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 */ 66static struct kmem_cache *posix_timers_cache; 67 68static DEFINE_HASHTABLE(posix_timers_hashtable, 9); 69static 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 127static struct k_clock posix_clocks[MAX_CLOCKS]; 128 129/* 130 * These ones are defined below. 131 */ 132static int common_nsleep(const clockid_t, int flags, struct timespec *t, 133 struct timespec __user *rmtp); 134static int common_timer_create(struct k_itimer *new_timer); 135static void common_timer_get(struct k_itimer *, struct itimerspec *); 136static int common_timer_set(struct k_itimer *, int, 137 struct itimerspec *, struct itimerspec *); 138static int common_timer_del(struct k_itimer *timer); 139 140static enum hrtimer_restart posix_timer_fn(struct hrtimer *data); 141 142static 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 150static 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 155static 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 168static 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 176static 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 200static 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 */ 206static 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 */ 213static 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 219static 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 */ 228static 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 */ 237static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp) 238{ 239 getrawmonotonic(tp); 240 return 0; 241} 242 243 244static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp) 245{ 246 *tp = current_kernel_time(); 247 return 0; 248} 249 250static int posix_get_monotonic_coarse(clockid_t which_clock, 251 struct timespec *tp) 252{ 253 *tp = get_monotonic_coarse(); 254 return 0; 255} 256 257static 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 263static int posix_get_boottime(const clockid_t which_clock, struct timespec *tp) 264{ 265 get_monotonic_boottime(tp); 266 return 0; 267} 268 269static 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 */ 278static __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 351static 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 */ 379void 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 399int 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} 426EXPORT_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 */ 435static 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 499static 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 516void 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} 538EXPORT_SYMBOL_GPL(posix_timers_register_clock); 539 540static 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 554static 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 563static 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 576static 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 587static 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 595SYSCALL_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 memset(&event.sigev_value, 0, sizeof(event.sigev_value)); 640 event.sigev_notify = SIGEV_SIGNAL; 641 event.sigev_signo = SIGALRM; 642 event.sigev_value.sival_int = new_timer->it_id; 643 new_timer->it_pid = get_pid(task_tgid(current)); 644 } 645 646 new_timer->it_sigev_notify = event.sigev_notify; 647 new_timer->sigq->info.si_signo = event.sigev_signo; 648 new_timer->sigq->info.si_value = event.sigev_value; 649 new_timer->sigq->info.si_tid = new_timer->it_id; 650 new_timer->sigq->info.si_code = SI_TIMER; 651 652 if (copy_to_user(created_timer_id, 653 &new_timer_id, sizeof (new_timer_id))) { 654 error = -EFAULT; 655 goto out; 656 } 657 658 error = kc->timer_create(new_timer); 659 if (error) 660 goto out; 661 662 spin_lock_irq(¤t->sighand->siglock); 663 new_timer->it_signal = current->signal; 664 list_add(&new_timer->list, ¤t->signal->posix_timers); 665 spin_unlock_irq(¤t->sighand->siglock); 666 667 return 0; 668 /* 669 * In the case of the timer belonging to another task, after 670 * the task is unlocked, the timer is owned by the other task 671 * and may cease to exist at any time. Don't use or modify 672 * new_timer after the unlock call. 