From 63d7211ebcfa7cb217a9e50143e1ac1a8119626a Mon Sep 17 00:00:00 2001
From: xli24 <xli24@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Tue, 13 Jan 2009 04:20:22 +0000
Subject: Fix the bug that EntryPoint of DisablePaging64() is corrupted.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@7250 6f19259b-4bc3-4df7-8a09-765794883524
---
 MdePkg/Library/BaseLib/X64/DisablePaging64.S   | 4 +++-
 MdePkg/Library/BaseLib/X64/DisablePaging64.asm | 6 ++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

(limited to 'MdePkg/Library')

diff --git a/MdePkg/Library/BaseLib/X64/DisablePaging64.S b/MdePkg/Library/BaseLib/X64/DisablePaging64.S
index a55059e3be..8c71d2d49e 100644
--- a/MdePkg/Library/BaseLib/X64/DisablePaging64.S
+++ b/MdePkg/Library/BaseLib/X64/DisablePaging64.S
@@ -51,6 +51,8 @@ L1:
     mov    %cr0,%rax
     btr    $0x1f,%eax
     mov    %rax,%cr0                      # disable paging
+
+    mov    %rdx,%rbx                      # save EntryPoint to rbx, for rdmsr will overwrite rdx
     mov    $0xc0000080,%ecx
     rdmsr  
     and    $0xfe,%ah                      # clear LME
@@ -60,6 +62,6 @@ L1:
     mov    %rax,%cr4
     push   %rdi                           # push Context2
     push   %rsi                           # push Context1
-    callq  *%rdx                          # transfer control to EntryPoint
+    callq  *%rbx                          # transfer control to EntryPoint
     jmp    .                              # no one should get here
 
diff --git a/MdePkg/Library/BaseLib/X64/DisablePaging64.asm b/MdePkg/Library/BaseLib/X64/DisablePaging64.asm
index 518137ddc9..29bf558e6c 100644
--- a/MdePkg/Library/BaseLib/X64/DisablePaging64.asm
+++ b/MdePkg/Library/BaseLib/X64/DisablePaging64.asm
@@ -1,6 +1,6 @@
 ;------------------------------------------------------------------------------
 ;
-; Copyright (c) 2006, Intel Corporation
+; Copyright (c) 2006 - 2008, Intel Corporation
 ; All rights reserved. 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
@@ -49,6 +49,8 @@ InternalX86DisablePaging64    PROC
     mov     rax, cr0
     btr     eax, 31
     mov     cr0, rax                    ; disable paging
+
+    mov     rbx, rdx                    ; save EntryPoint to rbx, for rdmsr will overwrite rdx
     mov     ecx, 0c0000080h
     rdmsr
     and     ah, NOT 1                   ; clear LME
@@ -58,7 +60,7 @@ InternalX86DisablePaging64    PROC
     mov     cr4, rax
     push    rdi                         ; push Context2
     push    rsi                         ; push Context1
-    call    rdx                         ; transfer control to EntryPoint
+    call    rbx                         ; transfer control to EntryPoint
     hlt                                 ; no one should get here
 InternalX86DisablePaging64    ENDP
 
-- 
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