kern_kthread.c revision 1.3 
1/*	$NetBSD: kern_kthread.c,v 1.3 1998/12/22 21:21:36 kleink Exp $	*/
2
3/*-
4 * Copyright (c) 1998 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, NULL, &p2);
79	if (error)
80		return (error);
81
82	/*
83	 * Mark it as a system process and not a candidate for
84	 * swapping.  Set P_NOCLDWAIT so that children are reparented
85	 * to init(8) when they exit.  init(8) can easily wait them
86	 * out for us.
87	 */
88	p2->p_flag |= P_INMEM | P_SYSTEM | P_NOCLDWAIT;	/* XXX */
89
90	/* Name it as specified. */
91	va_start(ap, fmt);
92	vsprintf(p2->p_comm, fmt, ap);
93	va_end(ap);
94
95	/* Arrange for it to start at the specified function. */
96	cpu_set_kpc(p2, func, arg);
97
98	/* All done! */
99	if (newpp != NULL)
100		*newpp = p2;
101	return (0);
102}
103
104/*
105 * Cause a kernel thread to exit.  Assumes the exiting thread is the
106 * current context.
107 */
108void
109kthread_exit(ecode)
110	int ecode;
111{
112
113	/*
114	 * XXX What do we do with the exit code?  Should we even bother
115	 * XXX with it?  The parent (proc0) isn't going to do much with
116	 * XXX it.
117	 */
118	if (ecode != 0)
119		printf("WARNING: thread `%s' (%d) exits with status %d\n",
120		    curproc->p_comm, curproc->p_pid, ecode);
121
122	exit1(curproc, W_EXITCODE(ecode, 0));
123
124	/*
125	 * XXX Fool the compiler.  Making exit1() __noreturn__ is a can
126	 * XXX of worms right now.
127	 */
128	for (;;);
129}
130
131struct kthread_q {
132	SIMPLEQ_ENTRY(kthread_q) kq_q;
133	void (*kq_func) __P((void *));
134	void *kq_arg;
135};
136
137SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q);
138
139/*
140 * Defer the creation of a kernel thread.  Once the standard kernel threads
141 * and processes have been created, this queue will be run to callback to
142 * the caller to create threads for e.g. file systems and device drivers.
143 */
144void
145kthread_create_deferred(func, arg)
146	void (*func) __P((void *));
147	void *arg;
148{
149	struct kthread_q *kq;
150
151	kq = malloc(sizeof(*kq), M_TEMP, M_NOWAIT);
152	if (kq == NULL)
153		panic("unable to allocate kthread_q");
154	memset(kq, 0, sizeof(*kq));
155
156	kq->kq_func = func;
157	kq->kq_arg = arg;
158
159	SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q);
160}
161
162void
163kthread_run_deferred_queue()
164{
165	struct kthread_q *kq;
166
167	while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) {
168		SIMPLEQ_REMOVE_HEAD(&kthread_q, kq, kq_q);
169		(*kq->kq_func)(kq->kq_arg);
170		free(kq, M_TEMP);
171	}
172}
173