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/timex.h>
23 #include <linux/tick.h>
24 #include <linux/stop_machine.h>
25 #include <linux/pvclock_gtod.h>
26 #include <linux/compiler.h>
28 #include "tick-internal.h"
29 #include "ntp_internal.h"
30 #include "timekeeping_internal.h"
32 #define TK_CLEAR_NTP (1 << 0)
33 #define TK_MIRROR (1 << 1)
34 #define TK_CLOCK_WAS_SET (1 << 2)
37 * The most important data for readout fits into a single 64 byte
42 struct timekeeper timekeeper;
43 } tk_core ____cacheline_aligned = {
44 .seq = SEQCNT_ZERO(tk_core.seq),
47 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
48 static struct timekeeper shadow_timekeeper;
51 * struct tk_fast - NMI safe timekeeper
52 * @seq: Sequence counter for protecting updates. The lowest bit
53 * is the index for the tk_read_base array
54 * @base: tk_read_base array. Access is indexed by the lowest bit of
57 * See @update_fast_timekeeper() below.
61 struct tk_read_base base[2];
64 static struct tk_fast tk_fast_mono ____cacheline_aligned;
65 static struct tk_fast tk_fast_raw ____cacheline_aligned;
67 /* flag for if timekeeping is suspended */
68 int __read_mostly timekeeping_suspended;
70 static inline void tk_normalize_xtime(struct timekeeper *tk)
72 while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
73 tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
78 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
82 ts.tv_sec = tk->xtime_sec;
83 ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
87 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
89 tk->xtime_sec = ts->tv_sec;
90 tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
93 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
95 tk->xtime_sec += ts->tv_sec;
96 tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
97 tk_normalize_xtime(tk);
100 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
102 struct timespec64 tmp;
105 * Verify consistency of: offset_real = -wall_to_monotonic
106 * before modifying anything
108 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
109 -tk->wall_to_monotonic.tv_nsec);
110 WARN_ON_ONCE(tk->offs_real.tv64 != timespec64_to_ktime(tmp).tv64);
111 tk->wall_to_monotonic = wtm;
112 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
113 tk->offs_real = timespec64_to_ktime(tmp);
114 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
117 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
119 tk->offs_boot = ktime_add(tk->offs_boot, delta);
123 * tk_clock_read - atomic clocksource read() helper
125 * This helper is necessary to use in the read paths because, while the
126 * seqlock ensures we don't return a bad value while structures are updated,
127 * it doesn't protect from potential crashes. There is the possibility that
128 * the tkr's clocksource may change between the read reference, and the
129 * clock reference passed to the read function. This can cause crashes if
130 * the wrong clocksource is passed to the wrong read function.
131 * This isn't necessary to use when holding the timekeeper_lock or doing
132 * a read of the fast-timekeeper tkrs (which is protected by its own locking
135 static inline u64 tk_clock_read(struct tk_read_base *tkr)
137 struct clocksource *clock = READ_ONCE(tkr->clock);
139 return clock->read(clock);
142 #ifdef CONFIG_DEBUG_TIMEKEEPING
143 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
145 static void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
148 cycle_t max_cycles = tk->tkr_mono.clock->max_cycles;
149 const char *name = tk->tkr_mono.clock->name;
151 if (offset > max_cycles) {
152 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
153 offset, name, max_cycles);
154 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
156 if (offset > (max_cycles >> 1)) {
157 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
158 offset, name, max_cycles >> 1);
159 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
163 if (tk->underflow_seen) {
164 if (jiffies - tk->last_warning > WARNING_FREQ) {
165 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
166 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
167 printk_deferred(" Your kernel is probably still fine.\n");
168 tk->last_warning = jiffies;
170 tk->underflow_seen = 0;
173 if (tk->overflow_seen) {
174 if (jiffies - tk->last_warning > WARNING_FREQ) {
175 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
176 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
177 printk_deferred(" Your kernel is probably still fine.\n");
178 tk->last_warning = jiffies;
180 tk->overflow_seen = 0;
184 static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
186 struct timekeeper *tk = &tk_core.timekeeper;
187 cycle_t now, last, mask, max, delta;
191 * Since we're called holding a seqlock, the data may shift
192 * under us while we're doing the calculation. This can cause
193 * false positives, since we'd note a problem but throw the
194 * results away. So nest another seqlock here to atomically
195 * grab the points we are checking with.
198 seq = read_seqcount_begin(&tk_core.seq);
199 now = tk_clock_read(tkr);
200 last = tkr->cycle_last;
202 max = tkr->clock->max_cycles;
203 } while (read_seqcount_retry(&tk_core.seq, seq));
205 delta = clocksource_delta(now, last, mask);
208 * Try to catch underflows by checking if we are seeing small
209 * mask-relative negative values.
211 if (unlikely((~delta & mask) < (mask >> 3))) {
212 tk->underflow_seen = 1;
216 /* Cap delta value to the max_cycles values to avoid mult overflows */
217 if (unlikely(delta > max)) {
218 tk->overflow_seen = 1;
219 delta = tkr->clock->max_cycles;
225 static inline void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
228 static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
230 cycle_t cycle_now, delta;
232 /* read clocksource */
233 cycle_now = tk_clock_read(tkr);
235 /* calculate the delta since the last update_wall_time */
236 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
243 * tk_setup_internals - Set up internals to use clocksource clock.
245 * @tk: The target timekeeper to setup.
246 * @clock: Pointer to clocksource.
248 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
249 * pair and interval request.
251 * Unless you're the timekeeping code, you should not be using this!
253 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
256 u64 tmp, ntpinterval;
257 struct clocksource *old_clock;
259 ++tk->cs_was_changed_seq;
260 old_clock = tk->tkr_mono.clock;
261 tk->tkr_mono.clock = clock;
262 tk->tkr_mono.mask = clock->mask;
263 tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
265 tk->tkr_raw.clock = clock;
266 tk->tkr_raw.mask = clock->mask;
267 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
269 /* Do the ns -> cycle conversion first, using original mult */
270 tmp = NTP_INTERVAL_LENGTH;
271 tmp <<= clock->shift;
273 tmp += clock->mult/2;
274 do_div(tmp, clock->mult);
278 interval = (cycle_t) tmp;
279 tk->cycle_interval = interval;
281 /* Go back from cycles -> shifted ns */
282 tk->xtime_interval = (u64) interval * clock->mult;
283 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
284 tk->raw_interval = interval * clock->mult;
286 /* if changing clocks, convert xtime_nsec shift units */
288 int shift_change = clock->shift - old_clock->shift;
289 if (shift_change < 0)
290 tk->tkr_mono.xtime_nsec >>= -shift_change;
292 tk->tkr_mono.xtime_nsec <<= shift_change;
294 tk->tkr_raw.xtime_nsec = 0;
296 tk->tkr_mono.shift = clock->shift;
297 tk->tkr_raw.shift = clock->shift;
300 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
301 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
304 * The timekeeper keeps its own mult values for the currently
305 * active clocksource. These value will be adjusted via NTP
306 * to counteract clock drifting.
