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Commit | Line | Data |
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8524070b JS |
1 | /* |
2 | * linux/kernel/time/timekeeping.c | |
3 | * | |
4 | * Kernel timekeeping code and accessor functions | |
5 | * | |
6 | * This code was moved from linux/kernel/timer.c. | |
7 | * Please see that file for copyright and history logs. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/interrupt.h> | |
13 | #include <linux/percpu.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mm.h> | |
d43c36dc | 16 | #include <linux/sched.h> |
e1a85b2c | 17 | #include <linux/syscore_ops.h> |
8524070b JS |
18 | #include <linux/clocksource.h> |
19 | #include <linux/jiffies.h> | |
20 | #include <linux/time.h> | |
21 | #include <linux/tick.h> | |
75c5158f | 22 | #include <linux/stop_machine.h> |
8524070b | 23 | |
155ec602 MS |
24 | /* Structure holding internal timekeeping values. */ |
25 | struct timekeeper { | |
26 | /* Current clocksource used for timekeeping. */ | |
27 | struct clocksource *clock; | |
23ce7211 MS |
28 | /* The shift value of the current clocksource. */ |
29 | int shift; | |
155ec602 MS |
30 | |
31 | /* Number of clock cycles in one NTP interval. */ | |
32 | cycle_t cycle_interval; | |
33 | /* Number of clock shifted nano seconds in one NTP interval. */ | |
34 | u64 xtime_interval; | |
a386b5af KP |
35 | /* shifted nano seconds left over when rounding cycle_interval */ |
36 | s64 xtime_remainder; | |
155ec602 MS |
37 | /* Raw nano seconds accumulated per NTP interval. */ |
38 | u32 raw_interval; | |
39 | ||
40 | /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */ | |
41 | u64 xtime_nsec; | |
42 | /* Difference between accumulated time and NTP time in ntp | |
43 | * shifted nano seconds. */ | |
44 | s64 ntp_error; | |
23ce7211 MS |
45 | /* Shift conversion between clock shifted nano seconds and |
46 | * ntp shifted nano seconds. */ | |
47 | int ntp_error_shift; | |
0a544198 MS |
48 | /* NTP adjusted clock multiplier */ |
49 | u32 mult; | |
00c5fb77 | 50 | |
8ff2cb92 JS |
51 | /* The current time */ |
52 | struct timespec xtime; | |
d9f7217a JS |
53 | /* |
54 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected | |
55 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged | |
56 | * at zero at system boot time, so wall_to_monotonic will be negative, | |
57 | * however, we will ALWAYS keep the tv_nsec part positive so we can use | |
58 | * the usual normalization. | |
59 | * | |
60 | * wall_to_monotonic is moved after resume from suspend for the | |
61 | * monotonic time not to jump. We need to add total_sleep_time to | |
62 | * wall_to_monotonic to get the real boot based time offset. | |
63 | * | |
64 | * - wall_to_monotonic is no longer the boot time, getboottime must be | |
65 | * used instead. | |
66 | */ | |
67 | struct timespec wall_to_monotonic; | |
00c5fb77 JS |
68 | /* time spent in suspend */ |
69 | struct timespec total_sleep_time; | |
01f71b47 JS |
70 | /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */ |
71 | struct timespec raw_time; | |
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 | ||
31089c13 JS |
175 | /* must hold xtime_lock */ |
176 | void timekeeping_leap_insert(int leapsecond) | |
177 | { | |
70471f2f JS |
178 | unsigned long flags; |
179 | ||
180 | write_seqlock_irqsave(&timekeeper.lock, flags); | |
181 | ||
8ff2cb92 | 182 | timekeeper.xtime.tv_sec += leapsecond; |
d9f7217a | 183 | timekeeper.wall_to_monotonic.tv_sec -= leapsecond; |
8ff2cb92 JS |
184 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
185 | timekeeper.clock, timekeeper.mult); | |
70471f2f JS |
186 | |
187 | write_sequnlock_irqrestore(&timekeeper.lock, flags); | |
188 | ||
31089c13 | 189 | } |
8524070b | 190 | |
8524070b | 191 | /** |
155ec602 | 192 | * timekeeping_forward_now - update clock to the current time |
8524070b | 193 | * |
9a055117 RZ |
194 | * Forward the current clock to update its state since the last call to |
195 | * update_wall_time(). This is useful before significant clock changes, | |
196 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 197 | */ |
155ec602 | 198 | static void timekeeping_forward_now(void) |
8524070b JS |
199 | { |
200 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 201 | struct clocksource *clock; |
9a055117 | 202 | s64 nsec; |
8524070b | 203 | |
155ec602 | 204 | clock = timekeeper.clock; |
a0f7d48b | 205 | cycle_now = clock->read(clock); |
8524070b | 206 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 207 | clock->cycle_last = cycle_now; |
8524070b | 208 | |
0a544198 MS |
209 | nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
210 | timekeeper.shift); | |
7d27558c JS |
211 | |
212 | /* If arch requires, add in gettimeoffset() */ | |
213 | nsec += arch_gettimeoffset(); | |
214 | ||
8ff2cb92 | 215 | timespec_add_ns(&timekeeper.xtime, nsec); |
2d42244a | 216 | |
0a544198 | 217 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
01f71b47 | 218 | timespec_add_ns(&timekeeper.raw_time, nsec); |
8524070b JS |
219 | } |
220 | ||
221 | /** | |
efd9ac86 | 222 | * getnstimeofday - Returns the time of day in a timespec |
8524070b JS |
223 | * @ts: pointer to the timespec to be set |
224 | * | |
efd9ac86 | 225 | * Returns the time of day in a timespec. |
8524070b | 226 | */ |
efd9ac86 | 227 | void getnstimeofday(struct timespec *ts) |
8524070b JS |
228 | { |
229 | unsigned long seq; | |
230 | s64 nsecs; | |
231 | ||
1c5745aa TG |
232 | WARN_ON(timekeeping_suspended); |
