2 * linux/kernel/time/timekeeping.c
4 * Kernel timekeeping code and accessor functions
6 * This code was moved from linux/kernel/timer.c.
7 * Please see that file for copyright and history logs.
11 #include <linux/timekeeper_internal.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include <linux/percpu.h>
15 #include <linux/init.h>
17 #include <linux/sched.h>
18 #include <linux/syscore_ops.h>
19 #include <linux/clocksource.h>
20 #include <linux/jiffies.h>
21 #include <linux/time.h>
22 #include <linux/tick.h>
23 #include <linux/stop_machine.h>
24 #include <linux/pvclock_gtod.h>
25 #include <linux/compiler.h>
27 #include "tick-internal.h"
28 #include "ntp_internal.h"
29 #include "timekeeping_internal.h"
31 #define TK_CLEAR_NTP (1 << 0)
32 #define TK_MIRROR (1 << 1)
33 #define TK_CLOCK_WAS_SET (1 << 2)
36 * The most important data for readout fits into a single 64 byte
41 struct timekeeper timekeeper
;
42 } tk_core ____cacheline_aligned
;
44 static DEFINE_RAW_SPINLOCK(timekeeper_lock
);
45 static struct timekeeper shadow_timekeeper
;
48 * struct tk_fast - NMI safe timekeeper
49 * @seq: Sequence counter for protecting updates. The lowest bit
50 * is the index for the tk_read_base array
51 * @base: tk_read_base array. Access is indexed by the lowest bit of
54 * See @update_fast_timekeeper() below.
58 struct tk_read_base base
[2];
61 static struct tk_fast tk_fast_mono ____cacheline_aligned
;
63 /* flag for if timekeeping is suspended */
64 int __read_mostly timekeeping_suspended
;
66 /* Flag for if there is a persistent clock on this platform */
67 bool __read_mostly persistent_clock_exist
= false;
69 static inline void tk_normalize_xtime(struct timekeeper
*tk
)
71 while (tk
->tkr
.xtime_nsec
>= ((u64
)NSEC_PER_SEC
<< tk
->tkr
.shift
)) {
72 tk
->tkr
.xtime_nsec
-= (u64
)NSEC_PER_SEC
<< tk
->tkr
.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
.xtime_nsec
>> tk
->tkr
.shift
);
86 static void tk_set_xtime(struct timekeeper
*tk
, const struct timespec64
*ts
)
88 tk
->xtime_sec
= ts
->tv_sec
;
89 tk
->tkr
.xtime_nsec
= (u64
)ts
->tv_nsec
<< tk
->tkr
.shift
;
92 static void tk_xtime_add(struct timekeeper
*tk
, const struct timespec64
*ts
)
94 tk
->xtime_sec
+= ts
->tv_sec
;
95 tk
->tkr
.xtime_nsec
+= (u64
)ts
->tv_nsec
<< tk
->tkr
.shift
;
96 tk_normalize_xtime(tk
);
99 static void tk_set_wall_to_mono(struct timekeeper
*tk
, struct timespec64 wtm
)
101 struct timespec64 tmp
;
104 * Verify consistency of: offset_real = -wall_to_monotonic
105 * before modifying anything
107 set_normalized_timespec64(&tmp
, -tk
->wall_to_monotonic
.tv_sec
,
108 -tk
->wall_to_monotonic
.tv_nsec
);
109 WARN_ON_ONCE(tk
->offs_real
.tv64
!= timespec64_to_ktime(tmp
).tv64
);
110 tk
->wall_to_monotonic
= wtm
;
111 set_normalized_timespec64(&tmp
, -wtm
.tv_sec
, -wtm
.tv_nsec
);
112 tk
->offs_real
= timespec64_to_ktime(tmp
);
113 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tk
->tai_offset
, 0));
116 static inline void tk_update_sleep_time(struct timekeeper
*tk
, ktime_t delta
)
118 tk
->offs_boot
= ktime_add(tk
->offs_boot
, delta
);
122 * tk_setup_internals - Set up internals to use clocksource clock.
124 * @tk: The target timekeeper to setup.
125 * @clock: Pointer to clocksource.
127 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
128 * pair and interval request.
130 * Unless you're the timekeeping code, you should not be using this!
132 static void tk_setup_internals(struct timekeeper
*tk
, struct clocksource
*clock
)
135 u64 tmp
, ntpinterval
;
136 struct clocksource
*old_clock
;
138 old_clock
= tk
->tkr
.clock
;
139 tk
->tkr
.clock
= clock
;
140 tk
->tkr
.read
= clock
->read
;
141 tk
->tkr
.mask
= clock
->mask
;
142 tk
->tkr
.cycle_last
= tk
->tkr
.read(clock
);
144 /* Do the ns -> cycle conversion first, using original mult */
145 tmp
= NTP_INTERVAL_LENGTH
;
146 tmp
<<= clock
->shift
;
148 tmp
+= clock
->mult
/2;
149 do_div(tmp
, clock
->mult
);
153 interval
= (cycle_t
) tmp
;
154 tk
->cycle_interval
= interval
;
156 /* Go back from cycles -> shifted ns */
157 tk
->xtime_interval
= (u64
) interval
* clock
->mult
;
158 tk
->xtime_remainder
= ntpinterval
- tk
->xtime_interval
;
160 ((u64
) interval
* clock
->mult
) >> clock
->shift
;
162 /* if changing clocks, convert xtime_nsec shift units */
164 int shift_change
= clock
->shift
- old_clock
->shift
;
165 if (shift_change
< 0)
166 tk
->tkr
.xtime_nsec
>>= -shift_change
;
168 tk
->tkr
.xtime_nsec
<<= shift_change
;
170 tk
->tkr
.shift
= clock
->shift
;
173 tk
->ntp_error_shift
= NTP_SCALE_SHIFT
- clock
->shift
;
174 tk
->ntp_tick
= ntpinterval
<< tk
->ntp_error_shift
;
177 * The timekeeper keeps its own mult values for the currently
178 * active clocksource. These value will be adjusted via NTP
179 * to counteract clock drifting.
181 tk
->tkr
.mult
= clock
->mult
;
182 tk
->ntp_err_mult
= 0;
185 /* Timekeeper helper functions. */
187 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
188 static u32
default_arch_gettimeoffset(void) { return 0; }
189 u32 (*arch_gettimeoffset
)(void) = default_arch_gettimeoffset
;
191 static inline u32
arch_gettimeoffset(void) { return 0; }
194 static inline s64
timekeeping_get_ns(struct tk_read_base
*tkr
)
196 cycle_t cycle_now
, delta
;
199 /* read clocksource: */
200 cycle_now
= tkr
->read(tkr
->clock
);
202 /* calculate the delta since the last update_wall_time: */
203 delta
= clocksource_delta(cycle_now
, tkr
->cycle_last
, tkr
->mask
);
205 nsec
= delta
* tkr
->mult
+ tkr
->xtime_nsec
;
208 /* If arch requires, add in get_arch_timeoffset() */
209 return nsec
+ arch_gettimeoffset();
212 static inline s64
timekeeping_get_ns_raw(struct timekeeper
*tk
)
214 struct clocksource
*clock
= tk
->tkr
.clock
;
215 cycle_t cycle_now
, delta
;
218 /* read clocksource: */
219 cycle_now
= tk
->tkr
.read(clock
);
221 /* calculate the delta since the last update_wall_time: */
222 delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
224 /* convert delta to nanoseconds. */
225 nsec
= clocksource_cyc2ns(delta
, clock
->mult
, clock
->shift
);
227 /* If arch requires, add in get_arch_timeoffset() */
228 return nsec
+ arch_gettimeoffset();
232 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
233 * @tkr: Timekeeping readout base from which we take the update
235 * We want to use this from any context including NMI and tracing /
236 * instrumenting the timekeeping code itself.
