 0) {
+    return;
+  }
+
+  Start = *Memory;
+  PagesToFree = *NumberOfPages;
+
+  //
+  // Head Guard must be one page before, if any.
+  //
+  MemoryToTest = Start - EFI_PAGES_TO_SIZE (1);
+  if (IsHeadGuard (MemoryToTest)) {
+    if (!IsMemoryGuarded (MemoryToTest - EFI_PAGES_TO_SIZE (1))) {
+      //
+      // 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 if (IsMemoryGuarded (MemoryToTest)) {
+    //
+    // 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.
+  //
+  MemoryToTest = Start + EFI_PAGES_TO_SIZE (PagesToFree);
+  if (IsTailGuard (MemoryToTest)) {
+    if (!IsMemoryGuarded (MemoryToTest + EFI_PAGES_TO_SIZE (1))) {
+      //
+      // If the tail Guard is not a head Guard of adjacent memory block,
+      // free it; otherwise, keep it.
+      //
+      PagesToFree += 1;
+    }
+  } else if (IsMemoryGuarded (MemoryToTest)) {
+    //
+    // 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 ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0) {
+    //
+    // Pool head is put near the head Guard
+    //
+    return (VOID *)(UINTN)Memory;
+  }
+
+  //
+  // Pool head is put near the tail Guard
+  //
+  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
+
+  @return Address of pool head
+**/
+VOID *
+AdjustPoolHeadF (
+  IN EFI_PHYSICAL_ADDRESS    Memory
+  )
+{
+  if ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0) {
+    //
+    // Pool head is put near the head Guard
+    //
+    return (VOID *)(UINTN)Memory;
+  }
+
+  //
+  // Pool head is put near the tail Guard
+  //
+  return (VOID *)(UINTN)(Memory & ~EFI_PAGE_MASK);
+}
+
+/**
+  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 UINT64           NumberOfPages,
+  IN EFI_MEMORY_TYPE  NewType
+  )
+{
+  if (NewType == EfiConventionalMemory) {
+    AdjustMemoryF (&Start, &NumberOfPages);
+  } else {
+    AdjustMemoryA (&Start, &NumberOfPages);
+  }
+
+  return CoreConvertPages(Start, NumberOfPages, NewType);
+}
+
+/**
+  Helper function to convert a UINT64 value in binary to a string
+
+  @param[in]  Value       Value of a UINT64 integer
+  @param[in]  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
+
+  @return VOID
+**/
+VOID
+EFIAPI
+DumpGuardedMemoryBitmap (
+  VOID
+  )
+{
+  UINT64    Entries[GUARDED_HEAP_MAP_TABLE_DEPTH]
+              = GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS;
+  UINT64    Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH]
+              = GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS;
+  UINT64    *Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    TableEntry;
+  UINT64    Address;
+  INTN      Level;
+  UINTN     RepeatZero;
+  CHAR8     String[GUARDED_HEAP_MAP_ENTRY_BITS + 1];
+  CHAR8     *Ruler1 = "               3               2"
+                      "               1               0";
+  CHAR8     *Ruler2 = "FEDCBA9876543210FEDCBA9876543210"
+                      "FEDCBA9876543210FEDCBA9876543210";
+
+  if (mGuardedMemoryMap == NULL) {
+    return;
+  }
+
+  DEBUG ((DEBUG_INFO, "============================="
+                      " Guarded Memory Bitmap "
+                      "==============================\r\n"));
+  DEBUG ((DEBUG_INFO, "                  %a\r\n", Ruler1));
+  DEBUG ((DEBUG_INFO, "                  %a\r\n", Ruler2));
+
+
+  SetMem64 (Tables, sizeof(Tables), 0);
+  SetMem64 (Addresses, sizeof(Addresses), 0);
+  SetMem64 (Indices, sizeof(Indices), 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 ((
+        DEBUG_INFO,
+        "========================================="
+        "=========================================\r\n"
+        ));
+
+    } else {
+
+      TableEntry  = 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 ((DEBUG_INFO, "%016lx: %a\r\n", Address, String));
+          } else if (RepeatZero == 1) {
+            DEBUG ((DEBUG_INFO, "...             : ...\r\n"));
+          }
+          RepeatZero += 1;
+        }
+
+      } else if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {
+
+        Level            += 1;
+        Tables[Level]     = (UINT64 *)TableEntry;
+        Addresses[Level]  = Address;
+        Indices[Level]    = 0;
+        RepeatZero        = 0;
+
+        continue;
+
+      } else {
+
+        RepeatZero = 0;
+        Uint64ToBinString(TableEntry, String);
+        DEBUG ((DEBUG_INFO, "%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]);
+
+  }
+}
+
diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h
new file mode 100644
index 0000000000..26712ca93f
--- /dev/null
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h
@@ -0,0 +1,391 @@
+/** @file
+  Data type, macros and function prototypes of heap guard feature.
+
+Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#ifndef _HEAPGUARD_H_
+#define _HEAPGUARD_H_
+
+//
+// Following macros are used to define and access the guarded memory bitmap
+// table.
+//
+// To simplify the access and reduce the memory used for this table, the
+// table is constructed in the similar way as page table structure but in
+// reverse direction, i.e. from bottom growing up to top.
+//
+//    - 1-bit tracks 1 page (4KB)
+//    - 1-UINT64 map entry tracks 256KB memory
+//    - 1K-UINT64 map table tracks 256MB memory
+//    - Five levels of tables can track any address of memory of 64-bit
+//      system, like below.
+//
+//       512   *   512   *   512   *   512    *    1K   *  64b *     4K
+//    111111111 111111111 111111111 111111111 1111111111 111111 111111111111
+//    63        54        45        36        27         17     11         0
+//       9b        9b        9b        9b         10b      6b       12b
+//       L0   ->   L1   ->   L2   ->   L3   ->    L4   -> bits  ->  page
+//      1FF       1FF       1FF       1FF         3FF      3F       FFF
+//
+// L4 table has 1K * sizeof(UINT64) = 8K (2-page), which can track 256MB
+// memory. Each table of L0-L3 will be allocated when its memory address
+// range is to be tracked. Only 1-page will be allocated each time. This
+// can save memories used to establish this map table.
+//
+// For a normal configuration of system with 4G memory, two levels of tables
+// can track the whole memory, because two levels (L3+L4) of map tables have
+// already coverred 37-bit of memory address. And for a normal UEFI BIOS,
+// less than 128M memory would be consumed during boot. That means we just
+// need
+//
+//          1-page (L3) + 2-page (L4)
+//
+// memory (3 pages) to track the memory allocation works. In this case,
+// there's no need to setup L0-L2 tables.
+//
+
+//
+// Each entry occupies 8B/64b. 1-page can hold 512 entries, which spans 9