233 | ||
8524070b | 234 | do { |
70471f2f | 235 | seq = read_seqbegin(&timekeeper.lock); |
8524070b | 236 | |
8ff2cb92 | 237 | *ts = timekeeper.xtime; |
2ba2a305 | 238 | nsecs = timekeeping_get_ns(); |
8524070b | 239 | |
7d27558c JS |
240 | /* If arch requires, add in gettimeoffset() */ |
241 | nsecs += arch_gettimeoffset(); | |
242 | ||
70471f2f | 243 | } while (read_seqretry(&timekeeper.lock, seq)); |
8524070b JS |
244 | |
245 | timespec_add_ns(ts, nsecs); | |
246 | } | |
247 | ||
8524070b JS |
248 | EXPORT_SYMBOL(getnstimeofday); |
249 | ||
951ed4d3 MS |
250 | ktime_t ktime_get(void) |
251 | { | |
951ed4d3 MS |
252 | unsigned int seq; |
253 | s64 secs, nsecs; | |
254 | ||
255 | WARN_ON(timekeeping_suspended); | |
256 | ||
257 | do { | |
70471f2f | 258 | seq = read_seqbegin(&timekeeper.lock); |
8ff2cb92 JS |
259 | secs = timekeeper.xtime.tv_sec + |
260 | timekeeper.wall_to_monotonic.tv_sec; | |
261 | nsecs = timekeeper.xtime.tv_nsec + | |
262 | timekeeper.wall_to_monotonic.tv_nsec; | |
2ba2a305 | 263 | nsecs += timekeeping_get_ns(); |
d004e024 HP |
264 | /* If arch requires, add in gettimeoffset() */ |
265 | nsecs += arch_gettimeoffset(); | |
951ed4d3 | 266 | |
70471f2f | 267 | } while (read_seqretry(&timekeeper.lock, seq)); |
951ed4d3 MS |
268 | /* |
269 | * Use ktime_set/ktime_add_ns to create a proper ktime on | |
270 | * 32-bit architectures without CONFIG_KTIME_SCALAR. | |
271 | */ | |
272 | return ktime_add_ns(ktime_set(secs, 0), nsecs); | |
273 | } | |
274 | EXPORT_SYMBOL_GPL(ktime_get); | |
275 | ||
276 | /** | |
277 | * ktime_get_ts - get the monotonic clock in timespec format | |
278 | * @ts: pointer to timespec variable | |
279 | * | |
280 | * The function calculates the monotonic clock from the realtime | |
281 | * clock and the wall_to_monotonic offset and stores the result | |
282 | * in normalized timespec format in the variable pointed to by @ts. | |
283 | */ | |
284 | void ktime_get_ts(struct timespec *ts) | |
285 | { | |
951ed4d3 MS |
286 | struct timespec tomono; |
287 | unsigned int seq; | |
288 | s64 nsecs; | |
289 | ||
290 | WARN_ON(timekeeping_suspended); | |
291 | ||
292 | do { | |
70471f2f | 293 | seq = read_seqbegin(&timekeeper.lock); |
8ff2cb92 | 294 | *ts = timekeeper.xtime; |
d9f7217a | 295 | tomono = timekeeper.wall_to_monotonic; |
2ba2a305 | 296 | nsecs = timekeeping_get_ns(); |
d004e024 HP |
297 | /* If arch requires, add in gettimeoffset() */ |
298 | nsecs += arch_gettimeoffset(); | |
951ed4d3 | 299 | |
70471f2f | 300 | } while (read_seqretry(&timekeeper.lock, seq)); |
951ed4d3 MS |
301 | |
302 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
303 | ts->tv_nsec + tomono.tv_nsec + nsecs); | |
304 | } | |
305 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
306 | ||
e2c18e49 AG |
307 | #ifdef CONFIG_NTP_PPS |
308 | ||
309 | /** | |
310 | * getnstime_raw_and_real - get day and raw monotonic time in timespec format | |
311 | * @ts_raw: pointer to the timespec to be set to raw monotonic time | |
312 | * @ts_real: pointer to the timespec to be set to the time of day | |
313 | * | |
314 | * This function reads both the time of day and raw monotonic time at the | |
315 | * same time atomically and stores the resulting timestamps in timespec | |
316 | * format. | |
317 | */ | |
318 | void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) | |
319 | { | |
320 | unsigned long seq; | |
321 | s64 nsecs_raw, nsecs_real; | |
322 | ||
323 | WARN_ON_ONCE(timekeeping_suspended); | |
324 | ||
325 | do { | |
326 | u32 arch_offset; | |
327 | ||
70471f2f | 328 | seq = read_seqbegin(&timekeeper.lock); |
e2c18e49 | 329 | |
01f71b47 | 330 | *ts_raw = timekeeper.raw_time; |
8ff2cb92 | 331 | *ts_real = timekeeper.xtime; |
e2c18e49 AG |
332 | |
333 | nsecs_raw = timekeeping_get_ns_raw(); | |
334 | nsecs_real = timekeeping_get_ns(); | |
335 | ||
336 | /* If arch requires, add in gettimeoffset() */ | |
337 | arch_offset = arch_gettimeoffset(); | |
338 | nsecs_raw += arch_offset; | |
339 | nsecs_real += arch_offset; | |
340 | ||
70471f2f | 341 | } while (read_seqretry(&timekeeper.lock, seq)); |
e2c18e49 AG |
342 | |
343 | timespec_add_ns(ts_raw, nsecs_raw); | |
344 | timespec_add_ns(ts_real, nsecs_real); | |
345 | } | |
346 | EXPORT_SYMBOL(getnstime_raw_and_real); | |
347 | ||
348 | #endif /* CONFIG_NTP_PPS */ | |
349 | ||
8524070b JS |
350 | /** |
351 | * do_gettimeofday - Returns the time of day in a timeval | |
352 | * @tv: pointer to the timeval to be set | |
353 | * | |
efd9ac86 | 354 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b JS |
355 | */ |
356 | void do_gettimeofday(struct timeval *tv) | |
357 | { | |
358 | struct timespec now; | |
359 | ||
efd9ac86 | 360 | getnstimeofday(&now); |
8524070b JS |
361 | tv->tv_sec = now.tv_sec; |
362 | tv->tv_usec = now.tv_nsec/1000; | |
363 | } | |
364 | ||
365 | EXPORT_SYMBOL(do_gettimeofday); | |
366 | /** | |
367 | * do_settimeofday - Sets the time of day | |
368 | * @tv: pointer to the timespec variable containing the new time | |
369 | * | |
370 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
371 | */ | |
1e6d7679 | 372 | int do_settimeofday(const struct timespec *tv) |
8524070b | 373 | { |
9a055117 | 374 | struct timespec ts_delta; |
70471f2f | 375 | unsigned long flags1,flags2; |
8524070b JS |
376 | |
377 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
378 | return -EINVAL; | |
379 | ||
70471f2f JS |
380 | write_seqlock_irqsave(&xtime_lock, flags1); |
381 | write_seqlock_irqsave(&timekeeper.lock, flags2); | |
