2 * linux/kernel/time/timekeeping.c
4 * Kernel timekeeping code and accessor functions
6 * This code was moved from linux/kernel/timer.c.
7 * Please see that file for copyright and history logs.
11 #include <linux/timekeeper_internal.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include <linux/percpu.h>
15 #include <linux/init.h>
17 #include <linux/nmi.h>
18 #include <linux/sched.h>
19 #include <linux/sched/loadavg.h>
20 #include <linux/syscore_ops.h>
21 #include <linux/clocksource.h>
22 #include <linux/jiffies.h>
23 #include <linux/time.h>
24 #include <linux/tick.h>
25 #include <linux/stop_machine.h>
26 #include <linux/pvclock_gtod.h>
27 #include <linux/compiler.h>
29 #include "tick-internal.h"
30 #include "ntp_internal.h"
31 #include "timekeeping_internal.h"
33 #define TK_CLEAR_NTP (1 << 0)
34 #define TK_MIRROR (1 << 1)
35 #define TK_CLOCK_WAS_SET (1 << 2)
38 * The most important data for readout fits into a single 64 byte
43 struct timekeeper timekeeper;
44 } tk_core ____cacheline_aligned;
46 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
47 static struct timekeeper shadow_timekeeper;
50 * struct tk_fast - NMI safe timekeeper
51 * @seq: Sequence counter for protecting updates. The lowest bit
52 * is the index for the tk_read_base array
53 * @base: tk_read_base array. Access is indexed by the lowest bit of
56 * See @update_fast_timekeeper() below.
60 struct tk_read_base base[2];
63 static struct tk_fast tk_fast_mono ____cacheline_aligned;
64 static struct tk_fast tk_fast_raw ____cacheline_aligned;
66 /* flag for if timekeeping is suspended */
67 int __read_mostly timekeeping_suspended;
69 static inline void tk_normalize_xtime(struct timekeeper *tk)
71 while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
72 tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
77 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
81 ts.tv_sec = tk->xtime_sec;
82 ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
86 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
88 tk->xtime_sec = ts->tv_sec;
89 tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
92 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
94 tk->xtime_sec += ts->tv_sec;
95 tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
96 tk_normalize_xtime(tk);
99 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
101 struct timespec64 tmp;
104 * Verify consistency of: offset_real = -wall_to_monotonic
105 * before modifying anything
107 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
108 -tk->wall_to_monotonic.tv_nsec);
109 WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
110 tk->wall_to_monotonic = wtm;
111 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
112 tk->offs_real = timespec64_to_ktime(tmp);
113 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
116 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
118 tk->offs_boot = ktime_add(tk->offs_boot, delta);
122 * tk_clock_read - atomic clocksource read() helper
124 * This helper is necessary to use in the read paths because, while the
125 * seqlock ensures we don't return a bad value while structures are updated,
126 * it doesn't protect from potential crashes. There is the possibility that
127 * the tkr's clocksource may change between the read reference, and the
128 * clock reference passed to the read function. This can cause crashes if
129 * the wrong clocksource is passed to the wrong read function.
130 * This isn't necessary to use when holding the timekeeper_lock or doing
131 * a read of the fast-timekeeper tkrs (which is protected by its own locking
134 static inline u64 tk_clock_read(struct tk_read_base *tkr)
136 struct clocksource *clock = READ_ONCE(tkr->clock);
138 return clock->read(clock);
141 #ifdef CONFIG_DEBUG_TIMEKEEPING
142 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
144 static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
147 u64 max_cycles = tk->tkr_mono.clock->max_cycles;
148 const char *name = tk->tkr_mono.clock->name;
150 if (offset > max_cycles) {
151 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
152 offset, name, max_cycles);
153 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
155 if (offset > (max_cycles >> 1)) {
156 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
157 offset, name, max_cycles >> 1);
158 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
162 if (tk->underflow_seen) {
163 if (jiffies - tk->last_warning > WARNING_FREQ) {
164 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
165 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
166 printk_deferred(" Your kernel is probably still fine.\n");
167 tk->last_warning = jiffies;
169 tk->underflow_seen = 0;
172 if (tk->overflow_seen) {
173 if (jiffies - tk->last_warning > WARNING_FREQ) {
174 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
175 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
176 printk_deferred(" Your kernel is probably still fine.\n");
177 tk->last_warning = jiffies;
179 tk->overflow_seen = 0;
183 static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
185 struct timekeeper *tk = &tk_core.timekeeper;
186 u64 now, last, mask, max, delta;
190 * Since we're called holding a seqlock, the data may shift
191 * under us while we're doing the calculation. This can cause
192 * false positives, since we'd note a problem but throw the
193 * results away. So nest another seqlock here to atomically
194 * grab the points we are checking with.
197 seq = read_seqcount_begin(&tk_core.seq);
198 now = tk_clock_read(tkr);
199 last = tkr->cycle_last;
201 max = tkr->clock->max_cycles;
202 } while (read_seqcount_retry(&tk_core.seq, seq));
204 delta = clocksource_delta(now, last, mask);
207 * Try to catch underflows by checking if we are seeing small
208 * mask-relative negative values.
210 if (unlikely((~delta & mask) < (mask >> 3))) {
211 tk->underflow_seen = 1;
215 /* Cap delta value to the max_cycles values to avoid mult overflows */
216 if (unlikely(delta > max)) {
217 tk->overflow_seen = 1;
218 delta = tkr->clock->max_cycles;
224 static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
227 static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
229 u64 cycle_now, delta;
231 /* read clocksource */
232 cycle_now = tk_clock_read(tkr);
234 /* calculate the delta since the last update_wall_time */
235 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
242 * tk_setup_internals - Set up internals to use clocksource clock.
244 * @tk: The target timekeeper to setup.
245 * @clock: Pointer to clocksource.
247 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
248 * pair and interval request.
250 * Unless you're the timekeeping code, you should not be using this!
252 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
255 u64 tmp, ntpinterval;
256 struct clocksource *old_clock;
258 ++tk->cs_was_changed_seq;
259 old_clock = tk->tkr_mono.clock;
260 tk->tkr_mono.clock = clock;
261 tk->tkr_mono.mask = clock->mask;
262 tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
264 tk->tkr_raw.clock = clock;
265 tk->tkr_raw.mask = clock->mask;
266 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
268 /* Do the ns -> cycle conversion first, using original mult */
269 tmp = NTP_INTERVAL_LENGTH;
270 tmp <<= clock->shift;
272 tmp += clock->mult/2;
273 do_div(tmp, clock->mult);
277 interval = (u64) tmp;
278 tk->cycle_interval = interval;
280 /* Go back from cycles -> shifted ns */
281 tk->xtime_interval = interval * clock->mult;
282 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
283 tk->raw_interval = interval * clock->mult;
285 /* if changing clocks, convert xtime_nsec shift units */
287 int shift_change = clock->shift - old_clock->shift;
288 if (shift_change < 0)
289 tk->tkr_mono.xtime_nsec >>= -shift_change;
291 tk->tkr_mono.xtime_nsec <<= shift_change;
293 tk->tkr_raw.xtime_nsec = 0;
295 tk->tkr_mono.shift = clock->shift;
296 tk->tkr_raw.shift = clock->shift;
299 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
300 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
303 * The timekeeper keeps its own mult values for the currently
304 * active clocksource. These value will be adjusted via NTP
305 * to counteract clock drifting.
