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Commit | Line | Data |
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8524070b JS |
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 | |
dce48a84 | 25 | * playing with xtime. |
8524070b | 26 | */ |
ba2a631b | 27 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); |
8524070b JS |
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 JS |
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 | |
1c5745aa TG |
49 | /* flag for if timekeeping is suspended */ |
50 | int __read_mostly timekeeping_suspended; | |
51 | ||
17c38b74 | 52 | static struct timespec xtime_cache __attribute__ ((aligned (16))); |
1001d0a9 | 53 | void update_xtime_cache(u64 nsec) |
17c38b74 JS |
54 | { |
55 | xtime_cache = xtime; | |
56 | timespec_add_ns(&xtime_cache, nsec); | |
57 | } | |
17c38b74 | 58 | |
7dffa3c6 | 59 | struct clocksource *clock; |
8524070b JS |
60 | |
61 | ||
62 | #ifdef CONFIG_GENERIC_TIME | |
63 | /** | |
9a055117 | 64 | * clocksource_forward_now - update clock to the current time |
8524070b | 65 | * |
9a055117 RZ |
66 | * Forward the current clock to update its state since the last call to |
67 | * update_wall_time(). This is useful before significant clock changes, | |
68 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 69 | */ |
9a055117 | 70 | static void clocksource_forward_now(void) |
8524070b JS |
71 | { |
72 | cycle_t cycle_now, cycle_delta; | |
9a055117 | 73 | s64 nsec; |
8524070b | 74 | |
8524070b | 75 | cycle_now = clocksource_read(clock); |
8524070b | 76 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 77 | clock->cycle_last = cycle_now; |
8524070b | 78 | |
9a055117 | 79 | nsec = cyc2ns(clock, cycle_delta); |
7d27558c JS |
80 | |
81 | /* If arch requires, add in gettimeoffset() */ | |
82 | nsec += arch_gettimeoffset(); | |
83 | ||
9a055117 | 84 | timespec_add_ns(&xtime, nsec); |
2d42244a JS |
85 | |
86 | nsec = ((s64)cycle_delta * clock->mult_orig) >> clock->shift; | |
87 | clock->raw_time.tv_nsec += nsec; | |
8524070b JS |
88 | } |
89 | ||
90 | /** | |
efd9ac86 | 91 | * getnstimeofday - Returns the time of day in a timespec |
8524070b JS |
92 | * @ts: pointer to the timespec to be set |
93 | * | |
efd9ac86 | 94 | * Returns the time of day in a timespec. |
8524070b | 95 | */ |
efd9ac86 | 96 | void getnstimeofday(struct timespec *ts) |
8524070b | 97 | { |
9a055117 | 98 | cycle_t cycle_now, cycle_delta; |
8524070b JS |
99 | unsigned long seq; |
100 | s64 nsecs; | |
101 | ||
1c5745aa TG |
102 | WARN_ON(timekeeping_suspended); |
103 | ||
8524070b JS |
104 | do { |
105 | seq = read_seqbegin(&xtime_lock); | |
106 | ||
107 | *ts = xtime; | |
9a055117 RZ |
108 | |
109 | /* read clocksource: */ | |
110 | cycle_now = clocksource_read(clock); | |
111 | ||
112 | /* calculate the delta since the last update_wall_time: */ | |
113 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
114 | ||
115 | /* convert to nanoseconds: */ | |
116 | nsecs = cyc2ns(clock, cycle_delta); | |
8524070b | 117 | |
7d27558c JS |
118 | /* If arch requires, add in gettimeoffset() */ |
119 | nsecs += arch_gettimeoffset(); | |
120 | ||
8524070b JS |
121 | } while (read_seqretry(&xtime_lock, seq)); |
122 | ||
123 | timespec_add_ns(ts, nsecs); | |
124 | } | |
125 | ||
8524070b JS |
126 | EXPORT_SYMBOL(getnstimeofday); |
127 | ||
128 | /** | |
129 | * do_gettimeofday - Returns the time of day in a timeval | |
130 | * @tv: pointer to the timeval to be set | |
131 | * | |
