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
;
47 /* flag for if timekeeping is suspended */
48 int __read_mostly timekeeping_suspended
;
50 /* Flag for if there is a persistent clock on this platform */
51 bool __read_mostly persistent_clock_exist
= false;
53 static inline void tk_normalize_xtime(struct timekeeper
*tk
)
55 while (tk
->tkr
.xtime_nsec
>= ((u64
)NSEC_PER_SEC
<< tk
->tkr
.shift
)) {
56 tk
->tkr
.xtime_nsec
-= (u64
)NSEC_PER_SEC
<< tk
->tkr
.shift
;
61 static inline struct timespec64
tk_xtime(struct timekeeper
*tk
)
65 ts
.tv_sec
= tk
->xtime_sec
;
66 ts
.tv_nsec
= (long)(tk
->tkr
.xtime_nsec
>> tk
->tkr
.shift
);
70 static void tk_set_xtime(struct timekeeper
*tk
, const struct timespec64
*ts
)
72 tk
->xtime_sec
= ts
->tv_sec
;
73 tk
->tkr
.xtime_nsec
= (u64
)ts
->tv_nsec
<< tk
->tkr
.shift
;
76 static void tk_xtime_add(struct timekeeper
*tk
, const struct timespec64
*ts
)
78 tk
->xtime_sec
+= ts
->tv_sec
;
79 tk
->tkr
.xtime_nsec
+= (u64
)ts
->tv_nsec
<< tk
->tkr
.shift
;
80 tk_normalize_xtime(tk
);
83 static void tk_set_wall_to_mono(struct timekeeper
*tk
, struct timespec64 wtm
)
85 struct timespec64 tmp
;
88 * Verify consistency of: offset_real = -wall_to_monotonic
89 * before modifying anything
91 set_normalized_timespec64(&tmp
, -tk
->wall_to_monotonic
.tv_sec
,
92 -tk
->wall_to_monotonic
.tv_nsec
);
93 WARN_ON_ONCE(tk
->offs_real
.tv64
!= timespec64_to_ktime(tmp
).tv64
);
94 tk
->wall_to_monotonic
= wtm
;
95 set_normalized_timespec64(&tmp
, -wtm
.tv_sec
, -wtm
.tv_nsec
);
96 tk
->offs_real
= timespec64_to_ktime(tmp
);
97 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tk
->tai_offset
, 0));
100 static inline void tk_update_sleep_time(struct timekeeper
*tk
, ktime_t delta
)
102 tk
->offs_boot
= ktime_add(tk
->offs_boot
, delta
);
106 * tk_setup_internals - Set up internals to use clocksource clock.
108 * @tk: The target timekeeper to setup.
109 * @clock: Pointer to clocksource.
111 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
112 * pair and interval request.
114 * Unless you're the timekeeping code, you should not be using this!
116 static void tk_setup_internals(struct timekeeper
*tk
, struct clocksource
*clock
)
119 u64 tmp
, ntpinterval
;
120 struct clocksource
*old_clock
;
122 old_clock
= tk
->tkr
.clock
;
123 tk
->tkr
.clock
= clock
;
124 tk
->tkr
.read
= clock
->read
;
125 tk
->tkr
.mask
= clock
->mask
;
126 tk
->tkr
.cycle_last
= tk
->tkr
.read(clock
);
128 /* Do the ns -> cycle conversion first, using original mult */
129 tmp
= NTP_INTERVAL_LENGTH
;
130 tmp
<<= clock
->shift
;
132 tmp
+= clock
->mult
/2;
133 do_div(tmp
, clock
->mult
);
137 interval
= (cycle_t
) tmp
;
138 tk
->cycle_interval
= interval
;
140 /* Go back from cycles -> shifted ns */
141 tk
->xtime_interval
= (u64
) interval
* clock
->mult
;
142 tk
->xtime_remainder
= ntpinterval
- tk
->xtime_interval
;
144 ((u64
) interval
* clock
->mult
) >> clock
->shift
;
146 /* if changing clocks, convert xtime_nsec shift units */
148 int shift_change
= clock
->shift
- old_clock
->shift
;
149 if (shift_change
< 0)
150 tk
->tkr
.xtime_nsec
>>= -shift_change
;
152 tk
->tkr
.xtime_nsec
<<= shift_change
;
154 tk
->tkr
.shift
= clock
->shift
;
157 tk
->ntp_error_shift
= NTP_SCALE_SHIFT
- clock
->shift
;
160 * The timekeeper keeps its own mult values for the currently
161 * active clocksource. These value will be adjusted via NTP
162 * to counteract clock drifting.
164 tk
->tkr
.mult
= clock
->mult
;
167 /* Timekeeper helper functions. */
169 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
170 static u32
default_arch_gettimeoffset(void) { return 0; }
171 u32 (*arch_gettimeoffset
)(void) = default_arch_gettimeoffset
;
173 static inline u32
arch_gettimeoffset(void) { return 0; }
176 static inline s64
timekeeping_get_ns(struct timekeeper
*tk
)
178 cycle_t cycle_now
, delta
;
181 /* read clocksource: */
182 cycle_now
= tk
->tkr
.read(tk
->tkr
.clock
);
184 /* calculate the delta since the last update_wall_time: */
185 delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
187 nsec
= delta
* tk
->tkr
.mult
+ tk
->tkr
.xtime_nsec
;
188 nsec
>>= tk
->tkr
.shift
;
190 /* If arch requires, add in get_arch_timeoffset() */
191 return nsec
+ arch_gettimeoffset();
194 static inline s64
timekeeping_get_ns_raw(struct timekeeper
*tk
)
196 struct clocksource
*clock
= tk
->tkr
.clock
;
197 cycle_t cycle_now
, delta
;
200 /* read clocksource: */
201 cycle_now
= tk
->tkr
.read(clock
);
203 /* calculate the delta since the last update_wall_time: */
204 delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
206 /* convert delta to nanoseconds. */
207 nsec
= clocksource_cyc2ns(delta
, clock
->mult
, clock
->shift
);
209 /* If arch requires, add in get_arch_timeoffset() */
210 return nsec
+ arch_gettimeoffset();
213 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
215 static inline void update_vsyscall(struct timekeeper
*tk
)
220 update_vsyscall_old(&xt
, &tk
->wall_to_monotonic
, tk
->tkr
.clock
, tk
->tkr
.mult
,
224 static inline void old_vsyscall_fixup(struct timekeeper
*tk
)
229 * Store only full nanoseconds into xtime_nsec after rounding
230 * it up and add the remainder to the error difference.
