1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 * 5 * This file contains the interface functions for the various time related 6 * system calls: time, stime, gettimeofday, settimeofday, adjtime 7 * 8 * Modification history: 9 * 10 * 1993-09-02 Philip Gladstone 11 * Created file with time related functions from sched/core.c and adjtimex() 12 * 1993-10-08 Torsten Duwe 13 * adjtime interface update and CMOS clock write code 14 * 1995-08-13 Torsten Duwe 15 * kernel PLL updated to 1994-12-13 specs (rfc-1589) 16 * 1999-01-16 Ulrich Windl 17 * Introduced error checking for many cases in adjtimex(). 18 * Updated NTP code according to technical memorandum Jan '96 19 * "A Kernel Model for Precision Timekeeping" by Dave Mills 20 * Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10) 21 * (Even though the technical memorandum forbids it) 22 * 2004-07-14 Christoph Lameter 23 * Added getnstimeofday to allow the posix timer functions to return 24 * with nanosecond accuracy 25 */ 26 27 #include <linux/export.h> 28 #include <linux/kernel.h> 29 #include <linux/timex.h> 30 #include <linux/capability.h> 31 #include <linux/timekeeper_internal.h> 32 #include <linux/errno.h> 33 #include <linux/syscalls.h> 34 #include <linux/security.h> 35 #include <linux/fs.h> 36 #include <linux/math64.h> 37 #include <linux/ptrace.h> 38 39 #include <linux/uaccess.h> 40 #include <linux/compat.h> 41 #include <asm/unistd.h> 42 43 #include <generated/timeconst.h> 44 #include "timekeeping.h" 45 46 /* 47 * The timezone where the local system is located. Used as a default by some 48 * programs who obtain this value by using gettimeofday. 49 */ 50 struct timezone sys_tz; 51 52 EXPORT_SYMBOL(sys_tz); 53 54 #ifdef __ARCH_WANT_SYS_TIME 55 56 /* 57 * sys_time() can be implemented in user-level using 58 * sys_gettimeofday(). Is this for backwards compatibility? If so, 59 * why not move it into the appropriate arch directory (for those 60 * architectures that need it). 61 */ 62 SYSCALL_DEFINE1(time, time_t __user *, tloc) 63 { 64 time_t i = (time_t)ktime_get_real_seconds(); 65 66 if (tloc) { 67 if (put_user(i,tloc)) 68 return -EFAULT; 69 } 70 force_successful_syscall_return(); 71 return i; 72 } 73 74 /* 75 * sys_stime() can be implemented in user-level using 76 * sys_settimeofday(). Is this for backwards compatibility? If so, 77 * why not move it into the appropriate arch directory (for those 78 * architectures that need it). 79 */ 80 81 SYSCALL_DEFINE1(stime, time_t __user *, tptr) 82 { 83 struct timespec64 tv; 84 int err; 85 86 if (get_user(tv.tv_sec, tptr)) 87 return -EFAULT; 88 89 tv.tv_nsec = 0; 90 91 err = security_settime64(&tv, NULL); 92 if (err) 93 return err; 94 95 do_settimeofday64(&tv); 96 return 0; 97 } 98 99 #endif /* __ARCH_WANT_SYS_TIME */ 100 101 #ifdef CONFIG_COMPAT 102 #ifdef __ARCH_WANT_COMPAT_SYS_TIME 103 104 /* old_time32_t is a 32 bit "long" and needs to get converted. */ 105 COMPAT_SYSCALL_DEFINE1(time, old_time32_t __user *, tloc) 106 { 107 old_time32_t i; 108 109 i = (old_time32_t)ktime_get_real_seconds(); 110 111 if (tloc) { 112 if (put_user(i,tloc)) 113 return -EFAULT; 114 } 115 force_successful_syscall_return(); 116 return i; 117 } 118 119 COMPAT_SYSCALL_DEFINE1(stime, old_time32_t __user *, tptr) 120 { 121 struct timespec64 tv; 122 int err; 123 124 if (get_user(tv.tv_sec, tptr)) 125 return -EFAULT; 126 127 tv.tv_nsec = 0; 128 129 err = security_settime64(&tv, NULL); 130 if (err) 131 return err; 132 133 do_settimeofday64(&tv); 134 return 0; 135 } 136 137 #endif /* __ARCH_WANT_COMPAT_SYS_TIME */ 138 #endif 139 140 SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv, 141 struct timezone __user *, tz) 142 { 143 if (likely(tv != NULL)) { 144 struct timespec64 ts; 145 146 ktime_get_real_ts64(&ts); 147 if (put_user(ts.tv_sec, &tv->tv_sec) || 148 put_user(ts.tv_nsec / 1000, &tv->tv_usec)) 149 return -EFAULT; 150 } 151 if (unlikely(tz != NULL)) { 152 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) 153 return -EFAULT; 154 } 155 