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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; | |
058892e6 TG |
28 | /* NTP adjusted clock multiplier */ |
29 | u32 mult; | |
23ce7211 MS |
30 | /* The shift value of the current clocksource. */ |
31 | int shift; | |
155ec602 MS |
32 | |
33 | /* Number of clock cycles in one NTP interval. */ | |
34 | cycle_t cycle_interval; | |
35 | /* Number of clock shifted nano seconds in one NTP interval. */ | |
36 | u64 xtime_interval; | |
a386b5af KP |
37 | /* shifted nano seconds left over when rounding cycle_interval */ |
38 | s64 xtime_remainder; | |
155ec602 MS |
39 | /* Raw nano seconds accumulated per NTP interval. */ |
40 | u32 raw_interval; | |
41 | ||
42 | /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */ | |
43 | u64 xtime_nsec; | |
44 | /* Difference between accumulated time and NTP time in ntp | |
45 | * shifted nano seconds. */ | |
46 | s64 ntp_error; | |
23ce7211 MS |
47 | /* Shift conversion between clock shifted nano seconds and |
48 | * ntp shifted nano seconds. */ | |
49 | int ntp_error_shift; | |
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; | |
70471f2f | 72 | |
5b9fe759 TG |
73 | /* Offset clock monotonic -> clock realtime */ |
74 | ktime_t offs_real; | |
75 | ||
76 | /* Offset clock monotonic -> clock boottime */ | |
77 | ktime_t offs_boot; | |
78 | ||
70471f2f JS |
79 | /* Seqlock for all timekeeper values */ |
80 | seqlock_t lock; | |
155ec602 MS |
81 | }; |
82 | ||
afa14e7c | 83 | static struct timekeeper timekeeper; |
155ec602 | 84 | |
8fcce546 JS |
85 | /* |
86 | * This read-write spinlock protects us from races in SMP while | |
87 | * playing with xtime. | |
88 | */ | |
89 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); | |
90 | ||
91 | ||
92 | /* flag for if timekeeping is suspended */ | |
93 | int __read_mostly timekeeping_suspended; | |
94 | ||
95 | ||
96 | ||
155ec602 MS |
97 | /** |
98 | * timekeeper_setup_internals - Set up internals to use clocksource clock. | |
99 | * | |
100 | * @clock: Pointer to clocksource. | |
101 | * | |
102 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment | |
103 | * pair and interval request. | |
104 | * | |
105 | * Unless you're the timekeeping code, you should not be using this! | |
106 | */ | |
107 | static void timekeeper_setup_internals(struct clocksource *clock) | |
108 | { | |
109 | cycle_t interval; | |
a386b5af | 110 | u64 tmp, ntpinterval; |
155ec602 MS |
111 | |
112 | timekeeper.clock = clock; | |
113 | clock->cycle_last = clock->read(clock); | |
114 | ||
115 | /* Do the ns -> cycle conversion first, using original mult */ | |
116 | tmp = NTP_INTERVAL_LENGTH; | |
117 | tmp <<= clock->shift; | |
a386b5af | 118 | ntpinterval = tmp; |
0a544198 MS |
119 | tmp += clock->mult/2; |
120 | do_div(tmp, clock->mult); | |
155ec602 MS |
121 | if (tmp == 0) |
122 | tmp = 1; | |
123 | ||
124 | interval = (cycle_t) tmp; | |
125 | timekeeper.cycle_interval = interval; | |
126 | ||
127 | /* Go back from cycles -> shifted ns */ | |
128 | timekeeper.xtime_interval = (u64) interval * clock->mult; | |
a386b5af | 129 | timekeeper.xtime_remainder = ntpinterval - timekeeper.xtime_interval; |
155ec602 | 130 | timekeeper.raw_interval = |
0a544198 | 131 | ((u64) interval * clock->mult) >> clock->shift; |
155ec602 MS |
132 | |
133 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 134 | timekeeper.shift = clock->shift; |
155ec602 MS |
135 | |
136 | timekeeper.ntp_error = 0; | |
23ce7211 | 137 | timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
0a544198 MS |
138 | |
139 | /* | |
140 | * The timekeeper keeps its own mult values for the currently | |
141 | * active clocksource. These value will be adjusted via NTP | |
142 | * to counteract clock drifting. | |
143 | */ | |
144 | timekeeper.mult = clock->mult; | |
155ec602 | 145 | } |
8524070b | 146 | |
2ba2a305 MS |
147 | /* Timekeeper helper functions. */ |
148 | static inline s64 timekeeping_get_ns(void) | |
149 | { | |
150 | cycle_t cycle_now, cycle_delta; | |
151 | struct clocksource *clock; | |
152 | ||
153 | /* read clocksource: */ | |
154 | clock = timekeeper.clock; | |
155 | cycle_now = clock->read(clock); | |
156 | ||
157 | /* calculate the delta since the last update_wall_time: */ | |
158 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
159 | ||
160 | /* return delta convert to nanoseconds using ntp adjusted mult. */ | |
161 | return clocksource_cyc2ns(cycle_delta, timekeeper.mult, | |
162 | timekeeper.shift); | |
163 | } | |
164 | ||
165 | static inline s64 timekeeping_get_ns_raw(void) | |
166 | { | |
167 | cycle_t cycle_now, cycle_delta; | |
168 | struct clocksource *clock; | |
169 | ||
170 | /* read clocksource: */ | |
171 | clock = timekeeper.clock; | |
172 | cycle_now = clock->read(clock); | |
173 | ||
174 | /* calculate the delta since the last update_wall_time: */ | |
175 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
176 | ||
c9fad429 | 177 | /* return delta convert to nanoseconds. */ |
2ba2a305 MS |
178 | return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
179 | } | |
180 | ||
5b9fe759 TG |
181 | static void update_rt_offset(void) |
182 | { | |
183 | struct timespec tmp, *wtm = &timekeeper.wall_to_monotonic; | |
184 | ||
185 | set_normalized_timespec(&tmp, -wtm->tv_sec, -wtm->tv_nsec); | |
186 | timekeeper.offs_real = timespec_to_ktime(tmp); | |
187 | } | |
188 | ||
cc06268c TG |
189 | /* must hold write on timekeeper.lock */ |
190 | static void timekeeping_update(bool clearntp) | |
191 | { | |
192 | if (clearntp) { | |
193 | timekeeper.ntp_error = 0; | |
194 | ntp_clear(); | |
195 | } | |
5b9fe759 | 196 | update_rt_offset(); |
cc06268c TG |
197 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
198 | timekeeper.clock, timekeeper.mult); | |
199 | } | |
200 | ||
201 | ||
8524070b | 202 | /** |
155ec602 | 203 | * timekeeping_forward_now - update clock to the current time |
8524070b | 204 | * |
9a055117 RZ |
205 | * Forward the current clock to update its state since the last call to |
206 | * update_wall_time(). This is useful before significant clock changes, | |
207 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 208 | */ |
155ec602 | 209 | static void timekeeping_forward_now(void) |
8524070b JS |
210 | { |
211 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 212 | struct clocksource *clock; |
