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/nmi.h>
18 #include <linux/sched.h>
19 #include <linux/sched/loadavg.h>
20 #include <linux/syscore_ops.h>
21 #include <linux/clocksource.h>
22 #include <linux/jiffies.h>
23 #include <linux/time.h>
24 #include <linux/tick.h>
25 #include <linux/stop_machine.h>
26 #include <linux/pvclock_gtod.h>
27 #include <linux/compiler.h>
29 #include "tick-internal.h"
30 #include "ntp_internal.h"
31 #include "timekeeping_internal.h"
33 #define TK_CLEAR_NTP (1 << 0)
34 #define TK_MIRROR (1 << 1)
35 #define TK_CLOCK_WAS_SET (1 << 2)
38 * The most important data for readout fits into a single 64 byte
43 struct timekeeper timekeeper;
44 } tk_core ____cacheline_aligned;
46 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
47 static struct timekeeper shadow_timekeeper;
50 * struct tk_fast - NMI safe timekeeper
51 * @seq: Sequence counter for protecting updates. The lowest bit
52 * is the index for the tk_read_base array
53 * @base: tk_read_base array. Access is indexed by the lowest bit of
56 * See @update_fast_timekeeper() below.
60 struct tk_read_base base[2];
63 /* Suspend-time cycles value for halted fast timekeeper. */
64 static u64 cycles_at_suspend;
66 static u64 dummy_clock_read(struct clocksource *cs)
68 return cycles_at_suspend;
71 static struct clocksource dummy_clock = {
72 .read = dummy_clock_read,
75 static struct tk_fast tk_fast_mono ____cacheline_aligned = {
76 .base[0] = { .clock = &dummy_clock, },
77 .base[1] = { .clock = &dummy_clock, },
80 static struct tk_fast tk_fast_raw ____cacheline_aligned = {
81 .base[0] = { .clock = &dummy_clock, },
82 .base[1] = { .clock = &dummy_clock, },
85 /* flag for if timekeeping is suspended */
86 int __read_mostly timekeeping_suspended;
88 static inline void tk_normalize_xtime(struct timekeeper *tk)
90 while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
91 tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
94 while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
95 tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
100 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
102 struct timespec64 ts;
104 ts.tv_sec = tk->xtime_sec;
105 ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
109 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
111 tk->xtime_sec = ts->tv_sec;
112 tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
115 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
117 tk->xtime_sec += ts->tv_sec;
118 tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
119 tk_normalize_xtime(tk);
122 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
124 struct timespec64 tmp;
127 * Verify consistency of: offset_real = -wall_to_monotonic
128 * before modifying anything
130 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
131 -tk->wall_to_monotonic.tv_nsec);
132 WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
133 tk->wall_to_monotonic = wtm;
134 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
135 tk->offs_real = timespec64_to_ktime(tmp);
136 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
139 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
141 tk->offs_boot = ktime_add(tk->offs_boot, delta);
145 * tk_clock_read - atomic clocksource read() helper
147 * This helper is necessary to use in the read paths because, while the
148 * seqlock ensures we don't return a bad value while structures are updated,
149 * it doesn't protect from potential crashes. There is the possibility that
150 * the tkr's clocksource may change between the read reference, and the
151 * clock reference passed to the read function. This can cause crashes if
152 * the wrong clocksource is passed to the wrong read function.
153 * This isn't necessary to use when holding the timekeeper_lock or doing
154 * a read of the fast-timekeeper tkrs (which is protected by its own locking
157 static inline u64 tk_clock_read(struct tk_read_base *tkr)
159 struct clocksource *clock = READ_ONCE(tkr->clock);
161 return clock->read(clock);
164 #ifdef CONFIG_DEBUG_TIMEKEEPING
165 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
167 static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
170 u64 max_cycles = tk->tkr_mono.clock->max_cycles;
171 const char *name = tk->tkr_mono.clock->name;
173 if (offset > max_cycles) {
174 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
175 offset, name, max_cycles);
176 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
178 if (offset > (max_cycles >> 1)) {
179 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
180 offset, name, max_cycles >> 1);
181 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
185 if (tk->underflow_seen) {
186 if (jiffies - tk->last_warning > WARNING_FREQ) {
187 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
188 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
189 printk_deferred(" Your kernel is probably still fine.\n");
190 tk->last_warning = jiffies;
192 tk->underflow_seen = 0;
195 if (tk->overflow_seen) {
196 if (jiffies - tk->last_warning > WARNING_FREQ) {
197 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
198 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
199 printk_deferred(" Your kernel is probably still fine.\n");
200 tk->last_warning = jiffies;
202 tk->overflow_seen = 0;
206 static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
208 struct timekeeper *tk = &tk_core.timekeeper;
209 u64 now, last, mask, max, delta;
213 * Since we're called holding a seqlock, the data may shift
214 * under us while we're doing the calculation. This can cause
215 * false positives, since we'd note a problem but throw the
216 * results away. So nest another seqlock here to atomically
217 * grab the points we are checking with.
220 seq = read_seqcount_begin(&tk_core.seq);
221 now = tk_clock_read(tkr);
222 last = tkr->cycle_last;
224 max = tkr->clock->max_cycles;
225 } while (read_seqcount_retry(&tk_core.seq, seq));
227 delta = clocksource_delta(now, last, mask);
230 * Try to catch underflows by checking if we are seeing small
231 * mask-relative negative values.
233 if (unlikely((~delta & mask) < (mask >> 3))) {
234 tk->underflow_seen = 1;
238 /* Cap delta value to the max_cycles values to avoid mult overflows */
239 if (unlikely(delta > max)) {
240 tk->overflow_seen = 1;
241 delta = tkr->clock->max_cycles;
247 static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
250 static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
252 u64 cycle_now, delta;
254 /* read clocksource */
255 cycle_now = tk_clock_read(tkr);
257 /* calculate the delta since the last update_wall_time */
258 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
265 * tk_setup_internals - Set up internals to use clocksource clock.
267 * @tk: The target timekeeper to setup.
268 * @clock: Pointer to clocksource.
270 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
271 * pair and interval request.
273 * Unless you're the timekeeping code, you should not be using this!
275 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
278 u64 tmp, ntpinterval;
279 struct clocksource *old_clock;
281 ++tk->cs_was_changed_seq;
282 old_clock = tk->tkr_mono.clock;
283 tk->tkr_mono.clock = clock;
284 tk->tkr_mono.mask = clock->mask;
285 tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
287 tk->tkr_raw.clock = clock;
288 tk->tkr_raw.mask = clock->mask;
289 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
291 /* Do the ns -> cycle conversion first, using original mult */
292 tmp = NTP_INTERVAL_LENGTH;
293 tmp <<= clock->shift;
295 tmp += clock->mult/2;
296 do_div(tmp, clock->mult);
300 interval = (u64) tmp;
301 tk->cycle_interval = interval;
303 /* Go back from cycles -> shifted ns */
304 tk->xtime_interval = interval * clock->mult;
305 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
306 tk->raw_interval = interval * clock->mult;
308 /* if changing clocks, convert xtime_nsec shift units */
310 int shift_change = clock->shift - old_clock->shift;
311 if (shift_change < 0) {
312 tk->tkr_mono.xtime_nsec >>= -shift_change;
313 tk->tkr_raw.xtime_nsec >>= -shift_change;
315 tk->tkr_mono.xtime_nsec <<= shift_change;
316 tk->tkr_raw.xtime_nsec <<= shift_change;
320 tk->tkr_mono.shift = clock->shift;
321 tk->tkr_raw.shift = clock->shift;
324 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
325 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
328 * The timekeeper keeps its own mult values for the currently
329 * active clocksource. These value will be adjusted via NTP
330 * to counteract clock drifting.
