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;
75 while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
76 tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
81 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
85 ts.tv_sec = tk->xtime_sec;
86 ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
90 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
92 tk->xtime_sec = ts->tv_sec;
93 tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
96 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
98 tk->xtime_sec += ts->tv_sec;
99 tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
100 tk_normalize_xtime(tk);
103 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
105 struct timespec64 tmp;
108 * Verify consistency of: offset_real = -wall_to_monotonic
109 * before modifying anything
111 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
112 -tk->wall_to_monotonic.tv_nsec);
113 WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
114 tk->wall_to_monotonic = wtm;
115 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
116 tk->offs_real = timespec64_to_ktime(tmp);
117 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
120 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
122 tk->offs_boot = ktime_add(tk->offs_boot, delta);
126 * tk_clock_read - atomic clocksource read() helper
128 * This helper is necessary to use in the read paths because, while the
129 * seqlock ensures we don't return a bad value while structures are updated,
130 * it doesn't protect from potential crashes. There is the possibility that
131 * the tkr's clocksource may change between the read reference, and the
132 * clock reference passed to the read function. This can cause crashes if
133 * the wrong clocksource is passed to the wrong read function.
134 * This isn't necessary to use when holding the timekeeper_lock or doing
135 * a read of the fast-timekeeper tkrs (which is protected by its own locking
138 static inline u64 tk_clock_read(struct tk_read_base *tkr)
140 struct clocksource *clock = READ_ONCE(tkr->clock);
142 return clock->read(clock);
145 #ifdef CONFIG_DEBUG_TIMEKEEPING
146 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
148 static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
151 u64 max_cycles = tk->tkr_mono.clock->max_cycles;
152 const char *name = tk->tkr_mono.clock->name;
154 if (offset > max_cycles) {
155 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
156 offset, name, max_cycles);
157 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
159 if (offset > (max_cycles >> 1)) {
160 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
161 offset, name, max_cycles >> 1);
162 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
166 if (tk->underflow_seen) {
167 if (jiffies - tk->last_warning > WARNING_FREQ) {
168 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
169 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
170 printk_deferred(" Your kernel is probably still fine.\n");
171 tk->last_warning = jiffies;
173 tk->underflow_seen = 0;
176 if (tk->overflow_seen) {
177 if (jiffies - tk->last_warning > WARNING_FREQ) {
178 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
179 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
180 printk_deferred(" Your kernel is probably still fine.\n");
181 tk->last_warning = jiffies;
183 tk->overflow_seen = 0;
187 static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
189 struct timekeeper *tk = &tk_core.timekeeper;
190 u64 now, last, mask, max, delta;
194 * Since we're called holding a seqlock, the data may shift
195 * under us while we're doing the calculation. This can cause
196 * false positives, since we'd note a problem but throw the
197 * results away. So nest another seqlock here to atomically
198 * grab the points we are checking with.
201 seq = read_seqcount_begin(&tk_core.seq);
202 now = tk_clock_read(tkr);
203 last = tkr->cycle_last;
205 max = tkr->clock->max_cycles;
206 } while (read_seqcount_retry(&tk_core.seq, seq));
208 delta = clocksource_delta(now, last, mask);
211 * Try to catch underflows by checking if we are seeing small
212 * mask-relative negative values.
214 if (unlikely((~delta & mask) < (mask >> 3))) {
215 tk->underflow_seen = 1;
219 /* Cap delta value to the max_cycles values to avoid mult overflows */
220 if (unlikely(delta > max)) {
221 tk->overflow_seen = 1;
222 delta = tkr->clock->max_cycles;
228 static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
231 static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
233 u64 cycle_now, delta;
235 /* read clocksource */
236 cycle_now = tk_clock_read(tkr);
238 /* calculate the delta since the last update_wall_time */
239 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
246 * tk_setup_internals - Set up internals to use clocksource clock.
248 * @tk: The target timekeeper to setup.
249 * @clock: Pointer to clocksource.
251 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
252 * pair and interval request.
254 * Unless you're the timekeeping code, you should not be using this!
256 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
259 u64 tmp, ntpinterval;
260 struct clocksource *old_clock;
262 ++tk->cs_was_changed_seq;
263 old_clock = tk->tkr_mono.clock;
264 tk->tkr_mono.clock = clock;
265 tk->tkr_mono.mask = clock->mask;
266 tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
268 tk->tkr_raw.clock = clock;
269 tk->tkr_raw.mask = clock->mask;
270 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
272 /* Do the ns -> cycle conversion first, using original mult */
273 tmp = NTP_INTERVAL_LENGTH;
274 tmp <<= clock->shift;
276 tmp += clock->mult/2;
277 do_div(tmp, clock->mult);
281 interval = (u64) tmp;
282 tk->cycle_interval = interval;
284 /* Go back from cycles -> shifted ns */
285 tk->xtime_interval = interval * clock->mult;
286 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
287 tk->raw_interval = interval * clock->mult;
289 /* if changing clocks, convert xtime_nsec shift units */
291 int shift_change = clock->shift - old_clock->shift;
292 if (shift_change < 0) {
293 tk->tkr_mono.xtime_nsec >>= -shift_change;
294 tk->tkr_raw.xtime_nsec >>= -shift_change;
296 tk->tkr_mono.xtime_nsec <<= shift_change;
297 tk->tkr_raw.xtime_nsec <<= shift_change;
301 tk->tkr_mono.shift = clock->shift;
302 tk->tkr_raw.shift = clock->shift;
305 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
306 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
309 * The timekeeper keeps its own mult values for the currently
310 * active clocksource. These value will be adjusted via NTP
311 * to counteract clock drifting.
313 tk->tkr_mono.mult = clock->mult;
314 tk->tkr_raw.mult = clock->mult;
315 tk->ntp_err_mult = 0;
318 /* Timekeeper helper functions. */
320 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
321 static u32 default_arch_gettimeoffset(void) { return 0; }
322 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
324 static inline u32 arch_gettimeoffset(void) { return 0; }
327 static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr, u64 delta)
331 nsec = delta * tkr->mult + tkr->xtime_nsec;
334 /* If arch requires, add in get_arch_timeoffset() */
335 return nsec + arch_gettimeoffset();
338 static inline u64 timekeeping_get_ns(struct tk_read_base *tkr)
342 delta = timekeeping_get_delta(tkr);
343 return timekeeping_delta_to_ns(tkr, delta);
346 static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr, u64 cycles)
350 /* calculate the delta since the last update_wall_time */
351 delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
352 return timekeeping_delta_to_ns(tkr, delta);
356 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
357 * @tkr: Timekeeping readout base from which we take the update
359 * We want to use this from any context including NMI and tracing /
360 * instrumenting the timekeeping code itself.
