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1 | /* |
2 | * linux/kernel/time/timekeeping.c |
3 | * |
4 | * Kernel timekeeping code and accessor functions |
5 | * |
6 | * This code was moved from linux/kernel/timer.c. |
7 | * Please see that file for copyright and history logs. |
8 | * |
9 | */ |
10 | |
11 | #include <linux/module.h> |
12 | #include <linux/interrupt.h> |
13 | #include <linux/percpu.h> |
14 | #include <linux/init.h> |
15 | #include <linux/mm.h> |
16 | #include <linux/sched.h> |
17 | #include <linux/syscore_ops.h> |
18 | #include <linux/clocksource.h> |
19 | #include <linux/jiffies.h> |
20 | #include <linux/time.h> |
21 | #include <linux/tick.h> |
22 | #include <linux/stop_machine.h> |
23 | |
24 | /* Structure holding internal timekeeping values. */ |
25 | struct timekeeper { |
26 | /* Current clocksource used for timekeeping. */ |
27 | struct clocksource *clock; |
28 | /* NTP adjusted clock multiplier */ |
29 | u32 mult; |
30 | /* The shift value of the current clocksource. */ |
31 | int shift; |
32 | |
33 | /* Number of clock cycles in one NTP interval. */ |
34 | cycle_t cycle_interval; |
35 | /* Number of clock shifted nano seconds in one NTP interval. */ |
36 | u64 xtime_interval; |
37 | /* shifted nano seconds left over when rounding cycle_interval */ |
38 | s64 xtime_remainder; |
39 | /* Raw nano seconds accumulated per NTP interval. */ |
40 | u32 raw_interval; |
41 | |
42 | /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */ |
43 | u64 xtime_nsec; |
44 | /* Difference between accumulated time and NTP time in ntp |
45 | * shifted nano seconds. */ |
46 | s64 ntp_error; |
47 | /* Shift conversion between clock shifted nano seconds and |
48 | * ntp shifted nano seconds. */ |
49 | int ntp_error_shift; |
50 | |
51 | /* The current time */ |
52 | struct timespec xtime; |
53 | /* |
54 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected |
55 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged |
56 | * at zero at system boot time, so wall_to_monotonic will be negative, |
57 | * however, we will ALWAYS keep the tv_nsec part positive so we can use |
58 | * the usual normalization. |
59 | * |
60 | * wall_to_monotonic is moved after resume from suspend for the |
61 | * monotonic time not to jump. We need to add total_sleep_time to |
62 | * wall_to_monotonic to get the real boot based time offset. |
63 | * |
64 | * - wall_to_monotonic is no longer the boot time, getboottime must be |
65 | * used instead. |
66 | */ |
67 | struct timespec wall_to_monotonic; |
68 | /* time spent in suspend */ |
69 | struct timespec total_sleep_time; |
70 | /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */ |
71 | struct timespec raw_time; |
72 | |
73 | /* Offset clock monotonic -> clock realtime */ |
74 | ktime_t offs_real; |
75 | |
76 | /* Offset clock monotonic -> clock boottime */ |
77 | ktime_t offs_boot; |
78 | |
79 | /* Seqlock for all timekeeper values */ |
80 | seqlock_t lock; |
81 | }; |
82 | |
83 | static struct timekeeper timekeeper; |
84 | |
85 | /* |
86 | * This read-write spinlock protects us from races in SMP while |
87 | * playing with xtime. |
88 | */ |
89 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); |
90 | |
91 | |
92 | /* flag for if timekeeping is suspended */ |
93 | int __read_mostly timekeeping_suspended; |
94 | |
95 | |
96 | |
97 | /** |
98 | * timekeeper_setup_internals - Set up internals to use clocksource clock. |
99 | * |
100 | * @clock: Pointer to clocksource. |
101 | * |
102 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment |
103 | * pair and interval request. |
104 | * |
105 | * Unless you're the timekeeping code, you should not be using this! |
106 | */ |
107 | static void timekeeper_setup_internals(struct clocksource *clock) |
108 | { |
109 | cycle_t interval; |
110 | u64 tmp, ntpinterval; |
111 | |
112 | timekeeper.clock = clock; |
113 | clock->cycle_last = clock->read(clock); |
114 | |
115 | /* Do the ns -> cycle conversion first, using original mult */ |
116 | tmp = NTP_INTERVAL_LENGTH; |
117 | tmp <<= clock->shift; |
118 | ntpinterval = tmp; |
119 | tmp += clock->mult/2; |
120 | do_div(tmp, clock->mult); |
121 | if (tmp == 0) |
122 | tmp = 1; |
123 | |
124 | interval = (cycle_t) tmp; |
125 | timekeeper.cycle_interval = interval; |
126 | |
127 | /* Go back from cycles -> shifted ns */ |
128 | timekeeper.xtime_interval = (u64) interval * clock->mult; |
129 | timekeeper.xtime_remainder = ntpinterval - timekeeper.xtime_interval; |
130 | timekeeper.raw_interval = |
131 | ((u64) interval * clock->mult) >> clock->shift; |
132 | |
133 | timekeeper.xtime_nsec = 0; |
134 | timekeeper.shift = clock->shift; |
135 | |
136 | timekeeper.ntp_error = 0; |
137 | timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
138 | |
139 | /* |
140 | * The timekeeper keeps its own mult values for the currently |
141 | * active clocksource. These value will be adjusted via NTP |
142 | * to counteract clock drifting. |
143 | */ |
144 | timekeeper.mult = clock->mult; |
145 | } |
146 | |
147 | /* Timekeeper helper functions. */ |
148 | static inline s64 timekeeping_get_ns(void) |
149 | { |
150 | cycle_t cycle_now, cycle_delta; |
151 | struct clocksource *clock; |
152 | |
153 | /* read clocksource: */ |
154 | clock = timekeeper.clock; |
155 | cycle_now = clock->read(clock); |
156 | |
157 | /* calculate the delta since the last update_wall_time: */ |
158 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
159 | |
160 | /* return delta convert to nanoseconds using ntp adjusted mult. */ |
161 | return clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
162 | timekeeper.shift); |
163 | } |
164 | |
165 | static inline s64 timekeeping_get_ns_raw(void) |
