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 inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
102 tk->offs_boot = ktime_add(tk->offs_boot, delta);
106 * tk_setup_internals - Set up internals to use clocksource clock.
108 * @tk: The target timekeeper to setup.
109 * @clock: Pointer to clocksource.
111 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
112 * pair and interval request.
114 * Unless you're the timekeeping code, you should not be using this!
116 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
119 u64 tmp, ntpinterval;
120 struct clocksource *old_clock;
122 old_clock = tk->clock;
124 tk->cycle_last = clock->cycle_last = clock->read(clock);
126 /* Do the ns -> cycle conversion first, using original mult */
127 tmp = NTP_INTERVAL_LENGTH;
128 tmp <<= clock->shift;
130 tmp += clock->mult/2;
131 do_div(tmp, clock->mult);
135 interval = (cycle_t) tmp;
136 tk->cycle_interval = interval;
138 /* Go back from cycles -> shifted ns */
139 tk->xtime_interval = (u64) interval * clock->mult;
140 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
142 ((u64) interval * clock->mult) >> clock->shift;
144 /* if changing clocks, convert xtime_nsec shift units */
146 int shift_change = clock->shift - old_clock->shift;
147 if (shift_change < 0)
148 tk->xtime_nsec >>= -shift_change;
150 tk->xtime_nsec <<= shift_change;
152 tk->shift = clock->shift;
155 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
158 * The timekeeper keeps its own mult values for the currently
159 * active clocksource. These value will be adjusted via NTP
160 * to counteract clock drifting.
162 tk->mult = clock->mult;
165 /* Timekeeper helper functions. */
167 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
168 static u32 default_arch_gettimeoffset(void) { return 0; }
169 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
171 static inline u32 arch_gettimeoffset(void) { return 0; }
174 static inline s64 timekeeping_get_ns(struct timekeeper *tk)
176 cycle_t cycle_now, delta;
177 struct clocksource *clock;
180 /* read clocksource: */
182 cycle_now = clock->read(clock);
184 /* calculate the delta since the last update_wall_time: */
185 delta = clocksource_delta(cycle_now, clock->cycle_last, clock->mask);
187 nsec = delta * tk->mult + tk->xtime_nsec;
190 /* If arch requires, add in get_arch_timeoffset() */
191 return nsec + arch_gettimeoffset();
194 static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)
196 cycle_t cycle_now, delta;
197 struct clocksource *clock;
200 /* read clocksource: */
202 cycle_now = clock->read(clock);
204 /* calculate the delta since the last update_wall_time: */
205 delta = clocksource_delta(cycle_now, clock->cycle_last, clock->mask);
207 /* convert delta to nanoseconds. */
208 nsec = clocksource_cyc2ns(delta, clock->mult, clock->shift);
210 /* If arch requires, add in get_arch_timeoffset() */
211 return nsec + arch_gettimeoffset();
214 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
216 static inline void update_vsyscall(struct timekeeper *tk)
221 update_vsyscall_old(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult);
224 static inline void old_vsyscall_fixup(struct timekeeper *tk)
229 * Store only full nanoseconds into xtime_nsec after rounding
230 * it up and add the remainder to the error difference.
231 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
232 * by truncating the remainder in vsyscalls. However, it causes
233 * additional work to be done in timekeeping_adjust(). Once
234 * the vsyscall implementations are converted to use xtime_nsec
235 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
236 * users are removed, this can be killed.
238 remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1);
239 tk->xtime_nsec -= remainder;
240 tk->xtime_nsec += 1ULL << tk->shift;
241 tk->ntp_error += remainder << tk->ntp_error_shift;
242 tk->ntp_error -= (1ULL << tk->shift) << tk->ntp_error_shift;
245 #define old_vsyscall_fixup(tk)
248 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
250 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
252 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
256 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
258 int pvclock_gtod_register_notifier(struct notifier_block *nb)
260 struct timekeeper *tk = &tk_core.timekeeper;
264 raw_spin_lock_irqsave(&timekeeper_lock, flags);
265 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
266 update_pvclock_gtod(tk, true);
267 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
271 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
274 * pvclock_gtod_unregister_notifier - unregister a pvclock
275 * timedata update listener
277 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
282 raw_spin_lock_irqsave(&timekeeper_lock, flags);
283 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
284 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
288 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
291 * Update the ktime_t based scalar nsec members of the timekeeper
293 static inline void tk_update_ktime_data(struct timekeeper *tk)
298 * The xtime based monotonic readout is:
299 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
300 * The ktime based monotonic readout is:
301 * nsec = base_mono + now();
302 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
304 nsec = (s64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
305 nsec *= NSEC_PER_SEC;
306 nsec += tk->wall_to_monotonic.tv_nsec;
307 tk->base_mono = ns_to_ktime(nsec);
309 /* Update the monotonic raw base */
310 tk->base_raw = timespec64_to_ktime(tk->raw_time);
313 /* must hold timekeeper_lock */
314 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
316 if (action & TK_CLEAR_NTP) {
321 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
323 tk_update_ktime_data(tk);
325 if (action & TK_MIRROR)
326 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
327 sizeof(tk_core.timekeeper));
331 * timekeeping_forward_now - update clock to the current time
333 * Forward the current clock to update its state since the last call to
334 * update_wall_time(). This is useful before significant clock changes,
335 * as it avoids having to deal with this time offset explicitly.
