Commit | Line | Data |
---|---|---|
8524070b | 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/sysdev.h> | |
17 | #include <linux/clocksource.h> | |
18 | #include <linux/jiffies.h> | |
19 | #include <linux/time.h> | |
20 | #include <linux/tick.h> | |
21 | ||
22 | ||
23 | /* | |
24 | * This read-write spinlock protects us from races in SMP while | |
25 | * playing with xtime and avenrun. | |
26 | */ | |
ba2a631b | 27 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); |
8524070b | 28 | |
29 | ||
30 | /* | |
31 | * The current time | |
32 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected | |
33 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged | |
34 | * at zero at system boot time, so wall_to_monotonic will be negative, | |
35 | * however, we will ALWAYS keep the tv_nsec part positive so we can use | |
36 | * the usual normalization. | |
7c3f1a57 TJ |
37 | * |
38 | * wall_to_monotonic is moved after resume from suspend for the monotonic | |
39 | * time not to jump. We need to add total_sleep_time to wall_to_monotonic | |
40 | * to get the real boot based time offset. | |
41 | * | |
42 | * - wall_to_monotonic is no longer the boot time, getboottime must be | |
43 | * used instead. | |
8524070b | 44 | */ |
45 | struct timespec xtime __attribute__ ((aligned (16))); | |
46 | struct timespec wall_to_monotonic __attribute__ ((aligned (16))); | |
7c3f1a57 | 47 | static unsigned long total_sleep_time; /* seconds */ |
8524070b | 48 | |
17c38b74 | 49 | static struct timespec xtime_cache __attribute__ ((aligned (16))); |
1001d0a9 | 50 | void update_xtime_cache(u64 nsec) |
17c38b74 | 51 | { |
52 | xtime_cache = xtime; | |
53 | timespec_add_ns(&xtime_cache, nsec); | |
54 | } | |
17c38b74 | 55 | |
7dffa3c6 | 56 | struct clocksource *clock; |
8524070b | 57 | |
58 | ||
59 | #ifdef CONFIG_GENERIC_TIME | |
60 | /** | |
9a055117 | 61 | * clocksource_forward_now - update clock to the current time |
8524070b | 62 | * |
9a055117 RZ |
63 | * Forward the current clock to update its state since the last call to |
64 | * update_wall_time(). This is useful before significant clock changes, | |
65 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 66 | */ |
9a055117 | 67 | static void clocksource_forward_now(void) |
8524070b | 68 | { |
69 | cycle_t cycle_now, cycle_delta; | |
9a055117 | 70 | s64 nsec; |
8524070b | 71 | |
8524070b | 72 | cycle_now = clocksource_read(clock); |
8524070b | 73 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 74 | clock->cycle_last = cycle_now; |
8524070b | 75 | |
9a055117 RZ |
76 | nsec = cyc2ns(clock, cycle_delta); |
77 | timespec_add_ns(&xtime, nsec); | |
2d42244a JS |
78 | |
79 | nsec = ((s64)cycle_delta * clock->mult_orig) >> clock->shift; | |
80 | clock->raw_time.tv_nsec += nsec; | |
8524070b | 81 | } |
82 | ||
83 | /** | |
efd9ac86 | 84 | * getnstimeofday - Returns the time of day in a timespec |
8524070b | 85 | * @ts: pointer to the timespec to be set |
86 | * | |
efd9ac86 | 87 | * Returns the time of day in a timespec. |
8524070b | 88 | */ |
efd9ac86 | 89 | void getnstimeofday(struct timespec *ts) |
8524070b | 90 | { |
9a055117 | 91 | cycle_t cycle_now, cycle_delta; |
8524070b | 92 | unsigned long seq; |
93 | s64 nsecs; | |
94 | ||
95 | do { | |
96 | seq = read_seqbegin(&xtime_lock); | |
97 | ||
98 | *ts = xtime; | |
9a055117 RZ |
99 | |
100 | /* read clocksource: */ | |
101 | cycle_now = clocksource_read(clock); | |
102 | ||
103 | /* calculate the delta since the last update_wall_time: */ | |
104 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
