1 /* 2 * linux/kernel/time.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * 6 * This file contains the interface functions for the various 7 * time related system calls: time, stime, gettimeofday, settimeofday, 8 * adjtime 9 */ 10 /* 11 * Modification history kernel/time.c 12 * 13 * 1993-09-02 Philip Gladstone 14 * Created file with time related functions from sched/core.c and adjtimex() 15 * 1993-10-08 Torsten Duwe 16 * adjtime interface update and CMOS clock write code 17 * 1995-08-13 Torsten Duwe 18 * kernel PLL updated to 1994-12-13 specs (rfc-1589) 19 * 1999-01-16 Ulrich Windl 20 * Introduced error checking for many cases in adjtimex(). 21 * Updated NTP code according to technical memorandum Jan '96 22 * "A Kernel Model for Precision Timekeeping" by Dave Mills 23 * Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10) 24 * (Even though the technical memorandum forbids it) 25 * 2004-07-14 Christoph Lameter 26 * Added getnstimeofday to allow the posix timer functions to return 27 * with nanosecond accuracy 28 */ 29 30 #include <linux/export.h> 31 #include <linux/kernel.h> 32 #include <linux/timex.h> 33 #include <linux/capability.h> 34 #include <linux/timekeeper_internal.h> 35 #include <linux/errno.h> 36 #include <linux/syscalls.h> 37 #include <linux/security.h> 38 #include <linux/fs.h> 39 #include <linux/math64.h> 40 #include <linux/ptrace.h> 41 42 #include <linux/uaccess.h> 43 #include <linux/compat.h> 44 #include <asm/unistd.h> 45 46 #include <generated/timeconst.h> 47 #include "timekeeping.h" 48 49 /* 50 * The timezone where the local system is located. Used as a default by some 51 * programs who obtain this value by using gettimeofday. 52 */ 53 struct timezone sys_tz; 54 55 EXPORT_SYMBOL(sys_tz); 56 57 #ifdef __ARCH_WANT_SYS_TIME 58 59 /* 60 * sys_time() can be implemented in user-level using 61 * sys_gettimeofday(). Is this for backwards compatibility? If so, 62 * why not move it into the appropriate arch directory (for those 63 * architectures that need it). 64 */ 65 SYSCALL_DEFINE1(time, time_t __user *, tloc) 66 { 67 time_t i = (time_t)ktime_get_real_seconds(); 68 69 if (tloc) { 70 if (put_user(i,tloc)) 71 return -EFAULT; 72 } 73 force_successful_syscall_return(); 74 return i; 75 } 76 77 /* 78 * sys_stime() can be implemented in user-level using 79 * sys_settimeofday(). Is this for backwards compatibility? If so, 80 * why not move it into the appropriate arch directory (for those 81 * architectures that need it). 82 */ 83 84 SYSCALL_DEFINE1(stime, time_t __user *, tptr) 85 { 86 struct timespec64 tv; 87 int err; 88 89 if (get_user(tv.tv_sec, tptr)) 90 return -EFAULT; 91 92 tv.tv_nsec = 0; 93 94 err = security_settime64(&tv, NULL); 95 if (err) 96 return err; 97 98 do_settimeofday64(&tv); 99 return 0; 100 } 101 102 #endif /* __ARCH_WANT_SYS_TIME */ 103 104 #ifdef CONFIG_COMPAT 105 #ifdef __ARCH_WANT_COMPAT_SYS_TIME 106 107 /* compat_time_t is a 32 bit "long" and needs to get converted. */ 108 COMPAT_SYSCALL_DEFINE1(time, compat_time_t __user *, tloc) 109 { 110 compat_time_t i; 111 112 i = (compat_time_t)ktime_get_real_seconds(); 113 114 if (tloc) { 115 if (put_user(i,tloc)) 116 return -EFAULT; 117 } 118 force_successful_syscall_return(); 119 return i; 120 } 121 122 COMPAT_SYSCALL_DEFINE1(stime, compat_time_t __user *, tptr) 123 { 124 struct timespec64 tv; 125 int err; 126 127 if (get_user(tv.tv_sec, tptr)) 128 return -EFAULT; 129 130 tv.tv_nsec = 0; 131 132 err = security_settime64(&tv, NULL); 133 if (err) 134 return err; 135 136 do_settimeofday64(&tv); 137 return 0; 138 } 139 140 #endif /* __ARCH_WANT_COMPAT_SYS_TIME */ 141 #endif 142 143 SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv, 144 struct timezone __user *, tz) 145 { 146 if (likely(tv != NULL)) { 147 struct timeval ktv; 148 do_gettimeofday(&ktv); 149 if (copy_to_user(tv, &ktv, sizeof(ktv))) 150 return -EFAULT; 151 } 152 if (unlikely(tz != NULL)) { 153 