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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> | |
d43c36dc | 16 | #include <linux/sched.h> |
e1a85b2c | 17 | #include <linux/syscore_ops.h> |
8524070b JS |
18 | #include <linux/clocksource.h> |
19 | #include <linux/jiffies.h> | |
20 | #include <linux/time.h> | |
21 | #include <linux/tick.h> | |
75c5158f | 22 | #include <linux/stop_machine.h> |
8524070b | 23 | |
155ec602 MS |
24 | /* Structure holding internal timekeeping values. */ |
25 | struct timekeeper { | |
26 | /* Current clocksource used for timekeeping. */ | |
27 | struct clocksource *clock; | |
23ce7211 MS |
28 | /* The shift value of the current clocksource. */ |
29 | int shift; | |
155ec602 MS |
30 | |
31 | /* Number of clock cycles in one NTP interval. */ | |
32 | cycle_t cycle_interval; | |
33 | /* Number of clock shifted nano seconds in one NTP interval. */ | |
34 | u64 xtime_interval; | |
a386b5af KP |
35 | /* shifted nano seconds left over when rounding cycle_interval */ |
36 | s64 xtime_remainder; | |
155ec602 MS |
37 | /* Raw nano seconds accumulated per NTP interval. */ |
38 | u32 raw_interval; | |
39 | ||
40 | /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */ | |
41 | u64 xtime_nsec; | |
42 | /* Difference between accumulated time and NTP time in ntp | |
43 | * shifted nano seconds. */ | |
44 | s64 ntp_error; | |
23ce7211 MS |
45 | /* Shift conversion between clock shifted nano seconds and |
46 | * ntp shifted nano seconds. */ | |
47 | int ntp_error_shift; | |
0a544198 MS |
48 | /* NTP adjusted clock multiplier */ |
49 | u32 mult; | |
00c5fb77 | 50 | |
8ff2cb92 JS |
51 | /* The current time */ |
52 | struct timespec xtime; | |
d9f7217a JS |
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; | |
00c5fb77 JS |
68 | /* time spent in suspend */ |
69 | struct timespec total_sleep_time; | |
01f71b47 JS |
70 | /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */ |
71 | struct timespec raw_time; | |
155ec602 MS |
72 | }; |
73 | ||
afa14e7c | 74 | static struct timekeeper timekeeper; |
155ec602 | 75 | |
8fcce546 JS |
76 | /* |
77 | * This read-write spinlock protects us from races in SMP while | |
78 | * playing with xtime. | |
79 | */ | |
80 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); | |
81 | ||
82 | ||
83 | /* flag for if timekeeping is suspended */ | |
84 | int __read_mostly timekeeping_suspended; | |
85 | ||
86 | ||
87 | ||
155ec602 MS |
88 | /** |
89 | * timekeeper_setup_internals - Set up internals to use clocksource clock. | |
90 | * | |
91 | * @clock: Pointer to clocksource. | |
92 | * | |
93 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment | |
94 | * pair and interval request. | |
95 | * | |
96 | * Unless you're the timekeeping code, you should not be using this! | |
97 | */ | |
98 | static void timekeeper_setup_internals(struct clocksource *clock) | |
99 | { | |
100 | cycle_t interval; | |
a386b5af | 101 | u64 tmp, ntpinterval; |
155ec602 MS |
102 | |
103 | timekeeper.clock = clock; | |
104 | clock->cycle_last = clock->read(clock); | |
105 | ||
106 | /* Do the ns -> cycle conversion first, using original mult */ | |
107 | tmp = NTP_INTERVAL_LENGTH; | |
108 | tmp <<= clock->shift; | |
a386b5af | 109 | ntpinterval = tmp; |
0a544198 MS |
110 | tmp += clock->mult/2; |
111 | do_div(tmp, clock->mult); | |
155ec602 MS |
112 | if (tmp == 0) |
113 | tmp = 1; | |
114 | ||
115 | interval = (cycle_t) tmp; | |
116 | timekeeper.cycle_interval = interval; | |
117 | ||
118 | /* Go back from cycles -> shifted ns */ | |
119 | timekeeper.xtime_interval = (u64) interval * clock->mult; | |
a386b5af | 120 | timekeeper.xtime_remainder = ntpinterval - timekeeper.xtime_interval; |
155ec602 | 121 | timekeeper.raw_interval = |
0a544198 | 122 | ((u64) interval * clock->mult) >> clock->shift; |
155ec602 MS |
123 | |
124 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 125 | timekeeper.shift = clock->shift; |
155ec602 MS |
126 | |
127 | timekeeper.ntp_error = 0; | |
23ce7211 | 128 | timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
0a544198 MS |
129 | |
130 | /* | |
131 | * The timekeeper keeps its own mult values for the currently | |
132 | * active clocksource. These value will be adjusted via NTP | |
133 | * to counteract clock drifting. | |
134 | */ | |
135 | timekeeper.mult = clock->mult; | |
155ec602 | 136 | } |
8524070b | 137 | |
2ba2a305 MS |
138 | /* Timekeeper helper functions. */ |
139 | static inline s64 timekeeping_get_ns(void) | |
140 | { | |
141 | cycle_t cycle_now, cycle_delta; | |
142 | struct clocksource *clock; | |
143 | ||
144 | /* read clocksource: */ | |
145 | clock = timekeeper.clock; | |
146 | cycle_now = clock->read(clock); | |
147 | ||
148 | /* calculate the delta since the last update_wall_time: */ | |
149 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
150 | ||
151 | /* return delta convert to nanoseconds using ntp adjusted mult. */ | |
152 | return clocksource_cyc2ns(cycle_delta, timekeeper.mult, | |
153 | timekeeper.shift); | |
154 | } | |
155 | ||
156 | static inline s64 timekeeping_get_ns_raw(void) | |
157 | { | |
158 | cycle_t cycle_now, cycle_delta; | |
159 | struct clocksource *clock; | |
160 | ||
161 | /* read clocksource: */ | |
162 | clock = timekeeper.clock; | |
163 | cycle_now = clock->read(clock); | |
164 | ||
165 | /* calculate the delta since the last update_wall_time: */ | |
166 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
167 | ||
c9fad429 | 168 | /* return delta convert to nanoseconds. */ |
2ba2a305 MS |
169 | return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
170 | } | |
171 | ||
31089c13 JS |
172 | /* must hold xtime_lock */ |
173 | void timekeeping_leap_insert(int leapsecond) | |
174 | { | |
8ff2cb92 | 175 | timekeeper.xtime.tv_sec += leapsecond; |
d9f7217a | 176 | timekeeper.wall_to_monotonic.tv_sec -= leapsecond; |
8ff2cb92 JS |
177 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
178 | timekeeper.clock, timekeeper.mult); | |
31089c13 | 179 | } |
