kern_kthread.c revision 1.8 
1/*	$NetBSD: kern_kthread.c,v 1.8 1999/07/06 21:44:10 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
56int	kthread_create_now;
57
58/*
59 * Fork a kernel thread.  Any process can request this to be done.
60 * The VM space and limits, etc. will be shared with proc0.
61 */
62int
63#if __STDC__
64kthread_create1(void (*func)(void *), void *arg,
65    struct proc **newpp, const char *fmt, ...)
66#else
67kthread_create1(func, arg, newpp, fmt, va_alist)
68	void (*func) __P((void *));
69	void *arg;
70	struct proc **newpp;
71	const char *fmt;
72	va_dcl
73#endif
74{
75	struct proc *p2;
76	int error;
77	va_list ap;
78
79	/* First, create the new process. */
80	error = fork1(&proc0, FORK_SHAREVM | FORK_SHARECWD | FORK_SHAREFILES |
81	    FORK_SHARESIGS, SIGCHLD, NULL, 0, NULL, &p2);
82	if (error)
83		return (error);
84
85	/*
86	 * Mark it as a system process and not a candidate for
87	 * swapping.  Set P_NOCLDWAIT so that children are reparented
88	 * to init(8) when they exit.  init(8) can easily wait them
89	 * out for us.
90	 */
91	p2->p_flag |= P_INMEM | P_SYSTEM | P_NOCLDWAIT;	/* XXX */
92
93	/* Name it as specified. */
94	va_start(ap, fmt);
95	vsnprintf(p2->p_comm, MAXCOMLEN, fmt, ap);
96	va_end(ap);
97
98	/* Arrange for it to start at the specified function. */
99	cpu_set_kpc(p2, func, arg);
100
101	/* All done! */
102	if (newpp != NULL)
103		*newpp = p2;
104	return (0);
105}
106
107/*
108 * Cause a kernel thread to exit.  Assumes the exiting thread is the
109 * current context.
110 */
111void
112kthread_exit(ecode)
113	int ecode;
114{
115
116	/*
117	 * XXX What do we do with the exit code?  Should we even bother
118	 * XXX with it?  The parent (proc0) isn't going to do much with
119	 * XXX it.
120	 */
121	if (ecode != 0)
122		printf("WARNING: thread `%s' (%d) exits with status %d\n",
123		    curproc->p_comm, curproc->p_pid, ecode);
124
125	exit1(curproc, W_EXITCODE(ecode, 0));
126
127	/*
128	 * XXX Fool the compiler.  Making exit1() __noreturn__ is a can
129	 * XXX of worms right now.
130	 */
131	for (;;);
132}
133
134struct kthread_q {
135	SIMPLEQ_ENTRY(kthread_q) kq_q;
136	void (*kq_func) __P((void *));
137	void *kq_arg;
138};
139
140SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q);
141
142/*
143 * Defer the creation of a kernel thread.  Once the standard kernel threads
144 * and processes have been created, this queue will be run to callback to
145 * the caller to create threads for e.g. file systems and device drivers.
146 */
147void
148kthread_create(func, arg)
149	void (*func) __P((void *));
150	void *arg;
151{
152	struct kthread_q *kq;
153
154	if (kthread_create_now) {
155		(*func)(arg);
156		return;
157	}
158
159	kq = malloc(sizeof(*kq), M_TEMP, M_NOWAIT);
160	if (kq == NULL)
161		panic("unable to allocate kthread_q");
162	memset(kq, 0, sizeof(*kq));
163
164	kq->kq_func = func;
165	kq->kq_arg = arg;
166
167	SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q);
168}
169
170void
171kthread_run_deferred_queue()
172{
173	struct kthread_q *kq;
174
175	/* No longer need to defer kthread creation. */
176	kthread_create_now = 1;
177
178	while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) {
179		SIMPLEQ_REMOVE_HEAD(&kthread_q, kq, kq_q);
180		(*kq->kq_func)(kq->kq_arg);
181		free(kq, M_TEMP);
182	}
183}
184