1 /* $NetBSD: kern_kthread.c,v 1.15 2003/01/18 10:06:26 thorpej 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 1.15 2003/01/18 10:06:26 thorpej 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 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_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(&lwp0, 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_SYSTEM | P_NOCLDWAIT; 86 LIST_FIRST(&p2->p_lwps)->l_flag |= L_INMEM; 87 88 /* Name it as specified. */ 89 va_start(ap, fmt); 90 vsnprintf(p2->p_comm, MAXCOMLEN, 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(curlwp, W_EXITCODE(ecode, 0)); 117 118 /* 119 * XXX Fool the compiler. Making exit1() __noreturn__ 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(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 memset(kq, 0, 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