8524070b | 180 | |
8524070b | 181 | /** |
155ec602 | 182 | * timekeeping_forward_now - update clock to the current time |
8524070b | 183 | * |
9a055117 RZ |
184 | * Forward the current clock to update its state since the last call to |
185 | * update_wall_time(). This is useful before significant clock changes, | |
186 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 187 | */ |
155ec602 | 188 | static void timekeeping_forward_now(void) |
8524070b JS |
189 | { |
190 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 191 | struct clocksource *clock; |
9a055117 | 192 | s64 nsec; |
8524070b | 193 | |
155ec602 | 194 | clock = timekeeper.clock; |
a0f7d48b | 195 | cycle_now = clock->read(clock); |
8524070b | 196 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 197 | clock->cycle_last = cycle_now; |
8524070b | 198 | |
0a544198 MS |
199 | nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
200 | timekeeper.shift); | |
7d27558c JS |
201 | |
202 | /* If arch requires, add in gettimeoffset() */ | |
203 | nsec += arch_gettimeoffset(); | |
204 | ||
8ff2cb92 | 205 | timespec_add_ns(&timekeeper.xtime, nsec); |
2d42244a | 206 | |
0a544198 | 207 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
01f71b47 | 208 | timespec_add_ns(&timekeeper.raw_time, nsec); |
8524070b JS |
209 | } |
210 | ||
211 | /** | |
efd9ac86 | 212 | * getnstimeofday - Returns the time of day in a timespec |
8524070b JS |
213 | * @ts: pointer to the timespec to be set |
214 | * | |
efd9ac86 | 215 | * Returns the time of day in a timespec. |
8524070b | 216 | */ |
efd9ac86 | 217 | void getnstimeofday(struct timespec *ts) |
8524070b JS |
218 | { |
219 | unsigned long seq; | |
220 | s64 nsecs; | |
221 | ||
1c5745aa TG |
222 | WARN_ON(timekeeping_suspended); |
223 | ||
8524070b JS |
224 | do { |
225 | seq = read_seqbegin(&xtime_lock); | |
226 | ||
8ff2cb92 | 227 | *ts = timekeeper.xtime; |
2ba2a305 | 228 | nsecs = timekeeping_get_ns(); |
8524070b | 229 | |
7d27558c JS |
230 | /* If arch requires, add in gettimeoffset() */ |
231 | nsecs += arch_gettimeoffset(); | |
232 | ||
8524070b JS |
233 | } while (read_seqretry(&xtime_lock, seq)); |
234 | ||
235 | timespec_add_ns(ts, nsecs); | |
236 | } | |
237 | ||
8524070b JS |
238 | EXPORT_SYMBOL(getnstimeofday); |
239 | ||
951ed4d3 MS |
240 | ktime_t ktime_get(void) |
241 | { | |
951ed4d3 MS |
242 | unsigned int seq; |
243 | s64 secs, nsecs; | |
244 | ||
245 | WARN_ON(timekeeping_suspended); | |
246 | ||
247 | do { | |
248 | seq = read_seqbegin(&xtime_lock); | |
8ff2cb92 JS |
249 | secs = timekeeper.xtime.tv_sec + |
250 | timekeeper.wall_to_monotonic.tv_sec; | |
251 | nsecs = timekeeper.xtime.tv_nsec + | |
252 | timekeeper.wall_to_monotonic.tv_nsec; | |
2ba2a305 | 253 | nsecs += timekeeping_get_ns(); |
d004e024 HP |
254 | /* If arch requires, add in gettimeoffset() */ |
255 | nsecs += arch_gettimeoffset(); | |
951ed4d3 MS |
256 | |
257 | } while (read_seqretry(&xtime_lock, seq)); | |
258 | /* | |
259 | * Use ktime_set/ktime_add_ns to create a proper ktime on | |
260 | * 32-bit architectures without CONFIG_KTIME_SCALAR. | |
261 | */ | |
262 | return ktime_add_ns(ktime_set(secs, 0), nsecs); | |
263 | } | |
264 | EXPORT_SYMBOL_GPL(ktime_get); | |
265 | ||
266 | /** | |
267 | * ktime_get_ts - get the monotonic clock in timespec format | |
268 | * @ts: pointer to timespec variable | |
269 | * | |
270 | * The function calculates the monotonic clock from the realtime | |
271 | * clock and the wall_to_monotonic offset and stores the result | |
272 | * in normalized timespec format in the variable pointed to by @ts. | |
273 | */ | |
274 | void ktime_get_ts(struct timespec *ts) | |
275 | { | |
951ed4d3 MS |
276 | struct timespec tomono; |
277 | unsigned int seq; | |
278 | s64 nsecs; | |
279 | ||
280 | WARN_ON(timekeeping_suspended); | |
281 | ||
282 | do { | |
283 | seq = read_seqbegin(&xtime_lock); | |
8ff2cb92 | 284 | *ts = timekeeper.xtime; |
d9f7217a | 285 | tomono = timekeeper.wall_to_monotonic; |
2ba2a305 | 286 | nsecs = timekeeping_get_ns(); |
d004e024 HP |
287 | /* If arch requires, add in gettimeoffset() */ |
288 | nsecs += arch_gettimeoffset(); | |
951ed4d3 MS |
289 | |
290 | } while (read_seqretry(&xtime_lock, seq)); | |
291 | ||
292 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
293 | ts->tv_nsec + tomono.tv_nsec + nsecs); | |
294 | } | |
295 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
296 | ||
e2c18e49 AG |
297 | #ifdef CONFIG_NTP_PPS |
298 | ||
299 | /** | |
300 | * getnstime_raw_and_real - get day and raw monotonic time in timespec format | |
301 | * @ts_raw: pointer to the timespec to be set to raw monotonic time | |
302 | * @ts_real: pointer to the timespec to be set to the time of day | |
303 | * | |
304 | * This function reads both the time of day and raw monotonic time at the | |
305 | * same time atomically and stores the resulting timestamps in timespec | |
306 | * format. | |
307 | */ | |
308 | void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) | |
309 | { | |
310 | unsigned long seq; | |
311 | s64 nsecs_raw, nsecs_real; | |
312 | ||
313 | WARN_ON_ONCE(timekeeping_suspended); | |
314 | ||
315 | do { | |
316 | u32 arch_offset; | |
317 | ||
318 | seq = read_seqbegin(&xtime_lock); | |
319 | ||
01f71b47 | 320 | *ts_raw = timekeeper.raw_time; |
8ff2cb92 | 321 | *ts_real = timekeeper.xtime; |
e2c18e49 AG |
322 | |
323 | nsecs_raw = timekeeping_get_ns_raw(); | |
324 | nsecs_real = timekeeping_get_ns(); | |
325 | ||
326 | /* If arch requires, add in gettimeoffset() */ | |
327 | arch_offset = arch_gettimeoffset(); | |
328 | nsecs_raw += arch_offset; | |
329 | nsecs_real += arch_offset; | |
330 | ||
331 | } while (read_seqretry(&xtime_lock, seq)); | |
332 | ||
333 | timespec_add_ns(ts_raw, nsecs_raw); | |
334 | timespec_add_ns(ts_real, nsecs_real); | |
335 | } | |
336 | EXPORT_SYMBOL(getnstime_raw_and_real); | |
337 | ||
338 | #endif /* CONFIG_NTP_PPS */ | |
339 | ||
8524070b JS |
340 | /** |
341 | * do_gettimeofday - Returns the time of day in a timeval | |