efd9ac86 | 132 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b JS |
133 | */ |
134 | void do_gettimeofday(struct timeval *tv) | |
135 | { | |
136 | struct timespec now; | |
137 | ||
efd9ac86 | 138 | getnstimeofday(&now); |
8524070b JS |
139 | tv->tv_sec = now.tv_sec; |
140 | tv->tv_usec = now.tv_nsec/1000; | |
141 | } | |
142 | ||
143 | EXPORT_SYMBOL(do_gettimeofday); | |
144 | /** | |
145 | * do_settimeofday - Sets the time of day | |
146 | * @tv: pointer to the timespec variable containing the new time | |
147 | * | |
148 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
149 | */ | |
150 | int do_settimeofday(struct timespec *tv) | |
151 | { | |
9a055117 | 152 | struct timespec ts_delta; |
8524070b | 153 | unsigned long flags; |
8524070b JS |
154 | |
155 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
156 | return -EINVAL; | |
157 | ||
158 | write_seqlock_irqsave(&xtime_lock, flags); | |
159 | ||
9a055117 RZ |
160 | clocksource_forward_now(); |
161 | ||
162 | ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec; | |
163 | ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec; | |
164 | wall_to_monotonic = timespec_sub(wall_to_monotonic, ts_delta); | |
8524070b | 165 | |
9a055117 | 166 | xtime = *tv; |
8524070b | 167 | |
1001d0a9 | 168 | update_xtime_cache(0); |
8524070b JS |
169 | |
170 | clock->error = 0; | |
171 | ntp_clear(); | |
172 | ||
173 | update_vsyscall(&xtime, clock); | |
174 | ||
175 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
176 | ||
177 | /* signal hrtimers about time change */ | |
178 | clock_was_set(); | |
179 | ||
180 | return 0; | |
181 | } | |
182 | ||
183 | EXPORT_SYMBOL(do_settimeofday); | |
184 | ||
185 | /** | |
186 | * change_clocksource - Swaps clocksources if a new one is available | |
187 | * | |
188 | * Accumulates current time interval and initializes new clocksource | |
189 | */ | |
190 | static void change_clocksource(void) | |
191 | { | |
4614e6ad | 192 | struct clocksource *new, *old; |
8524070b JS |
193 | |
194 | new = clocksource_get_next(); | |
195 | ||
196 | if (clock == new) | |
197 | return; | |
198 | ||
9a055117 | 199 | clocksource_forward_now(); |
8524070b | 200 | |
4614e6ad MD |
201 | if (clocksource_enable(new)) |
202 | return; | |
2d42244a | 203 | |
4614e6ad MD |
204 | new->raw_time = clock->raw_time; |
205 | old = clock; | |
8524070b | 206 | clock = new; |
4614e6ad MD |
207 | clocksource_disable(old); |
208 | ||
9a055117 | 209 | clock->cycle_last = 0; |
4614e6ad | 210 | clock->cycle_last = clocksource_read(clock); |
8524070b JS |
211 | clock->error = 0; |
212 | clock->xtime_nsec = 0; | |
10a398d0 | 213 | clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); |
8524070b JS |
214 | |
215 | tick_clock_notify(); | |
216 | ||
92896bd9 LT |
217 | /* |
218 | * We're holding xtime lock and waking up klogd would deadlock | |
219 | * us on enqueue. So no printing! | |
8524070b JS |
220 | printk(KERN_INFO "Time: %s clocksource has been installed.\n", |
221 | clock->name); | |
92896bd9 | 222 | */ |
8524070b JS |
223 | } |
224 | #else | |
9a055117 | 225 | static inline void clocksource_forward_now(void) { } |
8524070b JS |
226 | static inline void change_clocksource(void) { } |
227 | #endif | |
228 | ||
2d42244a JS |
229 | /** |
230 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
231 | * @ts: pointer to the timespec to be set | |
232 | * | |
233 | * Returns the raw monotonic time (completely un-modified by ntp) | |
234 | */ | |
235 | void getrawmonotonic(struct timespec *ts) | |
236 | { | |