673 */ 674out: 675 release_posix_timer(new_timer, it_id_set); 676 return error; 677} 678 679/* 680 * Locking issues: We need to protect the result of the id look up until 681 * we get the timer locked down so it is not deleted under us. The 682 * removal is done under the idr spinlock so we use that here to bridge 683 * the find to the timer lock. To avoid a dead lock, the timer id MUST 684 * be release with out holding the timer lock. 685 */ 686static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags) 687{ 688 struct k_itimer *timr; 689 690 /* 691 * timer_t could be any type >= int and we want to make sure any 692 * @timer_id outside positive int range fails lookup. 693 */ 694 if ((unsigned long long)timer_id > INT_MAX) 695 return NULL; 696 697 rcu_read_lock(); 698 timr = posix_timer_by_id(timer_id); 699 if (timr) { 700 spin_lock_irqsave(&timr->it_lock, *flags); 701 if (timr->it_signal == current->signal) { 702 rcu_read_unlock(); 703 return timr; 704 } 705 spin_unlock_irqrestore(&timr->it_lock, *flags); 706 } 707 rcu_read_unlock(); 708 709 return NULL; 710} 711 712/* 713 * Get the time remaining on a POSIX.1b interval timer. This function 714 * is ALWAYS called with spin_lock_irq on the timer, thus it must not 715 * mess with irq. 716 * 717 * We have a couple of messes to clean up here. First there is the case 718 * of a timer that has a requeue pending. These timers should appear to 719 * be in the timer list with an expiry as if we were to requeue them 720 * now. 721 * 722 * The second issue is the SIGEV_NONE timer which may be active but is 723 * not really ever put in the timer list (to save system resources). 724 * This timer may be expired, and if so, we will do it here. Otherwise 725 * it is the same as a requeue pending timer WRT to what we should 726 * report. 727 */ 728static void 729common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting) 730{ 731 ktime_t now, remaining, iv; 732 struct hrtimer *timer = &timr->it.real.timer; 733 734 memset(cur_setting, 0, sizeof(struct itimerspec)); 735 736 iv = timr->it.real.interval; 737 738 /* interval timer ? */ 739 if (iv.tv64) 740 cur_setting->it_interval = ktime_to_timespec(iv); 741 else if (!hrtimer_active(timer) && 742 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) 743 return; 744 745 now = timer->base->get_time(); 746 747 /* 748 * When a requeue is pending or this is a SIGEV_NONE 749 * timer move the expiry time forward by intervals, so 750 * expiry is > now. 751 */ 752 if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING || 753 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) 754 timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv); 755 756 remaining = ktime_sub(hrtimer_get_expires(timer), now); 757 /* Return 0 only, when the timer is expired and not pending */ 758 if (remaining.tv64 <= 0) { 759 /* 760 * A single shot SIGEV_NONE timer must return 0, when 761 * it is expired ! 762 */ 763 if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) 764 cur_setting->it_value.tv_nsec = 1; 765 } else 766 cur_setting->it_value = ktime_to_timespec(remaining); 767} 768 769/* Get the time remaining on a POSIX.1b interval timer. */ 770SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id, 771 struct itimerspec __user *, setting) 772{ 773 struct itimerspec cur_setting; 774 struct k_itimer *timr; 775 struct k_clock *kc; 776 unsigned long flags; 777 int ret = 0; 778 779 timr = lock_timer(timer_id, &flags); 780 if (!timr) 781 return -EINVAL; 782 783 kc = clockid_to_kclock(timr->it_clock); 784 if (WARN_ON_ONCE(!kc || !kc->timer_get)) 785 ret = -EINVAL; 786 else 787 kc->timer_get(timr, &cur_setting); 788 789 unlock_timer(timr, flags); 790 791 if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting))) 792 return -EFAULT; 793 794 return ret; 795} 796 797/* 798 * Get the number of overruns of a POSIX.1b interval timer. This is to 799 * be the overrun of the timer last delivered. At the same time we are 800 * accumulating overruns on the next timer. The overrun is frozen when 801 * the signal is delivered, either at the notify time (if the info block 802 * is not queued) or at the actual delivery time (as we are informed by 803 * the call back to do_schedule_next_timer(). So all we need to do is 804 * to pick up the frozen overrun. 