308 tk->tkr_mono.mult = clock->mult;
309 tk->tkr_raw.mult = clock->mult;
310 tk->ntp_err_mult = 0;
313 /* Timekeeper helper functions. */
315 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
316 static u32 default_arch_gettimeoffset(void) { return 0; }
317 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
319 static inline u32 arch_gettimeoffset(void) { return 0; }
322 static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr,
327 nsec = delta * tkr->mult + tkr->xtime_nsec;
330 /* If arch requires, add in get_arch_timeoffset() */
331 return nsec + arch_gettimeoffset();
334 static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
338 delta = timekeeping_get_delta(tkr);
339 return timekeeping_delta_to_ns(tkr, delta);
342 static inline s64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
347 /* calculate the delta since the last update_wall_time */
348 delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
349 return timekeeping_delta_to_ns(tkr, delta);
353 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
354 * @tkr: Timekeeping readout base from which we take the update
356 * We want to use this from any context including NMI and tracing /
357 * instrumenting the timekeeping code itself.
359 * Employ the latch technique; see @raw_write_seqcount_latch.
361 * So if a NMI hits the update of base[0] then it will use base[1]
362 * which is still consistent. In the worst case this can result is a
363 * slightly wrong timestamp (a few nanoseconds). See
364 * @ktime_get_mono_fast_ns.
366 static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
368 struct tk_read_base *base = tkf->base;
370 /* Force readers off to base[1] */
371 raw_write_seqcount_latch(&tkf->seq);
374 memcpy(base, tkr, sizeof(*base));
376 /* Force readers back to base[0] */
377 raw_write_seqcount_latch(&tkf->seq);
380 memcpy(base + 1, base, sizeof(*base));
384 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
386 * This timestamp is not guaranteed to be monotonic across an update.
387 * The timestamp is calculated by:
389 * now = base_mono + clock_delta * slope
391 * So if the update lowers the slope, readers who are forced to the
392 * not yet updated second array are still using the old steeper slope.
401 * |12345678---> reader order
407 * So reader 6 will observe time going backwards versus reader 5.
409 * While other CPUs are likely to be able observe that, the only way
410 * for a CPU local observation is when an NMI hits in the middle of
411 * the update. Timestamps taken from that NMI context might be ahead
412 * of the following timestamps. Callers need to be aware of that and
415 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
417 struct tk_read_base *tkr;
422 seq = raw_read_seqcount_latch(&tkf->seq);
423 tkr = tkf->base + (seq & 0x01);
424 now = ktime_to_ns(tkr->base);
426 now += timekeeping_delta_to_ns(tkr,
431 } while (read_seqcount_retry(&tkf->seq, seq));
436 u64 ktime_get_mono_fast_ns(void)
438 return __ktime_get_fast_ns(&tk_fast_mono);
440 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
442 u64 ktime_get_raw_fast_ns(void)
444 return __ktime_get_fast_ns(&tk_fast_raw);
446 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
448 /* Suspend-time cycles value for halted fast timekeeper. */
449 static cycle_t cycles_at_suspend;
451 static cycle_t dummy_clock_read(struct clocksource *cs)
453 return cycles_at_suspend;
456 static struct clocksource dummy_clock = {
457 .read = dummy_clock_read,
461 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
462 * @tk: Timekeeper to snapshot.
464 * It generally is unsafe to access the clocksource after timekeeping has been
465 * suspended, so take a snapshot of the readout base of @tk and use it as the
466 * fast timekeeper's readout base while suspended. It will return the same
467 * number of cycles every time until timekeeping is resumed at which time the
468 * proper readout base for the fast timekeeper will be restored automatically.
470 static void halt_fast_timekeeper(struct timekeeper *tk)
472 static struct tk_read_base tkr_dummy;
473 struct tk_read_base *tkr = &tk->tkr_mono;
475 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
476 cycles_at_suspend = tk_clock_read(tkr);
477 tkr_dummy.clock = &dummy_clock;
478 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
481 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
482 tkr_dummy.clock = &dummy_clock;
483 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
486 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
488 static inline void update_vsyscall(struct timekeeper *tk)
490 struct timespec xt, wm;
492 xt = timespec64_to_timespec(tk_xtime(tk));
493 wm = timespec64_to_timespec(tk->wall_to_monotonic);
494 update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult,
495 tk->tkr_mono.cycle_last);
498 static inline void old_vsyscall_fixup(struct timekeeper *tk)
503 * Store only full nanoseconds into xtime_nsec after rounding
504 * it up and add the remainder to the error difference.
505 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
506 * by truncating the remainder in vsyscalls. However, it causes
507 * additional work to be done in timekeeping_adjust(). Once
508 * the vsyscall implementations are converted to use xtime_nsec
509 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
510 * users are removed, this can be killed.
512 remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1);
513 if (remainder != 0) {
514 tk->tkr_mono.xtime_nsec -= remainder;
515 tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift;
516 tk->ntp_error += remainder << tk->ntp_error_shift;
517 tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift;
521 #define old_vsyscall_fixup(tk)
524 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
526 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
528 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
532 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
534 int pvclock_gtod_register_notifier(struct notifier_block *nb)
536 struct timekeeper *tk = &tk_core.timekeeper;
540 raw_spin_lock_irqsave(&timekeeper_lock, flags);
541 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
542 update_pvclock_gtod(tk, true);
543 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
547 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
550 * pvclock_gtod_unregister_notifier - unregister a pvclock
551 * timedata update listener
553 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
558 raw_spin_lock_irqsave(&timekeeper_lock, flags);
559 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
560 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
564 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
567 * tk_update_leap_state - helper to update the next_leap_ktime
569 static inline void tk_update_leap_state(struct timekeeper *tk)
571 tk->next_leap_ktime = ntp_get_next_leap();
572 if (tk->next_leap_ktime.tv64 != KTIME_MAX)
573 /* Convert to monotonic time */
574 tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
578 * Update the ktime_t based scalar nsec members of the timekeeper
580 static inline void tk_update_ktime_data(struct timekeeper *tk)
586 * The xtime based monotonic readout is:
587 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
588 * The ktime based monotonic readout is:
589 * nsec = base_mono + now();
590 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
592 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
593 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
594 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
596 /* Update the monotonic raw base */
597 tk->tkr_raw.base = timespec64_to_ktime(tk->raw_time);
600 * The sum of the nanoseconds portions of xtime and
601 * wall_to_monotonic can be greater/equal one second. Take
602 * this into account before updating tk->ktime_sec.
604 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
605 if (nsec >= NSEC_PER_SEC)
607 tk->ktime_sec = seconds;
610 /* must hold timekeeper_lock */
611 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
613 if (action & TK_CLEAR_NTP) {
618 tk_update_leap_state(tk);
619 tk_update_ktime_data(tk);
622 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
624 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
625 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
627 if (action & TK_CLOCK_WAS_SET)
628 tk->clock_was_set_seq++;
630 * The mirroring of the data to the shadow-timekeeper needs
631 * to happen last here to ensure we don't over-write the
632 * timekeeper structure on the next update with stale data
634 if (action & TK_MIRROR)
635 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
636 sizeof(tk_core.timekeeper));
640 * timekeeping_forward_now - update clock to the current time
642 * Forward the current clock to update its state since the last call to
643 * update_wall_time(). This is useful before significant clock changes,
644 * as it avoids having to deal with this time offset explicitly.
646 static void timekeeping_forward_now(struct timekeeper *tk)
648 cycle_t cycle_now, delta;
651 cycle_now = tk_clock_read(&tk->tkr_mono);
652 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
653 tk->tkr_mono.cycle_last = cycle_now;
654 tk->tkr_raw.cycle_last = cycle_now;
656 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
658 /* If arch requires, add in get_arch_timeoffset() */
659 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
661 tk_normalize_xtime(tk);
663 nsec = clocksource_cyc2ns(delta, tk->tkr_raw.mult, tk->tkr_raw.shift);
664 timespec64_add_ns(&tk->raw_time, nsec);
668 * __getnstimeofday64 - Returns the time of day in a timespec64.
