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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. */ | |
42e71e81 | 27 | struct clocksource *clock; |
058892e6 | 28 | /* NTP adjusted clock multiplier */ |
42e71e81 | 29 | u32 mult; |
23ce7211 | 30 | /* The shift value of the current clocksource. */ |
fee84c43 | 31 | u32 shift; |
155ec602 | 32 | /* Number of clock cycles in one NTP interval. */ |
42e71e81 | 33 | cycle_t cycle_interval; |
155ec602 | 34 | /* Number of clock shifted nano seconds in one NTP interval. */ |
42e71e81 | 35 | u64 xtime_interval; |
a386b5af | 36 | /* shifted nano seconds left over when rounding cycle_interval */ |
42e71e81 | 37 | s64 xtime_remainder; |
155ec602 | 38 | /* Raw nano seconds accumulated per NTP interval. */ |
42e71e81 | 39 | u32 raw_interval; |
155ec602 | 40 | |
1e75fa8b JS |
41 | /* Current CLOCK_REALTIME time in seconds */ |
42 | u64 xtime_sec; | |
43 | /* Clock shifted nano seconds */ | |
42e71e81 | 44 | u64 xtime_nsec; |
1e75fa8b | 45 | |
155ec602 MS |
46 | /* Difference between accumulated time and NTP time in ntp |
47 | * shifted nano seconds. */ | |
42e71e81 | 48 | s64 ntp_error; |
23ce7211 MS |
49 | /* Shift conversion between clock shifted nano seconds and |
50 | * ntp shifted nano seconds. */ | |
fee84c43 | 51 | u32 ntp_error_shift; |
00c5fb77 | 52 | |
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 | */ | |
42e71e81 | 67 | struct timespec wall_to_monotonic; |
00c5fb77 | 68 | /* time spent in suspend */ |
42e71e81 | 69 | struct timespec total_sleep_time; |
01f71b47 | 70 | /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */ |
42e71e81 | 71 | struct timespec raw_time; |
5b9fe759 | 72 | /* Offset clock monotonic -> clock realtime */ |
42e71e81 | 73 | ktime_t offs_real; |
5b9fe759 | 74 | /* Offset clock monotonic -> clock boottime */ |
42e71e81 | 75 | ktime_t offs_boot; |
70471f2f | 76 | /* Seqlock for all timekeeper values */ |
42e71e81 | 77 | seqlock_t lock; |
155ec602 MS |
78 | }; |
79 | ||
afa14e7c | 80 | static struct timekeeper timekeeper; |
155ec602 | 81 | |
8fcce546 JS |
82 | /* |
83 | * This read-write spinlock protects us from races in SMP while | |
84 | * playing with xtime. | |
85 | */ | |
86 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); | |
87 | ||
8fcce546 JS |
88 | /* flag for if timekeeping is suspended */ |
89 | int __read_mostly timekeeping_suspended; | |
90 | ||
1e75fa8b JS |
91 | static inline void tk_normalize_xtime(struct timekeeper *tk) |
92 | { | |
93 | while (tk->xtime_nsec >= ((u64)NSEC_PER_SEC << tk->shift)) { | |
94 | tk->xtime_nsec -= (u64)NSEC_PER_SEC << tk->shift; | |
95 | tk->xtime_sec++; | |
96 | } | |
97 | } | |
98 | ||
99 | static struct timespec tk_xtime(struct timekeeper *tk) | |
100 | { | |
101 | struct timespec ts; | |
102 | ||
103 | ts.tv_sec = tk->xtime_sec; | |
104 | ts.tv_nsec = (long)(tk->xtime_nsec >> tk->shift); | |
105 | return ts; | |
106 | } | |
8fcce546 | 107 | |
1e75fa8b JS |
108 | static void tk_set_xtime(struct timekeeper *tk, const struct timespec *ts) |
109 | { | |
110 | tk->xtime_sec = ts->tv_sec; | |
111 | tk->xtime_nsec = ts->tv_nsec << tk->shift; | |
112 | } | |
113 | ||
114 | static void tk_xtime_add(struct timekeeper *tk, const struct timespec *ts) | |
115 | { | |
116 | tk->xtime_sec += ts->tv_sec; | |
117 | tk->xtime_nsec += ts->tv_nsec << tk->shift; | |
118 | } | |
8fcce546 | 119 | |
155ec602 MS |
120 | /** |
121 | * timekeeper_setup_internals - Set up internals to use clocksource clock. | |
122 | * | |
123 | * @clock: Pointer to clocksource. | |
124 | * | |
125 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment | |
126 | * pair and interval request. | |
127 | * | |
128 | * Unless you're the timekeeping code, you should not be using this! | |
129 | */ | |
130 | static void timekeeper_setup_internals(struct clocksource *clock) | |
131 | { | |
132 | cycle_t interval; | |
a386b5af | 133 | u64 tmp, ntpinterval; |
1e75fa8b | 134 | struct clocksource *old_clock; |
155ec602 | 135 | |
1e75fa8b | 136 | old_clock = timekeeper.clock; |
155ec602 MS |
137 | timekeeper.clock = clock; |
138 | clock->cycle_last = clock->read(clock); | |
139 | ||
140 | /* Do the ns -> cycle conversion first, using original mult */ | |
141 | tmp = NTP_INTERVAL_LENGTH; | |
142 | tmp <<= clock->shift; | |
a386b5af | 143 | ntpinterval = tmp; |
0a544198 MS |
144 | tmp += clock->mult/2; |
145 | do_div(tmp, clock->mult); | |
155ec602 MS |
146 | if (tmp == 0) |
147 | tmp = 1; | |
148 | ||
149 | interval = (cycle_t) tmp; | |
150 | timekeeper.cycle_interval = interval; | |
151 | ||
152 | /* Go back from cycles -> shifted ns */ | |
153 | timekeeper.xtime_interval = (u64) interval * clock->mult; | |
a386b5af | 154 | timekeeper.xtime_remainder = ntpinterval - timekeeper.xtime_interval; |
155ec602 | 155 | timekeeper.raw_interval = |
0a544198 | 156 | ((u64) interval * clock->mult) >> clock->shift; |
155ec602 | 157 | |
1e75fa8b JS |
158 | /* if changing clocks, convert xtime_nsec shift units */ |
159 | if (old_clock) { | |
160 | int shift_change = clock->shift - old_clock->shift; | |
161 | if (shift_change < 0) | |
162 | timekeeper.xtime_nsec >>= -shift_change; | |
163 | else | |
164 | timekeeper.xtime_nsec <<= shift_change; | |
165 | } | |
23ce7211 | 166 | timekeeper.shift = clock->shift; |
155ec602 MS |
167 | |
168 | timekeeper.ntp_error = 0; | |
23ce7211 | 169 | timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
0a544198 MS |
170 | |
171 | /* | |
172 | * The timekeeper keeps its own mult values for the currently | |
173 | * active clocksource. These value will be adjusted via NTP | |
174 | * to counteract clock drifting. | |
175 | */ | |
176 | timekeeper.mult = clock->mult; | |
155ec602 | 177 | } |
8524070b | 178 | |
2ba2a305 MS |
179 | /* Timekeeper helper functions. */ |
180 | static inline s64 timekeeping_get_ns(void) | |
181 | { | |
182 | cycle_t cycle_now, cycle_delta; | |
183 | struct clocksource *clock; | |
1e75fa8b | 184 | s64 nsec; |
2ba2a305 MS |
185 | |
186 | /* read clocksource: */ | |
187 | clock = timekeeper.clock; | |
188 | cycle_now = clock->read(clock); | |
189 | ||
190 | /* calculate the delta since the last update_wall_time: */ | |
191 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
192 | ||
1e75fa8b | 193 | nsec = cycle_delta * timekeeper.mult + timekeeper.xtime_nsec; |
f2a5a085 JS |
194 | nsec >>= timekeeper.shift; |
195 | ||
196 | /* If arch requires, add in gettimeoffset() */ | |
197 | return nsec + arch_gettimeoffset(); | |
2ba2a305 MS |
198 | } |
199 | ||
200 | static inline s64 timekeeping_get_ns_raw(void) | |
201 | { | |
