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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; |
5b9fe759 | 68 | /* Offset clock monotonic -> clock realtime */ |
42e71e81 | 69 | ktime_t offs_real; |
6d0ef903 JS |
70 | /* time spent in suspend */ |
71 | struct timespec total_sleep_time; | |
5b9fe759 | 72 | /* Offset clock monotonic -> clock boottime */ |
42e71e81 | 73 | ktime_t offs_boot; |
6d0ef903 JS |
74 | /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */ |
75 | struct timespec raw_time; | |
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; | |
b44d50dc | 111 | tk->xtime_nsec = (u64)ts->tv_nsec << tk->shift; |
1e75fa8b JS |
112 | } |
113 | ||
114 | static void tk_xtime_add(struct timekeeper *tk, const struct timespec *ts) | |
115 | { | |
116 | tk->xtime_sec += ts->tv_sec; | |
b44d50dc | 117 | tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift; |
1e75fa8b | 118 | } |
8fcce546 | 119 | |
6d0ef903 JS |
120 | static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec wtm) |
121 | { | |
122 | struct timespec tmp; | |
123 | ||
124 | /* | |
125 | * Verify consistency of: offset_real = -wall_to_monotonic | |
126 | * before modifying anything | |
127 | */ | |
128 | set_normalized_timespec(&tmp, -tk->wall_to_monotonic.tv_sec, | |
129 | -tk->wall_to_monotonic.tv_nsec); | |
130 | WARN_ON_ONCE(tk->offs_real.tv64 != timespec_to_ktime(tmp).tv64); | |
131 | tk->wall_to_monotonic = wtm; | |
132 | set_normalized_timespec(&tmp, -wtm.tv_sec, -wtm.tv_nsec); | |
133 | tk->offs_real = timespec_to_ktime(tmp); | |
134 | } | |
135 | ||
136 | static void tk_set_sleep_time(struct timekeeper *tk, struct timespec t) | |
137 | { | |
138 | /* Verify consistency before modifying */ | |
139 | WARN_ON_ONCE(tk->offs_boot.tv64 != timespec_to_ktime(tk->total_sleep_time).tv64); | |
140 | ||
141 | tk->total_sleep_time = t; | |
142 | tk->offs_boot = timespec_to_ktime(t); | |
143 | } | |
144 | ||
155ec602 MS |
145 | /** |
146 | * timekeeper_setup_internals - Set up internals to use clocksource clock. | |
147 | * | |
148 | * @clock: Pointer to clocksource. | |
149 | * | |
150 | * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment | |
151 | * pair and interval request. | |
152 | * | |
153 | * Unless you're the timekeeping code, you should not be using this! | |
154 | */ | |
f726a697 | 155 | static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock) |
155ec602 MS |
156 | { |
157 | cycle_t interval; | |
a386b5af | 158 | u64 tmp, ntpinterval; |
1e75fa8b | 159 | struct clocksource *old_clock; |
155ec602 | 160 | |
f726a697 JS |
161 | old_clock = tk->clock; |
162 | tk->clock = clock; | |
155ec602 MS |
163 | clock->cycle_last = clock->read(clock); |
164 | ||
165 | /* Do the ns -> cycle conversion first, using original mult */ | |
166 | tmp = NTP_INTERVAL_LENGTH; | |
167 | tmp <<= clock->shift; | |
a386b5af | 168 | ntpinterval = tmp; |
0a544198 MS |
169 | tmp += clock->mult/2; |
170 | do_div(tmp, clock->mult); | |
155ec602 MS |
171 | if (tmp == 0) |
172 | tmp = 1; | |
173 | ||
174 | interval = (cycle_t) tmp; | |
f726a697 | 175 | tk->cycle_interval = interval; |
155ec602 MS |
176 | |
177 | /* Go back from cycles -> shifted ns */ | |
f726a697 JS |
178 | tk->xtime_interval = (u64) interval * clock->mult; |
179 | tk->xtime_remainder = ntpinterval - tk->xtime_interval; | |
180 | tk->raw_interval = | |
0a544198 | 181 | ((u64) interval * clock->mult) >> clock->shift; |
155ec602 | 182 | |
1e75fa8b JS |
183 | /* if changing clocks, convert xtime_nsec shift units */ |
184 | if (old_clock) { | |
185 | int shift_change = clock->shift - old_clock->shift; | |
186 | if (shift_change < 0) | |
f726a697 | 187 | tk->xtime_nsec >>= -shift_change; |
1e75fa8b | 188 | else |
f726a697 | 189 | tk->xtime_nsec <<= shift_change; |
1e75fa8b | 190 | } |
f726a697 | 191 | tk->shift = clock->shift; |
155ec602 | 192 | |
f726a697 JS |
193 | tk->ntp_error = 0; |
194 | tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; | |
0a544198 MS |
195 | |
196 | /* | |
197 | * The timekeeper keeps its own mult values for the currently | |
198 | * active clocksource. These value will be adjusted via NTP | |
199 | * to counteract clock drifting. | |
200 | */ | |
f726a697 | 201 | tk->mult = clock->mult; |
155ec602 | 202 | } |
8524070b | 203 | |
2ba2a305 | 204 | /* Timekeeper helper functions. */ |
f726a697 | 205 | static inline s64 timekeeping_get_ns(struct timekeeper *tk) |
2ba2a305 MS |
206 | { |
207 | cycle_t cycle_now, cycle_delta; | |
208 | struct clocksource *clock; | |
1e75fa8b | 209 | s64 nsec; |
2ba2a305 MS |
210 | |
211 | /* read clocksource: */ | |
f726a697 | 212 | clock = tk->clock; |
2ba2a305 MS |
213 | cycle_now = clock->read(clock); |
214 | ||
215 | /* calculate the delta since the last update_wall_time: */ | |
216 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
217 | ||
f726a697 JS |
218 | nsec = cycle_delta * tk->mult + tk->xtime_nsec; |
219 | nsec >>= tk->shift; | |
f2a5a085 JS |
220 | |
221 | /* If arch requires, add in gettimeoffset() */ | |
222 | return nsec + arch_gettimeoffset(); | |
2ba2a305 MS |
223 | } |
224 | ||
f726a697 | 225 | static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk) |
2ba2a305 MS |
226 | { |
227 | cycle_t cycle_now, cycle_delta; | |
228 | struct clocksource *clock; | |
f2a5a085 | 229 | s64 nsec; |
2ba2a305 MS |
230 | |
231 | /* read clocksource: */ | |
f726a697 | 232 | clock = tk->clock; |
2ba2a305 MS |
233 | cycle_now = clock->read(clock); |
234 | ||
235 | /* calculate the delta since the last update_wall_time: */ | |
236 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; | |
237 | ||
f2a5a085 JS |
238 | /* convert delta to nanoseconds. */ |
239 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); | |
240 | ||
241 | /* If arch requires, add in gettimeoffset() */ | |
242 | return nsec + arch_gettimeoffset(); | |
2ba2a305 MS |
243 | } |
244 | ||
cc06268c | 245 | /* must hold write on timekeeper.lock */ |
f726a697 | 246 | static void timekeeping_update(struct timekeeper *tk, bool clearntp) |
cc06268c | 247 | { |
1e75fa8b JS |
248 | struct timespec xt; |
249 | ||
cc06268c | 250 | if (clearntp) { |
f726a697 | 251 | tk->ntp_error = 0; |
cc06268c TG |
252 | ntp_clear(); |
253 | } | |
f726a697 JS |
254 | xt = tk_xtime(tk); |
255 | update_vsyscall(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult); | |
cc06268c TG |
256 | } |
257 | ||
8524070b | 258 | /** |
155ec602 | 259 | * timekeeping_forward_now - update clock to the current time |
8524070b | 260 | * |
9a055117 RZ |