166 | { |
167 | cycle_t cycle_now, cycle_delta; |
168 | struct clocksource *clock; |
169 | |
170 | /* read clocksource: */ |
171 | clock = timekeeper.clock; |
172 | cycle_now = clock->read(clock); |
173 | |
174 | /* calculate the delta since the last update_wall_time: */ |
175 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
176 | |
177 | /* return delta convert to nanoseconds. */ |
178 | return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
179 | } |
180 | |
181 | static void update_rt_offset(void) |
182 | { |
183 | struct timespec tmp, *wtm = &timekeeper.wall_to_monotonic; |
184 | |
185 | set_normalized_timespec(&tmp, -wtm->tv_sec, -wtm->tv_nsec); |
186 | timekeeper.offs_real = timespec_to_ktime(tmp); |
187 | } |
188 | |
189 | /* must hold write on timekeeper.lock */ |
190 | static void timekeeping_update(bool clearntp) |
191 | { |
192 | if (clearntp) { |
193 | timekeeper.ntp_error = 0; |
194 | ntp_clear(); |
195 | } |
196 | update_rt_offset(); |
197 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
198 | timekeeper.clock, timekeeper.mult); |
199 | } |
200 | |
201 | |
202 | /** |
203 | * timekeeping_forward_now - update clock to the current time |
204 | * |
205 | * Forward the current clock to update its state since the last call to |
206 | * update_wall_time(). This is useful before significant clock changes, |
207 | * as it avoids having to deal with this time offset explicitly. |
208 | */ |
209 | static void timekeeping_forward_now(void) |
210 | { |
211 | cycle_t cycle_now, cycle_delta; |
212 | struct clocksource *clock; |
213 | s64 nsec; |
214 | |
215 | clock = timekeeper.clock; |
216 | cycle_now = clock->read(clock); |
217 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
218 | clock->cycle_last = cycle_now; |
219 | |
220 | nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
221 | timekeeper.shift); |
222 | |
223 | /* If arch requires, add in gettimeoffset() */ |
224 | nsec += arch_gettimeoffset(); |
225 | |
226 | timespec_add_ns(&timekeeper.xtime, nsec); |
227 | |
228 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
229 | timespec_add_ns(&timekeeper.raw_time, nsec); |
230 | } |
231 | |
232 | /** |
233 | * getnstimeofday - Returns the time of day in a timespec |
234 | * @ts: pointer to the timespec to be set |
235 | * |
236 | * Returns the time of day in a timespec. |
237 | */ |
238 | void getnstimeofday(struct timespec *ts) |
239 | { |
240 | unsigned long seq; |
241 | s64 nsecs; |
242 | |
243 | WARN_ON(timekeeping_suspended); |
244 | |
245 | do { |
246 | seq = read_seqbegin(&timekeeper.lock); |
247 | |
248 | *ts = timekeeper.xtime; |
249 | nsecs = timekeeping_get_ns(); |
250 | |
251 | /* If arch requires, add in gettimeoffset() */ |
252 | nsecs += arch_gettimeoffset(); |
253 | |
254 | } while (read_seqretry(&timekeeper.lock, seq)); |
255 | |
256 | timespec_add_ns(ts, nsecs); |
257 | } |
258 | EXPORT_SYMBOL(getnstimeofday); |
259 | |
260 | ktime_t ktime_get(void) |
261 | { |
262 | unsigned int seq; |
263 | s64 secs, nsecs; |
264 | |
265 | WARN_ON(timekeeping_suspended); |
266 | |
267 | do { |
268 | seq = read_seqbegin(&timekeeper.lock); |
269 | secs = timekeeper.xtime.tv_sec + |
270 | timekeeper.wall_to_monotonic.tv_sec; |
271 | nsecs = timekeeper.xtime.tv_nsec + |
272 | timekeeper.wall_to_monotonic.tv_nsec; |
273 | nsecs += timekeeping_get_ns(); |
274 | /* If arch requires, add in gettimeoffset() */ |
275 | nsecs += arch_gettimeoffset(); |
276 | |
277 | } while (read_seqretry(&timekeeper.lock, seq)); |
278 | /* |
279 | * Use ktime_set/ktime_add_ns to create a proper ktime on |
280 | * 32-bit architectures without CONFIG_KTIME_SCALAR. |
281 | */ |
282 | return ktime_add_ns(ktime_set(secs, 0), nsecs); |
283 | } |
284 | EXPORT_SYMBOL_GPL(ktime_get); |
285 | |
286 | /** |
287 | * ktime_get_ts - get the monotonic clock in timespec format |
288 | * @ts: pointer to timespec variable |
289 | * |
290 | * The function calculates the monotonic clock from the realtime |
291 | * clock and the wall_to_monotonic offset and stores the result |
292 | * in normalized timespec format in the variable pointed to by @ts. |
293 | */ |
294 | void ktime_get_ts(struct timespec *ts) |
295 | { |
296 | struct timespec tomono; |
297 | unsigned int seq; |
298 | s64 nsecs; |
299 | |
300 | WARN_ON(timekeeping_suspended); |
301 | |
302 | do { |
303 | seq = read_seqbegin(&timekeeper.lock); |
304 | *ts = timekeeper.xtime; |
305 | tomono = timekeeper.wall_to_monotonic; |
306 | nsecs = timekeeping_get_ns(); |
307 | /* If arch requires, add in gettimeoffset() */ |
308 | nsecs += arch_gettimeoffset(); |
309 | |
310 | } while (read_seqretry(&timekeeper.lock, seq)); |
311 | |
312 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, |
313 | ts->tv_nsec + tomono.tv_nsec + nsecs); |
314 | } |
315 | EXPORT_SYMBOL_GPL(ktime_get_ts); |
316 | |
317 | #ifdef CONFIG_NTP_PPS |
318 | |
319 | /** |
320 | * getnstime_raw_and_real - get day and raw monotonic time in timespec format |
321 | * @ts_raw: pointer to the timespec to be set to raw monotonic time |
322 | * @ts_real: pointer to the timespec to be set to the time of day |
323 | * |
324 | * This function reads both the time of day and raw monotonic time at the |
325 | * same time atomically and stores the resulting timestamps in timespec |
326 | * format. |
327 | */ |
328 | void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) |
329 | { |
330 | unsigned long seq; |
331 | s64 nsecs_raw, nsecs_real; |
332 | |
333 | WARN_ON_ONCE(timekeeping_suspended); |
334 | |
335 | do { |
336 | u32 arch_offset; |
337 | |
338 | seq = read_seqbegin(&timekeeper.lock); |
339 | |
340 | *ts_raw = timekeeper.raw_time; |
341 | *ts_real = timekeeper.xtime; |