231 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
232 * by truncating the remainder in vsyscalls. However, it causes
233 * additional work to be done in timekeeping_adjust(). Once
234 * the vsyscall implementations are converted to use xtime_nsec
235 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
236 * users are removed, this can be killed.
238 remainder
= tk
->tkr
.xtime_nsec
& ((1ULL << tk
->tkr
.shift
) - 1);
239 tk
->tkr
.xtime_nsec
-= remainder
;
240 tk
->tkr
.xtime_nsec
+= 1ULL << tk
->tkr
.shift
;
241 tk
->ntp_error
+= remainder
<< tk
->ntp_error_shift
;
242 tk
->ntp_error
-= (1ULL << tk
->tkr
.shift
) << tk
->ntp_error_shift
;
245 #define old_vsyscall_fixup(tk)
248 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain
);
250 static void update_pvclock_gtod(struct timekeeper
*tk
, bool was_set
)
252 raw_notifier_call_chain(&pvclock_gtod_chain
, was_set
, tk
);
256 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
258 int pvclock_gtod_register_notifier(struct notifier_block
*nb
)
260 struct timekeeper
*tk
= &tk_core
.timekeeper
;
264 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
265 ret
= raw_notifier_chain_register(&pvclock_gtod_chain
, nb
);
266 update_pvclock_gtod(tk
, true);
267 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
271 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier
);
274 * pvclock_gtod_unregister_notifier - unregister a pvclock
275 * timedata update listener
277 int pvclock_gtod_unregister_notifier(struct notifier_block
*nb
)
282 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
283 ret
= raw_notifier_chain_unregister(&pvclock_gtod_chain
, nb
);
284 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
288 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier
);
291 * Update the ktime_t based scalar nsec members of the timekeeper
293 static inline void tk_update_ktime_data(struct timekeeper
*tk
)
298 * The xtime based monotonic readout is:
299 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
300 * The ktime based monotonic readout is:
301 * nsec = base_mono + now();
302 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
304 nsec
= (s64
)(tk
->xtime_sec
+ tk
->wall_to_monotonic
.tv_sec
);
305 nsec
*= NSEC_PER_SEC
;
306 nsec
+= tk
->wall_to_monotonic
.tv_nsec
;
307 tk
->tkr
.base_mono
= ns_to_ktime(nsec
);
309 /* Update the monotonic raw base */
310 tk
->base_raw
= timespec64_to_ktime(tk
->raw_time
);
313 /* must hold timekeeper_lock */
314 static void timekeeping_update(struct timekeeper
*tk
, unsigned int action
)
316 if (action
& TK_CLEAR_NTP
) {
321 update_pvclock_gtod(tk
, action
& TK_CLOCK_WAS_SET
);
323 tk_update_ktime_data(tk
);
325 if (action
& TK_MIRROR
)
326 memcpy(&shadow_timekeeper
, &tk_core
.timekeeper
,
327 sizeof(tk_core
.timekeeper
));
331 * timekeeping_forward_now - update clock to the current time
333 * Forward the current clock to update its state since the last call to
334 * update_wall_time(). This is useful before significant clock changes,
335 * as it avoids having to deal with this time offset explicitly.
337 static void timekeeping_forward_now(struct timekeeper
*tk
)
339 struct clocksource
*clock
= tk
->tkr
.clock
;
340 cycle_t cycle_now
, delta
;
343 cycle_now
= tk
->tkr
.read(clock
);
344 delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
345 tk
->tkr
.cycle_last
= cycle_now
;
347 tk
->tkr
.xtime_nsec
+= delta
* tk
->tkr
.mult
;
349 /* If arch requires, add in get_arch_timeoffset() */
350 tk
->tkr
.xtime_nsec
+= (u64
)arch_gettimeoffset() << tk
->tkr
.shift
;
352 tk_normalize_xtime(tk
);
354 nsec
= clocksource_cyc2ns(delta
, clock
->mult
, clock
->shift
);
355 timespec64_add_ns(&tk
->raw_time
, nsec
);
359 * __getnstimeofday64 - Returns the time of day in a timespec64.
360 * @ts: pointer to the timespec to be set
362 * Updates the time of day in the timespec.
363 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
365 int __getnstimeofday64(struct timespec64
*ts
)
367 struct timekeeper
*tk
= &tk_core
.timekeeper
;
372 seq
= read_seqcount_begin(&tk_core
.seq
);
374 ts
->tv_sec
= tk
->xtime_sec
;
375 nsecs
= timekeeping_get_ns(tk
);
377 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
380 timespec64_add_ns(ts
, nsecs
);
383 * Do not bail out early, in case there were callers still using
384 * the value, even in the face of the WARN_ON.
386 if (unlikely(timekeeping_suspended
))
390 EXPORT_SYMBOL(__getnstimeofday64
);
393 * getnstimeofday64 - Returns the time of day in a timespec64.
394 * @ts: pointer to the timespec to be set
396 * Returns the time of day in a timespec (WARN if suspended).
398 void getnstimeofday64(struct timespec64
*ts
)
400 WARN_ON(__getnstimeofday64(ts
));
402 EXPORT_SYMBOL(getnstimeofday64
);
404 ktime_t
ktime_get(void)
406 struct timekeeper
*tk
= &tk_core
.timekeeper
;
411 WARN_ON(timekeeping_suspended
);
414 seq
= read_seqcount_begin(&tk_core
.seq
);
415 base
= tk
->tkr
.base_mono
;
416 nsecs
= timekeeping_get_ns(tk
);
418 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
420 return ktime_add_ns(base
, nsecs
);
422 EXPORT_SYMBOL_GPL(ktime_get
);
424 static ktime_t
*offsets
[TK_OFFS_MAX
] = {
425 [TK_OFFS_REAL
] = &tk_core
.timekeeper
.offs_real
,
426 [TK_OFFS_BOOT
] = &tk_core
.timekeeper
.offs_boot
,
427 [TK_OFFS_TAI
] = &tk_core
.timekeeper
.offs_tai
,
430 ktime_t
ktime_get_with_offset(enum tk_offsets offs
)
432 struct timekeeper
*tk
= &tk_core
.timekeeper
;
434 ktime_t base
, *offset
= offsets
[offs
];
437 WARN_ON(timekeeping_suspended
);
440 seq
= read_seqcount_begin(&tk_core
.seq
);
441 base
= ktime_add(tk
->tkr
.base_mono
, *offset
);
442 nsecs
= timekeeping_get_ns(tk
);
444 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
446 return ktime_add_ns(base
, nsecs
);
449 EXPORT_SYMBOL_GPL(ktime_get_with_offset
);
452 * ktime_mono_to_any() - convert mononotic time to any other time
453 * @tmono: time to convert.
