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/umtx.h> 42 #include <sys/unistd.h> 43 #include <sys/wait.h> 44 #include <sys/sched.h> 45 #include <vm/vm.h> 46 #include <vm/vm_extern.h> 47 48 #include <machine/stdarg.h> 49 50 /* 51 * Start a kernel process. This is called after a fork() call in 52 * mi_startup() in the file kern/init_main.c. 53 * 54 * This function is used to start "internal" daemons and intended 55 * to be called from SYSINIT(). 56 */ 57 void 58 kproc_start(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 #ifdef KTR 119 sched_clear_tdname(td); 120 #endif 121 122 /* call the processes' main()... */ 123 cpu_set_fork_handler(td, func, arg); 124 125 /* Avoid inheriting affinity from a random parent. */ 126 cpuset_setthread(td->td_tid, cpuset_root); 127 thread_lock(td); 128 TD_SET_CAN_RUN(td); 129 sched_prio(td, PVM); 130 sched_user_prio(td, PUSER); 131 132 /* Delay putting it on the run queue until now. */ 133 if (!(flags & RFSTOPPED)) 134 sched_add(td, SRQ_BORING); 135 thread_unlock(td); 136 137 return 0; 138 } 139 140 void 141 kproc_exit(int ecode) 142 { 143 struct thread *td; 144 struct proc *p; 145 146 td = curthread; 147 p = td->td_proc; 148 149 /* 150 * Reparent curthread from proc0 to init so that the zombie 151 * is harvested. 152 */ 153 sx_xlock(&proctree_lock); 154 PROC_LOCK(p); 155 proc_reparent(p, initproc); 156 PROC_UNLOCK(p); 157 sx_xunlock(&proctree_lock); 158 159 /* 160 * Wakeup anyone waiting for us to exit. 161 */ 162 wakeup(p); 163 164 /* Buh-bye! */ 165 exit1(td, W_EXITCODE(ecode, 0)); 166 } 167 168 /* 169 * Advise a kernel process to suspend (or resume) in its main loop. 170 * Participation is voluntary. 171 */ 172 int 173 kproc_suspend(struct proc *p, int timo) 174 { 175 /* 176 * Make sure this is indeed a system process and we can safely 177 * use the p_siglist field. 178 */ 179 PROC_LOCK(p); 180 if ((p->p_flag & P_KTHREAD) == 0) { 181 PROC_UNLOCK(p); 182 return (EINVAL); 183 } 184 SIGADDSET(p->p_siglist, SIGSTOP); 185 wakeup(p); 186 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo); 187 } 188 189 int 190 kproc_resume(struct proc *p) 191 { 192 /* 193 * Make sure this is indeed a system process and we can safely 194 * use the p_siglist field. 195 */ 196 PROC_LOCK(p); 197 if ((p->p_flag & P_KTHREAD) == 0) { 198 PROC_UNLOCK(p); 199 return (EINVAL); 200 } 201 SIGDELSET(p->p_siglist, SIGSTOP); 202 PROC_UNLOCK(p); 203 wakeup(&p->p_siglist); 204 return (0); 205 } 206 207 void 208 kproc_suspend_check(struct proc *p) 209 { 210 PROC_LOCK(p); 211 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 212 wakeup(&p->p_siglist); 213 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0); 214 } 215 PROC_UNLOCK(p); 216 } 217 218 219 /* 220 * Start a kernel thread. 221 * 222 * This function is used to start "internal" daemons and intended 223 * to be called from SYSINIT(). 224 */ 225 226 void 227 kthread_start(const void *udata) 228 { 229 const struct kthread_desc *kp = udata; 230 int error; 231 232 error = kthread_add((void (*)(void *))kp->func, NULL, 233 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0); 234 if (error) 235 panic("kthread_start: %s: error %d", kp->arg0, error); 236 } 237 238 /* 239 * Create a kernel thread. It shares its address space 240 * with proc0 - ie: kernel only. 241 * 242 * func is the function to start. 243 * arg is the parameter to pass to function on first startup. 244 * newtdp is the return value pointing to the thread's struct thread. 245 * ** XXX fix this --> flags are flags to fork1 (in unistd.h) 246 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.). 247 */ 248 int 249 kthread_add(void (*func)(void *), void *arg, struct proc *p, 250 struct thread **newtdp, int flags, int pages, const char *fmt, ...) 251 { 252 va_list ap; 253 struct thread *newtd, *oldtd; 254 255 if (!proc0.p_stats) 256 panic("kthread_add called too soon"); 257 258 /* If no process supplied, put it on proc0 */ 259 if (p == NULL) 260 p = &proc0; 261 262 /* Initialize our new td */ 263 newtd = thread_alloc(pages); 264 if (newtd == NULL) 265 return (ENOMEM); 266 267 PROC_LOCK(p); 268 oldtd = FIRST_THREAD_IN_PROC(p); 269 270 bzero(&newtd->td_startzero, 271 __rangeof(struct thread, td_startzero, td_endzero)); 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 thread_cow_get_proc(newtd, p); 291 292 /* this code almost the same as create_thread() in kern_thr.c */ 293 p->p_flag |= P_HADTHREADS; 294 thread_link(newtd, p); 295 thread_lock(oldtd); 296 /* let the scheduler know about these things. */ 297 sched_fork_thread(oldtd, newtd); 298 TD_SET_CAN_RUN(newtd); 299 thread_unlock(oldtd); 300 PROC_UNLOCK(p); 301 302 tidhash_add(newtd); 303 304 /* Avoid inheriting affinity from a random parent. */ 305 cpuset_setthread(newtd->td_tid, cpuset_root); 306 307 /* Delay putting it on the run queue until now. */ 308 if (!