1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/cpuset.h> 32 #include <sys/kthread.h> 33 #include <sys/lock.h> 34 #include <sys/mutex.h> 35 #include <sys/proc.h> 36 #include <sys/resourcevar.h> 37 #include <sys/rwlock.h> 38 #include <sys/signalvar.h> 39 #include <sys/sysent.h> 40 #include <sys/sx.h> 41 #include <sys/umtxvar.h> 42 #include <sys/unistd.h> 43 #include <sys/wait.h> 44 #include <sys/sched.h> 45 #include <sys/tslog.h> 46 #include <vm/vm.h> 47 #include <vm/vm_extern.h> 48 49 #include <machine/stdarg.h> 50 51 /* 52 * Start a kernel process. This is called after a fork() call in 53 * mi_startup() in the file kern/init_main.c. 54 * 55 * This function is used to start "internal" daemons and intended 56 * to be called from SYSINIT(). 57 */ 58 void 59 kproc_start(const void *udata) 60 { 61 const struct kproc_desc *kp = udata; 62 int error; 63 64 error = kproc_create((void (*)(void *))kp->func, NULL, 65 kp->global_procpp, 0, 0, "%s", kp->arg0); 66 if (error) 67 panic("kproc_start: %s: error %d", kp->arg0, error); 68 } 69 70 /* 71 * Create a kernel process/thread/whatever. It shares its address space 72 * with proc0 - ie: kernel only. 73 * 74 * func is the function to start. 75 * arg is the parameter to pass to function on first startup. 76 * newpp is the return value pointing to the thread's struct proc. 77 * flags are flags to fork1 (in unistd.h) 78 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.). 79 */ 80 static int 81 kproc_create1(void (*func)(void *), void *arg, 82 struct proc **newpp, int flags, int pages, const char *tdname) 83 { 84 struct fork_req fr; 85 int error; 86 struct thread *td; 87 struct proc *p2; 88 89 if (!proc0.p_stats) 90 panic("kproc_create called too soon"); 91 92 bzero(&fr, sizeof(fr)); 93 fr.fr_flags = RFMEM | RFFDG | RFPROC | RFSTOPPED | flags; 94 fr.fr_flags2 = FR2_KPROC; 95 fr.fr_pages = pages; 96 fr.fr_procp = &p2; 97 error = fork1(&thread0, &fr); 98 if (error != 0) 99 return (error); 100 101 /* save a global descriptor, if desired */ 102 if (newpp != NULL) 103 *newpp = p2; 104 105 /* set up arg0 for 'ps', et al */ 106 strcpy(p2->p_comm, tdname); 107 td = FIRST_THREAD_IN_PROC(p2); 108 strcpy(td->td_name, tdname); 109 #ifdef KTR 110 sched_clear_tdname(td); 111 #endif 112 TSTHREAD(td, td->td_name); 113 #ifdef HWPMC_HOOKS 114 if (PMC_SYSTEM_SAMPLING_ACTIVE()) { 115 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_PROC_CREATE_LOG, p2); 116 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL); 117 } 118 #endif 119 120 /* call the processes' main()... */ 121 cpu_fork_kthread_handler(td, func, arg); 122 123 /* Avoid inheriting affinity from a random parent. */ 124 cpuset_kernthread(td); 125 thread_lock(td); 126 TD_SET_CAN_RUN(td); 127 sched_prio(td, PVM); 128 sched_user_prio(td, PUSER); 129 130 /* Delay putting it on the run queue until now. */ 131 if ((flags & RFSTOPPED) == 0) 132 sched_add(td, SRQ_BORING); 133 else 134 thread_unlock(td); 135 136 return (0); 137 } 138 139 int 140 kproc_create(void (*func)(void *), void *arg, 141 struct proc **newpp, int flags, int pages, const char *fmt, ...) 142 { 143 va_list ap; 144 int error; 145 char tdname[MAXCOMLEN + 1]; 146 147 va_start(ap, fmt); 148 vsnprintf(tdname, sizeof(tdname), fmt, ap); 149 va_end(ap); 150 DROP_GIANT(); 151 error = kproc_create1(func, arg, newpp, flags, pages, tdname); 152 PICKUP_GIANT(); 153 return (error); 154 } 155 156 void 157 kproc_exit(int ecode) 158 { 159 struct thread *td; 160 struct proc *p; 161 162 td = curthread; 163 p = td->td_proc; 164 165 /* 166 * Reparent curthread from proc0 to init so that the zombie 167 * is harvested. 168 */ 169 sx_xlock(&proctree_lock); 170 PROC_LOCK(p); 171 proc_reparent(p, initproc, true); 172 PROC_UNLOCK(p); 173 sx_xunlock(&proctree_lock); 174 175 /* 176 * Wakeup anyone waiting for us to exit. 177 */ 178 wakeup(p); 179 180 /* Buh-bye! */ 181 exit1(td, ecode, 0); 182 } 183 184 /* 185 * Advise a kernel process to suspend (or resume) in its main loop. 186 * Participation is voluntary. 187 */ 188 int 189 kproc_suspend(struct proc *p, int timo) 190 { 191 /* 192 * Make sure this is indeed a system process and we can safely 193 * use the p_siglist field. 