2 * linux/kernel/time/timekeeping.c
4 * Kernel timekeeping code and accessor functions
6 * This code was moved from linux/kernel/timer.c.
7 * Please see that file for copyright and history logs.
11 #include <linux/timekeeper_internal.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include <linux/percpu.h>
15 #include <linux/init.h>
17 #include <linux/sched.h>
18 #include <linux/syscore_ops.h>
19 #include <linux/clocksource.h>
20 #include <linux/jiffies.h>
21 #include <linux/time.h>
22 #include <linux/tick.h>
23 #include <linux/stop_machine.h>
24 #include <linux/pvclock_gtod.h>
25 #include <linux/compiler.h>
27 #include "tick-internal.h"
28 #include "ntp_internal.h"
29 #include "timekeeping_internal.h"
31 #define TK_CLEAR_NTP (1 << 0)
32 #define TK_MIRROR (1 << 1)
33 #define TK_CLOCK_WAS_SET (1 << 2)
35 static struct timekeeper timekeeper;
36 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
37 static seqcount_t timekeeper_seq;
38 static struct timekeeper shadow_timekeeper;
40 /* flag for if timekeeping is suspended */
41 int __read_mostly timekeeping_suspended;
43 /* Flag for if there is a persistent clock on this platform */
44 bool __read_mostly persistent_clock_exist = false;
46 static inline void tk_normalize_xtime(struct timekeeper *tk)
48 while (tk->xtime_nsec >= ((u64)NSEC_PER_SEC << tk->shift)) {
49 tk->xtime_nsec -= (u64)NSEC_PER_SEC << tk->shift;
54 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
56 tk->xtime_sec = ts->tv_sec;
57 tk->xtime_nsec = (u64)ts->tv_nsec << tk->shift;
60 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
62 tk->xtime_sec += ts->tv_sec;
63 tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift;
64 tk_normalize_xtime(tk);
67 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
69 struct timespec64 tmp;
72 * Verify consistency of: offset_real = -wall_to_monotonic
73 * before modifying anything
75 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
76 -tk->wall_to_monotonic.tv_nsec);
77 WARN_ON_ONCE(tk->offs_real.tv64 != timespec64_to_ktime(tmp).tv64);
78 tk->wall_to_monotonic = wtm;
79 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
80 tk->offs_real = timespec64_to_ktime(tmp);
81 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
84 static void tk_set_sleep_time(struct timekeeper *tk, struct timespec64 t)
86 /* Verify consistency before modifying */
87 WARN_ON_ONCE(tk->offs_boot.tv64 != timespec64_to_ktime(tk->total_sleep_time).tv64);
89 tk->total_sleep_time = t;
90 tk->offs_boot = timespec64_to_ktime(t);
94 * tk_setup_internals - Set up internals to use clocksource clock.
96 * @tk: The target timekeeper to setup.
97 * @clock: Pointer to clocksource.
99 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
100 * pair and interval request.
102 * Unless you're the timekeeping code, you should not be using this!
104 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
107 u64 tmp, ntpinterval;
108 struct clocksource *old_clock;
110 old_clock = tk->clock;
112 tk->cycle_last = clock->cycle_last = clock->read(clock);
114 /* Do the ns -> cycle conversion first, using original mult */
115 tmp = NTP_INTERVAL_LENGTH;
116 tmp <<= clock->shift;
118 tmp += clock->mult/2;
119 do_div(tmp, clock->mult);
123 interval = (cycle_t) tmp;
124 tk->cycle_interval = interval;
126 /* Go back from cycles -> shifted ns */
127 tk->xtime_interval = (u64) interval * clock->mult;
128 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
130 ((u64) interval * clock->mult) >> clock->shift;
132 /* if changing clocks, convert xtime_nsec shift units */
134 int shift_change = clock->shift - old_clock->shift;
135 if (shift_change < 0)
136 tk->xtime_nsec >>= -shift_change;
138 tk->xtime_nsec <<= shift_change;
140 tk->shift = clock->shift;
143 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
146 * The timekeeper keeps its own mult values for the currently
147 * active clocksource. These value will be adjusted via NTP
148 * to counteract clock drifting.
150 tk->mult = clock->mult;
153 /* Timekeeper helper functions. */
155 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
156 static u32 default_arch_gettimeoffset(void) { return 0; }
157 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
159 static inline u32 arch_gettimeoffset(void) { return 0; }
162 static inline s64 timekeeping_get_ns(struct timekeeper *tk)
164 cycle_t cycle_now, cycle_delta;
165 struct clocksource *clock;
168 /* read clocksource: */
170 cycle_now = clock->read(clock);
172 /* calculate the delta since the last update_wall_time: */
173 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
175 nsec = cycle_delta * tk->mult + tk->xtime_nsec;
178 /* If arch requires, add in get_arch_timeoffset() */
179 return nsec + arch_gettimeoffset();
182 static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)
184 cycle_t cycle_now, cycle_delta;
185 struct clocksource *clock;
188 /* read clocksource: */
190 cycle_now = clock->read(clock);
192 /* calculate the delta since the last update_wall_time: */
193 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
195 /* convert delta to nanoseconds. */
196 nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
198 /* If arch requires, add in get_arch_timeoffset() */
199 return nsec + arch_gettimeoffset();
202 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
204 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
206 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
210 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
212 int pvclock_gtod_register_notifier(struct notifier_block *nb)
214 struct timekeeper *tk = &timekeeper;
218 raw_spin_lock_irqsave(&timekeeper_lock, flags);
219 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
220 update_pvclock_gtod(tk, true);
221 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
225 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
228 * pvclock_gtod_unregister_notifier - unregister a pvclock
229 * timedata update listener
231 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
236 raw_spin_lock_irqsave(&timekeeper_lock, flags);
237 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
238 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
242 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
244 /* must hold timekeeper_lock */
245 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
247 if (action & TK_CLEAR_NTP) {
252 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
254 if (action & TK_MIRROR)
255 memcpy(&shadow_timekeeper, &timekeeper, sizeof(timekeeper));
259 * timekeeping_forward_now - update clock to the current time
261 * Forward the current clock to update its state since the last call to
262 * update_wall_time(). This is useful before significant clock changes,
263 * as it avoids having to deal with this time offset explicitly.
