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/timekeeper_internal.h> 12 #include <linux/module.h> 13 #include <linux/interrupt.h> 14 #include <linux/percpu.h> 15 #include <linux/init.h> 16 #include <linux/mm.h> 17 #include <linux/sched.h> 18 #include <linux/syscore_ops.h> 19 #include <linux/clocksource.h> 20 #include <linux/jiffies.h> 21 #include <linux/time.h> 22 #include <linux/tick.h> 23 #include <linux/stop_machine.h> 24 #include <linux/pvclock_gtod.h> 25 #include <linux/compiler.h> 26 27 #include "tick-internal.h" 28 #include "ntp_internal.h" 29 #include "timekeeping_internal.h" 30 31 #define TK_CLEAR_NTP (1 << 0) 32 #define TK_MIRROR (1 << 1) 33 #define TK_CLOCK_WAS_SET (1 << 2) 34 35 /* 36 * The most important data for readout fits into a single 64 byte 37 * cache line. 38 */ 39 static struct { 40 seqcount_t seq; 41 struct timekeeper timekeeper; 42 } tk_core ____cacheline_aligned; 43 44 static DEFINE_RAW_SPINLOCK(timekeeper_lock); 45 static struct timekeeper shadow_timekeeper; 46 47 /** 48 * struct tk_fast - NMI safe timekeeper 49 * @seq: Sequence counter for protecting updates. The lowest bit 50 * is the index for the tk_read_base array 51 * @base: tk_read_base array. Access is indexed by the lowest bit of 52 * @seq. 53 * 54 * See @update_fast_timekeeper() below. 55 */ 56 struct tk_fast { 57 seqcount_t seq; 58 struct tk_read_base base[2]; 59 }; 60 61 static struct tk_fast tk_fast_mono ____cacheline_aligned; 62 63 /* flag for if timekeeping is suspended */ 64 int __read_mostly timekeeping_suspended; 65 66 /* Flag for if there is a persistent clock on this platform */ 67 bool __read_mostly persistent_clock_exist = false; 68 69 static inline void tk_normalize_xtime(struct timekeeper *tk) 70 { 71 while (tk->tkr.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr.shift)) { 72 tk->tkr.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr.shift; 73 tk->xtime_sec++; 74 } 75 } 76 77 static inline struct timespec64 tk_xtime(struct timekeeper *tk) 78 { 79 struct timespec64 ts; 80 81 ts.tv_sec = tk->xtime_sec; 82 ts.tv_nsec = (long)(tk->tkr.xtime_nsec >> tk->tkr.shift); 83 return ts; 84 } 85 86 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts) 87 { 88 tk->xtime_sec = ts->tv_sec; 89 tk->tkr.xtime_nsec = (u64)ts->tv_nsec << tk->tkr.shift; 90 } 91 92 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts) 93 { 94 tk->xtime_sec += ts->tv_sec; 95 tk->tkr.xtime_nsec += (u64)ts->tv_nsec << tk->tkr.shift; 96 tk_normalize_xtime(tk); 97 } 98 99 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm) 100 { 101 struct timespec64 tmp; 102 103 /* 104 * Verify consistency of: offset_real = -wall_to_monotonic 105 * before modifying anything 106 */ 107 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec, 108 -tk->wall_to_monotonic.tv_nsec); 109 WARN_ON_ONCE(tk->offs_real.tv64 != timespec64_to_ktime(tmp).tv64); 110 tk->wall_to_monotonic = wtm; 111 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec); 112 tk->offs_real = timespec64_to_ktime(tmp); 113 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0)); 114 } 115 116 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta) 117 { 118 tk->offs_boot = ktime_add(tk->offs_boot, delta); 119 } 120 121 /** 122 * tk_setup_internals - Set up internals to use clocksource clock. 123 * 124 * @tk: The target timekeeper to setup. 125 * @clock: Pointer to clocksource. 126 * 127 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment 128 * pair and interval request. 129 * 130 * Unless you're the timekeeping code, you should not be using this! 131 */ 132 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock) 133 { 134 cycle_t interval; 135 u64 tmp, ntpinterval; 136 struct clocksource *old_clock; 137 138 old_clock = tk->tkr.clock; 139 tk->tkr.clock = clock; 140 tk->tkr.read = clock->read; 141 tk->tkr.mask = clock->mask; 142 tk->tkr.cycle_last = tk->tkr.read(clock); 143 144 /* Do the ns -> cycle conversion first, using original mult */ 145 tmp = NTP_INTERVAL_LENGTH; 146 tmp <<= clock->shift; 147 ntpinterval = tmp; 148 tmp += clock->mult/2; 149 do_div(tmp, clock->mult); 150 if (tmp == 0) 151 tmp = 1; 152 153 interval = (cycle_t) tmp; 154 tk->cycle_interval = interval; 155 156 /* Go back from cycles -> shifted ns */ 157 tk->xtime_interval = (u64) interval * clock->mult; 158 tk->xtime_remainder = ntpinterval - tk->xtime_interval; 159 tk->raw_interval = 160 ((u64) interval * clock->mult) >> clock->shift; 161 162 /* if changing clocks, convert xtime_nsec shift units */ 163 if (old_clock) { 164 int shift_change = clock->shift - old_clock->shift; 165 if (shift_change < 0) 166 tk->tkr.xtime_nsec >>= -shift_change; 167 else 168 tk->tkr.xtime_nsec <<= shift_change; 169 } 170 tk->tkr.shift = clock->shift; 171 172 tk->ntp_error = 0; 173 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; 174 tk->ntp_tick = ntpinterval << tk->ntp_error_shift; 175 176 /* 177 * The timekeeper keeps its own mult values for the currently 178 * active clocksource. These value will be adjusted via NTP 179 * to counteract clock drifting. 180 */ 181 tk->tkr.mult = clock->mult; 182 tk->ntp_err_mult = 0; 183 } 184 185 /* Timekeeper helper functions. */ 186 187 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET 188 static u32 default_arch_gettimeoffset(void) { return 0; } 189 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset; 190 #else 191 static inline u32 arch_gettimeoffset(void) { return 0; } 192 #endif 193 194 static inline s64 timekeeping_get_ns(struct tk_read_base *tkr) 195 { 196 cycle_t cycle_now, delta; 197 s64 nsec; 198 199 /* read clocksource: */ 200 cycle_now = tkr->read(tkr->clock); 201 202 /* calculate the delta since the last update_wall_time: */ 203 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask); 204 205 nsec = delta * tkr->mult + tkr->xtime_nsec; 206 nsec >>= tkr->shift; 207 208 /* If arch requires, add in get_arch_timeoffset() */ 209 return nsec + arch_gettimeoffset(); 210 } 211 212 static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk) 213 { 214 struct clocksource *clock = tk->tkr.clock; 215 cycle_t cycle_now, delta; 216 s64 nsec; 217 218 /* read clocksource: */ 219 cycle_now = tk->tkr.read(clock); 220 221 /* calculate the delta since the last update_wall_time: */ 222 delta = clocksource_delta(cycle_now, tk->tkr.cycle_last, tk->tkr.mask); 223 224 /* convert delta to nanoseconds. */ 225 nsec = clocksource_cyc2ns(delta, clock->mult, clock->shift); 226 227 /* If arch requires, add in get_arch_timeoffset() */ 228 return nsec + arch_gettimeoffset(); 229 } 230 231 /** 232 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper. 233 * @tk: The timekeeper from which we take the update 234 * @tkf: The fast timekeeper to update 235 * @tbase: The time base for the fast timekeeper (mono/raw) 236 * 237 * We want to use this from any context including NMI and tracing / 238 * instrumenting the timekeeping code itself. 