342 | * @tv: pointer to the timeval to be set | |
343 | * | |
efd9ac86 | 344 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b JS |
345 | */ |
346 | void do_gettimeofday(struct timeval *tv) | |
347 | { | |
348 | struct timespec now; | |
349 | ||
efd9ac86 | 350 | getnstimeofday(&now); |
8524070b JS |
351 | tv->tv_sec = now.tv_sec; |
352 | tv->tv_usec = now.tv_nsec/1000; | |
353 | } | |
354 | ||
355 | EXPORT_SYMBOL(do_gettimeofday); | |
356 | /** | |
357 | * do_settimeofday - Sets the time of day | |
358 | * @tv: pointer to the timespec variable containing the new time | |
359 | * | |
360 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
361 | */ | |
1e6d7679 | 362 | int do_settimeofday(const struct timespec *tv) |
8524070b | 363 | { |
9a055117 | 364 | struct timespec ts_delta; |
8524070b | 365 | unsigned long flags; |
8524070b JS |
366 | |
367 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
368 | return -EINVAL; | |
369 | ||
370 | write_seqlock_irqsave(&xtime_lock, flags); | |
371 | ||
155ec602 | 372 | timekeeping_forward_now(); |
9a055117 | 373 | |
8ff2cb92 JS |
374 | ts_delta.tv_sec = tv->tv_sec - timekeeper.xtime.tv_sec; |
375 | ts_delta.tv_nsec = tv->tv_nsec - timekeeper.xtime.tv_nsec; | |
d9f7217a JS |
376 | timekeeper.wall_to_monotonic = |
377 | timespec_sub(timekeeper.wall_to_monotonic, ts_delta); | |
8524070b | 378 | |
8ff2cb92 | 379 | timekeeper.xtime = *tv; |
8524070b | 380 | |
155ec602 | 381 | timekeeper.ntp_error = 0; |
8524070b JS |
382 | ntp_clear(); |
383 | ||
8ff2cb92 JS |
384 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
385 | timekeeper.clock, timekeeper.mult); | |
8524070b JS |
386 | |
387 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
388 | ||
389 | /* signal hrtimers about time change */ | |
390 | clock_was_set(); | |
391 | ||
392 | return 0; | |
393 | } | |
394 | ||
395 | EXPORT_SYMBOL(do_settimeofday); | |
396 | ||
c528f7c6 JS |
397 | |
398 | /** | |
399 | * timekeeping_inject_offset - Adds or subtracts from the current time. | |
400 | * @tv: pointer to the timespec variable containing the offset | |
401 | * | |
402 | * Adds or subtracts an offset value from the current time. | |
403 | */ | |
404 | int timekeeping_inject_offset(struct timespec *ts) | |
405 | { | |
406 | unsigned long flags; | |
407 | ||
408 | if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) | |
409 | return -EINVAL; | |
410 | ||
411 | write_seqlock_irqsave(&xtime_lock, flags); | |
412 | ||
413 | timekeeping_forward_now(); | |
414 | ||
8ff2cb92 | 415 | timekeeper.xtime = timespec_add(timekeeper.xtime, *ts); |
d9f7217a JS |
416 | timekeeper.wall_to_monotonic = |
417 | timespec_sub(timekeeper.wall_to_monotonic, *ts); | |
c528f7c6 JS |
418 | |
419 | timekeeper.ntp_error = 0; | |
420 | ntp_clear(); | |
421 | ||
8ff2cb92 JS |
422 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
423 | timekeeper.clock, timekeeper.mult); | |
c528f7c6 JS |
424 | |
425 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
426 | ||
427 | /* signal hrtimers about time change */ | |
428 | clock_was_set(); | |
429 | ||
430 | return 0; | |
431 | } | |
432 | EXPORT_SYMBOL(timekeeping_inject_offset); | |
433 | ||
8524070b JS |
434 | /** |
435 | * change_clocksource - Swaps clocksources if a new one is available | |
436 | * | |
437 | * Accumulates current time interval and initializes new clocksource | |
438 | */ | |
75c5158f | 439 | static int change_clocksource(void *data) |
8524070b | 440 | { |
4614e6ad | 441 | struct clocksource *new, *old; |
8524070b | 442 | |
75c5158f | 443 | new = (struct clocksource *) data; |
8524070b | 444 | |
155ec602 | 445 | timekeeping_forward_now(); |
75c5158f MS |
446 | if (!new->enable || new->enable(new) == 0) { |
447 | old = timekeeper.clock; | |
448 | timekeeper_setup_internals(new); | |
449 | if (old->disable) | |
450 | old->disable(old); | |
451 | } | |
452 | return 0; | |
453 | } | |
8524070b | 454 | |
75c5158f MS |
455 | /** |
456 | * timekeeping_notify - Install a new clock source | |
457 | * @clock: pointer to the clock source | |
458 | * | |
459 | * This function is called from clocksource.c after a new, better clock | |
460 | * source has been registered. The caller holds the clocksource_mutex. | |
461 | */ | |
462 | void timekeeping_notify(struct clocksource *clock) | |
463 | { | |
464 | if (timekeeper.clock == clock) | |
4614e6ad | 465 | return; |
75c5158f | 466 | stop_machine(change_clocksource, clock, NULL); |
8524070b | 467 | tick_clock_notify(); |
8524070b | 468 | } |
75c5158f | 469 | |
a40f262c TG |
470 | /** |
471 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
472 | * | |
473 | * returns the time in ktime_t format | |
474 | */ | |
475 | ktime_t ktime_get_real(void) | |
476 | { | |
477 | struct timespec now; | |
478 | ||
479 | getnstimeofday(&now); | |
480 | ||
481 | return timespec_to_ktime(now); | |
482 | } | |
483 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
8524070b | 484 | |
2d42244a JS |
485 | /** |
486 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
487 | * @ts: pointer to the timespec to be set | |
488 | * | |
489 | * Returns the raw monotonic time (completely un-modified by ntp) | |
490 | */ | |
491 | void getrawmonotonic(struct timespec *ts) | |
492 | { | |
493 | unsigned long seq; | |
494 | s64 nsecs; | |
2d42244a JS |
495 | |
496 | do { | |
497 | seq = read_seqbegin(&xtime_lock); | |
2ba2a305 | 498 | nsecs = timekeeping_get_ns_raw(); |
01f71b47 | 499 | *ts = timekeeper.raw_time; |
2d42244a JS |
500 | |
501 | } while (read_seqretry(&xtime_lock, seq)); | |
502 | ||
503 | timespec_add_ns(ts, nsecs); | |
504 | } | |
505 | EXPORT_SYMBOL(getrawmonotonic); | |
506 | ||
507 | ||
8524070b | 508 | /** |
cf4fc6cb | 509 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 510 | */ |
cf4fc6cb | 511 | int timekeeping_valid_for_hres(void) |
8524070b JS |
512 | { |
513 | unsigned long seq; | |
514 | int ret; | |
515 | ||
516 | do { | |
517 | seq = read_seqbegin(&xtime_lock); | |
518 | ||