261 | * Forward the current clock to update its state since the last call to |
262 | * update_wall_time(). This is useful before significant clock changes, | |
263 | * as it avoids having to deal with this time offset explicitly. | |
8524070b | 264 | */ |
f726a697 | 265 | static void timekeeping_forward_now(struct timekeeper *tk) |
8524070b JS |
266 | { |
267 | cycle_t cycle_now, cycle_delta; | |
155ec602 | 268 | struct clocksource *clock; |
9a055117 | 269 | s64 nsec; |
8524070b | 270 | |
f726a697 | 271 | clock = tk->clock; |
a0f7d48b | 272 | cycle_now = clock->read(clock); |
8524070b | 273 | cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
9a055117 | 274 | clock->cycle_last = cycle_now; |
8524070b | 275 | |
f726a697 | 276 | tk->xtime_nsec += cycle_delta * tk->mult; |
7d27558c JS |
277 | |
278 | /* If arch requires, add in gettimeoffset() */ | |
f726a697 | 279 | tk->xtime_nsec += arch_gettimeoffset() << tk->shift; |
7d27558c | 280 | |
f726a697 | 281 | tk_normalize_xtime(tk); |
2d42244a | 282 | |
0a544198 | 283 | nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
f726a697 | 284 | timespec_add_ns(&tk->raw_time, nsec); |
8524070b JS |
285 | } |
286 | ||
287 | /** | |
efd9ac86 | 288 | * getnstimeofday - Returns the time of day in a timespec |
8524070b JS |
289 | * @ts: pointer to the timespec to be set |
290 | * | |
efd9ac86 | 291 | * Returns the time of day in a timespec. |
8524070b | 292 | */ |
efd9ac86 | 293 | void getnstimeofday(struct timespec *ts) |
8524070b | 294 | { |
4e250fdd | 295 | struct timekeeper *tk = &timekeeper; |
8524070b | 296 | unsigned long seq; |
1e75fa8b | 297 | s64 nsecs = 0; |
8524070b | 298 | |
1c5745aa TG |
299 | WARN_ON(timekeeping_suspended); |
300 | ||
8524070b | 301 | do { |
4e250fdd | 302 | seq = read_seqbegin(&tk->lock); |
8524070b | 303 | |
4e250fdd JS |
304 | ts->tv_sec = tk->xtime_sec; |
305 | ts->tv_nsec = timekeeping_get_ns(tk); | |
8524070b | 306 | |
4e250fdd | 307 | } while (read_seqretry(&tk->lock, seq)); |
8524070b JS |
308 | |
309 | timespec_add_ns(ts, nsecs); | |
310 | } | |
8524070b JS |
311 | EXPORT_SYMBOL(getnstimeofday); |
312 | ||
951ed4d3 MS |
313 | ktime_t ktime_get(void) |
314 | { | |
4e250fdd | 315 | struct timekeeper *tk = &timekeeper; |
951ed4d3 MS |
316 | unsigned int seq; |
317 | s64 secs, nsecs; | |
318 | ||
319 | WARN_ON(timekeeping_suspended); | |
320 | ||
321 | do { | |
4e250fdd JS |
322 | seq = read_seqbegin(&tk->lock); |
323 | secs = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; | |
324 | nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec; | |
951ed4d3 | 325 | |
4e250fdd | 326 | } while (read_seqretry(&tk->lock, seq)); |
951ed4d3 MS |
327 | /* |
328 | * Use ktime_set/ktime_add_ns to create a proper ktime on | |
329 | * 32-bit architectures without CONFIG_KTIME_SCALAR. | |
330 | */ | |
331 | return ktime_add_ns(ktime_set(secs, 0), nsecs); | |
332 | } | |
333 | EXPORT_SYMBOL_GPL(ktime_get); | |
334 | ||
335 | /** | |
336 | * ktime_get_ts - get the monotonic clock in timespec format | |
337 | * @ts: pointer to timespec variable | |
338 | * | |
339 | * The function calculates the monotonic clock from the realtime | |
340 | * clock and the wall_to_monotonic offset and stores the result | |
341 | * in normalized timespec format in the variable pointed to by @ts. | |
342 | */ | |
343 | void ktime_get_ts(struct timespec *ts) | |
344 | { | |
4e250fdd | 345 | struct timekeeper *tk = &timekeeper; |
951ed4d3 MS |
346 | struct timespec tomono; |
347 | unsigned int seq; | |
951ed4d3 MS |
348 | |
349 | WARN_ON(timekeeping_suspended); | |
350 | ||
351 | do { | |
4e250fdd JS |
352 | seq = read_seqbegin(&tk->lock); |
353 | ts->tv_sec = tk->xtime_sec; | |
354 | ts->tv_nsec = timekeeping_get_ns(tk); | |
355 | tomono = tk->wall_to_monotonic; | |
951ed4d3 | 356 | |
4e250fdd | 357 | } while (read_seqretry(&tk->lock, seq)); |
951ed4d3 MS |
358 | |
359 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
1e75fa8b | 360 | ts->tv_nsec + tomono.tv_nsec); |
951ed4d3 MS |
361 | } |
362 | EXPORT_SYMBOL_GPL(ktime_get_ts); | |
363 | ||
e2c18e49 AG |
364 | #ifdef CONFIG_NTP_PPS |
365 | ||
366 | /** | |
367 | * getnstime_raw_and_real - get day and raw monotonic time in timespec format | |
368 | * @ts_raw: pointer to the timespec to be set to raw monotonic time | |
369 | * @ts_real: pointer to the timespec to be set to the time of day | |
370 | * | |
371 | * This function reads both the time of day and raw monotonic time at the | |
372 | * same time atomically and stores the resulting timestamps in timespec | |
373 | * format. | |
374 | */ | |
375 | void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) | |
376 | { | |
4e250fdd | 377 | struct timekeeper *tk = &timekeeper; |
e2c18e49 AG |
378 | unsigned long seq; |
379 | s64 nsecs_raw, nsecs_real; | |
380 | ||
381 | WARN_ON_ONCE(timekeeping_suspended); | |
382 | ||
383 | do { | |
4e250fdd | 384 | seq = read_seqbegin(&tk->lock); |
e2c18e49 | 385 | |
4e250fdd JS |
386 | *ts_raw = tk->raw_time; |
387 | ts_real->tv_sec = tk->xtime_sec; | |
1e75fa8b | 388 | ts_real->tv_nsec = 0; |
e2c18e49 | 389 | |
4e250fdd JS |
390 | nsecs_raw = timekeeping_get_ns_raw(tk); |
391 | nsecs_real = timekeeping_get_ns(tk); | |
e2c18e49 | 392 | |
4e250fdd | 393 | } while (read_seqretry(&tk->lock, seq)); |
e2c18e49 AG |
394 | |
395 | timespec_add_ns(ts_raw, nsecs_raw); | |
396 | timespec_add_ns(ts_real, nsecs_real); | |
397 | } | |
398 | EXPORT_SYMBOL(getnstime_raw_and_real); | |
399 | ||
400 | #endif /* CONFIG_NTP_PPS */ | |
401 | ||
8524070b JS |
402 | /** |
403 | * do_gettimeofday - Returns the time of day in a timeval | |
404 | * @tv: pointer to the timeval to be set | |
405 | * | |
efd9ac86 | 406 | * NOTE: Users should be converted to using getnstimeofday() |
8524070b JS |
407 | */ |
408 | void do_gettimeofday(struct timeval *tv) | |
409 | { | |
410 | struct timespec now; | |
411 | ||
efd9ac86 | 412 | getnstimeofday(&now); |
8524070b JS |
413 | tv->tv_sec = now.tv_sec; |
414 | tv->tv_usec = now.tv_nsec/1000; | |
415 | } | |
8524070b | 416 | EXPORT_SYMBOL(do_gettimeofday); |
d239f49d | 417 | |
8524070b JS |
418 | /** |
419 | * do_settimeofday - Sets the time of day | |
420 | * @tv: pointer to the timespec variable containing the new time | |
421 | * | |
422 | * Sets the time of day to the new time and update NTP and notify hrtimers | |
423 | */ | |
1e6d7679 | 424 | int do_settimeofday(const struct timespec *tv) |
8524070b | 425 | { |
4e250fdd | 426 | struct timekeeper *tk = &timekeeper; |