362 * Employ the latch technique; see @raw_write_seqcount_latch.
364 * So if a NMI hits the update of base[0] then it will use base[1]
365 * which is still consistent. In the worst case this can result is a
366 * slightly wrong timestamp (a few nanoseconds). See
367 * @ktime_get_mono_fast_ns.
369 static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
371 struct tk_read_base *base = tkf->base;
373 /* Force readers off to base[1] */
374 raw_write_seqcount_latch(&tkf->seq);
377 memcpy(base, tkr, sizeof(*base));
379 /* Force readers back to base[0] */
380 raw_write_seqcount_latch(&tkf->seq);
383 memcpy(base + 1, base, sizeof(*base));
387 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
389 * This timestamp is not guaranteed to be monotonic across an update.
390 * The timestamp is calculated by:
392 * now = base_mono + clock_delta * slope
394 * So if the update lowers the slope, readers who are forced to the
395 * not yet updated second array are still using the old steeper slope.
404 * |12345678---> reader order
410 * So reader 6 will observe time going backwards versus reader 5.
412 * While other CPUs are likely to be able observe that, the only way
413 * for a CPU local observation is when an NMI hits in the middle of
414 * the update. Timestamps taken from that NMI context might be ahead
415 * of the following timestamps. Callers need to be aware of that and
418 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
420 struct tk_read_base *tkr;
425 seq = raw_read_seqcount_latch(&tkf->seq);
426 tkr = tkf->base + (seq & 0x01);
427 now = ktime_to_ns(tkr->base);
429 now += timekeeping_delta_to_ns(tkr,
434 } while (read_seqcount_retry(&tkf->seq, seq));
439 u64 ktime_get_mono_fast_ns(void)
441 return __ktime_get_fast_ns(&tk_fast_mono);
443 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
445 u64 ktime_get_raw_fast_ns(void)
447 return __ktime_get_fast_ns(&tk_fast_raw);
449 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
452 * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
454 * To keep it NMI safe since we're accessing from tracing, we're not using a
455 * separate timekeeper with updates to monotonic clock and boot offset
456 * protected with seqlocks. This has the following minor side effects:
458 * (1) Its possible that a timestamp be taken after the boot offset is updated
459 * but before the timekeeper is updated. If this happens, the new boot offset
460 * is added to the old timekeeping making the clock appear to update slightly
463 * timekeeping_inject_sleeptime64()
464 * __timekeeping_inject_sleeptime(tk, delta);
466 * timekeeping_update(tk, TK_CLEAR_NTP...);
468 * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
469 * partially updated. Since the tk->offs_boot update is a rare event, this
470 * should be a rare occurrence which postprocessing should be able to handle.
472 u64 notrace ktime_get_boot_fast_ns(void)
474 struct timekeeper *tk = &tk_core.timekeeper;
476 return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
478 EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
480 /* Suspend-time cycles value for halted fast timekeeper. */
481 static u64 cycles_at_suspend;
483 static u64 dummy_clock_read(struct clocksource *cs)
485 return cycles_at_suspend;
488 static struct clocksource dummy_clock = {
489 .read = dummy_clock_read,
493 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
494 * @tk: Timekeeper to snapshot.
496 * It generally is unsafe to access the clocksource after timekeeping has been
497 * suspended, so take a snapshot of the readout base of @tk and use it as the
498 * fast timekeeper's readout base while suspended. It will return the same
499 * number of cycles every time until timekeeping is resumed at which time the
500 * proper readout base for the fast timekeeper will be restored automatically.
502 static void halt_fast_timekeeper(struct timekeeper *tk)
504 static struct tk_read_base tkr_dummy;
505 struct tk_read_base *tkr = &tk->tkr_mono;
507 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
508 cycles_at_suspend = tk_clock_read(tkr);
509 tkr_dummy.clock = &dummy_clock;
510 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
513 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
514 tkr_dummy.clock = &dummy_clock;
515 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
518 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
519 #warning Please contact your maintainers, as GENERIC_TIME_VSYSCALL_OLD compatibity will disappear soon.
521 static inline void update_vsyscall(struct timekeeper *tk)
523 struct timespec xt, wm;
525 xt = timespec64_to_timespec(tk_xtime(tk));
526 wm = timespec64_to_timespec(tk->wall_to_monotonic);
527 update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult,
528 tk->tkr_mono.cycle_last);
531 static inline void old_vsyscall_fixup(struct timekeeper *tk)
536 * Store only full nanoseconds into xtime_nsec after rounding
537 * it up and add the remainder to the error difference.
538 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
539 * by truncating the remainder in vsyscalls. However, it causes
540 * additional work to be done in timekeeping_adjust(). Once
541 * the vsyscall implementations are converted to use xtime_nsec
542 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
543 * users are removed, this can be killed.
545 remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1);
546 if (remainder != 0) {
547 tk->tkr_mono.xtime_nsec -= remainder;
548 tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift;
549 tk->ntp_error += remainder << tk->ntp_error_shift;
550 tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift;
554 #define old_vsyscall_fixup(tk)
557 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
559 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
561 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
565 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
567 int pvclock_gtod_register_notifier(struct notifier_block *nb)
569 struct timekeeper *tk = &tk_core.timekeeper;
573 raw_spin_lock_irqsave(&timekeeper_lock, flags);
574 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
575 update_pvclock_gtod(tk, true);
576 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
580 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
583 * pvclock_gtod_unregister_notifier - unregister a pvclock
584 * timedata update listener
586 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
591 raw_spin_lock_irqsave(&timekeeper_lock, flags);
592 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
593 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
597 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
600 * tk_update_leap_state - helper to update the next_leap_ktime
602 static inline void tk_update_leap_state(struct timekeeper *tk)
604 tk->next_leap_ktime = ntp_get_next_leap();
605 if (tk->next_leap_ktime != KTIME_MAX)
606 /* Convert to monotonic time */
607 tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
611 * Update the ktime_t based scalar nsec members of the timekeeper
613 static inline void tk_update_ktime_data(struct timekeeper *tk)
619 * The xtime based monotonic readout is:
620 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
621 * The ktime based monotonic readout is:
622 * nsec = base_mono + now();
623 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
625 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
626 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
627 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
630 * The sum of the nanoseconds portions of xtime and
631 * wall_to_monotonic can be greater/equal one second. Take
632 * this into account before updating tk->ktime_sec.
