2 * linux/kernel/time/timekeeping.c
4 * Kernel timekeeping code and accessor functions
6 * This code was moved from linux/kernel/timer.c.
7 * Please see that file for copyright and history logs.
11 #include <linux/timekeeper_internal.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include <linux/percpu.h>
15 #include <linux/init.h>
17 #include <linux/sched.h>
18 #include <linux/syscore_ops.h>
19 #include <linux/clocksource.h>
20 #include <linux/jiffies.h>
21 #include <linux/time.h>
22 #include <linux/tick.h>
23 #include <linux/stop_machine.h>
24 #include <linux/pvclock_gtod.h>
25 #include <linux/compiler.h>
27 #include "tick-internal.h"
28 #include "ntp_internal.h"
29 #include "timekeeping_internal.h"
31 #define TK_CLEAR_NTP (1 << 0)
32 #define TK_MIRROR (1 << 1)
33 #define TK_CLOCK_WAS_SET (1 << 2)
36 * The most important data for readout fits into a single 64 byte
41 struct timekeeper timekeeper;
42 } tk_core ____cacheline_aligned = {
43 .seq = SEQCNT_ZERO(tk_core.seq),
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 static struct tk_fast tk_fast_mono ____cacheline_aligned;
64 static struct tk_fast tk_fast_raw ____cacheline_aligned;
66 /* flag for if timekeeping is suspended */
67 int __read_mostly timekeeping_suspended;
69 static inline void tk_normalize_xtime(struct timekeeper *tk)
71 while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
72 tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
77 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
81 ts.tv_sec = tk->xtime_sec;
82 ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
86 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
88 tk->xtime_sec = ts->tv_sec;
89 tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
92 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
94 tk->xtime_sec += ts->tv_sec;
95 tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
96 tk_normalize_xtime(tk);
99 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
101 struct timespec64 tmp;
104 * Verify consistency of: offset_real = -wall_to_monotonic
105 * before modifying anything
107 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
108 -tk->wall_to_monotonic.tv_nsec);
109 WARN_ON_ONCE(tk->offs_real.tv64 != timespec64_to_ktime(tmp).tv64);
110 tk->wall_to_monotonic = wtm;
111 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
112 tk->offs_real = timespec64_to_ktime(tmp);
113 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
116 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
118 tk->offs_boot = ktime_add(tk->offs_boot, delta);
122 * tk_clock_read - atomic clocksource read() helper
124 * This helper is necessary to use in the read paths because, while the
125 * seqlock ensures we don't return a bad value while structures are updated,
126 * it doesn't protect from potential crashes. There is the possibility that
127 * the tkr's clocksource may change between the read reference, and the
128 * clock reference passed to the read function. This can cause crashes if
129 * the wrong clocksource is passed to the wrong read function.
130 * This isn't necessary to use when holding the timekeeper_lock or doing
131 * a read of the fast-timekeeper tkrs (which is protected by its own locking
134 static inline u64 tk_clock_read(struct tk_read_base *tkr)
136 struct clocksource *clock = READ_ONCE(tkr->clock);
138 return clock->read(clock);
141 #ifdef CONFIG_DEBUG_TIMEKEEPING
142 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
144 static void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
147 cycle_t max_cycles = tk->tkr_mono.clock->max_cycles;
148 const char *name = tk->tkr_mono.clock->name;
150 if (offset > max_cycles) {
151 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
152 offset, name, max_cycles);
153 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
155 if (offset > (max_cycles >> 1)) {
156 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
157 offset, name, max_cycles >> 1);
158 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
162 if (tk->underflow_seen) {
163 if (jiffies - tk->last_warning > WARNING_FREQ) {
164 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
165 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
166 printk_deferred(" Your kernel is probably still fine.\n");
167 tk->last_warning = jiffies;
169 tk->underflow_seen = 0;
172 if (tk->overflow_seen) {
173 if (jiffies - tk->last_warning > WARNING_FREQ) {
174 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
175 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
176 printk_deferred(" Your kernel is probably still fine.\n");
177 tk->last_warning = jiffies;
179 tk->overflow_seen = 0;
183 static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
185 struct timekeeper *tk = &tk_core.timekeeper;
186 cycle_t now, last, mask, max, delta;
190 * Since we're called holding a seqlock, the data may shift
191 * under us while we're doing the calculation. This can cause
192 * false positives, since we'd note a problem but throw the
193 * results away. So nest another seqlock here to atomically
194 * grab the points we are checking with.
197 seq = read_seqcount_begin(&tk_core.seq);
198 now = tk_clock_read(tkr);
199 last = tkr->cycle_last;
201 max = tkr->clock->max_cycles;
202 } while (read_seqcount_retry(&tk_core.seq, seq));
204 delta = clocksource_delta(now, last, mask);
207 * Try to catch underflows by checking if we are seeing small
208 * mask-relative negative values.
210 if (unlikely((~delta & mask) < (mask >> 3))) {
211 tk->underflow_seen = 1;
215 /* Cap delta value to the max_cycles values to avoid mult overflows */
216 if (unlikely(delta > max)) {
217 tk->overflow_seen = 1;
218 delta = tkr->clock->max_cycles;
224 static inline void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
227 static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
229 cycle_t cycle_now, delta;
231 /* read clocksource */
232 cycle_now = tk_clock_read(tkr);
234 /* calculate the delta since the last update_wall_time */
235 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
242 * tk_setup_internals - Set up internals to use clocksource clock.
244 * @tk: The target timekeeper to setup.
245 * @clock: Pointer to clocksource.
247 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
248 * pair and interval request.
250 * Unless you're the timekeeping code, you should not be using this!
252 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
255 u64 tmp, ntpinterval;
256 struct clocksource *old_clock;
258 ++tk->cs_was_changed_seq;
259 old_clock = tk->tkr_mono.clock;
260 tk->tkr_mono.clock = clock;
261 tk->tkr_mono.mask = clock->mask;
262 tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
264 tk->tkr_raw.clock = clock;
265 tk->tkr_raw.mask = clock->mask;
266 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
268 /* Do the ns -> cycle conversion first, using original mult */
269 tmp = NTP_INTERVAL_LENGTH;
270 tmp <<= clock->shift;
272 tmp += clock->mult/2;
273 do_div(tmp, clock->mult);
277 interval = (cycle_t) tmp;
278 tk->cycle_interval = interval;
280 /* Go back from cycles -> shifted ns */
281 tk->xtime_interval = (u64) interval * clock->mult;
282 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
283 tk->raw_interval = interval * clock->mult;
285 /* if changing clocks, convert xtime_nsec shift units */
287 int shift_change = clock->shift - old_clock->shift;
288 if (shift_change < 0)
289 tk->tkr_mono.xtime_nsec >>= -shift_change;
291 tk->tkr_mono.xtime_nsec <<= shift_change;
293 tk->tkr_raw.xtime_nsec = 0;
295 tk->tkr_mono.shift = clock->shift;
296 tk->tkr_raw.shift = clock->shift;
299 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
300 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
303 * The timekeeper keeps its own mult values for the currently
304 * active clocksource. These value will be adjusted via NTP
305 * to counteract clock drifting.