239 * 240 * So we handle this differently than the other timekeeping accessor 241 * functions which retry when the sequence count has changed. The 242 * update side does: 243 * 244 * smp_wmb(); <- Ensure that the last base[1] update is visible 245 * tkf->seq++; 246 * smp_wmb(); <- Ensure that the seqcount update is visible 247 * update(tkf->base[0], tk); 248 * smp_wmb(); <- Ensure that the base[0] update is visible 249 * tkf->seq++; 250 * smp_wmb(); <- Ensure that the seqcount update is visible 251 * update(tkf->base[1], tk); 252 * 253 * The reader side does: 254 * 255 * do { 256 * seq = tkf->seq; 257 * smp_rmb(); 258 * idx = seq & 0x01; 259 * now = now(tkf->base[idx]); 260 * smp_rmb(); 261 * } while (seq != tkf->seq) 262 * 263 * As long as we update base[0] readers are forced off to 264 * base[1]. Once base[0] is updated readers are redirected to base[0] 265 * and the base[1] update takes place. 266 * 267 * So if a NMI hits the update of base[0] then it will use base[1] 268 * which is still consistent. In the worst case this can result is a 269 * slightly wrong timestamp (a few nanoseconds). See 270 * @ktime_get_mono_fast_ns. 271 */ 272 static void update_fast_timekeeper(struct timekeeper *tk) 273 { 274 struct tk_read_base *base = tk_fast_mono.base; 275 276 /* Force readers off to base[1] */ 277 raw_write_seqcount_latch(&tk_fast_mono.seq); 278 279 /* Update base[0] */ 280 memcpy(base, &tk->tkr, sizeof(*base)); 281 282 /* Force readers back to base[0] */ 283 raw_write_seqcount_latch(&tk_fast_mono.seq); 284 285 /* Update base[1] */ 286 memcpy(base + 1, base, sizeof(*base)); 287 } 288 289 /** 290 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic 291 * 292 * This timestamp is not guaranteed to be monotonic across an update. 293 * The timestamp is calculated by: 294 * 295 * now = base_mono + clock_delta * slope 296 * 297 * So if the update lowers the slope, readers who are forced to the 298 * not yet updated second array are still using the old steeper slope. 299 * 300 * tmono 301 * ^ 302 * | o n 303 * | o n 304 * | u 305 * | o 306 * |o 307 * |12345678---> reader order 308 * 309 * o = old slope 310 * u = update 311 * n = new slope 312 * 313 * So reader 6 will observe time going backwards versus reader 5. 314 * 315 * While other CPUs are likely to be able observe that, the only way 316 * for a CPU local observation is when an NMI hits in the middle of 317 * the update. Timestamps taken from that NMI context might be ahead 318 * of the following timestamps. Callers need to be aware of that and 319 * deal with it. 320 */ 321 u64 notrace ktime_get_mono_fast_ns(void) 322 { 323 struct tk_read_base *tkr; 324 unsigned int seq; 325 u64 now; 326 327 do { 328 seq = raw_read_seqcount(&tk_fast_mono.seq); 329 tkr = tk_fast_mono.base + (seq & 0x01); 330 now = ktime_to_ns(tkr->base_mono) + timekeeping_get_ns(tkr); 331 332 } while (read_seqcount_retry(&tk_fast_mono.seq, seq)); 333 return now; 334 } 335 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns); 336 337 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD 338 339 static inline void update_vsyscall(struct timekeeper *tk) 340 { 341 struct timespec xt, wm; 342 343 xt = timespec64_to_timespec(tk_xtime(tk)); 344 wm = timespec64_to_timespec(tk->wall_to_monotonic); 345 update_vsyscall_old(&xt, &wm, tk->tkr.clock, tk->tkr.mult, 346 tk->tkr.cycle_last); 347 } 348 349 static inline void old_vsyscall_fixup(struct timekeeper *tk) 350 { 351 s64 remainder; 352 353 /* 354 * Store only full nanoseconds into xtime_nsec after rounding 355 * it up and add the remainder to the error difference. 356 * XXX - This is necessary to avoid small 1ns inconsistnecies caused 357 * by truncating the remainder in vsyscalls. However, it causes 358 * additional work to be done in timekeeping_adjust(). Once 359 * the vsyscall implementations are converted to use xtime_nsec 360 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD 361 * users are removed, this can be killed. 362 */ 363 remainder = tk->tkr.xtime_nsec & ((1ULL << tk->tkr.shift) - 1); 364 tk->tkr.xtime_nsec -= remainder; 365 tk->tkr.xtime_nsec += 1ULL << tk->tkr.shift; 366 tk->ntp_error += remainder << tk->ntp_error_shift; 367 tk->ntp_error -= (1ULL << tk->tkr.shift) << tk->ntp_error_shift; 368 } 369 #else 370 #define old_vsyscall_fixup(tk) 371 #endif 372 373 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain); 374 375 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set) 376 { 377 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk); 378 } 379 380 /** 381 * pvclock_gtod_register_notifier - register a pvclock timedata update listener 382 */ 383 int pvclock_gtod_register_notifier(struct notifier_block *nb) 384 { 385 struct timekeeper *tk = &tk_core.timekeeper; 386 unsigned long flags; 387 int ret; 388 389 raw_spin_lock_irqsave(&timekeeper_lock, flags); 390 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb); 391 update_pvclock_gtod(tk, true); 392 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 393 394 return ret; 395 } 396 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier); 397 398 /** 399 * pvclock_gtod_unregister_notifier - unregister a pvclock 400 * timedata update listener 401 */ 402 int pvclock_gtod_unregister_notifier(struct notifier_block *nb) 403 { 404 unsigned long flags; 405 int ret; 406 407 raw_spin_lock_irqsave(&timekeeper_lock, flags); 408 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb); 409 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 410 411 return ret; 412 } 413 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier); 414 415 /* 416 * Update the ktime_t based scalar nsec members of the timekeeper 417 */ 418 static inline void tk_update_ktime_data(struct timekeeper *tk) 419 { 420 s64 nsec; 421 422 /* 423 * The xtime based monotonic readout is: 424 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now(); 425 * The ktime based monotonic readout is: 426 * nsec = base_mono + now(); 427 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec 428 */ 429 nsec = (s64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec); 430 nsec *= NSEC_PER_SEC; 431 nsec += tk->wall_to_monotonic.tv_nsec; 432 tk->tkr.base_mono = ns_to_ktime(nsec); 433 434 /* Update the monotonic raw base */ 435 tk->base_raw = timespec64_to_ktime(tk->raw_time); 436 } 437 438 /* must hold timekeeper_lock */ 439 static void timekeeping_update(struct timekeeper *tk, unsigned int action) 440 { 441 if (action & TK_CLEAR_NTP) { 442 tk->ntp_error = 0; 443 ntp_clear(); 444 } 445 update_vsyscall(tk); 446 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET); 447 448 tk_update_ktime_data(tk); 449 450 if (action & TK_MIRROR) 451 memcpy(&shadow_timekeeper, &tk_core.timekeeper, 452 sizeof(tk_core.timekeeper)); 453 454 update_fast_timekeeper(tk); 455 } 456 457 /** 458 * timekeeping_forward_now - update clock to the current time 459 * 460 * Forward the current clock to update its state since the last call to 461 * update_wall_time(). This is useful before significant clock changes, 462 * as it avoids having to deal with this time offset explicitly. 