634 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
635 if (nsec >= NSEC_PER_SEC)
637 tk->ktime_sec = seconds;
639 /* Update the monotonic raw base */
640 seconds = tk->raw_sec;
641 nsec = (u32)(tk->tkr_raw.xtime_nsec >> tk->tkr_raw.shift);
642 tk->tkr_raw.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
645 /* must hold timekeeper_lock */
646 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
648 if (action & TK_CLEAR_NTP) {
653 tk_update_leap_state(tk);
654 tk_update_ktime_data(tk);
657 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
659 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
660 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
662 if (action & TK_CLOCK_WAS_SET)
663 tk->clock_was_set_seq++;
665 * The mirroring of the data to the shadow-timekeeper needs
666 * to happen last here to ensure we don't over-write the
667 * timekeeper structure on the next update with stale data
669 if (action & TK_MIRROR)
670 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
671 sizeof(tk_core.timekeeper));
675 * timekeeping_forward_now - update clock to the current time
677 * Forward the current clock to update its state since the last call to
678 * update_wall_time(). This is useful before significant clock changes,
679 * as it avoids having to deal with this time offset explicitly.
681 static void timekeeping_forward_now(struct timekeeper *tk)
683 u64 cycle_now, delta;
685 cycle_now = tk_clock_read(&tk->tkr_mono);
686 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
687 tk->tkr_mono.cycle_last = cycle_now;
688 tk->tkr_raw.cycle_last = cycle_now;
690 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
692 /* If arch requires, add in get_arch_timeoffset() */
693 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
696 tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;
698 /* If arch requires, add in get_arch_timeoffset() */
699 tk->tkr_raw.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_raw.shift;
701 tk_normalize_xtime(tk);
705 * __getnstimeofday64 - Returns the time of day in a timespec64.
706 * @ts: pointer to the timespec to be set
708 * Updates the time of day in the timespec.
709 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
711 int __getnstimeofday64(struct timespec64 *ts)
713 struct timekeeper *tk = &tk_core.timekeeper;
718 seq = read_seqcount_begin(&tk_core.seq);
720 ts->tv_sec = tk->xtime_sec;
721 nsecs = timekeeping_get_ns(&tk->tkr_mono);
723 } while (read_seqcount_retry(&tk_core.seq, seq));
726 timespec64_add_ns(ts, nsecs);
729 * Do not bail out early, in case there were callers still using
730 * the value, even in the face of the WARN_ON.
732 if (unlikely(timekeeping_suspended))
736 EXPORT_SYMBOL(__getnstimeofday64);
739 * getnstimeofday64 - Returns the time of day in a timespec64.
740 * @ts: pointer to the timespec64 to be set
742 * Returns the time of day in a timespec64 (WARN if suspended).
744 void getnstimeofday64(struct timespec64 *ts)
746 WARN_ON(__getnstimeofday64(ts));
748 EXPORT_SYMBOL(getnstimeofday64);
750 ktime_t ktime_get(void)
752 struct timekeeper *tk = &tk_core.timekeeper;
757 WARN_ON(timekeeping_suspended);
760 seq = read_seqcount_begin(&tk_core.seq);
761 base = tk->tkr_mono.base;
762 nsecs = timekeeping_get_ns(&tk->tkr_mono);
764 } while (read_seqcount_retry(&tk_core.seq, seq));
766 return ktime_add_ns(base, nsecs);
768 EXPORT_SYMBOL_GPL(ktime_get);
770 u32 ktime_get_resolution_ns(void)
772 struct timekeeper *tk = &tk_core.timekeeper;
776 WARN_ON(timekeeping_suspended);
779 seq = read_seqcount_begin(&tk_core.seq);
780 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
781 } while (read_seqcount_retry(&tk_core.seq, seq));
785 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
787 static ktime_t *offsets[TK_OFFS_MAX] = {
788 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
789 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
790 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
793 ktime_t ktime_get_with_offset(enum tk_offsets offs)
795 struct timekeeper *tk = &tk_core.timekeeper;
797 ktime_t base, *offset = offsets[offs];
800 WARN_ON(timekeeping_suspended);
803 seq = read_seqcount_begin(&tk_core.seq);
804 base = ktime_add(tk->tkr_mono.base, *offset);
805 nsecs = timekeeping_get_ns(&tk->tkr_mono);
807 } while (read_seqcount_retry(&tk_core.seq, seq));
809 return ktime_add_ns(base, nsecs);
812 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
815 * ktime_mono_to_any() - convert mononotic time to any other time
816 * @tmono: time to convert.
817 * @offs: which offset to use
819 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
821 ktime_t *offset = offsets[offs];
826 seq = read_seqcount_begin(&tk_core.seq);
827 tconv = ktime_add(tmono, *offset);
828 } while (read_seqcount_retry(&tk_core.seq, seq));
832 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
835 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
837 ktime_t ktime_get_raw(void)
839 struct timekeeper *tk = &tk_core.timekeeper;
845 seq = read_seqcount_begin(&tk_core.seq);
846 base = tk->tkr_raw.base;
847 nsecs = timekeeping_get_ns(&tk->tkr_raw);
849 } while (read_seqcount_retry(&tk_core.seq, seq));
851 return ktime_add_ns(base, nsecs);
853 EXPORT_SYMBOL_GPL(ktime_get_raw);
856 * ktime_get_ts64 - get the monotonic clock in timespec64 format
857 * @ts: pointer to timespec variable
859 * The function calculates the monotonic clock from the realtime
860 * clock and the wall_to_monotonic offset and stores the result
861 * in normalized timespec64 format in the variable pointed to by @ts.
863 void ktime_get_ts64(struct timespec64 *ts)
865 struct timekeeper *tk = &tk_core.timekeeper;
866 struct timespec64 tomono;
870 WARN_ON(timekeeping_suspended);
873 seq = read_seqcount_begin(&tk_core.seq);
874 ts->tv_sec = tk->xtime_sec;
875 nsec = timekeeping_get_ns(&tk->tkr_mono);
876 tomono = tk->wall_to_monotonic;
878 } while (read_seqcount_retry(&tk_core.seq, seq));
880 ts->tv_sec += tomono.tv_sec;
882 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
884 EXPORT_SYMBOL_GPL(ktime_get_ts64);
887 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
889 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
890 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
891 * works on both 32 and 64 bit systems. On 32 bit systems the readout
892 * covers ~136 years of uptime which should be enough to prevent
893 * premature wrap arounds.
895 time64_t ktime_get_seconds(void)
897 struct timekeeper *tk = &tk_core.timekeeper;
899 WARN_ON(timekeeping_suspended);
900 return tk->ktime_sec;
902 EXPORT_SYMBOL_GPL(ktime_get_seconds);
905 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
907 * Returns the wall clock seconds since 1970. This replaces the
908 * get_seconds() interface which is not y2038 safe on 32bit systems.
