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)
36 * The most important data for readout fits into a single 64 byte
41 struct timekeeper timekeeper;
42 } tk_core ____cacheline_aligned;
44 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
45 static struct timekeeper shadow_timekeeper;
47 /* flag for if timekeeping is suspended */
48 int __read_mostly timekeeping_suspended;
50 /* Flag for if there is a persistent clock on this platform */
51 bool __read_mostly persistent_clock_exist = false;
53 static inline void tk_normalize_xtime(struct timekeeper *tk)
55 while (tk->xtime_nsec >= ((u64)NSEC_PER_SEC << tk->shift)) {
56 tk->xtime_nsec -= (u64)NSEC_PER_SEC << tk->shift;
61 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
65 ts.tv_sec = tk->xtime_sec;
66 ts.tv_nsec = (long)(tk->xtime_nsec >> tk->shift);
70 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
72 tk->xtime_sec = ts->tv_sec;
73 tk->xtime_nsec = (u64)ts->tv_nsec << tk->shift;
76 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
78 tk->xtime_sec += ts->tv_sec;
79 tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift;
80 tk_normalize_xtime(tk);
83 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
85 struct timespec64 tmp;
88 * Verify consistency of: offset_real = -wall_to_monotonic
89 * before modifying anything
91 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
92 -tk->wall_to_monotonic.tv_nsec);
93 WARN_ON_ONCE(tk->offs_real.tv64 != timespec64_to_ktime(tmp).tv64);
94 tk->wall_to_monotonic = wtm;
95 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
96 tk->offs_real = timespec64_to_ktime(tmp);
97 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
100 static void tk_set_sleep_time(struct timekeeper *tk, struct timespec64 t)
102 /* Verify consistency before modifying */
103 WARN_ON_ONCE(tk->offs_boot.tv64 != timespec64_to_ktime(tk->total_sleep_time).tv64);
105 tk->total_sleep_time = t;
106 tk->offs_boot = timespec64_to_ktime(t);
110 * tk_setup_internals - Set up internals to use clocksource clock.
112 * @tk: The target timekeeper to setup.
113 * @clock: Pointer to clocksource.
115 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
116 * pair and interval request.
118 * Unless you're the timekeeping code, you should not be using this!
120 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
123 u64 tmp, ntpinterval;
124 struct clocksource *old_clock;
126 old_clock = tk->clock;
128 tk->cycle_last = clock->cycle_last = clock->read(clock);
130 /* Do the ns -> cycle conversion first, using original mult */
131 tmp = NTP_INTERVAL_LENGTH;
132 tmp <<= clock->shift;
134 tmp += clock->mult/2;
135 do_div(tmp, clock->mult);
139 interval = (cycle_t) tmp;
140 tk->cycle_interval = interval;
142 /* Go back from cycles -> shifted ns */
143 tk->xtime_interval = (u64) interval * clock->mult;
144 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
146 ((u64) interval * clock->mult) >> clock->shift;
148 /* if changing clocks, convert xtime_nsec shift units */
150 int shift_change = clock->shift - old_clock->shift;
151 if (shift_change < 0)
152 tk->xtime_nsec >>= -shift_change;
154 tk->xtime_nsec <<= shift_change;
156 tk->shift = clock->shift;
159 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
162 * The timekeeper keeps its own mult values for the currently
163 * active clocksource. These value will be adjusted via NTP
164 * to counteract clock drifting.
166 tk->mult = clock->mult;
169 /* Timekeeper helper functions. */
171 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
172 static u32 default_arch_gettimeoffset(void) { return 0; }
173 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
175 static inline u32 arch_gettimeoffset(void) { return 0; }
178 static inline s64 timekeeping_get_ns(struct timekeeper *tk)
180 cycle_t cycle_now, cycle_delta;
181 struct clocksource *clock;
184 /* read clocksource: */
186 cycle_now = clock->read(clock);
188 /* calculate the delta since the last update_wall_time: */
189 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
191 nsec = cycle_delta * tk->mult + tk->xtime_nsec;
194 /* If arch requires, add in get_arch_timeoffset() */
195 return nsec + arch_gettimeoffset();
198 static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)
200 cycle_t cycle_now, cycle_delta;
201 struct clocksource *clock;
204 /* read clocksource: */
206 cycle_now = clock->read(clock);
208 /* calculate the delta since the last update_wall_time: */
209 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
211 /* convert delta to nanoseconds. */
212 nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
214 /* If arch requires, add in get_arch_timeoffset() */
215 return nsec + arch_gettimeoffset();
218 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
220 static inline void update_vsyscall(struct timekeeper *tk)
225 update_vsyscall_old(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult);
228 static inline void old_vsyscall_fixup(struct timekeeper *tk)
233 * Store only full nanoseconds into xtime_nsec after rounding
234 * it up and add the remainder to the error difference.
235 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
236 * by truncating the remainder in vsyscalls. However, it causes
237 * additional work to be done in timekeeping_adjust(). Once
238 * the vsyscall implementations are converted to use xtime_nsec
239 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
240 * users are removed, this can be killed.
