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 /* Update both bases so mono and raw stay coupled. */
142 tk->tkr_mono.base += delta;
143 tk->tkr_raw.base += delta;
145 /* Accumulate time spent in suspend */
146 tk->time_suspended += delta;
150 * tk_clock_read - atomic clocksource read() helper
152 * This helper is necessary to use in the read paths because, while the
153 * seqlock ensures we don't return a bad value while structures are updated,
154 * it doesn't protect from potential crashes. There is the possibility that
155 * the tkr's clocksource may change between the read reference, and the
156 * clock reference passed to the read function. This can cause crashes if
157 * the wrong clocksource is passed to the wrong read function.
158 * This isn't necessary to use when holding the timekeeper_lock or doing
159 * a read of the fast-timekeeper tkrs (which is protected by its own locking
162 static inline u64 tk_clock_read(struct tk_read_base *tkr)
164 struct clocksource *clock = READ_ONCE(tkr->clock);
166 return clock->read(clock);
169 #ifdef CONFIG_DEBUG_TIMEKEEPING
170 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
172 static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
175 u64 max_cycles = tk->tkr_mono.clock->max_cycles;
176 const char *name = tk->tkr_mono.clock->name;
178 if (offset > max_cycles) {
179 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
180 offset, name, max_cycles);
181 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
183 if (offset > (max_cycles >> 1)) {
184 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
185 offset, name, max_cycles >> 1);
186 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
190 if (tk->underflow_seen) {
191 if (jiffies - tk->last_warning > WARNING_FREQ) {
192 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
193 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
194 printk_deferred(" Your kernel is probably still fine.\n");
195 tk->last_warning = jiffies;
197 tk->underflow_seen = 0;
200 if (tk->overflow_seen) {
201 if (jiffies - tk->last_warning > WARNING_FREQ) {
202 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
203 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
204 printk_deferred(" Your kernel is probably still fine.\n");
205 tk->last_warning = jiffies;
207 tk->overflow_seen = 0;
211 static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
213 struct timekeeper *tk = &tk_core.timekeeper;
214 u64 now, last, mask, max, delta;
218 * Since we're called holding a seqlock, the data may shift
219 * under us while we're doing the calculation. This can cause
220 * false positives, since we'd note a problem but throw the
221 * results away. So nest another seqlock here to atomically
222 * grab the points we are checking with.
225 seq = read_seqcount_begin(&tk_core.seq);
226 now = tk_clock_read(tkr);
227 last = tkr->cycle_last;
229 max = tkr->clock->max_cycles;
230 } while (read_seqcount_retry(&tk_core.seq, seq));
232 delta = clocksource_delta(now, last, mask);
235 * Try to catch underflows by checking if we are seeing small
236 * mask-relative negative values.
238 if (unlikely((~delta & mask) < (mask >> 3))) {
239 tk->underflow_seen = 1;
243 /* Cap delta value to the max_cycles values to avoid mult overflows */
244 if (unlikely(delta > max)) {
245 tk->overflow_seen = 1;
246 delta = tkr->clock->max_cycles;
252 static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
255 static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
257 u64 cycle_now, delta;
259 /* read clocksource */
260 cycle_now = tk_clock_read(tkr);
262 /* calculate the delta since the last update_wall_time */
263 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
270 * tk_setup_internals - Set up internals to use clocksource clock.
272 * @tk: The target timekeeper to setup.
273 * @clock: Pointer to clocksource.
275 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
276 * pair and interval request.
278 * Unless you're the timekeeping code, you should not be using this!
280 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
283 u64 tmp, ntpinterval;
284 struct clocksource *old_clock;
286 ++tk->cs_was_changed_seq;
287 old_clock = tk->tkr_mono.clock;
288 tk->tkr_mono.clock = clock;
289 tk->tkr_mono.mask = clock->mask;
290 tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
292 tk->tkr_raw.clock = clock;
293 tk->tkr_raw.mask = clock->mask;
294 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
296 /* Do the ns -> cycle conversion first, using original mult */
297 tmp = NTP_INTERVAL_LENGTH;
298 tmp <<= clock->shift;
300 tmp += clock->mult/2;
301 do_div(tmp, clock->mult);
305 interval = (u64) tmp;
306 tk->cycle_interval = interval;
308 /* Go back from cycles -> shifted ns */
309 tk->xtime_interval = interval * clock->mult;
310 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
311 tk->raw_interval = interval * clock->mult;
313 /* if changing clocks, convert xtime_nsec shift units */
315 int shift_change = clock->shift - old_clock->shift;
316 if (shift_change < 0) {
317 tk->tkr_mono.xtime_nsec >>= -shift_change;
318 tk->tkr_raw.xtime_nsec >>= -shift_change;
320 tk->tkr_mono.xtime_nsec <<= shift_change;
321 tk->tkr_raw.xtime_nsec <<= shift_change;
325 tk->tkr_mono.shift = clock->shift;
326 tk->tkr_raw.shift = clock->shift;
329 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
330 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
333 * The timekeeper keeps its own mult values for the currently
334 * active clocksource. These value will be adjusted via NTP
335 * to counteract clock drifting.
337 tk->tkr_mono.mult = clock->mult;
338 tk->tkr_raw.mult = clock->mult;
339 tk->ntp_err_mult = 0;
340 tk->skip_second_overflow = 0;
343 /* Timekeeper helper functions. */
345 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
346 static u32 default_arch_gettimeoffset(void) { return 0; }
347 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
349 static inline u32 arch_gettimeoffset(void) { return 0; }
352 static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr, u64 delta)
356 nsec = delta * tkr->mult + tkr->xtime_nsec;
359 /* If arch requires, add in get_arch_timeoffset() */
360 return nsec + arch_gettimeoffset();
363 static inline u64 timekeeping_get_ns(struct tk_read_base *tkr)
367 delta = timekeeping_get_delta(tkr);
368 return timekeeping_delta_to_ns(tkr, delta);
371 static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr, u64 cycles)
375 /* calculate the delta since the last update_wall_time */
376 delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
377 return timekeeping_delta_to_ns(tkr, delta);
381 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
382 * @tkr: Timekeeping readout base from which we take the update
384 * We want to use this from any context including NMI and tracing /
385 * instrumenting the timekeeping code itself.
387 * Employ the latch technique; see @raw_write_seqcount_latch.
389 * So if a NMI hits the update of base[0] then it will use base[1]
390 * which is still consistent. In the worst case this can result is a
391 * slightly wrong timestamp (a few nanoseconds). See
392 * @ktime_get_mono_fast_ns.
394 static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
396 struct tk_read_base *base = tkf->base;
398 /* Force readers off to base[1] */
399 raw_write_seqcount_latch(&tkf->seq);
402 memcpy(base, tkr, sizeof(*base));
404 /* Force readers back to base[0] */
405 raw_write_seqcount_latch(&tkf->seq);
408 memcpy(base + 1, base, sizeof(*base));
412 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
414 * This timestamp is not guaranteed to be monotonic across an update.