332 tk->tkr_mono.mult = clock->mult;
333 tk->tkr_raw.mult = clock->mult;
334 tk->ntp_err_mult = 0;
335 tk->skip_second_overflow = 0;
338 /* Timekeeper helper functions. */
340 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
341 static u32 default_arch_gettimeoffset(void) { return 0; }
342 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
344 static inline u32 arch_gettimeoffset(void) { return 0; }
347 static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr, u64 delta)
351 nsec = delta * tkr->mult + tkr->xtime_nsec;
354 /* If arch requires, add in get_arch_timeoffset() */
355 return nsec + arch_gettimeoffset();
358 static inline u64 timekeeping_get_ns(struct tk_read_base *tkr)
362 delta = timekeeping_get_delta(tkr);
363 return timekeeping_delta_to_ns(tkr, delta);
366 static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr, u64 cycles)
370 /* calculate the delta since the last update_wall_time */
371 delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
372 return timekeeping_delta_to_ns(tkr, delta);
376 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
377 * @tkr: Timekeeping readout base from which we take the update
379 * We want to use this from any context including NMI and tracing /
380 * instrumenting the timekeeping code itself.
382 * Employ the latch technique; see @raw_write_seqcount_latch.
384 * So if a NMI hits the update of base[0] then it will use base[1]
385 * which is still consistent. In the worst case this can result is a
386 * slightly wrong timestamp (a few nanoseconds). See
387 * @ktime_get_mono_fast_ns.
389 static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
391 struct tk_read_base *base = tkf->base;
393 /* Force readers off to base[1] */
394 raw_write_seqcount_latch(&tkf->seq);
397 memcpy(base, tkr, sizeof(*base));
399 /* Force readers back to base[0] */
400 raw_write_seqcount_latch(&tkf->seq);
403 memcpy(base + 1, base, sizeof(*base));
407 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
409 * This timestamp is not guaranteed to be monotonic across an update.
410 * The timestamp is calculated by:
412 * now = base_mono + clock_delta * slope
414 * So if the update lowers the slope, readers who are forced to the
415 * not yet updated second array are still using the old steeper slope.
424 * |12345678---> reader order
430 * So reader 6 will observe time going backwards versus reader 5.
432 * While other CPUs are likely to be able observe that, the only way
433 * for a CPU local observation is when an NMI hits in the middle of
434 * the update. Timestamps taken from that NMI context might be ahead
435 * of the following timestamps. Callers need to be aware of that and
438 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
440 struct tk_read_base *tkr;
445 seq = raw_read_seqcount_latch(&tkf->seq);
446 tkr = tkf->base + (seq & 0x01);
447 now = ktime_to_ns(tkr->base);
449 now += timekeeping_delta_to_ns(tkr,
454 } while (read_seqcount_retry(&tkf->seq, seq));
459 u64 ktime_get_mono_fast_ns(void)
461 return __ktime_get_fast_ns(&tk_fast_mono);
463 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
465 u64 ktime_get_raw_fast_ns(void)
467 return __ktime_get_fast_ns(&tk_fast_raw);
469 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
472 * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
474 * To keep it NMI safe since we're accessing from tracing, we're not using a
475 * separate timekeeper with updates to monotonic clock and boot offset
476 * protected with seqlocks. This has the following minor side effects:
478 * (1) Its possible that a timestamp be taken after the boot offset is updated
479 * but before the timekeeper is updated. If this happens, the new boot offset
480 * is added to the old timekeeping making the clock appear to update slightly
483 * timekeeping_inject_sleeptime64()
484 * __timekeeping_inject_sleeptime(tk, delta);
486 * timekeeping_update(tk, TK_CLEAR_NTP...);
488 * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
489 * partially updated. Since the tk->offs_boot update is a rare event, this
490 * should be a rare occurrence which postprocessing should be able to handle.
492 u64 notrace ktime_get_boot_fast_ns(void)
494 struct timekeeper *tk = &tk_core.timekeeper;
496 return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
498 EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
502 * See comment for __ktime_get_fast_ns() vs. timestamp ordering
504 static __always_inline u64 __ktime_get_real_fast_ns(struct tk_fast *tkf)
506 struct tk_read_base *tkr;
511 seq = raw_read_seqcount_latch(&tkf->seq);
512 tkr = tkf->base + (seq & 0x01);
513 now = ktime_to_ns(tkr->base_real);
515 now += timekeeping_delta_to_ns(tkr,
520 } while (read_seqcount_retry(&tkf->seq, seq));
526 * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime.
528 u64 ktime_get_real_fast_ns(void)
530 return __ktime_get_real_fast_ns(&tk_fast_mono);
532 EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
535 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
536 * @tk: Timekeeper to snapshot.
538 * It generally is unsafe to access the clocksource after timekeeping has been
539 * suspended, so take a snapshot of the readout base of @tk and use it as the
540 * fast timekeeper's readout base while suspended. It will return the same
541 * number of cycles every time until timekeeping is resumed at which time the
542 * proper readout base for the fast timekeeper will be restored automatically.
544 static void halt_fast_timekeeper(struct timekeeper *tk)
546 static struct tk_read_base tkr_dummy;
547 struct tk_read_base *tkr = &tk->tkr_mono;
549 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
550 cycles_at_suspend = tk_clock_read(tkr);
551 tkr_dummy.clock = &dummy_clock;
552 tkr_dummy.base_real = tkr->base + tk->offs_real;
553 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
556 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
557 tkr_dummy.clock = &dummy_clock;
558 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
561 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
563 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
565 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
569 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
571 int pvclock_gtod_register_notifier(struct notifier_block *nb)
573 struct timekeeper *tk = &tk_core.timekeeper;
577 raw_spin_lock_irqsave(&timekeeper_lock, flags);
578 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
579 update_pvclock_gtod(tk, true);
580 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
584 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
587 * pvclock_gtod_unregister_notifier - unregister a pvclock
588 * timedata update listener
590 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
595 raw_spin_lock_irqsave(&timekeeper_lock, flags);
596 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
597 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
601 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
604 * tk_update_leap_state - helper to update the next_leap_ktime
606 static inline void tk_update_leap_state(struct timekeeper *tk)
608 tk->next_leap_ktime = ntp_get_next_leap();
609 if (tk->next_leap_ktime != KTIME_MAX)
610 /* Convert to monotonic time */
611 tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
615 * Update the ktime_t based scalar nsec members of the timekeeper
617 static inline void tk_update_ktime_data(struct timekeeper *tk)
623 * The xtime based monotonic readout is:
624 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
625 * The ktime based monotonic readout is:
626 * nsec = base_mono + now();
627 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
629 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
630 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
631 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
634 * The sum of the nanoseconds portions of xtime and
635 * wall_to_monotonic can be greater/equal one second. Take
636 * this into account before updating tk->ktime_sec.