9a055117 | 213 | s64 nsec; |
8524070b | 214 | |
155ec602 | 215 | clock = timekeeper.clock; |
a0f7d48b | 216 | cycle_now = clock->read(clock); |
8524070b | 217 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 218 | clock->cycle_last = cycle_now; |
8524070b | 219 | |
0a544198 MS |
220 | nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
221 | timekeeper.shift); | |
7d27558c JS |
222 | |
223 | /* If arch requires, add in gettimeoffset() */ | |
224 | nsec += arch_gettimeoffset(); | |
225 | ||
8ff2cb92 | 226 | timespec_add_ns(&timekeeper.xtime, nsec); |
2d42244a | 227 | |
0a544198 | 228 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
01f71b47 | 229 | timespec_add_ns(&timekeeper.raw_time, nsec); |
8524070b JS |
230 | } |
231 | ||
232 | /** | |
efd9ac86 | 233 | * getnstimeofday - Returns the time of day in a timespec |
8524070b JS |
234 | * @ts: pointer to the timespec to be set |
235 | * | |
efd9ac86 | 236 | * Returns the time of day in a timespec. |
8524070b | 237 | */ |
efd9ac86 | 238 | void getnstimeofday(struct timespec *ts) |
8524070b JS |
239 | { |
240 | unsigned long seq; | |
241 | s64 nsecs; | |
242 | ||
1c5745aa TG |
243 | WARN_ON(timekeeping_suspended); |
244 | ||
8524070b | 245 | do { |
70471f2f | 246 | seq = read_seqbegin(&timekeeper.lock); |
8524070b | 247 | |
8ff2cb92 | 248 | *ts = timekeeper.xtime; |
2ba2a305 | 249 | nsecs = timekeeping_get_ns(); |
8524070b | 250 | |
7d27558c JS |
251 | /* If arch requires, add in gettimeoffset() */ |
252 | nsecs += arch_gettimeoffset(); | |
253 | ||
70471f2f | 254 | } while (read_seqretry(&timekeeper.lock, seq)); |
8524070b JS |
255 | |
256 | timespec_add_ns(ts, nsecs); | |
257 | } | |
8524070b JS |
258 | EXPORT_SYMBOL(getnstimeofday); |
259 | ||
951ed4d3 MS |
260 | ktime_t ktime_get(void) |
261 | { | |
951ed4d3 MS |
262 | unsigned int seq; |
263 | s64 secs, nsecs; | |
264 | ||
265 | WARN_ON(timekeeping_suspended); | |
266 | ||
267 | do { | |
70471f2f | 268 | seq = read_seqbegin(&timekeeper.lock); |
8ff2cb92 JS |
269 | secs = timekeeper.xtime.tv_sec + |
270 | timekeeper.wall_to_monotonic.tv_sec; | |
271 | nsecs = timekeeper.xtime.tv_nsec + | |
272 | timekeeper.wall_to_monotonic.tv_nsec; | |
2ba2a305 | 273 | nsecs += timekeeping_get_ns(); |
d004e024 HP |
274 | /* If arch requires, add in gettimeoffset() */ |
275 | nsecs += arch_gettimeoffset(); | |
951ed4d3 | 276 | |
70471f2f | 277 | } while (read_seqretry(&timekeeper.lock, seq)); |
951ed4d3 MS |
278 | /* |
279 | * Use ktime_set/ktime_add_ns to create a proper ktime on | |
280 | * 32-bit architectures without CONFIG_KTIME_SCALAR. | |
281 | */ | |
282 | return ktime_add_ns(ktime_set(secs, 0), nsecs); | |
283 | } | |
284 | EXPORT_SYMBOL_GPL(ktime_get); | |
285 | ||
286 | /** | |
287 | * ktime_get_ts - get the monotonic clock in timespec format | |
288 | * @ts: pointer to timespec variable | |
289 | * | |
290 | * The function calculates the monotonic clock from the realtime | |
291 | * clock and the wall_to_monotonic offset and stores the result | |
292 | * in normalized timespec format in the variable pointed to by @ts. | |
293 | */ | |
294 | void ktime_get_ts(struct timespec *ts) | |
295 | { | |
951ed4d3 MS |
296 | struct timespec tomono; |
297 | unsigned int seq; | |
298 | s64 nsecs; | |
299 | ||
300 | WARN_ON(timekeeping_suspended); | |
301 | ||
302 | do { | |
70471f2f | 303 | seq = read_seqbegin(&timekeeper.lock); |
8ff2cb92 | 304 | *ts = timekeeper.xtime; |
d9f7217a | 305 | tomono = timekeeper.wall_to_monotonic; |
2ba2a305 | 306 | nsecs = timekeeping_get_ns(); |
d004e024 HP |
307 | /* If arch requires, add in gettimeoffset() */ |
308 | nsecs += arch_gettimeoffset(); | |
951ed4d3 | 309 | |
70471f2f | 310 | } while (read_seqretry(&timekeeper.lock, seq)); |
951ed4d3 MS |
311 | |
312 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
313 | ts->tv_nsec + tomono.tv_nsec + nsecs); | |
314 | } | |
315 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
316 | ||
e2c18e49 AG |
317 | #ifdef CONFIG_NTP_PPS |
318 | ||
319 | /** | |
320 | * getnstime_raw_and_real - get day and raw monotonic time in timespec format | |
321 | * @ts_raw: pointer to the timespec to be set to raw monotonic time | |
322 | * @ts_real: pointer to the timespec to be set to the time of day | |
323 | * | |
324 | * This function reads both the time of day and raw monotonic time at the | |
325 | * same time atomically and stores the resulting timestamps in timespec | |
326 | * format. | |
327 | */ | |
328 | void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) | |
329 | { | |
330 | unsigned long seq; | |
331 | s64 nsecs_raw, nsecs_real; | |
332 | ||
333 | WARN_ON_ONCE(timekeeping_suspended); | |
334 | ||
335 | do { | |
336 | u32 arch_offset; | |
337 | ||
70471f2f | 338 | seq = read_seqbegin(&timekeeper.lock); |
e2c18e49 | 339 | |
01f71b47 | 340 | *ts_raw = timekeeper.raw_time; |
8ff2cb92 | 341 | *ts_real = timekeeper.xtime; |
e2c18e49 AG |
342 | |
343 | nsecs_raw = timekeeping_get_ns_raw(); | |
344 | nsecs_real = timekeeping_get_ns(); | |
345 | ||
346 | /* If arch requires, add in gettimeoffset() */ | |
347 | arch_offset = arch_gettimeoffset(); | |
348 | nsecs_raw += arch_offset; | |
349 | nsecs_real += arch_offset; | |
350 | ||
70471f2f | 351 | } while (read_seqretry(&timekeeper.lock, seq)); |
e2c18e49 AG |
352 | |
353 | timespec_add_ns(ts_raw, nsecs_raw); | |
354 | timespec_add_ns(ts_real, nsecs_real); | |
355 | } | |
356 | EXPORT_SYMBOL(getnstime_raw_and_real); | |
357 | ||
358 | #endif /* CONFIG_NTP_PPS */ | |
359 | ||
8524070b JS |
360 | /** |
361 | * do_gettimeofday - Returns the time of day in a timeval | |
362 | * @tv: pointer to the timeval to be set | |
363 | * | |
efd9ac86 | 364 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b JS |
365 | */ |
366 | void do_gettimeofday(struct timeval *tv) | |
367 | { | |
368 | struct timespec now; | |
369 | ||
efd9ac86 | 370 | getnstimeofday(&now); |
8524070b JS |
371 | tv->tv_sec = now.tv_sec; |
372 | tv->tv_usec = now.tv_nsec/1000; | |
373 | } | |
8524070b | 374 | EXPORT_SYMBOL(do_gettimeofday); |
d239f49d | 375 | |
8524070b JS |
376 | /** |
377 | * do_settimeofday - Sets the time of day | |
378 | * @tv: pointer to the timespec variable containing the new time | |
379 | * | |
380 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
381 | */ | |
1e6d7679 | 382 | int do_settimeofday(const struct timespec *tv) |