307 tk->tkr_mono.mult = clock->mult;
308 tk->tkr_raw.mult = clock->mult;
309 tk->ntp_err_mult = 0;
312 /* Timekeeper helper functions. */
314 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
315 static u32 default_arch_gettimeoffset(void) { return 0; }
316 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
318 static inline u32 arch_gettimeoffset(void) { return 0; }
321 static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr,
326 nsec = delta * tkr->mult + tkr->xtime_nsec;
329 /* If arch requires, add in get_arch_timeoffset() */
330 return nsec + arch_gettimeoffset();
333 static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
337 delta = timekeeping_get_delta(tkr);
338 return timekeeping_delta_to_ns(tkr, delta);
341 static inline s64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
346 /* calculate the delta since the last update_wall_time */
347 delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
348 return timekeeping_delta_to_ns(tkr, delta);
352 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
353 * @tkr: Timekeeping readout base from which we take the update
355 * We want to use this from any context including NMI and tracing /
356 * instrumenting the timekeeping code itself.
358 * Employ the latch technique; see @raw_write_seqcount_latch.
360 * So if a NMI hits the update of base[0] then it will use base[1]
361 * which is still consistent. In the worst case this can result is a
362 * slightly wrong timestamp (a few nanoseconds). See
363 * @ktime_get_mono_fast_ns.
365 static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
367 struct tk_read_base *base = tkf->base;
369 /* Force readers off to base[1] */
370 raw_write_seqcount_latch(&tkf->seq);
373 memcpy(base, tkr, sizeof(*base));
375 /* Force readers back to base[0] */
376 raw_write_seqcount_latch(&tkf->seq);
379 memcpy(base + 1, base, sizeof(*base));
383 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
385 * This timestamp is not guaranteed to be monotonic across an update.
386 * The timestamp is calculated by:
388 * now = base_mono + clock_delta * slope
390 * So if the update lowers the slope, readers who are forced to the
391 * not yet updated second array are still using the old steeper slope.
400 * |12345678---> reader order
406 * So reader 6 will observe time going backwards versus reader 5.
408 * While other CPUs are likely to be able observe that, the only way
409 * for a CPU local observation is when an NMI hits in the middle of
410 * the update. Timestamps taken from that NMI context might be ahead
411 * of the following timestamps. Callers need to be aware of that and
414 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
416 struct tk_read_base *tkr;
421 seq = raw_read_seqcount_latch(&tkf->seq);
422 tkr = tkf->base + (seq & 0x01);
423 now = ktime_to_ns(tkr->base);
425 now += timekeeping_delta_to_ns(tkr,
430 } while (read_seqcount_retry(&tkf->seq, seq));
435 u64 ktime_get_mono_fast_ns(void)
437 return __ktime_get_fast_ns(&tk_fast_mono);
439 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
441 u64 ktime_get_raw_fast_ns(void)
443 return __ktime_get_fast_ns(&tk_fast_raw);
445 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
447 /* Suspend-time cycles value for halted fast timekeeper. */
448 static cycle_t cycles_at_suspend;
450 static cycle_t dummy_clock_read(struct clocksource *cs)
452 return cycles_at_suspend;
455 static struct clocksource dummy_clock = {
456 .read = dummy_clock_read,
460 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
461 * @tk: Timekeeper to snapshot.
463 * It generally is unsafe to access the clocksource after timekeeping has been
464 * suspended, so take a snapshot of the readout base of @tk and use it as the
465 * fast timekeeper's readout base while suspended. It will return the same
466 * number of cycles every time until timekeeping is resumed at which time the
467 * proper readout base for the fast timekeeper will be restored automatically.
469 static void halt_fast_timekeeper(struct timekeeper *tk)
471 static struct tk_read_base tkr_dummy;
472 struct tk_read_base *tkr = &tk->tkr_mono;
474 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
475 cycles_at_suspend = tk_clock_read(tkr);
476 tkr_dummy.clock = &dummy_clock;
477 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
480 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
481 tkr_dummy.clock = &dummy_clock;
482 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
485 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
487 static inline void update_vsyscall(struct timekeeper *tk)
489 struct timespec xt, wm;
491 xt = timespec64_to_timespec(tk_xtime(tk));
492 wm = timespec64_to_timespec(tk->wall_to_monotonic);
493 update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult,
494 tk->tkr_mono.cycle_last);
497 static inline void old_vsyscall_fixup(struct timekeeper *tk)
502 * Store only full nanoseconds into xtime_nsec after rounding
503 * it up and add the remainder to the error difference.
504 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
505 * by truncating the remainder in vsyscalls. However, it causes
506 * additional work to be done in timekeeping_adjust(). Once
507 * the vsyscall implementations are converted to use xtime_nsec
508 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
509 * users are removed, this can be killed.
511 remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1);
512 if (remainder != 0) {
513 tk->tkr_mono.xtime_nsec -= remainder;
514 tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift;
515 tk->ntp_error += remainder << tk->ntp_error_shift;
516 tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift;
520 #define old_vsyscall_fixup(tk)
523 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
525 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
527 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
531 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
533 int pvclock_gtod_register_notifier(struct notifier_block *nb)
535 struct timekeeper *tk = &tk_core.timekeeper;
539 raw_spin_lock_irqsave(&timekeeper_lock, flags);
540 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
541 update_pvclock_gtod(tk, true);
542 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
546 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
549 * pvclock_gtod_unregister_notifier - unregister a pvclock
550 * timedata update listener
552 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
557 raw_spin_lock_irqsave(&timekeeper_lock, flags);
558 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
559 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
563 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
566 * tk_update_leap_state - helper to update the next_leap_ktime
568 static inline void tk_update_leap_state(struct timekeeper *tk)
570 tk->next_leap_ktime = ntp_get_next_leap();
571 if (tk->next_leap_ktime.tv64 != KTIME_MAX)
572 /* Convert to monotonic time */
573 tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
577 * Update the ktime_t based scalar nsec members of the timekeeper
579 static inline void tk_update_ktime_data(struct timekeeper *tk)
585 * The xtime based monotonic readout is:
586 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
587 * The ktime based monotonic readout is:
588 * nsec = base_mono + now();
589 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
591 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
592 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
593 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
595 /* Update the monotonic raw base */
596 tk->tkr_raw.base = timespec64_to_ktime(tk->raw_time);
599 * The sum of the nanoseconds portions of xtime and
600 * wall_to_monotonic can be greater/equal one second. Take
601 * this into account before updating tk->ktime_sec.
603 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
604 if (nsec >= NSEC_PER_SEC)
606 tk->ktime_sec = seconds;
609 /* must hold timekeeper_lock */
610 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
612 if (action & TK_CLEAR_NTP) {
617 tk_update_leap_state(tk);
618 tk_update_ktime_data(tk);
621 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
623 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
624 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
626 if (action & TK_CLOCK_WAS_SET)
627 tk->clock_was_set_seq++;
629 * The mirroring of the data to the shadow-timekeeper needs
630 * to happen last here to ensure we don't over-write the
631 * timekeeper structure on the next update with stale data
633 if (action & TK_MIRROR)
634 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
635 sizeof(tk_core.timekeeper));
639 * timekeeping_forward_now - update clock to the current time
641 * Forward the current clock to update its state since the last call to
642 * update_wall_time(). This is useful before significant clock changes,
643 * as it avoids having to deal with this time offset explicitly.