454 * @offs: which offset to use
456 ktime_t
ktime_mono_to_any(ktime_t tmono
, enum tk_offsets offs
)
458 ktime_t
*offset
= offsets
[offs
];
463 seq
= read_seqcount_begin(&tk_core
.seq
);
464 tconv
= ktime_add(tmono
, *offset
);
465 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
469 EXPORT_SYMBOL_GPL(ktime_mono_to_any
);
472 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
474 ktime_t
ktime_get_raw(void)
476 struct timekeeper
*tk
= &tk_core
.timekeeper
;
482 seq
= read_seqcount_begin(&tk_core
.seq
);
484 nsecs
= timekeeping_get_ns_raw(tk
);
486 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
488 return ktime_add_ns(base
, nsecs
);
490 EXPORT_SYMBOL_GPL(ktime_get_raw
);
493 * ktime_get_ts64 - get the monotonic clock in timespec64 format
494 * @ts: pointer to timespec variable
496 * The function calculates the monotonic clock from the realtime
497 * clock and the wall_to_monotonic offset and stores the result
498 * in normalized timespec format in the variable pointed to by @ts.
500 void ktime_get_ts64(struct timespec64
*ts
)
502 struct timekeeper
*tk
= &tk_core
.timekeeper
;
503 struct timespec64 tomono
;
507 WARN_ON(timekeeping_suspended
);
510 seq
= read_seqcount_begin(&tk_core
.seq
);
511 ts
->tv_sec
= tk
->xtime_sec
;
512 nsec
= timekeeping_get_ns(tk
);
513 tomono
= tk
->wall_to_monotonic
;
515 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
517 ts
->tv_sec
+= tomono
.tv_sec
;
519 timespec64_add_ns(ts
, nsec
+ tomono
.tv_nsec
);
521 EXPORT_SYMBOL_GPL(ktime_get_ts64
);
523 #ifdef CONFIG_NTP_PPS
526 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
527 * @ts_raw: pointer to the timespec to be set to raw monotonic time
528 * @ts_real: pointer to the timespec to be set to the time of day
530 * This function reads both the time of day and raw monotonic time at the
531 * same time atomically and stores the resulting timestamps in timespec
534 void getnstime_raw_and_real(struct timespec
*ts_raw
, struct timespec
*ts_real
)
536 struct timekeeper
*tk
= &tk_core
.timekeeper
;
538 s64 nsecs_raw
, nsecs_real
;
540 WARN_ON_ONCE(timekeeping_suspended
);
543 seq
= read_seqcount_begin(&tk_core
.seq
);
545 *ts_raw
= timespec64_to_timespec(tk
->raw_time
);
546 ts_real
->tv_sec
= tk
->xtime_sec
;
547 ts_real
->tv_nsec
= 0;
549 nsecs_raw
= timekeeping_get_ns_raw(tk
);
550 nsecs_real
= timekeeping_get_ns(tk
);
552 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
554 timespec_add_ns(ts_raw
, nsecs_raw
);
555 timespec_add_ns(ts_real
, nsecs_real
);
557 EXPORT_SYMBOL(getnstime_raw_and_real
);
559 #endif /* CONFIG_NTP_PPS */
562 * do_gettimeofday - Returns the time of day in a timeval
563 * @tv: pointer to the timeval to be set
565 * NOTE: Users should be converted to using getnstimeofday()
567 void do_gettimeofday(struct timeval
*tv
)
569 struct timespec64 now
;
571 getnstimeofday64(&now
);
572 tv
->tv_sec
= now
.tv_sec
;
573 tv
->tv_usec
= now
.tv_nsec
/1000;
575 EXPORT_SYMBOL(do_gettimeofday
);
578 * do_settimeofday - Sets the time of day
579 * @tv: pointer to the timespec variable containing the new time
581 * Sets the time of day to the new time and update NTP and notify hrtimers
583 int do_settimeofday(const struct timespec
*tv
)
585 struct timekeeper
*tk
= &tk_core
.timekeeper
;
586 struct timespec64 ts_delta
, xt
, tmp
;
589 if (!timespec_valid_strict(tv
))
592 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
593 write_seqcount_begin(&tk_core
.seq
);
595 timekeeping_forward_now(tk
);
598 ts_delta
.tv_sec
= tv
->tv_sec
- xt
.tv_sec
;
599 ts_delta
.tv_nsec
= tv
->tv_nsec
- xt
.tv_nsec
;
601 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts_delta
));
603 tmp
= timespec_to_timespec64(*tv
);
604 tk_set_xtime(tk
, &tmp
);
606 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
608 write_seqcount_end(&tk_core
.seq
);
609 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
611 /* signal hrtimers about time change */
616 EXPORT_SYMBOL(do_settimeofday
);
619 * timekeeping_inject_offset - Adds or subtracts from the current time.
620 * @tv: pointer to the timespec variable containing the offset
622 * Adds or subtracts an offset value from the current time.