669 * @ts: pointer to the timespec to be set
671 * Updates the time of day in the timespec.
672 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
674 int __getnstimeofday64(struct timespec64 *ts)
676 struct timekeeper *tk = &tk_core.timekeeper;
681 seq = read_seqcount_begin(&tk_core.seq);
683 ts->tv_sec = tk->xtime_sec;
684 nsecs = timekeeping_get_ns(&tk->tkr_mono);
686 } while (read_seqcount_retry(&tk_core.seq, seq));
689 timespec64_add_ns(ts, nsecs);
692 * Do not bail out early, in case there were callers still using
693 * the value, even in the face of the WARN_ON.
695 if (unlikely(timekeeping_suspended))
699 EXPORT_SYMBOL(__getnstimeofday64);
702 * getnstimeofday64 - Returns the time of day in a timespec64.
703 * @ts: pointer to the timespec64 to be set
705 * Returns the time of day in a timespec64 (WARN if suspended).
707 void getnstimeofday64(struct timespec64 *ts)
709 WARN_ON(__getnstimeofday64(ts));
711 EXPORT_SYMBOL(getnstimeofday64);
713 ktime_t ktime_get(void)
715 struct timekeeper *tk = &tk_core.timekeeper;
720 WARN_ON(timekeeping_suspended);
723 seq = read_seqcount_begin(&tk_core.seq);
724 base = tk->tkr_mono.base;
725 nsecs = timekeeping_get_ns(&tk->tkr_mono);
727 } while (read_seqcount_retry(&tk_core.seq, seq));
729 return ktime_add_ns(base, nsecs);
731 EXPORT_SYMBOL_GPL(ktime_get);
733 u32 ktime_get_resolution_ns(void)
735 struct timekeeper *tk = &tk_core.timekeeper;
739 WARN_ON(timekeeping_suspended);
742 seq = read_seqcount_begin(&tk_core.seq);
743 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
744 } while (read_seqcount_retry(&tk_core.seq, seq));
748 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
750 static ktime_t *offsets[TK_OFFS_MAX] = {
751 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
752 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
753 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
756 ktime_t ktime_get_with_offset(enum tk_offsets offs)
758 struct timekeeper *tk = &tk_core.timekeeper;
760 ktime_t base, *offset = offsets[offs];
763 WARN_ON(timekeeping_suspended);
766 seq = read_seqcount_begin(&tk_core.seq);
767 base = ktime_add(tk->tkr_mono.base, *offset);
768 nsecs = timekeeping_get_ns(&tk->tkr_mono);
770 } while (read_seqcount_retry(&tk_core.seq, seq));
772 return ktime_add_ns(base, nsecs);
775 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
778 * ktime_mono_to_any() - convert mononotic time to any other time
779 * @tmono: time to convert.
780 * @offs: which offset to use
782 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
784 ktime_t *offset = offsets[offs];
789 seq = read_seqcount_begin(&tk_core.seq);
790 tconv = ktime_add(tmono, *offset);
791 } while (read_seqcount_retry(&tk_core.seq, seq));
795 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
798 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
800 ktime_t ktime_get_raw(void)
802 struct timekeeper *tk = &tk_core.timekeeper;
808 seq = read_seqcount_begin(&tk_core.seq);
809 base = tk->tkr_raw.base;
810 nsecs = timekeeping_get_ns(&tk->tkr_raw);
812 } while (read_seqcount_retry(&tk_core.seq, seq));
814 return ktime_add_ns(base, nsecs);
816 EXPORT_SYMBOL_GPL(ktime_get_raw);
819 * ktime_get_ts64 - get the monotonic clock in timespec64 format
820 * @ts: pointer to timespec variable
822 * The function calculates the monotonic clock from the realtime
823 * clock and the wall_to_monotonic offset and stores the result
824 * in normalized timespec64 format in the variable pointed to by @ts.
826 void ktime_get_ts64(struct timespec64 *ts)
828 struct timekeeper *tk = &tk_core.timekeeper;
829 struct timespec64 tomono;
833 WARN_ON(timekeeping_suspended);
836 seq = read_seqcount_begin(&tk_core.seq);
837 ts->tv_sec = tk->xtime_sec;
838 nsec = timekeeping_get_ns(&tk->tkr_mono);
839 tomono = tk->wall_to_monotonic;
841 } while (read_seqcount_retry(&tk_core.seq, seq));
843 ts->tv_sec += tomono.tv_sec;
845 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
847 EXPORT_SYMBOL_GPL(ktime_get_ts64);
850 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
852 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
853 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
854 * works on both 32 and 64 bit systems. On 32 bit systems the readout
855 * covers ~136 years of uptime which should be enough to prevent
856 * premature wrap arounds.
858 time64_t ktime_get_seconds(void)
860 struct timekeeper *tk = &tk_core.timekeeper;
862 WARN_ON(timekeeping_suspended);
863 return tk->ktime_sec;
865 EXPORT_SYMBOL_GPL(ktime_get_seconds);
868 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
870 * Returns the wall clock seconds since 1970. This replaces the
871 * get_seconds() interface which is not y2038 safe on 32bit systems.
873 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
874 * 32bit systems the access must be protected with the sequence
875 * counter to provide "atomic" access to the 64bit tk->xtime_sec
878 time64_t ktime_get_real_seconds(void)
880 struct timekeeper *tk = &tk_core.timekeeper;
884 if (IS_ENABLED(CONFIG_64BIT))
885 return tk->xtime_sec;
888 seq = read_seqcount_begin(&tk_core.seq);
889 seconds = tk->xtime_sec;
891 } while (read_seqcount_retry(&tk_core.seq, seq));
895 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
898 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
899 * but without the sequence counter protect. This internal function
900 * is called just when timekeeping lock is already held.
902 time64_t __ktime_get_real_seconds(void)
904 struct timekeeper *tk = &tk_core.timekeeper;
906 return tk->xtime_sec;
910 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
911 * @systime_snapshot: pointer to struct receiving the system time snapshot
913 void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
915 struct timekeeper *tk = &tk_core.timekeeper;
923 WARN_ON_ONCE(timekeeping_suspended);
926 seq = read_seqcount_begin(&tk_core.seq);
927 now = tk_clock_read(&tk->tkr_mono);
928 systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
929 systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
930 base_real = ktime_add(tk->tkr_mono.base,
931 tk_core.timekeeper.offs_real);
932 base_raw = tk->tkr_raw.base;
933 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
934 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
935 } while (read_seqcount_retry(&tk_core.seq, seq));
937 systime_snapshot->cycles = now;
938 systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
939 systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
941 EXPORT_SYMBOL_GPL(ktime_get_snapshot);
943 /* Scale base by mult/div checking for overflow */
944 static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
948 tmp = div64_u64_rem(*base, div, &rem);
950 if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
951 ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
955 rem = div64_u64(rem * mult, div);
961 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
962 * @history: Snapshot representing start of history
963 * @partial_history_cycles: Cycle offset into history (fractional part)
964 * @total_history_cycles: Total history length in cycles
965 * @discontinuity: True indicates clock was set on history period
966 * @ts: Cross timestamp that should be adjusted using
967 * partial/total ratio
969 * Helper function used by get_device_system_crosststamp() to correct the
970 * crosstimestamp corresponding to the start of the current interval to the
971 * system counter value (timestamp point) provided by the driver. The
972 * total_history_* quantities are the total history starting at the provided
973 * reference point and ending at the start of the current interval. The cycle
974 * count between the driver timestamp point and the start of the current
975 * interval is partial_history_cycles.
