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/idr.h> 44#include <linux/posix-timers.h> 45#include <linux/syscalls.h> 46#include <linux/wait.h> 47#include <linux/workqueue.h> 48#include <linux/module.h> 49 50/* 51 * Management arrays for POSIX timers. Timers are kept in slab memory 52 * Timer ids are allocated by an external routine that keeps track of the 53 * id and the timer. The external interface is: 54 * 55 * void *idr_find(struct idr *idp, int id); to find timer_id <id> 56 * int idr_get_new(struct idr *idp, void *ptr); to get a new id and 57 * related it to <ptr> 58 * void idr_remove(struct idr *idp, int id); to release <id> 59 * void idr_init(struct idr *idp); to initialize <idp> 60 * which we supply. 61 * The idr_get_new *may* call slab for more memory so it must not be 62 * called under a spin lock. Likewise idr_remore may release memory 63 * (but it may be ok to do this under a lock...). 64 * idr_find is just a memory look up and is quite fast. A -1 return 65 * indicates that the requested id does not exist. 66 */ 67 68/* 69 * Lets keep our timers in a slab cache :-) 70 */ 71static struct kmem_cache *posix_timers_cache; 72static struct idr posix_timers_id; 73static DEFINE_SPINLOCK(idr_lock); 74 75/* 76 * we assume that the new SIGEV_THREAD_ID shares no bits with the other 77 * SIGEV values. Here we put out an error if this assumption fails. 78 */ 79#if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD)) 80#error "SIGEV_THREAD_ID must not share bit with other SIGEV values!" 81#endif 82 83 84/* 85 * The timer ID is turned into a timer address by idr_find(). 86 * Verifying a valid ID consists of: 87 * 88 * a) checking that idr_find() returns other than -1. 89 * b) checking that the timer id matches the one in the timer itself. 90 * c) that the timer owner is in the callers thread group. 91 */ 92 93/* 94 * CLOCKs: The POSIX standard calls for a couple of clocks and allows us 95 * to implement others. This structure defines the various 96 * clocks and allows the possibility of adding others. We 97 * provide an interface to add clocks to the table and expect 98 * the "arch" code to add at least one clock that is high 99 * resolution. Here we define the standard CLOCK_REALTIME as a 100 * 1/HZ resolution clock. 101 * 102 * RESOLUTION: Clock resolution is used to round up timer and interval 103 * times, NOT to report clock times, which are reported with as 104 * much resolution as the system can muster. In some cases this 105 * resolution may depend on the underlying clock hardware and 106 * may not be quantifiable until run time, and only then is the 107 * necessary code is written. The standard says we should say 108 * something about this issue in the documentation... 109 * 110 * FUNCTIONS: The CLOCKs structure defines possible functions to handle 111 * various clock functions. For clocks that use the standard 112 * system timer code these entries should be NULL. This will 113 * allow dispatch without the overhead of indirect function 114 * calls. CLOCKS that depend on other sources (e.g. WWV or GPS) 115 * must supply functions here, even if the function just returns 116 * ENOSYS. The standard POSIX timer management code assumes the 117 * following: 1.) The k_itimer struct (sched.h) is used for the 118 * timer. 2.) The list, it_lock, it_clock, it_id and it_pid 119 * fields are not modified by timer code. 120 * 121 * At this time all functions EXCEPT clock_nanosleep can be 122 * redirected by the CLOCKS structure. Clock_nanosleep is in 123 * there, but the code ignores it. 124 * 125 * Permissions: It is assumed that the clock_settime() function defined 126 * for each clock will take care of permission checks. Some 127 * clocks may be set able by any user (i.e. local process 128 * clocks) others not. Currently the only set able clock we 129 * have is CLOCK_REALTIME and its high res counter part, both of 130 * which we beg off on and pass to do_sys_settimeofday(). 