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) 154 return -EFAULT; 155 } 156 return 0; 157 } 158 159 /* 160 * In case for some reason the CMOS clock has not already been running 161 * in UTC, but in some local time: The first time we set the timezone, 162 * we will warp the clock so that it is ticking UTC time instead of 163 * local time. Presumably, if someone is setting the timezone then we 164 * are running in an environment where the programs understand about 165 * timezones. This should be done at boot time in the /etc/rc script, 166 * as soon as possible, so that the clock can be set right. Otherwise, 167 * various programs will get confused when the clock gets warped. 168 */ 169 170 int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz) 171 { 172 static int firsttime = 1; 173 int error = 0; 174 175 if (tv && !timespec64_valid(tv)) 176 return -EINVAL; 177 178 error = security_settime64(tv, tz); 179 if (error) 180 return error; 181 182 if (tz) { 183 /* Verify we're witin the +-15 hrs range */ 184 if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60) 185 return -EINVAL; 186 187 sys_tz = *tz; 188 update_vsyscall_tz(); 189 if (firsttime) { 190 firsttime = 0; 191 if (!tv) 192 timekeeping_warp_clock(); 193 } 194 } 195 if (tv) 196 return do_settimeofday64(tv); 197 return 0; 198 } 199 200 SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, 201 struct timezone __user *, tz) 202 { 203 struct timespec64 new_ts; 204 struct timeval user_tv; 205 struct timezone new_tz; 206 207 if (tv) { 208 if (copy_from_user(&user_tv, tv, sizeof(*tv))) 209 return -EFAULT; 210 211 if (!timeval_valid(&user_tv)) 212 return -EINVAL; 213 214 new_ts.tv_sec = user_tv.tv_sec; 215 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; 216 } 217 if (tz) { 218 if (copy_from_user(&new_tz, tz, sizeof(*tz))) 219 return -EFAULT; 220 } 221 222 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL); 223 } 224 225 #ifdef CONFIG_COMPAT 226 COMPAT_SYSCALL_DEFINE2(gettimeofday, struct compat_timeval __user *, tv, 227 struct timezone __user *, tz) 228 { 229 if (tv) { 230 struct timeval ktv; 231 232 do_gettimeofday(&ktv); 233 if (compat_put_timeval(&ktv, tv)) 234 return -EFAULT; 235 } 236 if (tz) { 237 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) 238 return -EFAULT; 239 } 240 241 return 0; 242 } 243 244 COMPAT_SYSCALL_DEFINE2(settimeofday, struct compat_timeval __user *, tv, 245 struct timezone __user *, tz) 246 { 247 struct timespec64 new_ts; 248 struct timeval user_tv; 249 struct timezone new_tz; 250 251 if (tv) { 252 if (compat_get_timeval(&user_tv, tv)) 253 return -EFAULT; 254 new_ts.tv_sec = user_tv.tv_sec; 255 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; 256 } 257 if (tz) { 258 if (copy_from_user(&new_tz, tz, sizeof(*tz))) 259 return -EFAULT; 260 } 261 262 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL); 263 } 264 #endif 265 266 SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p) 267 { 268 struct timex txc; /* Local copy of parameter */ 269 int ret; 270 271 /* Copy the user data space into the kernel copy 272 * structure. But bear in mind that the structures 273 * may change 274 */ 275 if (copy_from_user(&txc, txc_p, sizeof(struct timex))) 276 return -EFAULT; 277 ret = do_adjtimex(&txc); 278 return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret; 279 } 280 281 #ifdef CONFIG_COMPAT 282 283 COMPAT_SYSCALL_DEFINE1(adjtimex, struct compat_timex __user *, utp) 284 { 285 struct timex txc; 286 int err, ret; 287 288 err = compat_get_timex(&txc, utp); 289 if (err) 290 return err; 291 292 ret = do_adjtimex(&txc); 293 294 err = compat_put_timex(utp, &txc); 295 if (err) 296 return err; 297 298 return ret; 299 } 300 #endif 301 302 /* 303 * Convert jiffies to milliseconds and back. 304 * 305 * Avoid unnecessary multiplications/divisions in the 306 * two most common HZ cases: 307 */ 308 unsigned int jiffies_to_msecs(const unsigned long j) 309 { 310 #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) 