kern_kthread.c revision 1.27
1/* $NetBSD: kern_kthread.c,v 1.27 2009/10/21 21:12:06 rmind Exp $ */ 2 3/*- 4 * Copyright (c) 1998, 1999, 2007, 2009 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, and by Andrew Doran. 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 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33#include <sys/cdefs.h> 34__KERNEL_RCSID(0, "$NetBSD: kern_kthread.c,v 1.27 2009/10/21 21:12:06 rmind Exp $"); 35 36#include <sys/param.h> 37#include <sys/systm.h> 38#include <sys/kernel.h> 39#include <sys/kthread.h> 40#include <sys/proc.h> 41#include <sys/sched.h> 42#include <sys/kmem.h> 43 44#include <uvm/uvm_extern.h> 45 46/* 47 * note that stdarg.h and the ansi style va_start macro is used for both 48 * ansi and traditional c complers. 49 * XXX: this requires that stdarg.h define: va_alist and va_dcl 50 */ 51#include <machine/stdarg.h> 52 53/* 54 * Fork a kernel thread. Any process can request this to be done. 55 */ 56int 57kthread_create(pri_t pri, int flag, struct cpu_info *ci, 58 void (*func)(void *), void *arg, 59 lwp_t **lp, const char *fmt, ...) 60{ 61 lwp_t *l; 62 vaddr_t uaddr; 63 int error; 64 va_list ap; 65 int lc; 66 67 uaddr = uvm_uarea_alloc(); 68 if (uaddr == 0) { 69 return ENOMEM; 70 } 71 if ((flag & KTHREAD_TS) != 0) { 72 lc = SCHED_OTHER; 73 } else { 74 lc = SCHED_RR; 75 } 76 error = lwp_create(&lwp0, &proc0, uaddr, LWP_DETACHED, NULL, 77 0, func, arg, &l, lc); 78 if (error) { 79 uvm_uarea_free(uaddr); 80 return error; 81 } 82 if (fmt != NULL) { 83 l->l_name = kmem_alloc(MAXCOMLEN, KM_SLEEP); 84 if (l->l_name == NULL) { 85 lwp_exit(l); 86 return ENOMEM; 87 } 88 va_start(ap, fmt); 89 vsnprintf(l->l_name, MAXCOMLEN, fmt, ap); 90 va_end(ap); 91 } 92 93 /* 94 * Set parameters. 95 */ 96 if ((flag & KTHREAD_INTR) != 0) { 97 KASSERT((flag & KTHREAD_MPSAFE) != 0); 98 } 99 100 if (pri == PRI_NONE) { 101 if ((flag & KTHREAD_TS) != 0) { 102 /* Maximum user priority level. */ 103 pri = MAXPRI_USER; 104 } else { 105 /* Minimum kernel priority level. */ 106 pri = PRI_KTHREAD; 107 } 108 } 109 mutex_enter(proc0.p_lock); 110 lwp_lock(l); 111 l->l_priority = pri; 112 if (ci != NULL) { 113 if (ci != l->l_cpu) { 114 lwp_unlock_to(l, ci->ci_schedstate.spc_mutex); 115 lwp_lock(l); 116 } 117 l->l_pflag |= LP_BOUND; 118 l->l_cpu = ci; 119 } 120 if ((flag & KTHREAD_INTR) != 0) 121 l->l_pflag |= LP_INTR; 122 if ((flag & KTHREAD_MPSAFE) == 0) 123 l->l_pflag &= ~LP_MPSAFE; 124 125 /* 126 * Set the new LWP running, unless the caller has requested 127 * otherwise. 128 */ 129 if ((flag & KTHREAD_IDLE) == 0) { 130 l->l_stat = LSRUN; 131 sched_enqueue(l, false); 132 lwp_unlock(l); 133 } else 134 lwp_unlock_to(l, ci->ci_schedstate.spc_lwplock); 135 136 /* 137 * The LWP is not created suspended or stopped and cannot be set 138 * into those states later, so must be considered runnable. 139 */ 140 proc0.p_nrlwps++; 141 mutex_exit(proc0.p_lock); 142 143 /* All done! */ 144 if (lp != NULL) 145 *lp = l; 146 147 return (0); 148} 149 150/* 151 * Cause a kernel thread to exit. Assumes the exiting thread is the 152 * current context. 153 */ 154void 155kthread_exit(int ecode) 156{ 157 const char *name; 158 lwp_t *l = curlwp; 159 160 /* We can't do much with the exit code, so just report it. */ 161 if (ecode != 0) { 162 if ((name = l->l_name) == NULL) 163 name = "unnamed"; 164 printf("WARNING: kthread `%s' (%d) exits with status %d\n", 165 name, l->l_lid, ecode); 166 } 167 168 /* And exit.. */ 169 lwp_exit(l); 170 171 /* 172 * XXX Fool the compiler. Making exit1() __noreturn__ is a can 173 * XXX of worms right now. 174 */ 175 for (;;) 176 ; 177} 178 179/* 180 * Destroy an inactive kthread. The kthread must be in the LSIDL state. 181 */ 182void 183kthread_destroy(lwp_t *l) 184{ 185 186 KASSERT((l->l_flag & LW_SYSTEM) != 0); 187 KASSERT(l->l_stat == LSIDL); 188 189 lwp_exit(l); 190} 191