237 | unsigned long seq; | |
238 | s64 nsecs; | |
239 | cycle_t cycle_now, cycle_delta; | |
240 | ||
241 | do { | |
242 | seq = read_seqbegin(&xtime_lock); | |
243 | ||
244 | /* read clocksource: */ | |
245 | cycle_now = clocksource_read(clock); | |
246 | ||
247 | /* calculate the delta since the last update_wall_time: */ | |
248 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
249 | ||
250 | /* convert to nanoseconds: */ | |
251 | nsecs = ((s64)cycle_delta * clock->mult_orig) >> clock->shift; | |
252 | ||
253 | *ts = clock->raw_time; | |
254 | ||
255 | } while (read_seqretry(&xtime_lock, seq)); | |
256 | ||
257 | timespec_add_ns(ts, nsecs); | |
258 | } | |
259 | EXPORT_SYMBOL(getrawmonotonic); | |
260 | ||
261 | ||
8524070b | 262 | /** |
cf4fc6cb | 263 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 264 | */ |
cf4fc6cb | 265 | int timekeeping_valid_for_hres(void) |
8524070b JS |
266 | { |
267 | unsigned long seq; | |
268 | int ret; | |
269 | ||
270 | do { | |
271 | seq = read_seqbegin(&xtime_lock); | |
272 | ||
273 | ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; | |
274 | ||
275 | } while (read_seqretry(&xtime_lock, seq)); | |
276 | ||
277 | return ret; | |
278 | } | |
279 | ||
280 | /** | |
281 | * read_persistent_clock - Return time in seconds from the persistent clock. | |
282 | * | |
283 | * Weak dummy function for arches that do not yet support it. | |
284 | * Returns seconds from epoch using the battery backed persistent clock. | |
285 | * Returns zero if unsupported. | |
286 | * | |
287 | * XXX - Do be sure to remove it once all arches implement it. | |
288 | */ | |
289 | unsigned long __attribute__((weak)) read_persistent_clock(void) | |
290 | { | |
291 | return 0; | |
292 | } | |
293 | ||
294 | /* | |
295 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
296 | */ | |
297 | void __init timekeeping_init(void) | |
298 | { | |
299 | unsigned long flags; | |
300 | unsigned long sec = read_persistent_clock(); | |
301 | ||
302 | write_seqlock_irqsave(&xtime_lock, flags); | |
303 | ||
7dffa3c6 | 304 | ntp_init(); |
8524070b JS |
305 | |
306 | clock = clocksource_get_next(); | |
4614e6ad | 307 | clocksource_enable(clock); |
10a398d0 | 308 | clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); |
8524070b JS |
309 | clock->cycle_last = clocksource_read(clock); |
310 | ||
311 | xtime.tv_sec = sec; | |
312 | xtime.tv_nsec = 0; | |
313 | set_normalized_timespec(&wall_to_monotonic, | |
314 | -xtime.tv_sec, -xtime.tv_nsec); | |
1001d0a9 | 315 | update_xtime_cache(0); |
7c3f1a57 | 316 | total_sleep_time = 0; |
8524070b JS |
317 | write_sequnlock_irqrestore(&xtime_lock, flags); |
318 | } | |
319 | ||
8524070b JS |
320 | /* time in seconds when suspend began */ |
321 | static unsigned long timekeeping_suspend_time; | |
322 | ||
323 | /** | |
324 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
325 | * @dev: unused | |
326 | * | |
327 | * This is for the generic clocksource timekeeping. | |
328 | * xtime/wall_to_monotonic/jiffies/etc are | |
329 | * still managed by arch specific suspend/resume code. | |
330 | */ | |
331 | static int timekeeping_resume(struct sys_device *dev) | |
332 | { | |
333 | unsigned long flags; | |
334 | unsigned long now = read_persistent_clock(); | |
335 | ||
d10ff3fb TG |
336 | clocksource_resume(); |
337 | ||
8524070b JS |
338 | write_seqlock_irqsave(&xtime_lock, flags); |
339 | ||
340 | if (now && (now > timekeeping_suspend_time)) { | |
341 | unsigned long sleep_length = now - timekeeping_suspend_time; | |