977 static int adjust_historical_crosststamp(struct system_time_snapshot *history,
978 cycle_t partial_history_cycles,
979 cycle_t total_history_cycles,
981 struct system_device_crosststamp *ts)
983 struct timekeeper *tk = &tk_core.timekeeper;
984 u64 corr_raw, corr_real;
988 if (total_history_cycles == 0 || partial_history_cycles == 0)
991 /* Interpolate shortest distance from beginning or end of history */
992 interp_forward = partial_history_cycles > total_history_cycles/2 ?
994 partial_history_cycles = interp_forward ?
995 total_history_cycles - partial_history_cycles :
996 partial_history_cycles;
999 * Scale the monotonic raw time delta by:
1000 * partial_history_cycles / total_history_cycles
1002 corr_raw = (u64)ktime_to_ns(
1003 ktime_sub(ts->sys_monoraw, history->raw));
1004 ret = scale64_check_overflow(partial_history_cycles,
1005 total_history_cycles, &corr_raw);
1010 * If there is a discontinuity in the history, scale monotonic raw
1012 * mult(real)/mult(raw) yielding the realtime correction
1013 * Otherwise, calculate the realtime correction similar to monotonic
1016 if (discontinuity) {
1017 corr_real = mul_u64_u32_div
1018 (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1020 corr_real = (u64)ktime_to_ns(
1021 ktime_sub(ts->sys_realtime, history->real));
1022 ret = scale64_check_overflow(partial_history_cycles,
1023 total_history_cycles, &corr_real);
1028 /* Fixup monotonic raw and real time time values */
1029 if (interp_forward) {
1030 ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1031 ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1033 ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1034 ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1041 * cycle_between - true if test occurs chronologically between before and after
1043 static bool cycle_between(cycle_t before, cycle_t test, cycle_t after)
1045 if (test > before && test < after)
1047 if (test < before && before > after)
1053 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1054 * @get_time_fn: Callback to get simultaneous device time and
1055 * system counter from the device driver
1056 * @ctx: Context passed to get_time_fn()
1057 * @history_begin: Historical reference point used to interpolate system
1058 * time when counter provided by the driver is before the current interval
1059 * @xtstamp: Receives simultaneously captured system and device time
1061 * Reads a timestamp from a device and correlates it to system time
1063 int get_device_system_crosststamp(int (*get_time_fn)
1064 (ktime_t *device_time,
1065 struct system_counterval_t *sys_counterval,
1068 struct system_time_snapshot *history_begin,
1069 struct system_device_crosststamp *xtstamp)
1071 struct system_counterval_t system_counterval;
1072 struct timekeeper *tk = &tk_core.timekeeper;
1073 cycle_t cycles, now, interval_start;
1074 unsigned int clock_was_set_seq = 0;
1075 ktime_t base_real, base_raw;
1076 s64 nsec_real, nsec_raw;
1077 u8 cs_was_changed_seq;
1083 seq = read_seqcount_begin(&tk_core.seq);
1085 * Try to synchronously capture device time and a system
1086 * counter value calling back into the device driver
1088 ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1093 * Verify that the clocksource associated with the captured
1094 * system counter value is the same as the currently installed
1095 * timekeeper clocksource
1097 if (tk->tkr_mono.clock != system_counterval.cs)
1099 cycles = system_counterval.cycles;
1102 * Check whether the system counter value provided by the
1103 * device driver is on the current timekeeping interval.
1105 now = tk_clock_read(&tk->tkr_mono);
1106 interval_start = tk->tkr_mono.cycle_last;
1107 if (!cycle_between(interval_start, cycles, now)) {
1108 clock_was_set_seq = tk->clock_was_set_seq;
1109 cs_was_changed_seq = tk->cs_was_changed_seq;
1110 cycles = interval_start;
1116 base_real = ktime_add(tk->tkr_mono.base,
1117 tk_core.timekeeper.offs_real);
1118 base_raw = tk->tkr_raw.base;
1120 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1121 system_counterval.cycles);
1122 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1123 system_counterval.cycles);
1124 } while (read_seqcount_retry(&tk_core.seq, seq));
1126 xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1127 xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1130 * Interpolate if necessary, adjusting back from the start of the
1134 cycle_t partial_history_cycles, total_history_cycles;
1138 * Check that the counter value occurs after the provided
1139 * history reference and that the history doesn't cross a
1140 * clocksource change
1142 if (!history_begin ||
1143 !cycle_between(history_begin->cycles,
1144 system_counterval.cycles, cycles) ||
1145 history_begin->cs_was_changed_seq != cs_was_changed_seq)
1147 partial_history_cycles = cycles - system_counterval.cycles;
1148 total_history_cycles = cycles - history_begin->cycles;
1150 history_begin->clock_was_set_seq != clock_was_set_seq;
1152 ret = adjust_historical_crosststamp(history_begin,
1153 partial_history_cycles,
1154 total_history_cycles,
1155 discontinuity, xtstamp);
1162 EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1165 * do_gettimeofday - Returns the time of day in a timeval
1166 * @tv: pointer to the timeval to be set
1168 * NOTE: Users should be converted to using getnstimeofday()
1170 void do_gettimeofday(struct timeval *tv)
1172 struct timespec64 now;
1174 getnstimeofday64(&now);
1175 tv->tv_sec = now.tv_sec;
1176 tv->tv_usec = now.tv_nsec/1000;
1178 EXPORT_SYMBOL(do_gettimeofday);
1181 * do_settimeofday64 - Sets the time of day.
1182 * @ts: pointer to the timespec64 variable containing the new time
1184 * Sets the time of day to the new time and update NTP and notify hrtimers
1186 int do_settimeofday64(const struct timespec64 *ts)
1188 struct timekeeper *tk = &tk_core.timekeeper;
1189 struct timespec64 ts_delta, xt;
1190 unsigned long flags;
1193 if (!timespec64_valid_strict(ts))
1196 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1197 write_seqcount_begin(&tk_core.seq);
1199 timekeeping_forward_now(tk);
1202 ts_delta = timespec64_sub(*ts, xt);
1204 if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1209 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1211 tk_set_xtime(tk, ts);
1213 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1215 write_seqcount_end(&tk_core.seq);
1216 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1218 /* signal hrtimers about time change */
1223 EXPORT_SYMBOL(do_settimeofday64);
1226 * timekeeping_inject_offset - Adds or subtracts from the current time.
1227 * @tv: pointer to the timespec variable containing the offset
1229 * Adds or subtracts an offset value from the current time.