8524070b | 383 | { |
9a055117 | 384 | struct timespec ts_delta; |
92c1d3ed | 385 | unsigned long flags; |
8524070b JS |
386 | |
387 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
388 | return -EINVAL; | |
389 | ||
92c1d3ed | 390 | write_seqlock_irqsave(&timekeeper.lock, flags); |
8524070b | 391 | |
155ec602 | 392 | timekeeping_forward_now(); |
9a055117 | 393 | |
8ff2cb92 JS |
394 | ts_delta.tv_sec = tv->tv_sec - timekeeper.xtime.tv_sec; |
395 | ts_delta.tv_nsec = tv->tv_nsec - timekeeper.xtime.tv_nsec; | |
d9f7217a JS |
396 | timekeeper.wall_to_monotonic = |
397 | timespec_sub(timekeeper.wall_to_monotonic, ts_delta); | |
8524070b | 398 | |
8ff2cb92 | 399 | timekeeper.xtime = *tv; |
cc06268c | 400 | timekeeping_update(true); |
8524070b | 401 | |
92c1d3ed | 402 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
403 | |
404 | /* signal hrtimers about time change */ | |
405 | clock_was_set(); | |
406 | ||
407 | return 0; | |
408 | } | |
8524070b JS |
409 | EXPORT_SYMBOL(do_settimeofday); |
410 | ||
c528f7c6 JS |
411 | |
412 | /** | |
413 | * timekeeping_inject_offset - Adds or subtracts from the current time. | |
414 | * @tv: pointer to the timespec variable containing the offset | |
415 | * | |
416 | * Adds or subtracts an offset value from the current time. | |
417 | */ | |
418 | int timekeeping_inject_offset(struct timespec *ts) | |
419 | { | |
92c1d3ed | 420 | unsigned long flags; |
c528f7c6 JS |
421 | |
422 | if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) | |
423 | return -EINVAL; | |
424 | ||
92c1d3ed | 425 | write_seqlock_irqsave(&timekeeper.lock, flags); |
c528f7c6 JS |
426 | |
427 | timekeeping_forward_now(); | |
428 | ||
8ff2cb92 | 429 | timekeeper.xtime = timespec_add(timekeeper.xtime, *ts); |
d9f7217a JS |
430 | timekeeper.wall_to_monotonic = |
431 | timespec_sub(timekeeper.wall_to_monotonic, *ts); | |
c528f7c6 | 432 | |
cc06268c | 433 | timekeeping_update(true); |
c528f7c6 | 434 | |
92c1d3ed | 435 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
c528f7c6 JS |
436 | |
437 | /* signal hrtimers about time change */ | |
438 | clock_was_set(); | |
439 | ||
440 | return 0; | |
441 | } | |
442 | EXPORT_SYMBOL(timekeeping_inject_offset); | |
443 | ||
8524070b JS |
444 | /** |
445 | * change_clocksource - Swaps clocksources if a new one is available | |
446 | * | |
447 | * Accumulates current time interval and initializes new clocksource | |
448 | */ | |
75c5158f | 449 | static int change_clocksource(void *data) |
8524070b | 450 | { |
4614e6ad | 451 | struct clocksource *new, *old; |
f695cf94 | 452 | unsigned long flags; |
8524070b | 453 | |
75c5158f | 454 | new = (struct clocksource *) data; |
8524070b | 455 | |
f695cf94 JS |
456 | write_seqlock_irqsave(&timekeeper.lock, flags); |
457 | ||
155ec602 | 458 | timekeeping_forward_now(); |
75c5158f MS |
459 | if (!new->enable || new->enable(new) == 0) { |
460 | old = timekeeper.clock; | |
461 | timekeeper_setup_internals(new); | |
462 | if (old->disable) | |
463 | old->disable(old); | |
464 | } | |
f695cf94 JS |
465 | timekeeping_update(true); |
466 | ||
467 | write_sequnlock_irqrestore(&timekeeper.lock, flags); | |
468 | ||
75c5158f MS |
469 | return 0; |
470 | } | |
8524070b | 471 | |
75c5158f MS |
472 | /** |
473 | * timekeeping_notify - Install a new clock source | |
474 | * @clock: pointer to the clock source | |
475 | * | |
476 | * This function is called from clocksource.c after a new, better clock | |
477 | * source has been registered. The caller holds the clocksource_mutex. | |
478 | */ | |
479 | void timekeeping_notify(struct clocksource *clock) | |
480 | { | |
481 | if (timekeeper.clock == clock) | |
4614e6ad | 482 | return; |
75c5158f | 483 | stop_machine(change_clocksource, clock, NULL); |
8524070b | 484 | tick_clock_notify(); |
8524070b | 485 | } |
75c5158f | 486 | |
a40f262c TG |
487 | /** |
488 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
489 | * | |
490 | * returns the time in ktime_t format | |
491 | */ | |
492 | ktime_t ktime_get_real(void) | |
493 | { | |
494 | struct timespec now; | |
495 | ||
496 | getnstimeofday(&now); | |
497 | ||
498 | return timespec_to_ktime(now); | |
499 | } | |
500 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
8524070b | 501 | |
2d42244a JS |
502 | /** |
503 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
504 | * @ts: pointer to the timespec to be set | |
505 | * | |
506 | * Returns the raw monotonic time (completely un-modified by ntp) | |
507 | */ | |
508 | void getrawmonotonic(struct timespec *ts) | |
509 | { | |
510 | unsigned long seq; | |
511 | s64 nsecs; | |
2d42244a JS |
512 | |
513 | do { | |
70471f2f | 514 | seq = read_seqbegin(&timekeeper.lock); |
2ba2a305 | 515 | nsecs = timekeeping_get_ns_raw(); |
01f71b47 | 516 | *ts = timekeeper.raw_time; |
2d42244a | 517 | |
70471f2f | 518 | } while (read_seqretry(&timekeeper.lock, seq)); |
2d42244a JS |
519 | |
520 | timespec_add_ns(ts, nsecs); | |
521 | } | |
522 | EXPORT_SYMBOL(getrawmonotonic); | |
523 | ||
524 | ||
8524070b | 525 | /** |
cf4fc6cb | 526 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 527 | */ |
cf4fc6cb | 528 | int timekeeping_valid_for_hres(void) |
8524070b JS |
529 | { |
530 | unsigned long seq; | |
531 | int ret; | |
532 | ||
533 | do { | |
70471f2f | 534 | seq = read_seqbegin(&timekeeper.lock); |
8524070b | 535 | |
155ec602 | 536 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
8524070b | 537 | |
70471f2f | 538 | } while (read_seqretry(&timekeeper.lock, seq)); |
8524070b JS |
539 | |
540 | return ret; | |
541 | } | |
542 | ||
98962465 JH |
543 | /** |
544 | * timekeeping_max_deferment - Returns max time the clocksource can be deferred | |
98962465 JH |
545 | */ |
546 | u64 timekeeping_max_deferment(void) | |
547 | { | |
70471f2f JS |
548 | unsigned long seq; |
549 | u64 ret; | |
550 | do { | |
551 | seq = read_seqbegin(&timekeeper.lock); | |
552 | ||
553 | ret = timekeeper.clock->max_idle_ns; | |
554 | ||
555 | } while (read_seqretry(&timekeeper.lock, seq)); | |
556 | ||
557 | return ret; | |
98962465 JH |
558 | } |
559 | ||
8524070b | 560 | /** |
d4f587c6 | 561 | * read_persistent_clock - Return time from the persistent clock. |
8524070b JS |
562 | * |
563 | * Weak dummy function for arches that do not yet support it. | |
d4f587c6 MS |
564 | * Reads the time from the battery backed persistent clock. |