337 static void timekeeping_forward_now(struct timekeeper *tk)
339 cycle_t cycle_now, delta;
340 struct clocksource *clock;
344 cycle_now = clock->read(clock);
345 delta = clocksource_delta(cycle_now, clock->cycle_last, clock->mask);
346 tk->cycle_last = clock->cycle_last = cycle_now;
348 tk->xtime_nsec += delta * tk->mult;
350 /* If arch requires, add in get_arch_timeoffset() */
351 tk->xtime_nsec += (u64)arch_gettimeoffset() << tk->shift;
353 tk_normalize_xtime(tk);
355 nsec = clocksource_cyc2ns(delta, clock->mult, clock->shift);
356 timespec64_add_ns(&tk->raw_time, nsec);
360 * __getnstimeofday64 - Returns the time of day in a timespec64.
361 * @ts: pointer to the timespec to be set
363 * Updates the time of day in the timespec.
364 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
366 int __getnstimeofday64(struct timespec64 *ts)
368 struct timekeeper *tk = &tk_core.timekeeper;
373 seq = read_seqcount_begin(&tk_core.seq);
375 ts->tv_sec = tk->xtime_sec;
376 nsecs = timekeeping_get_ns(tk);
378 } while (read_seqcount_retry(&tk_core.seq, seq));
381 timespec64_add_ns(ts, nsecs);
384 * Do not bail out early, in case there were callers still using
385 * the value, even in the face of the WARN_ON.
387 if (unlikely(timekeeping_suspended))
391 EXPORT_SYMBOL(__getnstimeofday64);
394 * getnstimeofday64 - Returns the time of day in a timespec64.
395 * @ts: pointer to the timespec to be set
397 * Returns the time of day in a timespec (WARN if suspended).
399 void getnstimeofday64(struct timespec64 *ts)
401 WARN_ON(__getnstimeofday64(ts));
403 EXPORT_SYMBOL(getnstimeofday64);
405 ktime_t ktime_get(void)
407 struct timekeeper *tk = &tk_core.timekeeper;
412 WARN_ON(timekeeping_suspended);
415 seq = read_seqcount_begin(&tk_core.seq);
416 base = tk->base_mono;
417 nsecs = timekeeping_get_ns(tk);
419 } while (read_seqcount_retry(&tk_core.seq, seq));
421 return ktime_add_ns(base, nsecs);
423 EXPORT_SYMBOL_GPL(ktime_get);
425 static ktime_t *offsets[TK_OFFS_MAX] = {
426 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
427 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
428 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
431 ktime_t ktime_get_with_offset(enum tk_offsets offs)
433 struct timekeeper *tk = &tk_core.timekeeper;
435 ktime_t base, *offset = offsets[offs];
438 WARN_ON(timekeeping_suspended);
441 seq = read_seqcount_begin(&tk_core.seq);
442 base = ktime_add(tk->base_mono, *offset);
443 nsecs = timekeeping_get_ns(tk);
445 } while (read_seqcount_retry(&tk_core.seq, seq));
447 return ktime_add_ns(base, nsecs);
450 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
453 * ktime_mono_to_any() - convert mononotic time to any other time
454 * @tmono: time to convert.
455 * @offs: which offset to use
457 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
459 ktime_t *offset = offsets[offs];
464 seq = read_seqcount_begin(&tk_core.seq);
465 tconv = ktime_add(tmono, *offset);
466 } while (read_seqcount_retry(&tk_core.seq, seq));
470 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
473 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
475 ktime_t ktime_get_raw(void)
477 struct timekeeper *tk = &tk_core.timekeeper;
483 seq = read_seqcount_begin(&tk_core.seq);
485 nsecs = timekeeping_get_ns_raw(tk);
487 } while (read_seqcount_retry(&tk_core.seq, seq));
489 return ktime_add_ns(base, nsecs);
491 EXPORT_SYMBOL_GPL(ktime_get_raw);
494 * ktime_get_ts64 - get the monotonic clock in timespec64 format
495 * @ts: pointer to timespec variable
497 * The function calculates the monotonic clock from the realtime
498 * clock and the wall_to_monotonic offset and stores the result
499 * in normalized timespec format in the variable pointed to by @ts.
