1/* Wrapper around clone system call.  64 bit S/390 version.
2   Copyright (C) 2001-2022 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/* 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.  */
21
22#include <sysdep.h>
23#include <tls.h>
24#define _ERRNO_H	1
25#include <bits/errno.h>
26
27/* int __clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
28               pid_t *parent_tid, void *tls, pid_t *child_tid);  */
29/* sys_clone  (void *child_stack, unsigned long flags,
30               pid_t *parent_tid, pid_t *child_tid, void *tls);  */
31
32	.text
33ENTRY(__clone)
34	stg	%r6,48(%r15)		/* store %r6 to save area */
35	cfi_offset (%r6,-112)
36	ltgr    %r1,%r2			/* check fn and move to %r1 */
37	jz      error			/* no NULL function pointers */
38	lghi	%r0,-16			/* Align the child_stack to a ...  */
39	ngr	%r3,%r0			/* double word boundary and ...  */
40	jz	error			/* avoid NULL stack pointers.  */
41	lgr	%r0,%r5			/* move *arg out of the way */
42	lgr	%r2,%r3			/* move child_stack to %r2  */
43	lgr	%r3,%r4			/* move flags to %r3 */
44	lgr	%r4,%r6			/* move parent_tid to %r4 */
45	lg	%r5,168(%r15)		/* load child_tid from stack */
46	lg	%r6,160(%r15)		/* load tls from stack */
47	svc	SYS_ify(clone)
48	ltgr	%r2,%r2			/* check return code */
49	jz	thread_start
50	lg	%r6,48(%r15)		/* restore %r6 */
51	jgm	SYSCALL_ERROR_LABEL
52	br	%r14
53error:
54	lghi	%r2,-EINVAL
55	jg	SYSCALL_ERROR_LABEL
56PSEUDO_END (__clone)
57
58thread_start:
59	cfi_startproc
60	/* Mark r14 as undefined in order to stop unwinding here!  */
61	cfi_undefined (r14)
62	/* fn is in gpr 1, arg in gpr 0 */
63	lgr	%r2,%r0		/* set first parameter to void *arg */
64	aghi	%r15,-160	/* make room on the stack for the save area */
65	xc	0(8,%r15),0(%r15)
66	basr	%r14,%r1	/* jump to fn */
67	DO_CALL	(exit, 1)
68	cfi_endproc
69
70libc_hidden_def (__clone)
71weak_alias (__clone, clone)
72