463 */ 464 static void timekeeping_forward_now(struct timekeeper *tk) 465 { 466 struct clocksource *clock = tk->tkr.clock; 467 cycle_t cycle_now, delta; 468 s64 nsec; 469 470 cycle_now = tk->tkr.read(clock); 471 delta = clocksource_delta(cycle_now, tk->tkr.cycle_last, tk->tkr.mask); 472 tk->tkr.cycle_last = cycle_now; 473 474 tk->tkr.xtime_nsec += delta * tk->tkr.mult; 475 476 /* If arch requires, add in get_arch_timeoffset() */ 477 tk->tkr.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr.shift; 478 479 tk_normalize_xtime(tk); 480 481 nsec = clocksource_cyc2ns(delta, clock->mult, clock->shift); 482 timespec64_add_ns(&tk->raw_time, nsec); 483 } 484 485 /** 486 * __getnstimeofday64 - Returns the time of day in a timespec64. 487 * @ts: pointer to the timespec to be set 488 * 489 * Updates the time of day in the timespec. 490 * Returns 0 on success, or -ve when suspended (timespec will be undefined). 491 */ 492 int __getnstimeofday64(struct timespec64 *ts) 493 { 494 struct timekeeper *tk = &tk_core.timekeeper; 495 unsigned long seq; 496 s64 nsecs = 0; 497 498 do { 499 seq = read_seqcount_begin(&tk_core.seq); 500 501 ts->tv_sec = tk->xtime_sec; 502 nsecs = timekeeping_get_ns(&tk->tkr); 503 504 } while (read_seqcount_retry(&tk_core.seq, seq)); 505 506 ts->tv_nsec = 0; 507 timespec64_add_ns(ts, nsecs); 508 509 /* 510 * Do not bail out early, in case there were callers still using 511 * the value, even in the face of the WARN_ON. 512 */ 513 if (unlikely(timekeeping_suspended)) 514 return -EAGAIN; 515 return 0; 516 } 517 EXPORT_SYMBOL(__getnstimeofday64); 518 519 /** 520 * getnstimeofday64 - Returns the time of day in a timespec64. 521 * @ts: pointer to the timespec to be set 522 * 523 * Returns the time of day in a timespec (WARN if suspended). 524 */ 525 void getnstimeofday64(struct timespec64 *ts) 526 { 527 WARN_ON(__getnstimeofday64(ts)); 528 } 529 EXPORT_SYMBOL(getnstimeofday64); 530 531 ktime_t ktime_get(void) 532 { 533 struct timekeeper *tk = &tk_core.timekeeper; 534 unsigned int seq; 535 ktime_t base; 536 s64 nsecs; 537 538 WARN_ON(timekeeping_suspended); 539 540 do { 541 seq = read_seqcount_begin(&tk_core.seq); 542 base = tk->tkr.base_mono; 543 nsecs = timekeeping_get_ns(&tk->tkr); 544 545 } while (read_seqcount_retry(&tk_core.seq, seq)); 546 547 return ktime_add_ns(base, nsecs); 548 } 549 EXPORT_SYMBOL_GPL(ktime_get); 550 551 static ktime_t *offsets[TK_OFFS_MAX] = { 552 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real, 553 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot, 554 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai, 555 }; 556 557 ktime_t ktime_get_with_offset(enum tk_offsets offs) 558 { 559 struct timekeeper *tk = &tk_core.timekeeper; 560 unsigned int seq; 561 ktime_t base, *offset = offsets[offs]; 562 s64 nsecs; 563 564 WARN_ON(timekeeping_suspended); 565 566 do { 567 seq = read_seqcount_begin(&tk_core.seq); 568 base = ktime_add(tk->tkr.base_mono, *offset); 569 nsecs = timekeeping_get_ns(&tk->tkr); 570 571 } while (read_seqcount_retry(&tk_core.seq, seq)); 572 573 return ktime_add_ns(base, nsecs); 574 575 } 576 EXPORT_SYMBOL_GPL(ktime_get_with_offset); 577 578 /** 579 * ktime_mono_to_any() - convert mononotic time to any other time 580 * @tmono: time to convert. 581 * @offs: which offset to use 582 */ 583 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs) 584 { 585 ktime_t *offset = offsets[offs]; 586 unsigned long seq; 587 ktime_t tconv; 588 589 do { 590 seq = read_seqcount_begin(&tk_core.seq); 591 tconv = ktime_add(tmono, *offset); 592 } while (read_seqcount_retry(&tk_core.seq, seq)); 593 594 return tconv; 595 } 596 EXPORT_SYMBOL_GPL(ktime_mono_to_any); 597 598 /** 599 * ktime_get_raw - Returns the raw monotonic time in ktime_t format 600 */ 601 ktime_t ktime_get_raw(void) 602 { 603 struct timekeeper *tk = &tk_core.timekeeper; 604 unsigned int seq; 605 ktime_t base; 606 s64 nsecs; 607 608 do { 609 seq = read_seqcount_begin(&tk_core.seq); 610 base = tk->base_raw; 611 nsecs = timekeeping_get_ns_raw(tk); 612 613 } while (read_seqcount_retry(&tk_core.seq, seq)); 614 615 return ktime_add_ns(base, nsecs); 616 } 617 EXPORT_SYMBOL_GPL(ktime_get_raw); 618 619 /** 620 * ktime_get_ts64 - get the monotonic clock in timespec64 format 621 * @ts: pointer to timespec variable 622 * 623 * The function calculates the monotonic clock from the realtime 624 * clock and the wall_to_monotonic offset and stores the result 625 * in normalized timespec format in the variable pointed to by @ts. 626 */ 627 void ktime_get_ts64(struct timespec64 *ts) 628 { 629 struct timekeeper *tk = &tk_core.timekeeper; 630 struct timespec64 tomono; 631 s64 nsec; 632 unsigned int seq; 633 634 WARN_ON(timekeeping_suspended); 635 636 do { 637 seq = read_seqcount_begin(&tk_core.seq); 638 ts->tv_sec = tk->xtime_sec; 639 nsec = timekeeping_get_ns(&tk->tkr); 640 tomono = tk->wall_to_monotonic; 641 642 } while (read_seqcount_retry(&tk_core.seq, seq)); 643 644 ts->tv_sec += tomono.tv_sec; 645 ts->tv_nsec = 0; 646 timespec64_add_ns(ts, nsec + tomono.tv_nsec); 647 } 648 EXPORT_SYMBOL_GPL(ktime_get_ts64); 649 650 #ifdef CONFIG_NTP_PPS 651 652 /** 653 * getnstime_raw_and_real - get day and raw monotonic time in timespec format 654 * @ts_raw: pointer to the timespec to be set to raw monotonic time 655 * @ts_real: pointer to the timespec to be set to the time of day 656 * 657 * This function reads both the time of day and raw monotonic time at the 658 * same time atomically and stores the resulting timestamps in timespec 659 * format. 