1/* BSD `setjmp' entry point to `sigsetjmp (..., 1)'. i386 version.
2 Copyright (C) 1994-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19/* This just does a tail-call to `__sigsetjmp (ARG, 1)'.
20 We cannot do it in C because it must be a tail-call, so frame-unwinding
21 in setjmp doesn't clobber the state restored by longjmp. */
22
23#include <sysdep.h>
24#include <pointer_guard.h>
25#include <jmpbuf-offsets.h>
26#include <stap-probe.h>
27
28#define PARMS 4 /* no space for saved regs */
29#define JMPBUF PARMS
30#define SIGMSK JMPBUF+4
31
32ENTRY (setjmp)
33 /* Note that we have to use a non-exported symbol in the next
34 jump since otherwise gas will emit it as a jump through the
35 PLT which is what we cannot use here. */
36
37 movl JMPBUF(%esp), %eax
38
39 /* Save registers. */
40 movl %ebx, (JB_BX*4)(%eax)
41 movl %esi, (JB_SI*4)(%eax)
42 movl %edi, (JB_DI*4)(%eax)
43 leal JMPBUF(%esp), %ecx /* Save SP as it will be after we return. */
44#ifdef PTR_MANGLE
45 PTR_MANGLE (%ecx)
46#endif
47 movl %ecx, (JB_SP*4)(%eax)
48 movl 0(%esp), %ecx /* Save PC we are returning to now. */
49 LIBC_PROBE (setjmp, 3, 4@%eax, -4@$1, 4@%ecx)
50#ifdef PTR_MANGLE
51 PTR_MANGLE (%ecx)
52#endif
53 movl %ecx, (JB_PC*4)(%eax)
54 movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
55
56 /* Call __sigjmp_save. */
57 pushl $1
58 cfi_adjust_cfa_offset (4)
59 pushl 8(%esp)
60 cfi_adjust_cfa_offset (4)
61 call __sigjmp_save
62 popl %ecx
63 cfi_adjust_cfa_offset (-4)
64 popl %edx
65 cfi_adjust_cfa_offset (-4)
66 ret
67END (setjmp)
68

source code of glibc/sysdeps/i386/bsd-setjmp.S