202 | cycle_t cycle_now, cycle_delta; | |
203 | struct clocksource *clock; | |
f2a5a085 | 204 | s64 nsec; |
2ba2a305 MS |
205 | |
206 | /* read clocksource: */ | |
207 | clock = timekeeper.clock; | |
208 | cycle_now = clock->read(clock); | |
209 | ||
210 | /* calculate the delta since the last update_wall_time: */ | |
211 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
212 | ||
f2a5a085 JS |
213 | /* convert delta to nanoseconds. */ |
214 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); | |
215 | ||
216 | /* If arch requires, add in gettimeoffset() */ | |
217 | return nsec + arch_gettimeoffset(); | |
2ba2a305 MS |
218 | } |
219 | ||
5b9fe759 TG |
220 | static void update_rt_offset(void) |
221 | { | |
222 | struct timespec tmp, *wtm = &timekeeper.wall_to_monotonic; | |
223 | ||
224 | set_normalized_timespec(&tmp, -wtm->tv_sec, -wtm->tv_nsec); | |
225 | timekeeper.offs_real = timespec_to_ktime(tmp); | |
226 | } | |
227 | ||
cc06268c TG |
228 | /* must hold write on timekeeper.lock */ |
229 | static void timekeeping_update(bool clearntp) | |
230 | { | |
1e75fa8b JS |
231 | struct timespec xt; |
232 | ||
cc06268c TG |
233 | if (clearntp) { |
234 | timekeeper.ntp_error = 0; | |
235 | ntp_clear(); | |
236 | } | |
5b9fe759 | 237 | update_rt_offset(); |
1e75fa8b JS |
238 | xt = tk_xtime(&timekeeper); |
239 | update_vsyscall(&xt, &timekeeper.wall_to_monotonic, | |
cc06268c TG |
240 | timekeeper.clock, timekeeper.mult); |
241 | } | |
242 | ||
243 | ||
8524070b | 244 | /** |
155ec602 | 245 | * timekeeping_forward_now - update clock to the current time |
8524070b | 246 | * |
9a055117 RZ |
247 | * Forward the current clock to update its state since the last call to |
248 | * update_wall_time(). This is useful before significant clock changes, | |
249 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 250 | */ |
155ec602 | 251 | static void timekeeping_forward_now(void) |
8524070b JS |
252 | { |
253 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 254 | struct clocksource *clock; |
9a055117 | 255 | s64 nsec; |
8524070b | 256 | |
155ec602 | 257 | clock = timekeeper.clock; |
a0f7d48b | 258 | cycle_now = clock->read(clock); |
8524070b | 259 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 260 | clock->cycle_last = cycle_now; |
8524070b | 261 | |
1e75fa8b | 262 | timekeeper.xtime_nsec += cycle_delta * timekeeper.mult; |
7d27558c JS |
263 | |
264 | /* If arch requires, add in gettimeoffset() */ | |
1e75fa8b | 265 | timekeeper.xtime_nsec += arch_gettimeoffset() << timekeeper.shift; |
7d27558c | 266 | |
1e75fa8b | 267 | tk_normalize_xtime(&timekeeper); |
2d42244a | 268 | |
0a544198 | 269 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
01f71b47 | 270 | timespec_add_ns(&timekeeper.raw_time, nsec); |
8524070b JS |
271 | } |
272 | ||
273 | /** | |
efd9ac86 | 274 | * getnstimeofday - Returns the time of day in a timespec |
8524070b JS |
275 | * @ts: pointer to the timespec to be set |
276 | * | |
efd9ac86 | 277 | * Returns the time of day in a timespec. |
8524070b | 278 | */ |
efd9ac86 | 279 | void getnstimeofday(struct timespec *ts) |
8524070b JS |
280 | { |
281 | unsigned long seq; | |
1e75fa8b | 282 | s64 nsecs = 0; |
8524070b | 283 | |
1c5745aa TG |
284 | WARN_ON(timekeeping_suspended); |
285 | ||
8524070b | 286 | do { |
70471f2f | 287 | seq = read_seqbegin(&timekeeper.lock); |
8524070b | 288 | |
1e75fa8b JS |
289 | ts->tv_sec = timekeeper.xtime_sec; |
290 | ts->tv_nsec = timekeeping_get_ns(); | |
8524070b | 291 | |
70471f2f | 292 | } while (read_seqretry(&timekeeper.lock, seq)); |
8524070b JS |
293 | |
294 | timespec_add_ns(ts, nsecs); | |
295 | } | |
8524070b JS |
296 | EXPORT_SYMBOL(getnstimeofday); |
297 | ||
951ed4d3 MS |
298 | ktime_t ktime_get(void) |
299 | { | |
951ed4d3 MS |
300 | unsigned int seq; |
301 | s64 secs, nsecs; | |
302 | ||
303 | WARN_ON(timekeeping_suspended); | |
304 | ||
305 | do { | |
70471f2f | 306 | seq = read_seqbegin(&timekeeper.lock); |
1e75fa8b | 307 | secs = timekeeper.xtime_sec + |
8ff2cb92 | 308 | timekeeper.wall_to_monotonic.tv_sec; |
1e75fa8b | 309 | nsecs = timekeeping_get_ns() + |
8ff2cb92 | 310 | timekeeper.wall_to_monotonic.tv_nsec; |
951ed4d3 | 311 | |
70471f2f | 312 | } while (read_seqretry(&timekeeper.lock, seq)); |
951ed4d3 MS |
313 | /* |
314 | * Use ktime_set/ktime_add_ns to create a proper ktime on | |
315 | * 32-bit architectures without CONFIG_KTIME_SCALAR. | |
316 | */ | |
317 | return ktime_add_ns(ktime_set(secs, 0), nsecs); | |
318 | } | |
319 | EXPORT_SYMBOL_GPL(ktime_get); | |
320 | ||
321 | /** | |
322 | * ktime_get_ts - get the monotonic clock in timespec format | |
323 | * @ts: pointer to timespec variable | |
324 | * | |
325 | * The function calculates the monotonic clock from the realtime | |
326 | * clock and the wall_to_monotonic offset and stores the result | |
327 | * in normalized timespec format in the variable pointed to by @ts. | |
328 | */ | |
329 | void ktime_get_ts(struct timespec *ts) | |
330 | { | |
951ed4d3 MS |
331 | struct timespec tomono; |
332 | unsigned int seq; | |
951ed4d3 MS |
333 | |
334 | WARN_ON(timekeeping_suspended); | |
335 | ||
336 | do { | |
70471f2f | 337 | seq = read_seqbegin(&timekeeper.lock); |
1e75fa8b JS |
338 | ts->tv_sec = timekeeper.xtime_sec; |
339 | ts->tv_nsec = timekeeping_get_ns(); | |
d9f7217a | 340 | tomono = timekeeper.wall_to_monotonic; |
951ed4d3 | 341 | |
70471f2f | 342 | } while (read_seqretry(&timekeeper.lock, seq)); |
951ed4d3 MS |
343 | |
344 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
1e75fa8b | 345 | ts->tv_nsec + tomono.tv_nsec); |
951ed4d3 MS |
346 | } |
347 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
348 | ||
e2c18e49 AG |
349 | #ifdef CONFIG_NTP_PPS |
350 | ||
351 | /** | |
352 | * getnstime_raw_and_real - get day and raw monotonic time in timespec format | |
353 | * @ts_raw: pointer to the timespec to be set to raw monotonic time | |
354 | * @ts_real: pointer to the timespec to be set to the time of day | |
355 | * | |
356 | * This function reads both the time of day and raw monotonic time at the | |
357 | * same time atomically and stores the resulting timestamps in timespec | |
358 | * format. | |
359 | */ | |
360 | void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) | |
361 | { | |
362 | unsigned long seq; | |
363 | s64 nsecs_raw, nsecs_real; | |
364 | ||
365 | WARN_ON_ONCE(timekeeping_suspended); | |
366 | ||
367 | do { | |
70471f2f | 368 | seq = read_seqbegin(&timekeeper.lock); |
e2c18e49 | 369 | |
01f71b47 | 370 | *ts_raw = timekeeper.raw_time; |
1e75fa8b JS |
371 | ts_real->tv_sec = timekeeper.xtime_sec; |
