Branch data Line data Source code
1 : : // SPDX-License-Identifier: GPL-2.0
2 : : /*
3 : : * Kernel timekeeping code and accessor functions. Based on code from
4 : : * timer.c, moved in commit 8524070b7982.
5 : : */
6 : : #include <linux/timekeeper_internal.h>
7 : : #include <linux/module.h>
8 : : #include <linux/interrupt.h>
9 : : #include <linux/percpu.h>
10 : : #include <linux/init.h>
11 : : #include <linux/mm.h>
12 : : #include <linux/nmi.h>
13 : : #include <linux/sched.h>
14 : : #include <linux/sched/loadavg.h>
15 : : #include <linux/sched/clock.h>
16 : : #include <linux/syscore_ops.h>
17 : : #include <linux/clocksource.h>
18 : : #include <linux/jiffies.h>
19 : : #include <linux/time.h>
20 : : #include <linux/tick.h>
21 : : #include <linux/stop_machine.h>
22 : : #include <linux/pvclock_gtod.h>
23 : : #include <linux/compiler.h>
24 : : #include <linux/audit.h>
25 : :
26 : : #include "tick-internal.h"
27 : : #include "ntp_internal.h"
28 : : #include "timekeeping_internal.h"
29 : :
30 : : #define TK_CLEAR_NTP (1 << 0)
31 : : #define TK_MIRROR (1 << 1)
32 : : #define TK_CLOCK_WAS_SET (1 << 2)
33 : :
34 : : enum timekeeping_adv_mode {
35 : : /* Update timekeeper when a tick has passed */
36 : : TK_ADV_TICK,
37 : :
38 : : /* Update timekeeper on a direct frequency change */
39 : : TK_ADV_FREQ
40 : : };
41 : :
42 : : /*
43 : : * The most important data for readout fits into a single 64 byte
44 : : * cache line.
45 : : */
46 : : static struct {
47 : : seqcount_t seq;
48 : : struct timekeeper timekeeper;
49 : : } tk_core ____cacheline_aligned = {
50 : : .seq = SEQCNT_ZERO(tk_core.seq),
51 : : };
52 : :
53 : : static DEFINE_RAW_SPINLOCK(timekeeper_lock);
54 : : static struct timekeeper shadow_timekeeper;
55 : :
56 : : /**
57 : : * struct tk_fast - NMI safe timekeeper
58 : : * @seq: Sequence counter for protecting updates. The lowest bit
59 : : * is the index for the tk_read_base array
60 : : * @base: tk_read_base array. Access is indexed by the lowest bit of
61 : : * @seq.
62 : : *
63 : : * See @update_fast_timekeeper() below.
64 : : */
65 : : struct tk_fast {
66 : : seqcount_t seq;
67 : : struct tk_read_base base[2];
68 : : };
69 : :
70 : : /* Suspend-time cycles value for halted fast timekeeper. */
71 : : static u64 cycles_at_suspend;
72 : :
73 : 0 : static u64 dummy_clock_read(struct clocksource *cs)
74 : : {
75 : 0 : return cycles_at_suspend;
76 : : }
77 : :
78 : : static struct clocksource dummy_clock = {
79 : : .read = dummy_clock_read,
80 : : };
81 : :
82 : : static struct tk_fast tk_fast_mono ____cacheline_aligned = {
83 : : .base[0] = { .clock = &dummy_clock, },
84 : : .base[1] = { .clock = &dummy_clock, },
85 : : };
86 : :
87 : : static struct tk_fast tk_fast_raw ____cacheline_aligned = {
88 : : .base[0] = { .clock = &dummy_clock, },
89 : : .base[1] = { .clock = &dummy_clock, },
90 : : };
91 : :
92 : : /* flag for if timekeeping is suspended */
93 : : int __read_mostly timekeeping_suspended;
94 : :
95 : 2026 : static inline void tk_normalize_xtime(struct timekeeper *tk)
96 : : {
97 [ + + ]: 4250 : while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
98 : 198 : tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
99 : 198 : tk->xtime_sec++;
100 : : }
101 [ + + ]: 2034 : while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
102 : 8 : tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
103 : 8 : tk->raw_sec++;
104 : : }
105 : 2026 : }
106 : :
107 : : static inline struct timespec64 tk_xtime(const struct timekeeper *tk)
108 : : {
109 : : struct timespec64 ts;
110 : :
111 : 21850566 : ts.tv_sec = tk->xtime_sec;
112 : 21850566 : ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
113 : : return ts;
114 : : }
115 : :
116 : : static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
117 : : {
118 : 1218 : tk->xtime_sec = ts->tv_sec;
119 : 1218 : tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
120 : : }
121 : :
122 : 404 : static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
123 : : {
124 : 404 : tk->xtime_sec += ts->tv_sec;
125 : 404 : tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
126 : 404 : tk_normalize_xtime(tk);
127 : 404 : }
128 : :
129 : 1622 : static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
130 : : {
131 : : struct timespec64 tmp;
132 : :
133 : : /*
134 : : * Verify consistency of: offset_real = -wall_to_monotonic
135 : : * before modifying anything
136 : : */
137 : 3244 : set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
138 : 1622 : -tk->wall_to_monotonic.tv_nsec);
139 [ - + # # ]: 3244 : WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
140 : 1622 : tk->wall_to_monotonic = wtm;
141 : 1622 : set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
142 : 1622 : tk->offs_real = timespec64_to_ktime(tmp);
143 : 3244 : tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
144 : 1622 : }
145 : :
146 : 0 : static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
147 : : {
148 : 0 : tk->offs_boot = ktime_add(tk->offs_boot, delta);
149 : : /*
150 : : * Timespec representation for VDSO update to avoid 64bit division
151 : : * on every update.
152 : : */
153 : 0 : tk->monotonic_to_boot = ktime_to_timespec64(tk->offs_boot);
154 : 0 : }
155 : :
156 : : /*
157 : : * tk_clock_read - atomic clocksource read() helper
158 : : *
159 : : * This helper is necessary to use in the read paths because, while the
160 : : * seqlock ensures we don't return a bad value while structures are updated,
161 : : * it doesn't protect from potential crashes. There is the possibility that
162 : : * the tkr's clocksource may change between the read reference, and the
163 : : * clock reference passed to the read function. This can cause crashes if
164 : : * the wrong clocksource is passed to the wrong read function.
165 : : * This isn't necessary to use when holding the timekeeper_lock or doing
166 : : * a read of the fast-timekeeper tkrs (which is protected by its own locking
167 : : * and update logic).
168 : : */
169 : 6133866 : static inline u64 tk_clock_read(const struct tk_read_base *tkr)
170 : : {
171 : 502601026 : struct clocksource *clock = READ_ONCE(tkr->clock);
172 : :
173 : 502601026 : return clock->read(clock);
174 : : }
175 : :
176 : : #ifdef CONFIG_DEBUG_TIMEKEEPING
177 : : #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
178 : :
179 : : static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
180 : : {
181 : :
182 : : u64 max_cycles = tk->tkr_mono.clock->max_cycles;
183 : : const char *name = tk->tkr_mono.clock->name;
184 : :
185 : : if (offset > max_cycles) {
186 : : printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
187 : : offset, name, max_cycles);
188 : : printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
189 : : } else {
190 : : if (offset > (max_cycles >> 1)) {
191 : : printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
192 : : offset, name, max_cycles >> 1);
193 : : printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
194 : : }
195 : : }
196 : :
197 : : if (tk->underflow_seen) {
198 : : if (jiffies - tk->last_warning > WARNING_FREQ) {
199 : : printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
200 : : printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
201 : : printk_deferred(" Your kernel is probably still fine.\n");
202 : : tk->last_warning = jiffies;
203 : : }
204 : : tk->underflow_seen = 0;
205 : : }
206 : :
207 : : if (tk->overflow_seen) {
208 : : if (jiffies - tk->last_warning > WARNING_FREQ) {
209 : : printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
210 : : printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
211 : : printk_deferred(" Your kernel is probably still fine.\n");
212 : : tk->last_warning = jiffies;
213 : : }
214 : : tk->overflow_seen = 0;
215 : : }
216 : : }
217 : :
218 : : static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
219 : : {
220 : : struct timekeeper *tk = &tk_core.timekeeper;
221 : : u64 now, last, mask, max, delta;
222 : : unsigned int seq;
223 : :
224 : : /*
225 : : * Since we're called holding a seqlock, the data may shift
226 : : * under us while we're doing the calculation. This can cause
227 : : * false positives, since we'd note a problem but throw the
228 : : * results away. So nest another seqlock here to atomically
229 : : * grab the points we are checking with.
230 : : */
231 : : do {
232 : : seq = read_seqcount_begin(&tk_core.seq);
233 : : now = tk_clock_read(tkr);
234 : : last = tkr->cycle_last;
235 : : mask = tkr->mask;
236 : : max = tkr->clock->max_cycles;
237 : : } while (read_seqcount_retry(&tk_core.seq, seq));
238 : :
239 : : delta = clocksource_delta(now, last, mask);
240 : :
241 : : /*
242 : : * Try to catch underflows by checking if we are seeing small
243 : : * mask-relative negative values.
244 : : */
245 : : if (unlikely((~delta & mask) < (mask >> 3))) {
246 : : tk->underflow_seen = 1;
247 : : delta = 0;
248 : : }
249 : :
250 : : /* Cap delta value to the max_cycles values to avoid mult overflows */
251 : : if (unlikely(delta > max)) {
252 : : tk->overflow_seen = 1;
253 : : delta = tkr->clock->max_cycles;
254 : : }
255 : :
256 : : return delta;
257 : : }
258 : : #else
259 : : static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
260 : : {
261 : : }
262 : : static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
263 : : {
264 : : u64 cycle_now, delta;
265 : :
266 : : /* read clocksource */
267 : : cycle_now = tk_clock_read(tkr);
268 : :
269 : : /* calculate the delta since the last update_wall_time */
270 : 492271124 : delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
271 : :
272 : : return delta;
273 : : }
274 : : #endif
275 : :
276 : : /**
277 : : * tk_setup_internals - Set up internals to use clocksource clock.
278 : : *
279 : : * @tk: The target timekeeper to setup.
280 : : * @clock: Pointer to clocksource.
281 : : *
282 : : * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
283 : : * pair and interval request.
284 : : *
285 : : * Unless you're the timekeeping code, you should not be using this!
286 : : */
287 : 808 : static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
288 : : {
289 : : u64 interval;
290 : : u64 tmp, ntpinterval;
291 : : struct clocksource *old_clock;
292 : :
293 : 808 : ++tk->cs_was_changed_seq;
294 : 808 : old_clock = tk->tkr_mono.clock;
295 : 808 : tk->tkr_mono.clock = clock;
296 : 808 : tk->tkr_mono.mask = clock->mask;
297 : 808 : tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
298 : :
299 : 808 : tk->tkr_raw.clock = clock;
300 : 808 : tk->tkr_raw.mask = clock->mask;
301 : 808 : tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
302 : :
303 : : /* Do the ns -> cycle conversion first, using original mult */
304 : 808 : tmp = NTP_INTERVAL_LENGTH;
305 : 808 : tmp <<= clock->shift;
306 : : ntpinterval = tmp;
307 : 808 : tmp += clock->mult/2;
308 [ - + # # : 808 : do_div(tmp, clock->mult);
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # - +
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
+ + ]
309 [ - + ]: 808 : if (tmp == 0)
310 : 0 : tmp = 1;
311 : :
312 : 808 : interval = (u64) tmp;
313 : 808 : tk->cycle_interval = interval;
314 : :
315 : : /* Go back from cycles -> shifted ns */
316 : 808 : tk->xtime_interval = interval * clock->mult;
317 : 808 : tk->xtime_remainder = ntpinterval - tk->xtime_interval;
318 : 808 : tk->raw_interval = interval * clock->mult;
319 : :
320 : : /* if changing clocks, convert xtime_nsec shift units */
321 [ + + ]: 808 : if (old_clock) {
322 : 404 : int shift_change = clock->shift - old_clock->shift;
323 [ - + ]: 404 : if (shift_change < 0) {
324 : 0 : tk->tkr_mono.xtime_nsec >>= -shift_change;
325 : 0 : tk->tkr_raw.xtime_nsec >>= -shift_change;
326 : : } else {
327 : 404 : tk->tkr_mono.xtime_nsec <<= shift_change;
328 : 404 : tk->tkr_raw.xtime_nsec <<= shift_change;
329 : : }
330 : : }
331 : :
332 : 808 : tk->tkr_mono.shift = clock->shift;
333 : 808 : tk->tkr_raw.shift = clock->shift;
334 : :
335 : 808 : tk->ntp_error = 0;
336 : 808 : tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
337 : 808 : tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
338 : :
339 : : /*
340 : : * The timekeeper keeps its own mult values for the currently
341 : : * active clocksource. These value will be adjusted via NTP
342 : : * to counteract clock drifting.
