kern_kthread.c revision 1.25 
1/*	$NetBSD: kern_kthread.c,v 1.25 2009/01/29 22:00:26 ad Exp $	*/
2
3/*-
4 * Copyright (c) 1998, 1999, 2007, 2009 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 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33#include <sys/cdefs.h>
34__KERNEL_RCSID(0, "$NetBSD: kern_kthread.c,v 1.25 2009/01/29 22:00:26 ad Exp $");
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/kernel.h>
39#include <sys/kthread.h>
40#include <sys/proc.h>
41#include <sys/sched.h>
42#include <sys/kmem.h>
43
44#include <uvm/uvm_extern.h>
45
46/*
47 * note that stdarg.h and the ansi style va_start macro is used for both
48 * ansi and traditional c complers.
49 * XXX: this requires that stdarg.h define: va_alist and va_dcl
50 */
51#include <machine/stdarg.h>
52
53/*
54 * Fork a kernel thread.  Any process can request this to be done.
55 */
56int
57kthread_create(pri_t pri, int flag, struct cpu_info *ci,
58	       void (*func)(void *), void *arg,
59	       lwp_t **lp, const char *fmt, ...)
60{
61	lwp_t *l;
62	vaddr_t uaddr;
63	bool inmem;
64	int error;
65	va_list ap;
66	int lc;
67
68	inmem = uvm_uarea_alloc(&uaddr);
69	if (uaddr == 0)
70		return ENOMEM;
71	if ((flags & KTHREAD_TS) != 0) {
72		lc = SCHED_OTHER;
73	} else {
74		lc = SCHED_RR;
75	}
76	error = lwp_create(&lwp0, &proc0, uaddr, inmem, LWP_DETACHED, NULL,
77	    0, func, arg, &l, lc);
78	if (error) {
79		uvm_uarea_free(uaddr, curcpu());
80		return error;
81	}
82	uvm_lwp_hold(l);
83	if (fmt != NULL) {
84		l->l_name = kmem_alloc(MAXCOMLEN, KM_SLEEP);
85		if (l->l_name == NULL) {
86			lwp_exit(l);
87			return ENOMEM;
88		}
89		va_start(ap, fmt);
90		vsnprintf(l->l_name, MAXCOMLEN, fmt, ap);
91		va_end(ap);
92	}
93
94	/*
95	 * Set parameters.
96	 */
97	if ((flag & KTHREAD_INTR) != 0) {
98		KASSERT((flag & KTHREAD_MPSAFE) != 0);
99	}
100
101	if (pri == PRI_NONE) {
102		if ((flags & KTHREAD_TS) != 0) {
103			/* Maximum user priority level. */
104			pri = MAXPRI_USER;
105		} else {
106			/* Minimum kernel priority level. */
107			pri = PRI_KTHREAD;
108		}
109	}
110	mutex_enter(proc0.p_lock);
111	lwp_lock(l);
112	l->l_priority = pri;
113	if (ci != NULL) {
114		if (ci != l->l_cpu) {
115			lwp_unlock_to(l, ci->ci_schedstate.spc_mutex);
116			lwp_lock(l);
117		}
118		l->l_pflag |= LP_BOUND;
119		l->l_cpu = ci;
120	}
121	if ((flag & KTHREAD_INTR) != 0)
122		l->l_pflag |= LP_INTR;
123	if ((flag & KTHREAD_MPSAFE) == 0)
124		l->l_pflag &= ~LP_MPSAFE;
125
126	/*
127	 * Set the new LWP running, unless the caller has requested
128	 * otherwise.
129	 */
130	if ((flag & KTHREAD_IDLE) == 0) {
131		l->l_stat = LSRUN;
132		sched_enqueue(l, false);
133		lwp_unlock(l);
134	} else
135		lwp_unlock_to(l, ci->ci_schedstate.spc_lwplock);
136
137	/*
138	 * The LWP is not created suspended or stopped and cannot be set
139	 * into those states later, so must be considered runnable.
140	 */
141	proc0.p_nrlwps++;
142	mutex_exit(proc0.p_lock);
143
144	/* All done! */
145	if (lp != NULL)
146		*lp = l;
147
148	return (0);
149}
150
151/*
152 * Cause a kernel thread to exit.  Assumes the exiting thread is the
153 * current context.
154 */
155void
156kthread_exit(int ecode)
157{
158	const char *name;
159	lwp_t *l = curlwp;
160
161	/* We can't do much with the exit code, so just report it. */
162	if (ecode != 0) {
163		if ((name = l->l_name) == NULL)
164			name = "unnamed";
165		printf("WARNING: kthread `%s' (%d) exits with status %d\n",
166		    name, l->l_lid, ecode);
167	}
168
169	/* And exit.. */
170	lwp_exit(l);
171
172	/*
173	 * XXX Fool the compiler.  Making exit1() __noreturn__ is a can
174	 * XXX of worms right now.
175	 */
176	for (;;)
177		;
178}
179
180/*
181 * Destroy an inactive kthread.  The kthread must be in the LSIDL state.
182 */
183void
184kthread_destroy(lwp_t *l)
185{
186
187	KASSERT((l->l_flag & LW_SYSTEM) != 0);
188	KASSERT(l->l_stat == LSIDL);
189
190	lwp_exit(l);
191}
192