1/* $OpenBSD: tfork_thread.S,v 1.5 2023/12/10 16:45:52 deraadt Exp $ */
2
3/*
4 * Copyright (c) 2005 Tim Wiess <tim@nop.cx>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include "SYS.h"
20
21ENTRY(__tfork_thread)
22	RETGUARD_SETUP(__tfork_thread, %r11)
23
24	li	%r0, SYS___tfork
2599:	sc
26	PINSYSCALL(SYS___tfork, 99b)
27	cmpwi	%r0, 0
28	bne	1f
29
30	/* check if we are parent or child */
31	cmpwi	%r3, 0
32	bnelr
33
34	/* child */
35	mr	%r12, %r5
36	mtlr	%r5		/* fp */
37	mr	%r3, %r6	/* arg */
38	subi	%r1, %r1, 32	/* fixup sp to get headroom */
39	blrl
40
41	/* child returned, call __threxit */
42	li	%r0, SYS___threxit
4398:	sc
44	PINSYSCALL(SYS___threxit, 98b)
45	.long	0		/* illegal */
461:
47	stw	%r0, R13_OFFSET_ERRNO(%r13)
48	li	%r3, -1
49	RETGUARD_CHECK(__tfork_thread, %r11)
50	blr
51END(__tfork_thread)
52