307 tk->tkr_mono.mult = clock->mult;
308 tk->tkr_raw.mult = clock->mult;
309 tk->ntp_err_mult = 0;
312 /* Timekeeper helper functions. */
314 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
315 static u32 default_arch_gettimeoffset(void) { return 0; }
316 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
318 static inline u32 arch_gettimeoffset(void) { return 0; }
321 static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr, u64 delta)
325 nsec = delta * tkr->mult + tkr->xtime_nsec;
328 /* If arch requires, add in get_arch_timeoffset() */
329 return nsec + arch_gettimeoffset();
332 static inline u64 timekeeping_get_ns(struct tk_read_base *tkr)
336 delta = timekeeping_get_delta(tkr);
337 return timekeeping_delta_to_ns(tkr, delta);
340 static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr, u64 cycles)
344 /* calculate the delta since the last update_wall_time */
345 delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
346 return timekeeping_delta_to_ns(tkr, delta);
350 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
351 * @tkr: Timekeeping readout base from which we take the update
353 * We want to use this from any context including NMI and tracing /
354 * instrumenting the timekeeping code itself.
356 * Employ the latch technique; see @raw_write_seqcount_latch.
358 * So if a NMI hits the update of base[0] then it will use base[1]
359 * which is still consistent. In the worst case this can result is a
360 * slightly wrong timestamp (a few nanoseconds). See
361 * @ktime_get_mono_fast_ns.
363 static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
365 struct tk_read_base *base = tkf->base;
367 /* Force readers off to base[1] */
368 raw_write_seqcount_latch(&tkf->seq);
371 memcpy(base, tkr, sizeof(*base));
373 /* Force readers back to base[0] */
374 raw_write_seqcount_latch(&tkf->seq);
377 memcpy(base + 1, base, sizeof(*base));
381 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
383 * This timestamp is not guaranteed to be monotonic across an update.
384 * The timestamp is calculated by:
386 * now = base_mono + clock_delta * slope
388 * So if the update lowers the slope, readers who are forced to the
389 * not yet updated second array are still using the old steeper slope.
398 * |12345678---> reader order
404 * So reader 6 will observe time going backwards versus reader 5.
406 * While other CPUs are likely to be able observe that, the only way
407 * for a CPU local observation is when an NMI hits in the middle of
408 * the update. Timestamps taken from that NMI context might be ahead
409 * of the following timestamps. Callers need to be aware of that and
412 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
414 struct tk_read_base *tkr;
419 seq = raw_read_seqcount_latch(&tkf->seq);
420 tkr = tkf->base + (seq & 0x01);
421 now = ktime_to_ns(tkr->base);
423 now += timekeeping_delta_to_ns(tkr,
428 } while (read_seqcount_retry(&tkf->seq, seq));
433 u64 ktime_get_mono_fast_ns(void)
435 return __ktime_get_fast_ns(&tk_fast_mono);
437 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
439 u64 ktime_get_raw_fast_ns(void)
441 return __ktime_get_fast_ns(&tk_fast_raw);
443 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
446 * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
448 * To keep it NMI safe since we're accessing from tracing, we're not using a
449 * separate timekeeper with updates to monotonic clock and boot offset
450 * protected with seqlocks. This has the following minor side effects:
452 * (1) Its possible that a timestamp be taken after the boot offset is updated
453 * but before the timekeeper is updated. If this happens, the new boot offset
454 * is added to the old timekeeping making the clock appear to update slightly
457 * timekeeping_inject_sleeptime64()
458 * __timekeeping_inject_sleeptime(tk, delta);
460 * timekeeping_update(tk, TK_CLEAR_NTP...);
462 * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
463 * partially updated. Since the tk->offs_boot update is a rare event, this
464 * should be a rare occurrence which postprocessing should be able to handle.
466 u64 notrace ktime_get_boot_fast_ns(void)
468 struct timekeeper *tk = &tk_core.timekeeper;
470 return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
472 EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
474 /* Suspend-time cycles value for halted fast timekeeper. */
475 static u64 cycles_at_suspend;
477 static u64 dummy_clock_read(struct clocksource *cs)
479 return cycles_at_suspend;
482 static struct clocksource dummy_clock = {
483 .read = dummy_clock_read,
487 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
488 * @tk: Timekeeper to snapshot.
490 * It generally is unsafe to access the clocksource after timekeeping has been
491 * suspended, so take a snapshot of the readout base of @tk and use it as the
492 * fast timekeeper's readout base while suspended. It will return the same
493 * number of cycles every time until timekeeping is resumed at which time the
494 * proper readout base for the fast timekeeper will be restored automatically.
496 static void halt_fast_timekeeper(struct timekeeper *tk)
498 static struct tk_read_base tkr_dummy;
499 struct tk_read_base *tkr = &tk->tkr_mono;
501 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
502 cycles_at_suspend = tk_clock_read(tkr);
503 tkr_dummy.clock = &dummy_clock;
504 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
507 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
508 tkr_dummy.clock = &dummy_clock;
509 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
512 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
514 static inline void update_vsyscall(struct timekeeper *tk)
516 struct timespec xt, wm;
518 xt = timespec64_to_timespec(tk_xtime(tk));
519 wm = timespec64_to_timespec(tk->wall_to_monotonic);
520 update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult,
521 tk->tkr_mono.cycle_last);
524 static inline void old_vsyscall_fixup(struct timekeeper *tk)
529 * Store only full nanoseconds into xtime_nsec after rounding
530 * it up and add the remainder to the error difference.
531 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
532 * by truncating the remainder in vsyscalls. However, it causes
533 * additional work to be done in timekeeping_adjust(). Once
534 * the vsyscall implementations are converted to use xtime_nsec
535 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
536 * users are removed, this can be killed.
538 remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1);
539 if (remainder != 0) {
540 tk->tkr_mono.xtime_nsec -= remainder;
541 tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift;
542 tk->ntp_error += remainder << tk->ntp_error_shift;
543 tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift;
547 #define old_vsyscall_fixup(tk)
550 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
552 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
554 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
558 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
560 int pvclock_gtod_register_notifier(struct notifier_block *nb)
562 struct timekeeper *tk = &tk_core.timekeeper;
566 raw_spin_lock_irqsave(&timekeeper_lock, flags);
567 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
568 update_pvclock_gtod(tk, true);
569 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
573 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
576 * pvclock_gtod_unregister_notifier - unregister a pvclock
577 * timedata update listener
579 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
584 raw_spin_lock_irqsave(&timekeeper_lock, flags);
585 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
586 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
590 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
593 * tk_update_leap_state - helper to update the next_leap_ktime
595 static inline void tk_update_leap_state(struct timekeeper *tk)
597 tk->next_leap_ktime = ntp_get_next_leap();
598 if (tk->next_leap_ktime != KTIME_MAX)
599 /* Convert to monotonic time */
600 tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
604 * Update the ktime_t based scalar nsec members of the timekeeper
606 static inline void tk_update_ktime_data(struct timekeeper *tk)
612 * The xtime based monotonic readout is:
613 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
614 * The ktime based monotonic readout is:
615 * nsec = base_mono + now();
616 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
618 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
619 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
620 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
622 /* Update the monotonic raw base */
623 tk->tkr_raw.base = timespec64_to_ktime(tk->raw_time);
626 * The sum of the nanoseconds portions of xtime and
627 * wall_to_monotonic can be greater/equal one second. Take
628 * this into account before updating tk->ktime_sec.