8524070b | 382 | |
155ec602 | 383 | timekeeping_forward_now(); |
9a055117 | 384 | |
8ff2cb92 JS |
385 | ts_delta.tv_sec = tv->tv_sec - timekeeper.xtime.tv_sec; |
386 | ts_delta.tv_nsec = tv->tv_nsec - timekeeper.xtime.tv_nsec; | |
d9f7217a JS |
387 | timekeeper.wall_to_monotonic = |
388 | timespec_sub(timekeeper.wall_to_monotonic, ts_delta); | |
8524070b | 389 | |
8ff2cb92 | 390 | timekeeper.xtime = *tv; |
8524070b | 391 | |
155ec602 | 392 | timekeeper.ntp_error = 0; |
8524070b JS |
393 | ntp_clear(); |
394 | ||
8ff2cb92 JS |
395 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
396 | timekeeper.clock, timekeeper.mult); | |
8524070b | 397 | |
70471f2f JS |
398 | write_sequnlock_irqrestore(&timekeeper.lock, flags2); |
399 | write_sequnlock_irqrestore(&xtime_lock, flags1); | |
8524070b JS |
400 | |
401 | /* signal hrtimers about time change */ | |
402 | clock_was_set(); | |
403 | ||
404 | return 0; | |
405 | } | |
406 | ||
407 | EXPORT_SYMBOL(do_settimeofday); | |
408 | ||
c528f7c6 JS |
409 | |
410 | /** | |
411 | * timekeeping_inject_offset - Adds or subtracts from the current time. | |
412 | * @tv: pointer to the timespec variable containing the offset | |
413 | * | |
414 | * Adds or subtracts an offset value from the current time. | |
415 | */ | |
416 | int timekeeping_inject_offset(struct timespec *ts) | |
417 | { | |
70471f2f | 418 | unsigned long flags1,flags2; |
c528f7c6 JS |
419 | |
420 | if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) | |
421 | return -EINVAL; | |
422 | ||
70471f2f JS |
423 | write_seqlock_irqsave(&xtime_lock, flags1); |
424 | write_seqlock_irqsave(&timekeeper.lock, flags2); | |
c528f7c6 JS |
425 | |
426 | timekeeping_forward_now(); | |
427 | ||
8ff2cb92 | 428 | timekeeper.xtime = timespec_add(timekeeper.xtime, *ts); |
d9f7217a JS |
429 | timekeeper.wall_to_monotonic = |
430 | timespec_sub(timekeeper.wall_to_monotonic, *ts); | |
c528f7c6 JS |
431 | |
432 | timekeeper.ntp_error = 0; | |
433 | ntp_clear(); | |
434 | ||
8ff2cb92 JS |
435 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
436 | timekeeper.clock, timekeeper.mult); | |
c528f7c6 | 437 | |
70471f2f JS |
438 | write_sequnlock_irqrestore(&timekeeper.lock, flags2); |
439 | write_sequnlock_irqrestore(&xtime_lock, flags1); | |
c528f7c6 JS |
440 | |
441 | /* signal hrtimers about time change */ | |
442 | clock_was_set(); | |
443 | ||
444 | return 0; | |
445 | } | |
446 | EXPORT_SYMBOL(timekeeping_inject_offset); | |
447 | ||
8524070b JS |
448 | /** |
449 | * change_clocksource - Swaps clocksources if a new one is available | |
450 | * | |
451 | * Accumulates current time interval and initializes new clocksource | |
452 | */ | |
75c5158f | 453 | static int change_clocksource(void *data) |
8524070b | 454 | { |
4614e6ad | 455 | struct clocksource *new, *old; |
8524070b | 456 | |
75c5158f | 457 | new = (struct clocksource *) data; |
8524070b | 458 | |
155ec602 | 459 | timekeeping_forward_now(); |
75c5158f MS |
460 | if (!new->enable || new->enable(new) == 0) { |
461 | old = timekeeper.clock; | |
462 | timekeeper_setup_internals(new); | |
463 | if (old->disable) | |
464 | old->disable(old); | |
465 | } | |
466 | return 0; | |
467 | } | |
8524070b | 468 | |
75c5158f MS |
469 | /** |
470 | * timekeeping_notify - Install a new clock source | |
471 | * @clock: pointer to the clock source | |
472 | * | |
473 | * This function is called from clocksource.c after a new, better clock | |
474 | * source has been registered. The caller holds the clocksource_mutex. | |
475 | */ | |
476 | void timekeeping_notify(struct clocksource *clock) | |
477 | { | |
478 | if (timekeeper.clock == clock) | |
4614e6ad | 479 | return; |
75c5158f | 480 | stop_machine(change_clocksource, clock, NULL); |
8524070b | 481 | tick_clock_notify(); |
8524070b | 482 | } |
75c5158f | 483 | |
a40f262c TG |
484 | /** |
485 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
486 | * | |
487 | * returns the time in ktime_t format | |
488 | */ | |
489 | ktime_t ktime_get_real(void) | |
490 | { | |
491 | struct timespec now; | |
492 | ||
493 | getnstimeofday(&now); | |
494 | ||
495 | return timespec_to_ktime(now); | |
496 | } | |
497 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
8524070b | 498 | |
2d42244a JS |
499 | /** |
500 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
501 | * @ts: pointer to the timespec to be set | |
502 | * | |
503 | * Returns the raw monotonic time (completely un-modified by ntp) | |
504 | */ | |
505 | void getrawmonotonic(struct timespec *ts) | |
506 | { | |
507 | unsigned long seq; | |
508 | s64 nsecs; | |
2d42244a JS |
509 | |
510 | do { | |
70471f2f | 511 | seq = read_seqbegin(&timekeeper.lock); |
2ba2a305 | 512 | nsecs = timekeeping_get_ns_raw(); |
01f71b47 | 513 | *ts = timekeeper.raw_time; |
2d42244a | 514 | |
70471f2f | 515 | } while (read_seqretry(&timekeeper.lock, seq)); |
2d42244a JS |
516 | |
517 | timespec_add_ns(ts, nsecs); | |
518 | } | |
519 | EXPORT_SYMBOL(getrawmonotonic); | |
520 | ||
521 | ||
8524070b | 522 | /** |
cf4fc6cb | 523 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 524 | */ |
cf4fc6cb | 525 | int timekeeping_valid_for_hres(void) |
8524070b JS |
526 | { |
527 | unsigned long seq; | |
528 | int ret; | |
529 | ||
530 | do { | |
70471f2f | 531 | seq = read_seqbegin(&timekeeper.lock); |
8524070b | 532 | |
155ec602 | 533 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
8524070b | 534 | |
70471f2f | 535 | } while (read_seqretry(&timekeeper.lock, seq)); |
8524070b JS |
