[edk2-devel] [PATCH v4 04/11] ArmPkg/ArmMmuLib ARM: Isolate the access flag from AP mask

Ard Biesheuvel ardb at kernel.org
Thu Feb 9 13:59:29 UTC 2023


Split the ARM permission fields in the short descriptors into an access
flag and AP[2:1] as per the recommendation in the ARM ARM. This makes
the access flag available separately, which allows us to implement
EFI_MEMORY_RP memory analogous to how it will be implemented for
AArch64.

Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
---
 ArmPkg/Drivers/CpuDxe/Arm/Mmu.c                 | 47 ++++++++++----------
 ArmPkg/Include/Chipset/ArmV7Mmu.h               | 40 +++++++++++------
 ArmPkg/Library/ArmLib/Arm/ArmV7Support.S        |  2 +
 ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibConvert.c |  1 +
 ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibUpdate.c  | 12 ++++-
 5 files changed, 63 insertions(+), 39 deletions(-)

diff --git a/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c b/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
index 8eb1f71395f5..07faab8216ec 100644
--- a/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
+++ b/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
@@ -50,30 +50,27 @@ SectionToGcdAttributes (
 
   // determine protection attributes
   switch (SectionAttributes & TT_DESCRIPTOR_SECTION_AP_MASK) {
-    case TT_DESCRIPTOR_SECTION_AP_NO_NO: // no read, no write
-      // *GcdAttributes |= EFI_MEMORY_RO | EFI_MEMORY_RP;
-      break;
-
-    case TT_DESCRIPTOR_SECTION_AP_RW_NO:
+    case TT_DESCRIPTOR_SECTION_AP_NO_RW:
     case TT_DESCRIPTOR_SECTION_AP_RW_RW:
       // normal read/write access, do not add additional attributes
       break;
 
     // read only cases map to write-protect
-    case TT_DESCRIPTOR_SECTION_AP_RO_NO:
+    case TT_DESCRIPTOR_SECTION_AP_NO_RO:
     case TT_DESCRIPTOR_SECTION_AP_RO_RO:
       *GcdAttributes |= EFI_MEMORY_RO;
       break;
-
-    default:
-      return EFI_UNSUPPORTED;
   }
 
   // now process eXectue Never attribute
-  if ((SectionAttributes & TT_DESCRIPTOR_SECTION_XN_MASK) != 0 ) {
+  if ((SectionAttributes & TT_DESCRIPTOR_SECTION_XN_MASK) != 0) {
     *GcdAttributes |= EFI_MEMORY_XP;
   }
 
+  if ((SectionAttributes & TT_DESCRIPTOR_SECTION_AF) == 0) {
+    *GcdAttributes |= EFI_MEMORY_RP;
+  }
+
   return EFI_SUCCESS;
 }
 
@@ -114,30 +111,27 @@ PageToGcdAttributes (
 
   // determine protection attributes
   switch (PageAttributes & TT_DESCRIPTOR_PAGE_AP_MASK) {
-    case TT_DESCRIPTOR_PAGE_AP_NO_NO: // no read, no write
-      // *GcdAttributes |= EFI_MEMORY_RO | EFI_MEMORY_RP;
-      break;
-
-    case TT_DESCRIPTOR_PAGE_AP_RW_NO:
+    case TT_DESCRIPTOR_PAGE_AP_NO_RW:
     case TT_DESCRIPTOR_PAGE_AP_RW_RW:
       // normal read/write access, do not add additional attributes
       break;
 
     // read only cases map to write-protect
-    case TT_DESCRIPTOR_PAGE_AP_RO_NO:
+    case TT_DESCRIPTOR_PAGE_AP_NO_RO:
     case TT_DESCRIPTOR_PAGE_AP_RO_RO:
       *GcdAttributes |= EFI_MEMORY_RO;
       break;
-
-    default:
-      return EFI_UNSUPPORTED;
   }
 
   // now process eXectue Never attribute
-  if ((PageAttributes & TT_DESCRIPTOR_PAGE_XN_MASK) != 0 ) {
+  if ((PageAttributes & TT_DESCRIPTOR_PAGE_XN_MASK) != 0) {
     *GcdAttributes |= EFI_MEMORY_XP;
   }
 
+  if ((PageAttributes & TT_DESCRIPTOR_PAGE_AF) == 0) {
+    *GcdAttributes |= EFI_MEMORY_RP;
+  }
+
   return EFI_SUCCESS;
 }
 
