2 * linux/kernel/time/timekeeping.c
4 * Kernel timekeeping code and accessor functions
6 * This code was moved from linux/kernel/timer.c.
7 * Please see that file for copyright and history logs.
11 #include <linux/timekeeper_internal.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include <linux/percpu.h>
15 #include <linux/init.h>
17 #include <linux/sched.h>
18 #include <linux/syscore_ops.h>
19 #include <linux/clocksource.h>
20 #include <linux/jiffies.h>
21 #include <linux/time.h>
22 #include <linux/tick.h>
23 #include <linux/stop_machine.h>
24 #include <linux/pvclock_gtod.h>
25 #include <linux/compiler.h>
27 #include "tick-internal.h"
28 #include "ntp_internal.h"
29 #include "timekeeping_internal.h"
31 #define TK_CLEAR_NTP (1 << 0)
32 #define TK_MIRROR (1 << 1)
33 #define TK_CLOCK_WAS_SET (1 << 2)
36 * The most important data for readout fits into a single 64 byte
41 struct timekeeper timekeeper;
42 } tk_core ____cacheline_aligned;
44 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
45 static struct timekeeper shadow_timekeeper;
48 * struct tk_fast - NMI safe timekeeper
49 * @seq: Sequence counter for protecting updates. The lowest bit
50 * is the index for the tk_read_base array
51 * @base: tk_read_base array. Access is indexed by the lowest bit of
54 * See @update_fast_timekeeper() below.
58 struct tk_read_base base[2];
61 static struct tk_fast tk_fast_mono ____cacheline_aligned;
62 static struct tk_fast tk_fast_raw ____cacheline_aligned;
64 /* flag for if timekeeping is suspended */
65 int __read_mostly timekeeping_suspended;
67 static inline void tk_normalize_xtime(struct timekeeper *tk)
69 while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
70 tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
75 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
79 ts.tv_sec = tk->xtime_sec;
80 ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
84 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
86 tk->xtime_sec = ts->tv_sec;
87 tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
90 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
92 tk->xtime_sec += ts->tv_sec;
93 tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
94 tk_normalize_xtime(tk);
97 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
99 struct timespec64 tmp;
102 * Verify consistency of: offset_real = -wall_to_monotonic
103 * before modifying anything
105 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
106 -tk->wall_to_monotonic.tv_nsec);
107 WARN_ON_ONCE(tk->offs_real.tv64 != timespec64_to_ktime(tmp).tv64);
108 tk->wall_to_monotonic = wtm;
109 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
110 tk->offs_real = timespec64_to_ktime(tmp);
111 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
114 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
116 tk->offs_boot = ktime_add(tk->offs_boot, delta);
119 #ifdef CONFIG_DEBUG_TIMEKEEPING
120 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
122 static void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
125 cycle_t max_cycles = tk->tkr_mono.clock->max_cycles;
126 const char *name = tk->tkr_mono.clock->name;
128 if (offset > max_cycles) {
129 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
130 offset, name, max_cycles);
131 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
133 if (offset > (max_cycles >> 1)) {
134 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
135 offset, name, max_cycles >> 1);
136 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
140 if (tk->underflow_seen) {
141 if (jiffies - tk->last_warning > WARNING_FREQ) {
142 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
143 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
144 printk_deferred(" Your kernel is probably still fine.\n");
145 tk->last_warning = jiffies;
147 tk->underflow_seen = 0;
150 if (tk->overflow_seen) {
151 if (jiffies - tk->last_warning > WARNING_FREQ) {
152 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
153 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
154 printk_deferred(" Your kernel is probably still fine.\n");
155 tk->last_warning = jiffies;
157 tk->overflow_seen = 0;
161 static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
163 struct timekeeper *tk = &tk_core.timekeeper;
164 cycle_t now, last, mask, max, delta;
168 * Since we're called holding a seqlock, the data may shift
169 * under us while we're doing the calculation. This can cause
170 * false positives, since we'd note a problem but throw the
171 * results away. So nest another seqlock here to atomically
172 * grab the points we are checking with.
175 seq = read_seqcount_begin(&tk_core.seq);
176 now = tkr->read(tkr->clock);
177 last = tkr->cycle_last;
179 max = tkr->clock->max_cycles;
180 } while (read_seqcount_retry(&tk_core.seq, seq));
182 delta = clocksource_delta(now, last, mask);
185 * Try to catch underflows by checking if we are seeing small
186 * mask-relative negative values.
188 if (unlikely((~delta & mask) < (mask >> 3))) {
189 tk->underflow_seen = 1;
193 /* Cap delta value to the max_cycles values to avoid mult overflows */
194 if (unlikely(delta > max)) {
195 tk->overflow_seen = 1;
196 delta = tkr->clock->max_cycles;
202 static inline void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
205 static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
207 cycle_t cycle_now, delta;
209 /* read clocksource */
210 cycle_now = tkr->read(tkr->clock);
212 /* calculate the delta since the last update_wall_time */
213 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
220 * tk_setup_internals - Set up internals to use clocksource clock.
222 * @tk: The target timekeeper to setup.
223 * @clock: Pointer to clocksource.
225 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
226 * pair and interval request.
228 * Unless you're the timekeeping code, you should not be using this!
230 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
233 u64 tmp, ntpinterval;
234 struct clocksource *old_clock;
236 ++tk->cs_was_changed_seq;
237 old_clock = tk->tkr_mono.clock;
238 tk->tkr_mono.clock = clock;
239 tk->tkr_mono.read = clock->read;
240 tk->tkr_mono.mask = clock->mask;
241 tk->tkr_mono.cycle_last = tk->tkr_mono.read(clock);
243 tk->tkr_raw.clock = clock;
244 tk->tkr_raw.read = clock->read;
245 tk->tkr_raw.mask = clock->mask;
246 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
248 /* Do the ns -> cycle conversion first, using original mult */
249 tmp = NTP_INTERVAL_LENGTH;
250 tmp <<= clock->shift;
252 tmp += clock->mult/2;
253 do_div(tmp, clock->mult);
257 interval = (cycle_t) tmp;
258 tk->cycle_interval = interval;
260 /* Go back from cycles -> shifted ns */
261 tk->xtime_interval = interval * clock->mult;
262 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
263 tk->raw_interval = (interval * clock->mult) >> clock->shift;
265 /* if changing clocks, convert xtime_nsec shift units */
267 int shift_change = clock->shift - old_clock->shift;
268 if (shift_change < 0)
269 tk->tkr_mono.xtime_nsec >>= -shift_change;
271 tk->tkr_mono.xtime_nsec <<= shift_change;
273 tk->tkr_raw.xtime_nsec = 0;
275 tk->tkr_mono.shift = clock->shift;
276 tk->tkr_raw.shift = clock->shift;
279 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
280 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
283 * The timekeeper keeps its own mult values for the currently
284 * active clocksource. These value will be adjusted via NTP
285 * to counteract clock drifting.
