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Commit | Line | Data |
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8524070b JS |
1 | /* |
2 | * linux/kernel/time/timekeeping.c | |
3 | * | |
4 | * Kernel timekeeping code and accessor functions | |
5 | * | |
6 | * This code was moved from linux/kernel/timer.c. | |
7 | * Please see that file for copyright and history logs. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/interrupt.h> | |
13 | #include <linux/percpu.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/sysdev.h> | |
17 | #include <linux/clocksource.h> | |
18 | #include <linux/jiffies.h> | |
19 | #include <linux/time.h> | |
20 | #include <linux/tick.h> | |
75c5158f | 21 | #include <linux/stop_machine.h> |
8524070b | 22 | |
155ec602 MS |
23 | /* Structure holding internal timekeeping values. */ |
24 | struct timekeeper { | |
25 | /* Current clocksource used for timekeeping. */ | |
26 | struct clocksource *clock; | |
23ce7211 MS |
27 | /* The shift value of the current clocksource. */ |
28 | int shift; | |
155ec602 MS |
29 | |
30 | /* Number of clock cycles in one NTP interval. */ | |
31 | cycle_t cycle_interval; | |
32 | /* Number of clock shifted nano seconds in one NTP interval. */ | |
33 | u64 xtime_interval; | |
34 | /* Raw nano seconds accumulated per NTP interval. */ | |
35 | u32 raw_interval; | |
36 | ||
37 | /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */ | |
38 | u64 xtime_nsec; | |
39 | /* Difference between accumulated time and NTP time in ntp | |
40 | * shifted nano seconds. */ | |
41 | s64 ntp_error; | |
23ce7211 MS |
42 | /* Shift conversion between clock shifted nano seconds and |
43 | * ntp shifted nano seconds. */ | |
44 | int ntp_error_shift; | |
0a544198 MS |
45 | /* NTP adjusted clock multiplier */ |
46 | u32 mult; | |
155ec602 MS |
47 | }; |
48 | ||
49 | struct timekeeper timekeeper; | |
50 | ||
51 | /** | |
52 | * timekeeper_setup_internals - Set up internals to use clocksource clock. | |
53 | * | |
54 | * @clock: Pointer to clocksource. | |
55 | * | |
56 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment | |
57 | * pair and interval request. | |
58 | * | |
59 | * Unless you're the timekeeping code, you should not be using this! | |
60 | */ | |
61 | static void timekeeper_setup_internals(struct clocksource *clock) | |
62 | { | |
63 | cycle_t interval; | |
64 | u64 tmp; | |
65 | ||
66 | timekeeper.clock = clock; | |
67 | clock->cycle_last = clock->read(clock); | |
68 | ||
69 | /* Do the ns -> cycle conversion first, using original mult */ | |
70 | tmp = NTP_INTERVAL_LENGTH; | |
71 | tmp <<= clock->shift; | |
0a544198 MS |
72 | tmp += clock->mult/2; |
73 | do_div(tmp, clock->mult); | |
155ec602 MS |
74 | if (tmp == 0) |
75 | tmp = 1; | |
76 | ||
77 | interval = (cycle_t) tmp; | |
78 | timekeeper.cycle_interval = interval; | |
79 | ||
80 | /* Go back from cycles -> shifted ns */ | |
81 | timekeeper.xtime_interval = (u64) interval * clock->mult; | |
82 | timekeeper.raw_interval = | |
0a544198 | 83 | ((u64) interval * clock->mult) >> clock->shift; |
155ec602 MS |
84 | |
85 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 86 | timekeeper.shift = clock->shift; |
155ec602 MS |
87 | |
88 | timekeeper.ntp_error = 0; | |
23ce7211 | 89 | timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
0a544198 MS |
90 | |
91 | /* | |
92 | * The timekeeper keeps its own mult values for the currently | |
93 | * active clocksource. These value will be adjusted via NTP | |
94 | * to counteract clock drifting. | |
95 | */ | |
96 | timekeeper.mult = clock->mult; | |
155ec602 | 97 | } |
8524070b | 98 | |
2ba2a305 MS |
99 | /* Timekeeper helper functions. */ |
100 | static inline s64 timekeeping_get_ns(void) | |
101 | { | |
102 | cycle_t cycle_now, cycle_delta; | |
103 | struct clocksource *clock; | |
104 | ||
105 | /* read clocksource: */ | |
106 | clock = timekeeper.clock; | |
107 | cycle_now = clock->read(clock); | |
108 | ||
109 | /* calculate the delta since the last update_wall_time: */ | |
110 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
111 | ||
