From aa592e479db328a8703ca8d2eb790ed0051fdbb5 Mon Sep 17 00:00:00 2001
From: Olivier Martin <olivier.martin@arm.com>
Date: Mon, 6 Oct 2014 17:18:53 +0100
Subject: ArmPkg/ArmLib/AArch64: Initialize the new N+1-level page table before
 registering it

Prior to this change, when a new page table was created at level N+1,
the reference to the table was added to the level N translation table,
before being initialized.
It means if virtual addresses were in the address range defined by
this new table the CPU would crash as the address range was not
initialized.

Change-Id: Iff02afe0dfd7d296bac803bc07deef8552ed392f
---
 ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c b/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
index f0d2bff1a3..f215fe9275 100644
--- a/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
+++ b/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
@@ -251,6 +251,7 @@ GetBlockEntryListFromAddress (
   UINTN   RootTableEntryCount;
   UINT64 *TranslationTable;
   UINT64 *BlockEntry;
+  UINT64 *SubTableBlockEntry;
   UINT64  BlockEntryAddress;
   UINTN   BaseAddressAlignment;
   UINTN   PageLevel;
@@ -382,17 +383,18 @@ GetBlockEntryListFromAddress (
         }
         TranslationTable = (UINT64*)((UINTN)TranslationTable & TT_ADDRESS_MASK_DESCRIPTION_TABLE);
 
+        // Populate the newly created lower level table
+        SubTableBlockEntry = TranslationTable;
+        for (Index = 0; Index < TT_ENTRY_COUNT; Index++) {
+          *SubTableBlockEntry = Attributes | (BlockEntryAddress + (Index << TT_ADDRESS_OFFSET_AT_LEVEL(IndexLevel + 1)));
+          SubTableBlockEntry++;
+        }
+
         // Fill the BlockEntry with the new TranslationTable
         *BlockEntry = ((UINTN)TranslationTable & TT_ADDRESS_MASK_DESCRIPTION_TABLE) | TableAttributes | TT_TYPE_TABLE_ENTRY;
         // Update the last block entry with the newly created translation table
         *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(TranslationTable, TT_ENTRY_COUNT);
 
-        // Populate the newly created lower level table
-        BlockEntry = TranslationTable;
-        for (Index = 0; Index < TT_ENTRY_COUNT; Index++) {
-          *BlockEntry = Attributes | (BlockEntryAddress + (Index << TT_ADDRESS_OFFSET_AT_LEVEL(IndexLevel + 1)));
-          BlockEntry++;
-        }
         // Block Entry points at the beginning of the Translation Table
         BlockEntry = TranslationTable;
       }
-- 
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