415 * The timestamp is calculated by:
417 * now = base_mono + clock_delta * slope
419 * So if the update lowers the slope, readers who are forced to the
420 * not yet updated second array are still using the old steeper slope.
429 * |12345678---> reader order
435 * So reader 6 will observe time going backwards versus reader 5.
437 * While other CPUs are likely to be able observe that, the only way
438 * for a CPU local observation is when an NMI hits in the middle of
439 * the update. Timestamps taken from that NMI context might be ahead
440 * of the following timestamps. Callers need to be aware of that and
443 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
445 struct tk_read_base *tkr;
450 seq = raw_read_seqcount_latch(&tkf->seq);
451 tkr = tkf->base + (seq & 0x01);
452 now = ktime_to_ns(tkr->base);
454 now += timekeeping_delta_to_ns(tkr,
459 } while (read_seqcount_retry(&tkf->seq, seq));
464 u64 ktime_get_mono_fast_ns(void)
466 return __ktime_get_fast_ns(&tk_fast_mono);
468 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
470 u64 ktime_get_raw_fast_ns(void)
472 return __ktime_get_fast_ns(&tk_fast_raw);
474 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
477 * See comment for __ktime_get_fast_ns() vs. timestamp ordering
479 static __always_inline u64 __ktime_get_real_fast_ns(struct tk_fast *tkf)
481 struct tk_read_base *tkr;
486 seq = raw_read_seqcount_latch(&tkf->seq);
487 tkr = tkf->base + (seq & 0x01);
488 now = ktime_to_ns(tkr->base_real);
490 now += timekeeping_delta_to_ns(tkr,
495 } while (read_seqcount_retry(&tkf->seq, seq));
501 * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime.
503 u64 ktime_get_real_fast_ns(void)
505 return __ktime_get_real_fast_ns(&tk_fast_mono);
507 EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
510 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
511 * @tk: Timekeeper to snapshot.
513 * It generally is unsafe to access the clocksource after timekeeping has been
514 * suspended, so take a snapshot of the readout base of @tk and use it as the
515 * fast timekeeper's readout base while suspended. It will return the same
516 * number of cycles every time until timekeeping is resumed at which time the
517 * proper readout base for the fast timekeeper will be restored automatically.
519 static void halt_fast_timekeeper(struct timekeeper *tk)
521 static struct tk_read_base tkr_dummy;
522 struct tk_read_base *tkr = &tk->tkr_mono;
524 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
525 cycles_at_suspend = tk_clock_read(tkr);
526 tkr_dummy.clock = &dummy_clock;
527 tkr_dummy.base_real = tkr->base + tk->offs_real;
528 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
531 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
532 tkr_dummy.clock = &dummy_clock;
533 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
536 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
538 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
540 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
544 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
546 int pvclock_gtod_register_notifier(struct notifier_block *nb)
548 struct timekeeper *tk = &tk_core.timekeeper;
552 raw_spin_lock_irqsave(&timekeeper_lock, flags);
553 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
554 update_pvclock_gtod(tk, true);
555 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
559 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
562 * pvclock_gtod_unregister_notifier - unregister a pvclock
563 * timedata update listener
565 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
570 raw_spin_lock_irqsave(&timekeeper_lock, flags);
571 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
572 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
576 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
579 * tk_update_leap_state - helper to update the next_leap_ktime
581 static inline void tk_update_leap_state(struct timekeeper *tk)
583 tk->next_leap_ktime = ntp_get_next_leap();
584 if (tk->next_leap_ktime != KTIME_MAX)
585 /* Convert to monotonic time */
586 tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
590 * Update the ktime_t based scalar nsec members of the timekeeper
592 static inline void tk_update_ktime_data(struct timekeeper *tk)
598 * The xtime based monotonic readout is:
599 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
600 * The ktime based monotonic readout is:
601 * nsec = base_mono + now();
602 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
604 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
605 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
606 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
609 * The sum of the nanoseconds portions of xtime and
610 * wall_to_monotonic can be greater/equal one second. Take
611 * this into account before updating tk->ktime_sec.
613 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
614 if (nsec >= NSEC_PER_SEC)
616 tk->ktime_sec = seconds;
618 /* Update the monotonic raw base */
619 tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC);
622 /* must hold timekeeper_lock */
623 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
625 if (action & TK_CLEAR_NTP) {
630 tk_update_leap_state(tk);
631 tk_update_ktime_data(tk);
634 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
636 tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real;
637 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
638 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
640 if (action & TK_CLOCK_WAS_SET)
641 tk->clock_was_set_seq++;
643 * The mirroring of the data to the shadow-timekeeper needs
644 * to happen last here to ensure we don't over-write the
645 * timekeeper structure on the next update with stale data
647 if (action & TK_MIRROR)
648 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
649 sizeof(tk_core.timekeeper));
653 * timekeeping_forward_now - update clock to the current time
655 * Forward the current clock to update its state since the last call to
656 * update_wall_time(). This is useful before significant clock changes,
657 * as it avoids having to deal with this time offset explicitly.
659 static void timekeeping_forward_now(struct timekeeper *tk)
661 u64 cycle_now, delta;
663 cycle_now = tk_clock_read(&tk->tkr_mono);
664 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
665 tk->tkr_mono.cycle_last = cycle_now;
666 tk->tkr_raw.cycle_last = cycle_now;
668 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
670 /* If arch requires, add in get_arch_timeoffset() */
671 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
674 tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;
676 /* If arch requires, add in get_arch_timeoffset() */
677 tk->tkr_raw.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_raw.shift;
679 tk_normalize_xtime(tk);
683 * __getnstimeofday64 - Returns the time of day in a timespec64.
684 * @ts: pointer to the timespec to be set
686 * Updates the time of day in the timespec.
687 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
689 int __getnstimeofday64(struct timespec64 *ts)
691 struct timekeeper *tk = &tk_core.timekeeper;
696 seq = read_seqcount_begin(&tk_core.seq);
698 ts->tv_sec = tk->xtime_sec;
699 nsecs = timekeeping_get_ns(&tk->tkr_mono);
701 } while (read_seqcount_retry(&tk_core.seq, seq));
704 timespec64_add_ns(ts, nsecs);
707 * Do not bail out early, in case there were callers still using
708 * the value, even in the face of the WARN_ON.
710 if (unlikely(timekeeping_suspended))
714 EXPORT_SYMBOL(__getnstimeofday64);
717 * getnstimeofday64 - Returns the time of day in a timespec64.
718 * @ts: pointer to the timespec64 to be set
720 * Returns the time of day in a timespec64 (WARN if suspended).