105 | ||
106 | /* convert to nanoseconds: */ | |
107 | nsecs = cyc2ns(clock, cycle_delta); | |
8524070b | 108 | |
109 | } while (read_seqretry(&xtime_lock, seq)); | |
110 | ||
111 | timespec_add_ns(ts, nsecs); | |
112 | } | |
113 | ||
8524070b | 114 | EXPORT_SYMBOL(getnstimeofday); |
115 | ||
116 | /** | |
117 | * do_gettimeofday - Returns the time of day in a timeval | |
118 | * @tv: pointer to the timeval to be set | |
119 | * | |
efd9ac86 | 120 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b | 121 | */ |
122 | void do_gettimeofday(struct timeval *tv) | |
123 | { | |
124 | struct timespec now; | |
125 | ||
efd9ac86 | 126 | getnstimeofday(&now); |
8524070b | 127 | tv->tv_sec = now.tv_sec; |
128 | tv->tv_usec = now.tv_nsec/1000; | |
129 | } | |
130 | ||
131 | EXPORT_SYMBOL(do_gettimeofday); | |
132 | /** | |
133 | * do_settimeofday - Sets the time of day | |
134 | * @tv: pointer to the timespec variable containing the new time | |
135 | * | |
136 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
137 | */ | |
138 | int do_settimeofday(struct timespec *tv) | |
139 | { | |
9a055117 | 140 | struct timespec ts_delta; |
8524070b | 141 | unsigned long flags; |
8524070b | 142 | |
143 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
144 | return -EINVAL; | |
145 | ||
146 | write_seqlock_irqsave(&xtime_lock, flags); | |
147 | ||
9a055117 RZ |
148 | clocksource_forward_now(); |
149 | ||
150 | ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec; | |
151 | ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec; | |
152 | wall_to_monotonic = timespec_sub(wall_to_monotonic, ts_delta); | |
8524070b | 153 | |
9a055117 | 154 | xtime = *tv; |
8524070b | 155 | |
1001d0a9 | 156 | update_xtime_cache(0); |
8524070b | 157 | |
158 | clock->error = 0; | |
159 | ntp_clear(); | |
160 | ||
161 | update_vsyscall(&xtime, clock); | |
162 | ||
163 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
164 | ||
165 | /* signal hrtimers about time change */ | |
166 | clock_was_set(); | |
167 | ||
168 | return 0; | |
169 | } | |
170 | ||
171 | EXPORT_SYMBOL(do_settimeofday); | |
172 | ||
173 | /** | |
174 | * change_clocksource - Swaps clocksources if a new one is available | |
175 | * | |
176 | * Accumulates current time interval and initializes new clocksource | |
177 | */ | |
178 | static void change_clocksource(void) | |
179 | { | |
180 | struct clocksource *new; | |
8524070b | 181 | |
182 | new = clocksource_get_next(); | |
183 | ||
184 | if (clock == new) | |
185 | return; | |
186 | ||
9a055117 | 187 | clocksource_forward_now(); |
8524070b | 188 | |
2d42244a JS |
189 | new->raw_time = clock->raw_time; |
190 | ||
8524070b | 191 | clock = new; |
9a055117 RZ |
192 | clock->cycle_last = 0; |
193 | clock->cycle_last = clocksource_read(new); | |
8524070b | 194 | clock->error = 0; |
195 | clock->xtime_nsec = 0; | |
10a398d0 | 196 | clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); |
8524070b | 197 | |
198 | tick_clock_notify(); | |
199 | ||
92896bd9 LT |
200 | /* |
201 | * We're holding xtime lock and waking up klogd would deadlock | |
202 | * us on enqueue. So no printing! | |
8524070b | 203 | printk(KERN_INFO "Time: %s clocksource has been installed.\n", |
204 | clock->name); | |
92896bd9 | 205 | */ |
8524070b | 206 | } |
207 | #else | |
9a055117 | 208 | static inline void clocksource_forward_now(void) { } |
8524070b | 209 | static inline void change_clocksource(void) { } |
210 | #endif | |
211 | ||
2d42244a JS |
212 | /** |
213 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