638 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
639 if (nsec >= NSEC_PER_SEC)
641 tk->ktime_sec = seconds;
643 /* Update the monotonic raw base */
644 tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC);
647 /* must hold timekeeper_lock */
648 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
650 if (action & TK_CLEAR_NTP) {
655 tk_update_leap_state(tk);
656 tk_update_ktime_data(tk);
659 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
661 tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real;
662 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
663 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
665 if (action & TK_CLOCK_WAS_SET)
666 tk->clock_was_set_seq++;
668 * The mirroring of the data to the shadow-timekeeper needs
669 * to happen last here to ensure we don't over-write the
670 * timekeeper structure on the next update with stale data
672 if (action & TK_MIRROR)
673 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
674 sizeof(tk_core.timekeeper));
678 * timekeeping_forward_now - update clock to the current time
680 * Forward the current clock to update its state since the last call to
681 * update_wall_time(). This is useful before significant clock changes,
682 * as it avoids having to deal with this time offset explicitly.
684 static void timekeeping_forward_now(struct timekeeper *tk)
686 u64 cycle_now, delta;
688 cycle_now = tk_clock_read(&tk->tkr_mono);
689 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
690 tk->tkr_mono.cycle_last = cycle_now;
691 tk->tkr_raw.cycle_last = cycle_now;
693 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
695 /* If arch requires, add in get_arch_timeoffset() */
696 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
699 tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;
701 /* If arch requires, add in get_arch_timeoffset() */
702 tk->tkr_raw.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_raw.shift;
704 tk_normalize_xtime(tk);
708 * __getnstimeofday64 - Returns the time of day in a timespec64.
709 * @ts: pointer to the timespec to be set
711 * Updates the time of day in the timespec.
712 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
714 int __getnstimeofday64(struct timespec64 *ts)
716 struct timekeeper *tk = &tk_core.timekeeper;
721 seq = read_seqcount_begin(&tk_core.seq);
723 ts->tv_sec = tk->xtime_sec;
724 nsecs = timekeeping_get_ns(&tk->tkr_mono);
726 } while (read_seqcount_retry(&tk_core.seq, seq));
729 timespec64_add_ns(ts, nsecs);
732 * Do not bail out early, in case there were callers still using
733 * the value, even in the face of the WARN_ON.
735 if (unlikely(timekeeping_suspended))
739 EXPORT_SYMBOL(__getnstimeofday64);
742 * getnstimeofday64 - Returns the time of day in a timespec64.
743 * @ts: pointer to the timespec64 to be set
745 * Returns the time of day in a timespec64 (WARN if suspended).
747 void getnstimeofday64(struct timespec64 *ts)
749 WARN_ON(__getnstimeofday64(ts));
751 EXPORT_SYMBOL(getnstimeofday64);
753 ktime_t ktime_get(void)
755 struct timekeeper *tk = &tk_core.timekeeper;
760 WARN_ON(timekeeping_suspended);
763 seq = read_seqcount_begin(&tk_core.seq);
764 base = tk->tkr_mono.base;
765 nsecs = timekeeping_get_ns(&tk->tkr_mono);
767 } while (read_seqcount_retry(&tk_core.seq, seq));
769 return ktime_add_ns(base, nsecs);
771 EXPORT_SYMBOL_GPL(ktime_get);
773 u32 ktime_get_resolution_ns(void)
775 struct timekeeper *tk = &tk_core.timekeeper;
779 WARN_ON(timekeeping_suspended);
782 seq = read_seqcount_begin(&tk_core.seq);
783 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
784 } while (read_seqcount_retry(&tk_core.seq, seq));
788 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
790 static ktime_t *offsets[TK_OFFS_MAX] = {
791 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
792 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
793 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
796 ktime_t ktime_get_with_offset(enum tk_offsets offs)
798 struct timekeeper *tk = &tk_core.timekeeper;
800 ktime_t base, *offset = offsets[offs];
803 WARN_ON(timekeeping_suspended);
806 seq = read_seqcount_begin(&tk_core.seq);
807 base = ktime_add(tk->tkr_mono.base, *offset);
808 nsecs = timekeeping_get_ns(&tk->tkr_mono);
810 } while (read_seqcount_retry(&tk_core.seq, seq));
812 return ktime_add_ns(base, nsecs);
815 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
818 * ktime_mono_to_any() - convert mononotic time to any other time
819 * @tmono: time to convert.
820 * @offs: which offset to use
822 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
824 ktime_t *offset = offsets[offs];
829 seq = read_seqcount_begin(&tk_core.seq);
830 tconv = ktime_add(tmono, *offset);
831 } while (read_seqcount_retry(&tk_core.seq, seq));
835 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
838 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
840 ktime_t ktime_get_raw(void)
842 struct timekeeper *tk = &tk_core.timekeeper;
848 seq = read_seqcount_begin(&tk_core.seq);
849 base = tk->tkr_raw.base;
850 nsecs = timekeeping_get_ns(&tk->tkr_raw);
852 } while (read_seqcount_retry(&tk_core.seq, seq));
854 return ktime_add_ns(base, nsecs);
856 EXPORT_SYMBOL_GPL(ktime_get_raw);
859 * ktime_get_ts64 - get the monotonic clock in timespec64 format
860 * @ts: pointer to timespec variable
862 * The function calculates the monotonic clock from the realtime
863 * clock and the wall_to_monotonic offset and stores the result
864 * in normalized timespec64 format in the variable pointed to by @ts.
866 void ktime_get_ts64(struct timespec64 *ts)
868 struct timekeeper *tk = &tk_core.timekeeper;
869 struct timespec64 tomono;
873 WARN_ON(timekeeping_suspended);
876 seq = read_seqcount_begin(&tk_core.seq);
877 ts->tv_sec = tk->xtime_sec;
878 nsec = timekeeping_get_ns(&tk->tkr_mono);
879 tomono = tk->wall_to_monotonic;
881 } while (read_seqcount_retry(&tk_core.seq, seq));
883 ts->tv_sec += tomono.tv_sec;
885 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
887 EXPORT_SYMBOL_GPL(ktime_get_ts64);
890 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
892 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
893 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
894 * works on both 32 and 64 bit systems. On 32 bit systems the readout
895 * covers ~136 years of uptime which should be enough to prevent
896 * premature wrap arounds.
898 time64_t ktime_get_seconds(void)
900 struct timekeeper *tk = &tk_core.timekeeper;
902 WARN_ON(timekeeping_suspended);
903 return tk->ktime_sec;
905 EXPORT_SYMBOL_GPL(ktime_get_seconds);
908 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
910 * Returns the wall clock seconds since 1970. This replaces the
911 * get_seconds() interface which is not y2038 safe on 32bit systems.
913 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
914 * 32bit systems the access must be protected with the sequence
915 * counter to provide "atomic" access to the 64bit tk->xtime_sec
918 time64_t ktime_get_real_seconds(void)
920 struct timekeeper *tk = &tk_core.timekeeper;
924 if (IS_ENABLED(CONFIG_64BIT))
925 return tk->xtime_sec;
928 seq = read_seqcount_begin(&tk_core.seq);
929 seconds = tk->xtime_sec;
931 } while (read_seqcount_retry(&tk_core.seq, seq));
935 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
938 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
939 * but without the sequence counter protect. This internal function
940 * is called just when timekeeping lock is already held.
