xref: /openbsd/lib/libc/arch/riscv64/sys/tfork_thread.S (revision 73471bf0)
1/*	$OpenBSD: tfork_thread.S,v 1.2 2021/05/04 04:26:00 drahn Exp $	*/
2/*
3 * Copyright (c) 2020 Brian Bamsch <bbamsch@google.com>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the copyright holder nor the names of contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTOR(S) ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTOR(S) BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include "SYS.h"
32
33/*
34 *                a0     a1     a2         a3
35 * __tfork_thread(param, psize, start_fnc, start_arg);
36 */
37
38ENTRY(__tfork_thread)
39	RETGUARD_SETUP(__tfork_thread, t6)
40	SYSTRAP(__tfork)
41	HANDLE_ERROR_TARGET(2f)
42
43	beqz	a0, 1f
44	/* parent thread */
452:
46	RETGUARD_CHECK(__tfork_thread, t6)
47	ret
48
491:	/* child thread */
50	mv	a0, a3
51	jalr	a2
52	SYSTRAP(__threxit)
53END(__tfork_thread)
54