501 void ktime_get_ts64(struct timespec64 *ts)
503 struct timekeeper *tk = &tk_core.timekeeper;
504 struct timespec64 tomono;
508 WARN_ON(timekeeping_suspended);
511 seq = read_seqcount_begin(&tk_core.seq);
512 ts->tv_sec = tk->xtime_sec;
513 nsec = timekeeping_get_ns(tk);
514 tomono = tk->wall_to_monotonic;
516 } while (read_seqcount_retry(&tk_core.seq, seq));
518 ts->tv_sec += tomono.tv_sec;
520 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
522 EXPORT_SYMBOL_GPL(ktime_get_ts64);
524 #ifdef CONFIG_NTP_PPS
527 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
528 * @ts_raw: pointer to the timespec to be set to raw monotonic time
529 * @ts_real: pointer to the timespec to be set to the time of day
531 * This function reads both the time of day and raw monotonic time at the
532 * same time atomically and stores the resulting timestamps in timespec
535 void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
537 struct timekeeper *tk = &tk_core.timekeeper;
539 s64 nsecs_raw, nsecs_real;
541 WARN_ON_ONCE(timekeeping_suspended);
544 seq = read_seqcount_begin(&tk_core.seq);
546 *ts_raw = timespec64_to_timespec(tk->raw_time);
547 ts_real->tv_sec = tk->xtime_sec;
548 ts_real->tv_nsec = 0;
550 nsecs_raw = timekeeping_get_ns_raw(tk);
551 nsecs_real = timekeeping_get_ns(tk);
553 } while (read_seqcount_retry(&tk_core.seq, seq));
555 timespec_add_ns(ts_raw, nsecs_raw);
556 timespec_add_ns(ts_real, nsecs_real);
558 EXPORT_SYMBOL(getnstime_raw_and_real);
560 #endif /* CONFIG_NTP_PPS */
563 * do_gettimeofday - Returns the time of day in a timeval
564 * @tv: pointer to the timeval to be set
566 * NOTE: Users should be converted to using getnstimeofday()
568 void do_gettimeofday(struct timeval *tv)
570 struct timespec64 now;
572 getnstimeofday64(&now);
573 tv->tv_sec = now.tv_sec;
574 tv->tv_usec = now.tv_nsec/1000;
576 EXPORT_SYMBOL(do_gettimeofday);
579 * do_settimeofday - Sets the time of day
580 * @tv: pointer to the timespec variable containing the new time
582 * Sets the time of day to the new time and update NTP and notify hrtimers
584 int do_settimeofday(const struct timespec *tv)
586 struct timekeeper *tk = &tk_core.timekeeper;
587 struct timespec64 ts_delta, xt, tmp;
590 if (!timespec_valid_strict(tv))
593 raw_spin_lock_irqsave(&timekeeper_lock, flags);
594 write_seqcount_begin(&tk_core.seq);
596 timekeeping_forward_now(tk);
599 ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;
600 ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec;
602 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
604 tmp = timespec_to_timespec64(*tv);
605 tk_set_xtime(tk, &tmp);
607 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
609 write_seqcount_end(&tk_core.seq);
610 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
612 /* signal hrtimers about time change */
617 EXPORT_SYMBOL(do_settimeofday);
620 * timekeeping_inject_offset - Adds or subtracts from the current time.
621 * @tv: pointer to the timespec variable containing the offset
623 * Adds or subtracts an offset value from the current time.
625 int timekeeping_inject_offset(struct timespec *ts)
627 struct timekeeper *tk = &tk_core.timekeeper;
629 struct timespec64 ts64, tmp;
632 if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
635 ts64 = timespec_to_timespec64(*ts);
637 raw_spin_lock_irqsave(&timekeeper_lock, flags);
638 write_seqcount_begin(&tk_core.seq);
640 timekeeping_forward_now(tk);
642 /* Make sure the proposed value is valid */
643 tmp = timespec64_add(tk_xtime(tk), ts64);
644 if (!timespec64_valid_strict(&tmp)) {
649 tk_xtime_add(tk, &ts64);
650 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
652 error: /* even if we error out, we forwarded the time, so call update */
653 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
655 write_seqcount_end(&tk_core.seq);
656 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
658 /* signal hrtimers about time change */
663 EXPORT_SYMBOL(timekeeping_inject_offset);
667 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
670 s32 timekeeping_get_tai_offset(void)
672 struct timekeeper *tk = &tk_core.timekeeper;
677 seq = read_seqcount_begin(&tk_core.seq);
678 ret = tk->tai_offset;
679 } while (read_seqcount_retry(&tk_core.seq, seq));
685 * __timekeeping_set_tai_offset - Lock free worker function
688 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
690 tk->tai_offset = tai_offset;
691 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
695 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
698 void timekeeping_set_tai_offset(s32 tai_offset)
700 struct timekeeper *tk = &tk_core.timekeeper;
703 raw_spin_lock_irqsave(&timekeeper_lock, flags);
704 write_seqcount_begin(&tk_core.seq);
705 __timekeeping_set_tai_offset(tk, tai_offset);
706 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
707 write_seqcount_end(&tk_core.seq);
708 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
713 * change_clocksource - Swaps clocksources if a new one is available
715 * Accumulates current time interval and initializes new clocksource
717 static int change_clocksource(void *data)
719 struct timekeeper *tk = &tk_core.timekeeper;
720 struct clocksource *new, *old;
723 new = (struct clocksource *) data;
725 raw_spin_lock_irqsave(&timekeeper_lock, flags);
726 write_seqcount_begin(&tk_core.seq);
728 timekeeping_forward_now(tk);
730 * If the cs is in module, get a module reference. Succeeds
731 * for built-in code (owner == NULL) as well.
733 if (try_module_get(new->owner)) {
734 if (!new->enable || new->enable(new) == 0) {
736 tk_setup_internals(tk, new);
739 module_put(old->owner);
741 module_put(new->owner);
744 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
746 write_seqcount_end(&tk_core.seq);
747 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
753 * timekeeping_notify - Install a new clock source
754 * @clock: pointer to the clock source
756 * This function is called from clocksource.c after a new, better clock
757 * source has been registered. The caller holds the clocksource_mutex.
