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 int 82 kproc_create(void (*func)(void *), void *arg, 83 struct proc **newpp, int flags, int pages, const char *fmt, ...) 84 { 85 struct fork_req fr; 86 int error; 87 va_list ap; 88 struct thread *td; 89 struct proc *p2; 90 91 if (!proc0.p_stats) 92 panic("kproc_create called too soon"); 93 94 bzero(&fr, sizeof(fr)); 95 fr.fr_flags = RFMEM | RFFDG | RFPROC | RFSTOPPED | flags; 96 fr.fr_flags2 = FR2_KPROC; 97 fr.fr_pages = pages; 98 fr.fr_procp = &p2; 99 error = fork1(&thread0, &fr); 100 if (error) 101 return error; 102 103 /* save a global descriptor, if desired */ 104 if (newpp != NULL) 105 *newpp = p2; 106 107 /* set up arg0 for 'ps', et al */ 108 va_start(ap, fmt); 109 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 110 va_end(ap); 111 td = FIRST_THREAD_IN_PROC(p2); 112 va_start(ap, fmt); 113 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 114 va_end(ap); 115 #ifdef KTR 116 sched_clear_tdname(td); 117 #endif 118 TSTHREAD(td, td->td_name); 119 #ifdef HWPMC_HOOKS 120 if (PMC_SYSTEM_SAMPLING_ACTIVE()) { 121 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_PROC_CREATE_LOG, p2); 122 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL); 123 } 124 #endif 125 126 /* call the processes' main()... */ 127 cpu_fork_kthread_handler(td, func, arg); 128 129 /* Avoid inheriting affinity from a random parent. */ 130 cpuset_kernthread(td); 131 thread_lock(td); 132 TD_SET_CAN_RUN(td); 133 sched_prio(td, PVM); 134 sched_user_prio(td, PUSER); 135 136 /* Delay putting it on the run queue until now. */ 137 if (!(flags & RFSTOPPED)) 138 sched_add(td, SRQ_BORING); 139 else 140 thread_unlock(td); 141 142 return 0; 143 } 144 145 void 146 kproc_exit(int ecode) 147 { 148 struct thread *td; 149 struct proc *p; 150 151 td = curthread; 152 p = td->td_proc; 153 154 /* 155 * Reparent curthread from proc0 to init so that the zombie 156 * is harvested. 157 */ 158 sx_xlock(&proctree_lock); 159 PROC_LOCK(p); 160 proc_reparent(p, initproc, true); 161 PROC_UNLOCK(p); 162 sx_xunlock(&proctree_lock); 163 164 /* 165 * Wakeup anyone waiting for us to exit. 166 */ 167 wakeup(p); 168 169 /* Buh-bye! */ 170 exit1(td, ecode, 0); 171 } 172 173 /* 174 * Advise a kernel process to suspend (or resume) in its main loop. 175 * Participation is voluntary. 176 */ 177 int 178 kproc_suspend(struct proc *p, int timo) 179 { 180 /* 181 * Make sure this is indeed a system process and we can safely 182 * use the p_siglist field. 183 */ 184 PROC_LOCK(p); 185 if ((p->p_flag & P_KPROC) == 0) { 186 PROC_UNLOCK(p); 187 return (EINVAL); 188 } 189 SIGADDSET(p->p_siglist, SIGSTOP); 190 wakeup(p); 191 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo); 192 } 193 194 int 195 kproc_resume(struct proc *p) 196 { 197 /* 198 * Make sure this is indeed a system process and we can safely 199 * use the p_siglist field. 200 */ 201 PROC_LOCK(p); 202 if ((p->p_flag & P_KPROC) == 0) { 203 PROC_UNLOCK(p); 204 return (EINVAL); 205 } 206 SIGDELSET(p->p_siglist, SIGSTOP); 207 PROC_UNLOCK(p); 208 wakeup(&p->p_siglist); 209 return (0); 210 } 211 212 void 213 kproc_suspend_check(struct proc *p) 214 { 215 PROC_LOCK(p); 216 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 217 wakeup(&p->p_siglist); 218 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0); 219 } 220 PROC_UNLOCK(p); 221 } 222 223 /* 224 * Start a kernel thread. 