194 */ 195 PROC_LOCK(p); 196 if ((p->p_flag & P_KPROC) == 0) { 197 PROC_UNLOCK(p); 198 return (EINVAL); 199 } 200 SIGADDSET(p->p_siglist, SIGSTOP); 201 wakeup(p); 202 return (msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, 203 "suspkp", timo)); 204 } 205 206 int 207 kproc_resume(struct proc *p) 208 { 209 /* 210 * Make sure this is indeed a system process and we can safely 211 * use the p_siglist field. 212 */ 213 PROC_LOCK(p); 214 if ((p->p_flag & P_KPROC) == 0) { 215 PROC_UNLOCK(p); 216 return (EINVAL); 217 } 218 SIGDELSET(p->p_siglist, SIGSTOP); 219 PROC_UNLOCK(p); 220 wakeup(&p->p_siglist); 221 return (0); 222 } 223 224 void 225 kproc_suspend_check(struct proc *p) 226 { 227 PROC_LOCK(p); 228 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 229 wakeup(&p->p_siglist); 230 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0); 231 } 232 PROC_UNLOCK(p); 233 } 234 235 /* 236 * Start a kernel thread. 237 * 238 * This function is used to start "internal" daemons and intended 239 * to be called from SYSINIT(). 240 */ 241 242 void 243 kthread_start(const void *udata) 244 { 245 const struct kthread_desc *kp = udata; 246 int error; 247 248 error = kthread_add((void (*)(void *))kp->func, NULL, 249 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0); 250 if (error) 251 panic("kthread_start: %s: error %d", kp->arg0, error); 252 } 253 254 /* 255 * Create a kernel thread. It shares its address space 256 * with proc0 - ie: kernel only. 257 * 258 * func is the function to start. 259 * arg is the parameter to pass to function on first startup. 260 * newtdp is the return value pointing to the thread's struct thread. 261 * ** XXX fix this --> flags are flags to fork1 (in unistd.h) 262 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.). 263 */ 264 static int 265 kthread_add1(void (*func)(void *), void *arg, struct proc *p, 266 struct thread **newtdp, int flags, int pages, const char *tdname) 267 { 268 struct thread *newtd, *oldtd; 269 270 if (!proc0.p_stats) 271 panic("kthread_add called too soon"); 272 273 /* If no process supplied, put it on proc0 */ 274 if (p == NULL) 275 p = &proc0; 276 277 /* Initialize our new td */ 278 newtd = thread_alloc(pages); 279 if (newtd == NULL) 280 return (ENOMEM); 281 282 PROC_LOCK(p); 283 if (p->p_state == PRS_ZOMBIE || (p->p_flag2 & P2_WEXIT) != 0) { 284 PROC_UNLOCK(p); 285 return (ESRCH); 286 } 287 oldtd = FIRST_THREAD_IN_PROC(p); 288 289 bzero(&newtd->td_startzero, 290 __rangeof(struct thread, td_startzero, td_endzero)); 291 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy, 292 __rangeof(struct thread, td_startcopy, td_endcopy)); 293 294 /* set up arg0 for 'ps', et al */ 295 strcpy(newtd->td_name, tdname); 296 297 TSTHREAD(newtd, newtd->td_name); 298 299 newtd->td_proc = p; /* needed for cpu_copy_thread */ 300 newtd->td_pflags |= TDP_KTHREAD; 301 302 /* might be further optimized for kthread */ 303 cpu_copy_thread(newtd, oldtd); 304 305 /* put the designated function(arg) as the resume context */ 306 cpu_fork_kthread_handler(newtd, func, arg); 307 308 thread_cow_get_proc(newtd, p); 309 310 /* This code is similar to thread_create() in kern_thr.c. */ 311 p->p_flag |= P_HADTHREADS; 312 thread_link(newtd, p); 313 thread_lock(oldtd); 314 /* let the scheduler know about these things. */ 315 sched_fork_thread(oldtd, newtd); 316 TD_SET_CAN_RUN(newtd); 317 thread_unlock(oldtd); 318 PROC_UNLOCK(p); 319 320 tidhash_add(newtd); 321 322 /* Avoid inheriting affinity from a random parent. */ 323 cpuset_kernthread(newtd); 324 #ifdef HWPMC_HOOKS 325 if (PMC_SYSTEM_SAMPLING_ACTIVE()) 326 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL); 327 #endif 328 /* Delay putting it on the run queue until now. */ 329 if ((flags & RFSTOPPED) == 0) { 330 thread_lock(newtd); 331 sched_add(newtd, SRQ_BORING); 332 } 333 if (newtdp) 334 *newtdp = newtd; 335 return (0); 336 } 337 338 int 339 kthread_add(void (*func)(void *), void *arg, struct proc *p, 340 struct thread **newtdp, int flags, int pages, const char *fmt, ...) 