1 /* 2 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/sys/kern/kern_kthread.c,v 1.5.2.3 2001/12/25 01:51:14 dillon Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/proc.h> 32 #include <sys/kthread.h> 33 #include <sys/ptrace.h> 34 #include <sys/resourcevar.h> 35 #include <sys/signalvar.h> 36 #include <sys/unistd.h> 37 #include <sys/wait.h> 38 39 #include <machine/stdarg.h> 40 41 static struct lwkt_token kpsus_token = LWKT_TOKEN_INITIALIZER(kpsus_token); 42 43 44 /* 45 * Create a new lightweight kernel thread. 46 */ 47 static int 48 _kthread_create(void (*func)(void *), void *arg, 49 struct thread **tdp, int cpu, const char *fmt, __va_list ap) 50 { 51 thread_t td; 52 int flags = 0; 53 54 if (bootverbose) 55 atomic_set_int(&flags, TDF_VERBOSE); 56 57 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, cpu, flags); 58 if (tdp) 59 *tdp = td; 60 cpu_set_thread_handler(td, kthread_exit, func, arg); 61 62 /* 63 * Set up arg0 for 'ps' etc 64 */ 65 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 66 67 td->td_ucred = crhold(proc0.p_ucred); 68 69 /* 70 * Schedule the thread to run 71 */ 72 lwkt_schedule(td); 73 74 return 0; 75 } 76 77 /* 78 * Creates a lwkt. No CPU preference. 79 */ 80 int 81 kthread_create(void (*func)(void *), void *arg, 82 struct thread **tdp, const char *fmt, ...) 83 { 84 __va_list ap; 85 int ret; 86 87 __va_start(ap, fmt); 88 ret = _kthread_create(func, arg, tdp, -1, fmt, ap); 89 __va_end(ap); 90 91 return ret; 92 } 93 94 /* 95 * Creates a lwkt and schedule it to run in a specific CPU. 96 * 97 */ 98 int 99 kthread_create_cpu(void (*func)(void *), void *arg, 100 struct thread **tdp, int cpu, const char *fmt, ...) 101 { 102 __va_list ap; 103 int ret; 104 105 __va_start(ap, fmt); 106 ret = _kthread_create(func, arg, tdp, cpu, fmt, ap); 107 __va_end(ap); 108 109 return ret; 110 } 111 112 #if 0 113 /* 114 * Same as kthread_create() but you can specify a custom stack size. 115 */ 116 int 117 kthread_create_stk(void (*func)(void *), void *arg, 118 struct thread **tdp, int stksize, const char *fmt, ...) 119 { 120 thread_t td; 121 __va_list ap; 122 123 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE); 124 if (tdp) 125 *tdp = td; 126 cpu_set_thread_handler(td, kthread_exit, func, arg); 127 128 __va_start(ap, fmt); 129 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 130 __va_end(ap); 131 132 lwkt_schedule(td); 133 return 0; 134 } 135 #endif 136 137 /* 138 * Destroy an LWKT thread. Warning! This function is not called when 139 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 140 * uses a different reaping mechanism. 141 * 142 * XXX duplicates lwkt_exit() 143 */ 144 void 145 kthread_exit(void) 146 { 147 lwkt_exit(); 148 } 149 150 /* 151 * Start a kernel process. This is called after a fork() call in 152 * mi_startup() in the file kern/init_main.c. 153 * 154 * This function is used to start "internal" daemons and intended 155 * to be called from SYSINIT(). 156 * 157 * These threads are created MPSAFE. 158 */ 159 void 160 kproc_start(const void *udata) 161 { 162 const struct kproc_desc *kp = udata; 163 int error; 164 165 error = kthread_create((void (*)(void *))kp->func, NULL, 166 kp->global_threadpp, "%s", kp->arg0); 167 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 168 if (error) 169 panic("kproc_start: %s: error %d", kp->arg0, error); 170 } 171 172 /* 173 * Advise a kernel process to suspend (or resume) in its main loop. 174 * Participation is voluntary. 175 */ 176 int 177 suspend_kproc(struct thread *td, int timo) 178 { 179 if (td->td_proc == NULL) { 180 lwkt_gettoken(&kpsus_token); 181 /* request thread pause */ 182 atomic_set_int(&td->td_mpflags, TDF_MP_STOPREQ); 183 wakeup(td); 184 while (td->td_mpflags & TDF_MP_STOPREQ) { 185 int error = tsleep(td, 0, "suspkp", timo); 186 if (error == EWOULDBLOCK) 187 break; 188 } 189 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 190 lwkt_reltoken(&kpsus_token); 191 return(0); 192 } else { 193 return(EINVAL); /* not a kernel thread */ 194 } 195 } 196 197 void 198 kproc_suspend_loop(void) 199 { 200 struct thread *td = curthread; 201 202 if (td->td_mpflags & TDF_MP_STOPREQ) { 203 lwkt_gettoken(&kpsus_token); 204 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 205 while ((td->td_mpflags & TDF_MP_WAKEREQ) == 0) { 206 wakeup(td); 207 tsleep(td, 0, "kpsusp", 0); 208 } 209 atomic_clear_int(&td->td_mpflags, TDF_MP_WAKEREQ); 210 wakeup(td); 211 lwkt_reltoken(&kpsus_token); 212 } 213 } 214 215