1e75fa8b | 427 | struct timespec ts_delta, xt; |
92c1d3ed | 428 | unsigned long flags; |
8524070b JS |
429 | |
430 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
431 | return -EINVAL; | |
432 | ||
4e250fdd | 433 | write_seqlock_irqsave(&tk->lock, flags); |
8524070b | 434 | |
4e250fdd | 435 | timekeeping_forward_now(tk); |
9a055117 | 436 | |
4e250fdd | 437 | xt = tk_xtime(tk); |
1e75fa8b JS |
438 | ts_delta.tv_sec = tv->tv_sec - xt.tv_sec; |
439 | ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec; | |
440 | ||
4e250fdd | 441 | tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, ts_delta)); |
8524070b | 442 | |
4e250fdd | 443 | tk_set_xtime(tk, tv); |
1e75fa8b | 444 | |
4e250fdd | 445 | timekeeping_update(tk, true); |
8524070b | 446 | |
4e250fdd | 447 | write_sequnlock_irqrestore(&tk->lock, flags); |
8524070b JS |
448 | |
449 | /* signal hrtimers about time change */ | |
450 | clock_was_set(); | |
451 | ||
452 | return 0; | |
453 | } | |
8524070b JS |
454 | EXPORT_SYMBOL(do_settimeofday); |
455 | ||
c528f7c6 JS |
456 | /** |
457 | * timekeeping_inject_offset - Adds or subtracts from the current time. | |
458 | * @tv: pointer to the timespec variable containing the offset | |
459 | * | |
460 | * Adds or subtracts an offset value from the current time. | |
461 | */ | |
462 | int timekeeping_inject_offset(struct timespec *ts) | |
463 | { | |
4e250fdd | 464 | struct timekeeper *tk = &timekeeper; |
92c1d3ed | 465 | unsigned long flags; |
c528f7c6 JS |
466 | |
467 | if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) | |
468 | return -EINVAL; | |
469 | ||
4e250fdd | 470 | write_seqlock_irqsave(&tk->lock, flags); |
c528f7c6 | 471 | |
4e250fdd | 472 | timekeeping_forward_now(tk); |
c528f7c6 | 473 | |
1e75fa8b | 474 | |
4e250fdd JS |
475 | tk_xtime_add(tk, ts); |
476 | tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *ts)); | |
c528f7c6 | 477 | |
4e250fdd | 478 | timekeeping_update(tk, true); |
c528f7c6 | 479 | |
4e250fdd | 480 | write_sequnlock_irqrestore(&tk->lock, flags); |
c528f7c6 JS |
481 | |
482 | /* signal hrtimers about time change */ | |
483 | clock_was_set(); | |
484 | ||
485 | return 0; | |
486 | } | |
487 | EXPORT_SYMBOL(timekeeping_inject_offset); | |
488 | ||
8524070b JS |
489 | /** |
490 | * change_clocksource - Swaps clocksources if a new one is available | |
491 | * | |
492 | * Accumulates current time interval and initializes new clocksource | |
493 | */ | |
75c5158f | 494 | static int change_clocksource(void *data) |
8524070b | 495 | { |
4e250fdd | 496 | struct timekeeper *tk = &timekeeper; |
4614e6ad | 497 | struct clocksource *new, *old; |
f695cf94 | 498 | unsigned long flags; |
8524070b | 499 | |
75c5158f | 500 | new = (struct clocksource *) data; |
8524070b | 501 | |
4e250fdd | 502 | write_seqlock_irqsave(&tk->lock, flags); |
f695cf94 | 503 | |
4e250fdd | 504 | timekeeping_forward_now(tk); |
75c5158f | 505 | if (!new->enable || new->enable(new) == 0) { |
4e250fdd JS |
506 | old = tk->clock; |
507 | tk_setup_internals(tk, new); | |
75c5158f MS |
508 | if (old->disable) |
509 | old->disable(old); | |
510 | } | |
4e250fdd | 511 | timekeeping_update(tk, true); |
f695cf94 | 512 | |
4e250fdd | 513 | write_sequnlock_irqrestore(&tk->lock, flags); |
f695cf94 | 514 | |
75c5158f MS |
515 | return 0; |
516 | } | |
8524070b | 517 | |
75c5158f MS |
518 | /** |
519 | * timekeeping_notify - Install a new clock source | |
520 | * @clock: pointer to the clock source | |
521 | * | |
522 | * This function is called from clocksource.c after a new, better clock | |
523 | * source has been registered. The caller holds the clocksource_mutex. | |
524 | */ | |
525 | void timekeeping_notify(struct clocksource *clock) | |
526 | { | |
4e250fdd JS |
527 | struct timekeeper *tk = &timekeeper; |
528 | ||
529 | if (tk->clock == clock) | |
4614e6ad | 530 | return; |
75c5158f | 531 | stop_machine(change_clocksource, clock, NULL); |
8524070b | 532 | tick_clock_notify(); |
8524070b | 533 | } |
75c5158f | 534 | |
a40f262c TG |
535 | /** |
536 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
537 | * | |
538 | * returns the time in ktime_t format | |
539 | */ | |
540 | ktime_t ktime_get_real(void) | |
541 | { | |
542 | struct timespec now; | |
543 | ||
544 | getnstimeofday(&now); | |
545 | ||
546 | return timespec_to_ktime(now); | |
547 | } | |
548 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
8524070b | 549 | |
2d42244a JS |
550 | /** |
551 | * getrawmonotonic - Returns the raw monotonic time in a timespec | |
552 | * @ts: pointer to the timespec to be set | |
553 | * | |
554 | * Returns the raw monotonic time (completely un-modified by ntp) | |
555 | */ | |
556 | void getrawmonotonic(struct timespec *ts) | |
557 | { | |
4e250fdd | 558 | struct timekeeper *tk = &timekeeper; |
2d42244a JS |
559 | unsigned long seq; |
560 | s64 nsecs; | |
2d42244a JS |
561 | |
562 | do { | |
4e250fdd JS |
563 | seq = read_seqbegin(&tk->lock); |
564 | nsecs = timekeeping_get_ns_raw(tk); | |
565 | *ts = tk->raw_time; | |
2d42244a | 566 | |
4e250fdd | 567 | } while (read_seqretry(&tk->lock, seq)); |
2d42244a JS |
568 | |
569 | timespec_add_ns(ts, nsecs); | |
570 | } | |
571 | EXPORT_SYMBOL(getrawmonotonic); | |
572 | ||
8524070b | 573 | /** |
cf4fc6cb | 574 | * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
8524070b | 575 | */ |
cf4fc6cb | 576 | int timekeeping_valid_for_hres(void) |
8524070b | 577 | { |
4e250fdd | 578 | struct timekeeper *tk = &timekeeper; |
8524070b JS |
579 | unsigned long seq; |
580 | int ret; | |
581 | ||
582 | do { | |
4e250fdd | 583 | seq = read_seqbegin(&tk->lock); |
8524070b | 584 | |
4e250fdd | 585 | ret = tk->clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
8524070b | 586 | |
4e250fdd | 587 | } while (read_seqretry(&tk->lock, seq)); |
8524070b JS |
588 | |
589 | return ret; | |
590 | } | |
591 | ||
98962465 JH |
592 | /** |
593 | * timekeeping_max_deferment - Returns max time the clocksource can be deferred | |
98962465 JH |
594 | */ |
595 | u64 timekeeping_max_deferment(void) | |
596 | { | |
4e250fdd | 597 | struct timekeeper *tk = &timekeeper; |
70471f2f JS |
598 | unsigned long seq; |
599 | u64 ret; | |
42e71e81 | 600 | |
70471f2f | 601 | do { |
4e250fdd | 602 | seq = read_seqbegin(&tk->lock); |
70471f2f | 603 | |
4e250fdd | 604 | ret = tk->clock->max_idle_ns; |
70471f2f | 605 | |
4e250fdd | 606 | } while (read_seqretry(&tk->lock, seq)); |
70471f2f JS |
607 | |
608 | return ret; | |
98962465 JH |
609 | } |
610 | ||
8524070b | 611 | /** |