942 time64_t __ktime_get_real_seconds(void)
944 struct timekeeper *tk = &tk_core.timekeeper;
946 return tk->xtime_sec;
950 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
951 * @systime_snapshot: pointer to struct receiving the system time snapshot
953 void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
955 struct timekeeper *tk = &tk_core.timekeeper;
963 WARN_ON_ONCE(timekeeping_suspended);
966 seq = read_seqcount_begin(&tk_core.seq);
967 now = tk_clock_read(&tk->tkr_mono);
968 systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
969 systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
970 base_real = ktime_add(tk->tkr_mono.base,
971 tk_core.timekeeper.offs_real);
972 base_raw = tk->tkr_raw.base;
973 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
974 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
975 } while (read_seqcount_retry(&tk_core.seq, seq));
977 systime_snapshot->cycles = now;
978 systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
979 systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
981 EXPORT_SYMBOL_GPL(ktime_get_snapshot);
983 /* Scale base by mult/div checking for overflow */
984 static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
988 tmp = div64_u64_rem(*base, div, &rem);
990 if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
991 ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
1002 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
1003 * @history: Snapshot representing start of history
1004 * @partial_history_cycles: Cycle offset into history (fractional part)
1005 * @total_history_cycles: Total history length in cycles
1006 * @discontinuity: True indicates clock was set on history period
1007 * @ts: Cross timestamp that should be adjusted using
1008 * partial/total ratio
1010 * Helper function used by get_device_system_crosststamp() to correct the
1011 * crosstimestamp corresponding to the start of the current interval to the
1012 * system counter value (timestamp point) provided by the driver. The
1013 * total_history_* quantities are the total history starting at the provided
1014 * reference point and ending at the start of the current interval. The cycle
1015 * count between the driver timestamp point and the start of the current
1016 * interval is partial_history_cycles.
1018 static int adjust_historical_crosststamp(struct system_time_snapshot *history,
1019 u64 partial_history_cycles,
1020 u64 total_history_cycles,
1022 struct system_device_crosststamp *ts)
1024 struct timekeeper *tk = &tk_core.timekeeper;
1025 u64 corr_raw, corr_real;
1026 bool interp_forward;
1029 if (total_history_cycles == 0 || partial_history_cycles == 0)
1032 /* Interpolate shortest distance from beginning or end of history */
1033 interp_forward = partial_history_cycles > total_history_cycles / 2;
1034 partial_history_cycles = interp_forward ?
1035 total_history_cycles - partial_history_cycles :
1036 partial_history_cycles;
1039 * Scale the monotonic raw time delta by:
1040 * partial_history_cycles / total_history_cycles
1042 corr_raw = (u64)ktime_to_ns(
1043 ktime_sub(ts->sys_monoraw, history->raw));
1044 ret = scale64_check_overflow(partial_history_cycles,
1045 total_history_cycles, &corr_raw);
1050 * If there is a discontinuity in the history, scale monotonic raw
1052 * mult(real)/mult(raw) yielding the realtime correction
1053 * Otherwise, calculate the realtime correction similar to monotonic
1056 if (discontinuity) {
1057 corr_real = mul_u64_u32_div
1058 (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1060 corr_real = (u64)ktime_to_ns(
1061 ktime_sub(ts->sys_realtime, history->real));
1062 ret = scale64_check_overflow(partial_history_cycles,
1063 total_history_cycles, &corr_real);
1068 /* Fixup monotonic raw and real time time values */
1069 if (interp_forward) {
1070 ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1071 ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1073 ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1074 ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1081 * cycle_between - true if test occurs chronologically between before and after
1083 static bool cycle_between(u64 before, u64 test, u64 after)
1085 if (test > before && test < after)
1087 if (test < before && before > after)
1093 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1094 * @get_time_fn: Callback to get simultaneous device time and
1095 * system counter from the device driver
1096 * @ctx: Context passed to get_time_fn()
1097 * @history_begin: Historical reference point used to interpolate system
1098 * time when counter provided by the driver is before the current interval
1099 * @xtstamp: Receives simultaneously captured system and device time
1101 * Reads a timestamp from a device and correlates it to system time
1103 int get_device_system_crosststamp(int (*get_time_fn)
1104 (ktime_t *device_time,
1105 struct system_counterval_t *sys_counterval,
1108 struct system_time_snapshot *history_begin,
1109 struct system_device_crosststamp *xtstamp)
1111 struct system_counterval_t system_counterval;
1112 struct timekeeper *tk = &tk_core.timekeeper;
1113 u64 cycles, now, interval_start;
1114 unsigned int clock_was_set_seq = 0;
1115 ktime_t base_real, base_raw;
1116 u64 nsec_real, nsec_raw;
1117 u8 cs_was_changed_seq;
1123 seq = read_seqcount_begin(&tk_core.seq);
1125 * Try to synchronously capture device time and a system
1126 * counter value calling back into the device driver
1128 ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1133 * Verify that the clocksource associated with the captured
1134 * system counter value is the same as the currently installed
1135 * timekeeper clocksource
1137 if (tk->tkr_mono.clock != system_counterval.cs)
1139 cycles = system_counterval.cycles;
1142 * Check whether the system counter value provided by the
1143 * device driver is on the current timekeeping interval.
1145 now = tk_clock_read(&tk->tkr_mono);
1146 interval_start = tk->tkr_mono.cycle_last;
1147 if (!cycle_between(interval_start, cycles, now)) {
1148 clock_was_set_seq = tk->clock_was_set_seq;
1149 cs_was_changed_seq = tk->cs_was_changed_seq;
1150 cycles = interval_start;
1156 base_real = ktime_add(tk->tkr_mono.base,
1157 tk_core.timekeeper.offs_real);
1158 base_raw = tk->tkr_raw.base;
1160 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1161 system_counterval.cycles);
1162 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1163 system_counterval.cycles);
1164 } while (read_seqcount_retry(&tk_core.seq, seq));
1166 xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1167 xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1170 * Interpolate if necessary, adjusting back from the start of the
1174 u64 partial_history_cycles, total_history_cycles;
1178 * Check that the counter value occurs after the provided
1179 * history reference and that the history doesn't cross a
1180 * clocksource change
1182 if (!history_begin ||
1183 !cycle_between(history_begin->cycles,
1184 system_counterval.cycles, cycles) ||
1185 history_begin->cs_was_changed_seq != cs_was_changed_seq)
1187 partial_history_cycles = cycles - system_counterval.cycles;
1188 total_history_cycles = cycles - history_begin->cycles;
1190 history_begin->clock_was_set_seq != clock_was_set_seq;
1192 ret = adjust_historical_crosststamp(history_begin,
1193 partial_history_cycles,
1194 total_history_cycles,
1195 discontinuity, xtstamp);
1202 EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1205 * do_gettimeofday - Returns the time of day in a timeval
1206 * @tv: pointer to the timeval to be set
1208 * NOTE: Users should be converted to using getnstimeofday()
1210 void do_gettimeofday(struct timeval *tv)
1212 struct timespec64 now;
1214 getnstimeofday64(&now);
1215 tv->tv_sec = now.tv_sec;
1216 tv->tv_usec = now.tv_nsec/1000;
1218 EXPORT_SYMBOL(do_gettimeofday);
1221 * do_settimeofday64 - Sets the time of day.
