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;------------------------------------------------------------------------------
;
; Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Abstract:
;
; Switch the stack from temporary memory to permanent memory.
;
;------------------------------------------------------------------------------
SECTION .text
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; SecSwitchStack (
; UINT32 TemporaryMemoryBase,
; UINT32 PermenentMemoryBase
; );
;------------------------------------------------------------------------------
global ASM_PFX(SecSwitchStack)
ASM_PFX(SecSwitchStack):
;
; 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 permanent
; 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 permanent memory at first.
; Then, Fixup the esp point to permanent memory
;
mov eax, esp
sub eax, ebx
add eax, ecx
mov edx, dword [esp] ; copy pushed register's value to permanent memory
mov dword [eax], edx
mov edx, dword [esp + 4]
mov dword [eax + 4], edx
mov edx, dword [esp + 8]
mov dword [eax + 8], edx
mov edx, dword [esp + 12]
mov dword [eax + 12], edx
mov edx, dword [esp + 16] ; Update this function's return address into permanent memory
mov dword [eax + 16], edx
mov esp, eax ; From now, esp is pointed to permanent 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 permanent memory
pop edx
pop ecx
pop ebx
pop eax
ret
|
