1 /* 2 * linux/kernel/posix-timers.c 3 * 4 * 5 * 2002-10-15 Posix Clocks & timers 6 * by George Anzinger george@mvista.com 7 * 8 * Copyright (C) 2002 2003 by MontaVista Software. 9 * 10 * 2004-06-01 Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug. 11 * Copyright (C) 2004 Boris Hu 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License as published by 15 * the Free Software Foundation; either version 2 of the License, or (at 16 * your option) any later version. 17 * 18 * This program is distributed in the hope that it will be useful, but 19 * WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 21 * General Public License for more details. 22 23 * You should have received a copy of the GNU General Public License 24 * along with this program; if not, write to the Free Software 25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 26 * 27 * MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA 28 */ 29 30 /* These are all the functions necessary to implement 31 * POSIX clocks & timers 32 */ 33 #include <linux/mm.h> 34 #include <linux/interrupt.h> 35 #include <linux/slab.h> 36 #include <linux/time.h> 37 #include <linux/mutex.h> 38 39 #include <asm/uaccess.h> 40 #include <linux/list.h> 41 #include <linux/init.h> 42 #include <linux/compiler.h> 43 #include <linux/hash.h> 44 #include <linux/posix-clock.h> 45 #include <linux/posix-timers.h> 46 #include <linux/syscalls.h> 47 #include <linux/wait.h> 48 #include <linux/workqueue.h> 49 #include <linux/export.h> 50 #include <linux/hashtable.h> 51 52 #include "timekeeping.h" 53 54 /* 55 * Management arrays for POSIX timers. Timers are now kept in static hash table 56 * with 512 entries. 57 * Timer ids are allocated by local routine, which selects proper hash head by 58 * key, constructed from current->signal address and per signal struct counter. 59 * This keeps timer ids unique per process, but now they can intersect between 60 * processes. 61 */ 62 63 /* 64 * Lets keep our timers in a slab cache :-) 65 */ 66 static struct kmem_cache *posix_timers_cache; 67 68 static DEFINE_HASHTABLE(posix_timers_hashtable, 9); 69 static DEFINE_SPINLOCK(hash_lock); 70 71 /* 72 * we assume that the new SIGEV_THREAD_ID shares no bits with the other 73 * SIGEV values. Here we put out an error if this assumption fails. 74 */ 75 #if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \ 76 ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD)) 77 #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!" 78 #endif 79 80 /* 81 * parisc wants ENOTSUP instead of EOPNOTSUPP 82 */ 83 #ifndef ENOTSUP 84 # define ENANOSLEEP_NOTSUP EOPNOTSUPP 85 #else 86 # define ENANOSLEEP_NOTSUP ENOTSUP 87 #endif 88 89 /* 90 * The timer ID is turned into a timer address by idr_find(). 91 * Verifying a valid ID consists of: 92 * 93 * a) checking that idr_find() returns other than -1. 94 * b) checking that the timer id matches the one in the timer itself. 95 * c) that the timer owner is in the callers thread group. 96 */ 97 98 /* 99 * CLOCKs: The POSIX standard calls for a couple of clocks and allows us 100 * to implement others. This structure defines the various 101 * clocks. 102 * 103 * RESOLUTION: Clock resolution is used to round up timer and interval 104 * times, NOT to report clock times, which are reported with as 105 * much resolution as the system can muster. In some cases this 106 * resolution may depend on the underlying clock hardware and 107 * may not be quantifiable until run time, and only then is the 108 * necessary code is written. The standard says we should say 109 * something about this issue in the documentation... 110 * 111 * FUNCTIONS: The CLOCKs structure defines possible functions to 112 * handle various clock functions. 113 * 114 * The standard POSIX timer management code assumes the 115 * following: 1.) The k_itimer struct (sched.h) is used for 116 * the timer. 2.) The list, it_lock, it_clock, it_id and 117 * it_pid fields are not modified by timer code. 118 * 119 * Permissions: It is assumed that the clock_settime() function defined 120 * for each clock will take care of permission checks. Some 121 * clocks may be set able by any user (i.e. local process 122 * clocks) others not. Currently the only set able clock we 123 * have is CLOCK_REALTIME and its high res counter part, both of 124 * which we beg off on and pass to do_sys_settimeofday(). 