265 static void timekeeping_forward_now(struct timekeeper *tk)
267 cycle_t cycle_now, cycle_delta;
268 struct clocksource *clock;
272 cycle_now = clock->read(clock);
273 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
274 tk->cycle_last = clock->cycle_last = cycle_now;
276 tk->xtime_nsec += cycle_delta * tk->mult;
278 /* If arch requires, add in get_arch_timeoffset() */
279 tk->xtime_nsec += (u64)arch_gettimeoffset() << tk->shift;
281 tk_normalize_xtime(tk);
283 nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
284 timespec64_add_ns(&tk->raw_time, nsec);
288 * __getnstimeofday - Returns the time of day in a timespec.
289 * @ts: pointer to the timespec to be set
291 * Updates the time of day in the timespec.
292 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
294 int __getnstimeofday(struct timespec *ts)
296 struct timekeeper *tk = &timekeeper;
301 seq = read_seqcount_begin(&timekeeper_seq);
303 ts->tv_sec = tk->xtime_sec;
304 nsecs = timekeeping_get_ns(tk);
306 } while (read_seqcount_retry(&timekeeper_seq, seq));
309 timespec_add_ns(ts, nsecs);
312 * Do not bail out early, in case there were callers still using
313 * the value, even in the face of the WARN_ON.
315 if (unlikely(timekeeping_suspended))
319 EXPORT_SYMBOL(__getnstimeofday);
322 * getnstimeofday - Returns the time of day in a timespec.
323 * @ts: pointer to the timespec to be set
325 * Returns the time of day in a timespec (WARN if suspended).
327 void getnstimeofday(struct timespec *ts)
329 WARN_ON(__getnstimeofday(ts));
331 EXPORT_SYMBOL(getnstimeofday);
333 ktime_t ktime_get(void)
335 struct timekeeper *tk = &timekeeper;
339 WARN_ON(timekeeping_suspended);
342 seq = read_seqcount_begin(&timekeeper_seq);
343 secs = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
344 nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec;
346 } while (read_seqcount_retry(&timekeeper_seq, seq));
348 return ktime_set(secs, nsecs);
350 EXPORT_SYMBOL_GPL(ktime_get);
353 * ktime_get_ts - get the monotonic clock in timespec format
354 * @ts: pointer to timespec variable
356 * The function calculates the monotonic clock from the realtime
357 * clock and the wall_to_monotonic offset and stores the result
358 * in normalized timespec format in the variable pointed to by @ts.
360 void ktime_get_ts(struct timespec *ts)
362 struct timekeeper *tk = &timekeeper;
363 struct timespec64 ts64, tomono;
367 WARN_ON(timekeeping_suspended);
370 seq = read_seqcount_begin(&timekeeper_seq);
371 ts64.tv_sec = tk->xtime_sec;
372 nsec = timekeeping_get_ns(tk);
373 tomono = tk->wall_to_monotonic;
375 } while (read_seqcount_retry(&timekeeper_seq, seq));
377 ts64.tv_sec += tomono.tv_sec;
379 timespec64_add_ns(&ts64, nsec + tomono.tv_nsec);
380 *ts = timespec64_to_timespec(ts64);
382 EXPORT_SYMBOL_GPL(ktime_get_ts);
386 * timekeeping_clocktai - Returns the TAI time of day in a timespec
387 * @ts: pointer to the timespec to be set
389 * Returns the time of day in a timespec.
391 void timekeeping_clocktai(struct timespec *ts)
393 struct timekeeper *tk = &timekeeper;
394 struct timespec64 ts64;
398 WARN_ON(timekeeping_suspended);
401 seq = read_seqcount_begin(&timekeeper_seq);
403 ts64.tv_sec = tk->xtime_sec + tk->tai_offset;
404 nsecs = timekeeping_get_ns(tk);
406 } while (read_seqcount_retry(&timekeeper_seq, seq));
409 timespec64_add_ns(&ts64, nsecs);
410 *ts = timespec64_to_timespec(ts64);
413 EXPORT_SYMBOL(timekeeping_clocktai);
417 * ktime_get_clocktai - Returns the TAI time of day in a ktime
419 * Returns the time of day in a ktime.