238 * So we handle this differently than the other timekeeping accessor
239 * functions which retry when the sequence count has changed. The
242 * smp_wmb(); <- Ensure that the last base[1] update is visible
244 * smp_wmb(); <- Ensure that the seqcount update is visible
245 * update(tkf->base[0], tkr);
246 * smp_wmb(); <- Ensure that the base[0] update is visible
248 * smp_wmb(); <- Ensure that the seqcount update is visible
249 * update(tkf->base[1], tkr);
251 * The reader side does:
257 * now = now(tkf->base[idx]);
259 * } while (seq != tkf->seq)
261 * As long as we update base[0] readers are forced off to
262 * base[1]. Once base[0] is updated readers are redirected to base[0]
263 * and the base[1] update takes place.
265 * So if a NMI hits the update of base[0] then it will use base[1]
266 * which is still consistent. In the worst case this can result is a
267 * slightly wrong timestamp (a few nanoseconds). See
268 * @ktime_get_mono_fast_ns.
270 static void update_fast_timekeeper(struct tk_read_base
*tkr
)
272 struct tk_read_base
*base
= tk_fast_mono
.base
;
274 /* Force readers off to base[1] */
275 raw_write_seqcount_latch(&tk_fast_mono
.seq
);
278 memcpy(base
, tkr
, sizeof(*base
));
280 /* Force readers back to base[0] */
281 raw_write_seqcount_latch(&tk_fast_mono
.seq
);
284 memcpy(base
+ 1, base
, sizeof(*base
));
288 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
290 * This timestamp is not guaranteed to be monotonic across an update.
291 * The timestamp is calculated by:
293 * now = base_mono + clock_delta * slope
295 * So if the update lowers the slope, readers who are forced to the
296 * not yet updated second array are still using the old steeper slope.
305 * |12345678---> reader order
311 * So reader 6 will observe time going backwards versus reader 5.
313 * While other CPUs are likely to be able observe that, the only way
314 * for a CPU local observation is when an NMI hits in the middle of
315 * the update. Timestamps taken from that NMI context might be ahead
316 * of the following timestamps. Callers need to be aware of that and
319 u64 notrace
ktime_get_mono_fast_ns(void)
321 struct tk_read_base
*tkr
;
326 seq
= raw_read_seqcount(&tk_fast_mono
.seq
);
327 tkr
= tk_fast_mono
.base
+ (seq
& 0x01);
328 now
= ktime_to_ns(tkr
->base_mono
) + timekeeping_get_ns(tkr
);
330 } while (read_seqcount_retry(&tk_fast_mono
.seq
, seq
));
333 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns
);
335 /* Suspend-time cycles value for halted fast timekeeper. */
336 static cycle_t cycles_at_suspend
;
338 static cycle_t
dummy_clock_read(struct clocksource
*cs
)
340 return cycles_at_suspend
;
344 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
345 * @tk: Timekeeper to snapshot.
347 * It generally is unsafe to access the clocksource after timekeeping has been
348 * suspended, so take a snapshot of the readout base of @tk and use it as the
349 * fast timekeeper's readout base while suspended. It will return the same
350 * number of cycles every time until timekeeping is resumed at which time the
351 * proper readout base for the fast timekeeper will be restored automatically.
353 static void halt_fast_timekeeper(struct timekeeper
*tk
)
355 static struct tk_read_base tkr_dummy
;
356 struct tk_read_base
*tkr
= &tk
->tkr
;
358 memcpy(&tkr_dummy
, tkr
, sizeof(tkr_dummy
));
359 cycles_at_suspend
= tkr
->read(tkr
->clock
);
360 tkr_dummy
.read
= dummy_clock_read
;
361 update_fast_timekeeper(&tkr_dummy
);
364 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
366 static inline void update_vsyscall(struct timekeeper
*tk
)
368 struct timespec xt
, wm
;
370 xt
= timespec64_to_timespec(tk_xtime(tk
));
371 wm
= timespec64_to_timespec(tk
->wall_to_monotonic
);
372 update_vsyscall_old(&xt
, &wm
, tk
->tkr
.clock
, tk
->tkr
.mult
,
376 static inline void old_vsyscall_fixup(struct timekeeper
*tk
)
381 * Store only full nanoseconds into xtime_nsec after rounding
382 * it up and add the remainder to the error difference.
383 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
384 * by truncating the remainder in vsyscalls. However, it causes
385 * additional work to be done in timekeeping_adjust(). Once
386 * the vsyscall implementations are converted to use xtime_nsec
387 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
388 * users are removed, this can be killed.
390 remainder
= tk
->tkr
.xtime_nsec
& ((1ULL << tk
->tkr
.shift
) - 1);
391 tk
->tkr
.xtime_nsec
-= remainder
;
392 tk
->tkr
.xtime_nsec
+= 1ULL << tk
->tkr
.shift
;
393 tk
->ntp_error
+= remainder
<< tk
->ntp_error_shift
;
394 tk
->ntp_error
-= (1ULL << tk
->tkr
.shift
) << tk
->ntp_error_shift
;
397 #define old_vsyscall_fixup(tk)
400 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain
);
402 static void update_pvclock_gtod(struct timekeeper
*tk
, bool was_set
)
404 raw_notifier_call_chain(&pvclock_gtod_chain
, was_set
, tk
);
408 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
410 int pvclock_gtod_register_notifier(struct notifier_block
*nb
)
412 struct timekeeper
*tk
= &tk_core
.timekeeper
;
416 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
417 ret
= raw_notifier_chain_register(&pvclock_gtod_chain
, nb
);
418 update_pvclock_gtod(tk
, true);
419 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
423 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier
);
426 * pvclock_gtod_unregister_notifier - unregister a pvclock
427 * timedata update listener
429 int pvclock_gtod_unregister_notifier(struct notifier_block
*nb
)
434 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
435 ret
= raw_notifier_chain_unregister(&pvclock_gtod_chain
, nb
);
436 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
440 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier
);
443 * Update the ktime_t based scalar nsec members of the timekeeper
445 static inline void tk_update_ktime_data(struct timekeeper
*tk
)
451 * The xtime based monotonic readout is:
452 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
453 * The ktime based monotonic readout is:
454 * nsec = base_mono + now();
455 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
457 seconds
= (u64
)(tk
->xtime_sec
+ tk
->wall_to_monotonic
.tv_sec
);
458 nsec
= (u32
) tk
->wall_to_monotonic
.tv_nsec
;
459 tk
->tkr
.base_mono
= ns_to_ktime(seconds
* NSEC_PER_SEC
+ nsec
);
461 /* Update the monotonic raw base */
462 tk
->base_raw
= timespec64_to_ktime(tk
->raw_time
);
465 * The sum of the nanoseconds portions of xtime and
466 * wall_to_monotonic can be greater/equal one second. Take
467 * this into account before updating tk->ktime_sec.