125 */ 126 127 static struct k_clock posix_clocks[MAX_CLOCKS]; 128 129 /* 130 * These ones are defined below. 131 */ 132 static int common_nsleep(const clockid_t, int flags, struct timespec *t, 133 struct timespec __user *rmtp); 134 static int common_timer_create(struct k_itimer *new_timer); 135 static void common_timer_get(struct k_itimer *, struct itimerspec *); 136 static int common_timer_set(struct k_itimer *, int, 137 struct itimerspec *, struct itimerspec *); 138 static int common_timer_del(struct k_itimer *timer); 139 140 static enum hrtimer_restart posix_timer_fn(struct hrtimer *data); 141 142 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags); 143 144 #define lock_timer(tid, flags) \ 145 ({ struct k_itimer *__timr; \ 146 __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags)); \ 147 __timr; \ 148 }) 149 150 static int hash(struct signal_struct *sig, unsigned int nr) 151 { 152 return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable)); 153 } 154 155 static struct k_itimer *__posix_timers_find(struct hlist_head *head, 156 struct signal_struct *sig, 157 timer_t id) 158 { 159 struct k_itimer *timer; 160 161 hlist_for_each_entry_rcu(timer, head, t_hash) { 162 if ((timer->it_signal == sig) && (timer->it_id == id)) 163 return timer; 164 } 165 return NULL; 166 } 167 168 static struct k_itimer *posix_timer_by_id(timer_t id) 169 { 170 struct signal_struct *sig = current->signal; 171 struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)]; 172 173 return __posix_timers_find(head, sig, id); 174 } 175 176 static int posix_timer_add(struct k_itimer *timer) 177 { 178 struct signal_struct *sig = current->signal; 179 int first_free_id = sig->posix_timer_id; 180 struct hlist_head *head; 181 int ret = -ENOENT; 182 183 do { 184 spin_lock(&hash_lock); 185 head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)]; 186 if (!__posix_timers_find(head, sig, sig->posix_timer_id)) { 187 hlist_add_head_rcu(&timer->t_hash, head); 188 ret = sig->posix_timer_id; 189 } 190 if (++sig->posix_timer_id < 0) 191 sig->posix_timer_id = 0; 192 if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT)) 193 /* Loop over all possible ids completed */ 194 ret = -EAGAIN; 195 spin_unlock(&hash_lock); 196 } while (ret == -ENOENT); 197 return ret; 198 } 199 200 static inline void unlock_timer(struct k_itimer *timr, unsigned long flags) 201 { 202 spin_unlock_irqrestore(&timr->it_lock, flags); 203 } 204 205 /* Get clock_realtime */ 206 static int posix_clock_realtime_get(clockid_t which_clock, struct timespec *tp) 207 { 208 ktime_get_real_ts(tp); 209 return 0; 210 } 211 212 /* Set clock_realtime */ 213 static int posix_clock_realtime_set(const clockid_t which_clock, 214 const struct timespec *tp) 215 { 216 return do_sys_settimeofday(tp, NULL); 217 } 218 219 static int posix_clock_realtime_adj(const clockid_t which_clock, 220 struct timex *t) 221 { 222 return do_adjtimex(t); 223 } 224 225 /* 226 * Get monotonic time for posix timers 227 */ 228 static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp) 229 { 230 ktime_get_ts(tp); 231 return 0; 232 } 233 234 /* 235 * Get monotonic-raw time for posix timers 236 */ 237 static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp) 238 { 239 getrawmonotonic(tp); 240 return 0; 241 } 242 243 244 static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp) 245 { 246 *tp = current_kernel_time(); 247 return 0; 248 } 249 250 static int posix_get_monotonic_coarse(clockid_t which_clock, 251 struct timespec *tp) 252 { 253 *tp = get_monotonic_coarse(); 254 return 0; 255 } 256 257 static int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp) 258 { 259 *tp = ktime_to_timespec(KTIME_LOW_RES); 260 return 0; 261 } 262 263 static int posix_get_boottime(const clockid_t which_clock, struct timespec *tp) 264 { 265 get_monotonic_boottime(tp); 266 return 0; 267 } 268 269 static int posix_get_tai(clockid_t which_clock, struct timespec *tp) 270 { 271 timekeeping_clocktai(tp); 272 return 0; 273 } 274 275 /* 276 * Initialize everything, well, just everything in Posix clocks/timers ;) 277 */ 278 static __init int init_posix_timers(void) 279 { 280 struct k_clock clock_realtime = { 281 .clock_getres = hrtimer_get_res, 282 .clock_get = posix_clock_realtime_get, 283 .clock_set = posix_clock_realtime_set, 284 .clock_adj = posix_clock_realtime_adj, 285 .nsleep = common_nsleep, 286 .nsleep_restart = hrtimer_nanosleep_restart, 287 .timer_create = common_timer_create, 288 .timer_set = common_timer_set, 289 .timer_get = common_timer_get, 290 .timer_del = common_timer_del, 291 }; 292 struct k_clock clock_monotonic = { 293 .clock_getres = hrtimer_get_res, 294 .clock_get = posix_ktime_get_ts, 295 .nsleep = common_nsleep, 296 .nsleep_restart = hrtimer_nanosleep_restart, 297 .timer_create = common_timer_create, 298 .timer_set = common_timer_set, 299 .timer_get = common_timer_get, 300 .timer_del = common_timer_del, 301 }; 302 struct k_clock clock_monotonic_raw = { 303 .clock_getres = hrtimer_get_res, 304 .clock_get = posix_get_monotonic_raw, 305 }; 306 struct k_clock clock_realtime_coarse = { 307 .clock_getres = posix_get_coarse_res, 308 .clock_get = posix_get_realtime_coarse, 309 }; 310 struct k_clock clock_monotonic_coarse = { 311 .clock_getres = posix_get_coarse_res, 312 .clock_get = posix_get_monotonic_coarse, 313 }; 314 struct k_clock clock_tai = { 315 .clock_getres = hrtimer_get_res, 316 .clock_get = posix_get_tai, 317 .nsleep = common_nsleep, 318 .nsleep_restart = hrtimer_nanosleep_restart, 319 .timer_create = common_timer_create, 320 .timer_set = common_timer_set, 321 .timer_get = common_timer_get, 322 .timer_del = common_timer_del, 323 }; 324 struct k_clock clock_boottime = { 325 .clock_getres = hrtimer_get_res, 326 .clock_get = posix_get_boottime, 327 .nsleep = common_nsleep, 328 .nsleep_restart = hrtimer_nanosleep_restart, 329 .timer_create = common_timer_create, 330 .timer_set = common_timer_set, 331 .timer_get = common_timer_get, 332 .timer_del = common_timer_del, 333 }; 334 335 posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime); 336 posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic); 337 posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw); 338 posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse); 339 posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse); 340 posix_timers_register_clock(CLOCK_BOOTTIME, &clock_boottime); 341 posix_timers_register_clock(CLOCK_TAI, &clock_tai); 342 343 posix_timers_cache = kmem_cache_create("posix_timers_cache", 344 sizeof (struct k_itimer), 0, SLAB_PANIC, 345 NULL); 346 return 0; 347 } 348 349 __initcall(init_posix_timers); 350 351 static void schedule_next_timer(struct k_itimer *timr) 352 { 353 struct hrtimer *timer = &timr->it.real.timer; 354 355 if (timr->it.real.interval.tv64 == 0) 356 return; 357 358 timr->it_overrun += (unsigned int) hrtimer_forward(timer, 359 timer->base->get_time(), 360 timr->it.real.interval); 361 362 timr->it_overrun_last = timr->it_overrun; 363 timr->it_overrun = -1; 364 ++timr->it_requeue_pending; 365 hrtimer_restart(timer); 366 } 367 368 /* 369 * This function is exported for use by the signal deliver code. It is 370 * called just prior to the info block being released and passes that 371 * block to us. It's function is to update the overrun entry AND to 372 * restart the timer. It should only be called if the timer is to be 373 * restarted (i.e. we have flagged this in the sys_private entry of the 374 * info block). 375 * 376 * To protect against the timer going away while the interrupt is queued, 377 * we require that the it_requeue_pending flag be set. 378 */ 379 void do_schedule_next_timer(struct siginfo *info) 380 { 381 struct k_itimer *timr; 382 unsigned long flags; 383 384 timr = lock_timer(info->si_tid, &flags); 385 386 if (timr && timr->it_requeue_pending == info->si_sys_private) { 387 if (timr->it_clock < 0) 388 posix_cpu_timer_schedule(timr); 389 else 390 schedule_next_timer(timr); 391 392 info->si_overrun += timr->it_overrun_last; 393 } 394 395 if (timr) 396 unlock_timer(timr, flags); 397 } 398 399 int posix_timer_event(struct k_itimer *timr, int si_private) 400 { 401 struct task_struct *task; 402 int shared, ret = -1; 403 /* 404 * FIXME: if ->sigq is queued we can race with 405 * dequeue_signal()->do_schedule_next_timer(). 