722 void getnstimeofday64(struct timespec64 *ts)
724 WARN_ON(__getnstimeofday64(ts));
726 EXPORT_SYMBOL(getnstimeofday64);
728 ktime_t ktime_get(void)
730 struct timekeeper *tk = &tk_core.timekeeper;
735 WARN_ON(timekeeping_suspended);
738 seq = read_seqcount_begin(&tk_core.seq);
739 base = tk->tkr_mono.base;
740 nsecs = timekeeping_get_ns(&tk->tkr_mono);
742 } while (read_seqcount_retry(&tk_core.seq, seq));
744 return ktime_add_ns(base, nsecs);
746 EXPORT_SYMBOL_GPL(ktime_get);
748 u32 ktime_get_resolution_ns(void)
750 struct timekeeper *tk = &tk_core.timekeeper;
754 WARN_ON(timekeeping_suspended);
757 seq = read_seqcount_begin(&tk_core.seq);
758 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
759 } while (read_seqcount_retry(&tk_core.seq, seq));
763 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
765 static ktime_t *offsets[TK_OFFS_MAX] = {
766 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
767 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
770 ktime_t ktime_get_with_offset(enum tk_offsets offs)
772 struct timekeeper *tk = &tk_core.timekeeper;
774 ktime_t base, *offset = offsets[offs];
777 WARN_ON(timekeeping_suspended);
780 seq = read_seqcount_begin(&tk_core.seq);
781 base = ktime_add(tk->tkr_mono.base, *offset);
782 nsecs = timekeeping_get_ns(&tk->tkr_mono);
784 } while (read_seqcount_retry(&tk_core.seq, seq));
786 return ktime_add_ns(base, nsecs);
789 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
792 * ktime_mono_to_any() - convert mononotic time to any other time
793 * @tmono: time to convert.
794 * @offs: which offset to use
796 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
798 ktime_t *offset = offsets[offs];
803 seq = read_seqcount_begin(&tk_core.seq);
804 tconv = ktime_add(tmono, *offset);
805 } while (read_seqcount_retry(&tk_core.seq, seq));
809 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
812 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
814 ktime_t ktime_get_raw(void)
816 struct timekeeper *tk = &tk_core.timekeeper;
822 seq = read_seqcount_begin(&tk_core.seq);
823 base = tk->tkr_raw.base;
824 nsecs = timekeeping_get_ns(&tk->tkr_raw);
826 } while (read_seqcount_retry(&tk_core.seq, seq));
828 return ktime_add_ns(base, nsecs);
830 EXPORT_SYMBOL_GPL(ktime_get_raw);
833 * ktime_get_ts64 - get the monotonic clock in timespec64 format
834 * @ts: pointer to timespec variable
836 * The function calculates the monotonic clock from the realtime
837 * clock and the wall_to_monotonic offset and stores the result
838 * in normalized timespec64 format in the variable pointed to by @ts.
840 void ktime_get_ts64(struct timespec64 *ts)
842 struct timekeeper *tk = &tk_core.timekeeper;
843 struct timespec64 tomono;
847 WARN_ON(timekeeping_suspended);
850 seq = read_seqcount_begin(&tk_core.seq);
851 ts->tv_sec = tk->xtime_sec;
852 nsec = timekeeping_get_ns(&tk->tkr_mono);
853 tomono = tk->wall_to_monotonic;
855 } while (read_seqcount_retry(&tk_core.seq, seq));
857 ts->tv_sec += tomono.tv_sec;
859 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
861 EXPORT_SYMBOL_GPL(ktime_get_ts64);
864 * ktime_get_active_ts64 - Get the active non-suspended monotonic clock
865 * @ts: pointer to timespec variable
867 * The function calculates the monotonic clock from the realtime clock and
868 * the wall_to_monotonic offset, subtracts the accumulated suspend time and
869 * stores the result in normalized timespec64 format in the variable
872 void ktime_get_active_ts64(struct timespec64 *ts)
874 struct timekeeper *tk = &tk_core.timekeeper;
875 struct timespec64 tomono, tsusp;
879 WARN_ON(timekeeping_suspended);
882 seq = read_seqcount_begin(&tk_core.seq);
883 ts->tv_sec = tk->xtime_sec;
884 nsec = timekeeping_get_ns(&tk->tkr_mono);
885 tomono = tk->wall_to_monotonic;
886 nssusp = tk->time_suspended;
887 } while (read_seqcount_retry(&tk_core.seq, seq));
889 ts->tv_sec += tomono.tv_sec;
891 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
892 tsusp = ns_to_timespec64(nssusp);
893 *ts = timespec64_sub(*ts, tsusp);
897 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
899 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
900 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
901 * works on both 32 and 64 bit systems. On 32 bit systems the readout
902 * covers ~136 years of uptime which should be enough to prevent
903 * premature wrap arounds.
905 time64_t ktime_get_seconds(void)
907 struct timekeeper *tk = &tk_core.timekeeper;
909 WARN_ON(timekeeping_suspended);
910 return tk->ktime_sec;
912 EXPORT_SYMBOL_GPL(ktime_get_seconds);
915 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
917 * Returns the wall clock seconds since 1970. This replaces the
918 * get_seconds() interface which is not y2038 safe on 32bit systems.
920 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
921 * 32bit systems the access must be protected with the sequence
922 * counter to provide "atomic" access to the 64bit tk->xtime_sec
925 time64_t ktime_get_real_seconds(void)
927 struct timekeeper *tk = &tk_core.timekeeper;
931 if (IS_ENABLED(CONFIG_64BIT))
932 return tk->xtime_sec;
935 seq = read_seqcount_begin(&tk_core.seq);
936 seconds = tk->xtime_sec;
938 } while (read_seqcount_retry(&tk_core.seq, seq));
942 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
945 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
946 * but without the sequence counter protect. This internal function
947 * is called just when timekeeping lock is already held.
949 time64_t __ktime_get_real_seconds(void)
951 struct timekeeper *tk = &tk_core.timekeeper;
953 return tk->xtime_sec;
957 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
958 * @systime_snapshot: pointer to struct receiving the system time snapshot
960 void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
962 struct timekeeper *tk = &tk_core.timekeeper;
970 WARN_ON_ONCE(timekeeping_suspended);
973 seq = read_seqcount_begin(&tk_core.seq);
974 now = tk_clock_read(&tk->tkr_mono);
975 systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
976 systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
977 base_real = ktime_add(tk->tkr_mono.base,
978 tk_core.timekeeper.offs_real);
979 base_raw = tk->tkr_raw.base;
980 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
981 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
982 } while (read_seqcount_retry(&tk_core.seq, seq));
984 systime_snapshot->cycles = now;
985 systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
986 systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
988 EXPORT_SYMBOL_GPL(ktime_get_snapshot);
990 /* Scale base by mult/div checking for overflow */
991 static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
995 tmp = div64_u64_rem(*base, div, &rem);
997 if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
998 ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
1009 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
1010 * @history: Snapshot representing start of history
1011 * @partial_history_cycles: Cycle offset into history (fractional part)
1012 * @total_history_cycles: Total history length in cycles
1013 * @discontinuity: True indicates clock was set on history period
1014 * @ts: Cross timestamp that should be adjusted using
1015 * partial/total ratio
1017 * Helper function used by get_device_system_crosststamp() to correct the
1018 * crosstimestamp corresponding to the start of the current interval to the
1019 * system counter value (timestamp point) provided by the driver. The
1020 * total_history_* quantities are the total history starting at the provided
1021 * reference point and ending at the start of the current interval. The cycle
1022 * count between the driver timestamp point and the start of the current
1023 * interval is partial_history_cycles.