311 return (MSEC_PER_SEC / HZ) * j; 312 #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) 313 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); 314 #else 315 # if BITS_PER_LONG == 32 316 return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >> 317 HZ_TO_MSEC_SHR32; 318 # else 319 return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN); 320 # endif 321 #endif 322 } 323 EXPORT_SYMBOL(jiffies_to_msecs); 324 325 unsigned int jiffies_to_usecs(const unsigned long j) 326 { 327 /* 328 * Hz usually doesn't go much further MSEC_PER_SEC. 329 * jiffies_to_usecs() and usecs_to_jiffies() depend on that. 330 */ 331 BUILD_BUG_ON(HZ > USEC_PER_SEC); 332 333 #if !(USEC_PER_SEC % HZ) 334 return (USEC_PER_SEC / HZ) * j; 335 #else 336 # if BITS_PER_LONG == 32 337 return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32; 338 # else 339 return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN; 340 # endif 341 #endif 342 } 343 EXPORT_SYMBOL(jiffies_to_usecs); 344 345 /** 346 * timespec_trunc - Truncate timespec to a granularity 347 * @t: Timespec 348 * @gran: Granularity in ns. 349 * 350 * Truncate a timespec to a granularity. Always rounds down. gran must 351 * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns). 352 */ 353 struct timespec timespec_trunc(struct timespec t, unsigned gran) 354 { 355 /* Avoid division in the common cases 1 ns and 1 s. */ 356 if (gran == 1) { 357 /* nothing */ 358 } else if (gran == NSEC_PER_SEC) { 359 t.tv_nsec = 0; 360 } else if (gran > 1 && gran < NSEC_PER_SEC) { 361 t.tv_nsec -= t.tv_nsec % gran; 362 } else { 363 WARN(1, "illegal file time granularity: %u", gran); 364 } 365 return t; 366 } 367 EXPORT_SYMBOL(timespec_trunc); 368 369 /* 370 * mktime64 - Converts date to seconds. 371 * Converts Gregorian date to seconds since 1970-01-01 00:00:00. 372 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 373 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. 374 * 375 * [For the Julian calendar (which was used in Russia before 1917, 376 * Britain & colonies before 1752, anywhere else before 1582, 377 * and is still in use by some communities) leave out the 378 * -year/100+year/400 terms, and add 10.] 379 * 380 * This algorithm was first published by Gauss (I think). 381 * 382 * A leap second can be indicated by calling this function with sec as 383 * 60 (allowable under ISO 8601). The leap second is treated the same 384 * as the following second since they don't exist in UNIX time. 385 * 386 * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight 387 * tomorrow - (allowable under ISO 8601) is supported. 388 */ 389 time64_t mktime64(const unsigned int year0, const unsigned int mon0, 390 const unsigned int day, const unsigned int hour, 391 const unsigned int min, const unsigned int sec) 392 { 393 unsigned int mon = mon0, year = year0; 394 395 /* 1..12 -> 11,12,1..10 */ 396 if (0 >= (int) (mon -= 2)) { 397 mon += 12; /* Puts Feb last since it has leap day */ 398 year -= 1; 399 } 400 401 return ((((time64_t) 402 (year/4 - year/100 + year/400 + 367*mon/12 + day) + 403 year*365 - 719499 404 )*24 + hour /* now have hours - midnight tomorrow handled here */ 405 )*60 + min /* now have minutes */ 406 )*60 + sec; /* finally seconds */ 407 } 408 EXPORT_SYMBOL(mktime64); 409 410 /** 411 * set_normalized_timespec - set timespec sec and nsec parts and normalize 412 * 413 * @ts: pointer to timespec variable to be set 414 * @sec: seconds to set 415 * @nsec: nanoseconds to set 416 * 417 * Set seconds and nanoseconds field of a timespec variable and 418 * normalize to the timespec storage format 419 * 420 * Note: The tv_nsec part is always in the range of 421 * 0 <= tv_nsec < NSEC_PER_SEC 422 * For negative values only the tv_sec field is negative ! 