1231 int timekeeping_inject_offset(struct timespec *ts)
1233 struct timekeeper *tk = &tk_core.timekeeper;
1234 unsigned long flags;
1235 struct timespec64 ts64, tmp;
1238 if (!timespec_inject_offset_valid(ts))
1241 ts64 = timespec_to_timespec64(*ts);
1243 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1244 write_seqcount_begin(&tk_core.seq);
1246 timekeeping_forward_now(tk);
1248 /* Make sure the proposed value is valid */
1249 tmp = timespec64_add(tk_xtime(tk), ts64);
1250 if (timespec64_compare(&tk->wall_to_monotonic, &ts64) > 0 ||
1251 !timespec64_valid_strict(&tmp)) {
1256 tk_xtime_add(tk, &ts64);
1257 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
1259 error: /* even if we error out, we forwarded the time, so call update */
1260 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1262 write_seqcount_end(&tk_core.seq);
1263 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1265 /* signal hrtimers about time change */
1270 EXPORT_SYMBOL(timekeeping_inject_offset);
1274 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
1277 s32 timekeeping_get_tai_offset(void)
1279 struct timekeeper *tk = &tk_core.timekeeper;
1284 seq = read_seqcount_begin(&tk_core.seq);
1285 ret = tk->tai_offset;
1286 } while (read_seqcount_retry(&tk_core.seq, seq));
1292 * __timekeeping_set_tai_offset - Lock free worker function
1295 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1297 tk->tai_offset = tai_offset;
1298 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1302 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
1305 void timekeeping_set_tai_offset(s32 tai_offset)
1307 struct timekeeper *tk = &tk_core.timekeeper;
1308 unsigned long flags;
1310 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1311 write_seqcount_begin(&tk_core.seq);
1312 __timekeeping_set_tai_offset(tk, tai_offset);
1313 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1314 write_seqcount_end(&tk_core.seq);
1315 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1320 * change_clocksource - Swaps clocksources if a new one is available
1322 * Accumulates current time interval and initializes new clocksource
1324 static int change_clocksource(void *data)
1326 struct timekeeper *tk = &tk_core.timekeeper;
1327 struct clocksource *new, *old;
1328 unsigned long flags;
1330 new = (struct clocksource *) data;
1332 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1333 write_seqcount_begin(&tk_core.seq);
1335 timekeeping_forward_now(tk);
1337 * If the cs is in module, get a module reference. Succeeds
1338 * for built-in code (owner == NULL) as well.
1340 if (try_module_get(new->owner)) {
1341 if (!new->enable || new->enable(new) == 0) {
1342 old = tk->tkr_mono.clock;
1343 tk_setup_internals(tk, new);
1346 module_put(old->owner);
1348 module_put(new->owner);
1351 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1353 write_seqcount_end(&tk_core.seq);
1354 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1360 * timekeeping_notify - Install a new clock source
1361 * @clock: pointer to the clock source
1363 * This function is called from clocksource.c after a new, better clock
1364 * source has been registered. The caller holds the clocksource_mutex.
1366 int timekeeping_notify(struct clocksource *clock)
1368 struct timekeeper *tk = &tk_core.timekeeper;
1370 if (tk->tkr_mono.clock == clock)
1372 stop_machine(change_clocksource, clock, NULL);
1373 tick_clock_notify();
1374 return tk->tkr_mono.clock == clock ? 0 : -1;
1378 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1379 * @ts: pointer to the timespec64 to be set
1381 * Returns the raw monotonic time (completely un-modified by ntp)
1383 void getrawmonotonic64(struct timespec64 *ts)
1385 struct timekeeper *tk = &tk_core.timekeeper;
1386 struct timespec64 ts64;
1391 seq = read_seqcount_begin(&tk_core.seq);
1392 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1393 ts64 = tk->raw_time;
1395 } while (read_seqcount_retry(&tk_core.seq, seq));
1397 timespec64_add_ns(&ts64, nsecs);
1400 EXPORT_SYMBOL(getrawmonotonic64);
1404 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1406 int timekeeping_valid_for_hres(void)
1408 struct timekeeper *tk = &tk_core.timekeeper;
1413 seq = read_seqcount_begin(&tk_core.seq);
1415 ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1417 } while (read_seqcount_retry(&tk_core.seq, seq));
1423 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1425 u64 timekeeping_max_deferment(void)
1427 struct timekeeper *tk = &tk_core.timekeeper;
1432 seq = read_seqcount_begin(&tk_core.seq);
1434 ret = tk->tkr_mono.clock->max_idle_ns;
1436 } while (read_seqcount_retry(&tk_core.seq, seq));
1442 * read_persistent_clock - Return time from the persistent clock.
1444 * Weak dummy function for arches that do not yet support it.
1445 * Reads the time from the battery backed persistent clock.
1446 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1448 * XXX - Do be sure to remove it once all arches implement it.
1450 void __weak read_persistent_clock(struct timespec *ts)
1456 void __weak read_persistent_clock64(struct timespec64 *ts64)
1460 read_persistent_clock(&ts);
1461 *ts64 = timespec_to_timespec64(ts);
1465 * read_boot_clock64 - Return time of the system start.
1467 * Weak dummy function for arches that do not yet support it.
1468 * Function to read the exact time the system has been started.
1469 * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported.
1471 * XXX - Do be sure to remove it once all arches implement it.
1473 void __weak read_boot_clock64(struct timespec64 *ts)
1479 /* Flag for if timekeeping_resume() has injected sleeptime */
1480 static bool sleeptime_injected;
1482 /* Flag for if there is a persistent clock on this platform */
1483 static bool persistent_clock_exists;
1486 * timekeeping_init - Initializes the clocksource and common timekeeping values
1488 void __init timekeeping_init(void)
1490 struct timekeeper *tk = &tk_core.timekeeper;
1491 struct clocksource *clock;
1492 unsigned long flags;
1493 struct timespec64 now, boot, tmp;
1495 read_persistent_clock64(&now);
1496 if (!timespec64_valid_strict(&now)) {
1497 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1498 " Check your CMOS/BIOS settings.\n");
1501 } else if (now.tv_sec || now.tv_nsec)
1502 persistent_clock_exists = true;
1504 read_boot_clock64(&boot);
1505 if (!timespec64_valid_strict(&boot)) {
1506 pr_warn("WARNING: Boot clock returned invalid value!\n"
1507 " Check your CMOS/BIOS settings.\n");
1512 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1513 write_seqcount_begin(&tk_core.seq);
1516 clock = clocksource_default_clock();
1518 clock->enable(clock);
1519 tk_setup_internals(tk, clock);
1521 tk_set_xtime(tk, &now);
1522 tk->raw_time.tv_sec = 0;
1523 tk->raw_time.tv_nsec = 0;
1524 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1525 boot = tk_xtime(tk);
1527 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1528 tk_set_wall_to_mono(tk, tmp);
1530 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1532 write_seqcount_end(&tk_core.seq);
1533 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1536 /* time in seconds when suspend began for persistent clock */
1537 static struct timespec64 timekeeping_suspend_time;
1540 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1541 * @delta: pointer to a timespec delta value
1543 * Takes a timespec offset measuring a suspend interval and properly
1544 * adds the sleep offset to the timekeeping variables.
1546 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1547 struct timespec64 *delta)
1549 if (!timespec64_valid_strict(delta)) {
1550 printk_deferred(KERN_WARNING
1551 "__timekeeping_inject_sleeptime: Invalid "
1552 "sleep delta value!\n");
1555 tk_xtime_add(tk, delta);
1556 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1557 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1558 tk_debug_account_sleep_time(delta);
1561 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1563 * We have three kinds of time sources to use for sleep time
1564 * injection, the preference order is:
1565 * 1) non-stop clocksource
1566 * 2) persistent clock (ie: RTC accessible when irqs are off)
1569 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1570 * If system has neither 1) nor 2), 3) will be used finally.