131 */ 132 133static struct k_clock posix_clocks[MAX_CLOCKS]; 134 135/* 136 * These ones are defined below. 137 */ 138static int common_nsleep(const clockid_t, int flags, struct timespec *t, 139 struct timespec __user *rmtp); 140static void common_timer_get(struct k_itimer *, struct itimerspec *); 141static int common_timer_set(struct k_itimer *, int, 142 struct itimerspec *, struct itimerspec *); 143static int common_timer_del(struct k_itimer *timer); 144 145static enum hrtimer_restart posix_timer_fn(struct hrtimer *data); 146 147static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags); 148 149static inline void unlock_timer(struct k_itimer *timr, unsigned long flags) 150{ 151 spin_unlock_irqrestore(&timr->it_lock, flags); 152} 153 154/* 155 * Call the k_clock hook function if non-null, or the default function. 156 */ 157#define CLOCK_DISPATCH(clock, call, arglist) \ 158 ((clock) < 0 ? posix_cpu_##call arglist : \ 159 (posix_clocks[clock].call != NULL \ 160 ? (*posix_clocks[clock].call) arglist : common_##call arglist)) 161 162/* 163 * Default clock hook functions when the struct k_clock passed 164 * to register_posix_clock leaves a function pointer null. 165 * 166 * The function common_CALL is the default implementation for 167 * the function pointer CALL in struct k_clock. 168 */ 169 170static inline int common_clock_getres(const clockid_t which_clock, 171 struct timespec *tp) 172{ 173 tp->tv_sec = 0; 174 tp->tv_nsec = posix_clocks[which_clock].res; 175 return 0; 176} 177 178/* 179 * Get real time for posix timers 180 */ 181static int common_clock_get(clockid_t which_clock, struct timespec *tp) 182{ 183 ktime_get_real_ts(tp); 184 return 0; 185} 186 187static inline int common_clock_set(const clockid_t which_clock, 188 struct timespec *tp) 189{ 190 return do_sys_settimeofday(tp, NULL); 191} 192 193static int common_timer_create(struct k_itimer *new_timer) 194{ 195 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0); 196 return 0; 197} 198 199static int no_timer_create(struct k_itimer *new_timer) 200{ 201 return -EOPNOTSUPP; 202} 203 204static int no_nsleep(const clockid_t which_clock, int flags, 205 struct timespec *tsave, struct timespec __user *rmtp) 206{ 207 return -EOPNOTSUPP; 208} 209 210/* 211 * Return nonzero if we know a priori this clockid_t value is bogus. 212 */ 213static inline int invalid_clockid(const clockid_t which_clock) 214{ 215 if (which_clock < 0) /* CPU clock, posix_cpu_* will check it */ 216 return 0; 217 if ((unsigned) which_clock >= MAX_CLOCKS) 218 return 1; 219 if (posix_clocks[which_clock].clock_getres != NULL) 220 return 0; 221 if (posix_clocks[which_clock].res != 0) 222 return 0; 223 return 1; 224} 225 226/* 227 * Get monotonic time for posix timers 228 */ 229static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp) 230{ 231 ktime_get_ts(tp); 232 return 0; 233} 234 235/* 236 * Get monotonic time for posix timers 237 */ 238static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp) 239{ 240 getrawmonotonic(tp); 241 return 0; 242} 243 244 245static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp) 246{ 247 *tp = current_kernel_time(); 248 return 0; 249} 250 251static int posix_get_monotonic_coarse(clockid_t which_clock, 252 struct timespec *tp) 253{ 254 *tp = get_monotonic_coarse(); 255 return 0; 