660 */ 661 void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) 662 { 663 struct timekeeper *tk = &tk_core.timekeeper; 664 unsigned long seq; 665 s64 nsecs_raw, nsecs_real; 666 667 WARN_ON_ONCE(timekeeping_suspended); 668 669 do { 670 seq = read_seqcount_begin(&tk_core.seq); 671 672 *ts_raw = timespec64_to_timespec(tk->raw_time); 673 ts_real->tv_sec = tk->xtime_sec; 674 ts_real->tv_nsec = 0; 675 676 nsecs_raw = timekeeping_get_ns_raw(tk); 677 nsecs_real = timekeeping_get_ns(&tk->tkr); 678 679 } while (read_seqcount_retry(&tk_core.seq, seq)); 680 681 timespec_add_ns(ts_raw, nsecs_raw); 682 timespec_add_ns(ts_real, nsecs_real); 683 } 684 EXPORT_SYMBOL(getnstime_raw_and_real); 685 686 #endif /* CONFIG_NTP_PPS */ 687 688 /** 689 * do_gettimeofday - Returns the time of day in a timeval 690 * @tv: pointer to the timeval to be set 691 * 692 * NOTE: Users should be converted to using getnstimeofday() 693 */ 694 void do_gettimeofday(struct timeval *tv) 695 { 696 struct timespec64 now; 697 698 getnstimeofday64(&now); 699 tv->tv_sec = now.tv_sec; 700 tv->tv_usec = now.tv_nsec/1000; 701 } 702 EXPORT_SYMBOL(do_gettimeofday); 703 704 /** 705 * do_settimeofday - Sets the time of day 706 * @tv: pointer to the timespec variable containing the new time 707 * 708 * Sets the time of day to the new time and update NTP and notify hrtimers 709 */ 710 int do_settimeofday(const struct timespec *tv) 711 { 712 struct timekeeper *tk = &tk_core.timekeeper; 713 struct timespec64 ts_delta, xt, tmp; 714 unsigned long flags; 715 716 if (!timespec_valid_strict(tv)) 717 return -EINVAL; 718 719 raw_spin_lock_irqsave(&timekeeper_lock, flags); 720 write_seqcount_begin(&tk_core.seq); 721 722 timekeeping_forward_now(tk); 723 724 xt = tk_xtime(tk); 725 ts_delta.tv_sec = tv->tv_sec - xt.tv_sec; 726 ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec; 727 728 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta)); 729 730 tmp = timespec_to_timespec64(*tv); 731 tk_set_xtime(tk, &tmp); 732 733 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); 734 735 write_seqcount_end(&tk_core.seq); 736 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 737 738 /* signal hrtimers about time change */ 739 clock_was_set(); 740 741 return 0; 742 } 743 EXPORT_SYMBOL(do_settimeofday); 744 745 /** 746 * timekeeping_inject_offset - Adds or subtracts from the current time. 747 * @tv: pointer to the timespec variable containing the offset 748 * 749 * Adds or subtracts an offset value from the current time. 750 */ 751 int timekeeping_inject_offset(struct timespec *ts) 752 { 753 struct timekeeper *tk = &tk_core.timekeeper; 754 unsigned long flags; 755 struct timespec64 ts64, tmp; 756 int ret = 0; 757 758 if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) 759 return -EINVAL; 760 761 ts64 = timespec_to_timespec64(*ts); 762 763 raw_spin_lock_irqsave(&timekeeper_lock, flags); 764 write_seqcount_begin(&tk_core.seq); 765 766 timekeeping_forward_now(tk); 767 768 /* Make sure the proposed value is valid */ 769 tmp = timespec64_add(tk_xtime(tk), ts64); 770 if (!timespec64_valid_strict(&tmp)) { 771 ret = -EINVAL; 772 goto error; 773 } 774 775 tk_xtime_add(tk, &ts64); 776 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64)); 777 778 error: /* even if we error out, we forwarded the time, so call update */ 779 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); 780 781 write_seqcount_end(&tk_core.seq); 782 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 783 784 /* signal hrtimers about time change */ 785 clock_was_set(); 786 787 return ret; 788 } 789 EXPORT_SYMBOL(timekeeping_inject_offset); 790 791 792 /** 793 * timekeeping_get_tai_offset - Returns current TAI offset from UTC 794 * 795 */ 796 s32 timekeeping_get_tai_offset(void) 797 { 798 struct timekeeper *tk = &tk_core.timekeeper; 799 unsigned int seq; 800 s32 ret; 801 802 do { 803 seq = read_seqcount_begin(&tk_core.seq); 804 ret = tk->tai_offset; 805 } while (read_seqcount_retry(&tk_core.seq, seq)); 806 807 return ret; 808 } 809 810 /** 811 * __timekeeping_set_tai_offset - Lock free worker function 812 * 813 */ 814 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset) 815 { 816 tk->tai_offset = tai_offset; 817 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0)); 818 } 819 820 /** 821 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC 822 * 823 */ 824 void timekeeping_set_tai_offset(s32 tai_offset) 825 { 826 struct timekeeper *tk = &tk_core.timekeeper; 827 unsigned long flags; 828 829 raw_spin_lock_irqsave(&timekeeper_lock, flags); 830 write_seqcount_begin(&tk_core.seq); 831 __timekeeping_set_tai_offset(tk, tai_offset); 832 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); 833 write_seqcount_end(&tk_core.seq); 834 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 835 clock_was_set(); 836 } 837 838 /** 839 * change_clocksource - Swaps clocksources if a new one is available 840 * 841 * Accumulates current time interval and initializes new clocksource 842 */ 843 static int change_clocksource(void *data) 844 { 845 struct timekeeper *tk = &tk_core.timekeeper; 846 struct clocksource *new, *old; 847 unsigned long flags; 848 849 new = (struct clocksource *) data; 850 851 raw_spin_lock_irqsave(&timekeeper_lock, flags); 852 write_seqcount_begin(&tk_core.seq); 853 854 timekeeping_forward_now(tk); 855 /* 856 * If the cs is in module, get a module reference. Succeeds 857 * for built-in code (owner == NULL) as well. 858 */ 859 if (try_module_get(new->owner)) { 860 if (!new->enable || new->enable(new) == 0) { 861 old = tk->tkr.clock; 862 tk_setup_internals(tk, new); 863 if (old->disable) 864 old->disable(old); 865 module_put(old->owner); 866 } else { 867 module_put(new->owner); 868 } 869 } 870 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); 871 872 write_seqcount_end(&tk_core.seq); 873 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 874 875 return 0; 876 } 877 878 /** 879 * timekeeping_notify - Install a new clock source 880 * @clock: pointer to the clock source 881 * 882 * This function is called from clocksource.c after a new, better clock 883 * source has been registered. The caller holds the clocksource_mutex. 884 */ 885 int timekeeping_notify(struct clocksource *clock) 886 { 887 struct timekeeper *tk = &tk_core.timekeeper; 888 889 if (tk->tkr.clock == clock) 890 return 0; 891 stop_machine(change_clocksource, clock, NULL); 892 tick_clock_notify(); 893 return tk->tkr.clock == clock ? 0 : -1; 894 } 895 896 /** 897 * getrawmonotonic - Returns the raw monotonic time in a timespec 898 * @ts: pointer to the timespec to be set 899 * 900 * Returns the raw monotonic time (completely un-modified by ntp) 901 */ 902 void getrawmonotonic(struct timespec *ts) 903 { 904 struct timekeeper *tk = &tk_core.timekeeper; 905 struct timespec64 ts64; 906 unsigned long seq; 907 s64 nsecs; 908 909 do { 910 seq = read_seqcount_begin(&tk_core.seq); 911 nsecs = timekeeping_get_ns_raw(tk); 912 ts64 = tk->raw_time; 913 914 } while (read_seqcount_retry(&tk_core.seq, seq)); 915 916 timespec64_add_ns(&ts64, nsecs); 917 *ts = timespec64_to_timespec(ts64); 918 } 919 EXPORT_SYMBOL(getrawmonotonic); 920 921 /** 922 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres 923 */ 924 int timekeeping_valid_for_hres(void) 925 { 926 struct timekeeper *tk = &tk_core.timekeeper; 927 unsigned long seq; 928 int ret; 929 930 do { 931 seq = read_seqcount_begin(&tk_core.seq); 932 933 ret = tk->tkr.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; 934 935 } while (read_seqcount_retry(&tk_core.seq, seq)); 936 937 return ret; 938 } 939 940 /** 941 * timekeeping_max_deferment - Returns max time the clocksource can be deferred 942 */ 943 u64 timekeeping_max_deferment(void) 944 { 945 struct timekeeper *tk = &tk_core.timekeeper; 946 unsigned long seq; 947 u64 ret; 948 949 do { 950 seq = read_seqcount_begin(&tk_core.seq); 951 952 ret = tk->tkr.clock->max_idle_ns; 953 954 } while (read_seqcount_retry(&tk_core.seq, seq)); 955 956 return ret; 957 } 958 959 /** 960 * read_persistent_clock - Return time from the persistent clock. 