406 * 407 * If dequeue_signal() sees the "right" value of 408 * si_sys_private it calls do_schedule_next_timer(). 409 * We re-queue ->sigq and drop ->it_lock(). 410 * do_schedule_next_timer() locks the timer 411 * and re-schedules it while ->sigq is pending. 412 * Not really bad, but not that we want. 413 */ 414 timr->sigq->info.si_sys_private = si_private; 415 416 rcu_read_lock(); 417 task = pid_task(timr->it_pid, PIDTYPE_PID); 418 if (task) { 419 shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID); 420 ret = send_sigqueue(timr->sigq, task, shared); 421 } 422 rcu_read_unlock(); 423 /* If we failed to send the signal the timer stops. */ 424 return ret > 0; 425 } 426 EXPORT_SYMBOL_GPL(posix_timer_event); 427 428 /* 429 * This function gets called when a POSIX.1b interval timer expires. It 430 * is used as a callback from the kernel internal timer. The 431 * run_timer_list code ALWAYS calls with interrupts on. 432 433 * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers. 434 */ 435 static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer) 436 { 437 struct k_itimer *timr; 438 unsigned long flags; 439 int si_private = 0; 440 enum hrtimer_restart ret = HRTIMER_NORESTART; 441 442 timr = container_of(timer, struct k_itimer, it.real.timer); 443 spin_lock_irqsave(&timr->it_lock, flags); 444 445 if (timr->it.real.interval.tv64 != 0) 446 si_private = ++timr->it_requeue_pending; 447 448 if (posix_timer_event(timr, si_private)) { 449 /* 450 * signal was not sent because of sig_ignor 451 * we will not get a call back to restart it AND 452 * it should be restarted. 453 */ 454 if (timr->it.real.interval.tv64 != 0) { 455 ktime_t now = hrtimer_cb_get_time(timer); 456 457 /* 458 * FIXME: What we really want, is to stop this 459 * timer completely and restart it in case the 460 * SIG_IGN is removed. This is a non trivial 461 * change which involves sighand locking 462 * (sigh !), which we don't want to do late in 463 * the release cycle. 464 * 465 * For now we just let timers with an interval 466 * less than a jiffie expire every jiffie to 467 * avoid softirq starvation in case of SIG_IGN 468 * and a very small interval, which would put 469 * the timer right back on the softirq pending 470 * list. By moving now ahead of time we trick 471 * hrtimer_forward() to expire the timer 472 * later, while we still maintain the overrun 473 * accuracy, but have some inconsistency in 474 * the timer_gettime() case. This is at least 475 * better than a starved softirq. A more 476 * complex fix which solves also another related 477 * inconsistency is already in the pipeline. 478 */ 479 #ifdef CONFIG_HIGH_RES_TIMERS 480 { 481 ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ); 482 483 if (timr->it.real.interval.tv64 < kj.tv64) 484 now = ktime_add(now, kj); 485 } 486 #endif 487 timr->it_overrun += (unsigned int) 488 hrtimer_forward(timer, now, 489 timr->it.real.interval); 490 ret = HRTIMER_RESTART; 491 ++timr->it_requeue_pending; 492 } 493 } 494 495 unlock_timer(timr, flags); 496 return ret; 497 } 498 499 static struct pid *good_sigevent(sigevent_t * event) 500 { 501 struct task_struct *rtn = current->group_leader; 502 503 if ((event->sigev_notify & SIGEV_THREAD_ID ) && 504 (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) || 505 !same_thread_group(rtn, current) || 506 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL)) 507 return NULL; 508 509 if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) && 510 ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX))) 511 return NULL; 512 513 return task_pid(rtn); 514 } 515 516 void posix_timers_register_clock(const clockid_t clock_id, 517 struct k_clock *new_clock) 518 { 519 if ((unsigned) clock_id >= MAX_CLOCKS) { 520 printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n", 521 clock_id); 522 return; 523 } 524 525 if (!new_clock->clock_get) { 526 printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n", 527 clock_id); 528 return; 529 } 530 if (!new_clock->clock_getres) { 531 printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n", 532 clock_id); 533 return; 534 } 535 536 posix_clocks[clock_id] = *new_clock; 537 } 538 EXPORT_SYMBOL_GPL(posix_timers_register_clock); 539 540 static struct k_itimer * alloc_posix_timer(void) 541 { 542 struct k_itimer *tmr; 543 tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL); 544 if (!tmr) 545 return tmr; 546 if (unlikely(!