From 5fc899535e5195247258aac3f43e93967543d34d Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Sat, 7 Mar 2020 12:44:16 +0100
Subject: [PATCH] ArmPkg/ArmMmuLib AARCH64: use helpers to determine table
 entry types

Given how the meaning of the attribute bits for page table entry types
is slightly awkward, and changes between levels, add some helpers to
abstract from this.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
Reviewed-by: Ashish Singhal <ashishsingha@nvidia.com>
Tested-by: Ashish Singhal <ashishsingha@nvidia.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
---
 .../Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 40 ++++++++++++++++---
 1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
index d78918cf7b..0680ba36d9 100644
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
@@ -162,6 +162,36 @@ FreePageTablesRecursive (
   FreePages (TranslationTable, 1);
 }
 
+STATIC
+BOOLEAN
+IsBlockEntry (
+  IN  UINT64  Entry,
+  IN  UINTN   Level
+  )
+{
+  if (Level == 3) {
+    return (Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY_LEVEL3;
+  }
+  return (Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY;
+}
+
+STATIC
+BOOLEAN
+IsTableEntry (
+  IN  UINT64  Entry,
+  IN  UINTN   Level
+  )
+{
+  if (Level == 3) {
+    //
+    // TT_TYPE_TABLE_ENTRY aliases TT_TYPE_BLOCK_ENTRY_LEVEL3
+    // so we need to take the level into account as well.
+    //
+    return FALSE;
+  }
+  return (Entry & TT_TYPE_MASK) == TT_TYPE_TABLE_ENTRY;
+}
+
 STATIC
 EFI_STATUS
 UpdateRegionMappingRecursive (
@@ -203,7 +233,7 @@ UpdateRegionMappingRecursive (
     if (Level == 0 || ((RegionStart | BlockEnd) & BlockMask) != 0) {
       ASSERT (Level < 3);
 
-      if ((*Entry & TT_TYPE_MASK) != TT_TYPE_TABLE_ENTRY) {
+      if (!IsTableEntry (*Entry, Level)) {
         //
         // No table entry exists yet, so we need to allocate a page table
         // for the next level.
@@ -221,7 +251,7 @@ UpdateRegionMappingRecursive (
           InvalidateDataCacheRange (TranslationTable, EFI_PAGE_SIZE);
         }
 
-        if ((*Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY) {
+        if (IsBlockEntry (*Entry, Level)) {
           //
           // We are splitting an existing block entry, so we have to populate
           // the new table with the attributes of the block entry it replaces.
@@ -252,7 +282,7 @@ UpdateRegionMappingRecursive (
                  AttributeSetMask, AttributeClearMask, TranslationTable,
                  Level + 1);
       if (EFI_ERROR (Status)) {
-        if ((*Entry & TT_TYPE_MASK) != TT_TYPE_TABLE_ENTRY) {
+        if (!IsTableEntry (*Entry, Level)) {
           //
           // We are creating a new table entry, so on failure, we can free all
           // allocations we made recursively, given that the whole subhierarchy
@@ -265,10 +295,10 @@ UpdateRegionMappingRecursive (
         return Status;
       }
 
-      if ((*Entry & TT_TYPE_MASK) != TT_TYPE_TABLE_ENTRY) {
+      if (!IsTableEntry (*Entry, Level)) {
         EntryValue = (UINTN)TranslationTable | TT_TYPE_TABLE_ENTRY;
         ReplaceTableEntry (Entry, EntryValue, RegionStart,
-                           (*Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY);
+          IsBlockEntry (*Entry, Level));
       }
     } else {
       EntryValue = (*Entry & AttributeClearMask) | AttributeSetMask;