kern_kthread.c revision 1.23 
1/*	$NetBSD: kern_kthread.c,v 1.23 2008/04/24 18:39:24 ad Exp $	*/
2
3/*-
4 * Copyright (c) 1998, 1999, 2007 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, and by Andrew Doran.
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/cdefs.h>
41__KERNEL_RCSID(0, "$NetBSD: kern_kthread.c,v 1.23 2008/04/24 18:39:24 ad Exp $");
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/kernel.h>
46#include <sys/kthread.h>
47#include <sys/proc.h>
48#include <sys/sched.h>
49#include <sys/kmem.h>
50
51#include <uvm/uvm_extern.h>
52
53/*
54 * note that stdarg.h and the ansi style va_start macro is used for both
55 * ansi and traditional c complers.
56 * XXX: this requires that stdarg.h define: va_alist and va_dcl
57 */
58#include <machine/stdarg.h>
59
60/*
61 * Fork a kernel thread.  Any process can request this to be done.
62 */
63int
64kthread_create(pri_t pri, int flag, struct cpu_info *ci,
65	       void (*func)(void *), void *arg,
66	       lwp_t **lp, const char *fmt, ...)
67{
68	lwp_t *l;
69	vaddr_t uaddr;
70	bool inmem;
71	int error;
72	va_list ap;
73
74	inmem = uvm_uarea_alloc(&uaddr);
75	if (uaddr == 0)
76		return ENOMEM;
77	error = lwp_create(&lwp0, &proc0, uaddr, inmem, LWP_DETACHED, NULL,
78	    0, func, arg, &l, SCHED_FIFO);
79	if (error) {
80		uvm_uarea_free(uaddr, curcpu());
81		return error;
82	}
83	uvm_lwp_hold(l);
84	if (fmt != NULL) {
85		l->l_name = kmem_alloc(MAXCOMLEN, KM_SLEEP);
86		if (l->l_name == NULL) {
87			lwp_exit(l);
88			return ENOMEM;
89		}
90		va_start(ap, fmt);
91		vsnprintf(l->l_name, MAXCOMLEN, fmt, ap);
92		va_end(ap);
93	}
94
95	/*
96	 * Set parameters.
97	 */
98	if ((flag & KTHREAD_INTR) != 0) {
99		KASSERT((flag & KTHREAD_MPSAFE) != 0);
100	}
101
102	if (pri == PRI_NONE) {
103		/* Minimum kernel priority level. */
104		pri = PRI_KTHREAD;
105	}
106	mutex_enter(proc0.p_lock);
107	lwp_lock(l);
108	l->l_priority = pri;
109	if (ci != NULL) {
110		if (ci != l->l_cpu) {
111			lwp_unlock_to(l, ci->ci_schedstate.spc_mutex);
112			lwp_lock(l);
113		}
114		l->l_pflag |= LP_BOUND;
115		l->l_cpu = ci;
116	}
117	if ((flag & KTHREAD_INTR) != 0)
118		l->l_pflag |= LP_INTR;
119	if ((flag & KTHREAD_MPSAFE) == 0)
120		l->l_pflag &= ~LP_MPSAFE;
121
122	/*
123	 * Set the new LWP running, unless the caller has requested
124	 * otherwise.
125	 */
126	if ((flag & KTHREAD_IDLE) == 0) {
127		l->l_stat = LSRUN;
128		sched_enqueue(l, false);
129		lwp_unlock(l);
130	} else
131		lwp_unlock_to(l, ci->ci_schedstate.spc_lwplock);
132
133	/*
134	 * The LWP is not created suspended or stopped and cannot be set
135	 * into those states later, so must be considered runnable.
136	 */
137	proc0.p_nrlwps++;
138	mutex_exit(proc0.p_lock);
139
140	/* All done! */
141	if (lp != NULL)
142		*lp = l;
143
144	return (0);
145}
146
147/*
148 * Cause a kernel thread to exit.  Assumes the exiting thread is the
149 * current context.
150 */
151void
152kthread_exit(int ecode)
153{
154	const char *name;
155	lwp_t *l = curlwp;
156
157	/* We can't do much with the exit code, so just report it. */
158	if (ecode != 0) {
159		if ((name = l->l_name) == NULL)
160			name = "unnamed";
161		printf("WARNING: kthread `%s' (%d) exits with status %d\n",
162		    name, l->l_lid, ecode);
163	}
164
165	/* And exit.. */
166	lwp_exit(l);
167
168	/*
169	 * XXX Fool the compiler.  Making exit1() __noreturn__ is a can
170	 * XXX of worms right now.
171	 */
172	for (;;)
173		;
174}
175
176/*
177 * Destroy an inactive kthread.  The kthread must be in the LSIDL state.
178 */
179void
180kthread_destroy(lwp_t *l)
181{
182
183	KASSERT((l->l_flag & LW_SYSTEM) != 0);
184	KASSERT(l->l_stat == LSIDL);
185
186	lwp_exit(l);
187}
188