961 * 962 * Weak dummy function for arches that do not yet support it. 963 * Reads the time from the battery backed persistent clock. 964 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. 965 * 966 * XXX - Do be sure to remove it once all arches implement it. 967 */ 968 void __weak read_persistent_clock(struct timespec *ts) 969 { 970 ts->tv_sec = 0; 971 ts->tv_nsec = 0; 972 } 973 974 /** 975 * read_boot_clock - Return time of the system start. 976 * 977 * Weak dummy function for arches that do not yet support it. 978 * Function to read the exact time the system has been started. 979 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. 980 * 981 * XXX - Do be sure to remove it once all arches implement it. 982 */ 983 void __weak read_boot_clock(struct timespec *ts) 984 { 985 ts->tv_sec = 0; 986 ts->tv_nsec = 0; 987 } 988 989 /* 990 * timekeeping_init - Initializes the clocksource and common timekeeping values 991 */ 992 void __init timekeeping_init(void) 993 { 994 struct timekeeper *tk = &tk_core.timekeeper; 995 struct clocksource *clock; 996 unsigned long flags; 997 struct timespec64 now, boot, tmp; 998 struct timespec ts; 999 1000 read_persistent_clock(&ts); 1001 now = timespec_to_timespec64(ts); 1002 if (!timespec64_valid_strict(&now)) { 1003 pr_warn("WARNING: Persistent clock returned invalid value!\n" 1004 " Check your CMOS/BIOS settings.\n"); 1005 now.tv_sec = 0; 1006 now.tv_nsec = 0; 1007 } else if (now.tv_sec || now.tv_nsec) 1008 persistent_clock_exist = true; 1009 1010 read_boot_clock(&ts); 1011 boot = timespec_to_timespec64(ts); 1012 if (!timespec64_valid_strict(&boot)) { 1013 pr_warn("WARNING: Boot clock returned invalid value!\n" 1014 " Check your CMOS/BIOS settings.\n"); 1015 boot.tv_sec = 0; 1016 boot.tv_nsec = 0; 1017 } 1018 1019 raw_spin_lock_irqsave(&timekeeper_lock, flags); 1020 write_seqcount_begin(&tk_core.seq); 1021 ntp_init(); 1022 1023 clock = clocksource_default_clock(); 1024 if (clock->enable) 1025 clock->enable(clock); 1026 tk_setup_internals(tk, clock); 1027 1028 tk_set_xtime(tk, &now); 1029 tk->raw_time.tv_sec = 0; 1030 tk->raw_time.tv_nsec = 0; 1031 tk->base_raw.tv64 = 0; 1032 if (boot.tv_sec == 0 && boot.tv_nsec == 0) 1033 boot = tk_xtime(tk); 1034 1035 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec); 1036 tk_set_wall_to_mono(tk, tmp); 1037 1038 timekeeping_update(tk, TK_MIRROR); 1039 1040 write_seqcount_end(&tk_core.seq); 1041 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 1042 } 1043 1044 /* time in seconds when suspend began */ 1045 static struct timespec64 timekeeping_suspend_time; 1046 1047 /** 1048 * __timekeeping_inject_sleeptime - Internal function to add sleep interval 1049 * @delta: pointer to a timespec delta value 1050 * 1051 * Takes a timespec offset measuring a suspend interval and properly 1052 * adds the sleep offset to the timekeeping variables. 1053 */ 1054 static void __timekeeping_inject_sleeptime(struct timekeeper *tk, 1055 struct timespec64 *delta) 1056 { 1057 if (!timespec64_valid_strict(delta)) { 1058 printk_deferred(KERN_WARNING 1059 "__timekeeping_inject_sleeptime: Invalid " 1060 "sleep delta value!\n"); 1061 return; 1062 } 1063 tk_xtime_add(tk, delta); 1064 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta)); 1065 tk_update_sleep_time(tk, timespec64_to_ktime(*delta)); 1066 tk_debug_account_sleep_time(delta); 1067 } 1068 1069 /** 1070 * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values 1071 * @delta: pointer to a timespec delta value 1072 * 1073 * This hook is for architectures that cannot support read_persistent_clock 1074 * because their RTC/persistent clock is only accessible when irqs are enabled. 1075 * 1076 * This function should only be called by rtc_resume(), and allows 1077 * a suspend offset to be injected into the timekeeping values. 1078 */ 1079 void timekeeping_inject_sleeptime(struct timespec *delta) 1080 { 1081 struct timekeeper *tk = &tk_core.timekeeper; 1082 struct timespec64 tmp; 1083 unsigned long flags; 1084 1085 /* 1086 * Make sure we don't set the clock twice, as timekeeping_resume() 1087 * already did it 1088 */ 1089 if (has_persistent_clock()) 1090 return; 1091 1092 raw_spin_lock_irqsave(&timekeeper_lock, flags); 1093 write_seqcount_begin(&tk_core.seq); 1094 1095 timekeeping_forward_now(tk); 1096 1097 tmp = timespec_to_timespec64(*delta); 1098 __timekeeping_inject_sleeptime(tk, &tmp); 1099 1100 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); 1101 1102 write_seqcount_end(&tk_core.seq); 1103 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 1104 1105 /* signal hrtimers about time change */ 1106 clock_was_set(); 1107 } 1108 1109 /** 1110 * timekeeping_resume - Resumes the generic timekeeping subsystem. 1111 * 1112 * This is for the generic clocksource timekeeping. 1113 * xtime/wall_to_monotonic/jiffies/etc are 1114 * still managed by arch specific suspend/resume code. 1115 */ 1116 static void timekeeping_resume(void) 1117 { 1118 struct timekeeper *tk = &tk_core.timekeeper; 1119 struct clocksource *clock = tk->tkr.clock; 1120 unsigned long flags; 1121 struct timespec64 ts_new, ts_delta; 1122 struct timespec tmp; 1123 cycle_t cycle_now, cycle_delta; 1124 bool suspendtime_found = false; 1125 1126 read_persistent_clock(&tmp); 1127 ts_new = timespec_to_timespec64(tmp); 1128 1129 clockevents_resume(); 1130 clocksource_resume(); 1131 1132 raw_spin_lock_irqsave(&timekeeper_lock, flags); 1133 write_seqcount_begin(&tk_core.seq); 1134 1135 /* 1136 * After system resumes, we need to calculate the suspended time and 1137 * compensate it for the OS time. There are 3 sources that could be 1138 * used: Nonstop clocksource during suspend, persistent clock and rtc 1139 * device. 