343 : : */
344 : 808 : tk->tkr_mono.mult = clock->mult;
345 : 808 : tk->tkr_raw.mult = clock->mult;
346 : 808 : tk->ntp_err_mult = 0;
347 : 808 : tk->skip_second_overflow = 0;
348 : 808 : }
349 : :
350 : : /* Timekeeper helper functions. */
351 : :
352 : : #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
353 : : static u32 default_arch_gettimeoffset(void) { return 0; }
354 : : u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
355 : : #else
356 : : static inline u32 arch_gettimeoffset(void) { return 0; }
357 : : #endif
358 : :
359 : 6133868 : static inline u64 timekeeping_delta_to_ns(const struct tk_read_base *tkr, u64 delta)
360 : : {
361 : : u64 nsec;
362 : :
363 : 498404992 : nsec = delta * tkr->mult + tkr->xtime_nsec;
364 : 498404992 : nsec >>= tkr->shift;
365 : :
366 : : /* If arch requires, add in get_arch_timeoffset() */
367 : 6133868 : return nsec + arch_gettimeoffset();
368 : : }
369 : :
370 : 491305412 : static inline u64 timekeeping_get_ns(const struct tk_read_base *tkr)
371 : : {
372 : : u64 delta;
373 : :
374 : : delta = timekeeping_get_delta(tkr);
375 : 492271124 : return timekeeping_delta_to_ns(tkr, delta);
376 : : }
377 : :
378 : : static inline u64 timekeeping_cycles_to_ns(const struct tk_read_base *tkr, u64 cycles)
379 : : {
380 : : u64 delta;
381 : :
382 : : /* calculate the delta since the last update_wall_time */
383 : 0 : delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
384 : : return timekeeping_delta_to_ns(tkr, delta);
385 : : }
386 : :
387 : : /**
388 : : * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
389 : : * @tkr: Timekeeping readout base from which we take the update
390 : : *
391 : : * We want to use this from any context including NMI and tracing /
392 : : * instrumenting the timekeeping code itself.
393 : : *
394 : : * Employ the latch technique; see @raw_write_seqcount_latch.
395 : : *
396 : : * So if a NMI hits the update of base[0] then it will use base[1]
397 : : * which is still consistent. In the worst case this can result is a
398 : : * slightly wrong timestamp (a few nanoseconds). See
399 : : * @ktime_get_mono_fast_ns.
400 : : */
401 : 10018704 : static void update_fast_timekeeper(const struct tk_read_base *tkr,
402 : : struct tk_fast *tkf)
403 : : {
404 : 10018704 : struct tk_read_base *base = tkf->base;
405 : :
406 : : /* Force readers off to base[1] */
407 : : raw_write_seqcount_latch(&tkf->seq);
408 : :
409 : : /* Update base[0] */
410 : 10018704 : memcpy(base, tkr, sizeof(*base));
411 : :
412 : : /* Force readers back to base[0] */
413 : : raw_write_seqcount_latch(&tkf->seq);
414 : :
415 : : /* Update base[1] */
416 : 10018704 : memcpy(base + 1, base, sizeof(*base));
417 : 10018704 : }
418 : :
419 : : /**
420 : : * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
421 : : *
422 : : * This timestamp is not guaranteed to be monotonic across an update.
423 : : * The timestamp is calculated by:
424 : : *
425 : : * now = base_mono + clock_delta * slope
426 : : *
427 : : * So if the update lowers the slope, readers who are forced to the
428 : : * not yet updated second array are still using the old steeper slope.
429 : : *
430 : : * tmono
431 : : * ^
432 : : * | o n
433 : : * | o n
434 : : * | u
435 : : * | o
436 : : * |o
437 : : * |12345678---> reader order
438 : : *
439 : : * o = old slope
440 : : * u = update
441 : : * n = new slope
442 : : *
443 : : * So reader 6 will observe time going backwards versus reader 5.
444 : : *
445 : : * While other CPUs are likely to be able observe that, the only way
446 : : * for a CPU local observation is when an NMI hits in the middle of
447 : : * the update. Timestamps taken from that NMI context might be ahead
448 : : * of the following timestamps. Callers need to be aware of that and
449 : : * deal with it.
450 : : */
451 : : static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
452 : : {
453 : : struct tk_read_base *tkr;
454 : : unsigned int seq;
455 : : u64 now;
456 : :
457 : : do {
458 : 6133876 : seq = raw_read_seqcount_latch(&tkf->seq);
459 : 6133870 : tkr = tkf->base + (seq & 0x01);
460 : 6133870 : now = ktime_to_ns(tkr->base);
461 : :
462 : 6133866 : now += timekeeping_delta_to_ns(tkr,
463 : : clocksource_delta(
464 : : tk_clock_read(tkr),
465 : : tkr->cycle_last,
466 : : tkr->mask));
467 [ # # + + ]: 6133866 : } while (read_seqcount_retry(&tkf->seq, seq));
468 : :
469 : 6131538 : return now;
470 : : }
471 : :
472 : 6131546 : u64 ktime_get_mono_fast_ns(void)
473 : : {
474 : 6131538 : return __ktime_get_fast_ns(&tk_fast_mono);
475 : : }
476 : : EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
477 : :
478 : 0 : u64 ktime_get_raw_fast_ns(void)
479 : : {
480 : 0 : return __ktime_get_fast_ns(&tk_fast_raw);
481 : : }
482 : : EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
483 : :
484 : : /**
485 : : * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
486 : : *
487 : : * To keep it NMI safe since we're accessing from tracing, we're not using a
488 : : * separate timekeeper with updates to monotonic clock and boot offset
489 : : * protected with seqlocks. This has the following minor side effects:
490 : : *
491 : : * (1) Its possible that a timestamp be taken after the boot offset is updated
492 : : * but before the timekeeper is updated. If this happens, the new boot offset
493 : : * is added to the old timekeeping making the clock appear to update slightly
494 : : * earlier:
495 : : * CPU 0 CPU 1
496 : : * timekeeping_inject_sleeptime64()
497 : : * __timekeeping_inject_sleeptime(tk, delta);
498 : : * timestamp();
499 : : * timekeeping_update(tk, TK_CLEAR_NTP...);
500 : : *
501 : : * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
502 : : * partially updated. Since the tk->offs_boot update is a rare event, this
503 : : * should be a rare occurrence which postprocessing should be able to handle.
504 : : */
505 : 0 : u64 notrace ktime_get_boot_fast_ns(void)
506 : : {
507 : : struct timekeeper *tk = &tk_core.timekeeper;
508 : :
509 : 0 : return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
510 : : }
511 : : EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
512 : :
513 : :
514 : : /*
515 : : * See comment for __ktime_get_fast_ns() vs. timestamp ordering
516 : : */
517 : : static __always_inline u64 __ktime_get_real_fast_ns(struct tk_fast *tkf)
518 : : {
519 : : struct tk_read_base *tkr;
520 : : unsigned int seq;
521 : : u64 now;
522 : :
523 : : do {
524 : 0 : seq = raw_read_seqcount_latch(&tkf->seq);
525 : 0 : tkr = tkf->base + (seq & 0x01);
526 : 0 : now = ktime_to_ns(tkr->base_real);
527 : :
528 : 0 : now += timekeeping_delta_to_ns(tkr,
529 : : clocksource_delta(
530 : : tk_clock_read(tkr),
531 : : tkr->cycle_last,
532 : : tkr->mask));
533 [ # # ]: 0 : } while (read_seqcount_retry(&tkf->seq, seq));
534 : :
535 : 0 : return now;
536 : : }
537 : :
538 : : /**
539 : : * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime.
540 : : */
541 : 0 : u64 ktime_get_real_fast_ns(void)
542 : : {
543 : 0 : return __ktime_get_real_fast_ns(&tk_fast_mono);
544 : : }
545 : : EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
546 : :
547 : : /**
548 : : * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
549 : : * @tk: Timekeeper to snapshot.
550 : : *
551 : : * It generally is unsafe to access the clocksource after timekeeping has been
552 : : * suspended, so take a snapshot of the readout base of @tk and use it as the
553 : : * fast timekeeper's readout base while suspended. It will return the same
554 : : * number of cycles every time until timekeeping is resumed at which time the
555 : : * proper readout base for the fast timekeeper will be restored automatically.
556 : : */
557 : 0 : static void halt_fast_timekeeper(const struct timekeeper *tk)
558 : : {
559 : : static struct tk_read_base tkr_dummy;
560 : 0 : const struct tk_read_base *tkr = &tk->tkr_mono;
561 : :
562 : 0 : memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
563 : 0 : cycles_at_suspend = tk_clock_read(tkr);
564 : 0 : tkr_dummy.clock = &dummy_clock;
565 : 0 : tkr_dummy.base_real = tkr->base + tk->offs_real;
566 : 0 : update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
567 : :
568 : 0 : tkr = &tk->tkr_raw;
569 : 0 : memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
570 : 0 : tkr_dummy.clock = &dummy_clock;
571 : 0 : update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
572 : 0 : }
573 : :
574 : : static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
575 : :
576 : : static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
577 : : {
578 : 5009344 : raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
579 : : }
580 : :
581 : : /**
582 : : * pvclock_gtod_register_notifier - register a pvclock timedata update listener
583 : : */
584 : 0 : int pvclock_gtod_register_notifier(struct notifier_block *nb)
585 : : {
586 : : struct timekeeper *tk = &tk_core.timekeeper;
587 : : unsigned long flags;
588 : : int ret;
589 : :
590 : 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
591 : 0 : ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
592 : : update_pvclock_gtod(tk, true);
593 : 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
594 : :
595 : 0 : return ret;
596 : : }
597 : : EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
598 : :
599 : : /**
600 : : * pvclock_gtod_unregister_notifier - unregister a pvclock
601 : : * timedata update listener
602 : : */
603 : 0 : int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
604 : : {
605 : : unsigned long flags;
606 : : int ret;
607 : :
608 : 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
609 : 0 : ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
610 : 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
611 : :
612 : 0 : return ret;
613 : : }
614 : : EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
615 : :
616 : : /*
617 : : * tk_update_leap_state - helper to update the next_leap_ktime
618 : : */
619 : 5009848 : static inline void tk_update_leap_state(struct timekeeper *tk)
620 : : {
621 : 5009848 : tk->next_leap_ktime = ntp_get_next_leap();
622 [ - + ]: 5009848 : if (tk->next_leap_ktime != KTIME_MAX)
623 : : /* Convert to monotonic time */
624 : 0 : tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
625 : 5009848 : }
626 : :
627 : : /*
628 : : * Update the ktime_t based scalar nsec members of the timekeeper
629 : : */
630 : 5009344 : static inline void tk_update_ktime_data(struct timekeeper *tk)
631 : : {
632 : : u64 seconds;
633 : : u32 nsec;
634 : :
635 : : /*
636 : : * The xtime based monotonic readout is:
637 : : * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
638 : : * The ktime based monotonic readout is:
639 : : * nsec = base_mono + now();
640 : : * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
641 : : */
642 : 5009344 : seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
643 : 5009344 : nsec = (u32) tk->wall_to_monotonic.tv_nsec;
644 : 10018688 : tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
645 : :
646 : : /*
647 : : * The sum of the nanoseconds portions of xtime and
648 : : * wall_to_monotonic can be greater/equal one second. Take
649 : : * this into account before updating tk->ktime_sec.