645 static void timekeeping_forward_now(struct timekeeper *tk)
647 cycle_t cycle_now, delta;
650 cycle_now = tk_clock_read(&tk->tkr_mono);
651 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
652 tk->tkr_mono.cycle_last = cycle_now;
653 tk->tkr_raw.cycle_last = cycle_now;
655 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
657 /* If arch requires, add in get_arch_timeoffset() */
658 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
660 tk_normalize_xtime(tk);
662 nsec = clocksource_cyc2ns(delta, tk->tkr_raw.mult, tk->tkr_raw.shift);
663 timespec64_add_ns(&tk->raw_time, nsec);
667 * __getnstimeofday64 - Returns the time of day in a timespec64.
668 * @ts: pointer to the timespec to be set
670 * Updates the time of day in the timespec.
671 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
673 int __getnstimeofday64(struct timespec64 *ts)
675 struct timekeeper *tk = &tk_core.timekeeper;
680 seq = read_seqcount_begin(&tk_core.seq);
682 ts->tv_sec = tk->xtime_sec;
683 nsecs = timekeeping_get_ns(&tk->tkr_mono);
685 } while (read_seqcount_retry(&tk_core.seq, seq));
688 timespec64_add_ns(ts, nsecs);
691 * Do not bail out early, in case there were callers still using
692 * the value, even in the face of the WARN_ON.
694 if (unlikely(timekeeping_suspended))
698 EXPORT_SYMBOL(__getnstimeofday64);
701 * getnstimeofday64 - Returns the time of day in a timespec64.
702 * @ts: pointer to the timespec64 to be set
704 * Returns the time of day in a timespec64 (WARN if suspended).
706 void getnstimeofday64(struct timespec64 *ts)
708 WARN_ON(__getnstimeofday64(ts));
710 EXPORT_SYMBOL(getnstimeofday64);
712 ktime_t ktime_get(void)
714 struct timekeeper *tk = &tk_core.timekeeper;
719 WARN_ON(timekeeping_suspended);
722 seq = read_seqcount_begin(&tk_core.seq);
723 base = tk->tkr_mono.base;
724 nsecs = timekeeping_get_ns(&tk->tkr_mono);
726 } while (read_seqcount_retry(&tk_core.seq, seq));
728 return ktime_add_ns(base, nsecs);
730 EXPORT_SYMBOL_GPL(ktime_get);
732 u32 ktime_get_resolution_ns(void)
734 struct timekeeper *tk = &tk_core.timekeeper;
738 WARN_ON(timekeeping_suspended);
741 seq = read_seqcount_begin(&tk_core.seq);
742 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
743 } while (read_seqcount_retry(&tk_core.seq, seq));
747 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
749 static ktime_t *offsets[TK_OFFS_MAX] = {
750 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
751 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
752 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
755 ktime_t ktime_get_with_offset(enum tk_offsets offs)
757 struct timekeeper *tk = &tk_core.timekeeper;
759 ktime_t base, *offset = offsets[offs];
762 WARN_ON(timekeeping_suspended);
765 seq = read_seqcount_begin(&tk_core.seq);
766 base = ktime_add(tk->tkr_mono.base, *offset);
767 nsecs = timekeeping_get_ns(&tk->tkr_mono);
769 } while (read_seqcount_retry(&tk_core.seq, seq));
771 return ktime_add_ns(base, nsecs);
774 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
777 * ktime_mono_to_any() - convert mononotic time to any other time
778 * @tmono: time to convert.
779 * @offs: which offset to use
781 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
783 ktime_t *offset = offsets[offs];
788 seq = read_seqcount_begin(&tk_core.seq);
789 tconv = ktime_add(tmono, *offset);
790 } while (read_seqcount_retry(&tk_core.seq, seq));
794 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
797 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
799 ktime_t ktime_get_raw(void)
801 struct timekeeper *tk = &tk_core.timekeeper;
807 seq = read_seqcount_begin(&tk_core.seq);
808 base = tk->tkr_raw.base;
809 nsecs = timekeeping_get_ns(&tk->tkr_raw);
811 } while (read_seqcount_retry(&tk_core.seq, seq));
813 return ktime_add_ns(base, nsecs);
815 EXPORT_SYMBOL_GPL(ktime_get_raw);
818 * ktime_get_ts64 - get the monotonic clock in timespec64 format
819 * @ts: pointer to timespec variable
821 * The function calculates the monotonic clock from the realtime
822 * clock and the wall_to_monotonic offset and stores the result
823 * in normalized timespec64 format in the variable pointed to by @ts.
825 void ktime_get_ts64(struct timespec64 *ts)
827 struct timekeeper *tk = &tk_core.timekeeper;
828 struct timespec64 tomono;
832 WARN_ON(timekeeping_suspended);
835 seq = read_seqcount_begin(&tk_core.seq);
836 ts->tv_sec = tk->xtime_sec;
837 nsec = timekeeping_get_ns(&tk->tkr_mono);
838 tomono = tk->wall_to_monotonic;
840 } while (read_seqcount_retry(&tk_core.seq, seq));
842 ts->tv_sec += tomono.tv_sec;
844 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
846 EXPORT_SYMBOL_GPL(ktime_get_ts64);
849 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
851 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
852 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
853 * works on both 32 and 64 bit systems. On 32 bit systems the readout
854 * covers ~136 years of uptime which should be enough to prevent
855 * premature wrap arounds.
857 time64_t ktime_get_seconds(void)
859 struct timekeeper *tk = &tk_core.timekeeper;
861 WARN_ON(timekeeping_suspended);
862 return tk->ktime_sec;
864 EXPORT_SYMBOL_GPL(ktime_get_seconds);
867 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
869 * Returns the wall clock seconds since 1970. This replaces the
870 * get_seconds() interface which is not y2038 safe on 32bit systems.
872 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
873 * 32bit systems the access must be protected with the sequence
874 * counter to provide "atomic" access to the 64bit tk->xtime_sec
877 time64_t ktime_get_real_seconds(void)
879 struct timekeeper *tk = &tk_core.timekeeper;
883 if (IS_ENABLED(CONFIG_64BIT))
884 return tk->xtime_sec;
887 seq = read_seqcount_begin(&tk_core.seq);
888 seconds = tk->xtime_sec;
890 } while (read_seqcount_retry(&tk_core.seq, seq));
894 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
897 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
898 * but without the sequence counter protect. This internal function
899 * is called just when timekeeping lock is already held.
901 time64_t __ktime_get_real_seconds(void)
903 struct timekeeper *tk = &tk_core.timekeeper;
905 return tk->xtime_sec;
909 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
910 * @systime_snapshot: pointer to struct receiving the system time snapshot
912 void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
914 struct timekeeper *tk = &tk_core.timekeeper;
922 WARN_ON_ONCE(timekeeping_suspended);
925 seq = read_seqcount_begin(&tk_core.seq);
926 now = tk_clock_read(&tk->tkr_mono);
927 systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
928 systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
929 base_real = ktime_add(tk->tkr_mono.base,
930 tk_core.timekeeper.offs_real);
931 base_raw = tk->tkr_raw.base;
932 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
933 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
934 } while (read_seqcount_retry(&tk_core.seq, seq));
936 systime_snapshot->cycles = now;
937 systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
938 systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
940 EXPORT_SYMBOL_GPL(ktime_get_snapshot);
942 /* Scale base by mult/div checking for overflow */
943 static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
947 tmp = div64_u64_rem(*base, div, &rem);
949 if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
950 ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
954 rem = div64_u64(rem * mult, div);
960 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
961 * @history: Snapshot representing start of history
962 * @partial_history_cycles: Cycle offset into history (fractional part)
963 * @total_history_cycles: Total history length in cycles
964 * @discontinuity: True indicates clock was set on history period
965 * @ts: Cross timestamp that should be adjusted using
966 * partial/total ratio
968 * Helper function used by get_device_system_crosststamp() to correct the
969 * crosstimestamp corresponding to the start of the current interval to the
970 * system counter value (timestamp point) provided by the driver. The
971 * total_history_* quantities are the total history starting at the provided
972 * reference point and ending at the start of the current interval. The cycle
973 * count between the driver timestamp point and the start of the current
974 * interval is partial_history_cycles.