759 int timekeeping_notify(struct clocksource *clock)
761 struct timekeeper *tk = &tk_core.timekeeper;
763 if (tk->clock == clock)
765 stop_machine(change_clocksource, clock, NULL);
767 return tk->clock == clock ? 0 : -1;
771 * getrawmonotonic - Returns the raw monotonic time in a timespec
772 * @ts: pointer to the timespec to be set
774 * Returns the raw monotonic time (completely un-modified by ntp)
776 void getrawmonotonic(struct timespec *ts)
778 struct timekeeper *tk = &tk_core.timekeeper;
779 struct timespec64 ts64;
784 seq = read_seqcount_begin(&tk_core.seq);
785 nsecs = timekeeping_get_ns_raw(tk);
788 } while (read_seqcount_retry(&tk_core.seq, seq));
790 timespec64_add_ns(&ts64, nsecs);
791 *ts = timespec64_to_timespec(ts64);
793 EXPORT_SYMBOL(getrawmonotonic);
796 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
798 int timekeeping_valid_for_hres(void)
800 struct timekeeper *tk = &tk_core.timekeeper;
805 seq = read_seqcount_begin(&tk_core.seq);
807 ret = tk->clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
809 } while (read_seqcount_retry(&tk_core.seq, seq));
815 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
817 u64 timekeeping_max_deferment(void)
819 struct timekeeper *tk = &tk_core.timekeeper;
824 seq = read_seqcount_begin(&tk_core.seq);
826 ret = tk->clock->max_idle_ns;
828 } while (read_seqcount_retry(&tk_core.seq, seq));
834 * read_persistent_clock - Return time from the persistent clock.
836 * Weak dummy function for arches that do not yet support it.
837 * Reads the time from the battery backed persistent clock.
838 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
840 * XXX - Do be sure to remove it once all arches implement it.
842 void __weak read_persistent_clock(struct timespec *ts)
849 * read_boot_clock - Return time of the system start.
851 * Weak dummy function for arches that do not yet support it.
852 * Function to read the exact time the system has been started.
853 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
855 * XXX - Do be sure to remove it once all arches implement it.
857 void __weak read_boot_clock(struct timespec *ts)
864 * timekeeping_init - Initializes the clocksource and common timekeeping values
866 void __init timekeeping_init(void)
868 struct timekeeper *tk = &tk_core.timekeeper;
869 struct clocksource *clock;
871 struct timespec64 now, boot, tmp;
874 read_persistent_clock(&ts);
875 now = timespec_to_timespec64(ts);
876 if (!timespec64_valid_strict(&now)) {
877 pr_warn("WARNING: Persistent clock returned invalid value!\n"
878 " Check your CMOS/BIOS settings.\n");
881 } else if (now.tv_sec || now.tv_nsec)
882 persistent_clock_exist = true;
884 read_boot_clock(&ts);
885 boot = timespec_to_timespec64(ts);
886 if (!timespec64_valid_strict(&boot)) {
887 pr_warn("WARNING: Boot clock returned invalid value!\n"
888 " Check your CMOS/BIOS settings.\n");
893 raw_spin_lock_irqsave(&timekeeper_lock, flags);
894 write_seqcount_begin(&tk_core.seq);
897 clock = clocksource_default_clock();
899 clock->enable(clock);
900 tk_setup_internals(tk, clock);
902 tk_set_xtime(tk, &now);
903 tk->raw_time.tv_sec = 0;
904 tk->raw_time.tv_nsec = 0;
905 tk->base_raw.tv64 = 0;
906 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
909 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
910 tk_set_wall_to_mono(tk, tmp);
912 timekeeping_update(tk, TK_MIRROR);
914 write_seqcount_end(&tk_core.seq);
915 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
918 /* time in seconds when suspend began */
919 static struct timespec64 timekeeping_suspend_time;
922 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
923 * @delta: pointer to a timespec delta value
925 * Takes a timespec offset measuring a suspend interval and properly
926 * adds the sleep offset to the timekeeping variables.
928 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
929 struct timespec64 *delta)
931 if (!timespec64_valid_strict(delta)) {
932 printk_deferred(KERN_WARNING
933 "__timekeeping_inject_sleeptime: Invalid "
934 "sleep delta value!\n");
937 tk_xtime_add(tk, delta);
938 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
939 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
940 tk_debug_account_sleep_time(delta);
944 * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values
945 * @delta: pointer to a timespec delta value
947 * This hook is for architectures that cannot support read_persistent_clock
948 * because their RTC/persistent clock is only accessible when irqs are enabled.
950 * This function should only be called by rtc_resume(), and allows
951 * a suspend offset to be injected into the timekeeping values.
953 void timekeeping_inject_sleeptime(struct timespec *delta)
955 struct timekeeper *tk = &tk_core.timekeeper;
956 struct timespec64 tmp;
960 * Make sure we don't set the clock twice, as timekeeping_resume()
963 if (has_persistent_clock())
966 raw_spin_lock_irqsave(&timekeeper_lock, flags);
967 write_seqcount_begin(&tk_core.seq);
969 timekeeping_forward_now(tk);
971 tmp = timespec_to_timespec64(*delta);
972 __timekeeping_inject_sleeptime(tk, &tmp);
974 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
976 write_seqcount_end(&tk_core.seq);
977 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
979 /* signal hrtimers about time change */
984 * timekeeping_resume - Resumes the generic timekeeping subsystem.