423 */ 424 void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec) 425 { 426 while (nsec >= NSEC_PER_SEC) { 427 /* 428 * The following asm() prevents the compiler from 429 * optimising this loop into a modulo operation. See 430 * also __iter_div_u64_rem() in include/linux/time.h 431 */ 432 asm("" : "+rm"(nsec)); 433 nsec -= NSEC_PER_SEC; 434 ++sec; 435 } 436 while (nsec < 0) { 437 asm("" : "+rm"(nsec)); 438 nsec += NSEC_PER_SEC; 439 --sec; 440 } 441 ts->tv_sec = sec; 442 ts->tv_nsec = nsec; 443 } 444 EXPORT_SYMBOL(set_normalized_timespec); 445 446 /** 447 * ns_to_timespec - Convert nanoseconds to timespec 448 * @nsec: the nanoseconds value to be converted 449 * 450 * Returns the timespec representation of the nsec parameter. 451 */ 452 struct timespec ns_to_timespec(const s64 nsec) 453 { 454 struct timespec ts; 455 s32 rem; 456 457 if (!nsec) 458 return (struct timespec) {0, 0}; 459 460 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem); 461 if (unlikely(rem < 0)) { 462 ts.tv_sec--; 463 rem += NSEC_PER_SEC; 464 } 465 ts.tv_nsec = rem; 466 467 return ts; 468 } 469 EXPORT_SYMBOL(ns_to_timespec); 470 471 /** 472 * ns_to_timeval - Convert nanoseconds to timeval 473 * @nsec: the nanoseconds value to be converted 474 * 475 * Returns the timeval representation of the nsec parameter. 476 */ 477 struct timeval ns_to_timeval(const s64 nsec) 478 { 479 struct timespec ts = ns_to_timespec(nsec); 480 struct timeval tv; 481 482 tv.tv_sec = ts.tv_sec; 483 tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000; 484 485 return tv; 486 } 487 EXPORT_SYMBOL(ns_to_timeval); 488 489 struct __kernel_old_timeval ns_to_kernel_old_timeval(const s64 nsec) 490 { 491 struct timespec64 ts = ns_to_timespec64(nsec); 492 struct __kernel_old_timeval tv; 493 494 tv.tv_sec = ts.tv_sec; 495 tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000; 496 497 return tv; 498 } 499 EXPORT_SYMBOL(ns_to_kernel_old_timeval); 500 501 /** 502 * set_normalized_timespec - set timespec sec and nsec parts and normalize 503 * 504 * @ts: pointer to timespec variable to be set 505 * @sec: seconds to set 506 * @nsec: nanoseconds to set 507 * 508 * Set seconds and nanoseconds field of a timespec variable and 509 * normalize to the timespec storage format 510 * 511 * Note: The tv_nsec part is always in the range of 512 * 0 <= tv_nsec < NSEC_PER_SEC 513 * For negative values only the tv_sec field is negative ! 514 */ 515 void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec) 516 { 517 while (nsec >= NSEC_PER_SEC) { 518 /* 519 * The following asm() prevents the compiler from 520 * optimising this loop into a modulo operation. See 521 * also __iter_div_u64_rem() in include/linux/time.h 522 */ 523 asm("" : "+rm"(nsec)); 524 nsec -= NSEC_PER_SEC; 525 ++sec; 526 } 527 while (nsec < 0) { 528 asm("" : "+rm"(nsec)); 529 nsec += NSEC_PER_SEC; 530 --sec; 531 } 532 ts->tv_sec = sec; 533 ts->tv_nsec = nsec; 534 } 535 EXPORT_SYMBOL(set_normalized_timespec64); 536 537 /** 538 * ns_to_timespec64 - Convert nanoseconds to timespec64 539 * @nsec: the nanoseconds value to be converted 540 * 541 * Returns the timespec64 representation of the nsec parameter. 542 */ 543 struct timespec64 ns_to_timespec64(const s64 nsec) 544 { 545 struct timespec64 ts; 546 s32 rem; 547 548 if (!nsec) 549 return (struct timespec64) {0, 0}; 550 551 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem); 552 if (unlikely(rem < 0)) { 553 ts.tv_sec--; 554 rem += NSEC_PER_SEC; 555 } 556 ts.tv_nsec = rem; 557 558 return ts; 559 } 560 EXPORT_SYMBOL(ns_to_timespec64); 561 562 /** 563 * msecs_to_jiffies: - convert milliseconds to jiffies 564 * @m: time in milliseconds 565 * 566 * conversion is done as follows: 567 * 568 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) 569 * 570 * - 'too large' values [that would result in larger than 571 * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. 572 * 573 * - all other values are converted to jiffies by either multiplying 574 * the input value by a factor or dividing it with a factor and 575 * handling any 32-bit overflows. 