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f493cf81 JJ |
1 | ;------------------------------------------------------------------------------\r |
2 | ;\r | |
d3febfd9 | 3 | ; Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>\r |
9344f092 | 4 | ; SPDX-License-Identifier: BSD-2-Clause-Patent\r |
f493cf81 JJ |
5 | ;\r |
6 | ; Module Name:\r | |
7 | ;\r | |
8 | ; LongJump.Asm\r | |
9 | ;\r | |
10 | ; Abstract:\r | |
11 | ;\r | |
12 | ; Implementation of _LongJump() on IA-32.\r | |
13 | ;\r | |
14 | ;------------------------------------------------------------------------------\r | |
15 | \r | |
0aac2f77 JY |
16 | %include "Nasm.inc"\r |
17 | \r | |
f493cf81 JJ |
18 | SECTION .text\r |
19 | \r | |
0aac2f77 JY |
20 | extern ASM_PFX(PcdGet32 (PcdControlFlowEnforcementPropertyMask))\r |
21 | \r | |
f493cf81 JJ |
22 | ;------------------------------------------------------------------------------\r |
23 | ; VOID\r | |
24 | ; EFIAPI\r | |
25 | ; InternalLongJump (\r | |
26 | ; IN BASE_LIBRARY_JUMP_BUFFER *JumpBuffer,\r | |
27 | ; IN UINTN Value\r | |
28 | ; );\r | |
29 | ;------------------------------------------------------------------------------\r | |
30 | global ASM_PFX(InternalLongJump)\r | |
31 | ASM_PFX(InternalLongJump):\r | |
0aac2f77 JY |
32 | \r |
33 | mov eax, [ASM_PFX(PcdGet32 (PcdControlFlowEnforcementPropertyMask))]\r | |
34 | test eax, eax\r | |
35 | jz CetDone\r | |
36 | mov eax, cr4\r | |
37 | bt eax, 23 ; check if CET is enabled\r | |
38 | jnc CetDone\r | |
39 | \r | |
40 | mov edx, [esp + 4] ; edx = JumpBuffer\r | |
41 | mov edx, [edx + 24] ; edx = target SSP\r | |
d3febfd9 | 42 | rdsspd eax\r |
0aac2f77 JY |
43 | sub edx, eax ; edx = delta\r |
44 | mov eax, edx ; eax = delta\r | |
45 | \r | |
46 | shr eax, 2 ; eax = delta/sizeof(UINT32)\r | |
d3febfd9 | 47 | incsspd eax\r |
0aac2f77 JY |
48 | \r |
49 | CetDone:\r | |
50 | \r | |
f493cf81 JJ |
51 | pop eax ; skip return address\r |
52 | pop edx ; edx <- JumpBuffer\r | |
53 | pop eax ; eax <- Value\r | |
54 | mov ebx, [edx]\r | |
55 | mov esi, [edx + 4]\r | |
56 | mov edi, [edx + 8]\r | |
57 | mov ebp, [edx + 12]\r | |
58 | mov esp, [edx + 16]\r | |
59 | jmp dword [edx + 20] ; restore "eip"\r | |
60 | \r |