624 int timekeeping_inject_offset(struct timespec
*ts
)
626 struct timekeeper
*tk
= &tk_core
.timekeeper
;
628 struct timespec64 ts64
, tmp
;
631 if ((unsigned long)ts
->tv_nsec
>= NSEC_PER_SEC
)
634 ts64
= timespec_to_timespec64(*ts
);
636 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
637 write_seqcount_begin(&tk_core
.seq
);
639 timekeeping_forward_now(tk
);
641 /* Make sure the proposed value is valid */
642 tmp
= timespec64_add(tk_xtime(tk
), ts64
);
643 if (!timespec64_valid_strict(&tmp
)) {
648 tk_xtime_add(tk
, &ts64
);
649 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts64
));
651 error
: /* even if we error out, we forwarded the time, so call update */
652 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
654 write_seqcount_end(&tk_core
.seq
);
655 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
657 /* signal hrtimers about time change */
662 EXPORT_SYMBOL(timekeeping_inject_offset
);
666 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
669 s32
timekeeping_get_tai_offset(void)
671 struct timekeeper
*tk
= &tk_core
.timekeeper
;
676 seq
= read_seqcount_begin(&tk_core
.seq
);
677 ret
= tk
->tai_offset
;
678 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
684 * __timekeeping_set_tai_offset - Lock free worker function
687 static void __timekeeping_set_tai_offset(struct timekeeper
*tk
, s32 tai_offset
)
689 tk
->tai_offset
= tai_offset
;
690 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tai_offset
, 0));
694 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
697 void timekeeping_set_tai_offset(s32 tai_offset
)
699 struct timekeeper
*tk
= &tk_core
.timekeeper
;
702 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
703 write_seqcount_begin(&tk_core
.seq
);
704 __timekeeping_set_tai_offset(tk
, tai_offset
);
705 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
706 write_seqcount_end(&tk_core
.seq
);
707 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
712 * change_clocksource - Swaps clocksources if a new one is available
714 * Accumulates current time interval and initializes new clocksource
716 static int change_clocksource(void *data
)
718 struct timekeeper
*tk
= &tk_core
.timekeeper
;
719 struct clocksource
*new, *old
;
722 new = (struct clocksource
*) data
;
724 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
725 write_seqcount_begin(&tk_core
.seq
);
727 timekeeping_forward_now(tk
);
729 * If the cs is in module, get a module reference. Succeeds
730 * for built-in code (owner == NULL) as well.
732 if (try_module_get(new->owner
)) {
733 if (!new->enable
|| new->enable(new) == 0) {
735 tk_setup_internals(tk
, new);
738 module_put(old
->owner
);
740 module_put(new->owner
);
743 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
745 write_seqcount_end(&tk_core
.seq
);
746 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
752 * timekeeping_notify - Install a new clock source
753 * @clock: pointer to the clock source
755 * This function is called from clocksource.c after a new, better clock
756 * source has been registered. The caller holds the clocksource_mutex.
758 int timekeeping_notify(struct clocksource
*clock
)
760 struct timekeeper
*tk
= &tk_core
.timekeeper
;
762 if (tk
->tkr
.clock
== clock
)
764 stop_machine(change_clocksource
, clock
, NULL
);
766 return tk
->tkr
.clock
== clock
? 0 : -1;
770 * getrawmonotonic - Returns the raw monotonic time in a timespec
771 * @ts: pointer to the timespec to be set
773 * Returns the raw monotonic time (completely un-modified by ntp)
775 void getrawmonotonic(struct timespec
*ts
)
777 struct timekeeper
*tk
= &tk_core
.timekeeper
;
778 struct timespec64 ts64
;
783 seq
= read_seqcount_begin(&tk_core
.seq
);
784 nsecs
= timekeeping_get_ns_raw(tk
);
787 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
789 timespec64_add_ns(&ts64
, nsecs
);
790 *ts
= timespec64_to_timespec(ts64
);
792 EXPORT_SYMBOL(getrawmonotonic
);
795 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
797 int timekeeping_valid_for_hres(void)
799 struct timekeeper
*tk
= &tk_core
.timekeeper
;
804 seq
= read_seqcount_begin(&tk_core
.seq
);
806 ret
= tk
->tkr
.clock
->flags
& CLOCK_SOURCE_VALID_FOR_HRES
;
808 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
814 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
816 u64
timekeeping_max_deferment(void)
818 struct timekeeper
*tk
= &tk_core
.timekeeper
;
823 seq
= read_seqcount_begin(&tk_core
.seq
);
825 ret
= tk
->tkr
.clock
->max_idle_ns
;
827 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
833 * read_persistent_clock - Return time from the persistent clock.
835 * Weak dummy function for arches that do not yet support it.
836 * Reads the time from the battery backed persistent clock.
837 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
839 * XXX - Do be sure to remove it once all arches implement it.
841 void __weak
read_persistent_clock(struct timespec
*ts
)
848 * read_boot_clock - Return time of the system start.
850 * Weak dummy function for arches that do not yet support it.
851 * Function to read the exact time the system has been started.
852 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
854 * XXX - Do be sure to remove it once all arches implement it.
856 void __weak
read_boot_clock(struct timespec
*ts
)
863 * timekeeping_init - Initializes the clocksource and common timekeeping values
865 void __init
timekeeping_init(void)
867 struct timekeeper
*tk
= &tk_core
.timekeeper
;
868 struct clocksource
*clock
;
870 struct timespec64 now
, boot
, tmp
;
873 read_persistent_clock(&ts
);
874 now
= timespec_to_timespec64(ts
);
875 if (!timespec64_valid_strict(&now
)) {
876 pr_warn("WARNING: Persistent clock returned invalid value!\n"
877 " Check your CMOS/BIOS settings.\n");
880 } else if (now
.tv_sec
|| now
.tv_nsec
)
881 persistent_clock_exist
= true;
883 read_boot_clock(&ts
);
884 boot
= timespec_to_timespec64(ts
);
885 if (!timespec64_valid_strict(&boot
)) {
886 pr_warn("WARNING: Boot clock returned invalid value!\n"
887 " Check your CMOS/BIOS settings.\n");
892 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
893 write_seqcount_begin(&tk_core
.seq
);
896 clock
= clocksource_default_clock();
898 clock
->enable(clock
);
899 tk_setup_internals(tk
, clock
);
901 tk_set_xtime(tk
, &now
);
902 tk
->raw_time
.tv_sec
= 0;
903 tk
->raw_time
.tv_nsec
= 0;
904 tk
->base_raw
.tv64
= 0;
905 if (boot
.tv_sec
== 0 && boot
.tv_nsec
== 0)
908 set_normalized_timespec64(&tmp
, -boot
.tv_sec
, -boot
.tv_nsec
);
909 tk_set_wall_to_mono(tk
, tmp
);
911 timekeeping_update(tk
, TK_MIRROR
);
913 write_seqcount_end(&tk_core
.seq
);
914 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
917 /* time in seconds when suspend began */
918 static struct timespec64 timekeeping_suspend_time
;
921 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
922 * @delta: pointer to a timespec delta value
924 * Takes a timespec offset measuring a suspend interval and properly
925 * adds the sleep offset to the timekeeping variables.