242 remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1);
243 tk->xtime_nsec -= remainder;
244 tk->xtime_nsec += 1ULL << tk->shift;
245 tk->ntp_error += remainder << tk->ntp_error_shift;
246 tk->ntp_error -= (1ULL << tk->shift) << tk->ntp_error_shift;
249 #define old_vsyscall_fixup(tk)
252 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
254 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
256 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
260 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
262 int pvclock_gtod_register_notifier(struct notifier_block *nb)
264 struct timekeeper *tk = &tk_core.timekeeper;
268 raw_spin_lock_irqsave(&timekeeper_lock, flags);
269 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
270 update_pvclock_gtod(tk, true);
271 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
275 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
278 * pvclock_gtod_unregister_notifier - unregister a pvclock
279 * timedata update listener
281 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
286 raw_spin_lock_irqsave(&timekeeper_lock, flags);
287 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
288 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
292 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
295 * Update the ktime_t based scalar nsec members of the timekeeper
297 static inline void tk_update_ktime_data(struct timekeeper *tk)
302 * The xtime based monotonic readout is:
303 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
304 * The ktime based monotonic readout is:
305 * nsec = base_mono + now();
306 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
308 nsec = (s64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
309 nsec *= NSEC_PER_SEC;
310 nsec += tk->wall_to_monotonic.tv_nsec;
311 tk->base_mono = ns_to_ktime(nsec);
314 /* must hold timekeeper_lock */
315 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
317 if (action & TK_CLEAR_NTP) {
322 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
324 tk_update_ktime_data(tk);
326 if (action & TK_MIRROR)
327 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
328 sizeof(tk_core.timekeeper));
332 * timekeeping_forward_now - update clock to the current time
334 * Forward the current clock to update its state since the last call to
335 * update_wall_time(). This is useful before significant clock changes,
336 * as it avoids having to deal with this time offset explicitly.
338 static void timekeeping_forward_now(struct timekeeper *tk)
340 cycle_t cycle_now, cycle_delta;
341 struct clocksource *clock;
345 cycle_now = clock->read(clock);
346 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
347 tk->cycle_last = clock->cycle_last = cycle_now;
349 tk->xtime_nsec += cycle_delta * tk->mult;
351 /* If arch requires, add in get_arch_timeoffset() */
352 tk->xtime_nsec += (u64)arch_gettimeoffset() << tk->shift;
354 tk_normalize_xtime(tk);
356 nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
357 timespec64_add_ns(&tk->raw_time, nsec);
361 * __getnstimeofday64 - Returns the time of day in a timespec64.
362 * @ts: pointer to the timespec to be set
364 * Updates the time of day in the timespec.
365 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
367 int __getnstimeofday64(struct timespec64 *ts)
369 struct timekeeper *tk = &tk_core.timekeeper;
374 seq = read_seqcount_begin(&tk_core.seq);
376 ts->tv_sec = tk->xtime_sec;
377 nsecs = timekeeping_get_ns(tk);
379 } while (read_seqcount_retry(&tk_core.seq, seq));
382 timespec64_add_ns(ts, nsecs);
385 * Do not bail out early, in case there were callers still using
386 * the value, even in the face of the WARN_ON.
388 if (unlikely(timekeeping_suspended))
392 EXPORT_SYMBOL(__getnstimeofday64);
395 * getnstimeofday64 - Returns the time of day in a timespec64.
396 * @ts: pointer to the timespec to be set
398 * Returns the time of day in a timespec (WARN if suspended).
400 void getnstimeofday64(struct timespec64 *ts)
402 WARN_ON(__getnstimeofday64(ts));
404 EXPORT_SYMBOL(getnstimeofday64);
406 ktime_t ktime_get(void)
408 struct timekeeper *tk = &tk_core.timekeeper;
413 WARN_ON(timekeeping_suspended);
416 seq = read_seqcount_begin(&tk_core.seq);
417 base = tk->base_mono;
418 nsecs = timekeeping_get_ns(tk);
420 } while (read_seqcount_retry(&tk_core.seq, seq));
422 return ktime_add_ns(base, nsecs);
424 EXPORT_SYMBOL_GPL(ktime_get);
427 * ktime_get_ts64 - get the monotonic clock in timespec64 format
428 * @ts: pointer to timespec variable
430 * The function calculates the monotonic clock from the realtime
431 * clock and the wall_to_monotonic offset and stores the result
432 * in normalized timespec format in the variable pointed to by @ts.
434 void ktime_get_ts64(struct timespec64 *ts)
436 struct timekeeper *tk = &tk_core.timekeeper;
437 struct timespec64 tomono;
441 WARN_ON(timekeeping_suspended);
444 seq = read_seqcount_begin(&tk_core.seq);
445 ts->tv_sec = tk->xtime_sec;
446 nsec = timekeeping_get_ns(tk);
447 tomono = tk->wall_to_monotonic;
449 } while (read_seqcount_retry(&tk_core.seq, seq));
451 ts->tv_sec += tomono.tv_sec;
453 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
455 EXPORT_SYMBOL_GPL(ktime_get_ts64);
459 * timekeeping_clocktai - Returns the TAI time of day in a timespec
460 * @ts: pointer to the timespec to be set
462 * Returns the time of day in a timespec.
464 void timekeeping_clocktai(struct timespec *ts)
466 struct timekeeper *tk = &tk_core.timekeeper;
467 struct timespec64 ts64;
471 WARN_ON(timekeeping_suspended);
474 seq = read_seqcount_begin(&tk_core.seq);
476 ts64.tv_sec = tk->xtime_sec + tk->tai_offset;
477 nsecs = timekeeping_get_ns(tk);
479 } while (read_seqcount_retry(&tk_core.seq, seq));
482 timespec64_add_ns(&ts64, nsecs);
483 *ts = timespec64_to_timespec(ts64);
486 EXPORT_SYMBOL(timekeeping_clocktai);
490 * ktime_get_clocktai - Returns the TAI time of day in a ktime
492 * Returns the time of day in a ktime.