342 | |
343 | nsecs_raw = timekeeping_get_ns_raw(); |
344 | nsecs_real = timekeeping_get_ns(); |
345 | |
346 | /* If arch requires, add in gettimeoffset() */ |
347 | arch_offset = arch_gettimeoffset(); |
348 | nsecs_raw += arch_offset; |
349 | nsecs_real += arch_offset; |
350 | |
351 | } while (read_seqretry(&timekeeper.lock, seq)); |
352 | |
353 | timespec_add_ns(ts_raw, nsecs_raw); |
354 | timespec_add_ns(ts_real, nsecs_real); |
355 | } |
356 | EXPORT_SYMBOL(getnstime_raw_and_real); |
357 | |
358 | #endif /* CONFIG_NTP_PPS */ |
359 | |
360 | /** |
361 | * do_gettimeofday - Returns the time of day in a timeval |
362 | * @tv: pointer to the timeval to be set |
363 | * |
364 | * NOTE: Users should be converted to using getnstimeofday() |
365 | */ |
366 | void do_gettimeofday(struct timeval *tv) |
367 | { |
368 | struct timespec now; |
369 | |
370 | getnstimeofday(&now); |
371 | tv->tv_sec = now.tv_sec; |
372 | tv->tv_usec = now.tv_nsec/1000; |
373 | } |
374 | EXPORT_SYMBOL(do_gettimeofday); |
375 | |
376 | /** |
377 | * do_settimeofday - Sets the time of day |
378 | * @tv: pointer to the timespec variable containing the new time |
379 | * |
380 | * Sets the time of day to the new time and update NTP and notify hrtimers |
381 | */ |
382 | int do_settimeofday(const struct timespec *tv) |
383 | { |
384 | struct timespec ts_delta; |
385 | unsigned long flags; |
386 | |
387 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
388 | return -EINVAL; |
389 | |
390 | write_seqlock_irqsave(&timekeeper.lock, flags); |
391 | |
392 | timekeeping_forward_now(); |
393 | |
394 | ts_delta.tv_sec = tv->tv_sec - timekeeper.xtime.tv_sec; |
395 | ts_delta.tv_nsec = tv->tv_nsec - timekeeper.xtime.tv_nsec; |
396 | timekeeper.wall_to_monotonic = |
397 | timespec_sub(timekeeper.wall_to_monotonic, ts_delta); |
398 | |
399 | timekeeper.xtime = *tv; |
400 | timekeeping_update(true); |
401 | |
402 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
403 | |
404 | /* signal hrtimers about time change */ |
405 | clock_was_set(); |
406 | |
407 | return 0; |
408 | } |
409 | EXPORT_SYMBOL(do_settimeofday); |
410 | |
411 | |
412 | /** |
413 | * timekeeping_inject_offset - Adds or subtracts from the current time. |
414 | * @tv: pointer to the timespec variable containing the offset |
415 | * |
416 | * Adds or subtracts an offset value from the current time. |
417 | */ |
418 | int timekeeping_inject_offset(struct timespec *ts) |
419 | { |
420 | unsigned long flags; |
421 | |
422 | if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) |
423 | return -EINVAL; |
424 | |
425 | write_seqlock_irqsave(&timekeeper.lock, flags); |
426 | |
427 | timekeeping_forward_now(); |
428 | |
429 | timekeeper.xtime = timespec_add(timekeeper.xtime, *ts); |
430 | timekeeper.wall_to_monotonic = |
431 | timespec_sub(timekeeper.wall_to_monotonic, *ts); |
432 | |
433 | timekeeping_update(true); |
434 | |
435 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
436 | |
437 | /* signal hrtimers about time change */ |
438 | clock_was_set(); |
439 | |
440 | return 0; |
441 | } |
442 | EXPORT_SYMBOL(timekeeping_inject_offset); |
443 | |
444 | /** |
445 | * change_clocksource - Swaps clocksources if a new one is available |
446 | * |
447 | * Accumulates current time interval and initializes new clocksource |
448 | */ |
449 | static int change_clocksource(void *data) |
450 | { |
451 | struct clocksource *new, *old; |
452 | unsigned long flags; |
453 | |
454 | new = (struct clocksource *) data; |
455 | |
456 | write_seqlock_irqsave(&timekeeper.lock, flags); |
457 | |
458 | timekeeping_forward_now(); |
459 | if (!new->enable || new->enable(new) == 0) { |
460 | old = timekeeper.clock; |
461 | timekeeper_setup_internals(new); |
462 | if (old->disable) |
463 | old->disable(old); |
464 | } |
465 | timekeeping_update(true); |
466 | |
467 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
468 | |
469 | return 0; |
470 | } |
471 | |
472 | /** |
473 | * timekeeping_notify - Install a new clock source |
474 | * @clock: pointer to the clock source |
475 | * |
476 | * This function is called from clocksource.c after a new, better clock |
477 | * source has been registered. The caller holds the clocksource_mutex. |
478 | */ |
479 | void timekeeping_notify(struct clocksource *clock) |
480 | { |
481 | if (timekeeper.clock == clock) |
482 | return; |
483 | stop_machine(change_clocksource, clock, NULL); |
484 | tick_clock_notify(); |
485 | } |
486 | |
487 | /** |
488 | * ktime_get_real - get the real (wall-) time in ktime_t format |
489 | * |
490 | * returns the time in ktime_t format |
491 | */ |
492 | ktime_t ktime_get_real(void) |
493 | { |
494 | struct timespec now; |
495 | |
496 | getnstimeofday(&now); |
497 | |
498 | return timespec_to_ktime(now); |
499 | } |
500 | EXPORT_SYMBOL_GPL(ktime_get_real); |
501 | |
502 | /** |
503 | * getrawmonotonic - Returns the raw monotonic time in a timespec |
504 | * @ts: pointer to the timespec to be set |
505 | * |
506 | * Returns the raw monotonic time (completely un-modified by ntp) |
507 | */ |
508 | void getrawmonotonic(struct timespec *ts) |
509 | { |
510 | unsigned long seq; |
511 | s64 nsecs; |
512 | |
513 | do { |
514 | seq = read_seqbegin(&timekeeper.lock); |
515 | nsecs = timekeeping_get_ns_raw(); |
516 | *ts = timekeeper.raw_time; |
517 | |
518 | } while (read_seqretry(&timekeeper.lock, seq)); |
519 | |
520 | timespec_add_ns(ts, nsecs); |
521 | } |
522 | EXPORT_SYMBOL(getrawmonotonic); |
523 | |
524 | |
525 | /** |
526 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
527 | */ |
528 | int timekeeping_valid_for_hres(void) |
529 | { |
530 | unsigned long seq; |
531 | int ret; |
532 | |