630 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
631 if (nsec >= NSEC_PER_SEC)
633 tk->ktime_sec = seconds;
636 /* must hold timekeeper_lock */
637 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
639 if (action & TK_CLEAR_NTP) {
644 tk_update_leap_state(tk);
645 tk_update_ktime_data(tk);
648 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
650 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
651 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
653 if (action & TK_CLOCK_WAS_SET)
654 tk->clock_was_set_seq++;
656 * The mirroring of the data to the shadow-timekeeper needs
657 * to happen last here to ensure we don't over-write the
658 * timekeeper structure on the next update with stale data
660 if (action & TK_MIRROR)
661 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
662 sizeof(tk_core.timekeeper));
666 * timekeeping_forward_now - update clock to the current time
668 * Forward the current clock to update its state since the last call to
669 * update_wall_time(). This is useful before significant clock changes,
670 * as it avoids having to deal with this time offset explicitly.
672 static void timekeeping_forward_now(struct timekeeper *tk)
674 u64 cycle_now, delta;
677 cycle_now = tk_clock_read(&tk->tkr_mono);
678 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
679 tk->tkr_mono.cycle_last = cycle_now;
680 tk->tkr_raw.cycle_last = cycle_now;
682 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
684 /* If arch requires, add in get_arch_timeoffset() */
685 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
687 tk_normalize_xtime(tk);
689 nsec = clocksource_cyc2ns(delta, tk->tkr_raw.mult, tk->tkr_raw.shift);
690 timespec64_add_ns(&tk->raw_time, nsec);
694 * __getnstimeofday64 - Returns the time of day in a timespec64.
695 * @ts: pointer to the timespec to be set
697 * Updates the time of day in the timespec.
698 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
700 int __getnstimeofday64(struct timespec64 *ts)
702 struct timekeeper *tk = &tk_core.timekeeper;
707 seq = read_seqcount_begin(&tk_core.seq);
709 ts->tv_sec = tk->xtime_sec;
710 nsecs = timekeeping_get_ns(&tk->tkr_mono);
712 } while (read_seqcount_retry(&tk_core.seq, seq));
715 timespec64_add_ns(ts, nsecs);
718 * Do not bail out early, in case there were callers still using
719 * the value, even in the face of the WARN_ON.
721 if (unlikely(timekeeping_suspended))
725 EXPORT_SYMBOL(__getnstimeofday64);
728 * getnstimeofday64 - Returns the time of day in a timespec64.
729 * @ts: pointer to the timespec64 to be set
731 * Returns the time of day in a timespec64 (WARN if suspended).
733 void getnstimeofday64(struct timespec64 *ts)
735 WARN_ON(__getnstimeofday64(ts));
737 EXPORT_SYMBOL(getnstimeofday64);
739 ktime_t ktime_get(void)
741 struct timekeeper *tk = &tk_core.timekeeper;
746 WARN_ON(timekeeping_suspended);
749 seq = read_seqcount_begin(&tk_core.seq);
750 base = tk->tkr_mono.base;
751 nsecs = timekeeping_get_ns(&tk->tkr_mono);
753 } while (read_seqcount_retry(&tk_core.seq, seq));
755 return ktime_add_ns(base, nsecs);
757 EXPORT_SYMBOL_GPL(ktime_get);
759 u32 ktime_get_resolution_ns(void)
761 struct timekeeper *tk = &tk_core.timekeeper;
765 WARN_ON(timekeeping_suspended);
768 seq = read_seqcount_begin(&tk_core.seq);
769 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
770 } while (read_seqcount_retry(&tk_core.seq, seq));
774 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
776 static ktime_t *offsets[TK_OFFS_MAX] = {
777 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
778 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
779 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
782 ktime_t ktime_get_with_offset(enum tk_offsets offs)
784 struct timekeeper *tk = &tk_core.timekeeper;
786 ktime_t base, *offset = offsets[offs];
789 WARN_ON(timekeeping_suspended);
792 seq = read_seqcount_begin(&tk_core.seq);
793 base = ktime_add(tk->tkr_mono.base, *offset);
794 nsecs = timekeeping_get_ns(&tk->tkr_mono);
796 } while (read_seqcount_retry(&tk_core.seq, seq));
798 return ktime_add_ns(base, nsecs);
801 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
804 * ktime_mono_to_any() - convert mononotic time to any other time
805 * @tmono: time to convert.
806 * @offs: which offset to use
808 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
810 ktime_t *offset = offsets[offs];
815 seq = read_seqcount_begin(&tk_core.seq);
816 tconv = ktime_add(tmono, *offset);
817 } while (read_seqcount_retry(&tk_core.seq, seq));
821 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
824 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
826 ktime_t ktime_get_raw(void)
828 struct timekeeper *tk = &tk_core.timekeeper;
834 seq = read_seqcount_begin(&tk_core.seq);
835 base = tk->tkr_raw.base;
836 nsecs = timekeeping_get_ns(&tk->tkr_raw);
838 } while (read_seqcount_retry(&tk_core.seq, seq));
840 return ktime_add_ns(base, nsecs);
842 EXPORT_SYMBOL_GPL(ktime_get_raw);
845 * ktime_get_ts64 - get the monotonic clock in timespec64 format
846 * @ts: pointer to timespec variable
848 * The function calculates the monotonic clock from the realtime
849 * clock and the wall_to_monotonic offset and stores the result
850 * in normalized timespec64 format in the variable pointed to by @ts.
852 void ktime_get_ts64(struct timespec64 *ts)
854 struct timekeeper *tk = &tk_core.timekeeper;
855 struct timespec64 tomono;
859 WARN_ON(timekeeping_suspended);
862 seq = read_seqcount_begin(&tk_core.seq);
863 ts->tv_sec = tk->xtime_sec;
864 nsec = timekeeping_get_ns(&tk->tkr_mono);
865 tomono = tk->wall_to_monotonic;
867 } while (read_seqcount_retry(&tk_core.seq, seq));
869 ts->tv_sec += tomono.tv_sec;
871 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
873 EXPORT_SYMBOL_GPL(ktime_get_ts64);
876 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
878 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
879 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
880 * works on both 32 and 64 bit systems. On 32 bit systems the readout
881 * covers ~136 years of uptime which should be enough to prevent
882 * premature wrap arounds.
884 time64_t ktime_get_seconds(void)
886 struct timekeeper *tk = &tk_core.timekeeper;
888 WARN_ON(timekeeping_suspended);
889 return tk->ktime_sec;
891 EXPORT_SYMBOL_GPL(ktime_get_seconds);
894 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
896 * Returns the wall clock seconds since 1970. This replaces the
897 * get_seconds() interface which is not y2038 safe on 32bit systems.
899 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
900 * 32bit systems the access must be protected with the sequence
901 * counter to provide "atomic" access to the 64bit tk->xtime_sec
904 time64_t ktime_get_real_seconds(void)
906 struct timekeeper *tk = &tk_core.timekeeper;
910 if (IS_ENABLED(CONFIG_64BIT))
911 return tk->xtime_sec;
914 seq = read_seqcount_begin(&tk_core.seq);
915 seconds = tk->xtime_sec;
917 } while (read_seqcount_retry(&tk_core.seq, seq));
921 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
924 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
925 * but without the sequence counter protect. This internal function
926 * is called just when timekeeping lock is already held.