214 | * @ts: pointer to the timespec to be set | |
215 | * | |
216 | * Returns the raw monotonic time (completely un-modified by ntp) | |
217 | */ | |
218 | void getrawmonotonic(struct timespec *ts) | |
219 | { | |
220 | unsigned long seq; | |
221 | s64 nsecs; | |
222 | cycle_t cycle_now, cycle_delta; | |
223 | ||
224 | do { | |
225 | seq = read_seqbegin(&xtime_lock); | |
226 | ||
227 | /* read clocksource: */ | |
228 | cycle_now = clocksource_read(clock); | |
229 | ||
230 | /* calculate the delta since the last update_wall_time: */ | |
231 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
232 | ||
233 | /* convert to nanoseconds: */ | |
234 | nsecs = ((s64)cycle_delta * clock->mult_orig) >> clock->shift; | |
235 | ||
236 | *ts = clock->raw_time; | |
237 | ||
238 | } while (read_seqretry(&xtime_lock, seq)); | |
239 | ||
240 | timespec_add_ns(ts, nsecs); | |
241 | } | |
242 | EXPORT_SYMBOL(getrawmonotonic); | |
243 | ||
244 | ||
8524070b | 245 | /** |
cf4fc6cb | 246 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 247 | */ |
cf4fc6cb | 248 | int timekeeping_valid_for_hres(void) |
8524070b | 249 | { |
250 | unsigned long seq; | |
251 | int ret; | |
252 | ||
253 | do { | |
254 | seq = read_seqbegin(&xtime_lock); | |
255 | ||
256 | ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; | |
257 | ||
258 | } while (read_seqretry(&xtime_lock, seq)); | |
259 | ||
260 | return ret; | |
261 | } | |
262 | ||
263 | /** | |
264 | * read_persistent_clock - Return time in seconds from the persistent clock. | |
265 | * | |
266 | * Weak dummy function for arches that do not yet support it. | |
267 | * Returns seconds from epoch using the battery backed persistent clock. | |
268 | * Returns zero if unsupported. | |
269 | * | |
270 | * XXX - Do be sure to remove it once all arches implement it. | |
271 | */ | |
272 | unsigned long __attribute__((weak)) read_persistent_clock(void) | |
273 | { | |
274 | return 0; | |
275 | } | |
276 | ||
277 | /* | |
278 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
279 | */ | |
280 | void __init timekeeping_init(void) | |
281 | { | |
282 | unsigned long flags; | |
283 | unsigned long sec = read_persistent_clock(); | |
284 | ||
285 | write_seqlock_irqsave(&xtime_lock, flags); | |
286 | ||
7dffa3c6 | 287 | ntp_init(); |
8524070b | 288 | |
289 | clock = clocksource_get_next(); | |
10a398d0 | 290 | clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); |
8524070b | 291 | clock->cycle_last = clocksource_read(clock); |
292 | ||
293 | xtime.tv_sec = sec; | |
294 | xtime.tv_nsec = 0; | |
295 | set_normalized_timespec(&wall_to_monotonic, | |
296 | -xtime.tv_sec, -xtime.tv_nsec); | |
1001d0a9 | 297 | update_xtime_cache(0); |
7c3f1a57 | 298 | total_sleep_time = 0; |
8524070b | 299 | write_sequnlock_irqrestore(&xtime_lock, flags); |
300 | } | |
301 | ||
302 | /* flag for if timekeeping is suspended */ | |
303 | static int timekeeping_suspended; | |
304 | /* time in seconds when suspend began */ | |
305 | static unsigned long timekeeping_suspend_time; | |
306 | ||
307 | /** | |
308 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
309 | * @dev: unused | |
310 | * | |
311 | * This is for the generic clocksource timekeeping. | |
312 | * xtime/wall_to_monotonic/jiffies/etc are | |
313 | * still managed by arch specific suspend/resume code. | |
314 | */ | |
315 | static int timekeeping_resume(struct sys_device *dev) | |
316 | { | |
317 | unsigned long flags; | |
318 | unsigned long now = read_persistent_clock(); | |
319 | ||
d10ff3fb TG |
320 | clocksource_resume(); |
