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 /* 290 * Set the new thread pointer before the thread starts running: *newtdp 291 * could be a pointer that is referenced by "func". 292 */ 293 if (newtdp != NULL) 294 *newtdp = newtd; 295 296 bzero(&newtd->td_startzero, 297 __rangeof(struct thread, td_startzero, td_endzero)); 298 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy, 299 __rangeof(struct thread, td_startcopy, td_endcopy)); 300 301 /* set up arg0 for 'ps', et al */ 302 strcpy(newtd->td_name, tdname); 303 304 TSTHREAD(newtd, newtd->td_name); 305 306 newtd->td_proc = p; /* needed for cpu_copy_thread */ 307 newtd->td_pflags |= TDP_KTHREAD; 308 309 /* might be further optimized for kthread */ 310 cpu_copy_thread(newtd, oldtd); 311 312 /* put the designated function(arg) as the resume context */ 313 cpu_fork_kthread_handler(newtd, func, arg); 314 315 thread_cow_get_proc(newtd, p); 316 317 /* This code is similar to thread_create() in kern_thr.c. */ 318 p->p_flag |= P_HADTHREADS; 319 thread_link(newtd, p); 320 thread_lock(oldtd); 321 /* let the scheduler know about these things. */ 322 sched_fork_thread(oldtd, newtd); 323 TD_SET_CAN_RUN(newtd); 324 thread_unlock(oldtd); 325 PROC_UNLOCK(p); 326 327 tidhash_add(newtd); 328 329 /* Avoid inheriting affinity from a random parent. */ 330 cpuset_kernthread(newtd); 331 #ifdef HWPMC_HOOKS 332 if (PMC_SYSTEM_SAMPLING_ACTIVE()) 333 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL); 334 #endif 335 /* Delay putting it on the run queue until now. */ 336 if ((flags & RFSTOPPED) == 0) { 337 thread_lock(newtd); 338 sched_add(newtd, SRQ_BORING); 339 } 340 return (0); 341 } 342 343 int 344 kthread_add(void (*func)(void *), void *arg, struct proc *p, 345 struct thread **newtdp, int flags, int pages, const char *fmt, ...) 346 { 347 va_list ap; 348 int error; 349 char tdname[MAXCOMLEN + 1]; 350 351 va_start(ap, fmt); 352 vsnprintf(tdname, sizeof(tdname), fmt, ap); 353 va_end(ap); 354 DROP_GIANT(); 355 error = kthread_add1(func, arg, p, newtdp, flags, pages, tdname); 356 PICKUP_GIANT(); 357 return (error); 358 } 359 360 void 361 kthread_exit(void) 362 { 363 struct proc *p; 364 struct thread *td; 365 366 td = curthread; 367 p = td->td_proc; 368 369 #ifdef HWPMC_HOOKS 370 if (PMC_SYSTEM_SAMPLING_ACTIVE()) 371 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT_LOG, NULL); 372 #endif 373 /* A module may be waiting for us to exit. */ 374 wakeup(td); 375 376 /* 377 * The last exiting thread in a kernel process must tear down 378 * the whole process. 379 */ 380 PROC_LOCK(p); 381 if (p->p_numthreads == 1) { 382 PROC_UNLOCK(p); 383 kproc_exit(0); 384 } 385 386 if (p->p_sysent->sv_ontdexit != NULL) 387 p->p_sysent->sv_ontdexit(td); 388 389 tidhash_remove(td); 390 umtx_thread_exit(td); 391 tdsigcleanup(td); 392 PROC_SLOCK(p); 393 thread_exit(); 394 } 395 396 /* 397 * Advise a kernel process to suspend (or resume) in its main loop. 398 * Participation is voluntary. 399 */ 400 int 401 kthread_suspend(struct thread *td, int timo) 402 { 403 struct proc *p; 404 405 p = td->td_proc; 406 407 /* 408 * td_pflags should not be read by any thread other than 409 * curthread, but as long as this flag is invariant during the 410 * thread's lifetime, it is OK to check its state. 411 */ 412 if ((td->td_pflags & TDP_KTHREAD) == 0) 413 return (EINVAL); 414 415 /* 416 * The caller of the primitive should have already checked that the 417 * thread is up and running, thus not being blocked by other 418 * conditions. 419 */ 420 PROC_LOCK(p); 421 thread_lock(td); 422 td->td_flags |= TDF_KTH_SUSP; 423 thread_unlock(td); 424 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt", 425 timo)); 426 } 427 428 /* 429 * Resume a thread previously put asleep with kthread_suspend(). 430 */ 431 int 432 kthread_resume(struct thread *td) 433 { 434 struct proc *p; 435 436 p = td->td_proc; 437 438 /* 439 * td_pflags should not be read by any thread other than 440 * curthread, but as long as this flag is invariant during the 441 * thread's lifetime, it is OK to check its state. 442 */ 443 if ((td->td_pflags & TDP_KTHREAD) == 0) 444 return (EINVAL); 445 446 PROC_LOCK(p); 447 thread_lock(td); 448 td->td_flags &= ~TDF_KTH_SUSP; 449 thread_unlock(td); 450 wakeup(&td->td_flags); 451 PROC_UNLOCK(p); 452 return (0); 453 } 454 455 /* 456 * Used by the thread to poll as to whether it should yield/sleep 457 * and notify the caller that is has happened. 458 */ 459 void 460 kthread_suspend_check(void) 461 { 462 struct proc *p; 463 struct thread *td; 464 465 td = curthread; 466 p = td->td_proc; 467 468 if ((td->td_pflags & TDP_KTHREAD) == 0) 469 panic("%s: curthread is not a valid kthread", __func__); 470 471 /* 472 * Setting the TDF_KTH_SUSP flag is protected by process lock. 473 * 474 * Do an unlocked read first to avoid serializing with all other threads 475 * in the common case of not suspending. 476 */ 477 if ((td->td_flags & TDF_KTH_SUSP) == 0) 478 return; 479 PROC_LOCK(p); 480 while ((td->td_flags & TDF_KTH_SUSP) != 0) { 481 wakeup(&td->td_flags); 482 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0); 483 } 484 PROC_UNLOCK(p); 485 } 486 487 int 488 kproc_kthread_add(void (*func)(void *), void *arg, 489 struct proc **procptr, struct thread **tdptr, 490 int flags, int pages, const char *procname, const char *fmt, ...) 491 { 492 int error; 493 va_list ap; 494 char buf[100]; 495 struct thread *td; 496 497 if (*procptr == NULL) { 498 error = kproc_create(func, arg, 499 procptr, flags, pages, "%s", procname); 500 if (error) 501 return (error); 502 td = FIRST_THREAD_IN_PROC(*procptr); 503 if (tdptr) 504 *tdptr = td; 505 va_start(ap, fmt); 506 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 507 va_end(ap); 508 #ifdef KTR 509 sched_clear_tdname(td); 510 #endif 511 return (0); 512 } 513 va_start(ap, fmt); 514 vsnprintf(buf, sizeof(buf), fmt, ap); 515 va_end(ap); 516 error = kthread_add(func, arg, *procptr, 517 tdptr, flags, pages, "%s", buf); 518 return (error); 519 } 520