536 | |
537 | return ret; | |
538 | } | |
539 | ||
98962465 JH |
540 | /** |
541 | * timekeeping_max_deferment - Returns max time the clocksource can be deferred | |
98962465 JH |
542 | */ |
543 | u64 timekeeping_max_deferment(void) | |
544 | { | |
70471f2f JS |
545 | unsigned long seq; |
546 | u64 ret; | |
547 | do { | |
548 | seq = read_seqbegin(&timekeeper.lock); | |
549 | ||
550 | ret = timekeeper.clock->max_idle_ns; | |
551 | ||
552 | } while (read_seqretry(&timekeeper.lock, seq)); | |
553 | ||
554 | return ret; | |
98962465 JH |
555 | } |
556 | ||
8524070b | 557 | /** |
d4f587c6 | 558 | * read_persistent_clock - Return time from the persistent clock. |
8524070b JS |
559 | * |
560 | * Weak dummy function for arches that do not yet support it. | |
d4f587c6 MS |
561 | * Reads the time from the battery backed persistent clock. |
562 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
8524070b JS |
563 | * |
564 | * XXX - Do be sure to remove it once all arches implement it. | |
565 | */ | |
d4f587c6 | 566 | void __attribute__((weak)) read_persistent_clock(struct timespec *ts) |
8524070b | 567 | { |
d4f587c6 MS |
568 | ts->tv_sec = 0; |
569 | ts->tv_nsec = 0; | |
8524070b JS |
570 | } |
571 | ||
23970e38 MS |
572 | /** |
573 | * read_boot_clock - Return time of the system start. | |
574 | * | |
575 | * Weak dummy function for arches that do not yet support it. | |
576 | * Function to read the exact time the system has been started. | |
577 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
578 | * | |
579 | * XXX - Do be sure to remove it once all arches implement it. | |
580 | */ | |
581 | void __attribute__((weak)) read_boot_clock(struct timespec *ts) | |
582 | { | |
583 | ts->tv_sec = 0; | |
584 | ts->tv_nsec = 0; | |
585 | } | |
586 | ||
8524070b JS |
587 | /* |
588 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
589 | */ | |
590 | void __init timekeeping_init(void) | |
591 | { | |
155ec602 | 592 | struct clocksource *clock; |
8524070b | 593 | unsigned long flags; |
23970e38 | 594 | struct timespec now, boot; |
d4f587c6 MS |
595 | |
596 | read_persistent_clock(&now); | |
23970e38 | 597 | read_boot_clock(&boot); |
8524070b | 598 | |
70471f2f | 599 | seqlock_init(&timekeeper.lock); |
8524070b | 600 | |
70471f2f | 601 | write_seqlock_irqsave(&xtime_lock, flags); |
7dffa3c6 | 602 | ntp_init(); |
70471f2f | 603 | write_sequnlock_irqrestore(&xtime_lock, flags); |
8524070b | 604 | |
70471f2f | 605 | write_seqlock_irqsave(&timekeeper.lock, flags); |
f1b82746 | 606 | clock = clocksource_default_clock(); |
a0f7d48b MS |
607 | if (clock->enable) |
608 | clock->enable(clock); | |
155ec602 | 609 | timekeeper_setup_internals(clock); |
8524070b | 610 | |
8ff2cb92 JS |
611 | timekeeper.xtime.tv_sec = now.tv_sec; |
612 | timekeeper.xtime.tv_nsec = now.tv_nsec; | |
01f71b47 JS |
613 | timekeeper.raw_time.tv_sec = 0; |
614 | timekeeper.raw_time.tv_nsec = 0; | |
23970e38 | 615 | if (boot.tv_sec == 0 && boot.tv_nsec == 0) { |
8ff2cb92 JS |
616 | boot.tv_sec = timekeeper.xtime.tv_sec; |
617 | boot.tv_nsec = timekeeper.xtime.tv_nsec; | |
23970e38 | 618 | } |
d9f7217a | 619 | set_normalized_timespec(&timekeeper.wall_to_monotonic, |
23970e38 | 620 | -boot.tv_sec, -boot.tv_nsec); |
00c5fb77 JS |
621 | timekeeper.total_sleep_time.tv_sec = 0; |
622 | timekeeper.total_sleep_time.tv_nsec = 0; | |
70471f2f | 623 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
624 | } |
625 | ||
8524070b | 626 | /* time in seconds when suspend began */ |
d4f587c6 | 627 | static struct timespec timekeeping_suspend_time; |
8524070b | 628 | |
304529b1 JS |
629 | /** |
630 | * __timekeeping_inject_sleeptime - Internal function to add sleep interval | |
631 | * @delta: pointer to a timespec delta value | |
632 | * | |
633 | * Takes a timespec offset measuring a suspend interval and properly | |
634 | * adds the sleep offset to the timekeeping variables. | |
635 | */ | |
636 | static void __timekeeping_inject_sleeptime(struct timespec *delta) | |
637 | { | |
cb5de2f8 | 638 | if (!timespec_valid(delta)) { |
cbaa5152 | 639 | printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid " |
cb5de2f8 JS |
640 | "sleep delta value!\n"); |
641 | return; | |
642 | } | |
643 | ||
8ff2cb92 | 644 | timekeeper.xtime = timespec_add(timekeeper.xtime, *delta); |
d9f7217a JS |
645 | timekeeper.wall_to_monotonic = |
646 | timespec_sub(timekeeper.wall_to_monotonic, *delta); | |
00c5fb77 JS |
647 | timekeeper.total_sleep_time = timespec_add( |
648 | timekeeper.total_sleep_time, *delta); | |
304529b1 JS |
649 | } |
650 | ||
651 | ||
652 | /** | |
653 | * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values | |
654 | * @delta: pointer to a timespec delta value | |
655 | * | |
656 | * This hook is for architectures that cannot support read_persistent_clock | |
657 | * because their RTC/persistent clock is only accessible when irqs are enabled. | |
658 | * | |
659 | * This function should only be called by rtc_resume(), and allows | |
660 | * a suspend offset to be injected into the timekeeping values. | |
661 | */ | |
662 | void timekeeping_inject_sleeptime(struct timespec *delta) | |
663 | { | |
70471f2f | 664 | unsigned long flags1,flags2; |
304529b1 JS |
665 | struct timespec ts; |
666 | ||
667 | /* Make sure we don't set the clock twice */ | |
668 | read_persistent_clock(&ts); | |
669 | if (!(ts.tv_sec == 0 && ts.tv_nsec == 0)) | |
670 | return; | |
671 | ||
70471f2f JS |
672 | write_seqlock_irqsave(&xtime_lock, flags1); |
