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;------------------------------------------------------------------------------
;
; Copyright (c) 2022, 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 PermanentMemoryBase
; );
;------------------------------------------------------------------------------
global ASM_PFX(SecSwitchStack)
ASM_PFX(SecSwitchStack):
;
; Save four register: rax, rbx, rcx, rdx
;
push rax
push rbx
push rcx
push rdx
;
; !!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 rbx, rcx ; Save the first parameter
mov rcx, rdx ; Save the second parameter
;
; Save this function's return address into permanent memory at first.
; Then, Fixup the esp point to permanent memory
;
mov rax, rsp
sub rax, rbx
add rax, rcx
mov rdx, qword [rsp] ; copy pushed register's value to permanent memory
mov qword [rax], rdx
mov rdx, qword [rsp + 8]
mov qword [rax + 8], rdx
mov rdx, qword [rsp + 16]
mov qword [rax + 16], rdx
mov rdx, qword [rsp + 24]
mov qword [rax + 24], rdx
mov rdx, qword [rsp + 32] ; Update this function's return address into permanent memory
mov qword [rax + 32], rdx
mov rsp, rax ; From now, rsp is pointed to permanent memory
;
; Fixup the rbp point to permanent memory
;
mov rax, rbp
sub rax, rbx
add rax, rcx
mov rbp, rax ; From now, rbp is pointed to permanent memory
pop rdx
pop rcx
pop rbx
pop rax
ret
|