976 static int adjust_historical_crosststamp(struct system_time_snapshot *history,
977 cycle_t partial_history_cycles,
978 cycle_t total_history_cycles,
980 struct system_device_crosststamp *ts)
982 struct timekeeper *tk = &tk_core.timekeeper;
983 u64 corr_raw, corr_real;
987 if (total_history_cycles == 0 || partial_history_cycles == 0)
990 /* Interpolate shortest distance from beginning or end of history */
991 interp_forward = partial_history_cycles > total_history_cycles/2 ?
993 partial_history_cycles = interp_forward ?
994 total_history_cycles - partial_history_cycles :
995 partial_history_cycles;
998 * Scale the monotonic raw time delta by:
999 * partial_history_cycles / total_history_cycles
1001 corr_raw = (u64)ktime_to_ns(
1002 ktime_sub(ts->sys_monoraw, history->raw));
1003 ret = scale64_check_overflow(partial_history_cycles,
1004 total_history_cycles, &corr_raw);
1009 * If there is a discontinuity in the history, scale monotonic raw
1011 * mult(real)/mult(raw) yielding the realtime correction
1012 * Otherwise, calculate the realtime correction similar to monotonic
1015 if (discontinuity) {
1016 corr_real = mul_u64_u32_div
1017 (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1019 corr_real = (u64)ktime_to_ns(
1020 ktime_sub(ts->sys_realtime, history->real));
1021 ret = scale64_check_overflow(partial_history_cycles,
1022 total_history_cycles, &corr_real);
1027 /* Fixup monotonic raw and real time time values */
1028 if (interp_forward) {
1029 ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1030 ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1032 ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1033 ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1040 * cycle_between - true if test occurs chronologically between before and after
1042 static bool cycle_between(cycle_t before, cycle_t test, cycle_t after)
1044 if (test > before && test < after)
1046 if (test < before && before > after)
1052 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1053 * @get_time_fn: Callback to get simultaneous device time and
1054 * system counter from the device driver
1055 * @ctx: Context passed to get_time_fn()
1056 * @history_begin: Historical reference point used to interpolate system
1057 * time when counter provided by the driver is before the current interval
1058 * @xtstamp: Receives simultaneously captured system and device time
1060 * Reads a timestamp from a device and correlates it to system time
1062 int get_device_system_crosststamp(int (*get_time_fn)
1063 (ktime_t *device_time,
1064 struct system_counterval_t *sys_counterval,
1067 struct system_time_snapshot *history_begin,
1068 struct system_device_crosststamp *xtstamp)
1070 struct system_counterval_t system_counterval;
1071 struct timekeeper *tk = &tk_core.timekeeper;
1072 cycle_t cycles, now, interval_start;
1073 unsigned int clock_was_set_seq = 0;
1074 ktime_t base_real, base_raw;
1075 s64 nsec_real, nsec_raw;
1076 u8 cs_was_changed_seq;
1082 seq = read_seqcount_begin(&tk_core.seq);
1084 * Try to synchronously capture device time and a system
1085 * counter value calling back into the device driver
1087 ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1092 * Verify that the clocksource associated with the captured
1093 * system counter value is the same as the currently installed
1094 * timekeeper clocksource
1096 if (tk->tkr_mono.clock != system_counterval.cs)
1098 cycles = system_counterval.cycles;
1101 * Check whether the system counter value provided by the
1102 * device driver is on the current timekeeping interval.
1104 now = tk_clock_read(&tk->tkr_mono);
1105 interval_start = tk->tkr_mono.cycle_last;
1106 if (!cycle_between(interval_start, cycles, now)) {
1107 clock_was_set_seq = tk->clock_was_set_seq;
1108 cs_was_changed_seq = tk->cs_was_changed_seq;
1109 cycles = interval_start;
1115 base_real = ktime_add(tk->tkr_mono.base,
1116 tk_core.timekeeper.offs_real);
1117 base_raw = tk->tkr_raw.base;
1119 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1120 system_counterval.cycles);
1121 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1122 system_counterval.cycles);
1123 } while (read_seqcount_retry(&tk_core.seq, seq));
1125 xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1126 xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1129 * Interpolate if necessary, adjusting back from the start of the
1133 cycle_t partial_history_cycles, total_history_cycles;
1137 * Check that the counter value occurs after the provided
1138 * history reference and that the history doesn't cross a
1139 * clocksource change
1141 if (!history_begin ||
1142 !cycle_between(history_begin->cycles,
1143 system_counterval.cycles, cycles) ||
1144 history_begin->cs_was_changed_seq != cs_was_changed_seq)
1146 partial_history_cycles = cycles - system_counterval.cycles;
1147 total_history_cycles = cycles - history_begin->cycles;
1149 history_begin->clock_was_set_seq != clock_was_set_seq;
1151 ret = adjust_historical_crosststamp(history_begin,
1152 partial_history_cycles,
1153 total_history_cycles,
1154 discontinuity, xtstamp);
1161 EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1164 * do_gettimeofday - Returns the time of day in a timeval
1165 * @tv: pointer to the timeval to be set
1167 * NOTE: Users should be converted to using getnstimeofday()
1169 void do_gettimeofday(struct timeval *tv)
1171 struct timespec64 now;
1173 getnstimeofday64(&now);
1174 tv->tv_sec = now.tv_sec;
1175 tv->tv_usec = now.tv_nsec/1000;
1177 EXPORT_SYMBOL(do_gettimeofday);
1180 * do_settimeofday64 - Sets the time of day.
1181 * @ts: pointer to the timespec64 variable containing the new time
1183 * Sets the time of day to the new time and update NTP and notify hrtimers
1185 int do_settimeofday64(const struct timespec64 *ts)
1187 struct timekeeper *tk = &tk_core.timekeeper;
1188 struct timespec64 ts_delta, xt;
1189 unsigned long flags;
1192 if (!timespec64_valid_strict(ts))
1195 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1196 write_seqcount_begin(&tk_core.seq);
1198 timekeeping_forward_now(tk);
1201 ts_delta = timespec64_sub(*ts, xt);
1203 if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1208 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1210 tk_set_xtime(tk, ts);
1212 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1214 write_seqcount_end(&tk_core.seq);
1215 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1217 /* signal hrtimers about time change */
1222 EXPORT_SYMBOL(do_settimeofday64);
1225 * timekeeping_inject_offset - Adds or subtracts from the current time.
1226 * @tv: pointer to the timespec variable containing the offset
1228 * Adds or subtracts an offset value from the current time.