d4f587c6 | 612 | * read_persistent_clock - Return time from the persistent clock. |
8524070b JS |
613 | * |
614 | * Weak dummy function for arches that do not yet support it. | |
d4f587c6 MS |
615 | * Reads the time from the battery backed persistent clock. |
616 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
8524070b JS |
617 | * |
618 | * XXX - Do be sure to remove it once all arches implement it. | |
619 | */ | |
d4f587c6 | 620 | void __attribute__((weak)) read_persistent_clock(struct timespec *ts) |
8524070b | 621 | { |
d4f587c6 MS |
622 | ts->tv_sec = 0; |
623 | ts->tv_nsec = 0; | |
8524070b JS |
624 | } |
625 | ||
23970e38 MS |
626 | /** |
627 | * read_boot_clock - Return time of the system start. | |
628 | * | |
629 | * Weak dummy function for arches that do not yet support it. | |
630 | * Function to read the exact time the system has been started. | |
631 | * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. | |
632 | * | |
633 | * XXX - Do be sure to remove it once all arches implement it. | |
634 | */ | |
635 | void __attribute__((weak)) read_boot_clock(struct timespec *ts) | |
636 | { | |
637 | ts->tv_sec = 0; | |
638 | ts->tv_nsec = 0; | |
639 | } | |
640 | ||
8524070b JS |
641 | /* |
642 | * timekeeping_init - Initializes the clocksource and common timekeeping values | |
643 | */ | |
644 | void __init timekeeping_init(void) | |
645 | { | |
4e250fdd | 646 | struct timekeeper *tk = &timekeeper; |
155ec602 | 647 | struct clocksource *clock; |
8524070b | 648 | unsigned long flags; |
6d0ef903 | 649 | struct timespec now, boot, tmp; |
d4f587c6 MS |
650 | |
651 | read_persistent_clock(&now); | |
23970e38 | 652 | read_boot_clock(&boot); |
8524070b | 653 | |
4e250fdd | 654 | seqlock_init(&tk->lock); |
8524070b | 655 | |
7dffa3c6 | 656 | ntp_init(); |
8524070b | 657 | |
4e250fdd | 658 | write_seqlock_irqsave(&tk->lock, flags); |
f1b82746 | 659 | clock = clocksource_default_clock(); |
a0f7d48b MS |
660 | if (clock->enable) |
661 | clock->enable(clock); | |
4e250fdd | 662 | tk_setup_internals(tk, clock); |
8524070b | 663 | |
4e250fdd JS |
664 | tk_set_xtime(tk, &now); |
665 | tk->raw_time.tv_sec = 0; | |
666 | tk->raw_time.tv_nsec = 0; | |
1e75fa8b | 667 | if (boot.tv_sec == 0 && boot.tv_nsec == 0) |
4e250fdd | 668 | boot = tk_xtime(tk); |
1e75fa8b | 669 | |
6d0ef903 | 670 | set_normalized_timespec(&tmp, -boot.tv_sec, -boot.tv_nsec); |
4e250fdd | 671 | tk_set_wall_to_mono(tk, tmp); |
6d0ef903 JS |
672 | |
673 | tmp.tv_sec = 0; | |
674 | tmp.tv_nsec = 0; | |
4e250fdd | 675 | tk_set_sleep_time(tk, tmp); |
6d0ef903 | 676 | |
4e250fdd | 677 | write_sequnlock_irqrestore(&tk->lock, flags); |
8524070b JS |
678 | } |
679 | ||
8524070b | 680 | /* time in seconds when suspend began */ |
d4f587c6 | 681 | static struct timespec timekeeping_suspend_time; |
8524070b | 682 | |
304529b1 JS |
683 | /** |
684 | * __timekeeping_inject_sleeptime - Internal function to add sleep interval | |
685 | * @delta: pointer to a timespec delta value | |
686 | * | |
687 | * Takes a timespec offset measuring a suspend interval and properly | |
688 | * adds the sleep offset to the timekeeping variables. | |
689 | */ | |
f726a697 JS |
690 | static void __timekeeping_inject_sleeptime(struct timekeeper *tk, |
691 | struct timespec *delta) | |
304529b1 | 692 | { |
cb5de2f8 | 693 | if (!timespec_valid(delta)) { |
cbaa5152 | 694 | printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid " |
cb5de2f8 JS |
695 | "sleep delta value!\n"); |
696 | return; | |
697 | } | |
f726a697 | 698 | tk_xtime_add(tk, delta); |
6d0ef903 JS |
699 | tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *delta)); |
700 | tk_set_sleep_time(tk, timespec_add(tk->total_sleep_time, *delta)); | |
304529b1 JS |
701 | } |
702 | ||
304529b1 JS |
703 | /** |
704 | * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values | |
705 | * @delta: pointer to a timespec delta value | |
706 | * | |
707 | * This hook is for architectures that cannot support read_persistent_clock | |
708 | * because their RTC/persistent clock is only accessible when irqs are enabled. | |
709 | * | |
710 | * This function should only be called by rtc_resume(), and allows | |
711 | * a suspend offset to be injected into the timekeeping values. | |
712 | */ | |
713 | void timekeeping_inject_sleeptime(struct timespec *delta) | |
714 | { | |
4e250fdd | 715 | struct timekeeper *tk = &timekeeper; |
92c1d3ed | 716 | unsigned long flags; |
304529b1 JS |
717 | struct timespec ts; |
718 | ||
719 | /* Make sure we don't set the clock twice */ | |
720 | read_persistent_clock(&ts); | |
721 | if (!(ts.tv_sec == 0 && ts.tv_nsec == 0)) | |
722 | return; | |
723 | ||
4e250fdd | 724 | write_seqlock_irqsave(&tk->lock, flags); |
70471f2f | 725 | |
4e250fdd | 726 | timekeeping_forward_now(tk); |
304529b1 | 727 | |
4e250fdd | 728 | __timekeeping_inject_sleeptime(tk, delta); |
304529b1 | 729 | |
4e250fdd | 730 | timekeeping_update(tk, true); |
304529b1 | 731 | |
4e250fdd | 732 | write_sequnlock_irqrestore(&tk->lock, flags); |
304529b1 JS |
733 | |
734 | /* signal hrtimers about time change */ | |
735 | clock_was_set(); | |
736 | } | |
737 | ||
8524070b JS |
738 | /** |
739 | * timekeeping_resume - Resumes the generic timekeeping subsystem. | |
8524070b JS |
740 | * |
741 | * This is for the generic clocksource timekeeping. | |
742 | * xtime/wall_to_monotonic/jiffies/etc are | |
743 | * still managed by arch specific suspend/resume code. | |
744 | */ | |
e1a85b2c | 745 | static void timekeeping_resume(void) |
8524070b | 746 | { |
4e250fdd | 747 | struct timekeeper *tk = &timekeeper; |
92c1d3ed | 748 | unsigned long flags; |
d4f587c6 MS |
749 | struct timespec ts; |
750 | ||
751 | read_persistent_clock(&ts); | |
8524070b | 752 | |
d10ff3fb TG |
753 | clocksource_resume(); |
754 | ||
4e250fdd | 755 | write_seqlock_irqsave(&tk->lock, flags); |
8524070b | 756 | |
d4f587c6 MS |
757 | if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { |
758 | ts = timespec_sub(ts, timekeeping_suspend_time); | |
4e250fdd | 759 | __timekeeping_inject_sleeptime(tk, &ts); |
8524070b JS |
760 | } |
761 | /* re-base the last cycle value */ | |
4e250fdd JS |
762 | tk->clock->cycle_last = tk->clock->read(tk->clock); |
763 | tk->ntp_error = 0; | |
8524070b | 764 | timekeeping_suspended = 0; |
4e250fdd JS |
765 | timekeeping_update(tk, false); |
766 | write_sequnlock_irqrestore(&tk->lock, flags); | |
8524070b JS |
767 | |
768 | touch_softlockup_watchdog(); | |
769 | ||
770 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); | |