+// bits in address. (512 = 1 << 9)
+//
+#define BYTE_LENGTH_SHIFT                   3             // (8 = 1 << 3)
+
+#define GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT  \
+        (EFI_PAGE_SHIFT - BYTE_LENGTH_SHIFT)
+
+#define GUARDED_HEAP_MAP_TABLE_DEPTH        5
+
+// Use UINT64_index + bit_index_of_UINT64 to locate the bit in may
+#define GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT    6             // (64 = 1 << 6)
+
+#define GUARDED_HEAP_MAP_ENTRY_BITS         \
+        (1 << GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)
+
+#define GUARDED_HEAP_MAP_ENTRY_BYTES        \
+        (GUARDED_HEAP_MAP_ENTRY_BITS / 8)
+
+// L4 table address width: 64 - 9 * 4 - 6 - 12 = 10b
+#define GUARDED_HEAP_MAP_ENTRY_SHIFT              \
+        (GUARDED_HEAP_MAP_ENTRY_BITS              \
+         - GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 4 \
+         - GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT       \
+         - EFI_PAGE_SHIFT)
+
+// L4 table address mask: (1 << 10 - 1) = 0x3FF
+#define GUARDED_HEAP_MAP_ENTRY_MASK               \
+        ((1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) - 1)
+
+// Size of each L4 table: (1 << 10) * 8 = 8KB = 2-page
+#define GUARDED_HEAP_MAP_SIZE                     \
+        ((1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) * GUARDED_HEAP_MAP_ENTRY_BYTES)
+
+// Memory size tracked by one L4 table: 8KB * 8 * 4KB = 256MB
+#define GUARDED_HEAP_MAP_UNIT_SIZE                \
+        (GUARDED_HEAP_MAP_SIZE * 8 * EFI_PAGE_SIZE)
+
+// L4 table entry number: 8KB / 8 = 1024
+#define GUARDED_HEAP_MAP_ENTRIES_PER_UNIT         \
+        (GUARDED_HEAP_MAP_SIZE / GUARDED_HEAP_MAP_ENTRY_BYTES)
+
+// L4 table entry indexing
+#define GUARDED_HEAP_MAP_ENTRY_INDEX(Address)                       \
+        (RShiftU64 (Address, EFI_PAGE_SHIFT                         \
+                             + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)    \
+         & GUARDED_HEAP_MAP_ENTRY_MASK)
+
+// L4 table entry bit indexing
+#define GUARDED_HEAP_MAP_ENTRY_BIT_INDEX(Address)       \
+        (RShiftU64 (Address, EFI_PAGE_SHIFT)            \
+         & ((1 << GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT) - 1))
+
+//
+// Total bits (pages) tracked by one L4 table (65536-bit)
+//
+#define GUARDED_HEAP_MAP_BITS                               \
+        (1 << (GUARDED_HEAP_MAP_ENTRY_SHIFT                 \
+               + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT))
+
+//
+// Bit indexing inside the whole L4 table (0 - 65535)
+//
+#define GUARDED_HEAP_MAP_BIT_INDEX(Address)                     \
+        (RShiftU64 (Address, EFI_PAGE_SHIFT)                    \
+         & ((1 << (GUARDED_HEAP_MAP_ENTRY_SHIFT                 \
+                   + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)) - 1))
+
+//
+// Memory address bit width tracked by L4 table: 10 + 6 + 12 = 28
+//
+#define GUARDED_HEAP_MAP_TABLE_SHIFT                                      \
+        (GUARDED_HEAP_MAP_ENTRY_SHIFT + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT  \
+         + EFI_PAGE_SHIFT)
+
+//
+// Macro used to initialize the local array variable for map table traversing
+// {55, 46, 37, 28, 18}
+//
+#define GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS                                 \
+  {                                                                         \
+    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 3,  \
+    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 2,  \
+    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT,      \
+    GUARDED_HEAP_MAP_TABLE_SHIFT,                                           \
+    EFI_PAGE_SHIFT + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT                       \
+  }
+
+//
+// Masks used to extract address range of each level of table
+// {0x1FF, 0x1FF, 0x1FF, 0x1FF, 0x3FF}
+//
+#define GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS                                  \
+  {                                                                         \
+    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
+    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
+    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
+    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
+    (1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) - 1                                 \
+  }
+
+//
+// Memory type to guard (matching the related PCD definition)
+//
+#define GUARD_HEAP_TYPE_POOL        BIT0
+#define GUARD_HEAP_TYPE_PAGE        BIT1
+
+typedef struct {
+  UINT32                TailMark;
+  UINT32                HeadMark;
+  EFI_PHYSICAL_ADDRESS  Address;
+  LIST_ENTRY            Link;
+} HEAP_GUARD_NODE;
+
+EFI_STATUS
+CoreConvertPages (
+  IN UINT64           Start,
+  IN UINT64           NumberOfPages,
+  IN EFI_MEMORY_TYPE  NewType
+  );
+
+/**
+  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 UINT64           NumberOfPages,
+  IN EFI_MEMORY_TYPE  NewType
+  );
+
+/**
+  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
+  );
+
+/**
+  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
+  );
+
+/**
+  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
+  );
+
+/**
+  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
+  );
+
+/**
+  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
+  );
+
+/**
+  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 UINT64           NumberOfPages,
+  IN EFI_MEMORY_TYPE  NewType
+  );
+
+/**
+  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
+  );
+
+/**
+  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
+  );
+
+/**
+  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
+  );
+
+/**
+  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
+  );
+
+/**
+  Dump the guarded memory bit map
+
+  @return VOID
+**/
+VOID
+EFIAPI
+DumpGuardedMemoryBitmap (
+  VOID
+  );
+
+/**
+  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
+  );
+
+/**
+  Get the page base address according to pool head address
+
+  @param[in]  Memory    Head address of pool to free
+
+  @return Address of pool head
+**/
+VOID *
+AdjustPoolHeadF (
+  IN EFI_PHYSICAL_ADDRESS    Memory
+  );
+
+extern BOOLEAN mOnGuarding;
+
+#endif
diff --git a/MdeModulePkg/Core/Dxe/Mem/Imem.h b/MdeModulePkg/Core/Dxe/Mem/Imem.h
index fb53f95575..e58a5d62ba 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Imem.h
+++ b/MdeModulePkg/Core/Dxe/Mem/Imem.h
@@ -1,7 +1,7 @@
 /** @file
   Data structure and functions to allocate and free memory space.
 
-Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
 which accompanies this distribution.  The full text of the license may be found at
@@ -61,6 +61,7 @@ typedef struct {
   @param  PoolType               The type of memory for the new pool pages
   @param  NumberOfPages          No of pages to allocate
   @param  Alignment              Bits to align.
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @return The allocated memory, or NULL
 
@@ -69,7 +70,8 @@ VOID *
 CoreAllocatePoolPages (
   IN EFI_MEMORY_TYPE    PoolType,
   IN UINTN              NumberOfPages,
-  IN UINTN              Alignment
+  IN UINTN              Alignment,
+  IN BOOLEAN            NeedGuard
   );
 
 
@@ -95,6 +97,7 @@ CoreFreePoolPages (
 
   @param  PoolType               Type of pool to allocate
   @param  Size                   The amount of pool to allocate
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @return The allocate pool, or NULL
 
@@ -102,7 +105,8 @@ CoreFreePoolPages (
 VOID *
 CoreAllocatePoolI (
   IN EFI_MEMORY_TYPE  PoolType,
-  IN UINTN            Size
+  IN UINTN            Size,
+  IN BOOLEAN          NeedGuard
   );
 
 
@@ -145,6 +149,34 @@ CoreReleaseMemoryLock (
   VOID
   );
 
+/**
+  Allocates pages from the memory map.
+
+  @param  Type                   The type of allocation to perform
+  @param  MemoryType             The type of memory to turn the allocated pages
+                                 into
+  @param  NumberOfPages          The number of pages to allocate
+  @param  Memory                 A pointer to receive the base allocated memory
+                                 address
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
+
+  @return Status. On success, Memory is filled in with the base address allocated
+  @retval EFI_INVALID_PARAMETER  Parameters violate checking rules defined in
+                                 spec.
+  @retval EFI_NOT_FOUND          Could not allocate pages match the requirement.
+  @retval EFI_OUT_OF_RESOURCES   No enough pages to allocate.
+  @retval EFI_SUCCESS            Pages successfully allocated.
+
+**/
+EFI_STATUS
+EFIAPI
+CoreInternalAllocatePages (
+  IN EFI_ALLOCATE_TYPE      Type,
+  IN EFI_MEMORY_TYPE        MemoryType,
+  IN UINTN                  NumberOfPages,
+  IN OUT EFI_PHYSICAL_ADDRESS  *Memory,
+  IN BOOLEAN                NeedGuard
+  );
 
