1/* Copyright (C) 1999-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library. If not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <sysdep.h>
19#define _ERRNO_H 1
20#include <bits/errno.h>
21#include <tcb-offsets.h>
22
23
24/* Clone the calling process, but without copying the whole address space.
25 The calling process is suspended until the new process exits or is
26 replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
27 and the process ID of the new process to the old process. */
28
29ENTRY (__vfork)
30 /* The DO_CALL macro saves r7 on the stack, to enable generation
31 of ARM unwind info. Since the stack is initially shared between
32 parent and child of vfork, that saved value could be corrupted.
33 To avoid this problem, we save r7 into ip as well, and restore
34 from there. */
35 mov ip, r7
36 cfi_register (r7, ip)
37 .fnstart
38 push { r7 }
39 cfi_adjust_cfa_offset (4)
40 .save { r7 }
41 ldr r7, =SYS_ify (vfork)
42 swi 0x0
43 .fnend
44 add sp, sp, #4
45 cfi_adjust_cfa_offset (-4)
46 mov r7, ip
47 cfi_restore (r7)
48
49 cmn a1, #4096
50 it cc
51 RETINSTR(cc, lr)
52
53 b PLTJMP(SYSCALL_ERROR)
54PSEUDO_END (__vfork)
55libc_hidden_def (__vfork)
56
57weak_alias (__vfork, vfork)
58strong_alias (__vfork, __libc_vfork)
59

source code of glibc/sysdeps/unix/sysv/linux/arm/vfork.S