494 ktime_t ktime_get_clocktai(void)
498 timekeeping_clocktai(&ts);
499 return timespec_to_ktime(ts);
501 EXPORT_SYMBOL(ktime_get_clocktai);
503 #ifdef CONFIG_NTP_PPS
506 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
507 * @ts_raw: pointer to the timespec to be set to raw monotonic time
508 * @ts_real: pointer to the timespec to be set to the time of day
510 * This function reads both the time of day and raw monotonic time at the
511 * same time atomically and stores the resulting timestamps in timespec
514 void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
516 struct timekeeper *tk = &tk_core.timekeeper;
518 s64 nsecs_raw, nsecs_real;
520 WARN_ON_ONCE(timekeeping_suspended);
523 seq = read_seqcount_begin(&tk_core.seq);
525 *ts_raw = timespec64_to_timespec(tk->raw_time);
526 ts_real->tv_sec = tk->xtime_sec;
527 ts_real->tv_nsec = 0;
529 nsecs_raw = timekeeping_get_ns_raw(tk);
530 nsecs_real = timekeeping_get_ns(tk);
532 } while (read_seqcount_retry(&tk_core.seq, seq));
534 timespec_add_ns(ts_raw, nsecs_raw);
535 timespec_add_ns(ts_real, nsecs_real);
537 EXPORT_SYMBOL(getnstime_raw_and_real);
539 #endif /* CONFIG_NTP_PPS */
542 * do_gettimeofday - Returns the time of day in a timeval
543 * @tv: pointer to the timeval to be set
545 * NOTE: Users should be converted to using getnstimeofday()
547 void do_gettimeofday(struct timeval *tv)
549 struct timespec64 now;
551 getnstimeofday64(&now);
552 tv->tv_sec = now.tv_sec;
553 tv->tv_usec = now.tv_nsec/1000;
555 EXPORT_SYMBOL(do_gettimeofday);
558 * do_settimeofday - Sets the time of day
559 * @tv: pointer to the timespec variable containing the new time
561 * Sets the time of day to the new time and update NTP and notify hrtimers
563 int do_settimeofday(const struct timespec *tv)
565 struct timekeeper *tk = &tk_core.timekeeper;
566 struct timespec64 ts_delta, xt, tmp;
569 if (!timespec_valid_strict(tv))
572 raw_spin_lock_irqsave(&timekeeper_lock, flags);
573 write_seqcount_begin(&tk_core.seq);
575 timekeeping_forward_now(tk);
578 ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;
579 ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec;
581 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
583 tmp = timespec_to_timespec64(*tv);
584 tk_set_xtime(tk, &tmp);
586 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
588 write_seqcount_end(&tk_core.seq);
589 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
591 /* signal hrtimers about time change */
596 EXPORT_SYMBOL(do_settimeofday);
599 * timekeeping_inject_offset - Adds or subtracts from the current time.
600 * @tv: pointer to the timespec variable containing the offset
602 * Adds or subtracts an offset value from the current time.
604 int timekeeping_inject_offset(struct timespec *ts)
606 struct timekeeper *tk = &tk_core.timekeeper;
608 struct timespec64 ts64, tmp;
611 if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
614 ts64 = timespec_to_timespec64(*ts);
616 raw_spin_lock_irqsave(&timekeeper_lock, flags);
617 write_seqcount_begin(&tk_core.seq);
619 timekeeping_forward_now(tk);
621 /* Make sure the proposed value is valid */
622 tmp = timespec64_add(tk_xtime(tk), ts64);
623 if (!timespec64_valid_strict(&tmp)) {
628 tk_xtime_add(tk, &ts64);
629 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
631 error: /* even if we error out, we forwarded the time, so call update */
632 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
634 write_seqcount_end(&tk_core.seq);
635 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
637 /* signal hrtimers about time change */
642 EXPORT_SYMBOL(timekeeping_inject_offset);
646 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
649 s32 timekeeping_get_tai_offset(void)
651 struct timekeeper *tk = &tk_core.timekeeper;
656 seq = read_seqcount_begin(&tk_core.seq);
657 ret = tk->tai_offset;
658 } while (read_seqcount_retry(&tk_core.seq, seq));
664 * __timekeeping_set_tai_offset - Lock free worker function
667 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
669 tk->tai_offset = tai_offset;
670 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
674 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
677 void timekeeping_set_tai_offset(s32 tai_offset)
679 struct timekeeper *tk = &tk_core.timekeeper;
682 raw_spin_lock_irqsave(&timekeeper_lock, flags);
683 write_seqcount_begin(&tk_core.seq);
684 __timekeeping_set_tai_offset(tk, tai_offset);
685 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
686 write_seqcount_end(&tk_core.seq);
687 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
692 * change_clocksource - Swaps clocksources if a new one is available
694 * Accumulates current time interval and initializes new clocksource
696 static int change_clocksource(void *data)
698 struct timekeeper *tk = &tk_core.timekeeper;
699 struct clocksource *new, *old;
702 new = (struct clocksource *) data;
704 raw_spin_lock_irqsave(&timekeeper_lock, flags);
705 write_seqcount_begin(&tk_core.seq);
707 timekeeping_forward_now(tk);
709 * If the cs is in module, get a module reference. Succeeds
710 * for built-in code (owner == NULL) as well.
712 if (try_module_get(new->owner)) {
713 if (!new->enable || new->enable(new) == 0) {
715 tk_setup_internals(tk, new);
718 module_put(old->owner);
720 module_put(new->owner);
723 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
725 write_seqcount_end(&tk_core.seq);
726 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
732 * timekeeping_notify - Install a new clock source
733 * @clock: pointer to the clock source
735 * This function is called from clocksource.c after a new, better clock
736 * source has been registered. The caller holds the clocksource_mutex.