1025 static int adjust_historical_crosststamp(struct system_time_snapshot *history,
1026 u64 partial_history_cycles,
1027 u64 total_history_cycles,
1029 struct system_device_crosststamp *ts)
1031 struct timekeeper *tk = &tk_core.timekeeper;
1032 u64 corr_raw, corr_real;
1033 bool interp_forward;
1036 if (total_history_cycles == 0 || partial_history_cycles == 0)
1039 /* Interpolate shortest distance from beginning or end of history */
1040 interp_forward = partial_history_cycles > total_history_cycles / 2;
1041 partial_history_cycles = interp_forward ?
1042 total_history_cycles - partial_history_cycles :
1043 partial_history_cycles;
1046 * Scale the monotonic raw time delta by:
1047 * partial_history_cycles / total_history_cycles
1049 corr_raw = (u64)ktime_to_ns(
1050 ktime_sub(ts->sys_monoraw, history->raw));
1051 ret = scale64_check_overflow(partial_history_cycles,
1052 total_history_cycles, &corr_raw);
1057 * If there is a discontinuity in the history, scale monotonic raw
1059 * mult(real)/mult(raw) yielding the realtime correction
1060 * Otherwise, calculate the realtime correction similar to monotonic
1063 if (discontinuity) {
1064 corr_real = mul_u64_u32_div
1065 (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1067 corr_real = (u64)ktime_to_ns(
1068 ktime_sub(ts->sys_realtime, history->real));
1069 ret = scale64_check_overflow(partial_history_cycles,
1070 total_history_cycles, &corr_real);
1075 /* Fixup monotonic raw and real time time values */
1076 if (interp_forward) {
1077 ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1078 ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1080 ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1081 ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1088 * cycle_between - true if test occurs chronologically between before and after
1090 static bool cycle_between(u64 before, u64 test, u64 after)
1092 if (test > before && test < after)
1094 if (test < before && before > after)
1100 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1101 * @get_time_fn: Callback to get simultaneous device time and
1102 * system counter from the device driver
1103 * @ctx: Context passed to get_time_fn()
1104 * @history_begin: Historical reference point used to interpolate system
1105 * time when counter provided by the driver is before the current interval
1106 * @xtstamp: Receives simultaneously captured system and device time
1108 * Reads a timestamp from a device and correlates it to system time
1110 int get_device_system_crosststamp(int (*get_time_fn)
1111 (ktime_t *device_time,
1112 struct system_counterval_t *sys_counterval,
1115 struct system_time_snapshot *history_begin,
1116 struct system_device_crosststamp *xtstamp)
1118 struct system_counterval_t system_counterval;
1119 struct timekeeper *tk = &tk_core.timekeeper;
1120 u64 cycles, now, interval_start;
1121 unsigned int clock_was_set_seq = 0;
1122 ktime_t base_real, base_raw;
1123 u64 nsec_real, nsec_raw;
1124 u8 cs_was_changed_seq;
1130 seq = read_seqcount_begin(&tk_core.seq);
1132 * Try to synchronously capture device time and a system
1133 * counter value calling back into the device driver
1135 ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1140 * Verify that the clocksource associated with the captured
1141 * system counter value is the same as the currently installed
1142 * timekeeper clocksource
1144 if (tk->tkr_mono.clock != system_counterval.cs)
1146 cycles = system_counterval.cycles;
1149 * Check whether the system counter value provided by the
1150 * device driver is on the current timekeeping interval.
1152 now = tk_clock_read(&tk->tkr_mono);
1153 interval_start = tk->tkr_mono.cycle_last;
1154 if (!cycle_between(interval_start, cycles, now)) {
1155 clock_was_set_seq = tk->clock_was_set_seq;
1156 cs_was_changed_seq = tk->cs_was_changed_seq;
1157 cycles = interval_start;
1163 base_real = ktime_add(tk->tkr_mono.base,
1164 tk_core.timekeeper.offs_real);
1165 base_raw = tk->tkr_raw.base;
1167 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1168 system_counterval.cycles);
1169 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1170 system_counterval.cycles);
1171 } while (read_seqcount_retry(&tk_core.seq, seq));
1173 xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1174 xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1177 * Interpolate if necessary, adjusting back from the start of the
1181 u64 partial_history_cycles, total_history_cycles;
1185 * Check that the counter value occurs after the provided
1186 * history reference and that the history doesn't cross a
1187 * clocksource change
1189 if (!history_begin ||
1190 !cycle_between(history_begin->cycles,
1191 system_counterval.cycles, cycles) ||
1192 history_begin->cs_was_changed_seq != cs_was_changed_seq)
1194 partial_history_cycles = cycles - system_counterval.cycles;
1195 total_history_cycles = cycles - history_begin->cycles;
1197 history_begin->clock_was_set_seq != clock_was_set_seq;
1199 ret = adjust_historical_crosststamp(history_begin,
1200 partial_history_cycles,
1201 total_history_cycles,
1202 discontinuity, xtstamp);
1209 EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1212 * do_gettimeofday - Returns the time of day in a timeval
1213 * @tv: pointer to the timeval to be set
1215 * NOTE: Users should be converted to using getnstimeofday()
1217 void do_gettimeofday(struct timeval *tv)
1219 struct timespec64 now;
1221 getnstimeofday64(&now);
1222 tv->tv_sec = now.tv_sec;
1223 tv->tv_usec = now.tv_nsec/1000;
1225 EXPORT_SYMBOL(do_gettimeofday);
1228 * do_settimeofday64 - Sets the time of day.
1229 * @ts: pointer to the timespec64 variable containing the new time
1231 * Sets the time of day to the new time and update NTP and notify hrtimers
1233 int do_settimeofday64(const struct timespec64 *ts)
1235 struct timekeeper *tk = &tk_core.timekeeper;
1236 struct timespec64 ts_delta, xt;
1237 unsigned long flags;
1240 if (!timespec64_valid_strict(ts))
1243 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1244 write_seqcount_begin(&tk_core.seq);
1246 timekeeping_forward_now(tk);
1249 ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
1250 ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
1252 if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1257 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1259 tk_set_xtime(tk, ts);
1261 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1263 write_seqcount_end(&tk_core.seq);
1264 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1266 /* signal hrtimers about time change */
1271 EXPORT_SYMBOL(do_settimeofday64);
1274 * timekeeping_inject_offset - Adds or subtracts from the current time.
1275 * @tv: pointer to the timespec variable containing the offset
1277 * Adds or subtracts an offset value from the current time.