112 | /* return delta convert to nanoseconds using ntp adjusted mult. */ | |
113 | return clocksource_cyc2ns(cycle_delta, timekeeper.mult, | |
114 | timekeeper.shift); | |
115 | } | |
116 | ||
117 | static inline s64 timekeeping_get_ns_raw(void) | |
118 | { | |
119 | cycle_t cycle_now, cycle_delta; | |
120 | struct clocksource *clock; | |
121 | ||
122 | /* read clocksource: */ | |
123 | clock = timekeeper.clock; | |
124 | cycle_now = clock->read(clock); | |
125 | ||
126 | /* calculate the delta since the last update_wall_time: */ | |
127 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
128 | ||
129 | /* return delta convert to nanoseconds using ntp adjusted mult. */ | |
130 | return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); | |
131 | } | |
132 | ||
8524070b JS |
133 | /* |
134 | * This read-write spinlock protects us from races in SMP while | |
dce48a84 | 135 | * playing with xtime. |
8524070b | 136 | */ |
ba2a631b | 137 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); |
8524070b JS |
138 | |
139 | ||
140 | /* | |
141 | * The current time | |
142 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected | |
143 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged | |
144 | * at zero at system boot time, so wall_to_monotonic will be negative, | |
145 | * however, we will ALWAYS keep the tv_nsec part positive so we can use | |
146 | * the usual normalization. | |
7c3f1a57 TJ |
147 | * |
148 | * wall_to_monotonic is moved after resume from suspend for the monotonic | |
149 | * time not to jump. We need to add total_sleep_time to wall_to_monotonic | |
150 | * to get the real boot based time offset. | |
151 | * | |
152 | * - wall_to_monotonic is no longer the boot time, getboottime must be | |
153 | * used instead. | |
8524070b JS |
154 | */ |
155 | struct timespec xtime __attribute__ ((aligned (16))); | |
156 | struct timespec wall_to_monotonic __attribute__ ((aligned (16))); | |
d4f587c6 | 157 | static struct timespec total_sleep_time; |
8524070b | 158 | |
155ec602 MS |
159 | /* |
160 | * The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. | |
161 | */ | |
162 | struct timespec raw_time; | |
163 | ||
1c5745aa TG |
164 | /* flag for if timekeeping is suspended */ |
165 | int __read_mostly timekeeping_suspended; | |
166 | ||
17c38b74 | 167 | static struct timespec xtime_cache __attribute__ ((aligned (16))); |
1001d0a9 | 168 | void update_xtime_cache(u64 nsec) |
17c38b74 JS |
169 | { |
170 | xtime_cache = xtime; | |
171 | timespec_add_ns(&xtime_cache, nsec); | |
172 | } | |
17c38b74 | 173 | |
31089c13 JS |
174 | /* must hold xtime_lock */ |
175 | void timekeeping_leap_insert(int leapsecond) | |
176 | { | |
177 | xtime.tv_sec += leapsecond; | |
178 | wall_to_monotonic.tv_sec -= leapsecond; | |
155ec602 | 179 | update_vsyscall(&xtime, timekeeper.clock); |
31089c13 | 180 | } |
8524070b JS |
181 | |
182 | #ifdef CONFIG_GENERIC_TIME | |
75c5158f | 183 | |
8524070b | 184 | /** |
155ec602 | 185 | * timekeeping_forward_now - update clock to the current time |
8524070b | 186 | * |
9a055117 RZ |
187 | * Forward the current clock to update its state since the last call to |
188 | * update_wall_time(). This is useful before significant clock changes, | |
189 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 190 | */ |
155ec602 | 191 | static void timekeeping_forward_now(void) |
8524070b JS |
192 | { |
193 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 194 | struct clocksource *clock; |
9a055117 | 195 | s64 nsec; |
8524070b | 196 | |
155ec602 | 197 | clock = timekeeper.clock; |
a0f7d48b | 198 | cycle_now = clock->read(clock); |
8524070b | 199 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 200 | clock->cycle_last = cycle_now; |
8524070b | 201 | |
0a544198 MS |
202 | nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult, |
203 | timekeeper.shift); | |
7d27558c JS |
204 | |
205 | /* If arch requires, add in gettimeoffset() */ | |
206 | nsec += arch_gettimeoffset(); | |
207 | ||
9a055117 | 208 | timespec_add_ns(&xtime, nsec); |
2d42244a | 209 | |
0a544198 | 210 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