986 * This is for the generic clocksource timekeeping.
987 * xtime/wall_to_monotonic/jiffies/etc are
988 * still managed by arch specific suspend/resume code.
990 static void timekeeping_resume(void)
992 struct timekeeper *tk = &tk_core.timekeeper;
993 struct clocksource *clock = tk->clock;
995 struct timespec64 ts_new, ts_delta;
997 cycle_t cycle_now, cycle_delta;
998 bool suspendtime_found = false;
1000 read_persistent_clock(&tmp);
1001 ts_new = timespec_to_timespec64(tmp);
1003 clockevents_resume();
1004 clocksource_resume();
1006 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1007 write_seqcount_begin(&tk_core.seq);
1010 * After system resumes, we need to calculate the suspended time and
1011 * compensate it for the OS time. There are 3 sources that could be
1012 * used: Nonstop clocksource during suspend, persistent clock and rtc
1015 * One specific platform may have 1 or 2 or all of them, and the
1016 * preference will be:
1017 * suspend-nonstop clocksource -> persistent clock -> rtc
1018 * The less preferred source will only be tried if there is no better
1019 * usable source. The rtc part is handled separately in rtc core code.
1021 cycle_now = clock->read(clock);
1022 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1023 cycle_now > clock->cycle_last) {
1024 u64 num, max = ULLONG_MAX;
1025 u32 mult = clock->mult;
1026 u32 shift = clock->shift;
1029 cycle_delta = clocksource_delta(cycle_now, clock->cycle_last,
1033 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1034 * suspended time is too long. In that case we need do the
1035 * 64 bits math carefully
1038 if (cycle_delta > max) {
1039 num = div64_u64(cycle_delta, max);
1040 nsec = (((u64) max * mult) >> shift) * num;
1041 cycle_delta -= num * max;
1043 nsec += ((u64) cycle_delta * mult) >> shift;
1045 ts_delta = ns_to_timespec64(nsec);
1046 suspendtime_found = true;
1047 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1048 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1049 suspendtime_found = true;
1052 if (suspendtime_found)
1053 __timekeeping_inject_sleeptime(tk, &ts_delta);
1055 /* Re-base the last cycle value */
1056 tk->cycle_last = clock->cycle_last = cycle_now;
1058 timekeeping_suspended = 0;
1059 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1060 write_seqcount_end(&tk_core.seq);
1061 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1063 touch_softlockup_watchdog();
1065 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
1067 /* Resume hrtimers */
1071 static int timekeeping_suspend(void)
1073 struct timekeeper *tk = &tk_core.timekeeper;
1074 unsigned long flags;
1075 struct timespec64 delta, delta_delta;
1076 static struct timespec64 old_delta;
1077 struct timespec tmp;
1079 read_persistent_clock(&tmp);
1080 timekeeping_suspend_time = timespec_to_timespec64(tmp);
1083 * On some systems the persistent_clock can not be detected at
1084 * timekeeping_init by its return value, so if we see a valid
1085 * value returned, update the persistent_clock_exists flag.
1087 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1088 persistent_clock_exist = true;
1090 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1091 write_seqcount_begin(&tk_core.seq);
1092 timekeeping_forward_now(tk);
1093 timekeeping_suspended = 1;
1096 * To avoid drift caused by repeated suspend/resumes,
1097 * which each can add ~1 second drift error,
1098 * try to compensate so the difference in system time
1099 * and persistent_clock time stays close to constant.
1101 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1102 delta_delta = timespec64_sub(delta, old_delta);
1103 if (abs(delta_delta.tv_sec) >= 2) {
1105 * if delta_delta is too large, assume time correction
1106 * has occured and set old_delta to the current delta.
1110 /* Otherwise try to adjust old_system to compensate */
1111 timekeeping_suspend_time =
1112 timespec64_add(timekeeping_suspend_time, delta_delta);
1115 timekeeping_update(tk, TK_MIRROR);
1116 write_seqcount_end(&tk_core.seq);
1117 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1119 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
1120 clocksource_suspend();
1121 clockevents_suspend();
1126 /* sysfs resume/suspend bits for timekeeping */
1127 static struct syscore_ops timekeeping_syscore_ops = {
1128 .resume = timekeeping_resume,
1129 .suspend = timekeeping_suspend,
1132 static int __init timekeeping_init_ops(void)
1134 register_syscore_ops(&timekeeping_syscore_ops);
1138 device_initcall(timekeeping_init_ops);
1141 * If the error is already larger, we look ahead even further
1142 * to compensate for late or lost adjustments.
1144 static __always_inline int timekeeping_bigadjust(struct timekeeper *tk,
1145 s64 error, s64 *interval,
1149 u32 look_ahead, adj;
1153 * Use the current error value to determine how much to look ahead.
1154 * The larger the error the slower we adjust for it to avoid problems
1155 * with losing too many ticks, otherwise we would overadjust and
1156 * produce an even larger error. The smaller the adjustment the
1157 * faster we try to adjust for it, as lost ticks can do less harm
1158 * here. This is tuned so that an error of about 1 msec is adjusted
1159 * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
1161 error2 = tk->ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
1162 error2 = abs(error2);
1163 for (look_ahead = 0; error2 > 0; look_ahead++)
1167 * Now calculate the error in (1 << look_ahead) ticks, but first
1168 * remove the single look ahead already included in the error.