155ec602 | 519 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
8524070b JS |
520 | |
521 | } while (read_seqretry(&xtime_lock, seq)); | |
522 | ||
523 | return ret; | |
524 | } | |
525 | ||
98962465 JH |
526 | /** |
527 | * timekeeping_max_deferment - Returns max time the clocksource can be deferred | |
528 | * | |
529 | * Caller must observe xtime_lock via read_seqbegin/read_seqretry to | |
530 | * ensure that the clocksource does not change! | |
531 | */ | |
532 | u64 timekeeping_max_deferment(void) | |
533 | { | |
534 | return timekeeper.clock->max_idle_ns; | |
535 | } | |
536 | ||
8524070b | 537 | /** |
d4f587c6 | 538 | * read_persistent_clock - Return time from the persistent clock. |
8524070b JS |
539 | * |
540 | * Weak dummy function for arches that do not yet support it. | |
d4f587c6 MS |
541 | * Reads the time from the battery backed persistent clock. |
542 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
8524070b JS |
543 | * |
544 | * XXX - Do be sure to remove it once all arches implement it. | |
545 | */ | |
d4f587c6 | 546 | void __attribute__((weak)) read_persistent_clock(struct timespec *ts) |
8524070b | 547 | { |
d4f587c6 MS |
548 | ts->tv_sec = 0; |
549 | ts->tv_nsec = 0; | |
8524070b JS |
550 | } |
551 | ||
23970e38 MS |
552 | /** |
553 | * read_boot_clock - Return time of the system start. | |
554 | * | |
555 | * Weak dummy function for arches that do not yet support it. | |
556 | * Function to read the exact time the system has been started. | |
557 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
558 | * | |
559 | * XXX - Do be sure to remove it once all arches implement it. | |
560 | */ | |
561 | void __attribute__((weak)) read_boot_clock(struct timespec *ts) | |
562 | { | |
563 | ts->tv_sec = 0; | |
564 | ts->tv_nsec = 0; | |
565 | } | |
566 | ||
8524070b JS |
567 | /* |
568 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
569 | */ | |
570 | void __init timekeeping_init(void) | |
571 | { | |
155ec602 | 572 | struct clocksource *clock; |
8524070b | 573 | unsigned long flags; |
23970e38 | 574 | struct timespec now, boot; |
d4f587c6 MS |
575 | |
576 | read_persistent_clock(&now); | |
23970e38 | 577 | read_boot_clock(&boot); |
8524070b JS |
578 | |
579 | write_seqlock_irqsave(&xtime_lock, flags); | |
580 | ||
7dffa3c6 | 581 | ntp_init(); |
8524070b | 582 | |
f1b82746 | 583 | clock = clocksource_default_clock(); |
a0f7d48b MS |
584 | if (clock->enable) |
585 | clock->enable(clock); | |
155ec602 | 586 | timekeeper_setup_internals(clock); |
8524070b | 587 | |
8ff2cb92 JS |
588 | timekeeper.xtime.tv_sec = now.tv_sec; |
589 | timekeeper.xtime.tv_nsec = now.tv_nsec; | |
01f71b47 JS |
590 | timekeeper.raw_time.tv_sec = 0; |
591 | timekeeper.raw_time.tv_nsec = 0; | |
23970e38 | 592 | if (boot.tv_sec == 0 && boot.tv_nsec == 0) { |
8ff2cb92 JS |
593 | boot.tv_sec = timekeeper.xtime.tv_sec; |
594 | boot.tv_nsec = timekeeper.xtime.tv_nsec; | |
23970e38 | 595 | } |
d9f7217a | 596 | set_normalized_timespec(&timekeeper.wall_to_monotonic, |
23970e38 | 597 | -boot.tv_sec, -boot.tv_nsec); |
00c5fb77 JS |
598 | timekeeper.total_sleep_time.tv_sec = 0; |
599 | timekeeper.total_sleep_time.tv_nsec = 0; | |
8524070b JS |
600 | write_sequnlock_irqrestore(&xtime_lock, flags); |
601 | } | |
602 | ||
8524070b | 603 | /* time in seconds when suspend began */ |
d4f587c6 | 604 | static struct timespec timekeeping_suspend_time; |
8524070b | 605 | |
304529b1 JS |
606 | /** |
607 | * __timekeeping_inject_sleeptime - Internal function to add sleep interval | |
608 | * @delta: pointer to a timespec delta value | |
609 | * | |
610 | * Takes a timespec offset measuring a suspend interval and properly | |
611 | * adds the sleep offset to the timekeeping variables. | |
612 | */ | |
613 | static void __timekeeping_inject_sleeptime(struct timespec *delta) | |
614 | { | |
cb5de2f8 | 615 | if (!timespec_valid(delta)) { |
cbaa5152 | 616 | printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid " |
cb5de2f8 JS |
617 | "sleep delta value!\n"); |
618 | return; | |
619 | } | |
620 | ||
8ff2cb92 | 621 | timekeeper.xtime = timespec_add(timekeeper.xtime, *delta); |
d9f7217a JS |
622 | timekeeper.wall_to_monotonic = |
623 | timespec_sub(timekeeper.wall_to_monotonic, *delta); | |
00c5fb77 JS |
624 | timekeeper.total_sleep_time = timespec_add( |
625 | timekeeper.total_sleep_time, *delta); | |
304529b1 JS |
626 | } |
627 | ||
628 | ||
629 | /** | |
630 | * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values | |
631 | * @delta: pointer to a timespec delta value | |
632 | * | |
633 | * This hook is for architectures that cannot support read_persistent_clock | |
634 | * because their RTC/persistent clock is only accessible when irqs are enabled. | |
635 | * | |
636 | * This function should only be called by rtc_resume(), and allows | |
637 | * a suspend offset to be injected into the timekeeping values. | |
638 | */ | |
639 | void timekeeping_inject_sleeptime(struct timespec *delta) | |
640 | { | |
641 | unsigned long flags; | |
642 | struct timespec ts; | |
643 | ||
644 | /* Make sure we don't set the clock twice */ | |
645 | read_persistent_clock(&ts); | |
646 | if (!(ts.tv_sec == 0 && ts.tv_nsec == 0)) | |
647 | return; | |
648 | ||
649 | write_seqlock_irqsave(&xtime_lock, flags); | |
650 | timekeeping_forward_now(); | |
651 | ||
652 | __timekeeping_inject_sleeptime(delta); | |
653 | ||
654 | timekeeper.ntp_error = 0; | |
655 | ntp_clear(); | |
8ff2cb92 JS |
656 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
657 | timekeeper.clock, timekeeper.mult); | |
304529b1 JS |
658 | |
659 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
660 | ||
661 | /* signal hrtimers about time change */ | |
662 | clock_was_set(); | |
663 | } | |
664 | ||
665 | ||
8524070b JS |
666 | /** |
667 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
8524070b JS |
668 | * |
669 | * This is for the generic clocksource timekeeping. | |
670 | * xtime/wall_to_monotonic/jiffies/etc are | |
671 | * still managed by arch specific suspend/resume code. | |
