xref: /netbsd-src/lib/libc/arch/i386/gen/_lwp.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: _lwp.c,v 1.5 2005/06/12 05:21:26 lukem 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 Nathan J. Williams.
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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
41 __RCSID("$NetBSD: _lwp.c,v 1.5 2005/06/12 05:21:26 lukem Exp $");
42 #endif /* LIBC_SCCS and not lint */
43 
44 #include "namespace.h"
45 #include <sys/types.h>
46 #include <inttypes.h>
47 #include <ucontext.h>
48 #include <lwp.h>
49 #include <stdlib.h>
50 
51 void
52 _lwp_makecontext(ucontext_t *u, void (*start)(void *),
53     void *arg, void *private, caddr_t stack_base, size_t stack_size)
54 {
55 	void **sp;
56 
57 	getcontext(u);
58 	u->uc_link = NULL;
59 
60 	u->uc_stack.ss_sp = stack_base;
61 	u->uc_stack.ss_size = stack_size;
62 
63 	/* LINTED uintptr_t is safe */
64 	u->uc_mcontext.__gregs[_REG_EIP] = (uintptr_t)start;
65 
66 	/* Align to a word */
67 	/* LINTED uintptr_t is safe */
68 	sp = (void **) ((uintptr_t)(stack_base + stack_size) & ~0x3);
69 
70 	*--sp = arg;
71 	*--sp = (void *) _lwp_exit;
72 
73 	/* LINTED uintptr_t is safe */
74 	u->uc_mcontext.__gregs[_REG_UESP] = (uintptr_t) sp;
75 
76 	/* LINTED private is currently unused */
77 }
78