1170 tick_error = ntp_tick_length() >> (tk->ntp_error_shift + 1);
1171 tick_error -= tk->xtime_interval >> 1;
1172 error = ((error - tick_error) >> look_ahead) + tick_error;
1174 /* Finally calculate the adjustment shift value. */
1179 *interval = -*interval;
1183 for (adj = 0; error > i; adj++)
1192 * Adjust the multiplier to reduce the error value,
1193 * this is optimized for the most common adjustments of -1,0,1,
1194 * for other values we can do a bit more work.
1196 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1198 s64 error, interval = tk->cycle_interval;
1202 * The point of this is to check if the error is greater than half
1205 * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs.
1207 * Note we subtract one in the shift, so that error is really error*2.
1208 * This "saves" dividing(shifting) interval twice, but keeps the
1209 * (error > interval) comparison as still measuring if error is
1210 * larger than half an interval.
1212 * Note: It does not "save" on aggravation when reading the code.
1214 error = tk->ntp_error >> (tk->ntp_error_shift - 1);
1215 if (error > interval) {
1217 * We now divide error by 4(via shift), which checks if
1218 * the error is greater than twice the interval.
1219 * If it is greater, we need a bigadjust, if its smaller,
1220 * we can adjust by 1.
1223 if (likely(error <= interval))
1226 adj = timekeeping_bigadjust(tk, error, &interval, &offset);
1228 if (error < -interval) {
1229 /* See comment above, this is just switched for the negative */
1231 if (likely(error >= -interval)) {
1233 interval = -interval;
1236 adj = timekeeping_bigadjust(tk, error, &interval, &offset);
1243 if (unlikely(tk->clock->maxadj &&
1244 (tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) {
1245 printk_deferred_once(KERN_WARNING
1246 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1247 tk->clock->name, (long)tk->mult + adj,
1248 (long)tk->clock->mult + tk->clock->maxadj);
1251 * So the following can be confusing.
1253 * To keep things simple, lets assume adj == 1 for now.
1255 * When adj != 1, remember that the interval and offset values
1256 * have been appropriately scaled so the math is the same.
1258 * The basic idea here is that we're increasing the multiplier
1259 * by one, this causes the xtime_interval to be incremented by
1260 * one cycle_interval. This is because:
1261 * xtime_interval = cycle_interval * mult
1262 * So if mult is being incremented by one:
1263 * xtime_interval = cycle_interval * (mult + 1)
1265 * xtime_interval = (cycle_interval * mult) + cycle_interval
1266 * Which can be shortened to:
1267 * xtime_interval += cycle_interval
1269 * So offset stores the non-accumulated cycles. Thus the current
1270 * time (in shifted nanoseconds) is:
1271 * now = (offset * adj) + xtime_nsec
1272 * Now, even though we're adjusting the clock frequency, we have
1273 * to keep time consistent. In other words, we can't jump back
1274 * in time, and we also want to avoid jumping forward in time.
1276 * So given the same offset value, we need the time to be the same
1277 * both before and after the freq adjustment.
1278 * now = (offset * adj_1) + xtime_nsec_1
1279 * now = (offset * adj_2) + xtime_nsec_2
1281 * (offset * adj_1) + xtime_nsec_1 =
1282 * (offset * adj_2) + xtime_nsec_2
1286 * (offset * adj_1) + xtime_nsec_1 =
1287 * (offset * (adj_1+1)) + xtime_nsec_2
1288 * (offset * adj_1) + xtime_nsec_1 =
1289 * (offset * adj_1) + offset + xtime_nsec_2
1290 * Canceling the sides:
1291 * xtime_nsec_1 = offset + xtime_nsec_2
1293 * xtime_nsec_2 = xtime_nsec_1 - offset
1294 * Which simplfies to:
1295 * xtime_nsec -= offset
1297 * XXX - TODO: Doc ntp_error calculation.
1300 tk->xtime_interval += interval;
1301 tk->xtime_nsec -= offset;
1302 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1306 * It may be possible that when we entered this function, xtime_nsec
1307 * was very small. Further, if we're slightly speeding the clocksource
1308 * in the code above, its possible the required corrective factor to
1309 * xtime_nsec could cause it to underflow.
1311 * Now, since we already accumulated the second, cannot simply roll
1312 * the accumulated second back, since the NTP subsystem has been
1313 * notified via second_overflow. So instead we push xtime_nsec forward
1314 * by the amount we underflowed, and add that amount into the error.
1316 * We'll correct this error next time through this function, when
1317 * xtime_nsec is not as small.
1319 if (unlikely((s64)tk->xtime_nsec < 0)) {
1320 s64 neg = -(s64)tk->xtime_nsec;
1322 tk->ntp_error += neg << tk->ntp_error_shift;
1328 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1330 * Helper function that accumulates a the nsecs greater then a second
1331 * from the xtime_nsec field to the xtime_secs field.
1332 * It also calls into the NTP code to handle leapsecond processing.
