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