X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=MdeModulePkg%2FCore%2FDxe%2FMisc%2FMemoryProtection.c;h=a4705bc7ce343f002fb933829e9cecfaa3ec7987;hp=862593f562ca7defed3e1e41ad732443037b4458;hb=9b17c6511d50db493c49324aaf81c50c3676a111;hpb=c44218e5f40880e3100bdf4d112672e8dd56b94a

diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
index 862593f562..a4705bc7ce 100644
--- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
+++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
@@ -845,10 +845,24 @@ InitializeDxeNxMemoryProtectionPolicy (
 
     Attributes = GetPermissionAttributeForMemoryType (MemoryMapEntry->Type);
     if (Attributes != 0) {
-      SetUefiImageMemoryAttributes (
-        MemoryMapEntry->PhysicalStart,
-        LShiftU64 (MemoryMapEntry->NumberOfPages, EFI_PAGE_SHIFT),
-        Attributes);
+      if (MemoryMapEntry->PhysicalStart == 0 &&
+          PcdGet8 (PcdNullPointerDetectionPropertyMask) != 0) {
+
+        ASSERT (MemoryMapEntry->NumberOfPages > 0);
+        //
+        // Skip page 0 if NULL pointer detection is enabled to avoid attributes
+        // overwritten.
+        //
+        SetUefiImageMemoryAttributes (
+          MemoryMapEntry->PhysicalStart + EFI_PAGE_SIZE,
+          LShiftU64 (MemoryMapEntry->NumberOfPages - 1, EFI_PAGE_SHIFT),
+          Attributes);
+      } else {
+        SetUefiImageMemoryAttributes (
+          MemoryMapEntry->PhysicalStart,
+          LShiftU64 (MemoryMapEntry->NumberOfPages, EFI_PAGE_SHIFT),
+          Attributes);
+      }
     }
     MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize);
   }