1 /* $OpenBSD: kern_kthread.c,v 1.34 2014/02/12 05:47:36 guenther 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 * 21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/kernel.h> 37 #include <sys/kthread.h> 38 #include <sys/proc.h> 39 #include <sys/wait.h> 40 #include <sys/malloc.h> 41 #include <sys/queue.h> 42 43 44 /* 45 * note that stdarg.h and the ansi style va_start macro is used for both 46 * ansi and traditional c compilers. 47 * XXX: this requires that stdarg.h define: va_alist and va_dcl 48 */ 49 #include <sys/stdarg.h> 50 51 int kthread_create_now; 52 53 /* 54 * Fork a kernel thread. Any process can request this to be done. 55 * The VM space and limits, etc. will be shared with proc0. 56 */ 57 int 58 kthread_create(void (*func)(void *), void *arg, 59 struct proc **newpp, const char *name) 60 { 61 struct proc *p; 62 int error; 63 64 /* 65 * First, create the new process. Share the memory, file 66 * descriptors and don't leave the exit status around for the 67 * parent to wait for. 68 */ 69 error = fork1(&proc0, FORK_SHAREVM|FORK_SHAREFILES|FORK_NOZOMBIE| 70 FORK_SIGHAND, NULL, 0, func, arg, NULL, &p); 71 if (error) 72 return (error); 73 74 /* 75 * Mark it as a system process. 76 */ 77 atomic_setbits_int(&p->p_flag, P_SYSTEM); 78 79 /* Name it as specified. */ 80 strlcpy(p->p_comm, name, sizeof p->p_comm); 81 82 /* All done! */ 83 if (newpp != NULL) 84 *newpp = p; 85 return (0); 86 } 87 88 /* 89 * Cause a kernel thread to exit. Assumes the exiting thread is the 90 * current context. 91 */ 92 void 93 kthread_exit(int ecode) 94 { 95 96 /* 97 * XXX What do we do with the exit code? Should we even bother 98 * XXX with it? The parent (proc0) isn't going to do much with 99 * XXX it. 100 */ 101 if (ecode != 0) 102 printf("WARNING: thread `%s' (%d) exits with status %d\n", 103 curproc->p_comm, curproc->p_pid, ecode); 104 105 exit1(curproc, W_EXITCODE(ecode, 0), EXIT_NORMAL); 106 107 /* 108 * XXX Fool the compiler. Making exit1() __dead is a can 109 * XXX of worms right now. 110 */ 111 for (;;); 112 } 113 114 struct kthread_q { 115 SIMPLEQ_ENTRY(kthread_q) kq_q; 116 void (*kq_func)(void *); 117 void *kq_arg; 118 }; 119 120 SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q); 121 122 /* 123 * Defer the creation of a kernel thread. Once the standard kernel threads 124 * and processes have been created, this queue will be run to callback to 125 * the caller to create threads for e.g. file systems and device drivers. 126 */ 127 void 128 kthread_create_deferred(void (*func)(void *), void *arg) 129 { 130 struct kthread_q *kq; 131 132 if (kthread_create_now) { 133 (*func)(arg); 134 return; 135 } 136 137 kq = malloc(sizeof *kq, M_TEMP, M_NOWAIT|M_ZERO); 138 if (kq == NULL) 139 panic("unable to allocate kthread_q"); 140 141 kq->kq_func = func; 142 kq->kq_arg = arg; 143 144 SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q); 145 } 146 147 void 148 kthread_run_deferred_queue(void) 149 { 150 struct kthread_q *kq; 151 152 /* No longer need to defer kthread creation. */ 153 kthread_create_now = 1; 154 155 while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) { 156 SIMPLEQ_REMOVE_HEAD(&kthread_q, kq_q); 157 (*kq->kq_func)(kq->kq_arg); 158 free(kq, M_TEMP); 159 } 160 } 161