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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/cpuset.h> 33 #include <sys/kthread.h> 34 #include <sys/lock.h> 35 #include <sys/mutex.h> 36 #include <sys/proc.h> 37 #include <sys/resourcevar.h> 38 #include <sys/rwlock.h> 39 #include <sys/signalvar.h> 40 #include <sys/sx.h> 41 #include <sys/unistd.h> 42 #include <sys/wait.h> 43 #include <sys/sched.h> 44 #include <vm/vm.h> 45 #include <vm/vm_extern.h> 46 47 #include <machine/stdarg.h> 48 49 /* 50 * Start a kernel process. This is called after a fork() call in 51 * mi_startup() in the file kern/init_main.c. 52 * 53 * This function is used to start "internal" daemons and intended 54 * to be called from SYSINIT(). 55 */ 56 void 57 kproc_start(udata) 58 const void *udata; 59 { 60 const struct kproc_desc *kp = udata; 61 int error; 62 63 error = kproc_create((void (*)(void *))kp->func, NULL, 64 kp->global_procpp, 0, 0, "%s", kp->arg0); 65 if (error) 66 panic("kproc_start: %s: error %d", kp->arg0, error); 67 } 68 69 /* 70 * Create a kernel process/thread/whatever. It shares its address space 71 * with proc0 - ie: kernel only. 72 * 73 * func is the function to start. 74 * arg is the parameter to pass to function on first startup. 75 * newpp is the return value pointing to the thread's struct proc. 76 * flags are flags to fork1 (in unistd.h) 77 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.). 78 */ 79 int 80 kproc_create(void (*func)(void *), void *arg, 81 struct proc **newpp, int flags, int pages, const char *fmt, ...) 82 { 83 int error; 84 va_list ap; 85 struct thread *td; 86 struct proc *p2; 87 88 if (!proc0.p_stats) 89 panic("kproc_create called too soon"); 90 91 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags, 92 pages, &p2, NULL, 0); 93 if (error) 94 return error; 95 96 /* save a global descriptor, if desired */ 97 if (newpp != NULL) 98 *newpp = p2; 99 100 /* this is a non-swapped system process */ 101 PROC_LOCK(p2); 102 td = FIRST_THREAD_IN_PROC(p2); 103 p2->p_flag |= P_SYSTEM | P_KTHREAD; 104 td->td_pflags |= TDP_KTHREAD; 105 mtx_lock(&p2->p_sigacts->ps_mtx); 106 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT; 107 mtx_unlock(&p2->p_sigacts->ps_mtx); 108 PROC_UNLOCK(p2); 109 110 /* set up arg0 for 'ps', et al */ 111 va_start(ap, fmt); 112 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 113 va_end(ap); 114 /* set up arg0 for 'ps', et al */ 115 va_start(ap, fmt); 116 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 117 va_end(ap); 118 119 /* call the processes' main()... */ 120 cpu_set_fork_handler(td, func, arg); 121 122 /* Avoid inheriting affinity from a random parent. */ 123 cpuset_setthread(td->td_tid, cpuset_root); 124 thread_lock(td); 125 TD_SET_CAN_RUN(td); 126 sched_prio(td, PVM); 127 sched_user_prio(td, PUSER); 128 129 /* Delay putting it on the run queue until now. */ 130 if (!(flags & RFSTOPPED)) 131 sched_add(td, SRQ_BORING); 132 thread_unlock(td); 133 134 return 0; 135 } 136 137 void 138 kproc_exit(int ecode) 139 { 140 struct thread *td; 141 struct proc *p; 142 143 td = curthread; 144 p = td->td_proc; 145 146 /* 147 * Reparent curthread from proc0 to init so that the zombie 148 * is harvested. 149 */ 150 sx_xlock(&proctree_lock); 151 PROC_LOCK(p); 152 proc_reparent(p, initproc); 153 PROC_UNLOCK(p); 154 sx_xunlock(&proctree_lock); 155 156 /* 157 * Wakeup anyone waiting for us to exit. 158 */ 159 wakeup(p); 160 161 /* Buh-bye! */ 162 exit1(td, W_EXITCODE(ecode, 0)); 163 } 164 165 /* 166 * Advise a kernel process to suspend (or resume) in its main loop. 167 * Participation is voluntary. 168 */ 169 int 170 kproc_suspend(struct proc *p, int timo) 171 { 172 /* 173 * Make sure this is indeed a system process and we can safely 174 * use the p_siglist field. 