155ec602 | 211 | timespec_add_ns(&raw_time, nsec); |
8524070b JS |
212 | } |
213 | ||
214 | /** | |
efd9ac86 | 215 | * getnstimeofday - Returns the time of day in a timespec |
8524070b JS |
216 | * @ts: pointer to the timespec to be set |
217 | * | |
efd9ac86 | 218 | * Returns the time of day in a timespec. |
8524070b | 219 | */ |
efd9ac86 | 220 | void getnstimeofday(struct timespec *ts) |
8524070b JS |
221 | { |
222 | unsigned long seq; | |
223 | s64 nsecs; | |
224 | ||
1c5745aa TG |
225 | WARN_ON(timekeeping_suspended); |
226 | ||
8524070b JS |
227 | do { |
228 | seq = read_seqbegin(&xtime_lock); | |
229 | ||
230 | *ts = xtime; | |
2ba2a305 | 231 | nsecs = timekeeping_get_ns(); |
8524070b | 232 | |
7d27558c JS |
233 | /* If arch requires, add in gettimeoffset() */ |
234 | nsecs += arch_gettimeoffset(); | |
235 | ||
8524070b JS |
236 | } while (read_seqretry(&xtime_lock, seq)); |
237 | ||
238 | timespec_add_ns(ts, nsecs); | |
239 | } | |
240 | ||
8524070b JS |
241 | EXPORT_SYMBOL(getnstimeofday); |
242 | ||
951ed4d3 MS |
243 | ktime_t ktime_get(void) |
244 | { | |
951ed4d3 MS |
245 | unsigned int seq; |
246 | s64 secs, nsecs; | |
247 | ||
248 | WARN_ON(timekeeping_suspended); | |
249 | ||
250 | do { | |
251 | seq = read_seqbegin(&xtime_lock); | |
252 | secs = xtime.tv_sec + wall_to_monotonic.tv_sec; | |
253 | nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec; | |
2ba2a305 | 254 | nsecs += timekeeping_get_ns(); |
951ed4d3 MS |
255 | |
256 | } while (read_seqretry(&xtime_lock, seq)); | |
257 | /* | |
258 | * Use ktime_set/ktime_add_ns to create a proper ktime on | |
259 | * 32-bit architectures without CONFIG_KTIME_SCALAR. | |
260 | */ | |
261 | return ktime_add_ns(ktime_set(secs, 0), nsecs); | |
262 | } | |
263 | EXPORT_SYMBOL_GPL(ktime_get); | |
264 | ||
265 | /** | |
266 | * ktime_get_ts - get the monotonic clock in timespec format | |
267 | * @ts: pointer to timespec variable | |
268 | * | |
269 | * The function calculates the monotonic clock from the realtime | |
270 | * clock and the wall_to_monotonic offset and stores the result | |
271 | * in normalized timespec format in the variable pointed to by @ts. | |
272 | */ | |
273 | void ktime_get_ts(struct timespec *ts) | |
274 | { | |
951ed4d3 MS |
275 | struct timespec tomono; |
276 | unsigned int seq; | |
277 | s64 nsecs; | |
278 | ||
279 | WARN_ON(timekeeping_suspended); | |
280 | ||
281 | do { | |
282 | seq = read_seqbegin(&xtime_lock); | |
283 | *ts = xtime; | |
284 | tomono = wall_to_monotonic; | |
2ba2a305 | 285 | nsecs = timekeeping_get_ns(); |
951ed4d3 MS |
286 | |
287 | } while (read_seqretry(&xtime_lock, seq)); | |
288 | ||
289 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
290 | ts->tv_nsec + tomono.tv_nsec + nsecs); | |
291 | } | |
292 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
293 | ||
8524070b JS |
294 | /** |
295 | * do_gettimeofday - Returns the time of day in a timeval | |
296 | * @tv: pointer to the timeval to be set | |
297 | * | |
efd9ac86 | 298 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b JS |
299 | */ |
300 | void do_gettimeofday(struct timeval *tv) | |
301 | { | |
302 | struct timespec now; | |
303 | ||
efd9ac86 | 304 | getnstimeofday(&now); |
8524070b JS |
305 | tv->tv_sec = now.tv_sec; |
306 | tv->tv_usec = now.tv_nsec/1000; | |
307 | } | |
308 | ||
309 | EXPORT_SYMBOL(do_gettimeofday); | |
310 | /** | |
311 | * do_settimeofday - Sets the time of day | |
312 | * @tv: pointer to the timespec variable containing the new time | |
313 | * | |
314 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
315 | */ | |
316 | int do_settimeofday(struct timespec *tv) | |
317 | { | |
9a055117 | 318 | struct timespec ts_delta; |
8524070b | 319 | unsigned long flags; |
8524070b JS |
320 | |
321 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
322 | return -EINVAL; | |
323 | ||
324 | write_seqlock_irqsave(&xtime_lock, flags); | |
325 | ||
155ec602 | 326 | timekeeping_forward_now(); |
9a055117 RZ |
327 | |
328 | ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec; | |