342 | ||
343 | xtime.tv_sec += sleep_length; | |
344 | wall_to_monotonic.tv_sec -= sleep_length; | |
7c3f1a57 | 345 | total_sleep_time += sleep_length; |
8524070b | 346 | } |
1001d0a9 | 347 | update_xtime_cache(0); |
8524070b | 348 | /* re-base the last cycle value */ |
d8bb6f4c | 349 | clock->cycle_last = 0; |
8524070b JS |
350 | clock->cycle_last = clocksource_read(clock); |
351 | clock->error = 0; | |
352 | timekeeping_suspended = 0; | |
353 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
354 | ||
355 | touch_softlockup_watchdog(); | |
356 | ||
357 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); | |
358 | ||
359 | /* Resume hrtimers */ | |
360 | hres_timers_resume(); | |
361 | ||
362 | return 0; | |
363 | } | |
364 | ||
365 | static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) | |
366 | { | |
367 | unsigned long flags; | |
368 | ||
3be90950 TG |
369 | timekeeping_suspend_time = read_persistent_clock(); |
370 | ||
8524070b | 371 | write_seqlock_irqsave(&xtime_lock, flags); |
9a055117 | 372 | clocksource_forward_now(); |
8524070b | 373 | timekeeping_suspended = 1; |
8524070b JS |
374 | write_sequnlock_irqrestore(&xtime_lock, flags); |
375 | ||
376 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
377 | ||
378 | return 0; | |
379 | } | |
380 | ||
381 | /* sysfs resume/suspend bits for timekeeping */ | |
382 | static struct sysdev_class timekeeping_sysclass = { | |
af5ca3f4 | 383 | .name = "timekeeping", |
8524070b JS |
384 | .resume = timekeeping_resume, |
385 | .suspend = timekeeping_suspend, | |
8524070b JS |
386 | }; |
387 | ||
388 | static struct sys_device device_timer = { | |
389 | .id = 0, | |
390 | .cls = &timekeeping_sysclass, | |
391 | }; | |
392 | ||
393 | static int __init timekeeping_init_device(void) | |
394 | { | |
395 | int error = sysdev_class_register(&timekeeping_sysclass); | |
396 | if (!error) | |
397 | error = sysdev_register(&device_timer); | |
398 | return error; | |
399 | } | |
400 | ||
401 | device_initcall(timekeeping_init_device); | |
402 | ||
403 | /* | |
404 | * If the error is already larger, we look ahead even further | |
405 | * to compensate for late or lost adjustments. | |
406 | */ | |
407 | static __always_inline int clocksource_bigadjust(s64 error, s64 *interval, | |
408 | s64 *offset) | |
409 | { | |
410 | s64 tick_error, i; | |
411 | u32 look_ahead, adj; | |
412 | s32 error2, mult; | |
413 | ||
414 | /* | |
415 | * Use the current error value to determine how much to look ahead. | |
416 | * The larger the error the slower we adjust for it to avoid problems | |
417 | * with losing too many ticks, otherwise we would overadjust and | |
418 | * produce an even larger error. The smaller the adjustment the | |
419 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 420 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b JS |
421 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
422 | */ | |
7fc5c784 | 423 | error2 = clock->error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b JS |
424 | error2 = abs(error2); |
425 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
426 | error2 >>= 2; | |
427 | ||
428 | /* | |
429 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
430 | * remove the single look ahead already included in the error. | |
431 | */ | |
8383c423 | 432 | tick_error = tick_length >> (NTP_SCALE_SHIFT - clock->shift + 1); |
8524070b JS |
433 | tick_error -= clock->xtime_interval >> 1; |
434 | error = ((error - tick_error) >> look_ahead) + tick_error; | |