372 | ts_real->tv_nsec = 0; | |
e2c18e49 AG |
373 | |
374 | nsecs_raw = timekeeping_get_ns_raw(); | |
375 | nsecs_real = timekeeping_get_ns(); | |
376 | ||
70471f2f | 377 | } while (read_seqretry(&timekeeper.lock, seq)); |
e2c18e49 AG |
378 | |
379 | timespec_add_ns(ts_raw, nsecs_raw); | |
380 | timespec_add_ns(ts_real, nsecs_real); | |
381 | } | |
382 | EXPORT_SYMBOL(getnstime_raw_and_real); | |
383 | ||
384 | #endif /* CONFIG_NTP_PPS */ | |
385 | ||
8524070b JS |
386 | /** |
387 | * do_gettimeofday - Returns the time of day in a timeval | |
388 | * @tv: pointer to the timeval to be set | |
389 | * | |
efd9ac86 | 390 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b JS |
391 | */ |
392 | void do_gettimeofday(struct timeval *tv) | |
393 | { | |
394 | struct timespec now; | |
395 | ||
efd9ac86 | 396 | getnstimeofday(&now); |
8524070b JS |
397 | tv->tv_sec = now.tv_sec; |
398 | tv->tv_usec = now.tv_nsec/1000; | |
399 | } | |
8524070b | 400 | EXPORT_SYMBOL(do_gettimeofday); |
d239f49d | 401 | |
8524070b JS |
402 | /** |
403 | * do_settimeofday - Sets the time of day | |
404 | * @tv: pointer to the timespec variable containing the new time | |
405 | * | |
406 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
407 | */ | |
1e6d7679 | 408 | int do_settimeofday(const struct timespec *tv) |
8524070b | 409 | { |
1e75fa8b | 410 | struct timespec ts_delta, xt; |
92c1d3ed | 411 | unsigned long flags; |
8524070b JS |
412 | |
413 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
414 | return -EINVAL; | |
415 | ||
92c1d3ed | 416 | write_seqlock_irqsave(&timekeeper.lock, flags); |
8524070b | 417 | |
155ec602 | 418 | timekeeping_forward_now(); |
9a055117 | 419 | |
1e75fa8b JS |
420 | xt = tk_xtime(&timekeeper); |
421 | ts_delta.tv_sec = tv->tv_sec - xt.tv_sec; | |
422 | ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec; | |
423 | ||
d9f7217a JS |
424 | timekeeper.wall_to_monotonic = |
425 | timespec_sub(timekeeper.wall_to_monotonic, ts_delta); | |
8524070b | 426 | |
1e75fa8b JS |
427 | tk_set_xtime(&timekeeper, tv); |
428 | ||
cc06268c | 429 | timekeeping_update(true); |
8524070b | 430 | |
92c1d3ed | 431 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
432 | |
433 | /* signal hrtimers about time change */ | |
434 | clock_was_set(); | |
435 | ||
436 | return 0; | |
437 | } | |
8524070b JS |
438 | EXPORT_SYMBOL(do_settimeofday); |
439 | ||
c528f7c6 JS |
440 | |
441 | /** | |
442 | * timekeeping_inject_offset - Adds or subtracts from the current time. | |
443 | * @tv: pointer to the timespec variable containing the offset | |
444 | * | |
445 | * Adds or subtracts an offset value from the current time. | |
446 | */ | |
447 | int timekeeping_inject_offset(struct timespec *ts) | |
448 | { | |
92c1d3ed | 449 | unsigned long flags; |
c528f7c6 JS |
450 | |
451 | if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) | |
452 | return -EINVAL; | |
453 | ||
92c1d3ed | 454 | write_seqlock_irqsave(&timekeeper.lock, flags); |
c528f7c6 JS |
455 | |
456 | timekeeping_forward_now(); | |
457 | ||
1e75fa8b JS |
458 | |
459 | tk_xtime_add(&timekeeper, ts); | |
d9f7217a JS |
460 | timekeeper.wall_to_monotonic = |
461 | timespec_sub(timekeeper.wall_to_monotonic, *ts); | |
c528f7c6 | 462 | |
cc06268c | 463 | timekeeping_update(true); |
c528f7c6 | 464 | |
92c1d3ed | 465 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
c528f7c6 JS |
466 | |
467 | /* signal hrtimers about time change */ | |
468 | clock_was_set(); | |
469 | ||
470 | return 0; | |
471 | } | |
472 | EXPORT_SYMBOL(timekeeping_inject_offset); | |
473 | ||
8524070b JS |
474 | /** |
475 | * change_clocksource - Swaps clocksources if a new one is available | |
476 | * | |
477 | * Accumulates current time interval and initializes new clocksource | |
478 | */ | |
75c5158f | 479 | static int change_clocksource(void *data) |
8524070b | 480 | { |
4614e6ad | 481 | struct clocksource *new, *old; |
f695cf94 | 482 | unsigned long flags; |
8524070b | 483 | |
75c5158f | 484 | new = (struct clocksource *) data; |
8524070b | 485 | |
f695cf94 JS |
486 | write_seqlock_irqsave(&timekeeper.lock, flags); |
487 | ||
155ec602 | 488 | timekeeping_forward_now(); |
75c5158f MS |
489 | if (!new->enable || new->enable(new) == 0) { |
490 | old = timekeeper.clock; | |
491 | timekeeper_setup_internals(new); | |
492 | if (old->disable) | |
493 | old->disable(old); | |
494 | } | |
f695cf94 JS |
495 | timekeeping_update(true); |
496 | ||
497 | write_sequnlock_irqrestore(&timekeeper.lock, flags); | |
498 | ||
75c5158f MS |
499 | return 0; |
500 | } | |
8524070b | 501 | |
75c5158f MS |
502 | /** |
503 | * timekeeping_notify - Install a new clock source | |
504 | * @clock: pointer to the clock source | |
505 | * | |
506 | * This function is called from clocksource.c after a new, better clock | |
507 | * source has been registered. The caller holds the clocksource_mutex. | |
508 | */ | |
509 | void timekeeping_notify(struct clocksource *clock) | |
510 | { | |
511 | if (timekeeper.clock == clock) | |
4614e6ad | 512 | return; |
75c5158f | 513 | stop_machine(change_clocksource, clock, NULL); |
8524070b | 514 | tick_clock_notify(); |
8524070b | 515 | } |
75c5158f | 516 | |
a40f262c TG |
517 | /** |
518 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
519 | * | |
520 | * returns the time in ktime_t format | |
521 | */ | |
522 | ktime_t ktime_get_real(void) | |
523 | { | |
524 | struct timespec now; | |
525 | ||
526 | getnstimeofday(&now); | |
527 | ||
528 | return timespec_to_ktime(now); | |
529 | } | |
530 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
8524070b | 531 | |
2d42244a JS |
532 | /** |
533 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
534 | * @ts: pointer to the timespec to be set | |
535 | * | |
536 | * Returns the raw monotonic time (completely un-modified by ntp) | |
537 | */ | |
538 | void getrawmonotonic(struct timespec *ts) | |
539 | { | |
540 | unsigned long seq; | |
541 | s64 nsecs; | |
2d42244a JS |
542 | |
543 | do { | |
70471f2f | 544 | seq = read_seqbegin(&timekeeper.lock); |
2ba2a305 | 545 | nsecs = timekeeping_get_ns_raw(); |
01f71b47 | 546 | *ts = timekeeper.raw_time; |
2d42244a | 547 | |
70471f2f | 548 | } while (read_seqretry(&timekeeper.lock, seq)); |
2d42244a JS |
549 | |
550 | timespec_add_ns(ts, nsecs); | |
551 | } | |
552 | EXPORT_SYMBOL(getrawmonotonic); | |
553 | ||
554 | ||
8524070b | 555 | /** |
cf4fc6cb | 556 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 557 | */ |
cf4fc6cb | 558 | int timekeeping_valid_for_hres(void) |
8524070b JS |
559 | { |
560 | unsigned long seq; | |
561 | int ret; | |