421 ktime_t ktime_get_clocktai(void)
425 timekeeping_clocktai(&ts);
426 return timespec_to_ktime(ts);
428 EXPORT_SYMBOL(ktime_get_clocktai);
430 #ifdef CONFIG_NTP_PPS
433 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
434 * @ts_raw: pointer to the timespec to be set to raw monotonic time
435 * @ts_real: pointer to the timespec to be set to the time of day
437 * This function reads both the time of day and raw monotonic time at the
438 * same time atomically and stores the resulting timestamps in timespec
441 void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
443 struct timekeeper *tk = &timekeeper;
445 s64 nsecs_raw, nsecs_real;
447 WARN_ON_ONCE(timekeeping_suspended);
450 seq = read_seqcount_begin(&timekeeper_seq);
452 *ts_raw = timespec64_to_timespec(tk->raw_time);
453 ts_real->tv_sec = tk->xtime_sec;
454 ts_real->tv_nsec = 0;
456 nsecs_raw = timekeeping_get_ns_raw(tk);
457 nsecs_real = timekeeping_get_ns(tk);
459 } while (read_seqcount_retry(&timekeeper_seq, seq));
461 timespec_add_ns(ts_raw, nsecs_raw);
462 timespec_add_ns(ts_real, nsecs_real);
464 EXPORT_SYMBOL(getnstime_raw_and_real);
466 #endif /* CONFIG_NTP_PPS */
469 * do_gettimeofday - Returns the time of day in a timeval
470 * @tv: pointer to the timeval to be set
472 * NOTE: Users should be converted to using getnstimeofday()
474 void do_gettimeofday(struct timeval *tv)
478 getnstimeofday(&now);
479 tv->tv_sec = now.tv_sec;
480 tv->tv_usec = now.tv_nsec/1000;
482 EXPORT_SYMBOL(do_gettimeofday);
485 * do_settimeofday - Sets the time of day
486 * @tv: pointer to the timespec variable containing the new time
488 * Sets the time of day to the new time and update NTP and notify hrtimers
490 int do_settimeofday(const struct timespec *tv)
492 struct timekeeper *tk = &timekeeper;
493 struct timespec64 ts_delta, xt, tmp;
496 if (!timespec_valid_strict(tv))
499 raw_spin_lock_irqsave(&timekeeper_lock, flags);
500 write_seqcount_begin(&timekeeper_seq);
502 timekeeping_forward_now(tk);
505 ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;
506 ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec;
508 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
510 tmp = timespec_to_timespec64(*tv);
511 tk_set_xtime(tk, &tmp);
513 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
515 write_seqcount_end(&timekeeper_seq);
516 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
518 /* signal hrtimers about time change */
523 EXPORT_SYMBOL(do_settimeofday);
526 * timekeeping_inject_offset - Adds or subtracts from the current time.
527 * @tv: pointer to the timespec variable containing the offset
529 * Adds or subtracts an offset value from the current time.
531 int timekeeping_inject_offset(struct timespec *ts)
533 struct timekeeper *tk = &timekeeper;
535 struct timespec64 ts64, tmp;
538 if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
541 ts64 = timespec_to_timespec64(*ts);
543 raw_spin_lock_irqsave(&timekeeper_lock, flags);
544 write_seqcount_begin(&timekeeper_seq);
546 timekeeping_forward_now(tk);
548 /* Make sure the proposed value is valid */
549 tmp = timespec64_add(tk_xtime(tk), ts64);
550 if (!timespec64_valid_strict(&tmp)) {
555 tk_xtime_add(tk, &ts64);
556 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
558 error: /* even if we error out, we forwarded the time, so call update */
559 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
561 write_seqcount_end(&timekeeper_seq);
562 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
564 /* signal hrtimers about time change */
569 EXPORT_SYMBOL(timekeeping_inject_offset);
573 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
576 s32 timekeeping_get_tai_offset(void)
578 struct timekeeper *tk = &timekeeper;
583 seq = read_seqcount_begin(&timekeeper_seq);
584 ret = tk->tai_offset;
585 } while (read_seqcount_retry(&timekeeper_seq, seq));
591 * __timekeeping_set_tai_offset - Lock free worker function
594 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
596 tk->tai_offset = tai_offset;
597 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
601 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
604 void timekeeping_set_tai_offset(s32 tai_offset)
606 struct timekeeper *tk = &timekeeper;
609 raw_spin_lock_irqsave(&timekeeper_lock, flags);
610 write_seqcount_begin(&timekeeper_seq);
611 __timekeeping_set_tai_offset(tk, tai_offset);
612 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
613 write_seqcount_end(&timekeeper_seq);
614 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
619 * change_clocksource - Swaps clocksources if a new one is available
621 * Accumulates current time interval and initializes new clocksource
623 static int change_clocksource(void *data)
625 struct timekeeper *tk = &timekeeper;
626 struct clocksource *new, *old;
629 new = (struct clocksource *) data;
631 raw_spin_lock_irqsave(&timekeeper_lock, flags);
632 write_seqcount_begin(&timekeeper_seq);
634 timekeeping_forward_now(tk);
636 * If the cs is in module, get a module reference. Succeeds
637 * for built-in code (owner == NULL) as well.
639 if (try_module_get(new->owner)) {
640 if (!new->enable || new->enable(new) == 0) {
642 tk_setup_internals(tk, new);
645 module_put(old->owner);
647 module_put(new->owner);
650 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
652 write_seqcount_end(&timekeeper_seq);
653 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
659 * timekeeping_notify - Install a new clock source
660 * @clock: pointer to the clock source
662 * This function is called from clocksource.c after a new, better clock
663 * source has been registered. The caller holds the clocksource_mutex.
665 int timekeeping_notify(struct clocksource *clock)
667 struct timekeeper *tk = &timekeeper;
669 if (tk->clock == clock)
671 stop_machine(change_clocksource, clock, NULL);
673 return tk->clock == clock ? 0 : -1;
677 * ktime_get_real - get the real (wall-) time in ktime_t format
679 * returns the time in ktime_t format
681 ktime_t ktime_get_real(void)
685 getnstimeofday(&now);
687 return timespec_to_ktime(now);
689 EXPORT_SYMBOL_GPL(ktime_get_real);
692 * getrawmonotonic - Returns the raw monotonic time in a timespec
693 * @ts: pointer to the timespec to be set
695 * Returns the raw monotonic time (completely un-modified by ntp)
697 void getrawmonotonic(struct timespec *ts)
699 struct timekeeper *tk = &timekeeper;
700 struct timespec64 ts64;
705 seq = read_seqcount_begin(&timekeeper_seq);
706 nsecs = timekeeping_get_ns_raw(tk);
709 } while (read_seqcount_retry(&timekeeper_seq, seq));
711 timespec64_add_ns(&ts64, nsecs);
712 *ts = timespec64_to_timespec(ts64);
714 EXPORT_SYMBOL(getrawmonotonic);
717 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
719 int timekeeping_valid_for_hres(void)
721 struct timekeeper *tk = &timekeeper;
726 seq = read_seqcount_begin(&timekeeper_seq);
728 ret = tk->clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
730 } while (read_seqcount_retry(&timekeeper_seq, seq));
736 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
738 u64 timekeeping_max_deferment(void)
740 struct timekeeper *tk = &timekeeper;
745 seq = read_seqcount_begin(&timekeeper_seq);
747 ret = tk->clock->max_idle_ns;
749 } while (read_seqcount_retry(&timekeeper_seq, seq));
755 * read_persistent_clock - Return time from the persistent clock.