910 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
911 * 32bit systems the access must be protected with the sequence
912 * counter to provide "atomic" access to the 64bit tk->xtime_sec
915 time64_t ktime_get_real_seconds(void)
917 struct timekeeper *tk = &tk_core.timekeeper;
921 if (IS_ENABLED(CONFIG_64BIT))
922 return tk->xtime_sec;
925 seq = read_seqcount_begin(&tk_core.seq);
926 seconds = tk->xtime_sec;
928 } while (read_seqcount_retry(&tk_core.seq, seq));
932 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
935 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
936 * but without the sequence counter protect. This internal function
937 * is called just when timekeeping lock is already held.
939 time64_t __ktime_get_real_seconds(void)
941 struct timekeeper *tk = &tk_core.timekeeper;
943 return tk->xtime_sec;
947 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
948 * @systime_snapshot: pointer to struct receiving the system time snapshot
950 void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
952 struct timekeeper *tk = &tk_core.timekeeper;
960 WARN_ON_ONCE(timekeeping_suspended);
963 seq = read_seqcount_begin(&tk_core.seq);
964 now = tk_clock_read(&tk->tkr_mono);
965 systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
966 systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
967 base_real = ktime_add(tk->tkr_mono.base,
968 tk_core.timekeeper.offs_real);
969 base_raw = tk->tkr_raw.base;
970 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
971 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
972 } while (read_seqcount_retry(&tk_core.seq, seq));
974 systime_snapshot->cycles = now;
975 systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
976 systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
978 EXPORT_SYMBOL_GPL(ktime_get_snapshot);
980 /* Scale base by mult/div checking for overflow */
981 static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
985 tmp = div64_u64_rem(*base, div, &rem);
987 if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
988 ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
999 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
1000 * @history: Snapshot representing start of history
1001 * @partial_history_cycles: Cycle offset into history (fractional part)
1002 * @total_history_cycles: Total history length in cycles
1003 * @discontinuity: True indicates clock was set on history period
1004 * @ts: Cross timestamp that should be adjusted using
1005 * partial/total ratio
1007 * Helper function used by get_device_system_crosststamp() to correct the
1008 * crosstimestamp corresponding to the start of the current interval to the
1009 * system counter value (timestamp point) provided by the driver. The
1010 * total_history_* quantities are the total history starting at the provided
1011 * reference point and ending at the start of the current interval. The cycle
1012 * count between the driver timestamp point and the start of the current
1013 * interval is partial_history_cycles.
1015 static int adjust_historical_crosststamp(struct system_time_snapshot *history,
1016 u64 partial_history_cycles,
1017 u64 total_history_cycles,
1019 struct system_device_crosststamp *ts)
1021 struct timekeeper *tk = &tk_core.timekeeper;
1022 u64 corr_raw, corr_real;
1023 bool interp_forward;
1026 if (total_history_cycles == 0 || partial_history_cycles == 0)
1029 /* Interpolate shortest distance from beginning or end of history */
1030 interp_forward = partial_history_cycles > total_history_cycles / 2;
1031 partial_history_cycles = interp_forward ?
1032 total_history_cycles - partial_history_cycles :
1033 partial_history_cycles;
1036 * Scale the monotonic raw time delta by:
1037 * partial_history_cycles / total_history_cycles
1039 corr_raw = (u64)ktime_to_ns(
1040 ktime_sub(ts->sys_monoraw, history->raw));
1041 ret = scale64_check_overflow(partial_history_cycles,
1042 total_history_cycles, &corr_raw);
1047 * If there is a discontinuity in the history, scale monotonic raw
1049 * mult(real)/mult(raw) yielding the realtime correction
1050 * Otherwise, calculate the realtime correction similar to monotonic
1053 if (discontinuity) {
1054 corr_real = mul_u64_u32_div
1055 (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1057 corr_real = (u64)ktime_to_ns(
1058 ktime_sub(ts->sys_realtime, history->real));
1059 ret = scale64_check_overflow(partial_history_cycles,
1060 total_history_cycles, &corr_real);
1065 /* Fixup monotonic raw and real time time values */
1066 if (interp_forward) {
1067 ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1068 ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1070 ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1071 ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1078 * cycle_between - true if test occurs chronologically between before and after
1080 static bool cycle_between(u64 before, u64 test, u64 after)
1082 if (test > before && test < after)
1084 if (test < before && before > after)
1090 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1091 * @get_time_fn: Callback to get simultaneous device time and
1092 * system counter from the device driver
1093 * @ctx: Context passed to get_time_fn()
1094 * @history_begin: Historical reference point used to interpolate system
1095 * time when counter provided by the driver is before the current interval
1096 * @xtstamp: Receives simultaneously captured system and device time
1098 * Reads a timestamp from a device and correlates it to system time
1100 int get_device_system_crosststamp(int (*get_time_fn)
1101 (ktime_t *device_time,
1102 struct system_counterval_t *sys_counterval,
1105 struct system_time_snapshot *history_begin,
1106 struct system_device_crosststamp *xtstamp)
1108 struct system_counterval_t system_counterval;
1109 struct timekeeper *tk = &tk_core.timekeeper;
1110 u64 cycles, now, interval_start;
1111 unsigned int clock_was_set_seq = 0;
1112 ktime_t base_real, base_raw;
1113 u64 nsec_real, nsec_raw;
1114 u8 cs_was_changed_seq;
1120 seq = read_seqcount_begin(&tk_core.seq);
1122 * Try to synchronously capture device time and a system
1123 * counter value calling back into the device driver
1125 ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1130 * Verify that the clocksource associated with the captured
1131 * system counter value is the same as the currently installed
1132 * timekeeper clocksource
1134 if (tk->tkr_mono.clock != system_counterval.cs)
1136 cycles = system_counterval.cycles;
1139 * Check whether the system counter value provided by the
1140 * device driver is on the current timekeeping interval.
1142 now = tk_clock_read(&tk->tkr_mono);
1143 interval_start = tk->tkr_mono.cycle_last;
1144 if (!cycle_between(interval_start, cycles, now)) {
1145 clock_was_set_seq = tk->clock_was_set_seq;
1146 cs_was_changed_seq = tk->cs_was_changed_seq;
1147 cycles = interval_start;
1153 base_real = ktime_add(tk->tkr_mono.base,
1154 tk_core.timekeeper.offs_real);
1155 base_raw = tk->tkr_raw.base;
1157 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1158 system_counterval.cycles);
1159 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1160 system_counterval.cycles);
1161 } while (read_seqcount_retry(&tk_core.seq, seq));
1163 xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1164 xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1167 * Interpolate if necessary, adjusting back from the start of the
1171 u64 partial_history_cycles, total_history_cycles;
1175 * Check that the counter value occurs after the provided
1176 * history reference and that the history doesn't cross a
1177 * clocksource change
1179 if (!history_begin ||
1180 !cycle_between(history_begin->cycles,
1181 system_counterval.cycles, cycles) ||
1182 history_begin->cs_was_changed_seq != cs_was_changed_seq)
1184 partial_history_cycles = cycles - system_counterval.cycles;
1185 total_history_cycles = cycles - history_begin->cycles;
1187 history_begin->clock_was_set_seq != clock_was_set_seq;
1189 ret = adjust_historical_crosststamp(history_begin,
1190 partial_history_cycles,
1191 total_history_cycles,
1192 discontinuity, xtstamp);
1199 EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1202 * do_gettimeofday - Returns the time of day in a timeval
1203 * @tv: pointer to the timeval to be set
1205 * NOTE: Users should be converted to using getnstimeofday()
1207 void do_gettimeofday(struct timeval *tv)
1209 struct timespec64 now;
1211 getnstimeofday64(&now);
1212 tv->tv_sec = now.tv_sec;
1213 tv->tv_usec = now.tv_nsec/1000;
1215 EXPORT_SYMBOL(do_gettimeofday);
1218 * do_settimeofday64 - Sets the time of day.
