1/*-
2 * Copyright (c) 2015 The FreeBSD Foundation
3 *
4 * This software was developed by Andrew Turner under
5 * sponsorship from the FreeBSD Foundation.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/param.h>
30
31#include <machine/armreg.h>
32
33#include <inttypes.h>
34#include <stdarg.h>
35#include <stdlib.h>
36#include <ucontext.h>
37
38void _ctx_start(void);
39
40void
41ctx_done(ucontext_t *ucp)
42{
43
44	if (ucp->uc_link == NULL) {
45		exit(0);
46	} else {
47		setcontext((const ucontext_t *)ucp->uc_link);
48		abort();
49	}
50}
51
52__weak_reference(__makecontext, makecontext);
53
54void
55__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
56{
57	struct gpregs *gp;
58	va_list ap;
59	int i;
60
61	/* A valid context is required. */
62	if (ucp == NULL)
63		return;
64
65	if ((argc < 0) || (argc > 8))
66		return;
67
68	gp = &ucp->uc_mcontext.mc_gpregs;
69
70	va_start(ap, argc);
71	/* Pass up to eight arguments in x0-7. */
72	for (i = 0; i < argc && i < 8; i++)
73		gp->gp_x[i] = va_arg(ap, uint64_t);
74	va_end(ap);
75
76	/* Set the stack */
77	gp->gp_sp = STACKALIGN(ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
78	/* Arrange for return via the trampoline code. */
79	gp->gp_elr = (__register_t)_ctx_start;
80	gp->gp_x[19] = (__register_t)func;
81	gp->gp_x[20] = (__register_t)ucp;
82}
83