435 | ||
436 | /* Finally calculate the adjustment shift value. */ | |
437 | i = *interval; | |
438 | mult = 1; | |
439 | if (error < 0) { | |
440 | error = -error; | |
441 | *interval = -*interval; | |
442 | *offset = -*offset; | |
443 | mult = -1; | |
444 | } | |
445 | for (adj = 0; error > i; adj++) | |
446 | error >>= 1; | |
447 | ||
448 | *interval <<= adj; | |
449 | *offset <<= adj; | |
450 | return mult << adj; | |
451 | } | |
452 | ||
453 | /* | |
454 | * Adjust the multiplier to reduce the error value, | |
455 | * this is optimized for the most common adjustments of -1,0,1, | |
456 | * for other values we can do a bit more work. | |
457 | */ | |
71120f18 | 458 | static void clocksource_adjust(s64 offset) |
8524070b JS |
459 | { |
460 | s64 error, interval = clock->cycle_interval; | |
461 | int adj; | |
462 | ||
7fc5c784 | 463 | error = clock->error >> (NTP_SCALE_SHIFT - clock->shift - 1); |
8524070b JS |
464 | if (error > interval) { |
465 | error >>= 2; | |
466 | if (likely(error <= interval)) | |
467 | adj = 1; | |
468 | else | |
469 | adj = clocksource_bigadjust(error, &interval, &offset); | |
470 | } else if (error < -interval) { | |
471 | error >>= 2; | |
472 | if (likely(error >= -interval)) { | |
473 | adj = -1; | |
474 | interval = -interval; | |
475 | offset = -offset; | |
476 | } else | |
477 | adj = clocksource_bigadjust(error, &interval, &offset); | |
478 | } else | |
479 | return; | |
480 | ||
481 | clock->mult += adj; | |
482 | clock->xtime_interval += interval; | |
483 | clock->xtime_nsec -= offset; | |
484 | clock->error -= (interval - offset) << | |
7fc5c784 | 485 | (NTP_SCALE_SHIFT - clock->shift); |
8524070b JS |
486 | } |
487 | ||
488 | /** | |
489 | * update_wall_time - Uses the current clocksource to increment the wall time | |
490 | * | |
491 | * Called from the timer interrupt, must hold a write on xtime_lock. | |
492 | */ | |
493 | void update_wall_time(void) | |
494 | { | |
495 | cycle_t offset; | |
496 | ||
497 | /* Make sure we're fully resumed: */ | |
498 | if (unlikely(timekeeping_suspended)) | |
499 | return; | |
500 | ||
501 | #ifdef CONFIG_GENERIC_TIME | |
502 | offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask; | |
503 | #else | |
504 | offset = clock->cycle_interval; | |
505 | #endif | |
5cd1c9c5 | 506 | clock->xtime_nsec = (s64)xtime.tv_nsec << clock->shift; |
8524070b JS |
507 | |
508 | /* normally this loop will run just once, however in the | |
509 | * case of lost or late ticks, it will accumulate correctly. | |
510 | */ | |
511 | while (offset >= clock->cycle_interval) { | |
512 | /* accumulate one interval */ | |
8524070b | 513 | offset -= clock->cycle_interval; |
9a055117 | 514 | clock->cycle_last += clock->cycle_interval; |
8524070b | 515 | |
9a055117 | 516 | clock->xtime_nsec += clock->xtime_interval; |
8524070b JS |
517 | if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) { |
518 | clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift; | |
519 | xtime.tv_sec++; | |
520 | second_overflow(); | |
521 | } | |
522 | ||
2d42244a JS |
523 | clock->raw_time.tv_nsec += clock->raw_interval; |
524 | if (clock->raw_time.tv_nsec >= NSEC_PER_SEC) { | |
525 | clock->raw_time.tv_nsec -= NSEC_PER_SEC; | |
526 | clock->raw_time.tv_sec++; | |
527 | } | |
528 | ||
8524070b | 529 | /* accumulate error between NTP and clock interval */ |
8383c423 | 530 | clock->error += tick_length; |
7fc5c784 | 531 | clock->error -= clock->xtime_interval << (NTP_SCALE_SHIFT - clock->shift); |