673 | write_seqlock_irqsave(&timekeeper.lock, flags2); | |
674 | ||
304529b1 JS |
675 | timekeeping_forward_now(); |
676 | ||
677 | __timekeeping_inject_sleeptime(delta); | |
678 | ||
679 | timekeeper.ntp_error = 0; | |
680 | ntp_clear(); | |
8ff2cb92 JS |
681 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
682 | timekeeper.clock, timekeeper.mult); | |
304529b1 | 683 | |
70471f2f JS |
684 | write_sequnlock_irqrestore(&timekeeper.lock, flags2); |
685 | write_sequnlock_irqrestore(&xtime_lock, flags1); | |
304529b1 JS |
686 | |
687 | /* signal hrtimers about time change */ | |
688 | clock_was_set(); | |
689 | } | |
690 | ||
691 | ||
8524070b JS |
692 | /** |
693 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
8524070b JS |
694 | * |
695 | * This is for the generic clocksource timekeeping. | |
696 | * xtime/wall_to_monotonic/jiffies/etc are | |
697 | * still managed by arch specific suspend/resume code. | |
698 | */ | |
e1a85b2c | 699 | static void timekeeping_resume(void) |
8524070b | 700 | { |
70471f2f | 701 | unsigned long flags1,flags2; |
d4f587c6 MS |
702 | struct timespec ts; |
703 | ||
704 | read_persistent_clock(&ts); | |
8524070b | 705 | |
d10ff3fb TG |
706 | clocksource_resume(); |
707 | ||
70471f2f JS |
708 | write_seqlock_irqsave(&xtime_lock, flags1); |
709 | write_seqlock_irqsave(&timekeeper.lock, flags2); | |
8524070b | 710 | |
d4f587c6 MS |
711 | if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { |
712 | ts = timespec_sub(ts, timekeeping_suspend_time); | |
304529b1 | 713 | __timekeeping_inject_sleeptime(&ts); |
8524070b JS |
714 | } |
715 | /* re-base the last cycle value */ | |
155ec602 MS |
716 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
717 | timekeeper.ntp_error = 0; | |
8524070b | 718 | timekeeping_suspended = 0; |
70471f2f JS |
719 | write_sequnlock_irqrestore(&timekeeper.lock, flags2); |
720 | write_sequnlock_irqrestore(&xtime_lock, flags1); | |
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 | { |
70471f2f | 732 | unsigned long flags1,flags2; |
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 | |
70471f2f JS |
738 | write_seqlock_irqsave(&xtime_lock, flags1); |
739 | write_seqlock_irqsave(&timekeeper.lock, flags2); | |
155ec602 | 740 | timekeeping_forward_now(); |
8524070b | 741 | timekeeping_suspended = 1; |
cb33217b JS |
742 | |
743 | /* | |
744 | * To avoid drift caused by repeated suspend/resumes, | |
745 | * which each can add ~1 second drift error, | |
746 | * try to compensate so the difference in system time | |
747 | * and persistent_clock time stays close to constant. | |
748 | */ | |
8ff2cb92 | 749 | delta = timespec_sub(timekeeper.xtime, timekeeping_suspend_time); |
cb33217b JS |
750 | delta_delta = timespec_sub(delta, old_delta); |
751 | if (abs(delta_delta.tv_sec) >= 2) { | |
752 | /* | |
753 | * if delta_delta is too large, assume time correction | |
754 | * has occured and set old_delta to the current delta. | |
755 | */ | |
756 | old_delta = delta; | |
757 | } else { | |
758 | /* Otherwise try to adjust old_system to compensate */ | |
759 | timekeeping_suspend_time = | |
760 | timespec_add(timekeeping_suspend_time, delta_delta); | |
761 | } | |
70471f2f JS |
762 | write_sequnlock_irqrestore(&timekeeper.lock, flags2); |
763 | write_sequnlock_irqrestore(&xtime_lock, flags1); | |
8524070b JS |
764 | |
765 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
c54a42b1 | 766 | clocksource_suspend(); |
8524070b JS |
767 | |
768 | return 0; | |
769 | } | |
770 | ||
771 | /* sysfs resume/suspend bits for timekeeping */ | |
e1a85b2c | 772 | static struct syscore_ops timekeeping_syscore_ops = { |
8524070b JS |
773 | .resume = timekeeping_resume, |
774 | .suspend = timekeeping_suspend, | |
8524070b JS |
775 | }; |
776 | ||
e1a85b2c | 777 | static int __init timekeeping_init_ops(void) |
8524070b | 778 | { |
e1a85b2c RW |
779 | register_syscore_ops(&timekeeping_syscore_ops); |
780 | return 0; | |
8524070b JS |
781 | } |
782 | ||
e1a85b2c | 783 | device_initcall(timekeeping_init_ops); |
8524070b JS |
784 | |
785 | /* | |
786 | * If the error is already larger, we look ahead even further | |
787 | * to compensate for late or lost adjustments. | |
788 | */ | |
155ec602 | 789 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
8524070b JS |
790 | s64 *offset) |
791 | { | |
792 | s64 tick_error, i; | |
793 | u32 look_ahead, adj; | |
794 | s32 error2, mult; | |
795 | ||
796 | /* | |
797 | * Use the current error value to determine how much to look ahead. | |
798 | * The larger the error the slower we adjust for it to avoid problems | |
799 | * with losing too many ticks, otherwise we would overadjust and | |
800 | * produce an even larger error. The smaller the adjustment the | |
801 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 802 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b JS |
803 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
804 | */ | |
155ec602 | 805 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b JS |
806 | error2 = abs(error2); |
807 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
808 | error2 >>= 2; | |
809 | ||
810 | /* | |
811 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
812 | * remove the single look ahead already included in the error. | |
813 | */ | |
ea7cf49a | 814 | tick_error = ntp_tick_length() >> (timekeeper.ntp_error_shift + 1); |
155ec602 | 815 | tick_error -= timekeeper.xtime_interval >> 1; |
8524070b JS |
816 | error = ((error - tick_error) >> look_ahead) + tick_error; |