(tmr->sigq = sigqueue_alloc()))) { 547 kmem_cache_free(posix_timers_cache, tmr); 548 return NULL; 549 } 550 memset(&tmr->sigq->info, 0, sizeof(siginfo_t)); 551 return tmr; 552 } 553 554 static void k_itimer_rcu_free(struct rcu_head *head) 555 { 556 struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu); 557 558 kmem_cache_free(posix_timers_cache, tmr); 559 } 560 561 #define IT_ID_SET 1 562 #define IT_ID_NOT_SET 0 563 static void release_posix_timer(struct k_itimer *tmr, int it_id_set) 564 { 565 if (it_id_set) { 566 unsigned long flags; 567 spin_lock_irqsave(&hash_lock, flags); 568 hlist_del_rcu(&tmr->t_hash); 569 spin_unlock_irqrestore(&hash_lock, flags); 570 } 571 put_pid(tmr->it_pid); 572 sigqueue_free(tmr->sigq); 573 call_rcu(&tmr->it.rcu, k_itimer_rcu_free); 574 } 575 576 static struct k_clock *clockid_to_kclock(const clockid_t id) 577 { 578 if (id < 0) 579 return (id & CLOCKFD_MASK) == CLOCKFD ? 580 &clock_posix_dynamic : &clock_posix_cpu; 581 582 if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres) 583 return NULL; 584 return &posix_clocks[id]; 585 } 586 587 static int common_timer_create(struct k_itimer *new_timer) 588 { 589 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0); 590 return 0; 591 } 592 593 /* Create a POSIX.1b interval timer. */ 594 595 SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock, 596 struct sigevent __user *, timer_event_spec, 597 timer_t __user *, created_timer_id) 598 { 599 struct k_clock *kc = clockid_to_kclock(which_clock); 600 struct k_itimer *new_timer; 601 int error, new_timer_id; 602 sigevent_t event; 603 int it_id_set = IT_ID_NOT_SET; 604 605 if (!kc) 606 return -EINVAL; 607 if (!kc->timer_create) 608 return -EOPNOTSUPP; 609 610 new_timer = alloc_posix_timer(); 611 if (unlikely(!new_timer)) 612 return -EAGAIN; 613 614 spin_lock_init(&new_timer->it_lock); 615 new_timer_id = posix_timer_add(new_timer); 616 if (new_timer_id < 0) { 617 error = new_timer_id; 618 goto out; 619 } 620 621 it_id_set = IT_ID_SET; 622 new_timer->it_id = (timer_t) new_timer_id; 623 new_timer->it_clock = which_clock; 624 new_timer->it_overrun = -1; 625 626 if (timer_event_spec) { 627 if (copy_from_user(&event, timer_event_spec, sizeof (event))) { 628 error = -EFAULT; 629 goto out; 630 } 631 rcu_read_lock(); 632 new_timer->it_pid = get_pid(good_sigevent(&event)); 633 rcu_read_unlock(); 634 if (!new_timer->it_pid) { 635 error = -EINVAL; 636 goto out; 637 } 638 } else { 639 event.sigev_notify = SIGEV_SIGNAL; 640 event.sigev_signo = SIGALRM; 641 event.sigev_value.sival_int = new_timer->it_id; 642 new_timer->it_pid = get_pid(task_tgid(current)); 643 } 644 645 new_timer->it_sigev_notify = event.sigev_notify; 646 new_timer->sigq->info.si_signo = event.sigev_signo; 647 new_timer->sigq->info.si_value = event.sigev_value; 648 new_timer->sigq->info.si_tid = new_timer->it_id; 649 new_timer->sigq->info.si_code = SI_TIMER; 650 651 if (copy_to_user(created_timer_id, 652 &new_timer_id, sizeof (new_timer_id))) { 653 error = -EFAULT; 654 goto out; 655 } 656 657 error = kc->timer_create(new_timer); 658 if (error) 659 goto out; 660 661 spin_lock_irq(¤t->sighand->siglock); 662 new_timer->it_signal = current->signal; 663 list_add(&new_timer->list, ¤t->signal->posix_timers); 664 spin_unlock_irq(¤t->sighand->siglock); 665 666 return 0; 667 /* 668 * In the case of the timer belonging to another task, after 669 * the task is unlocked, the timer is owned by the other task 670 * and may cease to exist at any time. Don't use or modify 671 * new_timer after the unlock call. 672 */ 673 out: 674 release_posix_timer(new_timer, it_id_set); 675 return error; 676 } 677 678 /* 679 * Locking issues: We need to protect the result of the id look up until 680 * we get the timer locked down so it is not deleted under us. The 681 * removal is done under the idr spinlock so we use that here to bridge 682 * the find to the timer lock. To avoid a dead lock, the timer id MUST 683 * be release with out holding the timer lock. 684 */ 685 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags) 686 { 687 struct k_itimer *timr; 688 689 /* 690 * timer_t could be any type >= int and we want to make sure any 691 * @timer_id outside positive int range fails lookup. 