757 * Weak dummy function for arches that do not yet support it.
758 * Reads the time from the battery backed persistent clock.
759 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
761 * XXX - Do be sure to remove it once all arches implement it.
763 void __weak read_persistent_clock(struct timespec *ts)
770 * read_boot_clock - Return time of the system start.
772 * Weak dummy function for arches that do not yet support it.
773 * Function to read the exact time the system has been started.
774 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
776 * XXX - Do be sure to remove it once all arches implement it.
778 void __weak read_boot_clock(struct timespec *ts)
785 * timekeeping_init - Initializes the clocksource and common timekeeping values
787 void __init timekeeping_init(void)
789 struct timekeeper *tk = &timekeeper;
790 struct clocksource *clock;
792 struct timespec64 now, boot, tmp;
795 read_persistent_clock(&ts);
796 now = timespec_to_timespec64(ts);
797 if (!timespec64_valid_strict(&now)) {
798 pr_warn("WARNING: Persistent clock returned invalid value!\n"
799 " Check your CMOS/BIOS settings.\n");
802 } else if (now.tv_sec || now.tv_nsec)
803 persistent_clock_exist = true;
805 read_boot_clock(&ts);
806 boot = timespec_to_timespec64(ts);
807 if (!timespec64_valid_strict(&boot)) {
808 pr_warn("WARNING: Boot clock returned invalid value!\n"
809 " Check your CMOS/BIOS settings.\n");
814 raw_spin_lock_irqsave(&timekeeper_lock, flags);
815 write_seqcount_begin(&timekeeper_seq);
818 clock = clocksource_default_clock();
820 clock->enable(clock);
821 tk_setup_internals(tk, clock);
823 tk_set_xtime(tk, &now);
824 tk->raw_time.tv_sec = 0;
825 tk->raw_time.tv_nsec = 0;
826 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
829 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
830 tk_set_wall_to_mono(tk, tmp);
834 tk_set_sleep_time(tk, tmp);
836 memcpy(&shadow_timekeeper, &timekeeper, sizeof(timekeeper));
838 write_seqcount_end(&timekeeper_seq);
839 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
842 /* time in seconds when suspend began */
843 static struct timespec64 timekeeping_suspend_time;
846 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
847 * @delta: pointer to a timespec delta value
849 * Takes a timespec offset measuring a suspend interval and properly
850 * adds the sleep offset to the timekeeping variables.
852 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
853 struct timespec64 *delta)
855 if (!timespec64_valid_strict(delta)) {
856 printk_deferred(KERN_WARNING
857 "__timekeeping_inject_sleeptime: Invalid "
858 "sleep delta value!\n");
861 tk_xtime_add(tk, delta);
862 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
863 tk_set_sleep_time(tk, timespec64_add(tk->total_sleep_time, *delta));
864 tk_debug_account_sleep_time(delta);
868 * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values
869 * @delta: pointer to a timespec delta value
871 * This hook is for architectures that cannot support read_persistent_clock
872 * because their RTC/persistent clock is only accessible when irqs are enabled.
874 * This function should only be called by rtc_resume(), and allows
875 * a suspend offset to be injected into the timekeeping values.
877 void timekeeping_inject_sleeptime(struct timespec *delta)
879 struct timekeeper *tk = &timekeeper;
880 struct timespec64 tmp;
884 * Make sure we don't set the clock twice, as timekeeping_resume()
887 if (has_persistent_clock())
890 raw_spin_lock_irqsave(&timekeeper_lock, flags);
891 write_seqcount_begin(&timekeeper_seq);
893 timekeeping_forward_now(tk);
895 tmp = timespec_to_timespec64(*delta);
896 __timekeeping_inject_sleeptime(tk, &tmp);
898 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
900 write_seqcount_end(&timekeeper_seq);
901 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
903 /* signal hrtimers about time change */
908 * timekeeping_resume - Resumes the generic timekeeping subsystem.
910 * This is for the generic clocksource timekeeping.
911 * xtime/wall_to_monotonic/jiffies/etc are
912 * still managed by arch specific suspend/resume code.
914 static void timekeeping_resume(void)
916 struct timekeeper *tk = &timekeeper;
917 struct clocksource *clock = tk->clock;
919 struct timespec64 ts_new, ts_delta;
921 cycle_t cycle_now, cycle_delta;
922 bool suspendtime_found = false;
924 read_persistent_clock(&tmp);
925 ts_new = timespec_to_timespec64(tmp);
927 clockevents_resume();
928 clocksource_resume();
930 raw_spin_lock_irqsave(&timekeeper_lock, flags);
931 write_seqcount_begin(&timekeeper_seq);
934 * After system resumes, we need to calculate the suspended time and
935 * compensate it for the OS time. There are 3 sources that could be
936 * used: Nonstop clocksource during suspend, persistent clock and rtc
939 * One specific platform may have 1 or 2 or all of them, and the
940 * preference will be:
941 * suspend-nonstop clocksource -> persistent clock -> rtc
942 * The less preferred source will only be tried if there is no better
943 * usable source. The rtc part is handled separately in rtc core code.