672 | */ | |
e1a85b2c | 673 | static void timekeeping_resume(void) |
8524070b JS |
674 | { |
675 | unsigned long flags; | |
d4f587c6 MS |
676 | struct timespec ts; |
677 | ||
678 | read_persistent_clock(&ts); | |
8524070b | 679 | |
d10ff3fb TG |
680 | clocksource_resume(); |
681 | ||
8524070b JS |
682 | write_seqlock_irqsave(&xtime_lock, flags); |
683 | ||
d4f587c6 MS |
684 | if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { |
685 | ts = timespec_sub(ts, timekeeping_suspend_time); | |
304529b1 | 686 | __timekeeping_inject_sleeptime(&ts); |
8524070b JS |
687 | } |
688 | /* re-base the last cycle value */ | |
155ec602 MS |
689 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
690 | timekeeper.ntp_error = 0; | |
8524070b JS |
691 | timekeeping_suspended = 0; |
692 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
693 | ||
694 | touch_softlockup_watchdog(); | |
695 | ||
696 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); | |
697 | ||
698 | /* Resume hrtimers */ | |
b12a03ce | 699 | hrtimers_resume(); |
8524070b JS |
700 | } |
701 | ||
e1a85b2c | 702 | static int timekeeping_suspend(void) |
8524070b JS |
703 | { |
704 | unsigned long flags; | |
cb33217b JS |
705 | struct timespec delta, delta_delta; |
706 | static struct timespec old_delta; | |
8524070b | 707 | |
d4f587c6 | 708 | read_persistent_clock(&timekeeping_suspend_time); |
3be90950 | 709 | |
8524070b | 710 | write_seqlock_irqsave(&xtime_lock, flags); |
155ec602 | 711 | timekeeping_forward_now(); |
8524070b | 712 | timekeeping_suspended = 1; |
cb33217b JS |
713 | |
714 | /* | |
715 | * To avoid drift caused by repeated suspend/resumes, | |
716 | * which each can add ~1 second drift error, | |
717 | * try to compensate so the difference in system time | |
718 | * and persistent_clock time stays close to constant. | |
719 | */ | |
8ff2cb92 | 720 | delta = timespec_sub(timekeeper.xtime, timekeeping_suspend_time); |
cb33217b JS |
721 | delta_delta = timespec_sub(delta, old_delta); |
722 | if (abs(delta_delta.tv_sec) >= 2) { | |
723 | /* | |
724 | * if delta_delta is too large, assume time correction | |
725 | * has occured and set old_delta to the current delta. | |
726 | */ | |
727 | old_delta = delta; | |
728 | } else { | |
729 | /* Otherwise try to adjust old_system to compensate */ | |
730 | timekeeping_suspend_time = | |
731 | timespec_add(timekeeping_suspend_time, delta_delta); | |
732 | } | |
8524070b JS |
733 | write_sequnlock_irqrestore(&xtime_lock, flags); |
734 | ||
735 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
c54a42b1 | 736 | clocksource_suspend(); |
8524070b JS |
737 | |
738 | return 0; | |
739 | } | |
740 | ||
741 | /* sysfs resume/suspend bits for timekeeping */ | |
e1a85b2c | 742 | static struct syscore_ops timekeeping_syscore_ops = { |
8524070b JS |
743 | .resume = timekeeping_resume, |
744 | .suspend = timekeeping_suspend, | |
8524070b JS |
745 | }; |
746 | ||
e1a85b2c | 747 | static int __init timekeeping_init_ops(void) |
8524070b | 748 | { |
e1a85b2c RW |
749 | register_syscore_ops(&timekeeping_syscore_ops); |
750 | return 0; | |
8524070b JS |
751 | } |
752 | ||
e1a85b2c | 753 | device_initcall(timekeeping_init_ops); |
8524070b JS |
754 | |
755 | /* | |
756 | * If the error is already larger, we look ahead even further | |
757 | * to compensate for late or lost adjustments. | |
758 | */ | |
155ec602 | 759 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
8524070b JS |
760 | s64 *offset) |
761 | { | |
762 | s64 tick_error, i; | |
763 | u32 look_ahead, adj; | |
764 | s32 error2, mult; | |
765 | ||
766 | /* | |
767 | * Use the current error value to determine how much to look ahead. | |
768 | * The larger the error the slower we adjust for it to avoid problems | |
769 | * with losing too many ticks, otherwise we would overadjust and | |
770 | * produce an even larger error. The smaller the adjustment the | |
771 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 772 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b JS |
773 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
774 | */ | |
155ec602 | 775 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b JS |
776 | error2 = abs(error2); |
777 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
778 | error2 >>= 2; | |
779 | ||
780 | /* | |
781 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
782 | * remove the single look ahead already included in the error. | |
783 | */ | |
23ce7211 | 784 | tick_error = tick_length >> (timekeeper.ntp_error_shift + 1); |
155ec602 | 785 | tick_error -= timekeeper.xtime_interval >> 1; |
8524070b JS |
786 | error = ((error - tick_error) >> look_ahead) + tick_error; |
787 | ||
788 | /* Finally calculate the adjustment shift value. */ | |
789 | i = *interval; | |
790 | mult = 1; | |
791 | if (error < 0) { | |
792 | error = -error; | |
793 | *interval = -*interval; | |
794 | *offset = -*offset; | |
795 | mult = -1; | |
796 | } | |
797 | for (adj = 0; error > i; adj++) | |
798 | error >>= 1; | |
799 | ||
800 | *interval <<= adj; | |
801 | *offset <<= adj; | |
802 | return mult << adj; | |
803 | } | |
804 | ||
805 | /* | |
806 | * Adjust the multiplier to reduce the error value, | |
807 | * this is optimized for the most common adjustments of -1,0,1, | |
808 | * for other values we can do a bit more work. | |
809 | */ | |
155ec602 | 810 | static void timekeeping_adjust(s64 offset) |
8524070b | 811 | { |
155ec602 | 812 | s64 error, interval = timekeeper.cycle_interval; |
8524070b JS |
813 | int adj; |
814 | ||
c2bc1111 JS |
815 | /* |
816 | * The point of this is to check if the error is greater then half | |
817 | * an interval. | |
818 | * | |
819 | * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs. | |
820 | * | |
821 | * Note we subtract one in the shift, so that error is really error*2. | |
3f86f28f JS |
822 | * This "saves" dividing(shifting) interval twice, but keeps the |
823 | * (error > interval) comparison as still measuring if error is | |
