_lwp.c revision 1.8 
1/*	$NetBSD: _lwp.c,v 1.8 2011/04/29 08:05:22 matt 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 1.8 2011/04/29 08:05:22 matt 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#if defined(__mips_o32) || defined(__mips_o64)
44#define CALLFRAME_SIZ	(6 * sizeof(void *))
45#else
46#define CALLFRAME_SIZ	(4 * sizeof(uint64_t))
47#endif
48
49void
50_lwp_makecontext(ucontext_t *u, void (*start)(void *),
51	void *arg, void *tcb, caddr_t stack_base, size_t stack_size)
52{
53	caddr_t sp;
54	__greg_t *gr;
55
56	getcontext(u);
57	gr = u->uc_mcontext.__gregs;
58	u->uc_link = NULL;
59
60	u->uc_stack.ss_sp = stack_base;
61	u->uc_stack.ss_size = stack_size;
62	sp = stack_base + stack_size - CALLFRAME_SIZ;
63
64	gr[_REG_EPC] = (uintptr_t) start;
65	gr[_REG_T9] = (uintptr_t) start; /* required for .abicalls */
66	gr[_REG_RA] = (uintptr_t) _lwp_exit;
67	gr[_REG_A0] = (uintptr_t) arg;
68	gr[_REG_SP] = (uintptr_t) sp;
69	u->uc_mcontext._mc_tlsbase =
70	    (uintptr_t)tcb + TLS_TP_OFFSET + sizeof(struct tls_tcb);
71	u->uc_flags |= _UC_TLSBASE;
72}
73