xref: /openbsd-src/lib/libc/arch/aarch64/sys/tfork_thread.S (revision ff25319c393a2dcaf4b059c8970d8b604c7605a1)
1/* $OpenBSD: tfork_thread.S,v 1.8 2022/12/24 10:47:22 kettenis 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
18#include "SYS.h"
19
20/*
21 *                r0     r1     r2         r3
22 * __tfork_thread(param, psize, start_fnc, start_arg);
23 */
24
25ENTRY(__tfork_thread)
26	.cfi_startproc
27	RETGUARD_SETUP(__tfork_thread, x15)
28	SYSTRAP(__tfork)
29	.cfi_endproc
30	bcs	CERROR
31
32	/* check if we are parent or child */
33	cbz	x0, 1f
34	RETGUARD_CHECK(__tfork_thread, x15)
35	ret
36
371:
38	.cfi_startproc
39	.cfi_undefined	lr
40	/* child */
41	mov	fp, #0
42	mov	x0, x3
43	blr	x2
44	SYSTRAP(__threxit)
45	udf	#0
46	.cfi_endproc
47END(__tfork_thread)
48