650 : : */
651 : 5009344 : nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
652 [ + + ]: 5009344 : if (nsec >= NSEC_PER_SEC)
653 : 2451044 : seconds++;
654 : 5009344 : tk->ktime_sec = seconds;
655 : :
656 : : /* Update the monotonic raw base */
657 : 10018688 : tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC);
658 : 5009344 : }
659 : :
660 : : /* must hold timekeeper_lock */
661 : 5009344 : static void timekeeping_update(struct timekeeper *tk, unsigned int action)
662 : : {
663 [ + + ]: 5009344 : if (action & TK_CLEAR_NTP) {
664 : 1622 : tk->ntp_error = 0;
665 : 1622 : ntp_clear();
666 : : }
667 : :
668 : 5009344 : tk_update_leap_state(tk);
669 : 5009344 : tk_update_ktime_data(tk);
670 : :
671 : 5009344 : update_vsyscall(tk);
672 : 5009344 : update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
673 : :
674 : 5009344 : tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real;
675 : 5009344 : update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
676 : 5009344 : update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
677 : :
678 [ + + ]: 5009344 : if (action & TK_CLOCK_WAS_SET)
679 : 2026 : tk->clock_was_set_seq++;
680 : : /*
681 : : * The mirroring of the data to the shadow-timekeeper needs
682 : : * to happen last here to ensure we don't over-write the
683 : : * timekeeper structure on the next update with stale data
684 : : */
685 [ + + ]: 5009344 : if (action & TK_MIRROR)
686 : 2026 : memcpy(&shadow_timekeeper, &tk_core.timekeeper,
687 : : sizeof(tk_core.timekeeper));
688 : 5009344 : }
689 : :
690 : : /**
691 : : * timekeeping_forward_now - update clock to the current time
692 : : *
693 : : * Forward the current clock to update its state since the last call to
694 : : * update_wall_time(). This is useful before significant clock changes,
695 : : * as it avoids having to deal with this time offset explicitly.
696 : : */
697 : 1622 : static void timekeeping_forward_now(struct timekeeper *tk)
698 : : {
699 : : u64 cycle_now, delta;
700 : :
701 : : cycle_now = tk_clock_read(&tk->tkr_mono);
702 : 1622 : delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
703 : 1622 : tk->tkr_mono.cycle_last = cycle_now;
704 : 1622 : tk->tkr_raw.cycle_last = cycle_now;
705 : :
706 : 1622 : tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
707 : :
708 : : /* If arch requires, add in get_arch_timeoffset() */
709 : : tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
710 : :
711 : :
712 : 1622 : tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;
713 : :
714 : : /* If arch requires, add in get_arch_timeoffset() */
715 : : tk->tkr_raw.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_raw.shift;
716 : :
717 : 1622 : tk_normalize_xtime(tk);
718 : 1622 : }
719 : :
720 : : /**
721 : : * ktime_get_real_ts64 - Returns the time of day in a timespec64.
722 : : * @ts: pointer to the timespec to be set
723 : : *
724 : : * Returns the time of day in a timespec64 (WARN if suspended).
725 : : */
726 : 304468 : void ktime_get_real_ts64(struct timespec64 *ts)
727 : : {
728 : : struct timekeeper *tk = &tk_core.timekeeper;
729 : : unsigned int seq;
730 : : u64 nsecs;
731 : :
732 [ - + ]: 304468 : WARN_ON(timekeeping_suspended);
733 : :
734 : : do {
735 : : seq = read_seqcount_begin(&tk_core.seq);
736 : :
737 : 304834 : ts->tv_sec = tk->xtime_sec;
738 : 304834 : nsecs = timekeeping_get_ns(&tk->tkr_mono);
739 : :
740 [ + + ]: 304834 : } while (read_seqcount_retry(&tk_core.seq, seq));
741 : :
742 : 304468 : ts->tv_nsec = 0;
743 : : timespec64_add_ns(ts, nsecs);
744 : 304468 : }
745 : : EXPORT_SYMBOL(ktime_get_real_ts64);
746 : :
747 : 470053034 : ktime_t ktime_get(void)
748 : : {
749 : : struct timekeeper *tk = &tk_core.timekeeper;
750 : : unsigned int seq;
751 : : ktime_t base;
752 : : u64 nsecs;
753 : :
754 [ - + ]: 470053034 : WARN_ON(timekeeping_suspended);
755 : :
756 : : do {
757 : : seq = read_seqcount_begin(&tk_core.seq);
758 : 469816386 : base = tk->tkr_mono.base;
759 : 469816386 : nsecs = timekeeping_get_ns(&tk->tkr_mono);
760 : :
761 [ + + ]: 470360010 : } while (read_seqcount_retry(&tk_core.seq, seq));
762 : :
763 : 469976780 : return ktime_add_ns(base, nsecs);
764 : : }
765 : : EXPORT_SYMBOL_GPL(ktime_get);
766 : :
767 : 0 : u32 ktime_get_resolution_ns(void)
768 : : {
769 : : struct timekeeper *tk = &tk_core.timekeeper;
770 : : unsigned int seq;
771 : : u32 nsecs;
772 : :
773 [ # # ]: 0 : WARN_ON(timekeeping_suspended);
774 : :
775 : : do {
776 : : seq = read_seqcount_begin(&tk_core.seq);
777 : 0 : nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
778 [ # # ]: 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
779 : :
780 : 0 : return nsecs;
781 : : }
782 : : EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
783 : :
784 : : static ktime_t *offsets[TK_OFFS_MAX] = {
785 : : [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
786 : : [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
787 : : [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
788 : : };
789 : :
790 : 2546006 : ktime_t ktime_get_with_offset(enum tk_offsets offs)
791 : : {
792 : : struct timekeeper *tk = &tk_core.timekeeper;
793 : : unsigned int seq;
794 : 2546006 : ktime_t base, *offset = offsets[offs];
795 : : u64 nsecs;
796 : :
797 [ - + ]: 2546006 : WARN_ON(timekeeping_suspended);
798 : :
799 : : do {
800 : : seq = read_seqcount_begin(&tk_core.seq);
801 : 2548724 : base = ktime_add(tk->tkr_mono.base, *offset);
802 : 2548724 : nsecs = timekeeping_get_ns(&tk->tkr_mono);
803 : :
804 [ + + ]: 2549070 : } while (read_seqcount_retry(&tk_core.seq, seq));
805 : :
806 : 2546086 : return ktime_add_ns(base, nsecs);
807 : :
808 : : }
809 : : EXPORT_SYMBOL_GPL(ktime_get_with_offset);
810 : :
811 : 0 : ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs)
812 : : {
813 : : struct timekeeper *tk = &tk_core.timekeeper;
814 : : unsigned int seq;
815 : 0 : ktime_t base, *offset = offsets[offs];
816 : : u64 nsecs;
817 : :
818 [ # # ]: 0 : WARN_ON(timekeeping_suspended);
819 : :
820 : : do {
821 : : seq = read_seqcount_begin(&tk_core.seq);
822 : 0 : base = ktime_add(tk->tkr_mono.base, *offset);
823 : 0 : nsecs = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
824 : :
825 [ # # ]: 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
826 : :
827 : 0 : return ktime_add_ns(base, nsecs);
828 : : }
829 : : EXPORT_SYMBOL_GPL(ktime_get_coarse_with_offset);
830 : :
831 : : /**
832 : : * ktime_mono_to_any() - convert mononotic time to any other time
833 : : * @tmono: time to convert.
834 : : * @offs: which offset to use
835 : : */
836 : 23696 : ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
837 : : {
838 : 23696 : ktime_t *offset = offsets[offs];
839 : : unsigned int seq;
840 : : ktime_t tconv;
841 : :
842 : : do {
843 : : seq = read_seqcount_begin(&tk_core.seq);
844 : 23706 : tconv = ktime_add(tmono, *offset);
845 [ + + ]: 23708 : } while (read_seqcount_retry(&tk_core.seq, seq));
846 : :
847 : 23702 : return tconv;
848 : : }
849 : : EXPORT_SYMBOL_GPL(ktime_mono_to_any);
850 : :
851 : : /**
852 : : * ktime_get_raw - Returns the raw monotonic time in ktime_t format
853 : : */
854 : 0 : ktime_t ktime_get_raw(void)
855 : : {
856 : : struct timekeeper *tk = &tk_core.timekeeper;
857 : : unsigned int seq;
858 : : ktime_t base;
859 : : u64 nsecs;
860 : :
861 : : do {
862 : : seq = read_seqcount_begin(&tk_core.seq);
863 : 0 : base = tk->tkr_raw.base;
864 : 0 : nsecs = timekeeping_get_ns(&tk->tkr_raw);
865 : :
866 [ # # ]: 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
867 : :
868 : 0 : return ktime_add_ns(base, nsecs);
869 : : }
870 : : EXPORT_SYMBOL_GPL(ktime_get_raw);
871 : :
872 : : /**
873 : : * ktime_get_ts64 - get the monotonic clock in timespec64 format
874 : : * @ts: pointer to timespec variable
875 : : *
876 : : * The function calculates the monotonic clock from the realtime
877 : : * clock and the wall_to_monotonic offset and stores the result
878 : : * in normalized timespec64 format in the variable pointed to by @ts.
879 : : */
880 : 1701360 : void ktime_get_ts64(struct timespec64 *ts)
881 : : {
882 : : struct timekeeper *tk = &tk_core.timekeeper;
883 : : struct timespec64 tomono;
884 : : unsigned int seq;
885 : : u64 nsec;
886 : :
887 [ - + ]: 1701360 : WARN_ON(timekeeping_suspended);
888 : :
889 : : do {
890 : : seq = read_seqcount_begin(&tk_core.seq);
891 : 1702544 : ts->tv_sec = tk->xtime_sec;
892 : 1702544 : nsec = timekeeping_get_ns(&tk->tkr_mono);
893 : 1702558 : tomono = tk->wall_to_monotonic;
894 : :
895 [ + + ]: 1702562 : } while (read_seqcount_retry(&tk_core.seq, seq));
896 : :
897 : 1701352 : ts->tv_sec += tomono.tv_sec;
898 : 1701352 : ts->tv_nsec = 0;
899 : 1701352 : timespec64_add_ns(ts, nsec + tomono.tv_nsec);
900 : 1701352 : }
901 : : EXPORT_SYMBOL_GPL(ktime_get_ts64);
902 : :
903 : : /**
904 : : * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
905 : : *
906 : : * Returns the seconds portion of CLOCK_MONOTONIC with a single non
907 : : * serialized read. tk->ktime_sec is of type 'unsigned long' so this
908 : : * works on both 32 and 64 bit systems. On 32 bit systems the readout
909 : : * covers ~136 years of uptime which should be enough to prevent
910 : : * premature wrap arounds.
911 : : */
912 : 0 : time64_t ktime_get_seconds(void)
913 : : {
914 : : struct timekeeper *tk = &tk_core.timekeeper;
915 : :
916 [ # # ]: 0 : WARN_ON(timekeeping_suspended);
917 : 0 : return tk->ktime_sec;
918 : : }
919 : : EXPORT_SYMBOL_GPL(ktime_get_seconds);
920 : :
921 : : /**
922 : : * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
923 : : *
924 : : * Returns the wall clock seconds since 1970. This replaces the
925 : : * get_seconds() interface which is not y2038 safe on 32bit systems.
926 : : *
927 : : * For 64bit systems the fast access to tk->xtime_sec is preserved. On
928 : : * 32bit systems the access must be protected with the sequence
929 : : * counter to provide "atomic" access to the 64bit tk->xtime_sec
930 : : * value.
931 : : */
932 : 592146 : time64_t ktime_get_real_seconds(void)
933 : : {
934 : : struct timekeeper *tk = &tk_core.timekeeper;
935 : : time64_t seconds;
936 : : unsigned int seq;
937 : :
938 : : if (IS_ENABLED(CONFIG_64BIT))
939 : : return tk->xtime_sec;
940 : :
941 : : do {
942 : : seq = read_seqcount_begin(&tk_core.seq);
943 : 592186 : seconds = tk->xtime_sec;
944 : :
945 [ + + ]: 592186 : } while (read_seqcount_retry(&tk_core.seq, seq));
946 : :
947 : 592152 : return seconds;
948 : : }
949 : : EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
950 : :
951 : : /**
952 : : * __ktime_get_real_seconds - The same as ktime_get_real_seconds
953 : : * but without the sequence counter protect. This internal function
954 : : * is called just when timekeeping lock is already held.
