1 files changed, 82 insertions, 0 deletions
diff --git a/IntelFspPkg/FspSecCore/Ia32/Stack.asm b/IntelFspPkg/FspSecCore/Ia32/Stack.asm
new file mode 100644
index 0000000000..f96a55f040
--- /dev/null
+++ b/IntelFspPkg/FspSecCore/Ia32/Stack.asm
@@ -0,0 +1,82 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2014, 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
+; http://opensource.org/licenses/bsd-license.php.
+;
+; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+;
+; Abstract:
+;
+;   Switch the stack from temporary memory to permenent memory.
+;
+;------------------------------------------------------------------------------
+
+    .586p
+    .model  flat,C
+    .code
+
+;------------------------------------------------------------------------------
+; VOID
+; EFIAPI
+; SecSwitchStack (
+;   UINT32   TemporaryMemoryBase,
+;   UINT32   PermenentMemoryBase
+;   );
+;------------------------------------------------------------------------------
+SecSwitchStack   PROC
+    ;
+    ; Save three register: eax, ebx, ecx
+    ;
+    push  eax
+    push  ebx
+    push  ecx
+    push  edx
+
+    ;
+    ; !!CAUTION!! this function address's is pushed into stack after
+    ; migration of whole temporary memory, so need save it to permenent
+    ; memory at first!
+    ;
+
+    mov   ebx, [esp + 20]          ; Save the first parameter
+    mov   ecx, [esp + 24]          ; Save the second parameter
+
+    ;
+    ; Save this function's return address into permenent memory at first.
+    ; Then, Fixup the esp point to permenent memory
+    ;
+    mov   eax, esp
+    sub   eax, ebx
+    add   eax, ecx
+    mov   edx, dword ptr [esp]         ; copy pushed register's value to permenent memory
+    mov   dword ptr [eax], edx
+    mov   edx, dword ptr [esp + 4]
+    mov   dword ptr [eax + 4], edx
+    mov   edx, dword ptr [esp + 8]
+    mov   dword ptr [eax + 8], edx
+    mov   edx, dword ptr [esp + 12]
+    mov   dword ptr [eax + 12], edx
+    mov   edx, dword ptr [esp + 16]    ; Update this function's return address into permenent memory
+    mov   dword ptr [eax + 16], edx
+    mov   esp, eax                     ; From now, esp is pointed to permenent memory
+
+    ;
+    ; Fixup the ebp point to permenent memory
+    ;
+    mov   eax, ebp
+    sub   eax, ebx
+    add   eax, ecx
+    mov   ebp, eax                ; From now, ebp is pointed to permenent memory
+
+    pop   edx
+    pop   ecx
+    pop   ebx
+    pop   eax
+    ret
+SecSwitchStack   ENDP
+
+    END