1/*-
2 * Copyright (c) 2003 Jake Burkholder.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/param.h>
31#include <sys/signal.h>
32#include <sys/ucontext.h>
33
34#include <machine/frame.h>
35#include <machine/tstate.h>
36
37#include <errno.h>
38#include <stdarg.h>
39#include <stdlib.h>
40#include <unistd.h>
41
42__weak_reference(__makecontext, makecontext);
43
44void _ctx_done(ucontext_t *ucp);
45void _ctx_start(void);
46
47void
48__makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...)
49{
50	mcontext_t *mc;
51	uint64_t sp;
52	va_list ap;
53	int i;
54
55	mc = &ucp->uc_mcontext;
56	if (ucp == NULL ||
57	    (mc->_mc_flags & ((1L << _MC_VERSION_BITS) - 1)) != _MC_VERSION)
58		return;
59	if ((argc < 0) || (argc > 6) ||
60	    (ucp->uc_stack.ss_sp == NULL) ||
61	    (ucp->uc_stack.ss_size < MINSIGSTKSZ)) {
62		mc->_mc_flags = 0;
63		return;
64	}
65	mc = &ucp->uc_mcontext;
66	sp = (uint64_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size;
67	va_start(ap, argc);
68	for (i = 0; i < argc; i++)
69		mc->mc_out[i] = va_arg(ap, uint64_t);
70	va_end(ap);
71	mc->mc_global[1] = (uint64_t)start;
72	mc->mc_global[2] = (uint64_t)ucp;
73	mc->mc_out[6] = sp - SPOFF - sizeof(struct frame);
74	mc->_mc_tnpc = (uint64_t)_ctx_start + 4;
75	mc->_mc_tpc = (uint64_t)_ctx_start;
76}
77
78void
79_ctx_done(ucontext_t *ucp)
80{
81
82	if (ucp->uc_link == NULL)
83		exit(0);
84	else {
85		ucp->uc_mcontext._mc_flags = 0;
86		setcontext((const ucontext_t *)ucp->uc_link);
87		abort();
88	}
89}
90