287 tk->tkr_mono.mult = clock->mult;
288 tk->tkr_raw.mult = clock->mult;
289 tk->ntp_err_mult = 0;
292 /* Timekeeper helper functions. */
294 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
295 static u32 default_arch_gettimeoffset(void) { return 0; }
296 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
298 static inline u32 arch_gettimeoffset(void) { return 0; }
301 static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr,
306 nsec = delta * tkr->mult + tkr->xtime_nsec;
309 /* If arch requires, add in get_arch_timeoffset() */
310 return nsec + arch_gettimeoffset();
313 static inline u64 timekeeping_get_ns(struct tk_read_base *tkr)
317 delta = timekeeping_get_delta(tkr);
318 return timekeeping_delta_to_ns(tkr, delta);
321 static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
326 /* calculate the delta since the last update_wall_time */
327 delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
328 return timekeeping_delta_to_ns(tkr, delta);
332 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
333 * @tkr: Timekeeping readout base from which we take the update
335 * We want to use this from any context including NMI and tracing /
336 * instrumenting the timekeeping code itself.
338 * Employ the latch technique; see @raw_write_seqcount_latch.
340 * So if a NMI hits the update of base[0] then it will use base[1]
341 * which is still consistent. In the worst case this can result is a
342 * slightly wrong timestamp (a few nanoseconds). See
343 * @ktime_get_mono_fast_ns.
345 static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
347 struct tk_read_base *base = tkf->base;
349 /* Force readers off to base[1] */
350 raw_write_seqcount_latch(&tkf->seq);
353 memcpy(base, tkr, sizeof(*base));
355 /* Force readers back to base[0] */
356 raw_write_seqcount_latch(&tkf->seq);
359 memcpy(base + 1, base, sizeof(*base));
363 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
365 * This timestamp is not guaranteed to be monotonic across an update.
366 * The timestamp is calculated by:
368 * now = base_mono + clock_delta * slope
370 * So if the update lowers the slope, readers who are forced to the
371 * not yet updated second array are still using the old steeper slope.
380 * |12345678---> reader order
386 * So reader 6 will observe time going backwards versus reader 5.
388 * While other CPUs are likely to be able observe that, the only way
389 * for a CPU local observation is when an NMI hits in the middle of
390 * the update. Timestamps taken from that NMI context might be ahead
391 * of the following timestamps. Callers need to be aware of that and
394 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
396 struct tk_read_base *tkr;
401 seq = raw_read_seqcount_latch(&tkf->seq);
402 tkr = tkf->base + (seq & 0x01);
403 now = ktime_to_ns(tkr->base);
405 now += timekeeping_delta_to_ns(tkr,
407 tkr->read(tkr->clock),
410 } while (read_seqcount_retry(&tkf->seq, seq));
415 u64 ktime_get_mono_fast_ns(void)
417 return __ktime_get_fast_ns(&tk_fast_mono);
419 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
421 u64 ktime_get_raw_fast_ns(void)
423 return __ktime_get_fast_ns(&tk_fast_raw);
425 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
428 * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
430 * To keep it NMI safe since we're accessing from tracing, we're not using a
431 * separate timekeeper with updates to monotonic clock and boot offset
432 * protected with seqlocks. This has the following minor side effects:
434 * (1) Its possible that a timestamp be taken after the boot offset is updated
435 * but before the timekeeper is updated. If this happens, the new boot offset
436 * is added to the old timekeeping making the clock appear to update slightly
439 * timekeeping_inject_sleeptime64()
440 * __timekeeping_inject_sleeptime(tk, delta);
442 * timekeeping_update(tk, TK_CLEAR_NTP...);
444 * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
445 * partially updated. Since the tk->offs_boot update is a rare event, this
446 * should be a rare occurrence which postprocessing should be able to handle.
448 u64 notrace ktime_get_boot_fast_ns(void)
450 struct timekeeper *tk = &tk_core.timekeeper;
452 return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
454 EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
456 /* Suspend-time cycles value for halted fast timekeeper. */
457 static cycle_t cycles_at_suspend;
459 static cycle_t dummy_clock_read(struct clocksource *cs)
461 return cycles_at_suspend;
465 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
466 * @tk: Timekeeper to snapshot.
468 * It generally is unsafe to access the clocksource after timekeeping has been
469 * suspended, so take a snapshot of the readout base of @tk and use it as the
470 * fast timekeeper's readout base while suspended. It will return the same
471 * number of cycles every time until timekeeping is resumed at which time the
472 * proper readout base for the fast timekeeper will be restored automatically.
474 static void halt_fast_timekeeper(struct timekeeper *tk)
476 static struct tk_read_base tkr_dummy;
477 struct tk_read_base *tkr = &tk->tkr_mono;
479 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
480 cycles_at_suspend = tkr->read(tkr->clock);
481 tkr_dummy.read = dummy_clock_read;
482 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
485 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
486 tkr_dummy.read = dummy_clock_read;
487 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
490 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
492 static inline void update_vsyscall(struct timekeeper *tk)
494 struct timespec xt, wm;
496 xt = timespec64_to_timespec(tk_xtime(tk));
497 wm = timespec64_to_timespec(tk->wall_to_monotonic);
498 update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult,
499 tk->tkr_mono.cycle_last);
502 static inline void old_vsyscall_fixup(struct timekeeper *tk)
507 * Store only full nanoseconds into xtime_nsec after rounding
508 * it up and add the remainder to the error difference.
509 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
510 * by truncating the remainder in vsyscalls. However, it causes
511 * additional work to be done in timekeeping_adjust(). Once
512 * the vsyscall implementations are converted to use xtime_nsec
513 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
514 * users are removed, this can be killed.
516 remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1);
517 if (remainder != 0) {
518 tk->tkr_mono.xtime_nsec -= remainder;
519 tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift;
520 tk->ntp_error += remainder << tk->ntp_error_shift;
521 tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift;
525 #define old_vsyscall_fixup(tk)
528 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
530 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
532 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
536 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
538 int pvclock_gtod_register_notifier(struct notifier_block *nb)
540 struct timekeeper *tk = &tk_core.timekeeper;
544 raw_spin_lock_irqsave(&timekeeper_lock, flags);
545 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
546 update_pvclock_gtod(tk, true);
547 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
551 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
554 * pvclock_gtod_unregister_notifier - unregister a pvclock
555 * timedata update listener
557 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
562 raw_spin_lock_irqsave(&timekeeper_lock, flags);
563 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
564 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
568 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
571 * tk_update_leap_state - helper to update the next_leap_ktime
573 static inline void tk_update_leap_state(struct timekeeper *tk)
575 tk->next_leap_ktime = ntp_get_next_leap();
576 if (tk->next_leap_ktime.tv64 != KTIME_MAX)
577 /* Convert to monotonic time */
578 tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
582 * Update the ktime_t based scalar nsec members of the timekeeper
584 static inline void tk_update_ktime_data(struct timekeeper *tk)
590 * The xtime based monotonic readout is:
591 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
592 * The ktime based monotonic readout is:
593 * nsec = base_mono + now();
594 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
596 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
597 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
598 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
600 /* Update the monotonic raw base */
601 tk->tkr_raw.base = timespec64_to_ktime(tk->raw_time);
604 * The sum of the nanoseconds portions of xtime and
605 * wall_to_monotonic can be greater/equal one second. Take
606 * this into account before updating tk->ktime_sec.
608 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
609 if (nsec >= NSEC_PER_SEC)
611 tk->ktime_sec = seconds;
614 /* must hold timekeeper_lock */
615 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
617 if (action & TK_CLEAR_NTP) {
622 tk_update_leap_state(tk);
623 tk_update_ktime_data(tk);
626 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
628 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
629 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
631 if (action & TK_CLOCK_WAS_SET)
632 tk->clock_was_set_seq++;
634 * The mirroring of the data to the shadow-timekeeper needs
635 * to happen last here to ensure we don't over-write the
636 * timekeeper structure on the next update with stale data
638 if (action & TK_MIRROR)
639 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
640 sizeof(tk_core.timekeeper));
644 * timekeeping_forward_now - update clock to the current time
646 * Forward the current clock to update its state since the last call to
647 * update_wall_time(). This is useful before significant clock changes,
648 * as it avoids having to deal with this time offset explicitly.
