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authorli-elvin <li-elvin@6f19259b-4bc3-4df7-8a09-765794883524>2013-01-07 07:12:19 +0000
committerli-elvin <li-elvin@6f19259b-4bc3-4df7-8a09-765794883524>2013-01-07 07:12:19 +0000
commit48c8b6a299918612436e84ab22b55be6b88a90a2 (patch)
tree43399051f0c890f272dc5a6316f86c95625c2e36 /MdePkg/Library/BaseLib/Ia32/Thunk16.asm
parenta7f87053e00ff8a24664b24f745702fa1ece2d80 (diff)
downloadedk2-platforms-48c8b6a299918612436e84ab22b55be6b88a90a2.tar.xz
Current Thunk16.asm implementation clears reserved bits, which does not follow IA32 SDM. Now the fix is to only clear PAE and PSE bit of CR4 for real mode.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14037 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'MdePkg/Library/BaseLib/Ia32/Thunk16.asm')
-rw-r--r--MdePkg/Library/BaseLib/Ia32/Thunk16.asm4
1 files changed, 2 insertions, 2 deletions
diff --git a/MdePkg/Library/BaseLib/Ia32/Thunk16.asm b/MdePkg/Library/BaseLib/Ia32/Thunk16.asm
index 6df0a4a46a..3e84aedf3d 100644
--- a/MdePkg/Library/BaseLib/Ia32/Thunk16.asm
+++ b/MdePkg/Library/BaseLib/Ia32/Thunk16.asm
@@ -3,7 +3,7 @@
;------------------------------------------------------------------------------
;
-; Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
; This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution. The full text of the license may be found at
@@ -237,7 +237,7 @@ InternalAsmThunk16 PROC USES ebp ebx esi edi ds es fs gs
and eax, 7ffffffeh ; clear PE, PG bits
mov ebp, cr4
mov [edx + (SavedCr4 - SavedCr0)], ebp
- and ebp, 300h ; clear all but PCE and OSFXSR bits
+ and ebp, NOT 30h ; clear PAE, PSE bits
push 10h
pop ecx ; ecx <- selector for data segments
lgdt fword ptr [edx + (_16Gdtr - SavedCr0)]