kern_kthread.c revision 1.12
1/* $NetBSD: kern_kthread.c,v 1.12 2001/11/12 15:25:10 lukem 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/cdefs.h> 41__KERNEL_RCSID(0, "$NetBSD: kern_kthread.c,v 1.12 2001/11/12 15:25:10 lukem 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/wait.h> 49#include <sys/malloc.h> 50#include <sys/queue.h> 51 52/* 53 * note that stdarg.h and the ansi style va_start macro is used for both 54 * ansi and traditional c complers. 55 * XXX: this requires that stdarg.h define: va_alist and va_dcl 56 */ 57#include <machine/stdarg.h> 58 59int kthread_create_now; 60 61/* 62 * Fork a kernel thread. Any process can request this to be done. 63 * The VM space and limits, etc. will be shared with proc0. 64 */ 65int 66kthread_create1(void (*func)(void *), void *arg, 67 struct proc **newpp, const char *fmt, ...) 68{ 69 struct proc *p2; 70 int error; 71 va_list ap; 72 73 /* First, create the new process. */ 74 error = fork1(&proc0, FORK_SHAREVM | FORK_SHARECWD | FORK_SHAREFILES | 75 FORK_SHARESIGS, SIGCHLD, NULL, 0, func, arg, NULL, &p2); 76 if (__predict_false(error != 0)) 77 return (error); 78 79 /* 80 * Mark it as a system process and not a candidate for 81 * swapping. Set P_NOCLDWAIT so that children are reparented 82 * to init(8) when they exit. init(8) can easily wait them 83 * out for us. 84 */ 85 p2->p_flag |= P_INMEM | P_SYSTEM | P_NOCLDWAIT; /* XXX */ 86 87 /* Name it as specified. */ 88 va_start(ap, fmt); 89 vsnprintf(p2->p_comm, MAXCOMLEN, fmt, ap); 90 va_end(ap); 91 92 /* All done! */ 93 if (newpp != NULL) 94 *newpp = p2; 95 return (0); 96} 97 98/* 99 * Cause a kernel thread to exit. Assumes the exiting thread is the 100 * current context. 101 */ 102void 103kthread_exit(int ecode) 104{ 105 106 /* 107 * XXX What do we do with the exit code? Should we even bother 108 * XXX with it? The parent (proc0) isn't going to do much with 109 * XXX it. 110 */ 111 if (ecode != 0) 112 printf("WARNING: thread `%s' (%d) exits with status %d\n", 113 curproc->p_comm, curproc->p_pid, ecode); 114 115 exit1(curproc, W_EXITCODE(ecode, 0)); 116 117 /* 118 * XXX Fool the compiler. Making exit1() __noreturn__ is a can 119 * XXX of worms right now. 120 */ 121 for (;;); 122} 123 124struct kthread_q { 125 SIMPLEQ_ENTRY(kthread_q) kq_q; 126 void (*kq_func)(void *); 127 void *kq_arg; 128}; 129 130SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q); 131 132/* 133 * Defer the creation of a kernel thread. Once the standard kernel threads 134 * and processes have been created, this queue will be run to callback to 135 * the caller to create threads for e.g. file systems and device drivers. 136 */ 137void 138kthread_create(void (*func)(void *), void *arg) 139{ 140 struct kthread_q *kq; 141 142 if (kthread_create_now) { 143 (*func)(arg); 144 return; 145 } 146 147 kq = malloc(sizeof(*kq), M_TEMP, M_NOWAIT); 148 if (kq == NULL) 149 panic("unable to allocate kthread_q"); 150 memset(kq, 0, sizeof(*kq)); 151 152 kq->kq_func = func; 153 kq->kq_arg = arg; 154 155 SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q); 156} 157 158void 159kthread_run_deferred_queue(void) 160{ 161 struct kthread_q *kq; 162 163 /* No longer need to defer kthread creation. */ 164 kthread_create_now = 1; 165 166 while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) { 167 SIMPLEQ_REMOVE_HEAD(&kthread_q, kq, kq_q); 168 (*kq->kq_func)(kq->kq_arg); 169 free(kq, M_TEMP); 170 } 171} 172