650 static void timekeeping_forward_now(struct timekeeper *tk)
652 struct clocksource *clock = tk->tkr_mono.clock;
653 cycle_t cycle_now, delta;
656 cycle_now = tk->tkr_mono.read(clock);
657 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
658 tk->tkr_mono.cycle_last = cycle_now;
659 tk->tkr_raw.cycle_last = cycle_now;
661 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
663 /* If arch requires, add in get_arch_timeoffset() */
664 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
666 tk_normalize_xtime(tk);
668 nsec = clocksource_cyc2ns(delta, tk->tkr_raw.mult, tk->tkr_raw.shift);
669 timespec64_add_ns(&tk->raw_time, nsec);
673 * __getnstimeofday64 - Returns the time of day in a timespec64.
674 * @ts: pointer to the timespec to be set
676 * Updates the time of day in the timespec.
677 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
679 int __getnstimeofday64(struct timespec64 *ts)
681 struct timekeeper *tk = &tk_core.timekeeper;
686 seq = read_seqcount_begin(&tk_core.seq);
688 ts->tv_sec = tk->xtime_sec;
689 nsecs = timekeeping_get_ns(&tk->tkr_mono);
691 } while (read_seqcount_retry(&tk_core.seq, seq));
694 timespec64_add_ns(ts, nsecs);
697 * Do not bail out early, in case there were callers still using
698 * the value, even in the face of the WARN_ON.
700 if (unlikely(timekeeping_suspended))
704 EXPORT_SYMBOL(__getnstimeofday64);
707 * getnstimeofday64 - Returns the time of day in a timespec64.
708 * @ts: pointer to the timespec64 to be set
710 * Returns the time of day in a timespec64 (WARN if suspended).
712 void getnstimeofday64(struct timespec64 *ts)
714 WARN_ON(__getnstimeofday64(ts));
716 EXPORT_SYMBOL(getnstimeofday64);
718 ktime_t ktime_get(void)
720 struct timekeeper *tk = &tk_core.timekeeper;
725 WARN_ON(timekeeping_suspended);
728 seq = read_seqcount_begin(&tk_core.seq);
729 base = tk->tkr_mono.base;
730 nsecs = timekeeping_get_ns(&tk->tkr_mono);
732 } while (read_seqcount_retry(&tk_core.seq, seq));
734 return ktime_add_ns(base, nsecs);
736 EXPORT_SYMBOL_GPL(ktime_get);
738 u32 ktime_get_resolution_ns(void)
740 struct timekeeper *tk = &tk_core.timekeeper;
744 WARN_ON(timekeeping_suspended);
747 seq = read_seqcount_begin(&tk_core.seq);
748 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
749 } while (read_seqcount_retry(&tk_core.seq, seq));
753 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
755 static ktime_t *offsets[TK_OFFS_MAX] = {
756 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
757 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
758 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
761 ktime_t ktime_get_with_offset(enum tk_offsets offs)
763 struct timekeeper *tk = &tk_core.timekeeper;
765 ktime_t base, *offset = offsets[offs];
768 WARN_ON(timekeeping_suspended);
771 seq = read_seqcount_begin(&tk_core.seq);
772 base = ktime_add(tk->tkr_mono.base, *offset);
773 nsecs = timekeeping_get_ns(&tk->tkr_mono);
775 } while (read_seqcount_retry(&tk_core.seq, seq));
777 return ktime_add_ns(base, nsecs);
780 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
783 * ktime_mono_to_any() - convert mononotic time to any other time
784 * @tmono: time to convert.
785 * @offs: which offset to use
787 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
789 ktime_t *offset = offsets[offs];
794 seq = read_seqcount_begin(&tk_core.seq);
795 tconv = ktime_add(tmono, *offset);
796 } while (read_seqcount_retry(&tk_core.seq, seq));
800 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
803 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
805 ktime_t ktime_get_raw(void)
807 struct timekeeper *tk = &tk_core.timekeeper;
813 seq = read_seqcount_begin(&tk_core.seq);
814 base = tk->tkr_raw.base;
815 nsecs = timekeeping_get_ns(&tk->tkr_raw);
817 } while (read_seqcount_retry(&tk_core.seq, seq));
819 return ktime_add_ns(base, nsecs);
821 EXPORT_SYMBOL_GPL(ktime_get_raw);
824 * ktime_get_ts64 - get the monotonic clock in timespec64 format
825 * @ts: pointer to timespec variable
827 * The function calculates the monotonic clock from the realtime
828 * clock and the wall_to_monotonic offset and stores the result
829 * in normalized timespec64 format in the variable pointed to by @ts.
831 void ktime_get_ts64(struct timespec64 *ts)
833 struct timekeeper *tk = &tk_core.timekeeper;
834 struct timespec64 tomono;
838 WARN_ON(timekeeping_suspended);
841 seq = read_seqcount_begin(&tk_core.seq);
842 ts->tv_sec = tk->xtime_sec;
843 nsec = timekeeping_get_ns(&tk->tkr_mono);
844 tomono = tk->wall_to_monotonic;
846 } while (read_seqcount_retry(&tk_core.seq, seq));
848 ts->tv_sec += tomono.tv_sec;
850 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
852 EXPORT_SYMBOL_GPL(ktime_get_ts64);
855 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
857 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
858 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
859 * works on both 32 and 64 bit systems. On 32 bit systems the readout
860 * covers ~136 years of uptime which should be enough to prevent
861 * premature wrap arounds.
863 time64_t ktime_get_seconds(void)
865 struct timekeeper *tk = &tk_core.timekeeper;
867 WARN_ON(timekeeping_suspended);
868 return tk->ktime_sec;
870 EXPORT_SYMBOL_GPL(ktime_get_seconds);
873 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
875 * Returns the wall clock seconds since 1970. This replaces the
876 * get_seconds() interface which is not y2038 safe on 32bit systems.
878 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
879 * 32bit systems the access must be protected with the sequence
880 * counter to provide "atomic" access to the 64bit tk->xtime_sec
883 time64_t ktime_get_real_seconds(void)
885 struct timekeeper *tk = &tk_core.timekeeper;
889 if (IS_ENABLED(CONFIG_64BIT))
890 return tk->xtime_sec;
893 seq = read_seqcount_begin(&tk_core.seq);
894 seconds = tk->xtime_sec;
896 } while (read_seqcount_retry(&tk_core.seq, seq));
900 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
903 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
904 * but without the sequence counter protect. This internal function
905 * is called just when timekeeping lock is already held.
