xref: /openbsd/lib/libc/arch/aarch64/sys/tfork_thread.S (revision 55cc5ba3)
1/* $OpenBSD: tfork_thread.S,v 1.6 2020/10/19 17:57:40 naddy 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	.cfi_startproc
28	RETGUARD_SETUP(__tfork_thread, x15)
29	SYSTRAP(__tfork)
30	.cfi_endproc
31	bcs	CERROR
32
33	/* check if we are parent or child */
34	cbz	x0, 1f
35	RETGUARD_CHECK(__tfork_thread, x15)
36	ret
37
381:
39	.cfi_startproc
40	.cfi_undefined	lr
41	/* child */
42	ldr	fp, 0
43	mov	x0, x3
44	blr	x2
45	SYSTRAP(__threxit)
46	udf	#0
47	.cfi_endproc
48END(__tfork_thread)
49