771 | ||
772 | /* Resume hrtimers */ | |
b12a03ce | 773 | hrtimers_resume(); |
8524070b JS |
774 | } |
775 | ||
e1a85b2c | 776 | static int timekeeping_suspend(void) |
8524070b | 777 | { |
4e250fdd | 778 | struct timekeeper *tk = &timekeeper; |
92c1d3ed | 779 | unsigned long flags; |
cb33217b JS |
780 | struct timespec delta, delta_delta; |
781 | static struct timespec old_delta; | |
8524070b | 782 | |
d4f587c6 | 783 | read_persistent_clock(&timekeeping_suspend_time); |
3be90950 | 784 | |
4e250fdd JS |
785 | write_seqlock_irqsave(&tk->lock, flags); |
786 | timekeeping_forward_now(tk); | |
8524070b | 787 | timekeeping_suspended = 1; |
cb33217b JS |
788 | |
789 | /* | |
790 | * To avoid drift caused by repeated suspend/resumes, | |
791 | * which each can add ~1 second drift error, | |
792 | * try to compensate so the difference in system time | |
793 | * and persistent_clock time stays close to constant. | |
794 | */ | |
4e250fdd | 795 | delta = timespec_sub(tk_xtime(tk), timekeeping_suspend_time); |
cb33217b JS |
796 | delta_delta = timespec_sub(delta, old_delta); |
797 | if (abs(delta_delta.tv_sec) >= 2) { | |
798 | /* | |
799 | * if delta_delta is too large, assume time correction | |
800 | * has occured and set old_delta to the current delta. | |
801 | */ | |
802 | old_delta = delta; | |
803 | } else { | |
804 | /* Otherwise try to adjust old_system to compensate */ | |
805 | timekeeping_suspend_time = | |
806 | timespec_add(timekeeping_suspend_time, delta_delta); | |
807 | } | |
4e250fdd | 808 | write_sequnlock_irqrestore(&tk->lock, flags); |
8524070b JS |
809 | |
810 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); | |
c54a42b1 | 811 | clocksource_suspend(); |
8524070b JS |
812 | |
813 | return 0; | |
814 | } | |
815 | ||
816 | /* sysfs resume/suspend bits for timekeeping */ | |
e1a85b2c | 817 | static struct syscore_ops timekeeping_syscore_ops = { |
8524070b JS |
818 | .resume = timekeeping_resume, |
819 | .suspend = timekeeping_suspend, | |
8524070b JS |
820 | }; |
821 | ||
e1a85b2c | 822 | static int __init timekeeping_init_ops(void) |
8524070b | 823 | { |
e1a85b2c RW |
824 | register_syscore_ops(&timekeeping_syscore_ops); |
825 | return 0; | |
8524070b JS |
826 | } |
827 | ||
e1a85b2c | 828 | device_initcall(timekeeping_init_ops); |
8524070b JS |
829 | |
830 | /* | |
831 | * If the error is already larger, we look ahead even further | |
832 | * to compensate for late or lost adjustments. | |
833 | */ | |
f726a697 JS |
834 | static __always_inline int timekeeping_bigadjust(struct timekeeper *tk, |
835 | s64 error, s64 *interval, | |
8524070b JS |
836 | s64 *offset) |
837 | { | |
838 | s64 tick_error, i; | |
839 | u32 look_ahead, adj; | |
840 | s32 error2, mult; | |
841 | ||
842 | /* | |
843 | * Use the current error value to determine how much to look ahead. | |
844 | * The larger the error the slower we adjust for it to avoid problems | |
845 | * with losing too many ticks, otherwise we would overadjust and | |
846 | * produce an even larger error. The smaller the adjustment the | |
847 | * faster we try to adjust for it, as lost ticks can do less harm | |
3eb05676 | 848 | * here. This is tuned so that an error of about 1 msec is adjusted |
8524070b JS |
849 | * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). |
850 | */ | |
f726a697 | 851 | error2 = tk->ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); |
8524070b JS |
852 | error2 = abs(error2); |
853 | for (look_ahead = 0; error2 > 0; look_ahead++) | |
854 | error2 >>= 2; | |
855 | ||
856 | /* | |
857 | * Now calculate the error in (1 << look_ahead) ticks, but first | |
858 | * remove the single look ahead already included in the error. | |
859 | */ | |
f726a697 JS |
860 | tick_error = ntp_tick_length() >> (tk->ntp_error_shift + 1); |
861 | tick_error -= tk->xtime_interval >> 1; | |
8524070b JS |
862 | error = ((error - tick_error) >> look_ahead) + tick_error; |
863 | ||
864 | /* Finally calculate the adjustment shift value. */ | |
865 | i = *interval; | |
866 | mult = 1; | |
867 | if (error < 0) { | |
868 | error = -error; | |
869 | *interval = -*interval; | |
870 | *offset = -*offset; | |
871 | mult = -1; | |
872 | } | |
873 | for (adj = 0; error > i; adj++) | |
874 | error >>= 1; | |
875 | ||
876 | *interval <<= adj; | |
877 | *offset <<= adj; | |
878 | return mult << adj; | |
879 | } | |
880 | ||
881 | /* | |
882 | * Adjust the multiplier to reduce the error value, | |
883 | * this is optimized for the most common adjustments of -1,0,1, | |
884 | * for other values we can do a bit more work. | |
885 | */ | |
f726a697 | 886 | static void timekeeping_adjust(struct timekeeper *tk, s64 offset) |
8524070b | 887 | { |
f726a697 | 888 | s64 error, interval = tk->cycle_interval; |
8524070b JS |
889 | int adj; |
890 | ||
c2bc1111 | 891 | /* |
88b28adf | 892 | * The point of this is to check if the error is greater than half |
c2bc1111 JS |
893 | * an interval. |
894 | * | |
895 | * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs. | |
896 | * | |
897 | * Note we subtract one in the shift, so that error is really error*2. | |
3f86f28f JS |
898 | * This "saves" dividing(shifting) interval twice, but keeps the |
899 | * (error > interval) comparison as still measuring if error is | |
88b28adf | 900 | * larger than half an interval. |
c2bc1111 | 901 | * |
3f86f28f | 902 | * Note: It does not "save" on aggravation when reading the code. |
c2bc1111 | 903 | */ |
f726a697 | 904 | error = tk->ntp_error >> (tk->ntp_error_shift - 1); |
8524070b | 905 | if (error > interval) { |
c2bc1111 JS |
906 | /* |
907 | * We now divide error by 4(via shift), which checks if | |
88b28adf | 908 | * the error is greater than twice the interval. |
c2bc1111 JS |
909 | * If it is greater, we need a bigadjust, if its smaller, |
910 | * we can adjust by 1. | |
911 | */ | |
8524070b | 912 | error >>= 2; |
c2bc1111 JS |
913 | /* |
914 | * XXX - In update_wall_time, we round up to the next | |
915 | * nanosecond, and store the amount rounded up into | |
916 | * the error. This causes the likely below to be unlikely. | |
917 | * | |
3f86f28f | 918 | * The proper fix is to avoid rounding up by using |
4e250fdd | 919 | * the high precision tk->xtime_nsec instead of |
c2bc1111 JS |
920 | * xtime.tv_nsec everywhere. Fixing this will take some |
921 | * time. | |
922 | */ | |
8524070b JS |
923 | if (likely(error <= interval)) |
924 | adj = 1; | |
925 | else | |
f726a697 JS |
926 | adj = timekeeping_bigadjust(tk, error, &interval, |
