From: rsun3 <rsun3@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Fri, 11 Jun 2010 03:22:15 +0000 (+0000)
Subject: Skip restoration of DRx registers to support in-circuit emualators or debuggers set... 
X-Git-Tag: edk2-stable201903~15771
X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=61ece967cb59509608aa747fc9424c619646fc9d

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
---

diff --git a/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.S b/UefiCpuPkg/CpuDxe/Ia32/CpuAsm.S
index 04896578f7..d3e1dee624 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 f54fb291c0..68454bdeca 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
diff --git a/UefiCpuPkg/CpuDxe/X64/CpuAsm.S b/UefiCpuPkg/CpuDxe/X64/CpuAsm.S
index d6327325bf..8f191320a8 100644
--- a/UefiCpuPkg/CpuDxe/X64/CpuAsm.S
+++ b/UefiCpuPkg/CpuDxe/X64/CpuAsm.S
@@ -2,7 +2,7 @@
 
 #------------------------------------------------------------------------------
 #*
-#*   Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>
+#*   Copyright (c) 2008 - 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
@@ -218,16 +218,8 @@ CommonInterruptEntry_al_0000:
 #; UINT64  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
     movq    %dr7, %rax
     pushq   %rax
-#; clear Dr7 while executing debugger itself
-    xorq    %rax, %rax
-    movq    %rax, %dr7
-
     movq    %dr6, %rax
     pushq   %rax
-#; insure all status bits in dr6 are clear...
-    xorq    %rax, %rax
-    movq    %rax, %dr6
-
     movq    %dr3, %rax
     pushq   %rax
     movq    %dr2, %rax
@@ -277,18 +269,9 @@ nonNullValue:
     addq    $512, %rsp
 
 #; UINT64  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
-    popq    %rax
-    movq    %rax, %dr0
-    popq    %rax
-    movq    %rax, %dr1
-    popq    %rax
-    movq    %rax, %dr2
-    popq    %rax
-    movq    %rax, %dr3
-#; skip restore of dr6.  We cleared dr6 during the context save.
-    addq    $8, %rsp
-    popq    %rax
-    movq    %rax, %dr7
+#; Skip restoration of DRx registers to support in-circuit emualators
+#; or debuggers set breakpoint in interrupt/exception context
+    addq    $48, %rsp
 
 #; UINT64  Cr0, Cr1, Cr2, Cr3, Cr4, Cr8;
     popq    %rax
diff --git a/UefiCpuPkg/CpuDxe/X64/CpuAsm.asm b/UefiCpuPkg/CpuDxe/X64/CpuAsm.asm
index f8c650fae8..79edb7b83e 100644
--- a/UefiCpuPkg/CpuDxe/X64/CpuAsm.asm
+++ b/UefiCpuPkg/CpuDxe/X64/CpuAsm.asm
@@ -1,7 +1,7 @@
       TITLE   CpuAsm.asm: 
 ;------------------------------------------------------------------------------
 ;*
-;*   Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>
+;*   Copyright (c) 2008 - 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        
@@ -207,16 +207,8 @@ NoErrorCode:
 ;; UINT64  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
     mov     rax, dr7
     push    rax
-;; clear Dr7 while executing debugger itself
-    xor     rax, rax
-    mov     dr7, rax
-
     mov     rax, dr6
     push    rax
-;; insure all status bits in dr6 are clear...
-    xor     rax, rax
-    mov     dr6, rax
-
     mov     rax, dr3
     push    rax
     mov     rax, dr2
@@ -265,18 +257,9 @@ nonNullValue:
     add rsp, 512
 
 ;; UINT64  Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
-    pop     rax
-    mov     dr0, rax
-    pop     rax
-    mov     dr1, rax
-    pop     rax
-    mov     dr2, rax
-    pop     rax
-    mov     dr3, rax
-;; skip restore of dr6.  We cleared dr6 during the context save.
-    add     rsp, 8
-    pop     rax
-    mov     dr7, rax
+;; Skip restoration of DRx registers to support in-circuit emualators
+;; or debuggers set breakpoint in interrupt/exception context
+    add     rsp, 8 * 6
 
 ;; UINT64  Cr0, Cr1, Cr2, Cr3, Cr4, Cr8;
     pop     rax