(flags & RFSTOPPED)) { 309 thread_lock(newtd); 310 sched_add(newtd, SRQ_BORING); 311 thread_unlock(newtd); 312 } 313 if (newtdp) 314 *newtdp = newtd; 315 return 0; 316 } 317 318 void 319 kthread_exit(void) 320 { 321 struct proc *p; 322 323 p = curthread->td_proc; 324 325 /* A module may be waiting for us to exit. */ 326 wakeup(curthread); 327 328 /* 329 * The last exiting thread in a kernel process must tear down 330 * the whole process. 331 */ 332 rw_wlock(&tidhash_lock); 333 PROC_LOCK(p); 334 if (p->p_numthreads == 1) { 335 PROC_UNLOCK(p); 336 rw_wunlock(&tidhash_lock); 337 kproc_exit(0); 338 } 339 LIST_REMOVE(curthread, td_hash); 340 rw_wunlock(&tidhash_lock); 341 umtx_thread_exit(curthread); 342 PROC_SLOCK(p); 343 thread_exit(); 344 } 345 346 /* 347 * Advise a kernel process to suspend (or resume) in its main loop. 348 * Participation is voluntary. 349 */ 350 int 351 kthread_suspend(struct thread *td, int timo) 352 { 353 struct proc *p; 354 355 p = td->td_proc; 356 357 /* 358 * td_pflags should not be read by any thread other than 359 * curthread, but as long as this flag is invariant during the 360 * thread's lifetime, it is OK to check its state. 361 */ 362 if ((td->td_pflags & TDP_KTHREAD) == 0) 363 return (EINVAL); 364 365 /* 366 * The caller of the primitive should have already checked that the 367 * thread is up and running, thus not being blocked by other 368 * conditions. 369 */ 370 PROC_LOCK(p); 371 thread_lock(td); 372 td->td_flags |= TDF_KTH_SUSP; 373 thread_unlock(td); 374 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt", 375 timo)); 376 } 377 378 /* 379 * Resume a thread previously put asleep with kthread_suspend(). 380 */ 381 int 382 kthread_resume(struct thread *td) 383 { 384 struct proc *p; 385 386 p = td->td_proc; 387 388 /* 389 * td_pflags should not be read by any thread other than 390 * curthread, but as long as this flag is invariant during the 391 * thread's lifetime, it is OK to check its state. 392 */ 393 if ((td->td_pflags & TDP_KTHREAD) == 0) 394 return (EINVAL); 395 396 PROC_LOCK(p); 397 thread_lock(td); 398 td->td_flags &= ~TDF_KTH_SUSP; 399 thread_unlock(td); 400 wakeup(&td->td_flags); 401 PROC_UNLOCK(p); 402 return (0); 403 } 404 405 /* 406 * Used by the thread to poll as to whether it should yield/sleep 407 * and notify the caller that is has happened. 408 */ 409 void 410 kthread_suspend_check() 411 { 412 struct proc *p; 413 struct thread *td; 414 415 td = curthread; 416 p = td->td_proc; 417 418 if ((td->td_pflags & TDP_KTHREAD) == 0) 419 panic("%s: curthread is not a valid kthread", __func__); 420 421 /* 422 * As long as the double-lock protection is used when accessing the 423 * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex 424 * is fine. 425 */ 426 PROC_LOCK(p); 427 while (td->td_flags & TDF_KTH_SUSP) { 428 wakeup(&td->td_flags); 429 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0); 430 } 431 PROC_UNLOCK(p); 432 } 433 434 int 435 kproc_kthread_add(void (*func)(void *), void *arg, 436 struct proc **procptr, struct thread **tdptr, 437 int flags, int pages, const char *procname, const char *fmt, ...) 438 { 439 int error; 440 va_list ap; 441 char buf[100]; 442 struct thread *td; 443 444 if (*procptr == 0) { 445 error = kproc_create(func, arg, 446 procptr, flags, pages, "%s", procname); 447 if (error) 448 return (error); 449 td = FIRST_THREAD_IN_PROC(*procptr); 450 if (tdptr) 451 *tdptr = td; 452 va_start(ap, fmt); 453 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 454 va_end(ap); 455 #ifdef KTR 456 sched_clear_tdname(td); 457 #endif 458 return (0); 459 } 460 va_start(ap, fmt); 461 vsnprintf(buf, sizeof(buf), fmt, ap); 462 va_end(ap); 463 error = kthread_add(func, arg, *procptr, 464 tdptr, flags, pages, "%s", buf); 465 return (error); 466 } 467