928 time64_t __ktime_get_real_seconds(void)
930 struct timekeeper *tk = &tk_core.timekeeper;
932 return tk->xtime_sec;
936 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
937 * @systime_snapshot: pointer to struct receiving the system time snapshot
939 void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
941 struct timekeeper *tk = &tk_core.timekeeper;
949 WARN_ON_ONCE(timekeeping_suspended);
952 seq = read_seqcount_begin(&tk_core.seq);
953 now = tk_clock_read(&tk->tkr_mono);
954 systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
955 systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
956 base_real = ktime_add(tk->tkr_mono.base,
957 tk_core.timekeeper.offs_real);
958 base_raw = tk->tkr_raw.base;
959 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
960 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
961 } while (read_seqcount_retry(&tk_core.seq, seq));
963 systime_snapshot->cycles = now;
964 systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
965 systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
967 EXPORT_SYMBOL_GPL(ktime_get_snapshot);
969 /* Scale base by mult/div checking for overflow */
970 static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
974 tmp = div64_u64_rem(*base, div, &rem);
976 if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
977 ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
988 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
989 * @history: Snapshot representing start of history
990 * @partial_history_cycles: Cycle offset into history (fractional part)
991 * @total_history_cycles: Total history length in cycles
992 * @discontinuity: True indicates clock was set on history period
993 * @ts: Cross timestamp that should be adjusted using
994 * partial/total ratio
996 * Helper function used by get_device_system_crosststamp() to correct the
997 * crosstimestamp corresponding to the start of the current interval to the
998 * system counter value (timestamp point) provided by the driver. The
999 * total_history_* quantities are the total history starting at the provided
1000 * reference point and ending at the start of the current interval. The cycle
1001 * count between the driver timestamp point and the start of the current
1002 * interval is partial_history_cycles.
1004 static int adjust_historical_crosststamp(struct system_time_snapshot *history,
1005 u64 partial_history_cycles,
1006 u64 total_history_cycles,
1008 struct system_device_crosststamp *ts)
1010 struct timekeeper *tk = &tk_core.timekeeper;
1011 u64 corr_raw, corr_real;
1012 bool interp_forward;
1015 if (total_history_cycles == 0 || partial_history_cycles == 0)
1018 /* Interpolate shortest distance from beginning or end of history */
1019 interp_forward = partial_history_cycles > total_history_cycles / 2;
1020 partial_history_cycles = interp_forward ?
1021 total_history_cycles - partial_history_cycles :
1022 partial_history_cycles;
1025 * Scale the monotonic raw time delta by:
1026 * partial_history_cycles / total_history_cycles
1028 corr_raw = (u64)ktime_to_ns(
1029 ktime_sub(ts->sys_monoraw, history->raw));
1030 ret = scale64_check_overflow(partial_history_cycles,
1031 total_history_cycles, &corr_raw);
1036 * If there is a discontinuity in the history, scale monotonic raw
1038 * mult(real)/mult(raw) yielding the realtime correction
1039 * Otherwise, calculate the realtime correction similar to monotonic
1042 if (discontinuity) {
1043 corr_real = mul_u64_u32_div
1044 (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1046 corr_real = (u64)ktime_to_ns(
1047 ktime_sub(ts->sys_realtime, history->real));
1048 ret = scale64_check_overflow(partial_history_cycles,
1049 total_history_cycles, &corr_real);
1054 /* Fixup monotonic raw and real time time values */
1055 if (interp_forward) {
1056 ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1057 ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1059 ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1060 ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1067 * cycle_between - true if test occurs chronologically between before and after
1069 static bool cycle_between(u64 before, u64 test, u64 after)
1071 if (test > before && test < after)
1073 if (test < before && before > after)
1079 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1080 * @get_time_fn: Callback to get simultaneous device time and
1081 * system counter from the device driver
1082 * @ctx: Context passed to get_time_fn()
1083 * @history_begin: Historical reference point used to interpolate system
1084 * time when counter provided by the driver is before the current interval
1085 * @xtstamp: Receives simultaneously captured system and device time
1087 * Reads a timestamp from a device and correlates it to system time
1089 int get_device_system_crosststamp(int (*get_time_fn)
1090 (ktime_t *device_time,
1091 struct system_counterval_t *sys_counterval,
1094 struct system_time_snapshot *history_begin,
1095 struct system_device_crosststamp *xtstamp)
1097 struct system_counterval_t system_counterval;
1098 struct timekeeper *tk = &tk_core.timekeeper;
1099 u64 cycles, now, interval_start;
1100 unsigned int clock_was_set_seq = 0;
1101 ktime_t base_real, base_raw;
1102 u64 nsec_real, nsec_raw;
1103 u8 cs_was_changed_seq;
1109 seq = read_seqcount_begin(&tk_core.seq);
1111 * Try to synchronously capture device time and a system
1112 * counter value calling back into the device driver
1114 ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1119 * Verify that the clocksource associated with the captured
1120 * system counter value is the same as the currently installed
1121 * timekeeper clocksource
1123 if (tk->tkr_mono.clock != system_counterval.cs)
1125 cycles = system_counterval.cycles;
1128 * Check whether the system counter value provided by the
1129 * device driver is on the current timekeeping interval.
1131 now = tk_clock_read(&tk->tkr_mono);
1132 interval_start = tk->tkr_mono.cycle_last;
1133 if (!cycle_between(interval_start, cycles, now)) {
1134 clock_was_set_seq = tk->clock_was_set_seq;
1135 cs_was_changed_seq = tk->cs_was_changed_seq;
1136 cycles = interval_start;
1142 base_real = ktime_add(tk->tkr_mono.base,
1143 tk_core.timekeeper.offs_real);
1144 base_raw = tk->tkr_raw.base;
1146 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1147 system_counterval.cycles);
1148 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1149 system_counterval.cycles);
1150 } while (read_seqcount_retry(&tk_core.seq, seq));
1152 xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1153 xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1156 * Interpolate if necessary, adjusting back from the start of the
1160 u64 partial_history_cycles, total_history_cycles;
1164 * Check that the counter value occurs after the provided
1165 * history reference and that the history doesn't cross a
1166 * clocksource change
1168 if (!history_begin ||
1169 !cycle_between(history_begin->cycles,
1170 system_counterval.cycles, cycles) ||
1171 history_begin->cs_was_changed_seq != cs_was_changed_seq)
1173 partial_history_cycles = cycles - system_counterval.cycles;
1174 total_history_cycles = cycles - history_begin->cycles;
1176 history_begin->clock_was_set_seq != clock_was_set_seq;
1178 ret = adjust_historical_crosststamp(history_begin,
1179 partial_history_cycles,
1180 total_history_cycles,
1181 discontinuity, xtstamp);
1188 EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1191 * do_gettimeofday - Returns the time of day in a timeval
1192 * @tv: pointer to the timeval to be set
1194 * NOTE: Users should be converted to using getnstimeofday()
1196 void do_gettimeofday(struct timeval *tv)
1198 struct timespec64 now;
1200 getnstimeofday64(&now);
1201 tv->tv_sec = now.tv_sec;
1202 tv->tv_usec = now.tv_nsec/1000;
1204 EXPORT_SYMBOL(do_gettimeofday);
1207 * do_settimeofday64 - Sets the time of day.