1222 * @ts: pointer to the timespec64 variable containing the new time
1224 * Sets the time of day to the new time and update NTP and notify hrtimers
1226 int do_settimeofday64(const struct timespec64 *ts)
1228 struct timekeeper *tk = &tk_core.timekeeper;
1229 struct timespec64 ts_delta, xt;
1230 unsigned long flags;
1233 if (!timespec64_valid_strict(ts))
1236 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1237 write_seqcount_begin(&tk_core.seq);
1239 timekeeping_forward_now(tk);
1242 ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
1243 ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
1245 if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1250 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1252 tk_set_xtime(tk, ts);
1254 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1256 write_seqcount_end(&tk_core.seq);
1257 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1259 /* signal hrtimers about time change */
1264 EXPORT_SYMBOL(do_settimeofday64);
1267 * timekeeping_inject_offset - Adds or subtracts from the current time.
1268 * @tv: pointer to the timespec variable containing the offset
1270 * Adds or subtracts an offset value from the current time.
1272 static int timekeeping_inject_offset(struct timespec64 *ts)
1274 struct timekeeper *tk = &tk_core.timekeeper;
1275 unsigned long flags;
1276 struct timespec64 tmp;
1279 if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
1282 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1283 write_seqcount_begin(&tk_core.seq);
1285 timekeeping_forward_now(tk);
1287 /* Make sure the proposed value is valid */
1288 tmp = timespec64_add(tk_xtime(tk), *ts);
1289 if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
1290 !timespec64_valid_strict(&tmp)) {
1295 tk_xtime_add(tk, ts);
1296 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *ts));
1298 error: /* even if we error out, we forwarded the time, so call update */
1299 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1301 write_seqcount_end(&tk_core.seq);
1302 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1304 /* signal hrtimers about time change */
1311 * Indicates if there is an offset between the system clock and the hardware
1312 * clock/persistent clock/rtc.
1314 int persistent_clock_is_local;
1317 * Adjust the time obtained from the CMOS to be UTC time instead of
1320 * This is ugly, but preferable to the alternatives. Otherwise we
1321 * would either need to write a program to do it in /etc/rc (and risk
1322 * confusion if the program gets run more than once; it would also be
1323 * hard to make the program warp the clock precisely n hours) or
1324 * compile in the timezone information into the kernel. Bad, bad....
1328 * The best thing to do is to keep the CMOS clock in universal time (UTC)
1329 * as real UNIX machines always do it. This avoids all headaches about
1330 * daylight saving times and warping kernel clocks.
1332 void timekeeping_warp_clock(void)
1334 if (sys_tz.tz_minuteswest != 0) {
1335 struct timespec64 adjust;
1337 persistent_clock_is_local = 1;
1338 adjust.tv_sec = sys_tz.tz_minuteswest * 60;
1340 timekeeping_inject_offset(&adjust);
1345 * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
1348 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1350 tk->tai_offset = tai_offset;
1351 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1355 * change_clocksource - Swaps clocksources if a new one is available
1357 * Accumulates current time interval and initializes new clocksource
1359 static int change_clocksource(void *data)
1361 struct timekeeper *tk = &tk_core.timekeeper;
1362 struct clocksource *new, *old;
1363 unsigned long flags;
1365 new = (struct clocksource *) data;
1367 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1368 write_seqcount_begin(&tk_core.seq);
1370 timekeeping_forward_now(tk);
1372 * If the cs is in module, get a module reference. Succeeds
1373 * for built-in code (owner == NULL) as well.
1375 if (try_module_get(new->owner)) {
1376 if (!new->enable || new->enable(new) == 0) {
1377 old = tk->tkr_mono.clock;
1378 tk_setup_internals(tk, new);
1381 module_put(old->owner);
1383 module_put(new->owner);
1386 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1388 write_seqcount_end(&tk_core.seq);
1389 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1395 * timekeeping_notify - Install a new clock source
1396 * @clock: pointer to the clock source
1398 * This function is called from clocksource.c after a new, better clock
1399 * source has been registered. The caller holds the clocksource_mutex.
1401 int timekeeping_notify(struct clocksource *clock)
1403 struct timekeeper *tk = &tk_core.timekeeper;
1405 if (tk->tkr_mono.clock == clock)
1407 stop_machine(change_clocksource, clock, NULL);
1408 tick_clock_notify();
1409 return tk->tkr_mono.clock == clock ? 0 : -1;
1413 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1414 * @ts: pointer to the timespec64 to be set
1416 * Returns the raw monotonic time (completely un-modified by ntp)
1418 void getrawmonotonic64(struct timespec64 *ts)
1420 struct timekeeper *tk = &tk_core.timekeeper;
1425 seq = read_seqcount_begin(&tk_core.seq);
1426 ts->tv_sec = tk->raw_sec;
1427 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1429 } while (read_seqcount_retry(&tk_core.seq, seq));
1432 timespec64_add_ns(ts, nsecs);
1434 EXPORT_SYMBOL(getrawmonotonic64);
1438 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1440 int timekeeping_valid_for_hres(void)
1442 struct timekeeper *tk = &tk_core.timekeeper;
1447 seq = read_seqcount_begin(&tk_core.seq);
1449 ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1451 } while (read_seqcount_retry(&tk_core.seq, seq));
1457 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1459 u64 timekeeping_max_deferment(void)
1461 struct timekeeper *tk = &tk_core.timekeeper;
1466 seq = read_seqcount_begin(&tk_core.seq);
1468 ret = tk->tkr_mono.clock->max_idle_ns;
1470 } while (read_seqcount_retry(&tk_core.seq, seq));
1476 * read_persistent_clock - Return time from the persistent clock.
1478 * Weak dummy function for arches that do not yet support it.
1479 * Reads the time from the battery backed persistent clock.
1480 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1482 * XXX - Do be sure to remove it once all arches implement it.
1484 void __weak read_persistent_clock(struct timespec *ts)
1490 void __weak read_persistent_clock64(struct timespec64 *ts64)
1494 read_persistent_clock(&ts);
1495 *ts64 = timespec_to_timespec64(ts);
1499 * read_boot_clock64 - Return time of the system start.
1501 * Weak dummy function for arches that do not yet support it.
1502 * Function to read the exact time the system has been started.
1503 * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported.
1505 * XXX - Do be sure to remove it once all arches implement it.
1507 void __weak read_boot_clock64(struct timespec64 *ts)
1513 /* Flag for if timekeeping_resume() has injected sleeptime */
1514 static bool sleeptime_injected;
1516 /* Flag for if there is a persistent clock on this platform */
1517 static bool persistent_clock_exists;
1520 * timekeeping_init - Initializes the clocksource and common timekeeping values
1522 void __init timekeeping_init(void)
1524 struct timekeeper *tk = &tk_core.timekeeper;
1525 struct clocksource *clock;
1526 unsigned long flags;
1527 struct timespec64 now, boot, tmp;
1529 read_persistent_clock64(&now);
1530 if (!timespec64_valid_strict(&now)) {
1531 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1532 " Check your CMOS/BIOS settings.\n");
1535 } else if (now.tv_sec || now.tv_nsec)
1536 persistent_clock_exists = true;
1538 read_boot_clock64(&boot);
1539 if (!timespec64_valid_strict(&boot)) {
1540 pr_warn("WARNING: Boot clock returned invalid value!\n"
1541 " Check your CMOS/BIOS settings.\n");
1546 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1547 write_seqcount_begin(&tk_core.seq);
1550 clock = clocksource_default_clock();
1552 clock->enable(clock);
1553 tk_setup_internals(tk, clock);
1555 tk_set_xtime(tk, &now);
1557 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1558 boot = tk_xtime(tk);
1560 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1561 tk_set_wall_to_mono(tk, tmp);
1563 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1565 write_seqcount_end(&tk_core.seq);
1566 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1569 /* time in seconds when suspend began for persistent clock */
1570 static struct timespec64 timekeeping_suspend_time;
1573 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1574 * @delta: pointer to a timespec delta value
1576 * Takes a timespec offset measuring a suspend interval and properly
1577 * adds the sleep offset to the timekeeping variables.