1219 * @ts: pointer to the timespec64 variable containing the new time
1221 * Sets the time of day to the new time and update NTP and notify hrtimers
1223 int do_settimeofday64(const struct timespec64 *ts)
1225 struct timekeeper *tk = &tk_core.timekeeper;
1226 struct timespec64 ts_delta, xt;
1227 unsigned long flags;
1230 if (!timespec64_valid_strict(ts))
1233 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1234 write_seqcount_begin(&tk_core.seq);
1236 timekeeping_forward_now(tk);
1239 ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
1240 ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
1242 if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1247 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1249 tk_set_xtime(tk, ts);
1251 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1253 write_seqcount_end(&tk_core.seq);
1254 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1256 /* signal hrtimers about time change */
1261 EXPORT_SYMBOL(do_settimeofday64);
1264 * timekeeping_inject_offset - Adds or subtracts from the current time.
1265 * @tv: pointer to the timespec variable containing the offset
1267 * Adds or subtracts an offset value from the current time.
1269 int timekeeping_inject_offset(struct timespec *ts)
1271 struct timekeeper *tk = &tk_core.timekeeper;
1272 unsigned long flags;
1273 struct timespec64 ts64, tmp;
1276 if (!timespec_inject_offset_valid(ts))
1279 ts64 = timespec_to_timespec64(*ts);
1281 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1282 write_seqcount_begin(&tk_core.seq);
1284 timekeeping_forward_now(tk);
1286 /* Make sure the proposed value is valid */
1287 tmp = timespec64_add(tk_xtime(tk), ts64);
1288 if (timespec64_compare(&tk->wall_to_monotonic, &ts64) > 0 ||
1289 !timespec64_valid_strict(&tmp)) {
1294 tk_xtime_add(tk, &ts64);
1295 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
1297 error: /* even if we error out, we forwarded the time, so call update */
1298 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1300 write_seqcount_end(&tk_core.seq);
1301 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1303 /* signal hrtimers about time change */
1308 EXPORT_SYMBOL(timekeeping_inject_offset);
1311 * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
1314 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1316 tk->tai_offset = tai_offset;
1317 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1321 * change_clocksource - Swaps clocksources if a new one is available
1323 * Accumulates current time interval and initializes new clocksource
1325 static int change_clocksource(void *data)
1327 struct timekeeper *tk = &tk_core.timekeeper;
1328 struct clocksource *new, *old;
1329 unsigned long flags;
1331 new = (struct clocksource *) data;
1333 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1334 write_seqcount_begin(&tk_core.seq);
1336 timekeeping_forward_now(tk);
1338 * If the cs is in module, get a module reference. Succeeds
1339 * for built-in code (owner == NULL) as well.
1341 if (try_module_get(new->owner)) {
1342 if (!new->enable || new->enable(new) == 0) {
1343 old = tk->tkr_mono.clock;
1344 tk_setup_internals(tk, new);
1347 module_put(old->owner);
1349 module_put(new->owner);
1352 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1354 write_seqcount_end(&tk_core.seq);
1355 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1361 * timekeeping_notify - Install a new clock source
1362 * @clock: pointer to the clock source
1364 * This function is called from clocksource.c after a new, better clock
1365 * source has been registered. The caller holds the clocksource_mutex.
1367 int timekeeping_notify(struct clocksource *clock)
1369 struct timekeeper *tk = &tk_core.timekeeper;
1371 if (tk->tkr_mono.clock == clock)
1373 stop_machine(change_clocksource, clock, NULL);
1374 tick_clock_notify();
1375 return tk->tkr_mono.clock == clock ? 0 : -1;
1379 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1380 * @ts: pointer to the timespec64 to be set
1382 * Returns the raw monotonic time (completely un-modified by ntp)
1384 void getrawmonotonic64(struct timespec64 *ts)
1386 struct timekeeper *tk = &tk_core.timekeeper;
1391 seq = read_seqcount_begin(&tk_core.seq);
1392 ts->tv_sec = tk->raw_sec;
1393 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1395 } while (read_seqcount_retry(&tk_core.seq, seq));
1398 timespec64_add_ns(ts, 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);
1523 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1524 boot = tk_xtime(tk);
1526 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1527 tk_set_wall_to_mono(tk, tmp);
1529 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1531 write_seqcount_end(&tk_core.seq);
1532 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1535 /* time in seconds when suspend began for persistent clock */
1536 static struct timespec64 timekeeping_suspend_time;
1539 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1540 * @delta: pointer to a timespec delta value
1542 * Takes a timespec offset measuring a suspend interval and properly
1543 * adds the sleep offset to the timekeeping variables.
1545 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1546 struct timespec64 *delta)
1548 if (!timespec64_valid_strict(delta)) {
1549 printk_deferred(KERN_WARNING
1550 "__timekeeping_inject_sleeptime: Invalid "
1551 "sleep delta value!\n");
1554 tk_xtime_add(tk, delta);
1555 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1556 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1557 tk_debug_account_sleep_time(delta);
1560 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1562 * We have three kinds of time sources to use for sleep time
1563 * injection, the preference order is:
1564 * 1) non-stop clocksource
1565 * 2) persistent clock (ie: RTC accessible when irqs are off)
1568 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1569 * If system has neither 1) nor 2), 3) will be used finally.
1572 * If timekeeping has injected sleeptime via either 1) or 2),
1573 * 3) becomes needless, so in this case we don't need to call
1574 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1577 bool timekeeping_rtc_skipresume(void)
1579 return sleeptime_injected;
1583 * 1) can be determined whether to use or not only when doing
1584 * timekeeping_resume() which is invoked after rtc_suspend(),
1585 * so we can't skip rtc_suspend() surely if system has 1).
1587 * But if system has 2), 2) will definitely be used, so in this
1588 * case we don't need to call rtc_suspend(), and this is what
1589 * timekeeping_rtc_skipsuspend() means.
