;------------------------------------------------------------------------------ | |
; | |
; Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR> | |
; SPDX-License-Identifier: BSD-2-Clause-Patent | |
; | |
; Module Name: | |
; | |
; LongJump.Asm | |
; | |
; Abstract: | |
; | |
; Implementation of _LongJump() on IA-32. | |
; | |
;------------------------------------------------------------------------------ | |
%include "Nasm.inc" | |
SECTION .text | |
extern ASM_PFX(PcdGet32 (PcdControlFlowEnforcementPropertyMask)) | |
;------------------------------------------------------------------------------ | |
; VOID | |
; EFIAPI | |
; InternalLongJump ( | |
; IN BASE_LIBRARY_JUMP_BUFFER *JumpBuffer, | |
; IN UINTN Value | |
; ); | |
;------------------------------------------------------------------------------ | |
global ASM_PFX(InternalLongJump) | |
ASM_PFX(InternalLongJump): | |
mov eax, [ASM_PFX(PcdGet32 (PcdControlFlowEnforcementPropertyMask))] | |
test eax, eax | |
jz CetDone | |
mov eax, cr4 | |
bt eax, 23 ; check if CET is enabled | |
jnc CetDone | |
mov edx, [esp + 4] ; edx = JumpBuffer | |
mov edx, [edx + 24] ; edx = target SSP | |
rdsspd eax | |
sub edx, eax ; edx = delta | |
mov eax, edx ; eax = delta | |
shr eax, 2 ; eax = delta/sizeof(UINT32) | |
incsspd eax | |
CetDone: | |
pop eax ; skip return address | |
pop edx ; edx <- JumpBuffer | |
pop eax ; eax <- Value | |
mov ebx, [edx] | |
mov esi, [edx + 4] | |
mov edi, [edx + 8] | |
mov ebp, [edx + 12] | |
mov esp, [edx + 16] | |
jmp dword [edx + 20] ; restore "eip" | |