469 nsec
+= (u32
)(tk
->tkr
.xtime_nsec
>> tk
->tkr
.shift
);
470 if (nsec
>= NSEC_PER_SEC
)
472 tk
->ktime_sec
= seconds
;
475 /* must hold timekeeper_lock */
476 static void timekeeping_update(struct timekeeper
*tk
, unsigned int action
)
478 if (action
& TK_CLEAR_NTP
) {
483 tk_update_ktime_data(tk
);
486 update_pvclock_gtod(tk
, action
& TK_CLOCK_WAS_SET
);
488 if (action
& TK_MIRROR
)
489 memcpy(&shadow_timekeeper
, &tk_core
.timekeeper
,
490 sizeof(tk_core
.timekeeper
));
492 update_fast_timekeeper(&tk
->tkr
);
496 * timekeeping_forward_now - update clock to the current time
498 * Forward the current clock to update its state since the last call to
499 * update_wall_time(). This is useful before significant clock changes,
500 * as it avoids having to deal with this time offset explicitly.
502 static void timekeeping_forward_now(struct timekeeper
*tk
)
504 struct clocksource
*clock
= tk
->tkr
.clock
;
505 cycle_t cycle_now
, delta
;
508 cycle_now
= tk
->tkr
.read(clock
);
509 delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
510 tk
->tkr
.cycle_last
= cycle_now
;
512 tk
->tkr
.xtime_nsec
+= delta
* tk
->tkr
.mult
;
514 /* If arch requires, add in get_arch_timeoffset() */
515 tk
->tkr
.xtime_nsec
+= (u64
)arch_gettimeoffset() << tk
->tkr
.shift
;
517 tk_normalize_xtime(tk
);
519 nsec
= clocksource_cyc2ns(delta
, clock
->mult
, clock
->shift
);
520 timespec64_add_ns(&tk
->raw_time
, nsec
);
524 * __getnstimeofday64 - Returns the time of day in a timespec64.
525 * @ts: pointer to the timespec to be set
527 * Updates the time of day in the timespec.
528 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
530 int __getnstimeofday64(struct timespec64
*ts
)
532 struct timekeeper
*tk
= &tk_core
.timekeeper
;
537 seq
= read_seqcount_begin(&tk_core
.seq
);
539 ts
->tv_sec
= tk
->xtime_sec
;
540 nsecs
= timekeeping_get_ns(&tk
->tkr
);
542 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
545 timespec64_add_ns(ts
, nsecs
);
548 * Do not bail out early, in case there were callers still using
549 * the value, even in the face of the WARN_ON.
551 if (unlikely(timekeeping_suspended
))
555 EXPORT_SYMBOL(__getnstimeofday64
);
558 * getnstimeofday64 - Returns the time of day in a timespec64.
559 * @ts: pointer to the timespec64 to be set
561 * Returns the time of day in a timespec64 (WARN if suspended).
563 void getnstimeofday64(struct timespec64
*ts
)
565 WARN_ON(__getnstimeofday64(ts
));
567 EXPORT_SYMBOL(getnstimeofday64
);
569 ktime_t
ktime_get(void)
571 struct timekeeper
*tk
= &tk_core
.timekeeper
;
576 WARN_ON(timekeeping_suspended
);
579 seq
= read_seqcount_begin(&tk_core
.seq
);
580 base
= tk
->tkr
.base_mono
;
581 nsecs
= timekeeping_get_ns(&tk
->tkr
);
583 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
585 return ktime_add_ns(base
, nsecs
);
587 EXPORT_SYMBOL_GPL(ktime_get
);
589 static ktime_t
*offsets
[TK_OFFS_MAX
] = {
590 [TK_OFFS_REAL
] = &tk_core
.timekeeper
.offs_real
,
591 [TK_OFFS_BOOT
] = &tk_core
.timekeeper
.offs_boot
,
592 [TK_OFFS_TAI
] = &tk_core
.timekeeper
.offs_tai
,
595 ktime_t
ktime_get_with_offset(enum tk_offsets offs
)
597 struct timekeeper
*tk
= &tk_core
.timekeeper
;
599 ktime_t base
, *offset
= offsets
[offs
];
602 WARN_ON(timekeeping_suspended
);
605 seq
= read_seqcount_begin(&tk_core
.seq
);
606 base
= ktime_add(tk
->tkr
.base_mono
, *offset
);
607 nsecs
= timekeeping_get_ns(&tk
->tkr
);
609 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
611 return ktime_add_ns(base
, nsecs
);
614 EXPORT_SYMBOL_GPL(ktime_get_with_offset
);
617 * ktime_mono_to_any() - convert mononotic time to any other time
618 * @tmono: time to convert.
619 * @offs: which offset to use
621 ktime_t
ktime_mono_to_any(ktime_t tmono
, enum tk_offsets offs
)
623 ktime_t
*offset
= offsets
[offs
];
628 seq
= read_seqcount_begin(&tk_core
.seq
);
629 tconv
= ktime_add(tmono
, *offset
);
630 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
634 EXPORT_SYMBOL_GPL(ktime_mono_to_any
);
637 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
639 ktime_t
ktime_get_raw(void)
641 struct timekeeper
*tk
= &tk_core
.timekeeper
;
647 seq
= read_seqcount_begin(&tk_core
.seq
);
649 nsecs
= timekeeping_get_ns_raw(tk
);
651 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
653 return ktime_add_ns(base
, nsecs
);
655 EXPORT_SYMBOL_GPL(ktime_get_raw
);
658 * ktime_get_ts64 - get the monotonic clock in timespec64 format
659 * @ts: pointer to timespec variable
661 * The function calculates the monotonic clock from the realtime
662 * clock and the wall_to_monotonic offset and stores the result
663 * in normalized timespec64 format in the variable pointed to by @ts.
665 void ktime_get_ts64(struct timespec64
*ts
)
667 struct timekeeper
*tk
= &tk_core
.timekeeper
;
668 struct timespec64 tomono
;
672 WARN_ON(timekeeping_suspended
);
675 seq
= read_seqcount_begin(&tk_core
.seq
);
676 ts
->tv_sec
= tk
->xtime_sec
;
677 nsec
= timekeeping_get_ns(&tk
->tkr
);
678 tomono
= tk
->wall_to_monotonic
;
680 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
682 ts
->tv_sec
+= tomono
.tv_sec
;
684 timespec64_add_ns(ts
, nsec
+ tomono
.tv_nsec
);
686 EXPORT_SYMBOL_GPL(ktime_get_ts64
);
689 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
691 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
692 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
693 * works on both 32 and 64 bit systems. On 32 bit systems the readout
694 * covers ~136 years of uptime which should be enough to prevent
695 * premature wrap arounds.