927 static void __timekeeping_inject_sleeptime(struct timekeeper
*tk
,
928 struct timespec64
*delta
)
930 if (!timespec64_valid_strict(delta
)) {
931 printk_deferred(KERN_WARNING
932 "__timekeeping_inject_sleeptime: Invalid "
933 "sleep delta value!\n");
936 tk_xtime_add(tk
, delta
);
937 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, *delta
));
938 tk_update_sleep_time(tk
, timespec64_to_ktime(*delta
));
939 tk_debug_account_sleep_time(delta
);
943 * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values
944 * @delta: pointer to a timespec delta value
946 * This hook is for architectures that cannot support read_persistent_clock
947 * because their RTC/persistent clock is only accessible when irqs are enabled.
949 * This function should only be called by rtc_resume(), and allows
950 * a suspend offset to be injected into the timekeeping values.
952 void timekeeping_inject_sleeptime(struct timespec
*delta
)
954 struct timekeeper
*tk
= &tk_core
.timekeeper
;
955 struct timespec64 tmp
;
959 * Make sure we don't set the clock twice, as timekeeping_resume()
962 if (has_persistent_clock())
965 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
966 write_seqcount_begin(&tk_core
.seq
);
968 timekeeping_forward_now(tk
);
970 tmp
= timespec_to_timespec64(*delta
);
971 __timekeeping_inject_sleeptime(tk
, &tmp
);
973 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
975 write_seqcount_end(&tk_core
.seq
);
976 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
978 /* signal hrtimers about time change */
983 * timekeeping_resume - Resumes the generic timekeeping subsystem.
985 * This is for the generic clocksource timekeeping.
986 * xtime/wall_to_monotonic/jiffies/etc are
987 * still managed by arch specific suspend/resume code.
989 static void timekeeping_resume(void)
991 struct timekeeper
*tk
= &tk_core
.timekeeper
;
992 struct clocksource
*clock
= tk
->tkr
.clock
;
994 struct timespec64 ts_new
, ts_delta
;
996 cycle_t cycle_now
, cycle_delta
;
997 bool suspendtime_found
= false;
999 read_persistent_clock(&tmp
);
1000 ts_new
= timespec_to_timespec64(tmp
);
1002 clockevents_resume();
1003 clocksource_resume();
1005 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1006 write_seqcount_begin(&tk_core
.seq
);
1009 * After system resumes, we need to calculate the suspended time and
1010 * compensate it for the OS time. There are 3 sources that could be
1011 * used: Nonstop clocksource during suspend, persistent clock and rtc
1014 * One specific platform may have 1 or 2 or all of them, and the
1015 * preference will be:
1016 * suspend-nonstop clocksource -> persistent clock -> rtc
1017 * The less preferred source will only be tried if there is no better
1018 * usable source. The rtc part is handled separately in rtc core code.
1020 cycle_now
= tk
->tkr
.read(clock
);
1021 if ((clock
->flags
& CLOCK_SOURCE_SUSPEND_NONSTOP
) &&
1022 cycle_now
> tk
->tkr
.cycle_last
) {
1023 u64 num
, max
= ULLONG_MAX
;
1024 u32 mult
= clock
->mult
;
1025 u32 shift
= clock
->shift
;
1028 cycle_delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
,
1032 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1033 * suspended time is too long. In that case we need do the
1034 * 64 bits math carefully
1037 if (cycle_delta
> max
) {
1038 num
= div64_u64(cycle_delta
, max
);
1039 nsec
= (((u64
) max
* mult
) >> shift
) * num
;
1040 cycle_delta
-= num
* max
;
1042 nsec
+= ((u64
) cycle_delta
* mult
) >> shift
;
1044 ts_delta
= ns_to_timespec64(nsec
);
1045 suspendtime_found
= true;
1046 } else if (timespec64_compare(&ts_new
, &timekeeping_suspend_time
) > 0) {
1047 ts_delta
= timespec64_sub(ts_new
, timekeeping_suspend_time
);
1048 suspendtime_found
= true;
1051 if (suspendtime_found
)
1052 __timekeeping_inject_sleeptime(tk
, &ts_delta
);
1054 /* Re-base the last cycle value */
1055 tk
->tkr
.cycle_last
= cycle_now
;
1057 timekeeping_suspended
= 0;
1058 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1059 write_seqcount_end(&tk_core
.seq
);
1060 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1062 touch_softlockup_watchdog();
1064 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME
, NULL
);
1066 /* Resume hrtimers */
1070 static int timekeeping_suspend(void)
1072 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1073 unsigned long flags
;
1074 struct timespec64 delta
, delta_delta
;
1075 static struct timespec64 old_delta
;
1076 struct timespec tmp
;
1078 read_persistent_clock(&tmp
);
1079 timekeeping_suspend_time
= timespec_to_timespec64(tmp
);
1082 * On some systems the persistent_clock can not be detected at
1083 * timekeeping_init by its return value, so if we see a valid
1084 * value returned, update the persistent_clock_exists flag.
1086 if (timekeeping_suspend_time
.tv_sec
|| timekeeping_suspend_time
.tv_nsec
)
1087 persistent_clock_exist
= true;
1089 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1090 write_seqcount_begin(&tk_core
.seq
);
1091 timekeeping_forward_now(tk
);
1092 timekeeping_suspended
= 1;
1095 * To avoid drift caused by repeated suspend/resumes,
1096 * which each can add ~1 second drift error,
1097 * try to compensate so the difference in system time
1098 * and persistent_clock time stays close to constant.
1100 delta
= timespec64_sub(tk_xtime(tk
), timekeeping_suspend_time
);
1101 delta_delta
= timespec64_sub(delta
, old_delta
);
1102 if (abs(delta_delta
.tv_sec
) >= 2) {
1104 * if delta_delta is too large, assume time correction
1105 * has occured and set old_delta to the current delta.