225 * 226 * This function is used to start "internal" daemons and intended 227 * to be called from SYSINIT(). 228 */ 229 230 void 231 kthread_start(const void *udata) 232 { 233 const struct kthread_desc *kp = udata; 234 int error; 235 236 error = kthread_add((void (*)(void *))kp->func, NULL, 237 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0); 238 if (error) 239 panic("kthread_start: %s: error %d", kp->arg0, error); 240 } 241 242 /* 243 * Create a kernel thread. It shares its address space 244 * with proc0 - ie: kernel only. 245 * 246 * func is the function to start. 247 * arg is the parameter to pass to function on first startup. 248 * newtdp is the return value pointing to the thread's struct thread. 249 * ** XXX fix this --> flags are flags to fork1 (in unistd.h) 250 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.). 251 */ 252 int 253 kthread_add(void (*func)(void *), void *arg, struct proc *p, 254 struct thread **newtdp, int flags, int pages, const char *fmt, ...) 255 { 256 va_list ap; 257 struct thread *newtd, *oldtd; 258 259 if (!proc0.p_stats) 260 panic("kthread_add called too soon"); 261 262 /* If no process supplied, put it on proc0 */ 263 if (p == NULL) 264 p = &proc0; 265 266 /* Initialize our new td */ 267 newtd = thread_alloc(pages); 268 if (newtd == NULL) 269 return (ENOMEM); 270 271 PROC_LOCK(p); 272 oldtd = FIRST_THREAD_IN_PROC(p); 273 274 bzero(&newtd->td_startzero, 275 __rangeof(struct thread, td_startzero, td_endzero)); 276 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy, 277 __rangeof(struct thread, td_startcopy, td_endcopy)); 278 279 /* set up arg0 for 'ps', et al */ 280 va_start(ap, fmt); 281 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap); 282 va_end(ap); 283 284 TSTHREAD(newtd, newtd->td_name); 285 286 newtd->td_proc = p; /* needed for cpu_copy_thread */ 287 newtd->td_pflags |= TDP_KTHREAD; 288 289 /* might be further optimized for kthread */ 290 cpu_copy_thread(newtd, oldtd); 291 292 /* put the designated function(arg) as the resume context */ 293 cpu_fork_kthread_handler(newtd, func, arg); 294 295 thread_cow_get_proc(newtd, p); 296 297 /* This code is similar to thread_create() in kern_thr.c. */ 298 p->p_flag |= P_HADTHREADS; 299 thread_link(newtd, p); 300 thread_lock(oldtd); 301 /* let the scheduler know about these things. */ 302 sched_fork_thread(oldtd, newtd); 303 TD_SET_CAN_RUN(newtd); 304 thread_unlock(oldtd); 305 PROC_UNLOCK(p); 306 307 tidhash_add(newtd); 308 309 /* Avoid inheriting affinity from a random parent. */ 310 cpuset_kernthread(newtd); 311 #ifdef HWPMC_HOOKS 312 if (PMC_SYSTEM_SAMPLING_ACTIVE()) 313 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL); 314 #endif 315 /* Delay putting it on the run queue until now. */ 316 if (!(flags & RFSTOPPED)) { 317 thread_lock(newtd); 318 sched_add(newtd, SRQ_BORING); 319 } 320 if (newtdp) 321 *newtdp = newtd; 322 return 0; 323 } 324 325 void 326 kthread_exit(void) 327 { 328 struct proc *p; 329 struct thread *td; 330 331 td = curthread; 332 p = td->td_proc; 333 334 #ifdef HWPMC_HOOKS 335 if (PMC_SYSTEM_SAMPLING_ACTIVE()) 336 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT_LOG, NULL); 337 #endif 338 /* A module may be waiting for us to exit. */ 339 wakeup(td); 340 341 /* 342 * The last exiting thread in a kernel process must tear down 343 * the whole process. 