1279 static int timekeeping_inject_offset(struct timespec64 *ts)
1281 struct timekeeper *tk = &tk_core.timekeeper;
1282 unsigned long flags;
1283 struct timespec64 tmp;
1286 if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
1289 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1290 write_seqcount_begin(&tk_core.seq);
1292 timekeeping_forward_now(tk);
1294 /* Make sure the proposed value is valid */
1295 tmp = timespec64_add(tk_xtime(tk), *ts);
1296 if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
1297 !timespec64_valid_strict(&tmp)) {
1302 tk_xtime_add(tk, ts);
1303 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *ts));
1305 error: /* even if we error out, we forwarded the time, so call update */
1306 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1308 write_seqcount_end(&tk_core.seq);
1309 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1311 /* signal hrtimers about time change */
1318 * Indicates if there is an offset between the system clock and the hardware
1319 * clock/persistent clock/rtc.
1321 int persistent_clock_is_local;
1324 * Adjust the time obtained from the CMOS to be UTC time instead of
1327 * This is ugly, but preferable to the alternatives. Otherwise we
1328 * would either need to write a program to do it in /etc/rc (and risk
1329 * confusion if the program gets run more than once; it would also be
1330 * hard to make the program warp the clock precisely n hours) or
1331 * compile in the timezone information into the kernel. Bad, bad....
1335 * The best thing to do is to keep the CMOS clock in universal time (UTC)
1336 * as real UNIX machines always do it. This avoids all headaches about
1337 * daylight saving times and warping kernel clocks.
1339 void timekeeping_warp_clock(void)
1341 if (sys_tz.tz_minuteswest != 0) {
1342 struct timespec64 adjust;
1344 persistent_clock_is_local = 1;
1345 adjust.tv_sec = sys_tz.tz_minuteswest * 60;
1347 timekeeping_inject_offset(&adjust);
1352 * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
1355 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1357 tk->tai_offset = tai_offset;
1358 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1362 * change_clocksource - Swaps clocksources if a new one is available
1364 * Accumulates current time interval and initializes new clocksource
1366 static int change_clocksource(void *data)
1368 struct timekeeper *tk = &tk_core.timekeeper;
1369 struct clocksource *new, *old;
1370 unsigned long flags;
1372 new = (struct clocksource *) data;
1374 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1375 write_seqcount_begin(&tk_core.seq);
1377 timekeeping_forward_now(tk);
1379 * If the cs is in module, get a module reference. Succeeds
1380 * for built-in code (owner == NULL) as well.
1382 if (try_module_get(new->owner)) {
1383 if (!new->enable || new->enable(new) == 0) {
1384 old = tk->tkr_mono.clock;
1385 tk_setup_internals(tk, new);
1388 module_put(old->owner);
1390 module_put(new->owner);
1393 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1395 write_seqcount_end(&tk_core.seq);
1396 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1402 * timekeeping_notify - Install a new clock source
1403 * @clock: pointer to the clock source
1405 * This function is called from clocksource.c after a new, better clock
1406 * source has been registered. The caller holds the clocksource_mutex.
1408 int timekeeping_notify(struct clocksource *clock)
1410 struct timekeeper *tk = &tk_core.timekeeper;
1412 if (tk->tkr_mono.clock == clock)
1414 stop_machine(change_clocksource, clock, NULL);
1415 tick_clock_notify();
1416 return tk->tkr_mono.clock == clock ? 0 : -1;
1420 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1421 * @ts: pointer to the timespec64 to be set
1423 * Returns the raw monotonic time (completely un-modified by ntp)
1425 void getrawmonotonic64(struct timespec64 *ts)
1427 struct timekeeper *tk = &tk_core.timekeeper;
1432 seq = read_seqcount_begin(&tk_core.seq);
1433 ts->tv_sec = tk->raw_sec;
1434 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1436 } while (read_seqcount_retry(&tk_core.seq, seq));
1439 timespec64_add_ns(ts, nsecs);
1441 EXPORT_SYMBOL(getrawmonotonic64);
1445 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1447 int timekeeping_valid_for_hres(void)
1449 struct timekeeper *tk = &tk_core.timekeeper;
1454 seq = read_seqcount_begin(&tk_core.seq);
1456 ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1458 } while (read_seqcount_retry(&tk_core.seq, seq));
1464 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1466 u64 timekeeping_max_deferment(void)
1468 struct timekeeper *tk = &tk_core.timekeeper;
1473 seq = read_seqcount_begin(&tk_core.seq);
1475 ret = tk->tkr_mono.clock->max_idle_ns;
1477 } while (read_seqcount_retry(&tk_core.seq, seq));
1483 * read_persistent_clock - Return time from the persistent clock.
1485 * Weak dummy function for arches that do not yet support it.
1486 * Reads the time from the battery backed persistent clock.
1487 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1489 * XXX - Do be sure to remove it once all arches implement it.
1491 void __weak read_persistent_clock(struct timespec *ts)
1497 void __weak read_persistent_clock64(struct timespec64 *ts64)
1501 read_persistent_clock(&ts);
1502 *ts64 = timespec_to_timespec64(ts);
1506 * read_boot_clock64 - Return time of the system start.
1508 * Weak dummy function for arches that do not yet support it.
1509 * Function to read the exact time the system has been started.
1510 * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported.
1512 * XXX - Do be sure to remove it once all arches implement it.
1514 void __weak read_boot_clock64(struct timespec64 *ts)
1520 /* Flag for if timekeeping_resume() has injected sleeptime */
1521 static bool sleeptime_injected;
1523 /* Flag for if there is a persistent clock on this platform */
1524 static bool persistent_clock_exists;
1527 * timekeeping_init - Initializes the clocksource and common timekeeping values
1529 void __init timekeeping_init(void)
1531 struct timekeeper *tk = &tk_core.timekeeper;
1532 struct clocksource *clock;
1533 unsigned long flags;
1534 struct timespec64 now, boot, tmp;
1536 read_persistent_clock64(&now);
1537 if (!timespec64_valid_strict(&now)) {
1538 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1539 " Check your CMOS/BIOS settings.\n");
1542 } else if (now.tv_sec || now.tv_nsec)
1543 persistent_clock_exists = true;
1545 read_boot_clock64(&boot);
1546 if (!timespec64_valid_strict(&boot)) {
1547 pr_warn("WARNING: Boot clock returned invalid value!\n"
1548 " Check your CMOS/BIOS settings.\n");
1553 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1554 write_seqcount_begin(&tk_core.seq);
1557 clock = clocksource_default_clock();
1559 clock->enable(clock);
1560 tk_setup_internals(tk, clock);
1562 tk_set_xtime(tk, &now);
1564 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1565 boot = tk_xtime(tk);
1567 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1568 tk_set_wall_to_mono(tk, tmp);
1570 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1572 write_seqcount_end(&tk_core.seq);
1573 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1576 /* time in seconds when suspend began for persistent clock */
1577 static struct timespec64 timekeeping_suspend_time;
1580 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1581 * @delta: pointer to a timespec delta value
1583 * Takes a timespec offset measuring a suspend interval and properly
1584 * adds the sleep offset to the timekeeping variables.