1573 * If timekeeping has injected sleeptime via either 1) or 2),
1574 * 3) becomes needless, so in this case we don't need to call
1575 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1578 bool timekeeping_rtc_skipresume(void)
1580 return sleeptime_injected;
1584 * 1) can be determined whether to use or not only when doing
1585 * timekeeping_resume() which is invoked after rtc_suspend(),
1586 * so we can't skip rtc_suspend() surely if system has 1).
1588 * But if system has 2), 2) will definitely be used, so in this
1589 * case we don't need to call rtc_suspend(), and this is what
1590 * timekeeping_rtc_skipsuspend() means.
1592 bool timekeeping_rtc_skipsuspend(void)
1594 return persistent_clock_exists;
1598 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1599 * @delta: pointer to a timespec64 delta value
1601 * This hook is for architectures that cannot support read_persistent_clock64
1602 * because their RTC/persistent clock is only accessible when irqs are enabled.
1603 * and also don't have an effective nonstop clocksource.
1605 * This function should only be called by rtc_resume(), and allows
1606 * a suspend offset to be injected into the timekeeping values.
1608 void timekeeping_inject_sleeptime64(struct timespec64 *delta)
1610 struct timekeeper *tk = &tk_core.timekeeper;
1611 unsigned long flags;
1613 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1614 write_seqcount_begin(&tk_core.seq);
1616 timekeeping_forward_now(tk);
1618 __timekeeping_inject_sleeptime(tk, delta);
1620 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1622 write_seqcount_end(&tk_core.seq);
1623 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1625 /* signal hrtimers about time change */
1631 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1633 void timekeeping_resume(void)
1635 struct timekeeper *tk = &tk_core.timekeeper;
1636 struct clocksource *clock = tk->tkr_mono.clock;
1637 unsigned long flags;
1638 struct timespec64 ts_new, ts_delta;
1639 cycle_t cycle_now, cycle_delta;
1641 sleeptime_injected = false;
1642 read_persistent_clock64(&ts_new);
1644 clockevents_resume();
1645 clocksource_resume();
1647 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1648 write_seqcount_begin(&tk_core.seq);
1651 * After system resumes, we need to calculate the suspended time and
1652 * compensate it for the OS time. There are 3 sources that could be
1653 * used: Nonstop clocksource during suspend, persistent clock and rtc
1656 * One specific platform may have 1 or 2 or all of them, and the
1657 * preference will be:
1658 * suspend-nonstop clocksource -> persistent clock -> rtc
1659 * The less preferred source will only be tried if there is no better
1660 * usable source. The rtc part is handled separately in rtc core code.
1662 cycle_now = tk_clock_read(&tk->tkr_mono);
1663 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1664 cycle_now > tk->tkr_mono.cycle_last) {
1665 u64 num, max = ULLONG_MAX;
1666 u32 mult = clock->mult;
1667 u32 shift = clock->shift;
1670 cycle_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
1674 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1675 * suspended time is too long. In that case we need do the
1676 * 64 bits math carefully
1679 if (cycle_delta > max) {
1680 num = div64_u64(cycle_delta, max);
1681 nsec = (((u64) max * mult) >> shift) * num;
1682 cycle_delta -= num * max;
1684 nsec += ((u64) cycle_delta * mult) >> shift;
1686 ts_delta = ns_to_timespec64(nsec);
1687 sleeptime_injected = true;
1688 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1689 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1690 sleeptime_injected = true;
1693 if (sleeptime_injected)
1694 __timekeeping_inject_sleeptime(tk, &ts_delta);
1696 /* Re-base the last cycle value */
1697 tk->tkr_mono.cycle_last = cycle_now;
1698 tk->tkr_raw.cycle_last = cycle_now;
1701 timekeeping_suspended = 0;
1702 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1703 write_seqcount_end(&tk_core.seq);
1704 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1706 touch_softlockup_watchdog();
1712 int timekeeping_suspend(void)
1714 struct timekeeper *tk = &tk_core.timekeeper;
1715 unsigned long flags;
1716 struct timespec64 delta, delta_delta;
1717 static struct timespec64 old_delta;
1719 read_persistent_clock64(&timekeeping_suspend_time);
1722 * On some systems the persistent_clock can not be detected at
1723 * timekeeping_init by its return value, so if we see a valid
1724 * value returned, update the persistent_clock_exists flag.
1726 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1727 persistent_clock_exists = true;
1729 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1730 write_seqcount_begin(&tk_core.seq);
1731 timekeeping_forward_now(tk);
1732 timekeeping_suspended = 1;
1734 if (persistent_clock_exists) {
1736 * To avoid drift caused by repeated suspend/resumes,
1737 * which each can add ~1 second drift error,
1738 * try to compensate so the difference in system time
1739 * and persistent_clock time stays close to constant.
1741 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1742 delta_delta = timespec64_sub(delta, old_delta);
1743 if (abs(delta_delta.tv_sec) >= 2) {
1745 * if delta_delta is too large, assume time correction
1746 * has occurred and set old_delta to the current delta.
1750 /* Otherwise try to adjust old_system to compensate */
1751 timekeeping_suspend_time =
1752 timespec64_add(timekeeping_suspend_time, delta_delta);
1756 timekeeping_update(tk, TK_MIRROR);
1757 halt_fast_timekeeper(tk);
1758 write_seqcount_end(&tk_core.seq);
1759 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1762 clocksource_suspend();
1763 clockevents_suspend();
1768 /* sysfs resume/suspend bits for timekeeping */
1769 static struct syscore_ops timekeeping_syscore_ops = {
1770 .resume = timekeeping_resume,
1771 .suspend = timekeeping_suspend,
1774 static int __init timekeeping_init_ops(void)
1776 register_syscore_ops(&timekeeping_syscore_ops);
1779 device_initcall(timekeeping_init_ops);
1782 * Apply a multiplier adjustment to the timekeeper
1784 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1789 s64 interval = tk->cycle_interval;
1793 mult_adj = -mult_adj;
1794 interval = -interval;
1797 mult_adj <<= adj_scale;
1798 interval <<= adj_scale;
1799 offset <<= adj_scale;
1802 * So the following can be confusing.
1804 * To keep things simple, lets assume mult_adj == 1 for now.
1806 * When mult_adj != 1, remember that the interval and offset values
1807 * have been appropriately scaled so the math is the same.
1809 * The basic idea here is that we're increasing the multiplier
1810 * by one, this causes the xtime_interval to be incremented by
1811 * one cycle_interval. This is because:
1812 * xtime_interval = cycle_interval * mult
1813 * So if mult is being incremented by one:
1814 * xtime_interval = cycle_interval * (mult + 1)
1816 * xtime_interval = (cycle_interval * mult) + cycle_interval
1817 * Which can be shortened to:
1818 * xtime_interval += cycle_interval
1820 * So offset stores the non-accumulated cycles. Thus the current
1821 * time (in shifted nanoseconds) is:
1822 * now = (offset * adj) + xtime_nsec
1823 * Now, even though we're adjusting the clock frequency, we have
1824 * to keep time consistent. In other words, we can't jump back
1825 * in time, and we also want to avoid jumping forward in time.
1827 * So given the same offset value, we need the time to be the same
1828 * both before and after the freq adjustment.