533 | do { |
534 | seq = read_seqbegin(&timekeeper.lock); |
535 | |
536 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
537 | |
538 | } while (read_seqretry(&timekeeper.lock, seq)); |
539 | |
540 | return ret; |
541 | } |
542 | |
543 | /** |
544 | * timekeeping_max_deferment - Returns max time the clocksource can be deferred |
545 | */ |
546 | u64 timekeeping_max_deferment(void) |
547 | { |
548 | unsigned long seq; |
549 | u64 ret; |
550 | do { |
551 | seq = read_seqbegin(&timekeeper.lock); |
552 | |
553 | ret = timekeeper.clock->max_idle_ns; |
554 | |
555 | } while (read_seqretry(&timekeeper.lock, seq)); |
556 | |
557 | return ret; |
558 | } |
559 | |
560 | /** |
561 | * read_persistent_clock - Return time from the persistent clock. |
562 | * |
563 | * Weak dummy function for arches that do not yet support it. |
564 | * Reads the time from the battery backed persistent clock. |
565 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. |
566 | * |
567 | * XXX - Do be sure to remove it once all arches implement it. |
568 | */ |
569 | void __attribute__((weak)) read_persistent_clock(struct timespec *ts) |
570 | { |
571 | ts->tv_sec = 0; |
572 | ts->tv_nsec = 0; |
573 | } |
574 | |
575 | /** |
576 | * read_boot_clock - Return time of the system start. |
577 | * |
578 | * Weak dummy function for arches that do not yet support it. |
579 | * Function to read the exact time the system has been started. |
580 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. |
581 | * |
582 | * XXX - Do be sure to remove it once all arches implement it. |
583 | */ |
584 | void __attribute__((weak)) read_boot_clock(struct timespec *ts) |
585 | { |
586 | ts->tv_sec = 0; |
587 | ts->tv_nsec = 0; |
588 | } |
589 | |
590 | /* |
591 | * timekeeping_init - Initializes the clocksource and common timekeeping values |
592 | */ |
593 | void __init timekeeping_init(void) |
594 | { |
595 | struct clocksource *clock; |
596 | unsigned long flags; |
597 | struct timespec now, boot; |
598 | |
599 | read_persistent_clock(&now); |
600 | read_boot_clock(&boot); |
601 | |
602 | seqlock_init(&timekeeper.lock); |
603 | |
604 | ntp_init(); |
605 | |
606 | write_seqlock_irqsave(&timekeeper.lock, flags); |
607 | clock = clocksource_default_clock(); |
608 | if (clock->enable) |
609 | clock->enable(clock); |
610 | timekeeper_setup_internals(clock); |
611 | |
612 | timekeeper.xtime.tv_sec = now.tv_sec; |
613 | timekeeper.xtime.tv_nsec = now.tv_nsec; |
614 | timekeeper.raw_time.tv_sec = 0; |
615 | timekeeper.raw_time.tv_nsec = 0; |
616 | if (boot.tv_sec == 0 && boot.tv_nsec == 0) { |
617 | boot.tv_sec = timekeeper.xtime.tv_sec; |
618 | boot.tv_nsec = timekeeper.xtime.tv_nsec; |
619 | } |
620 | set_normalized_timespec(&timekeeper.wall_to_monotonic, |
621 | -boot.tv_sec, -boot.tv_nsec); |
622 | update_rt_offset(); |
623 | timekeeper.total_sleep_time.tv_sec = 0; |
624 | timekeeper.total_sleep_time.tv_nsec = 0; |
625 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
626 | } |
627 | |
628 | /* time in seconds when suspend began */ |
629 | static struct timespec timekeeping_suspend_time; |
630 | |
631 | static void update_sleep_time(struct timespec t) |
632 | { |
633 | timekeeper.total_sleep_time = t; |
634 | timekeeper.offs_boot = timespec_to_ktime(t); |
635 | } |
636 | |
637 | /** |
638 | * __timekeeping_inject_sleeptime - Internal function to add sleep interval |
639 | * @delta: pointer to a timespec delta value |
640 | * |
641 | * Takes a timespec offset measuring a suspend interval and properly |
642 | * adds the sleep offset to the timekeeping variables. |
643 | */ |
644 | static void __timekeeping_inject_sleeptime(struct timespec *delta) |
645 | { |
646 | if (!timespec_valid(delta)) { |
647 | printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid " |
648 | "sleep delta value!\n"); |
649 | return; |
650 | } |
651 | |
652 | timekeeper.xtime = timespec_add(timekeeper.xtime, *delta); |
653 | timekeeper.wall_to_monotonic = |
654 | timespec_sub(timekeeper.wall_to_monotonic, *delta); |
655 | update_sleep_time(timespec_add(timekeeper.total_sleep_time, *delta)); |
656 | } |
657 | |
658 | |
659 | /** |
660 | * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values |
661 | * @delta: pointer to a timespec delta value |
662 | * |
663 | * This hook is for architectures that cannot support read_persistent_clock |
664 | * because their RTC/persistent clock is only accessible when irqs are enabled. |
665 | * |
666 | * This function should only be called by rtc_resume(), and allows |
667 | * a suspend offset to be injected into the timekeeping values. |
668 | */ |
669 | void timekeeping_inject_sleeptime(struct timespec *delta) |
670 | { |
671 | unsigned long flags; |
672 | struct timespec ts; |
673 | |
674 | /* Make sure we don't set the clock twice */ |
675 | read_persistent_clock(&ts); |
676 | if (!(ts.tv_sec == 0 && ts.tv_nsec == 0)) |
677 | return; |
678 | |
679 | write_seqlock_irqsave(&timekeeper.lock, flags); |
680 | |
681 | timekeeping_forward_now(); |
682 | |
683 | __timekeeping_inject_sleeptime(delta); |
684 | |
685 | timekeeping_update(true); |
686 | |
687 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
688 | |
689 | /* signal hrtimers about time change */ |
690 | clock_was_set(); |
691 | } |
692 | |
693 | |
694 | /** |
695 | * timekeeping_resume - Resumes the generic timekeeping subsystem. |
696 | * |
697 | * This is for the generic clocksource timekeeping. |
698 | * xtime/wall_to_monotonic/jiffies/etc are |
699 | * still managed by arch specific suspend/resume code. |
700 | */ |
701 | static void timekeeping_resume(void) |
702 | { |
703 | unsigned long flags; |
704 | struct timespec ts; |
705 | |