256} 257 258static int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp) 259{ 260 *tp = ktime_to_timespec(KTIME_LOW_RES); 261 return 0; 262} 263/* 264 * Initialize everything, well, just everything in Posix clocks/timers ;) 265 */ 266static __init int init_posix_timers(void) 267{ 268 struct k_clock clock_realtime = { 269 .clock_getres = hrtimer_get_res, 270 }; 271 struct k_clock clock_monotonic = { 272 .clock_getres = hrtimer_get_res, 273 .clock_get = posix_ktime_get_ts, 274 .clock_set = do_posix_clock_nosettime, 275 }; 276 struct k_clock clock_monotonic_raw = { 277 .clock_getres = hrtimer_get_res, 278 .clock_get = posix_get_monotonic_raw, 279 .clock_set = do_posix_clock_nosettime, 280 .timer_create = no_timer_create, 281 .nsleep = no_nsleep, 282 }; 283 struct k_clock clock_realtime_coarse = { 284 .clock_getres = posix_get_coarse_res, 285 .clock_get = posix_get_realtime_coarse, 286 .clock_set = do_posix_clock_nosettime, 287 .timer_create = no_timer_create, 288 .nsleep = no_nsleep, 289 }; 290 struct k_clock clock_monotonic_coarse = { 291 .clock_getres = posix_get_coarse_res, 292 .clock_get = posix_get_monotonic_coarse, 293 .clock_set = do_posix_clock_nosettime, 294 .timer_create = no_timer_create, 295 .nsleep = no_nsleep, 296 }; 297 298 register_posix_clock(CLOCK_REALTIME, &clock_realtime); 299 register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic); 300 register_posix_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw); 301 register_posix_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse); 302 register_posix_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse); 303 304 posix_timers_cache = kmem_cache_create("posix_timers_cache", 305 sizeof (struct k_itimer), 0, SLAB_PANIC, 306 NULL); 307 idr_init(&posix_timers_id); 308 return 0; 309} 310 311__initcall(init_posix_timers); 312 313static void schedule_next_timer(struct k_itimer *timr) 314{ 315 struct hrtimer *timer = &timr->it.real.timer; 316 317 if (timr->it.real.interval.tv64 == 0) 318 return; 319 320 timr->it_overrun += (unsigned int) hrtimer_forward(timer, 321 timer->base->get_time(), 322 timr->it.real.interval); 323 324 timr->it_overrun_last = timr->it_overrun; 325 timr->it_overrun = -1; 326 ++timr->it_requeue_pending; 327 hrtimer_restart(timer); 328} 329 330/* 331 * This function is exported for use by the signal deliver code. It is 332 * called just prior to the info block being released and passes that 333 * block to us. It's function is to update the overrun entry AND to 334 * restart the timer. It should only be called if the timer is to be 335 * restarted (i.e. we have flagged this in the sys_private entry of the 336 * info block). 337 * 338 * To protect aginst the timer going away while the interrupt is queued, 339 * we require that the it_requeue_pending flag be set. 340 */ 341void do_schedule_next_timer(struct siginfo *info) 342{ 343 struct k_itimer *timr; 344 unsigned long flags; 345 346 timr = lock_timer(info->si_tid, &flags); 347 348 if (timr && timr->it_requeue_pending == info->si_sys_private) { 349 if (timr->it_clock < 0) 350 posix_cpu_timer_schedule(timr); 351 else 352 schedule_next_timer(timr); 353 354 info->si_overrun += timr->it_overrun_last; 355 } 356 357 if (timr) 358 unlock_timer(timr, flags); 359} 360 361int posix_timer_event(struct k_itimer *timr, int si_private) 362{ 363 struct task_struct *task; 364 int shared, ret = -1; 365 timr->sigq->info.si_sys_private = si_private; 366 367 rcu_read_lock(); 368 task = pid_task(timr->it_pid, PIDTYPE_PID); 369 if (task) { 370 shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID); 371 ret = send_sigqueue(timr->sigq, task, shared); 