 //
 // Internal Global data
diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index 3dd6d1b4a0..648b21d429 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Page.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
@@ -14,6 +14,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 #include "DxeMain.h"
 #include "Imem.h"
+#include "HeapGuard.h"
 
 //
 // Entry for tracking the memory regions for each memory type to coalesce similar memory types
@@ -285,9 +286,12 @@ AllocateMemoryMapEntry (
     //
     // The list is empty, to allocate one page to refuel the list
     //
-    FreeDescriptorEntries = CoreAllocatePoolPages (EfiBootServicesData,
+    FreeDescriptorEntries = CoreAllocatePoolPages (
+                              EfiBootServicesData,
                               EFI_SIZE_TO_PAGES (DEFAULT_PAGE_ALLOCATION_GRANULARITY),
-                              DEFAULT_PAGE_ALLOCATION_GRANULARITY);
+                              DEFAULT_PAGE_ALLOCATION_GRANULARITY,
+                              FALSE
+                              );
     if (FreeDescriptorEntries != NULL) {
       //
       // Enque the free memmory map entries into the list
@@ -894,17 +898,41 @@ CoreConvertPagesEx (
     //
     CoreAddRange (MemType, Start, RangeEnd, Attribute);
     if (ChangingType && (MemType == EfiConventionalMemory)) {
-      //
-      // Avoid calling DEBUG_CLEAR_MEMORY() for an address of 0 because this
-      // macro will ASSERT() if address is 0.  Instead, CoreAddRange() guarantees
-      // that the page starting at address 0 is always filled with zeros.
-      //
       if (Start == 0) {
+        //
+        // Avoid calling DEBUG_CLEAR_MEMORY() for an address of 0 because this
+        // macro will ASSERT() if address is 0.  Instead, CoreAddRange()
+        // guarantees that the page starting at address 0 is always filled
+        // with zeros.
+        //
         if (RangeEnd > EFI_PAGE_SIZE) {
           DEBUG_CLEAR_MEMORY ((VOID *)(UINTN) EFI_PAGE_SIZE, (UINTN) (RangeEnd - EFI_PAGE_SIZE + 1));
         }
       } else {
-        DEBUG_CLEAR_MEMORY ((VOID *)(UINTN) Start, (UINTN) (RangeEnd - Start + 1));
+        //
+        // If Heap Guard is enabled, the page at the top and/or bottom of
+        // this memory block to free might be inaccessible. Skipping them
+        // to avoid page fault exception.
+        //
+        UINT64  StartToClear;
+        UINT64  EndToClear;
+
+        StartToClear = Start;
+        EndToClear   = RangeEnd;
+        if (PcdGet8 (PcdHeapGuardPropertyMask) & (BIT1|BIT0)) {
+          if (IsGuardPage(StartToClear)) {
+            StartToClear += EFI_PAGE_SIZE;
+          }
+          if (IsGuardPage (EndToClear)) {
+            EndToClear -= EFI_PAGE_SIZE;
+          }
+          ASSERT (EndToClear > StartToClear);
+        }
+
+        DEBUG_CLEAR_MEMORY(
+          (VOID *)(UINTN)StartToClear,
+          (UINTN)(EndToClear - StartToClear + 1)
+          );
       }
     }
 
@@ -991,6 +1019,7 @@ CoreUpdateMemoryAttributes (
   @param  NewType                The type of memory the range is going to be
                                  turned into
   @param  Alignment              Bits to align with
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @return The base address of the range, or 0 if the range was not found
 
@@ -1001,7 +1030,8 @@ CoreFindFreePagesI (
   IN UINT64           MinAddress,
   IN UINT64           NumberOfPages,
   IN EFI_MEMORY_TYPE  NewType,
-  IN UINTN            Alignment
+  IN UINTN            Alignment,
+  IN BOOLEAN          NeedGuard
   )
 {
   UINT64          NumberOfBytes;
@@ -1093,6 +1123,17 @@ CoreFindFreePagesI (
       // If this is the best match so far remember it
       //
       if (DescEnd > Target) {
+        if (NeedGuard) {
+          DescEnd = AdjustMemoryS (
+                      DescEnd + 1 - DescNumberOfBytes,
+                      DescNumberOfBytes,
+                      NumberOfBytes
+                      );
+          if (DescEnd == 0) {
+            continue;
+          }
+        }
+
         Target = DescEnd;
       }
     }
@@ -1123,6 +1164,7 @@ CoreFindFreePagesI (
   @param  NewType                The type of memory the range is going to be
                                  turned into
   @param  Alignment              Bits to align with
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @return The base address of the range, or 0 if the range was not found.
 