1109 /* Otherwise try to adjust old_system to compensate */
1110 timekeeping_suspend_time
=
1111 timespec64_add(timekeeping_suspend_time
, delta_delta
);
1114 timekeeping_update(tk
, TK_MIRROR
);
1115 write_seqcount_end(&tk_core
.seq
);
1116 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1118 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND
, NULL
);
1119 clocksource_suspend();
1120 clockevents_suspend();
1125 /* sysfs resume/suspend bits for timekeeping */
1126 static struct syscore_ops timekeeping_syscore_ops
= {
1127 .resume
= timekeeping_resume
,
1128 .suspend
= timekeeping_suspend
,
1131 static int __init
timekeeping_init_ops(void)
1133 register_syscore_ops(&timekeeping_syscore_ops
);
1137 device_initcall(timekeeping_init_ops
);
1140 * If the error is already larger, we look ahead even further
1141 * to compensate for late or lost adjustments.
1143 static __always_inline
int timekeeping_bigadjust(struct timekeeper
*tk
,
1144 s64 error
, s64
*interval
,
1148 u32 look_ahead
, adj
;
1152 * Use the current error value to determine how much to look ahead.
1153 * The larger the error the slower we adjust for it to avoid problems
1154 * with losing too many ticks, otherwise we would overadjust and
1155 * produce an even larger error. The smaller the adjustment the
1156 * faster we try to adjust for it, as lost ticks can do less harm
1157 * here. This is tuned so that an error of about 1 msec is adjusted
1158 * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
1160 error2
= tk
->ntp_error
>> (NTP_SCALE_SHIFT
+ 22 - 2 * SHIFT_HZ
);
1161 error2
= abs(error2
);
1162 for (look_ahead
= 0; error2
> 0; look_ahead
++)
1166 * Now calculate the error in (1 << look_ahead) ticks, but first
1167 * remove the single look ahead already included in the error.
1169 tick_error
= ntp_tick_length() >> (tk
->ntp_error_shift
+ 1);
1170 tick_error
-= tk
->xtime_interval
>> 1;
1171 error
= ((error
- tick_error
) >> look_ahead
) + tick_error
;
1173 /* Finally calculate the adjustment shift value. */
1178 *interval
= -*interval
;
1182 for (adj
= 0; error
> i
; adj
++)
1191 * Adjust the multiplier to reduce the error value,
1192 * this is optimized for the most common adjustments of -1,0,1,
1193 * for other values we can do a bit more work.
1195 static void timekeeping_adjust(struct timekeeper
*tk
, s64 offset
)
1197 s64 error
, interval
= tk
->cycle_interval
;
1201 * The point of this is to check if the error is greater than half
1204 * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs.
1206 * Note we subtract one in the shift, so that error is really error*2.
1207 * This "saves" dividing(shifting) interval twice, but keeps the
1208 * (error > interval) comparison as still measuring if error is
1209 * larger than half an interval.
1211 * Note: It does not "save" on aggravation when reading the code.
1213 error
= tk
->ntp_error
>> (tk
->ntp_error_shift
- 1);
1214 if (error
> interval
) {
1216 * We now divide error by 4(via shift), which checks if
1217 * the error is greater than twice the interval.
1218 * If it is greater, we need a bigadjust, if its smaller,
1219 * we can adjust by 1.
1222 if (likely(error
<= interval
))
1225 adj
= timekeeping_bigadjust(tk
, error
, &interval
, &offset
);
1227 if (error
< -interval
) {
1228 /* See comment above, this is just switched for the negative */
1230 if (likely(error
>= -interval
)) {
1232 interval
= -interval
;
1235 adj
= timekeeping_bigadjust(tk
, error
, &interval
, &offset
);
1242 if (unlikely(tk
->tkr
.clock
->maxadj
&&
1243 (tk
->tkr
.mult
+ adj
> tk
->tkr
.clock
->mult
+ tk
->tkr
.clock
->maxadj
))) {
1244 printk_deferred_once(KERN_WARNING
1245 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1246 tk
->tkr
.clock
->name
, (long)tk
->tkr
.mult
+ adj
,
1247 (long)tk
->tkr
.clock
->mult
+ tk
->tkr
.clock
->maxadj
);
1250 * So the following can be confusing.
1252 * To keep things simple, lets assume adj == 1 for now.
1254 * When adj != 1, remember that the interval and offset values
1255 * have been appropriately scaled so the math is the same.
1257 * The basic idea here is that we're increasing the multiplier
1258 * by one, this causes the xtime_interval to be incremented by
1259 * one cycle_interval. This is because:
1260 * xtime_interval = cycle_interval * mult
1261 * So if mult is being incremented by one:
1262 * xtime_interval = cycle_interval * (mult + 1)
1264 * xtime_interval = (cycle_interval * mult) + cycle_interval
1265 * Which can be shortened to:
1266 * xtime_interval += cycle_interval
1268 * So offset stores the non-accumulated cycles. Thus the current
1269 * time (in shifted nanoseconds) is:
1270 * now = (offset * adj) + xtime_nsec
1271 * Now, even though we're adjusting the clock frequency, we have
1272 * to keep time consistent. In other words, we can't jump back
1273 * in time, and we also want to avoid jumping forward in time.
1275 * So given the same offset value, we need the time to be the same
1276 * both before and after the freq adjustment.
1277 * now = (offset * adj_1) + xtime_nsec_1
1278 * now = (offset * adj_2) + xtime_nsec_2
1280 * (offset * adj_1) + xtime_nsec_1 =
1281 * (offset * adj_2) + xtime_nsec_2
1285 * (offset * adj_1) + xtime_nsec_1 =
1286 * (offset * (adj_1+1)) + xtime_nsec_2
1287 * (offset * adj_1) + xtime_nsec_1 =
1288 * (offset * adj_1) + offset + xtime_nsec_2
1289 * Canceling the sides:
1290 * xtime_nsec_1 = offset + xtime_nsec_2
1292 * xtime_nsec_2 = xtime_nsec_1 - offset
1293 * Which simplfies to:
1294 * xtime_nsec -= offset
1296 * XXX - TODO: Doc ntp_error calculation.