372 } 373 rcu_read_unlock(); 374 /* If we failed to send the signal the timer stops. */ 375 return ret > 0; 376} 377EXPORT_SYMBOL_GPL(posix_timer_event); 378 379/* 380 * This function gets called when a POSIX.1b interval timer expires. It 381 * is used as a callback from the kernel internal timer. The 382 * run_timer_list code ALWAYS calls with interrupts on. 383 384 * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers. 385 */ 386static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer) 387{ 388 struct k_itimer *timr; 389 unsigned long flags; 390 int si_private = 0; 391 enum hrtimer_restart ret = HRTIMER_NORESTART; 392 393 timr = container_of(timer, struct k_itimer, it.real.timer); 394 spin_lock_irqsave(&timr->it_lock, flags); 395 396 if (timr->it.real.interval.tv64 != 0) 397 si_private = ++timr->it_requeue_pending; 398 399 if (posix_timer_event(timr, si_private)) { 400 /* 401 * signal was not sent because of sig_ignor 402 * we will not get a call back to restart it AND 403 * it should be restarted. 404 */ 405 if (timr->it.real.interval.tv64 != 0) { 406 ktime_t now = hrtimer_cb_get_time(timer); 407 408#ifdef CONFIG_HIGH_RES_TIMERS 409 { 410 ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ); 411 412 if (timr->it.real.interval.tv64 < kj.tv64) 413 now = ktime_add(now, kj); 414 } 415#endif 416 timr->it_overrun += (unsigned int) 417 hrtimer_forward(timer, now, 418 timr->it.real.interval); 419 ret = HRTIMER_RESTART; 420 ++timr->it_requeue_pending; 421 } 422 } 423 424 unlock_timer(timr, flags); 425 return ret; 426} 427 428static struct pid *good_sigevent(sigevent_t * event) 429{ 430 struct task_struct *rtn = current->group_leader; 431 432 if ((event->sigev_notify & SIGEV_THREAD_ID ) && 433 (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) || 434 !same_thread_group(rtn, current) || 435 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL)) 436 return NULL; 437 438 if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) && 439 ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX))) 440 return NULL; 441 442 return task_pid(rtn); 443} 444 445void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock) 446{ 447 if ((unsigned) clock_id >= MAX_CLOCKS) { 448 printk("POSIX clock register failed for clock_id %d\n", 449 clock_id); 450 return; 451 } 452 453 posix_clocks[clock_id] = *new_clock; 454} 455EXPORT_SYMBOL_GPL(register_posix_clock); 456 457static struct k_itimer * alloc_posix_timer(void) 458{ 459 struct k_itimer *tmr; 460 tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL); 461 if (!tmr) 462 return tmr; 463 if (unlikely(!(tmr->sigq = sigqueue_alloc()))) { 464 kmem_cache_free(posix_timers_cache, tmr); 465 return NULL; 466 } 467 memset(&tmr->sigq->info, 0, sizeof(siginfo_t)); 468 return tmr; 469} 470 471#define IT_ID_SET 1 472#define IT_ID_NOT_SET 0 473static void release_posix_timer(struct k_itimer *tmr, int it_id_set) 474{ 475 if (it_id_set) { 476 unsigned long flags; 477 spin_lock_irqsave(&idr_lock, flags); 478 idr_remove(&posix_timers_id, tmr->it_id); 479 spin_unlock_irqrestore(&idr_lock, flags); 480 } 481 put_pid(tmr->it_pid); 482 sigqueue_free(tmr->sigq); 483 kmem_cache_free(posix_timers_cache, tmr); 484} 485 486/* Create a POSIX.1b interval timer. */ 487 488SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock, 489 struct sigevent __user *, timer_event_spec, 490 timer_t __user *, created_timer_id) 491{ 492 struct k_itimer *new_timer; 493 int error, new_timer_id; 494 sigevent_t event; 495 int it_id_set = IT_ID_NOT_SET; 496 497 if (invalid_clockid(which_clock)) 498 return -EINVAL; 499 500 new_timer = alloc_posix_timer(); 