706 | read_persistent_clock(&ts); |
707 | |
708 | clocksource_resume(); |
709 | |
710 | write_seqlock_irqsave(&timekeeper.lock, flags); |
711 | |
712 | if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { |
713 | ts = timespec_sub(ts, timekeeping_suspend_time); |
714 | __timekeeping_inject_sleeptime(&ts); |
715 | } |
716 | /* re-base the last cycle value */ |
717 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
718 | timekeeper.ntp_error = 0; |
719 | timekeeping_suspended = 0; |
720 | timekeeping_update(false); |
721 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
722 | |
723 | touch_softlockup_watchdog(); |
724 | |
725 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); |
726 | |
727 | /* Resume hrtimers */ |
728 | hrtimers_resume(); |
729 | } |
730 | |
731 | static int timekeeping_suspend(void) |
732 | { |
733 | unsigned long flags; |
734 | struct timespec delta, delta_delta; |
735 | static struct timespec old_delta; |
736 | |
737 | read_persistent_clock(&timekeeping_suspend_time); |
738 | |
739 | write_seqlock_irqsave(&timekeeper.lock, flags); |
740 | timekeeping_forward_now(); |
741 | timekeeping_suspended = 1; |
742 | |
743 | /* |
744 | * To avoid drift caused by repeated suspend/resumes, |
745 | * which each can add ~1 second drift error, |
746 | * try to compensate so the difference in system time |
747 | * and persistent_clock time stays close to constant. |
748 | */ |
749 | delta = timespec_sub(timekeeper.xtime, timekeeping_suspend_time); |
750 | delta_delta = timespec_sub(delta, old_delta); |
751 | if (abs(delta_delta.tv_sec) >= 2) { |
752 | /* |
753 | * if delta_delta is too large, assume time correction |
754 | * has occured and set old_delta to the current delta. |
755 | */ |
756 | old_delta = delta; |
757 | } else { |
758 | /* Otherwise try to adjust old_system to compensate */ |
759 | timekeeping_suspend_time = |
760 | timespec_add(timekeeping_suspend_time, delta_delta); |
761 | } |
762 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
763 | |
764 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); |
765 | clocksource_suspend(); |
766 | |
767 | return 0; |
768 | } |
769 | |
770 | /* sysfs resume/suspend bits for timekeeping */ |
771 | static struct syscore_ops timekeeping_syscore_ops = { |
772 | .resume = timekeeping_resume, |
773 | .suspend = timekeeping_suspend, |
774 | }; |
775 | |
776 | static int __init timekeeping_init_ops(void) |
777 | { |
778 | register_syscore_ops(&timekeeping_syscore_ops); |
779 | return 0; |
780 | } |
781 | |
782 | device_initcall(timekeeping_init_ops); |
783 | |
784 | /* |
785 | * If the error is already larger, we look ahead even further |
786 | * to compensate for late or lost adjustments. |
787 | */ |
788 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
789 | s64 *offset) |
790 | { |
791 | s64 tick_error, i; |
792 | u32 look_ahead, adj; |
793 | s32 error2, mult; |
794 | |
795 | /* |
796 | * Use the current error value to determine how much to look ahead. |
797 | * The larger the error the slower we adjust for it to avoid problems |
798 | * with losing too many ticks, otherwise we would overadjust and |
799 | * produce an even larger error. The smaller the adjustment the |
800 | * faster we try to adjust for it, as lost ticks can do less harm |
801 | * here. This is tuned so that an error of about 1 msec is adjusted |
802 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
803 | */ |
804 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
805 | error2 = abs(error2); |
806 | for (look_ahead = 0; error2 > 0; look_ahead++) |
807 | error2 >>= 2; |
808 | |
809 | /* |
810 | * Now calculate the error in (1 << look_ahead) ticks, but first |
811 | * remove the single look ahead already included in the error. |
812 | */ |
813 | tick_error = ntp_tick_length() >> (timekeeper.ntp_error_shift + 1); |
814 | tick_error -= timekeeper.xtime_interval >> 1; |
815 | error = ((error - tick_error) >> look_ahead) + tick_error; |
816 | |
817 | /* Finally calculate the adjustment shift value. */ |
818 | i = *interval; |
819 | mult = 1; |
820 | if (error < 0) { |
821 | error = -error; |
822 | *interval = -*interval; |
823 | *offset = -*offset; |
824 | mult = -1; |
825 | } |
826 | for (adj = 0; error > i; adj++) |
827 | error >>= 1; |
828 | |
829 | *interval <<= adj; |
830 | *offset <<= adj; |
831 | return mult << adj; |
832 | } |
833 | |
834 | /* |
835 | * Adjust the multiplier to reduce the error value, |
836 | * this is optimized for the most common adjustments of -1,0,1, |
837 | * for other values we can do a bit more work. |
838 | */ |
839 | static void timekeeping_adjust(s64 offset) |
840 | { |
841 | s64 error, interval = timekeeper.cycle_interval; |
842 | int adj; |
843 | |
844 | /* |
845 | * The point of this is to check if the error is greater than half |
846 | * an interval. |
847 | * |
848 | * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs. |
849 | * |
850 | * Note we subtract one in the shift, so that error is really error*2. |
851 | * This "saves" dividing(shifting) interval twice, but keeps the |
852 | * (error > interval) comparison as still measuring if error is |
853 | * larger than half an interval. |
854 | * |
855 | * Note: It does not "save" on aggravation when reading the code. |
856 | */ |
857 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
858 | if (error > interval) { |
859 | /* |
860 | * We now divide error by 4(via shift), which checks if |
861 | * the error is greater than twice the interval. |
862 | * If it is greater, we need a bigadjust, if its smaller, |
863 | * we can adjust by 1. |
864 | */ |
865 | error >>= 2; |
866 | /* |
867 | * XXX - In update_wall_time, we round up to the next |