1298 tk
->tkr
.mult
+= adj
;
1299 tk
->xtime_interval
+= interval
;
1300 tk
->tkr
.xtime_nsec
-= offset
;
1301 tk
->ntp_error
-= (interval
- offset
) << tk
->ntp_error_shift
;
1305 * It may be possible that when we entered this function, xtime_nsec
1306 * was very small. Further, if we're slightly speeding the clocksource
1307 * in the code above, its possible the required corrective factor to
1308 * xtime_nsec could cause it to underflow.
1310 * Now, since we already accumulated the second, cannot simply roll
1311 * the accumulated second back, since the NTP subsystem has been
1312 * notified via second_overflow. So instead we push xtime_nsec forward
1313 * by the amount we underflowed, and add that amount into the error.
1315 * We'll correct this error next time through this function, when
1316 * xtime_nsec is not as small.
1318 if (unlikely((s64
)tk
->tkr
.xtime_nsec
< 0)) {
1319 s64 neg
= -(s64
)tk
->tkr
.xtime_nsec
;
1320 tk
->tkr
.xtime_nsec
= 0;
1321 tk
->ntp_error
+= neg
<< tk
->ntp_error_shift
;
1327 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1329 * Helper function that accumulates a the nsecs greater then a second
1330 * from the xtime_nsec field to the xtime_secs field.
1331 * It also calls into the NTP code to handle leapsecond processing.
1334 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper
*tk
)
1336 u64 nsecps
= (u64
)NSEC_PER_SEC
<< tk
->tkr
.shift
;
1337 unsigned int clock_set
= 0;
1339 while (tk
->tkr
.xtime_nsec
>= nsecps
) {
1342 tk
->tkr
.xtime_nsec
-= nsecps
;
1345 /* Figure out if its a leap sec and apply if needed */
1346 leap
= second_overflow(tk
->xtime_sec
);
1347 if (unlikely(leap
)) {
1348 struct timespec64 ts
;
1350 tk
->xtime_sec
+= leap
;
1354 tk_set_wall_to_mono(tk
,
1355 timespec64_sub(tk
->wall_to_monotonic
, ts
));
1357 __timekeeping_set_tai_offset(tk
, tk
->tai_offset
- leap
);
1359 clock_set
= TK_CLOCK_WAS_SET
;
1366 * logarithmic_accumulation - shifted accumulation of cycles
1368 * This functions accumulates a shifted interval of cycles into
1369 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1372 * Returns the unconsumed cycles.
1374 static cycle_t
logarithmic_accumulation(struct timekeeper
*tk
, cycle_t offset
,
1376 unsigned int *clock_set
)
1378 cycle_t interval
= tk
->cycle_interval
<< shift
;
1381 /* If the offset is smaller then a shifted interval, do nothing */
1382 if (offset
< interval
)
1385 /* Accumulate one shifted interval */
1387 tk
->tkr
.cycle_last
+= interval
;
1389 tk
->tkr
.xtime_nsec
+= tk
->xtime_interval
<< shift
;
1390 *clock_set
|= accumulate_nsecs_to_secs(tk
);
1392 /* Accumulate raw time */
1393 raw_nsecs
= (u64
)tk
->raw_interval
<< shift
;
1394 raw_nsecs
+= tk
->raw_time
.tv_nsec
;
1395 if (raw_nsecs
>= NSEC_PER_SEC
) {
1396 u64 raw_secs
= raw_nsecs
;
1397 raw_nsecs
= do_div(raw_secs
, NSEC_PER_SEC
);
1398 tk
->raw_time
.tv_sec
+= raw_secs
;
1400 tk
->raw_time
.tv_nsec
= raw_nsecs
;
1402 /* Accumulate error between NTP and clock interval */
1403 tk
->ntp_error
+= ntp_tick_length() << shift
;
1404 tk
->ntp_error
-= (tk
->xtime_interval
+ tk
->xtime_remainder
) <<
1405 (tk
->ntp_error_shift
+ shift
);
1411 * update_wall_time - Uses the current clocksource to increment the wall time
1414 void update_wall_time(void)
1416 struct timekeeper
*real_tk
= &tk_core
.timekeeper
;
1417 struct timekeeper
*tk
= &shadow_timekeeper
;
1419 int shift
= 0, maxshift
;
1420 unsigned int clock_set
= 0;
1421 unsigned long flags
;
1423 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1425 /* Make sure we're fully resumed: */
1426 if (unlikely(timekeeping_suspended
))
1429 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1430 offset
= real_tk
->cycle_interval
;
1432 offset
= clocksource_delta(tk
->tkr
.read(tk
->tkr
.clock
),
1433 tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
1436 /* Check if there's really nothing to do */
1437 if (offset
< real_tk
->cycle_interval
)
1441 * With NO_HZ we may have to accumulate many cycle_intervals
1442 * (think "ticks") worth of time at once. To do this efficiently,
1443 * we calculate the largest doubling multiple of cycle_intervals
1444 * that is smaller than the offset. We then accumulate that
1445 * chunk in one go, and then try to consume the next smaller
1448 shift
= ilog2(offset
) - ilog2(tk
->cycle_interval
);
1449 shift
= max(0, shift
);
1450 /* Bound shift to one less than what overflows tick_length */
1451 maxshift
= (64 - (ilog2(ntp_tick_length())+1)) - 1;
1452 shift
= min(shift
, maxshift
);
1453 while (offset
>= tk
->cycle_interval
) {
1454 offset
= logarithmic_accumulation(tk
, offset
, shift
,
1456 if (offset
< tk
->cycle_interval
<<shift
)
1460 /* correct the clock when NTP error is too big */
1461 timekeeping_adjust(tk
, offset
);
1464 * XXX This can be killed once everyone converts
1465 * to the new update_vsyscall.
1467 old_vsyscall_fixup(tk
);
1470 * Finally, make sure that after the rounding
1471 * xtime_nsec isn't larger than NSEC_PER_SEC
1473 clock_set
|= accumulate_nsecs_to_secs(tk
);
1475 write_seqcount_begin(&tk_core
.seq
);
1477 * Update the real timekeeper.