c2bc1111 JS |
824 | * larger then half an interval. |
825 | * | |
3f86f28f | 826 | * Note: It does not "save" on aggravation when reading the code. |
c2bc1111 | 827 | */ |
23ce7211 | 828 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
8524070b | 829 | if (error > interval) { |
c2bc1111 JS |
830 | /* |
831 | * We now divide error by 4(via shift), which checks if | |
832 | * the error is greater then twice the interval. | |
833 | * If it is greater, we need a bigadjust, if its smaller, | |
834 | * we can adjust by 1. | |
835 | */ | |
8524070b | 836 | error >>= 2; |
c2bc1111 JS |
837 | /* |
838 | * XXX - In update_wall_time, we round up to the next | |
839 | * nanosecond, and store the amount rounded up into | |
840 | * the error. This causes the likely below to be unlikely. | |
841 | * | |
3f86f28f | 842 | * The proper fix is to avoid rounding up by using |
c2bc1111 JS |
843 | * the high precision timekeeper.xtime_nsec instead of |
844 | * xtime.tv_nsec everywhere. Fixing this will take some | |
845 | * time. | |
846 | */ | |
8524070b JS |
847 | if (likely(error <= interval)) |
848 | adj = 1; | |
849 | else | |
155ec602 | 850 | adj = timekeeping_bigadjust(error, &interval, &offset); |
8524070b | 851 | } else if (error < -interval) { |
c2bc1111 | 852 | /* See comment above, this is just switched for the negative */ |
8524070b JS |
853 | error >>= 2; |
854 | if (likely(error >= -interval)) { | |
855 | adj = -1; | |
856 | interval = -interval; | |
857 | offset = -offset; | |
858 | } else | |
155ec602 | 859 | adj = timekeeping_bigadjust(error, &interval, &offset); |
c2bc1111 | 860 | } else /* No adjustment needed */ |
8524070b JS |
861 | return; |
862 | ||
d65670a7 JS |
863 | WARN_ONCE(timekeeper.clock->maxadj && |
864 | (timekeeper.mult + adj > timekeeper.clock->mult + | |
865 | timekeeper.clock->maxadj), | |
866 | "Adjusting %s more then 11%% (%ld vs %ld)\n", | |
867 | timekeeper.clock->name, (long)timekeeper.mult + adj, | |
868 | (long)timekeeper.clock->mult + | |
869 | timekeeper.clock->maxadj); | |
c2bc1111 JS |
870 | /* |
871 | * So the following can be confusing. | |
872 | * | |
873 | * To keep things simple, lets assume adj == 1 for now. | |
874 | * | |
875 | * When adj != 1, remember that the interval and offset values | |
876 | * have been appropriately scaled so the math is the same. | |
877 | * | |
878 | * The basic idea here is that we're increasing the multiplier | |
879 | * by one, this causes the xtime_interval to be incremented by | |
880 | * one cycle_interval. This is because: | |
881 | * xtime_interval = cycle_interval * mult | |
882 | * So if mult is being incremented by one: | |
883 | * xtime_interval = cycle_interval * (mult + 1) | |
884 | * Its the same as: | |
885 | * xtime_interval = (cycle_interval * mult) + cycle_interval | |
886 | * Which can be shortened to: | |
887 | * xtime_interval += cycle_interval | |
888 | * | |
889 | * So offset stores the non-accumulated cycles. Thus the current | |
890 | * time (in shifted nanoseconds) is: | |
891 | * now = (offset * adj) + xtime_nsec | |
892 | * Now, even though we're adjusting the clock frequency, we have | |
893 | * to keep time consistent. In other words, we can't jump back | |
894 | * in time, and we also want to avoid jumping forward in time. | |
895 | * | |
896 | * So given the same offset value, we need the time to be the same | |
897 | * both before and after the freq adjustment. | |
898 | * now = (offset * adj_1) + xtime_nsec_1 | |
899 | * now = (offset * adj_2) + xtime_nsec_2 | |
900 | * So: | |
901 | * (offset * adj_1) + xtime_nsec_1 = | |
902 | * (offset * adj_2) + xtime_nsec_2 | |
903 | * And we know: | |
904 | * adj_2 = adj_1 + 1 | |
905 | * So: | |
906 | * (offset * adj_1) + xtime_nsec_1 = | |
907 | * (offset * (adj_1+1)) + xtime_nsec_2 | |
908 | * (offset * adj_1) + xtime_nsec_1 = | |
909 | * (offset * adj_1) + offset + xtime_nsec_2 | |
910 | * Canceling the sides: | |
911 | * xtime_nsec_1 = offset + xtime_nsec_2 | |
912 | * Which gives us: | |
913 | * xtime_nsec_2 = xtime_nsec_1 - offset | |
914 | * Which simplfies to: | |
915 | * xtime_nsec -= offset | |
916 | * | |
917 | * XXX - TODO: Doc ntp_error calculation. | |
918 | */ | |
0a544198 | 919 | timekeeper.mult += adj; |
155ec602 MS |
920 | timekeeper.xtime_interval += interval; |
921 | timekeeper.xtime_nsec -= offset; | |
922 | timekeeper.ntp_error -= (interval - offset) << | |
23ce7211 | 923 | timekeeper.ntp_error_shift; |
8524070b JS |
924 | } |
925 | ||
83f57a11 | 926 | |
a092ff0f JS |
927 | /** |
928 | * logarithmic_accumulation - shifted accumulation of cycles | |
929 | * | |
930 | * This functions accumulates a shifted interval of cycles into | |
931 | * into a shifted interval nanoseconds. Allows for O(log) accumulation | |
932 | * loop. | |
933 | * | |
934 | * Returns the unconsumed cycles. | |
935 | */ | |
936 | static cycle_t logarithmic_accumulation(cycle_t offset, int shift) | |
937 | { | |
938 | u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; | |
deda2e81 | 939 | u64 raw_nsecs; |
a092ff0f JS |
940 | |
941 | /* If the offset is smaller then a shifted interval, do nothing */ | |
942 | if (offset < timekeeper.cycle_interval<<shift) | |
943 | return offset; | |
944 | ||
945 | /* Accumulate one shifted interval */ | |
946 | offset -= timekeeper.cycle_interval << shift; | |
947 | timekeeper.clock->cycle_last += timekeeper.cycle_interval << shift; | |
948 | ||
949 | timekeeper.xtime_nsec += timekeeper.xtime_interval << shift; | |
950 | while (timekeeper.xtime_nsec >= nsecps) { | |
951 | timekeeper.xtime_nsec -= nsecps; | |
8ff2cb92 | 952 | timekeeper.xtime.tv_sec++; |
a092ff0f JS |
953 | second_overflow(); |
954 | } | |
955 | ||
deda2e81 JW |
956 | /* Accumulate raw time */ |
957 | raw_nsecs = timekeeper.raw_interval << shift; | |
01f71b47 | 958 | raw_nsecs += timekeeper.raw_time.tv_nsec; |
c7dcf87a JS |
959 | if (raw_nsecs >= NSEC_PER_SEC) { |
960 | u64 raw_secs = raw_nsecs; | |
961 | raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); | |