697 time64_t
ktime_get_seconds(void)
699 struct timekeeper
*tk
= &tk_core
.timekeeper
;
701 WARN_ON(timekeeping_suspended
);
702 return tk
->ktime_sec
;
704 EXPORT_SYMBOL_GPL(ktime_get_seconds
);
707 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
709 * Returns the wall clock seconds since 1970. This replaces the
710 * get_seconds() interface which is not y2038 safe on 32bit systems.
712 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
713 * 32bit systems the access must be protected with the sequence
714 * counter to provide "atomic" access to the 64bit tk->xtime_sec
717 time64_t
ktime_get_real_seconds(void)
719 struct timekeeper
*tk
= &tk_core
.timekeeper
;
723 if (IS_ENABLED(CONFIG_64BIT
))
724 return tk
->xtime_sec
;
727 seq
= read_seqcount_begin(&tk_core
.seq
);
728 seconds
= tk
->xtime_sec
;
730 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
734 EXPORT_SYMBOL_GPL(ktime_get_real_seconds
);
736 #ifdef CONFIG_NTP_PPS
739 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
740 * @ts_raw: pointer to the timespec to be set to raw monotonic time
741 * @ts_real: pointer to the timespec to be set to the time of day
743 * This function reads both the time of day and raw monotonic time at the
744 * same time atomically and stores the resulting timestamps in timespec
747 void getnstime_raw_and_real(struct timespec
*ts_raw
, struct timespec
*ts_real
)
749 struct timekeeper
*tk
= &tk_core
.timekeeper
;
751 s64 nsecs_raw
, nsecs_real
;
753 WARN_ON_ONCE(timekeeping_suspended
);
756 seq
= read_seqcount_begin(&tk_core
.seq
);
758 *ts_raw
= timespec64_to_timespec(tk
->raw_time
);
759 ts_real
->tv_sec
= tk
->xtime_sec
;
760 ts_real
->tv_nsec
= 0;
762 nsecs_raw
= timekeeping_get_ns_raw(tk
);
763 nsecs_real
= timekeeping_get_ns(&tk
->tkr
);
765 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
767 timespec_add_ns(ts_raw
, nsecs_raw
);
768 timespec_add_ns(ts_real
, nsecs_real
);
770 EXPORT_SYMBOL(getnstime_raw_and_real
);
772 #endif /* CONFIG_NTP_PPS */
775 * do_gettimeofday - Returns the time of day in a timeval
776 * @tv: pointer to the timeval to be set
778 * NOTE: Users should be converted to using getnstimeofday()
780 void do_gettimeofday(struct timeval
*tv
)
782 struct timespec64 now
;
784 getnstimeofday64(&now
);
785 tv
->tv_sec
= now
.tv_sec
;
786 tv
->tv_usec
= now
.tv_nsec
/1000;
788 EXPORT_SYMBOL(do_gettimeofday
);
791 * do_settimeofday64 - Sets the time of day.
792 * @ts: pointer to the timespec64 variable containing the new time
794 * Sets the time of day to the new time and update NTP and notify hrtimers
796 int do_settimeofday64(const struct timespec64
*ts
)
798 struct timekeeper
*tk
= &tk_core
.timekeeper
;
799 struct timespec64 ts_delta
, xt
;
802 if (!timespec64_valid_strict(ts
))
805 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
806 write_seqcount_begin(&tk_core
.seq
);
808 timekeeping_forward_now(tk
);
811 ts_delta
.tv_sec
= ts
->tv_sec
- xt
.tv_sec
;
812 ts_delta
.tv_nsec
= ts
->tv_nsec
- xt
.tv_nsec
;
814 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts_delta
));
816 tk_set_xtime(tk
, ts
);
818 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
820 write_seqcount_end(&tk_core
.seq
);
821 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
823 /* signal hrtimers about time change */
828 EXPORT_SYMBOL(do_settimeofday64
);
831 * timekeeping_inject_offset - Adds or subtracts from the current time.
832 * @tv: pointer to the timespec variable containing the offset
834 * Adds or subtracts an offset value from the current time.
836 int timekeeping_inject_offset(struct timespec
*ts
)
838 struct timekeeper
*tk
= &tk_core
.timekeeper
;
840 struct timespec64 ts64
, tmp
;
843 if ((unsigned long)ts
->tv_nsec
>= NSEC_PER_SEC
)
846 ts64
= timespec_to_timespec64(*ts
);
848 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
849 write_seqcount_begin(&tk_core
.seq
);
851 timekeeping_forward_now(tk
);
853 /* Make sure the proposed value is valid */
854 tmp
= timespec64_add(tk_xtime(tk
), ts64
);
855 if (!timespec64_valid_strict(&tmp
)) {
860 tk_xtime_add(tk
, &ts64
);
861 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts64
));
863 error
: /* even if we error out, we forwarded the time, so call update */
864 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
866 write_seqcount_end(&tk_core
.seq
);
867 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
869 /* signal hrtimers about time change */
874 EXPORT_SYMBOL(timekeeping_inject_offset
);
878 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
881 s32
timekeeping_get_tai_offset(void)
883 struct timekeeper
*tk
= &tk_core
.timekeeper
;
888 seq
= read_seqcount_begin(&tk_core
.seq
);
889 ret
= tk
->tai_offset
;
890 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
896 * __timekeeping_set_tai_offset - Lock free worker function
899 static void __timekeeping_set_tai_offset(struct timekeeper
*tk
, s32 tai_offset
)
901 tk
->tai_offset
= tai_offset
;
902 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tai_offset
, 0));
906 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
909 void timekeeping_set_tai_offset(s32 tai_offset
)
911 struct timekeeper
*tk
= &tk_core
.timekeeper
;
914 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
915 write_seqcount_begin(&tk_core
.seq
);
916 __timekeeping_set_tai_offset(tk
, tai_offset
);
917 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
918 write_seqcount_end(&tk_core
.seq
);
919 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
924 * change_clocksource - Swaps clocksources if a new one is available
926 * Accumulates current time interval and initializes new clocksource
928 static int change_clocksource(void *data
)
930 struct timekeeper
*tk
= &tk_core
.timekeeper
;
931 struct clocksource
*new, *old
;
934 new = (struct clocksource
*) data
;
936 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
937 write_seqcount_begin(&tk_core
.seq
);
939 timekeeping_forward_now(tk
);
941 * If the cs is in module, get a module reference. Succeeds
942 * for built-in code (owner == NULL) as well.
944 if (try_module_get(new->owner
)) {
945 if (!new->enable
|| new->enable(new) == 0) {
947 tk_setup_internals(tk
, new);
950 module_put(old
->owner
);
952 module_put(new->owner
);
955 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
957 write_seqcount_end(&tk_core
.seq
);
958 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
964 * timekeeping_notify - Install a new clock source
965 * @clock: pointer to the clock source
967 * This function is called from clocksource.c after a new, better clock
968 * source has been registered. The caller holds the clocksource_mutex.