945 cycle_now = clock->read(clock);
946 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
947 cycle_now > clock->cycle_last) {
948 u64 num, max = ULLONG_MAX;
949 u32 mult = clock->mult;
950 u32 shift = clock->shift;
953 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
956 * "cycle_delta * mutl" may cause 64 bits overflow, if the
957 * suspended time is too long. In that case we need do the
958 * 64 bits math carefully
961 if (cycle_delta > max) {
962 num = div64_u64(cycle_delta, max);
963 nsec = (((u64) max * mult) >> shift) * num;
964 cycle_delta -= num * max;
966 nsec += ((u64) cycle_delta * mult) >> shift;
968 ts_delta = ns_to_timespec64(nsec);
969 suspendtime_found = true;
970 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
971 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
972 suspendtime_found = true;
975 if (suspendtime_found)
976 __timekeeping_inject_sleeptime(tk, &ts_delta);
978 /* Re-base the last cycle value */
979 tk->cycle_last = clock->cycle_last = cycle_now;
981 timekeeping_suspended = 0;
982 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
983 write_seqcount_end(&timekeeper_seq);
984 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
986 touch_softlockup_watchdog();
988 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
990 /* Resume hrtimers */
994 static int timekeeping_suspend(void)
996 struct timekeeper *tk = &timekeeper;
998 struct timespec64 delta, delta_delta;
999 static struct timespec64 old_delta;
1000 struct timespec tmp;
1002 read_persistent_clock(&tmp);
1003 timekeeping_suspend_time = timespec_to_timespec64(tmp);
1006 * On some systems the persistent_clock can not be detected at
1007 * timekeeping_init by its return value, so if we see a valid
1008 * value returned, update the persistent_clock_exists flag.
1010 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1011 persistent_clock_exist = true;
1013 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1014 write_seqcount_begin(&timekeeper_seq);
1015 timekeeping_forward_now(tk);
1016 timekeeping_suspended = 1;
1019 * To avoid drift caused by repeated suspend/resumes,
1020 * which each can add ~1 second drift error,
1021 * try to compensate so the difference in system time
1022 * and persistent_clock time stays close to constant.
1024 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1025 delta_delta = timespec64_sub(delta, old_delta);
1026 if (abs(delta_delta.tv_sec) >= 2) {
1028 * if delta_delta is too large, assume time correction
1029 * has occured and set old_delta to the current delta.
1033 /* Otherwise try to adjust old_system to compensate */
1034 timekeeping_suspend_time =
1035 timespec64_add(timekeeping_suspend_time, delta_delta);
1038 timekeeping_update(tk, TK_MIRROR);
1039 write_seqcount_end(&timekeeper_seq);
1040 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1042 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
1043 clocksource_suspend();
1044 clockevents_suspend();
1049 /* sysfs resume/suspend bits for timekeeping */
1050 static struct syscore_ops timekeeping_syscore_ops = {
1051 .resume = timekeeping_resume,
1052 .suspend = timekeeping_suspend,
1055 static int __init timekeeping_init_ops(void)
1057 register_syscore_ops(&timekeeping_syscore_ops);
1061 device_initcall(timekeeping_init_ops);
1064 * If the error is already larger, we look ahead even further
1065 * to compensate for late or lost adjustments.
1067 static __always_inline int timekeeping_bigadjust(struct timekeeper *tk,
1068 s64 error, s64 *interval,
1072 u32 look_ahead, adj;
1076 * Use the current error value to determine how much to look ahead.
1077 * The larger the error the slower we adjust for it to avoid problems
1078 * with losing too many ticks, otherwise we would overadjust and
1079 * produce an even larger error. The smaller the adjustment the
1080 * faster we try to adjust for it, as lost ticks can do less harm
1081 * here. This is tuned so that an error of about 1 msec is adjusted
1082 * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
1084 error2 = tk->ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
1085 error2 = abs(error2);
1086 for (look_ahead = 0; error2 > 0; look_ahead++)
1090 * Now calculate the error in (1 << look_ahead) ticks, but first
1091 * remove the single look ahead already included in the error.
1093 tick_error = ntp_tick_length() >> (tk->ntp_error_shift + 1);
1094 tick_error -= tk->xtime_interval >> 1;
1095 error = ((error - tick_error) >> look_ahead) + tick_error;
1097 /* Finally calculate the adjustment shift value. */
1102 *interval = -*interval;
1106 for (adj = 0; error > i; adj++)
1115 * Adjust the multiplier to reduce the error value,
1116 * this is optimized for the most common adjustments of -1,0,1,
1117 * for other values we can do a bit more work.
1119 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1121 s64 error, interval = tk->cycle_interval;
1125 * The point of this is to check if the error is greater than half
1128 * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs.
1130 * Note we subtract one in the shift, so that error is really error*2.
1131 * This "saves" dividing(shifting) interval twice, but keeps the
1132 * (error > interval) comparison as still measuring if error is
1133 * larger than half an interval.
1135 * Note: It does not "save" on aggravation when reading the code.
1137 error = tk->ntp_error >> (tk->ntp_error_shift - 1);
1138 if (error > interval) {
1140 * We now divide error by 4(via shift), which checks if
1141 * the error is greater than twice the interval.
1142 * If it is greater, we need a bigadjust, if its smaller,
1143 * we can adjust by 1.
1146 if (likely(error <= interval))
1149 adj = timekeeping_bigadjust(tk, error, &interval, &offset);
1151 if (error < -interval) {
1152 /* See comment above, this is just switched for the negative */
1154 if (likely(error >= -interval)) {
1156 interval = -interval;
1159 adj = timekeeping_bigadjust(tk, error, &interval, &offset);
1166 if (unlikely(tk->clock->maxadj &&
1167 (tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) {
1168 printk_deferred_once(KERN_WARNING
1169 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1170 tk->clock->name, (long)tk->mult + adj,
1171 (long)tk->clock->mult + tk->clock->maxadj);
1174 * So the following can be confusing.