738 int timekeeping_notify(struct clocksource *clock)
740 struct timekeeper *tk = &tk_core.timekeeper;
742 if (tk->clock == clock)
744 stop_machine(change_clocksource, clock, NULL);
746 return tk->clock == clock ? 0 : -1;
750 * ktime_get_real - get the real (wall-) time in ktime_t format
752 * returns the time in ktime_t format
754 ktime_t ktime_get_real(void)
756 struct timespec64 now;
758 getnstimeofday64(&now);
760 return timespec64_to_ktime(now);
762 EXPORT_SYMBOL_GPL(ktime_get_real);
765 * getrawmonotonic - Returns the raw monotonic time in a timespec
766 * @ts: pointer to the timespec to be set
768 * Returns the raw monotonic time (completely un-modified by ntp)
770 void getrawmonotonic(struct timespec *ts)
772 struct timekeeper *tk = &tk_core.timekeeper;
773 struct timespec64 ts64;
778 seq = read_seqcount_begin(&tk_core.seq);
779 nsecs = timekeeping_get_ns_raw(tk);
782 } while (read_seqcount_retry(&tk_core.seq, seq));
784 timespec64_add_ns(&ts64, nsecs);
785 *ts = timespec64_to_timespec(ts64);
787 EXPORT_SYMBOL(getrawmonotonic);
790 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
792 int timekeeping_valid_for_hres(void)
794 struct timekeeper *tk = &tk_core.timekeeper;
799 seq = read_seqcount_begin(&tk_core.seq);
801 ret = tk->clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
803 } while (read_seqcount_retry(&tk_core.seq, seq));
809 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
811 u64 timekeeping_max_deferment(void)
813 struct timekeeper *tk = &tk_core.timekeeper;
818 seq = read_seqcount_begin(&tk_core.seq);
820 ret = tk->clock->max_idle_ns;
822 } while (read_seqcount_retry(&tk_core.seq, seq));
828 * read_persistent_clock - Return time from the persistent clock.
830 * Weak dummy function for arches that do not yet support it.
831 * Reads the time from the battery backed persistent clock.
832 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
834 * XXX - Do be sure to remove it once all arches implement it.
836 void __weak read_persistent_clock(struct timespec *ts)
843 * read_boot_clock - Return time of the system start.
845 * Weak dummy function for arches that do not yet support it.
846 * Function to read the exact time the system has been started.
847 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
849 * XXX - Do be sure to remove it once all arches implement it.
851 void __weak read_boot_clock(struct timespec *ts)
858 * timekeeping_init - Initializes the clocksource and common timekeeping values
860 void __init timekeeping_init(void)
862 struct timekeeper *tk = &tk_core.timekeeper;
863 struct clocksource *clock;
865 struct timespec64 now, boot, tmp;
868 read_persistent_clock(&ts);
869 now = timespec_to_timespec64(ts);
870 if (!timespec64_valid_strict(&now)) {
871 pr_warn("WARNING: Persistent clock returned invalid value!\n"
872 " Check your CMOS/BIOS settings.\n");
875 } else if (now.tv_sec || now.tv_nsec)
876 persistent_clock_exist = true;
878 read_boot_clock(&ts);
879 boot = timespec_to_timespec64(ts);
880 if (!timespec64_valid_strict(&boot)) {
881 pr_warn("WARNING: Boot clock returned invalid value!\n"
882 " Check your CMOS/BIOS settings.\n");
887 raw_spin_lock_irqsave(&timekeeper_lock, flags);
888 write_seqcount_begin(&tk_core.seq);
891 clock = clocksource_default_clock();
893 clock->enable(clock);
894 tk_setup_internals(tk, clock);
896 tk_set_xtime(tk, &now);
897 tk->raw_time.tv_sec = 0;
898 tk->raw_time.tv_nsec = 0;
899 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
902 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
903 tk_set_wall_to_mono(tk, tmp);
907 tk_set_sleep_time(tk, tmp);
909 timekeeping_update(tk, TK_MIRROR);
911 write_seqcount_end(&tk_core.seq);
912 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
915 /* time in seconds when suspend began */
916 static struct timespec64 timekeeping_suspend_time;
919 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
920 * @delta: pointer to a timespec delta value
922 * Takes a timespec offset measuring a suspend interval and properly
923 * adds the sleep offset to the timekeeping variables.
925 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
926 struct timespec64 *delta)
928 if (!timespec64_valid_strict(delta)) {
929 printk_deferred(KERN_WARNING
930 "__timekeeping_inject_sleeptime: Invalid "
931 "sleep delta value!\n");
934 tk_xtime_add(tk, delta);
935 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
936 tk_set_sleep_time(tk, timespec64_add(tk->total_sleep_time, *delta));
937 tk_debug_account_sleep_time(delta);
941 * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values
942 * @delta: pointer to a timespec delta value
944 * This hook is for architectures that cannot support read_persistent_clock
945 * because their RTC/persistent clock is only accessible when irqs are enabled.
947 * This function should only be called by rtc_resume(), and allows
948 * a suspend offset to be injected into the timekeeping values.
950 void timekeeping_inject_sleeptime(struct timespec *delta)
952 struct timekeeper *tk = &tk_core.timekeeper;
953 struct timespec64 tmp;
957 * Make sure we don't set the clock twice, as timekeeping_resume()
960 if (has_persistent_clock())
963 raw_spin_lock_irqsave(&timekeeper_lock, flags);
964 write_seqcount_begin(&tk_core.seq);
966 timekeeping_forward_now(tk);
968 tmp = timespec_to_timespec64(*delta);
969 __timekeeping_inject_sleeptime(tk, &tmp);
971 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
973 write_seqcount_end(&tk_core.seq);
974 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
976 /* signal hrtimers about time change */
981 * timekeeping_resume - Resumes the generic timekeeping subsystem.
983 * This is for the generic clocksource timekeeping.
984 * xtime/wall_to_monotonic/jiffies/etc are
985 * still managed by arch specific suspend/resume code.
