_lwp.c revision 1.9 
1/*	$NetBSD: _lwp.c,v 1.9 2024/11/30 01:04:03 christos 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 1.9 2024/11/30 01:04:03 christos 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#include <machine/lwp_private.h>
44
45#if defined(__mips_o32) || defined(__mips_o64)
46#define CALLFRAME_SIZ	(6 * sizeof(void *))
47#else
48#define CALLFRAME_SIZ	(4 * sizeof(uint64_t))
49#endif
50
51void
52_lwp_makecontext(ucontext_t *u, void (*start)(void *),
53	void *arg, void *tcb, caddr_t stack_base, size_t stack_size)
54{
55	caddr_t sp;
56	__greg_t *gr;
57
58	getcontext(u);
59	gr = u->uc_mcontext.__gregs;
60	u->uc_link = NULL;
61
62	u->uc_stack.ss_sp = stack_base;
63	u->uc_stack.ss_size = stack_size;
64	sp = stack_base + stack_size - CALLFRAME_SIZ;
65
66	gr[_REG_EPC] = (uintptr_t) start;
67	gr[_REG_T9] = (uintptr_t) start; /* required for .abicalls */
68	gr[_REG_RA] = (uintptr_t) _lwp_exit;
69	gr[_REG_A0] = (uintptr_t) arg;
70	gr[_REG_SP] = (uintptr_t) sp;
71	u->uc_mcontext._mc_tlsbase =
72	    (uintptr_t)tcb + TLS_TP_OFFSET + sizeof(struct tls_tcb);
73	u->uc_flags |= _UC_TLSBASE;
74}
75