1176 * To keep things simple, lets assume adj == 1 for now.
1178 * When adj != 1, remember that the interval and offset values
1179 * have been appropriately scaled so the math is the same.
1181 * The basic idea here is that we're increasing the multiplier
1182 * by one, this causes the xtime_interval to be incremented by
1183 * one cycle_interval. This is because:
1184 * xtime_interval = cycle_interval * mult
1185 * So if mult is being incremented by one:
1186 * xtime_interval = cycle_interval * (mult + 1)
1188 * xtime_interval = (cycle_interval * mult) + cycle_interval
1189 * Which can be shortened to:
1190 * xtime_interval += cycle_interval
1192 * So offset stores the non-accumulated cycles. Thus the current
1193 * time (in shifted nanoseconds) is:
1194 * now = (offset * adj) + xtime_nsec
1195 * Now, even though we're adjusting the clock frequency, we have
1196 * to keep time consistent. In other words, we can't jump back
1197 * in time, and we also want to avoid jumping forward in time.
1199 * So given the same offset value, we need the time to be the same
1200 * both before and after the freq adjustment.
1201 * now = (offset * adj_1) + xtime_nsec_1
1202 * now = (offset * adj_2) + xtime_nsec_2
1204 * (offset * adj_1) + xtime_nsec_1 =
1205 * (offset * adj_2) + xtime_nsec_2
1209 * (offset * adj_1) + xtime_nsec_1 =
1210 * (offset * (adj_1+1)) + xtime_nsec_2
1211 * (offset * adj_1) + xtime_nsec_1 =
1212 * (offset * adj_1) + offset + xtime_nsec_2
1213 * Canceling the sides:
1214 * xtime_nsec_1 = offset + xtime_nsec_2
1216 * xtime_nsec_2 = xtime_nsec_1 - offset
1217 * Which simplfies to:
1218 * xtime_nsec -= offset
1220 * XXX - TODO: Doc ntp_error calculation.
1223 tk->xtime_interval += interval;
1224 tk->xtime_nsec -= offset;
1225 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1229 * It may be possible that when we entered this function, xtime_nsec
1230 * was very small. Further, if we're slightly speeding the clocksource
1231 * in the code above, its possible the required corrective factor to
1232 * xtime_nsec could cause it to underflow.
1234 * Now, since we already accumulated the second, cannot simply roll
1235 * the accumulated second back, since the NTP subsystem has been
1236 * notified via second_overflow. So instead we push xtime_nsec forward
1237 * by the amount we underflowed, and add that amount into the error.
1239 * We'll correct this error next time through this function, when
1240 * xtime_nsec is not as small.
1242 if (unlikely((s64)tk->xtime_nsec < 0)) {
1243 s64 neg = -(s64)tk->xtime_nsec;
1245 tk->ntp_error += neg << tk->ntp_error_shift;
1251 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1253 * Helper function that accumulates a the nsecs greater then a second
1254 * from the xtime_nsec field to the xtime_secs field.
1255 * It also calls into the NTP code to handle leapsecond processing.
1258 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1260 u64 nsecps = (u64)NSEC_PER_SEC << tk->shift;
1261 unsigned int clock_set = 0;
1263 while (tk->xtime_nsec >= nsecps) {
1266 tk->xtime_nsec -= nsecps;
1269 /* Figure out if its a leap sec and apply if needed */
1270 leap = second_overflow(tk->xtime_sec);
1271 if (unlikely(leap)) {
1272 struct timespec64 ts;
1274 tk->xtime_sec += leap;
1278 tk_set_wall_to_mono(tk,
1279 timespec64_sub(tk->wall_to_monotonic, ts));
1281 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1283 clock_set = TK_CLOCK_WAS_SET;
1290 * logarithmic_accumulation - shifted accumulation of cycles
1292 * This functions accumulates a shifted interval of cycles into
1293 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1296 * Returns the unconsumed cycles.
1298 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
1300 unsigned int *clock_set)
1302 cycle_t interval = tk->cycle_interval << shift;
1305 /* If the offset is smaller then a shifted interval, do nothing */
1306 if (offset < interval)
1309 /* Accumulate one shifted interval */
1311 tk->cycle_last += interval;
1313 tk->xtime_nsec += tk->xtime_interval << shift;
1314 *clock_set |= accumulate_nsecs_to_secs(tk);
1316 /* Accumulate raw time */
1317 raw_nsecs = (u64)tk->raw_interval << shift;
1318 raw_nsecs += tk->raw_time.tv_nsec;
1319 if (raw_nsecs >= NSEC_PER_SEC) {
1320 u64 raw_secs = raw_nsecs;
1321 raw_nsecs = do_div(raw_secs, NSEC_PER_SEC);
1322 tk->raw_time.tv_sec += raw_secs;
1324 tk->raw_time.tv_nsec = raw_nsecs;
1326 /* Accumulate error between NTP and clock interval */
1327 tk->ntp_error += ntp_tick_length() << shift;
1328 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
1329 (tk->ntp_error_shift + shift);
1334 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
1335 static inline void old_vsyscall_fixup(struct timekeeper *tk)
1340 * Store only full nanoseconds into xtime_nsec after rounding
1341 * it up and add the remainder to the error difference.
1342 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
1343 * by truncating the remainder in vsyscalls. However, it causes
1344 * additional work to be done in timekeeping_adjust(). Once
1345 * the vsyscall implementations are converted to use xtime_nsec
1346 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
1347 * users are removed, this can be killed.