565 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
8524070b JS |
566 | * |
567 | * XXX - Do be sure to remove it once all arches implement it. | |
568 | */ | |
d4f587c6 | 569 | void __attribute__((weak)) read_persistent_clock(struct timespec *ts) |
8524070b | 570 | { |
d4f587c6 MS |
571 | ts->tv_sec = 0; |
572 | ts->tv_nsec = 0; | |
8524070b JS |
573 | } |
574 | ||
23970e38 MS |
575 | /** |
576 | * read_boot_clock - Return time of the system start. | |
577 | * | |
578 | * Weak dummy function for arches that do not yet support it. | |
579 | * Function to read the exact time the system has been started. | |
580 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
581 | * | |
582 | * XXX - Do be sure to remove it once all arches implement it. | |
583 | */ | |
584 | void __attribute__((weak)) read_boot_clock(struct timespec *ts) | |
585 | { | |
586 | ts->tv_sec = 0; | |
587 | ts->tv_nsec = 0; | |
588 | } | |
589 | ||
8524070b JS |
590 | /* |
591 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
592 | */ | |
593 | void __init timekeeping_init(void) | |
594 | { | |
155ec602 | 595 | struct clocksource *clock; |
8524070b | 596 | unsigned long flags; |
23970e38 | 597 | struct timespec now, boot; |
d4f587c6 MS |
598 | |
599 | read_persistent_clock(&now); | |
23970e38 | 600 | read_boot_clock(&boot); |
8524070b | 601 | |
70471f2f | 602 | seqlock_init(&timekeeper.lock); |
8524070b | 603 | |
7dffa3c6 | 604 | ntp_init(); |
8524070b | 605 | |
70471f2f | 606 | write_seqlock_irqsave(&timekeeper.lock, flags); |
f1b82746 | 607 | clock = clocksource_default_clock(); |
a0f7d48b MS |
608 | if (clock->enable) |
609 | clock->enable(clock); | |
155ec602 | 610 | timekeeper_setup_internals(clock); |
8524070b | 611 | |
8ff2cb92 JS |
612 | timekeeper.xtime.tv_sec = now.tv_sec; |
613 | timekeeper.xtime.tv_nsec = now.tv_nsec; | |
01f71b47 JS |
614 | timekeeper.raw_time.tv_sec = 0; |
615 | timekeeper.raw_time.tv_nsec = 0; | |
23970e38 | 616 | if (boot.tv_sec == 0 && boot.tv_nsec == 0) { |
8ff2cb92 JS |
617 | boot.tv_sec = timekeeper.xtime.tv_sec; |
618 | boot.tv_nsec = timekeeper.xtime.tv_nsec; | |
23970e38 | 619 | } |
d9f7217a | 620 | set_normalized_timespec(&timekeeper.wall_to_monotonic, |
23970e38 | 621 | -boot.tv_sec, -boot.tv_nsec); |
5b9fe759 | 622 | update_rt_offset(); |
00c5fb77 JS |
623 | timekeeper.total_sleep_time.tv_sec = 0; |
624 | timekeeper.total_sleep_time.tv_nsec = 0; | |
70471f2f | 625 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
626 | } |
627 | ||
8524070b | 628 | /* time in seconds when suspend began */ |
d4f587c6 | 629 | static struct timespec timekeeping_suspend_time; |
8524070b | 630 | |
5b9fe759 TG |
631 | static void update_sleep_time(struct timespec t) |
632 | { | |
633 | timekeeper.total_sleep_time = t; | |
634 | timekeeper.offs_boot = timespec_to_ktime(t); | |
635 | } | |
636 | ||
304529b1 JS |
637 | /** |
638 | * __timekeeping_inject_sleeptime - Internal function to add sleep interval | |
639 | * @delta: pointer to a timespec delta value | |
640 | * | |
641 | * Takes a timespec offset measuring a suspend interval and properly | |
642 | * adds the sleep offset to the timekeeping variables. | |
643 | */ | |
644 | static void __timekeeping_inject_sleeptime(struct timespec *delta) | |
645 | { | |
cb5de2f8 | 646 | if (!timespec_valid(delta)) { |
cbaa5152 | 647 | printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid " |
cb5de2f8 JS |
648 | "sleep delta value!\n"); |
649 | return; | |
650 | } | |
651 | ||
8ff2cb92 | 652 | timekeeper.xtime = timespec_add(timekeeper.xtime, *delta); |
d9f7217a JS |
653 | timekeeper.wall_to_monotonic = |
654 | timespec_sub(timekeeper.wall_to_monotonic, *delta); | |
5b9fe759 | 655 | update_sleep_time(timespec_add(timekeeper.total_sleep_time, *delta)); |
304529b1 JS |
656 | } |
657 | ||
658 | ||
659 | /** | |
660 | * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values | |
661 | * @delta: pointer to a timespec delta value | |
662 | * | |
663 | * This hook is for architectures that cannot support read_persistent_clock | |
664 | * because their RTC/persistent clock is only accessible when irqs are enabled. | |
665 | * | |
666 | * This function should only be called by rtc_resume(), and allows | |
667 | * a suspend offset to be injected into the timekeeping values. | |
668 | */ | |
669 | void timekeeping_inject_sleeptime(struct timespec *delta) | |
670 | { | |
92c1d3ed | 671 | unsigned long flags; |
304529b1 JS |
672 | struct timespec ts; |
673 | ||
674 | /* Make sure we don't set the clock twice */ | |
675 | read_persistent_clock(&ts); | |
676 | if (!(ts.tv_sec == 0 && ts.tv_nsec == 0)) | |
677 | return; | |
678 | ||
92c1d3ed | 679 | write_seqlock_irqsave(&timekeeper.lock, flags); |
70471f2f | 680 | |
304529b1 JS |
681 | timekeeping_forward_now(); |
682 | ||
683 | __timekeeping_inject_sleeptime(delta); | |
684 | ||
cc06268c | 685 | timekeeping_update(true); |
304529b1 | 686 | |
92c1d3ed | 687 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
304529b1 JS |
688 | |
689 | /* signal hrtimers about time change */ | |
690 | clock_was_set(); | |
691 | } | |
692 | ||
693 | ||
8524070b JS |
694 | /** |
695 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
8524070b JS |
696 | * |
697 | * This is for the generic clocksource timekeeping. | |
698 | * xtime/wall_to_monotonic/jiffies/etc are | |
699 | * still managed by arch specific suspend/resume code. | |
700 | */ | |
e1a85b2c | 701 | static void timekeeping_resume(void) |
8524070b | 702 | { |
92c1d3ed | 703 | unsigned long flags; |
d4f587c6 MS |
704 | struct timespec ts; |
705 | ||
706 | read_persistent_clock(&ts); | |
8524070b | 707 | |
d10ff3fb TG |
708 | clocksource_resume(); |
709 | ||
92c1d3ed | 710 | write_seqlock_irqsave(&timekeeper.lock, flags); |
8524070b | 711 | |
d4f587c6 MS |
712 | if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { |
713 | ts = timespec_sub(ts, timekeeping_suspend_time); | |
304529b1 | 714 | __timekeeping_inject_sleeptime(&ts); |
8524070b JS |
715 | } |
716 | /* re-base the last cycle value */ | |
155ec602 MS |
717 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
718 | timekeeper.ntp_error = 0; | |
8524070b | 719 | timekeeping_suspended = 0; |
92c1d3ed | 720 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
721 | |
722 | touch_softlockup_watchdog(); | |
723 | ||