868 | * nanosecond, and store the amount rounded up into |
869 | * the error. This causes the likely below to be unlikely. |
870 | * |
871 | * The proper fix is to avoid rounding up by using |
872 | * the high precision timekeeper.xtime_nsec instead of |
873 | * xtime.tv_nsec everywhere. Fixing this will take some |
874 | * time. |
875 | */ |
876 | if (likely(error <= interval)) |
877 | adj = 1; |
878 | else |
879 | adj = timekeeping_bigadjust(error, &interval, &offset); |
880 | } else if (error < -interval) { |
881 | /* See comment above, this is just switched for the negative */ |
882 | error >>= 2; |
883 | if (likely(error >= -interval)) { |
884 | adj = -1; |
885 | interval = -interval; |
886 | offset = -offset; |
887 | } else |
888 | adj = timekeeping_bigadjust(error, &interval, &offset); |
889 | } else /* No adjustment needed */ |
890 | return; |
891 | |
892 | if (unlikely(timekeeper.clock->maxadj && |
893 | (timekeeper.mult + adj > |
894 | timekeeper.clock->mult + timekeeper.clock->maxadj))) { |
895 | printk_once(KERN_WARNING |
896 | "Adjusting %s more than 11%% (%ld vs %ld)\n", |
897 | timekeeper.clock->name, (long)timekeeper.mult + adj, |
898 | (long)timekeeper.clock->mult + |
899 | timekeeper.clock->maxadj); |
900 | } |
901 | /* |
902 | * So the following can be confusing. |
903 | * |
904 | * To keep things simple, lets assume adj == 1 for now. |
905 | * |
906 | * When adj != 1, remember that the interval and offset values |
907 | * have been appropriately scaled so the math is the same. |
908 | * |
909 | * The basic idea here is that we're increasing the multiplier |
910 | * by one, this causes the xtime_interval to be incremented by |
911 | * one cycle_interval. This is because: |
912 | * xtime_interval = cycle_interval * mult |
913 | * So if mult is being incremented by one: |
914 | * xtime_interval = cycle_interval * (mult + 1) |
915 | * Its the same as: |
916 | * xtime_interval = (cycle_interval * mult) + cycle_interval |
917 | * Which can be shortened to: |
918 | * xtime_interval += cycle_interval |
919 | * |
920 | * So offset stores the non-accumulated cycles. Thus the current |
921 | * time (in shifted nanoseconds) is: |
922 | * now = (offset * adj) + xtime_nsec |
923 | * Now, even though we're adjusting the clock frequency, we have |
924 | * to keep time consistent. In other words, we can't jump back |
925 | * in time, and we also want to avoid jumping forward in time. |
926 | * |
927 | * So given the same offset value, we need the time to be the same |
928 | * both before and after the freq adjustment. |
929 | * now = (offset * adj_1) + xtime_nsec_1 |
930 | * now = (offset * adj_2) + xtime_nsec_2 |
931 | * So: |
932 | * (offset * adj_1) + xtime_nsec_1 = |
933 | * (offset * adj_2) + xtime_nsec_2 |
934 | * And we know: |
935 | * adj_2 = adj_1 + 1 |
936 | * So: |
937 | * (offset * adj_1) + xtime_nsec_1 = |
938 | * (offset * (adj_1+1)) + xtime_nsec_2 |
939 | * (offset * adj_1) + xtime_nsec_1 = |
940 | * (offset * adj_1) + offset + xtime_nsec_2 |
941 | * Canceling the sides: |
942 | * xtime_nsec_1 = offset + xtime_nsec_2 |
943 | * Which gives us: |
944 | * xtime_nsec_2 = xtime_nsec_1 - offset |
945 | * Which simplfies to: |
946 | * xtime_nsec -= offset |
947 | * |
948 | * XXX - TODO: Doc ntp_error calculation. |
949 | */ |
950 | timekeeper.mult += adj; |
951 | timekeeper.xtime_interval += interval; |
952 | timekeeper.xtime_nsec -= offset; |
953 | timekeeper.ntp_error -= (interval - offset) << |
954 | timekeeper.ntp_error_shift; |
955 | } |
956 | |
957 | |
958 | /** |
959 | * logarithmic_accumulation - shifted accumulation of cycles |
960 | * |
961 | * This functions accumulates a shifted interval of cycles into |
962 | * into a shifted interval nanoseconds. Allows for O(log) accumulation |
963 | * loop. |
964 | * |
965 | * Returns the unconsumed cycles. |
966 | */ |
967 | static cycle_t logarithmic_accumulation(cycle_t offset, int shift) |
968 | { |
969 | u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; |
970 | u64 raw_nsecs; |
971 | |
972 | /* If the offset is smaller than a shifted interval, do nothing */ |
973 | if (offset < timekeeper.cycle_interval<<shift) |
974 | return offset; |
975 | |
976 | /* Accumulate one shifted interval */ |
977 | offset -= timekeeper.cycle_interval << shift; |
978 | timekeeper.clock->cycle_last += timekeeper.cycle_interval << shift; |
979 | |
980 | timekeeper.xtime_nsec += timekeeper.xtime_interval << shift; |
981 | while (timekeeper.xtime_nsec >= nsecps) { |
982 | int leap; |
983 | timekeeper.xtime_nsec -= nsecps; |
984 | timekeeper.xtime.tv_sec++; |
985 | leap = second_overflow(timekeeper.xtime.tv_sec); |
986 | timekeeper.xtime.tv_sec += leap; |
987 | timekeeper.wall_to_monotonic.tv_sec -= leap; |
988 | if (leap) |
989 | clock_was_set_delayed(); |
990 | } |
991 | |
992 | /* Accumulate raw time */ |
993 | raw_nsecs = timekeeper.raw_interval << shift; |
994 | raw_nsecs += timekeeper.raw_time.tv_nsec; |
995 | if (raw_nsecs >= NSEC_PER_SEC) { |
996 | u64 raw_secs = raw_nsecs; |
997 | raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); |
998 | timekeeper.raw_time.tv_sec += raw_secs; |
999 | } |
1000 | timekeeper.raw_time.tv_nsec = raw_nsecs; |
1001 | |
1002 | /* Accumulate error between NTP and clock interval */ |
1003 | timekeeper.ntp_error += ntp_tick_length() << shift; |
1004 | timekeeper.ntp_error -= |
1005 | (timekeeper.xtime_interval + timekeeper.xtime_remainder) << |
1006 | (timekeeper.ntp_error_shift + shift); |
1007 | |
1008 | return offset; |
1009 | } |
1010 | |
1011 | |
1012 | /** |
1013 | * update_wall_time - Uses the current clocksource to increment the wall time |
1014 | * |
1015 | */ |
1016 | static void update_wall_time(void) |
