1 /* $NetBSD: kern_kthread.c,v 1.30 2010/06/13 04:13:31 yamt 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 1.30 2010/06/13 04:13:31 yamt 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 */ 62 int 63 kthread_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 mutex_exit(proc0.p_lock); 153 154 /* All done! */ 155 if (lp != NULL) 156 *lp = l; 157 158 return (0); 159 } 160 161 /* 162 * Cause a kernel thread to exit. Assumes the exiting thread is the 163 * current context. 164 */ 165 void 166 kthread_exit(int ecode) 167 { 168 const char *name; 169 lwp_t *l = curlwp; 170 171 /* We can't do much with the exit code, so just report it. */ 172 if (ecode != 0) { 173 if ((name = l->l_name) == NULL) 174 name = "unnamed"; 175 printf("WARNING: kthread `%s' (%d) exits with status %d\n", 176 name, l->l_lid, ecode); 177 } 178 179 /* And exit.. */ 180 lwp_exit(l); 181 182 /* 183 * XXX Fool the compiler. Making exit1() __noreturn__ is a can 184 * XXX of worms right now. 185 */ 186 for (;;) 187 ; 188 } 189 190 /* 191 * Destroy an inactive kthread. The kthread must be in the LSIDL state. 192 */ 193 void 194 kthread_destroy(lwp_t *l) 195 { 196 proc_t *p; 197 198 KASSERT((l->l_flag & LW_SYSTEM) != 0); 199 KASSERT(l->l_stat == LSIDL); 200 201 p = l->l_proc; 202 203 /* Add LRP_DETACHED flag because we can have joinable kthread now. */ 204 mutex_enter(p->p_lock); 205 l->l_prflag |= LPR_DETACHED; 206 mutex_exit(p->p_lock); 207 208 lwp_exit(l); 209 } 210 211 /* 212 * Wait for a kthread to exit, as pthread_join(). 213 */ 214 int 215 kthread_join(lwp_t *l) 216 { 217 lwpid_t departed; 218 proc_t *p; 219 int error; 220 221 KASSERT((l->l_flag & LW_SYSTEM) != 0); 222 KASSERT((l->l_prflag & LPR_DETACHED) == 0); 223 224 p = l->l_proc; 225 226 mutex_enter(p->p_lock); 227 error = lwp_wait1(curlwp, l->l_lid, &departed, LWPWAIT_EXITCONTROL); 228 mutex_exit(p->p_lock); 229 230 return error; 231 } 232