724 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); | |
725 | ||
726 | /* Resume hrtimers */ | |
b12a03ce | 727 | hrtimers_resume(); |
8524070b JS |
728 | } |
729 | ||
e1a85b2c | 730 | static int timekeeping_suspend(void) |
8524070b | 731 | { |
92c1d3ed | 732 | unsigned long flags; |
cb33217b JS |
733 | struct timespec delta, delta_delta; |
734 | static struct timespec old_delta; | |
8524070b | 735 | |
d4f587c6 | 736 | read_persistent_clock(&timekeeping_suspend_time); |
3be90950 | 737 | |
92c1d3ed | 738 | write_seqlock_irqsave(&timekeeper.lock, flags); |
155ec602 | 739 | timekeeping_forward_now(); |
8524070b | 740 | timekeeping_suspended = 1; |
cb33217b JS |
741 | |
742 | /* | |
743 | * To avoid drift caused by repeated suspend/resumes, | |
744 | * which each can add ~1 second drift error, | |
745 | * try to compensate so the difference in system time | |
746 | * and persistent_clock time stays close to constant. | |
747 | */ | |
8ff2cb92 | 748 | delta = timespec_sub(timekeeper.xtime, timekeeping_suspend_time); |
cb33217b JS |
749 | delta_delta = timespec_sub(delta, old_delta); |
750 | if (abs(delta_delta.tv_sec) >= 2) { | |
751 | /* | |
752 | * if delta_delta is too large, assume time correction | |
753 | * has occured and set old_delta to the current delta. | |
754 | */ | |
755 | old_delta = delta; | |
756 | } else { | |
757 | /* Otherwise try to adjust old_system to compensate */ | |
758 | timekeeping_suspend_time = | |
759 | timespec_add(timekeeping_suspend_time, delta_delta); | |
760 | } | |
92c1d3ed | 761 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
762 | |
763 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
c54a42b1 | 764 | clocksource_suspend(); |
8524070b JS |
765 | |
766 | return 0; | |
767 | } | |
768 | ||
769 | /* sysfs resume/suspend bits for timekeeping */ | |
e1a85b2c | 770 | static struct syscore_ops timekeeping_syscore_ops = { |
8524070b JS |
771 | .resume = timekeeping_resume, |
772 | .suspend = timekeeping_suspend, | |
8524070b JS |
773 | }; |
774 | ||
e1a85b2c | 775 | static int __init timekeeping_init_ops(void) |
8524070b | 776 | { |
e1a85b2c RW |
777 | register_syscore_ops(&timekeeping_syscore_ops); |
778 | return 0; | |
8524070b JS |
779 | } |
780 | ||
e1a85b2c | 781 | device_initcall(timekeeping_init_ops); |
8524070b JS |
782 | |
783 | /* | |
784 | * If the error is already larger, we look ahead even further | |
785 | * to compensate for late or lost adjustments. | |
786 | */ | |
155ec602 | 787 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
8524070b JS |
788 | s64 *offset) |
789 | { | |
790 | s64 tick_error, i; | |
791 | u32 look_ahead, adj; | |
792 | s32 error2, mult; | |
793 | ||
794 | /* | |
795 | * Use the current error value to determine how much to look ahead. | |
796 | * The larger the error the slower we adjust for it to avoid problems | |
797 | * with losing too many ticks, otherwise we would overadjust and | |
798 | * produce an even larger error. The smaller the adjustment the | |
799 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 800 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b JS |
801 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
802 | */ | |
155ec602 | 803 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b JS |
804 | error2 = abs(error2); |
805 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
806 | error2 >>= 2; | |
807 | ||
808 | /* | |
809 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
810 | * remove the single look ahead already included in the error. | |
811 | */ | |
ea7cf49a | 812 | tick_error = ntp_tick_length() >> (timekeeper.ntp_error_shift + 1); |
155ec602 | 813 | tick_error -= timekeeper.xtime_interval >> 1; |
8524070b JS |
814 | error = ((error - tick_error) >> look_ahead) + tick_error; |
815 | ||
816 | /* Finally calculate the adjustment shift value. */ | |
817 | i = *interval; | |
818 | mult = 1; | |
819 | if (error < 0) { | |
820 | error = -error; | |
821 | *interval = -*interval; | |
822 | *offset = -*offset; | |
823 | mult = -1; | |
824 | } | |
825 | for (adj = 0; error > i; adj++) | |
826 | error >>= 1; | |
827 | ||
828 | *interval <<= adj; | |
829 | *offset <<= adj; | |
830 | return mult << adj; | |
831 | } | |
832 | ||
833 | /* | |
834 | * Adjust the multiplier to reduce the error value, | |
835 | * this is optimized for the most common adjustments of -1,0,1, | |
836 | * for other values we can do a bit more work. | |
837 | */ | |
155ec602 | 838 | static void timekeeping_adjust(s64 offset) |
8524070b | 839 | { |
155ec602 | 840 | s64 error, interval = timekeeper.cycle_interval; |
8524070b JS |
841 | int adj; |
842 | ||
c2bc1111 | 843 | /* |
88b28adf | 844 | * The point of this is to check if the error is greater than half |
c2bc1111 JS |
845 | * an interval. |
846 | * | |
847 | * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs. | |
848 | * | |
849 | * Note we subtract one in the shift, so that error is really error*2. | |
3f86f28f JS |
850 | * This "saves" dividing(shifting) interval twice, but keeps the |
851 | * (error > interval) comparison as still measuring if error is | |
88b28adf | 852 | * larger than half an interval. |
c2bc1111 | 853 | * |
3f86f28f | 854 | * Note: It does not "save" on aggravation when reading the code. |
c2bc1111 | 855 | */ |
23ce7211 | 856 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
8524070b | 857 | if (error > interval) { |
c2bc1111 JS |
858 | /* |
859 | * We now divide error by 4(via shift), which checks if | |
88b28adf | 860 | * the error is greater than twice the interval. |
c2bc1111 JS |
861 | * If it is greater, we need a bigadjust, if its smaller, |
862 | * we can adjust by 1. | |
863 | */ | |
8524070b | 864 | error >>= 2; |
c2bc1111 JS |
865 | /* |
866 | * XXX - In update_wall_time, we round up to the next | |
867 | * nanosecond, and store the amount rounded up into | |
868 | * the error. This causes the likely below to be unlikely. | |
869 | * | |
3f86f28f | 870 | * The proper fix is to avoid rounding up by using |
c2bc1111 JS |
871 | * the high precision timekeeper.xtime_nsec instead of |
872 | * xtime.tv_nsec everywhere. Fixing this will take some | |
873 | * time. | |
874 | */ | |
8524070b JS |
875 | if (likely(error <= interval)) |
876 | adj = 1; | |
877 | else | |
155ec602 | 878 | adj = timekeeping_bigadjust(error, &interval, &offset); |