955 : : */
956 : 300 : time64_t __ktime_get_real_seconds(void)
957 : : {
958 : : struct timekeeper *tk = &tk_core.timekeeper;
959 : :
960 : 300 : return tk->xtime_sec;
961 : : }
962 : :
963 : : /**
964 : : * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
965 : : * @systime_snapshot: pointer to struct receiving the system time snapshot
966 : : */
967 : 0 : void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
968 : : {
969 : : struct timekeeper *tk = &tk_core.timekeeper;
970 : : unsigned int seq;
971 : : ktime_t base_raw;
972 : : ktime_t base_real;
973 : : u64 nsec_raw;
974 : : u64 nsec_real;
975 : : u64 now;
976 : :
977 [ # # # # ]: 0 : WARN_ON_ONCE(timekeeping_suspended);
978 : :
979 : : do {
980 : : seq = read_seqcount_begin(&tk_core.seq);
981 : : now = tk_clock_read(&tk->tkr_mono);
982 : 0 : systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
983 : 0 : systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
984 : 0 : base_real = ktime_add(tk->tkr_mono.base,
985 : : tk_core.timekeeper.offs_real);
986 : 0 : base_raw = tk->tkr_raw.base;
987 : : nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
988 : : nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
989 [ # # ]: 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
990 : :
991 : 0 : systime_snapshot->cycles = now;
992 : 0 : systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
993 : 0 : systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
994 : 0 : }
995 : : EXPORT_SYMBOL_GPL(ktime_get_snapshot);
996 : :
997 : : /* Scale base by mult/div checking for overflow */
998 : 0 : static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
999 : : {
1000 : : u64 tmp, rem;
1001 : :
1002 : 0 : tmp = div64_u64_rem(*base, div, &rem);
1003 : :
1004 [ # # # # ]: 0 : if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
1005 : 0 : ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
1006 : : return -EOVERFLOW;
1007 : 0 : tmp *= mult;
1008 : 0 : rem *= mult;
1009 : :
1010 [ # # # # : 0 : do_div(rem, div);
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # ]
1011 : 0 : *base = tmp + rem;
1012 : 0 : return 0;
1013 : : }
1014 : :
1015 : : /**
1016 : : * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
1017 : : * @history: Snapshot representing start of history
1018 : : * @partial_history_cycles: Cycle offset into history (fractional part)
1019 : : * @total_history_cycles: Total history length in cycles
1020 : : * @discontinuity: True indicates clock was set on history period
1021 : : * @ts: Cross timestamp that should be adjusted using
1022 : : * partial/total ratio
1023 : : *
1024 : : * Helper function used by get_device_system_crosststamp() to correct the
1025 : : * crosstimestamp corresponding to the start of the current interval to the
1026 : : * system counter value (timestamp point) provided by the driver. The
1027 : : * total_history_* quantities are the total history starting at the provided
1028 : : * reference point and ending at the start of the current interval. The cycle
1029 : : * count between the driver timestamp point and the start of the current
1030 : : * interval is partial_history_cycles.
1031 : : */
1032 : 0 : static int adjust_historical_crosststamp(struct system_time_snapshot *history,
1033 : : u64 partial_history_cycles,
1034 : : u64 total_history_cycles,
1035 : : bool discontinuity,
1036 : : struct system_device_crosststamp *ts)
1037 : : {
1038 : : struct timekeeper *tk = &tk_core.timekeeper;
1039 : : u64 corr_raw, corr_real;
1040 : : bool interp_forward;
1041 : : int ret;
1042 : :
1043 [ # # ]: 0 : if (total_history_cycles == 0 || partial_history_cycles == 0)
1044 : : return 0;
1045 : :
1046 : : /* Interpolate shortest distance from beginning or end of history */
1047 : 0 : interp_forward = partial_history_cycles > total_history_cycles / 2;
1048 : : partial_history_cycles = interp_forward ?
1049 [ # # ]: 0 : total_history_cycles - partial_history_cycles :
1050 : : partial_history_cycles;
1051 : :
1052 : : /*
1053 : : * Scale the monotonic raw time delta by:
1054 : : * partial_history_cycles / total_history_cycles
1055 : : */
1056 : 0 : corr_raw = (u64)ktime_to_ns(
1057 : 0 : ktime_sub(ts->sys_monoraw, history->raw));
1058 : 0 : ret = scale64_check_overflow(partial_history_cycles,
1059 : : total_history_cycles, &corr_raw);
1060 [ # # ]: 0 : if (ret)
1061 : : return ret;
1062 : :
1063 : : /*
1064 : : * If there is a discontinuity in the history, scale monotonic raw
1065 : : * correction by:
1066 : : * mult(real)/mult(raw) yielding the realtime correction
1067 : : * Otherwise, calculate the realtime correction similar to monotonic
1068 : : * raw calculation
1069 : : */
1070 [ # # ]: 0 : if (discontinuity) {
1071 : 0 : corr_real = mul_u64_u32_div
1072 : : (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1073 : : } else {
1074 : 0 : corr_real = (u64)ktime_to_ns(
1075 : 0 : ktime_sub(ts->sys_realtime, history->real));
1076 : 0 : ret = scale64_check_overflow(partial_history_cycles,
1077 : : total_history_cycles, &corr_real);
1078 [ # # ]: 0 : if (ret)
1079 : : return ret;
1080 : : }
1081 : :
1082 : : /* Fixup monotonic raw and real time time values */
1083 [ # # ]: 0 : if (interp_forward) {
1084 : 0 : ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1085 : 0 : ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1086 : : } else {
1087 : 0 : ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1088 : 0 : ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1089 : : }
1090 : :
1091 : : return 0;
1092 : : }
1093 : :
1094 : : /*
1095 : : * cycle_between - true if test occurs chronologically between before and after
1096 : : */
1097 : : static bool cycle_between(u64 before, u64 test, u64 after)
1098 : : {
1099 [ # # # # ]: 0 : if (test > before && test < after)
1100 : : return true;
1101 [ # # # # ]: 0 : if (test < before && before > after)
1102 : : return true;
1103 : : return false;
1104 : : }
1105 : :
1106 : : /**
1107 : : * get_device_system_crosststamp - Synchronously capture system/device timestamp
1108 : : * @get_time_fn: Callback to get simultaneous device time and
1109 : : * system counter from the device driver
1110 : : * @ctx: Context passed to get_time_fn()
1111 : : * @history_begin: Historical reference point used to interpolate system
1112 : : * time when counter provided by the driver is before the current interval
1113 : : * @xtstamp: Receives simultaneously captured system and device time
1114 : : *
1115 : : * Reads a timestamp from a device and correlates it to system time
1116 : : */
1117 : 0 : int get_device_system_crosststamp(int (*get_time_fn)
1118 : : (ktime_t *device_time,
1119 : : struct system_counterval_t *sys_counterval,
1120 : : void *ctx),
1121 : : void *ctx,
1122 : : struct system_time_snapshot *history_begin,
1123 : : struct system_device_crosststamp *xtstamp)
1124 : : {
1125 : : struct system_counterval_t system_counterval;
1126 : : struct timekeeper *tk = &tk_core.timekeeper;
1127 : : u64 cycles, now, interval_start;
1128 : : unsigned int clock_was_set_seq = 0;
1129 : : ktime_t base_real, base_raw;
1130 : : u64 nsec_real, nsec_raw;
1131 : : u8 cs_was_changed_seq;
1132 : : unsigned int seq;
1133 : : bool do_interp;
1134 : : int ret;
1135 : :
1136 : : do {
1137 : : seq = read_seqcount_begin(&tk_core.seq);
1138 : : /*
1139 : : * Try to synchronously capture device time and a system
1140 : : * counter value calling back into the device driver
1141 : : */
1142 : 0 : ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1143 [ # # ]: 0 : if (ret)
1144 : 0 : return ret;
1145 : :
1146 : : /*
1147 : : * Verify that the clocksource associated with the captured
1148 : : * system counter value is the same as the currently installed
1149 : : * timekeeper clocksource
1150 : : */
1151 [ # # ]: 0 : if (tk->tkr_mono.clock != system_counterval.cs)
1152 : : return -ENODEV;
1153 : 0 : cycles = system_counterval.cycles;
1154 : :
1155 : : /*
1156 : : * Check whether the system counter value provided by the
1157 : : * device driver is on the current timekeeping interval.
1158 : : */
1159 : : now = tk_clock_read(&tk->tkr_mono);
1160 : 0 : interval_start = tk->tkr_mono.cycle_last;
1161 [ # # ]: 0 : if (!cycle_between(interval_start, cycles, now)) {
1162 : 0 : clock_was_set_seq = tk->clock_was_set_seq;
1163 : 0 : cs_was_changed_seq = tk->cs_was_changed_seq;
1164 : : cycles = interval_start;
1165 : : do_interp = true;
1166 : : } else {
1167 : : do_interp = false;
1168 : : }
1169 : :
1170 : 0 : base_real = ktime_add(tk->tkr_mono.base,
1171 : : tk_core.timekeeper.offs_real);
1172 : 0 : base_raw = tk->tkr_raw.base;
1173 : :
1174 : 0 : nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1175 : : system_counterval.cycles);
1176 : : nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1177 : : system_counterval.cycles);
1178 [ # # ]: 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
1179 : :
1180 : 0 : xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1181 : 0 : xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1182 : :
1183 : : /*
1184 : : * Interpolate if necessary, adjusting back from the start of the
1185 : : * current interval
1186 : : */
1187 [ # # ]: 0 : if (do_interp) {
1188 : : u64 partial_history_cycles, total_history_cycles;
1189 : : bool discontinuity;
1190 : :
1191 : : /*
1192 : : * Check that the counter value occurs after the provided
1193 : : * history reference and that the history doesn't cross a
1194 : : * clocksource change
1195 : : */
1196 [ # # # # ]: 0 : if (!history_begin ||
1197 : 0 : !cycle_between(history_begin->cycles,
1198 [ # # ]: 0 : system_counterval.cycles, cycles) ||
1199 : 0 : history_begin->cs_was_changed_seq != cs_was_changed_seq)
1200 : : return -EINVAL;
1201 : 0 : partial_history_cycles = cycles - system_counterval.cycles;
1202 : 0 : total_history_cycles = cycles - history_begin->cycles;
1203 : 0 : discontinuity =
1204 : 0 : history_begin->clock_was_set_seq != clock_was_set_seq;
1205 : :
1206 : 0 : ret = adjust_historical_crosststamp(history_begin,
1207 : : partial_history_cycles,
1208 : : total_history_cycles,
1209 : : discontinuity, xtstamp);
1210 [ # # ]: 0 : if (ret)
1211 : 0 : return ret;
1212 : : }
1213 : :
1214 : : return 0;
1215 : : }
1216 : : EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1217 : :
1218 : : /**
1219 : : * do_settimeofday64 - Sets the time of day.
1220 : : * @ts: pointer to the timespec64 variable containing the new time
1221 : : *
1222 : : * Sets the time of day to the new time and update NTP and notify hrtimers
1223 : : */
1224 : 814 : int do_settimeofday64(const struct timespec64 *ts)
1225 : : {
1226 : : struct timekeeper *tk = &tk_core.timekeeper;
1227 : : struct timespec64 ts_delta, xt;
1228 : : unsigned long flags;
1229 : : int ret = 0;
1230 : :
1231 [ + - ]: 814 : if (!timespec64_valid_settod(ts))
1232 : : return -EINVAL;
1233 : :
1234 : 814 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1235 : : write_seqcount_begin(&tk_core.seq);
1236 : :
1237 : 814 : timekeeping_forward_now(tk);
1238 : :
1239 : : xt = tk_xtime(tk);
1240 : 814 : ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
1241 : 814 : ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
1242 : :
1243 [ + - ]: 814 : if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1244 : : ret = -EINVAL;
1245 : : goto out;
1246 : : }
1247 : :
1248 : 814 : tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1249 : :
1250 : : tk_set_xtime(tk, ts);
1251 : : out:
1252 : 814 : timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1253 : :
1254 : : write_seqcount_end(&tk_core.seq);
1255 : 814 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1256 : :
1257 : : /* signal hrtimers about time change */
1258 : 814 : clock_was_set();
1259 : :
1260 [ + - ]: 814 : if (!ret)
1261 : 814 : audit_tk_injoffset(ts_delta);
1262 : :
1263 : 814 : return ret;
1264 : : }
1265 : : EXPORT_SYMBOL(do_settimeofday64);
1266 : :
1267 : : /**
1268 : : * timekeeping_inject_offset - Adds or subtracts from the current time.
