makecontext.c revision 294227 
1/*-
2 * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
3 * All rights reserved.
4 *
5 * Portions of this software were developed by SRI International and the
6 * University of Cambridge Computer Laboratory under DARPA/AFRL contract
7 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
8 *
9 * Portions of this software were developed by the University of Cambridge
10 * Computer Laboratory as part of the CTSRD Project, with support from the
11 * UK Higher Education Innovation Fund (HEIF).
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: head/lib/libc/riscv/gen/makecontext.c 294227 2016-01-17 15:21:23Z br $");
37
38#include <sys/param.h>
39
40#include <machine/riscvreg.h>
41
42#include <inttypes.h>
43#include <stdarg.h>
44#include <stdlib.h>
45#include <ucontext.h>
46
47void _ctx_start(void);
48
49void
50ctx_done(ucontext_t *ucp)
51{
52
53	if (ucp->uc_link == NULL) {
54		exit(0);
55	} else {
56		setcontext((const ucontext_t *)ucp->uc_link);
57		abort();
58	}
59}
60
61__weak_reference(__makecontext, makecontext);
62
63void
64__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
65{
66	struct gpregs *gp;
67	va_list ap;
68	int i;
69
70	/* A valid context is required. */
71	if (ucp == NULL)
72		return;
73
74	if ((argc < 0) || (argc > 8))
75		return;
76
77	gp = &ucp->uc_mcontext.mc_gpregs;
78
79	va_start(ap, argc);
80	/* Pass up to eight arguments in a0-7. */
81	for (i = 0; i < argc && i < 8; i++)
82		gp->gp_a[i] = va_arg(ap, uint64_t);
83	va_end(ap);
84
85	/* Set the stack */
86	gp->gp_sp = STACKALIGN(ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
87	/* Arrange for return via the trampoline code. */
88	gp->gp_sepc = (__register_t)_ctx_start;
89	gp->gp_s[0] = (__register_t)func;
90	gp->gp_s[1] = (__register_t)ucp;
91}
92