321 | ||
8524070b | 322 | write_seqlock_irqsave(&xtime_lock, flags); |
323 | ||
324 | if (now && (now > timekeeping_suspend_time)) { | |
325 | unsigned long sleep_length = now - timekeeping_suspend_time; | |
326 | ||
327 | xtime.tv_sec += sleep_length; | |
328 | wall_to_monotonic.tv_sec -= sleep_length; | |
7c3f1a57 | 329 | total_sleep_time += sleep_length; |
8524070b | 330 | } |
1001d0a9 | 331 | update_xtime_cache(0); |
8524070b | 332 | /* re-base the last cycle value */ |
d8bb6f4c | 333 | clock->cycle_last = 0; |
8524070b | 334 | clock->cycle_last = clocksource_read(clock); |
335 | clock->error = 0; | |
336 | timekeeping_suspended = 0; | |
337 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
338 | ||
339 | touch_softlockup_watchdog(); | |
340 | ||
341 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); | |
342 | ||
343 | /* Resume hrtimers */ | |
344 | hres_timers_resume(); | |
345 | ||
346 | return 0; | |
347 | } | |
348 | ||
349 | static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) | |
350 | { | |
351 | unsigned long flags; | |
352 | ||
3be90950 TG |
353 | timekeeping_suspend_time = read_persistent_clock(); |
354 | ||
8524070b | 355 | write_seqlock_irqsave(&xtime_lock, flags); |
9a055117 | 356 | clocksource_forward_now(); |
8524070b | 357 | timekeeping_suspended = 1; |
8524070b | 358 | write_sequnlock_irqrestore(&xtime_lock, flags); |
359 | ||
360 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
361 | ||
362 | return 0; | |
363 | } | |
364 | ||
365 | /* sysfs resume/suspend bits for timekeeping */ | |
366 | static struct sysdev_class timekeeping_sysclass = { | |
af5ca3f4 | 367 | .name = "timekeeping", |
8524070b | 368 | .resume = timekeeping_resume, |
369 | .suspend = timekeeping_suspend, | |
8524070b | 370 | }; |
371 | ||
372 | static struct sys_device device_timer = { | |
373 | .id = 0, | |
374 | .cls = &timekeeping_sysclass, | |
375 | }; | |
376 | ||
377 | static int __init timekeeping_init_device(void) | |
378 | { | |
379 | int error = sysdev_class_register(&timekeeping_sysclass); | |
380 | if (!error) | |
381 | error = sysdev_register(&device_timer); | |
382 | return error; | |
383 | } | |
384 | ||
385 | device_initcall(timekeeping_init_device); | |
386 | ||
387 | /* | |
388 | * If the error is already larger, we look ahead even further | |
389 | * to compensate for late or lost adjustments. | |
390 | */ | |
391 | static __always_inline int clocksource_bigadjust(s64 error, s64 *interval, | |
392 | s64 *offset) | |
393 | { | |
394 | s64 tick_error, i; | |
395 | u32 look_ahead, adj; | |
396 | s32 error2, mult; | |
397 | ||
398 | /* | |
399 | * Use the current error value to determine how much to look ahead. | |
400 | * The larger the error the slower we adjust for it to avoid problems | |
401 | * with losing too many ticks, otherwise we would overadjust and | |
402 | * produce an even larger error. The smaller the adjustment the | |
403 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 404 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b | 405 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
406 | */ | |
7fc5c784 | 407 | error2 = clock->error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b | 408 | error2 = abs(error2); |
409 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
410 | error2 >>= 2; | |
411 | ||
412 | /* | |
413 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
414 | * remove the single look ahead already included in the error. | |
415 | */ | |
8383c423 | 416 | tick_error = tick_length >> (NTP_SCALE_SHIFT - clock->shift + 1); |