@@ -1132,7 +1174,8 @@ FindFreePages (
     IN UINT64           MaxAddress,
     IN UINT64           NoPages,
     IN EFI_MEMORY_TYPE  NewType,
-    IN UINTN            Alignment
+    IN UINTN            Alignment,
+    IN BOOLEAN          NeedGuard
     )
 {
   UINT64   Start;
@@ -1146,7 +1189,8 @@ FindFreePages (
               mMemoryTypeStatistics[NewType].BaseAddress, 
               NoPages, 
               NewType, 
-              Alignment
+              Alignment,
+              NeedGuard
               );
     if (Start != 0) {
       return Start;
@@ -1157,7 +1201,8 @@ FindFreePages (
   // Attempt to find free pages in the default allocation bin
   //
   if (MaxAddress >= mDefaultMaximumAddress) {
-    Start = CoreFindFreePagesI (mDefaultMaximumAddress, 0, NoPages, NewType, Alignment);
+    Start = CoreFindFreePagesI (mDefaultMaximumAddress, 0, NoPages, NewType,
+                                Alignment, NeedGuard);
     if (Start != 0) {
       if (Start < mDefaultBaseAddress) {
         mDefaultBaseAddress = Start;
@@ -1172,7 +1217,8 @@ FindFreePages (
   // address range.  If this allocation fails, then there are not enough 
   // resources anywhere to satisfy the request.
   //
-  Start = CoreFindFreePagesI (MaxAddress, 0, NoPages, NewType, Alignment);
+  Start = CoreFindFreePagesI (MaxAddress, 0, NoPages, NewType, Alignment,
+                              NeedGuard);
   if (Start != 0) {
     return Start;
   }
@@ -1187,7 +1233,7 @@ FindFreePages (
   //
   // If any memory resources were promoted, then re-attempt the allocation
   //
-  return FindFreePages (MaxAddress, NoPages, NewType, Alignment);
+  return FindFreePages (MaxAddress, NoPages, NewType, Alignment, NeedGuard);
 }
 
 
@@ -1200,6 +1246,7 @@ FindFreePages (
   @param  NumberOfPages          The number of pages to allocate
   @param  Memory                 A pointer to receive the base allocated memory
                                  address
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @return Status. On success, Memory is filled in with the base address allocated
   @retval EFI_INVALID_PARAMETER  Parameters violate checking rules defined in
@@ -1215,7 +1262,8 @@ CoreInternalAllocatePages (
   IN EFI_ALLOCATE_TYPE      Type,
   IN EFI_MEMORY_TYPE        MemoryType,
   IN UINTN                  NumberOfPages,
-  IN OUT EFI_PHYSICAL_ADDRESS  *Memory
+  IN OUT EFI_PHYSICAL_ADDRESS  *Memory,
+  IN BOOLEAN                NeedGuard
   )
 {
   EFI_STATUS      Status;
@@ -1301,7 +1349,8 @@ CoreInternalAllocatePages (
   // If not a specific address, then find an address to allocate
   //
   if (Type != AllocateAddress) {
-    Start = FindFreePages (MaxAddress, NumberOfPages, MemoryType, Alignment);
+    Start = FindFreePages (MaxAddress, NumberOfPages, MemoryType, Alignment,
+                           NeedGuard);
     if (Start == 0) {
       Status = EFI_OUT_OF_RESOURCES;
       goto Done;
@@ -1311,12 +1360,19 @@ CoreInternalAllocatePages (
   //
   // Convert pages from FreeMemory to the requested type
   //
-  Status = CoreConvertPages (Start, NumberOfPages, MemoryType);
+  if (NeedGuard) {
+    Status = CoreConvertPagesWithGuard(Start, NumberOfPages, MemoryType);
+  } else {
+    Status = CoreConvertPages(Start, NumberOfPages, MemoryType);
+  }
 
 Done:
   CoreReleaseMemoryLock ();
 
   if (!EFI_ERROR (Status)) {
+    if (NeedGuard) {
+      SetGuardForMemory (Start, NumberOfPages);
+    }
     *Memory = Start;
   }
 
@@ -1351,8 +1407,11 @@ CoreAllocatePages (
   )
 {
   EFI_STATUS  Status;
+  BOOLEAN     NeedGuard;
 
-  Status = CoreInternalAllocatePages (Type, MemoryType, NumberOfPages, Memory);
+  NeedGuard = IsPageTypeToGuard (MemoryType, Type) && !mOnGuarding;
+  Status = CoreInternalAllocatePages (Type, MemoryType, NumberOfPages, Memory,
+                                      NeedGuard);
   if (!EFI_ERROR (Status)) {
     CoreUpdateProfile (
       (EFI_PHYSICAL_ADDRESS) (UINTN) RETURN_ADDRESS (0),
@@ -1393,6 +1452,7 @@ CoreInternalFreePages (
   LIST_ENTRY      *Link;
   MEMORY_MAP      *Entry;
   UINTN           Alignment;
+  BOOLEAN         IsGuarded;
 
   //
   // Free the range
@@ -1438,14 +1498,20 @@ CoreInternalFreePages (
     *MemoryType = Entry->Type;
   }
 