1586 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1587 struct timespec64 *delta)
1589 if (!timespec64_valid_strict(delta)) {
1590 printk_deferred(KERN_WARNING
1591 "__timekeeping_inject_sleeptime: Invalid "
1592 "sleep delta value!\n");
1595 tk_xtime_add(tk, delta);
1596 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1597 tk_debug_account_sleep_time(delta);
1600 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1602 * We have three kinds of time sources to use for sleep time
1603 * injection, the preference order is:
1604 * 1) non-stop clocksource
1605 * 2) persistent clock (ie: RTC accessible when irqs are off)
1608 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1609 * If system has neither 1) nor 2), 3) will be used finally.
1612 * If timekeeping has injected sleeptime via either 1) or 2),
1613 * 3) becomes needless, so in this case we don't need to call
1614 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1617 bool timekeeping_rtc_skipresume(void)
1619 return sleeptime_injected;
1623 * 1) can be determined whether to use or not only when doing
1624 * timekeeping_resume() which is invoked after rtc_suspend(),
1625 * so we can't skip rtc_suspend() surely if system has 1).
1627 * But if system has 2), 2) will definitely be used, so in this
1628 * case we don't need to call rtc_suspend(), and this is what
1629 * timekeeping_rtc_skipsuspend() means.
1631 bool timekeeping_rtc_skipsuspend(void)
1633 return persistent_clock_exists;
1637 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1638 * @delta: pointer to a timespec64 delta value
1640 * This hook is for architectures that cannot support read_persistent_clock64
1641 * because their RTC/persistent clock is only accessible when irqs are enabled.
1642 * and also don't have an effective nonstop clocksource.
1644 * This function should only be called by rtc_resume(), and allows
1645 * a suspend offset to be injected into the timekeeping values.
1647 void timekeeping_inject_sleeptime64(struct timespec64 *delta)
1649 struct timekeeper *tk = &tk_core.timekeeper;
1650 unsigned long flags;
1652 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1653 write_seqcount_begin(&tk_core.seq);
1655 timekeeping_forward_now(tk);
1657 __timekeeping_inject_sleeptime(tk, delta);
1659 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1661 write_seqcount_end(&tk_core.seq);
1662 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1664 /* signal hrtimers about time change */
1670 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1672 void timekeeping_resume(void)
1674 struct timekeeper *tk = &tk_core.timekeeper;
1675 struct clocksource *clock = tk->tkr_mono.clock;
1676 unsigned long flags;
1677 struct timespec64 ts_new, ts_delta;
1680 sleeptime_injected = false;
1681 read_persistent_clock64(&ts_new);
1683 clockevents_resume();
1684 clocksource_resume();
1686 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1687 write_seqcount_begin(&tk_core.seq);
1690 * After system resumes, we need to calculate the suspended time and
1691 * compensate it for the OS time. There are 3 sources that could be
1692 * used: Nonstop clocksource during suspend, persistent clock and rtc
1695 * One specific platform may have 1 or 2 or all of them, and the
1696 * preference will be:
1697 * suspend-nonstop clocksource -> persistent clock -> rtc
1698 * The less preferred source will only be tried if there is no better
1699 * usable source. The rtc part is handled separately in rtc core code.
1701 cycle_now = tk_clock_read(&tk->tkr_mono);
1702 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1703 cycle_now > tk->tkr_mono.cycle_last) {
1704 u64 nsec, cyc_delta;
1706 cyc_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
1708 nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift);
1709 ts_delta = ns_to_timespec64(nsec);
1710 sleeptime_injected = true;
1711 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1712 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1713 sleeptime_injected = true;
1716 if (sleeptime_injected)
1717 __timekeeping_inject_sleeptime(tk, &ts_delta);
1719 /* Re-base the last cycle value */
1720 tk->tkr_mono.cycle_last = cycle_now;
1721 tk->tkr_raw.cycle_last = cycle_now;
1724 timekeeping_suspended = 0;
1725 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1726 write_seqcount_end(&tk_core.seq);
1727 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1729 touch_softlockup_watchdog();
1735 int timekeeping_suspend(void)
1737 struct timekeeper *tk = &tk_core.timekeeper;
1738 unsigned long flags;
1739 struct timespec64 delta, delta_delta;
1740 static struct timespec64 old_delta;
1742 read_persistent_clock64(&timekeeping_suspend_time);
1745 * On some systems the persistent_clock can not be detected at
1746 * timekeeping_init by its return value, so if we see a valid
1747 * value returned, update the persistent_clock_exists flag.
1749 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1750 persistent_clock_exists = true;
1752 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1753 write_seqcount_begin(&tk_core.seq);
1754 timekeeping_forward_now(tk);
1755 timekeeping_suspended = 1;
1757 if (persistent_clock_exists) {
1759 * To avoid drift caused by repeated suspend/resumes,
1760 * which each can add ~1 second drift error,
1761 * try to compensate so the difference in system time
1762 * and persistent_clock time stays close to constant.
1764 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1765 delta_delta = timespec64_sub(delta, old_delta);
1766 if (abs(delta_delta.tv_sec) >= 2) {
1768 * if delta_delta is too large, assume time correction
1769 * has occurred and set old_delta to the current delta.
1773 /* Otherwise try to adjust old_system to compensate */
1774 timekeeping_suspend_time =
1775 timespec64_add(timekeeping_suspend_time, delta_delta);
1779 timekeeping_update(tk, TK_MIRROR);
1780 halt_fast_timekeeper(tk);
1781 write_seqcount_end(&tk_core.seq);
1782 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1785 clocksource_suspend();
1786 clockevents_suspend();
1791 /* sysfs resume/suspend bits for timekeeping */
1792 static struct syscore_ops timekeeping_syscore_ops = {
1793 .resume = timekeeping_resume,
1794 .suspend = timekeeping_suspend,
1797 static int __init timekeeping_init_ops(void)
1799 register_syscore_ops(&timekeeping_syscore_ops);
1802 device_initcall(timekeeping_init_ops);
1805 * Apply a multiplier adjustment to the timekeeper
1807 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1811 s64 interval = tk->cycle_interval;
1813 if (mult_adj == 0) {
1815 } else if (mult_adj == -1) {
1816 interval = -interval;
1818 } else if (mult_adj != 1) {
1819 interval *= mult_adj;
1824 * So the following can be confusing.
1826 * To keep things simple, lets assume mult_adj == 1 for now.
1828 * When mult_adj != 1, remember that the interval and offset values
1829 * have been appropriately scaled so the math is the same.
1831 * The basic idea here is that we're increasing the multiplier
1832 * by one, this causes the xtime_interval to be incremented by
1833 * one cycle_interval. This is because:
1834 * xtime_interval = cycle_interval * mult
1835 * So if mult is being incremented by one:
1836 * xtime_interval = cycle_interval * (mult + 1)
1838 * xtime_interval = (cycle_interval * mult) + cycle_interval
1839 * Which can be shortened to:
1840 * xtime_interval += cycle_interval
1842 * So offset stores the non-accumulated cycles. Thus the current
1843 * time (in shifted nanoseconds) is:
1844 * now = (offset * adj) + xtime_nsec
1845 * Now, even though we're adjusting the clock frequency, we have
1846 * to keep time consistent. In other words, we can't jump back
1847 * in time, and we also want to avoid jumping forward in time.