692 */ 693 if ((unsigned long long)timer_id > INT_MAX) 694 return NULL; 695 696 rcu_read_lock(); 697 timr = posix_timer_by_id(timer_id); 698 if (timr) { 699 spin_lock_irqsave(&timr->it_lock, *flags); 700 if (timr->it_signal == current->signal) { 701 rcu_read_unlock(); 702 return timr; 703 } 704 spin_unlock_irqrestore(&timr->it_lock, *flags); 705 } 706 rcu_read_unlock(); 707 708 return NULL; 709 } 710 711 /* 712 * Get the time remaining on a POSIX.1b interval timer. This function 713 * is ALWAYS called with spin_lock_irq on the timer, thus it must not 714 * mess with irq. 715 * 716 * We have a couple of messes to clean up here. First there is the case 717 * of a timer that has a requeue pending. These timers should appear to 718 * be in the timer list with an expiry as if we were to requeue them 719 * now. 720 * 721 * The second issue is the SIGEV_NONE timer which may be active but is 722 * not really ever put in the timer list (to save system resources). 723 * This timer may be expired, and if so, we will do it here. Otherwise 724 * it is the same as a requeue pending timer WRT to what we should 725 * report. 726 */ 727 static void 728 common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting) 729 { 730 ktime_t now, remaining, iv; 731 struct hrtimer *timer = &timr->it.real.timer; 732 733 memset(cur_setting, 0, sizeof(struct itimerspec)); 734 735 iv = timr->it.real.interval; 736 737 /* interval timer ? */ 738 if (iv.tv64) 739 cur_setting->it_interval = ktime_to_timespec(iv); 740 else if (!hrtimer_active(timer) && 741 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) 742 return; 743 744 now = timer->base->get_time(); 745 746 /* 747 * When a requeue is pending or this is a SIGEV_NONE 748 * timer move the expiry time forward by intervals, so 749 * expiry is > now. 750 */ 751 if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING || 752 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) 753 timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv); 754 755 remaining = ktime_sub(hrtimer_get_expires(timer), now); 756 /* Return 0 only, when the timer is expired and not pending */ 757 if (remaining.tv64 <= 0) { 758 /* 759 * A single shot SIGEV_NONE timer must return 0, when 760 * it is expired ! 761 */ 762 if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) 763 cur_setting->it_value.tv_nsec = 1; 764 } else 765 cur_setting->it_value = ktime_to_timespec(remaining); 766 } 767 768 /* Get the time remaining on a POSIX.1b interval timer. */ 769 SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id, 770 struct itimerspec __user *, setting) 771 { 772 struct itimerspec cur_setting; 773 struct k_itimer *timr; 774 struct k_clock *kc; 775 unsigned long flags; 776 int ret = 0; 777 778 timr = lock_timer(timer_id, &flags); 779 if (!timr) 780 return -EINVAL; 781 782 kc = clockid_to_kclock(timr->it_clock); 783 if (WARN_ON_ONCE(!kc || !kc->timer_get)) 784 ret = -EINVAL; 785 else 786 kc->timer_get(timr, &cur_setting); 787 788 unlock_timer(timr, flags); 789 790 if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting))) 791 return -EFAULT; 792 793 return ret; 794 } 795 796 /* 797 * Get the number of overruns of a POSIX.1b interval timer. This is to 798 * be the overrun of the timer last delivered. At the same time we are 799 * accumulating overruns on the next timer. The overrun is frozen when 800 * the signal is delivered, either at the notify time (if the info block 801 * is not queued) or at the actual delivery time (as we are informed by 802 * the call back to do_schedule_next_timer(). So all we need to do is 803 * to pick up the frozen overrun. 