8524070b | 417 | tick_error -= clock->xtime_interval >> 1; |
418 | error = ((error - tick_error) >> look_ahead) + tick_error; | |
419 | ||
420 | /* Finally calculate the adjustment shift value. */ | |
421 | i = *interval; | |
422 | mult = 1; | |
423 | if (error < 0) { | |
424 | error = -error; | |
425 | *interval = -*interval; | |
426 | *offset = -*offset; | |
427 | mult = -1; | |
428 | } | |
429 | for (adj = 0; error > i; adj++) | |
430 | error >>= 1; | |
431 | ||
432 | *interval <<= adj; | |
433 | *offset <<= adj; | |
434 | return mult << adj; | |
435 | } | |
436 | ||
437 | /* | |
438 | * Adjust the multiplier to reduce the error value, | |
439 | * this is optimized for the most common adjustments of -1,0,1, | |
440 | * for other values we can do a bit more work. | |
441 | */ | |
71120f18 | 442 | static void clocksource_adjust(s64 offset) |
8524070b | 443 | { |
444 | s64 error, interval = clock->cycle_interval; | |
445 | int adj; | |
446 | ||
7fc5c784 | 447 | error = clock->error >> (NTP_SCALE_SHIFT - clock->shift - 1); |
8524070b | 448 | if (error > interval) { |
449 | error >>= 2; | |
450 | if (likely(error <= interval)) | |
451 | adj = 1; | |
452 | else | |
453 | adj = clocksource_bigadjust(error, &interval, &offset); | |
454 | } else if (error < -interval) { | |
455 | error >>= 2; | |
456 | if (likely(error >= -interval)) { | |
457 | adj = -1; | |
458 | interval = -interval; | |
459 | offset = -offset; | |
460 | } else | |
461 | adj = clocksource_bigadjust(error, &interval, &offset); | |
462 | } else | |
463 | return; | |
464 | ||
465 | clock->mult += adj; | |
466 | clock->xtime_interval += interval; | |
467 | clock->xtime_nsec -= offset; | |
468 | clock->error -= (interval - offset) << | |
7fc5c784 | 469 | (NTP_SCALE_SHIFT - clock->shift); |
8524070b | 470 | } |
471 | ||
472 | /** | |
473 | * update_wall_time - Uses the current clocksource to increment the wall time | |
474 | * | |
475 | * Called from the timer interrupt, must hold a write on xtime_lock. | |
476 | */ | |
477 | void update_wall_time(void) | |
478 | { | |
479 | cycle_t offset; | |
480 | ||
481 | /* Make sure we're fully resumed: */ | |
482 | if (unlikely(timekeeping_suspended)) | |
483 | return; | |
484 | ||
485 | #ifdef CONFIG_GENERIC_TIME | |
486 | offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask; | |
487 | #else | |
488 | offset = clock->cycle_interval; | |
489 | #endif | |
5cd1c9c5 | 490 | clock->xtime_nsec = (s64)xtime.tv_nsec << clock->shift; |
8524070b | 491 | |
492 | /* normally this loop will run just once, however in the | |
493 | * case of lost or late ticks, it will accumulate correctly. | |
494 | */ | |
495 | while (offset >= clock->cycle_interval) { | |
496 | /* accumulate one interval */ | |
8524070b | 497 | offset -= clock->cycle_interval; |
9a055117 | 498 | clock->cycle_last += clock->cycle_interval; |
8524070b | 499 | |
9a055117 | 500 | clock->xtime_nsec += clock->xtime_interval; |
8524070b | 501 | if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) { |
502 | clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift; | |
503 | xtime.tv_sec++; | |
504 | second_overflow(); | |
505 | } | |
506 | ||
2d42244a JS |
507 | clock->raw_time.tv_nsec += clock->raw_interval; |
508 | if (clock->raw_time.tv_nsec >= NSEC_PER_SEC) { | |
509 | clock->raw_time.tv_nsec -= NSEC_PER_SEC; | |
510 | clock->raw_time.tv_sec++; | |
511 | } | |
512 | ||
8524070b | 513 | /* accumulate error between NTP and clock interval */ |
8383c423 | 514 | clock->error += tick_length; |