1208 * @ts: pointer to the timespec64 variable containing the new time
1210 * Sets the time of day to the new time and update NTP and notify hrtimers
1212 int do_settimeofday64(const struct timespec64 *ts)
1214 struct timekeeper *tk = &tk_core.timekeeper;
1215 struct timespec64 ts_delta, xt;
1216 unsigned long flags;
1219 if (!timespec64_valid_strict(ts))
1222 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1223 write_seqcount_begin(&tk_core.seq);
1225 timekeeping_forward_now(tk);
1228 ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
1229 ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
1231 if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1236 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1238 tk_set_xtime(tk, ts);
1240 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1242 write_seqcount_end(&tk_core.seq);
1243 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1245 /* signal hrtimers about time change */
1250 EXPORT_SYMBOL(do_settimeofday64);
1253 * timekeeping_inject_offset - Adds or subtracts from the current time.
1254 * @tv: pointer to the timespec variable containing the offset
1256 * Adds or subtracts an offset value from the current time.
1258 int timekeeping_inject_offset(struct timespec *ts)
1260 struct timekeeper *tk = &tk_core.timekeeper;
1261 unsigned long flags;
1262 struct timespec64 ts64, tmp;
1265 if (!timespec_inject_offset_valid(ts))
1268 ts64 = timespec_to_timespec64(*ts);
1270 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1271 write_seqcount_begin(&tk_core.seq);
1273 timekeeping_forward_now(tk);
1275 /* Make sure the proposed value is valid */
1276 tmp = timespec64_add(tk_xtime(tk), ts64);
1277 if (timespec64_compare(&tk->wall_to_monotonic, &ts64) > 0 ||
1278 !timespec64_valid_strict(&tmp)) {
1283 tk_xtime_add(tk, &ts64);
1284 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
1286 error: /* even if we error out, we forwarded the time, so call update */
1287 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1289 write_seqcount_end(&tk_core.seq);
1290 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1292 /* signal hrtimers about time change */
1297 EXPORT_SYMBOL(timekeeping_inject_offset);
1300 * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
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 * change_clocksource - Swaps clocksources if a new one is available
1312 * Accumulates current time interval and initializes new clocksource
1314 static int change_clocksource(void *data)
1316 struct timekeeper *tk = &tk_core.timekeeper;
1317 struct clocksource *new, *old;
1318 unsigned long flags;
1320 new = (struct clocksource *) data;
1322 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1323 write_seqcount_begin(&tk_core.seq);
1325 timekeeping_forward_now(tk);
1327 * If the cs is in module, get a module reference. Succeeds
1328 * for built-in code (owner == NULL) as well.
1330 if (try_module_get(new->owner)) {
1331 if (!new->enable || new->enable(new) == 0) {
1332 old = tk->tkr_mono.clock;
1333 tk_setup_internals(tk, new);
1336 module_put(old->owner);
1338 module_put(new->owner);
1341 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1343 write_seqcount_end(&tk_core.seq);
1344 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1350 * timekeeping_notify - Install a new clock source
1351 * @clock: pointer to the clock source
1353 * This function is called from clocksource.c after a new, better clock
1354 * source has been registered. The caller holds the clocksource_mutex.
1356 int timekeeping_notify(struct clocksource *clock)
1358 struct timekeeper *tk = &tk_core.timekeeper;
1360 if (tk->tkr_mono.clock == clock)
1362 stop_machine(change_clocksource, clock, NULL);
1363 tick_clock_notify();
1364 return tk->tkr_mono.clock == clock ? 0 : -1;
1368 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1369 * @ts: pointer to the timespec64 to be set
1371 * Returns the raw monotonic time (completely un-modified by ntp)
1373 void getrawmonotonic64(struct timespec64 *ts)
1375 struct timekeeper *tk = &tk_core.timekeeper;
1376 struct timespec64 ts64;
1381 seq = read_seqcount_begin(&tk_core.seq);
1382 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1383 ts64 = tk->raw_time;
1385 } while (read_seqcount_retry(&tk_core.seq, seq));
1387 timespec64_add_ns(&ts64, nsecs);
1390 EXPORT_SYMBOL(getrawmonotonic64);
1394 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1396 int timekeeping_valid_for_hres(void)
1398 struct timekeeper *tk = &tk_core.timekeeper;
1403 seq = read_seqcount_begin(&tk_core.seq);
1405 ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1407 } while (read_seqcount_retry(&tk_core.seq, seq));
1413 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1415 u64 timekeeping_max_deferment(void)
1417 struct timekeeper *tk = &tk_core.timekeeper;
1422 seq = read_seqcount_begin(&tk_core.seq);
1424 ret = tk->tkr_mono.clock->max_idle_ns;
1426 } while (read_seqcount_retry(&tk_core.seq, seq));
1432 * read_persistent_clock - Return time from the persistent clock.
1434 * Weak dummy function for arches that do not yet support it.
1435 * Reads the time from the battery backed persistent clock.
1436 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1438 * XXX - Do be sure to remove it once all arches implement it.
1440 void __weak read_persistent_clock(struct timespec *ts)
1446 void __weak read_persistent_clock64(struct timespec64 *ts64)
1450 read_persistent_clock(&ts);
1451 *ts64 = timespec_to_timespec64(ts);
1455 * read_boot_clock64 - Return time of the system start.
1457 * Weak dummy function for arches that do not yet support it.
1458 * Function to read the exact time the system has been started.
1459 * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported.
1461 * XXX - Do be sure to remove it once all arches implement it.
1463 void __weak read_boot_clock64(struct timespec64 *ts)
1469 /* Flag for if timekeeping_resume() has injected sleeptime */
1470 static bool sleeptime_injected;
1472 /* Flag for if there is a persistent clock on this platform */
1473 static bool persistent_clock_exists;
1476 * timekeeping_init - Initializes the clocksource and common timekeeping values
1478 void __init timekeeping_init(void)
1480 struct timekeeper *tk = &tk_core.timekeeper;
1481 struct clocksource *clock;
1482 unsigned long flags;
1483 struct timespec64 now, boot, tmp;
1485 read_persistent_clock64(&now);
1486 if (!timespec64_valid_strict(&now)) {
1487 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1488 " Check your CMOS/BIOS settings.\n");
1491 } else if (now.tv_sec || now.tv_nsec)
1492 persistent_clock_exists = true;
1494 read_boot_clock64(&boot);
1495 if (!timespec64_valid_strict(&boot)) {
1496 pr_warn("WARNING: Boot clock returned invalid value!\n"
1497 " Check your CMOS/BIOS settings.\n");
1502 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1503 write_seqcount_begin(&tk_core.seq);
1506 clock = clocksource_default_clock();
1508 clock->enable(clock);
1509 tk_setup_internals(tk, clock);
1511 tk_set_xtime(tk, &now);
1512 tk->raw_time.tv_sec = 0;
1513 tk->raw_time.tv_nsec = 0;
1514 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1515 boot = tk_xtime(tk);
1517 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1518 tk_set_wall_to_mono(tk, tmp);
1520 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1522 write_seqcount_end(&tk_core.seq);
1523 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1526 /* time in seconds when suspend began for persistent clock */
1527 static struct timespec64 timekeeping_suspend_time;
1530 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1531 * @delta: pointer to a timespec delta value
1533 * Takes a timespec offset measuring a suspend interval and properly
1534 * adds the sleep offset to the timekeeping variables.