576 * for the details see __msecs_to_jiffies() 577 * 578 * msecs_to_jiffies() checks for the passed in value being a constant 579 * via __builtin_constant_p() allowing gcc to eliminate most of the 580 * code, __msecs_to_jiffies() is called if the value passed does not 581 * allow constant folding and the actual conversion must be done at 582 * runtime. 583 * the _msecs_to_jiffies helpers are the HZ dependent conversion 584 * routines found in include/linux/jiffies.h 585 */ 586 unsigned long __msecs_to_jiffies(const unsigned int m) 587 { 588 /* 589 * Negative value, means infinite timeout: 590 */ 591 if ((int)m < 0) 592 return MAX_JIFFY_OFFSET; 593 return _msecs_to_jiffies(m); 594 } 595 EXPORT_SYMBOL(__msecs_to_jiffies); 596 597 unsigned long __usecs_to_jiffies(const unsigned int u) 598 { 599 if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) 600 return MAX_JIFFY_OFFSET; 601 return _usecs_to_jiffies(u); 602 } 603 EXPORT_SYMBOL(__usecs_to_jiffies); 604 605 /* 606 * The TICK_NSEC - 1 rounds up the value to the next resolution. Note 607 * that a remainder subtract here would not do the right thing as the 608 * resolution values don't fall on second boundries. I.e. the line: 609 * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding. 610 * Note that due to the small error in the multiplier here, this 611 * rounding is incorrect for sufficiently large values of tv_nsec, but 612 * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're 613 * OK. 614 * 615 * Rather, we just shift the bits off the right. 616 * 617 * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec 618 * value to a scaled second value. 619 */ 620 static unsigned long 621 __timespec64_to_jiffies(u64 sec, long nsec) 622 { 623 nsec = nsec + TICK_NSEC - 1; 624 625 if (sec >= MAX_SEC_IN_JIFFIES){ 626 sec = MAX_SEC_IN_JIFFIES; 627 nsec = 0; 628 } 629 return ((sec * SEC_CONVERSION) + 630 (((u64)nsec * NSEC_CONVERSION) >> 631 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; 632 633 } 634 635 static unsigned long 636 __timespec_to_jiffies(unsigned long sec, long nsec) 637 { 638 return __timespec64_to_jiffies((u64)sec, nsec); 639 } 640 641 unsigned long 642 timespec64_to_jiffies(const struct timespec64 *value) 643 { 644 return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec); 645 } 646 EXPORT_SYMBOL(timespec64_to_jiffies); 647 648 void 649 jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value) 650 { 651 /* 652 * Convert jiffies to nanoseconds and separate with 653 * one divide. 654 */ 655 u32 rem; 656 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, 657 NSEC_PER_SEC, &rem); 658 value->tv_nsec = rem; 659 } 660 EXPORT_SYMBOL(jiffies_to_timespec64); 661 662 /* 663 * We could use a similar algorithm to timespec_to_jiffies (with a 664 * different multiplier for usec instead of nsec). But this has a 665 * problem with rounding: we can't exactly add TICK_NSEC - 1 to the 666 * usec value, since it's not necessarily integral. 667 * 668 * We could instead round in the intermediate scaled representation 669 * (i.e. in units of 1/2^(large scale) jiffies) but that's also 670 * perilous: the scaling introduces a small positive error, which 671 * combined with a division-rounding-upward (i.e. adding 2^(scale) - 1 672 * units to the intermediate before shifting) leads to accidental 673 * overflow and overestimates. 674 * 675 * At the cost of one additional multiplication by a constant, just 676 * use the timespec implementation. 677 */ 678 unsigned long 679 timeval_to_jiffies(const struct timeval *value) 680 { 681 return __timespec_to_jiffies(value->tv_sec, 682 value->tv_usec * NSEC_PER_USEC); 683 } 684 EXPORT_SYMBOL(timeval_to_jiffies); 685 686 void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value) 687 { 688 /* 689 * Convert jiffies to nanoseconds and separate with 690 * one divide. 