kern_kthread.c revision 1.6 
1/*	$NetBSD: kern_kthread.c,v 1.6 1999/05/13 00:59:04 thorpej Exp $	*/
2
3/*-
4 * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the NetBSD
22 *	Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 *    contributors may be used to endorse or promote products derived
25 *    from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/kernel.h>
43#include <sys/kthread.h>
44#include <sys/proc.h>
45#include <sys/wait.h>
46#include <sys/malloc.h>
47#include <sys/queue.h>
48
49/*
50 * note that stdarg.h and the ansi style va_start macro is used for both
51 * ansi and traditional c complers.
52 * XXX: this requires that stdarg.h define: va_alist and va_dcl
53 */
54#include <machine/stdarg.h>
55
56/*
57 * Fork a kernel thread.  Any process can request this to be done.
58 * The VM space and limits, etc. will be shared with proc0.
59 */
60int
61#if __STDC__
62kthread_create(void (*func)(void *), void *arg,
63    struct proc **newpp, const char *fmt, ...)
64#else
65kthread_create(func, arg, newpp, fmt, va_alist)
66	void (*func) __P((void *));
67	void *arg;
68	struct proc **newpp;
69	const char *fmt;
70	va_dcl
71#endif
72{
73	struct proc *p2;
74	int error;
75	va_list ap;
76
77	/* First, create the new process. */
78	error = fork1(&proc0, FORK_SHAREVM | FORK_SHARECWD | FORK_SHAREFILES |
79	    FORK_SHARESIGS, SIGCHLD, NULL, &p2);
80	if (error)
81		return (error);
82
83	/*
84	 * Mark it as a system process and not a candidate for
85	 * swapping.  Set P_NOCLDWAIT so that children are reparented
86	 * to init(8) when they exit.  init(8) can easily wait them
87	 * out for us.
88	 */
89	p2->p_flag |= P_INMEM | P_SYSTEM | P_NOCLDWAIT;	/* XXX */
90
91	/* Name it as specified. */
92	va_start(ap, fmt);
93	vsnprintf(p2->p_comm, MAXCOMLEN, fmt, ap);
94	va_end(ap);
95
96	/* Arrange for it to start at the specified function. */
97	cpu_set_kpc(p2, func, arg);
98
99	/* All done! */
100	if (newpp != NULL)
101		*newpp = p2;
102	return (0);
103}
104
105/*
106 * Cause a kernel thread to exit.  Assumes the exiting thread is the
107 * current context.
108 */
109void
110kthread_exit(ecode)
111	int ecode;
112{
113
114	/*
115	 * XXX What do we do with the exit code?  Should we even bother
116	 * XXX with it?  The parent (proc0) isn't going to do much with
117	 * XXX it.
118	 */
119	if (ecode != 0)
120		printf("WARNING: thread `%s' (%d) exits with status %d\n",
121		    curproc->p_comm, curproc->p_pid, ecode);
122
123	exit1(curproc, W_EXITCODE(ecode, 0));
124
125	/*
126	 * XXX Fool the compiler.  Making exit1() __noreturn__ is a can
127	 * XXX of worms right now.
128	 */
129	for (;;);
130}
131
132struct kthread_q {
133	SIMPLEQ_ENTRY(kthread_q) kq_q;
134	void (*kq_func) __P((void *));
135	void *kq_arg;
136};
137
138SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q);
139
140/*
141 * Defer the creation of a kernel thread.  Once the standard kernel threads
142 * and processes have been created, this queue will be run to callback to
143 * the caller to create threads for e.g. file systems and device drivers.
144 */
145void
146kthread_create_deferred(func, arg)
147	void (*func) __P((void *));
148	void *arg;
149{
150	struct kthread_q *kq;
151
152	kq = malloc(sizeof(*kq), M_TEMP, M_NOWAIT);
153	if (kq == NULL)
154		panic("unable to allocate kthread_q");
155	memset(kq, 0, sizeof(*kq));
156
157	kq->kq_func = func;
158	kq->kq_arg = arg;
159
160	SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q);
161}
162
163void
164kthread_run_deferred_queue()
165{
166	struct kthread_q *kq;
167
168	while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) {
169		SIMPLEQ_REMOVE_HEAD(&kthread_q, kq, kq_q);
170		(*kq->kq_func)(kq->kq_arg);
171		free(kq, M_TEMP);
172	}
173}
174