1140 * 1141 * One specific platform may have 1 or 2 or all of them, and the 1142 * preference will be: 1143 * suspend-nonstop clocksource -> persistent clock -> rtc 1144 * The less preferred source will only be tried if there is no better 1145 * usable source. The rtc part is handled separately in rtc core code. 1146 */ 1147 cycle_now = tk->tkr.read(clock); 1148 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) && 1149 cycle_now > tk->tkr.cycle_last) { 1150 u64 num, max = ULLONG_MAX; 1151 u32 mult = clock->mult; 1152 u32 shift = clock->shift; 1153 s64 nsec = 0; 1154 1155 cycle_delta = clocksource_delta(cycle_now, tk->tkr.cycle_last, 1156 tk->tkr.mask); 1157 1158 /* 1159 * "cycle_delta * mutl" may cause 64 bits overflow, if the 1160 * suspended time is too long. In that case we need do the 1161 * 64 bits math carefully 1162 */ 1163 do_div(max, mult); 1164 if (cycle_delta > max) { 1165 num = div64_u64(cycle_delta, max); 1166 nsec = (((u64) max * mult) >> shift) * num; 1167 cycle_delta -= num * max; 1168 } 1169 nsec += ((u64) cycle_delta * mult) >> shift; 1170 1171 ts_delta = ns_to_timespec64(nsec); 1172 suspendtime_found = true; 1173 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { 1174 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); 1175 suspendtime_found = true; 1176 } 1177 1178 if (suspendtime_found) 1179 __timekeeping_inject_sleeptime(tk, &ts_delta); 1180 1181 /* Re-base the last cycle value */ 1182 tk->tkr.cycle_last = cycle_now; 1183 tk->ntp_error = 0; 1184 timekeeping_suspended = 0; 1185 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); 1186 write_seqcount_end(&tk_core.seq); 1187 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 1188 1189 touch_softlockup_watchdog(); 1190 1191 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); 1192 1193 /* Resume hrtimers */ 1194 hrtimers_resume(); 1195 } 1196 1197 static int timekeeping_suspend(void) 1198 { 1199 struct timekeeper *tk = &tk_core.timekeeper; 1200 unsigned long flags; 1201 struct timespec64 delta, delta_delta; 1202 static struct timespec64 old_delta; 1203 struct timespec tmp; 1204 1205 read_persistent_clock(&tmp); 1206 timekeeping_suspend_time = timespec_to_timespec64(tmp); 1207 1208 /* 1209 * On some systems the persistent_clock can not be detected at 1210 * timekeeping_init by its return value, so if we see a valid 1211 * value returned, update the persistent_clock_exists flag. 1212 */ 1213 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec) 1214 persistent_clock_exist = true; 1215 1216 raw_spin_lock_irqsave(&timekeeper_lock, flags); 1217 write_seqcount_begin(&tk_core.seq); 1218 timekeeping_forward_now(tk); 1219 timekeeping_suspended = 1; 1220 1221 /* 1222 * To avoid drift caused by repeated suspend/resumes, 1223 * which each can add ~1 second drift error, 1224 * try to compensate so the difference in system time 1225 * and persistent_clock time stays close to constant. 1226 */ 1227 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time); 1228 delta_delta = timespec64_sub(delta, old_delta); 1229 if (abs(delta_delta.tv_sec) >= 2) { 1230 /* 1231 * if delta_delta is too large, assume time correction 1232 * has occured and set old_delta to the current delta. 1233 */ 1234 old_delta = delta; 1235 } else { 1236 /* Otherwise try to adjust old_system to compensate */ 1237 timekeeping_suspend_time = 1238 timespec64_add(timekeeping_suspend_time, delta_delta); 1239 } 1240 1241 timekeeping_update(tk, TK_MIRROR); 1242 write_seqcount_end(&tk_core.seq); 1243 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 1244 1245 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); 1246 clocksource_suspend(); 1247 clockevents_suspend(); 1248 1249 return 0; 1250 } 1251 1252 /* sysfs resume/suspend bits for timekeeping */ 1253 static struct syscore_ops timekeeping_syscore_ops = { 1254 .resume = timekeeping_resume, 1255 .suspend = timekeeping_suspend, 1256 }; 1257 1258 static int __init timekeeping_init_ops(void) 1259 { 1260 register_syscore_ops(&timekeeping_syscore_ops); 1261 return 0; 1262 } 1263 device_initcall(timekeeping_init_ops); 1264 1265 /* 1266 * Apply a multiplier adjustment to the timekeeper 1267 */ 1268 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk, 1269 s64 offset, 1270 bool negative, 1271 int adj_scale) 1272 { 1273 s64 interval = tk->cycle_interval; 1274 s32 mult_adj = 1; 1275 1276 if (negative) { 1277 mult_adj = -mult_adj; 1278 interval = -interval; 1279 offset = -offset; 1280 } 1281 mult_adj <<= adj_scale; 1282 interval <<= adj_scale; 1283 offset <<= adj_scale; 1284 1285 /* 1286 * So the following can be confusing. 1287 * 1288 * To keep things simple, lets assume mult_adj == 1 for now. 1289 * 1290 * When mult_adj != 1, remember that the interval and offset values 1291 * have been appropriately scaled so the math is the same. 1292 * 1293 * The basic idea here is that we're increasing the multiplier 1294 * by one, this causes the xtime_interval to be incremented by 1295 * one cycle_interval. This is because: 1296 * xtime_interval = cycle_interval * mult 1297 * So if mult is being incremented by one: 1298 * xtime_interval = cycle_interval * (mult + 1) 1299 * Its the same as: 1300 * xtime_interval = (cycle_interval * mult) + cycle_interval 1301 * Which can be shortened to: 1302 * xtime_interval += cycle_interval 1303 * 1304 * So offset stores the non-accumulated cycles. Thus the current 1305 * time (in shifted nanoseconds) is: 1306 * now = (offset * adj) + xtime_nsec 1307 * Now, even though we're adjusting the clock frequency, we have 1308 * to keep time consistent. In other words, we can't jump back 1309 * in time, and we also want to avoid jumping forward in time. 1310 * 1311 * So given the same offset value, we need the time to be the same 1312 * both before and after the freq adjustment. 1313 * now = (offset * adj_1) + xtime_nsec_1 1314 * now = (offset * adj_2) + xtime_nsec_2 1315 * So: 1316 * (offset * adj_1) + xtime_nsec_1 = 1317 * (offset * adj_2) + xtime_nsec_2 1318 * And we know: 1319 * adj_2 = adj_1 + 1 1320 * So: 1321 * (offset * adj_1) + xtime_nsec_1 = 1322 * (offset * (adj_1+1)) + xtime_nsec_2 1323 * (offset * adj_1) + xtime_nsec_1 = 1324 * (offset * adj_1) + offset + xtime_nsec_2 1325 * Canceling the sides: 1326 * xtime_nsec_1 = offset + xtime_nsec_2 1327 * Which gives us: 1328 * xtime_nsec_2 = xtime_nsec_1 - offset 1329 * Which simplfies to: 1330 * xtime_nsec -= offset 1331 * 1332 * XXX - TODO: Doc ntp_error calculation. 1333 */ 1334 tk->tkr.mult += mult_adj; 1335 tk->xtime_interval += interval; 1336 tk->tkr.xtime_nsec -= offset; 1337 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift; 1338 } 1339 1340 /* 1341 * Calculate the multiplier adjustment needed to match the frequency 1342 * specified by NTP 1343 */ 1344 static __always_inline void timekeeping_freqadjust(struct timekeeper *tk, 1345 s64 offset) 1346 { 1347 s64 interval = tk->cycle_interval; 1348 s64 xinterval = tk->xtime_interval; 1349 s64 tick_error; 1350 bool negative; 1351 u32 adj; 1352 1353 /* Remove any current error adj from freq calculation */ 1354 if (tk->ntp_err_mult) 1355 xinterval -= tk->cycle_interval; 1356 1357 tk->ntp_tick = ntp_tick_length(); 1358 1359 /* Calculate current error per tick */ 1360 tick_error = ntp_tick_length() >> tk->ntp_error_shift; 1361 tick_error -= (xinterval + tk->xtime_remainder); 1362 1363 /* Don't worry about correcting it if its small */ 1364 if (likely((tick_error >= 0) && (tick_error <= interval))) 1365 return; 1366 1367 /* preserve the direction of correction */ 1368 negative = (tick_error < 0); 1369 1370 /* Sort out the magnitude of the correction */ 1371 tick_error = abs(tick_error); 1372 for (adj = 0; tick_error > interval; adj++) 1373 tick_error >>= 1; 1374 1375 /* scale the corrections */ 1376 timekeeping_apply_adjustment(tk, offset, negative, adj); 1377 } 1378 1379 /* 1380 * Adjust the timekeeper's multiplier to the correct frequency 1381 * and also to reduce the accumulated error value. 