1591 bool timekeeping_rtc_skipsuspend(void)
1593 return persistent_clock_exists;
1597 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1598 * @delta: pointer to a timespec64 delta value
1600 * This hook is for architectures that cannot support read_persistent_clock64
1601 * because their RTC/persistent clock is only accessible when irqs are enabled.
1602 * and also don't have an effective nonstop clocksource.
1604 * This function should only be called by rtc_resume(), and allows
1605 * a suspend offset to be injected into the timekeeping values.
1607 void timekeeping_inject_sleeptime64(struct timespec64 *delta)
1609 struct timekeeper *tk = &tk_core.timekeeper;
1610 unsigned long flags;
1612 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1613 write_seqcount_begin(&tk_core.seq);
1615 timekeeping_forward_now(tk);
1617 __timekeeping_inject_sleeptime(tk, delta);
1619 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1621 write_seqcount_end(&tk_core.seq);
1622 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1624 /* signal hrtimers about time change */
1630 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1632 void timekeeping_resume(void)
1634 struct timekeeper *tk = &tk_core.timekeeper;
1635 struct clocksource *clock = tk->tkr_mono.clock;
1636 unsigned long flags;
1637 struct timespec64 ts_new, ts_delta;
1640 sleeptime_injected = false;
1641 read_persistent_clock64(&ts_new);
1643 clockevents_resume();
1644 clocksource_resume();
1646 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1647 write_seqcount_begin(&tk_core.seq);
1650 * After system resumes, we need to calculate the suspended time and
1651 * compensate it for the OS time. There are 3 sources that could be
1652 * used: Nonstop clocksource during suspend, persistent clock and rtc
1655 * One specific platform may have 1 or 2 or all of them, and the
1656 * preference will be:
1657 * suspend-nonstop clocksource -> persistent clock -> rtc
1658 * The less preferred source will only be tried if there is no better
1659 * usable source. The rtc part is handled separately in rtc core code.
1661 cycle_now = tk_clock_read(&tk->tkr_mono);
1662 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1663 cycle_now > tk->tkr_mono.cycle_last) {
1664 u64 nsec, cyc_delta;
1666 cyc_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
1668 nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift);
1669 ts_delta = ns_to_timespec64(nsec);
1670 sleeptime_injected = true;
1671 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1672 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1673 sleeptime_injected = true;
1676 if (sleeptime_injected)
1677 __timekeeping_inject_sleeptime(tk, &ts_delta);
1679 /* Re-base the last cycle value */
1680 tk->tkr_mono.cycle_last = cycle_now;
1681 tk->tkr_raw.cycle_last = cycle_now;
1684 timekeeping_suspended = 0;
1685 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1686 write_seqcount_end(&tk_core.seq);
1687 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1689 touch_softlockup_watchdog();
1695 int timekeeping_suspend(void)
1697 struct timekeeper *tk = &tk_core.timekeeper;
1698 unsigned long flags;
1699 struct timespec64 delta, delta_delta;
1700 static struct timespec64 old_delta;
1702 read_persistent_clock64(&timekeeping_suspend_time);
1705 * On some systems the persistent_clock can not be detected at
1706 * timekeeping_init by its return value, so if we see a valid
1707 * value returned, update the persistent_clock_exists flag.
1709 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1710 persistent_clock_exists = true;
1712 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1713 write_seqcount_begin(&tk_core.seq);
1714 timekeeping_forward_now(tk);
1715 timekeeping_suspended = 1;
1717 if (persistent_clock_exists) {
1719 * To avoid drift caused by repeated suspend/resumes,
1720 * which each can add ~1 second drift error,
1721 * try to compensate so the difference in system time
1722 * and persistent_clock time stays close to constant.
1724 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1725 delta_delta = timespec64_sub(delta, old_delta);
1726 if (abs(delta_delta.tv_sec) >= 2) {
1728 * if delta_delta is too large, assume time correction
1729 * has occurred and set old_delta to the current delta.
1733 /* Otherwise try to adjust old_system to compensate */
1734 timekeeping_suspend_time =
1735 timespec64_add(timekeeping_suspend_time, delta_delta);
1739 timekeeping_update(tk, TK_MIRROR);
1740 halt_fast_timekeeper(tk);
1741 write_seqcount_end(&tk_core.seq);
1742 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1745 clocksource_suspend();
1746 clockevents_suspend();
1751 /* sysfs resume/suspend bits for timekeeping */
1752 static struct syscore_ops timekeeping_syscore_ops = {
1753 .resume = timekeeping_resume,
1754 .suspend = timekeeping_suspend,
1757 static int __init timekeeping_init_ops(void)
1759 register_syscore_ops(&timekeeping_syscore_ops);
1762 device_initcall(timekeeping_init_ops);
1765 * Apply a multiplier adjustment to the timekeeper
1767 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1772 s64 interval = tk->cycle_interval;
1776 mult_adj = -mult_adj;
1777 interval = -interval;
1780 mult_adj <<= adj_scale;
1781 interval <<= adj_scale;
1782 offset <<= adj_scale;
1785 * So the following can be confusing.
1787 * To keep things simple, lets assume mult_adj == 1 for now.
1789 * When mult_adj != 1, remember that the interval and offset values
1790 * have been appropriately scaled so the math is the same.
1792 * The basic idea here is that we're increasing the multiplier
1793 * by one, this causes the xtime_interval to be incremented by
1794 * one cycle_interval. This is because:
1795 * xtime_interval = cycle_interval * mult
1796 * So if mult is being incremented by one:
1797 * xtime_interval = cycle_interval * (mult + 1)
1799 * xtime_interval = (cycle_interval * mult) + cycle_interval
1800 * Which can be shortened to:
1801 * xtime_interval += cycle_interval
1803 * So offset stores the non-accumulated cycles. Thus the current
1804 * time (in shifted nanoseconds) is:
1805 * now = (offset * adj) + xtime_nsec
1806 * Now, even though we're adjusting the clock frequency, we have
1807 * to keep time consistent. In other words, we can't jump back
1808 * in time, and we also want to avoid jumping forward in time.
1810 * So given the same offset value, we need the time to be the same
1811 * both before and after the freq adjustment.
1812 * now = (offset * adj_1) + xtime_nsec_1
1813 * now = (offset * adj_2) + xtime_nsec_2
1815 * (offset * adj_1) + xtime_nsec_1 =
1816 * (offset * adj_2) + xtime_nsec_2
1820 * (offset * adj_1) + xtime_nsec_1 =
1821 * (offset * (adj_1+1)) + xtime_nsec_2
1822 * (offset * adj_1) + xtime_nsec_1 =
1823 * (offset * adj_1) + offset + xtime_nsec_2
1824 * Canceling the sides:
1825 * xtime_nsec_1 = offset + xtime_nsec_2
1827 * xtime_nsec_2 = xtime_nsec_1 - offset
1828 * Which simplfies to:
1829 * xtime_nsec -= offset
1831 * XXX - TODO: Doc ntp_error calculation.