1017 | { |
1018 | struct clocksource *clock; |
1019 | cycle_t offset; |
1020 | int shift = 0, maxshift; |
1021 | unsigned long flags; |
1022 | |
1023 | write_seqlock_irqsave(&timekeeper.lock, flags); |
1024 | |
1025 | /* Make sure we're fully resumed: */ |
1026 | if (unlikely(timekeeping_suspended)) |
1027 | goto out; |
1028 | |
1029 | clock = timekeeper.clock; |
1030 | |
1031 | #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET |
1032 | offset = timekeeper.cycle_interval; |
1033 | #else |
1034 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; |
1035 | #endif |
1036 | timekeeper.xtime_nsec = (s64)timekeeper.xtime.tv_nsec << |
1037 | timekeeper.shift; |
1038 | |
1039 | /* |
1040 | * With NO_HZ we may have to accumulate many cycle_intervals |
1041 | * (think "ticks") worth of time at once. To do this efficiently, |
1042 | * we calculate the largest doubling multiple of cycle_intervals |
1043 | * that is smaller than the offset. We then accumulate that |
1044 | * chunk in one go, and then try to consume the next smaller |
1045 | * doubled multiple. |
1046 | */ |
1047 | shift = ilog2(offset) - ilog2(timekeeper.cycle_interval); |
1048 | shift = max(0, shift); |
1049 | /* Bound shift to one less than what overflows tick_length */ |
1050 | maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; |
1051 | shift = min(shift, maxshift); |
1052 | while (offset >= timekeeper.cycle_interval) { |
1053 | offset = logarithmic_accumulation(offset, shift); |
1054 | if(offset < timekeeper.cycle_interval<<shift) |
1055 | shift--; |
1056 | } |
1057 | |
1058 | /* correct the clock when NTP error is too big */ |
1059 | timekeeping_adjust(offset); |
1060 | |
1061 | /* |
1062 | * Since in the loop above, we accumulate any amount of time |
1063 | * in xtime_nsec over a second into xtime.tv_sec, its possible for |
1064 | * xtime_nsec to be fairly small after the loop. Further, if we're |
1065 | * slightly speeding the clocksource up in timekeeping_adjust(), |
1066 | * its possible the required corrective factor to xtime_nsec could |
1067 | * cause it to underflow. |
1068 | * |
1069 | * Now, we cannot simply roll the accumulated second back, since |
1070 | * the NTP subsystem has been notified via second_overflow. So |
1071 | * instead we push xtime_nsec forward by the amount we underflowed, |
1072 | * and add that amount into the error. |
1073 | * |
1074 | * We'll correct this error next time through this function, when |
1075 | * xtime_nsec is not as small. |
1076 | */ |
1077 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { |
1078 | s64 neg = -(s64)timekeeper.xtime_nsec; |
1079 | timekeeper.xtime_nsec = 0; |
1080 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; |
1081 | } |
1082 | |
1083 | |
1084 | /* |
1085 | * Store full nanoseconds into xtime after rounding it up and |
1086 | * add the remainder to the error difference. |
1087 | */ |
1088 | timekeeper.xtime.tv_nsec = ((s64)timekeeper.xtime_nsec >> |
1089 | timekeeper.shift) + 1; |
1090 | timekeeper.xtime_nsec -= (s64)timekeeper.xtime.tv_nsec << |
1091 | timekeeper.shift; |
1092 | timekeeper.ntp_error += timekeeper.xtime_nsec << |
1093 | timekeeper.ntp_error_shift; |
1094 | |
1095 | /* |
1096 | * Finally, make sure that after the rounding |
1097 | * xtime.tv_nsec isn't larger than NSEC_PER_SEC |
1098 | */ |
1099 | if (unlikely(timekeeper.xtime.tv_nsec >= NSEC_PER_SEC)) { |
1100 | int leap; |
1101 | timekeeper.xtime.tv_nsec -= NSEC_PER_SEC; |
1102 | timekeeper.xtime.tv_sec++; |
1103 | leap = second_overflow(timekeeper.xtime.tv_sec); |
1104 | timekeeper.xtime.tv_sec += leap; |
1105 | timekeeper.wall_to_monotonic.tv_sec -= leap; |
1106 | if (leap) |
1107 | clock_was_set_delayed(); |
1108 | } |
1109 | |
1110 | timekeeping_update(false); |
1111 | |
1112 | out: |
1113 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
1114 | |
1115 | } |
1116 | |
1117 | /** |
1118 | * getboottime - Return the real time of system boot. |
1119 | * @ts: pointer to the timespec to be set |
1120 | * |
1121 | * Returns the wall-time of boot in a timespec. |
1122 | * |
1123 | * This is based on the wall_to_monotonic offset and the total suspend |
1124 | * time. Calls to settimeofday will affect the value returned (which |
1125 | * basically means that however wrong your real time clock is at boot time, |
1126 | * you get the right time here). |
1127 | */ |
1128 | void getboottime(struct timespec *ts) |
1129 | { |
1130 | struct timespec boottime = { |
1131 | .tv_sec = timekeeper.wall_to_monotonic.tv_sec + |
1132 | timekeeper.total_sleep_time.tv_sec, |
1133 | .tv_nsec = timekeeper.wall_to_monotonic.tv_nsec + |
1134 | timekeeper.total_sleep_time.tv_nsec |
1135 | }; |
1136 | |
1137 | set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); |
1138 | } |
1139 | EXPORT_SYMBOL_GPL(getboottime); |
1140 | |
1141 | |
1142 | /** |
1143 | * get_monotonic_boottime - Returns monotonic time since boot |
1144 | * @ts: pointer to the timespec to be set |
1145 | * |
1146 | * Returns the monotonic time since boot in a timespec. |
1147 | * |
1148 | * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also |
1149 | * includes the time spent in suspend. |
1150 | */ |
1151 | void get_monotonic_boottime(struct timespec *ts) |
1152 | { |
1153 | struct timespec tomono, sleep; |
1154 | unsigned int seq; |
1155 | s64 nsecs; |
1156 | |
1157 | WARN_ON(timekeeping_suspended); |
1158 | |
1159 | do { |
1160 | seq = read_seqbegin(&timekeeper.lock); |
1161 | *ts = timekeeper.xtime; |
1162 | tomono = timekeeper.wall_to_monotonic; |
1163 | sleep = timekeeper.total_sleep_time; |
1164 | nsecs = timekeeping_get_ns(); |
1165 | |
1166 | } while (read_seqretry(&timekeeper.lock, seq)); |