691 */ 692 u32 rem; 693 694 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, 695 NSEC_PER_SEC, &rem); 696 value->tv_usec = rem / NSEC_PER_USEC; 697 } 698 EXPORT_SYMBOL(jiffies_to_timeval); 699 700 /* 701 * Convert jiffies/jiffies_64 to clock_t and back. 702 */ 703 clock_t jiffies_to_clock_t(unsigned long x) 704 { 705 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 706 # if HZ < USER_HZ 707 return x * (USER_HZ / HZ); 708 # else 709 return x / (HZ / USER_HZ); 710 # endif 711 #else 712 return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); 713 #endif 714 } 715 EXPORT_SYMBOL(jiffies_to_clock_t); 716 717 unsigned long clock_t_to_jiffies(unsigned long x) 718 { 719 #if (HZ % USER_HZ)==0 720 if (x >= ~0UL / (HZ / USER_HZ)) 721 return ~0UL; 722 return x * (HZ / USER_HZ); 723 #else 724 /* Don't worry about loss of precision here .. */ 725 if (x >= ~0UL / HZ * USER_HZ) 726 return ~0UL; 727 728 /* .. but do try to contain it here */ 729 return div_u64((u64)x * HZ, USER_HZ); 730 #endif 731 } 732 EXPORT_SYMBOL(clock_t_to_jiffies); 733 734 u64 jiffies_64_to_clock_t(u64 x) 735 { 736 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 737 # if HZ < USER_HZ 738 x = div_u64(x * USER_HZ, HZ); 739 # elif HZ > USER_HZ 740 x = div_u64(x, HZ / USER_HZ); 741 # else 742 /* Nothing to do */ 743 # endif 744 #else 745 /* 746 * There are better ways that don't overflow early, 747 * but even this doesn't overflow in hundreds of years 748 * in 64 bits, so.. 749 */ 750 x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ)); 751 #endif 752 return x; 753 } 754 EXPORT_SYMBOL(jiffies_64_to_clock_t); 755 756 u64 nsec_to_clock_t(u64 x) 757 { 758 #if (NSEC_PER_SEC % USER_HZ) == 0 759 return div_u64(x, NSEC_PER_SEC / USER_HZ); 760 #elif (USER_HZ % 512) == 0 761 return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512); 762 #else 763 /* 764 * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, 765 * overflow after 64.99 years. 766 * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... 767 */ 768 return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ); 769 #endif 770 } 771 772 u64 jiffies64_to_nsecs(u64 j) 773 { 774 #if !(NSEC_PER_SEC % HZ) 775 return (NSEC_PER_SEC / HZ) * j; 776 # else 777 return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN); 778 #endif 779 } 780 EXPORT_SYMBOL(jiffies64_to_nsecs); 781 782 /** 783 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64 784 * 785 * @n: nsecs in u64 786 * 787 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. 788 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed 789 * for scheduler, not for use in device drivers to calculate timeout value. 790 * 791 * note: 792 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 793 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 794 */ 795 u64 nsecs_to_jiffies64(u64 n) 796 { 797 #if (NSEC_PER_SEC % HZ) == 0 798 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */ 799 return div_u64(n, NSEC_PER_SEC / HZ); 800 #elif (HZ % 512) == 0 801 /* overflow after 292 years if HZ = 1024 */ 802 return div_u64(n * HZ / 512, NSEC_PER_SEC / 512); 803 #else 804 /* 805 * Generic case - optimized for cases where HZ is a multiple of 3. 806 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc. 807 */ 808 return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ); 809 #endif 810 } 811 EXPORT_SYMBOL(nsecs_to_jiffies64); 812 813 /** 814 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies 815 * 816 * @n: nsecs in u64 817 * 818 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. 819 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed 820 * for scheduler, not for use in device drivers to calculate timeout value. 821 * 822 * note: 823 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 824 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 825 */ 826 unsigned long nsecs_to_jiffies(u64 n) 827 { 828 return (unsigned long)nsecs_to_jiffies64(n); 829 } 830 EXPORT_SYMBOL_GPL(nsecs_to_jiffies); 831 832 /* 833 * Add two timespec64 values and do a safety check for overflow. 