return 0; 156 } 157 158 /* 159 * In case for some reason the CMOS clock has not already been running 160 * in UTC, but in some local time: The first time we set the timezone, 161 * we will warp the clock so that it is ticking UTC time instead of 162 * local time. Presumably, if someone is setting the timezone then we 163 * are running in an environment where the programs understand about 164 * timezones. This should be done at boot time in the /etc/rc script, 165 * as soon as possible, so that the clock can be set right. Otherwise, 166 * various programs will get confused when the clock gets warped. 167 */ 168 169 int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz) 170 { 171 static int firsttime = 1; 172 int error = 0; 173 174 if (tv && !timespec64_valid(tv)) 175 return -EINVAL; 176 177 error = security_settime64(tv, tz); 178 if (error) 179 return error; 180 181 if (tz) { 182 /* Verify we're witin the +-15 hrs range */ 183 if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60) 184 return -EINVAL; 185 186 sys_tz = *tz; 187 update_vsyscall_tz(); 188 if (firsttime) { 189 firsttime = 0; 190 if (!tv) 191 timekeeping_warp_clock(); 192 } 193 } 194 if (tv) 195 return do_settimeofday64(tv); 196 return 0; 197 } 198 199 SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, 200 struct timezone __user *, tz) 201 { 202 struct timespec64 new_ts; 203 struct timeval user_tv; 204 struct timezone new_tz; 205 206 if (tv) { 207 if (copy_from_user(&user_tv, tv, sizeof(*tv))) 208 return -EFAULT; 209 210 if (!timeval_valid(&user_tv)) 211 return -EINVAL; 212 213 new_ts.tv_sec = user_tv.tv_sec; 214 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; 215 } 216 if (tz) { 217 if (copy_from_user(&new_tz, tz, sizeof(*tz))) 218 return -EFAULT; 219 } 220 221 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL); 222 } 223 224 #ifdef CONFIG_COMPAT 225 COMPAT_SYSCALL_DEFINE2(gettimeofday, struct old_timeval32 __user *, tv, 226 struct timezone __user *, tz) 227 { 228 if (tv) { 229 struct timespec64 ts; 230 231 ktime_get_real_ts64(&ts); 232 if (put_user(ts.tv_sec, &tv->tv_sec) || 233 put_user(ts.tv_nsec / 1000, &tv->tv_usec)) 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 old_timeval32 __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 * mktime64 - Converts date to seconds. 347 * Converts Gregorian date to seconds since 1970-01-01 00:00:00. 348 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 349 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. 350 * 351 * [For the Julian calendar (which was used in Russia before 1917, 352 * Britain & colonies before 1752, anywhere else before 1582, 353 * and is still in use by some communities) leave out the 354 * -year/100+year/400 terms, and add 10.] 355 * 356 * This algorithm was first published by Gauss (I think). 357 * 358 * A leap second can be indicated by calling this function with sec as 359 * 60 (allowable under ISO 8601). The leap second is treated the same 360 * as the following second since they don't exist in UNIX time. 361 * 362 * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight 363 * tomorrow - (allowable under ISO 8601) is supported. 364 */ 365 time64_t mktime64(const unsigned int year0, const unsigned int mon0, 366 const unsigned int day, const unsigned int hour, 367 const unsigned int min, const unsigned int sec) 368 { 369 unsigned int mon = mon0, year = year0; 370 371 /* 1..12 -> 11,12,1..10 */ 372 if (0 >= (int) (mon -= 2)) { 373 mon += 12; /* Puts Feb last since it has leap day */ 374 year -= 1; 375 } 376 377 return ((((time64_t) 378 (year/4 - year/100 + year/400 + 367*mon/12 + day) + 379 year*365 - 719499 380 )*24 + hour /* now have hours - midnight tomorrow handled here */ 381 )*60 + min /* now have minutes */ 382 )*60 + sec; /* finally seconds */ 383 } 384 EXPORT_SYMBOL(mktime64); 385 386 /** 387 * set_normalized_timespec - set timespec sec and nsec parts and normalize 388 * 389 * @ts: pointer to timespec variable to be set 390 * @sec: seconds to set 391 * @nsec: nanoseconds to set 392 * 393 * Set seconds and nanoseconds field of a timespec variable and 394 * normalize to the timespec storage format 395 * 396 * Note: The tv_nsec part is always in the range of 397 * 0 <= tv_nsec < NSEC_PER_SEC 398 * For negative values only the tv_sec field is negative ! 