1829 * now = (offset * adj_1) + xtime_nsec_1
1830 * now = (offset * adj_2) + xtime_nsec_2
1832 * (offset * adj_1) + xtime_nsec_1 =
1833 * (offset * adj_2) + xtime_nsec_2
1837 * (offset * adj_1) + xtime_nsec_1 =
1838 * (offset * (adj_1+1)) + xtime_nsec_2
1839 * (offset * adj_1) + xtime_nsec_1 =
1840 * (offset * adj_1) + offset + xtime_nsec_2
1841 * Canceling the sides:
1842 * xtime_nsec_1 = offset + xtime_nsec_2
1844 * xtime_nsec_2 = xtime_nsec_1 - offset
1845 * Which simplfies to:
1846 * xtime_nsec -= offset
1848 * XXX - TODO: Doc ntp_error calculation.
1850 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1851 /* NTP adjustment caused clocksource mult overflow */
1856 tk->tkr_mono.mult += mult_adj;
1857 tk->xtime_interval += interval;
1858 tk->tkr_mono.xtime_nsec -= offset;
1859 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1863 * Calculate the multiplier adjustment needed to match the frequency
1866 static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
1869 s64 interval = tk->cycle_interval;
1870 s64 xinterval = tk->xtime_interval;
1871 u32 base = tk->tkr_mono.clock->mult;
1872 u32 max = tk->tkr_mono.clock->maxadj;
1873 u32 cur_adj = tk->tkr_mono.mult;
1878 /* Remove any current error adj from freq calculation */
1879 if (tk->ntp_err_mult)
1880 xinterval -= tk->cycle_interval;
1882 tk->ntp_tick = ntp_tick_length();
1884 /* Calculate current error per tick */
1885 tick_error = ntp_tick_length() >> tk->ntp_error_shift;
1886 tick_error -= (xinterval + tk->xtime_remainder);
1888 /* Don't worry about correcting it if its small */
1889 if (likely((tick_error >= 0) && (tick_error <= interval)))
1892 /* preserve the direction of correction */
1893 negative = (tick_error < 0);
1895 /* If any adjustment would pass the max, just return */
1896 if (negative && (cur_adj - 1) <= (base - max))
1898 if (!negative && (cur_adj + 1) >= (base + max))
1901 * Sort out the magnitude of the correction, but
1902 * avoid making so large a correction that we go
1903 * over the max adjustment.
1906 tick_error = abs(tick_error);
1907 while (tick_error > interval) {
1908 u32 adj = 1 << (adj_scale + 1);
1910 /* Check if adjustment gets us within 1 unit from the max */
1911 if (negative && (cur_adj - adj) <= (base - max))
1913 if (!negative && (cur_adj + adj) >= (base + max))
1920 /* scale the corrections */
1921 timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
1925 * Adjust the timekeeper's multiplier to the correct frequency
1926 * and also to reduce the accumulated error value.
1928 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1930 /* Correct for the current frequency error */
1931 timekeeping_freqadjust(tk, offset);
1933 /* Next make a small adjustment to fix any cumulative error */
1934 if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
1935 tk->ntp_err_mult = 1;
1936 timekeeping_apply_adjustment(tk, offset, 0, 0);
1937 } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
1938 /* Undo any existing error adjustment */
1939 timekeeping_apply_adjustment(tk, offset, 1, 0);
1940 tk->ntp_err_mult = 0;
1943 if (unlikely(tk->tkr_mono.clock->maxadj &&
1944 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1945 > tk->tkr_mono.clock->maxadj))) {
1946 printk_once(KERN_WARNING
1947 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1948 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1949 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1953 * It may be possible that when we entered this function, xtime_nsec
1954 * was very small. Further, if we're slightly speeding the clocksource
1955 * in the code above, its possible the required corrective factor to
1956 * xtime_nsec could cause it to underflow.
1958 * Now, since we already accumulated the second, cannot simply roll
1959 * the accumulated second back, since the NTP subsystem has been
1960 * notified via second_overflow. So instead we push xtime_nsec forward
1961 * by the amount we underflowed, and add that amount into the error.
1963 * We'll correct this error next time through this function, when
1964 * xtime_nsec is not as small.
1966 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1967 s64 neg = -(s64)tk->tkr_mono.xtime_nsec;
1968 tk->tkr_mono.xtime_nsec = 0;
1969 tk->ntp_error += neg << tk->ntp_error_shift;
1974 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1976 * Helper function that accumulates the nsecs greater than a second
1977 * from the xtime_nsec field to the xtime_secs field.
1978 * It also calls into the NTP code to handle leapsecond processing.
1981 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1983 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1984 unsigned int clock_set = 0;
1986 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1989 tk->tkr_mono.xtime_nsec -= nsecps;
1992 /* Figure out if its a leap sec and apply if needed */
1993 leap = second_overflow(tk->xtime_sec);
1994 if (unlikely(leap)) {
1995 struct timespec64 ts;
1997 tk->xtime_sec += leap;
2001 tk_set_wall_to_mono(tk,
2002 timespec64_sub(tk->wall_to_monotonic, ts));
2004 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
2006 clock_set = TK_CLOCK_WAS_SET;
2013 * logarithmic_accumulation - shifted accumulation of cycles
2015 * This functions accumulates a shifted interval of cycles into
2016 * into a shifted interval nanoseconds. Allows for O(log) accumulation
2019 * Returns the unconsumed cycles.
2021 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
2023 unsigned int *clock_set)
2025 cycle_t interval = tk->cycle_interval << shift;
2028 /* If the offset is smaller than a shifted interval, do nothing */
2029 if (offset < interval)
2032 /* Accumulate one shifted interval */
2034 tk->tkr_mono.cycle_last += interval;
2035 tk->tkr_raw.cycle_last += interval;
2037 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2038 *clock_set |= accumulate_nsecs_to_secs(tk);
2040 /* Accumulate raw time */
2041 tk->tkr_raw.xtime_nsec += (u64)tk->raw_time.tv_nsec << tk->tkr_raw.shift;
2042 tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2043 snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2044 while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2045 tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2046 tk->raw_time.tv_sec++;
2048 tk->raw_time.tv_nsec = tk->tkr_raw.xtime_nsec >> tk->tkr_raw.shift;
2049 tk->tkr_raw.xtime_nsec -= (u64)tk->raw_time.tv_nsec << tk->tkr_raw.shift;
2051 /* Accumulate error between NTP and clock interval */
2052 tk->ntp_error += tk->ntp_tick << shift;
2053 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2054 (tk->ntp_error_shift + shift);
2060 * update_wall_time - Uses the current clocksource to increment the wall time
2063 void update_wall_time(void)
2065 struct timekeeper *real_tk = &tk_core.timekeeper;
2066 struct timekeeper *tk = &shadow_timekeeper;
2068 int shift = 0, maxshift;
2069 unsigned int clock_set = 0;
2070 unsigned long flags;
2072 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2074 /* Make sure we're fully resumed: */
2075 if (unlikely(timekeeping_suspended))
2078 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2079 offset = real_tk->cycle_interval;
2081 offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2082 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2085 /* Check if there's really nothing to do */
2086 if (offset < real_tk->cycle_interval)
2089 /* Do some additional sanity checking */
2090 timekeeping_check_update(real_tk, offset);
2093 * With NO_HZ we may have to accumulate many cycle_intervals
2094 * (think "ticks") worth of time at once. To do this efficiently,
2095 * we calculate the largest doubling multiple of cycle_intervals
2096 * that is smaller than the offset. We then accumulate that
2097 * chunk in one go, and then try to consume the next smaller
2100 shift = ilog2(offset) - ilog2(tk->cycle_interval);
2101 shift = max(0, shift);
2102 /* Bound shift to one less than what overflows tick_length */
2103 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2104 shift = min(shift, maxshift);
2105 while (offset >= tk->cycle_interval) {
2106 offset = logarithmic_accumulation(tk, offset, shift,
2108 if (offset < tk->cycle_interval<<shift)
2112 /* correct the clock when NTP error is too big */
2113 timekeeping_adjust(tk, offset);
2116 * XXX This can be killed once everyone converts
2117 * to the new update_vsyscall.