907 time64_t __ktime_get_real_seconds(void)
909 struct timekeeper *tk = &tk_core.timekeeper;
911 return tk->xtime_sec;
915 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
916 * @systime_snapshot: pointer to struct receiving the system time snapshot
918 void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
920 struct timekeeper *tk = &tk_core.timekeeper;
928 WARN_ON_ONCE(timekeeping_suspended);
931 seq = read_seqcount_begin(&tk_core.seq);
933 now = tk->tkr_mono.read(tk->tkr_mono.clock);
934 systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
935 systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
936 base_real = ktime_add(tk->tkr_mono.base,
937 tk_core.timekeeper.offs_real);
938 base_raw = tk->tkr_raw.base;
939 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
940 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
941 } while (read_seqcount_retry(&tk_core.seq, seq));
943 systime_snapshot->cycles = now;
944 systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
945 systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
947 EXPORT_SYMBOL_GPL(ktime_get_snapshot);
949 /* Scale base by mult/div checking for overflow */
950 static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
954 tmp = div64_u64_rem(*base, div, &rem);
956 if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
957 ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
968 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
969 * @history: Snapshot representing start of history
970 * @partial_history_cycles: Cycle offset into history (fractional part)
971 * @total_history_cycles: Total history length in cycles
972 * @discontinuity: True indicates clock was set on history period
973 * @ts: Cross timestamp that should be adjusted using
974 * partial/total ratio
976 * Helper function used by get_device_system_crosststamp() to correct the
977 * crosstimestamp corresponding to the start of the current interval to the
978 * system counter value (timestamp point) provided by the driver. The
979 * total_history_* quantities are the total history starting at the provided
980 * reference point and ending at the start of the current interval. The cycle
981 * count between the driver timestamp point and the start of the current
982 * interval is partial_history_cycles.
984 static int adjust_historical_crosststamp(struct system_time_snapshot *history,
985 cycle_t partial_history_cycles,
986 cycle_t total_history_cycles,
988 struct system_device_crosststamp *ts)
990 struct timekeeper *tk = &tk_core.timekeeper;
991 u64 corr_raw, corr_real;
995 if (total_history_cycles == 0 || partial_history_cycles == 0)
998 /* Interpolate shortest distance from beginning or end of history */
999 interp_forward = partial_history_cycles > total_history_cycles/2 ?
1001 partial_history_cycles = interp_forward ?
1002 total_history_cycles - partial_history_cycles :
1003 partial_history_cycles;
1006 * Scale the monotonic raw time delta by:
1007 * partial_history_cycles / total_history_cycles
1009 corr_raw = (u64)ktime_to_ns(
1010 ktime_sub(ts->sys_monoraw, history->raw));
1011 ret = scale64_check_overflow(partial_history_cycles,
1012 total_history_cycles, &corr_raw);
1017 * If there is a discontinuity in the history, scale monotonic raw
1019 * mult(real)/mult(raw) yielding the realtime correction
1020 * Otherwise, calculate the realtime correction similar to monotonic
1023 if (discontinuity) {
1024 corr_real = mul_u64_u32_div
1025 (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1027 corr_real = (u64)ktime_to_ns(
1028 ktime_sub(ts->sys_realtime, history->real));
1029 ret = scale64_check_overflow(partial_history_cycles,
1030 total_history_cycles, &corr_real);
1035 /* Fixup monotonic raw and real time time values */
1036 if (interp_forward) {
1037 ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1038 ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1040 ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1041 ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1048 * cycle_between - true if test occurs chronologically between before and after
1050 static bool cycle_between(cycle_t before, cycle_t test, cycle_t after)
1052 if (test > before && test < after)
1054 if (test < before && before > after)
1060 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1061 * @get_time_fn: Callback to get simultaneous device time and
1062 * system counter from the device driver
1063 * @ctx: Context passed to get_time_fn()
1064 * @history_begin: Historical reference point used to interpolate system
1065 * time when counter provided by the driver is before the current interval
1066 * @xtstamp: Receives simultaneously captured system and device time
1068 * Reads a timestamp from a device and correlates it to system time
1070 int get_device_system_crosststamp(int (*get_time_fn)
1071 (ktime_t *device_time,
1072 struct system_counterval_t *sys_counterval,
1075 struct system_time_snapshot *history_begin,
1076 struct system_device_crosststamp *xtstamp)
1078 struct system_counterval_t system_counterval;
1079 struct timekeeper *tk = &tk_core.timekeeper;
1080 cycle_t cycles, now, interval_start;
1081 unsigned int clock_was_set_seq = 0;
1082 ktime_t base_real, base_raw;
1083 u64 nsec_real, nsec_raw;
1084 u8 cs_was_changed_seq;
1090 seq = read_seqcount_begin(&tk_core.seq);
1092 * Try to synchronously capture device time and a system
1093 * counter value calling back into the device driver
1095 ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1100 * Verify that the clocksource associated with the captured
1101 * system counter value is the same as the currently installed
1102 * timekeeper clocksource
1104 if (tk->tkr_mono.clock != system_counterval.cs)
1106 cycles = system_counterval.cycles;
1109 * Check whether the system counter value provided by the
1110 * device driver is on the current timekeeping interval.
1112 now = tk->tkr_mono.read(tk->tkr_mono.clock);
1113 interval_start = tk->tkr_mono.cycle_last;
1114 if (!cycle_between(interval_start, cycles, now)) {
1115 clock_was_set_seq = tk->clock_was_set_seq;
1116 cs_was_changed_seq = tk->cs_was_changed_seq;
1117 cycles = interval_start;
1123 base_real = ktime_add(tk->tkr_mono.base,
1124 tk_core.timekeeper.offs_real);
1125 base_raw = tk->tkr_raw.base;
1127 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1128 system_counterval.cycles);
1129 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1130 system_counterval.cycles);
1131 } while (read_seqcount_retry(&tk_core.seq, seq));
1133 xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1134 xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1137 * Interpolate if necessary, adjusting back from the start of the
1141 cycle_t partial_history_cycles, total_history_cycles;
1145 * Check that the counter value occurs after the provided
1146 * history reference and that the history doesn't cross a
1147 * clocksource change
1149 if (!history_begin ||
1150 !cycle_between(history_begin->cycles,
1151 system_counterval.cycles, cycles) ||
1152 history_begin->cs_was_changed_seq != cs_was_changed_seq)
1154 partial_history_cycles = cycles - system_counterval.cycles;
1155 total_history_cycles = cycles - history_begin->cycles;
1157 history_begin->clock_was_set_seq != clock_was_set_seq;
1159 ret = adjust_historical_crosststamp(history_begin,
1160 partial_history_cycles,
1161 total_history_cycles,
1162 discontinuity, xtstamp);
1169 EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1172 * do_gettimeofday - Returns the time of day in a timeval
1173 * @tv: pointer to the timeval to be set
1175 * NOTE: Users should be converted to using getnstimeofday()
1177 void do_gettimeofday(struct timeval *tv)
1179 struct timespec64 now;
1181 getnstimeofday64(&now);
1182 tv->tv_sec = now.tv_sec;
1183 tv->tv_usec = now.tv_nsec/1000;
1185 EXPORT_SYMBOL(do_gettimeofday);
1188 * do_settimeofday64 - Sets the time of day.
1189 * @ts: pointer to the timespec64 variable containing the new time
1191 * Sets the time of day to the new time and update NTP and notify hrtimers
1193 int do_settimeofday64(const struct timespec64 *ts)
1195 struct timekeeper *tk = &tk_core.timekeeper;
1196 struct timespec64 ts_delta, xt;
1197 unsigned long flags;
1200 if (!timespec64_valid_strict(ts))
1203 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1204 write_seqcount_begin(&tk_core.seq);
1206 timekeeping_forward_now(tk);
1209 ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
1210 ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
1212 if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1217 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1219 tk_set_xtime(tk, ts);
1221 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1223 write_seqcount_end(&tk_core.seq);
1224 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1226 /* signal hrtimers about time change */
1231 EXPORT_SYMBOL(do_settimeofday64);
1234 * timekeeping_inject_offset - Adds or subtracts from the current time.