987 static void timekeeping_resume(void)
989 struct timekeeper *tk = &tk_core.timekeeper;
990 struct clocksource *clock = tk->clock;
992 struct timespec64 ts_new, ts_delta;
994 cycle_t cycle_now, cycle_delta;
995 bool suspendtime_found = false;
997 read_persistent_clock(&tmp);
998 ts_new = timespec_to_timespec64(tmp);
1000 clockevents_resume();
1001 clocksource_resume();
1003 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1004 write_seqcount_begin(&tk_core.seq);
1007 * After system resumes, we need to calculate the suspended time and
1008 * compensate it for the OS time. There are 3 sources that could be
1009 * used: Nonstop clocksource during suspend, persistent clock and rtc
1012 * One specific platform may have 1 or 2 or all of them, and the
1013 * preference will be:
1014 * suspend-nonstop clocksource -> persistent clock -> rtc
1015 * The less preferred source will only be tried if there is no better
1016 * usable source. The rtc part is handled separately in rtc core code.
1018 cycle_now = clock->read(clock);
1019 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1020 cycle_now > clock->cycle_last) {
1021 u64 num, max = ULLONG_MAX;
1022 u32 mult = clock->mult;
1023 u32 shift = clock->shift;
1026 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
1029 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1030 * suspended time is too long. In that case we need do the
1031 * 64 bits math carefully
1034 if (cycle_delta > max) {
1035 num = div64_u64(cycle_delta, max);
1036 nsec = (((u64) max * mult) >> shift) * num;
1037 cycle_delta -= num * max;
1039 nsec += ((u64) cycle_delta * mult) >> shift;
1041 ts_delta = ns_to_timespec64(nsec);
1042 suspendtime_found = true;
1043 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1044 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1045 suspendtime_found = true;
1048 if (suspendtime_found)
1049 __timekeeping_inject_sleeptime(tk, &ts_delta);
1051 /* Re-base the last cycle value */
1052 tk->cycle_last = clock->cycle_last = cycle_now;
1054 timekeeping_suspended = 0;
1055 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1056 write_seqcount_end(&tk_core.seq);
1057 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1059 touch_softlockup_watchdog();
1061 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
1063 /* Resume hrtimers */
1067 static int timekeeping_suspend(void)
1069 struct timekeeper *tk = &tk_core.timekeeper;
1070 unsigned long flags;
1071 struct timespec64 delta, delta_delta;
1072 static struct timespec64 old_delta;
1073 struct timespec tmp;
1075 read_persistent_clock(&tmp);
1076 timekeeping_suspend_time = timespec_to_timespec64(tmp);
1079 * On some systems the persistent_clock can not be detected at
1080 * timekeeping_init by its return value, so if we see a valid
1081 * value returned, update the persistent_clock_exists flag.
1083 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1084 persistent_clock_exist = true;
1086 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1087 write_seqcount_begin(&tk_core.seq);
1088 timekeeping_forward_now(tk);
1089 timekeeping_suspended = 1;
1092 * To avoid drift caused by repeated suspend/resumes,
1093 * which each can add ~1 second drift error,
1094 * try to compensate so the difference in system time
1095 * and persistent_clock time stays close to constant.
1097 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1098 delta_delta = timespec64_sub(delta, old_delta);
1099 if (abs(delta_delta.tv_sec) >= 2) {
1101 * if delta_delta is too large, assume time correction
1102 * has occured and set old_delta to the current delta.
1106 /* Otherwise try to adjust old_system to compensate */
1107 timekeeping_suspend_time =
1108 timespec64_add(timekeeping_suspend_time, delta_delta);
1111 timekeeping_update(tk, TK_MIRROR);
1112 write_seqcount_end(&tk_core.seq);
1113 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1115 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
1116 clocksource_suspend();
1117 clockevents_suspend();
1122 /* sysfs resume/suspend bits for timekeeping */
1123 static struct syscore_ops timekeeping_syscore_ops = {
1124 .resume = timekeeping_resume,
1125 .suspend = timekeeping_suspend,
1128 static int __init timekeeping_init_ops(void)
1130 register_syscore_ops(&timekeeping_syscore_ops);
1134 device_initcall(timekeeping_init_ops);
1137 * If the error is already larger, we look ahead even further
1138 * to compensate for late or lost adjustments.
1140 static __always_inline int timekeeping_bigadjust(struct timekeeper *tk,
1141 s64 error, s64 *interval,
1145 u32 look_ahead, adj;
1149 * Use the current error value to determine how much to look ahead.
1150 * The larger the error the slower we adjust for it to avoid problems
1151 * with losing too many ticks, otherwise we would overadjust and
1152 * produce an even larger error. The smaller the adjustment the
1153 * faster we try to adjust for it, as lost ticks can do less harm
1154 * here. This is tuned so that an error of about 1 msec is adjusted
1155 * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
1157 error2 = tk->ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
1158 error2 = abs(error2);
1159 for (look_ahead = 0; error2 > 0; look_ahead++)
1163 * Now calculate the error in (1 << look_ahead) ticks, but first
1164 * remove the single look ahead already included in the error.
1166 tick_error = ntp_tick_length() >> (tk->ntp_error_shift + 1);
1167 tick_error -= tk->xtime_interval >> 1;
1168 error = ((error - tick_error) >> look_ahead) + tick_error;
1170 /* Finally calculate the adjustment shift value. */
1175 *interval = -*interval;
1179 for (adj = 0; error > i; adj++)
1188 * Adjust the multiplier to reduce the error value,
1189 * this is optimized for the most common adjustments of -1,0,1,
1190 * for other values we can do a bit more work.
1192 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1194 s64 error, interval = tk->cycle_interval;
1198 * The point of this is to check if the error is greater than half
1201 * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs.
1203 * Note we subtract one in the shift, so that error is really error*2.
1204 * This "saves" dividing(shifting) interval twice, but keeps the
1205 * (error > interval) comparison as still measuring if error is
1206 * larger than half an interval.
1208 * Note: It does not "save" on aggravation when reading the code.