01f71b47 | 962 | timekeeper.raw_time.tv_sec += raw_secs; |
a092ff0f | 963 | } |
01f71b47 | 964 | timekeeper.raw_time.tv_nsec = raw_nsecs; |
a092ff0f JS |
965 | |
966 | /* Accumulate error between NTP and clock interval */ | |
967 | timekeeper.ntp_error += tick_length << shift; | |
a386b5af KP |
968 | timekeeper.ntp_error -= |
969 | (timekeeper.xtime_interval + timekeeper.xtime_remainder) << | |
a092ff0f JS |
970 | (timekeeper.ntp_error_shift + shift); |
971 | ||
972 | return offset; | |
973 | } | |
974 | ||
83f57a11 | 975 | |
8524070b JS |
976 | /** |
977 | * update_wall_time - Uses the current clocksource to increment the wall time | |
978 | * | |
979 | * Called from the timer interrupt, must hold a write on xtime_lock. | |
980 | */ | |
871cf1e5 | 981 | static void update_wall_time(void) |
8524070b | 982 | { |
155ec602 | 983 | struct clocksource *clock; |
8524070b | 984 | cycle_t offset; |
a092ff0f | 985 | int shift = 0, maxshift; |
8524070b JS |
986 | |
987 | /* Make sure we're fully resumed: */ | |
988 | if (unlikely(timekeeping_suspended)) | |
989 | return; | |
990 | ||
155ec602 | 991 | clock = timekeeper.clock; |
592913ec JS |
992 | |
993 | #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET | |
155ec602 | 994 | offset = timekeeper.cycle_interval; |
592913ec JS |
995 | #else |
996 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; | |
8524070b | 997 | #endif |
8ff2cb92 JS |
998 | timekeeper.xtime_nsec = (s64)timekeeper.xtime.tv_nsec << |
999 | timekeeper.shift; | |
8524070b | 1000 | |
a092ff0f JS |
1001 | /* |
1002 | * With NO_HZ we may have to accumulate many cycle_intervals | |
1003 | * (think "ticks") worth of time at once. To do this efficiently, | |
1004 | * we calculate the largest doubling multiple of cycle_intervals | |
1005 | * that is smaller then the offset. We then accumulate that | |
1006 | * chunk in one go, and then try to consume the next smaller | |
1007 | * doubled multiple. | |
8524070b | 1008 | */ |
a092ff0f JS |
1009 | shift = ilog2(offset) - ilog2(timekeeper.cycle_interval); |
1010 | shift = max(0, shift); | |
1011 | /* Bound shift to one less then what overflows tick_length */ | |
1012 | maxshift = (8*sizeof(tick_length) - (ilog2(tick_length)+1)) - 1; | |
1013 | shift = min(shift, maxshift); | |
155ec602 | 1014 | while (offset >= timekeeper.cycle_interval) { |
a092ff0f | 1015 | offset = logarithmic_accumulation(offset, shift); |
830ec045 JS |
1016 | if(offset < timekeeper.cycle_interval<<shift) |
1017 | shift--; | |
8524070b JS |
1018 | } |
1019 | ||
1020 | /* correct the clock when NTP error is too big */ | |
155ec602 | 1021 | timekeeping_adjust(offset); |
8524070b | 1022 | |
6c9bacb4 JS |
1023 | /* |
1024 | * Since in the loop above, we accumulate any amount of time | |
1025 | * in xtime_nsec over a second into xtime.tv_sec, its possible for | |
1026 | * xtime_nsec to be fairly small after the loop. Further, if we're | |
155ec602 | 1027 | * slightly speeding the clocksource up in timekeeping_adjust(), |
6c9bacb4 JS |
1028 | * its possible the required corrective factor to xtime_nsec could |
1029 | * cause it to underflow. | |
1030 | * | |
1031 | * Now, we cannot simply roll the accumulated second back, since | |
1032 | * the NTP subsystem has been notified via second_overflow. So | |
1033 | * instead we push xtime_nsec forward by the amount we underflowed, | |
1034 | * and add that amount into the error. | |
1035 | * | |
1036 | * We'll correct this error next time through this function, when | |
1037 | * xtime_nsec is not as small. | |
1038 | */ | |
155ec602 MS |
1039 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { |
1040 | s64 neg = -(s64)timekeeper.xtime_nsec; | |
1041 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 1042 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; |
6c9bacb4 JS |
1043 | } |
1044 | ||
6a867a39 JS |
1045 | |
1046 | /* | |
1047 | * Store full nanoseconds into xtime after rounding it up and | |
5cd1c9c5 RZ |
1048 | * add the remainder to the error difference. |
1049 | */ | |
8ff2cb92 JS |
1050 | timekeeper.xtime.tv_nsec = ((s64)timekeeper.xtime_nsec >> |
1051 | timekeeper.shift) + 1; | |
1052 | timekeeper.xtime_nsec -= (s64)timekeeper.xtime.tv_nsec << | |
1053 | timekeeper.shift; | |
23ce7211 MS |
1054 | timekeeper.ntp_error += timekeeper.xtime_nsec << |
1055 | timekeeper.ntp_error_shift; | |
8524070b | 1056 | |
6a867a39 JS |
1057 | /* |
1058 | * Finally, make sure that after the rounding | |
1059 | * xtime.tv_nsec isn't larger then NSEC_PER_SEC | |
1060 | */ | |
8ff2cb92 JS |
1061 | if (unlikely(timekeeper.xtime.tv_nsec >= NSEC_PER_SEC)) { |
1062 | timekeeper.xtime.tv_nsec -= NSEC_PER_SEC; | |
1063 | timekeeper.xtime.tv_sec++; | |
6a867a39 JS |
1064 | second_overflow(); |
1065 | } | |
83f57a11 | 1066 | |
8524070b | 1067 | /* check to see if there is a new clocksource to use */ |
8ff2cb92 JS |
1068 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
1069 | timekeeper.clock, timekeeper.mult); | |
8524070b | 1070 | } |
7c3f1a57 TJ |
1071 | |
1072 | /** | |
1073 | * getboottime - Return the real time of system boot. | |
1074 | * @ts: pointer to the timespec to be set | |
1075 | * | |
abb3a4ea | 1076 | * Returns the wall-time of boot in a timespec. |
7c3f1a57 TJ |
1077 | * |
1078 | * This is based on the wall_to_monotonic offset and the total suspend | |
1079 | * time. Calls to settimeofday will affect the value returned (which | |
1080 | * basically means that however wrong your real time clock is at boot time, | |
1081 | * you get the right time here). | |
1082 | */ | |
1083 | void getboottime(struct timespec *ts) | |
1084 | { | |
36d47481 | 1085 | struct timespec boottime = { |
d9f7217a | 1086 | .tv_sec = timekeeper.wall_to_monotonic.tv_sec + |
00c5fb77 | 1087 | timekeeper.total_sleep_time.tv_sec, |
d9f7217a | 1088 | .tv_nsec = timekeeper.wall_to_monotonic.tv_nsec + |
00c5fb77 | 1089 | timekeeper.total_sleep_time.tv_nsec |
36d47481 | 1090 | }; |
d4f587c6 | 1091 | |