-  Status = CoreConvertPages (Memory, NumberOfPages, EfiConventionalMemory);
-
-  if (EFI_ERROR (Status)) {
-    goto Done;
+  IsGuarded = IsPageTypeToGuard (Entry->Type, AllocateAnyPages) &&
+              IsMemoryGuarded (Memory);
+  if (IsGuarded) {
+    Status = CoreConvertPagesWithGuard (Memory, NumberOfPages,
+                                        EfiConventionalMemory);
+  } else {
+    Status = CoreConvertPages (Memory, NumberOfPages, EfiConventionalMemory);
   }
 
 Done:
   CoreReleaseMemoryLock ();
+  if (IsGuarded) {
+    UnsetGuardForMemory(Memory, NumberOfPages);
+  }
   return Status;
 }
 
@@ -1843,6 +1909,12 @@ Done:
 
   *MemoryMapSize = BufferSize;
 
+  DEBUG_CODE (
+    if (PcdGet8 (PcdHeapGuardPropertyMask) & (BIT1|BIT0)) {
+      DumpGuardedMemoryBitmap ();
+    }
+  );
+
   return Status;
 }
 
@@ -1854,6 +1926,7 @@ Done:
   @param  PoolType               The type of memory for the new pool pages
   @param  NumberOfPages          No of pages to allocate
   @param  Alignment              Bits to align.
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @return The allocated memory, or NULL
 
@@ -1862,7 +1935,8 @@ VOID *
 CoreAllocatePoolPages (
   IN EFI_MEMORY_TYPE    PoolType,
   IN UINTN              NumberOfPages,
-  IN UINTN              Alignment
+  IN UINTN              Alignment,
+  IN BOOLEAN            NeedGuard
   )
 {
   UINT64            Start;
@@ -1870,7 +1944,8 @@ CoreAllocatePoolPages (
   //
   // Find the pages to convert
   //
-  Start = FindFreePages (MAX_ADDRESS, NumberOfPages, PoolType, Alignment);
+  Start = FindFreePages (MAX_ADDRESS, NumberOfPages, PoolType, Alignment,
+                         NeedGuard);
 
   //
   // Convert it to boot services data
@@ -1878,7 +1953,11 @@ CoreAllocatePoolPages (
   if (Start == 0) {
     DEBUG ((DEBUG_ERROR | DEBUG_PAGE, "AllocatePoolPages: failed to allocate %d pages\n", (UINT32)NumberOfPages));
   } else {
-    CoreConvertPages (Start, NumberOfPages, PoolType);
+    if (NeedGuard) {
+      CoreConvertPagesWithGuard (Start, NumberOfPages, PoolType);
+    } else {
+      CoreConvertPages (Start, NumberOfPages, PoolType);
+    }
   }
 
   return (VOID *)(UINTN) Start;
diff --git a/MdeModulePkg/Core/Dxe/Mem/Pool.c b/MdeModulePkg/Core/Dxe/Mem/Pool.c
index dd165fea75..14aaef8250 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Pool.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Pool.c
@@ -14,6 +14,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 #include "DxeMain.h"
 #include "Imem.h"
+#include "HeapGuard.h"
 
 STATIC EFI_LOCK mPoolMemoryLock = EFI_INITIALIZE_LOCK_VARIABLE (TPL_NOTIFY);
 
@@ -169,7 +170,7 @@ LookupPoolHead (
       }
     }
 
-    Pool = CoreAllocatePoolI (EfiBootServicesData, sizeof (POOL));
+    Pool = CoreAllocatePoolI (EfiBootServicesData, sizeof (POOL), FALSE);
     if (Pool == NULL) {
       return NULL;
     }
@@ -214,7 +215,8 @@ CoreInternalAllocatePool (
   OUT VOID            **Buffer
   )
 {
-  EFI_STATUS    Status;
+  EFI_STATUS            Status;
+  BOOLEAN               NeedGuard;
 
   //
   // If it's not a valid type, fail it
@@ -238,6 +240,8 @@ CoreInternalAllocatePool (
     return EFI_OUT_OF_RESOURCES;
   }
 
+  NeedGuard = IsPoolTypeToGuard (PoolType) && !mOnGuarding;
+
   //
   // Acquire the memory lock and make the allocation
   //
@@ -246,7 +250,7 @@ CoreInternalAllocatePool (
     return EFI_OUT_OF_RESOURCES;
   }
 
-  *Buffer = CoreAllocatePoolI (PoolType, Size);
+  *Buffer = CoreAllocatePoolI (PoolType, Size, NeedGuard);
   CoreReleaseLock (&mPoolMemoryLock);
   return (*Buffer != NULL) ? EFI_SUCCESS : EFI_OUT_OF_RESOURCES;
 }
@@ -298,6 +302,7 @@ CoreAllocatePool (
   @param  PoolType               The type of memory for the new pool pages
   @param  NoPages                No of pages to allocate
   @param  Granularity            Bits to align.
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @return The allocated memory, or NULL
 
@@ -307,7 +312,8 @@ VOID *
 CoreAllocatePoolPagesI (
   IN EFI_MEMORY_TYPE    PoolType,
   IN UINTN              NoPages,
-  IN UINTN              Granularity
+  IN UINTN              Granularity,
+  IN BOOLEAN            NeedGuard
   )
 {
   VOID        *Buffer;
@@ -318,11 +324,14 @@ CoreAllocatePoolPagesI (
     return NULL;
   }
 