1833 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1834 /* NTP adjustment caused clocksource mult overflow */
1839 tk->tkr_mono.mult += mult_adj;
1840 tk->xtime_interval += interval;
1841 tk->tkr_mono.xtime_nsec -= offset;
1842 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1846 * Calculate the multiplier adjustment needed to match the frequency
1849 static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
1852 s64 interval = tk->cycle_interval;
1853 s64 xinterval = tk->xtime_interval;
1854 u32 base = tk->tkr_mono.clock->mult;
1855 u32 max = tk->tkr_mono.clock->maxadj;
1856 u32 cur_adj = tk->tkr_mono.mult;
1861 /* Remove any current error adj from freq calculation */
1862 if (tk->ntp_err_mult)
1863 xinterval -= tk->cycle_interval;
1865 tk->ntp_tick = ntp_tick_length();
1867 /* Calculate current error per tick */
1868 tick_error = ntp_tick_length() >> tk->ntp_error_shift;
1869 tick_error -= (xinterval + tk->xtime_remainder);
1871 /* Don't worry about correcting it if its small */
1872 if (likely((tick_error >= 0) && (tick_error <= interval)))
1875 /* preserve the direction of correction */
1876 negative = (tick_error < 0);
1878 /* If any adjustment would pass the max, just return */
1879 if (negative && (cur_adj - 1) <= (base - max))
1881 if (!negative && (cur_adj + 1) >= (base + max))
1884 * Sort out the magnitude of the correction, but
1885 * avoid making so large a correction that we go
1886 * over the max adjustment.
1889 tick_error = abs(tick_error);
1890 while (tick_error > interval) {
1891 u32 adj = 1 << (adj_scale + 1);
1893 /* Check if adjustment gets us within 1 unit from the max */
1894 if (negative && (cur_adj - adj) <= (base - max))
1896 if (!negative && (cur_adj + adj) >= (base + max))
1903 /* scale the corrections */
1904 timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
1908 * Adjust the timekeeper's multiplier to the correct frequency
1909 * and also to reduce the accumulated error value.
1911 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1913 /* Correct for the current frequency error */
1914 timekeeping_freqadjust(tk, offset);
1916 /* Next make a small adjustment to fix any cumulative error */
1917 if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
1918 tk->ntp_err_mult = 1;
1919 timekeeping_apply_adjustment(tk, offset, 0, 0);
1920 } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
1921 /* Undo any existing error adjustment */
1922 timekeeping_apply_adjustment(tk, offset, 1, 0);
1923 tk->ntp_err_mult = 0;
1926 if (unlikely(tk->tkr_mono.clock->maxadj &&
1927 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1928 > tk->tkr_mono.clock->maxadj))) {
1929 printk_once(KERN_WARNING
1930 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1931 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1932 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1936 * It may be possible that when we entered this function, xtime_nsec
1937 * was very small. Further, if we're slightly speeding the clocksource
1938 * in the code above, its possible the required corrective factor to
1939 * xtime_nsec could cause it to underflow.
1941 * Now, since we already accumulated the second, cannot simply roll
1942 * the accumulated second back, since the NTP subsystem has been
1943 * notified via second_overflow. So instead we push xtime_nsec forward
1944 * by the amount we underflowed, and add that amount into the error.
1946 * We'll correct this error next time through this function, when
1947 * xtime_nsec is not as small.
1949 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1950 s64 neg = -(s64)tk->tkr_mono.xtime_nsec;
1951 tk->tkr_mono.xtime_nsec = 0;
1952 tk->ntp_error += neg << tk->ntp_error_shift;
1957 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1959 * Helper function that accumulates the nsecs greater than a second
1960 * from the xtime_nsec field to the xtime_secs field.
1961 * It also calls into the NTP code to handle leapsecond processing.
1964 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1966 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1967 unsigned int clock_set = 0;
1969 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1972 tk->tkr_mono.xtime_nsec -= nsecps;
1975 /* Figure out if its a leap sec and apply if needed */
1976 leap = second_overflow(tk->xtime_sec);
1977 if (unlikely(leap)) {
1978 struct timespec64 ts;
1980 tk->xtime_sec += leap;
1984 tk_set_wall_to_mono(tk,
1985 timespec64_sub(tk->wall_to_monotonic, ts));
1987 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1989 clock_set = TK_CLOCK_WAS_SET;
1996 * logarithmic_accumulation - shifted accumulation of cycles
1998 * This functions accumulates a shifted interval of cycles into
1999 * into a shifted interval nanoseconds. Allows for O(log) accumulation
2002 * Returns the unconsumed cycles.
2004 static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
2005 u32 shift, unsigned int *clock_set)
2007 u64 interval = tk->cycle_interval << shift;
2010 /* If the offset is smaller than a shifted interval, do nothing */
2011 if (offset < interval)
2014 /* Accumulate one shifted interval */
2016 tk->tkr_mono.cycle_last += interval;
2017 tk->tkr_raw.cycle_last += interval;
2019 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2020 *clock_set |= accumulate_nsecs_to_secs(tk);
2022 /* Accumulate raw time */
2023 tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2024 snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2025 while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2026 tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2030 /* Accumulate error between NTP and clock interval */
2031 tk->ntp_error += tk->ntp_tick << shift;
2032 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2033 (tk->ntp_error_shift + shift);
2039 * update_wall_time - Uses the current clocksource to increment the wall time
2042 void update_wall_time(void)
2044 struct timekeeper *real_tk = &tk_core.timekeeper;
2045 struct timekeeper *tk = &shadow_timekeeper;
2047 int shift = 0, maxshift;
2048 unsigned int clock_set = 0;
2049 unsigned long flags;
2051 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2053 /* Make sure we're fully resumed: */
2054 if (unlikely(timekeeping_suspended))
2057 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2058 offset = real_tk->cycle_interval;
2060 offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2061 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2064 /* Check if there's really nothing to do */
2065 if (offset < real_tk->cycle_interval)
2068 /* Do some additional sanity checking */
2069 timekeeping_check_update(real_tk, offset);
2072 * With NO_HZ we may have to accumulate many cycle_intervals
2073 * (think "ticks") worth of time at once. To do this efficiently,
2074 * we calculate the largest doubling multiple of cycle_intervals
2075 * that is smaller than the offset. We then accumulate that
2076 * chunk in one go, and then try to consume the next smaller
2079 shift = ilog2(offset) - ilog2(tk->cycle_interval);
2080 shift = max(0, shift);
2081 /* Bound shift to one less than what overflows tick_length */
2082 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2083 shift = min(shift, maxshift);
2084 while (offset >= tk->cycle_interval) {
2085 offset = logarithmic_accumulation(tk, offset, shift,
2087 if (offset < tk->cycle_interval<<shift)
2091 /* correct the clock when NTP error is too big */
2092 timekeeping_adjust(tk, offset);
2095 * XXX This can be killed once everyone converts
2096 * to the new update_vsyscall.