1269 : : * @tv: pointer to the timespec variable containing the offset
1270 : : *
1271 : : * Adds or subtracts an offset value from the current time.
1272 : : */
1273 : 404 : static int timekeeping_inject_offset(const struct timespec64 *ts)
1274 : : {
1275 : : struct timekeeper *tk = &tk_core.timekeeper;
1276 : : unsigned long flags;
1277 : : struct timespec64 tmp;
1278 : : int ret = 0;
1279 : :
1280 [ + - ]: 404 : if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
1281 : : return -EINVAL;
1282 : :
1283 : 404 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1284 : : write_seqcount_begin(&tk_core.seq);
1285 : :
1286 : 404 : timekeeping_forward_now(tk);
1287 : :
1288 : : /* Make sure the proposed value is valid */
1289 : 404 : tmp = timespec64_add(tk_xtime(tk), *ts);
1290 [ + - + - ]: 808 : if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
1291 : : !timespec64_valid_settod(&tmp)) {
1292 : : ret = -EINVAL;
1293 : : goto error;
1294 : : }
1295 : :
1296 : 404 : tk_xtime_add(tk, ts);
1297 : 404 : tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *ts));
1298 : :
1299 : : error: /* even if we error out, we forwarded the time, so call update */
1300 : 404 : timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1301 : :
1302 : : write_seqcount_end(&tk_core.seq);
1303 : 404 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1304 : :
1305 : : /* signal hrtimers about time change */
1306 : 404 : clock_was_set();
1307 : :
1308 : 404 : return ret;
1309 : : }
1310 : :
1311 : : /*
1312 : : * Indicates if there is an offset between the system clock and the hardware
1313 : : * clock/persistent clock/rtc.
1314 : : */
1315 : : int persistent_clock_is_local;
1316 : :
1317 : : /*
1318 : : * Adjust the time obtained from the CMOS to be UTC time instead of
1319 : : * local time.
1320 : : *
1321 : : * This is ugly, but preferable to the alternatives. Otherwise we
1322 : : * would either need to write a program to do it in /etc/rc (and risk
1323 : : * confusion if the program gets run more than once; it would also be
1324 : : * hard to make the program warp the clock precisely n hours) or
1325 : : * compile in the timezone information into the kernel. Bad, bad....
1326 : : *
1327 : : * - TYT, 1992-01-01
1328 : : *
1329 : : * The best thing to do is to keep the CMOS clock in universal time (UTC)
1330 : : * as real UNIX machines always do it. This avoids all headaches about
1331 : : * daylight saving times and warping kernel clocks.
1332 : : */
1333 : 404 : void timekeeping_warp_clock(void)
1334 : : {
1335 [ - + ]: 404 : if (sys_tz.tz_minuteswest != 0) {
1336 : : struct timespec64 adjust;
1337 : :
1338 : 0 : persistent_clock_is_local = 1;
1339 : 0 : adjust.tv_sec = sys_tz.tz_minuteswest * 60;
1340 : 0 : adjust.tv_nsec = 0;
1341 : 0 : timekeeping_inject_offset(&adjust);
1342 : : }
1343 : 404 : }
1344 : :
1345 : : /**
1346 : : * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
1347 : : *
1348 : : */
1349 : : static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1350 : : {
1351 : 0 : tk->tai_offset = tai_offset;
1352 : 0 : tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1353 : : }
1354 : :
1355 : : /**
1356 : : * change_clocksource - Swaps clocksources if a new one is available
1357 : : *
1358 : : * Accumulates current time interval and initializes new clocksource
1359 : : */
1360 : 404 : static int change_clocksource(void *data)
1361 : : {
1362 : : struct timekeeper *tk = &tk_core.timekeeper;
1363 : : struct clocksource *new, *old;
1364 : : unsigned long flags;
1365 : :
1366 : : new = (struct clocksource *) data;
1367 : :
1368 : 404 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1369 : : write_seqcount_begin(&tk_core.seq);
1370 : :
1371 : 404 : timekeeping_forward_now(tk);
1372 : : /*
1373 : : * If the cs is in module, get a module reference. Succeeds
1374 : : * for built-in code (owner == NULL) as well.
1375 : : */
1376 [ + - ]: 404 : if (try_module_get(new->owner)) {
1377 [ - + # # ]: 404 : if (!new->enable || new->enable(new) == 0) {
1378 : 404 : old = tk->tkr_mono.clock;
1379 : 404 : tk_setup_internals(tk, new);
1380 [ - + ]: 404 : if (old->disable)
1381 : 0 : old->disable(old);
1382 : 404 : module_put(old->owner);
1383 : : } else {
1384 : 0 : module_put(new->owner);
1385 : : }
1386 : : }
1387 : 404 : timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1388 : :
1389 : : write_seqcount_end(&tk_core.seq);
1390 : 404 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1391 : :
1392 : 404 : return 0;
1393 : : }
1394 : :
1395 : : /**
1396 : : * timekeeping_notify - Install a new clock source
1397 : : * @clock: pointer to the clock source
1398 : : *
1399 : : * This function is called from clocksource.c after a new, better clock
1400 : : * source has been registered. The caller holds the clocksource_mutex.
1401 : : */
1402 : 404 : int timekeeping_notify(struct clocksource *clock)
1403 : : {
1404 : : struct timekeeper *tk = &tk_core.timekeeper;
1405 : :
1406 [ + - ]: 404 : if (tk->tkr_mono.clock == clock)
1407 : : return 0;
1408 : 404 : stop_machine(change_clocksource, clock, NULL);
1409 : 404 : tick_clock_notify();
1410 [ - + ]: 404 : return tk->tkr_mono.clock == clock ? 0 : -1;
1411 : : }
1412 : :
1413 : : /**
1414 : : * ktime_get_raw_ts64 - Returns the raw monotonic time in a timespec
1415 : : * @ts: pointer to the timespec64 to be set
1416 : : *
1417 : : * Returns the raw monotonic time (completely un-modified by ntp)
1418 : : */
1419 : 808 : void ktime_get_raw_ts64(struct timespec64 *ts)
1420 : : {
1421 : : struct timekeeper *tk = &tk_core.timekeeper;
1422 : : unsigned int seq;
1423 : : u64 nsecs;
1424 : :
1425 : : do {
1426 : : seq = read_seqcount_begin(&tk_core.seq);
1427 : 818 : ts->tv_sec = tk->raw_sec;
1428 : 818 : nsecs = timekeeping_get_ns(&tk->tkr_raw);
1429 : :
1430 [ + + ]: 818 : } while (read_seqcount_retry(&tk_core.seq, seq));
1431 : :
1432 : 808 : ts->tv_nsec = 0;
1433 : : timespec64_add_ns(ts, nsecs);
1434 : 808 : }
1435 : : EXPORT_SYMBOL(ktime_get_raw_ts64);
1436 : :
1437 : :
1438 : : /**
1439 : : * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1440 : : */
1441 : 3696 : int timekeeping_valid_for_hres(void)
1442 : : {
1443 : : struct timekeeper *tk = &tk_core.timekeeper;
1444 : : unsigned int seq;
1445 : : int ret;
1446 : :
1447 : : do {
1448 : : seq = read_seqcount_begin(&tk_core.seq);
1449 : :
1450 : 3696 : ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1451 : :
1452 [ - + ]: 3696 : } while (read_seqcount_retry(&tk_core.seq, seq));
1453 : :
1454 : 3696 : return ret;
1455 : : }
1456 : :
1457 : : /**
1458 : : * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1459 : : */
1460 : 27217410 : u64 timekeeping_max_deferment(void)
1461 : : {
1462 : : struct timekeeper *tk = &tk_core.timekeeper;
1463 : : unsigned int seq;
1464 : : u64 ret;
1465 : :
1466 : : do {
1467 : : seq = read_seqcount_begin(&tk_core.seq);
1468 : :
1469 : 27218174 : ret = tk->tkr_mono.clock->max_idle_ns;
1470 : :
1471 [ + + ]: 27218130 : } while (read_seqcount_retry(&tk_core.seq, seq));
1472 : :
1473 : 27217384 : return ret;
1474 : : }
1475 : :
1476 : : /**
1477 : : * read_persistent_clock64 - Return time from the persistent clock.
1478 : : *
1479 : : * Weak dummy function for arches that do not yet support it.
1480 : : * Reads the time from the battery backed persistent clock.
1481 : : * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1482 : : *
1483 : : * XXX - Do be sure to remove it once all arches implement it.
1484 : : */
1485 : 0 : void __weak read_persistent_clock64(struct timespec64 *ts)
1486 : : {
1487 : 0 : ts->tv_sec = 0;
1488 : 0 : ts->tv_nsec = 0;
1489 : 0 : }
1490 : :
1491 : : /**
1492 : : * read_persistent_wall_and_boot_offset - Read persistent clock, and also offset
1493 : : * from the boot.
1494 : : *
1495 : : * Weak dummy function for arches that do not yet support it.
1496 : : * wall_time - current time as returned by persistent clock
1497 : : * boot_offset - offset that is defined as wall_time - boot_time
1498 : : * The default function calculates offset based on the current value of
1499 : : * local_clock(). This way architectures that support sched_clock() but don't
1500 : : * support dedicated boot time clock will provide the best estimate of the
1501 : : * boot time.
1502 : : */
1503 : : void __weak __init
1504 : 404 : read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
1505 : : struct timespec64 *boot_offset)
1506 : : {
1507 : 404 : read_persistent_clock64(wall_time);
1508 : 404 : *boot_offset = ns_to_timespec64(local_clock());
1509 : 404 : }
1510 : :
1511 : : /*
1512 : : * Flag reflecting whether timekeeping_resume() has injected sleeptime.
1513 : : *
1514 : : * The flag starts of false and is only set when a suspend reaches
1515 : : * timekeeping_suspend(), timekeeping_resume() sets it to false when the
1516 : : * timekeeper clocksource is not stopping across suspend and has been
1517 : : * used to update sleep time. If the timekeeper clocksource has stopped
1518 : : * then the flag stays true and is used by the RTC resume code to decide
1519 : : * whether sleeptime must be injected and if so the flag gets false then.
1520 : : *
1521 : : * If a suspend fails before reaching timekeeping_resume() then the flag
1522 : : * stays false and prevents erroneous sleeptime injection.
