Skip restoration of DRx registers to support in-circuit emualators or debuggers set breakpoint in interrupt/exception context.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10573 6f19259b-4bc3-4df7-8a09-765794883524

2 files changed, 8 insertions, 42 deletions

diff --git a/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.S b/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.S
index 0489657..d3e1dee 100644
--- a/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.S
+++ b/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.S
@@ -1,6 +1,6 @@
 #------------------------------------------------------------------------------

 #*

-#*   Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>

+#*   Copyright (c) 2006 - 2010, 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

@@ -258,16 +258,8 @@ ErrorCodeAndVectorOnStack:
 #; UINT32  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;

     movl    %dr7, %eax

     pushl   %eax

-#; clear Dr7 while executing debugger itself

-    xorl    %eax, %eax

-    movl    %eax, %dr7

-

     movl    %dr6, %eax

     pushl   %eax

-#; insure all status bits in dr6 are clear...

-    xorl    %eax, %eax

-    movl    %eax, %dr6

-

     movl    %dr3, %eax

     pushl   %eax

     movl    %dr2, %eax

@@ -319,18 +311,9 @@ nullExternalExceptionHandler:
     addl    $512, %esp

 

 #; UINT32  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;

-    popl    %eax

-    movl    %eax, %dr0

-    popl    %eax

-    movl    %eax, %dr1

-    popl    %eax

-    movl    %eax, %dr2

-    popl    %eax

-    movl    %eax, %dr3

-#; skip restore of dr6.  We cleared dr6 during the context save.

-    addl    $4, %esp

-    popl    %eax

-    movl    %eax, %dr7

+#; Skip restoration of DRx registers to support in-circuit emualators

+#; or debuggers set breakpoint in interrupt/exception context

+    addl    $24, %esp

 

 #; UINT32  Cr0, Cr1, Cr2, Cr3, Cr4;

     popl    %eax

diff --git a/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm b/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm
index f54fb29..68454bd 100644
--- a/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm
+++ b/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.asm
@@ -1,7 +1,7 @@
       TITLE   CpuAsm.asm:

 ;------------------------------------------------------------------------------

 ;*

-;*   Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>

+;*   Copyright (c) 2006 - 2010, 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

@@ -256,16 +256,8 @@ ErrorCodeAndVectorOnStack:
 ;; UINT32  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;

     mov     eax, dr7

     push    eax

-;; clear Dr7 while executing debugger itself

-    xor     eax, eax

-    mov     dr7, eax

-

     mov     eax, dr6

     push    eax

-;; insure all status bits in dr6 are clear...

-    xor     eax, eax

-    mov     dr6, eax

-

     mov     eax, dr3

     push    eax

     mov     eax, dr2

@@ -317,18 +309,9 @@ nullExternalExceptionHandler:
     add     esp, 512

 

 ;; UINT32  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;

-    pop     eax

-    mov     dr0, eax

-    pop     eax

-    mov     dr1, eax

-    pop     eax

-    mov     dr2, eax

-    pop     eax

-    mov     dr3, eax

-;; skip restore of dr6.  We cleared dr6 during the context save.

-    add     esp, 4

-    pop     eax

-    mov     dr7, eax

+;; Skip restoration of DRx registers to support in-circuit emualators

+;; or debuggers set breakpoint in interrupt/exception context

+    add     esp, 4 * 6

 

 ;; UINT32  Cr0, Cr1, Cr2, Cr3, Cr4;

     pop     eax