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 ASM_WRAPPER_NAME(setjmp)
35ASM_TYPE_FUNCTION(ASM_WRAPPER_NAME(setjmp))
36ASM_WRAPPER_NAME(setjmp):
37 CFI_STARTPROC
38 _CET_ENDBR
39 xorl %esi, %esi
40 jmp .Linterceptor_sigsetjmp
41 CFI_ENDPROC
42ASM_SIZE(ASM_WRAPPER_NAME(setjmp))
43
44.global ASM_WRAPPER_NAME(sigsetjmp)
45ASM_TYPE_FUNCTION(ASM_WRAPPER_NAME(sigsetjmp))
46ASM_WRAPPER_NAME(sigsetjmp):
47.Linterceptor_sigsetjmp:
48 CFI_STARTPROC
49 _CET_ENDBR
50
51 // Save callee save registers.
52 mov %rbx, (0*8)(%rdi)
53 mov %rbp, (1*8)(%rdi)
54 mov %r12, (2*8)(%rdi)
55 mov %r13, (3*8)(%rdi)
56 mov %r14, (4*8)(%rdi)
57 mov %r15, (5*8)(%rdi)
58
59 // Save SP as it was in caller's frame.
60 lea 8(%rsp), %rdx
61 mov %rdx, (6*8)(%rdi)
62
63 // Save return address.
64 mov (%rsp), %rax
65 mov %rax, (7*8)(%rdi)
66
67 jmp __sigjmp_save
68
69 CFI_ENDPROC
70ASM_SIZE(ASM_WRAPPER_NAME(sigsetjmp))
71
72ASM_INTERCEPTOR_TRAMPOLINE(sigsetjmp)
73ASM_TRAMPOLINE_ALIAS(__sigsetjmp, sigsetjmp)
74ASM_INTERCEPTOR_TRAMPOLINE(setjmp)
75ASM_TRAMPOLINE_ALIAS(_setjmp, setjmp)
76#endif
77
78// We do not need executable stack.
79NO_EXEC_STACK_DIRECTIVE
80