1523 : : */
1524 : : static bool suspend_timing_needed;
1525 : :
1526 : : /* Flag for if there is a persistent clock on this platform */
1527 : : static bool persistent_clock_exists;
1528 : :
1529 : : /*
1530 : : * timekeeping_init - Initializes the clocksource and common timekeeping values
1531 : : */
1532 : 404 : void __init timekeeping_init(void)
1533 : : {
1534 : : struct timespec64 wall_time, boot_offset, wall_to_mono;
1535 : : struct timekeeper *tk = &tk_core.timekeeper;
1536 : : struct clocksource *clock;
1537 : : unsigned long flags;
1538 : :
1539 : 404 : read_persistent_wall_and_boot_offset(&wall_time, &boot_offset);
1540 [ + - - + ]: 808 : if (timespec64_valid_settod(&wall_time) &&
1541 : : timespec64_to_ns(&wall_time) > 0) {
1542 : 0 : persistent_clock_exists = true;
1543 [ - + ]: 404 : } else if (timespec64_to_ns(&wall_time) != 0) {
1544 : 0 : pr_warn("Persistent clock returned invalid value");
1545 : 0 : wall_time = (struct timespec64){0};
1546 : : }
1547 : :
1548 [ - + ]: 404 : if (timespec64_compare(&wall_time, &boot_offset) < 0)
1549 : 0 : boot_offset = (struct timespec64){0};
1550 : :
1551 : : /*
1552 : : * We want set wall_to_mono, so the following is true:
1553 : : * wall time + wall_to_mono = boot time
1554 : : */
1555 : : wall_to_mono = timespec64_sub(boot_offset, wall_time);
1556 : :
1557 : 404 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1558 : : write_seqcount_begin(&tk_core.seq);
1559 : 404 : ntp_init();
1560 : :
1561 : 404 : clock = clocksource_default_clock();
1562 [ - + ]: 404 : if (clock->enable)
1563 : 0 : clock->enable(clock);
1564 : 404 : tk_setup_internals(tk, clock);
1565 : :
1566 : : tk_set_xtime(tk, &wall_time);
1567 : 404 : tk->raw_sec = 0;
1568 : :
1569 : 404 : tk_set_wall_to_mono(tk, wall_to_mono);
1570 : :
1571 : 404 : timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1572 : :
1573 : : write_seqcount_end(&tk_core.seq);
1574 : 404 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1575 : 404 : }
1576 : :
1577 : : /* time in seconds when suspend began for persistent clock */
1578 : : static struct timespec64 timekeeping_suspend_time;
1579 : :
1580 : : /**
1581 : : * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1582 : : * @delta: pointer to a timespec delta value
1583 : : *
1584 : : * Takes a timespec offset measuring a suspend interval and properly
1585 : : * adds the sleep offset to the timekeeping variables.
1586 : : */
1587 : 0 : static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1588 : : const struct timespec64 *delta)
1589 : : {
1590 [ # # ]: 0 : if (!timespec64_valid_strict(delta)) {
1591 : 0 : printk_deferred(KERN_WARNING
1592 : : "__timekeeping_inject_sleeptime: Invalid "
1593 : : "sleep delta value!\n");
1594 : 0 : return;
1595 : : }
1596 : 0 : tk_xtime_add(tk, delta);
1597 : 0 : tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1598 : 0 : tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1599 : 0 : tk_debug_account_sleep_time(delta);
1600 : : }
1601 : :
1602 : : #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1603 : : /**
1604 : : * We have three kinds of time sources to use for sleep time
1605 : : * injection, the preference order is:
1606 : : * 1) non-stop clocksource
1607 : : * 2) persistent clock (ie: RTC accessible when irqs are off)
1608 : : * 3) RTC
1609 : : *
1610 : : * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1611 : : * If system has neither 1) nor 2), 3) will be used finally.
1612 : : *
1613 : : *
1614 : : * If timekeeping has injected sleeptime via either 1) or 2),
1615 : : * 3) becomes needless, so in this case we don't need to call
1616 : : * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1617 : : * means.
1618 : : */
1619 : : bool timekeeping_rtc_skipresume(void)
1620 : : {
1621 : : return !suspend_timing_needed;
1622 : : }
1623 : :
1624 : : /**
1625 : : * 1) can be determined whether to use or not only when doing
1626 : : * timekeeping_resume() which is invoked after rtc_suspend(),
1627 : : * so we can't skip rtc_suspend() surely if system has 1).
1628 : : *
1629 : : * But if system has 2), 2) will definitely be used, so in this
1630 : : * case we don't need to call rtc_suspend(), and this is what
1631 : : * timekeeping_rtc_skipsuspend() means.
1632 : : */
1633 : : bool timekeeping_rtc_skipsuspend(void)
1634 : : {
1635 : : return persistent_clock_exists;
1636 : : }
1637 : :
1638 : : /**
1639 : : * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1640 : : * @delta: pointer to a timespec64 delta value
1641 : : *
1642 : : * This hook is for architectures that cannot support read_persistent_clock64
1643 : : * because their RTC/persistent clock is only accessible when irqs are enabled.
1644 : : * and also don't have an effective nonstop clocksource.
1645 : : *
1646 : : * This function should only be called by rtc_resume(), and allows
1647 : : * a suspend offset to be injected into the timekeeping values.
1648 : : */
1649 : : void timekeeping_inject_sleeptime64(const struct timespec64 *delta)
1650 : : {
1651 : : struct timekeeper *tk = &tk_core.timekeeper;
1652 : : unsigned long flags;
1653 : :
1654 : : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1655 : : write_seqcount_begin(&tk_core.seq);
1656 : :
1657 : : suspend_timing_needed = false;
1658 : :
1659 : : timekeeping_forward_now(tk);
1660 : :
1661 : : __timekeeping_inject_sleeptime(tk, delta);
1662 : :
1663 : : timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1664 : :
1665 : : write_seqcount_end(&tk_core.seq);
1666 : : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1667 : :
1668 : : /* signal hrtimers about time change */
1669 : : clock_was_set();
1670 : : }
1671 : : #endif
1672 : :
1673 : : /**
1674 : : * timekeeping_resume - Resumes the generic timekeeping subsystem.
1675 : : */
1676 : 0 : void timekeeping_resume(void)
1677 : : {
1678 : : struct timekeeper *tk = &tk_core.timekeeper;
1679 : 0 : struct clocksource *clock = tk->tkr_mono.clock;
1680 : : unsigned long flags;
1681 : : struct timespec64 ts_new, ts_delta;
1682 : : u64 cycle_now, nsec;
1683 : : bool inject_sleeptime = false;
1684 : :
1685 : 0 : read_persistent_clock64(&ts_new);
1686 : :
1687 : 0 : clockevents_resume();
1688 : 0 : clocksource_resume();
1689 : :
1690 : 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1691 : : write_seqcount_begin(&tk_core.seq);
1692 : :
1693 : : /*
1694 : : * After system resumes, we need to calculate the suspended time and
1695 : : * compensate it for the OS time. There are 3 sources that could be
1696 : : * used: Nonstop clocksource during suspend, persistent clock and rtc
1697 : : * device.
1698 : : *
1699 : : * One specific platform may have 1 or 2 or all of them, and the
1700 : : * preference will be:
1701 : : * suspend-nonstop clocksource -> persistent clock -> rtc
1702 : : * The less preferred source will only be tried if there is no better
1703 : : * usable source. The rtc part is handled separately in rtc core code.
1704 : : */
1705 : : cycle_now = tk_clock_read(&tk->tkr_mono);
1706 : 0 : nsec = clocksource_stop_suspend_timing(clock, cycle_now);
1707 [ # # ]: 0 : if (nsec > 0) {
1708 : 0 : ts_delta = ns_to_timespec64(nsec);
1709 : : inject_sleeptime = true;
1710 [ # # ]: 0 : } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1711 : 0 : ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1712 : : inject_sleeptime = true;
1713 : : }
1714 : :
1715 [ # # ]: 0 : if (inject_sleeptime) {
1716 : 0 : suspend_timing_needed = false;
1717 : 0 : __timekeeping_inject_sleeptime(tk, &ts_delta);
1718 : : }
1719 : :
1720 : : /* Re-base the last cycle value */
1721 : 0 : tk->tkr_mono.cycle_last = cycle_now;
1722 : 0 : tk->tkr_raw.cycle_last = cycle_now;
1723 : :
1724 : 0 : tk->ntp_error = 0;
1725 : 0 : timekeeping_suspended = 0;
1726 : 0 : timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1727 : : write_seqcount_end(&tk_core.seq);
1728 : 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1729 : :
1730 : : touch_softlockup_watchdog();
1731 : :
1732 : 0 : tick_resume();
1733 : 0 : hrtimers_resume();
1734 : 0 : }
1735 : :
1736 : 0 : int timekeeping_suspend(void)
1737 : : {
1738 : : struct timekeeper *tk = &tk_core.timekeeper;
1739 : : unsigned long flags;
1740 : : struct timespec64 delta, delta_delta;
1741 : : static struct timespec64 old_delta;
1742 : : struct clocksource *curr_clock;
1743 : : u64 cycle_now;
1744 : :
1745 : 0 : read_persistent_clock64(&timekeeping_suspend_time);
1746 : :
1747 : : /*
1748 : : * On some systems the persistent_clock can not be detected at
1749 : : * timekeeping_init by its return value, so if we see a valid
1750 : : * value returned, update the persistent_clock_exists flag.
1751 : : */
1752 [ # # # # ]: 0 : if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1753 : 0 : persistent_clock_exists = true;
1754 : :
1755 : 0 : suspend_timing_needed = true;
1756 : :
1757 : 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1758 : : write_seqcount_begin(&tk_core.seq);
1759 : 0 : timekeeping_forward_now(tk);
1760 : 0 : timekeeping_suspended = 1;
1761 : :
1762 : : /*
1763 : : * Since we've called forward_now, cycle_last stores the value
1764 : : * just read from the current clocksource. Save this to potentially
1765 : : * use in suspend timing.
1766 : : */
1767 : 0 : curr_clock = tk->tkr_mono.clock;
1768 : 0 : cycle_now = tk->tkr_mono.cycle_last;
1769 : 0 : clocksource_start_suspend_timing(curr_clock, cycle_now);
1770 : :
1771 [ # # ]: 0 : if (persistent_clock_exists) {
1772 : : /*
1773 : : * To avoid drift caused by repeated suspend/resumes,
1774 : : * which each can add ~1 second drift error,
1775 : : * try to compensate so the difference in system time
1776 : : * and persistent_clock time stays close to constant.
1777 : : */
1778 : : delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1779 : : delta_delta = timespec64_sub(delta, old_delta);
1780 [ # # ]: 0 : if (abs(delta_delta.tv_sec) >= 2) {
1781 : : /*
1782 : : * if delta_delta is too large, assume time correction
1783 : : * has occurred and set old_delta to the current delta.
1784 : : */
1785 : 0 : old_delta = delta;
1786 : : } else {
1787 : : /* Otherwise try to adjust old_system to compensate */
1788 : 0 : timekeeping_suspend_time =
1789 : : timespec64_add(timekeeping_suspend_time, delta_delta);
1790 : : }
1791 : : }
1792 : :
1793 : 0 : timekeeping_update(tk, TK_MIRROR);
1794 : 0 : halt_fast_timekeeper(tk);
1795 : : write_seqcount_end(&tk_core.seq);
1796 : 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1797 : :
1798 : 0 : tick_suspend();
1799 : 0 : clocksource_suspend();
1800 : 0 : clockevents_suspend();
1801 : :
1802 : 0 : return 0;
1803 : : }
1804 : :
1805 : : /* sysfs resume/suspend bits for timekeeping */
1806 : : static struct syscore_ops timekeeping_syscore_ops = {
1807 : : .resume = timekeeping_resume,
1808 : : .suspend = timekeeping_suspend,
1809 : : };
1810 : :
1811 : 404 : static int __init timekeeping_init_ops(void)
1812 : : {
1813 : 404 : register_syscore_ops(&timekeeping_syscore_ops);
1814 : 404 : return 0;
1815 : : }
1816 : : device_initcall(timekeeping_init_ops);
1817 : :
1818 : : /*
1819 : : * Apply a multiplier adjustment to the timekeeper
1820 : : */
1821 : : static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1822 : : s64 offset,
1823 : : s32 mult_adj)
1824 : : {
1825 : 5007296 : s64 interval = tk->cycle_interval;
1826 : :
1827 [ + + ]: 5007296 : if (mult_adj == 0) {
1828 : : return;
1829 [ + + ]: 37650 : } else if (mult_adj == -1) {
1830 : 18390 : interval = -interval;
1831 : 18390 : offset = -offset;
1832 [ + + ]: 19260 : } else if (mult_adj != 1) {
1833 : 886 : interval *= mult_adj;
1834 : 886 : offset *= mult_adj;
1835 : : }
1836 : :
1837 : : /*
1838 : : * So the following can be confusing.
1839 : : *
1840 : : * To keep things simple, lets assume mult_adj == 1 for now.
1841 : : *
1842 : : * When mult_adj != 1, remember that the interval and offset values
1843 : : * have been appropriately scaled so the math is the same.