562 | ||
563 | do { | |
70471f2f | 564 | seq = read_seqbegin(&timekeeper.lock); |
8524070b | 565 | |
155ec602 | 566 | ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
8524070b | 567 | |
70471f2f | 568 | } while (read_seqretry(&timekeeper.lock, seq)); |
8524070b JS |
569 | |
570 | return ret; | |
571 | } | |
572 | ||
98962465 JH |
573 | /** |
574 | * timekeeping_max_deferment - Returns max time the clocksource can be deferred | |
98962465 JH |
575 | */ |
576 | u64 timekeeping_max_deferment(void) | |
577 | { | |
70471f2f JS |
578 | unsigned long seq; |
579 | u64 ret; | |
42e71e81 | 580 | |
70471f2f JS |
581 | do { |
582 | seq = read_seqbegin(&timekeeper.lock); | |
583 | ||
584 | ret = timekeeper.clock->max_idle_ns; | |
585 | ||
586 | } while (read_seqretry(&timekeeper.lock, seq)); | |
587 | ||
588 | return ret; | |
98962465 JH |
589 | } |
590 | ||
8524070b | 591 | /** |
d4f587c6 | 592 | * read_persistent_clock - Return time from the persistent clock. |
8524070b JS |
593 | * |
594 | * Weak dummy function for arches that do not yet support it. | |
d4f587c6 MS |
595 | * Reads the time from the battery backed persistent clock. |
596 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
8524070b JS |
597 | * |
598 | * XXX - Do be sure to remove it once all arches implement it. | |
599 | */ | |
d4f587c6 | 600 | void __attribute__((weak)) read_persistent_clock(struct timespec *ts) |
8524070b | 601 | { |
d4f587c6 MS |
602 | ts->tv_sec = 0; |
603 | ts->tv_nsec = 0; | |
8524070b JS |
604 | } |
605 | ||
23970e38 MS |
606 | /** |
607 | * read_boot_clock - Return time of the system start. | |
608 | * | |
609 | * Weak dummy function for arches that do not yet support it. | |
610 | * Function to read the exact time the system has been started. | |
611 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
612 | * | |
613 | * XXX - Do be sure to remove it once all arches implement it. | |
614 | */ | |
615 | void __attribute__((weak)) read_boot_clock(struct timespec *ts) | |
616 | { | |
617 | ts->tv_sec = 0; | |
618 | ts->tv_nsec = 0; | |
619 | } | |
620 | ||
8524070b JS |
621 | /* |
622 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
623 | */ | |
624 | void __init timekeeping_init(void) | |
625 | { | |
155ec602 | 626 | struct clocksource *clock; |
8524070b | 627 | unsigned long flags; |
23970e38 | 628 | struct timespec now, boot; |
d4f587c6 MS |
629 | |
630 | read_persistent_clock(&now); | |
23970e38 | 631 | read_boot_clock(&boot); |
8524070b | 632 | |
70471f2f | 633 | seqlock_init(&timekeeper.lock); |
8524070b | 634 | |
7dffa3c6 | 635 | ntp_init(); |
8524070b | 636 | |
70471f2f | 637 | write_seqlock_irqsave(&timekeeper.lock, flags); |
f1b82746 | 638 | clock = clocksource_default_clock(); |
a0f7d48b MS |
639 | if (clock->enable) |
640 | clock->enable(clock); | |
155ec602 | 641 | timekeeper_setup_internals(clock); |
8524070b | 642 | |
1e75fa8b | 643 | tk_set_xtime(&timekeeper, &now); |
01f71b47 JS |
644 | timekeeper.raw_time.tv_sec = 0; |
645 | timekeeper.raw_time.tv_nsec = 0; | |
1e75fa8b JS |
646 | if (boot.tv_sec == 0 && boot.tv_nsec == 0) |
647 | boot = tk_xtime(&timekeeper); | |
648 | ||
d9f7217a | 649 | set_normalized_timespec(&timekeeper.wall_to_monotonic, |
23970e38 | 650 | -boot.tv_sec, -boot.tv_nsec); |
5b9fe759 | 651 | update_rt_offset(); |
00c5fb77 JS |
652 | timekeeper.total_sleep_time.tv_sec = 0; |
653 | timekeeper.total_sleep_time.tv_nsec = 0; | |
70471f2f | 654 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
655 | } |
656 | ||
8524070b | 657 | /* time in seconds when suspend began */ |
d4f587c6 | 658 | static struct timespec timekeeping_suspend_time; |
8524070b | 659 | |
5b9fe759 TG |
660 | static void update_sleep_time(struct timespec t) |
661 | { | |
662 | timekeeper.total_sleep_time = t; | |
663 | timekeeper.offs_boot = timespec_to_ktime(t); | |
664 | } | |
665 | ||
304529b1 JS |
666 | /** |
667 | * __timekeeping_inject_sleeptime - Internal function to add sleep interval | |
668 | * @delta: pointer to a timespec delta value | |
669 | * | |
670 | * Takes a timespec offset measuring a suspend interval and properly | |
671 | * adds the sleep offset to the timekeeping variables. | |
672 | */ | |
673 | static void __timekeeping_inject_sleeptime(struct timespec *delta) | |
674 | { | |
cb5de2f8 | 675 | if (!timespec_valid(delta)) { |
cbaa5152 | 676 | printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid " |
cb5de2f8 JS |
677 | "sleep delta value!\n"); |
678 | return; | |
679 | } | |
680 | ||
1e75fa8b | 681 | tk_xtime_add(&timekeeper, delta); |
d9f7217a JS |
682 | timekeeper.wall_to_monotonic = |
683 | timespec_sub(timekeeper.wall_to_monotonic, *delta); | |
5b9fe759 | 684 | update_sleep_time(timespec_add(timekeeper.total_sleep_time, *delta)); |
304529b1 JS |
685 | } |
686 | ||
687 | ||
688 | /** | |
689 | * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values | |
690 | * @delta: pointer to a timespec delta value | |
691 | * | |
692 | * This hook is for architectures that cannot support read_persistent_clock | |
693 | * because their RTC/persistent clock is only accessible when irqs are enabled. | |
694 | * | |
695 | * This function should only be called by rtc_resume(), and allows | |
696 | * a suspend offset to be injected into the timekeeping values. | |
697 | */ | |
698 | void timekeeping_inject_sleeptime(struct timespec *delta) | |
699 | { | |
92c1d3ed | 700 | unsigned long flags; |
304529b1 JS |
701 | struct timespec ts; |
702 | ||
703 | /* Make sure we don't set the clock twice */ | |
704 | read_persistent_clock(&ts); | |
705 | if (!(ts.tv_sec == 0 && ts.tv_nsec == 0)) | |
706 | return; | |
707 | ||
92c1d3ed | 708 | write_seqlock_irqsave(&timekeeper.lock, flags); |
70471f2f | 709 | |
304529b1 JS |
710 | timekeeping_forward_now(); |
711 | ||
712 | __timekeeping_inject_sleeptime(delta); | |
713 | ||
cc06268c | 714 | timekeeping_update(true); |
304529b1 | 715 | |
92c1d3ed | 716 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
304529b1 JS |
717 | |
718 | /* signal hrtimers about time change */ | |
719 | clock_was_set(); | |
720 | } | |
721 | ||
722 | ||
8524070b JS |
723 | /** |
724 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
8524070b JS |
725 | * |
726 | * This is for the generic clocksource timekeeping. | |
727 | * xtime/wall_to_monotonic/jiffies/etc are | |
728 | * still managed by arch specific suspend/resume code. | |
729 | */ | |
e1a85b2c | 730 | static void timekeeping_resume(void) |
8524070b | 731 | { |
92c1d3ed | 732 | unsigned long flags; |
d4f587c6 MS |
733 | struct timespec ts; |
734 | ||