175 */ 176 PROC_LOCK(p); 177 if ((p->p_flag & P_KTHREAD) == 0) { 178 PROC_UNLOCK(p); 179 return (EINVAL); 180 } 181 SIGADDSET(p->p_siglist, SIGSTOP); 182 wakeup(p); 183 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo); 184 } 185 186 int 187 kproc_resume(struct proc *p) 188 { 189 /* 190 * Make sure this is indeed a system process and we can safely 191 * use the p_siglist field. 192 */ 193 PROC_LOCK(p); 194 if ((p->p_flag & P_KTHREAD) == 0) { 195 PROC_UNLOCK(p); 196 return (EINVAL); 197 } 198 SIGDELSET(p->p_siglist, SIGSTOP); 199 PROC_UNLOCK(p); 200 wakeup(&p->p_siglist); 201 return (0); 202 } 203 204 void 205 kproc_suspend_check(struct proc *p) 206 { 207 PROC_LOCK(p); 208 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 209 wakeup(&p->p_siglist); 210 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0); 211 } 212 PROC_UNLOCK(p); 213 } 214 215 216 /* 217 * Start a kernel thread. 218 * 219 * This function is used to start "internal" daemons and intended 220 * to be called from SYSINIT(). 221 */ 222 223 void 224 kthread_start(udata) 225 const void *udata; 226 { 227 const struct kthread_desc *kp = udata; 228 int error; 229 230 error = kthread_add((void (*)(void *))kp->func, NULL, 231 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0); 232 if (error) 233 panic("kthread_start: %s: error %d", kp->arg0, error); 234 } 235 236 /* 237 * Create a kernel thread. It shares its address space 238 * with proc0 - ie: kernel only. 239 * 240 * func is the function to start. 241 * arg is the parameter to pass to function on first startup. 242 * newtdp is the return value pointing to the thread's struct thread. 243 * ** XXX fix this --> flags are flags to fork1 (in unistd.h) 244 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.). 245 */ 246 int 247 kthread_add(void (*func)(void *), void *arg, struct proc *p, 248 struct thread **newtdp, int flags, int pages, const char *fmt, ...) 249 { 250 va_list ap; 251 struct thread *newtd, *oldtd; 252 253 if (!proc0.p_stats) 254 panic("kthread_add called too soon"); 255 256 /* If no process supplied, put it on proc0 */ 257 if (p == NULL) { 258 p = &proc0; 259 oldtd = &thread0; 260 } else { 261 oldtd = FIRST_THREAD_IN_PROC(p); 262 } 263 264 /* Initialize our new td */ 265 newtd = thread_alloc(pages); 266 if (newtd == NULL) 267 return (ENOMEM); 268 269 bzero(&newtd->td_startzero, 270 __rangeof(struct thread, td_startzero, td_endzero)); 271 /* XXX check if we should zero. */ 272 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy, 273 __rangeof(struct thread, td_startcopy, td_endcopy)); 274 275 /* set up arg0 for 'ps', et al */ 276 va_start(ap, fmt); 277 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap); 278 va_end(ap); 279 280 newtd->td_proc = p; /* needed for cpu_set_upcall */ 281 282 /* XXX optimise this probably? */ 283 /* On x86 (and probably the others too) it is way too full of junk */ 284 /* Needs a better name */ 285 cpu_set_upcall(newtd, oldtd); 286 /* put the designated function(arg) as the resume context */ 287 cpu_set_fork_handler(newtd, func, arg); 288 289 newtd->td_pflags |= TDP_KTHREAD; 290 newtd->td_ucred = crhold(p->p_ucred); 291 292 /* this code almost the same as create_thread() in kern_thr.c */ 293 PROC_LOCK(p); 294 p->p_flag |= P_HADTHREADS; 295 newtd->td_sigmask = oldtd->td_sigmask; /* XXX dubious */ 296 thread_link(newtd, p); 297 thread_lock(oldtd); 298 /* let the scheduler know about these things. */ 299 sched_fork_thread(oldtd, newtd); 300 TD_SET_CAN_RUN(newtd); 301 thread_unlock(oldtd); 302 PROC_UNLOCK(p); 303 304 tidhash_add(newtd); 305 306 /* Avoid inheriting affinity from a random parent. */ 307 cpuset_setthread(newtd->td_tid, cpuset_root); 308 309 /* Delay putting it on the run queue until now. */ 310 if (!