1235 * @tv: pointer to the timespec variable containing the offset
1237 * Adds or subtracts an offset value from the current time.
1239 int timekeeping_inject_offset(struct timespec *ts)
1241 struct timekeeper *tk = &tk_core.timekeeper;
1242 unsigned long flags;
1243 struct timespec64 ts64, tmp;
1246 if (!timespec_inject_offset_valid(ts))
1249 ts64 = timespec_to_timespec64(*ts);
1251 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1252 write_seqcount_begin(&tk_core.seq);
1254 timekeeping_forward_now(tk);
1256 /* Make sure the proposed value is valid */
1257 tmp = timespec64_add(tk_xtime(tk), ts64);
1258 if (timespec64_compare(&tk->wall_to_monotonic, &ts64) > 0 ||
1259 !timespec64_valid_strict(&tmp)) {
1264 tk_xtime_add(tk, &ts64);
1265 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
1267 error: /* even if we error out, we forwarded the time, so call update */
1268 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1270 write_seqcount_end(&tk_core.seq);
1271 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1273 /* signal hrtimers about time change */
1278 EXPORT_SYMBOL(timekeeping_inject_offset);
1282 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
1285 s32 timekeeping_get_tai_offset(void)
1287 struct timekeeper *tk = &tk_core.timekeeper;
1292 seq = read_seqcount_begin(&tk_core.seq);
1293 ret = tk->tai_offset;
1294 } while (read_seqcount_retry(&tk_core.seq, seq));
1300 * __timekeeping_set_tai_offset - Lock free worker function
1303 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1305 tk->tai_offset = tai_offset;
1306 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1310 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
1313 void timekeeping_set_tai_offset(s32 tai_offset)
1315 struct timekeeper *tk = &tk_core.timekeeper;
1316 unsigned long flags;
1318 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1319 write_seqcount_begin(&tk_core.seq);
1320 __timekeeping_set_tai_offset(tk, tai_offset);
1321 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1322 write_seqcount_end(&tk_core.seq);
1323 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1328 * change_clocksource - Swaps clocksources if a new one is available
1330 * Accumulates current time interval and initializes new clocksource
1332 static int change_clocksource(void *data)
1334 struct timekeeper *tk = &tk_core.timekeeper;
1335 struct clocksource *new, *old;
1336 unsigned long flags;
1338 new = (struct clocksource *) data;
1340 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1341 write_seqcount_begin(&tk_core.seq);
1343 timekeeping_forward_now(tk);
1345 * If the cs is in module, get a module reference. Succeeds
1346 * for built-in code (owner == NULL) as well.
1348 if (try_module_get(new->owner)) {
1349 if (!new->enable || new->enable(new) == 0) {
1350 old = tk->tkr_mono.clock;
1351 tk_setup_internals(tk, new);
1354 module_put(old->owner);
1356 module_put(new->owner);
1359 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1361 write_seqcount_end(&tk_core.seq);
1362 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1368 * timekeeping_notify - Install a new clock source
1369 * @clock: pointer to the clock source
1371 * This function is called from clocksource.c after a new, better clock
1372 * source has been registered. The caller holds the clocksource_mutex.
1374 int timekeeping_notify(struct clocksource *clock)
1376 struct timekeeper *tk = &tk_core.timekeeper;
1378 if (tk->tkr_mono.clock == clock)
1380 stop_machine(change_clocksource, clock, NULL);
1381 tick_clock_notify();
1382 return tk->tkr_mono.clock == clock ? 0 : -1;
1386 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1387 * @ts: pointer to the timespec64 to be set
1389 * Returns the raw monotonic time (completely un-modified by ntp)
1391 void getrawmonotonic64(struct timespec64 *ts)
1393 struct timekeeper *tk = &tk_core.timekeeper;
1394 struct timespec64 ts64;
1399 seq = read_seqcount_begin(&tk_core.seq);
1400 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1401 ts64 = tk->raw_time;
1403 } while (read_seqcount_retry(&tk_core.seq, seq));
1405 timespec64_add_ns(&ts64, nsecs);
1408 EXPORT_SYMBOL(getrawmonotonic64);
1412 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1414 int timekeeping_valid_for_hres(void)
1416 struct timekeeper *tk = &tk_core.timekeeper;
1421 seq = read_seqcount_begin(&tk_core.seq);
1423 ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1425 } while (read_seqcount_retry(&tk_core.seq, seq));
1431 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1433 u64 timekeeping_max_deferment(void)
1435 struct timekeeper *tk = &tk_core.timekeeper;
1440 seq = read_seqcount_begin(&tk_core.seq);
1442 ret = tk->tkr_mono.clock->max_idle_ns;
1444 } while (read_seqcount_retry(&tk_core.seq, seq));
1450 * read_persistent_clock - Return time from the persistent clock.
1452 * Weak dummy function for arches that do not yet support it.
1453 * Reads the time from the battery backed persistent clock.
1454 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1456 * XXX - Do be sure to remove it once all arches implement it.
1458 void __weak read_persistent_clock(struct timespec *ts)
1464 void __weak read_persistent_clock64(struct timespec64 *ts64)
1468 read_persistent_clock(&ts);
1469 *ts64 = timespec_to_timespec64(ts);
1473 * read_boot_clock64 - Return time of the system start.
1475 * Weak dummy function for arches that do not yet support it.
1476 * Function to read the exact time the system has been started.
1477 * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported.
1479 * XXX - Do be sure to remove it once all arches implement it.
1481 void __weak read_boot_clock64(struct timespec64 *ts)
1487 /* Flag for if timekeeping_resume() has injected sleeptime */
1488 static bool sleeptime_injected;
1490 /* Flag for if there is a persistent clock on this platform */
1491 static bool persistent_clock_exists;
1494 * timekeeping_init - Initializes the clocksource and common timekeeping values
1496 void __init timekeeping_init(void)
1498 struct timekeeper *tk = &tk_core.timekeeper;
1499 struct clocksource *clock;
1500 unsigned long flags;
1501 struct timespec64 now, boot, tmp;
1503 read_persistent_clock64(&now);
1504 if (!timespec64_valid_strict(&now)) {
1505 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1506 " Check your CMOS/BIOS settings.\n");
1509 } else if (now.tv_sec || now.tv_nsec)
1510 persistent_clock_exists = true;
1512 read_boot_clock64(&boot);
1513 if (!timespec64_valid_strict(&boot)) {
1514 pr_warn("WARNING: Boot clock returned invalid value!\n"
1515 " Check your CMOS/BIOS settings.\n");
1520 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1521 write_seqcount_begin(&tk_core.seq);
1524 clock = clocksource_default_clock();
1526 clock->enable(clock);
1527 tk_setup_internals(tk, clock);
1529 tk_set_xtime(tk, &now);
1530 tk->raw_time.tv_sec = 0;
1531 tk->raw_time.tv_nsec = 0;
1532 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1533 boot = tk_xtime(tk);
1535 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1536 tk_set_wall_to_mono(tk, tmp);
1538 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1540 write_seqcount_end(&tk_core.seq);
1541 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1544 /* time in seconds when suspend began for persistent clock */
1545 static struct timespec64 timekeeping_suspend_time;
1548 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1549 * @delta: pointer to a timespec delta value
1551 * Takes a timespec offset measuring a suspend interval and properly
1552 * adds the sleep offset to the timekeeping variables.