d4f587c6 | 1092 | set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); |
7c3f1a57 | 1093 | } |
c93d89f3 | 1094 | EXPORT_SYMBOL_GPL(getboottime); |
7c3f1a57 | 1095 | |
abb3a4ea JS |
1096 | |
1097 | /** | |
1098 | * get_monotonic_boottime - Returns monotonic time since boot | |
1099 | * @ts: pointer to the timespec to be set | |
1100 | * | |
1101 | * Returns the monotonic time since boot in a timespec. | |
1102 | * | |
1103 | * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also | |
1104 | * includes the time spent in suspend. | |
1105 | */ | |
1106 | void get_monotonic_boottime(struct timespec *ts) | |
1107 | { | |
1108 | struct timespec tomono, sleep; | |
1109 | unsigned int seq; | |
1110 | s64 nsecs; | |
1111 | ||
1112 | WARN_ON(timekeeping_suspended); | |
1113 | ||
1114 | do { | |
1115 | seq = read_seqbegin(&xtime_lock); | |
8ff2cb92 | 1116 | *ts = timekeeper.xtime; |
d9f7217a | 1117 | tomono = timekeeper.wall_to_monotonic; |
00c5fb77 | 1118 | sleep = timekeeper.total_sleep_time; |
abb3a4ea JS |
1119 | nsecs = timekeeping_get_ns(); |
1120 | ||
1121 | } while (read_seqretry(&xtime_lock, seq)); | |
1122 | ||
1123 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec, | |
1124 | ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec + nsecs); | |
1125 | } | |
1126 | EXPORT_SYMBOL_GPL(get_monotonic_boottime); | |
1127 | ||
1128 | /** | |
1129 | * ktime_get_boottime - Returns monotonic time since boot in a ktime | |
1130 | * | |
1131 | * Returns the monotonic time since boot in a ktime | |
1132 | * | |
1133 | * This is similar to CLOCK_MONTONIC/ktime_get, but also | |
1134 | * includes the time spent in suspend. | |
1135 | */ | |
1136 | ktime_t ktime_get_boottime(void) | |
1137 | { | |
1138 | struct timespec ts; | |
1139 | ||
1140 | get_monotonic_boottime(&ts); | |
1141 | return timespec_to_ktime(ts); | |
1142 | } | |
1143 | EXPORT_SYMBOL_GPL(ktime_get_boottime); | |
1144 | ||
7c3f1a57 TJ |
1145 | /** |
1146 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
1147 | * @ts: pointer to the timespec to be converted | |
1148 | */ | |
1149 | void monotonic_to_bootbased(struct timespec *ts) | |
1150 | { | |
00c5fb77 | 1151 | *ts = timespec_add(*ts, timekeeper.total_sleep_time); |
7c3f1a57 | 1152 | } |
c93d89f3 | 1153 | EXPORT_SYMBOL_GPL(monotonic_to_bootbased); |
2c6b47de | 1154 | |
17c38b74 JS |
1155 | unsigned long get_seconds(void) |
1156 | { | |
8ff2cb92 | 1157 | return timekeeper.xtime.tv_sec; |
17c38b74 JS |
1158 | } |
1159 | EXPORT_SYMBOL(get_seconds); | |
1160 | ||
da15cfda JS |
1161 | struct timespec __current_kernel_time(void) |
1162 | { | |
8ff2cb92 | 1163 | return timekeeper.xtime; |
da15cfda | 1164 | } |
17c38b74 | 1165 | |
2c6b47de JS |
1166 | struct timespec current_kernel_time(void) |
1167 | { | |
1168 | struct timespec now; | |
1169 | unsigned long seq; | |
1170 | ||
1171 | do { | |
1172 | seq = read_seqbegin(&xtime_lock); | |
83f57a11 | 1173 | |
8ff2cb92 | 1174 | now = timekeeper.xtime; |
2c6b47de JS |
1175 | } while (read_seqretry(&xtime_lock, seq)); |
1176 | ||
1177 | return now; | |
1178 | } | |
2c6b47de | 1179 | EXPORT_SYMBOL(current_kernel_time); |
da15cfda JS |
1180 | |
1181 | struct timespec get_monotonic_coarse(void) | |
1182 | { | |
1183 | struct timespec now, mono; | |
1184 | unsigned long seq; | |
1185 | ||
1186 | do { | |
1187 | seq = read_seqbegin(&xtime_lock); | |
83f57a11 | 1188 | |
8ff2cb92 | 1189 | now = timekeeper.xtime; |
d9f7217a | 1190 | mono = timekeeper.wall_to_monotonic; |
da15cfda JS |
1191 | } while (read_seqretry(&xtime_lock, seq)); |
1192 | ||
1193 | set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, | |
1194 | now.tv_nsec + mono.tv_nsec); | |
1195 | return now; | |
1196 | } | |
871cf1e5 TH |
1197 | |
1198 | /* | |
1199 | * The 64-bit jiffies value is not atomic - you MUST NOT read it | |
1200 | * without sampling the sequence number in xtime_lock. | |
1201 | * jiffies is defined in the linker script... | |
1202 | */ | |
1203 | void do_timer(unsigned long ticks) | |
1204 | { | |
1205 | jiffies_64 += ticks; | |
1206 | update_wall_time(); | |
1207 | calc_global_load(ticks); | |
1208 | } | |
48cf76f7 TH |
1209 | |
1210 | /** | |
314ac371 JS |
1211 | * get_xtime_and_monotonic_and_sleep_offset() - get xtime, wall_to_monotonic, |
1212 | * and sleep offsets. | |
48cf76f7 TH |
1213 | * @xtim: pointer to timespec to be set with xtime |
1214 | * @wtom: pointer to timespec to be set with wall_to_monotonic | |
314ac371 | 1215 | * @sleep: pointer to timespec to be set with time in suspend |
48cf76f7 | 1216 | */ |
314ac371 JS |
1217 | void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, |
1218 | struct timespec *wtom, struct timespec *sleep) | |
48cf76f7 TH |
1219 | { |
1220 | unsigned long seq; | |
1221 | ||
1222 | do { | |
1223 | seq = read_seqbegin(&xtime_lock); | |
8ff2cb92 | 1224 | *xtim = timekeeper.xtime; |
d9f7217a | 1225 | *wtom = timekeeper.wall_to_monotonic; |
00c5fb77 | 1226 | *sleep = timekeeper.total_sleep_time; |
48cf76f7 TH |
1227 | } while (read_seqretry(&xtime_lock, seq)); |
1228 | } | |
f0af911a | 1229 | |
99ee5315 TG |
1230 | /** |
1231 | * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format | |
1232 | */ | |
1233 | ktime_t ktime_get_monotonic_offset(void) | |
1234 | { | |
1235 | unsigned long seq; | |
1236 | struct timespec wtom; | |
1237 | ||
1238 | do { | |
1239 | seq = read_seqbegin(&xtime_lock); | |
d9f7217a | 1240 | wtom = timekeeper.wall_to_monotonic; |
99ee5315 TG |
1241 | } while (read_seqretry(&xtime_lock, seq)); |
1242 | return timespec_to_ktime(wtom); | |
1243 | } | |
1244 | ||
f0af911a TH |
1245 | /** |
1246 | * xtime_update() - advances the timekeeping infrastructure | |
1247 | * @ticks: number of ticks, that have elapsed since the last call. | |
1248 | * | |
1249 | * Must be called with interrupts disabled. | |
1250 | */ | |
1251 | void xtime_update(unsigned long ticks) | |
1252 | { | |
1253 | write_seqlock(&xtime_lock); | |
1254 | do_timer(ticks); | |
1255 | write_sequnlock(&xtime_lock); | |
1256 | } |