1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2003 Jake Burkholder.
5 * All rights reserved.
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/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/signal.h>
34 #include <sys/ucontext.h>
35
36 #include <machine/frame.h>
37 #include <machine/tstate.h>
38
39 #include <errno.h>
40 #include <stdarg.h>
41 #include <stdlib.h>
42 #include <unistd.h>
43
44 __weak_reference(__makecontext, makecontext);
45
46 void _ctx_done(ucontext_t *ucp);
47 void _ctx_start(void);
48
49 void
__makecontext(ucontext_t * ucp,void (* start)(void),int argc,...)50 __makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...)
51 {
52 mcontext_t *mc;
53 uint64_t sp;
54 va_list ap;
55 int i;
56
57 mc = &ucp->uc_mcontext;
58 if (ucp == NULL ||
59 (mc->_mc_flags & ((1L << _MC_VERSION_BITS) - 1)) != _MC_VERSION)
60 return;
61 if ((argc < 0) || (argc > 6) ||
62 (ucp->uc_stack.ss_sp == NULL) ||
63 (ucp->uc_stack.ss_size < MINSIGSTKSZ)) {
64 mc->_mc_flags = 0;
65 return;
66 }
67 mc = &ucp->uc_mcontext;
68 sp = (uint64_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size;
69 va_start(ap, argc);
70 for (i = 0; i < argc; i++)
71 mc->mc_out[i] = va_arg(ap, uint64_t);
72 va_end(ap);
73 mc->mc_global[1] = (uint64_t)start;
74 mc->mc_global[2] = (uint64_t)ucp;
75 mc->mc_out[6] = sp - SPOFF - sizeof(struct frame);
76 mc->_mc_tnpc = (uint64_t)_ctx_start + 4;
77 mc->_mc_tpc = (uint64_t)_ctx_start;
78 }
79
80 void
_ctx_done(ucontext_t * ucp)81 _ctx_done(ucontext_t *ucp)
82 {
83
84 if (ucp->uc_link == NULL)
85 exit(0);
86 else {
87 ucp->uc_mcontext._mc_flags = 0;
88 setcontext((const ucontext_t *)ucp->uc_link);
89 abort();
90 }
91 }
92