329 | ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec; | |
330 | wall_to_monotonic = timespec_sub(wall_to_monotonic, ts_delta); | |
8524070b | 331 | |
9a055117 | 332 | xtime = *tv; |
8524070b | 333 | |
1001d0a9 | 334 | update_xtime_cache(0); |
8524070b | 335 | |
155ec602 | 336 | timekeeper.ntp_error = 0; |
8524070b JS |
337 | ntp_clear(); |
338 | ||
155ec602 | 339 | update_vsyscall(&xtime, timekeeper.clock); |
8524070b JS |
340 | |
341 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
342 | ||
343 | /* signal hrtimers about time change */ | |
344 | clock_was_set(); | |
345 | ||
346 | return 0; | |
347 | } | |
348 | ||
349 | EXPORT_SYMBOL(do_settimeofday); | |
350 | ||
351 | /** | |
352 | * change_clocksource - Swaps clocksources if a new one is available | |
353 | * | |
354 | * Accumulates current time interval and initializes new clocksource | |
355 | */ | |
75c5158f | 356 | static int change_clocksource(void *data) |
8524070b | 357 | { |
4614e6ad | 358 | struct clocksource *new, *old; |
8524070b | 359 | |
75c5158f | 360 | new = (struct clocksource *) data; |
8524070b | 361 | |
155ec602 | 362 | timekeeping_forward_now(); |
75c5158f MS |
363 | if (!new->enable || new->enable(new) == 0) { |
364 | old = timekeeper.clock; | |
365 | timekeeper_setup_internals(new); | |
366 | if (old->disable) | |
367 | old->disable(old); | |
368 | } | |
369 | return 0; | |
370 | } | |
8524070b | 371 | |
75c5158f MS |
372 | /** |
373 | * timekeeping_notify - Install a new clock source | |
374 | * @clock: pointer to the clock source | |
375 | * | |
376 | * This function is called from clocksource.c after a new, better clock | |
377 | * source has been registered. The caller holds the clocksource_mutex. | |
378 | */ | |
379 | void timekeeping_notify(struct clocksource *clock) | |
380 | { | |
381 | if (timekeeper.clock == clock) | |
4614e6ad | 382 | return; |
75c5158f | 383 | stop_machine(change_clocksource, clock, NULL); |
8524070b | 384 | tick_clock_notify(); |
8524070b | 385 | } |
75c5158f | 386 | |
a40f262c | 387 | #else /* GENERIC_TIME */ |
75c5158f | 388 | |
155ec602 | 389 | static inline void timekeeping_forward_now(void) { } |
a40f262c TG |
390 | |
391 | /** | |
392 | * ktime_get - get the monotonic time in ktime_t format | |
393 | * | |
394 | * returns the time in ktime_t format | |
395 | */ | |
396 | ktime_t ktime_get(void) | |
397 | { | |
398 | struct timespec now; | |
399 | ||
400 | ktime_get_ts(&now); | |
401 | ||
402 | return timespec_to_ktime(now); | |
403 | } | |
404 | EXPORT_SYMBOL_GPL(ktime_get); | |
405 | ||
406 | /** | |
407 | * ktime_get_ts - get the monotonic clock in timespec format | |
408 | * @ts: pointer to timespec variable | |
409 | * | |
410 | * The function calculates the monotonic clock from the realtime | |
411 | * clock and the wall_to_monotonic offset and stores the result | |
412 | * in normalized timespec format in the variable pointed to by @ts. | |
413 | */ | |
414 | void ktime_get_ts(struct timespec *ts) | |
415 | { | |
416 | struct timespec tomono; | |
417 | unsigned long seq; | |
418 | ||
419 | do { | |
420 | seq = read_seqbegin(&xtime_lock); | |
421 | getnstimeofday(ts); | |
422 | tomono = wall_to_monotonic; | |
423 | ||
424 | } while (read_seqretry(&xtime_lock, seq)); | |
425 | ||
426 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
427 | ts->tv_nsec + tomono.tv_nsec); | |
428 | } | |
429 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
75c5158f | 430 | |
a40f262c TG |
431 | #endif /* !GENERIC_TIME */ |
432 | ||
433 | /** | |
434 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
435 | * | |
436 | * returns the time in ktime_t format | |
437 | */ | |
438 | ktime_t ktime_get_real(void) | |
439 | { | |
440 | struct timespec now; | |
441 | ||
442 | getnstimeofday(&now); | |
443 | ||
444 | return timespec_to_ktime(now); | |
445 | } | |
446 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
8524070b | 447 | |
2d42244a JS |
448 | /** |
449 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
450 | * @ts: pointer to the timespec to be set | |
451 | * | |
452 | * Returns the raw monotonic time (completely un-modified by ntp) | |