-  Buffer = CoreAllocatePoolPages (PoolType, NoPages, Granularity);
+  Buffer = CoreAllocatePoolPages (PoolType, NoPages, Granularity, NeedGuard);
   CoreReleaseMemoryLock ();
 
   if (Buffer != NULL) {
-    ApplyMemoryProtectionPolicy (EfiConventionalMemory, PoolType,
+    if (NeedGuard) {
+      SetGuardForMemory ((EFI_PHYSICAL_ADDRESS)Buffer, NoPages);
+    }
+    ApplyMemoryProtectionPolicy(EfiConventionalMemory, PoolType,
       (EFI_PHYSICAL_ADDRESS)(UINTN)Buffer, EFI_PAGES_TO_SIZE (NoPages));
   }
   return Buffer;
@@ -334,6 +343,7 @@ CoreAllocatePoolPagesI (
 
   @param  PoolType               Type of pool to allocate
   @param  Size                   The amount of pool to allocate
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @return The allocate pool, or NULL
 
@@ -341,7 +351,8 @@ CoreAllocatePoolPagesI (
 VOID *
 CoreAllocatePoolI (
   IN EFI_MEMORY_TYPE  PoolType,
-  IN UINTN            Size
+  IN UINTN            Size,
+  IN BOOLEAN          NeedGuard
   )
 {
   POOL        *Pool;
@@ -355,6 +366,7 @@ CoreAllocatePoolI (
   UINTN       Offset, MaxOffset;
   UINTN       NoPages;
   UINTN       Granularity;
+  BOOLEAN     HasPoolTail;
 
   ASSERT_LOCKED (&mPoolMemoryLock);
 
@@ -372,6 +384,9 @@ CoreAllocatePoolI (
   // Adjust the size by the pool header & tail overhead
   //
 
+  HasPoolTail  = !(NeedGuard &&
+                   ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) == 0));
+
   //
   // Adjusting the Size to be of proper alignment so that
   // we don't get an unaligned access fault later when
@@ -391,10 +406,16 @@ CoreAllocatePoolI (
   // If allocation is over max size, just allocate pages for the request
   // (slow)
   //
-  if (Index >= SIZE_TO_LIST (Granularity)) {
-    NoPages = EFI_SIZE_TO_PAGES(Size) + EFI_SIZE_TO_PAGES (Granularity) - 1;
+  if (Index >= SIZE_TO_LIST (Granularity) || NeedGuard) {
+    if (!HasPoolTail) {
+      Size -= sizeof (POOL_TAIL);
+    }
+    NoPages = EFI_SIZE_TO_PAGES (Size) + EFI_SIZE_TO_PAGES (Granularity) - 1;
     NoPages &= ~(UINTN)(EFI_SIZE_TO_PAGES (Granularity) - 1);
-    Head = CoreAllocatePoolPagesI (PoolType, NoPages, Granularity);
+    Head = CoreAllocatePoolPagesI (PoolType, NoPages, Granularity, NeedGuard);
+    if (NeedGuard) {
+      Head = AdjustPoolHeadA ((EFI_PHYSICAL_ADDRESS)Head, NoPages, Size);
+    }
     goto Done;
   }
 
@@ -422,7 +443,8 @@ CoreAllocatePoolI (
     //
     // Get another page
     //
-    NewPage = CoreAllocatePoolPagesI (PoolType, EFI_SIZE_TO_PAGES (Granularity), Granularity);
+    NewPage = CoreAllocatePoolPagesI (PoolType, EFI_SIZE_TO_PAGES (Granularity),
+                                      Granularity, NeedGuard);
     if (NewPage == NULL) {
       goto Done;
     }
@@ -468,30 +490,39 @@ Done:
 
   if (Head != NULL) {
 
+    //
+    // Account the allocation
+    //
+    Pool->Used += Size;
+
     //
     // If we have a pool buffer, fill in the header & tail info
     //
     Head->Signature = POOL_HEAD_SIGNATURE;
     Head->Size      = Size;
     Head->Type      = (EFI_MEMORY_TYPE) PoolType;
-    Tail            = HEAD_TO_TAIL (Head);
-    Tail->Signature = POOL_TAIL_SIGNATURE;
-    Tail->Size      = Size;
     Buffer          = Head->Data;
-    DEBUG_CLEAR_MEMORY (Buffer, Size - POOL_OVERHEAD);
+
+    if (HasPoolTail) {
+      Tail            = HEAD_TO_TAIL (Head);
+      Tail->Signature = POOL_TAIL_SIGNATURE;
+      Tail->Size      = Size;
+
+      Size -= POOL_OVERHEAD;
+    } else {
+      Size -= SIZE_OF_POOL_HEAD;
+    }
+
+    DEBUG_CLEAR_MEMORY (Buffer, Size);
 
     DEBUG ((
       DEBUG_POOL,
       "AllocatePoolI: Type %x, Addr %p (len %lx) %,ld\n", PoolType,
       Buffer,
-      (UINT64)(Size - POOL_OVERHEAD),
+      (UINT64)Size,
       (UINT64) Pool->Used
       ));
 