1382 */ 1383 static void timekeeping_adjust(struct timekeeper *tk, s64 offset) 1384 { 1385 /* Correct for the current frequency error */ 1386 timekeeping_freqadjust(tk, offset); 1387 1388 /* Next make a small adjustment to fix any cumulative error */ 1389 if (!tk->ntp_err_mult && (tk->ntp_error > 0)) { 1390 tk->ntp_err_mult = 1; 1391 timekeeping_apply_adjustment(tk, offset, 0, 0); 1392 } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) { 1393 /* Undo any existing error adjustment */ 1394 timekeeping_apply_adjustment(tk, offset, 1, 0); 1395 tk->ntp_err_mult = 0; 1396 } 1397 1398 if (unlikely(tk->tkr.clock->maxadj && 1399 (tk->tkr.mult > tk->tkr.clock->mult + tk->tkr.clock->maxadj))) { 1400 printk_once(KERN_WARNING 1401 "Adjusting %s more than 11%% (%ld vs %ld)\n", 1402 tk->tkr.clock->name, (long)tk->tkr.mult, 1403 (long)tk->tkr.clock->mult + tk->tkr.clock->maxadj); 1404 } 1405 1406 /* 1407 * It may be possible that when we entered this function, xtime_nsec 1408 * was very small. Further, if we're slightly speeding the clocksource 1409 * in the code above, its possible the required corrective factor to 1410 * xtime_nsec could cause it to underflow. 1411 * 1412 * Now, since we already accumulated the second, cannot simply roll 1413 * the accumulated second back, since the NTP subsystem has been 1414 * notified via second_overflow. So instead we push xtime_nsec forward 1415 * by the amount we underflowed, and add that amount into the error. 1416 * 1417 * We'll correct this error next time through this function, when 1418 * xtime_nsec is not as small. 1419 */ 1420 if (unlikely((s64)tk->tkr.xtime_nsec < 0)) { 1421 s64 neg = -(s64)tk->tkr.xtime_nsec; 1422 tk->tkr.xtime_nsec = 0; 1423 tk->ntp_error += neg << tk->ntp_error_shift; 1424 } 1425 } 1426 1427 /** 1428 * accumulate_nsecs_to_secs - Accumulates nsecs into secs 1429 * 1430 * Helper function that accumulates a the nsecs greater then a second 1431 * from the xtime_nsec field to the xtime_secs field. 1432 * It also calls into the NTP code to handle leapsecond processing. 1433 * 1434 */ 1435 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk) 1436 { 1437 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr.shift; 1438 unsigned int clock_set = 0; 1439 1440 while (tk->tkr.xtime_nsec >= nsecps) { 1441 int leap; 1442 1443 tk->tkr.xtime_nsec -= nsecps; 1444 tk->xtime_sec++; 1445 1446 /* Figure out if its a leap sec and apply if needed */ 1447 leap = second_overflow(tk->xtime_sec); 1448 if (unlikely(leap)) { 1449 struct timespec64 ts; 1450 1451 tk->xtime_sec += leap; 1452 1453 ts.tv_sec = leap; 1454 ts.tv_nsec = 0; 1455 tk_set_wall_to_mono(tk, 1456 timespec64_sub(tk->wall_to_monotonic, ts)); 1457 1458 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap); 1459 1460 clock_set = TK_CLOCK_WAS_SET; 1461 } 1462 } 1463 return clock_set; 1464 } 1465 1466 /** 1467 * logarithmic_accumulation - shifted accumulation of cycles 1468 * 1469 * This functions accumulates a shifted interval of cycles into 1470 * into a shifted interval nanoseconds. Allows for O(log) accumulation 1471 * loop. 1472 * 1473 * Returns the unconsumed cycles. 1474 */ 1475 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset, 1476 u32 shift, 1477 unsigned int *clock_set) 1478 { 1479 cycle_t interval = tk->cycle_interval << shift; 1480 u64 raw_nsecs; 1481 1482 /* If the offset is smaller then a shifted interval, do nothing */ 1483 if (offset < interval) 1484 return offset; 1485 1486 /* Accumulate one shifted interval */ 1487 offset -= interval; 1488 tk->tkr.cycle_last += interval; 1489 1490 tk->tkr.xtime_nsec += tk->xtime_interval << shift; 1491 *clock_set |= accumulate_nsecs_to_secs(tk); 1492 1493 /* Accumulate raw time */ 1494 raw_nsecs = (u64)tk->raw_interval << shift; 1495 raw_nsecs += tk->raw_time.tv_nsec; 1496 if (raw_nsecs >= NSEC_PER_SEC) { 1497 u64 raw_secs = raw_nsecs; 1498 raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); 1499 tk->raw_time.tv_sec += raw_secs; 1500 } 1501 tk->raw_time.tv_nsec = raw_nsecs; 1502 1503 /* Accumulate error between NTP and clock interval */ 1504 tk->ntp_error += tk->ntp_tick << shift; 1505 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) << 1506 (tk->ntp_error_shift + shift); 1507 1508 return offset; 1509 } 1510 1511 /** 1512 * update_wall_time - Uses the current clocksource to increment the wall time 1513 * 1514 */ 1515 void update_wall_time(void) 1516 { 1517 struct timekeeper *real_tk = &tk_core.timekeeper; 1518 struct timekeeper *tk = &shadow_timekeeper; 1519 cycle_t offset; 1520 int shift = 0, maxshift; 1521 unsigned int clock_set = 0; 1522 unsigned long flags; 1523 1524 raw_spin_lock_irqsave(&timekeeper_lock, flags); 1525 1526 /* Make sure we're fully resumed: */ 1527 if (unlikely(timekeeping_suspended)) 1528 goto out; 1529 1530 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET 1531 offset = real_tk->cycle_interval; 1532 #else 1533 offset = clocksource_delta(tk->tkr.read(tk->tkr.clock), 1534 tk->tkr.cycle_last, tk->tkr.mask); 1535 #endif 1536 1537 /* Check if there's really nothing to do */ 1538 if (offset < real_tk->cycle_interval) 1539 goto out; 1540 1541 /* 1542 * With NO_HZ we may have to accumulate many cycle_intervals 1543 * (think "ticks") worth of time at once. To do this efficiently, 1544 * we calculate the largest doubling multiple of cycle_intervals 1545 * that is smaller than the offset. We then accumulate that 1546 * chunk in one go, and then try to consume the next smaller 1547 * doubled multiple. 1548 */ 1549 shift = ilog2(offset) - ilog2(tk->cycle_interval); 1550 shift = max(0, shift); 1551 /* Bound shift to one less than what overflows tick_length */ 1552 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; 1553 shift = min(shift, maxshift); 1554 while (offset >= tk->cycle_interval) { 1555 offset = logarithmic_accumulation(tk, offset, shift, 1556 &clock_set); 1557 if (offset < tk->cycle_interval<<shift) 1558 shift--; 1559 } 1560 1561 /* correct the clock when NTP error is too big */ 1562 timekeeping_adjust(tk, offset); 1563 1564 /* 1565 * XXX This can be killed once everyone converts 1566 * to the new update_vsyscall. 1567 */ 1568 old_vsyscall_fixup(tk); 1569 1570 /* 1571 * Finally, make sure that after the rounding 1572 * xtime_nsec isn't larger than NSEC_PER_SEC 1573 */ 1574 clock_set |= accumulate_nsecs_to_secs(tk); 1575 1576 write_seqcount_begin(&tk_core.seq); 1577 /* 1578 * Update the real timekeeper. 