817 | ||
818 | /* Finally calculate the adjustment shift value. */ | |
819 | i = *interval; | |
820 | mult = 1; | |
821 | if (error < 0) { | |
822 | error = -error; | |
823 | *interval = -*interval; | |
824 | *offset = -*offset; | |
825 | mult = -1; | |
826 | } | |
827 | for (adj = 0; error > i; adj++) | |
828 | error >>= 1; | |
829 | ||
830 | *interval <<= adj; | |
831 | *offset <<= adj; | |
832 | return mult << adj; | |
833 | } | |
834 | ||
835 | /* | |
836 | * Adjust the multiplier to reduce the error value, | |
837 | * this is optimized for the most common adjustments of -1,0,1, | |
838 | * for other values we can do a bit more work. | |
839 | */ | |
155ec602 | 840 | static void timekeeping_adjust(s64 offset) |
8524070b | 841 | { |
155ec602 | 842 | s64 error, interval = timekeeper.cycle_interval; |
8524070b JS |
843 | int adj; |
844 | ||
c2bc1111 JS |
845 | /* |
846 | * The point of this is to check if the error is greater then half | |
847 | * an interval. | |
848 | * | |
849 | * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs. | |
850 | * | |
851 | * Note we subtract one in the shift, so that error is really error*2. | |
3f86f28f JS |
852 | * This "saves" dividing(shifting) interval twice, but keeps the |
853 | * (error > interval) comparison as still measuring if error is | |
c2bc1111 JS |
854 | * larger then half an interval. |
855 | * | |
3f86f28f | 856 | * Note: It does not "save" on aggravation when reading the code. |
c2bc1111 | 857 | */ |
23ce7211 | 858 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
8524070b | 859 | if (error > interval) { |
c2bc1111 JS |
860 | /* |
861 | * We now divide error by 4(via shift), which checks if | |
862 | * the error is greater then twice the interval. | |
863 | * If it is greater, we need a bigadjust, if its smaller, | |
864 | * we can adjust by 1. | |
865 | */ | |
8524070b | 866 | error >>= 2; |
c2bc1111 JS |
867 | /* |
868 | * XXX - In update_wall_time, we round up to the next | |
869 | * nanosecond, and store the amount rounded up into | |
870 | * the error. This causes the likely below to be unlikely. | |
871 | * | |
3f86f28f | 872 | * The proper fix is to avoid rounding up by using |
c2bc1111 JS |
873 | * the high precision timekeeper.xtime_nsec instead of |
874 | * xtime.tv_nsec everywhere. Fixing this will take some | |
875 | * time. | |
876 | */ | |
8524070b JS |
877 | if (likely(error <= interval)) |
878 | adj = 1; | |
879 | else | |
155ec602 | 880 | adj = timekeeping_bigadjust(error, &interval, &offset); |
8524070b | 881 | } else if (error < -interval) { |
c2bc1111 | 882 | /* See comment above, this is just switched for the negative */ |
8524070b JS |
883 | error >>= 2; |
884 | if (likely(error >= -interval)) { | |
885 | adj = -1; | |
886 | interval = -interval; | |
887 | offset = -offset; | |
888 | } else | |
155ec602 | 889 | adj = timekeeping_bigadjust(error, &interval, &offset); |
c2bc1111 | 890 | } else /* No adjustment needed */ |
8524070b JS |
891 | return; |
892 | ||
d65670a7 JS |
893 | WARN_ONCE(timekeeper.clock->maxadj && |
894 | (timekeeper.mult + adj > timekeeper.clock->mult + | |
895 | timekeeper.clock->maxadj), | |
896 | "Adjusting %s more then 11%% (%ld vs %ld)\n", | |
897 | timekeeper.clock->name, (long)timekeeper.mult + adj, | |
898 | (long)timekeeper.clock->mult + | |
899 | timekeeper.clock->maxadj); | |
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 JS |
970 | |
971 | /* If the offset is smaller then a shifted interval, do nothing */ | |
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) { | |
981 | timekeeper.xtime_nsec -= nsecps; | |
8ff2cb92 | 982 | timekeeper.xtime.tv_sec++; |
a092ff0f JS |
983 | second_overflow(); |
984 | } | |
985 | ||
deda2e81 JW |
986 | /* Accumulate raw time */ |
987 | raw_nsecs = timekeeper.raw_interval << shift; | |
01f71b47 | 988 | raw_nsecs += timekeeper.raw_time.tv_nsec; |
c7dcf87a JS |
989 | if (raw_nsecs >= NSEC_PER_SEC) { |
990 | u64 raw_secs = raw_nsecs; | |
991 | raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); | |
01f71b47 | 992 | timekeeper.raw_time.tv_sec += raw_secs; |
a092ff0f | 993 | } |
01f71b47 | 994 | timekeeper.raw_time.tv_nsec = raw_nsecs; |
a092ff0f JS |
995 | |
996 | /* Accumulate error between NTP and clock interval */ | |
ea7cf49a | 997 | timekeeper.ntp_error += ntp_tick_length() << shift; |
a386b5af KP |
998 | timekeeper.ntp_error -= |
999 | (timekeeper.xtime_interval + timekeeper.xtime_remainder) << | |
a092ff0f JS |
1000 | (timekeeper.ntp_error_shift + shift); |
1001 | ||
1002 | return offset; | |
1003 | } | |
1004 | ||
83f57a11 | 1005 | |
8524070b JS |
1006 | /** |
1007 | * update_wall_time - Uses the current clocksource to increment the wall time | |
1008 | * | |
1009 | * Called from the timer interrupt, must hold a write on xtime_lock. | |
1010 | */ | |
871cf1e5 | 1011 | static void update_wall_time(void) |
8524070b | 1012 | { |
155ec602 | 1013 | struct clocksource *clock; |
8524070b | 1014 | cycle_t offset; |
a092ff0f | 1015 | int shift = 0, maxshift; |
70471f2f JS |
1016 | unsigned long flags; |
1017 | ||
1018 | write_seqlock_irqsave(&timekeeper.lock, flags); | |
8524070b JS |
1019 | |
1020 | /* Make sure we're fully resumed: */ | |
1021 | if (unlikely(timekeeping_suspended)) | |
70471f2f | 1022 | goto out; |
8524070b | 1023 | |
155ec602 | 1024 | clock = timekeeper.clock; |
592913ec JS |
1025 | |
1026 | #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET | |
155ec602 | 1027 | offset = timekeeper.cycle_interval; |
