1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/cpuset.h> 35 #include <sys/kthread.h> 36 #include <sys/lock.h> 37 #include <sys/mutex.h> 38 #include <sys/proc.h> 39 #include <sys/resourcevar.h> 40 #include <sys/rwlock.h> 41 #include <sys/signalvar.h> 42 #include <sys/sx.h> 43 #include <sys/umtx.h> 44 #include <sys/unistd.h> 45 #include <sys/wait.h> 46 #include <sys/sched.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_pages = pages; 97 fr.fr_procp = &p2; 98 error = fork1(&thread0, &fr); 99 if (error) 100 return error; 101 102 /* save a global descriptor, if desired */ 103 if (newpp != NULL) 104 *newpp = p2; 105 106 /* this is a non-swapped system process */ 107 PROC_LOCK(p2); 108 td = FIRST_THREAD_IN_PROC(p2); 109 p2->p_flag |= P_SYSTEM | P_KPROC; 110 td->td_pflags |= TDP_KTHREAD; 111 mtx_lock(&p2->p_sigacts->ps_mtx); 112 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT; 113 mtx_unlock(&p2->p_sigacts->ps_mtx); 114 PROC_UNLOCK(p2); 115 116 /* set up arg0 for 'ps', et al */ 117 va_start(ap, fmt); 118 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 119 va_end(ap); 120 /* set up arg0 for 'ps', et al */ 121 va_start(ap, fmt); 122 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 123 va_end(ap); 124 #ifdef KTR 125 sched_clear_tdname(td); 126 #endif 127 128 /* call the processes' main()... */ 129 cpu_fork_kthread_handler(td, func, arg); 130 131 /* Avoid inheriting affinity from a random parent. */ 132 cpuset_setthread(td->td_tid, cpuset_root); 133 thread_lock(td); 134 TD_SET_CAN_RUN(td); 135 sched_prio(td, PVM); 136 sched_user_prio(td, PUSER); 137 138 /* Delay putting it on the run queue until now. */ 139 if (!(flags & RFSTOPPED)) 140 sched_add(td, SRQ_BORING); 141 thread_unlock(td); 142 143 return 0; 144 } 145 146 void 147 kproc_exit(int ecode) 148 { 149 struct thread *td; 150 struct proc *p; 151 152 td = curthread; 153 p = td->td_proc; 154 155 /* 156 * Reparent curthread from proc0 to init so that the zombie 157 * is harvested. 158 */ 159 sx_xlock(&proctree_lock); 160 PROC_LOCK(p); 161 proc_reparent(p, initproc); 162 PROC_UNLOCK(p); 163 sx_xunlock(&proctree_lock); 164 165 /* 166 * Wakeup anyone waiting for us to exit. 167 */ 168 wakeup(p); 169 170 /* Buh-bye! */ 171 exit1(td, ecode, 0); 172 } 173 174 /* 175 * Advise a kernel process to suspend (or resume) in its main loop. 176 * Participation is voluntary. 177 */ 178 int 179 kproc_suspend(struct proc *p, int timo) 180 { 181 /* 182 * Make sure this is indeed a system process and we can safely 183 * use the p_siglist field. 184 */ 185 PROC_LOCK(p); 186 if ((p->p_flag & P_KPROC) == 0) { 187 PROC_UNLOCK(p); 188 return (EINVAL); 189 } 190 SIGADDSET(p->p_siglist, SIGSTOP); 191 wakeup(p); 192 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo); 193 } 194 195 int 196 kproc_resume(struct proc *p) 197 { 198 /* 199 * Make sure this is indeed a system process and we can safely 200 * use the p_siglist field. 201 */ 202 PROC_LOCK(p); 203 if ((p->p_flag & P_KPROC) == 0) { 204 PROC_UNLOCK(p); 205 return (EINVAL); 206 } 207 SIGDELSET(p->p_siglist, SIGSTOP); 208 PROC_UNLOCK(p); 209 wakeup(&p->p_siglist); 210 return (0); 211 } 212 213 void 214 kproc_suspend_check(struct proc *p) 215 { 216 PROC_LOCK(p); 217 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 218 wakeup(&p->p_siglist); 219 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0); 220 } 221 PROC_UNLOCK(p); 222 } 223 224 225 /* 226 * Start a kernel thread. 