804 */ 805 SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id) 806 { 807 struct k_itimer *timr; 808 int overrun; 809 unsigned long flags; 810 811 timr = lock_timer(timer_id, &flags); 812 if (!timr) 813 return -EINVAL; 814 815 overrun = timr->it_overrun_last; 816 unlock_timer(timr, flags); 817 818 return overrun; 819 } 820 821 /* Set a POSIX.1b interval timer. */ 822 /* timr->it_lock is taken. */ 823 static int 824 common_timer_set(struct k_itimer *timr, int flags, 825 struct itimerspec *new_setting, struct itimerspec *old_setting) 826 { 827 struct hrtimer *timer = &timr->it.real.timer; 828 enum hrtimer_mode mode; 829 830 if (old_setting) 831 common_timer_get(timr, old_setting); 832 833 /* disable the timer */ 834 timr->it.real.interval.tv64 = 0; 835 /* 836 * careful here. If smp we could be in the "fire" routine which will 837 * be spinning as we hold the lock. But this is ONLY an SMP issue. 838 */ 839 if (hrtimer_try_to_cancel(timer) < 0) 840 return TIMER_RETRY; 841 842 timr->it_requeue_pending = (timr->it_requeue_pending + 2) & 843 ~REQUEUE_PENDING; 844 timr->it_overrun_last = 0; 845 846 /* switch off the timer when it_value is zero */ 847 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec) 848 return 0; 849 850 mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL; 851 hrtimer_init(&timr->it.real.timer, timr->it_clock, mode); 852 timr->it.real.timer.function = posix_timer_fn; 853 854 hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value)); 855 856 /* Convert interval */ 857 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval); 858 859 /* SIGEV_NONE timers are not queued ! See common_timer_get */ 860 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) { 861 /* Setup correct expiry time for relative timers */ 862 if (mode == HRTIMER_MODE_REL) { 863 hrtimer_add_expires(timer, timer->base->get_time()); 864 } 865 return 0; 866 } 867 868 hrtimer_start_expires(timer, mode); 869 return 0; 870 } 871 872 /* Set a POSIX.1b interval timer */ 873 SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags, 874 const struct itimerspec __user *, new_setting, 875 struct itimerspec __user *, old_setting) 876 { 877 struct k_itimer *timr; 878 struct itimerspec new_spec, old_spec; 879 int error = 0; 880 unsigned long flag; 881 struct itimerspec *rtn = old_setting ? &old_spec : NULL; 882 struct k_clock *kc; 883 884 if (!new_setting) 885 return -EINVAL; 886 887 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec))) 888 return -EFAULT; 889 890 if (!timespec_valid(&new_spec.it_interval) || 891 !timespec_valid(&new_spec.it_value)) 892 return -EINVAL; 893 retry: 894 timr = lock_timer(timer_id, &flag); 895 if (!timr) 896 return -EINVAL; 897 898 kc = clockid_to_kclock(timr->it_clock); 899 if (WARN_ON_ONCE(!kc || !kc->timer_set)) 900 error = -EINVAL; 901 else 902 error = kc->timer_set(timr, flags, &new_spec, rtn); 903 904 unlock_timer(timr, flag); 905 if (error == TIMER_RETRY) { 906 rtn = NULL; // We already got the old time... 907 goto retry; 908 } 909 910 if (old_setting && !error && 911 copy_to_user(old_setting, &old_spec, sizeof (old_spec))) 912 error = -EFAULT; 913 914 return error; 915 } 916 917 static int common_timer_del(struct k_itimer *timer) 918 { 919 timer->it.real.interval.tv64 = 0; 920 921 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0) 922 return TIMER_RETRY; 923 return 0; 924 } 925 926 static inline int timer_delete_hook(struct k_itimer *timer) 927 { 928 struct k_clock *kc = clockid_to_kclock(timer->it_clock); 929 930 if (WARN_ON_ONCE(!kc || !kc->timer_del)) 931 return -EINVAL; 932 return kc->timer_del(timer); 933 } 934 935 /* Delete a POSIX.1b interval timer. */ 936 SYSCALL_DEFINE1(timer_delete, timer_t, timer_id) 937 { 938 struct k_itimer *timer; 939 unsigned long flags; 940 941 retry_delete: 942 timer = lock_timer(timer_id, &flags); 943 if (!timer) 944 return -EINVAL; 945 946 if (timer_delete_hook(timer) == TIMER_RETRY) { 947 unlock_timer(timer, flags); 948 goto retry_delete; 949 } 950 951 spin_lock(¤t->sighand->siglock); 952 list_del(&timer->list); 953 spin_unlock(¤t->sighand->siglock); 954 /* 955 * This keeps any tasks waiting on the spin lock from thinking 956 * they got something (see the lock code above). 