1 /* $OpenBSD: kern_kthread.c,v 1.41 2017/02/12 04:55:08 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/kthread.h> 37 #include <sys/proc.h> 38 #include <sys/wait.h> 39 #include <sys/malloc.h> 40 #include <sys/queue.h> 41 42 43 /* 44 * note that stdarg.h and the ansi style va_start macro is used for both 45 * ansi and traditional c compilers. 46 * XXX: this requires that stdarg.h define: va_alist and va_dcl 47 */ 48 #include <sys/stdarg.h> 49 50 int kthread_create_now; 51 52 /* 53 * Fork a kernel thread. Any process can request this to be done. 54 * The VM space and limits, etc. will be shared with proc0. 55 */ 56 int 57 kthread_create(void (*func)(void *), void *arg, 58 struct proc **newpp, const char *name) 59 { 60 struct proc *p; 61 int error; 62 63 /* 64 * First, create the new process. Share the memory, file 65 * descriptors and don't leave the exit status around for the 66 * parent to wait for. 67 */ 68 error = fork1(&proc0, FORK_SHAREVM|FORK_SHAREFILES|FORK_NOZOMBIE| 69 FORK_SYSTEM|FORK_SIGHAND, func, arg, NULL, &p); 70 if (error) 71 return (error); 72 73 /* Name it as specified. */ 74 strlcpy(p->p_p->ps_comm, name, sizeof p->p_p->ps_comm); 75 76 /* All done! */ 77 if (newpp != NULL) 78 *newpp = p; 79 return (0); 80 } 81 82 /* 83 * Cause a kernel thread to exit. Assumes the exiting thread is the 84 * current context. 85 */ 86 void 87 kthread_exit(int ecode) 88 { 89 90 /* 91 * XXX What do we do with the exit code? Should we even bother 92 * XXX with it? The parent (proc0) isn't going to do much with 93 * XXX it. 94 */ 95 if (ecode != 0) 96 printf("WARNING: thread `%s' (%d) exits with status %d\n", 97 curproc->p_p->ps_comm, curproc->p_tid, ecode); 98 99 exit1(curproc, W_EXITCODE(ecode, 0), EXIT_NORMAL); 100 101 /* 102 * XXX Fool the compiler. Making exit1() __dead is a can 103 * XXX of worms right now. 104 */ 105 for (;;); 106 } 107 108 struct kthread_q { 109 SIMPLEQ_ENTRY(kthread_q) kq_q; 110 void (*kq_func)(void *); 111 void *kq_arg; 112 }; 113 114 SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q); 115 116 /* 117 * Defer the creation of a kernel thread. Once the standard kernel threads 118 * and processes have been created, this queue will be run to callback to 119 * the caller to create threads for e.g. file systems and device drivers. 120 */ 121 void 122 kthread_create_deferred(void (*func)(void *), void *arg) 123 { 124 struct kthread_q *kq; 125 126 if (kthread_create_now) { 127 (*func)(arg); 128 return; 129 } 130 131 kq = malloc(sizeof *kq, M_TEMP, M_NOWAIT|M_ZERO); 132 if (kq == NULL) 133 panic("unable to allocate kthread_q"); 134 135 kq->kq_func = func; 136 kq->kq_arg = arg; 137 138 SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q); 139 } 140 141 void 142 kthread_run_deferred_queue(void) 143 { 144 struct kthread_q *kq; 145 146 /* No longer need to defer kthread creation. */ 147 kthread_create_now = 1; 148 149 while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) { 150 SIMPLEQ_REMOVE_HEAD(&kthread_q, kq_q); 151 (*kq->kq_func)(kq->kq_arg); 152 free(kq, M_TEMP, sizeof(*kq)); 153 } 154 } 155