1 /* Copyright (C) 1996-2019 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Andreas Schwab (schwab@issan.informatik.uni-dortmund.de)
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.
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.
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 <http://www.gnu.org/licenses/>. */
19 /* clone() is even more special than fork() as it mucks with stacks
20 and invokes a function in the right context after its all over. */
24 #include <bits/errno.h>
27 /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
28 void *parent_tidptr, void *tls, void *child_tidptr) */
33 /* Sanity check arguments. */
35 movel 4(%sp), %a0 /* no NULL function pointers */
37 jeq SYSCALL_ERROR_LABEL
38 movel 8(%sp), %a1 /* no NULL stack pointers */
40 jeq SYSCALL_ERROR_LABEL
42 /* Allocate space and copy the argument onto the new stack. */
45 /* Do the system call */
46 movel 12+0(%sp), %d1 /* get flags */
47 movel %d3, -(%a1) /* save %d3 and get parent_tidptr */
49 cfi_adjust_cfa_offset (4)
50 cfi_rel_offset (%d3, 0)
52 movel %d4, -(%a1) /* save %d4 and get child_tidptr */
54 cfi_adjust_cfa_offset (4)
55 cfi_rel_offset (%d4, 0)
57 movel %d5, -(%a1) /* save %d5 and get tls */
59 cfi_adjust_cfa_offset (4)
60 cfi_rel_offset (%d5, 0)
62 /* save %d2 and get stack pointer */
66 cfi_adjust_cfa_offset (4)
67 cfi_rel_offset (%d2, 0)
70 exg %d2, %a1 /* save %d2 and get stack pointer */
71 cfi_register (%d2, %a1)
73 movel #SYS_ify (clone), %d0
75 /* End FDE now, because in the child the unwind info will be
83 exg %d2, %a1 /* restore %d2 */
85 movel (%sp)+, %d5 /* restore %d5, %d4 and %d3 */
90 jmi SYSCALL_ERROR_LABEL
97 cfi_undefined (pc) /* Mark end of stack */
98 subl %fp, %fp /* terminate the stack frame */
101 movel #SYS_ify (exit), %d0
108 libc_hidden_def (__clone)
109 weak_alias (__clone, clone)