453 | */ | |
454 | void getrawmonotonic(struct timespec *ts) | |
455 | { | |
456 | unsigned long seq; | |
457 | s64 nsecs; | |
2d42244a JS |
458 | |
459 | do { | |
460 | seq = read_seqbegin(&xtime_lock); | |
2ba2a305 | 461 | nsecs = timekeeping_get_ns_raw(); |
155ec602 | 462 | *ts = raw_time; |
2d42244a JS |
463 | |
464 | } while (read_seqretry(&xtime_lock, seq)); | |
465 | ||
466 | timespec_add_ns(ts, nsecs); | |
467 | } | |
468 | EXPORT_SYMBOL(getrawmonotonic); | |
469 | ||
470 | ||
8524070b | 471 | /** |
cf4fc6cb | 472 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 473 | */ |
cf4fc6cb | 474 | int timekeeping_valid_for_hres(void) |
8524070b JS |
475 | { |
476 | unsigned long seq; | |
477 | int ret; | |
478 | ||
479 | do { | |
480 | seq = read_seqbegin(&xtime_lock); | |
481 | ||
155ec602 | 482 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
8524070b JS |
483 | |
484 | } while (read_seqretry(&xtime_lock, seq)); | |
485 | ||
486 | return ret; | |
487 | } | |
488 | ||
489 | /** | |
d4f587c6 | 490 | * read_persistent_clock - Return time from the persistent clock. |
8524070b JS |
491 | * |
492 | * Weak dummy function for arches that do not yet support it. | |
d4f587c6 MS |
493 | * Reads the time from the battery backed persistent clock. |
494 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
8524070b JS |
495 | * |
496 | * XXX - Do be sure to remove it once all arches implement it. | |
497 | */ | |
d4f587c6 | 498 | void __attribute__((weak)) read_persistent_clock(struct timespec *ts) |
8524070b | 499 | { |
d4f587c6 MS |
500 | ts->tv_sec = 0; |
501 | ts->tv_nsec = 0; | |
8524070b JS |
502 | } |
503 | ||
23970e38 MS |
504 | /** |
505 | * read_boot_clock - Return time of the system start. | |
506 | * | |
507 | * Weak dummy function for arches that do not yet support it. | |
508 | * Function to read the exact time the system has been started. | |
509 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
510 | * | |
511 | * XXX - Do be sure to remove it once all arches implement it. | |
512 | */ | |
513 | void __attribute__((weak)) read_boot_clock(struct timespec *ts) | |
514 | { | |
515 | ts->tv_sec = 0; | |
516 | ts->tv_nsec = 0; | |
517 | } | |
518 | ||
8524070b JS |
519 | /* |
520 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
521 | */ | |
522 | void __init timekeeping_init(void) | |
523 | { | |
155ec602 | 524 | struct clocksource *clock; |
8524070b | 525 | unsigned long flags; |
23970e38 | 526 | struct timespec now, boot; |
d4f587c6 MS |
527 | |
528 | read_persistent_clock(&now); | |
23970e38 | 529 | read_boot_clock(&boot); |
8524070b JS |
530 | |
531 | write_seqlock_irqsave(&xtime_lock, flags); | |
532 | ||
7dffa3c6 | 533 | ntp_init(); |
8524070b | 534 | |
f1b82746 | 535 | clock = clocksource_default_clock(); |
a0f7d48b MS |
536 | if (clock->enable) |
537 | clock->enable(clock); | |
155ec602 | 538 | timekeeper_setup_internals(clock); |
8524070b | 539 | |
d4f587c6 MS |
540 | xtime.tv_sec = now.tv_sec; |
541 | xtime.tv_nsec = now.tv_nsec; | |
155ec602 MS |
542 | raw_time.tv_sec = 0; |
543 | raw_time.tv_nsec = 0; | |
23970e38 MS |
544 | if (boot.tv_sec == 0 && boot.tv_nsec == 0) { |
545 | boot.tv_sec = xtime.tv_sec; | |
546 | boot.tv_nsec = xtime.tv_nsec; | |
547 | } | |
8524070b | 548 | set_normalized_timespec(&wall_to_monotonic, |
23970e38 | 549 | -boot.tv_sec, -boot.tv_nsec); |
1001d0a9 | 550 | update_xtime_cache(0); |
d4f587c6 MS |
551 | total_sleep_time.tv_sec = 0; |
552 | total_sleep_time.tv_nsec = 0; | |
8524070b JS |
553 | write_sequnlock_irqrestore(&xtime_lock, flags); |
554 | } | |
555 | ||
8524070b | 556 | /* time in seconds when suspend began */ |
d4f587c6 | 557 | static struct timespec timekeeping_suspend_time; |
8524070b JS |
558 | |
559 | /** | |
560 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
561 | * @dev: unused | |
562 | * | |
563 | * This is for the generic clocksource timekeeping. | |
564 | * xtime/wall_to_monotonic/jiffies/etc are | |
565 | * still managed by arch specific suspend/resume code. | |
566 | */ | |
567 | static int timekeeping_resume(struct sys_device *dev) | |