1335 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1337 u64 nsecps = (u64)NSEC_PER_SEC << tk->shift;
1338 unsigned int clock_set = 0;
1340 while (tk->xtime_nsec >= nsecps) {
1343 tk->xtime_nsec -= nsecps;
1346 /* Figure out if its a leap sec and apply if needed */
1347 leap = second_overflow(tk->xtime_sec);
1348 if (unlikely(leap)) {
1349 struct timespec64 ts;
1351 tk->xtime_sec += leap;
1355 tk_set_wall_to_mono(tk,
1356 timespec64_sub(tk->wall_to_monotonic, ts));
1358 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1360 clock_set = TK_CLOCK_WAS_SET;
1367 * logarithmic_accumulation - shifted accumulation of cycles
1369 * This functions accumulates a shifted interval of cycles into
1370 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1373 * Returns the unconsumed cycles.
1375 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
1377 unsigned int *clock_set)
1379 cycle_t interval = tk->cycle_interval << shift;
1382 /* If the offset is smaller then a shifted interval, do nothing */
1383 if (offset < interval)
1386 /* Accumulate one shifted interval */
1388 tk->cycle_last += interval;
1390 tk->xtime_nsec += tk->xtime_interval << shift;
1391 *clock_set |= accumulate_nsecs_to_secs(tk);
1393 /* Accumulate raw time */
1394 raw_nsecs = (u64)tk->raw_interval << shift;
1395 raw_nsecs += tk->raw_time.tv_nsec;
1396 if (raw_nsecs >= NSEC_PER_SEC) {
1397 u64 raw_secs = raw_nsecs;
1398 raw_nsecs = do_div(raw_secs, NSEC_PER_SEC);
1399 tk->raw_time.tv_sec += raw_secs;
1401 tk->raw_time.tv_nsec = raw_nsecs;
1403 /* Accumulate error between NTP and clock interval */
1404 tk->ntp_error += ntp_tick_length() << shift;
1405 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
1406 (tk->ntp_error_shift + shift);
1412 * update_wall_time - Uses the current clocksource to increment the wall time
1415 void update_wall_time(void)
1417 struct clocksource *clock;
1418 struct timekeeper *real_tk = &tk_core.timekeeper;
1419 struct timekeeper *tk = &shadow_timekeeper;
1421 int shift = 0, maxshift;
1422 unsigned int clock_set = 0;
1423 unsigned long flags;
1425 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1427 /* Make sure we're fully resumed: */
1428 if (unlikely(timekeeping_suspended))
1431 clock = real_tk->clock;
1433 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1434 offset = real_tk->cycle_interval;
1436 offset = clocksource_delta(clock->read(clock), clock->cycle_last,
1440 /* Check if there's really nothing to do */
1441 if (offset < real_tk->cycle_interval)
1445 * With NO_HZ we may have to accumulate many cycle_intervals
1446 * (think "ticks") worth of time at once. To do this efficiently,
1447 * we calculate the largest doubling multiple of cycle_intervals
1448 * that is smaller than the offset. We then accumulate that
1449 * chunk in one go, and then try to consume the next smaller
1452 shift = ilog2(offset) - ilog2(tk->cycle_interval);
1453 shift = max(0, shift);
1454 /* Bound shift to one less than what overflows tick_length */
1455 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
1456 shift = min(shift, maxshift);
1457 while (offset >= tk->cycle_interval) {
1458 offset = logarithmic_accumulation(tk, offset, shift,
1460 if (offset < tk->cycle_interval<<shift)
1464 /* correct the clock when NTP error is too big */
1465 timekeeping_adjust(tk, offset);
1468 * XXX This can be killed once everyone converts
1469 * to the new update_vsyscall.
1471 old_vsyscall_fixup(tk);
1474 * Finally, make sure that after the rounding
1475 * xtime_nsec isn't larger than NSEC_PER_SEC
1477 clock_set |= accumulate_nsecs_to_secs(tk);
1479 write_seqcount_begin(&tk_core.seq);
1480 /* Update clock->cycle_last with the new value */
1481 clock->cycle_last = tk->cycle_last;
1483 * Update the real timekeeper.
1485 * We could avoid this memcpy by switching pointers, but that
1486 * requires changes to all other timekeeper usage sites as
1487 * well, i.e. move the timekeeper pointer getter into the
1488 * spinlocked/seqcount protected sections. And we trade this
1489 * memcpy under the tk_core.seq against one before we start
1492 memcpy(real_tk, tk, sizeof(*tk));
1493 timekeeping_update(real_tk, clock_set);
1494 write_seqcount_end(&tk_core.seq);
1496 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1498 /* Have to call _delayed version, since in irq context*/
1499 clock_was_set_delayed();
1503 * getboottime - Return the real time of system boot.
1504 * @ts: pointer to the timespec to be set
1506 * Returns the wall-time of boot in a timespec.
1508 * This is based on the wall_to_monotonic offset and the total suspend
1509 * time. Calls to settimeofday will affect the value returned (which
1510 * basically means that however wrong your real time clock is at boot time,
1511 * you get the right time here).
