_lwp.c revision 1.6 
1/*	$NetBSD: _lwp.c,v 1.6 2011/02/24 04:28:42 joerg 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 Wayne Knowles
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: _lwp.c,v 1.6 2011/02/24 04:28:42 joerg Exp $");
35#endif /* LIBC_SCCS and not lint */
36
37#include "namespace.h"
38#include <sys/types.h>
39#include <ucontext.h>
40#include <lwp.h>
41#include <stdlib.h>
42
43#define CALLFRAME_SIZ	24
44
45void _lwp_makecontext(ucontext_t *u, void (*start)(void *),
46	void *arg, void *private, caddr_t stack_base, size_t stack_size)
47{
48	caddr_t sp;
49	__greg_t *gr;
50
51	getcontext(u);
52	gr = u->uc_mcontext.__gregs;
53	u->uc_link = NULL;
54
55	u->uc_stack.ss_sp = stack_base;
56	u->uc_stack.ss_size = stack_size;
57	sp = stack_base + stack_size - CALLFRAME_SIZ;
58
59	gr[_REG_EPC] = (unsigned long) start;
60	gr[_REG_T9] = (unsigned long) start; /* required for .abicalls */
61	gr[_REG_RA] = (unsigned long) _lwp_exit;
62	gr[_REG_A0] = (unsigned long) arg;
63	gr[_REG_SP] = (unsigned long) sp;
64	u->uc_mcontext._mc_tlsbase = (uintptr_t)private;
65	u->uc_flags |= _UC_TLSBASE;
66}
67