1 /* $NetBSD: _lwp.c,v 1.9 2023/04/02 07:26:17 skrll 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 *
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 2023/04/02 07:26:17 skrll Exp $");
35 #endif /* LIBC_SCCS and not lint */
36
37 #include "namespace.h"
38 #include <sys/types.h>
39 #include <inttypes.h>
40 #include <ucontext.h>
41 #include <lwp.h>
42 #include <stdlib.h>
43
44 void
_lwp_makecontext(ucontext_t * u,void (* start)(void *),void * arg,void * private,caddr_t stack_base,size_t stack_size)45 _lwp_makecontext(ucontext_t *u, void (*start)(void *),
46 void *arg, void *private, caddr_t stack_base, size_t stack_size)
47 {
48 void **sp;
49
50 getcontext(u);
51 u->uc_link = NULL;
52
53 u->uc_stack.ss_sp = stack_base;
54 u->uc_stack.ss_size = stack_size;
55
56 /* LINTED uintptr_t is safe */
57 u->uc_mcontext.__gregs[_REG_EIP] = (uintptr_t)start;
58
59 /* Align to a 16-byte boundary for SSE */
60 /* LINTED uintptr_t is safe */
61 sp = (void **) (((uintptr_t)(stack_base + stack_size - 4) & ~0xf) + 4);
62
63 *--sp = arg;
64 *--sp = (void *) _lwp_exit;
65
66 /* LINTED uintptr_t is safe */
67 u->uc_mcontext.__gregs[_REG_UESP] = (uintptr_t) sp;
68
69 u->uc_mcontext._mc_tlsbase = (uintptr_t)private;
70 u->uc_flags |= _UC_TLSBASE;
71 }
72