568 | { | |
569 | unsigned long flags; | |
d4f587c6 MS |
570 | struct timespec ts; |
571 | ||
572 | read_persistent_clock(&ts); | |
8524070b | 573 | |
d10ff3fb TG |
574 | clocksource_resume(); |
575 | ||
8524070b JS |
576 | write_seqlock_irqsave(&xtime_lock, flags); |
577 | ||
d4f587c6 MS |
578 | if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { |
579 | ts = timespec_sub(ts, timekeeping_suspend_time); | |
580 | xtime = timespec_add_safe(xtime, ts); | |
581 | wall_to_monotonic = timespec_sub(wall_to_monotonic, ts); | |
582 | total_sleep_time = timespec_add_safe(total_sleep_time, ts); | |
8524070b | 583 | } |
1001d0a9 | 584 | update_xtime_cache(0); |
8524070b | 585 | /* re-base the last cycle value */ |
155ec602 MS |
586 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
587 | timekeeper.ntp_error = 0; | |
8524070b JS |
588 | timekeeping_suspended = 0; |
589 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
590 | ||
591 | touch_softlockup_watchdog(); | |
592 | ||
593 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); | |
594 | ||
595 | /* Resume hrtimers */ | |
596 | hres_timers_resume(); | |
597 | ||
598 | return 0; | |
599 | } | |
600 | ||
601 | static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) | |
602 | { | |
603 | unsigned long flags; | |
604 | ||
d4f587c6 | 605 | read_persistent_clock(&timekeeping_suspend_time); |
3be90950 | 606 | |
8524070b | 607 | write_seqlock_irqsave(&xtime_lock, flags); |
155ec602 | 608 | timekeeping_forward_now(); |
8524070b | 609 | timekeeping_suspended = 1; |
8524070b JS |
610 | write_sequnlock_irqrestore(&xtime_lock, flags); |
611 | ||
612 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
613 | ||
614 | return 0; | |
615 | } | |
616 | ||
617 | /* sysfs resume/suspend bits for timekeeping */ | |
618 | static struct sysdev_class timekeeping_sysclass = { | |
af5ca3f4 | 619 | .name = "timekeeping", |
8524070b JS |
620 | .resume = timekeeping_resume, |
621 | .suspend = timekeeping_suspend, | |
8524070b JS |
622 | }; |
623 | ||
624 | static struct sys_device device_timer = { | |
625 | .id = 0, | |
626 | .cls = &timekeeping_sysclass, | |
627 | }; | |
628 | ||
629 | static int __init timekeeping_init_device(void) | |
630 | { | |
631 | int error = sysdev_class_register(&timekeeping_sysclass); | |
632 | if (!error) | |
633 | error = sysdev_register(&device_timer); | |
634 | return error; | |
635 | } | |
636 | ||
637 | device_initcall(timekeeping_init_device); | |
638 | ||
639 | /* | |
640 | * If the error is already larger, we look ahead even further | |
641 | * to compensate for late or lost adjustments. | |
642 | */ | |
155ec602 | 643 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
8524070b JS |
644 | s64 *offset) |
645 | { | |
646 | s64 tick_error, i; | |
647 | u32 look_ahead, adj; | |
648 | s32 error2, mult; | |
649 | ||
650 | /* | |
651 | * Use the current error value to determine how much to look ahead. | |
652 | * The larger the error the slower we adjust for it to avoid problems | |
653 | * with losing too many ticks, otherwise we would overadjust and | |
654 | * produce an even larger error. The smaller the adjustment the | |
655 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 656 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b JS |
657 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
658 | */ | |
155ec602 | 659 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b JS |
660 | error2 = abs(error2); |
661 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
662 | error2 >>= 2; | |
663 | ||
664 | /* | |
665 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
666 | * remove the single look ahead already included in the error. | |
667 | */ | |
23ce7211 | 668 | tick_error = tick_length >> (timekeeper.ntp_error_shift + 1); |
155ec602 | 669 | tick_error -= timekeeper.xtime_interval >> 1; |
8524070b JS |
670 | error = ((error - tick_error) >> look_ahead) + tick_error; |
671 | ||
672 | /* Finally calculate the adjustment shift value. */ | |
673 | i = *interval; | |
674 | mult = 1; | |
675 | if (error < 0) { | |