927 | &offset); | |
8524070b | 928 | } else if (error < -interval) { |
c2bc1111 | 929 | /* See comment above, this is just switched for the negative */ |
8524070b JS |
930 | error >>= 2; |
931 | if (likely(error >= -interval)) { | |
932 | adj = -1; | |
933 | interval = -interval; | |
934 | offset = -offset; | |
935 | } else | |
f726a697 JS |
936 | adj = timekeeping_bigadjust(tk, error, &interval, |
937 | &offset); | |
938 | } else | |
8524070b JS |
939 | return; |
940 | ||
f726a697 JS |
941 | if (unlikely(tk->clock->maxadj && |
942 | (tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) { | |
e919cfd4 JS |
943 | printk_once(KERN_WARNING |
944 | "Adjusting %s more than 11%% (%ld vs %ld)\n", | |
f726a697 JS |
945 | tk->clock->name, (long)tk->mult + adj, |
946 | (long)tk->clock->mult + tk->clock->maxadj); | |
e919cfd4 | 947 | } |
c2bc1111 JS |
948 | /* |
949 | * So the following can be confusing. | |
950 | * | |
951 | * To keep things simple, lets assume adj == 1 for now. | |
952 | * | |
953 | * When adj != 1, remember that the interval and offset values | |
954 | * have been appropriately scaled so the math is the same. | |
955 | * | |
956 | * The basic idea here is that we're increasing the multiplier | |
957 | * by one, this causes the xtime_interval to be incremented by | |
958 | * one cycle_interval. This is because: | |
959 | * xtime_interval = cycle_interval * mult | |
960 | * So if mult is being incremented by one: | |
961 | * xtime_interval = cycle_interval * (mult + 1) | |
962 | * Its the same as: | |
963 | * xtime_interval = (cycle_interval * mult) + cycle_interval | |
964 | * Which can be shortened to: | |
965 | * xtime_interval += cycle_interval | |
966 | * | |
967 | * So offset stores the non-accumulated cycles. Thus the current | |
968 | * time (in shifted nanoseconds) is: | |
969 | * now = (offset * adj) + xtime_nsec | |
970 | * Now, even though we're adjusting the clock frequency, we have | |
971 | * to keep time consistent. In other words, we can't jump back | |
972 | * in time, and we also want to avoid jumping forward in time. | |
973 | * | |
974 | * So given the same offset value, we need the time to be the same | |
975 | * both before and after the freq adjustment. | |
976 | * now = (offset * adj_1) + xtime_nsec_1 | |
977 | * now = (offset * adj_2) + xtime_nsec_2 | |
978 | * So: | |
979 | * (offset * adj_1) + xtime_nsec_1 = | |
980 | * (offset * adj_2) + xtime_nsec_2 | |
981 | * And we know: | |
982 | * adj_2 = adj_1 + 1 | |
983 | * So: | |
984 | * (offset * adj_1) + xtime_nsec_1 = | |
985 | * (offset * (adj_1+1)) + xtime_nsec_2 | |
986 | * (offset * adj_1) + xtime_nsec_1 = | |
987 | * (offset * adj_1) + offset + xtime_nsec_2 | |
988 | * Canceling the sides: | |
989 | * xtime_nsec_1 = offset + xtime_nsec_2 | |
990 | * Which gives us: | |
991 | * xtime_nsec_2 = xtime_nsec_1 - offset | |
992 | * Which simplfies to: | |
993 | * xtime_nsec -= offset | |
994 | * | |
995 | * XXX - TODO: Doc ntp_error calculation. | |
996 | */ | |
f726a697 JS |
997 | tk->mult += adj; |
998 | tk->xtime_interval += interval; | |
999 | tk->xtime_nsec -= offset; | |
1000 | tk->ntp_error -= (interval - offset) << tk->ntp_error_shift; | |
2a8c0883 JS |
1001 | |
1002 | /* | |
1003 | * It may be possible that when we entered this function, xtime_nsec | |
1004 | * was very small. Further, if we're slightly speeding the clocksource | |
1005 | * in the code above, its possible the required corrective factor to | |
1006 | * xtime_nsec could cause it to underflow. | |
1007 | * | |
1008 | * Now, since we already accumulated the second, cannot simply roll | |
1009 | * the accumulated second back, since the NTP subsystem has been | |
1010 | * notified via second_overflow. So instead we push xtime_nsec forward | |
1011 | * by the amount we underflowed, and add that amount into the error. | |
1012 | * | |
1013 | * We'll correct this error next time through this function, when | |
1014 | * xtime_nsec is not as small. | |
1015 | */ | |
f726a697 JS |
1016 | if (unlikely((s64)tk->xtime_nsec < 0)) { |
1017 | s64 neg = -(s64)tk->xtime_nsec; | |
1018 | tk->xtime_nsec = 0; | |
1019 | tk->ntp_error += neg << tk->ntp_error_shift; | |
2a8c0883 JS |
1020 | } |
1021 | ||
8524070b JS |
1022 | } |
1023 | ||
1f4f9487 JS |
1024 | /** |
1025 | * accumulate_nsecs_to_secs - Accumulates nsecs into secs | |
1026 | * | |
1027 | * Helper function that accumulates a the nsecs greater then a second | |
1028 | * from the xtime_nsec field to the xtime_secs field. | |
1029 | * It also calls into the NTP code to handle leapsecond processing. | |
1030 | * | |
1031 | */ | |
1032 | static inline void accumulate_nsecs_to_secs(struct timekeeper *tk) | |
1033 | { | |
1034 | u64 nsecps = (u64)NSEC_PER_SEC << tk->shift; | |
1035 | ||
1036 | while (tk->xtime_nsec >= nsecps) { | |
1037 | int leap; | |
1038 | ||
1039 | tk->xtime_nsec -= nsecps; | |
1040 | tk->xtime_sec++; | |
1041 | ||
1042 | /* Figure out if its a leap sec and apply if needed */ | |
1043 | leap = second_overflow(tk->xtime_sec); | |
6d0ef903 JS |
1044 | if (unlikely(leap)) { |
1045 | struct timespec ts; | |
1046 | ||
1047 | tk->xtime_sec += leap; | |
1f4f9487 | 1048 | |
6d0ef903 JS |
1049 | ts.tv_sec = leap; |
1050 | ts.tv_nsec = 0; | |
1051 | tk_set_wall_to_mono(tk, | |
1052 | timespec_sub(tk->wall_to_monotonic, ts)); | |
1053 | ||
1054 | clock_was_set_delayed(); | |
1055 | } | |
1f4f9487 JS |
1056 | } |
1057 | } | |
1058 | ||
a092ff0f JS |
1059 | /** |
1060 | * logarithmic_accumulation - shifted accumulation of cycles | |
1061 | * | |
1062 | * This functions accumulates a shifted interval of cycles into | |
1063 | * into a shifted interval nanoseconds. Allows for O(log) accumulation | |
1064 | * loop. | |
1065 | * | |
1066 | * Returns the unconsumed cycles. | |
1067 | */ | |
f726a697 JS |
1068 | static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset, |
1069 | u32 shift) | |
a092ff0f | 1070 | { |
deda2e81 | 1071 | u64 raw_nsecs; |
a092ff0f | 1072 | |
f726a697 JS |
1073 | /* If the offset is smaller then a shifted interval, do nothing */ |
1074 | if (offset < tk->cycle_interval<<shift) | |
a092ff0f JS |
1075 | return offset; |
1076 | ||
1077 | /* Accumulate one shifted interval */ | |
f726a697 JS |
1078 | offset -= tk->cycle_interval << shift; |
1079 | tk->clock->cycle_last += tk->cycle_interval << shift; | |
a092ff0f | 1080 | |
f726a697 JS |
1081 | tk->xtime_nsec += tk->xtime_interval << shift; |
1082 | accumulate_nsecs_to_secs(tk); | |
a092ff0f | 1083 | |