8524070b | 879 | } else if (error < -interval) { |
c2bc1111 | 880 | /* See comment above, this is just switched for the negative */ |
8524070b JS |
881 | error >>= 2; |
882 | if (likely(error >= -interval)) { | |
883 | adj = -1; | |
884 | interval = -interval; | |
885 | offset = -offset; | |
886 | } else | |
155ec602 | 887 | adj = timekeeping_bigadjust(error, &interval, &offset); |
c2bc1111 | 888 | } else /* No adjustment needed */ |
8524070b JS |
889 | return; |
890 | ||
e919cfd4 JS |
891 | if (unlikely(timekeeper.clock->maxadj && |
892 | (timekeeper.mult + adj > | |
893 | timekeeper.clock->mult + timekeeper.clock->maxadj))) { | |
894 | printk_once(KERN_WARNING | |
895 | "Adjusting %s more than 11%% (%ld vs %ld)\n", | |
d65670a7 JS |
896 | timekeeper.clock->name, (long)timekeeper.mult + adj, |
897 | (long)timekeeper.clock->mult + | |
898 | timekeeper.clock->maxadj); | |
e919cfd4 | 899 | } |
c2bc1111 JS |
900 | /* |
901 | * So the following can be confusing. | |
902 | * | |
903 | * To keep things simple, lets assume adj == 1 for now. | |
904 | * | |
905 | * When adj != 1, remember that the interval and offset values | |
906 | * have been appropriately scaled so the math is the same. | |
907 | * | |
908 | * The basic idea here is that we're increasing the multiplier | |
909 | * by one, this causes the xtime_interval to be incremented by | |
910 | * one cycle_interval. This is because: | |
911 | * xtime_interval = cycle_interval * mult | |
912 | * So if mult is being incremented by one: | |
913 | * xtime_interval = cycle_interval * (mult + 1) | |
914 | * Its the same as: | |
915 | * xtime_interval = (cycle_interval * mult) + cycle_interval | |
916 | * Which can be shortened to: | |
917 | * xtime_interval += cycle_interval | |
918 | * | |
919 | * So offset stores the non-accumulated cycles. Thus the current | |
920 | * time (in shifted nanoseconds) is: | |
921 | * now = (offset * adj) + xtime_nsec | |
922 | * Now, even though we're adjusting the clock frequency, we have | |
923 | * to keep time consistent. In other words, we can't jump back | |
924 | * in time, and we also want to avoid jumping forward in time. | |
925 | * | |
926 | * So given the same offset value, we need the time to be the same | |
927 | * both before and after the freq adjustment. | |
928 | * now = (offset * adj_1) + xtime_nsec_1 | |
929 | * now = (offset * adj_2) + xtime_nsec_2 | |
930 | * So: | |
931 | * (offset * adj_1) + xtime_nsec_1 = | |
932 | * (offset * adj_2) + xtime_nsec_2 | |
933 | * And we know: | |
934 | * adj_2 = adj_1 + 1 | |
935 | * So: | |
936 | * (offset * adj_1) + xtime_nsec_1 = | |
937 | * (offset * (adj_1+1)) + xtime_nsec_2 | |
938 | * (offset * adj_1) + xtime_nsec_1 = | |
939 | * (offset * adj_1) + offset + xtime_nsec_2 | |
940 | * Canceling the sides: | |
941 | * xtime_nsec_1 = offset + xtime_nsec_2 | |
942 | * Which gives us: | |
943 | * xtime_nsec_2 = xtime_nsec_1 - offset | |
944 | * Which simplfies to: | |
945 | * xtime_nsec -= offset | |
946 | * | |
947 | * XXX - TODO: Doc ntp_error calculation. | |
948 | */ | |
0a544198 | 949 | timekeeper.mult += adj; |
155ec602 MS |
950 | timekeeper.xtime_interval += interval; |
951 | timekeeper.xtime_nsec -= offset; | |
952 | timekeeper.ntp_error -= (interval - offset) << | |
23ce7211 | 953 | timekeeper.ntp_error_shift; |
8524070b JS |
954 | } |
955 | ||
83f57a11 | 956 | |
a092ff0f JS |
957 | /** |
958 | * logarithmic_accumulation - shifted accumulation of cycles | |
959 | * | |
960 | * This functions accumulates a shifted interval of cycles into | |
961 | * into a shifted interval nanoseconds. Allows for O(log) accumulation | |
962 | * loop. | |
963 | * | |
964 | * Returns the unconsumed cycles. | |
965 | */ | |
966 | static cycle_t logarithmic_accumulation(cycle_t offset, int shift) | |
967 | { | |
968 | u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; | |
deda2e81 | 969 | u64 raw_nsecs; |
a092ff0f | 970 | |
88b28adf | 971 | /* If the offset is smaller than a shifted interval, do nothing */ |
a092ff0f JS |
972 | if (offset < timekeeper.cycle_interval<<shift) |
973 | return offset; | |
974 | ||
975 | /* Accumulate one shifted interval */ | |
976 | offset -= timekeeper.cycle_interval << shift; | |
977 | timekeeper.clock->cycle_last += timekeeper.cycle_interval << shift; | |
978 | ||
979 | timekeeper.xtime_nsec += timekeeper.xtime_interval << shift; | |
980 | while (timekeeper.xtime_nsec >= nsecps) { | |
6b43ae8a | 981 | int leap; |
a092ff0f | 982 | timekeeper.xtime_nsec -= nsecps; |
8ff2cb92 | 983 | timekeeper.xtime.tv_sec++; |
6b43ae8a JS |
984 | leap = second_overflow(timekeeper.xtime.tv_sec); |
985 | timekeeper.xtime.tv_sec += leap; | |
fad0c66c | 986 | timekeeper.wall_to_monotonic.tv_sec -= leap; |
4873fa07 JS |
987 | if (leap) |
988 | clock_was_set_delayed(); | |
a092ff0f JS |
989 | } |
990 | ||
deda2e81 JW |
991 | /* Accumulate raw time */ |
992 | raw_nsecs = timekeeper.raw_interval << shift; | |
01f71b47 | 993 | raw_nsecs += timekeeper.raw_time.tv_nsec; |
c7dcf87a JS |
994 | if (raw_nsecs >= NSEC_PER_SEC) { |
995 | u64 raw_secs = raw_nsecs; | |
996 | raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); | |
01f71b47 | 997 | timekeeper.raw_time.tv_sec += raw_secs; |
a092ff0f | 998 | } |
01f71b47 | 999 | timekeeper.raw_time.tv_nsec = raw_nsecs; |
a092ff0f JS |
1000 | |
1001 | /* Accumulate error between NTP and clock interval */ | |
ea7cf49a | 1002 | timekeeper.ntp_error += ntp_tick_length() << shift; |
a386b5af KP |
1003 | timekeeper.ntp_error -= |
1004 | (timekeeper.xtime_interval + timekeeper.xtime_remainder) << | |
a092ff0f JS |
1005 | (timekeeper.ntp_error_shift + shift); |
1006 | ||
1007 | return offset; | |
1008 | } | |
1009 | ||
83f57a11 | 1010 | |
8524070b JS |
1011 | /** |
1012 | * update_wall_time - Uses the current clocksource to increment the wall time | |
1013 | * | |
8524070b | 1014 | */ |
871cf1e5 | 1015 | static void update_wall_time(void) |
8524070b | 1016 | { |
155ec602 | 1017 | struct clocksource *clock; |
8524070b | 1018 | cycle_t offset; |
a092ff0f | 1019 | int shift = 0, maxshift; |
70471f2f JS |
1020 | unsigned long flags; |
1021 | ||
1022 | write_seqlock_irqsave(&timekeeper.lock, flags); | |
8524070b JS |
1023 | |
1024 | /* Make sure we're fully resumed: */ | |
1025 | if (unlikely(timekeeping_suspended)) | |
70471f2f | 1026 | goto out; |
8524070b | 1027 | |
