1 /* $OpenBSD: kern_kthread.c,v 1.26 2006/11/29 12:24:17 miod Exp $ */ 2 /* $NetBSD: kern_kthread.c,v 1.3 1998/12/22 21:21:36 kleink Exp $ */ 3 4 /*- 5 * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 10 * NASA Ames Research Center. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the NetBSD 23 * Foundation, Inc. and its contributors. 24 * 4. Neither the name of The NetBSD Foundation nor the names of its 25 * contributors may be used to endorse or promote products derived 26 * from this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 38 * POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kernel.h> 44 #include <sys/kthread.h> 45 #include <sys/proc.h> 46 #include <sys/wait.h> 47 #include <sys/malloc.h> 48 #include <sys/queue.h> 49 50 #include <machine/cpu.h> 51 52 /* 53 * note that stdarg.h and the ansi style va_start macro is used for both 54 * ansi and traditional c compilers. 55 * XXX: this requires that stdarg.h define: va_alist and va_dcl 56 */ 57 #include <sys/stdarg.h> 58 59 int 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 */ 65 int 66 kthread_create(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 /* 74 * First, create the new process. Share the memory, file 75 * descriptors and don't leave the exit status around for the 76 * parent to wait for. 77 */ 78 error = fork1(&proc0, 0, FORK_SHAREVM |FORK_NOZOMBIE |FORK_SIGHAND, 79 NULL, 0, func, arg, NULL, &p2); 80 if (error) 81 return (error); 82 83 /* 84 * Mark it as a system process. 85 */ 86 p2->p_flag |= P_SYSTEM; 87 88 /* Name it as specified. */ 89 va_start(ap, fmt); 90 vsnprintf(p2->p_comm, sizeof p2->p_comm, fmt, ap); 91 va_end(ap); 92 93 /* All done! */ 94 if (newpp != NULL) 95 *newpp = p2; 96 return (0); 97 } 98 99 /* 100 * Cause a kernel thread to exit. Assumes the exiting thread is the 101 * current context. 102 */ 103 void 104 kthread_exit(int ecode) 105 { 106 107 /* 108 * XXX What do we do with the exit code? Should we even bother 109 * XXX with it? The parent (proc0) isn't going to do much with 110 * XXX it. 111 */ 112 if (ecode != 0) 113 printf("WARNING: thread `%s' (%d) exits with status %d\n", 114 curproc->p_comm, curproc->p_pid, ecode); 115 116 exit1(curproc, W_EXITCODE(ecode, 0), EXIT_NORMAL); 117 118 /* 119 * XXX Fool the compiler. Making exit1() __dead is a can 120 * XXX of worms right now. 121 */ 122 for (;;); 123 } 124 125 struct kthread_q { 126 SIMPLEQ_ENTRY(kthread_q) kq_q; 127 void (*kq_func)(void *); 128 void *kq_arg; 129 }; 130 131 SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q); 132 133 /* 134 * Defer the creation of a kernel thread. Once the standard kernel threads 135 * and processes have been created, this queue will be run to callback to 136 * the caller to create threads for e.g. file systems and device drivers. 137 */ 138 void 139 kthread_create_deferred(void (*func)(void *), void *arg) 140 { 141 struct kthread_q *kq; 142 143 if (kthread_create_now) { 144 (*func)(arg); 145 return; 146 } 147 148 kq = malloc(sizeof *kq, M_TEMP, M_NOWAIT); 149 if (kq == NULL) 150 panic("unable to allocate kthread_q"); 151 bzero(kq, sizeof *kq); 152 153 kq->kq_func = func; 154 kq->kq_arg = arg; 155 156 SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q); 157 } 158 159 void 160 kthread_run_deferred_queue(void) 161 { 162 struct kthread_q *kq; 163 164 /* No longer need to defer kthread creation. */ 165 kthread_create_now = 1; 166 167 while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) { 168 SIMPLEQ_REMOVE_HEAD(&kthread_q, kq_q); 169 (*kq->kq_func)(kq->kq_arg); 170 free(kq, M_TEMP); 171 } 172 } 173