deda2e81 | 1084 | /* Accumulate raw time */ |
f726a697 JS |
1085 | raw_nsecs = tk->raw_interval << shift; |
1086 | raw_nsecs += tk->raw_time.tv_nsec; | |
c7dcf87a JS |
1087 | if (raw_nsecs >= NSEC_PER_SEC) { |
1088 | u64 raw_secs = raw_nsecs; | |
1089 | raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); | |
f726a697 | 1090 | tk->raw_time.tv_sec += raw_secs; |
a092ff0f | 1091 | } |
f726a697 | 1092 | tk->raw_time.tv_nsec = raw_nsecs; |
a092ff0f JS |
1093 | |
1094 | /* Accumulate error between NTP and clock interval */ | |
f726a697 JS |
1095 | tk->ntp_error += ntp_tick_length() << shift; |
1096 | tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) << | |
1097 | (tk->ntp_error_shift + shift); | |
a092ff0f JS |
1098 | |
1099 | return offset; | |
1100 | } | |
1101 | ||
8524070b JS |
1102 | /** |
1103 | * update_wall_time - Uses the current clocksource to increment the wall time | |
1104 | * | |
8524070b | 1105 | */ |
871cf1e5 | 1106 | static void update_wall_time(void) |
8524070b | 1107 | { |
155ec602 | 1108 | struct clocksource *clock; |
4e250fdd | 1109 | struct timekeeper *tk = &timekeeper; |
8524070b | 1110 | cycle_t offset; |
a092ff0f | 1111 | int shift = 0, maxshift; |
70471f2f | 1112 | unsigned long flags; |
1e75fa8b | 1113 | s64 remainder; |
70471f2f | 1114 | |
4e250fdd | 1115 | write_seqlock_irqsave(&tk->lock, flags); |
8524070b JS |
1116 | |
1117 | /* Make sure we're fully resumed: */ | |
1118 | if (unlikely(timekeeping_suspended)) | |
70471f2f | 1119 | goto out; |
8524070b | 1120 | |
4e250fdd | 1121 | clock = tk->clock; |
592913ec JS |
1122 | |
1123 | #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET | |
4e250fdd | 1124 | offset = tk->cycle_interval; |
592913ec JS |
1125 | #else |
1126 | offset = (clock->read(clock) - clock->cycle_last) & clock->mask; | |
8524070b | 1127 | #endif |
8524070b | 1128 | |
a092ff0f JS |
1129 | /* |
1130 | * With NO_HZ we may have to accumulate many cycle_intervals | |
1131 | * (think "ticks") worth of time at once. To do this efficiently, | |
1132 | * we calculate the largest doubling multiple of cycle_intervals | |
88b28adf | 1133 | * that is smaller than the offset. We then accumulate that |
a092ff0f JS |
1134 | * chunk in one go, and then try to consume the next smaller |
1135 | * doubled multiple. | |
8524070b | 1136 | */ |
4e250fdd | 1137 | shift = ilog2(offset) - ilog2(tk->cycle_interval); |
a092ff0f | 1138 | shift = max(0, shift); |
88b28adf | 1139 | /* Bound shift to one less than what overflows tick_length */ |
ea7cf49a | 1140 | maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; |
a092ff0f | 1141 | shift = min(shift, maxshift); |
4e250fdd JS |
1142 | while (offset >= tk->cycle_interval) { |
1143 | offset = logarithmic_accumulation(tk, offset, shift); | |
1144 | if (offset < tk->cycle_interval<<shift) | |
830ec045 | 1145 | shift--; |
8524070b JS |
1146 | } |
1147 | ||
1148 | /* correct the clock when NTP error is too big */ | |
4e250fdd | 1149 | timekeeping_adjust(tk, offset); |
8524070b | 1150 | |
6c9bacb4 | 1151 | |
6a867a39 | 1152 | /* |
1e75fa8b JS |
1153 | * Store only full nanoseconds into xtime_nsec after rounding |
1154 | * it up and add the remainder to the error difference. | |
1155 | * XXX - This is necessary to avoid small 1ns inconsistnecies caused | |
1156 | * by truncating the remainder in vsyscalls. However, it causes | |
1157 | * additional work to be done in timekeeping_adjust(). Once | |
1158 | * the vsyscall implementations are converted to use xtime_nsec | |
1159 | * (shifted nanoseconds), this can be killed. | |
1160 | */ | |
4e250fdd JS |
1161 | remainder = tk->xtime_nsec & ((1 << tk->shift) - 1); |
1162 | tk->xtime_nsec -= remainder; | |
1163 | tk->xtime_nsec += 1 << tk->shift; | |
1164 | tk->ntp_error += remainder << tk->ntp_error_shift; | |
8524070b | 1165 | |
6a867a39 JS |
1166 | /* |
1167 | * Finally, make sure that after the rounding | |
1e75fa8b | 1168 | * xtime_nsec isn't larger than NSEC_PER_SEC |
6a867a39 | 1169 | */ |
4e250fdd | 1170 | accumulate_nsecs_to_secs(tk); |
83f57a11 | 1171 | |
4e250fdd | 1172 | timekeeping_update(tk, false); |
70471f2f JS |
1173 | |
1174 | out: | |
4e250fdd | 1175 | write_sequnlock_irqrestore(&tk->lock, flags); |
70471f2f | 1176 | |
8524070b | 1177 | } |
7c3f1a57 TJ |
1178 | |
1179 | /** | |
1180 | * getboottime - Return the real time of system boot. | |
1181 | * @ts: pointer to the timespec to be set | |
1182 | * | |
abb3a4ea | 1183 | * Returns the wall-time of boot in a timespec. |
7c3f1a57 TJ |
1184 | * |
1185 | * This is based on the wall_to_monotonic offset and the total suspend | |
1186 | * time. Calls to settimeofday will affect the value returned (which | |
1187 | * basically means that however wrong your real time clock is at boot time, | |
1188 | * you get the right time here). | |
1189 | */ | |
1190 | void getboottime(struct timespec *ts) | |
1191 | { | |
4e250fdd | 1192 | struct timekeeper *tk = &timekeeper; |
36d47481 | 1193 | struct timespec boottime = { |
4e250fdd JS |
1194 | .tv_sec = tk->wall_to_monotonic.tv_sec + |
1195 | tk->total_sleep_time.tv_sec, | |
1196 | .tv_nsec = tk->wall_to_monotonic.tv_nsec + | |
1197 | tk->total_sleep_time.tv_nsec | |
36d47481 | 1198 | }; |
d4f587c6 | 1199 | |
d4f587c6 | 1200 | set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); |
7c3f1a57 | 1201 | } |
c93d89f3 | 1202 | EXPORT_SYMBOL_GPL(getboottime); |
7c3f1a57 | 1203 | |
abb3a4ea JS |
1204 | /** |
1205 | * get_monotonic_boottime - Returns monotonic time since boot | |
1206 | * @ts: pointer to the timespec to be set | |
1207 | * | |
1208 | * Returns the monotonic time since boot in a timespec. | |
1209 | * | |
1210 | * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also | |
1211 | * includes the time spent in suspend. | |
1212 | */ | |
1213 | void get_monotonic_boottime(struct timespec *ts) | |
1214 | { | |
4e250fdd | 1215 | struct timekeeper *tk = &timekeeper; |
abb3a4ea JS |
1216 | struct timespec tomono, sleep; |
1217 | unsigned int seq; | |
abb3a4ea JS |
1218 | |
1219 | WARN_ON(timekeeping_suspended); | |
1220 | ||
1221 | do { | |
4e250fdd JS |
1222 | seq = read_seqbegin(&tk->lock); |
1223 | ts->tv_sec = tk->xtime_sec; | |
1224 | ts->tv_nsec = timekeeping_get_ns(tk); | |
1225 | tomono = tk->wall_to_monotonic; | |
1226 | sleep = tk->total_sleep_time; | |
abb3a4ea | 1227 | |
4e250fdd | 1228 | } while (read_seqretry(&tk->lock, seq)); |
abb3a4ea JS |
1229 | |
1230 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec, | |