155ec602 | 1028 | clock = timekeeper.clock; |
592913ec JS |
1029 | |
1030 | #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET | |
155ec602 | 1031 | offset = timekeeper.cycle_interval; |
592913ec JS |
1032 | #else |
1033 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; | |
8524070b | 1034 | #endif |
8ff2cb92 JS |
1035 | timekeeper.xtime_nsec = (s64)timekeeper.xtime.tv_nsec << |
1036 | timekeeper.shift; | |
8524070b | 1037 | |
a092ff0f JS |
1038 | /* |
1039 | * With NO_HZ we may have to accumulate many cycle_intervals | |
1040 | * (think "ticks") worth of time at once. To do this efficiently, | |
1041 | * we calculate the largest doubling multiple of cycle_intervals | |
88b28adf | 1042 | * that is smaller than the offset. We then accumulate that |
a092ff0f JS |
1043 | * chunk in one go, and then try to consume the next smaller |
1044 | * doubled multiple. | |
8524070b | 1045 | */ |
a092ff0f JS |
1046 | shift = ilog2(offset) - ilog2(timekeeper.cycle_interval); |
1047 | shift = max(0, shift); | |
88b28adf | 1048 | /* Bound shift to one less than what overflows tick_length */ |
ea7cf49a | 1049 | maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; |
a092ff0f | 1050 | shift = min(shift, maxshift); |
155ec602 | 1051 | while (offset >= timekeeper.cycle_interval) { |
a092ff0f | 1052 | offset = logarithmic_accumulation(offset, shift); |
830ec045 JS |
1053 | if(offset < timekeeper.cycle_interval<<shift) |
1054 | shift--; | |
8524070b JS |
1055 | } |
1056 | ||
1057 | /* correct the clock when NTP error is too big */ | |
155ec602 | 1058 | timekeeping_adjust(offset); |
8524070b | 1059 | |
6c9bacb4 JS |
1060 | /* |
1061 | * Since in the loop above, we accumulate any amount of time | |
1062 | * in xtime_nsec over a second into xtime.tv_sec, its possible for | |
1063 | * xtime_nsec to be fairly small after the loop. Further, if we're | |
155ec602 | 1064 | * slightly speeding the clocksource up in timekeeping_adjust(), |
6c9bacb4 JS |
1065 | * its possible the required corrective factor to xtime_nsec could |
1066 | * cause it to underflow. | |
1067 | * | |
1068 | * Now, we cannot simply roll the accumulated second back, since | |
1069 | * the NTP subsystem has been notified via second_overflow. So | |
1070 | * instead we push xtime_nsec forward by the amount we underflowed, | |
1071 | * and add that amount into the error. | |
1072 | * | |
1073 | * We'll correct this error next time through this function, when | |
1074 | * xtime_nsec is not as small. | |
1075 | */ | |
155ec602 MS |
1076 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { |
1077 | s64 neg = -(s64)timekeeper.xtime_nsec; | |
1078 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 1079 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; |
6c9bacb4 JS |
1080 | } |
1081 | ||
6a867a39 JS |
1082 | |
1083 | /* | |
1084 | * Store full nanoseconds into xtime after rounding it up and | |
5cd1c9c5 RZ |
1085 | * add the remainder to the error difference. |
1086 | */ | |
8ff2cb92 JS |
1087 | timekeeper.xtime.tv_nsec = ((s64)timekeeper.xtime_nsec >> |
1088 | timekeeper.shift) + 1; | |
1089 | timekeeper.xtime_nsec -= (s64)timekeeper.xtime.tv_nsec << | |
1090 | timekeeper.shift; | |
23ce7211 MS |
1091 | timekeeper.ntp_error += timekeeper.xtime_nsec << |
1092 | timekeeper.ntp_error_shift; | |
8524070b | 1093 | |
6a867a39 JS |
1094 | /* |
1095 | * Finally, make sure that after the rounding | |
88b28adf | 1096 | * xtime.tv_nsec isn't larger than NSEC_PER_SEC |
6a867a39 | 1097 | */ |
8ff2cb92 | 1098 | if (unlikely(timekeeper.xtime.tv_nsec >= NSEC_PER_SEC)) { |
6b43ae8a | 1099 | int leap; |
8ff2cb92 JS |
1100 | timekeeper.xtime.tv_nsec -= NSEC_PER_SEC; |
1101 | timekeeper.xtime.tv_sec++; | |
6b43ae8a JS |
1102 | leap = second_overflow(timekeeper.xtime.tv_sec); |
1103 | timekeeper.xtime.tv_sec += leap; | |
fad0c66c | 1104 | timekeeper.wall_to_monotonic.tv_sec -= leap; |
4873fa07 JS |
1105 | if (leap) |
1106 | clock_was_set_delayed(); | |
6a867a39 | 1107 | } |
83f57a11 | 1108 | |
cc06268c | 1109 | timekeeping_update(false); |
70471f2f JS |
1110 | |
1111 | out: | |
1112 | write_sequnlock_irqrestore(&timekeeper.lock, flags); | |
1113 | ||
8524070b | 1114 | } |
7c3f1a57 TJ |
1115 | |
1116 | /** | |
1117 | * getboottime - Return the real time of system boot. | |
1118 | * @ts: pointer to the timespec to be set | |
1119 | * | |
abb3a4ea | 1120 | * Returns the wall-time of boot in a timespec. |
7c3f1a57 TJ |
1121 | * |
1122 | * This is based on the wall_to_monotonic offset and the total suspend | |
1123 | * time. Calls to settimeofday will affect the value returned (which | |
1124 | * basically means that however wrong your real time clock is at boot time, | |
1125 | * you get the right time here). | |
1126 | */ | |
1127 | void getboottime(struct timespec *ts) | |
1128 | { | |
36d47481 | 1129 | struct timespec boottime = { |
d9f7217a | 1130 | .tv_sec = timekeeper.wall_to_monotonic.tv_sec + |
00c5fb77 | 1131 | timekeeper.total_sleep_time.tv_sec, |
d9f7217a | 1132 | .tv_nsec = timekeeper.wall_to_monotonic.tv_nsec + |
00c5fb77 | 1133 | timekeeper.total_sleep_time.tv_nsec |
36d47481 | 1134 | }; |
d4f587c6 | 1135 | |
d4f587c6 | 1136 | set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); |
7c3f1a57 | 1137 | } |
c93d89f3 | 1138 | EXPORT_SYMBOL_GPL(getboottime); |
7c3f1a57 | 1139 | |
abb3a4ea JS |
1140 | |
1141 | /** | |
1142 | * get_monotonic_boottime - Returns monotonic time since boot | |
1143 | * @ts: pointer to the timespec to be set | |
1144 | * | |
1145 | * Returns the monotonic time since boot in a timespec. | |
1146 | * | |
1147 | * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also | |
1148 | * includes the time spent in suspend. | |
1149 | */ | |
1150 | void get_monotonic_boottime(struct timespec *ts) | |
1151 | { | |
1152 | struct timespec tomono, sleep; | |
1153 | unsigned int seq; | |
1154 | s64 nsecs; | |
1155 | ||
1156 | WARN_ON(timekeeping_suspended); | |
1157 | ||
1158 | do { | |
70471f2f | 1159 | seq = read_seqbegin(&timekeeper.lock); |
8ff2cb92 | 1160 | *ts = timekeeper.xtime; |
d9f7217a | 1161 | tomono = timekeeper.wall_to_monotonic; |
00c5fb77 | 1162 | sleep = timekeeper.total_sleep_time; |
abb3a4ea JS |
1163 | nsecs = timekeeping_get_ns(); |
1164 | ||
70471f2f | 1165 | } while (read_seqretry(&timekeeper.lock, seq)); |
abb3a4ea JS |
1166 | |