1554 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1555 struct timespec64 *delta)
1557 if (!timespec64_valid_strict(delta)) {
1558 printk_deferred(KERN_WARNING
1559 "__timekeeping_inject_sleeptime: Invalid "
1560 "sleep delta value!\n");
1563 tk_xtime_add(tk, delta);
1564 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1565 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1566 tk_debug_account_sleep_time(delta);
1569 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1571 * We have three kinds of time sources to use for sleep time
1572 * injection, the preference order is:
1573 * 1) non-stop clocksource
1574 * 2) persistent clock (ie: RTC accessible when irqs are off)
1577 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1578 * If system has neither 1) nor 2), 3) will be used finally.
1581 * If timekeeping has injected sleeptime via either 1) or 2),
1582 * 3) becomes needless, so in this case we don't need to call
1583 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1586 bool timekeeping_rtc_skipresume(void)
1588 return sleeptime_injected;
1592 * 1) can be determined whether to use or not only when doing
1593 * timekeeping_resume() which is invoked after rtc_suspend(),
1594 * so we can't skip rtc_suspend() surely if system has 1).
1596 * But if system has 2), 2) will definitely be used, so in this
1597 * case we don't need to call rtc_suspend(), and this is what
1598 * timekeeping_rtc_skipsuspend() means.
1600 bool timekeeping_rtc_skipsuspend(void)
1602 return persistent_clock_exists;
1606 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1607 * @delta: pointer to a timespec64 delta value
1609 * This hook is for architectures that cannot support read_persistent_clock64
1610 * because their RTC/persistent clock is only accessible when irqs are enabled.
1611 * and also don't have an effective nonstop clocksource.
1613 * This function should only be called by rtc_resume(), and allows
1614 * a suspend offset to be injected into the timekeeping values.
1616 void timekeeping_inject_sleeptime64(struct timespec64 *delta)
1618 struct timekeeper *tk = &tk_core.timekeeper;
1619 unsigned long flags;
1621 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1622 write_seqcount_begin(&tk_core.seq);
1624 timekeeping_forward_now(tk);
1626 __timekeeping_inject_sleeptime(tk, delta);
1628 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1630 write_seqcount_end(&tk_core.seq);
1631 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1633 /* signal hrtimers about time change */
1639 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1641 void timekeeping_resume(void)
1643 struct timekeeper *tk = &tk_core.timekeeper;
1644 struct clocksource *clock = tk->tkr_mono.clock;
1645 unsigned long flags;
1646 struct timespec64 ts_new, ts_delta;
1649 sleeptime_injected = false;
1650 read_persistent_clock64(&ts_new);
1652 clockevents_resume();
1653 clocksource_resume();
1655 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1656 write_seqcount_begin(&tk_core.seq);
1659 * After system resumes, we need to calculate the suspended time and
1660 * compensate it for the OS time. There are 3 sources that could be
1661 * used: Nonstop clocksource during suspend, persistent clock and rtc
1664 * One specific platform may have 1 or 2 or all of them, and the
1665 * preference will be:
1666 * suspend-nonstop clocksource -> persistent clock -> rtc
1667 * The less preferred source will only be tried if there is no better
1668 * usable source. The rtc part is handled separately in rtc core code.
1670 cycle_now = tk->tkr_mono.read(clock);
1671 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1672 cycle_now > tk->tkr_mono.cycle_last) {
1673 u64 nsec, cyc_delta;
1675 cyc_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
1677 nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift);
1678 ts_delta = ns_to_timespec64(nsec);
1679 sleeptime_injected = true;
1680 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1681 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1682 sleeptime_injected = true;
1685 if (sleeptime_injected)
1686 __timekeeping_inject_sleeptime(tk, &ts_delta);
1688 /* Re-base the last cycle value */
1689 tk->tkr_mono.cycle_last = cycle_now;
1690 tk->tkr_raw.cycle_last = cycle_now;
1693 timekeeping_suspended = 0;
1694 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1695 write_seqcount_end(&tk_core.seq);
1696 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1698 touch_softlockup_watchdog();
1704 int timekeeping_suspend(void)
1706 struct timekeeper *tk = &tk_core.timekeeper;
1707 unsigned long flags;
1708 struct timespec64 delta, delta_delta;
1709 static struct timespec64 old_delta;
1711 read_persistent_clock64(&timekeeping_suspend_time);
1714 * On some systems the persistent_clock can not be detected at
1715 * timekeeping_init by its return value, so if we see a valid
1716 * value returned, update the persistent_clock_exists flag.
1718 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1719 persistent_clock_exists = true;
1721 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1722 write_seqcount_begin(&tk_core.seq);
1723 timekeeping_forward_now(tk);
1724 timekeeping_suspended = 1;
1726 if (persistent_clock_exists) {
1728 * To avoid drift caused by repeated suspend/resumes,
1729 * which each can add ~1 second drift error,
1730 * try to compensate so the difference in system time
1731 * and persistent_clock time stays close to constant.
1733 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1734 delta_delta = timespec64_sub(delta, old_delta);
1735 if (abs(delta_delta.tv_sec) >= 2) {
1737 * if delta_delta is too large, assume time correction
1738 * has occurred and set old_delta to the current delta.
1742 /* Otherwise try to adjust old_system to compensate */
1743 timekeeping_suspend_time =
1744 timespec64_add(timekeeping_suspend_time, delta_delta);
1748 timekeeping_update(tk, TK_MIRROR);
1749 halt_fast_timekeeper(tk);
1750 write_seqcount_end(&tk_core.seq);
1751 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1754 clocksource_suspend();
1755 clockevents_suspend();
1760 /* sysfs resume/suspend bits for timekeeping */
1761 static struct syscore_ops timekeeping_syscore_ops = {
1762 .resume = timekeeping_resume,
1763 .suspend = timekeeping_suspend,
1766 static int __init timekeeping_init_ops(void)
1768 register_syscore_ops(&timekeeping_syscore_ops);
1771 device_initcall(timekeeping_init_ops);
1774 * Apply a multiplier adjustment to the timekeeper
1776 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1781 s64 interval = tk->cycle_interval;
1785 mult_adj = -mult_adj;
1786 interval = -interval;
1789 mult_adj <<= adj_scale;
1790 interval <<= adj_scale;
1791 offset <<= adj_scale;
1794 * So the following can be confusing.
1796 * To keep things simple, lets assume mult_adj == 1 for now.
1798 * When mult_adj != 1, remember that the interval and offset values
1799 * have been appropriately scaled so the math is the same.
1801 * The basic idea here is that we're increasing the multiplier
1802 * by one, this causes the xtime_interval to be incremented by
1803 * one cycle_interval. This is because:
1804 * xtime_interval = cycle_interval * mult
1805 * So if mult is being incremented by one:
1806 * xtime_interval = cycle_interval * (mult + 1)
1808 * xtime_interval = (cycle_interval * mult) + cycle_interval
1809 * Which can be shortened to:
1810 * xtime_interval += cycle_interval
1812 * So offset stores the non-accumulated cycles. Thus the current
1813 * time (in shifted nanoseconds) is:
1814 * now = (offset * adj) + xtime_nsec
1815 * Now, even though we're adjusting the clock frequency, we have
1816 * to keep time consistent. In other words, we can't jump back
1817 * in time, and we also want to avoid jumping forward in time.
