From: Michael Kubacki <michael.kubacki@microsoft.com>

GetNextEntryAttribute() is currently applying a 64-bit mask
(TT_ATTRIBUTES_MASK) to a 32-bit descriptor value (EntryType).
The original descriptor was 64 bits containing the upper and
lower attributes which are included in TT_ATTRIBUTES_MASK.

The PrevEntryAttribute parameter is also a UINT32, but passed to
PageAttributeToGcdAttribute() for a UINT64 parameter where the
function checks masks in the upper 32 bits of the integer value:

  PageAttributeToGcdAttribute (*PrevEntryAttribute)
  ...
  STATIC
  UINT64
  PageAttributeToGcdAttribute (
    IN UINT64  PageAttributes
    )
  ...
  if ((PageAttributes & (TT_PXN_MASK | TT_UXN_MASK)) != 0) {
    GcdAttributes |= EFI_MEMORY_XP;
  }
  ...
  #define TT_PXN_MASK  BIT53
  #define TT_UXN_MASK  BIT54  // EL1&0

This change removes UINT32 intermediary values. For EntryType,
eliminating an unncessary cast. For EntryAttribute, preserving the
upper and lower attributes for evaluation in
PageAttributeToGcdAttribute().

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
---
 ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c b/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
index 4555fdb5c2c8..ff14c2f814b2 100644
--- a/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
+++ b/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
@@ -13,7 +13,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/MemoryAllocationLib.h>
 #include "CpuDxe.h"
 
-#define INVALID_ENTRY  ((UINT32)~0)
+#define INVALID_ENTRY  ((UINT64)~0)
 
 #define MIN_T0SZ        16
 #define BITS_PER_LEVEL  9
@@ -169,14 +169,14 @@ GetNextEntryAttribute (
   IN     UINTN   EntryCount,
   IN     UINTN   TableLevel,
   IN     UINT64  BaseAddress,
-  IN OUT UINT32  *PrevEntryAttribute,
+  IN OUT UINT64  *PrevEntryAttribute,
   IN OUT UINT64  *StartGcdRegion
   )
 {
   UINTN                            Index;
   UINT64                           Entry;
-  UINT32                           EntryAttribute;
-  UINT32                           EntryType;
+  UINT64                           EntryAttribute;
+  UINT64                           EntryType;
   EFI_STATUS                       Status;
   UINTN                            NumberOfDescriptors;
   EFI_GCD_MEMORY_SPACE_DESCRIPTOR  *MemorySpaceMap;
@@ -195,8 +195,8 @@ GetNextEntryAttribute (
   // the subsequent ones should be filled up
   for (Index = 0; Index < EntryCount; Index++) {
     Entry          = TableAddress[Index];
-    EntryType      = (UINT32)(Entry & TT_TYPE_MASK);
-    EntryAttribute = (UINT32)(Entry & TT_ATTRIBUTES_MASK);
+    EntryType      = Entry & TT_TYPE_MASK;
+    EntryAttribute = Entry & TT_ATTRIBUTES_MASK;
 
     // If Entry is a Table Descriptor type entry then go through the sub-level table
     if ((EntryType == TT_TYPE_BLOCK_ENTRY) ||
@@ -271,7 +271,7 @@ SyncCacheConfig (
   )
 {
   EFI_STATUS                       Status;
-  UINT32                           PageAttribute;
+  UINT64                           PageAttribute;
   UINT64                           *FirstLevelTableAddress;
   UINTN                            TableLevel;
   UINTN                            TableCount;
-- 
2.42.0.windows.2



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