(flags & RFSTOPPED)) { 311 thread_lock(newtd); 312 sched_add(newtd, SRQ_BORING); 313 thread_unlock(newtd); 314 } 315 if (newtdp) 316 *newtdp = newtd; 317 return 0; 318 } 319 320 void 321 kthread_exit(void) 322 { 323 struct proc *p; 324 325 p = curthread->td_proc; 326 327 /* A module may be waiting for us to exit. */ 328 wakeup(curthread); 329 330 /* 331 * The last exiting thread in a kernel process must tear down 332 * the whole process. 333 */ 334 rw_wlock(&tidhash_lock); 335 PROC_LOCK(p); 336 if (p->p_numthreads == 1) { 337 PROC_UNLOCK(p); 338 rw_wunlock(&tidhash_lock); 339 kproc_exit(0); 340 } 341 LIST_REMOVE(curthread, td_hash); 342 rw_wunlock(&tidhash_lock); 343 PROC_SLOCK(p); 344 thread_exit(); 345 } 346 347 /* 348 * Advise a kernel process to suspend (or resume) in its main loop. 349 * Participation is voluntary. 350 */ 351 int 352 kthread_suspend(struct thread *td, int timo) 353 { 354 struct proc *p; 355 356 p = td->td_proc; 357 358 /* 359 * td_pflags should not be read by any thread other than 360 * curthread, but as long as this flag is invariant during the 361 * thread's lifetime, it is OK to check its state. 362 */ 363 if ((td->td_pflags & TDP_KTHREAD) == 0) 364 return (EINVAL); 365 366 /* 367 * The caller of the primitive should have already checked that the 368 * thread is up and running, thus not being blocked by other 369 * conditions. 370 */ 371 PROC_LOCK(p); 372 thread_lock(td); 373 td->td_flags |= TDF_KTH_SUSP; 374 thread_unlock(td); 375 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt", 376 timo)); 377 } 378 379 /* 380 * Resume a thread previously put asleep with kthread_suspend(). 381 */ 382 int 383 kthread_resume(struct thread *td) 384 { 385 struct proc *p; 386 387 p = td->td_proc; 388 389 /* 390 * td_pflags should not be read by any thread other than 391 * curthread, but as long as this flag is invariant during the 392 * thread's lifetime, it is OK to check its state. 393 */ 394 if ((td->td_pflags & TDP_KTHREAD) == 0) 395 return (EINVAL); 396 397 PROC_LOCK(p); 398 thread_lock(td); 399 td->td_flags &= ~TDF_KTH_SUSP; 400 thread_unlock(td); 401 wakeup(&td->td_flags); 402 PROC_UNLOCK(p); 403 return (0); 404 } 405 406 /* 407 * Used by the thread to poll as to whether it should yield/sleep 408 * and notify the caller that is has happened. 409 */ 410 void 411 kthread_suspend_check() 412 { 413 struct proc *p; 414 struct thread *td; 415 416 td = curthread; 417 p = td->td_proc; 418 419 if ((td->td_pflags & TDP_KTHREAD) == 0) 420 panic("%s: curthread is not a valid kthread", __func__); 421 422 /* 423 * As long as the double-lock protection is used when accessing the 424 * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex 425 * is fine. 426 */ 427 PROC_LOCK(p); 428 while (td->td_flags & TDF_KTH_SUSP) { 429 wakeup(&td->td_flags); 430 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0); 431 } 432 PROC_UNLOCK(p); 433 } 434 435 int 436 kproc_kthread_add(void (*func)(void *), void *arg, 437 struct proc **procptr, struct thread **tdptr, 438 int flags, int pages, const char *procname, const char *fmt, ...) 439 { 440 int error; 441 va_list ap; 442 char buf[100]; 443 struct thread *td; 444 445 if (*procptr == 0) { 446 error = kproc_create(func, arg, 447 procptr, flags, pages, "%s", procname); 448 if (error) 449 return (error); 450 td = FIRST_THREAD_IN_PROC(*procptr); 451 if (tdptr) 452 *tdptr = td; 453 va_start(ap, fmt); 454 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 455 va_end(ap); 456 return (0); 457 } 458 va_start(ap, fmt); 459 vsnprintf(buf, sizeof(buf), fmt, ap); 460 va_end(ap); 461 error = kthread_add(func, arg, *procptr, 462 tdptr, flags, pages, "%s", buf); 463 return (error); 464 } 465