592913ec JS |
1028 | #else |
1029 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; | |
8524070b | 1030 | #endif |
8ff2cb92 JS |
1031 | timekeeper.xtime_nsec = (s64)timekeeper.xtime.tv_nsec << |
1032 | timekeeper.shift; | |
8524070b | 1033 | |
a092ff0f JS |
1034 | /* |
1035 | * With NO_HZ we may have to accumulate many cycle_intervals | |
1036 | * (think "ticks") worth of time at once. To do this efficiently, | |
1037 | * we calculate the largest doubling multiple of cycle_intervals | |
1038 | * that is smaller then the offset. We then accumulate that | |
1039 | * chunk in one go, and then try to consume the next smaller | |
1040 | * doubled multiple. | |
8524070b | 1041 | */ |
a092ff0f JS |
1042 | shift = ilog2(offset) - ilog2(timekeeper.cycle_interval); |
1043 | shift = max(0, shift); | |
1044 | /* Bound shift to one less then what overflows tick_length */ | |
ea7cf49a | 1045 | maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; |
a092ff0f | 1046 | shift = min(shift, maxshift); |
155ec602 | 1047 | while (offset >= timekeeper.cycle_interval) { |
a092ff0f | 1048 | offset = logarithmic_accumulation(offset, shift); |
830ec045 JS |
1049 | if(offset < timekeeper.cycle_interval<<shift) |
1050 | shift--; | |
8524070b JS |
1051 | } |
1052 | ||
1053 | /* correct the clock when NTP error is too big */ | |
155ec602 | 1054 | timekeeping_adjust(offset); |
8524070b | 1055 | |
6c9bacb4 JS |
1056 | /* |
1057 | * Since in the loop above, we accumulate any amount of time | |
1058 | * in xtime_nsec over a second into xtime.tv_sec, its possible for | |
1059 | * xtime_nsec to be fairly small after the loop. Further, if we're | |
155ec602 | 1060 | * slightly speeding the clocksource up in timekeeping_adjust(), |
6c9bacb4 JS |
1061 | * its possible the required corrective factor to xtime_nsec could |
1062 | * cause it to underflow. | |
1063 | * | |
1064 | * Now, we cannot simply roll the accumulated second back, since | |
1065 | * the NTP subsystem has been notified via second_overflow. So | |
1066 | * instead we push xtime_nsec forward by the amount we underflowed, | |
1067 | * and add that amount into the error. | |
1068 | * | |
1069 | * We'll correct this error next time through this function, when | |
1070 | * xtime_nsec is not as small. | |
1071 | */ | |
155ec602 MS |
1072 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { |
1073 | s64 neg = -(s64)timekeeper.xtime_nsec; | |
1074 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 1075 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; |
6c9bacb4 JS |
1076 | } |
1077 | ||
6a867a39 JS |
1078 | |
1079 | /* | |
1080 | * Store full nanoseconds into xtime after rounding it up and | |
5cd1c9c5 RZ |
1081 | * add the remainder to the error difference. |
1082 | */ | |
8ff2cb92 JS |
1083 | timekeeper.xtime.tv_nsec = ((s64)timekeeper.xtime_nsec >> |
1084 | timekeeper.shift) + 1; | |
1085 | timekeeper.xtime_nsec -= (s64)timekeeper.xtime.tv_nsec << | |
1086 | timekeeper.shift; | |
23ce7211 MS |
1087 | timekeeper.ntp_error += timekeeper.xtime_nsec << |
1088 | timekeeper.ntp_error_shift; | |
8524070b | 1089 | |
6a867a39 JS |
1090 | /* |
1091 | * Finally, make sure that after the rounding | |
1092 | * xtime.tv_nsec isn't larger then NSEC_PER_SEC | |
1093 | */ | |
8ff2cb92 JS |
1094 | if (unlikely(timekeeper.xtime.tv_nsec >= NSEC_PER_SEC)) { |
1095 | timekeeper.xtime.tv_nsec -= NSEC_PER_SEC; | |
1096 | timekeeper.xtime.tv_sec++; | |
6a867a39 JS |
1097 | second_overflow(); |
1098 | } | |
83f57a11 | 1099 | |
8524070b | 1100 | /* check to see if there is a new clocksource to use */ |
8ff2cb92 JS |
1101 | update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic, |
1102 | timekeeper.clock, timekeeper.mult); | |
70471f2f JS |
1103 | |
1104 | out: | |
1105 | write_sequnlock_irqrestore(&timekeeper.lock, flags); | |
1106 | ||
8524070b | 1107 | } |
7c3f1a57 TJ |
1108 | |
1109 | /** | |
1110 | * getboottime - Return the real time of system boot. | |
1111 | * @ts: pointer to the timespec to be set | |
1112 | * | |
abb3a4ea | 1113 | * Returns the wall-time of boot in a timespec. |
7c3f1a57 TJ |
1114 | * |
1115 | * This is based on the wall_to_monotonic offset and the total suspend | |
1116 | * time. Calls to settimeofday will affect the value returned (which | |
1117 | * basically means that however wrong your real time clock is at boot time, | |
1118 | * you get the right time here). | |
1119 | */ | |
1120 | void getboottime(struct timespec *ts) | |
1121 | { | |
36d47481 | 1122 | struct timespec boottime = { |
d9f7217a | 1123 | .tv_sec = timekeeper.wall_to_monotonic.tv_sec + |
00c5fb77 | 1124 | timekeeper.total_sleep_time.tv_sec, |
d9f7217a | 1125 | .tv_nsec = timekeeper.wall_to_monotonic.tv_nsec + |
00c5fb77 | 1126 | timekeeper.total_sleep_time.tv_nsec |
36d47481 | 1127 | }; |
d4f587c6 | 1128 | |
d4f587c6 | 1129 | set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); |
7c3f1a57 | 1130 | } |
c93d89f3 | 1131 | EXPORT_SYMBOL_GPL(getboottime); |
7c3f1a57 | 1132 | |
abb3a4ea JS |
1133 | |
1134 | /** | |
1135 | * get_monotonic_boottime - Returns monotonic time since boot | |
1136 | * @ts: pointer to the timespec to be set | |
1137 | * | |
1138 | * Returns the monotonic time since boot in a timespec. | |
1139 | * | |
1140 | * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also | |
1141 | * includes the time spent in suspend. | |
1142 | */ | |
1143 | void get_monotonic_boottime(struct timespec *ts) | |
1144 | { | |
1145 | struct timespec tomono, sleep; | |