1536 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1537 struct timespec64 *delta)
1539 if (!timespec64_valid_strict(delta)) {
1540 printk_deferred(KERN_WARNING
1541 "__timekeeping_inject_sleeptime: Invalid "
1542 "sleep delta value!\n");
1545 tk_xtime_add(tk, delta);
1546 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1547 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1548 tk_debug_account_sleep_time(delta);
1551 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1553 * We have three kinds of time sources to use for sleep time
1554 * injection, the preference order is:
1555 * 1) non-stop clocksource
1556 * 2) persistent clock (ie: RTC accessible when irqs are off)
1559 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1560 * If system has neither 1) nor 2), 3) will be used finally.
1563 * If timekeeping has injected sleeptime via either 1) or 2),
1564 * 3) becomes needless, so in this case we don't need to call
1565 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1568 bool timekeeping_rtc_skipresume(void)
1570 return sleeptime_injected;
1574 * 1) can be determined whether to use or not only when doing
1575 * timekeeping_resume() which is invoked after rtc_suspend(),
1576 * so we can't skip rtc_suspend() surely if system has 1).
1578 * But if system has 2), 2) will definitely be used, so in this
1579 * case we don't need to call rtc_suspend(), and this is what
1580 * timekeeping_rtc_skipsuspend() means.
1582 bool timekeeping_rtc_skipsuspend(void)
1584 return persistent_clock_exists;
1588 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1589 * @delta: pointer to a timespec64 delta value
1591 * This hook is for architectures that cannot support read_persistent_clock64
1592 * because their RTC/persistent clock is only accessible when irqs are enabled.
1593 * and also don't have an effective nonstop clocksource.
1595 * This function should only be called by rtc_resume(), and allows
1596 * a suspend offset to be injected into the timekeeping values.
1598 void timekeeping_inject_sleeptime64(struct timespec64 *delta)
1600 struct timekeeper *tk = &tk_core.timekeeper;
1601 unsigned long flags;
1603 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1604 write_seqcount_begin(&tk_core.seq);
1606 timekeeping_forward_now(tk);
1608 __timekeeping_inject_sleeptime(tk, delta);
1610 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1612 write_seqcount_end(&tk_core.seq);
1613 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1615 /* signal hrtimers about time change */
1621 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1623 void timekeeping_resume(void)
1625 struct timekeeper *tk = &tk_core.timekeeper;
1626 struct clocksource *clock = tk->tkr_mono.clock;
1627 unsigned long flags;
1628 struct timespec64 ts_new, ts_delta;
1631 sleeptime_injected = false;
1632 read_persistent_clock64(&ts_new);
1634 clockevents_resume();
1635 clocksource_resume();
1637 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1638 write_seqcount_begin(&tk_core.seq);
1641 * After system resumes, we need to calculate the suspended time and
1642 * compensate it for the OS time. There are 3 sources that could be
1643 * used: Nonstop clocksource during suspend, persistent clock and rtc
1646 * One specific platform may have 1 or 2 or all of them, and the
1647 * preference will be:
1648 * suspend-nonstop clocksource -> persistent clock -> rtc
1649 * The less preferred source will only be tried if there is no better
1650 * usable source. The rtc part is handled separately in rtc core code.
1652 cycle_now = tk_clock_read(&tk->tkr_mono);
1653 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1654 cycle_now > tk->tkr_mono.cycle_last) {
1655 u64 nsec, cyc_delta;
1657 cyc_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
1659 nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift);
1660 ts_delta = ns_to_timespec64(nsec);
1661 sleeptime_injected = true;
1662 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1663 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1664 sleeptime_injected = true;
1667 if (sleeptime_injected)
1668 __timekeeping_inject_sleeptime(tk, &ts_delta);
1670 /* Re-base the last cycle value */
1671 tk->tkr_mono.cycle_last = cycle_now;
1672 tk->tkr_raw.cycle_last = cycle_now;
1675 timekeeping_suspended = 0;
1676 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1677 write_seqcount_end(&tk_core.seq);
1678 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1680 touch_softlockup_watchdog();
1686 int timekeeping_suspend(void)
1688 struct timekeeper *tk = &tk_core.timekeeper;
1689 unsigned long flags;
1690 struct timespec64 delta, delta_delta;
1691 static struct timespec64 old_delta;
1693 read_persistent_clock64(&timekeeping_suspend_time);
1696 * On some systems the persistent_clock can not be detected at
1697 * timekeeping_init by its return value, so if we see a valid
1698 * value returned, update the persistent_clock_exists flag.
1700 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1701 persistent_clock_exists = true;
1703 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1704 write_seqcount_begin(&tk_core.seq);
1705 timekeeping_forward_now(tk);
1706 timekeeping_suspended = 1;
1708 if (persistent_clock_exists) {
1710 * To avoid drift caused by repeated suspend/resumes,
1711 * which each can add ~1 second drift error,
1712 * try to compensate so the difference in system time
1713 * and persistent_clock time stays close to constant.
1715 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1716 delta_delta = timespec64_sub(delta, old_delta);
1717 if (abs(delta_delta.tv_sec) >= 2) {
1719 * if delta_delta is too large, assume time correction
1720 * has occurred and set old_delta to the current delta.
1724 /* Otherwise try to adjust old_system to compensate */
1725 timekeeping_suspend_time =
1726 timespec64_add(timekeeping_suspend_time, delta_delta);
1730 timekeeping_update(tk, TK_MIRROR);
1731 halt_fast_timekeeper(tk);
1732 write_seqcount_end(&tk_core.seq);
1733 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1736 clocksource_suspend();
1737 clockevents_suspend();
1742 /* sysfs resume/suspend bits for timekeeping */
1743 static struct syscore_ops timekeeping_syscore_ops = {
1744 .resume = timekeeping_resume,
1745 .suspend = timekeeping_suspend,
1748 static int __init timekeeping_init_ops(void)
1750 register_syscore_ops(&timekeeping_syscore_ops);
1753 device_initcall(timekeeping_init_ops);
1756 * Apply a multiplier adjustment to the timekeeper
1758 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1763 s64 interval = tk->cycle_interval;
1767 mult_adj = -mult_adj;
1768 interval = -interval;
1771 mult_adj <<= adj_scale;
1772 interval <<= adj_scale;
1773 offset <<= adj_scale;
1776 * So the following can be confusing.
1778 * To keep things simple, lets assume mult_adj == 1 for now.
1780 * When mult_adj != 1, remember that the interval and offset values
1781 * have been appropriately scaled so the math is the same.
1783 * The basic idea here is that we're increasing the multiplier
1784 * by one, this causes the xtime_interval to be incremented by
1785 * one cycle_interval. This is because:
1786 * xtime_interval = cycle_interval * mult
1787 * So if mult is being incremented by one:
1788 * xtime_interval = cycle_interval * (mult + 1)
1790 * xtime_interval = (cycle_interval * mult) + cycle_interval
1791 * Which can be shortened to:
1792 * xtime_interval += cycle_interval
1794 * So offset stores the non-accumulated cycles. Thus the current
1795 * time (in shifted nanoseconds) is:
1796 * now = (offset * adj) + xtime_nsec
1797 * Now, even though we're adjusting the clock frequency, we have
1798 * to keep time consistent. In other words, we can't jump back
1799 * in time, and we also want to avoid jumping forward in time.
