1//===-- hwasan_setjmp_x86_64.S --------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// setjmp interceptor for x86_64.
10//
11//===----------------------------------------------------------------------===//
12
13#include "sanitizer_common/sanitizer_asm.h"
14
15#if HWASAN_WITH_INTERCEPTORS && defined(__x86_64__)
16#include "sanitizer_common/sanitizer_platform.h"
17
18// We want to save the context of the calling function.
19// That requires
20// 1) No modification of the return address by this function.
21// 2) No modification of the stack pointer by this function.
22// 3) (no modification of any other saved register, but that's not really going
23// to occur, and hence isn't as much of a worry).
24//
25// There's essentially no way to ensure that the compiler will not modify the
26// stack pointer when compiling a C function.
27// Hence we have to write this function in assembly.
28//
29// TODO: Handle Intel CET.
30
31.section .text
32.file "hwasan_setjmp_x86_64.S"
33
34.global __interceptor_setjmp
35ASM_TYPE_FUNCTION(__interceptor_setjmp)
36__interceptor_setjmp:
37  CFI_STARTPROC
38  _CET_ENDBR
39  xorl %esi, %esi
40  jmp	__interceptor_sigsetjmp
41  CFI_ENDPROC
42ASM_SIZE(__interceptor_setjmp)
43
44.global __interceptor_sigsetjmp
45ASM_TYPE_FUNCTION(__interceptor_sigsetjmp)
46__interceptor_sigsetjmp:
47  CFI_STARTPROC
48  _CET_ENDBR
49
50  // Save callee save registers.
51  mov %rbx, (0*8)(%rdi)
52  mov %rbp, (1*8)(%rdi)
53  mov %r12, (2*8)(%rdi)
54  mov %r13, (3*8)(%rdi)
55  mov %r14, (4*8)(%rdi)
56  mov %r15, (5*8)(%rdi)
57
58  // Save SP as it was in caller's frame.
59  lea 8(%rsp), %rdx
60  mov %rdx, (6*8)(%rdi)
61
62  // Save return address.
63  mov (%rsp), %rax
64  mov %rax, (7*8)(%rdi)
65
66  jmp __sigjmp_save
67
68  CFI_ENDPROC
69ASM_SIZE(__interceptor_sigsetjmp)
70
71
72.macro WEAK_ALIAS first second
73  .weak \second
74  .equ \second\(), \first
75.endm
76
77WEAK_ALIAS __interceptor_sigsetjmp, __sigsetjmp
78WEAK_ALIAS __interceptor_setjmp, _setjmp
79#endif
80
81// We do not need executable stack.
82NO_EXEC_STACK_DIRECTIVE
83