1e75fa8b | 1231 | ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec); |
abb3a4ea JS |
1232 | } |
1233 | EXPORT_SYMBOL_GPL(get_monotonic_boottime); | |
1234 | ||
1235 | /** | |
1236 | * ktime_get_boottime - Returns monotonic time since boot in a ktime | |
1237 | * | |
1238 | * Returns the monotonic time since boot in a ktime | |
1239 | * | |
1240 | * This is similar to CLOCK_MONTONIC/ktime_get, but also | |
1241 | * includes the time spent in suspend. | |
1242 | */ | |
1243 | ktime_t ktime_get_boottime(void) | |
1244 | { | |
1245 | struct timespec ts; | |
1246 | ||
1247 | get_monotonic_boottime(&ts); | |
1248 | return timespec_to_ktime(ts); | |
1249 | } | |
1250 | EXPORT_SYMBOL_GPL(ktime_get_boottime); | |
1251 | ||
7c3f1a57 TJ |
1252 | /** |
1253 | * monotonic_to_bootbased - Convert the monotonic time to boot based. | |
1254 | * @ts: pointer to the timespec to be converted | |
1255 | */ | |
1256 | void monotonic_to_bootbased(struct timespec *ts) | |
1257 | { | |
4e250fdd JS |
1258 | struct timekeeper *tk = &timekeeper; |
1259 | ||
1260 | *ts = timespec_add(*ts, tk->total_sleep_time); | |
7c3f1a57 | 1261 | } |
c93d89f3 | 1262 | EXPORT_SYMBOL_GPL(monotonic_to_bootbased); |
2c6b47de | 1263 | |
17c38b74 JS |
1264 | unsigned long get_seconds(void) |
1265 | { | |
4e250fdd JS |
1266 | struct timekeeper *tk = &timekeeper; |
1267 | ||
1268 | return tk->xtime_sec; | |
17c38b74 JS |
1269 | } |
1270 | EXPORT_SYMBOL(get_seconds); | |
1271 | ||
da15cfda JS |
1272 | struct timespec __current_kernel_time(void) |
1273 | { | |
4e250fdd JS |
1274 | struct timekeeper *tk = &timekeeper; |
1275 | ||
1276 | return tk_xtime(tk); | |
da15cfda | 1277 | } |
17c38b74 | 1278 | |
2c6b47de JS |
1279 | struct timespec current_kernel_time(void) |
1280 | { | |
4e250fdd | 1281 | struct timekeeper *tk = &timekeeper; |
2c6b47de JS |
1282 | struct timespec now; |
1283 | unsigned long seq; | |
1284 | ||
1285 | do { | |
4e250fdd | 1286 | seq = read_seqbegin(&tk->lock); |
83f57a11 | 1287 | |
4e250fdd JS |
1288 | now = tk_xtime(tk); |
1289 | } while (read_seqretry(&tk->lock, seq)); | |
2c6b47de JS |
1290 | |
1291 | return now; | |
1292 | } | |
2c6b47de | 1293 | EXPORT_SYMBOL(current_kernel_time); |
da15cfda JS |
1294 | |
1295 | struct timespec get_monotonic_coarse(void) | |
1296 | { | |
4e250fdd | 1297 | struct timekeeper *tk = &timekeeper; |
da15cfda JS |
1298 | struct timespec now, mono; |
1299 | unsigned long seq; | |
1300 | ||
1301 | do { | |
4e250fdd | 1302 | seq = read_seqbegin(&tk->lock); |
83f57a11 | 1303 | |
4e250fdd JS |
1304 | now = tk_xtime(tk); |
1305 | mono = tk->wall_to_monotonic; | |
1306 | } while (read_seqretry(&tk->lock, seq)); | |
da15cfda JS |
1307 | |
1308 | set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, | |
1309 | now.tv_nsec + mono.tv_nsec); | |
1310 | return now; | |
1311 | } | |
871cf1e5 TH |
1312 | |
1313 | /* | |
1314 | * The 64-bit jiffies value is not atomic - you MUST NOT read it | |
1315 | * without sampling the sequence number in xtime_lock. | |
1316 | * jiffies is defined in the linker script... | |
1317 | */ | |
1318 | void do_timer(unsigned long ticks) | |
1319 | { | |
1320 | jiffies_64 += ticks; | |
1321 | update_wall_time(); | |
1322 | calc_global_load(ticks); | |
1323 | } | |
48cf76f7 TH |
1324 | |
1325 | /** | |
314ac371 JS |
1326 | * get_xtime_and_monotonic_and_sleep_offset() - get xtime, wall_to_monotonic, |
1327 | * and sleep offsets. | |
48cf76f7 TH |
1328 | * @xtim: pointer to timespec to be set with xtime |
1329 | * @wtom: pointer to timespec to be set with wall_to_monotonic | |
314ac371 | 1330 | * @sleep: pointer to timespec to be set with time in suspend |
48cf76f7 | 1331 | */ |
314ac371 JS |
1332 | void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, |
1333 | struct timespec *wtom, struct timespec *sleep) | |
48cf76f7 | 1334 | { |
4e250fdd | 1335 | struct timekeeper *tk = &timekeeper; |
48cf76f7 TH |
1336 | unsigned long seq; |
1337 | ||
1338 | do { | |
4e250fdd JS |
1339 | seq = read_seqbegin(&tk->lock); |
1340 | *xtim = tk_xtime(tk); | |
1341 | *wtom = tk->wall_to_monotonic; | |
1342 | *sleep = tk->total_sleep_time; | |
1343 | } while (read_seqretry(&tk->lock, seq)); | |
48cf76f7 | 1344 | } |
f0af911a | 1345 | |
f6c06abf TG |
1346 | #ifdef CONFIG_HIGH_RES_TIMERS |
1347 | /** | |
1348 | * ktime_get_update_offsets - hrtimer helper | |
1349 | * @offs_real: pointer to storage for monotonic -> realtime offset | |
1350 | * @offs_boot: pointer to storage for monotonic -> boottime offset | |
1351 | * | |
1352 | * Returns current monotonic time and updates the offsets | |
1353 | * Called from hrtimer_interupt() or retrigger_next_event() | |
1354 | */ | |
1355 | ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot) | |
1356 | { | |
4e250fdd | 1357 | struct timekeeper *tk = &timekeeper; |
f6c06abf TG |
1358 | ktime_t now; |
1359 | unsigned int seq; | |
1360 | u64 secs, nsecs; | |
1361 | ||
1362 | do { | |
4e250fdd | 1363 | seq = read_seqbegin(&tk->lock); |
f6c06abf | 1364 | |
4e250fdd JS |
1365 | secs = tk->xtime_sec; |
1366 | nsecs = timekeeping_get_ns(tk); | |
f6c06abf | 1367 | |
4e250fdd JS |
1368 | *offs_real = tk->offs_real; |
1369 | *offs_boot = tk->offs_boot; | |
1370 | } while (read_seqretry(&tk->lock, seq)); | |
f6c06abf TG |
1371 | |
1372 | now = ktime_add_ns(ktime_set(secs, 0), nsecs); | |
1373 | now = ktime_sub(now, *offs_real); | |
1374 | return now; | |
1375 | } | |
1376 | #endif | |
1377 | ||
99ee5315 TG |
1378 | /** |
1379 | * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format | |
1380 | */ | |
1381 | ktime_t ktime_get_monotonic_offset(void) | |
1382 | { | |
4e250fdd | 1383 | struct timekeeper *tk = &timekeeper; |
99ee5315 TG |
1384 | unsigned long seq; |
1385 | struct timespec wtom; | |
1386 | ||
1387 | do { | |
4e250fdd JS |
1388 | seq = read_seqbegin(&tk->lock); |
1389 | wtom = tk->wall_to_monotonic; | |
1390 | } while (read_seqretry(&tk->lock, seq)); | |
70471f2f | 1391 | |
99ee5315 TG |
1392 | return timespec_to_ktime(wtom); |
1393 | } | |
a80b83b7 JS |
1394 | EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset); |
1395 | ||
f0af911a TH |
1396 | /** |
1397 | * xtime_update() - advances the timekeeping infrastructure | |
1398 | * @ticks: number of ticks, that have elapsed since the last call. | |
1399 | * | |
1400 | * Must be called with interrupts disabled. | |
1401 | */ | |
1402 | void xtime_update(unsigned long ticks) | |
1403 | { | |
1404 | write_seqlock(&xtime_lock); | |
1405 | do_timer(ticks); | |
1406 | write_sequnlock(&xtime_lock); | |
1407 | } |