@@ -166,6 +160,7 @@ SyncCacheConfigPage (
   // Convert SectionAttributes into PageAttributes
   NextPageAttributes =
     TT_DESCRIPTOR_CONVERT_TO_PAGE_CACHE_POLICY (*NextSectionAttributes) |
+    TT_DESCRIPTOR_CONVERT_TO_PAGE_AF (*NextSectionAttributes) |
     TT_DESCRIPTOR_CONVERT_TO_PAGE_AP (*NextSectionAttributes);
 
   // obtain page table base
@@ -174,7 +169,7 @@ SyncCacheConfigPage (
   for (i = 0; i < TRANSLATION_TABLE_PAGE_COUNT; i++) {
     if ((SecondLevelTable[i] & TT_DESCRIPTOR_PAGE_TYPE_MASK) == TT_DESCRIPTOR_PAGE_TYPE_PAGE) {
       // extract attributes (cacheability and permissions)
-      PageAttributes = SecondLevelTable[i] & (TT_DESCRIPTOR_PAGE_CACHE_POLICY_MASK | TT_DESCRIPTOR_PAGE_AP_MASK);
+      PageAttributes = SecondLevelTable[i] & (TT_DESCRIPTOR_PAGE_CACHE_POLICY_MASK | TT_DESCRIPTOR_PAGE_AP_MASK | TT_DESCRIPTOR_PAGE_AF);
 
       if (NextPageAttributes == 0) {
         // start on a new region
@@ -213,6 +208,7 @@ SyncCacheConfigPage (
   // Convert back PageAttributes into SectionAttributes
   *NextSectionAttributes =
     TT_DESCRIPTOR_CONVERT_TO_SECTION_CACHE_POLICY (NextPageAttributes) |
+    TT_DESCRIPTOR_CONVERT_TO_SECTION_AF (NextPageAttributes) |
     TT_DESCRIPTOR_CONVERT_TO_SECTION_AP (NextPageAttributes);
 
   return EFI_SUCCESS;
@@ -256,14 +252,14 @@ SyncCacheConfig (
   FirstLevelTable = (ARM_FIRST_LEVEL_DESCRIPTOR *)(ArmGetTTBR0BaseAddress ());
 
   // Get the first region
-  NextSectionAttributes = FirstLevelTable[0] & (TT_DESCRIPTOR_SECTION_CACHE_POLICY_MASK | TT_DESCRIPTOR_SECTION_AP_MASK);
+  NextSectionAttributes = FirstLevelTable[0] & (TT_DESCRIPTOR_SECTION_CACHE_POLICY_MASK | TT_DESCRIPTOR_SECTION_AP_MASK | TT_DESCRIPTOR_SECTION_AF);
 
   // iterate through each 1MB descriptor
   NextRegionBase = NextRegionLength = 0;
   for (i = 0; i < TRANSLATION_TABLE_SECTION_COUNT; i++) {
     if ((FirstLevelTable[i] & TT_DESCRIPTOR_SECTION_TYPE_MASK) == TT_DESCRIPTOR_SECTION_TYPE_SECTION) {
       // extract attributes (cacheability and permissions)
-      SectionAttributes = FirstLevelTable[i] & (TT_DESCRIPTOR_SECTION_CACHE_POLICY_MASK | TT_DESCRIPTOR_SECTION_AP_MASK);
+      SectionAttributes = FirstLevelTable[i] & (TT_DESCRIPTOR_SECTION_CACHE_POLICY_MASK | TT_DESCRIPTOR_SECTION_AP_MASK | TT_DESCRIPTOR_SECTION_AF);
 
       if (NextSectionAttributes == 0) {
         // start on a new region
@@ -383,6 +379,10 @@ EfiAttributeToArmAttribute (
     ArmAttributes |= TT_DESCRIPTOR_SECTION_XN_MASK;
   }
 
+  if ((EfiAttributes & EFI_MEMORY_RP) == 0) {
+    ArmAttributes |= TT_DESCRIPTOR_SECTION_AF;
+  }
+
   return ArmAttributes;
 }
 