1844 : : *
1845 : : * The basic idea here is that we're increasing the multiplier
1846 : : * by one, this causes the xtime_interval to be incremented by
1847 : : * one cycle_interval. This is because:
1848 : : * xtime_interval = cycle_interval * mult
1849 : : * So if mult is being incremented by one:
1850 : : * xtime_interval = cycle_interval * (mult + 1)
1851 : : * Its the same as:
1852 : : * xtime_interval = (cycle_interval * mult) + cycle_interval
1853 : : * Which can be shortened to:
1854 : : * xtime_interval += cycle_interval
1855 : : *
1856 : : * So offset stores the non-accumulated cycles. Thus the current
1857 : : * time (in shifted nanoseconds) is:
1858 : : * now = (offset * adj) + xtime_nsec
1859 : : * Now, even though we're adjusting the clock frequency, we have
1860 : : * to keep time consistent. In other words, we can't jump back
1861 : : * in time, and we also want to avoid jumping forward in time.
1862 : : *
1863 : : * So given the same offset value, we need the time to be the same
1864 : : * both before and after the freq adjustment.
1865 : : * now = (offset * adj_1) + xtime_nsec_1
1866 : : * now = (offset * adj_2) + xtime_nsec_2
1867 : : * So:
1868 : : * (offset * adj_1) + xtime_nsec_1 =
1869 : : * (offset * adj_2) + xtime_nsec_2
1870 : : * And we know:
1871 : : * adj_2 = adj_1 + 1
1872 : : * So:
1873 : : * (offset * adj_1) + xtime_nsec_1 =
1874 : : * (offset * (adj_1+1)) + xtime_nsec_2
1875 : : * (offset * adj_1) + xtime_nsec_1 =
1876 : : * (offset * adj_1) + offset + xtime_nsec_2
1877 : : * Canceling the sides:
1878 : : * xtime_nsec_1 = offset + xtime_nsec_2
1879 : : * Which gives us:
1880 : : * xtime_nsec_2 = xtime_nsec_1 - offset
1881 : : * Which simplfies to:
1882 : : * xtime_nsec -= offset
1883 : : */
1884 [ + + - + ]: 37650 : if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1885 : : /* NTP adjustment caused clocksource mult overflow */
1886 [ # # ]: 0 : WARN_ON_ONCE(1);
1887 : : return;
1888 : : }
1889 : :
1890 : 37650 : tk->tkr_mono.mult += mult_adj;
1891 : 37650 : tk->xtime_interval += interval;
1892 : 37650 : tk->tkr_mono.xtime_nsec -= offset;
1893 : : }
1894 : :
1895 : : /*
1896 : : * Adjust the timekeeper's multiplier to the correct frequency
1897 : : * and also to reduce the accumulated error value.
1898 : : */
1899 : 5007296 : static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1900 : : {
1901 : : u32 mult;
1902 : :
1903 : : /*
1904 : : * Determine the multiplier from the current NTP tick length.
1905 : : * Avoid expensive division when the tick length doesn't change.
1906 : : */
1907 [ + + ]: 5007296 : if (likely(tk->ntp_tick == ntp_tick_length())) {
1908 : 5006410 : mult = tk->tkr_mono.mult - tk->ntp_err_mult;
1909 : : } else {
1910 : 886 : tk->ntp_tick = ntp_tick_length();
1911 : 1772 : mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
1912 : 886 : tk->xtime_remainder, tk->cycle_interval);
1913 : : }
1914 : :
1915 : : /*
1916 : : * If the clock is behind the NTP time, increase the multiplier by 1
1917 : : * to catch up with it. If it's ahead and there was a remainder in the
1918 : : * tick division, the clock will slow down. Otherwise it will stay
1919 : : * ahead until the tick length changes to a non-divisible value.
1920 : : */
1921 : 5007296 : tk->ntp_err_mult = tk->ntp_error > 0 ? 1 : 0;
1922 : 5007296 : mult += tk->ntp_err_mult;
1923 : :
1924 : 5007296 : timekeeping_apply_adjustment(tk, offset, mult - tk->tkr_mono.mult);
1925 : :
1926 [ + + - + ]: 5007296 : if (unlikely(tk->tkr_mono.clock->maxadj &&
1927 : : (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1928 : : > tk->tkr_mono.clock->maxadj))) {
1929 [ # # ]: 0 : printk_once(KERN_WARNING
1930 : : "Adjusting %s more than 11%% (%ld vs %ld)\n",
1931 : : tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1932 : : (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1933 : : }
1934 : :
1935 : : /*
1936 : : * It may be possible that when we entered this function, xtime_nsec
1937 : : * was very small. Further, if we're slightly speeding the clocksource
1938 : : * in the code above, its possible the required corrective factor to
1939 : : * xtime_nsec could cause it to underflow.
1940 : : *
1941 : : * Now, since we have already accumulated the second and the NTP
1942 : : * subsystem has been notified via second_overflow(), we need to skip
1943 : : * the next update.
1944 : : */
1945 [ - + ]: 5007296 : if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1946 : 0 : tk->tkr_mono.xtime_nsec += (u64)NSEC_PER_SEC <<
1947 : 0 : tk->tkr_mono.shift;
1948 : 0 : tk->xtime_sec--;
1949 : 0 : tk->skip_second_overflow = 1;
1950 : : }
1951 : 5007296 : }
1952 : :
1953 : : /**
1954 : : * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1955 : : *
1956 : : * Helper function that accumulates the nsecs greater than a second
1957 : : * from the xtime_nsec field to the xtime_secs field.
1958 : : * It also calls into the NTP code to handle leapsecond processing.
1959 : : *
1960 : : */
1961 : 10063654 : static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1962 : : {
1963 : 10063654 : u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1964 : : unsigned int clock_set = 0;
1965 : :
1966 [ + + ]: 20181526 : while (tk->tkr_mono.xtime_nsec >= nsecps) {
1967 : : int leap;
1968 : :
1969 : 54218 : tk->tkr_mono.xtime_nsec -= nsecps;
1970 : 54218 : tk->xtime_sec++;
1971 : :
1972 : : /*
1973 : : * Skip NTP update if this second was accumulated before,
1974 : : * i.e. xtime_nsec underflowed in timekeeping_adjust()
1975 : : */
1976 [ - + ]: 54218 : if (unlikely(tk->skip_second_overflow)) {
1977 : 0 : tk->skip_second_overflow = 0;
1978 : 0 : continue;
1979 : : }
1980 : :
1981 : : /* Figure out if its a leap sec and apply if needed */
1982 : 54218 : leap = second_overflow(tk->xtime_sec);
1983 [ - + ]: 54218 : if (unlikely(leap)) {
1984 : : struct timespec64 ts;
1985 : :
1986 : 0 : tk->xtime_sec += leap;
1987 : :
1988 : 0 : ts.tv_sec = leap;
1989 : : ts.tv_nsec = 0;
1990 : 0 : tk_set_wall_to_mono(tk,
1991 : : timespec64_sub(tk->wall_to_monotonic, ts));
1992 : :
1993 : 0 : __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1994 : :
1995 : : clock_set = TK_CLOCK_WAS_SET;
1996 : : }
1997 : : }
1998 : 10063654 : return clock_set;
1999 : : }
2000 : :
2001 : : /**
2002 : : * logarithmic_accumulation - shifted accumulation of cycles
2003 : : *
2004 : : * This functions accumulates a shifted interval of cycles into
2005 : : * into a shifted interval nanoseconds. Allows for O(log) accumulation
2006 : : * loop.
2007 : : *
2008 : : * Returns the unconsumed cycles.
2009 : : */
2010 : 6528976 : static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
2011 : : u32 shift, unsigned int *clock_set)
2012 : : {
2013 : 6528976 : u64 interval = tk->cycle_interval << shift;
2014 : : u64 snsec_per_sec;
2015 : :
2016 : : /* If the offset is smaller than a shifted interval, do nothing */
2017 [ + + ]: 6528976 : if (offset < interval)
2018 : : return offset;
2019 : :
2020 : : /* Accumulate one shifted interval */
2021 : 5056360 : offset -= interval;
2022 : 5056360 : tk->tkr_mono.cycle_last += interval;
2023 : 5056360 : tk->tkr_raw.cycle_last += interval;
2024 : :
2025 : 5056360 : tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2026 : 5056360 : *clock_set |= accumulate_nsecs_to_secs(tk);
2027 : :
2028 : : /* Accumulate raw time */
2029 : 5056360 : tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2030 : 5056360 : snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2031 [ + + ]: 10167338 : while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2032 : 54618 : tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2033 : 54618 : tk->raw_sec++;
2034 : : }
2035 : :
2036 : : /* Accumulate error between NTP and clock interval */
2037 : 5056360 : tk->ntp_error += tk->ntp_tick << shift;
2038 : 10112720 : tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2039 : 5056360 : (tk->ntp_error_shift + shift);
2040 : :
2041 : 5056360 : return offset;
2042 : : }
2043 : :
2044 : : /*
2045 : : * timekeeping_advance - Updates the timekeeper to the current time and
2046 : : * current NTP tick length
2047 : : */
2048 : 5159318 : static void timekeeping_advance(enum timekeeping_adv_mode mode)
2049 : : {
2050 : : struct timekeeper *real_tk = &tk_core.timekeeper;
2051 : : struct timekeeper *tk = &shadow_timekeeper;
2052 : : u64 offset;
2053 : : int shift = 0, maxshift;
2054 : 5159318 : unsigned int clock_set = 0;
2055 : : unsigned long flags;
2056 : :
2057 : 5159318 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
2058 : :
2059 : : /* Make sure we're fully resumed: */
2060 [ + - ]: 5159318 : if (unlikely(timekeeping_suspended))
2061 : : goto out;
2062 : :
2063 : : #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2064 : : offset = real_tk->cycle_interval;
2065 : :
2066 : : if (mode != TK_ADV_TICK)
2067 : : goto out;
2068 : : #else
2069 : 5159318 : offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2070 : : tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2071 : :
2072 : : /* Check if there's really nothing to do */
2073 [ + + - + ]: 5159318 : if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK)
2074 : : goto out;
2075 : : #endif
2076 : :
2077 : : /* Do some additional sanity checking */
2078 : : timekeeping_check_update(tk, offset);
2079 : :
2080 : : /*
2081 : : * With NO_HZ we may have to accumulate many cycle_intervals
2082 : : * (think "ticks") worth of time at once. To do this efficiently,
2083 : : * we calculate the largest doubling multiple of cycle_intervals
2084 : : * that is smaller than the offset. We then accumulate that
2085 : : * chunk in one go, and then try to consume the next smaller
2086 : : * doubled multiple.
2087 : : */
2088 [ - + # # : 15021882 : shift = ilog2(offset) - ilog2(tk->cycle_interval);
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# - + # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# ]
2089 : 5007294 : shift = max(0, shift);
2090 : : /* Bound shift to one less than what overflows tick_length */
2091 : 10014588 : maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2092 : 5007294 : shift = min(shift, maxshift);
2093 [ + + ]: 16543564 : while (offset >= tk->cycle_interval) {
2094 : 6528976 : offset = logarithmic_accumulation(tk, offset, shift,
2095 : : &clock_set);
2096 [ + - ]: 6528976 : if (offset < tk->cycle_interval<<shift)
2097 : 6528976 : shift--;
2098 : : }
2099 : :
2100 : : /* Adjust the multiplier to correct NTP error */
2101 : 5007294 : timekeeping_adjust(tk, offset);
2102 : :
2103 : : /*
2104 : : * Finally, make sure that after the rounding
2105 : : * xtime_nsec isn't larger than NSEC_PER_SEC
2106 : : */
2107 : 5007294 : clock_set |= accumulate_nsecs_to_secs(tk);
2108 : :
2109 : : write_seqcount_begin(&tk_core.seq);
2110 : : /*
2111 : : * Update the real timekeeper.
2112 : : *
2113 : : * We could avoid this memcpy by switching pointers, but that
2114 : : * requires changes to all other timekeeper usage sites as
2115 : : * well, i.e. move the timekeeper pointer getter into the
2116 : : * spinlocked/seqcount protected sections. And we trade this
2117 : : * memcpy under the tk_core.seq against one before we start
2118 : : * updating.