2119 old_vsyscall_fixup(tk);
2122 * Finally, make sure that after the rounding
2123 * xtime_nsec isn't larger than NSEC_PER_SEC
2125 clock_set |= accumulate_nsecs_to_secs(tk);
2127 write_seqcount_begin(&tk_core.seq);
2129 * Update the real timekeeper.
2131 * We could avoid this memcpy by switching pointers, but that
2132 * requires changes to all other timekeeper usage sites as
2133 * well, i.e. move the timekeeper pointer getter into the
2134 * spinlocked/seqcount protected sections. And we trade this
2135 * memcpy under the tk_core.seq against one before we start
2138 timekeeping_update(tk, clock_set);
2139 memcpy(real_tk, tk, sizeof(*tk));
2140 /* The memcpy must come last. Do not put anything here! */
2141 write_seqcount_end(&tk_core.seq);
2143 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2145 /* Have to call _delayed version, since in irq context*/
2146 clock_was_set_delayed();
2150 * getboottime64 - Return the real time of system boot.
2151 * @ts: pointer to the timespec64 to be set
2153 * Returns the wall-time of boot in a timespec64.
2155 * This is based on the wall_to_monotonic offset and the total suspend
2156 * time. Calls to settimeofday will affect the value returned (which
2157 * basically means that however wrong your real time clock is at boot time,
2158 * you get the right time here).
2160 void getboottime64(struct timespec64 *ts)
2162 struct timekeeper *tk = &tk_core.timekeeper;
2163 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2165 *ts = ktime_to_timespec64(t);
2167 EXPORT_SYMBOL_GPL(getboottime64);
2169 unsigned long get_seconds(void)
2171 struct timekeeper *tk = &tk_core.timekeeper;
2173 return tk->xtime_sec;
2175 EXPORT_SYMBOL(get_seconds);
2177 struct timespec __current_kernel_time(void)
2179 struct timekeeper *tk = &tk_core.timekeeper;
2181 return timespec64_to_timespec(tk_xtime(tk));
2184 struct timespec64 current_kernel_time64(void)
2186 struct timekeeper *tk = &tk_core.timekeeper;
2187 struct timespec64 now;
2191 seq = read_seqcount_begin(&tk_core.seq);
2194 } while (read_seqcount_retry(&tk_core.seq, seq));
2198 EXPORT_SYMBOL(current_kernel_time64);
2200 struct timespec64 get_monotonic_coarse64(void)
2202 struct timekeeper *tk = &tk_core.timekeeper;
2203 struct timespec64 now, mono;
2207 seq = read_seqcount_begin(&tk_core.seq);
2210 mono = tk->wall_to_monotonic;
2211 } while (read_seqcount_retry(&tk_core.seq, seq));
2213 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
2214 now.tv_nsec + mono.tv_nsec);
2218 EXPORT_SYMBOL(get_monotonic_coarse64);
2221 * Must hold jiffies_lock
2223 void do_timer(unsigned long ticks)
2225 jiffies_64 += ticks;
2226 calc_global_load(ticks);
2230 * ktime_get_update_offsets_now - hrtimer helper
2231 * @cwsseq: pointer to check and store the clock was set sequence number
2232 * @offs_real: pointer to storage for monotonic -> realtime offset
2233 * @offs_boot: pointer to storage for monotonic -> boottime offset
2234 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2236 * Returns current monotonic time and updates the offsets if the
2237 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2240 * Called from hrtimer_interrupt() or retrigger_next_event()
2242 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2243 ktime_t *offs_boot, ktime_t *offs_tai)
2245 struct timekeeper *tk = &tk_core.timekeeper;
2251 seq = read_seqcount_begin(&tk_core.seq);
2253 base = tk->tkr_mono.base;
2254 nsecs = timekeeping_get_ns(&tk->tkr_mono);
2255 base = ktime_add_ns(base, nsecs);
2257 if (*cwsseq != tk->clock_was_set_seq) {
2258 *cwsseq = tk->clock_was_set_seq;
2259 *offs_real = tk->offs_real;
2260 *offs_boot = tk->offs_boot;
2261 *offs_tai = tk->offs_tai;
2264 /* Handle leapsecond insertion adjustments */
2265 if (unlikely(base.tv64 >= tk->next_leap_ktime.tv64))
2266 *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2268 } while (read_seqcount_retry(&tk_core.seq, seq));
2274 * random_get_entropy_fallback - Returns the raw clock source value,
2275 * used by random.c for platforms with no valid random_get_entropy().
2277 unsigned long random_get_entropy_fallback(void)
2279 struct tk_read_base *tkr = &tk_core.timekeeper.tkr_mono;
2280 struct clocksource *clock = READ_ONCE(tkr->clock);
2282 if (unlikely(timekeeping_suspended || !clock))
2284 return clock->read(clock);
2286 EXPORT_SYMBOL_GPL(random_get_entropy_fallback);
2289 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2291 int do_adjtimex(struct timex *txc)
2293 struct timekeeper *tk = &tk_core.timekeeper;
2294 unsigned long flags;
2295 struct timespec64 ts;
2299 /* Validate the data before disabling interrupts */
2300 ret = ntp_validate_timex(txc);
2304 if (txc->modes & ADJ_SETOFFSET) {
2305 struct timespec delta;
2306 delta.tv_sec = txc->time.tv_sec;
2307 delta.tv_nsec = txc->time.tv_usec;
2308 if (!(txc->modes & ADJ_NANO))
2309 delta.tv_nsec *= 1000;
2310 ret = timekeeping_inject_offset(&delta);
2315 getnstimeofday64(&ts);
2317 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2318 write_seqcount_begin(&tk_core.seq);
2320 orig_tai = tai = tk->tai_offset;
2321 ret = __do_adjtimex(txc, &ts, &tai);
2323 if (tai != orig_tai) {
2324 __timekeeping_set_tai_offset(tk, tai);
2325 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2327 tk_update_leap_state(tk);
2329 write_seqcount_end(&tk_core.seq);
2330 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2332 if (tai != orig_tai)
2335 ntp_notify_cmos_timer();
2340 #ifdef CONFIG_NTP_PPS
2342 * hardpps() - Accessor function to NTP __hardpps function
2344 void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2346 unsigned long flags;
2348 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2349 write_seqcount_begin(&tk_core.seq);
2351 __hardpps(phase_ts, raw_ts);
2353 write_seqcount_end(&tk_core.seq);
2354 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2356 EXPORT_SYMBOL(hardpps);
2360 * xtime_update() - advances the timekeeping infrastructure
2361 * @ticks: number of ticks, that have elapsed since the last call.
2363 * Must be called with interrupts disabled.
2365 void xtime_update(unsigned long ticks)
2367 write_seqlock(&jiffies_lock);
2369 write_sequnlock(&jiffies_lock);