805 */ 806SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id) 807{ 808 struct k_itimer *timr; 809 int overrun; 810 unsigned long flags; 811 812 timr = lock_timer(timer_id, &flags); 813 if (!timr) 814 return -EINVAL; 815 816 overrun = timr->it_overrun_last; 817 unlock_timer(timr, flags); 818 819 return overrun; 820} 821 822/* Set a POSIX.1b interval timer. */ 823/* timr->it_lock is taken. */ 824static int 825common_timer_set(struct k_itimer *timr, int flags, 826 struct itimerspec *new_setting, struct itimerspec *old_setting) 827{ 828 struct hrtimer *timer = &timr->it.real.timer; 829 enum hrtimer_mode mode; 830 831 if (old_setting) 832 common_timer_get(timr, old_setting); 833 834 /* disable the timer */ 835 timr->it.real.interval.tv64 = 0; 836 /* 837 * careful here. If smp we could be in the "fire" routine which will 838 * be spinning as we hold the lock. But this is ONLY an SMP issue. 839 */ 840 if (hrtimer_try_to_cancel(timer) < 0) 841 return TIMER_RETRY; 842 843 timr->it_requeue_pending = (timr->it_requeue_pending + 2) & 844 ~REQUEUE_PENDING; 845 timr->it_overrun_last = 0; 846 847 /* switch off the timer when it_value is zero */ 848 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec) 849 return 0; 850 851 mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL; 852 hrtimer_init(&timr->it.real.timer, timr->it_clock, mode); 853 timr->it.real.timer.function = posix_timer_fn; 854 855 hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value)); 856 857 /* Convert interval */ 858 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval); 859 860 /* SIGEV_NONE timers are not queued ! See common_timer_get */ 861 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) { 862 /* Setup correct expiry time for relative timers */ 863 if (mode == HRTIMER_MODE_REL) { 864 hrtimer_add_expires(timer, timer->base->get_time()); 865 } 866 return 0; 867 } 868 869 hrtimer_start_expires(timer, mode); 870 return 0; 871} 872 873/* Set a POSIX.1b interval timer */ 874SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags, 875 const struct itimerspec __user *, new_setting, 876 struct itimerspec __user *, old_setting) 877{ 878 struct k_itimer *timr; 879 struct itimerspec new_spec, old_spec; 880 int error = 0; 881 unsigned long flag; 882 struct itimerspec *rtn = old_setting ? &old_spec : NULL; 883 struct k_clock *kc; 884 885 if (!new_setting) 886 return -EINVAL; 887 888 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec))) 889 return -EFAULT; 890 891 if (!timespec_valid(&new_spec.it_interval) || 892 !timespec_valid(&new_spec.it_value)) 893 return -EINVAL; 894retry: 895 timr = lock_timer(timer_id, &flag); 896 if (!timr) 897 return -EINVAL; 898 899 kc = clockid_to_kclock(timr->it_clock); 900 if (WARN_ON_ONCE(!kc || !kc->timer_set)) 901 error = -EINVAL; 902 else 903 error = kc->timer_set(timr, flags, &new_spec, rtn); 904 905 unlock_timer(timr, flag); 906 if (error == TIMER_RETRY) { 907 rtn = NULL; // We already got the old time... 908 goto retry; 909 } 910 911 if (old_setting && !error && 912 copy_to_user(old_setting, &old_spec, sizeof (old_spec))) 913 error = -EFAULT; 914 915 return error; 916} 917 918static int common_timer_del(struct k_itimer *timer) 919{ 920 timer->it.real.interval.tv64 = 0; 921 922 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0) 923 return TIMER_RETRY; 924 return 0; 925} 926 927static inline int timer_delete_hook(struct k_itimer *timer) 928{ 929 struct k_clock *kc = clockid_to_kclock(timer->it_clock); 930 931 if (WARN_ON_ONCE(!kc || !kc->timer_del)) 932 return -EINVAL; 933 return kc->timer_del(timer); 934} 935 936/* Delete a POSIX.1b interval timer. */ 937SYSCALL_DEFINE1(timer_delete, timer_t, timer_id) 938{ 939 struct k_itimer *timer; 940 unsigned long flags; 941 942retry_delete: 943 timer = lock_timer(timer_id, &flags); 944 if (!timer) 945 return -EINVAL; 946 947 if (timer_delete_hook(timer) == TIMER_RETRY) { 948 unlock_timer(timer, flags); 949 goto retry_delete; 950 } 951 952 spin_lock(¤t->sighand->siglock); 953 list_del(&timer->list); 954 spin_unlock(¤t->sighand->siglock); 955 /* 956 * This keeps any tasks waiting on the spin lock from thinking 957 * they got something (see the lock code above). 