ArmPkg/Mmu: Fix potential page table memory leak

During page entry attribute update, if there are table entries
between starting BlockEntry and LastBlockEntry, table entries will be
set as block entries and the allocated memory of the tables will be
leaked.

So instead, we break the inner loop when we find a table entry and run
outer loop again to step into the table by the same logic.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>

[ardb: move termination condition check inside the loop]
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18425 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 7 insertions, 0 deletions

diff --git a/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c b/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
index 850fe7f..df37154 100644
--- a/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
+++ b/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
@@ -455,6 +455,13 @@ FillTranslationTable (
       RegionStart += BlockEntrySize;

       RemainingRegionLength -= BlockEntrySize;

       BlockEntry++;

+

+      // Break the inner loop when next block is a table

+      // Rerun GetBlockEntryListFromAddress to avoid page table memory leak

+      if (TableLevel != 3 &&

+          (*BlockEntry & TT_TYPE_MASK) == TT_TYPE_TABLE_ENTRY) {

+            break;

+      }

     } while ((RemainingRegionLength >= BlockEntrySize) && (BlockEntry <= LastBlockEntry));

   } while (RemainingRegionLength != 0);