1 /* $NetBSD: makecontext.c,v 1.5 2012/03/17 21:35:06 martin Exp $ */
2
3 /*-
4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Klaus Klein.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 __RCSID("$NetBSD: makecontext.c,v 1.5 2012/03/17 21:35:06 martin Exp $");
35 #endif
36
37 #include <inttypes.h>
38 #include <stddef.h>
39 #include <sys/types.h>
40 #include <ucontext.h>
41 #include "extern.h"
42
43 #include <stdarg.h>
44
45 void
makecontext(ucontext_t * ucp,void (* func)(void),int argc,...)46 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
47 {
48 __greg_t *gr = ucp->uc_mcontext.__gregs;
49 int i;
50 ulong *sp;
51 va_list ap;
52
53 /*LINTED*/
54 sp = (ulong *)((caddr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
55 /* Align on quad-word boundary. */
56 sp = (ulong *)((ulong)sp & ~0xf);
57
58 /* Make room for: argx, argd, struct return pointer(?), rwindow. */
59 sp -= (argc > 6 ? argc - 6 : 0) + 6 + 8 + 8;
60
61 va_start(ap, argc);
62
63 /* Pass up to 6 arguments in %o0-5. */
64 for (i = 0; i < argc && i < 6; i++)
65 gr[_REG_O0 + i] = sp[i + 16] = va_arg(ap, unsigned long);
66
67 /* Pass any additional arguments on the stack. */
68 for (; i < argc; i++)
69 sp[i + 16] = va_arg(ap, unsigned long);
70 va_end(ap);
71
72 sp[14] = (ulong)sp - 2047;
73 sp[15] = (ulong)_resumecontext - 8;
74
75 /*LINTED*/
76 sp = (ulong *)((caddr_t)sp - 2047);
77
78 gr[_REG_O6] = (__greg_t)sp;
79 gr[_REG_PC] = (__greg_t)func;
80 gr[_REG_nPC] = (__greg_t)func + 4;
81 gr[_REG_O7] = (__greg_t)_resumecontext - 8;
82
83 }
84