X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=MdeModulePkg%2FCore%2FDxe%2FMem%2FHeapGuard.c;h=752befa44d064854c2ffa477137c627847e935ac;hp=98d597b180e6ad3b9ea8f0b18e7f15cdbee3e0ea;hb=f9ebb0b131967e24f58ec25aff0a50bc0215329e;hpb=94edadf502bd0e61f00bb08a5df2e078af54a770

diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
index 98d597b180..752befa44d 100644
--- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
@@ -373,7 +373,7 @@ ClearGuardedMemoryBits (
   @param[in]  Address       Memory address to retrieve from.
   @param[in]  NumberOfPages Number of pages to retrieve.
 
-  @return VOID.
+  @return An integer containing the guarded memory bitmap.
 **/
 UINTN
 GetGuardedMemoryBits (
@@ -501,8 +501,13 @@ IsGuardPage (
 {
   UINTN       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 == 0b001) || (BitMap == 0b100) || (BitMap == 0b101));
+  return ((BitMap == BIT0) || (BitMap == BIT2) || (BitMap == (BIT2 | BIT0)));
 }
 
 /**
@@ -519,7 +524,7 @@ IsHeadGuard (
   IN EFI_PHYSICAL_ADDRESS    Address
   )
 {
-  return (GetGuardedMemoryBits (Address, 2) == 0b10);
+  return (GetGuardedMemoryBits (Address, 2) == BIT1);
 }
 
 /**
@@ -536,7 +541,7 @@ IsTailGuard (
   IN EFI_PHYSICAL_ADDRESS    Address
   )
 {
-  return (GetGuardedMemoryBits (Address - EFI_PAGE_SIZE, 2) == 0b01);
+  return (GetGuardedMemoryBits (Address - EFI_PAGE_SIZE, 2) == BIT0);
 }
 
 /**