1819 * So given the same offset value, we need the time to be the same
1820 * both before and after the freq adjustment.
1821 * now = (offset * adj_1) + xtime_nsec_1
1822 * now = (offset * adj_2) + xtime_nsec_2
1824 * (offset * adj_1) + xtime_nsec_1 =
1825 * (offset * adj_2) + xtime_nsec_2
1829 * (offset * adj_1) + xtime_nsec_1 =
1830 * (offset * (adj_1+1)) + xtime_nsec_2
1831 * (offset * adj_1) + xtime_nsec_1 =
1832 * (offset * adj_1) + offset + xtime_nsec_2
1833 * Canceling the sides:
1834 * xtime_nsec_1 = offset + xtime_nsec_2
1836 * xtime_nsec_2 = xtime_nsec_1 - offset
1837 * Which simplfies to:
1838 * xtime_nsec -= offset
1840 * XXX - TODO: Doc ntp_error calculation.
1842 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1843 /* NTP adjustment caused clocksource mult overflow */
1848 tk->tkr_mono.mult += mult_adj;
1849 tk->xtime_interval += interval;
1850 tk->tkr_mono.xtime_nsec -= offset;
1851 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1855 * Calculate the multiplier adjustment needed to match the frequency
1858 static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
1861 s64 interval = tk->cycle_interval;
1862 s64 xinterval = tk->xtime_interval;
1863 u32 base = tk->tkr_mono.clock->mult;
1864 u32 max = tk->tkr_mono.clock->maxadj;
1865 u32 cur_adj = tk->tkr_mono.mult;
1870 /* Remove any current error adj from freq calculation */
1871 if (tk->ntp_err_mult)
1872 xinterval -= tk->cycle_interval;
1874 tk->ntp_tick = ntp_tick_length();
1876 /* Calculate current error per tick */
1877 tick_error = ntp_tick_length() >> tk->ntp_error_shift;
1878 tick_error -= (xinterval + tk->xtime_remainder);
1880 /* Don't worry about correcting it if its small */
1881 if (likely((tick_error >= 0) && (tick_error <= interval)))
1884 /* preserve the direction of correction */
1885 negative = (tick_error < 0);
1887 /* If any adjustment would pass the max, just return */
1888 if (negative && (cur_adj - 1) <= (base - max))
1890 if (!negative && (cur_adj + 1) >= (base + max))
1893 * Sort out the magnitude of the correction, but
1894 * avoid making so large a correction that we go
1895 * over the max adjustment.
1898 tick_error = abs(tick_error);
1899 while (tick_error > interval) {
1900 u32 adj = 1 << (adj_scale + 1);
1902 /* Check if adjustment gets us within 1 unit from the max */
1903 if (negative && (cur_adj - adj) <= (base - max))
1905 if (!negative && (cur_adj + adj) >= (base + max))
1912 /* scale the corrections */
1913 timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
1917 * Adjust the timekeeper's multiplier to the correct frequency
1918 * and also to reduce the accumulated error value.
1920 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1922 /* Correct for the current frequency error */
1923 timekeeping_freqadjust(tk, offset);
1925 /* Next make a small adjustment to fix any cumulative error */
1926 if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
1927 tk->ntp_err_mult = 1;
1928 timekeeping_apply_adjustment(tk, offset, 0, 0);
1929 } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
1930 /* Undo any existing error adjustment */
1931 timekeeping_apply_adjustment(tk, offset, 1, 0);
1932 tk->ntp_err_mult = 0;
1935 if (unlikely(tk->tkr_mono.clock->maxadj &&
1936 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1937 > tk->tkr_mono.clock->maxadj))) {
1938 printk_once(KERN_WARNING
1939 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1940 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1941 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1945 * It may be possible that when we entered this function, xtime_nsec
1946 * was very small. Further, if we're slightly speeding the clocksource
1947 * in the code above, its possible the required corrective factor to
1948 * xtime_nsec could cause it to underflow.
1950 * Now, since we already accumulated the second, cannot simply roll
1951 * the accumulated second back, since the NTP subsystem has been
1952 * notified via second_overflow. So instead we push xtime_nsec forward
1953 * by the amount we underflowed, and add that amount into the error.
1955 * We'll correct this error next time through this function, when
1956 * xtime_nsec is not as small.
1958 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1959 s64 neg = -(s64)tk->tkr_mono.xtime_nsec;
1960 tk->tkr_mono.xtime_nsec = 0;
1961 tk->ntp_error += neg << tk->ntp_error_shift;
1966 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1968 * Helper function that accumulates the nsecs greater than a second
1969 * from the xtime_nsec field to the xtime_secs field.
1970 * It also calls into the NTP code to handle leapsecond processing.
1973 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1975 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1976 unsigned int clock_set = 0;
1978 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1981 tk->tkr_mono.xtime_nsec -= nsecps;
1984 /* Figure out if its a leap sec and apply if needed */
1985 leap = second_overflow(tk->xtime_sec);
1986 if (unlikely(leap)) {
1987 struct timespec64 ts;
1989 tk->xtime_sec += leap;
1993 tk_set_wall_to_mono(tk,
1994 timespec64_sub(tk->wall_to_monotonic, ts));
1996 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1998 clock_set = TK_CLOCK_WAS_SET;
2005 * logarithmic_accumulation - shifted accumulation of cycles
2007 * This functions accumulates a shifted interval of cycles into
2008 * into a shifted interval nanoseconds. Allows for O(log) accumulation
2011 * Returns the unconsumed cycles.
2013 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
2015 unsigned int *clock_set)
2017 cycle_t interval = tk->cycle_interval << shift;
2020 /* If the offset is smaller than a shifted interval, do nothing */
2021 if (offset < interval)
2024 /* Accumulate one shifted interval */
2026 tk->tkr_mono.cycle_last += interval;
2027 tk->tkr_raw.cycle_last += interval;
2029 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2030 *clock_set |= accumulate_nsecs_to_secs(tk);
2032 /* Accumulate raw time */
2033 raw_nsecs = (u64)tk->raw_interval << shift;
2034 raw_nsecs += tk->raw_time.tv_nsec;
2035 if (raw_nsecs >= NSEC_PER_SEC) {
2036 u64 raw_secs = raw_nsecs;
2037 raw_nsecs = do_div(raw_secs, NSEC_PER_SEC);
2038 tk->raw_time.tv_sec += raw_secs;
2040 tk->raw_time.tv_nsec = raw_nsecs;
2042 /* Accumulate error between NTP and clock interval */
2043 tk->ntp_error += tk->ntp_tick << shift;
2044 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2045 (tk->ntp_error_shift + shift);
2051 * update_wall_time - Uses the current clocksource to increment the wall time
2054 void update_wall_time(void)
2056 struct timekeeper *real_tk = &tk_core.timekeeper;
2057 struct timekeeper *tk = &shadow_timekeeper;
2059 int shift = 0, maxshift;
2060 unsigned int clock_set = 0;
2061 unsigned long flags;
2063 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2065 /* Make sure we're fully resumed: */
2066 if (unlikely(timekeeping_suspended))
2069 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2070 offset = real_tk->cycle_interval;
2072 offset = clocksource_delta(tk->tkr_mono.read(tk->tkr_mono.clock),
2073 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2076 /* Check if there's really nothing to do */
2077 if (offset < real_tk->cycle_interval)
2080 /* Do some additional sanity checking */
2081 timekeeping_check_update(real_tk, offset);
2084 * With NO_HZ we may have to accumulate many cycle_intervals
2085 * (think "ticks") worth of time at once. To do this efficiently,
2086 * we calculate the largest doubling multiple of cycle_intervals
2087 * that is smaller than the offset. We then accumulate that
2088 * chunk in one go, and then try to consume the next smaller
2091 shift = ilog2(offset) - ilog2(tk->cycle_interval);
2092 shift = max(0, shift);
2093 /* Bound shift to one less than what overflows tick_length */
2094 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2095 shift = min(shift, maxshift);
2096 while (offset >= tk->cycle_interval) {
2097 offset = logarithmic_accumulation(tk, offset, shift,
2099 if (offset < tk->cycle_interval<<shift)
2103 /* correct the clock when NTP error is too big */
2104 timekeeping_adjust(tk, offset);
2107 * XXX This can be killed once everyone converts
2108 * to the new update_vsyscall.