@@ -482,6 +482,7 @@ GetMemoryRegion (
     *RegionAttributes = TT_DESCRIPTOR_CONVERT_TO_SECTION_CACHE_POLICY (PageAttributes) |
                         TT_DESCRIPTOR_CONVERT_TO_SECTION_S (PageAttributes) |
                         TT_DESCRIPTOR_CONVERT_TO_SECTION_XN (PageAttributes) |
+                        TT_DESCRIPTOR_CONVERT_TO_SECTION_AF (PageAttributes) |
                         TT_DESCRIPTOR_CONVERT_TO_SECTION_AP (PageAttributes);
   }
 
diff --git a/ArmPkg/Include/Chipset/ArmV7Mmu.h b/ArmPkg/Include/Chipset/ArmV7Mmu.h
index e0219747df86..da4f3160f8ff 100644
--- a/ArmPkg/Include/Chipset/ArmV7Mmu.h
+++ b/ArmPkg/Include/Chipset/ArmV7Mmu.h
@@ -80,21 +80,21 @@
 #define TT_DESCRIPTOR_PAGE_S_NOT_SHARED  (0UL << 10)
 #define TT_DESCRIPTOR_PAGE_S_SHARED      (1UL << 10)
 
-#define TT_DESCRIPTOR_SECTION_AP_MASK   ((1UL << 15) | (3UL << 10))
-#define TT_DESCRIPTOR_SECTION_AP_NO_NO  ((0UL << 15) | (0UL << 10))
-#define TT_DESCRIPTOR_SECTION_AP_RW_NO  ((0UL << 15) | (1UL << 10))
-#define TT_DESCRIPTOR_SECTION_AP_RW_RO  ((0UL << 15) | (2UL << 10))
-#define TT_DESCRIPTOR_SECTION_AP_RW_RW  ((0UL << 15) | (3UL << 10))
-#define TT_DESCRIPTOR_SECTION_AP_RO_NO  ((1UL << 15) | (1UL << 10))
-#define TT_DESCRIPTOR_SECTION_AP_RO_RO  ((1UL << 15) | (3UL << 10))
+#define TT_DESCRIPTOR_SECTION_AP_MASK   ((1UL << 15) | (1UL << 11))
+#define TT_DESCRIPTOR_SECTION_AP_NO_RW  ((0UL << 15) | (0UL << 11))
+#define TT_DESCRIPTOR_SECTION_AP_RW_RW  ((0UL << 15) | (1UL << 11))
+#define TT_DESCRIPTOR_SECTION_AP_NO_RO  ((1UL << 15) | (0UL << 11))
+#define TT_DESCRIPTOR_SECTION_AP_RO_RO  ((1UL << 15) | (1UL << 11))
 
-#define TT_DESCRIPTOR_PAGE_AP_MASK   ((1UL << 9) | (3UL << 4))
-#define TT_DESCRIPTOR_PAGE_AP_NO_NO  ((0UL << 9) | (0UL << 4))
-#define TT_DESCRIPTOR_PAGE_AP_RW_NO  ((0UL << 9) | (1UL << 4))
-#define TT_DESCRIPTOR_PAGE_AP_RW_RO  ((0UL << 9) | (2UL << 4))
-#define TT_DESCRIPTOR_PAGE_AP_RW_RW  ((0UL << 9) | (3UL << 4))
-#define TT_DESCRIPTOR_PAGE_AP_RO_NO  ((1UL << 9) | (1UL << 4))
-#define TT_DESCRIPTOR_PAGE_AP_RO_RO  ((1UL << 9) | (3UL << 4))
+#define TT_DESCRIPTOR_SECTION_AF  (1UL << 10)
+
+#define TT_DESCRIPTOR_PAGE_AP_MASK   ((1UL << 9) | (1UL << 5))
+#define TT_DESCRIPTOR_PAGE_AP_NO_RW  ((0UL << 9) | (0UL << 5))
+#define TT_DESCRIPTOR_PAGE_AP_RW_RW  ((0UL << 9) | (1UL << 5))
+#define TT_DESCRIPTOR_PAGE_AP_NO_RO  ((1UL << 9) | (0UL << 5))
+#define TT_DESCRIPTOR_PAGE_AP_RO_RO  ((1UL << 9) | (1UL << 5))
+
+#define TT_DESCRIPTOR_PAGE_AF  (1UL << 4)
 