2098 old_vsyscall_fixup(tk);
2101 * Finally, make sure that after the rounding
2102 * xtime_nsec isn't larger than NSEC_PER_SEC
2104 clock_set |= accumulate_nsecs_to_secs(tk);
2106 write_seqcount_begin(&tk_core.seq);
2108 * Update the real timekeeper.
2110 * We could avoid this memcpy by switching pointers, but that
2111 * requires changes to all other timekeeper usage sites as
2112 * well, i.e. move the timekeeper pointer getter into the
2113 * spinlocked/seqcount protected sections. And we trade this
2114 * memcpy under the tk_core.seq against one before we start
2117 timekeeping_update(tk, clock_set);
2118 memcpy(real_tk, tk, sizeof(*tk));
2119 /* The memcpy must come last. Do not put anything here! */
2120 write_seqcount_end(&tk_core.seq);
2122 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2124 /* Have to call _delayed version, since in irq context*/
2125 clock_was_set_delayed();
2129 * getboottime64 - Return the real time of system boot.
2130 * @ts: pointer to the timespec64 to be set
2132 * Returns the wall-time of boot in a timespec64.
2134 * This is based on the wall_to_monotonic offset and the total suspend
2135 * time. Calls to settimeofday will affect the value returned (which
2136 * basically means that however wrong your real time clock is at boot time,
2137 * you get the right time here).
2139 void getboottime64(struct timespec64 *ts)
2141 struct timekeeper *tk = &tk_core.timekeeper;
2142 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2144 *ts = ktime_to_timespec64(t);
2146 EXPORT_SYMBOL_GPL(getboottime64);
2148 unsigned long get_seconds(void)
2150 struct timekeeper *tk = &tk_core.timekeeper;
2152 return tk->xtime_sec;
2154 EXPORT_SYMBOL(get_seconds);
2156 struct timespec __current_kernel_time(void)
2158 struct timekeeper *tk = &tk_core.timekeeper;
2160 return timespec64_to_timespec(tk_xtime(tk));
2163 struct timespec64 current_kernel_time64(void)
2165 struct timekeeper *tk = &tk_core.timekeeper;
2166 struct timespec64 now;
2170 seq = read_seqcount_begin(&tk_core.seq);
2173 } while (read_seqcount_retry(&tk_core.seq, seq));
2177 EXPORT_SYMBOL(current_kernel_time64);
2179 struct timespec64 get_monotonic_coarse64(void)
2181 struct timekeeper *tk = &tk_core.timekeeper;
2182 struct timespec64 now, mono;
2186 seq = read_seqcount_begin(&tk_core.seq);
2189 mono = tk->wall_to_monotonic;
2190 } while (read_seqcount_retry(&tk_core.seq, seq));
2192 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
2193 now.tv_nsec + mono.tv_nsec);
2197 EXPORT_SYMBOL(get_monotonic_coarse64);
2200 * Must hold jiffies_lock
2202 void do_timer(unsigned long ticks)
2204 jiffies_64 += ticks;
2205 calc_global_load(ticks);
2209 * ktime_get_update_offsets_now - hrtimer helper
2210 * @cwsseq: pointer to check and store the clock was set sequence number
2211 * @offs_real: pointer to storage for monotonic -> realtime offset
2212 * @offs_boot: pointer to storage for monotonic -> boottime offset
2213 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2215 * Returns current monotonic time and updates the offsets if the
2216 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2219 * Called from hrtimer_interrupt() or retrigger_next_event()
2221 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2222 ktime_t *offs_boot, ktime_t *offs_tai)
2224 struct timekeeper *tk = &tk_core.timekeeper;
2230 seq = read_seqcount_begin(&tk_core.seq);
2232 base = tk->tkr_mono.base;
2233 nsecs = timekeeping_get_ns(&tk->tkr_mono);
2234 base = ktime_add_ns(base, nsecs);
2236 if (*cwsseq != tk->clock_was_set_seq) {
2237 *cwsseq = tk->clock_was_set_seq;
2238 *offs_real = tk->offs_real;
2239 *offs_boot = tk->offs_boot;
2240 *offs_tai = tk->offs_tai;
2243 /* Handle leapsecond insertion adjustments */
2244 if (unlikely(base >= tk->next_leap_ktime))
2245 *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2247 } while (read_seqcount_retry(&tk_core.seq, seq));
2253 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2255 int do_adjtimex(struct timex *txc)
2257 struct timekeeper *tk = &tk_core.timekeeper;
2258 unsigned long flags;
2259 struct timespec64 ts;
2263 /* Validate the data before disabling interrupts */
2264 ret = ntp_validate_timex(txc);
2268 if (txc->modes & ADJ_SETOFFSET) {
2269 struct timespec delta;
2270 delta.tv_sec = txc->time.tv_sec;
2271 delta.tv_nsec = txc->time.tv_usec;
2272 if (!(txc->modes & ADJ_NANO))
2273 delta.tv_nsec *= 1000;
2274 ret = timekeeping_inject_offset(&delta);
2279 getnstimeofday64(&ts);
2281 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2282 write_seqcount_begin(&tk_core.seq);
2284 orig_tai = tai = tk->tai_offset;
2285 ret = __do_adjtimex(txc, &ts, &tai);
2287 if (tai != orig_tai) {
2288 __timekeeping_set_tai_offset(tk, tai);
2289 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2291 tk_update_leap_state(tk);
2293 write_seqcount_end(&tk_core.seq);
2294 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2296 if (tai != orig_tai)
2299 ntp_notify_cmos_timer();
2304 #ifdef CONFIG_NTP_PPS
2306 * hardpps() - Accessor function to NTP __hardpps function
2308 void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2310 unsigned long flags;
2312 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2313 write_seqcount_begin(&tk_core.seq);
2315 __hardpps(phase_ts, raw_ts);
2317 write_seqcount_end(&tk_core.seq);
2318 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2320 EXPORT_SYMBOL(hardpps);
2324 * xtime_update() - advances the timekeeping infrastructure
2325 * @ticks: number of ticks, that have elapsed since the last call.
2327 * Must be called with interrupts disabled.
2329 void xtime_update(unsigned long ticks)
2331 write_seqlock(&jiffies_lock);
2333 write_sequnlock(&jiffies_lock);