1230 int timekeeping_inject_offset(struct timespec *ts)
1232 struct timekeeper *tk = &tk_core.timekeeper;
1233 unsigned long flags;
1234 struct timespec64 ts64, tmp;
1237 if (!timespec_inject_offset_valid(ts))
1240 ts64 = timespec_to_timespec64(*ts);
1242 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1243 write_seqcount_begin(&tk_core.seq);
1245 timekeeping_forward_now(tk);
1247 /* Make sure the proposed value is valid */
1248 tmp = timespec64_add(tk_xtime(tk), ts64);
1249 if (timespec64_compare(&tk->wall_to_monotonic, &ts64) > 0 ||
1250 !timespec64_valid_strict(&tmp)) {
1255 tk_xtime_add(tk, &ts64);
1256 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
1258 error: /* even if we error out, we forwarded the time, so call update */
1259 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1261 write_seqcount_end(&tk_core.seq);
1262 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1264 /* signal hrtimers about time change */
1269 EXPORT_SYMBOL(timekeeping_inject_offset);
1273 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
1276 s32 timekeeping_get_tai_offset(void)
1278 struct timekeeper *tk = &tk_core.timekeeper;
1283 seq = read_seqcount_begin(&tk_core.seq);
1284 ret = tk->tai_offset;
1285 } while (read_seqcount_retry(&tk_core.seq, seq));
1291 * __timekeeping_set_tai_offset - Lock free worker function
1294 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1296 tk->tai_offset = tai_offset;
1297 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1301 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
1304 void timekeeping_set_tai_offset(s32 tai_offset)
1306 struct timekeeper *tk = &tk_core.timekeeper;
1307 unsigned long flags;
1309 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1310 write_seqcount_begin(&tk_core.seq);
1311 __timekeeping_set_tai_offset(tk, tai_offset);
1312 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1313 write_seqcount_end(&tk_core.seq);
1314 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1319 * change_clocksource - Swaps clocksources if a new one is available
1321 * Accumulates current time interval and initializes new clocksource
1323 static int change_clocksource(void *data)
1325 struct timekeeper *tk = &tk_core.timekeeper;
1326 struct clocksource *new, *old;
1327 unsigned long flags;
1329 new = (struct clocksource *) data;
1331 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1332 write_seqcount_begin(&tk_core.seq);
1334 timekeeping_forward_now(tk);
1336 * If the cs is in module, get a module reference. Succeeds
1337 * for built-in code (owner == NULL) as well.
1339 if (try_module_get(new->owner)) {
1340 if (!new->enable || new->enable(new) == 0) {
1341 old = tk->tkr_mono.clock;
1342 tk_setup_internals(tk, new);
1345 module_put(old->owner);
1347 module_put(new->owner);
1350 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1352 write_seqcount_end(&tk_core.seq);
1353 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1359 * timekeeping_notify - Install a new clock source
1360 * @clock: pointer to the clock source
1362 * This function is called from clocksource.c after a new, better clock
1363 * source has been registered. The caller holds the clocksource_mutex.
1365 int timekeeping_notify(struct clocksource *clock)
1367 struct timekeeper *tk = &tk_core.timekeeper;
1369 if (tk->tkr_mono.clock == clock)
1371 stop_machine(change_clocksource, clock, NULL);
1372 tick_clock_notify();
1373 return tk->tkr_mono.clock == clock ? 0 : -1;
1377 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1378 * @ts: pointer to the timespec64 to be set
1380 * Returns the raw monotonic time (completely un-modified by ntp)
1382 void getrawmonotonic64(struct timespec64 *ts)
1384 struct timekeeper *tk = &tk_core.timekeeper;
1385 struct timespec64 ts64;
1390 seq = read_seqcount_begin(&tk_core.seq);
1391 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1392 ts64 = tk->raw_time;
1394 } while (read_seqcount_retry(&tk_core.seq, seq));
1396 timespec64_add_ns(&ts64, nsecs);
1399 EXPORT_SYMBOL(getrawmonotonic64);
1403 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1405 int timekeeping_valid_for_hres(void)
1407 struct timekeeper *tk = &tk_core.timekeeper;
1412 seq = read_seqcount_begin(&tk_core.seq);
1414 ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1416 } while (read_seqcount_retry(&tk_core.seq, seq));
1422 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1424 u64 timekeeping_max_deferment(void)
1426 struct timekeeper *tk = &tk_core.timekeeper;
1431 seq = read_seqcount_begin(&tk_core.seq);
1433 ret = tk->tkr_mono.clock->max_idle_ns;
1435 } while (read_seqcount_retry(&tk_core.seq, seq));
1441 * read_persistent_clock - Return time from the persistent clock.
1443 * Weak dummy function for arches that do not yet support it.
1444 * Reads the time from the battery backed persistent clock.
1445 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1447 * XXX - Do be sure to remove it once all arches implement it.
1449 void __weak read_persistent_clock(struct timespec *ts)
1455 void __weak read_persistent_clock64(struct timespec64 *ts64)
1459 read_persistent_clock(&ts);
1460 *ts64 = timespec_to_timespec64(ts);
1464 * read_boot_clock64 - Return time of the system start.
1466 * Weak dummy function for arches that do not yet support it.
1467 * Function to read the exact time the system has been started.
1468 * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported.
1470 * XXX - Do be sure to remove it once all arches implement it.
1472 void __weak read_boot_clock64(struct timespec64 *ts)
1478 /* Flag for if timekeeping_resume() has injected sleeptime */
1479 static bool sleeptime_injected;
1481 /* Flag for if there is a persistent clock on this platform */
1482 static bool persistent_clock_exists;
1485 * timekeeping_init - Initializes the clocksource and common timekeeping values
1487 void __init timekeeping_init(void)
1489 struct timekeeper *tk = &tk_core.timekeeper;
1490 struct clocksource *clock;
1491 unsigned long flags;
1492 struct timespec64 now, boot, tmp;
1494 read_persistent_clock64(&now);
1495 if (!timespec64_valid_strict(&now)) {
1496 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1497 " Check your CMOS/BIOS settings.\n");
1500 } else if (now.tv_sec || now.tv_nsec)
1501 persistent_clock_exists = true;
1503 read_boot_clock64(&boot);
1504 if (!timespec64_valid_strict(&boot)) {
1505 pr_warn("WARNING: Boot clock returned invalid value!\n"
1506 " Check your CMOS/BIOS settings.\n");
1511 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1512 write_seqcount_begin(&tk_core.seq);
1515 clock = clocksource_default_clock();
1517 clock->enable(clock);
1518 tk_setup_internals(tk, clock);
1520 tk_set_xtime(tk, &now);
1521 tk->raw_time.tv_sec = 0;
1522 tk->raw_time.tv_nsec = 0;
1523 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1524 boot = tk_xtime(tk);
1526 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1527 tk_set_wall_to_mono(tk, tmp);
1529 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1531 write_seqcount_end(&tk_core.seq);
1532 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1535 /* time in seconds when suspend began for persistent clock */
1536 static struct timespec64 timekeeping_suspend_time;
1539 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1540 * @delta: pointer to a timespec delta value
1542 * Takes a timespec offset measuring a suspend interval and properly
1543 * adds the sleep offset to the timekeeping variables.
