From: Heyi Guo <heyi.guo@linaro.org>
Date: Wed, 9 Sep 2015 13:37:22 +0000 (+0000)
Subject: ArmPkg/Mmu: Fix page level calculation bug
X-Git-Tag: edk2-stable201903~8895
X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=946067bfb074962667bd61fafffd0e777242e12b

ArmPkg/Mmu: Fix page level calculation bug

The bug can be triggered when alignment of Base is larger than Length
by 2 level of page granularity, e.g.

Base is 0x4000_0000, Length is 0x1000

The original code will change 2MB page level and we will get a
negative remaining length.

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

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18422 6f19259b-4bc3-4df7-8a09-765794883524
---

diff --git a/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c b/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
index a7f374531a..5b6c4537b5 100644
--- a/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
+++ b/ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c
@@ -314,7 +314,7 @@ GetBlockEntryListFromAddress (
   // If the required size is smaller than the current block size then we need to go to the page below.
   // The PageLevel was calculated on the Base Address alignment but did not take in account the alignment
   // of the allocation size
-  if (*BlockEntrySize < TT_BLOCK_ENTRY_SIZE_AT_LEVEL (PageLevel)) {
+  while (*BlockEntrySize < TT_BLOCK_ENTRY_SIZE_AT_LEVEL (PageLevel)) {
     // It does not fit so we need to go a page level above
     PageLevel++;
   }