1349 remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1);
1350 tk->xtime_nsec -= remainder;
1351 tk->xtime_nsec += 1ULL << tk->shift;
1352 tk->ntp_error += remainder << tk->ntp_error_shift;
1353 tk->ntp_error -= (1ULL << tk->shift) << tk->ntp_error_shift;
1356 #define old_vsyscall_fixup(tk)
1362 * update_wall_time - Uses the current clocksource to increment the wall time
1365 void update_wall_time(void)
1367 struct clocksource *clock;
1368 struct timekeeper *real_tk = &timekeeper;
1369 struct timekeeper *tk = &shadow_timekeeper;
1371 int shift = 0, maxshift;
1372 unsigned int clock_set = 0;
1373 unsigned long flags;
1375 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1377 /* Make sure we're fully resumed: */
1378 if (unlikely(timekeeping_suspended))
1381 clock = real_tk->clock;
1383 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1384 offset = real_tk->cycle_interval;
1386 offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
1389 /* Check if there's really nothing to do */
1390 if (offset < real_tk->cycle_interval)
1394 * With NO_HZ we may have to accumulate many cycle_intervals
1395 * (think "ticks") worth of time at once. To do this efficiently,
1396 * we calculate the largest doubling multiple of cycle_intervals
1397 * that is smaller than the offset. We then accumulate that
1398 * chunk in one go, and then try to consume the next smaller
1401 shift = ilog2(offset) - ilog2(tk->cycle_interval);
1402 shift = max(0, shift);
1403 /* Bound shift to one less than what overflows tick_length */
1404 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
1405 shift = min(shift, maxshift);
1406 while (offset >= tk->cycle_interval) {
1407 offset = logarithmic_accumulation(tk, offset, shift,
1409 if (offset < tk->cycle_interval<<shift)
1413 /* correct the clock when NTP error is too big */
1414 timekeeping_adjust(tk, offset);
1417 * XXX This can be killed once everyone converts
1418 * to the new update_vsyscall.
1420 old_vsyscall_fixup(tk);
1423 * Finally, make sure that after the rounding
1424 * xtime_nsec isn't larger than NSEC_PER_SEC
1426 clock_set |= accumulate_nsecs_to_secs(tk);
1428 write_seqcount_begin(&timekeeper_seq);
1429 /* Update clock->cycle_last with the new value */
1430 clock->cycle_last = tk->cycle_last;
1432 * Update the real timekeeper.
1434 * We could avoid this memcpy by switching pointers, but that
1435 * requires changes to all other timekeeper usage sites as
1436 * well, i.e. move the timekeeper pointer getter into the
1437 * spinlocked/seqcount protected sections. And we trade this
1438 * memcpy under the timekeeper_seq against one before we start
1441 memcpy(real_tk, tk, sizeof(*tk));
1442 timekeeping_update(real_tk, clock_set);
1443 write_seqcount_end(&timekeeper_seq);
1445 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1447 /* Have to call _delayed version, since in irq context*/
1448 clock_was_set_delayed();
1452 * getboottime - Return the real time of system boot.
1453 * @ts: pointer to the timespec to be set
1455 * Returns the wall-time of boot in a timespec.
1457 * This is based on the wall_to_monotonic offset and the total suspend
1458 * time. Calls to settimeofday will affect the value returned (which
1459 * basically means that however wrong your real time clock is at boot time,
1460 * you get the right time here).
1462 void getboottime(struct timespec *ts)
1464 struct timekeeper *tk = &timekeeper;
1465 struct timespec boottime = {
1466 .tv_sec = tk->wall_to_monotonic.tv_sec +
1467 tk->total_sleep_time.tv_sec,
1468 .tv_nsec = tk->wall_to_monotonic.tv_nsec +
1469 tk->total_sleep_time.tv_nsec
1472 set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec);
1474 EXPORT_SYMBOL_GPL(getboottime);
1477 * get_monotonic_boottime - Returns monotonic time since boot
1478 * @ts: pointer to the timespec to be set
1480 * Returns the monotonic time since boot in a timespec.
1482 * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also
1483 * includes the time spent in suspend.
1485 void get_monotonic_boottime(struct timespec *ts)
1487 struct timekeeper *tk = &timekeeper;
1488 struct timespec64 tomono, sleep, ret;
1492 WARN_ON(timekeeping_suspended);
1495 seq = read_seqcount_begin(&timekeeper_seq);
1496 ret.tv_sec = tk->xtime_sec;
1497 nsec = timekeeping_get_ns(tk);
1498 tomono = tk->wall_to_monotonic;
1499 sleep = tk->total_sleep_time;
1501 } while (read_seqcount_retry(&timekeeper_seq, seq));
1503 ret.tv_sec += tomono.tv_sec + sleep.tv_sec;
1505 timespec64_add_ns(&ret, nsec + tomono.tv_nsec + sleep.tv_nsec);
1506 *ts = timespec64_to_timespec(ret);
1508 EXPORT_SYMBOL_GPL(get_monotonic_boottime);
1511 * ktime_get_boottime - Returns monotonic time since boot in a ktime
1513 * Returns the monotonic time since boot in a ktime
1515 * This is similar to CLOCK_MONTONIC/ktime_get, but also
1516 * includes the time spent in suspend.
1518 ktime_t ktime_get_boottime(void)
1522 get_monotonic_boottime(&ts);
1523 return timespec_to_ktime(ts);
1525 EXPORT_SYMBOL_GPL(ktime_get_boottime);
1528 * monotonic_to_bootbased - Convert the monotonic time to boot based.