2119 : : */
2120 : 5007294 : timekeeping_update(tk, clock_set);
2121 : 5007294 : memcpy(real_tk, tk, sizeof(*tk));
2122 : : /* The memcpy must come last. Do not put anything here! */
2123 : : write_seqcount_end(&tk_core.seq);
2124 : : out:
2125 : 5159318 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2126 [ - + ]: 5159318 : if (clock_set)
2127 : : /* Have to call _delayed version, since in irq context*/
2128 : 0 : clock_was_set_delayed();
2129 : 5159318 : }
2130 : :
2131 : : /**
2132 : : * update_wall_time - Uses the current clocksource to increment the wall time
2133 : : *
2134 : : */
2135 : 5159316 : void update_wall_time(void)
2136 : : {
2137 : 5159316 : timekeeping_advance(TK_ADV_TICK);
2138 : 5159316 : }
2139 : :
2140 : : /**
2141 : : * getboottime64 - Return the real time of system boot.
2142 : : * @ts: pointer to the timespec64 to be set
2143 : : *
2144 : : * Returns the wall-time of boot in a timespec64.
2145 : : *
2146 : : * This is based on the wall_to_monotonic offset and the total suspend
2147 : : * time. Calls to settimeofday will affect the value returned (which
2148 : : * basically means that however wrong your real time clock is at boot time,
2149 : : * you get the right time here).
2150 : : */
2151 : 8356 : void getboottime64(struct timespec64 *ts)
2152 : : {
2153 : : struct timekeeper *tk = &tk_core.timekeeper;
2154 : 8356 : ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2155 : :
2156 : 8356 : *ts = ktime_to_timespec64(t);
2157 : 8356 : }
2158 : : EXPORT_SYMBOL_GPL(getboottime64);
2159 : :
2160 : 21850694 : void ktime_get_coarse_real_ts64(struct timespec64 *ts)
2161 : : {
2162 : : struct timekeeper *tk = &tk_core.timekeeper;
2163 : : unsigned int seq;
2164 : :
2165 : : do {
2166 : : seq = read_seqcount_begin(&tk_core.seq);
2167 : :
2168 : 21849348 : *ts = tk_xtime(tk);
2169 [ + + ]: 21851130 : } while (read_seqcount_retry(&tk_core.seq, seq));
2170 : 21850564 : }
2171 : : EXPORT_SYMBOL(ktime_get_coarse_real_ts64);
2172 : :
2173 : 0 : void ktime_get_coarse_ts64(struct timespec64 *ts)
2174 : : {
2175 : : struct timekeeper *tk = &tk_core.timekeeper;
2176 : : struct timespec64 now, mono;
2177 : : unsigned int seq;
2178 : :
2179 : : do {
2180 : : seq = read_seqcount_begin(&tk_core.seq);
2181 : :
2182 : : now = tk_xtime(tk);
2183 : 0 : mono = tk->wall_to_monotonic;
2184 [ # # ]: 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
2185 : :
2186 : 0 : set_normalized_timespec64(ts, now.tv_sec + mono.tv_sec,
2187 : 0 : now.tv_nsec + mono.tv_nsec);
2188 : 0 : }
2189 : : EXPORT_SYMBOL(ktime_get_coarse_ts64);
2190 : :
2191 : : /*
2192 : : * Must hold jiffies_lock
2193 : : */
2194 : 5159310 : void do_timer(unsigned long ticks)
2195 : : {
2196 : 5159310 : jiffies_64 += ticks;
2197 : 5159310 : calc_global_load(ticks);
2198 : 5159310 : }
2199 : :
2200 : : /**
2201 : : * ktime_get_update_offsets_now - hrtimer helper
2202 : : * @cwsseq: pointer to check and store the clock was set sequence number
2203 : : * @offs_real: pointer to storage for monotonic -> realtime offset
2204 : : * @offs_boot: pointer to storage for monotonic -> boottime offset
2205 : : * @offs_tai: pointer to storage for monotonic -> clock tai offset
2206 : : *
2207 : : * Returns current monotonic time and updates the offsets if the
2208 : : * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2209 : : * different.
2210 : : *
2211 : : * Called from hrtimer_interrupt() or retrigger_next_event()
2212 : : */
2213 : 17240650 : ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2214 : : ktime_t *offs_boot, ktime_t *offs_tai)
2215 : : {
2216 : : struct timekeeper *tk = &tk_core.timekeeper;
2217 : : unsigned int seq;
2218 : : ktime_t base;
2219 : : u64 nsecs;
2220 : :
2221 : : do {
2222 : : seq = read_seqcount_begin(&tk_core.seq);
2223 : :
2224 : 17299590 : base = tk->tkr_mono.base;
2225 : 17299590 : nsecs = timekeeping_get_ns(&tk->tkr_mono);
2226 : 17391886 : base = ktime_add_ns(base, nsecs);
2227 : :
2228 [ + + ]: 17391886 : if (*cwsseq != tk->clock_was_set_seq) {
2229 : 8054 : *cwsseq = tk->clock_was_set_seq;
2230 : 8054 : *offs_real = tk->offs_real;
2231 : 8054 : *offs_boot = tk->offs_boot;
2232 : 8054 : *offs_tai = tk->offs_tai;
2233 : : }
2234 : :
2235 : : /* Handle leapsecond insertion adjustments */
2236 [ - + ]: 17391886 : if (unlikely(base >= tk->next_leap_ktime))
2237 : 0 : *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2238 : :
2239 [ + + ]: 17409458 : } while (read_seqcount_retry(&tk_core.seq, seq));
2240 : :
2241 : 17237136 : return base;
2242 : : }
2243 : :
2244 : : /**
2245 : : * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
2246 : : */
2247 : 504 : static int timekeeping_validate_timex(const struct __kernel_timex *txc)
2248 : : {
2249 [ - + ]: 504 : if (txc->modes & ADJ_ADJTIME) {
2250 : : /* singleshot must not be used with any other mode bits */
2251 [ # # ]: 0 : if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
2252 : : return -EINVAL;
2253 [ # # # # ]: 0 : if (!(txc->modes & ADJ_OFFSET_READONLY) &&
2254 : 0 : !capable(CAP_SYS_TIME))
2255 : : return -EPERM;
2256 : : } else {
2257 : : /* In order to modify anything, you gotta be super-user! */
2258 [ + - + - ]: 504 : if (txc->modes && !capable(CAP_SYS_TIME))
2259 : : return -EPERM;
2260 : : /*
2261 : : * if the quartz is off by more than 10% then
2262 : : * something is VERY wrong!
2263 : : */
2264 [ - + # # ]: 504 : if (txc->modes & ADJ_TICK &&
2265 : 0 : (txc->tick < 900000/USER_HZ ||
2266 : : txc->tick > 1100000/USER_HZ))
2267 : : return -EINVAL;
2268 : : }
2269 : :
2270 [ + + ]: 504 : if (txc->modes & ADJ_SETOFFSET) {
2271 : : /* In order to inject time, you gotta be super-user! */
2272 [ + - ]: 404 : if (!capable(CAP_SYS_TIME))
2273 : : return -EPERM;
2274 : :
2275 : : /*
2276 : : * Validate if a timespec/timeval used to inject a time
2277 : : * offset is valid. Offsets can be postive or negative, so
2278 : : * we don't check tv_sec. The value of the timeval/timespec
2279 : : * is the sum of its fields,but *NOTE*:
2280 : : * The field tv_usec/tv_nsec must always be non-negative and
2281 : : * we can't have more nanoseconds/microseconds than a second.
2282 : : */
2283 [ + - ]: 404 : if (txc->time.tv_usec < 0)
2284 : : return -EINVAL;
2285 : :
2286 [ + - ]: 404 : if (txc->modes & ADJ_NANO) {
2287 [ + - ]: 404 : if (txc->time.tv_usec >= NSEC_PER_SEC)
2288 : : return -EINVAL;
2289 : : } else {
2290 [ # # ]: 0 : if (txc->time.tv_usec >= USEC_PER_SEC)
2291 : : return -EINVAL;
2292 : : }
2293 : : }
2294 : :
2295 : : /*
2296 : : * Check for potential multiplication overflows that can
2297 : : * only happen on 64-bit systems:
2298 : : */
2299 : : if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
2300 : : if (LLONG_MIN / PPM_SCALE > txc->freq)
2301 : : return -EINVAL;
2302 : : if (LLONG_MAX / PPM_SCALE < txc->freq)
2303 : : return -EINVAL;
2304 : : }
2305 : :
2306 : : return 0;
2307 : : }
2308 : :
2309 : :
2310 : : /**
2311 : : * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2312 : : */
2313 : 504 : int do_adjtimex(struct __kernel_timex *txc)
2314 : : {
2315 : : struct timekeeper *tk = &tk_core.timekeeper;
2316 : : struct audit_ntp_data ad;
2317 : : unsigned long flags;
2318 : : struct timespec64 ts;
2319 : : s32 orig_tai, tai;
2320 : : int ret;
2321 : :
2322 : : /* Validate the data before disabling interrupts */
2323 : 504 : ret = timekeeping_validate_timex(txc);
2324 [ + - ]: 504 : if (ret)
2325 : : return ret;
2326 : :
2327 [ + + ]: 504 : if (txc->modes & ADJ_SETOFFSET) {
2328 : : struct timespec64 delta;
2329 : 404 : delta.tv_sec = txc->time.tv_sec;
2330 : 404 : delta.tv_nsec = txc->time.tv_usec;
2331 [ - + ]: 404 : if (!(txc->modes & ADJ_NANO))
2332 : 0 : delta.tv_nsec *= 1000;
2333 : 404 : ret = timekeeping_inject_offset(&delta);
2334 [ - + ]: 404 : if (ret)
2335 : 0 : return ret;
2336 : :
2337 : 404 : audit_tk_injoffset(delta);
2338 : : }
2339 : :
2340 : : audit_ntp_init(&ad);
2341 : :
2342 : 504 : ktime_get_real_ts64(&ts);
2343 : :
2344 : 504 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
2345 : : write_seqcount_begin(&tk_core.seq);
2346 : :
2347 : 504 : orig_tai = tai = tk->tai_offset;
2348 : 504 : ret = __do_adjtimex(txc, &ts, &tai, &ad);
2349 : :
2350 [ - + ]: 504 : if (tai != orig_tai) {
2351 : : __timekeeping_set_tai_offset(tk, tai);
2352 : 0 : timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2353 : : }
2354 : 504 : tk_update_leap_state(tk);
2355 : :
2356 : : write_seqcount_end(&tk_core.seq);
2357 : 504 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2358 : :
2359 : 504 : audit_ntp_log(&ad);
2360 : :
2361 : : /* Update the multiplier immediately if frequency was set directly */
2362 [ - + ]: 504 : if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK))
2363 : 0 : timekeeping_advance(TK_ADV_FREQ);
2364 : :
2365 [ - + ]: 504 : if (tai != orig_tai)
2366 : 0 : clock_was_set();
2367 : :
2368 : 504 : ntp_notify_cmos_timer();
2369 : :
2370 : 504 : return ret;
2371 : : }
2372 : :
2373 : : #ifdef CONFIG_NTP_PPS
2374 : : /**
2375 : : * hardpps() - Accessor function to NTP __hardpps function
2376 : : */
2377 : : void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2378 : : {
2379 : : unsigned long flags;
2380 : :
2381 : : raw_spin_lock_irqsave(&timekeeper_lock, flags);
2382 : : write_seqcount_begin(&tk_core.seq);
2383 : :
2384 : : __hardpps(phase_ts, raw_ts);
2385 : :
2386 : : write_seqcount_end(&tk_core.seq);
2387 : : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2388 : : }
2389 : : EXPORT_SYMBOL(hardpps);
2390 : : #endif /* CONFIG_NTP_PPS */
2391 : :
2392 : : /**
2393 : : * xtime_update() - advances the timekeeping infrastructure
2394 : : * @ticks: number of ticks, that have elapsed since the last call.
2395 : : *
2396 : : * Must be called with interrupts disabled.
2397 : : */
2398 : 0 : void xtime_update(unsigned long ticks)
2399 : : {
2400 : : write_seqlock(&jiffies_lock);
2401 : : do_timer(ticks);
2402 : : write_sequnlock(&jiffies_lock);
2403 : : update_wall_time();
2404 : 0 : }
|