970 int timekeeping_notify(struct clocksource
*clock
)
972 struct timekeeper
*tk
= &tk_core
.timekeeper
;
974 if (tk
->tkr
.clock
== clock
)
976 stop_machine(change_clocksource
, clock
, NULL
);
978 return tk
->tkr
.clock
== clock
? 0 : -1;
982 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
983 * @ts: pointer to the timespec64 to be set
985 * Returns the raw monotonic time (completely un-modified by ntp)
987 void getrawmonotonic64(struct timespec64
*ts
)
989 struct timekeeper
*tk
= &tk_core
.timekeeper
;
990 struct timespec64 ts64
;
995 seq
= read_seqcount_begin(&tk_core
.seq
);
996 nsecs
= timekeeping_get_ns_raw(tk
);
999 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1001 timespec64_add_ns(&ts64
, nsecs
);
1004 EXPORT_SYMBOL(getrawmonotonic64
);
1008 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1010 int timekeeping_valid_for_hres(void)
1012 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1017 seq
= read_seqcount_begin(&tk_core
.seq
);
1019 ret
= tk
->tkr
.clock
->flags
& CLOCK_SOURCE_VALID_FOR_HRES
;
1021 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1027 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1029 u64
timekeeping_max_deferment(void)
1031 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1036 seq
= read_seqcount_begin(&tk_core
.seq
);
1038 ret
= tk
->tkr
.clock
->max_idle_ns
;
1040 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1046 * read_persistent_clock - Return time from the persistent clock.
1048 * Weak dummy function for arches that do not yet support it.
1049 * Reads the time from the battery backed persistent clock.
1050 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1052 * XXX - Do be sure to remove it once all arches implement it.
1054 void __weak
read_persistent_clock(struct timespec
*ts
)
1061 * read_boot_clock - Return time of the system start.
1063 * Weak dummy function for arches that do not yet support it.
1064 * Function to read the exact time the system has been started.
1065 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1067 * XXX - Do be sure to remove it once all arches implement it.
1069 void __weak
read_boot_clock(struct timespec
*ts
)
1076 * timekeeping_init - Initializes the clocksource and common timekeeping values
1078 void __init
timekeeping_init(void)
1080 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1081 struct clocksource
*clock
;
1082 unsigned long flags
;
1083 struct timespec64 now
, boot
, tmp
;
1086 read_persistent_clock(&ts
);
1087 now
= timespec_to_timespec64(ts
);
1088 if (!timespec64_valid_strict(&now
)) {
1089 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1090 " Check your CMOS/BIOS settings.\n");
1093 } else if (now
.tv_sec
|| now
.tv_nsec
)
1094 persistent_clock_exist
= true;
1096 read_boot_clock(&ts
);
1097 boot
= timespec_to_timespec64(ts
);
1098 if (!timespec64_valid_strict(&boot
)) {
1099 pr_warn("WARNING: Boot clock returned invalid value!\n"
1100 " Check your CMOS/BIOS settings.\n");
1105 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1106 write_seqcount_begin(&tk_core
.seq
);
1109 clock
= clocksource_default_clock();
1111 clock
->enable(clock
);
1112 tk_setup_internals(tk
, clock
);
1114 tk_set_xtime(tk
, &now
);
1115 tk
->raw_time
.tv_sec
= 0;
1116 tk
->raw_time
.tv_nsec
= 0;
1117 tk
->base_raw
.tv64
= 0;
1118 if (boot
.tv_sec
== 0 && boot
.tv_nsec
== 0)
1119 boot
= tk_xtime(tk
);
1121 set_normalized_timespec64(&tmp
, -boot
.tv_sec
, -boot
.tv_nsec
);
1122 tk_set_wall_to_mono(tk
, tmp
);
1124 timekeeping_update(tk
, TK_MIRROR
);
1126 write_seqcount_end(&tk_core
.seq
);
1127 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1130 /* time in seconds when suspend began */
1131 static struct timespec64 timekeeping_suspend_time
;
1134 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1135 * @delta: pointer to a timespec delta value
1137 * Takes a timespec offset measuring a suspend interval and properly
1138 * adds the sleep offset to the timekeeping variables.
1140 static void __timekeeping_inject_sleeptime(struct timekeeper
*tk
,
1141 struct timespec64
*delta
)
1143 if (!timespec64_valid_strict(delta
)) {
1144 printk_deferred(KERN_WARNING
1145 "__timekeeping_inject_sleeptime: Invalid "
1146 "sleep delta value!\n");
1149 tk_xtime_add(tk
, delta
);
1150 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, *delta
));
1151 tk_update_sleep_time(tk
, timespec64_to_ktime(*delta
));
1152 tk_debug_account_sleep_time(delta
);
1156 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1157 * @delta: pointer to a timespec64 delta value
1159 * This hook is for architectures that cannot support read_persistent_clock
1160 * because their RTC/persistent clock is only accessible when irqs are enabled.
1162 * This function should only be called by rtc_resume(), and allows
1163 * a suspend offset to be injected into the timekeeping values.
1165 void timekeeping_inject_sleeptime64(struct timespec64
*delta
)
1167 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1168 unsigned long flags
;
1171 * Make sure we don't set the clock twice, as timekeeping_resume()
1174 if (has_persistent_clock())
1177 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1178 write_seqcount_begin(&tk_core
.seq
);
1180 timekeeping_forward_now(tk
);
1182 __timekeeping_inject_sleeptime(tk
, delta
);
1184 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
1186 write_seqcount_end(&tk_core
.seq
);
1187 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1189 /* signal hrtimers about time change */
1194 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1196 * This is for the generic clocksource timekeeping.
1197 * xtime/wall_to_monotonic/jiffies/etc are
1198 * still managed by arch specific suspend/resume code.
1200 void timekeeping_resume(void)
1202 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1203 struct clocksource
*clock
= tk
->tkr
.clock
;
1204 unsigned long flags
;
1205 struct timespec64 ts_new
, ts_delta
;
1206 struct timespec tmp
;
1207 cycle_t cycle_now
, cycle_delta
;
1208 bool suspendtime_found
= false;
1210 read_persistent_clock(&tmp
);
1211 ts_new
= timespec_to_timespec64(tmp
);
1213 clockevents_resume();
1214 clocksource_resume();
1216 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1217 write_seqcount_begin(&tk_core
.seq
);
1220 * After system resumes, we need to calculate the suspended time and
1221 * compensate it for the OS time. There are 3 sources that could be
1222 * used: Nonstop clocksource during suspend, persistent clock and rtc
1225 * One specific platform may have 1 or 2 or all of them, and the
1226 * preference will be:
1227 * suspend-nonstop clocksource -> persistent clock -> rtc
1228 * The less preferred source will only be tried if there is no better
1229 * usable source. The rtc part is handled separately in rtc core code.