735 | read_persistent_clock(&ts); | |
8524070b | 736 | |
d10ff3fb TG |
737 | clocksource_resume(); |
738 | ||
92c1d3ed | 739 | write_seqlock_irqsave(&timekeeper.lock, flags); |
8524070b | 740 | |
d4f587c6 MS |
741 | if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { |
742 | ts = timespec_sub(ts, timekeeping_suspend_time); | |
304529b1 | 743 | __timekeeping_inject_sleeptime(&ts); |
8524070b JS |
744 | } |
745 | /* re-base the last cycle value */ | |
155ec602 MS |
746 | timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); |
747 | timekeeper.ntp_error = 0; | |
8524070b | 748 | timekeeping_suspended = 0; |
92c1d3ed | 749 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
750 | |
751 | touch_softlockup_watchdog(); | |
752 | ||
753 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); | |
754 | ||
755 | /* Resume hrtimers */ | |
b12a03ce | 756 | hrtimers_resume(); |
8524070b JS |
757 | } |
758 | ||
e1a85b2c | 759 | static int timekeeping_suspend(void) |
8524070b | 760 | { |
92c1d3ed | 761 | unsigned long flags; |
cb33217b JS |
762 | struct timespec delta, delta_delta; |
763 | static struct timespec old_delta; | |
8524070b | 764 | |
d4f587c6 | 765 | read_persistent_clock(&timekeeping_suspend_time); |
3be90950 | 766 | |
92c1d3ed | 767 | write_seqlock_irqsave(&timekeeper.lock, flags); |
155ec602 | 768 | timekeeping_forward_now(); |
8524070b | 769 | timekeeping_suspended = 1; |
cb33217b JS |
770 | |
771 | /* | |
772 | * To avoid drift caused by repeated suspend/resumes, | |
773 | * which each can add ~1 second drift error, | |
774 | * try to compensate so the difference in system time | |
775 | * and persistent_clock time stays close to constant. | |
776 | */ | |
1e75fa8b | 777 | delta = timespec_sub(tk_xtime(&timekeeper), timekeeping_suspend_time); |
cb33217b JS |
778 | delta_delta = timespec_sub(delta, old_delta); |
779 | if (abs(delta_delta.tv_sec) >= 2) { | |
780 | /* | |
781 | * if delta_delta is too large, assume time correction | |
782 | * has occured and set old_delta to the current delta. | |
783 | */ | |
784 | old_delta = delta; | |
785 | } else { | |
786 | /* Otherwise try to adjust old_system to compensate */ | |
787 | timekeeping_suspend_time = | |
788 | timespec_add(timekeeping_suspend_time, delta_delta); | |
789 | } | |
92c1d3ed | 790 | write_sequnlock_irqrestore(&timekeeper.lock, flags); |
8524070b JS |
791 | |
792 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
c54a42b1 | 793 | clocksource_suspend(); |
8524070b JS |
794 | |
795 | return 0; | |
796 | } | |
797 | ||
798 | /* sysfs resume/suspend bits for timekeeping */ | |
e1a85b2c | 799 | static struct syscore_ops timekeeping_syscore_ops = { |
8524070b JS |
800 | .resume = timekeeping_resume, |
801 | .suspend = timekeeping_suspend, | |
8524070b JS |
802 | }; |
803 | ||
e1a85b2c | 804 | static int __init timekeeping_init_ops(void) |
8524070b | 805 | { |
e1a85b2c RW |
806 | register_syscore_ops(&timekeeping_syscore_ops); |
807 | return 0; | |
8524070b JS |
808 | } |
809 | ||
e1a85b2c | 810 | device_initcall(timekeeping_init_ops); |
8524070b JS |
811 | |
812 | /* | |
813 | * If the error is already larger, we look ahead even further | |
814 | * to compensate for late or lost adjustments. | |
815 | */ | |
155ec602 | 816 | static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval, |
8524070b JS |
817 | s64 *offset) |
818 | { | |
819 | s64 tick_error, i; | |
820 | u32 look_ahead, adj; | |
821 | s32 error2, mult; | |
822 | ||
823 | /* | |
824 | * Use the current error value to determine how much to look ahead. | |
825 | * The larger the error the slower we adjust for it to avoid problems | |
826 | * with losing too many ticks, otherwise we would overadjust and | |
827 | * produce an even larger error. The smaller the adjustment the | |
828 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 829 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b JS |
830 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
831 | */ | |
155ec602 | 832 | error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b JS |
833 | error2 = abs(error2); |
834 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
835 | error2 >>= 2; | |
836 | ||
837 | /* | |
838 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
839 | * remove the single look ahead already included in the error. | |
840 | */ | |
ea7cf49a | 841 | tick_error = ntp_tick_length() >> (timekeeper.ntp_error_shift + 1); |
155ec602 | 842 | tick_error -= timekeeper.xtime_interval >> 1; |
8524070b JS |
843 | error = ((error - tick_error) >> look_ahead) + tick_error; |
844 | ||
845 | /* Finally calculate the adjustment shift value. */ | |
846 | i = *interval; | |
847 | mult = 1; | |
848 | if (error < 0) { | |
849 | error = -error; | |
850 | *interval = -*interval; | |
851 | *offset = -*offset; | |
852 | mult = -1; | |
853 | } | |
854 | for (adj = 0; error > i; adj++) | |
855 | error >>= 1; | |
856 | ||
857 | *interval <<= adj; | |
858 | *offset <<= adj; | |
859 | return mult << adj; | |
860 | } | |
861 | ||
862 | /* | |
863 | * Adjust the multiplier to reduce the error value, | |
864 | * this is optimized for the most common adjustments of -1,0,1, | |
865 | * for other values we can do a bit more work. | |
866 | */ | |
155ec602 | 867 | static void timekeeping_adjust(s64 offset) |
8524070b | 868 | { |
155ec602 | 869 | s64 error, interval = timekeeper.cycle_interval; |
8524070b JS |
870 | int adj; |
871 | ||
c2bc1111 | 872 | /* |
88b28adf | 873 | * The point of this is to check if the error is greater than half |
c2bc1111 JS |
874 | * an interval. |
875 | * | |
876 | * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs. | |
877 | * | |
878 | * Note we subtract one in the shift, so that error is really error*2. | |
3f86f28f JS |
879 | * This "saves" dividing(shifting) interval twice, but keeps the |
880 | * (error > interval) comparison as still measuring if error is | |
88b28adf | 881 | * larger than half an interval. |
c2bc1111 | 882 | * |
3f86f28f | 883 | * Note: It does not "save" on aggravation when reading the code. |
c2bc1111 | 884 | */ |
23ce7211 | 885 | error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1); |
8524070b | 886 | if (error > interval) { |
c2bc1111 JS |
887 | /* |
888 | * We now divide error by 4(via shift), which checks if | |
88b28adf | 889 | * the error is greater than twice the interval. |
c2bc1111 JS |
890 | * If it is greater, we need a bigadjust, if its smaller, |
891 | * we can adjust by 1. | |
892 | */ | |
8524070b | 893 | error >>= 2; |
c2bc1111 JS |
894 | /* |
895 | * XXX - In update_wall_time, we round up to the next | |