501 if (unlikely(!new_timer)) 502 return -EAGAIN; 503 504 spin_lock_init(&new_timer->it_lock); 505 retry: 506 if (unlikely(!idr_pre_get(&posix_timers_id, GFP_KERNEL))) { 507 error = -EAGAIN; 508 goto out; 509 } 510 spin_lock_irq(&idr_lock); 511 error = idr_get_new(&posix_timers_id, new_timer, &new_timer_id); 512 spin_unlock_irq(&idr_lock); 513 if (error) { 514 if (error == -EAGAIN) 515 goto retry; 516 /* 517 * Weird looking, but we return EAGAIN if the IDR is 518 * full (proper POSIX return value for this) 519 */ 520 error = -EAGAIN; 521 goto out; 522 } 523 524 it_id_set = IT_ID_SET; 525 new_timer->it_id = (timer_t) new_timer_id; 526 new_timer->it_clock = which_clock; 527 new_timer->it_overrun = -1; 528 529 if (timer_event_spec) { 530 if (copy_from_user(&event, timer_event_spec, sizeof (event))) { 531 error = -EFAULT; 532 goto out; 533 } 534 rcu_read_lock(); 535 new_timer->it_pid = get_pid(good_sigevent(&event)); 536 rcu_read_unlock(); 537 if (!new_timer->it_pid) { 538 error = -EINVAL; 539 goto out; 540 } 541 } else { 542 event.sigev_notify = SIGEV_SIGNAL; 543 event.sigev_signo = SIGALRM; 544 event.sigev_value.sival_int = new_timer->it_id; 545 new_timer->it_pid = get_pid(task_tgid(current)); 546 } 547 548 new_timer->it_sigev_notify = event.sigev_notify; 549 new_timer->sigq->info.si_signo = event.sigev_signo; 550 new_timer->sigq->info.si_value = event.sigev_value; 551 new_timer->sigq->info.si_tid = new_timer->it_id; 552 new_timer->sigq->info.si_code = SI_TIMER; 553 554 if (copy_to_user(created_timer_id, 555 &new_timer_id, sizeof (new_timer_id))) { 556 error = -EFAULT; 557 goto out; 558 } 559 560 error = CLOCK_DISPATCH(which_clock, timer_create, (new_timer)); 561 if (error) 562 goto out; 563 564 spin_lock_irq(¤t->sighand->siglock); 565 new_timer->it_signal = current->signal; 566 list_add(&new_timer->list, ¤t->signal->posix_timers); 567 spin_unlock_irq(¤t->sighand->siglock); 568 569 return 0; 570 /* 571 * In the case of the timer belonging to another task, after 572 * the task is unlocked, the timer is owned by the other task 573 * and may cease to exist at any time. Don't use or modify 574 * new_timer after the unlock call. 575 */ 576out: 577 release_posix_timer(new_timer, it_id_set); 578 return error; 579} 580 581/* 582 * Locking issues: We need to protect the result of the id look up until 583 * we get the timer locked down so it is not deleted under us. The 584 * removal is done under the idr spinlock so we use that here to bridge 585 * the find to the timer lock. To avoid a dead lock, the timer id MUST 586 * be release with out holding the timer lock. 587 */ 588static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags) 589{ 590 struct k_itimer *timr; 591 /* 592 * Watch out here. We do a irqsave on the idr_lock and pass the 593 * flags part over to the timer lock. Must not let interrupts in 594 * while we are moving the lock. 595 */ 596 spin_lock_irqsave(&idr_lock, *flags); 597 timr = idr_find(&posix_timers_id, (int)timer_id); 598 if (timr) { 599 spin_lock(&timr->it_lock); 600 if (timr->it_signal == current->signal) { 601 spin_unlock(&idr_lock); 602 return timr; 603 } 604 spin_unlock(&timr->it_lock); 605 } 606 spin_unlock_irqrestore(&idr_lock, *flags); 607 608 return NULL; 609} 610 611/* 612 * Get the time remaining on a POSIX.1b interval timer. This function 613 * is ALWAYS called with spin_lock_irq on the timer, thus it must not 614 * mess with irq. 615 * 616 * We have a couple of messes to clean up here. First there is the case 617 * of a timer that has a requeue pending. These timers should appear to 618 * be in the timer list with an expiry as if we were to requeue them 619 * now. 620 * 621 * The second issue is the SIGEV_NONE timer which may be active but is 622 * not really ever put in the timer list (to save system resources). 