1545 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1546 struct timespec64 *delta)
1548 if (!timespec64_valid_strict(delta)) {
1549 printk_deferred(KERN_WARNING
1550 "__timekeeping_inject_sleeptime: Invalid "
1551 "sleep delta value!\n");
1554 tk_xtime_add(tk, delta);
1555 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1556 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1557 tk_debug_account_sleep_time(delta);
1560 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1562 * We have three kinds of time sources to use for sleep time
1563 * injection, the preference order is:
1564 * 1) non-stop clocksource
1565 * 2) persistent clock (ie: RTC accessible when irqs are off)
1568 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1569 * If system has neither 1) nor 2), 3) will be used finally.
1572 * If timekeeping has injected sleeptime via either 1) or 2),
1573 * 3) becomes needless, so in this case we don't need to call
1574 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1577 bool timekeeping_rtc_skipresume(void)
1579 return sleeptime_injected;
1583 * 1) can be determined whether to use or not only when doing
1584 * timekeeping_resume() which is invoked after rtc_suspend(),
1585 * so we can't skip rtc_suspend() surely if system has 1).
1587 * But if system has 2), 2) will definitely be used, so in this
1588 * case we don't need to call rtc_suspend(), and this is what
1589 * timekeeping_rtc_skipsuspend() means.
1591 bool timekeeping_rtc_skipsuspend(void)
1593 return persistent_clock_exists;
1597 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1598 * @delta: pointer to a timespec64 delta value
1600 * This hook is for architectures that cannot support read_persistent_clock64
1601 * because their RTC/persistent clock is only accessible when irqs are enabled.
1602 * and also don't have an effective nonstop clocksource.
1604 * This function should only be called by rtc_resume(), and allows
1605 * a suspend offset to be injected into the timekeeping values.
1607 void timekeeping_inject_sleeptime64(struct timespec64 *delta)
1609 struct timekeeper *tk = &tk_core.timekeeper;
1610 unsigned long flags;
1612 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1613 write_seqcount_begin(&tk_core.seq);
1615 timekeeping_forward_now(tk);
1617 __timekeeping_inject_sleeptime(tk, delta);
1619 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1621 write_seqcount_end(&tk_core.seq);
1622 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1624 /* signal hrtimers about time change */
1630 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1632 void timekeeping_resume(void)
1634 struct timekeeper *tk = &tk_core.timekeeper;
1635 struct clocksource *clock = tk->tkr_mono.clock;
1636 unsigned long flags;
1637 struct timespec64 ts_new, ts_delta;
1638 cycle_t cycle_now, cycle_delta;
1640 sleeptime_injected = false;
1641 read_persistent_clock64(&ts_new);
1643 clockevents_resume();
1644 clocksource_resume();
1646 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1647 write_seqcount_begin(&tk_core.seq);
1650 * After system resumes, we need to calculate the suspended time and
1651 * compensate it for the OS time. There are 3 sources that could be
1652 * used: Nonstop clocksource during suspend, persistent clock and rtc
1655 * One specific platform may have 1 or 2 or all of them, and the
1656 * preference will be:
1657 * suspend-nonstop clocksource -> persistent clock -> rtc
1658 * The less preferred source will only be tried if there is no better
1659 * usable source. The rtc part is handled separately in rtc core code.
1661 cycle_now = tk_clock_read(&tk->tkr_mono);
1662 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1663 cycle_now > tk->tkr_mono.cycle_last) {
1664 u64 num, max = ULLONG_MAX;
1665 u32 mult = clock->mult;
1666 u32 shift = clock->shift;
1669 cycle_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
1673 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1674 * suspended time is too long. In that case we need do the
1675 * 64 bits math carefully
1678 if (cycle_delta > max) {
1679 num = div64_u64(cycle_delta, max);
1680 nsec = (((u64) max * mult) >> shift) * num;
1681 cycle_delta -= num * max;
1683 nsec += ((u64) cycle_delta * mult) >> shift;
1685 ts_delta = ns_to_timespec64(nsec);
1686 sleeptime_injected = true;
1687 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1688 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1689 sleeptime_injected = true;
1692 if (sleeptime_injected)
1693 __timekeeping_inject_sleeptime(tk, &ts_delta);
1695 /* Re-base the last cycle value */
1696 tk->tkr_mono.cycle_last = cycle_now;
1697 tk->tkr_raw.cycle_last = cycle_now;
1700 timekeeping_suspended = 0;
1701 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1702 write_seqcount_end(&tk_core.seq);
1703 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1705 touch_softlockup_watchdog();
1711 int timekeeping_suspend(void)
1713 struct timekeeper *tk = &tk_core.timekeeper;
1714 unsigned long flags;
1715 struct timespec64 delta, delta_delta;
1716 static struct timespec64 old_delta;
1718 read_persistent_clock64(&timekeeping_suspend_time);
1721 * On some systems the persistent_clock can not be detected at
1722 * timekeeping_init by its return value, so if we see a valid
1723 * value returned, update the persistent_clock_exists flag.
1725 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1726 persistent_clock_exists = true;
1728 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1729 write_seqcount_begin(&tk_core.seq);
1730 timekeeping_forward_now(tk);
1731 timekeeping_suspended = 1;
1733 if (persistent_clock_exists) {
1735 * To avoid drift caused by repeated suspend/resumes,
1736 * which each can add ~1 second drift error,
1737 * try to compensate so the difference in system time
1738 * and persistent_clock time stays close to constant.
1740 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1741 delta_delta = timespec64_sub(delta, old_delta);
1742 if (abs(delta_delta.tv_sec) >= 2) {
1744 * if delta_delta is too large, assume time correction
1745 * has occurred and set old_delta to the current delta.
1749 /* Otherwise try to adjust old_system to compensate */
1750 timekeeping_suspend_time =
1751 timespec64_add(timekeeping_suspend_time, delta_delta);
1755 timekeeping_update(tk, TK_MIRROR);
1756 halt_fast_timekeeper(tk);
1757 write_seqcount_end(&tk_core.seq);
1758 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1761 clocksource_suspend();
1762 clockevents_suspend();
1767 /* sysfs resume/suspend bits for timekeeping */
1768 static struct syscore_ops timekeeping_syscore_ops = {
1769 .resume = timekeeping_resume,
1770 .suspend = timekeeping_suspend,
1773 static int __init timekeeping_init_ops(void)
1775 register_syscore_ops(&timekeeping_syscore_ops);
1778 device_initcall(timekeeping_init_ops);
1781 * Apply a multiplier adjustment to the timekeeper
1783 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1788 s64 interval = tk->cycle_interval;
1792 mult_adj = -mult_adj;
1793 interval = -interval;
1796 mult_adj <<= adj_scale;
1797 interval <<= adj_scale;
1798 offset <<= adj_scale;
1801 * So the following can be confusing.
1803 * To keep things simple, lets assume mult_adj == 1 for now.
1805 * When mult_adj != 1, remember that the interval and offset values
1806 * have been appropriately scaled so the math is the same.
1808 * The basic idea here is that we're increasing the multiplier
1809 * by one, this causes the xtime_interval to be incremented by
1810 * one cycle_interval. This is because:
1811 * xtime_interval = cycle_interval * mult
1812 * So if mult is being incremented by one:
1813 * xtime_interval = cycle_interval * (mult + 1)
1815 * xtime_interval = (cycle_interval * mult) + cycle_interval
1816 * Which can be shortened to:
1817 * xtime_interval += cycle_interval
1819 * So offset stores the non-accumulated cycles. Thus the current
1820 * time (in shifted nanoseconds) is:
1821 * now = (offset * adj) + xtime_nsec
1822 * Now, even though we're adjusting the clock frequency, we have
1823 * to keep time consistent. In other words, we can't jump back
1824 * in time, and we also want to avoid jumping forward in time.