1579 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1580 struct timespec64 *delta)
1582 if (!timespec64_valid_strict(delta)) {
1583 printk_deferred(KERN_WARNING
1584 "__timekeeping_inject_sleeptime: Invalid "
1585 "sleep delta value!\n");
1588 tk_xtime_add(tk, delta);
1589 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1590 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1591 tk_debug_account_sleep_time(delta);
1594 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1596 * We have three kinds of time sources to use for sleep time
1597 * injection, the preference order is:
1598 * 1) non-stop clocksource
1599 * 2) persistent clock (ie: RTC accessible when irqs are off)
1602 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1603 * If system has neither 1) nor 2), 3) will be used finally.
1606 * If timekeeping has injected sleeptime via either 1) or 2),
1607 * 3) becomes needless, so in this case we don't need to call
1608 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1611 bool timekeeping_rtc_skipresume(void)
1613 return sleeptime_injected;
1617 * 1) can be determined whether to use or not only when doing
1618 * timekeeping_resume() which is invoked after rtc_suspend(),
1619 * so we can't skip rtc_suspend() surely if system has 1).
1621 * But if system has 2), 2) will definitely be used, so in this
1622 * case we don't need to call rtc_suspend(), and this is what
1623 * timekeeping_rtc_skipsuspend() means.
1625 bool timekeeping_rtc_skipsuspend(void)
1627 return persistent_clock_exists;
1631 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1632 * @delta: pointer to a timespec64 delta value
1634 * This hook is for architectures that cannot support read_persistent_clock64
1635 * because their RTC/persistent clock is only accessible when irqs are enabled.
1636 * and also don't have an effective nonstop clocksource.
1638 * This function should only be called by rtc_resume(), and allows
1639 * a suspend offset to be injected into the timekeeping values.
1641 void timekeeping_inject_sleeptime64(struct timespec64 *delta)
1643 struct timekeeper *tk = &tk_core.timekeeper;
1644 unsigned long flags;
1646 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1647 write_seqcount_begin(&tk_core.seq);
1649 timekeeping_forward_now(tk);
1651 __timekeeping_inject_sleeptime(tk, delta);
1653 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1655 write_seqcount_end(&tk_core.seq);
1656 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1658 /* signal hrtimers about time change */
1664 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1666 void timekeeping_resume(void)
1668 struct timekeeper *tk = &tk_core.timekeeper;
1669 struct clocksource *clock = tk->tkr_mono.clock;
1670 unsigned long flags;
1671 struct timespec64 ts_new, ts_delta;
1674 sleeptime_injected = false;
1675 read_persistent_clock64(&ts_new);
1677 clockevents_resume();
1678 clocksource_resume();
1680 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1681 write_seqcount_begin(&tk_core.seq);
1684 * After system resumes, we need to calculate the suspended time and
1685 * compensate it for the OS time. There are 3 sources that could be
1686 * used: Nonstop clocksource during suspend, persistent clock and rtc
1689 * One specific platform may have 1 or 2 or all of them, and the
1690 * preference will be:
1691 * suspend-nonstop clocksource -> persistent clock -> rtc
1692 * The less preferred source will only be tried if there is no better
1693 * usable source. The rtc part is handled separately in rtc core code.
1695 cycle_now = tk_clock_read(&tk->tkr_mono);
1696 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1697 cycle_now > tk->tkr_mono.cycle_last) {
1698 u64 nsec, cyc_delta;
1700 cyc_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
1702 nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift);
1703 ts_delta = ns_to_timespec64(nsec);
1704 sleeptime_injected = true;
1705 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1706 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1707 sleeptime_injected = true;
1710 if (sleeptime_injected)
1711 __timekeeping_inject_sleeptime(tk, &ts_delta);
1713 /* Re-base the last cycle value */
1714 tk->tkr_mono.cycle_last = cycle_now;
1715 tk->tkr_raw.cycle_last = cycle_now;
1718 timekeeping_suspended = 0;
1719 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1720 write_seqcount_end(&tk_core.seq);
1721 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1723 touch_softlockup_watchdog();
1729 int timekeeping_suspend(void)
1731 struct timekeeper *tk = &tk_core.timekeeper;
1732 unsigned long flags;
1733 struct timespec64 delta, delta_delta;
1734 static struct timespec64 old_delta;
1736 read_persistent_clock64(&timekeeping_suspend_time);
1739 * On some systems the persistent_clock can not be detected at
1740 * timekeeping_init by its return value, so if we see a valid
1741 * value returned, update the persistent_clock_exists flag.
1743 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1744 persistent_clock_exists = true;
1746 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1747 write_seqcount_begin(&tk_core.seq);
1748 timekeeping_forward_now(tk);
1749 timekeeping_suspended = 1;
1751 if (persistent_clock_exists) {
1753 * To avoid drift caused by repeated suspend/resumes,
1754 * which each can add ~1 second drift error,
1755 * try to compensate so the difference in system time
1756 * and persistent_clock time stays close to constant.
1758 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1759 delta_delta = timespec64_sub(delta, old_delta);
1760 if (abs(delta_delta.tv_sec) >= 2) {
1762 * if delta_delta is too large, assume time correction
1763 * has occurred and set old_delta to the current delta.
1767 /* Otherwise try to adjust old_system to compensate */
1768 timekeeping_suspend_time =
1769 timespec64_add(timekeeping_suspend_time, delta_delta);
1773 timekeeping_update(tk, TK_MIRROR);
1774 halt_fast_timekeeper(tk);
1775 write_seqcount_end(&tk_core.seq);
1776 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1779 clocksource_suspend();
1780 clockevents_suspend();
1785 /* sysfs resume/suspend bits for timekeeping */
1786 static struct syscore_ops timekeeping_syscore_ops = {
1787 .resume = timekeeping_resume,
1788 .suspend = timekeeping_suspend,
1791 static int __init timekeeping_init_ops(void)
1793 register_syscore_ops(&timekeeping_syscore_ops);
1796 device_initcall(timekeeping_init_ops);
1799 * Apply a multiplier adjustment to the timekeeper
1801 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1805 s64 interval = tk->cycle_interval;
1807 if (mult_adj == 0) {
1809 } else if (mult_adj == -1) {
1810 interval = -interval;
1812 } else if (mult_adj != 1) {
1813 interval *= mult_adj;
1818 * So the following can be confusing.
1820 * To keep things simple, lets assume mult_adj == 1 for now.
1822 * When mult_adj != 1, remember that the interval and offset values
1823 * have been appropriately scaled so the math is the same.