834 * It's assumed that both values are valid (>= 0). 835 * And, each timespec64 is in normalized form. 836 */ 837 struct timespec64 timespec64_add_safe(const struct timespec64 lhs, 838 const struct timespec64 rhs) 839 { 840 struct timespec64 res; 841 842 set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec, 843 lhs.tv_nsec + rhs.tv_nsec); 844 845 if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) { 846 res.tv_sec = TIME64_MAX; 847 res.tv_nsec = 0; 848 } 849 850 return res; 851 } 852 853 int get_timespec64(struct timespec64 *ts, 854 const struct __kernel_timespec __user *uts) 855 { 856 struct __kernel_timespec kts; 857 int ret; 858 859 ret = copy_from_user(&kts, uts, sizeof(kts)); 860 if (ret) 861 return -EFAULT; 862 863 ts->tv_sec = kts.tv_sec; 864 865 /* Zero out the padding for 32 bit systems or in compat mode */ 866 if (IS_ENABLED(CONFIG_64BIT_TIME) && (!IS_ENABLED(CONFIG_64BIT) || in_compat_syscall())) 867 kts.tv_nsec &= 0xFFFFFFFFUL; 868 869 ts->tv_nsec = kts.tv_nsec; 870 871 return 0; 872 } 873 EXPORT_SYMBOL_GPL(get_timespec64); 874 875 int put_timespec64(const struct timespec64 *ts, 876 struct __kernel_timespec __user *uts) 877 { 878 struct __kernel_timespec kts = { 879 .tv_sec = ts->tv_sec, 880 .tv_nsec = ts->tv_nsec 881 }; 882 883 return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0; 884 } 885 EXPORT_SYMBOL_GPL(put_timespec64); 886 887 int __compat_get_timespec64(struct timespec64 *ts64, 888 const struct compat_timespec __user *cts) 889 { 890 struct compat_timespec ts; 891 int ret; 892 893 ret = copy_from_user(&ts, cts, sizeof(ts)); 894 if (ret) 895 return -EFAULT; 896 897 ts64->tv_sec = ts.tv_sec; 898 ts64->tv_nsec = ts.tv_nsec; 899 900 return 0; 901 } 902 903 int __compat_put_timespec64(const struct timespec64 *ts64, 904 struct compat_timespec __user *cts) 905 { 906 struct compat_timespec ts = { 907 .tv_sec = ts64->tv_sec, 908 .tv_nsec = ts64->tv_nsec 909 }; 910 return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0; 911 } 912 913 int compat_get_timespec64(struct timespec64 *ts, const void __user *uts) 914 { 915 if (COMPAT_USE_64BIT_TIME) 916 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0; 917 else 918 return __compat_get_timespec64(ts, uts); 919 } 920 EXPORT_SYMBOL_GPL(compat_get_timespec64); 921 922 int compat_put_timespec64(const struct timespec64 *ts, void __user *uts) 923 { 924 if (COMPAT_USE_64BIT_TIME) 925 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0; 926 else 927 return __compat_put_timespec64(ts, uts); 928 } 929 EXPORT_SYMBOL_GPL(compat_put_timespec64); 930 931 int get_itimerspec64(struct itimerspec64 *it, 932 const struct __kernel_itimerspec __user *uit) 933 { 934 int ret; 935 936 ret = get_timespec64(&it->it_interval, &uit->it_interval); 937 if (ret) 938 return ret; 939 940 ret = get_timespec64(&it->it_value, &uit->it_value); 941 942 return ret; 943 } 944 EXPORT_SYMBOL_GPL(get_itimerspec64); 945 946 int put_itimerspec64(const struct itimerspec64 *it, 947 struct __kernel_itimerspec __user *uit) 948 { 949 int ret; 950 951 ret = put_timespec64(&it->it_interval, &uit->it_interval); 952 if (ret) 953 return ret; 954 955 ret = put_timespec64(&it->it_value, &uit->it_value); 956 957 return ret; 958 } 959 EXPORT_SYMBOL_GPL(put_itimerspec64); 960 961 int get_compat_itimerspec64(struct itimerspec64 *its, 962 const struct compat_itimerspec __user *uits) 963 { 964 965 if (__compat_get_timespec64(&its->it_interval, &uits->it_interval) || 966 __compat_get_timespec64(&its->it_value, &uits->it_value)) 967 return -EFAULT; 968 return 0; 969 } 970 EXPORT_SYMBOL_GPL(get_compat_itimerspec64); 971 972 int put_compat_itimerspec64(const struct itimerspec64 *its, 973 struct compat_itimerspec __user *uits) 974 { 975 if (__compat_put_timespec64(&its->it_interval, &uits->it_interval) || 976 __compat_put_timespec64(&its->it_value, &uits->it_value)) 977 return -EFAULT; 978 return 0; 979 } 980 EXPORT_SYMBOL_GPL(put_compat_itimerspec64); 981