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