1825 * The basic idea here is that we're increasing the multiplier
1826 * by one, this causes the xtime_interval to be incremented by
1827 * one cycle_interval. This is because:
1828 * xtime_interval = cycle_interval * mult
1829 * So if mult is being incremented by one:
1830 * xtime_interval = cycle_interval * (mult + 1)
1832 * xtime_interval = (cycle_interval * mult) + cycle_interval
1833 * Which can be shortened to:
1834 * xtime_interval += cycle_interval
1836 * So offset stores the non-accumulated cycles. Thus the current
1837 * time (in shifted nanoseconds) is:
1838 * now = (offset * adj) + xtime_nsec
1839 * Now, even though we're adjusting the clock frequency, we have
1840 * to keep time consistent. In other words, we can't jump back
1841 * in time, and we also want to avoid jumping forward in time.
1843 * So given the same offset value, we need the time to be the same
1844 * both before and after the freq adjustment.
1845 * now = (offset * adj_1) + xtime_nsec_1
1846 * now = (offset * adj_2) + xtime_nsec_2
1848 * (offset * adj_1) + xtime_nsec_1 =
1849 * (offset * adj_2) + xtime_nsec_2
1853 * (offset * adj_1) + xtime_nsec_1 =
1854 * (offset * (adj_1+1)) + xtime_nsec_2
1855 * (offset * adj_1) + xtime_nsec_1 =
1856 * (offset * adj_1) + offset + xtime_nsec_2
1857 * Canceling the sides:
1858 * xtime_nsec_1 = offset + xtime_nsec_2
1860 * xtime_nsec_2 = xtime_nsec_1 - offset
1861 * Which simplfies to:
1862 * xtime_nsec -= offset
1864 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1865 /* NTP adjustment caused clocksource mult overflow */
1870 tk->tkr_mono.mult += mult_adj;
1871 tk->xtime_interval += interval;
1872 tk->tkr_mono.xtime_nsec -= offset;
1876 * Adjust the timekeeper's multiplier to the correct frequency
1877 * and also to reduce the accumulated error value.
1879 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1884 * Determine the multiplier from the current NTP tick length.
1885 * Avoid expensive division when the tick length doesn't change.
1887 if (likely(tk->ntp_tick == ntp_tick_length())) {
1888 mult = tk->tkr_mono.mult - tk->ntp_err_mult;
1890 tk->ntp_tick = ntp_tick_length();
1891 mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
1892 tk->xtime_remainder, tk->cycle_interval);
1896 * If the clock is behind the NTP time, increase the multiplier by 1
1897 * to catch up with it. If it's ahead and there was a remainder in the
1898 * tick division, the clock will slow down. Otherwise it will stay
1899 * ahead until the tick length changes to a non-divisible value.
1901 tk->ntp_err_mult = tk->ntp_error > 0 ? 1 : 0;
1902 mult += tk->ntp_err_mult;
1904 timekeeping_apply_adjustment(tk, offset, mult - tk->tkr_mono.mult);
1906 if (unlikely(tk->tkr_mono.clock->maxadj &&
1907 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1908 > tk->tkr_mono.clock->maxadj))) {
1909 printk_once(KERN_WARNING
1910 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1911 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1912 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1916 * It may be possible that when we entered this function, xtime_nsec
1917 * was very small. Further, if we're slightly speeding the clocksource
1918 * in the code above, its possible the required corrective factor to
1919 * xtime_nsec could cause it to underflow.
1921 * Now, since we have already accumulated the second and the NTP
1922 * subsystem has been notified via second_overflow(), we need to skip
1925 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1926 tk->tkr_mono.xtime_nsec += (u64)NSEC_PER_SEC <<
1929 tk->skip_second_overflow = 1;
1934 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1936 * Helper function that accumulates the nsecs greater than a second
1937 * from the xtime_nsec field to the xtime_secs field.
1938 * It also calls into the NTP code to handle leapsecond processing.
1941 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1943 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1944 unsigned int clock_set = 0;
1946 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1949 tk->tkr_mono.xtime_nsec -= nsecps;
1953 * Skip NTP update if this second was accumulated before,
1954 * i.e. xtime_nsec underflowed in timekeeping_adjust()
1956 if (unlikely(tk->skip_second_overflow)) {
1957 tk->skip_second_overflow = 0;
1961 /* Figure out if its a leap sec and apply if needed */
1962 leap = second_overflow(tk->xtime_sec);
1963 if (unlikely(leap)) {
1964 struct timespec64 ts;
1966 tk->xtime_sec += leap;
1970 tk_set_wall_to_mono(tk,
1971 timespec64_sub(tk->wall_to_monotonic, ts));
1973 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1975 clock_set = TK_CLOCK_WAS_SET;
1982 * logarithmic_accumulation - shifted accumulation of cycles
1984 * This functions accumulates a shifted interval of cycles into
1985 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1988 * Returns the unconsumed cycles.
1990 static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
1991 u32 shift, unsigned int *clock_set)
1993 u64 interval = tk->cycle_interval << shift;
1996 /* If the offset is smaller than a shifted interval, do nothing */
1997 if (offset < interval)
2000 /* Accumulate one shifted interval */
2002 tk->tkr_mono.cycle_last += interval;
2003 tk->tkr_raw.cycle_last += interval;
2005 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2006 *clock_set |= accumulate_nsecs_to_secs(tk);
2008 /* Accumulate raw time */
2009 tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2010 snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2011 while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2012 tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2016 /* Accumulate error between NTP and clock interval */
2017 tk->ntp_error += tk->ntp_tick << shift;
2018 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2019 (tk->ntp_error_shift + shift);
2025 * update_wall_time - Uses the current clocksource to increment the wall time
2028 void update_wall_time(void)
2030 struct timekeeper *real_tk = &tk_core.timekeeper;
2031 struct timekeeper *tk = &shadow_timekeeper;
2033 int shift = 0, maxshift;
2034 unsigned int clock_set = 0;
2035 unsigned long flags;
2037 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2039 /* Make sure we're fully resumed: */
2040 if (unlikely(timekeeping_suspended))
2043 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2044 offset = real_tk->cycle_interval;
2046 offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2047 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2050 /* Check if there's really nothing to do */
2051 if (offset < real_tk->cycle_interval)
2054 /* Do some additional sanity checking */
2055 timekeeping_check_update(tk, offset);
2058 * With NO_HZ we may have to accumulate many cycle_intervals
2059 * (think "ticks") worth of time at once. To do this efficiently,
2060 * we calculate the largest doubling multiple of cycle_intervals
2061 * that is smaller than the offset. We then accumulate that
2062 * chunk in one go, and then try to consume the next smaller
2065 shift = ilog2(offset) - ilog2(tk->cycle_interval);
2066 shift = max(0, shift);
2067 /* Bound shift to one less than what overflows tick_length */
2068 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2069 shift = min(shift, maxshift);
2070 while (offset >= tk->cycle_interval) {
2071 offset = logarithmic_accumulation(tk, offset, shift,
2073 if (offset < tk->cycle_interval<<shift)
2077 /* Adjust the multiplier to correct NTP error */
2078 timekeeping_adjust(tk, offset);
2081 * Finally, make sure that after the rounding
2082 * xtime_nsec isn't larger than NSEC_PER_SEC
2084 clock_set |= accumulate_nsecs_to_secs(tk);
2086 write_seqcount_begin(&tk_core.seq);
2088 * Update the real timekeeper.