1210 error = tk->ntp_error >> (tk->ntp_error_shift - 1);
1211 if (error > interval) {
1213 * We now divide error by 4(via shift), which checks if
1214 * the error is greater than twice the interval.
1215 * If it is greater, we need a bigadjust, if its smaller,
1216 * we can adjust by 1.
1219 if (likely(error <= interval))
1222 adj = timekeeping_bigadjust(tk, error, &interval, &offset);
1224 if (error < -interval) {
1225 /* See comment above, this is just switched for the negative */
1227 if (likely(error >= -interval)) {
1229 interval = -interval;
1232 adj = timekeeping_bigadjust(tk, error, &interval, &offset);
1239 if (unlikely(tk->clock->maxadj &&
1240 (tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) {
1241 printk_deferred_once(KERN_WARNING
1242 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1243 tk->clock->name, (long)tk->mult + adj,
1244 (long)tk->clock->mult + tk->clock->maxadj);
1247 * So the following can be confusing.
1249 * To keep things simple, lets assume adj == 1 for now.
1251 * When adj != 1, remember that the interval and offset values
1252 * have been appropriately scaled so the math is the same.
1254 * The basic idea here is that we're increasing the multiplier
1255 * by one, this causes the xtime_interval to be incremented by
1256 * one cycle_interval. This is because:
1257 * xtime_interval = cycle_interval * mult
1258 * So if mult is being incremented by one:
1259 * xtime_interval = cycle_interval * (mult + 1)
1261 * xtime_interval = (cycle_interval * mult) + cycle_interval
1262 * Which can be shortened to:
1263 * xtime_interval += cycle_interval
1265 * So offset stores the non-accumulated cycles. Thus the current
1266 * time (in shifted nanoseconds) is:
1267 * now = (offset * adj) + xtime_nsec
1268 * Now, even though we're adjusting the clock frequency, we have
1269 * to keep time consistent. In other words, we can't jump back
1270 * in time, and we also want to avoid jumping forward in time.
1272 * So given the same offset value, we need the time to be the same
1273 * both before and after the freq adjustment.
1274 * now = (offset * adj_1) + xtime_nsec_1
1275 * now = (offset * adj_2) + xtime_nsec_2
1277 * (offset * adj_1) + xtime_nsec_1 =
1278 * (offset * adj_2) + xtime_nsec_2
1282 * (offset * adj_1) + xtime_nsec_1 =
1283 * (offset * (adj_1+1)) + xtime_nsec_2
1284 * (offset * adj_1) + xtime_nsec_1 =
1285 * (offset * adj_1) + offset + xtime_nsec_2
1286 * Canceling the sides:
1287 * xtime_nsec_1 = offset + xtime_nsec_2
1289 * xtime_nsec_2 = xtime_nsec_1 - offset
1290 * Which simplfies to:
1291 * xtime_nsec -= offset
1293 * XXX - TODO: Doc ntp_error calculation.
1296 tk->xtime_interval += interval;
1297 tk->xtime_nsec -= offset;
1298 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1302 * It may be possible that when we entered this function, xtime_nsec
1303 * was very small. Further, if we're slightly speeding the clocksource
1304 * in the code above, its possible the required corrective factor to
1305 * xtime_nsec could cause it to underflow.
1307 * Now, since we already accumulated the second, cannot simply roll
1308 * the accumulated second back, since the NTP subsystem has been
1309 * notified via second_overflow. So instead we push xtime_nsec forward
1310 * by the amount we underflowed, and add that amount into the error.
1312 * We'll correct this error next time through this function, when
1313 * xtime_nsec is not as small.
1315 if (unlikely((s64)tk->xtime_nsec < 0)) {
1316 s64 neg = -(s64)tk->xtime_nsec;
1318 tk->ntp_error += neg << tk->ntp_error_shift;
1324 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1326 * Helper function that accumulates a the nsecs greater then a second
1327 * from the xtime_nsec field to the xtime_secs field.
1328 * It also calls into the NTP code to handle leapsecond processing.
1331 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1333 u64 nsecps = (u64)NSEC_PER_SEC << tk->shift;
1334 unsigned int clock_set = 0;
1336 while (tk->xtime_nsec >= nsecps) {
1339 tk->xtime_nsec -= nsecps;
1342 /* Figure out if its a leap sec and apply if needed */
1343 leap = second_overflow(tk->xtime_sec);
1344 if (unlikely(leap)) {
1345 struct timespec64 ts;
1347 tk->xtime_sec += leap;
1351 tk_set_wall_to_mono(tk,
1352 timespec64_sub(tk->wall_to_monotonic, ts));
1354 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1356 clock_set = TK_CLOCK_WAS_SET;
1363 * logarithmic_accumulation - shifted accumulation of cycles
1365 * This functions accumulates a shifted interval of cycles into
1366 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1369 * Returns the unconsumed cycles.
