xref: /freebsd/lib/libc/riscv/gen/makecontext.c (revision 559a218c9b257775fb249b67945fe4a05b7a6b9f)
1*0bfee928SRuslan Bukin /*-
2*0bfee928SRuslan Bukin  * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
3*0bfee928SRuslan Bukin  * All rights reserved.
4*0bfee928SRuslan Bukin  *
5*0bfee928SRuslan Bukin  * Portions of this software were developed by SRI International and the
6*0bfee928SRuslan Bukin  * University of Cambridge Computer Laboratory under DARPA/AFRL contract
7*0bfee928SRuslan Bukin  * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
8*0bfee928SRuslan Bukin  *
9*0bfee928SRuslan Bukin  * Portions of this software were developed by the University of Cambridge
10*0bfee928SRuslan Bukin  * Computer Laboratory as part of the CTSRD Project, with support from the
11*0bfee928SRuslan Bukin  * UK Higher Education Innovation Fund (HEIF).
12*0bfee928SRuslan Bukin  *
13*0bfee928SRuslan Bukin  * Redistribution and use in source and binary forms, with or without
14*0bfee928SRuslan Bukin  * modification, are permitted provided that the following conditions
15*0bfee928SRuslan Bukin  * are met:
16*0bfee928SRuslan Bukin  * 1. Redistributions of source code must retain the above copyright
17*0bfee928SRuslan Bukin  *    notice, this list of conditions and the following disclaimer.
18*0bfee928SRuslan Bukin  * 2. Redistributions in binary form must reproduce the above copyright
19*0bfee928SRuslan Bukin  *    notice, this list of conditions and the following disclaimer in the
20*0bfee928SRuslan Bukin  *    documentation and/or other materials provided with the distribution.
21*0bfee928SRuslan Bukin  *
22*0bfee928SRuslan Bukin  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23*0bfee928SRuslan Bukin  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24*0bfee928SRuslan Bukin  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25*0bfee928SRuslan Bukin  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26*0bfee928SRuslan Bukin  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27*0bfee928SRuslan Bukin  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28*0bfee928SRuslan Bukin  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29*0bfee928SRuslan Bukin  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30*0bfee928SRuslan Bukin  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31*0bfee928SRuslan Bukin  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32*0bfee928SRuslan Bukin  * SUCH DAMAGE.
33*0bfee928SRuslan Bukin  */
34*0bfee928SRuslan Bukin 
35*0bfee928SRuslan Bukin #include <sys/param.h>
36*0bfee928SRuslan Bukin 
37*0bfee928SRuslan Bukin #include <machine/riscvreg.h>
38*0bfee928SRuslan Bukin 
39*0bfee928SRuslan Bukin #include <inttypes.h>
40*0bfee928SRuslan Bukin #include <stdarg.h>
41*0bfee928SRuslan Bukin #include <stdlib.h>
42*0bfee928SRuslan Bukin #include <ucontext.h>
43*0bfee928SRuslan Bukin 
44*0bfee928SRuslan Bukin void _ctx_start(void);
45*0bfee928SRuslan Bukin 
46*0bfee928SRuslan Bukin void
ctx_done(ucontext_t * ucp)47*0bfee928SRuslan Bukin ctx_done(ucontext_t *ucp)
48*0bfee928SRuslan Bukin {
49*0bfee928SRuslan Bukin 
50*0bfee928SRuslan Bukin 	if (ucp->uc_link == NULL) {
51*0bfee928SRuslan Bukin 		exit(0);
52*0bfee928SRuslan Bukin 	} else {
53*0bfee928SRuslan Bukin 		setcontext((const ucontext_t *)ucp->uc_link);
54*0bfee928SRuslan Bukin 		abort();
55*0bfee928SRuslan Bukin 	}
56*0bfee928SRuslan Bukin }
57*0bfee928SRuslan Bukin 
58*0bfee928SRuslan Bukin __weak_reference(__makecontext, makecontext);
59*0bfee928SRuslan Bukin 
60*0bfee928SRuslan Bukin void
__makecontext(ucontext_t * ucp,void (* func)(void),int argc,...)61*0bfee928SRuslan Bukin __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
62*0bfee928SRuslan Bukin {
63*0bfee928SRuslan Bukin 	struct gpregs *gp;
64*0bfee928SRuslan Bukin 	va_list ap;
65*0bfee928SRuslan Bukin 	int i;
66*0bfee928SRuslan Bukin 
67*0bfee928SRuslan Bukin 	/* A valid context is required. */
68*0bfee928SRuslan Bukin 	if (ucp == NULL)
69*0bfee928SRuslan Bukin 		return;
70*0bfee928SRuslan Bukin 
71*0bfee928SRuslan Bukin 	if ((argc < 0) || (argc > 8))
72*0bfee928SRuslan Bukin 		return;
73*0bfee928SRuslan Bukin 
74*0bfee928SRuslan Bukin 	gp = &ucp->uc_mcontext.mc_gpregs;
75*0bfee928SRuslan Bukin 
76*0bfee928SRuslan Bukin 	va_start(ap, argc);
77*0bfee928SRuslan Bukin 	/* Pass up to eight arguments in a0-7. */
78*0bfee928SRuslan Bukin 	for (i = 0; i < argc && i < 8; i++)
79*0bfee928SRuslan Bukin 		gp->gp_a[i] = va_arg(ap, uint64_t);
80*0bfee928SRuslan Bukin 	va_end(ap);
81*0bfee928SRuslan Bukin 
82*0bfee928SRuslan Bukin 	/* Set the stack */
83*0bfee928SRuslan Bukin 	gp->gp_sp = STACKALIGN(ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
84*0bfee928SRuslan Bukin 	/* Arrange for return via the trampoline code. */
85*0bfee928SRuslan Bukin 	gp->gp_sepc = (__register_t)_ctx_start;
86*0bfee928SRuslan Bukin 	gp->gp_s[0] = (__register_t)func;
87*0bfee928SRuslan Bukin 	gp->gp_s[1] = (__register_t)ucp;
88*0bfee928SRuslan Bukin }
89