1826 * So given the same offset value, we need the time to be the same
1827 * both before and after the freq adjustment.
1828 * now = (offset * adj_1) + xtime_nsec_1
1829 * now = (offset * adj_2) + xtime_nsec_2
1831 * (offset * adj_1) + xtime_nsec_1 =
1832 * (offset * adj_2) + xtime_nsec_2
1836 * (offset * adj_1) + xtime_nsec_1 =
1837 * (offset * (adj_1+1)) + xtime_nsec_2
1838 * (offset * adj_1) + xtime_nsec_1 =
1839 * (offset * adj_1) + offset + xtime_nsec_2
1840 * Canceling the sides:
1841 * xtime_nsec_1 = offset + xtime_nsec_2
1843 * xtime_nsec_2 = xtime_nsec_1 - offset
1844 * Which simplfies to:
1845 * xtime_nsec -= offset
1847 * XXX - TODO: Doc ntp_error calculation.
1849 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1850 /* NTP adjustment caused clocksource mult overflow */
1855 tk->tkr_mono.mult += mult_adj;
1856 tk->xtime_interval += interval;
1857 tk->tkr_mono.xtime_nsec -= offset;
1858 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1862 * Calculate the multiplier adjustment needed to match the frequency
1865 static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
1868 s64 interval = tk->cycle_interval;
1869 s64 xinterval = tk->xtime_interval;
1870 u32 base = tk->tkr_mono.clock->mult;
1871 u32 max = tk->tkr_mono.clock->maxadj;
1872 u32 cur_adj = tk->tkr_mono.mult;
1877 /* Remove any current error adj from freq calculation */
1878 if (tk->ntp_err_mult)
1879 xinterval -= tk->cycle_interval;
1881 tk->ntp_tick = ntp_tick_length();
1883 /* Calculate current error per tick */
1884 tick_error = ntp_tick_length() >> tk->ntp_error_shift;
1885 tick_error -= (xinterval + tk->xtime_remainder);
1887 /* Don't worry about correcting it if its small */
1888 if (likely((tick_error >= 0) && (tick_error <= interval)))
1891 /* preserve the direction of correction */
1892 negative = (tick_error < 0);
1894 /* If any adjustment would pass the max, just return */
1895 if (negative && (cur_adj - 1) <= (base - max))
1897 if (!negative && (cur_adj + 1) >= (base + max))
1900 * Sort out the magnitude of the correction, but
1901 * avoid making so large a correction that we go
1902 * over the max adjustment.
1905 tick_error = abs(tick_error);
1906 while (tick_error > interval) {
1907 u32 adj = 1 << (adj_scale + 1);
1909 /* Check if adjustment gets us within 1 unit from the max */
1910 if (negative && (cur_adj - adj) <= (base - max))
1912 if (!negative && (cur_adj + adj) >= (base + max))
1919 /* scale the corrections */
1920 timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
1924 * Adjust the timekeeper's multiplier to the correct frequency
1925 * and also to reduce the accumulated error value.
1927 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1929 /* Correct for the current frequency error */
1930 timekeeping_freqadjust(tk, offset);
1932 /* Next make a small adjustment to fix any cumulative error */
1933 if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
1934 tk->ntp_err_mult = 1;
1935 timekeeping_apply_adjustment(tk, offset, 0, 0);
1936 } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
1937 /* Undo any existing error adjustment */
1938 timekeeping_apply_adjustment(tk, offset, 1, 0);
1939 tk->ntp_err_mult = 0;
1942 if (unlikely(tk->tkr_mono.clock->maxadj &&
1943 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1944 > tk->tkr_mono.clock->maxadj))) {
1945 printk_once(KERN_WARNING
1946 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1947 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1948 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1952 * It may be possible that when we entered this function, xtime_nsec
1953 * was very small. Further, if we're slightly speeding the clocksource
1954 * in the code above, its possible the required corrective factor to
1955 * xtime_nsec could cause it to underflow.
1957 * Now, since we already accumulated the second, cannot simply roll
1958 * the accumulated second back, since the NTP subsystem has been
1959 * notified via second_overflow. So instead we push xtime_nsec forward
1960 * by the amount we underflowed, and add that amount into the error.
1962 * We'll correct this error next time through this function, when
1963 * xtime_nsec is not as small.
1965 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1966 s64 neg = -(s64)tk->tkr_mono.xtime_nsec;
1967 tk->tkr_mono.xtime_nsec = 0;
1968 tk->ntp_error += neg << tk->ntp_error_shift;
1973 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1975 * Helper function that accumulates the nsecs greater than a second
1976 * from the xtime_nsec field to the xtime_secs field.
1977 * It also calls into the NTP code to handle leapsecond processing.
1980 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1982 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1983 unsigned int clock_set = 0;
1985 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1988 tk->tkr_mono.xtime_nsec -= nsecps;
1991 /* Figure out if its a leap sec and apply if needed */
1992 leap = second_overflow(tk->xtime_sec);
1993 if (unlikely(leap)) {
1994 struct timespec64 ts;
1996 tk->xtime_sec += leap;
2000 tk_set_wall_to_mono(tk,
2001 timespec64_sub(tk->wall_to_monotonic, ts));
2003 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
2005 clock_set = TK_CLOCK_WAS_SET;
2012 * logarithmic_accumulation - shifted accumulation of cycles
2014 * This functions accumulates a shifted interval of cycles into
2015 * into a shifted interval nanoseconds. Allows for O(log) accumulation
2018 * Returns the unconsumed cycles.
2020 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
2022 unsigned int *clock_set)
2024 cycle_t interval = tk->cycle_interval << shift;
2027 /* If the offset is smaller than a shifted interval, do nothing */
2028 if (offset < interval)
2031 /* Accumulate one shifted interval */
2033 tk->tkr_mono.cycle_last += interval;
2034 tk->tkr_raw.cycle_last += interval;
2036 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2037 *clock_set |= accumulate_nsecs_to_secs(tk);
2039 /* Accumulate raw time */
2040 tk->tkr_raw.xtime_nsec += (u64)tk->raw_time.tv_nsec << tk->tkr_raw.shift;
2041 tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2042 snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2043 while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2044 tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2045 tk->raw_time.tv_sec++;
2047 tk->raw_time.tv_nsec = tk->tkr_raw.xtime_nsec >> tk->tkr_raw.shift;
2048 tk->tkr_raw.xtime_nsec -= (u64)tk->raw_time.tv_nsec << tk->tkr_raw.shift;
2050 /* Accumulate error between NTP and clock interval */
2051 tk->ntp_error += tk->ntp_tick << shift;
2052 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2053 (tk->ntp_error_shift + shift);
2059 * update_wall_time - Uses the current clocksource to increment the wall time
2062 void update_wall_time(void)
2064 struct timekeeper *real_tk = &tk_core.timekeeper;
2065 struct timekeeper *tk = &shadow_timekeeper;
2067 int shift = 0, maxshift;
2068 unsigned int clock_set = 0;
2069 unsigned long flags;
2071 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2073 /* Make sure we're fully resumed: */
2074 if (unlikely(timekeeping_suspended))
2077 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2078 offset = real_tk->cycle_interval;
2080 offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2081 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2084 /* Check if there's really nothing to do */
2085 if (offset < real_tk->cycle_interval)
2088 /* Do some additional sanity checking */
2089 timekeeping_check_update(real_tk, offset);
2092 * With NO_HZ we may have to accumulate many cycle_intervals
2093 * (think "ticks") worth of time at once. To do this efficiently,
2094 * we calculate the largest doubling multiple of cycle_intervals
2095 * that is smaller than the offset. We then accumulate that
2096 * chunk in one go, and then try to consume the next smaller
2099 shift = ilog2(offset) - ilog2(tk->cycle_interval);
2100 shift = max(0, shift);
2101 /* Bound shift to one less than what overflows tick_length */
2102 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2103 shift = min(shift, maxshift);
2104 while (offset >= tk->cycle_interval) {
2105 offset = logarithmic_accumulation(tk, offset, shift,
2107 if (offset < tk->cycle_interval<<shift)
2111 /* correct the clock when NTP error is too big */
2112 timekeeping_adjust(tk, offset);
2115 * XXX This can be killed once everyone converts
2116 * to the new update_vsyscall.
