xref: /openbsd/lib/libc/arch/aarch64/sys/tfork_thread.S (revision 274d7c50)
1/* $OpenBSD: tfork_thread.S,v 1.3 2018/08/12 17:15:10 mortimer Exp $ */
2/*
3 * Copyright (c) 2005 Dale Rahn <drahn@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17#include <sys/syscall.h>
18#include <machine/asm.h>
19#include "SYS.h"
20
21/*
22 *                r0     r1     r2         r3
23 * __tfork_thread(param, psize, start_fnc, start_arg);
24 */
25
26ENTRY(__tfork_thread)
27	RETGUARD_SETUP(__tfork_thread, x15)
28	SYSTRAP(__tfork)
29	bcs	CERROR
30
31	/* check if we are parent or child */
32	cbz	x0, 1f
33	RETGUARD_CHECK(__tfork_thread, x15)
34	ret
35
361:
37	/* child */
38	mov	x0, x3
39	blr	x2
40	SYSTRAP(__threxit)
41END(__tfork_thread)
42