1801 * So given the same offset value, we need the time to be the same
1802 * both before and after the freq adjustment.
1803 * now = (offset * adj_1) + xtime_nsec_1
1804 * now = (offset * adj_2) + xtime_nsec_2
1806 * (offset * adj_1) + xtime_nsec_1 =
1807 * (offset * adj_2) + xtime_nsec_2
1811 * (offset * adj_1) + xtime_nsec_1 =
1812 * (offset * (adj_1+1)) + xtime_nsec_2
1813 * (offset * adj_1) + xtime_nsec_1 =
1814 * (offset * adj_1) + offset + xtime_nsec_2
1815 * Canceling the sides:
1816 * xtime_nsec_1 = offset + xtime_nsec_2
1818 * xtime_nsec_2 = xtime_nsec_1 - offset
1819 * Which simplfies to:
1820 * xtime_nsec -= offset
1822 * XXX - TODO: Doc ntp_error calculation.
1824 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1825 /* NTP adjustment caused clocksource mult overflow */
1830 tk->tkr_mono.mult += mult_adj;
1831 tk->xtime_interval += interval;
1832 tk->tkr_mono.xtime_nsec -= offset;
1833 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1837 * Calculate the multiplier adjustment needed to match the frequency
1840 static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
1843 s64 interval = tk->cycle_interval;
1844 s64 xinterval = tk->xtime_interval;
1845 u32 base = tk->tkr_mono.clock->mult;
1846 u32 max = tk->tkr_mono.clock->maxadj;
1847 u32 cur_adj = tk->tkr_mono.mult;
1852 /* Remove any current error adj from freq calculation */
1853 if (tk->ntp_err_mult)
1854 xinterval -= tk->cycle_interval;
1856 tk->ntp_tick = ntp_tick_length();
1858 /* Calculate current error per tick */
1859 tick_error = ntp_tick_length() >> tk->ntp_error_shift;
1860 tick_error -= (xinterval + tk->xtime_remainder);
1862 /* Don't worry about correcting it if its small */
1863 if (likely((tick_error >= 0) && (tick_error <= interval)))
1866 /* preserve the direction of correction */
1867 negative = (tick_error < 0);
1869 /* If any adjustment would pass the max, just return */
1870 if (negative && (cur_adj - 1) <= (base - max))
1872 if (!negative && (cur_adj + 1) >= (base + max))
1875 * Sort out the magnitude of the correction, but
1876 * avoid making so large a correction that we go
1877 * over the max adjustment.
1880 tick_error = abs(tick_error);
1881 while (tick_error > interval) {
1882 u32 adj = 1 << (adj_scale + 1);
1884 /* Check if adjustment gets us within 1 unit from the max */
1885 if (negative && (cur_adj - adj) <= (base - max))
1887 if (!negative && (cur_adj + adj) >= (base + max))
1894 /* scale the corrections */
1895 timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
1899 * Adjust the timekeeper's multiplier to the correct frequency
1900 * and also to reduce the accumulated error value.
1902 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1904 /* Correct for the current frequency error */
1905 timekeeping_freqadjust(tk, offset);
1907 /* Next make a small adjustment to fix any cumulative error */
1908 if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
1909 tk->ntp_err_mult = 1;
1910 timekeeping_apply_adjustment(tk, offset, 0, 0);
1911 } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
1912 /* Undo any existing error adjustment */
1913 timekeeping_apply_adjustment(tk, offset, 1, 0);
1914 tk->ntp_err_mult = 0;
1917 if (unlikely(tk->tkr_mono.clock->maxadj &&
1918 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1919 > tk->tkr_mono.clock->maxadj))) {
1920 printk_once(KERN_WARNING
1921 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1922 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1923 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1927 * It may be possible that when we entered this function, xtime_nsec
1928 * was very small. Further, if we're slightly speeding the clocksource
1929 * in the code above, its possible the required corrective factor to
1930 * xtime_nsec could cause it to underflow.
1932 * Now, since we already accumulated the second, cannot simply roll
1933 * the accumulated second back, since the NTP subsystem has been
1934 * notified via second_overflow. So instead we push xtime_nsec forward
1935 * by the amount we underflowed, and add that amount into the error.
1937 * We'll correct this error next time through this function, when
1938 * xtime_nsec is not as small.
1940 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1941 s64 neg = -(s64)tk->tkr_mono.xtime_nsec;
1942 tk->tkr_mono.xtime_nsec = 0;
1943 tk->ntp_error += neg << tk->ntp_error_shift;
1948 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1950 * Helper function that accumulates the nsecs greater than a second
1951 * from the xtime_nsec field to the xtime_secs field.
1952 * It also calls into the NTP code to handle leapsecond processing.
1955 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1957 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1958 unsigned int clock_set = 0;
1960 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1963 tk->tkr_mono.xtime_nsec -= nsecps;
1966 /* Figure out if its a leap sec and apply if needed */
1967 leap = second_overflow(tk->xtime_sec);
1968 if (unlikely(leap)) {
1969 struct timespec64 ts;
1971 tk->xtime_sec += leap;
1975 tk_set_wall_to_mono(tk,
1976 timespec64_sub(tk->wall_to_monotonic, ts));
1978 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1980 clock_set = TK_CLOCK_WAS_SET;
1987 * logarithmic_accumulation - shifted accumulation of cycles
1989 * This functions accumulates a shifted interval of cycles into
1990 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1993 * Returns the unconsumed cycles.
1995 static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
1996 u32 shift, unsigned int *clock_set)
1998 u64 interval = tk->cycle_interval << shift;
2001 /* If the offset is smaller than a shifted interval, do nothing */
2002 if (offset < interval)
2005 /* Accumulate one shifted interval */
2007 tk->tkr_mono.cycle_last += interval;
2008 tk->tkr_raw.cycle_last += interval;
2010 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2011 *clock_set |= accumulate_nsecs_to_secs(tk);
2013 /* Accumulate raw time */
2014 tk->tkr_raw.xtime_nsec += (u64)tk->raw_time.tv_nsec << tk->tkr_raw.shift;
2015 tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2016 snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2017 while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2018 tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2019 tk->raw_time.tv_sec++;
2021 tk->raw_time.tv_nsec = tk->tkr_raw.xtime_nsec >> tk->tkr_raw.shift;
2022 tk->tkr_raw.xtime_nsec -= (u64)tk->raw_time.tv_nsec << tk->tkr_raw.shift;
2024 /* Accumulate error between NTP and clock interval */
2025 tk->ntp_error += tk->ntp_tick << shift;
2026 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2027 (tk->ntp_error_shift + shift);
2033 * update_wall_time - Uses the current clocksource to increment the wall time
2036 void update_wall_time(void)
2038 struct timekeeper *real_tk = &tk_core.timekeeper;
2039 struct timekeeper *tk = &shadow_timekeeper;
2041 int shift = 0, maxshift;
2042 unsigned int clock_set = 0;
2043 unsigned long flags;
2045 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2047 /* Make sure we're fully resumed: */
2048 if (unlikely(timekeeping_suspended))
2051 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2052 offset = real_tk->cycle_interval;
2054 offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2055 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2058 /* Check if there's really nothing to do */
2059 if (offset < real_tk->cycle_interval)
2062 /* Do some additional sanity checking */
2063 timekeeping_check_update(real_tk, offset);
2066 * With NO_HZ we may have to accumulate many cycle_intervals
2067 * (think "ticks") worth of time at once. To do this efficiently,
2068 * we calculate the largest doubling multiple of cycle_intervals
2069 * that is smaller than the offset. We then accumulate that
2070 * chunk in one go, and then try to consume the next smaller
2073 shift = ilog2(offset) - ilog2(tk->cycle_interval);
2074 shift = max(0, shift);
2075 /* Bound shift to one less than what overflows tick_length */
2076 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2077 shift = min(shift, maxshift);
2078 while (offset >= tk->cycle_interval) {
2079 offset = logarithmic_accumulation(tk, offset, shift,
2081 if (offset < tk->cycle_interval<<shift)
2085 /* correct the clock when NTP error is too big */
2086 timekeeping_adjust(tk, offset);
2089 * XXX This can be killed once everyone converts
2090 * to the new update_vsyscall.