1231 cycle_now
= tk
->tkr
.read(clock
);
1232 if ((clock
->flags
& CLOCK_SOURCE_SUSPEND_NONSTOP
) &&
1233 cycle_now
> tk
->tkr
.cycle_last
) {
1234 u64 num
, max
= ULLONG_MAX
;
1235 u32 mult
= clock
->mult
;
1236 u32 shift
= clock
->shift
;
1239 cycle_delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
,
1243 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1244 * suspended time is too long. In that case we need do the
1245 * 64 bits math carefully
1248 if (cycle_delta
> max
) {
1249 num
= div64_u64(cycle_delta
, max
);
1250 nsec
= (((u64
) max
* mult
) >> shift
) * num
;
1251 cycle_delta
-= num
* max
;
1253 nsec
+= ((u64
) cycle_delta
* mult
) >> shift
;
1255 ts_delta
= ns_to_timespec64(nsec
);
1256 suspendtime_found
= true;
1257 } else if (timespec64_compare(&ts_new
, &timekeeping_suspend_time
) > 0) {
1258 ts_delta
= timespec64_sub(ts_new
, timekeeping_suspend_time
);
1259 suspendtime_found
= true;
1262 if (suspendtime_found
)
1263 __timekeeping_inject_sleeptime(tk
, &ts_delta
);
1265 /* Re-base the last cycle value */
1266 tk
->tkr
.cycle_last
= cycle_now
;
1268 timekeeping_suspended
= 0;
1269 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1270 write_seqcount_end(&tk_core
.seq
);
1271 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1273 touch_softlockup_watchdog();
1275 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME
, NULL
);
1277 /* Resume hrtimers */
1281 int timekeeping_suspend(void)
1283 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1284 unsigned long flags
;
1285 struct timespec64 delta
, delta_delta
;
1286 static struct timespec64 old_delta
;
1287 struct timespec tmp
;
1289 read_persistent_clock(&tmp
);
1290 timekeeping_suspend_time
= timespec_to_timespec64(tmp
);
1293 * On some systems the persistent_clock can not be detected at
1294 * timekeeping_init by its return value, so if we see a valid
1295 * value returned, update the persistent_clock_exists flag.
1297 if (timekeeping_suspend_time
.tv_sec
|| timekeeping_suspend_time
.tv_nsec
)
1298 persistent_clock_exist
= true;
1300 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1301 write_seqcount_begin(&tk_core
.seq
);
1302 timekeeping_forward_now(tk
);
1303 timekeeping_suspended
= 1;
1306 * To avoid drift caused by repeated suspend/resumes,
1307 * which each can add ~1 second drift error,
1308 * try to compensate so the difference in system time
1309 * and persistent_clock time stays close to constant.
1311 delta
= timespec64_sub(tk_xtime(tk
), timekeeping_suspend_time
);
1312 delta_delta
= timespec64_sub(delta
, old_delta
);
1313 if (abs(delta_delta
.tv_sec
) >= 2) {
1315 * if delta_delta is too large, assume time correction
1316 * has occured and set old_delta to the current delta.
1320 /* Otherwise try to adjust old_system to compensate */
1321 timekeeping_suspend_time
=
1322 timespec64_add(timekeeping_suspend_time
, delta_delta
);
1325 timekeeping_update(tk
, TK_MIRROR
);
1326 halt_fast_timekeeper(tk
);
1327 write_seqcount_end(&tk_core
.seq
);
1328 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1330 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND
, NULL
);
1331 clocksource_suspend();
1332 clockevents_suspend();
1337 /* sysfs resume/suspend bits for timekeeping */
1338 static struct syscore_ops timekeeping_syscore_ops
= {
1339 .resume
= timekeeping_resume
,
1340 .suspend
= timekeeping_suspend
,
1343 static int __init
timekeeping_init_ops(void)
1345 register_syscore_ops(&timekeeping_syscore_ops
);
1348 device_initcall(timekeeping_init_ops
);
1351 * Apply a multiplier adjustment to the timekeeper
1353 static __always_inline
void timekeeping_apply_adjustment(struct timekeeper
*tk
,
1358 s64 interval
= tk
->cycle_interval
;
1362 mult_adj
= -mult_adj
;
1363 interval
= -interval
;
1366 mult_adj
<<= adj_scale
;
1367 interval
<<= adj_scale
;
1368 offset
<<= adj_scale
;
1371 * So the following can be confusing.
1373 * To keep things simple, lets assume mult_adj == 1 for now.
1375 * When mult_adj != 1, remember that the interval and offset values
1376 * have been appropriately scaled so the math is the same.
1378 * The basic idea here is that we're increasing the multiplier
1379 * by one, this causes the xtime_interval to be incremented by
1380 * one cycle_interval. This is because:
1381 * xtime_interval = cycle_interval * mult
1382 * So if mult is being incremented by one:
1383 * xtime_interval = cycle_interval * (mult + 1)
1385 * xtime_interval = (cycle_interval * mult) + cycle_interval
1386 * Which can be shortened to:
1387 * xtime_interval += cycle_interval
1389 * So offset stores the non-accumulated cycles. Thus the current
1390 * time (in shifted nanoseconds) is:
1391 * now = (offset * adj) + xtime_nsec
1392 * Now, even though we're adjusting the clock frequency, we have
1393 * to keep time consistent. In other words, we can't jump back
1394 * in time, and we also want to avoid jumping forward in time.
1396 * So given the same offset value, we need the time to be the same
1397 * both before and after the freq adjustment.
1398 * now = (offset * adj_1) + xtime_nsec_1
1399 * now = (offset * adj_2) + xtime_nsec_2
1401 * (offset * adj_1) + xtime_nsec_1 =
1402 * (offset * adj_2) + xtime_nsec_2
1406 * (offset * adj_1) + xtime_nsec_1 =
1407 * (offset * (adj_1+1)) + xtime_nsec_2
1408 * (offset * adj_1) + xtime_nsec_1 =
1409 * (offset * adj_1) + offset + xtime_nsec_2
1410 * Canceling the sides:
1411 * xtime_nsec_1 = offset + xtime_nsec_2
1413 * xtime_nsec_2 = xtime_nsec_1 - offset
1414 * Which simplfies to:
1415 * xtime_nsec -= offset
1417 * XXX - TODO: Doc ntp_error calculation.
1419 if ((mult_adj
> 0) && (tk
->tkr
.mult
+ mult_adj
< mult_adj
)) {
1420 /* NTP adjustment caused clocksource mult overflow */
1425 tk
->tkr
.mult
+= mult_adj
;
1426 tk
->xtime_interval
+= interval
;
1427 tk
->tkr
.xtime_nsec
-= offset
;
1428 tk
->ntp_error
-= (interval
- offset
) << tk
->ntp_error_shift
;
1432 * Calculate the multiplier adjustment needed to match the frequency
1435 static __always_inline
void timekeeping_freqadjust(struct timekeeper
*tk
,
1438 s64 interval
= tk
->cycle_interval
;
1439 s64 xinterval
= tk
->xtime_interval
;
1444 /* Remove any current error adj from freq calculation */
1445 if (tk
->ntp_err_mult
)
1446 xinterval
-= tk
->cycle_interval
;
1448 tk
->ntp_tick
= ntp_tick_length();
1450 /* Calculate current error per tick */
1451 tick_error
= ntp_tick_length() >> tk
->ntp_error_shift
;
1452 tick_error
-= (xinterval
+ tk
->xtime_remainder
);
1454 /* Don't worry about correcting it if its small */
1455 if (likely((tick_error
>= 0) && (tick_error
<= interval
)))
1458 /* preserve the direction of correction */
1459 negative
= (tick_error
< 0);
1461 /* Sort out the magnitude of the correction */
1462 tick_error
= abs(tick_error
);
1463 for (adj
= 0; tick_error
> interval
; adj
++)
1466 /* scale the corrections */
1467 timekeeping_apply_adjustment(tk
, offset
, negative
, adj
);
1471 * Adjust the timekeeper's multiplier to the correct frequency
1472 * and also to reduce the accumulated error value.