 #define TT_DESCRIPTOR_SECTION_XN_MASK  (0x1UL << 4)
 #define TT_DESCRIPTOR_PAGE_XN_MASK     (0x1UL << 0)
@@ -124,20 +124,24 @@
 #define TT_DESCRIPTOR_CONVERT_TO_PAGE_AP(Desc)            ((((Desc) & TT_DESCRIPTOR_SECTION_AP_MASK) >> 6) & TT_DESCRIPTOR_PAGE_AP_MASK)
 #define TT_DESCRIPTOR_CONVERT_TO_PAGE_NG(Desc)            ((((Desc) & TT_DESCRIPTOR_SECTION_NG_MASK) >> 6) & TT_DESCRIPTOR_PAGE_NG_MASK)
 #define TT_DESCRIPTOR_CONVERT_TO_PAGE_S(Desc)             ((((Desc) & TT_DESCRIPTOR_SECTION_S_MASK) >> 6) & TT_DESCRIPTOR_PAGE_S_MASK)
+#define TT_DESCRIPTOR_CONVERT_TO_PAGE_AF(Desc)            ((((Desc) & TT_DESCRIPTOR_SECTION_AF) >> 6) & TT_DESCRIPTOR_PAGE_AF)
 #define TT_DESCRIPTOR_CONVERT_TO_PAGE_XN(Desc)            ((((Desc) & TT_DESCRIPTOR_SECTION_XN_MASK) >> 4) & TT_DESCRIPTOR_PAGE_XN_MASK)
 #define TT_DESCRIPTOR_CONVERT_TO_PAGE_CACHE_POLICY(Desc)  ((((Desc) & (0x3 << 12)) >> 6) | (Desc & (0x3 << 2)))
 
 #define TT_DESCRIPTOR_CONVERT_TO_SECTION_AP(Desc)            ((((Desc) & TT_DESCRIPTOR_PAGE_AP_MASK) << 6) & TT_DESCRIPTOR_SECTION_AP_MASK)
 #define TT_DESCRIPTOR_CONVERT_TO_SECTION_S(Desc)             ((((Desc) & TT_DESCRIPTOR_PAGE_S_MASK) << 6) & TT_DESCRIPTOR_SECTION_S_MASK)
+#define TT_DESCRIPTOR_CONVERT_TO_SECTION_AF(Desc)            ((((Desc) & TT_DESCRIPTOR_PAGE_AF) << 6) & TT_DESCRIPTOR_SECTION_AF)
 #define TT_DESCRIPTOR_CONVERT_TO_SECTION_XN(Desc)            ((((Desc) & TT_DESCRIPTOR_PAGE_XN_MASK) << 4) & TT_DESCRIPTOR_SECTION_XN_MASK)
 #define TT_DESCRIPTOR_CONVERT_TO_SECTION_CACHE_POLICY(Desc)  ((((Desc) & (0x3 << 6)) << 6) | (Desc & (0x3 << 2)))
 
 #define TT_DESCRIPTOR_SECTION_ATTRIBUTE_MASK  (TT_DESCRIPTOR_SECTION_NS_MASK | TT_DESCRIPTOR_SECTION_NG_MASK |               \
                                                              TT_DESCRIPTOR_SECTION_S_MASK | TT_DESCRIPTOR_SECTION_AP_MASK | \
+                                                             TT_DESCRIPTOR_SECTION_AF | \
                                                              TT_DESCRIPTOR_SECTION_XN_MASK | TT_DESCRIPTOR_SECTION_CACHE_POLICY_MASK)
 
 #define TT_DESCRIPTOR_PAGE_ATTRIBUTE_MASK  (TT_DESCRIPTOR_PAGE_NG_MASK | TT_DESCRIPTOR_PAGE_S_MASK |                  \
                                                              TT_DESCRIPTOR_PAGE_AP_MASK | TT_DESCRIPTOR_PAGE_XN_MASK | \
+                                                             TT_DESCRIPTOR_PAGE_AF | \
                                                              TT_DESCRIPTOR_PAGE_CACHE_POLICY_MASK)
 