896 | * nanosecond, and store the amount rounded up into | |
897 | * the error. This causes the likely below to be unlikely. | |
898 | * | |
3f86f28f | 899 | * The proper fix is to avoid rounding up by using |
c2bc1111 JS |
900 | * the high precision timekeeper.xtime_nsec instead of |
901 | * xtime.tv_nsec everywhere. Fixing this will take some | |
902 | * time. | |
903 | */ | |
8524070b JS |
904 | if (likely(error <= interval)) |
905 | adj = 1; | |
906 | else | |
155ec602 | 907 | adj = timekeeping_bigadjust(error, &interval, &offset); |
8524070b | 908 | } else if (error < -interval) { |
c2bc1111 | 909 | /* See comment above, this is just switched for the negative */ |
8524070b JS |
910 | error >>= 2; |
911 | if (likely(error >= -interval)) { | |
912 | adj = -1; | |
913 | interval = -interval; | |
914 | offset = -offset; | |
915 | } else | |
155ec602 | 916 | adj = timekeeping_bigadjust(error, &interval, &offset); |
c2bc1111 | 917 | } else /* No adjustment needed */ |
8524070b JS |
918 | return; |
919 | ||
e919cfd4 JS |
920 | if (unlikely(timekeeper.clock->maxadj && |
921 | (timekeeper.mult + adj > | |
922 | timekeeper.clock->mult + timekeeper.clock->maxadj))) { | |
923 | printk_once(KERN_WARNING | |
924 | "Adjusting %s more than 11%% (%ld vs %ld)\n", | |
d65670a7 JS |
925 | timekeeper.clock->name, (long)timekeeper.mult + adj, |
926 | (long)timekeeper.clock->mult + | |
927 | timekeeper.clock->maxadj); | |
e919cfd4 | 928 | } |
c2bc1111 JS |
929 | /* |
930 | * So the following can be confusing. | |
931 | * | |
932 | * To keep things simple, lets assume adj == 1 for now. | |
933 | * | |
934 | * When adj != 1, remember that the interval and offset values | |
935 | * have been appropriately scaled so the math is the same. | |
936 | * | |
937 | * The basic idea here is that we're increasing the multiplier | |
938 | * by one, this causes the xtime_interval to be incremented by | |
939 | * one cycle_interval. This is because: | |
940 | * xtime_interval = cycle_interval * mult | |
941 | * So if mult is being incremented by one: | |
942 | * xtime_interval = cycle_interval * (mult + 1) | |
943 | * Its the same as: | |
944 | * xtime_interval = (cycle_interval * mult) + cycle_interval | |
945 | * Which can be shortened to: | |
946 | * xtime_interval += cycle_interval | |
947 | * | |
948 | * So offset stores the non-accumulated cycles. Thus the current | |
949 | * time (in shifted nanoseconds) is: | |
950 | * now = (offset * adj) + xtime_nsec | |
951 | * Now, even though we're adjusting the clock frequency, we have | |
952 | * to keep time consistent. In other words, we can't jump back | |
953 | * in time, and we also want to avoid jumping forward in time. | |
954 | * | |
955 | * So given the same offset value, we need the time to be the same | |
956 | * both before and after the freq adjustment. | |
957 | * now = (offset * adj_1) + xtime_nsec_1 | |
958 | * now = (offset * adj_2) + xtime_nsec_2 | |
959 | * So: | |
960 | * (offset * adj_1) + xtime_nsec_1 = | |
961 | * (offset * adj_2) + xtime_nsec_2 | |
962 | * And we know: | |
963 | * adj_2 = adj_1 + 1 | |
964 | * So: | |
965 | * (offset * adj_1) + xtime_nsec_1 = | |
966 | * (offset * (adj_1+1)) + xtime_nsec_2 | |
967 | * (offset * adj_1) + xtime_nsec_1 = | |
968 | * (offset * adj_1) + offset + xtime_nsec_2 | |
969 | * Canceling the sides: | |
970 | * xtime_nsec_1 = offset + xtime_nsec_2 | |
971 | * Which gives us: | |
972 | * xtime_nsec_2 = xtime_nsec_1 - offset | |
973 | * Which simplfies to: | |
974 | * xtime_nsec -= offset | |
975 | * | |
976 | * XXX - TODO: Doc ntp_error calculation. | |
977 | */ | |
0a544198 | 978 | timekeeper.mult += adj; |
155ec602 MS |
979 | timekeeper.xtime_interval += interval; |
980 | timekeeper.xtime_nsec -= offset; | |
981 | timekeeper.ntp_error -= (interval - offset) << | |
23ce7211 | 982 | timekeeper.ntp_error_shift; |
2a8c0883 JS |
983 | |
984 | /* | |
985 | * It may be possible that when we entered this function, xtime_nsec | |
986 | * was very small. Further, if we're slightly speeding the clocksource | |
987 | * in the code above, its possible the required corrective factor to | |
988 | * xtime_nsec could cause it to underflow. | |
989 | * | |
990 | * Now, since we already accumulated the second, cannot simply roll | |
991 | * the accumulated second back, since the NTP subsystem has been | |
992 | * notified via second_overflow. So instead we push xtime_nsec forward | |
993 | * by the amount we underflowed, and add that amount into the error. | |
994 | * | |
995 | * We'll correct this error next time through this function, when | |
996 | * xtime_nsec is not as small. | |
997 | */ | |
998 | if (unlikely((s64)timekeeper.xtime_nsec < 0)) { | |
999 | s64 neg = -(s64)timekeeper.xtime_nsec; | |
1000 | timekeeper.xtime_nsec = 0; | |
1001 | timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; | |
1002 | } | |
1003 | ||
8524070b JS |
1004 | } |
1005 | ||
83f57a11 | 1006 | |
1f4f9487 JS |
1007 | /** |
1008 | * accumulate_nsecs_to_secs - Accumulates nsecs into secs | |
1009 | * | |
1010 | * Helper function that accumulates a the nsecs greater then a second | |
1011 | * from the xtime_nsec field to the xtime_secs field. | |
1012 | * It also calls into the NTP code to handle leapsecond processing. | |
1013 | * | |
1014 | */ | |
1015 | static inline void accumulate_nsecs_to_secs(struct timekeeper *tk) | |
1016 | { | |
1017 | u64 nsecps = (u64)NSEC_PER_SEC << tk->shift; | |
1018 | ||
1019 | while (tk->xtime_nsec >= nsecps) { | |
1020 | int leap; | |
1021 | ||
1022 | tk->xtime_nsec -= nsecps; | |
1023 | tk->xtime_sec++; | |
1024 | ||
1025 | /* Figure out if its a leap sec and apply if needed */ | |
1026 | leap = second_overflow(tk->xtime_sec); | |
1027 | tk->xtime_sec += leap; | |
1028 | tk->wall_to_monotonic.tv_sec -= leap; | |
1029 | if (leap) | |
1030 | clock_was_set_delayed(); | |
1031 | ||
1032 | } | |
1033 | } | |
1034 | ||
1035 | ||
a092ff0f JS |
1036 | /** |
1037 | * logarithmic_accumulation - shifted accumulation of cycles | |
1038 | * | |
1039 | * This functions accumulates a shifted interval of cycles into | |
1040 | * into a shifted interval nanoseconds. Allows for O(log) accumulation | |
1041 | * loop. | |
1042 | * | |
1043 | * Returns the unconsumed cycles. | |
1044 | */ | |
fee84c43 | 1045 | static cycle_t logarithmic_accumulation(cycle_t offset, u32 shift) |
a092ff0f | 1046 | { |
deda2e81 | 1047 | u64 raw_nsecs; |
a092ff0f | 1048 | |
88b28adf | 1049 | /* If the offset is smaller than a shifted interval, do nothing */ |
a092ff0f JS |
1050 | if (offset < timekeeper.cycle_interval<<shift) |