2092 old_vsyscall_fixup(tk);
2095 * Finally, make sure that after the rounding
2096 * xtime_nsec isn't larger than NSEC_PER_SEC
2098 clock_set |= accumulate_nsecs_to_secs(tk);
2100 write_seqcount_begin(&tk_core.seq);
2102 * Update the real timekeeper.
2104 * We could avoid this memcpy by switching pointers, but that
2105 * requires changes to all other timekeeper usage sites as
2106 * well, i.e. move the timekeeper pointer getter into the
2107 * spinlocked/seqcount protected sections. And we trade this
2108 * memcpy under the tk_core.seq against one before we start
2111 timekeeping_update(tk, clock_set);
2112 memcpy(real_tk, tk, sizeof(*tk));
2113 /* The memcpy must come last. Do not put anything here! */
2114 write_seqcount_end(&tk_core.seq);
2116 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2118 /* Have to call _delayed version, since in irq context*/
2119 clock_was_set_delayed();
2123 * getboottime64 - Return the real time of system boot.
2124 * @ts: pointer to the timespec64 to be set
2126 * Returns the wall-time of boot in a timespec64.
2128 * This is based on the wall_to_monotonic offset and the total suspend
2129 * time. Calls to settimeofday will affect the value returned (which
2130 * basically means that however wrong your real time clock is at boot time,
2131 * you get the right time here).
2133 void getboottime64(struct timespec64 *ts)
2135 struct timekeeper *tk = &tk_core.timekeeper;
2136 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2138 *ts = ktime_to_timespec64(t);
2140 EXPORT_SYMBOL_GPL(getboottime64);
2142 unsigned long get_seconds(void)
2144 struct timekeeper *tk = &tk_core.timekeeper;
2146 return tk->xtime_sec;
2148 EXPORT_SYMBOL(get_seconds);
2150 struct timespec __current_kernel_time(void)
2152 struct timekeeper *tk = &tk_core.timekeeper;
2154 return timespec64_to_timespec(tk_xtime(tk));
2157 struct timespec64 current_kernel_time64(void)
2159 struct timekeeper *tk = &tk_core.timekeeper;
2160 struct timespec64 now;
2164 seq = read_seqcount_begin(&tk_core.seq);
2167 } while (read_seqcount_retry(&tk_core.seq, seq));
2171 EXPORT_SYMBOL(current_kernel_time64);
2173 struct timespec64 get_monotonic_coarse64(void)
2175 struct timekeeper *tk = &tk_core.timekeeper;
2176 struct timespec64 now, mono;
2180 seq = read_seqcount_begin(&tk_core.seq);
2183 mono = tk->wall_to_monotonic;
2184 } while (read_seqcount_retry(&tk_core.seq, seq));
2186 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
2187 now.tv_nsec + mono.tv_nsec);
2191 EXPORT_SYMBOL(get_monotonic_coarse64);
2194 * Must hold jiffies_lock
2196 void do_timer(unsigned long ticks)
2198 jiffies_64 += ticks;
2199 calc_global_load(ticks);
2203 * ktime_get_update_offsets_now - hrtimer helper
2204 * @cwsseq: pointer to check and store the clock was set sequence number
2205 * @offs_real: pointer to storage for monotonic -> realtime offset
2206 * @offs_boot: pointer to storage for monotonic -> boottime offset
2207 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2209 * Returns current monotonic time and updates the offsets if the
2210 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2213 * Called from hrtimer_interrupt() or retrigger_next_event()
2215 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2216 ktime_t *offs_boot, ktime_t *offs_tai)
2218 struct timekeeper *tk = &tk_core.timekeeper;
2224 seq = read_seqcount_begin(&tk_core.seq);
2226 base = tk->tkr_mono.base;
2227 nsecs = timekeeping_get_ns(&tk->tkr_mono);
2228 base = ktime_add_ns(base, nsecs);
2230 if (*cwsseq != tk->clock_was_set_seq) {
2231 *cwsseq = tk->clock_was_set_seq;
2232 *offs_real = tk->offs_real;
2233 *offs_boot = tk->offs_boot;
2234 *offs_tai = tk->offs_tai;
2237 /* Handle leapsecond insertion adjustments */
2238 if (unlikely(base >= tk->next_leap_ktime))
2239 *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2241 } while (read_seqcount_retry(&tk_core.seq, seq));
2247 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2249 int do_adjtimex(struct timex *txc)
2251 struct timekeeper *tk = &tk_core.timekeeper;
2252 unsigned long flags;
2253 struct timespec64 ts;
2257 /* Validate the data before disabling interrupts */
2258 ret = ntp_validate_timex(txc);
2262 if (txc->modes & ADJ_SETOFFSET) {
2263 struct timespec delta;
2264 delta.tv_sec = txc->time.tv_sec;
2265 delta.tv_nsec = txc->time.tv_usec;
2266 if (!(txc->modes & ADJ_NANO))
2267 delta.tv_nsec *= 1000;
2268 ret = timekeeping_inject_offset(&delta);
2273 getnstimeofday64(&ts);
2275 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2276 write_seqcount_begin(&tk_core.seq);
2278 orig_tai = tai = tk->tai_offset;
2279 ret = __do_adjtimex(txc, &ts, &tai);
2281 if (tai != orig_tai) {
2282 __timekeeping_set_tai_offset(tk, tai);
2283 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2285 tk_update_leap_state(tk);
2287 write_seqcount_end(&tk_core.seq);
2288 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2290 if (tai != orig_tai)
2293 ntp_notify_cmos_timer();
2298 #ifdef CONFIG_NTP_PPS
2300 * hardpps() - Accessor function to NTP __hardpps function
2302 void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2304 unsigned long flags;
2306 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2307 write_seqcount_begin(&tk_core.seq);
2309 __hardpps(phase_ts, raw_ts);
2311 write_seqcount_end(&tk_core.seq);
2312 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2314 EXPORT_SYMBOL(hardpps);
2318 * xtime_update() - advances the timekeeping infrastructure
2319 * @ticks: number of ticks, that have elapsed since the last call.
2321 * Must be called with interrupts disabled.
2323 void xtime_update(unsigned long ticks)
2325 write_seqlock(&jiffies_lock);
2327 write_sequnlock(&jiffies_lock);