xref: /netbsd-src/lib/libc/arch/i386/gen/_lwp.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: _lwp.c,v 1.4 2003/05/30 07:23:25 kleink 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 "namespace.h"
40 #include <sys/types.h>
41 #include <inttypes.h>
42 #include <ucontext.h>
43 #include <lwp.h>
44 #include <stdlib.h>
45 
46 void
47 _lwp_makecontext(ucontext_t *u, void (*start)(void *),
48     void *arg, void *private, caddr_t stack_base, size_t stack_size)
49 {
50 	void **sp;
51 
52 	getcontext(u);
53 	u->uc_link = NULL;
54 
55 	u->uc_stack.ss_sp = stack_base;
56 	u->uc_stack.ss_size = stack_size;
57 
58 	/* LINTED uintptr_t is safe */
59 	u->uc_mcontext.__gregs[_REG_EIP] = (uintptr_t)start;
60 
61 	/* Align to a word */
62 	/* LINTED uintptr_t is safe */
63 	sp = (void **) ((uintptr_t)(stack_base + stack_size) & ~0x3);
64 
65 	*--sp = arg;
66 	*--sp = (void *) _lwp_exit;
67 
68 	/* LINTED uintptr_t is safe */
69 	u->uc_mcontext.__gregs[_REG_UESP] = (uintptr_t) sp;
70 
71 	/* LINTED private is currently unused */
72 }
73