From ad8cbf7197f41cbca4ac101d58f72dcf05c13860 Mon Sep 17 00:00:00 2001
From: rsun3 <rsun3@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Mon, 16 May 2011 06:10:42 +0000
Subject: [PATCH] Clear the direction flag in interrupt/exception handlers'
 assembly entry code before calling C functions to follow the UEFI calling
 convention.

Signed-off-by: rsun3
Reviewed-by:  jyao1


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11664 6f19259b-4bc3-4df7-8a09-765794883524
---
 MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm | 5 ++++-
 MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm  | 5 ++++-
 UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm                        | 5 ++++-
 UefiCpuPkg/CpuDxe/X64/CpuAsm.asm                         | 5 ++++-
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm b/MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm
index 80ee1824d6..32cbc31654 100644
--- a/MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm
+++ b/MdeModulePkg/Universal/DebugSupportDxe/Ia32/AsmFuncs.asm
@@ -1,7 +1,7 @@
 ;/** @file
 ;  Low leve IA32 specific debug support functions.
 ;
-;  Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
+;  Copyright (c) 2006 - 2011, 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
@@ -363,6 +363,9 @@ CommonIdtEntry::
                 ; They MUST be.  If they are not, a GP fault will occur.
                 FXSTOR_EDI
 
+;; UEFI calling convention for IA32 requires that Direction flag in EFLAGs is clear
+                cld
+
 ;; UINT32  ExceptionData;
                 mov     eax, ExceptData
                 push    eax
diff --git a/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm b/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm
index b9c32dd277..bce49ef762 100644
--- a/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm
+++ b/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.asm
@@ -1,7 +1,7 @@
 ;/** @file
 ;  Low level x64 routines used by the debug support driver.
 ;
-;  Copyright (c) 2007 - 2010, Intel Corporation. All rights reserved.<BR>
+;  Copyright (c) 2007 - 2011, 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
@@ -393,6 +393,9 @@ ExtraPushDone:
                 ; They MUST be.  If they are not, a GP fault will occur.
                 FXSTOR_RDI
 
+;; UEFI calling convention for x64 requires that Direction flag in EFLAGs is clear
+                cld
+
 ;; UINT64  ExceptionData;
                 mov     rax, ExceptData
                 push    rax
diff --git a/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm b/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm
index 68454bdeca..a279e6ab5a 100644
--- a/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm
+++ b/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm
@@ -1,7 +1,7 @@
       TITLE   CpuAsm.asm:
 ;------------------------------------------------------------------------------
 ;*
-;*   Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
+;*   Copyright (c) 2006 - 2011, 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
@@ -272,6 +272,9 @@ ErrorCodeAndVectorOnStack:
     mov     edi, esp
     db      0fh, 0aeh, 07h ;fxsave [edi]
 
+;; UEFI calling convention for IA32 requires that Direction flag in EFLAGs is clear
+    cld
+
 ;; UINT32  ExceptionData;
     push    dword ptr [ebp + 2 * 4]
 
diff --git a/UefiCpuPkg/CpuDxe/X64/CpuAsm.asm b/UefiCpuPkg/CpuDxe/X64/CpuAsm.asm
index 79edb7b83e..68fcd3f404 100644
--- a/UefiCpuPkg/CpuDxe/X64/CpuAsm.asm
+++ b/UefiCpuPkg/CpuDxe/X64/CpuAsm.asm
@@ -1,7 +1,7 @@
       TITLE   CpuAsm.asm: 
 ;------------------------------------------------------------------------------
 ;*
-;*   Copyright (c) 2008 - 2010, Intel Corporation. All rights reserved.<BR>
+;*   Copyright (c) 2008 - 2011, 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        
@@ -223,6 +223,9 @@ NoErrorCode:
     mov rdi, rsp
     db 0fh, 0aeh, 07h ;fxsave [rdi]
 
+;; UEFI calling convention for x64 requires that Direction flag in EFLAGs is clear
+    cld
+
 ;; UINT32  ExceptionData;
     push    qword ptr [rbp + 16]
 
-- 
2.39.2