 #define TT_DESCRIPTOR_SECTION_DOMAIN_MASK  (0x0FUL << 5)
@@ -159,6 +163,7 @@
                                                             TT_DESCRIPTOR_SECTION_S_SHARED                          | \
                                                             TT_DESCRIPTOR_SECTION_DOMAIN(0)                         | \
                                                             TT_DESCRIPTOR_SECTION_AP_RW_RW                          | \
+                                                            TT_DESCRIPTOR_SECTION_AF                                | \
                                                             TT_DESCRIPTOR_SECTION_CACHE_POLICY_WRITE_BACK_ALLOC)
 #define TT_DESCRIPTOR_SECTION_WRITE_THROUGH(NonSecure)  (TT_DESCRIPTOR_SECTION_TYPE_SECTION                                                           |     \
                                                             ((NonSecure) ?  TT_DESCRIPTOR_SECTION_NS : 0)    | \
@@ -166,6 +171,7 @@
                                                             TT_DESCRIPTOR_SECTION_S_SHARED                          | \
                                                             TT_DESCRIPTOR_SECTION_DOMAIN(0)                         | \
                                                             TT_DESCRIPTOR_SECTION_AP_RW_RW                          | \
+                                                            TT_DESCRIPTOR_SECTION_AF                                | \
                                                             TT_DESCRIPTOR_SECTION_CACHE_POLICY_WRITE_THROUGH_NO_ALLOC)
 #define TT_DESCRIPTOR_SECTION_DEVICE(NonSecure)         (TT_DESCRIPTOR_SECTION_TYPE_SECTION                                                           |     \
                                                             ((NonSecure) ?  TT_DESCRIPTOR_SECTION_NS : 0)    | \
@@ -174,6 +180,7 @@
                                                             TT_DESCRIPTOR_SECTION_DOMAIN(0)                         | \
                                                             TT_DESCRIPTOR_SECTION_AP_RW_RW                          | \
                                                             TT_DESCRIPTOR_SECTION_XN_MASK                           | \
+                                                            TT_DESCRIPTOR_SECTION_AF                                | \
                                                             TT_DESCRIPTOR_SECTION_CACHE_POLICY_SHAREABLE_DEVICE)
 #define TT_DESCRIPTOR_SECTION_UNCACHED(NonSecure)       (TT_DESCRIPTOR_SECTION_TYPE_SECTION                                                           |    \
                                                            ((NonSecure) ?  TT_DESCRIPTOR_SECTION_NS : 0)    | \
@@ -181,28 +188,33 @@
                                                            TT_DESCRIPTOR_SECTION_S_NOT_SHARED                      | \
                                                            TT_DESCRIPTOR_SECTION_DOMAIN(0)                         | \
                                                            TT_DESCRIPTOR_SECTION_AP_RW_RW                          | \
+                                                            TT_DESCRIPTOR_SECTION_AF                                | \
                                                            TT_DESCRIPTOR_SECTION_CACHE_POLICY_NON_CACHEABLE)
 
 #define TT_DESCRIPTOR_PAGE_WRITE_BACK     (TT_DESCRIPTOR_PAGE_TYPE_PAGE                                                           |          \
                                                         TT_DESCRIPTOR_PAGE_NG_GLOBAL                                                      | \
                                                         TT_DESCRIPTOR_PAGE_S_SHARED                                                       | \
                                                         TT_DESCRIPTOR_PAGE_AP_RW_RW                                                       | \
+                                                        TT_DESCRIPTOR_PAGE_AF                                                             | \
                                                         TT_DESCRIPTOR_PAGE_CACHE_POLICY_WRITE_BACK_ALLOC)
 #define TT_DESCRIPTOR_PAGE_WRITE_THROUGH  (TT_DESCRIPTOR_PAGE_TYPE_PAGE                                                           |          \
                                                         TT_DESCRIPTOR_PAGE_NG_GLOBAL                                                      | \
                                                         TT_DESCRIPTOR_PAGE_S_SHARED                                                       | \
                                                         TT_DESCRIPTOR_PAGE_AP_RW_RW                                                       | \
+                                                        TT_DESCRIPTOR_PAGE_AF                                                             | \
                                                         TT_DESCRIPTOR_PAGE_CACHE_POLICY_WRITE_THROUGH_NO_ALLOC)
 #define TT_DESCRIPTOR_PAGE_DEVICE         (TT_DESCRIPTOR_PAGE_TYPE_PAGE                                                           |          \
                                                         TT_DESCRIPTOR_PAGE_NG_GLOBAL                                                      | \
                                                         TT_DESCRIPTOR_PAGE_S_NOT_SHARED                                                   | \
                                                         TT_DESCRIPTOR_PAGE_AP_RW_RW                                                       | \
+                                                        TT_DESCRIPTOR_PAGE_AF                                                             | \
                                                         TT_DESCRIPTOR_PAGE_XN_MASK                                                        | \
                                                         TT_DESCRIPTOR_PAGE_CACHE_POLICY_SHAREABLE_DEVICE)
 #define TT_DESCRIPTOR_PAGE_UNCACHED       (TT_DESCRIPTOR_PAGE_TYPE_PAGE                                                           |          \
                                                         TT_DESCRIPTOR_PAGE_NG_GLOBAL                                                      | \
                                                         TT_DESCRIPTOR_PAGE_S_NOT_SHARED                                                   | \
                                                         TT_DESCRIPTOR_PAGE_AP_RW_RW                                                       | \
+                                                        TT_DESCRIPTOR_PAGE_AF                                                             | \
                                                         TT_DESCRIPTOR_PAGE_CACHE_POLICY_NON_CACHEABLE)
 
