kern_kthread.c revision 1.29
1/* $NetBSD: kern_kthread.c,v 1.29 2010/05/12 15:53:20 haad 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 1.29 2010/05/12 15:53:20 haad 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 * 56 * With joinable kthreads KTHREAD_JOINABLE flag this should be known. 57 * 1. If you specify KTHREAD_JOINABLE, you must call kthread_join() to reap 58 * the thread. It will not be automatically reaped by the system. 59 * 2. For any given call to kthread_create(KTHREAD_JOINABLE), you may call 60 * kthread_join() only once on the returned lwp_t *. 61 */ 62int 63kthread_create(pri_t pri, int flag, struct cpu_info *ci, 64 void (*func)(void *), void *arg, 65 lwp_t **lp, const char *fmt, ...) 66{ 67 lwp_t *l; 68 vaddr_t uaddr; 69 int error, lc, lwp_flags; 70 va_list ap; 71 72 lwp_flags = LWP_DETACHED; 73 74 uaddr = uvm_uarea_alloc(); 75 if (uaddr == 0) { 76 return ENOMEM; 77 } 78 if ((flag & KTHREAD_TS) != 0) { 79 lc = SCHED_OTHER; 80 } else { 81 lc = SCHED_RR; 82 } 83 84 if ((flag & KTHREAD_JOINABLE) != 0) { 85 lwp_flags &= ~LWP_DETACHED; 86 } 87 88 error = lwp_create(&lwp0, &proc0, uaddr, lwp_flags, NULL, 89 0, func, arg, &l, lc); 90 if (error) { 91 uvm_uarea_free(uaddr); 92 return error; 93 } 94 if (fmt != NULL) { 95 l->l_name = kmem_alloc(MAXCOMLEN, KM_SLEEP); 96 if (l->l_name == NULL) { 97 kthread_destroy(l); 98 return ENOMEM; 99 } 100 va_start(ap, fmt); 101 vsnprintf(l->l_name, MAXCOMLEN, fmt, ap); 102 va_end(ap); 103 } 104 105 /* 106 * Set parameters. 107 */ 108 if ((flag & KTHREAD_INTR) != 0) { 109 KASSERT((flag & KTHREAD_MPSAFE) != 0); 110 } 111 112 /* Joinable kthread can't be NULL. */ 113 if ((flag & KTHREAD_JOINABLE) != 0) { 114 KASSERT(l != NULL); 115 } 116 117 if (pri == PRI_NONE) { 118 if ((flag & KTHREAD_TS) != 0) { 119 /* Maximum user priority level. */ 120 pri = MAXPRI_USER; 121 } else { 122 /* Minimum kernel priority level. */ 123 pri = PRI_KTHREAD; 124 } 125 } 126 mutex_enter(proc0.p_lock); 127 lwp_lock(l); 128 l->l_priority = pri; 129 if (ci != NULL) { 130 if (ci != l->l_cpu) { 131 lwp_unlock_to(l, ci->ci_schedstate.spc_mutex); 132 lwp_lock(l); 133 } 134 l->l_pflag |= LP_BOUND; 135 l->l_cpu = ci; 136 } 137 if ((flag & KTHREAD_INTR) != 0) 138 l->l_pflag |= LP_INTR; 139 if ((flag & KTHREAD_MPSAFE) == 0) 140 l->l_pflag &= ~LP_MPSAFE; 141 142 /* 143 * Set the new LWP running, unless the caller has requested 144 * otherwise. 145 */ 146 if ((flag & KTHREAD_IDLE) == 0) { 147 l->l_stat = LSRUN; 148 sched_enqueue(l, false); 149 lwp_unlock(l); 150 } else 151 lwp_unlock_to(l, ci->ci_schedstate.spc_lwplock); 152 153 /* 154 * The LWP is not created suspended or stopped and cannot be set 155 * into those states later, so must be considered runnable. 156 */ 157 proc0.p_nrlwps++; 158 mutex_exit(proc0.p_lock); 159 160 /* All done! */ 161 if (lp != NULL) 162 *lp = l; 163 164 return (0); 165} 166 167/* 168 * Cause a kernel thread to exit. Assumes the exiting thread is the 169 * current context. 170 */ 171void 172kthread_exit(int ecode) 173{ 174 const char *name; 175 lwp_t *l = curlwp; 176 177 /* We can't do much with the exit code, so just report it. */ 178 if (ecode != 0) { 179 if ((name = l->l_name) == NULL) 180 name = "unnamed"; 181 printf("WARNING: kthread `%s' (%d) exits with status %d\n", 182 name, l->l_lid, ecode); 183 } 184 185 /* And exit.. */ 186 lwp_exit(l); 187 188 /* 189 * XXX Fool the compiler. Making exit1() __noreturn__ is a can 190 * XXX of worms right now. 191 */ 192 for (;;) 193 ; 194} 195 196/* 197 * Destroy an inactive kthread. The kthread must be in the LSIDL state. 198 */ 199void 200kthread_destroy(lwp_t *l) 201{ 202 proc_t *p; 203 204 KASSERT((l->l_flag & LW_SYSTEM) != 0); 205 KASSERT(l->l_stat == LSIDL); 206 207 p = l->l_proc; 208 209 /* Add LRP_DETACHED flag because we can have joinable kthread now. */ 210 mutex_enter(p->p_lock); 211 l->l_prflag |= LPR_DETACHED; 212 mutex_exit(p->p_lock); 213 214 lwp_exit(l); 215} 216 217/* 218 * Wait for a kthread to exit, as pthread_join(). 219 */ 220int 221kthread_join(lwp_t *l) 222{ 223 lwpid_t departed; 224 proc_t *p; 225 int error; 226 227 KASSERT((l->l_flag & LW_SYSTEM) != 0); 228 KASSERT((l->l_prflag & LPR_DETACHED) == 0); 229 230 p = l->l_proc; 231 232 mutex_enter(p->p_lock); 233 error = lwp_wait1(curlwp, l->l_lid, &departed, LWPWAIT_EXITCONTROL); 234 mutex_exit(p->p_lock); 235 236 return error; 237} 238