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