623 * This timer may be expired, and if so, we will do it here. Otherwise 624 * it is the same as a requeue pending timer WRT to what we should 625 * report. 626 */ 627static void 628common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting) 629{ 630 ktime_t now, remaining, iv; 631 struct hrtimer *timer = &timr->it.real.timer; 632 633 memset(cur_setting, 0, sizeof(struct itimerspec)); 634 635 iv = timr->it.real.interval; 636 637 /* interval timer ? */ 638 if (iv.tv64) 639 cur_setting->it_interval = ktime_to_timespec(iv); 640 else if (!hrtimer_active(timer) && 641 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) 642 return; 643 644 now = timer->base->get_time(); 645 646 /* 647 * When a requeue is pending or this is a SIGEV_NONE 648 * timer move the expiry time forward by intervals, so 649 * expiry is > now. 650 */ 651 if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING || 652 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) 653 timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv); 654 655 remaining = ktime_sub(hrtimer_get_expires(timer), now); 656 /* Return 0 only, when the timer is expired and not pending */ 657 if (remaining.tv64 <= 0) { 658 /* 659 * A single shot SIGEV_NONE timer must return 0, when 660 * it is expired ! 661 */ 662 if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) 663 cur_setting->it_value.tv_nsec = 1; 664 } else 665 cur_setting->it_value = ktime_to_timespec(remaining); 666} 667 668/* Get the time remaining on a POSIX.1b interval timer. */ 669SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id, 670 struct itimerspec __user *, setting) 671{ 672 struct k_itimer *timr; 673 struct itimerspec cur_setting; 674 unsigned long flags; 675 676 timr = lock_timer(timer_id, &flags); 677 if (!timr) 678 return -EINVAL; 679 680 CLOCK_DISPATCH(timr->it_clock, timer_get, (timr, &cur_setting)); 681 682 unlock_timer(timr, flags); 683 684 if (copy_to_user(setting, &cur_setting, sizeof (cur_setting))) 685 return -EFAULT; 686 687 return 0; 688} 689 690/* 691 * Get the number of overruns of a POSIX.1b interval timer. This is to 692 * be the overrun of the timer last delivered. At the same time we are 693 * accumulating overruns on the next timer. The overrun is frozen when 694 * the signal is delivered, either at the notify time (if the info block 695 * is not queued) or at the actual delivery time (as we are informed by 696 * the call back to do_schedule_next_timer(). So all we need to do is 697 * to pick up the frozen overrun. 698 */ 699SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id) 700{ 701 struct k_itimer *timr; 702 int overrun; 703 unsigned long flags; 704 705 timr = lock_timer(timer_id, &flags); 706 if (!timr) 707 return -EINVAL; 708 709 overrun = timr->it_overrun_last; 710 unlock_timer(timr, flags); 711 712 return overrun; 713} 714 715/* Set a POSIX.1b interval timer. */ 716/* timr->it_lock is taken. */ 717static int 718common_timer_set(struct k_itimer *timr, int flags, 719 struct itimerspec *new_setting, struct itimerspec *old_setting) 720{ 721 struct hrtimer *timer = &timr->it.real.timer; 722 enum hrtimer_mode mode; 723 724 if (old_setting) 725 common_timer_get(timr, old_setting); 726 727 /* disable the timer */ 728 timr->it.real.interval.tv64 = 0; 729 /* 730 * careful here. If smp we could be in the "fire" routine which will 731 * be spinning as we hold the lock. But this is ONLY an SMP issue. 