1051 | return offset; | |
1052 | ||
1053 | /* Accumulate one shifted interval */ | |
1054 | offset -= timekeeper.cycle_interval << shift; | |
1055 | timekeeper.clock->cycle_last += timekeeper.cycle_interval << shift; | |
1056 | ||
1057 | timekeeper.xtime_nsec += timekeeper.xtime_interval << shift; | |
1f4f9487 JS |
1058 | |
1059 | accumulate_nsecs_to_secs(&timekeeper); | |
a092ff0f | 1060 | |
deda2e81 JW |
1061 | /* Accumulate raw time */ |
1062 | raw_nsecs = timekeeper.raw_interval << shift; | |
01f71b47 | 1063 | raw_nsecs += timekeeper.raw_time.tv_nsec; |
c7dcf87a JS |
1064 | if (raw_nsecs >= NSEC_PER_SEC) { |
1065 | u64 raw_secs = raw_nsecs; | |
1066 | raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); | |
01f71b47 | 1067 | timekeeper.raw_time.tv_sec += raw_secs; |
a092ff0f | 1068 | } |
01f71b47 | 1069 | timekeeper.raw_time.tv_nsec = raw_nsecs; |
a092ff0f JS |
1070 | |
1071 | /* Accumulate error between NTP and clock interval */ | |
ea7cf49a | 1072 | timekeeper.ntp_error += ntp_tick_length() << shift; |
a386b5af KP |
1073 | timekeeper.ntp_error -= |
1074 | (timekeeper.xtime_interval + timekeeper.xtime_remainder) << | |
a092ff0f JS |
1075 | (timekeeper.ntp_error_shift + shift); |
1076 | ||
1077 | return offset; | |
1078 | } | |
1079 | ||
83f57a11 | 1080 | |
8524070b JS |
1081 | /** |
1082 | * update_wall_time - Uses the current clocksource to increment the wall time | |
1083 | * | |
8524070b | 1084 | */ |
871cf1e5 | 1085 | static void update_wall_time(void) |
8524070b | 1086 | { |
155ec602 | 1087 | struct clocksource *clock; |
8524070b | 1088 | cycle_t offset; |
a092ff0f | 1089 | int shift = 0, maxshift; |
70471f2f | 1090 | unsigned long flags; |
1e75fa8b | 1091 | s64 remainder; |
70471f2f JS |
1092 | |
1093 | write_seqlock_irqsave(&timekeeper.lock, flags); | |
8524070b JS |
1094 | |
1095 | /* Make sure we're fully resumed: */ | |
1096 | if (unlikely(timekeeping_suspended)) | |
70471f2f | 1097 | goto out; |
8524070b | 1098 | |
155ec602 | 1099 | clock = timekeeper.clock; |
592913ec JS |
1100 | |
1101 | #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET | |
155ec602 | 1102 | offset = timekeeper.cycle_interval; |
592913ec JS |
1103 | #else |
1104 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; | |
8524070b | 1105 | #endif |
8524070b | 1106 | |
a092ff0f JS |
1107 | /* |
1108 | * With NO_HZ we may have to accumulate many cycle_intervals | |
1109 | * (think "ticks") worth of time at once. To do this efficiently, | |
1110 | * we calculate the largest doubling multiple of cycle_intervals | |
88b28adf | 1111 | * that is smaller than the offset. We then accumulate that |
a092ff0f JS |
1112 | * chunk in one go, and then try to consume the next smaller |
1113 | * doubled multiple. | |
8524070b | 1114 | */ |
a092ff0f JS |
1115 | shift = ilog2(offset) - ilog2(timekeeper.cycle_interval); |
1116 | shift = max(0, shift); | |
88b28adf | 1117 | /* Bound shift to one less than what overflows tick_length */ |
ea7cf49a | 1118 | maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; |
a092ff0f | 1119 | shift = min(shift, maxshift); |
155ec602 | 1120 | while (offset >= timekeeper.cycle_interval) { |
a092ff0f | 1121 | offset = logarithmic_accumulation(offset, shift); |
830ec045 JS |
1122 | if(offset < timekeeper.cycle_interval<<shift) |
1123 | shift--; | |
8524070b JS |
1124 | } |
1125 | ||
1126 | /* correct the clock when NTP error is too big */ | |
155ec602 | 1127 | timekeeping_adjust(offset); |
8524070b | 1128 | |
6c9bacb4 | 1129 | |
6a867a39 | 1130 | /* |
1e75fa8b JS |
1131 | * Store only full nanoseconds into xtime_nsec after rounding |
1132 | * it up and add the remainder to the error difference. | |
1133 | * XXX - This is necessary to avoid small 1ns inconsistnecies caused | |
1134 | * by truncating the remainder in vsyscalls. However, it causes | |
1135 | * additional work to be done in timekeeping_adjust(). Once | |
1136 | * the vsyscall implementations are converted to use xtime_nsec | |
1137 | * (shifted nanoseconds), this can be killed. | |
1138 | */ | |
1139 | remainder = timekeeper.xtime_nsec & ((1 << timekeeper.shift) - 1); | |
1140 | timekeeper.xtime_nsec -= remainder; | |
1141 | timekeeper.xtime_nsec += 1 << timekeeper.shift; | |
1142 | timekeeper.ntp_error += remainder << timekeeper.ntp_error_shift; | |
8524070b | 1143 | |
6a867a39 JS |
1144 | /* |
1145 | * Finally, make sure that after the rounding | |
1e75fa8b | 1146 | * xtime_nsec isn't larger than NSEC_PER_SEC |
6a867a39 | 1147 | */ |
1f4f9487 | 1148 | accumulate_nsecs_to_secs(&timekeeper); |
83f57a11 | 1149 | |
cc06268c | 1150 | timekeeping_update(false); |
70471f2f JS |
1151 | |
1152 | out: | |
1153 | write_sequnlock_irqrestore(&timekeeper.lock, flags); | |
1154 | ||
8524070b | 1155 | } |
7c3f1a57 TJ |
1156 | |
1157 | /** | |
1158 | * getboottime - Return the real time of system boot. | |
1159 | * @ts: pointer to the timespec to be set | |
1160 | * | |
abb3a4ea | 1161 | * Returns the wall-time of boot in a timespec. |
7c3f1a57 TJ |
1162 | * |
1163 | * This is based on the wall_to_monotonic offset and the total suspend | |
1164 | * time. Calls to settimeofday will affect the value returned (which | |
1165 | * basically means that however wrong your real time clock is at boot time, | |
1166 | * you get the right time here). | |
1167 | */ | |
1168 | void getboottime(struct timespec *ts) | |
1169 | { | |
36d47481 | 1170 | struct timespec boottime = { |
d9f7217a | 1171 | .tv_sec = timekeeper.wall_to_monotonic.tv_sec + |
00c5fb77 | 1172 | timekeeper.total_sleep_time.tv_sec, |
d9f7217a | 1173 | .tv_nsec = timekeeper.wall_to_monotonic.tv_nsec + |
00c5fb77 | 1174 | timekeeper.total_sleep_time.tv_nsec |
36d47481 | 1175 | }; |
d4f587c6 | 1176 | |
d4f587c6 | 1177 | set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); |
7c3f1a57 | 1178 | } |
c93d89f3 | 1179 | EXPORT_SYMBOL_GPL(getboottime); |
7c3f1a57 | 1180 | |
abb3a4ea JS |
1181 | |
1182 | /** | |
1183 | * get_monotonic_boottime - Returns monotonic time since boot | |
1184 | * @ts: pointer to the timespec to be set | |
1185 | * | |
1186 | * Returns the monotonic time since boot in a timespec. | |
1187 | * | |
1188 | * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also | |
1189 | * includes the time spent in suspend. | |
1190 | */ | |
1191 | void get_monotonic_boottime(struct timespec *ts) | |
1192 | { | |
1193 | struct timespec tomono, sleep; | |
1194 | unsigned int seq; | |
abb3a4ea JS |
1195 | |
1196 | WARN_ON(timekeeping_suspended); | |
1197 | ||
1198 | do { | |
70471f2f | 1199 | seq = read_seqbegin(&timekeeper.lock); |
1e75fa8b JS |