341 { 342 va_list ap; 343 int error; 344 char tdname[MAXCOMLEN + 1]; 345 346 va_start(ap, fmt); 347 vsnprintf(tdname, sizeof(tdname), fmt, ap); 348 va_end(ap); 349 DROP_GIANT(); 350 error = kthread_add1(func, arg, p, newtdp, flags, pages, tdname); 351 PICKUP_GIANT(); 352 return (error); 353 } 354 355 void 356 kthread_exit(void) 357 { 358 struct proc *p; 359 struct thread *td; 360 361 td = curthread; 362 p = td->td_proc; 363 364 #ifdef HWPMC_HOOKS 365 if (PMC_SYSTEM_SAMPLING_ACTIVE()) 366 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT_LOG, NULL); 367 #endif 368 /* A module may be waiting for us to exit. */ 369 wakeup(td); 370 371 /* 372 * The last exiting thread in a kernel process must tear down 373 * the whole process. 374 */ 375 PROC_LOCK(p); 376 if (p->p_numthreads == 1) { 377 PROC_UNLOCK(p); 378 kproc_exit(0); 379 } 380 381 if (p->p_sysent->sv_ontdexit != NULL) 382 p->p_sysent->sv_ontdexit(td); 383 384 tidhash_remove(td); 385 umtx_thread_exit(td); 386 tdsigcleanup(td); 387 PROC_SLOCK(p); 388 thread_exit(); 389 } 390 391 /* 392 * Advise a kernel process to suspend (or resume) in its main loop. 393 * Participation is voluntary. 394 */ 395 int 396 kthread_suspend(struct thread *td, int timo) 397 { 398 struct proc *p; 399 400 p = td->td_proc; 401 402 /* 403 * td_pflags should not be read by any thread other than 404 * curthread, but as long as this flag is invariant during the 405 * thread's lifetime, it is OK to check its state. 406 */ 407 if ((td->td_pflags & TDP_KTHREAD) == 0) 408 return (EINVAL); 409 410 /* 411 * The caller of the primitive should have already checked that the 412 * thread is up and running, thus not being blocked by other 413 * conditions. 414 */ 415 PROC_LOCK(p); 416 thread_lock(td); 417 td->td_flags |= TDF_KTH_SUSP; 418 thread_unlock(td); 419 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt", 420 timo)); 421 } 422 423 /* 424 * Resume a thread previously put asleep with kthread_suspend(). 425 */ 426 int 427 kthread_resume(struct thread *td) 428 { 429 struct proc *p; 430 431 p = td->td_proc; 432 433 /* 434 * td_pflags should not be read by any thread other than 435 * curthread, but as long as this flag is invariant during the 436 * thread's lifetime, it is OK to check its state. 437 */ 438 if ((td->td_pflags & TDP_KTHREAD) == 0) 439 return (EINVAL); 440 441 PROC_LOCK(p); 442 thread_lock(td); 443 td->td_flags &= ~TDF_KTH_SUSP; 444 thread_unlock(td); 445 wakeup(&td->td_flags); 446 PROC_UNLOCK(p); 447 return (0); 448 } 449 450 /* 451 * Used by the thread to poll as to whether it should yield/sleep 452 * and notify the caller that is has happened. 453 */ 454 void 455 kthread_suspend_check(void) 456 { 457 struct proc *p; 458 struct thread *td; 459 460 td = curthread; 461 p = td->td_proc; 462 463 if ((td->td_pflags & TDP_KTHREAD) == 0) 464 panic("%s: curthread is not a valid kthread", __func__); 465 466 /* 467 * Setting the TDF_KTH_SUSP flag is protected by process lock. 468 * 469 * Do an unlocked read first to avoid serializing with all other threads 470 * in the common case of not suspending. 471 */ 472 if ((td->td_flags & TDF_KTH_SUSP) == 0) 473 return; 474 PROC_LOCK(p); 475 while ((td->td_flags & TDF_KTH_SUSP) != 0) { 476 wakeup(&td->td_flags); 477 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0); 478 } 479 PROC_UNLOCK(p); 480 } 481 482 int 483 kproc_kthread_add(void (*func)(void *), void *arg, 484 struct proc **procptr, struct thread **tdptr, 485 int flags, int pages, const char *procname, const char *fmt, ...) 486 { 487 int error; 488 va_list ap; 489 char buf[100]; 490 struct thread *td; 491 492 if (*procptr == NULL) { 493 error = kproc_create(func, arg, 494 procptr, flags, pages, "%s", procname); 495 if (error) 496 return (error); 497 td = FIRST_THREAD_IN_PROC(*procptr); 498 if (tdptr) 499 *tdptr = td; 500 va_start(ap, fmt); 501 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 502 va_end(ap); 503 #ifdef KTR 504 sched_clear_tdname(td); 505 #endif 506 return (0); 507 } 508 va_start(ap, fmt); 509 vsnprintf(buf, sizeof(buf), fmt, ap); 510 va_end(ap); 511 error = kthread_add(func, arg, *procptr, 512 tdptr, flags, pages, "%s", buf); 513 return (error); 514 } 515