732 */ 733 if (hrtimer_try_to_cancel(timer) < 0) 734 return TIMER_RETRY; 735 736 timr->it_requeue_pending = (timr->it_requeue_pending + 2) & 737 ~REQUEUE_PENDING; 738 timr->it_overrun_last = 0; 739 740 /* switch off the timer when it_value is zero */ 741 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec) 742 return 0; 743 744 mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL; 745 hrtimer_init(&timr->it.real.timer, timr->it_clock, mode); 746 timr->it.real.timer.function = posix_timer_fn; 747 748 hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value)); 749 750 /* Convert interval */ 751 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval); 752 753 /* SIGEV_NONE timers are not queued ! See common_timer_get */ 754 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) { 755 /* Setup correct expiry time for relative timers */ 756 if (mode == HRTIMER_MODE_REL) { 757 hrtimer_add_expires(timer, timer->base->get_time()); 758 } 759 return 0; 760 } 761 762 hrtimer_start_expires(timer, mode); 763 return 0; 764} 765 766/* Set a POSIX.1b interval timer */ 767SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags, 768 const struct itimerspec __user *, new_setting, 769 struct itimerspec __user *, old_setting) 770{ 771 struct k_itimer *timr; 772 struct itimerspec new_spec, old_spec; 773 int error = 0; 774 unsigned long flag; 775 struct itimerspec *rtn = old_setting ? &old_spec : NULL; 776 777 if (!new_setting) 778 return -EINVAL; 779 780 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec))) 781 return -EFAULT; 782 783 if (!timespec_valid(&new_spec.it_interval) || 784 !timespec_valid(&new_spec.it_value)) 785 return -EINVAL; 786retry: 787 timr = lock_timer(timer_id, &flag); 788 if (!timr) 789 return -EINVAL; 790 791 error = CLOCK_DISPATCH(timr->it_clock, timer_set, 792 (timr, flags, &new_spec, rtn)); 793 794 unlock_timer(timr, flag); 795 if (error == TIMER_RETRY) { 796 rtn = NULL; // We already got the old time... 797 goto retry; 798 } 799 800 if (old_setting && !error && 801 copy_to_user(old_setting, &old_spec, sizeof (old_spec))) 802 error = -EFAULT; 803 804 return error; 805} 806 807static inline int common_timer_del(struct k_itimer *timer) 808{ 809 timer->it.real.interval.tv64 = 0; 810 811 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0) 812 return TIMER_RETRY; 813 return 0; 814} 815 816static inline int timer_delete_hook(struct k_itimer *timer) 817{ 818 return CLOCK_DISPATCH(timer->it_clock, timer_del, (timer)); 819} 820 821/* Delete a POSIX.1b interval timer. */ 822SYSCALL_DEFINE1(timer_delete, timer_t, timer_id) 823{ 824 struct k_itimer *timer; 825 unsigned long flags; 826 827retry_delete: 828 timer = lock_timer(timer_id, &flags); 829 if (!timer) 830 return -EINVAL; 831 832 if (timer_delete_hook(timer) == TIMER_RETRY) { 833 unlock_timer(timer, flags); 834 goto retry_delete; 835 } 836 837 spin_lock(¤t->sighand->siglock); 838 list_del(&timer->list); 839 spin_unlock(¤t->sighand->siglock); 840 /* 841 * This keeps any tasks waiting on the spin lock from thinking 842 * they got something (see the lock code above). 843 */ 844 timer->it_signal = NULL; 845 846 unlock_timer(timer, flags); 847 release_posix_timer(timer, IT_ID_SET); 848 return 0; 849} 850 851/* 852 * return timer owned by the process, used by exit_itimers 853 */ 854static void itimer_delete(struct k_itimer *timer) 855{ 856 unsigned long flags; 857 858retry_delete: 859 spin_lock_irqsave(&timer->it_lock, flags); 860 861 if (timer_delete_hook(timer) == TIMER_RETRY) { 862 unlock_timer(timer, flags); 863 goto retry_delete; 864 } 865 list_del(&timer->list); 866 /* 867 * This keeps any tasks waiting on the spin lock from thinking 868 * they got something (see the lock code above). 