227 * 228 * This function is used to start "internal" daemons and intended 229 * to be called from SYSINIT(). 230 */ 231 232 void 233 kthread_start(const void *udata) 234 { 235 const struct kthread_desc *kp = udata; 236 int error; 237 238 error = kthread_add((void (*)(void *))kp->func, NULL, 239 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0); 240 if (error) 241 panic("kthread_start: %s: error %d", kp->arg0, error); 242 } 243 244 /* 245 * Create a kernel thread. It shares its address space 246 * with proc0 - ie: kernel only. 247 * 248 * func is the function to start. 249 * arg is the parameter to pass to function on first startup. 250 * newtdp is the return value pointing to the thread's struct thread. 251 * ** XXX fix this --> flags are flags to fork1 (in unistd.h) 252 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.). 253 */ 254 int 255 kthread_add(void (*func)(void *), void *arg, struct proc *p, 256 struct thread **newtdp, int flags, int pages, const char *fmt, ...) 257 { 258 va_list ap; 259 struct thread *newtd, *oldtd; 260 261 if (!proc0.p_stats) 262 panic("kthread_add called too soon"); 263 264 /* If no process supplied, put it on proc0 */ 265 if (p == NULL) 266 p = &proc0; 267 268 /* Initialize our new td */ 269 newtd = thread_alloc(pages); 270 if (newtd == NULL) 271 return (ENOMEM); 272 273 PROC_LOCK(p); 274 oldtd = FIRST_THREAD_IN_PROC(p); 275 276 bzero(&newtd->td_startzero, 277 __rangeof(struct thread, td_startzero, td_endzero)); 278 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy, 279 __rangeof(struct thread, td_startcopy, td_endcopy)); 280 281 /* set up arg0 for 'ps', et al */ 282 va_start(ap, fmt); 283 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap); 284 va_end(ap); 285 286 newtd->td_proc = p; /* needed for cpu_copy_thread */ 287 /* might be further optimized for kthread */ 288 cpu_copy_thread(newtd, oldtd); 289 /* put the designated function(arg) as the resume context */ 290 cpu_fork_kthread_handler(newtd, func, arg); 291 292 newtd->td_pflags |= TDP_KTHREAD; 293 thread_cow_get_proc(newtd, p); 294 295 /* this code almost the same as create_thread() in kern_thr.c */ 296 p->p_flag |= P_HADTHREADS; 297 thread_link(newtd, p); 298 thread_lock(oldtd); 299 /* let the scheduler know about these things. */ 300 sched_fork_thread(oldtd, newtd); 301 TD_SET_CAN_RUN(newtd); 302 thread_unlock(oldtd); 303 PROC_UNLOCK(p); 304 305 tidhash_add(newtd); 306 307 /* Avoid inheriting affinity from a random parent. */ 308 cpuset_setthread(newtd->td_tid, cpuset_root); 309 310 /* Delay putting it on the run queue until now. */ 311 if (!(flags & RFSTOPPED)) { 312 thread_lock(newtd); 313 sched_add(newtd, SRQ_BORING); 314 thread_unlock(newtd); 315 } 316 if (newtdp) 317 *newtdp = newtd; 318 return 0; 319 } 320 321 void 322 kthread_exit(void) 323 { 324 struct proc *p; 325 struct thread *td; 326 327 td = curthread; 328 p = td->td_proc; 329 330 /* A module may be waiting for us to exit. */ 331 wakeup(td); 332 333 /* 334 * The last exiting thread in a kernel process must tear down 335 * the whole process. 