958 */ 959 timer->it_signal = NULL; 960 961 unlock_timer(timer, flags); 962 release_posix_timer(timer, IT_ID_SET); 963 return 0; 964} 965 966/* 967 * return timer owned by the process, used by exit_itimers 968 */ 969static void itimer_delete(struct k_itimer *timer) 970{ 971 unsigned long flags; 972 973retry_delete: 974 spin_lock_irqsave(&timer->it_lock, flags); 975 976 if (timer_delete_hook(timer) == TIMER_RETRY) { 977 unlock_timer(timer, flags); 978 goto retry_delete; 979 } 980 list_del(&timer->list); 981 /* 982 * This keeps any tasks waiting on the spin lock from thinking 983 * they got something (see the lock code above). 984 */ 985 timer->it_signal = NULL; 986 987 unlock_timer(timer, flags); 988 release_posix_timer(timer, IT_ID_SET); 989} 990 991/* 992 * This is called by do_exit or de_thread, only when there are no more 993 * references to the shared signal_struct. 994 */ 995void exit_itimers(struct signal_struct *sig) 996{ 997 struct k_itimer *tmr; 998 999 while (!list_empty(&sig->posix_timers)) { 1000 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list); 1001 itimer_delete(tmr); 1002 } 1003} 1004 1005SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock, 1006 const struct timespec __user *, tp) 1007{ 1008 struct k_clock *kc = clockid_to_kclock(which_clock); 1009 struct timespec new_tp; 1010 1011 if (!kc || !kc->clock_set) 1012 return -EINVAL; 1013 1014 if (copy_from_user(&new_tp, tp, sizeof (*tp))) 1015 return -EFAULT; 1016 1017 return kc->clock_set(which_clock, &new_tp); 1018} 1019 1020SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock, 1021 struct timespec __user *,tp) 1022{ 1023 struct k_clock *kc = clockid_to_kclock(which_clock); 1024 struct timespec kernel_tp; 1025 int error; 1026 1027 if (!kc) 1028 return -EINVAL; 1029 1030 error = kc->clock_get(which_clock, &kernel_tp); 1031 1032 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp))) 1033 error = -EFAULT; 1034 1035 return error; 1036} 1037 1038SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock, 1039 struct timex __user *, utx) 1040{ 1041 struct k_clock *kc = clockid_to_kclock(which_clock); 1042 struct timex ktx; 1043 int err; 1044 1045 if (!kc) 1046 return -EINVAL; 1047 if (!kc->clock_adj) 1048 return -EOPNOTSUPP; 1049 1050 if (copy_from_user(&ktx, utx, sizeof(ktx))) 1051 return -EFAULT; 1052 1053 err = kc->clock_adj(which_clock, &ktx); 1054 1055 if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx))) 1056 return -EFAULT; 1057 1058 return err; 1059} 1060 1061SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, 1062 struct timespec __user *, tp) 1063{ 1064 struct k_clock *kc = clockid_to_kclock(which_clock); 1065 struct timespec rtn_tp; 1066 int error; 1067 1068 if (!kc) 1069 return -EINVAL; 1070 1071 error = kc->clock_getres(which_clock, &rtn_tp); 1072 1073 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) 1074 error = -EFAULT; 1075 1076 return error; 1077} 1078 1079/* 1080 * nanosleep for monotonic and realtime clocks 1081 */ 1082static int common_nsleep(const clockid_t which_clock, int flags, 1083 struct timespec *tsave, struct timespec __user *rmtp) 1084{ 1085 return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ? 1086 HRTIMER_MODE_ABS : HRTIMER_MODE_REL, 1087 which_clock); 1088} 1089 1090SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, 1091 const struct timespec __user *, rqtp, 1092 struct timespec __user *, rmtp) 1093{ 1094 struct k_clock *kc = clockid_to_kclock(which_clock); 1095 struct timespec t; 1096 1097 if (!kc) 1098 return -EINVAL; 1099 if (!kc->nsleep) 1100 return -ENANOSLEEP_NOTSUP; 1101 1102 if (copy_from_user(&t, rqtp, sizeof (struct timespec))) 1103 return -EFAULT; 1104 1105 if (!timespec_valid(&t)) 1106 return -EINVAL; 1107 1108 return kc->nsleep(which_clock, flags, &t, rmtp); 1109} 1110 1111/* 1112 * This will restart clock_nanosleep. This is required only by 1113 * compat_clock_nanosleep_restart for now. 1114 */ 1115long clock_nanosleep_restart(struct restart_block *restart_block) 1116{ 1117 clockid_t which_clock = restart_block->nanosleep.clockid; 1118 struct k_clock *kc = clockid_to_kclock(which_clock); 1119 1120 if (WARN_ON_ONCE(!kc || !kc->nsleep_restart)) 1121 return -EINVAL; 1122 1123 return kc->nsleep_restart(restart_block); 1124} 1125