1167 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec, | |
1168 | ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec + nsecs); | |
1169 | } | |
1170 | EXPORT_SYMBOL_GPL(get_monotonic_boottime); | |
1171 | ||
1172 | /** | |
1173 | * ktime_get_boottime - Returns monotonic time since boot in a ktime | |
1174 | * | |
1175 | * Returns the monotonic time since boot in a ktime | |
1176 | * | |
1177 | * This is similar to CLOCK_MONTONIC/ktime_get, but also | |
1178 | * includes the time spent in suspend. | |
1179 | */ | |
1180 | ktime_t ktime_get_boottime(void) | |
1181 | { | |
1182 | struct timespec ts; | |
1183 | ||
1184 | get_monotonic_boottime(&ts); | |
1185 | return timespec_to_ktime(ts); | |
1186 | } | |
1187 | EXPORT_SYMBOL_GPL(ktime_get_boottime); | |
1188 | ||
7c3f1a57 TJ |
1189 | /** |
1190 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
1191 | * @ts: pointer to the timespec to be converted | |
1192 | */ | |
1193 | void monotonic_to_bootbased(struct timespec *ts) | |
1194 | { | |
00c5fb77 | 1195 | *ts = timespec_add(*ts, timekeeper.total_sleep_time); |
7c3f1a57 | 1196 | } |
c93d89f3 | 1197 | EXPORT_SYMBOL_GPL(monotonic_to_bootbased); |
2c6b47de | 1198 | |
17c38b74 JS |
1199 | unsigned long get_seconds(void) |
1200 | { | |
8ff2cb92 | 1201 | return timekeeper.xtime.tv_sec; |
17c38b74 JS |
1202 | } |
1203 | EXPORT_SYMBOL(get_seconds); | |
1204 | ||
da15cfda JS |
1205 | struct timespec __current_kernel_time(void) |
1206 | { | |
8ff2cb92 | 1207 | return timekeeper.xtime; |
da15cfda | 1208 | } |
17c38b74 | 1209 | |
2c6b47de JS |
1210 | struct timespec current_kernel_time(void) |
1211 | { | |
1212 | struct timespec now; | |
1213 | unsigned long seq; | |
1214 | ||
1215 | do { | |
70471f2f | 1216 | seq = read_seqbegin(&timekeeper.lock); |
83f57a11 | 1217 | |
8ff2cb92 | 1218 | now = timekeeper.xtime; |
70471f2f | 1219 | } while (read_seqretry(&timekeeper.lock, seq)); |
2c6b47de JS |
1220 | |
1221 | return now; | |
1222 | } | |
2c6b47de | 1223 | EXPORT_SYMBOL(current_kernel_time); |
da15cfda JS |
1224 | |
1225 | struct timespec get_monotonic_coarse(void) | |
1226 | { | |
1227 | struct timespec now, mono; | |
1228 | unsigned long seq; | |
1229 | ||
1230 | do { | |
70471f2f | 1231 | seq = read_seqbegin(&timekeeper.lock); |
83f57a11 | 1232 | |
8ff2cb92 | 1233 | now = timekeeper.xtime; |
d9f7217a | 1234 | mono = timekeeper.wall_to_monotonic; |
70471f2f | 1235 | } while (read_seqretry(&timekeeper.lock, seq)); |
da15cfda JS |
1236 | |
1237 | set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, | |
1238 | now.tv_nsec + mono.tv_nsec); | |
1239 | return now; | |
1240 | } | |
871cf1e5 TH |
1241 | |
1242 | /* | |
1243 | * The 64-bit jiffies value is not atomic - you MUST NOT read it | |
1244 | * without sampling the sequence number in xtime_lock. | |
1245 | * jiffies is defined in the linker script... | |
1246 | */ | |
1247 | void do_timer(unsigned long ticks) | |
1248 | { | |
1249 | jiffies_64 += ticks; | |
1250 | update_wall_time(); | |
1251 | calc_global_load(ticks); | |
1252 | } | |
48cf76f7 TH |
1253 | |
1254 | /** | |
314ac371 JS |
1255 | * get_xtime_and_monotonic_and_sleep_offset() - get xtime, wall_to_monotonic, |
1256 | * and sleep offsets. | |
48cf76f7 TH |
1257 | * @xtim: pointer to timespec to be set with xtime |
1258 | * @wtom: pointer to timespec to be set with wall_to_monotonic | |
314ac371 | 1259 | * @sleep: pointer to timespec to be set with time in suspend |
48cf76f7 | 1260 | */ |
314ac371 JS |
1261 | void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, |
1262 | struct timespec *wtom, struct timespec *sleep) | |
48cf76f7 TH |
1263 | { |
1264 | unsigned long seq; | |
1265 | ||
1266 | do { | |
70471f2f | 1267 | seq = read_seqbegin(&timekeeper.lock); |
8ff2cb92 | 1268 | *xtim = timekeeper.xtime; |
d9f7217a | 1269 | *wtom = timekeeper.wall_to_monotonic; |
00c5fb77 | 1270 | *sleep = timekeeper.total_sleep_time; |
70471f2f | 1271 | } while (read_seqretry(&timekeeper.lock, seq)); |
48cf76f7 | 1272 | } |
f0af911a | 1273 | |
f6c06abf TG |
1274 | #ifdef CONFIG_HIGH_RES_TIMERS |
1275 | /** | |
1276 | * ktime_get_update_offsets - hrtimer helper | |
1277 | * @offs_real: pointer to storage for monotonic -> realtime offset | |
1278 | * @offs_boot: pointer to storage for monotonic -> boottime offset | |
1279 | * | |
1280 | * Returns current monotonic time and updates the offsets | |
1281 | * Called from hrtimer_interupt() or retrigger_next_event() | |
1282 | */ | |
1283 | ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot) | |
1284 | { | |
1285 | ktime_t now; | |
1286 | unsigned int seq; | |
1287 | u64 secs, nsecs; | |
1288 | ||
1289 | do { | |
1290 | seq = read_seqbegin(&timekeeper.lock); | |
1291 | ||
1292 | secs = timekeeper.xtime.tv_sec; | |
1293 | nsecs = timekeeper.xtime.tv_nsec; | |
1294 | nsecs += timekeeping_get_ns(); | |
1295 | /* If arch requires, add in gettimeoffset() */ | |
1296 | nsecs += arch_gettimeoffset(); | |
1297 | ||
1298 | *offs_real = timekeeper.offs_real; | |
1299 | *offs_boot = timekeeper.offs_boot; | |
1300 | } while (read_seqretry(&timekeeper.lock, seq)); | |
1301 | ||
1302 | now = ktime_add_ns(ktime_set(secs, 0), nsecs); | |
1303 | now = ktime_sub(now, *offs_real); | |
1304 | return now; | |
1305 | } | |
1306 | #endif | |
1307 | ||
99ee5315 TG |
1308 | /** |
1309 | * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format | |
1310 | */ | |
1311 | ktime_t ktime_get_monotonic_offset(void) | |
1312 | { | |
1313 | unsigned long seq; | |
1314 | struct timespec wtom; | |
1315 | ||
1316 | do { | |
70471f2f | 1317 | seq = read_seqbegin(&timekeeper.lock); |
d9f7217a | 1318 | wtom = timekeeper.wall_to_monotonic; |
70471f2f JS |
1319 | } while (read_seqretry(&timekeeper.lock, seq)); |
1320 | ||
99ee5315 TG |
1321 | return timespec_to_ktime(wtom); |
1322 | } | |
a80b83b7 JS |
1323 | EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset); |
1324 | ||
99ee5315 | 1325 | |
f0af911a TH |
1326 | /** |
1327 | * xtime_update() - advances the timekeeping infrastructure | |
1328 | * @ticks: number of ticks, that have elapsed since the last call. | |
1329 | * | |
1330 | * Must be called with interrupts disabled. | |
1331 | */ | |
1332 | void xtime_update(unsigned long ticks) | |
1333 | { | |
1334 | write_seqlock(&xtime_lock); | |
1335 | do_timer(ticks); | |
1336 | write_sequnlock(&xtime_lock); | |
1337 | } |