1371 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
1373 unsigned int *clock_set)
1375 cycle_t interval = tk->cycle_interval << shift;
1378 /* If the offset is smaller then a shifted interval, do nothing */
1379 if (offset < interval)
1382 /* Accumulate one shifted interval */
1384 tk->cycle_last += interval;
1386 tk->xtime_nsec += tk->xtime_interval << shift;
1387 *clock_set |= accumulate_nsecs_to_secs(tk);
1389 /* Accumulate raw time */
1390 raw_nsecs = (u64)tk->raw_interval << shift;
1391 raw_nsecs += tk->raw_time.tv_nsec;
1392 if (raw_nsecs >= NSEC_PER_SEC) {
1393 u64 raw_secs = raw_nsecs;
1394 raw_nsecs = do_div(raw_secs, NSEC_PER_SEC);
1395 tk->raw_time.tv_sec += raw_secs;
1397 tk->raw_time.tv_nsec = raw_nsecs;
1399 /* Accumulate error between NTP and clock interval */
1400 tk->ntp_error += ntp_tick_length() << shift;
1401 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
1402 (tk->ntp_error_shift + shift);
1408 * update_wall_time - Uses the current clocksource to increment the wall time
1411 void update_wall_time(void)
1413 struct clocksource *clock;
1414 struct timekeeper *real_tk = &tk_core.timekeeper;
1415 struct timekeeper *tk = &shadow_timekeeper;
1417 int shift = 0, maxshift;
1418 unsigned int clock_set = 0;
1419 unsigned long flags;
1421 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1423 /* Make sure we're fully resumed: */
1424 if (unlikely(timekeeping_suspended))
1427 clock = real_tk->clock;
1429 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1430 offset = real_tk->cycle_interval;
1432 offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
1435 /* Check if there's really nothing to do */
1436 if (offset < real_tk->cycle_interval)
1440 * With NO_HZ we may have to accumulate many cycle_intervals
1441 * (think "ticks") worth of time at once. To do this efficiently,
1442 * we calculate the largest doubling multiple of cycle_intervals
1443 * that is smaller than the offset. We then accumulate that
1444 * chunk in one go, and then try to consume the next smaller
1447 shift = ilog2(offset) - ilog2(tk->cycle_interval);
1448 shift = max(0, shift);
1449 /* Bound shift to one less than what overflows tick_length */
1450 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
1451 shift = min(shift, maxshift);
1452 while (offset >= tk->cycle_interval) {
1453 offset = logarithmic_accumulation(tk, offset, shift,
1455 if (offset < tk->cycle_interval<<shift)
1459 /* correct the clock when NTP error is too big */
1460 timekeeping_adjust(tk, offset);
1463 * XXX This can be killed once everyone converts
1464 * to the new update_vsyscall.
1466 old_vsyscall_fixup(tk);
1469 * Finally, make sure that after the rounding
1470 * xtime_nsec isn't larger than NSEC_PER_SEC
1472 clock_set |= accumulate_nsecs_to_secs(tk);
1474 write_seqcount_begin(&tk_core.seq);
1475 /* Update clock->cycle_last with the new value */
1476 clock->cycle_last = tk->cycle_last;
1478 * Update the real timekeeper.
1480 * We could avoid this memcpy by switching pointers, but that
1481 * requires changes to all other timekeeper usage sites as
1482 * well, i.e. move the timekeeper pointer getter into the
1483 * spinlocked/seqcount protected sections. And we trade this
1484 * memcpy under the tk_core.seq against one before we start
1487 memcpy(real_tk, tk, sizeof(*tk));
1488 timekeeping_update(real_tk, clock_set);
1489 write_seqcount_end(&tk_core.seq);
1491 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1493 /* Have to call _delayed version, since in irq context*/
1494 clock_was_set_delayed();
1498 * getboottime - Return the real time of system boot.
1499 * @ts: pointer to the timespec to be set
1501 * Returns the wall-time of boot in a timespec.
1503 * This is based on the wall_to_monotonic offset and the total suspend
1504 * time. Calls to settimeofday will affect the value returned (which
1505 * basically means that however wrong your real time clock is at boot time,
1506 * you get the right time here).
1508 void getboottime(struct timespec *ts)
1510 struct timekeeper *tk = &tk_core.timekeeper;
1511 struct timespec boottime = {
1512 .tv_sec = tk->wall_to_monotonic.tv_sec +
1513 tk->total_sleep_time.tv_sec,
1514 .tv_nsec = tk->wall_to_monotonic.tv_nsec +
1515 tk->total_sleep_time.tv_nsec
1518 set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec);
1520 EXPORT_SYMBOL_GPL(getboottime);
1523 * get_monotonic_boottime - Returns monotonic time since boot
1524 * @ts: pointer to the timespec to be set
1526 * Returns the monotonic time since boot in a timespec.
1528 * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also
1529 * includes the time spent in suspend.
1531 void get_monotonic_boottime(struct timespec *ts)
1533 struct timekeeper *tk = &tk_core.timekeeper;
1534 struct timespec64 tomono, sleep, ret;
1538 WARN_ON(timekeeping_suspended);
1541 seq = read_seqcount_begin(&tk_core.seq);
1542 ret.tv_sec = tk->xtime_sec;
1543 nsec = timekeeping_get_ns(tk);
1544 tomono = tk->wall_to_monotonic;
1545 sleep = tk->total_sleep_time;
1547 } while (read_seqcount_retry(&tk_core.seq, seq));
1549 ret.tv_sec += tomono.tv_sec + sleep.tv_sec;
1551 timespec64_add_ns(&ret, nsec + tomono.tv_nsec + sleep.tv_nsec);
1552 *ts = timespec64_to_timespec(ret);
1554 EXPORT_SYMBOL_GPL(get_monotonic_boottime);
1557 * ktime_get_boottime - Returns monotonic time since boot in a ktime
1559 * Returns the monotonic time since boot in a ktime
1561 * This is similar to CLOCK_MONTONIC/ktime_get, but also
1562 * includes the time spent in suspend.
1564 ktime_t ktime_get_boottime(void)
1568 get_monotonic_boottime(&ts);
1569 return timespec_to_ktime(ts);
1571 EXPORT_SYMBOL_GPL(ktime_get_boottime);
1574 * monotonic_to_bootbased - Convert the monotonic time to boot based.