1146 | unsigned int seq; | |
1147 | s64 nsecs; | |
1148 | ||
1149 | WARN_ON(timekeeping_suspended); | |
1150 | ||
1151 | do { | |
70471f2f | 1152 | seq = read_seqbegin(&timekeeper.lock); |
8ff2cb92 | 1153 | *ts = timekeeper.xtime; |
d9f7217a | 1154 | tomono = timekeeper.wall_to_monotonic; |
00c5fb77 | 1155 | sleep = timekeeper.total_sleep_time; |
abb3a4ea JS |
1156 | nsecs = timekeeping_get_ns(); |
1157 | ||
70471f2f | 1158 | } while (read_seqretry(&timekeeper.lock, seq)); |
abb3a4ea JS |
1159 | |
1160 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec, | |
1161 | ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec + nsecs); | |
1162 | } | |
1163 | EXPORT_SYMBOL_GPL(get_monotonic_boottime); | |
1164 | ||
1165 | /** | |
1166 | * ktime_get_boottime - Returns monotonic time since boot in a ktime | |
1167 | * | |
1168 | * Returns the monotonic time since boot in a ktime | |
1169 | * | |
1170 | * This is similar to CLOCK_MONTONIC/ktime_get, but also | |
1171 | * includes the time spent in suspend. | |
1172 | */ | |
1173 | ktime_t ktime_get_boottime(void) | |
1174 | { | |
1175 | struct timespec ts; | |
1176 | ||
1177 | get_monotonic_boottime(&ts); | |
1178 | return timespec_to_ktime(ts); | |
1179 | } | |
1180 | EXPORT_SYMBOL_GPL(ktime_get_boottime); | |
1181 | ||
7c3f1a57 TJ |
1182 | /** |
1183 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
1184 | * @ts: pointer to the timespec to be converted | |
1185 | */ | |
1186 | void monotonic_to_bootbased(struct timespec *ts) | |
1187 | { | |
00c5fb77 | 1188 | *ts = timespec_add(*ts, timekeeper.total_sleep_time); |
7c3f1a57 | 1189 | } |
c93d89f3 | 1190 | EXPORT_SYMBOL_GPL(monotonic_to_bootbased); |
2c6b47de | 1191 | |
17c38b74 JS |
1192 | unsigned long get_seconds(void) |
1193 | { | |
8ff2cb92 | 1194 | return timekeeper.xtime.tv_sec; |
17c38b74 JS |
1195 | } |
1196 | EXPORT_SYMBOL(get_seconds); | |
1197 | ||
da15cfda JS |
1198 | struct timespec __current_kernel_time(void) |
1199 | { | |
8ff2cb92 | 1200 | return timekeeper.xtime; |
da15cfda | 1201 | } |
17c38b74 | 1202 | |
2c6b47de JS |
1203 | struct timespec current_kernel_time(void) |
1204 | { | |
1205 | struct timespec now; | |
1206 | unsigned long seq; | |
1207 | ||
1208 | do { | |
70471f2f | 1209 | seq = read_seqbegin(&timekeeper.lock); |
83f57a11 | 1210 | |
8ff2cb92 | 1211 | now = timekeeper.xtime; |
70471f2f | 1212 | } while (read_seqretry(&timekeeper.lock, seq)); |
2c6b47de JS |
1213 | |
1214 | return now; | |
1215 | } | |
2c6b47de | 1216 | EXPORT_SYMBOL(current_kernel_time); |
da15cfda JS |
1217 | |
1218 | struct timespec get_monotonic_coarse(void) | |
1219 | { | |
1220 | struct timespec now, mono; | |
1221 | unsigned long seq; | |
1222 | ||
1223 | do { | |
70471f2f | 1224 | seq = read_seqbegin(&timekeeper.lock); |
83f57a11 | 1225 | |
8ff2cb92 | 1226 | now = timekeeper.xtime; |
d9f7217a | 1227 | mono = timekeeper.wall_to_monotonic; |
70471f2f | 1228 | } while (read_seqretry(&timekeeper.lock, seq)); |
da15cfda JS |
1229 | |
1230 | set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, | |
1231 | now.tv_nsec + mono.tv_nsec); | |
1232 | return now; | |
1233 | } | |
871cf1e5 TH |
1234 | |
1235 | /* | |
1236 | * The 64-bit jiffies value is not atomic - you MUST NOT read it | |
1237 | * without sampling the sequence number in xtime_lock. | |
1238 | * jiffies is defined in the linker script... | |
1239 | */ | |
1240 | void do_timer(unsigned long ticks) | |
1241 | { | |
1242 | jiffies_64 += ticks; | |
1243 | update_wall_time(); | |
1244 | calc_global_load(ticks); | |
1245 | } | |
48cf76f7 TH |
1246 | |
1247 | /** | |
314ac371 JS |
1248 | * get_xtime_and_monotonic_and_sleep_offset() - get xtime, wall_to_monotonic, |
1249 | * and sleep offsets. | |
48cf76f7 TH |
1250 | * @xtim: pointer to timespec to be set with xtime |
1251 | * @wtom: pointer to timespec to be set with wall_to_monotonic | |
314ac371 | 1252 | * @sleep: pointer to timespec to be set with time in suspend |
48cf76f7 | 1253 | */ |
314ac371 JS |
1254 | void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, |
1255 | struct timespec *wtom, struct timespec *sleep) | |
48cf76f7 TH |
1256 | { |
1257 | unsigned long seq; | |
1258 | ||
1259 | do { | |
70471f2f | 1260 | seq = read_seqbegin(&timekeeper.lock); |
8ff2cb92 | 1261 | *xtim = timekeeper.xtime; |
d9f7217a | 1262 | *wtom = timekeeper.wall_to_monotonic; |
00c5fb77 | 1263 | *sleep = timekeeper.total_sleep_time; |
70471f2f | 1264 | } while (read_seqretry(&timekeeper.lock, seq)); |
48cf76f7 | 1265 | } |
f0af911a | 1266 | |
99ee5315 TG |
1267 | /** |
1268 | * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format | |
1269 | */ | |
1270 | ktime_t ktime_get_monotonic_offset(void) | |
1271 | { | |
1272 | unsigned long seq; | |
1273 | struct timespec wtom; | |
1274 | ||
1275 | do { | |
70471f2f | 1276 | seq = read_seqbegin(&timekeeper.lock); |
d9f7217a | 1277 | wtom = timekeeper.wall_to_monotonic; |
70471f2f JS |
1278 | } while (read_seqretry(&timekeeper.lock, seq)); |
1279 | ||
99ee5315 TG |
1280 | return timespec_to_ktime(wtom); |
1281 | } | |
1282 | ||
f0af911a TH |
1283 | /** |
1284 | * xtime_update() - advances the timekeeping infrastructure | |
1285 | * @ticks: number of ticks, that have elapsed since the last call. | |
1286 | * | |
1287 | * Must be called with interrupts disabled. | |
1288 | */ | |
1289 | void xtime_update(unsigned long ticks) | |
1290 | { | |
1291 | write_seqlock(&xtime_lock); | |
1292 | do_timer(ticks); | |
1293 | write_sequnlock(&xtime_lock); | |
1294 | } |