676 | error = -error; | |
677 | *interval = -*interval; | |
678 | *offset = -*offset; | |
679 | mult = -1; | |
680 | } | |
681 | for (adj = 0; error > i; adj++) | |
682 | error >>= 1; | |
683 | ||
684 | *interval <<= adj; | |
685 | *offset <<= adj; | |
686 | return mult << adj; | |
687 | } | |
688 | ||
689 | /* | |
690 | * Adjust the multiplier to reduce the error value, | |
691 | * this is optimized for the most common adjustments of -1,0,1, | |
692 | * for other values we can do a bit more work. | |
693 | */ | |
155ec602 | 694 | static void timekeeping_adjust(s64 offset) |
8524070b | 695 | { |
155ec602 | 696 | s64 error, interval = timekeeper.cycle_interval; |
8524070b JS |
697 | int adj; |
698 | ||
23ce7211 | 699 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
8524070b JS |
700 | if (error > interval) { |
701 | error >>= 2; | |
702 | if (likely(error <= interval)) | |
703 | adj = 1; | |
704 | else | |
155ec602 | 705 | adj = timekeeping_bigadjust(error, &interval, &offset); |
8524070b JS |
706 | } else if (error < -interval) { |
707 | error >>= 2; | |
708 | if (likely(error >= -interval)) { | |
709 | adj = -1; | |
710 | interval = -interval; | |
711 | offset = -offset; | |
712 | } else | |
155ec602 | 713 | adj = timekeeping_bigadjust(error, &interval, &offset); |
8524070b JS |
714 | } else |
715 | return; | |
716 | ||
0a544198 | 717 | timekeeper.mult += adj; |
155ec602 MS |
718 | timekeeper.xtime_interval += interval; |
719 | timekeeper.xtime_nsec -= offset; | |
720 | timekeeper.ntp_error -= (interval - offset) << | |
23ce7211 | 721 | timekeeper.ntp_error_shift; |
8524070b JS |
722 | } |
723 | ||
724 | /** | |
725 | * update_wall_time - Uses the current clocksource to increment the wall time | |
726 | * | |
727 | * Called from the timer interrupt, must hold a write on xtime_lock. | |
728 | */ | |
729 | void update_wall_time(void) | |
730 | { | |
155ec602 | 731 | struct clocksource *clock; |
8524070b | 732 | cycle_t offset; |
23ce7211 | 733 | u64 nsecs; |
8524070b JS |
734 | |
735 | /* Make sure we're fully resumed: */ | |
736 | if (unlikely(timekeeping_suspended)) | |
737 | return; | |
738 | ||
155ec602 | 739 | clock = timekeeper.clock; |
8524070b | 740 | #ifdef CONFIG_GENERIC_TIME |
a0f7d48b | 741 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; |
8524070b | 742 | #else |
155ec602 | 743 | offset = timekeeper.cycle_interval; |
8524070b | 744 | #endif |
23ce7211 | 745 | timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift; |
8524070b JS |
746 | |
747 | /* normally this loop will run just once, however in the | |
748 | * case of lost or late ticks, it will accumulate correctly. | |
749 | */ | |
155ec602 | 750 | while (offset >= timekeeper.cycle_interval) { |
23ce7211 | 751 | u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; |
155ec602 | 752 | |
8524070b | 753 | /* accumulate one interval */ |
155ec602 MS |
754 | offset -= timekeeper.cycle_interval; |
755 | clock->cycle_last += timekeeper.cycle_interval; | |
8524070b | 756 | |
155ec602 MS |
757 | timekeeper.xtime_nsec += timekeeper.xtime_interval; |
758 | if (timekeeper.xtime_nsec >= nsecps) { | |
759 | timekeeper.xtime_nsec -= nsecps; | |
8524070b JS |
760 | xtime.tv_sec++; |
761 | second_overflow(); | |
762 | } | |
763 | ||
155ec602 MS |
764 | raw_time.tv_nsec += timekeeper.raw_interval; |
765 | if (raw_time.tv_nsec >= NSEC_PER_SEC) { | |
766 | raw_time.tv_nsec -= NSEC_PER_SEC; | |
767 | raw_time.tv_sec++; | |
2d42244a JS |
768 | } |
769 | ||
8524070b | 770 | /* accumulate error between NTP and clock interval */ |
155ec602 MS |
771 | timekeeper.ntp_error += tick_length; |
772 | timekeeper.ntp_error -= timekeeper.xtime_interval << | |
23ce7211 | 773 | timekeeper.ntp_error_shift; |
8524070b JS |
774 | } |
775 | ||
776 | /* correct the clock when NTP error is too big */ | |
155ec602 | 777 | timekeeping_adjust(offset); |
8524070b | 778 | |
6c9bacb4 JS |
779 | /* |
780 | * Since in the loop above, we accumulate any amount of time | |
781 | * in xtime_nsec over a second into xtime.tv_sec, its possible for | |
782 | * xtime_nsec to be fairly small after the loop. Further, if we're | |