1529 * @ts: pointer to the timespec to be converted
1531 void monotonic_to_bootbased(struct timespec *ts)
1533 struct timekeeper *tk = &timekeeper;
1534 struct timespec64 ts64;
1536 ts64 = timespec_to_timespec64(*ts);
1537 ts64 = timespec64_add(ts64, tk->total_sleep_time);
1538 *ts = timespec64_to_timespec(ts64);
1540 EXPORT_SYMBOL_GPL(monotonic_to_bootbased);
1542 unsigned long get_seconds(void)
1544 struct timekeeper *tk = &timekeeper;
1546 return tk->xtime_sec;
1548 EXPORT_SYMBOL(get_seconds);
1550 struct timespec __current_kernel_time(void)
1552 struct timekeeper *tk = &timekeeper;
1554 return timespec64_to_timespec(tk_xtime(tk));
1557 struct timespec current_kernel_time(void)
1559 struct timekeeper *tk = &timekeeper;
1560 struct timespec64 now;
1564 seq = read_seqcount_begin(&timekeeper_seq);
1567 } while (read_seqcount_retry(&timekeeper_seq, seq));
1569 return timespec64_to_timespec(now);
1571 EXPORT_SYMBOL(current_kernel_time);
1573 struct timespec get_monotonic_coarse(void)
1575 struct timekeeper *tk = &timekeeper;
1576 struct timespec64 now, mono;
1580 seq = read_seqcount_begin(&timekeeper_seq);
1583 mono = tk->wall_to_monotonic;
1584 } while (read_seqcount_retry(&timekeeper_seq, seq));
1586 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
1587 now.tv_nsec + mono.tv_nsec);
1589 return timespec64_to_timespec(now);
1593 * Must hold jiffies_lock
1595 void do_timer(unsigned long ticks)
1597 jiffies_64 += ticks;
1598 calc_global_load(ticks);
1602 * ktime_get_update_offsets_tick - hrtimer helper
1603 * @offs_real: pointer to storage for monotonic -> realtime offset
1604 * @offs_boot: pointer to storage for monotonic -> boottime offset
1605 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1607 * Returns monotonic time at last tick and various offsets
1609 ktime_t ktime_get_update_offsets_tick(ktime_t *offs_real, ktime_t *offs_boot,
1612 struct timekeeper *tk = &timekeeper;
1613 struct timespec64 ts;
1618 seq = read_seqcount_begin(&timekeeper_seq);
1621 *offs_real = tk->offs_real;
1622 *offs_boot = tk->offs_boot;
1623 *offs_tai = tk->offs_tai;
1624 } while (read_seqcount_retry(&timekeeper_seq, seq));
1626 now = ktime_set(ts.tv_sec, ts.tv_nsec);
1627 now = ktime_sub(now, *offs_real);
1631 #ifdef CONFIG_HIGH_RES_TIMERS
1633 * ktime_get_update_offsets_now - hrtimer helper
1634 * @offs_real: pointer to storage for monotonic -> realtime offset
1635 * @offs_boot: pointer to storage for monotonic -> boottime offset
1636 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1638 * Returns current monotonic time and updates the offsets
1639 * Called from hrtimer_interrupt() or retrigger_next_event()
1641 ktime_t ktime_get_update_offsets_now(ktime_t *offs_real, ktime_t *offs_boot,
1644 struct timekeeper *tk = &timekeeper;
1650 seq = read_seqcount_begin(&timekeeper_seq);
1652 secs = tk->xtime_sec;
1653 nsecs = timekeeping_get_ns(tk);
1655 *offs_real = tk->offs_real;
1656 *offs_boot = tk->offs_boot;
1657 *offs_tai = tk->offs_tai;
1658 } while (read_seqcount_retry(&timekeeper_seq, seq));
1660 now = ktime_add_ns(ktime_set(secs, 0), nsecs);
1661 now = ktime_sub(now, *offs_real);
1667 * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format
1669 ktime_t ktime_get_monotonic_offset(void)
1671 struct timekeeper *tk = &timekeeper;
1673 struct timespec64 wtom;
1676 seq = read_seqcount_begin(&timekeeper_seq);
1677 wtom = tk->wall_to_monotonic;
1678 } while (read_seqcount_retry(&timekeeper_seq, seq));
1680 return timespec64_to_ktime(wtom);
1682 EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset);
1685 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1687 int do_adjtimex(struct timex *txc)
1689 struct timekeeper *tk = &timekeeper;
1690 unsigned long flags;
1691 struct timespec64 ts;
1692 struct timespec tmp;
1696 /* Validate the data before disabling interrupts */
1697 ret = ntp_validate_timex(txc);
1701 if (txc->modes & ADJ_SETOFFSET) {
1702 struct timespec delta;
1703 delta.tv_sec = txc->time.tv_sec;
1704 delta.tv_nsec = txc->time.tv_usec;
1705 if (!(txc->modes & ADJ_NANO))
1706 delta.tv_nsec *= 1000;
1707 ret = timekeeping_inject_offset(&delta);
1712 getnstimeofday(&tmp);
1713 ts = timespec_to_timespec64(tmp);
1715 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1716 write_seqcount_begin(&timekeeper_seq);
1718 orig_tai = tai = tk->tai_offset;
1719 ret = __do_adjtimex(txc, &ts, &tai);
1721 if (tai != orig_tai) {
1722 __timekeeping_set_tai_offset(tk, tai);
1723 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1725 write_seqcount_end(&timekeeper_seq);
1726 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1728 if (tai != orig_tai)
1731 ntp_notify_cmos_timer();
1736 #ifdef CONFIG_NTP_PPS
1738 * hardpps() - Accessor function to NTP __hardpps function
1740 void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
1742 unsigned long flags;
1744 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1745 write_seqcount_begin(&timekeeper_seq);
1747 __hardpps(phase_ts, raw_ts);
1749 write_seqcount_end(&timekeeper_seq);
1750 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1752 EXPORT_SYMBOL(hardpps);
1756 * xtime_update() - advances the timekeeping infrastructure
1757 * @ticks: number of ticks, that have elapsed since the last call.
1759 * Must be called with interrupts disabled.
1761 void xtime_update(unsigned long ticks)
1763 write_seqlock(&jiffies_lock);
1765 write_sequnlock(&jiffies_lock);