2110 old_vsyscall_fixup(tk);
2113 * Finally, make sure that after the rounding
2114 * xtime_nsec isn't larger than NSEC_PER_SEC
2116 clock_set |= accumulate_nsecs_to_secs(tk);
2118 write_seqcount_begin(&tk_core.seq);
2120 * Update the real timekeeper.
2122 * We could avoid this memcpy by switching pointers, but that
2123 * requires changes to all other timekeeper usage sites as
2124 * well, i.e. move the timekeeper pointer getter into the
2125 * spinlocked/seqcount protected sections. And we trade this
2126 * memcpy under the tk_core.seq against one before we start
2129 timekeeping_update(tk, clock_set);
2130 memcpy(real_tk, tk, sizeof(*tk));
2131 /* The memcpy must come last. Do not put anything here! */
2132 write_seqcount_end(&tk_core.seq);
2134 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2136 /* Have to call _delayed version, since in irq context*/
2137 clock_was_set_delayed();
2141 * getboottime64 - Return the real time of system boot.
2142 * @ts: pointer to the timespec64 to be set
2144 * Returns the wall-time of boot in a timespec64.
2146 * This is based on the wall_to_monotonic offset and the total suspend
2147 * time. Calls to settimeofday will affect the value returned (which
2148 * basically means that however wrong your real time clock is at boot time,
2149 * you get the right time here).
2151 void getboottime64(struct timespec64 *ts)
2153 struct timekeeper *tk = &tk_core.timekeeper;
2154 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2156 *ts = ktime_to_timespec64(t);
2158 EXPORT_SYMBOL_GPL(getboottime64);
2160 unsigned long get_seconds(void)
2162 struct timekeeper *tk = &tk_core.timekeeper;
2164 return tk->xtime_sec;
2166 EXPORT_SYMBOL(get_seconds);
2168 struct timespec __current_kernel_time(void)
2170 struct timekeeper *tk = &tk_core.timekeeper;
2172 return timespec64_to_timespec(tk_xtime(tk));
2175 struct timespec64 current_kernel_time64(void)
2177 struct timekeeper *tk = &tk_core.timekeeper;
2178 struct timespec64 now;
2182 seq = read_seqcount_begin(&tk_core.seq);
2185 } while (read_seqcount_retry(&tk_core.seq, seq));
2189 EXPORT_SYMBOL(current_kernel_time64);
2191 struct timespec64 get_monotonic_coarse64(void)
2193 struct timekeeper *tk = &tk_core.timekeeper;
2194 struct timespec64 now, mono;
2198 seq = read_seqcount_begin(&tk_core.seq);
2201 mono = tk->wall_to_monotonic;
2202 } while (read_seqcount_retry(&tk_core.seq, seq));
2204 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
2205 now.tv_nsec + mono.tv_nsec);
2209 EXPORT_SYMBOL(get_monotonic_coarse64);
2212 * Must hold jiffies_lock
2214 void do_timer(unsigned long ticks)
2216 jiffies_64 += ticks;
2217 calc_global_load(ticks);
2221 * ktime_get_update_offsets_now - hrtimer helper
2222 * @cwsseq: pointer to check and store the clock was set sequence number
2223 * @offs_real: pointer to storage for monotonic -> realtime offset
2224 * @offs_boot: pointer to storage for monotonic -> boottime offset
2225 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2227 * Returns current monotonic time and updates the offsets if the
2228 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2231 * Called from hrtimer_interrupt() or retrigger_next_event()
2233 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2234 ktime_t *offs_boot, ktime_t *offs_tai)
2236 struct timekeeper *tk = &tk_core.timekeeper;
2242 seq = read_seqcount_begin(&tk_core.seq);
2244 base = tk->tkr_mono.base;
2245 nsecs = timekeeping_get_ns(&tk->tkr_mono);
2246 base = ktime_add_ns(base, nsecs);
2248 if (*cwsseq != tk->clock_was_set_seq) {
2249 *cwsseq = tk->clock_was_set_seq;
2250 *offs_real = tk->offs_real;
2251 *offs_boot = tk->offs_boot;
2252 *offs_tai = tk->offs_tai;
2255 /* Handle leapsecond insertion adjustments */
2256 if (unlikely(base.tv64 >= tk->next_leap_ktime.tv64))
2257 *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2259 } while (read_seqcount_retry(&tk_core.seq, seq));
2265 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2267 int do_adjtimex(struct timex *txc)
2269 struct timekeeper *tk = &tk_core.timekeeper;
2270 unsigned long flags;
2271 struct timespec64 ts;
2275 /* Validate the data before disabling interrupts */
2276 ret = ntp_validate_timex(txc);
2280 if (txc->modes & ADJ_SETOFFSET) {
2281 struct timespec delta;
2282 delta.tv_sec = txc->time.tv_sec;
2283 delta.tv_nsec = txc->time.tv_usec;
2284 if (!(txc->modes & ADJ_NANO))
2285 delta.tv_nsec *= 1000;
2286 ret = timekeeping_inject_offset(&delta);
2291 getnstimeofday64(&ts);
2293 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2294 write_seqcount_begin(&tk_core.seq);
2296 orig_tai = tai = tk->tai_offset;
2297 ret = __do_adjtimex(txc, &ts, &tai);
2299 if (tai != orig_tai) {
2300 __timekeeping_set_tai_offset(tk, tai);
2301 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2303 tk_update_leap_state(tk);
2305 write_seqcount_end(&tk_core.seq);
2306 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2308 if (tai != orig_tai)
2311 ntp_notify_cmos_timer();
2316 #ifdef CONFIG_NTP_PPS
2318 * hardpps() - Accessor function to NTP __hardpps function
2320 void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2322 unsigned long flags;
2324 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2325 write_seqcount_begin(&tk_core.seq);
2327 __hardpps(phase_ts, raw_ts);
2329 write_seqcount_end(&tk_core.seq);
2330 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2332 EXPORT_SYMBOL(hardpps);
2336 * xtime_update() - advances the timekeeping infrastructure
2337 * @ticks: number of ticks, that have elapsed since the last call.
2339 * Must be called with interrupts disabled.
2341 void xtime_update(unsigned long ticks)
2343 write_seqlock(&jiffies_lock);
2345 write_sequnlock(&jiffies_lock);