1167 | |
1168 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec, |
1169 | ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec + nsecs); |
1170 | } |
1171 | EXPORT_SYMBOL_GPL(get_monotonic_boottime); |
1172 | |
1173 | /** |
1174 | * ktime_get_boottime - Returns monotonic time since boot in a ktime |
1175 | * |
1176 | * Returns the monotonic time since boot in a ktime |
1177 | * |
1178 | * This is similar to CLOCK_MONTONIC/ktime_get, but also |
1179 | * includes the time spent in suspend. |
1180 | */ |
1181 | ktime_t ktime_get_boottime(void) |
1182 | { |
1183 | struct timespec ts; |
1184 | |
1185 | get_monotonic_boottime(&ts); |
1186 | return timespec_to_ktime(ts); |
1187 | } |
1188 | EXPORT_SYMBOL_GPL(ktime_get_boottime); |
1189 | |
1190 | /** |
1191 | * monotonic_to_bootbased - Convert the monotonic time to boot based. |
1192 | * @ts: pointer to the timespec to be converted |
1193 | */ |
1194 | void monotonic_to_bootbased(struct timespec *ts) |
1195 | { |
1196 | *ts = timespec_add(*ts, timekeeper.total_sleep_time); |
1197 | } |
1198 | EXPORT_SYMBOL_GPL(monotonic_to_bootbased); |
1199 | |
1200 | unsigned long get_seconds(void) |
1201 | { |
1202 | return timekeeper.xtime.tv_sec; |
1203 | } |
1204 | EXPORT_SYMBOL(get_seconds); |
1205 | |
1206 | struct timespec __current_kernel_time(void) |
1207 | { |
1208 | return timekeeper.xtime; |
1209 | } |
1210 | |
1211 | struct timespec current_kernel_time(void) |
1212 | { |
1213 | struct timespec now; |
1214 | unsigned long seq; |
1215 | |
1216 | do { |
1217 | seq = read_seqbegin(&timekeeper.lock); |
1218 | |
1219 | now = timekeeper.xtime; |
1220 | } while (read_seqretry(&timekeeper.lock, seq)); |
1221 | |
1222 | return now; |
1223 | } |
1224 | EXPORT_SYMBOL(current_kernel_time); |
1225 | |
1226 | struct timespec get_monotonic_coarse(void) |
1227 | { |
1228 | struct timespec now, mono; |
1229 | unsigned long seq; |
1230 | |
1231 | do { |
1232 | seq = read_seqbegin(&timekeeper.lock); |
1233 | |
1234 | now = timekeeper.xtime; |
1235 | mono = timekeeper.wall_to_monotonic; |
1236 | } while (read_seqretry(&timekeeper.lock, seq)); |
1237 | |
1238 | set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, |
1239 | now.tv_nsec + mono.tv_nsec); |
1240 | return now; |
1241 | } |
1242 | |
1243 | /* |
1244 | * The 64-bit jiffies value is not atomic - you MUST NOT read it |
1245 | * without sampling the sequence number in xtime_lock. |
1246 | * jiffies is defined in the linker script... |
1247 | */ |
1248 | void do_timer(unsigned long ticks) |
1249 | { |
1250 | jiffies_64 += ticks; |
1251 | update_wall_time(); |
1252 | calc_global_load(ticks); |
1253 | } |
1254 | |
1255 | /** |
1256 | * get_xtime_and_monotonic_and_sleep_offset() - get xtime, wall_to_monotonic, |
1257 | * and sleep offsets. |
1258 | * @xtim: pointer to timespec to be set with xtime |
1259 | * @wtom: pointer to timespec to be set with wall_to_monotonic |
1260 | * @sleep: pointer to timespec to be set with time in suspend |
1261 | */ |
1262 | void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, |
1263 | struct timespec *wtom, struct timespec *sleep) |
1264 | { |
1265 | unsigned long seq; |
1266 | |
1267 | do { |
1268 | seq = read_seqbegin(&timekeeper.lock); |
1269 | *xtim = timekeeper.xtime; |
1270 | *wtom = timekeeper.wall_to_monotonic; |
1271 | *sleep = timekeeper.total_sleep_time; |
1272 | } while (read_seqretry(&timekeeper.lock, seq)); |
1273 | } |
1274 | |
1275 | #ifdef CONFIG_HIGH_RES_TIMERS |
1276 | /** |
1277 | * ktime_get_update_offsets - hrtimer helper |
1278 | * @offs_real: pointer to storage for monotonic -> realtime offset |
1279 | * @offs_boot: pointer to storage for monotonic -> boottime offset |
1280 | * |
1281 | * Returns current monotonic time and updates the offsets |
1282 | * Called from hrtimer_interupt() or retrigger_next_event() |
1283 | */ |
1284 | ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot) |
1285 | { |
1286 | ktime_t now; |
1287 | unsigned int seq; |
1288 | u64 secs, nsecs; |
1289 | |
1290 | do { |
1291 | seq = read_seqbegin(&timekeeper.lock); |
1292 | |
1293 | secs = timekeeper.xtime.tv_sec; |
1294 | nsecs = timekeeper.xtime.tv_nsec; |
1295 | nsecs += timekeeping_get_ns(); |
1296 | /* If arch requires, add in gettimeoffset() */ |
1297 | nsecs += arch_gettimeoffset(); |
1298 | |
1299 | *offs_real = timekeeper.offs_real; |
1300 | *offs_boot = timekeeper.offs_boot; |
1301 | } while (read_seqretry(&timekeeper.lock, seq)); |
1302 | |
1303 | now = ktime_add_ns(ktime_set(secs, 0), nsecs); |
1304 | now = ktime_sub(now, *offs_real); |
1305 | return now; |
1306 | } |
1307 | #endif |
1308 | |
1309 | /** |
1310 | * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format |
1311 | */ |
1312 | ktime_t ktime_get_monotonic_offset(void) |
1313 | { |
1314 | unsigned long seq; |
1315 | struct timespec wtom; |
1316 | |
1317 | do { |
1318 | seq = read_seqbegin(&timekeeper.lock); |
1319 | wtom = timekeeper.wall_to_monotonic; |
1320 | } while (read_seqretry(&timekeeper.lock, seq)); |
1321 | |
1322 | return timespec_to_ktime(wtom); |
1323 | } |
1324 | EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset); |
1325 | |
1326 | |
1327 | /** |
1328 | * xtime_update() - advances the timekeeping infrastructure |
1329 | * @ticks: number of ticks, that have elapsed since the last call. |
1330 | * |
1331 | * Must be called with interrupts disabled. |
1332 | */ |
1333 | void xtime_update(unsigned long ticks) |
1334 | { |
1335 | write_seqlock(&xtime_lock); |
1336 | do_timer(ticks); |
1337 | write_sequnlock(&xtime_lock); |
1338 | } |
1339 |
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v2.6.34-rc5
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