1849 * So given the same offset value, we need the time to be the same
1850 * both before and after the freq adjustment.
1851 * now = (offset * adj_1) + xtime_nsec_1
1852 * now = (offset * adj_2) + xtime_nsec_2
1854 * (offset * adj_1) + xtime_nsec_1 =
1855 * (offset * adj_2) + xtime_nsec_2
1859 * (offset * adj_1) + xtime_nsec_1 =
1860 * (offset * (adj_1+1)) + xtime_nsec_2
1861 * (offset * adj_1) + xtime_nsec_1 =
1862 * (offset * adj_1) + offset + xtime_nsec_2
1863 * Canceling the sides:
1864 * xtime_nsec_1 = offset + xtime_nsec_2
1866 * xtime_nsec_2 = xtime_nsec_1 - offset
1867 * Which simplfies to:
1868 * xtime_nsec -= offset
1870 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1871 /* NTP adjustment caused clocksource mult overflow */
1876 tk->tkr_mono.mult += mult_adj;
1877 tk->xtime_interval += interval;
1878 tk->tkr_mono.xtime_nsec -= offset;
1882 * Adjust the timekeeper's multiplier to the correct frequency
1883 * and also to reduce the accumulated error value.
1885 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1890 * Determine the multiplier from the current NTP tick length.
1891 * Avoid expensive division when the tick length doesn't change.
1893 if (likely(tk->ntp_tick == ntp_tick_length())) {
1894 mult = tk->tkr_mono.mult - tk->ntp_err_mult;
1896 tk->ntp_tick = ntp_tick_length();
1897 mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
1898 tk->xtime_remainder, tk->cycle_interval);
1902 * If the clock is behind the NTP time, increase the multiplier by 1
1903 * to catch up with it. If it's ahead and there was a remainder in the
1904 * tick division, the clock will slow down. Otherwise it will stay
1905 * ahead until the tick length changes to a non-divisible value.
1907 tk->ntp_err_mult = tk->ntp_error > 0 ? 1 : 0;
1908 mult += tk->ntp_err_mult;
1910 timekeeping_apply_adjustment(tk, offset, mult - tk->tkr_mono.mult);
1912 if (unlikely(tk->tkr_mono.clock->maxadj &&
1913 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1914 > tk->tkr_mono.clock->maxadj))) {
1915 printk_once(KERN_WARNING
1916 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1917 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1918 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1922 * It may be possible that when we entered this function, xtime_nsec
1923 * was very small. Further, if we're slightly speeding the clocksource
1924 * in the code above, its possible the required corrective factor to
1925 * xtime_nsec could cause it to underflow.
1927 * Now, since we have already accumulated the second and the NTP
1928 * subsystem has been notified via second_overflow(), we need to skip
1931 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1932 tk->tkr_mono.xtime_nsec += (u64)NSEC_PER_SEC <<
1935 tk->skip_second_overflow = 1;
1940 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1942 * Helper function that accumulates the nsecs greater than a second
1943 * from the xtime_nsec field to the xtime_secs field.
1944 * It also calls into the NTP code to handle leapsecond processing.
1947 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1949 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1950 unsigned int clock_set = 0;
1952 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1955 tk->tkr_mono.xtime_nsec -= nsecps;
1959 * Skip NTP update if this second was accumulated before,
1960 * i.e. xtime_nsec underflowed in timekeeping_adjust()
1962 if (unlikely(tk->skip_second_overflow)) {
1963 tk->skip_second_overflow = 0;
1967 /* Figure out if its a leap sec and apply if needed */
1968 leap = second_overflow(tk->xtime_sec);
1969 if (unlikely(leap)) {
1970 struct timespec64 ts;
1972 tk->xtime_sec += leap;
1976 tk_set_wall_to_mono(tk,
1977 timespec64_sub(tk->wall_to_monotonic, ts));
1979 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1981 clock_set = TK_CLOCK_WAS_SET;
1988 * logarithmic_accumulation - shifted accumulation of cycles
1990 * This functions accumulates a shifted interval of cycles into
1991 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1994 * Returns the unconsumed cycles.
1996 static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
1997 u32 shift, unsigned int *clock_set)
1999 u64 interval = tk->cycle_interval << shift;
2002 /* If the offset is smaller than a shifted interval, do nothing */
2003 if (offset < interval)
2006 /* Accumulate one shifted interval */
2008 tk->tkr_mono.cycle_last += interval;
2009 tk->tkr_raw.cycle_last += interval;
2011 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2012 *clock_set |= accumulate_nsecs_to_secs(tk);
2014 /* Accumulate raw time */
2015 tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2016 snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2017 while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2018 tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2022 /* Accumulate error between NTP and clock interval */
2023 tk->ntp_error += tk->ntp_tick << shift;
2024 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2025 (tk->ntp_error_shift + shift);
2031 * update_wall_time - Uses the current clocksource to increment the wall time
2034 void update_wall_time(void)
2036 struct timekeeper *real_tk = &tk_core.timekeeper;
2037 struct timekeeper *tk = &shadow_timekeeper;
2039 int shift = 0, maxshift;
2040 unsigned int clock_set = 0;
2041 unsigned long flags;
2043 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2045 /* Make sure we're fully resumed: */
2046 if (unlikely(timekeeping_suspended))
2049 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2050 offset = real_tk->cycle_interval;
2052 offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2053 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2056 /* Check if there's really nothing to do */
2057 if (offset < real_tk->cycle_interval)
2060 /* Do some additional sanity checking */
2061 timekeeping_check_update(tk, offset);
2064 * With NO_HZ we may have to accumulate many cycle_intervals
2065 * (think "ticks") worth of time at once. To do this efficiently,
2066 * we calculate the largest doubling multiple of cycle_intervals
2067 * that is smaller than the offset. We then accumulate that
2068 * chunk in one go, and then try to consume the next smaller
2071 shift = ilog2(offset) - ilog2(tk->cycle_interval);
2072 shift = max(0, shift);
2073 /* Bound shift to one less than what overflows tick_length */
2074 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2075 shift = min(shift, maxshift);
2076 while (offset >= tk->cycle_interval) {
2077 offset = logarithmic_accumulation(tk, offset, shift,
2079 if (offset < tk->cycle_interval<<shift)
2083 /* Adjust the multiplier to correct NTP error */
2084 timekeeping_adjust(tk, offset);
2087 * Finally, make sure that after the rounding
2088 * xtime_nsec isn't larger than NSEC_PER_SEC
2090 clock_set |= accumulate_nsecs_to_secs(tk);
2092 write_seqcount_begin(&tk_core.seq);
2094 * Update the real timekeeper.
2096 * We could avoid this memcpy by switching pointers, but that
2097 * requires changes to all other timekeeper usage sites as
2098 * well, i.e. move the timekeeper pointer getter into the
2099 * spinlocked/seqcount protected sections. And we trade this
2100 * memcpy under the tk_core.seq against one before we start
2103 timekeeping_update(tk, clock_set);
2104 memcpy(real_tk, tk, sizeof(*tk));
2105 /* The memcpy must come last. Do not put anything here! */
2106 write_seqcount_end(&tk_core.seq);
2108 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2110 /* Have to call _delayed version, since in irq context*/
2111 clock_was_set_delayed();
2115 * getboottime64 - Return the real time of system boot.