 // First Level Descriptors
diff --git a/ArmPkg/Library/ArmLib/Arm/ArmV7Support.S b/ArmPkg/Library/ArmLib/Arm/ArmV7Support.S
index 4925f6628e1e..1f396adffc11 100644
--- a/ArmPkg/Library/ArmLib/Arm/ArmV7Support.S
+++ b/ArmPkg/Library/ArmLib/Arm/ArmV7Support.S
@@ -16,6 +16,7 @@
 .set CTRL_C_BIT,  (1 << 2)
 .set CTRL_B_BIT,  (1 << 7)
 .set CTRL_I_BIT,  (1 << 12)
+.set CTRL_AFE_BIT,(1 << 29)
 
 
 ASM_FUNC(ArmInvalidateDataCacheEntryByMVA)
@@ -64,6 +65,7 @@ ASM_FUNC(ArmInvalidateInstructionCache)
 ASM_FUNC(ArmEnableMmu)
   mrc     p15,0,R0,c1,c0,0
   orr     R0,R0,#1
+  orr     R0,R0,#CTRL_AFE_BIT
   mcr     p15,0,R0,c1,c0,0
   dsb
   isb
diff --git a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibConvert.c b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibConvert.c
index 6e2f08a7ce15..52dbfd714029 100644
--- a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibConvert.c
+++ b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibConvert.c
@@ -23,6 +23,7 @@ ConvertSectionAttributesToPageAttributes (
   PageAttributes  = 0;
   PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_CACHE_POLICY (SectionAttributes);
   PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_AP (SectionAttributes);
+  PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_AF (SectionAttributes);
   PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_XN (SectionAttributes);
   PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_NG (SectionAttributes);
   PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_S (SectionAttributes);
diff --git a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibUpdate.c b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibUpdate.c
index 12d0f4c30f8e..484c67476619 100644
--- a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibUpdate.c
+++ b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibUpdate.c
@@ -104,7 +104,7 @@ UpdatePageEntries (
 
   // EntryMask: bitmask of values to change (1 = change this value, 0 = leave alone)
   // EntryValue: values at bit positions specified by EntryMask
-  EntryMask = TT_DESCRIPTOR_PAGE_TYPE_MASK | TT_DESCRIPTOR_PAGE_AP_MASK | TT_DESCRIPTOR_PAGE_XN_MASK;
+  EntryMask = TT_DESCRIPTOR_PAGE_TYPE_MASK | TT_DESCRIPTOR_PAGE_AP_MASK | TT_DESCRIPTOR_PAGE_XN_MASK | TT_DESCRIPTOR_PAGE_AF;
   EntryValue = TT_DESCRIPTOR_PAGE_TYPE_PAGE;
 
   // Although the PI spec is unclear on this, the GCD guarantees that only
@@ -138,6 +138,10 @@ UpdatePageEntries (
     return EFI_UNSUPPORTED;
   }
 
+  if ((Attributes & EFI_MEMORY_RP) == 0) {
+    EntryValue |= TT_DESCRIPTOR_PAGE_AF;
+  }
+
   if ((Attributes & EFI_MEMORY_RO) != 0) {
     EntryValue |= TT_DESCRIPTOR_PAGE_AP_RO_RO;
   } else {
@@ -237,7 +241,7 @@ UpdateSectionEntries (
 
   // Make sure we handle a section range that is unmapped
   EntryMask = TT_DESCRIPTOR_SECTION_TYPE_MASK | TT_DESCRIPTOR_SECTION_XN_MASK |
-              TT_DESCRIPTOR_SECTION_AP_MASK;
+              TT_DESCRIPTOR_SECTION_AP_MASK | TT_DESCRIPTOR_SECTION_AF;
   EntryValue = TT_DESCRIPTOR_SECTION_TYPE_SECTION;
 
   // Although the PI spec is unclear on this, the GCD guarantees that only
@@ -281,6 +285,10 @@ UpdateSectionEntries (
     EntryValue |= TT_DESCRIPTOR_SECTION_XN_MASK;
   }
 
+  if ((Attributes & EFI_MEMORY_RP) == 0) {
+    EntryValue |= TT_DESCRIPTOR_SECTION_AF;
+  }
+
   // obtain page table base
   FirstLevelTable = (ARM_FIRST_LEVEL_DESCRIPTOR *)ArmGetTTBR0BaseAddress ();
 
-- 
2.39.1



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