957 */ 958 timer->it_signal = NULL; 959 960 unlock_timer(timer, flags); 961 release_posix_timer(timer, IT_ID_SET); 962 return 0; 963 } 964 965 /* 966 * return timer owned by the process, used by exit_itimers 967 */ 968 static void itimer_delete(struct k_itimer *timer) 969 { 970 unsigned long flags; 971 972 retry_delete: 973 spin_lock_irqsave(&timer->it_lock, flags); 974 975 if (timer_delete_hook(timer) == TIMER_RETRY) { 976 unlock_timer(timer, flags); 977 goto retry_delete; 978 } 979 list_del(&timer->list); 980 /* 981 * This keeps any tasks waiting on the spin lock from thinking 982 * they got something (see the lock code above). 983 */ 984 timer->it_signal = NULL; 985 986 unlock_timer(timer, flags); 987 release_posix_timer(timer, IT_ID_SET); 988 } 989 990 /* 991 * This is called by do_exit or de_thread, only when there are no more 992 * references to the shared signal_struct. 993 */ 994 void exit_itimers(struct signal_struct *sig) 995 { 996 struct k_itimer *tmr; 997 998 while (!list_empty(&sig->posix_timers)) { 999 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list); 1000 itimer_delete(tmr); 1001 } 1002 } 1003 1004 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock, 1005 const struct timespec __user *, tp) 1006 { 1007 struct k_clock *kc = clockid_to_kclock(which_clock); 1008 struct timespec new_tp; 1009 1010 if (!kc || !kc->clock_set) 1011 return -EINVAL; 1012 1013 if (copy_from_user(&new_tp, tp, sizeof (*tp))) 1014 return -EFAULT; 1015 1016 return kc->clock_set(which_clock, &new_tp); 1017 } 1018 1019 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock, 1020 struct timespec __user *,tp) 1021 { 1022 struct k_clock *kc = clockid_to_kclock(which_clock); 1023 struct timespec kernel_tp; 1024 int error; 1025 1026 if (!kc) 1027 return -EINVAL; 1028 1029 error = kc->clock_get(which_clock, &kernel_tp); 1030 1031 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp))) 1032 error = -EFAULT; 1033 1034 return error; 1035 } 1036 1037 SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock, 1038 struct timex __user *, utx) 1039 { 1040 struct k_clock *kc = clockid_to_kclock(which_clock); 1041 struct timex ktx; 1042 int err; 1043 1044 if (!kc) 1045 return -EINVAL; 1046 if (!kc->clock_adj) 1047 return -EOPNOTSUPP; 1048 1049 if (copy_from_user(&ktx, utx, sizeof(ktx))) 1050 return -EFAULT; 1051 1052 err = kc->clock_adj(which_clock, &ktx); 1053 1054 if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx))) 1055 return -EFAULT; 1056 1057 return err; 1058 } 1059 1060 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, 1061 struct timespec __user *, tp) 1062 { 1063 struct k_clock *kc = clockid_to_kclock(which_clock); 1064 struct timespec rtn_tp; 1065 int error; 1066 1067 if (!kc) 1068 return -EINVAL; 1069 1070 error = kc->clock_getres(which_clock, &rtn_tp); 1071 1072 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) 1073 error = -EFAULT; 1074 1075 return error; 1076 } 1077 1078 /* 1079 * nanosleep for monotonic and realtime clocks 1080 */ 1081 static int common_nsleep(const clockid_t which_clock, int flags, 1082 struct timespec *tsave, struct timespec __user *rmtp) 1083 { 1084 return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ? 1085 HRTIMER_MODE_ABS : HRTIMER_MODE_REL, 1086 which_clock); 1087 } 1088 1089 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, 1090 const struct timespec __user *, rqtp, 1091 struct timespec __user *, rmtp) 1092 { 1093 struct k_clock *kc = clockid_to_kclock(which_clock); 1094 struct timespec t; 1095 1096 if (!kc) 1097 return -EINVAL; 1098 if (!kc->nsleep) 1099 return -ENANOSLEEP_NOTSUP; 1100 1101 if (copy_from_user(&t, rqtp, sizeof (struct timespec))) 1102 return -EFAULT; 1103 1104 if (!timespec_valid(&t)) 1105 return -EINVAL; 1106 1107 return kc->nsleep(which_clock, flags, &t, rmtp); 1108 } 1109 1110 /* 1111 * This will restart clock_nanosleep. This is required only by 1112 * compat_clock_nanosleep_restart for now. 1113 */ 1114 long clock_nanosleep_restart(struct restart_block *restart_block) 1115 { 1116 clockid_t which_clock = restart_block->nanosleep.clockid; 1117 struct k_clock *kc = clockid_to_kclock(which_clock); 1118 1119 if (WARN_ON_ONCE(!kc || !kc->nsleep_restart)) 1120 return -EINVAL; 1121 1122 return kc->nsleep_restart(restart_block); 1123 } 1124