344 */ 345 PROC_LOCK(p); 346 if (p->p_numthreads == 1) { 347 PROC_UNLOCK(p); 348 kproc_exit(0); 349 } 350 351 if (p->p_sysent->sv_ontdexit != NULL) 352 p->p_sysent->sv_ontdexit(td); 353 354 tidhash_remove(td); 355 umtx_thread_exit(td); 356 tdsigcleanup(td); 357 PROC_SLOCK(p); 358 thread_exit(); 359 } 360 361 /* 362 * Advise a kernel process to suspend (or resume) in its main loop. 363 * Participation is voluntary. 364 */ 365 int 366 kthread_suspend(struct thread *td, int timo) 367 { 368 struct proc *p; 369 370 p = td->td_proc; 371 372 /* 373 * td_pflags should not be read by any thread other than 374 * curthread, but as long as this flag is invariant during the 375 * thread's lifetime, it is OK to check its state. 376 */ 377 if ((td->td_pflags & TDP_KTHREAD) == 0) 378 return (EINVAL); 379 380 /* 381 * The caller of the primitive should have already checked that the 382 * thread is up and running, thus not being blocked by other 383 * conditions. 384 */ 385 PROC_LOCK(p); 386 thread_lock(td); 387 td->td_flags |= TDF_KTH_SUSP; 388 thread_unlock(td); 389 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt", 390 timo)); 391 } 392 393 /* 394 * Resume a thread previously put asleep with kthread_suspend(). 395 */ 396 int 397 kthread_resume(struct thread *td) 398 { 399 struct proc *p; 400 401 p = td->td_proc; 402 403 /* 404 * td_pflags should not be read by any thread other than 405 * curthread, but as long as this flag is invariant during the 406 * thread's lifetime, it is OK to check its state. 407 */ 408 if ((td->td_pflags & TDP_KTHREAD) == 0) 409 return (EINVAL); 410 411 PROC_LOCK(p); 412 thread_lock(td); 413 td->td_flags &= ~TDF_KTH_SUSP; 414 thread_unlock(td); 415 wakeup(&td->td_flags); 416 PROC_UNLOCK(p); 417 return (0); 418 } 419 420 /* 421 * Used by the thread to poll as to whether it should yield/sleep 422 * and notify the caller that is has happened. 423 */ 424 void 425 kthread_suspend_check(void) 426 { 427 struct proc *p; 428 struct thread *td; 429 430 td = curthread; 431 p = td->td_proc; 432 433 if ((td->td_pflags & TDP_KTHREAD) == 0) 434 panic("%s: curthread is not a valid kthread", __func__); 435 436 /* 437 * Setting the TDF_KTH_SUSP flag is protected by process lock. 438 * 439 * Do an unlocked read first to avoid serializing with all other threads 440 * in the common case of not suspending. 441 */ 442 if ((td->td_flags & TDF_KTH_SUSP) == 0) 443 return; 444 PROC_LOCK(p); 445 while ((td->td_flags & TDF_KTH_SUSP) != 0) { 446 wakeup(&td->td_flags); 447 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0); 448 } 449 PROC_UNLOCK(p); 450 } 451 452 int 453 kproc_kthread_add(void (*func)(void *), void *arg, 454 struct proc **procptr, struct thread **tdptr, 455 int flags, int pages, const char *procname, const char *fmt, ...) 456 { 457 int error; 458 va_list ap; 459 char buf[100]; 460 struct thread *td; 461 462 if (*procptr == NULL) { 463 error = kproc_create(func, arg, 464 procptr, flags, pages, "%s", procname); 465 if (error) 466 return (error); 467 td = FIRST_THREAD_IN_PROC(*procptr); 468 if (tdptr) 469 *tdptr = td; 470 va_start(ap, fmt); 471 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 472 va_end(ap); 473 #ifdef KTR 474 sched_clear_tdname(td); 475 #endif 476 return (0); 477 } 478 va_start(ap, fmt); 479 vsnprintf(buf, sizeof(buf), fmt, ap); 480 va_end(ap); 481 error = kthread_add(func, arg, *procptr, 482 tdptr, flags, pages, "%s", buf); 483 return (error); 484 } 485