336 */ 337 rw_wlock(&tidhash_lock); 338 PROC_LOCK(p); 339 if (p->p_numthreads == 1) { 340 PROC_UNLOCK(p); 341 rw_wunlock(&tidhash_lock); 342 kproc_exit(0); 343 } 344 LIST_REMOVE(td, td_hash); 345 rw_wunlock(&tidhash_lock); 346 umtx_thread_exit(td); 347 tdsigcleanup(td); 348 PROC_SLOCK(p); 349 thread_exit(); 350 } 351 352 /* 353 * Advise a kernel process to suspend (or resume) in its main loop. 354 * Participation is voluntary. 355 */ 356 int 357 kthread_suspend(struct thread *td, int timo) 358 { 359 struct proc *p; 360 361 p = td->td_proc; 362 363 /* 364 * td_pflags should not be read by any thread other than 365 * curthread, but as long as this flag is invariant during the 366 * thread's lifetime, it is OK to check its state. 367 */ 368 if ((td->td_pflags & TDP_KTHREAD) == 0) 369 return (EINVAL); 370 371 /* 372 * The caller of the primitive should have already checked that the 373 * thread is up and running, thus not being blocked by other 374 * conditions. 375 */ 376 PROC_LOCK(p); 377 thread_lock(td); 378 td->td_flags |= TDF_KTH_SUSP; 379 thread_unlock(td); 380 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt", 381 timo)); 382 } 383 384 /* 385 * Resume a thread previously put asleep with kthread_suspend(). 386 */ 387 int 388 kthread_resume(struct thread *td) 389 { 390 struct proc *p; 391 392 p = td->td_proc; 393 394 /* 395 * td_pflags should not be read by any thread other than 396 * curthread, but as long as this flag is invariant during the 397 * thread's lifetime, it is OK to check its state. 398 */ 399 if ((td->td_pflags & TDP_KTHREAD) == 0) 400 return (EINVAL); 401 402 PROC_LOCK(p); 403 thread_lock(td); 404 td->td_flags &= ~TDF_KTH_SUSP; 405 thread_unlock(td); 406 wakeup(&td->td_flags); 407 PROC_UNLOCK(p); 408 return (0); 409 } 410 411 /* 412 * Used by the thread to poll as to whether it should yield/sleep 413 * and notify the caller that is has happened. 414 */ 415 void 416 kthread_suspend_check(void) 417 { 418 struct proc *p; 419 struct thread *td; 420 421 td = curthread; 422 p = td->td_proc; 423 424 if ((td->td_pflags & TDP_KTHREAD) == 0) 425 panic("%s: curthread is not a valid kthread", __func__); 426 427 /* 428 * As long as the double-lock protection is used when accessing the 429 * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex 430 * is fine. 431 */ 432 PROC_LOCK(p); 433 while (td->td_flags & TDF_KTH_SUSP) { 434 wakeup(&td->td_flags); 435 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0); 436 } 437 PROC_UNLOCK(p); 438 } 439 440 int 441 kproc_kthread_add(void (*func)(void *), void *arg, 442 struct proc **procptr, struct thread **tdptr, 443 int flags, int pages, const char *procname, const char *fmt, ...) 444 { 445 int error; 446 va_list ap; 447 char buf[100]; 448 struct thread *td; 449 450 if (*procptr == NULL) { 451 error = kproc_create(func, arg, 452 procptr, flags, pages, "%s", procname); 453 if (error) 454 return (error); 455 td = FIRST_THREAD_IN_PROC(*procptr); 456 if (tdptr) 457 *tdptr = td; 458 va_start(ap, fmt); 459 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 460 va_end(ap); 461 #ifdef KTR 462 sched_clear_tdname(td); 463 #endif 464 return (0); 465 } 466 va_start(ap, fmt); 467 vsnprintf(buf, sizeof(buf), fmt, ap); 468 va_end(ap); 469 error = kthread_add(func, arg, *procptr, 470 tdptr, flags, pages, "%s", buf); 471 return (error); 472 } 473