1513 void getboottime(struct timespec *ts)
1515 struct timekeeper *tk = &tk_core.timekeeper;
1516 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
1518 *ts = ktime_to_timespec(t);
1520 EXPORT_SYMBOL_GPL(getboottime);
1522 unsigned long get_seconds(void)
1524 struct timekeeper *tk = &tk_core.timekeeper;
1526 return tk->xtime_sec;
1528 EXPORT_SYMBOL(get_seconds);
1530 struct timespec __current_kernel_time(void)
1532 struct timekeeper *tk = &tk_core.timekeeper;
1534 return timespec64_to_timespec(tk_xtime(tk));
1537 struct timespec current_kernel_time(void)
1539 struct timekeeper *tk = &tk_core.timekeeper;
1540 struct timespec64 now;
1544 seq = read_seqcount_begin(&tk_core.seq);
1547 } while (read_seqcount_retry(&tk_core.seq, seq));
1549 return timespec64_to_timespec(now);
1551 EXPORT_SYMBOL(current_kernel_time);
1553 struct timespec get_monotonic_coarse(void)
1555 struct timekeeper *tk = &tk_core.timekeeper;
1556 struct timespec64 now, mono;
1560 seq = read_seqcount_begin(&tk_core.seq);
1563 mono = tk->wall_to_monotonic;
1564 } while (read_seqcount_retry(&tk_core.seq, seq));
1566 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
1567 now.tv_nsec + mono.tv_nsec);
1569 return timespec64_to_timespec(now);
1573 * Must hold jiffies_lock
1575 void do_timer(unsigned long ticks)
1577 jiffies_64 += ticks;
1578 calc_global_load(ticks);
1582 * ktime_get_update_offsets_tick - hrtimer helper
1583 * @offs_real: pointer to storage for monotonic -> realtime offset
1584 * @offs_boot: pointer to storage for monotonic -> boottime offset
1585 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1587 * Returns monotonic time at last tick and various offsets
1589 ktime_t ktime_get_update_offsets_tick(ktime_t *offs_real, ktime_t *offs_boot,
1592 struct timekeeper *tk = &tk_core.timekeeper;
1598 seq = read_seqcount_begin(&tk_core.seq);
1600 base = tk->base_mono;
1601 nsecs = tk->xtime_nsec >> tk->shift;
1603 *offs_real = tk->offs_real;
1604 *offs_boot = tk->offs_boot;
1605 *offs_tai = tk->offs_tai;
1606 } while (read_seqcount_retry(&tk_core.seq, seq));
1608 return ktime_add_ns(base, nsecs);
1611 #ifdef CONFIG_HIGH_RES_TIMERS
1613 * ktime_get_update_offsets_now - hrtimer helper
1614 * @offs_real: pointer to storage for monotonic -> realtime offset
1615 * @offs_boot: pointer to storage for monotonic -> boottime offset
1616 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1618 * Returns current monotonic time and updates the offsets
1619 * Called from hrtimer_interrupt() or retrigger_next_event()
1621 ktime_t ktime_get_update_offsets_now(ktime_t *offs_real, ktime_t *offs_boot,
1624 struct timekeeper *tk = &tk_core.timekeeper;
1630 seq = read_seqcount_begin(&tk_core.seq);
1632 base = tk->base_mono;
1633 nsecs = timekeeping_get_ns(tk);
1635 *offs_real = tk->offs_real;
1636 *offs_boot = tk->offs_boot;
1637 *offs_tai = tk->offs_tai;
1638 } while (read_seqcount_retry(&tk_core.seq, seq));
1640 return ktime_add_ns(base, nsecs);
1645 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1647 int do_adjtimex(struct timex *txc)
1649 struct timekeeper *tk = &tk_core.timekeeper;
1650 unsigned long flags;
1651 struct timespec64 ts;
1655 /* Validate the data before disabling interrupts */
1656 ret = ntp_validate_timex(txc);
1660 if (txc->modes & ADJ_SETOFFSET) {
1661 struct timespec delta;
1662 delta.tv_sec = txc->time.tv_sec;
1663 delta.tv_nsec = txc->time.tv_usec;
1664 if (!(txc->modes & ADJ_NANO))
1665 delta.tv_nsec *= 1000;
1666 ret = timekeeping_inject_offset(&delta);
1671 getnstimeofday64(&ts);
1673 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1674 write_seqcount_begin(&tk_core.seq);
1676 orig_tai = tai = tk->tai_offset;
1677 ret = __do_adjtimex(txc, &ts, &tai);
1679 if (tai != orig_tai) {
1680 __timekeeping_set_tai_offset(tk, tai);
1681 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1683 write_seqcount_end(&tk_core.seq);
1684 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1686 if (tai != orig_tai)
1689 ntp_notify_cmos_timer();
1694 #ifdef CONFIG_NTP_PPS
1696 * hardpps() - Accessor function to NTP __hardpps function
1698 void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
1700 unsigned long flags;
1702 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1703 write_seqcount_begin(&tk_core.seq);
1705 __hardpps(phase_ts, raw_ts);
1707 write_seqcount_end(&tk_core.seq);
1708 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1710 EXPORT_SYMBOL(hardpps);
1714 * xtime_update() - advances the timekeeping infrastructure
1715 * @ticks: number of ticks, that have elapsed since the last call.
1717 * Must be called with interrupts disabled.
1719 void xtime_update(unsigned long ticks)
1721 write_seqlock(&jiffies_lock);
1723 write_sequnlock(&jiffies_lock);