1479 * We could avoid this memcpy by switching pointers, but that
1480 * requires changes to all other timekeeper usage sites as
1481 * well, i.e. move the timekeeper pointer getter into the
1482 * spinlocked/seqcount protected sections. And we trade this
1483 * memcpy under the tk_core.seq against one before we start
1486 memcpy(real_tk
, tk
, sizeof(*tk
));
1487 timekeeping_update(real_tk
, clock_set
);
1488 write_seqcount_end(&tk_core
.seq
);
1490 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1492 /* Have to call _delayed version, since in irq context*/
1493 clock_was_set_delayed();
1497 * getboottime - Return the real time of system boot.
1498 * @ts: pointer to the timespec to be set
1500 * Returns the wall-time of boot in a timespec.
1502 * This is based on the wall_to_monotonic offset and the total suspend
1503 * time. Calls to settimeofday will affect the value returned (which
1504 * basically means that however wrong your real time clock is at boot time,
1505 * you get the right time here).
1507 void getboottime(struct timespec
*ts
)
1509 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1510 ktime_t t
= ktime_sub(tk
->offs_real
, tk
->offs_boot
);
1512 *ts
= ktime_to_timespec(t
);
1514 EXPORT_SYMBOL_GPL(getboottime
);
1516 unsigned long get_seconds(void)
1518 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1520 return tk
->xtime_sec
;
1522 EXPORT_SYMBOL(get_seconds
);
1524 struct timespec
__current_kernel_time(void)
1526 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1528 return timespec64_to_timespec(tk_xtime(tk
));
1531 struct timespec
current_kernel_time(void)
1533 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1534 struct timespec64 now
;
1538 seq
= read_seqcount_begin(&tk_core
.seq
);
1541 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1543 return timespec64_to_timespec(now
);
1545 EXPORT_SYMBOL(current_kernel_time
);
1547 struct timespec
get_monotonic_coarse(void)
1549 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1550 struct timespec64 now
, mono
;
1554 seq
= read_seqcount_begin(&tk_core
.seq
);
1557 mono
= tk
->wall_to_monotonic
;
1558 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1560 set_normalized_timespec64(&now
, now
.tv_sec
+ mono
.tv_sec
,
1561 now
.tv_nsec
+ mono
.tv_nsec
);
1563 return timespec64_to_timespec(now
);
1567 * Must hold jiffies_lock
1569 void do_timer(unsigned long ticks
)
1571 jiffies_64
+= ticks
;
1572 calc_global_load(ticks
);
1576 * ktime_get_update_offsets_tick - hrtimer helper
1577 * @offs_real: pointer to storage for monotonic -> realtime offset
1578 * @offs_boot: pointer to storage for monotonic -> boottime offset
1579 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1581 * Returns monotonic time at last tick and various offsets
1583 ktime_t
ktime_get_update_offsets_tick(ktime_t
*offs_real
, ktime_t
*offs_boot
,
1586 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1592 seq
= read_seqcount_begin(&tk_core
.seq
);
1594 base
= tk
->tkr
.base_mono
;
1595 nsecs
= tk
->tkr
.xtime_nsec
>> tk
->tkr
.shift
;
1597 *offs_real
= tk
->offs_real
;
1598 *offs_boot
= tk
->offs_boot
;
1599 *offs_tai
= tk
->offs_tai
;
1600 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1602 return ktime_add_ns(base
, nsecs
);
1605 #ifdef CONFIG_HIGH_RES_TIMERS
1607 * ktime_get_update_offsets_now - hrtimer helper
1608 * @offs_real: pointer to storage for monotonic -> realtime offset
1609 * @offs_boot: pointer to storage for monotonic -> boottime offset
1610 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1612 * Returns current monotonic time and updates the offsets
1613 * Called from hrtimer_interrupt() or retrigger_next_event()
1615 ktime_t
ktime_get_update_offsets_now(ktime_t
*offs_real
, ktime_t
*offs_boot
,
1618 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1624 seq
= read_seqcount_begin(&tk_core
.seq
);
1626 base
= tk
->tkr
.base_mono
;
1627 nsecs
= timekeeping_get_ns(tk
);
1629 *offs_real
= tk
->offs_real
;
1630 *offs_boot
= tk
->offs_boot
;
1631 *offs_tai
= tk
->offs_tai
;
1632 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1634 return ktime_add_ns(base
, nsecs
);
1639 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1641 int do_adjtimex(struct timex
*txc
)
1643 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1644 unsigned long flags
;
1645 struct timespec64 ts
;
1649 /* Validate the data before disabling interrupts */
1650 ret
= ntp_validate_timex(txc
);
1654 if (txc
->modes
& ADJ_SETOFFSET
) {
1655 struct timespec delta
;
1656 delta
.tv_sec
= txc
->time
.tv_sec
;
1657 delta
.tv_nsec
= txc
->time
.tv_usec
;
1658 if (!(txc
->modes
& ADJ_NANO
))
1659 delta
.tv_nsec
*= 1000;
1660 ret
= timekeeping_inject_offset(&delta
);
1665 getnstimeofday64(&ts
);
1667 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1668 write_seqcount_begin(&tk_core
.seq
);
1670 orig_tai
= tai
= tk
->tai_offset
;
1671 ret
= __do_adjtimex(txc
, &ts
, &tai
);
1673 if (tai
!= orig_tai
) {
1674 __timekeeping_set_tai_offset(tk
, tai
);
1675 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1677 write_seqcount_end(&tk_core
.seq
);
1678 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1680 if (tai
!= orig_tai
)
1683 ntp_notify_cmos_timer();
1688 #ifdef CONFIG_NTP_PPS
1690 * hardpps() - Accessor function to NTP __hardpps function
1692 void hardpps(const struct timespec
*phase_ts
, const struct timespec
*raw_ts
)
1694 unsigned long flags
;
1696 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1697 write_seqcount_begin(&tk_core
.seq
);
1699 __hardpps(phase_ts
, raw_ts
);
1701 write_seqcount_end(&tk_core
.seq
);
1702 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1704 EXPORT_SYMBOL(hardpps
);
1708 * xtime_update() - advances the timekeeping infrastructure
1709 * @ticks: number of ticks, that have elapsed since the last call.
1711 * Must be called with interrupts disabled.
1713 void xtime_update(unsigned long ticks
)
1715 write_seqlock(&jiffies_lock
);
1717 write_sequnlock(&jiffies_lock
);