1200 | ts->tv_sec = timekeeper.xtime_sec; |
1201 | ts->tv_nsec = timekeeping_get_ns(); | |
d9f7217a | 1202 | tomono = timekeeper.wall_to_monotonic; |
00c5fb77 | 1203 | sleep = timekeeper.total_sleep_time; |
abb3a4ea | 1204 | |
70471f2f | 1205 | } while (read_seqretry(&timekeeper.lock, seq)); |
abb3a4ea JS |
1206 | |
1207 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec, | |
1e75fa8b | 1208 | ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec); |
abb3a4ea JS |
1209 | } |
1210 | EXPORT_SYMBOL_GPL(get_monotonic_boottime); | |
1211 | ||
1212 | /** | |
1213 | * ktime_get_boottime - Returns monotonic time since boot in a ktime | |
1214 | * | |
1215 | * Returns the monotonic time since boot in a ktime | |
1216 | * | |
1217 | * This is similar to CLOCK_MONTONIC/ktime_get, but also | |
1218 | * includes the time spent in suspend. | |
1219 | */ | |
1220 | ktime_t ktime_get_boottime(void) | |
1221 | { | |
1222 | struct timespec ts; | |
1223 | ||
1224 | get_monotonic_boottime(&ts); | |
1225 | return timespec_to_ktime(ts); | |
1226 | } | |
1227 | EXPORT_SYMBOL_GPL(ktime_get_boottime); | |
1228 | ||
7c3f1a57 TJ |
1229 | /** |
1230 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
1231 | * @ts: pointer to the timespec to be converted | |
1232 | */ | |
1233 | void monotonic_to_bootbased(struct timespec *ts) | |
1234 | { | |
00c5fb77 | 1235 | *ts = timespec_add(*ts, timekeeper.total_sleep_time); |
7c3f1a57 | 1236 | } |
c93d89f3 | 1237 | EXPORT_SYMBOL_GPL(monotonic_to_bootbased); |
2c6b47de | 1238 | |
17c38b74 JS |
1239 | unsigned long get_seconds(void) |
1240 | { | |
1e75fa8b | 1241 | return timekeeper.xtime_sec; |
17c38b74 JS |
1242 | } |
1243 | EXPORT_SYMBOL(get_seconds); | |
1244 | ||
da15cfda JS |
1245 | struct timespec __current_kernel_time(void) |
1246 | { | |
1e75fa8b | 1247 | return tk_xtime(&timekeeper); |
da15cfda | 1248 | } |
17c38b74 | 1249 | |
2c6b47de JS |
1250 | struct timespec current_kernel_time(void) |
1251 | { | |
1252 | struct timespec now; | |
1253 | unsigned long seq; | |
1254 | ||
1255 | do { | |
70471f2f | 1256 | seq = read_seqbegin(&timekeeper.lock); |
83f57a11 | 1257 | |
1e75fa8b | 1258 | now = tk_xtime(&timekeeper); |
70471f2f | 1259 | } while (read_seqretry(&timekeeper.lock, seq)); |
2c6b47de JS |
1260 | |
1261 | return now; | |
1262 | } | |
2c6b47de | 1263 | EXPORT_SYMBOL(current_kernel_time); |
da15cfda JS |
1264 | |
1265 | struct timespec get_monotonic_coarse(void) | |
1266 | { | |
1267 | struct timespec now, mono; | |
1268 | unsigned long seq; | |
1269 | ||
1270 | do { | |
70471f2f | 1271 | seq = read_seqbegin(&timekeeper.lock); |
83f57a11 | 1272 | |
1e75fa8b | 1273 | now = tk_xtime(&timekeeper); |
d9f7217a | 1274 | mono = timekeeper.wall_to_monotonic; |
70471f2f | 1275 | } while (read_seqretry(&timekeeper.lock, seq)); |
da15cfda JS |
1276 | |
1277 | set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, | |
1278 | now.tv_nsec + mono.tv_nsec); | |
1279 | return now; | |
1280 | } | |
871cf1e5 TH |
1281 | |
1282 | /* | |
1283 | * The 64-bit jiffies value is not atomic - you MUST NOT read it | |
1284 | * without sampling the sequence number in xtime_lock. | |
1285 | * jiffies is defined in the linker script... | |
1286 | */ | |
1287 | void do_timer(unsigned long ticks) | |
1288 | { | |
1289 | jiffies_64 += ticks; | |
1290 | update_wall_time(); | |
1291 | calc_global_load(ticks); | |
1292 | } | |
48cf76f7 TH |
1293 | |
1294 | /** | |
314ac371 JS |
1295 | * get_xtime_and_monotonic_and_sleep_offset() - get xtime, wall_to_monotonic, |
1296 | * and sleep offsets. | |
48cf76f7 TH |
1297 | * @xtim: pointer to timespec to be set with xtime |
1298 | * @wtom: pointer to timespec to be set with wall_to_monotonic | |
314ac371 | 1299 | * @sleep: pointer to timespec to be set with time in suspend |
48cf76f7 | 1300 | */ |
314ac371 JS |
1301 | void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, |
1302 | struct timespec *wtom, struct timespec *sleep) | |
48cf76f7 TH |
1303 | { |
1304 | unsigned long seq; | |
1305 | ||
1306 | do { | |
70471f2f | 1307 | seq = read_seqbegin(&timekeeper.lock); |
1e75fa8b | 1308 | *xtim = tk_xtime(&timekeeper); |
d9f7217a | 1309 | *wtom = timekeeper.wall_to_monotonic; |
00c5fb77 | 1310 | *sleep = timekeeper.total_sleep_time; |
70471f2f | 1311 | } while (read_seqretry(&timekeeper.lock, seq)); |
48cf76f7 | 1312 | } |
f0af911a | 1313 | |
f6c06abf TG |
1314 | #ifdef CONFIG_HIGH_RES_TIMERS |
1315 | /** | |
1316 | * ktime_get_update_offsets - hrtimer helper | |
1317 | * @offs_real: pointer to storage for monotonic -> realtime offset | |
1318 | * @offs_boot: pointer to storage for monotonic -> boottime offset | |
1319 | * | |
1320 | * Returns current monotonic time and updates the offsets | |
1321 | * Called from hrtimer_interupt() or retrigger_next_event() | |
1322 | */ | |
1323 | ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot) | |
1324 | { | |
1325 | ktime_t now; | |
1326 | unsigned int seq; | |
1327 | u64 secs, nsecs; | |
1328 | ||
1329 | do { | |
1330 | seq = read_seqbegin(&timekeeper.lock); | |
1331 | ||
1e75fa8b JS |
1332 | secs = timekeeper.xtime_sec; |
1333 | nsecs = timekeeping_get_ns(); | |
f6c06abf TG |
1334 | |
1335 | *offs_real = timekeeper.offs_real; | |
1336 | *offs_boot = timekeeper.offs_boot; | |
1337 | } while (read_seqretry(&timekeeper.lock, seq)); | |
1338 | ||
1339 | now = ktime_add_ns(ktime_set(secs, 0), nsecs); | |
1340 | now = ktime_sub(now, *offs_real); | |
1341 | return now; | |
1342 | } | |
1343 | #endif | |
1344 | ||
99ee5315 TG |
1345 | /** |
1346 | * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format | |
1347 | */ | |
1348 | ktime_t ktime_get_monotonic_offset(void) | |
1349 | { | |
1350 | unsigned long seq; | |
1351 | struct timespec wtom; | |
1352 | ||
1353 | do { | |
70471f2f | 1354 | seq = read_seqbegin(&timekeeper.lock); |
d9f7217a | 1355 | wtom = timekeeper.wall_to_monotonic; |
70471f2f JS |
1356 | } while (read_seqretry(&timekeeper.lock, seq)); |
1357 | ||
99ee5315 TG |
1358 | return timespec_to_ktime(wtom); |
1359 | } | |
a80b83b7 JS |
1360 | EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset); |
1361 | ||
99ee5315 | 1362 | |
f0af911a TH |
1363 | /** |
1364 | * xtime_update() - advances the timekeeping infrastructure | |
1365 | * @ticks: number of ticks, that have elapsed since the last call. | |
1366 | * | |
1367 | * Must be called with interrupts disabled. | |
1368 | */ | |
1369 | void xtime_update(unsigned long ticks) | |
1370 | { | |
1371 | write_seqlock(&xtime_lock); | |
1372 | do_timer(ticks); | |
1373 | write_sequnlock(&xtime_lock); | |
1374 | } |