2090 * We could avoid this memcpy by switching pointers, but that
2091 * requires changes to all other timekeeper usage sites as
2092 * well, i.e. move the timekeeper pointer getter into the
2093 * spinlocked/seqcount protected sections. And we trade this
2094 * memcpy under the tk_core.seq against one before we start
2097 timekeeping_update(tk, clock_set);
2098 memcpy(real_tk, tk, sizeof(*tk));
2099 /* The memcpy must come last. Do not put anything here! */
2100 write_seqcount_end(&tk_core.seq);
2102 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2104 /* Have to call _delayed version, since in irq context*/
2105 clock_was_set_delayed();
2109 * getboottime64 - Return the real time of system boot.
2110 * @ts: pointer to the timespec64 to be set
2112 * Returns the wall-time of boot in a timespec64.
2114 * This is based on the wall_to_monotonic offset and the total suspend
2115 * time. Calls to settimeofday will affect the value returned (which
2116 * basically means that however wrong your real time clock is at boot time,
2117 * you get the right time here).
2119 void getboottime64(struct timespec64 *ts)
2121 struct timekeeper *tk = &tk_core.timekeeper;
2122 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2124 *ts = ktime_to_timespec64(t);
2126 EXPORT_SYMBOL_GPL(getboottime64);
2128 unsigned long get_seconds(void)
2130 struct timekeeper *tk = &tk_core.timekeeper;
2132 return tk->xtime_sec;
2134 EXPORT_SYMBOL(get_seconds);
2136 struct timespec64 current_kernel_time64(void)
2138 struct timekeeper *tk = &tk_core.timekeeper;
2139 struct timespec64 now;
2143 seq = read_seqcount_begin(&tk_core.seq);
2146 } while (read_seqcount_retry(&tk_core.seq, seq));
2150 EXPORT_SYMBOL(current_kernel_time64);
2152 struct timespec64 get_monotonic_coarse64(void)
2154 struct timekeeper *tk = &tk_core.timekeeper;
2155 struct timespec64 now, mono;
2159 seq = read_seqcount_begin(&tk_core.seq);
2162 mono = tk->wall_to_monotonic;
2163 } while (read_seqcount_retry(&tk_core.seq, seq));
2165 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
2166 now.tv_nsec + mono.tv_nsec);
2170 EXPORT_SYMBOL(get_monotonic_coarse64);
2173 * Must hold jiffies_lock
2175 void do_timer(unsigned long ticks)
2177 jiffies_64 += ticks;
2178 calc_global_load(ticks);
2182 * ktime_get_update_offsets_now - hrtimer helper
2183 * @cwsseq: pointer to check and store the clock was set sequence number
2184 * @offs_real: pointer to storage for monotonic -> realtime offset
2185 * @offs_boot: pointer to storage for monotonic -> boottime offset
2186 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2188 * Returns current monotonic time and updates the offsets if the
2189 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2192 * Called from hrtimer_interrupt() or retrigger_next_event()
2194 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2195 ktime_t *offs_boot, ktime_t *offs_tai)
2197 struct timekeeper *tk = &tk_core.timekeeper;
2203 seq = read_seqcount_begin(&tk_core.seq);
2205 base = tk->tkr_mono.base;
2206 nsecs = timekeeping_get_ns(&tk->tkr_mono);
2207 base = ktime_add_ns(base, nsecs);
2209 if (*cwsseq != tk->clock_was_set_seq) {
2210 *cwsseq = tk->clock_was_set_seq;
2211 *offs_real = tk->offs_real;
2212 *offs_boot = tk->offs_boot;
2213 *offs_tai = tk->offs_tai;
2216 /* Handle leapsecond insertion adjustments */
2217 if (unlikely(base >= tk->next_leap_ktime))
2218 *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2220 } while (read_seqcount_retry(&tk_core.seq, seq));
2226 * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
2228 static int timekeeping_validate_timex(struct timex *txc)
2230 if (txc->modes & ADJ_ADJTIME) {
2231 /* singleshot must not be used with any other mode bits */
2232 if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
2234 if (!(txc->modes & ADJ_OFFSET_READONLY) &&
2235 !capable(CAP_SYS_TIME))
2238 /* In order to modify anything, you gotta be super-user! */
2239 if (txc->modes && !capable(CAP_SYS_TIME))
2242 * if the quartz is off by more than 10% then
2243 * something is VERY wrong!
2245 if (txc->modes & ADJ_TICK &&
2246 (txc->tick < 900000/USER_HZ ||
2247 txc->tick > 1100000/USER_HZ))
2251 if (txc->modes & ADJ_SETOFFSET) {
2252 /* In order to inject time, you gotta be super-user! */
2253 if (!capable(CAP_SYS_TIME))
2257 * Validate if a timespec/timeval used to inject a time
2258 * offset is valid. Offsets can be postive or negative, so
2259 * we don't check tv_sec. The value of the timeval/timespec
2260 * is the sum of its fields,but *NOTE*:
2261 * The field tv_usec/tv_nsec must always be non-negative and
2262 * we can't have more nanoseconds/microseconds than a second.
2264 if (txc->time.tv_usec < 0)
2267 if (txc->modes & ADJ_NANO) {
2268 if (txc->time.tv_usec >= NSEC_PER_SEC)
2271 if (txc->time.tv_usec >= USEC_PER_SEC)
2277 * Check for potential multiplication overflows that can
2278 * only happen on 64-bit systems:
2280 if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
2281 if (LLONG_MIN / PPM_SCALE > txc->freq)
2283 if (LLONG_MAX / PPM_SCALE < txc->freq)
2292 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2294 int do_adjtimex(struct timex *txc)
2296 struct timekeeper *tk = &tk_core.timekeeper;
2297 unsigned long flags;
2298 struct timespec64 ts;
2302 /* Validate the data before disabling interrupts */
2303 ret = timekeeping_validate_timex(txc);
2307 if (txc->modes & ADJ_SETOFFSET) {
2308 struct timespec64 delta;
2309 delta.tv_sec = txc->time.tv_sec;
2310 delta.tv_nsec = txc->time.tv_usec;
2311 if (!(txc->modes & ADJ_NANO))
2312 delta.tv_nsec *= 1000;
2313 ret = timekeeping_inject_offset(&delta);
2318 getnstimeofday64(&ts);
2320 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2321 write_seqcount_begin(&tk_core.seq);
2323 orig_tai = tai = tk->tai_offset;
2324 ret = __do_adjtimex(txc, &ts, &tai);
2326 if (tai != orig_tai) {
2327 __timekeeping_set_tai_offset(tk, tai);
2328 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2330 tk_update_leap_state(tk);
2332 write_seqcount_end(&tk_core.seq);
2333 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2335 if (tai != orig_tai)
2338 ntp_notify_cmos_timer();
2343 #ifdef CONFIG_NTP_PPS
2345 * hardpps() - Accessor function to NTP __hardpps function
2347 void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2349 unsigned long flags;
2351 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2352 write_seqcount_begin(&tk_core.seq);
2354 __hardpps(phase_ts, raw_ts);
2356 write_seqcount_end(&tk_core.seq);
2357 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2359 EXPORT_SYMBOL(hardpps);
2360 #endif /* CONFIG_NTP_PPS */
2363 * xtime_update() - advances the timekeeping infrastructure
2364 * @ticks: number of ticks, that have elapsed since the last call.
2366 * Must be called with interrupts disabled.
2368 void xtime_update(unsigned long ticks)
2370 write_seqlock(&jiffies_lock);
2372 write_sequnlock(&jiffies_lock);