-    //
-    // Account the allocation
-    //
-    Pool->Used += Size;
 
   } else {
     DEBUG ((DEBUG_ERROR | DEBUG_POOL, "AllocatePool: failed to allocate %ld bytes\n", (UINT64) Size));
@@ -588,6 +619,34 @@ CoreFreePoolPagesI (
     (EFI_PHYSICAL_ADDRESS)(UINTN)Memory, EFI_PAGES_TO_SIZE (NoPages));
 }
 
+/**
+  Internal function.  Frees guarded pool pages.
+
+  @param  PoolType               The type of memory for the pool pages
+  @param  Memory                 The base address to free
+  @param  NoPages                The number of pages to free
+
+**/
+STATIC
+VOID
+CoreFreePoolPagesWithGuard (
+  IN EFI_MEMORY_TYPE        PoolType,
+  IN EFI_PHYSICAL_ADDRESS   Memory,
+  IN UINTN                  NoPages
+  )
+{
+  EFI_PHYSICAL_ADDRESS    MemoryGuarded;
+  UINTN                   NoPagesGuarded;
+
+  MemoryGuarded  = Memory;
+  NoPagesGuarded = NoPages;
+
+  AdjustMemoryF (&Memory, &NoPages);
+  CoreFreePoolPagesI (PoolType, Memory, NoPages);
+
+  UnsetGuardForMemory (MemoryGuarded, NoPagesGuarded);
+}
+
 /**
   Internal function to free a pool entry.
   Caller must have the memory lock held
@@ -616,6 +675,8 @@ CoreFreePoolI (
   UINTN       Offset;
   BOOLEAN     AllFree;
   UINTN       Granularity;
+  BOOLEAN     IsGuarded;
+  BOOLEAN     HasPoolTail;
 
   ASSERT(Buffer != NULL);
   //
@@ -628,24 +689,32 @@ CoreFreePoolI (
     return EFI_INVALID_PARAMETER;
   }
 
-  Tail = HEAD_TO_TAIL (Head);
-  ASSERT(Tail != NULL);
+  IsGuarded   = IsPoolTypeToGuard (Head->Type) &&
+                IsMemoryGuarded ((EFI_PHYSICAL_ADDRESS)Head);
+  HasPoolTail = !(IsGuarded &&
+                  ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) == 0));
 
-  //
-  // Debug
-  //
-  ASSERT (Tail->Signature == POOL_TAIL_SIGNATURE);
-  ASSERT (Head->Size == Tail->Size);
-  ASSERT_LOCKED (&mPoolMemoryLock);
+  if (HasPoolTail) {
+    Tail = HEAD_TO_TAIL (Head);
+    ASSERT (Tail != NULL);
 
-  if (Tail->Signature != POOL_TAIL_SIGNATURE) {
-    return EFI_INVALID_PARAMETER;
-  }
+    //
+    // Debug
+    //
+    ASSERT (Tail->Signature == POOL_TAIL_SIGNATURE);
+    ASSERT (Head->Size == Tail->Size);
 
-  if (Head->Size != Tail->Size) {
-    return EFI_INVALID_PARAMETER;
+    if (Tail->Signature != POOL_TAIL_SIGNATURE) {
+      return EFI_INVALID_PARAMETER;
+    }
+
+    if (Head->Size != Tail->Size) {
+      return EFI_INVALID_PARAMETER;
+    }
   }
 
+  ASSERT_LOCKED (&mPoolMemoryLock);
+
   //
   // Determine the pool type and account for it
   //
@@ -680,14 +749,27 @@ CoreFreePoolI (
   //
   // If it's not on the list, it must be pool pages
   //
-  if (Index >= SIZE_TO_LIST (Granularity)) {
+  if (Index >= SIZE_TO_LIST (Granularity) || IsGuarded) {
 
     //
     // Return the memory pages back to free memory
     //
-    NoPages = EFI_SIZE_TO_PAGES(Size) + EFI_SIZE_TO_PAGES (Granularity) - 1;
+    NoPages = EFI_SIZE_TO_PAGES (Size) + EFI_SIZE_TO_PAGES (Granularity) - 1;
     NoPages &= ~(UINTN)(EFI_SIZE_TO_PAGES (Granularity) - 1);
-    CoreFreePoolPagesI (Pool->MemoryType, (EFI_PHYSICAL_ADDRESS) (UINTN) Head, NoPages);
+    if (IsGuarded) {
+      Head = AdjustPoolHeadF ((EFI_PHYSICAL_ADDRESS)(UINTN)Head);
+      CoreFreePoolPagesWithGuard (
+        Pool->MemoryType,
+        (EFI_PHYSICAL_ADDRESS)(UINTN)Head,
+        NoPages
+        );
+    } else {
+      CoreFreePoolPagesI (
+        Pool->MemoryType,
+        (EFI_PHYSICAL_ADDRESS)(UINTN)Head,
+        NoPages
+        );
+    }
 
   } else {
 
-- 
2.14.1.windows.1

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