1575 * @ts: pointer to the timespec to be converted
1577 void monotonic_to_bootbased(struct timespec *ts)
1579 struct timekeeper *tk = &tk_core.timekeeper;
1580 struct timespec64 ts64;
1582 ts64 = timespec_to_timespec64(*ts);
1583 ts64 = timespec64_add(ts64, tk->total_sleep_time);
1584 *ts = timespec64_to_timespec(ts64);
1586 EXPORT_SYMBOL_GPL(monotonic_to_bootbased);
1588 unsigned long get_seconds(void)
1590 struct timekeeper *tk = &tk_core.timekeeper;
1592 return tk->xtime_sec;
1594 EXPORT_SYMBOL(get_seconds);
1596 struct timespec __current_kernel_time(void)
1598 struct timekeeper *tk = &tk_core.timekeeper;
1600 return timespec64_to_timespec(tk_xtime(tk));
1603 struct timespec current_kernel_time(void)
1605 struct timekeeper *tk = &tk_core.timekeeper;
1606 struct timespec64 now;
1610 seq = read_seqcount_begin(&tk_core.seq);
1613 } while (read_seqcount_retry(&tk_core.seq, seq));
1615 return timespec64_to_timespec(now);
1617 EXPORT_SYMBOL(current_kernel_time);
1619 struct timespec get_monotonic_coarse(void)
1621 struct timekeeper *tk = &tk_core.timekeeper;
1622 struct timespec64 now, mono;
1626 seq = read_seqcount_begin(&tk_core.seq);
1629 mono = tk->wall_to_monotonic;
1630 } while (read_seqcount_retry(&tk_core.seq, seq));
1632 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
1633 now.tv_nsec + mono.tv_nsec);
1635 return timespec64_to_timespec(now);
1639 * Must hold jiffies_lock
1641 void do_timer(unsigned long ticks)
1643 jiffies_64 += ticks;
1644 calc_global_load(ticks);
1648 * ktime_get_update_offsets_tick - hrtimer helper
1649 * @offs_real: pointer to storage for monotonic -> realtime offset
1650 * @offs_boot: pointer to storage for monotonic -> boottime offset
1651 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1653 * Returns monotonic time at last tick and various offsets
1655 ktime_t ktime_get_update_offsets_tick(ktime_t *offs_real, ktime_t *offs_boot,
1658 struct timekeeper *tk = &tk_core.timekeeper;
1659 struct timespec64 ts;
1664 seq = read_seqcount_begin(&tk_core.seq);
1667 *offs_real = tk->offs_real;
1668 *offs_boot = tk->offs_boot;
1669 *offs_tai = tk->offs_tai;
1670 } while (read_seqcount_retry(&tk_core.seq, seq));
1672 now = ktime_set(ts.tv_sec, ts.tv_nsec);
1673 now = ktime_sub(now, *offs_real);
1677 #ifdef CONFIG_HIGH_RES_TIMERS
1679 * ktime_get_update_offsets_now - hrtimer helper
1680 * @offs_real: pointer to storage for monotonic -> realtime offset
1681 * @offs_boot: pointer to storage for monotonic -> boottime offset
1682 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1684 * Returns current monotonic time and updates the offsets
1685 * Called from hrtimer_interrupt() or retrigger_next_event()
1687 ktime_t ktime_get_update_offsets_now(ktime_t *offs_real, ktime_t *offs_boot,
1690 struct timekeeper *tk = &tk_core.timekeeper;
1696 seq = read_seqcount_begin(&tk_core.seq);
1698 secs = tk->xtime_sec;
1699 nsecs = timekeeping_get_ns(tk);
1701 *offs_real = tk->offs_real;
1702 *offs_boot = tk->offs_boot;
1703 *offs_tai = tk->offs_tai;
1704 } while (read_seqcount_retry(&tk_core.seq, seq));
1706 now = ktime_add_ns(ktime_set(secs, 0), nsecs);
1707 now = ktime_sub(now, *offs_real);
1713 * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format
1715 ktime_t ktime_get_monotonic_offset(void)
1717 struct timekeeper *tk = &tk_core.timekeeper;
1719 struct timespec64 wtom;
1722 seq = read_seqcount_begin(&tk_core.seq);
1723 wtom = tk->wall_to_monotonic;
1724 } while (read_seqcount_retry(&tk_core.seq, seq));
1726 return timespec64_to_ktime(wtom);
1728 EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset);
1731 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1733 int do_adjtimex(struct timex *txc)
1735 struct timekeeper *tk = &tk_core.timekeeper;
1736 unsigned long flags;
1737 struct timespec64 ts;
1741 /* Validate the data before disabling interrupts */
1742 ret = ntp_validate_timex(txc);
1746 if (txc->modes & ADJ_SETOFFSET) {
1747 struct timespec delta;
1748 delta.tv_sec = txc->time.tv_sec;
1749 delta.tv_nsec = txc->time.tv_usec;
1750 if (!(txc->modes & ADJ_NANO))
1751 delta.tv_nsec *= 1000;
1752 ret = timekeeping_inject_offset(&delta);
1757 getnstimeofday64(&ts);
1759 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1760 write_seqcount_begin(&tk_core.seq);
1762 orig_tai = tai = tk->tai_offset;
1763 ret = __do_adjtimex(txc, &ts, &tai);
1765 if (tai != orig_tai) {
1766 __timekeeping_set_tai_offset(tk, tai);
1767 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1769 write_seqcount_end(&tk_core.seq);
1770 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1772 if (tai != orig_tai)
1775 ntp_notify_cmos_timer();
1780 #ifdef CONFIG_NTP_PPS
1782 * hardpps() - Accessor function to NTP __hardpps function
1784 void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
1786 unsigned long flags;
1788 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1789 write_seqcount_begin(&tk_core.seq);
1791 __hardpps(phase_ts, raw_ts);
1793 write_seqcount_end(&tk_core.seq);
1794 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1796 EXPORT_SYMBOL(hardpps);
1800 * xtime_update() - advances the timekeeping infrastructure
1801 * @ticks: number of ticks, that have elapsed since the last call.
1803 * Must be called with interrupts disabled.
1805 void xtime_update(unsigned long ticks)
1807 write_seqlock(&jiffies_lock);
1809 write_sequnlock(&jiffies_lock);