869 */ 870 timer->it_signal = NULL; 871 872 unlock_timer(timer, flags); 873 release_posix_timer(timer, IT_ID_SET); 874} 875 876/* 877 * This is called by do_exit or de_thread, only when there are no more 878 * references to the shared signal_struct. 879 */ 880void exit_itimers(struct signal_struct *sig) 881{ 882 struct k_itimer *tmr; 883 884 while (!list_empty(&sig->posix_timers)) { 885 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list); 886 itimer_delete(tmr); 887 } 888} 889 890/* Not available / possible... functions */ 891int do_posix_clock_nosettime(const clockid_t clockid, struct timespec *tp) 892{ 893 return -EINVAL; 894} 895EXPORT_SYMBOL_GPL(do_posix_clock_nosettime); 896 897int do_posix_clock_nonanosleep(const clockid_t clock, int flags, 898 struct timespec *t, struct timespec __user *r) 899{ 900#ifndef ENOTSUP 901 return -EOPNOTSUPP; /* aka ENOTSUP in userland for POSIX */ 902#else /* parisc does define it separately. */ 903 return -ENOTSUP; 904#endif 905} 906EXPORT_SYMBOL_GPL(do_posix_clock_nonanosleep); 907 908SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock, 909 const struct timespec __user *, tp) 910{ 911 struct timespec new_tp; 912 913 if (invalid_clockid(which_clock)) 914 return -EINVAL; 915 if (copy_from_user(&new_tp, tp, sizeof (*tp))) 916 return -EFAULT; 917 918 return CLOCK_DISPATCH(which_clock, clock_set, (which_clock, &new_tp)); 919} 920 921SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock, 922 struct timespec __user *,tp) 923{ 924 struct timespec kernel_tp; 925 int error; 926 927 if (invalid_clockid(which_clock)) 928 return -EINVAL; 929 error = CLOCK_DISPATCH(which_clock, clock_get, 930 (which_clock, &kernel_tp)); 931 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp))) 932 error = -EFAULT; 933 934 return error; 935 936} 937 938SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, 939 struct timespec __user *, tp) 940{ 941 struct timespec rtn_tp; 942 int error; 943 944 if (invalid_clockid(which_clock)) 945 return -EINVAL; 946 947 error = CLOCK_DISPATCH(which_clock, clock_getres, 948 (which_clock, &rtn_tp)); 949 950 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) { 951 error = -EFAULT; 952 } 953 954 return error; 955} 956 957/* 958 * nanosleep for monotonic and realtime clocks 959 */ 960static int common_nsleep(const clockid_t which_clock, int flags, 961 struct timespec *tsave, struct timespec __user *rmtp) 962{ 963 return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ? 964 HRTIMER_MODE_ABS : HRTIMER_MODE_REL, 965 which_clock); 966} 967 968SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, 969 const struct timespec __user *, rqtp, 970 struct timespec __user *, rmtp) 971{ 972 struct timespec t; 973 974 if (invalid_clockid(which_clock)) 975 return -EINVAL; 976 977 if (copy_from_user(&t, rqtp, sizeof (struct timespec))) 978 return -EFAULT; 979 980 if (!timespec_valid(&t)) 981 return -EINVAL; 982 983 return CLOCK_DISPATCH(which_clock, nsleep, 984 (which_clock, flags, &t, rmtp)); 985} 986 987/* 988 * nanosleep_restart for monotonic and realtime clocks 989 */ 990static int common_nsleep_restart(struct restart_block *restart_block) 991{ 992 return hrtimer_nanosleep_restart(restart_block); 993} 994 995/* 996 * This will restart clock_nanosleep. This is required only by 997 * compat_clock_nanosleep_restart for now. 998 */ 999long 1000clock_nanosleep_restart(struct restart_block *restart_block) 1001{ 1002 clockid_t which_clock = restart_block->arg0; 1003 1004 return CLOCK_DISPATCH(which_clock, nsleep_restart, 1005 (restart_block)); 1006} 1007