8524070b JS |
532 | } |
533 | ||
534 | /* correct the clock when NTP error is too big */ | |
71120f18 | 535 | clocksource_adjust(offset); |
8524070b | 536 | |
6c9bacb4 JS |
537 | /* |
538 | * Since in the loop above, we accumulate any amount of time | |
539 | * in xtime_nsec over a second into xtime.tv_sec, its possible for | |
540 | * xtime_nsec to be fairly small after the loop. Further, if we're | |
541 | * slightly speeding the clocksource up in clocksource_adjust(), | |
542 | * its possible the required corrective factor to xtime_nsec could | |
543 | * cause it to underflow. | |
544 | * | |
545 | * Now, we cannot simply roll the accumulated second back, since | |
546 | * the NTP subsystem has been notified via second_overflow. So | |
547 | * instead we push xtime_nsec forward by the amount we underflowed, | |
548 | * and add that amount into the error. | |
549 | * | |
550 | * We'll correct this error next time through this function, when | |
551 | * xtime_nsec is not as small. | |
552 | */ | |
553 | if (unlikely((s64)clock->xtime_nsec < 0)) { | |
554 | s64 neg = -(s64)clock->xtime_nsec; | |
555 | clock->xtime_nsec = 0; | |
556 | clock->error += neg << (NTP_SCALE_SHIFT - clock->shift); | |
557 | } | |
558 | ||
5cd1c9c5 RZ |
559 | /* store full nanoseconds into xtime after rounding it up and |
560 | * add the remainder to the error difference. | |
561 | */ | |
562 | xtime.tv_nsec = ((s64)clock->xtime_nsec >> clock->shift) + 1; | |
8524070b | 563 | clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift; |
5cd1c9c5 | 564 | clock->error += clock->xtime_nsec << (NTP_SCALE_SHIFT - clock->shift); |
8524070b | 565 | |
17c38b74 JS |
566 | update_xtime_cache(cyc2ns(clock, offset)); |
567 | ||
8524070b JS |
568 | /* check to see if there is a new clocksource to use */ |
569 | change_clocksource(); | |
570 | update_vsyscall(&xtime, clock); | |
571 | } | |
7c3f1a57 TJ |
572 | |
573 | /** | |
574 | * getboottime - Return the real time of system boot. | |
575 | * @ts: pointer to the timespec to be set | |
576 | * | |
577 | * Returns the time of day in a timespec. | |
578 | * | |
579 | * This is based on the wall_to_monotonic offset and the total suspend | |
580 | * time. Calls to settimeofday will affect the value returned (which | |
581 | * basically means that however wrong your real time clock is at boot time, | |
582 | * you get the right time here). | |
583 | */ | |
584 | void getboottime(struct timespec *ts) | |
585 | { | |
586 | set_normalized_timespec(ts, | |
587 | - (wall_to_monotonic.tv_sec + total_sleep_time), | |
588 | - wall_to_monotonic.tv_nsec); | |
589 | } | |
590 | ||
591 | /** | |
592 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
593 | * @ts: pointer to the timespec to be converted | |
594 | */ | |
595 | void monotonic_to_bootbased(struct timespec *ts) | |
596 | { | |
597 | ts->tv_sec += total_sleep_time; | |
598 | } | |
2c6b47de | 599 | |
17c38b74 JS |
600 | unsigned long get_seconds(void) |
601 | { | |
602 | return xtime_cache.tv_sec; | |
603 | } | |
604 | EXPORT_SYMBOL(get_seconds); | |
605 | ||
606 | ||
2c6b47de JS |
607 | struct timespec current_kernel_time(void) |
608 | { | |
609 | struct timespec now; | |
610 | unsigned long seq; | |
611 | ||
612 | do { | |
613 | seq = read_seqbegin(&xtime_lock); | |
614 | ||
17c38b74 | 615 | now = xtime_cache; |
2c6b47de JS |
616 | } while (read_seqretry(&xtime_lock, seq)); |
617 | ||
618 | return now; | |
619 | } | |
2c6b47de | 620 | EXPORT_SYMBOL(current_kernel_time); |