1474 static void timekeeping_adjust(struct timekeeper
*tk
, s64 offset
)
1476 /* Correct for the current frequency error */
1477 timekeeping_freqadjust(tk
, offset
);
1479 /* Next make a small adjustment to fix any cumulative error */
1480 if (!tk
->ntp_err_mult
&& (tk
->ntp_error
> 0)) {
1481 tk
->ntp_err_mult
= 1;
1482 timekeeping_apply_adjustment(tk
, offset
, 0, 0);
1483 } else if (tk
->ntp_err_mult
&& (tk
->ntp_error
<= 0)) {
1484 /* Undo any existing error adjustment */
1485 timekeeping_apply_adjustment(tk
, offset
, 1, 0);
1486 tk
->ntp_err_mult
= 0;
1489 if (unlikely(tk
->tkr
.clock
->maxadj
&&
1490 (abs(tk
->tkr
.mult
- tk
->tkr
.clock
->mult
)
1491 > tk
->tkr
.clock
->maxadj
))) {
1492 printk_once(KERN_WARNING
1493 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1494 tk
->tkr
.clock
->name
, (long)tk
->tkr
.mult
,
1495 (long)tk
->tkr
.clock
->mult
+ tk
->tkr
.clock
->maxadj
);
1499 * It may be possible that when we entered this function, xtime_nsec
1500 * was very small. Further, if we're slightly speeding the clocksource
1501 * in the code above, its possible the required corrective factor to
1502 * xtime_nsec could cause it to underflow.
1504 * Now, since we already accumulated the second, cannot simply roll
1505 * the accumulated second back, since the NTP subsystem has been
1506 * notified via second_overflow. So instead we push xtime_nsec forward
1507 * by the amount we underflowed, and add that amount into the error.
1509 * We'll correct this error next time through this function, when
1510 * xtime_nsec is not as small.
1512 if (unlikely((s64
)tk
->tkr
.xtime_nsec
< 0)) {
1513 s64 neg
= -(s64
)tk
->tkr
.xtime_nsec
;
1514 tk
->tkr
.xtime_nsec
= 0;
1515 tk
->ntp_error
+= neg
<< tk
->ntp_error_shift
;
1520 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1522 * Helper function that accumulates a the nsecs greater then a second
1523 * from the xtime_nsec field to the xtime_secs field.
1524 * It also calls into the NTP code to handle leapsecond processing.
1527 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper
*tk
)
1529 u64 nsecps
= (u64
)NSEC_PER_SEC
<< tk
->tkr
.shift
;
1530 unsigned int clock_set
= 0;
1532 while (tk
->tkr
.xtime_nsec
>= nsecps
) {
1535 tk
->tkr
.xtime_nsec
-= nsecps
;
1538 /* Figure out if its a leap sec and apply if needed */
1539 leap
= second_overflow(tk
->xtime_sec
);
1540 if (unlikely(leap
)) {
1541 struct timespec64 ts
;
1543 tk
->xtime_sec
+= leap
;
1547 tk_set_wall_to_mono(tk
,
1548 timespec64_sub(tk
->wall_to_monotonic
, ts
));
1550 __timekeeping_set_tai_offset(tk
, tk
->tai_offset
- leap
);
1552 clock_set
= TK_CLOCK_WAS_SET
;
1559 * logarithmic_accumulation - shifted accumulation of cycles
1561 * This functions accumulates a shifted interval of cycles into
1562 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1565 * Returns the unconsumed cycles.
1567 static cycle_t
logarithmic_accumulation(struct timekeeper
*tk
, cycle_t offset
,
1569 unsigned int *clock_set
)
1571 cycle_t interval
= tk
->cycle_interval
<< shift
;
1574 /* If the offset is smaller then a shifted interval, do nothing */
1575 if (offset
< interval
)
1578 /* Accumulate one shifted interval */
1580 tk
->tkr
.cycle_last
+= interval
;
1582 tk
->tkr
.xtime_nsec
+= tk
->xtime_interval
<< shift
;
1583 *clock_set
|= accumulate_nsecs_to_secs(tk
);
1585 /* Accumulate raw time */
1586 raw_nsecs
= (u64
)tk
->raw_interval
<< shift
;
1587 raw_nsecs
+= tk
->raw_time
.tv_nsec
;
1588 if (raw_nsecs
>= NSEC_PER_SEC
) {
1589 u64 raw_secs
= raw_nsecs
;
1590 raw_nsecs
= do_div(raw_secs
, NSEC_PER_SEC
);
1591 tk
->raw_time
.tv_sec
+= raw_secs
;
1593 tk
->raw_time
.tv_nsec
= raw_nsecs
;
1595 /* Accumulate error between NTP and clock interval */
1596 tk
->ntp_error
+= tk
->ntp_tick
<< shift
;
1597 tk
->ntp_error
-= (tk
->xtime_interval
+ tk
->xtime_remainder
) <<
1598 (tk
->ntp_error_shift
+ shift
);
1604 * update_wall_time - Uses the current clocksource to increment the wall time
1607 void update_wall_time(void)
1609 struct timekeeper
*real_tk
= &tk_core
.timekeeper
;
1610 struct timekeeper
*tk
= &shadow_timekeeper
;
1612 int shift
= 0, maxshift
;
1613 unsigned int clock_set
= 0;
1614 unsigned long flags
;
1616 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1618 /* Make sure we're fully resumed: */
1619 if (unlikely(timekeeping_suspended
))
1622 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1623 offset
= real_tk
->cycle_interval
;
1625 offset
= clocksource_delta(tk
->tkr
.read(tk
->tkr
.clock
),
1626 tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
1629 /* Check if there's really nothing to do */
1630 if (offset
< real_tk
->cycle_interval
)
1634 * With NO_HZ we may have to accumulate many cycle_intervals
1635 * (think "ticks") worth of time at once. To do this efficiently,
1636 * we calculate the largest doubling multiple of cycle_intervals
1637 * that is smaller than the offset. We then accumulate that
1638 * chunk in one go, and then try to consume the next smaller
1641 shift
= ilog2(offset
) - ilog2(tk
->cycle_interval
);
1642 shift
= max(0, shift
);
1643 /* Bound shift to one less than what overflows tick_length */
1644 maxshift
= (64 - (ilog2(ntp_tick_length())+1)) - 1;
1645 shift
= min(shift
, maxshift
);
1646 while (offset
>= tk
->cycle_interval
) {
1647 offset
= logarithmic_accumulation(tk
, offset
, shift
,
1649 if (offset
< tk
->cycle_interval
<<shift
)
1653 /* correct the clock when NTP error is too big */
1654 timekeeping_adjust(tk
, offset
);
1657 * XXX This can be killed once everyone converts
1658 * to the new update_vsyscall.