2116 * @ts: pointer to the timespec64 to be set
2118 * Returns the wall-time of boot in a timespec64.
2120 * This is based on the wall_to_monotonic offset and the total suspend
2121 * time. Calls to settimeofday will affect the value returned (which
2122 * basically means that however wrong your real time clock is at boot time,
2123 * you get the right time here).
2125 void getboottime64(struct timespec64 *ts)
2127 struct timekeeper *tk = &tk_core.timekeeper;
2128 ktime_t t = ktime_sub(tk->offs_real, tk->time_suspended);
2130 *ts = ktime_to_timespec64(t);
2132 EXPORT_SYMBOL_GPL(getboottime64);
2134 unsigned long get_seconds(void)
2136 struct timekeeper *tk = &tk_core.timekeeper;
2138 return tk->xtime_sec;
2140 EXPORT_SYMBOL(get_seconds);
2142 struct timespec64 current_kernel_time64(void)
2144 struct timekeeper *tk = &tk_core.timekeeper;
2145 struct timespec64 now;
2149 seq = read_seqcount_begin(&tk_core.seq);
2152 } while (read_seqcount_retry(&tk_core.seq, seq));
2156 EXPORT_SYMBOL(current_kernel_time64);
2158 struct timespec64 get_monotonic_coarse64(void)
2160 struct timekeeper *tk = &tk_core.timekeeper;
2161 struct timespec64 now, mono;
2165 seq = read_seqcount_begin(&tk_core.seq);
2168 mono = tk->wall_to_monotonic;
2169 } while (read_seqcount_retry(&tk_core.seq, seq));
2171 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
2172 now.tv_nsec + mono.tv_nsec);
2176 EXPORT_SYMBOL(get_monotonic_coarse64);
2179 * Must hold jiffies_lock
2181 void do_timer(unsigned long ticks)
2183 jiffies_64 += ticks;
2184 calc_global_load(ticks);
2188 * ktime_get_update_offsets_now - hrtimer helper
2189 * @cwsseq: pointer to check and store the clock was set sequence number
2190 * @offs_real: pointer to storage for monotonic -> realtime offset
2191 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2193 * Returns current monotonic time and updates the offsets if the
2194 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2197 * Called from hrtimer_interrupt() or retrigger_next_event()
2199 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2202 struct timekeeper *tk = &tk_core.timekeeper;
2208 seq = read_seqcount_begin(&tk_core.seq);
2210 base = tk->tkr_mono.base;
2211 nsecs = timekeeping_get_ns(&tk->tkr_mono);
2212 base = ktime_add_ns(base, nsecs);
2214 if (*cwsseq != tk->clock_was_set_seq) {
2215 *cwsseq = tk->clock_was_set_seq;
2216 *offs_real = tk->offs_real;
2217 *offs_tai = tk->offs_tai;
2220 /* Handle leapsecond insertion adjustments */
2221 if (unlikely(base >= tk->next_leap_ktime))
2222 *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2224 } while (read_seqcount_retry(&tk_core.seq, seq));
2230 * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
2232 static int timekeeping_validate_timex(struct timex *txc)
2234 if (txc->modes & ADJ_ADJTIME) {
2235 /* singleshot must not be used with any other mode bits */
2236 if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
2238 if (!(txc->modes & ADJ_OFFSET_READONLY) &&
2239 !capable(CAP_SYS_TIME))
2242 /* In order to modify anything, you gotta be super-user! */
2243 if (txc->modes && !capable(CAP_SYS_TIME))
2246 * if the quartz is off by more than 10% then
2247 * something is VERY wrong!
2249 if (txc->modes & ADJ_TICK &&
2250 (txc->tick < 900000/USER_HZ ||
2251 txc->tick > 1100000/USER_HZ))
2255 if (txc->modes & ADJ_SETOFFSET) {
2256 /* In order to inject time, you gotta be super-user! */
2257 if (!capable(CAP_SYS_TIME))
2261 * Validate if a timespec/timeval used to inject a time
2262 * offset is valid. Offsets can be postive or negative, so
2263 * we don't check tv_sec. The value of the timeval/timespec
2264 * is the sum of its fields,but *NOTE*:
2265 * The field tv_usec/tv_nsec must always be non-negative and
2266 * we can't have more nanoseconds/microseconds than a second.
2268 if (txc->time.tv_usec < 0)
2271 if (txc->modes & ADJ_NANO) {
2272 if (txc->time.tv_usec >= NSEC_PER_SEC)
2275 if (txc->time.tv_usec >= USEC_PER_SEC)
2281 * Check for potential multiplication overflows that can
2282 * only happen on 64-bit systems:
2284 if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
2285 if (LLONG_MIN / PPM_SCALE > txc->freq)
2287 if (LLONG_MAX / PPM_SCALE < txc->freq)
2296 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2298 int do_adjtimex(struct timex *txc)
2300 struct timekeeper *tk = &tk_core.timekeeper;
2301 unsigned long flags;
2302 struct timespec64 ts;
2306 /* Validate the data before disabling interrupts */
2307 ret = timekeeping_validate_timex(txc);
2311 if (txc->modes & ADJ_SETOFFSET) {
2312 struct timespec64 delta;
2313 delta.tv_sec = txc->time.tv_sec;
2314 delta.tv_nsec = txc->time.tv_usec;
2315 if (!(txc->modes & ADJ_NANO))
2316 delta.tv_nsec *= 1000;
2317 ret = timekeeping_inject_offset(&delta);
2322 getnstimeofday64(&ts);
2324 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2325 write_seqcount_begin(&tk_core.seq);
2327 orig_tai = tai = tk->tai_offset;
2328 ret = __do_adjtimex(txc, &ts, &tai);
2330 if (tai != orig_tai) {
2331 __timekeeping_set_tai_offset(tk, tai);
2332 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2334 tk_update_leap_state(tk);
2336 write_seqcount_end(&tk_core.seq);
2337 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2339 if (tai != orig_tai)
2342 ntp_notify_cmos_timer();
2347 #ifdef CONFIG_NTP_PPS
2349 * hardpps() - Accessor function to NTP __hardpps function
2351 void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2353 unsigned long flags;
2355 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2356 write_seqcount_begin(&tk_core.seq);
2358 __hardpps(phase_ts, raw_ts);
2360 write_seqcount_end(&tk_core.seq);
2361 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2363 EXPORT_SYMBOL(hardpps);
2364 #endif /* CONFIG_NTP_PPS */
2367 * xtime_update() - advances the timekeeping infrastructure
2368 * @ticks: number of ticks, that have elapsed since the last call.
2370 * Must be called with interrupts disabled.
2372 void xtime_update(unsigned long ticks)
2374 write_seqlock(&jiffies_lock);
2376 write_sequnlock(&jiffies_lock);