7fc5c784 | 515 | clock->error -= clock->xtime_interval << (NTP_SCALE_SHIFT - clock->shift); |
8524070b | 516 | } |
517 | ||
518 | /* correct the clock when NTP error is too big */ | |
71120f18 | 519 | clocksource_adjust(offset); |
8524070b | 520 | |
6c9bacb4 | 521 | /* |
522 | * Since in the loop above, we accumulate any amount of time | |
523 | * in xtime_nsec over a second into xtime.tv_sec, its possible for | |
524 | * xtime_nsec to be fairly small after the loop. Further, if we're | |
525 | * slightly speeding the clocksource up in clocksource_adjust(), | |
526 | * its possible the required corrective factor to xtime_nsec could | |
527 | * cause it to underflow. | |
528 | * | |
529 | * Now, we cannot simply roll the accumulated second back, since | |
530 | * the NTP subsystem has been notified via second_overflow. So | |
531 | * instead we push xtime_nsec forward by the amount we underflowed, | |
532 | * and add that amount into the error. | |
533 | * | |
534 | * We'll correct this error next time through this function, when | |
535 | * xtime_nsec is not as small. | |
536 | */ | |
537 | if (unlikely((s64)clock->xtime_nsec < 0)) { | |
538 | s64 neg = -(s64)clock->xtime_nsec; | |
539 | clock->xtime_nsec = 0; | |
540 | clock->error += neg << (NTP_SCALE_SHIFT - clock->shift); | |
541 | } | |
542 | ||
5cd1c9c5 RZ |
543 | /* store full nanoseconds into xtime after rounding it up and |
544 | * add the remainder to the error difference. | |
545 | */ | |
546 | xtime.tv_nsec = ((s64)clock->xtime_nsec >> clock->shift) + 1; | |
8524070b | 547 | clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift; |
5cd1c9c5 | 548 | clock->error += clock->xtime_nsec << (NTP_SCALE_SHIFT - clock->shift); |
8524070b | 549 | |
17c38b74 | 550 | update_xtime_cache(cyc2ns(clock, offset)); |
551 | ||
8524070b | 552 | /* check to see if there is a new clocksource to use */ |
553 | change_clocksource(); | |
554 | update_vsyscall(&xtime, clock); | |
555 | } | |
7c3f1a57 TJ |
556 | |
557 | /** | |
558 | * getboottime - Return the real time of system boot. | |
559 | * @ts: pointer to the timespec to be set | |
560 | * | |
561 | * Returns the time of day in a timespec. | |
562 | * | |
563 | * This is based on the wall_to_monotonic offset and the total suspend | |
564 | * time. Calls to settimeofday will affect the value returned (which | |
565 | * basically means that however wrong your real time clock is at boot time, | |
566 | * you get the right time here). | |
567 | */ | |
568 | void getboottime(struct timespec *ts) | |
569 | { | |
570 | set_normalized_timespec(ts, | |
571 | - (wall_to_monotonic.tv_sec + total_sleep_time), | |
572 | - wall_to_monotonic.tv_nsec); | |
573 | } | |
574 | ||
575 | /** | |
576 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
577 | * @ts: pointer to the timespec to be converted | |
578 | */ | |
579 | void monotonic_to_bootbased(struct timespec *ts) | |
580 | { | |
581 | ts->tv_sec += total_sleep_time; | |
582 | } | |
2c6b47de | 583 | |
17c38b74 | 584 | unsigned long get_seconds(void) |
585 | { | |
586 | return xtime_cache.tv_sec; | |
587 | } | |
588 | EXPORT_SYMBOL(get_seconds); | |
589 | ||
590 | ||
2c6b47de | 591 | struct timespec current_kernel_time(void) |
592 | { | |
593 | struct timespec now; | |
594 | unsigned long seq; | |
595 | ||
596 | do { | |
597 | seq = read_seqbegin(&xtime_lock); | |
598 | ||
17c38b74 | 599 | now = xtime_cache; |
2c6b47de | 600 | } while (read_seqretry(&xtime_lock, seq)); |
601 | ||
602 | return now; | |
603 | } | |
2c6b47de | 604 | EXPORT_SYMBOL(current_kernel_time); |