1660 old_vsyscall_fixup(tk
);
1663 * Finally, make sure that after the rounding
1664 * xtime_nsec isn't larger than NSEC_PER_SEC
1666 clock_set
|= accumulate_nsecs_to_secs(tk
);
1668 write_seqcount_begin(&tk_core
.seq
);
1670 * Update the real timekeeper.
1672 * We could avoid this memcpy by switching pointers, but that
1673 * requires changes to all other timekeeper usage sites as
1674 * well, i.e. move the timekeeper pointer getter into the
1675 * spinlocked/seqcount protected sections. And we trade this
1676 * memcpy under the tk_core.seq against one before we start
1679 memcpy(real_tk
, tk
, sizeof(*tk
));
1680 timekeeping_update(real_tk
, clock_set
);
1681 write_seqcount_end(&tk_core
.seq
);
1683 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1685 /* Have to call _delayed version, since in irq context*/
1686 clock_was_set_delayed();
1690 * getboottime64 - Return the real time of system boot.
1691 * @ts: pointer to the timespec64 to be set
1693 * Returns the wall-time of boot in a timespec64.
1695 * This is based on the wall_to_monotonic offset and the total suspend
1696 * time. Calls to settimeofday will affect the value returned (which
1697 * basically means that however wrong your real time clock is at boot time,
1698 * you get the right time here).
1700 void getboottime64(struct timespec64
*ts
)
1702 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1703 ktime_t t
= ktime_sub(tk
->offs_real
, tk
->offs_boot
);
1705 *ts
= ktime_to_timespec64(t
);
1707 EXPORT_SYMBOL_GPL(getboottime64
);
1709 unsigned long get_seconds(void)
1711 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1713 return tk
->xtime_sec
;
1715 EXPORT_SYMBOL(get_seconds
);
1717 struct timespec
__current_kernel_time(void)
1719 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1721 return timespec64_to_timespec(tk_xtime(tk
));
1724 struct timespec
current_kernel_time(void)
1726 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1727 struct timespec64 now
;
1731 seq
= read_seqcount_begin(&tk_core
.seq
);
1734 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1736 return timespec64_to_timespec(now
);
1738 EXPORT_SYMBOL(current_kernel_time
);
1740 struct timespec64
get_monotonic_coarse64(void)
1742 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1743 struct timespec64 now
, mono
;
1747 seq
= read_seqcount_begin(&tk_core
.seq
);
1750 mono
= tk
->wall_to_monotonic
;
1751 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1753 set_normalized_timespec64(&now
, now
.tv_sec
+ mono
.tv_sec
,
1754 now
.tv_nsec
+ mono
.tv_nsec
);
1760 * Must hold jiffies_lock
1762 void do_timer(unsigned long ticks
)
1764 jiffies_64
+= ticks
;
1765 calc_global_load(ticks
);
1769 * ktime_get_update_offsets_tick - hrtimer helper
1770 * @offs_real: pointer to storage for monotonic -> realtime offset
1771 * @offs_boot: pointer to storage for monotonic -> boottime offset
1772 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1774 * Returns monotonic time at last tick and various offsets
1776 ktime_t
ktime_get_update_offsets_tick(ktime_t
*offs_real
, ktime_t
*offs_boot
,
1779 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1785 seq
= read_seqcount_begin(&tk_core
.seq
);
1787 base
= tk
->tkr
.base_mono
;
1788 nsecs
= tk
->tkr
.xtime_nsec
>> tk
->tkr
.shift
;
1790 *offs_real
= tk
->offs_real
;
1791 *offs_boot
= tk
->offs_boot
;
1792 *offs_tai
= tk
->offs_tai
;
1793 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1795 return ktime_add_ns(base
, nsecs
);
1798 #ifdef CONFIG_HIGH_RES_TIMERS
1800 * ktime_get_update_offsets_now - hrtimer helper
1801 * @offs_real: pointer to storage for monotonic -> realtime offset
1802 * @offs_boot: pointer to storage for monotonic -> boottime offset
1803 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1805 * Returns current monotonic time and updates the offsets
1806 * Called from hrtimer_interrupt() or retrigger_next_event()
1808 ktime_t
ktime_get_update_offsets_now(ktime_t
*offs_real
, ktime_t
*offs_boot
,
1811 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1817 seq
= read_seqcount_begin(&tk_core
.seq
);
1819 base
= tk
->tkr
.base_mono
;
1820 nsecs
= timekeeping_get_ns(&tk
->tkr
);
1822 *offs_real
= tk
->offs_real
;
1823 *offs_boot
= tk
->offs_boot
;
1824 *offs_tai
= tk
->offs_tai
;
1825 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1827 return ktime_add_ns(base
, nsecs
);
1832 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1834 int do_adjtimex(struct timex
*txc
)
1836 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1837 unsigned long flags
;
1838 struct timespec64 ts
;
1842 /* Validate the data before disabling interrupts */
1843 ret
= ntp_validate_timex(txc
);
1847 if (txc
->modes
& ADJ_SETOFFSET
) {
1848 struct timespec delta
;
1849 delta
.tv_sec
= txc
->time
.tv_sec
;
1850 delta
.tv_nsec
= txc
->time
.tv_usec
;
1851 if (!(txc
->modes
& ADJ_NANO
))
1852 delta
.tv_nsec
*= 1000;
1853 ret
= timekeeping_inject_offset(&delta
);
1858 getnstimeofday64(&ts
);
1860 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1861 write_seqcount_begin(&tk_core
.seq
);
1863 orig_tai
= tai
= tk
->tai_offset
;
1864 ret
= __do_adjtimex(txc
, &ts
, &tai
);
1866 if (tai
!= orig_tai
) {
1867 __timekeeping_set_tai_offset(tk
, tai
);
1868 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1870 write_seqcount_end(&tk_core
.seq
);
1871 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1873 if (tai
!= orig_tai
)
1876 ntp_notify_cmos_timer();
1881 #ifdef CONFIG_NTP_PPS
1883 * hardpps() - Accessor function to NTP __hardpps function
1885 void hardpps(const struct timespec
*phase_ts
, const struct timespec
*raw_ts
)
1887 unsigned long flags
;
1889 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1890 write_seqcount_begin(&tk_core
.seq
);
1892 __hardpps(phase_ts
, raw_ts
);
1894 write_seqcount_end(&tk_core
.seq
);
1895 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1897 EXPORT_SYMBOL(hardpps
);
1901 * xtime_update() - advances the timekeeping infrastructure
1902 * @ticks: number of ticks, that have elapsed since the last call.
1904 * Must be called with interrupts disabled.
1906 void xtime_update(unsigned long ticks
)
1908 write_seqlock(&jiffies_lock
);
1910 write_sequnlock(&jiffies_lock
);