1579 * 1580 * We could avoid this memcpy by switching pointers, but that 1581 * requires changes to all other timekeeper usage sites as 1582 * well, i.e. move the timekeeper pointer getter into the 1583 * spinlocked/seqcount protected sections. And we trade this 1584 * memcpy under the tk_core.seq against one before we start 1585 * updating. 1586 */ 1587 memcpy(real_tk, tk, sizeof(*tk)); 1588 timekeeping_update(real_tk, clock_set); 1589 write_seqcount_end(&tk_core.seq); 1590 out: 1591 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 1592 if (clock_set) 1593 /* Have to call _delayed version, since in irq context*/ 1594 clock_was_set_delayed(); 1595 } 1596 1597 /** 1598 * getboottime - Return the real time of system boot. 1599 * @ts: pointer to the timespec to be set 1600 * 1601 * Returns the wall-time of boot in a timespec. 1602 * 1603 * This is based on the wall_to_monotonic offset and the total suspend 1604 * time. Calls to settimeofday will affect the value returned (which 1605 * basically means that however wrong your real time clock is at boot time, 1606 * you get the right time here). 1607 */ 1608 void getboottime(struct timespec *ts) 1609 { 1610 struct timekeeper *tk = &tk_core.timekeeper; 1611 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot); 1612 1613 *ts = ktime_to_timespec(t); 1614 } 1615 EXPORT_SYMBOL_GPL(getboottime); 1616 1617 unsigned long get_seconds(void) 1618 { 1619 struct timekeeper *tk = &tk_core.timekeeper; 1620 1621 return tk->xtime_sec; 1622 } 1623 EXPORT_SYMBOL(get_seconds); 1624 1625 struct timespec __current_kernel_time(void) 1626 { 1627 struct timekeeper *tk = &tk_core.timekeeper; 1628 1629 return timespec64_to_timespec(tk_xtime(tk)); 1630 } 1631 1632 struct timespec current_kernel_time(void) 1633 { 1634 struct timekeeper *tk = &tk_core.timekeeper; 1635 struct timespec64 now; 1636 unsigned long seq; 1637 1638 do { 1639 seq = read_seqcount_begin(&tk_core.seq); 1640 1641 now = tk_xtime(tk); 1642 } while (read_seqcount_retry(&tk_core.seq, seq)); 1643 1644 return timespec64_to_timespec(now); 1645 } 1646 EXPORT_SYMBOL(current_kernel_time); 1647 1648 struct timespec get_monotonic_coarse(void) 1649 { 1650 struct timekeeper *tk = &tk_core.timekeeper; 1651 struct timespec64 now, mono; 1652 unsigned long seq; 1653 1654 do { 1655 seq = read_seqcount_begin(&tk_core.seq); 1656 1657 now = tk_xtime(tk); 1658 mono = tk->wall_to_monotonic; 1659 } while (read_seqcount_retry(&tk_core.seq, seq)); 1660 1661 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec, 1662 now.tv_nsec + mono.tv_nsec); 1663 1664 return timespec64_to_timespec(now); 1665 } 1666 1667 /* 1668 * Must hold jiffies_lock 1669 */ 1670 void do_timer(unsigned long ticks) 1671 { 1672 jiffies_64 += ticks; 1673 calc_global_load(ticks); 1674 } 1675 1676 /** 1677 * ktime_get_update_offsets_tick - hrtimer helper 1678 * @offs_real: pointer to storage for monotonic -> realtime offset 1679 * @offs_boot: pointer to storage for monotonic -> boottime offset 1680 * @offs_tai: pointer to storage for monotonic -> clock tai offset 1681 * 1682 * Returns monotonic time at last tick and various offsets 1683 */ 1684 ktime_t ktime_get_update_offsets_tick(ktime_t *offs_real, ktime_t *offs_boot, 1685 ktime_t *offs_tai) 1686 { 1687 struct timekeeper *tk = &tk_core.timekeeper; 1688 unsigned int seq; 1689 ktime_t base; 1690 u64 nsecs; 1691 1692 do { 1693 seq = read_seqcount_begin(&tk_core.seq); 1694 1695 base = tk->tkr.base_mono; 1696 nsecs = tk->tkr.xtime_nsec >> tk->tkr.shift; 1697 1698 *offs_real = tk->offs_real; 1699 *offs_boot = tk->offs_boot; 1700 *offs_tai = tk->offs_tai; 1701 } while (read_seqcount_retry(&tk_core.seq, seq)); 1702 1703 return ktime_add_ns(base, nsecs); 1704 } 1705 1706 #ifdef CONFIG_HIGH_RES_TIMERS 1707 /** 1708 * ktime_get_update_offsets_now - hrtimer helper 1709 * @offs_real: pointer to storage for monotonic -> realtime offset 1710 * @offs_boot: pointer to storage for monotonic -> boottime offset 1711 * @offs_tai: pointer to storage for monotonic -> clock tai offset 1712 * 1713 * Returns current monotonic time and updates the offsets 1714 * Called from hrtimer_interrupt() or retrigger_next_event() 1715 */ 1716 ktime_t ktime_get_update_offsets_now(ktime_t *offs_real, ktime_t *offs_boot, 1717 ktime_t *offs_tai) 1718 { 1719 struct timekeeper *tk = &tk_core.timekeeper; 1720 unsigned int seq; 1721 ktime_t base; 1722 u64 nsecs; 1723 1724 do { 1725 seq = read_seqcount_begin(&tk_core.seq); 1726 1727 base = tk->tkr.base_mono; 1728 nsecs = timekeeping_get_ns(&tk->tkr); 1729 1730 *offs_real = tk->offs_real; 1731 *offs_boot = tk->offs_boot; 1732 *offs_tai = tk->offs_tai; 1733 } while (read_seqcount_retry(&tk_core.seq, seq)); 1734 1735 return ktime_add_ns(base, nsecs); 1736 } 1737 #endif 1738 1739 /** 1740 * do_adjtimex() - Accessor function to NTP __do_adjtimex function 1741 */ 1742 int do_adjtimex(struct timex *txc) 1743 { 1744 struct timekeeper *tk = &tk_core.timekeeper; 1745 unsigned long flags; 1746 struct timespec64 ts; 1747 s32 orig_tai, tai; 1748 int ret; 1749 1750 /* Validate the data before disabling interrupts */ 1751 ret = ntp_validate_timex(txc); 1752 if (ret) 1753 return ret; 1754 1755 if (txc->modes & ADJ_SETOFFSET) { 1756 struct timespec delta; 1757 delta.tv_sec = txc->time.tv_sec; 1758 delta.tv_nsec = txc->time.tv_usec; 1759 if (!(txc->modes & ADJ_NANO)) 1760 delta.tv_nsec *= 1000; 1761 ret = timekeeping_inject_offset(&delta); 1762 if (ret) 1763 return ret; 1764 } 1765 1766 getnstimeofday64(&ts); 1767 1768 raw_spin_lock_irqsave(&timekeeper_lock, flags); 1769 write_seqcount_begin(&tk_core.seq); 1770 1771 orig_tai = tai = tk->tai_offset; 1772 ret = __do_adjtimex(txc, &ts, &tai); 1773 1774 if (tai != orig_tai) { 1775 __timekeeping_set_tai_offset(tk, tai); 1776 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); 1777 } 1778 write_seqcount_end(&tk_core.seq); 1779 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 1780 1781 if (tai != orig_tai) 1782 clock_was_set(); 1783 1784 ntp_notify_cmos_timer(); 1785 1786 return ret; 1787 } 1788 1789 #ifdef CONFIG_NTP_PPS 1790 /** 1791 * hardpps() - Accessor function to NTP __hardpps function 1792 */ 1793 void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) 1794 { 1795 unsigned long flags; 1796 1797 raw_spin_lock_irqsave(&timekeeper_lock, flags); 1798 write_seqcount_begin(&tk_core.seq); 1799 1800 __hardpps(phase_ts, raw_ts); 1801 1802 write_seqcount_end(&tk_core.seq); 1803 raw_spin_unlock_irqrestore(&timekeeper_lock, flags); 1804 } 1805 EXPORT_SYMBOL(hardpps); 1806 #endif 1807 1808 /** 1809 * xtime_update() - advances the timekeeping infrastructure 1810 * @ticks: number of ticks, that have elapsed since the last call. 1811 * 1812 * Must be called with interrupts disabled. 1813 */ 1814 void xtime_update(unsigned long ticks) 1815 { 1816 write_seqlock(&jiffies_lock); 1817 do_timer(ticks); 1818 write_sequnlock(&jiffies_lock); 1819 update_wall_time(); 1820 } 1821