2118 old_vsyscall_fixup(tk);
2121 * Finally, make sure that after the rounding
2122 * xtime_nsec isn't larger than NSEC_PER_SEC
2124 clock_set |= accumulate_nsecs_to_secs(tk);
2126 write_seqcount_begin(&tk_core.seq);
2128 * Update the real timekeeper.
2130 * We could avoid this memcpy by switching pointers, but that
2131 * requires changes to all other timekeeper usage sites as
2132 * well, i.e. move the timekeeper pointer getter into the
2133 * spinlocked/seqcount protected sections. And we trade this
2134 * memcpy under the tk_core.seq against one before we start
2137 timekeeping_update(tk, clock_set);
2138 memcpy(real_tk, tk, sizeof(*tk));
2139 /* The memcpy must come last. Do not put anything here! */
2140 write_seqcount_end(&tk_core.seq);
2142 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2144 /* Have to call _delayed version, since in irq context*/
2145 clock_was_set_delayed();
2149 * getboottime64 - Return the real time of system boot.
2150 * @ts: pointer to the timespec64 to be set
2152 * Returns the wall-time of boot in a timespec64.
2154 * This is based on the wall_to_monotonic offset and the total suspend
2155 * time. Calls to settimeofday will affect the value returned (which
2156 * basically means that however wrong your real time clock is at boot time,
2157 * you get the right time here).
2159 void getboottime64(struct timespec64 *ts)
2161 struct timekeeper *tk = &tk_core.timekeeper;
2162 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2164 *ts = ktime_to_timespec64(t);
2166 EXPORT_SYMBOL_GPL(getboottime64);
2168 unsigned long get_seconds(void)
2170 struct timekeeper *tk = &tk_core.timekeeper;
2172 return tk->xtime_sec;
2174 EXPORT_SYMBOL(get_seconds);
2176 struct timespec __current_kernel_time(void)
2178 struct timekeeper *tk = &tk_core.timekeeper;
2180 return timespec64_to_timespec(tk_xtime(tk));
2183 struct timespec64 current_kernel_time64(void)
2185 struct timekeeper *tk = &tk_core.timekeeper;
2186 struct timespec64 now;
2190 seq = read_seqcount_begin(&tk_core.seq);
2193 } while (read_seqcount_retry(&tk_core.seq, seq));
2197 EXPORT_SYMBOL(current_kernel_time64);
2199 struct timespec64 get_monotonic_coarse64(void)
2201 struct timekeeper *tk = &tk_core.timekeeper;
2202 struct timespec64 now, mono;
2206 seq = read_seqcount_begin(&tk_core.seq);
2209 mono = tk->wall_to_monotonic;
2210 } while (read_seqcount_retry(&tk_core.seq, seq));
2212 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
2213 now.tv_nsec + mono.tv_nsec);
2217 EXPORT_SYMBOL(get_monotonic_coarse64);
2220 * Must hold jiffies_lock
2222 void do_timer(unsigned long ticks)
2224 jiffies_64 += ticks;
2225 calc_global_load(ticks);
2229 * ktime_get_update_offsets_now - hrtimer helper
2230 * @cwsseq: pointer to check and store the clock was set sequence number
2231 * @offs_real: pointer to storage for monotonic -> realtime offset
2232 * @offs_boot: pointer to storage for monotonic -> boottime offset
2233 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2235 * Returns current monotonic time and updates the offsets if the
2236 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2239 * Called from hrtimer_interrupt() or retrigger_next_event()
2241 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2242 ktime_t *offs_boot, ktime_t *offs_tai)
2244 struct timekeeper *tk = &tk_core.timekeeper;
2250 seq = read_seqcount_begin(&tk_core.seq);
2252 base = tk->tkr_mono.base;
2253 nsecs = timekeeping_get_ns(&tk->tkr_mono);
2254 base = ktime_add_ns(base, nsecs);
2256 if (*cwsseq != tk->clock_was_set_seq) {
2257 *cwsseq = tk->clock_was_set_seq;
2258 *offs_real = tk->offs_real;
2259 *offs_boot = tk->offs_boot;
2260 *offs_tai = tk->offs_tai;
2263 /* Handle leapsecond insertion adjustments */
2264 if (unlikely(base.tv64 >= tk->next_leap_ktime.tv64))
2265 *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2267 } while (read_seqcount_retry(&tk_core.seq, seq));
2273 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2275 int do_adjtimex(struct timex *txc)
2277 struct timekeeper *tk = &tk_core.timekeeper;
2278 unsigned long flags;
2279 struct timespec64 ts;
2283 /* Validate the data before disabling interrupts */
2284 ret = ntp_validate_timex(txc);
2288 if (txc->modes & ADJ_SETOFFSET) {
2289 struct timespec delta;
2290 delta.tv_sec = txc->time.tv_sec;
2291 delta.tv_nsec = txc->time.tv_usec;
2292 if (!(txc->modes & ADJ_NANO))
2293 delta.tv_nsec *= 1000;
2294 ret = timekeeping_inject_offset(&delta);
2299 getnstimeofday64(&ts);
2301 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2302 write_seqcount_begin(&tk_core.seq);
2304 orig_tai = tai = tk->tai_offset;
2305 ret = __do_adjtimex(txc, &ts, &tai);
2307 if (tai != orig_tai) {
2308 __timekeeping_set_tai_offset(tk, tai);
2309 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2311 tk_update_leap_state(tk);
2313 write_seqcount_end(&tk_core.seq);
2314 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2316 if (tai != orig_tai)
2319 ntp_notify_cmos_timer();
2324 #ifdef CONFIG_NTP_PPS
2326 * hardpps() - Accessor function to NTP __hardpps function
2328 void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2330 unsigned long flags;
2332 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2333 write_seqcount_begin(&tk_core.seq);
2335 __hardpps(phase_ts, raw_ts);
2337 write_seqcount_end(&tk_core.seq);
2338 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2340 EXPORT_SYMBOL(hardpps);
2344 * xtime_update() - advances the timekeeping infrastructure
2345 * @ticks: number of ticks, that have elapsed since the last call.
2347 * Must be called with interrupts disabled.
2349 void xtime_update(unsigned long ticks)
2351 write_seqlock(&jiffies_lock);
2353 write_sequnlock(&jiffies_lock);