155ec602 | 783 | * slightly speeding the clocksource up in timekeeping_adjust(), |
6c9bacb4 JS |
784 | * its possible the required corrective factor to xtime_nsec could |
785 | * cause it to underflow. | |
786 | * | |
787 | * Now, we cannot simply roll the accumulated second back, since | |
788 | * the NTP subsystem has been notified via second_overflow. So | |
789 | * instead we push xtime_nsec forward by the amount we underflowed, | |
790 | * and add that amount into the error. | |
791 | * | |
792 | * We'll correct this error next time through this function, when | |
793 | * xtime_nsec is not as small. | |
794 | */ | |
155ec602 MS |
795 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { |
796 | s64 neg = -(s64)timekeeper.xtime_nsec; | |
797 | timekeeper.xtime_nsec = 0; | |
23ce7211 | 798 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; |
6c9bacb4 JS |
799 | } |
800 | ||
5cd1c9c5 RZ |
801 | /* store full nanoseconds into xtime after rounding it up and |
802 | * add the remainder to the error difference. | |
803 | */ | |
23ce7211 MS |
804 | xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1; |
805 | timekeeper.xtime_nsec -= (s64) xtime.tv_nsec << timekeeper.shift; | |
806 | timekeeper.ntp_error += timekeeper.xtime_nsec << | |
807 | timekeeper.ntp_error_shift; | |
8524070b | 808 | |
0a544198 | 809 | nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift); |
155ec602 | 810 | update_xtime_cache(nsecs); |
17c38b74 | 811 | |
8524070b | 812 | /* check to see if there is a new clocksource to use */ |
155ec602 | 813 | update_vsyscall(&xtime, timekeeper.clock); |
8524070b | 814 | } |
7c3f1a57 TJ |
815 | |
816 | /** | |
817 | * getboottime - Return the real time of system boot. | |
818 | * @ts: pointer to the timespec to be set | |
819 | * | |
820 | * Returns the time of day in a timespec. | |
821 | * | |
822 | * This is based on the wall_to_monotonic offset and the total suspend | |
823 | * time. Calls to settimeofday will affect the value returned (which | |
824 | * basically means that however wrong your real time clock is at boot time, | |
825 | * you get the right time here). | |
826 | */ | |
827 | void getboottime(struct timespec *ts) | |
828 | { | |
36d47481 HS |
829 | struct timespec boottime = { |
830 | .tv_sec = wall_to_monotonic.tv_sec + total_sleep_time.tv_sec, | |
831 | .tv_nsec = wall_to_monotonic.tv_nsec + total_sleep_time.tv_nsec | |
832 | }; | |
d4f587c6 | 833 | |
d4f587c6 | 834 | set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); |
7c3f1a57 TJ |
835 | } |
836 | ||
837 | /** | |
838 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
839 | * @ts: pointer to the timespec to be converted | |
840 | */ | |
841 | void monotonic_to_bootbased(struct timespec *ts) | |
842 | { | |
d4f587c6 | 843 | *ts = timespec_add_safe(*ts, total_sleep_time); |
7c3f1a57 | 844 | } |
2c6b47de | 845 | |
17c38b74 JS |
846 | unsigned long get_seconds(void) |
847 | { | |
848 | return xtime_cache.tv_sec; | |
849 | } | |
850 | EXPORT_SYMBOL(get_seconds); | |
851 | ||
da15cfda JS |
852 | struct timespec __current_kernel_time(void) |
853 | { | |
854 | return xtime_cache; | |
855 | } | |
17c38b74 | 856 | |
2c6b47de JS |
857 | struct timespec current_kernel_time(void) |
858 | { | |
859 | struct timespec now; | |
860 | unsigned long seq; | |
861 | ||
862 | do { | |
863 | seq = read_seqbegin(&xtime_lock); | |
864 | ||
17c38b74 | 865 | now = xtime_cache; |
2c6b47de JS |
866 | } while (read_seqretry(&xtime_lock, seq)); |
867 | ||
868 | return now; | |
869 | } | |
2c6b47de | 870 | EXPORT_SYMBOL(current_kernel_time); |
da15cfda JS |
871 | |
872 | struct timespec get_monotonic_coarse(void) | |
873 | { | |
874 | struct timespec now, mono; | |
875 | unsigned long seq; | |
876 | ||
877 | do { | |
878 | seq = read_seqbegin(&xtime_lock); | |
879 | ||
880 | now = xtime_cache; | |
881 | mono = wall_to_monotonic; | |
882 | } while (read_seqretry(&xtime_lock, seq)); | |
883 | ||
884 | set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, | |
885 | now.tv_nsec + mono.tv_nsec); | |
886 | return now; | |
887 | } |