399 */ 400 void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec) 401 { 402 while (nsec >= NSEC_PER_SEC) { 403 /* 404 * The following asm() prevents the compiler from 405 * optimising this loop into a modulo operation. See 406 * also __iter_div_u64_rem() in include/linux/time.h 407 */ 408 asm("" : "+rm"(nsec)); 409 nsec -= NSEC_PER_SEC; 410 ++sec; 411 } 412 while (nsec < 0) { 413 asm("" : "+rm"(nsec)); 414 nsec += NSEC_PER_SEC; 415 --sec; 416 } 417 ts->tv_sec = sec; 418 ts->tv_nsec = nsec; 419 } 420 EXPORT_SYMBOL(set_normalized_timespec); 421 422 /** 423 * ns_to_timespec - Convert nanoseconds to timespec 424 * @nsec: the nanoseconds value to be converted 425 * 426 * Returns the timespec representation of the nsec parameter. 427 */ 428 struct timespec ns_to_timespec(const s64 nsec) 429 { 430 struct timespec ts; 431 s32 rem; 432 433 if (!nsec) 434 return (struct timespec) {0, 0}; 435 436 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem); 437 if (unlikely(rem < 0)) { 438 ts.tv_sec--; 439 rem += NSEC_PER_SEC; 440 } 441 ts.tv_nsec = rem; 442 443 return ts; 444 } 445 EXPORT_SYMBOL(ns_to_timespec); 446 447 /** 448 * ns_to_timeval - Convert nanoseconds to timeval 449 * @nsec: the nanoseconds value to be converted 450 * 451 * Returns the timeval representation of the nsec parameter. 452 */ 453 struct timeval ns_to_timeval(const s64 nsec) 454 { 455 struct timespec ts = ns_to_timespec(nsec); 456 struct timeval tv; 457 458 tv.tv_sec = ts.tv_sec; 459 tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000; 460 461 return tv; 462 } 463 EXPORT_SYMBOL(ns_to_timeval); 464 465 struct __kernel_old_timeval ns_to_kernel_old_timeval(const s64 nsec) 466 { 467 struct timespec64 ts = ns_to_timespec64(nsec); 468 struct __kernel_old_timeval tv; 469 470 tv.tv_sec = ts.tv_sec; 471 tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000; 472 473 return tv; 474 } 475 EXPORT_SYMBOL(ns_to_kernel_old_timeval); 476 477 /** 478 * set_normalized_timespec - set timespec sec and nsec parts and normalize 479 * 480 * @ts: pointer to timespec variable to be set 481 * @sec: seconds to set 482 * @nsec: nanoseconds to set 483 * 484 * Set seconds and nanoseconds field of a timespec variable and 485 * normalize to the timespec storage format 486 * 487 * Note: The tv_nsec part is always in the range of 488 * 0 <= tv_nsec < NSEC_PER_SEC 489 * For negative values only the tv_sec field is negative ! 490 */ 491 void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec) 492 { 493 while (nsec >= NSEC_PER_SEC) { 494 /* 495 * The following asm() prevents the compiler from 496 * optimising this loop into a modulo operation. See 497 * also __iter_div_u64_rem() in include/linux/time.h 498 */ 499 asm("" : "+rm"(nsec)); 500 nsec -= NSEC_PER_SEC; 501 ++sec; 502 } 503 while (nsec < 0) { 504 asm("" : "+rm"(nsec)); 505 nsec += NSEC_PER_SEC; 506 --sec; 507 } 508 ts->tv_sec = sec; 509 ts->tv_nsec = nsec; 510 } 511 EXPORT_SYMBOL(set_normalized_timespec64); 512 513 /** 514 * ns_to_timespec64 - Convert nanoseconds to timespec64 515 * @nsec: the nanoseconds value to be converted 516 * 517 * Returns the timespec64 representation of the nsec parameter. 518 */ 519 struct timespec64 ns_to_timespec64(const s64 nsec) 520 { 521 struct timespec64 ts; 522 s32 rem; 523 524 if (!nsec) 525 return (struct timespec64) {0, 0}; 526 527 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem); 528 if (unlikely(rem < 0)) { 529 ts.tv_sec--; 530 rem += NSEC_PER_SEC; 531 } 532 ts.tv_nsec = rem; 533 534 return ts; 535 } 536 EXPORT_SYMBOL(ns_to_timespec64); 537 538 /** 539 * msecs_to_jiffies: - convert milliseconds to jiffies 540 * @m: time in milliseconds 541 * 542 * conversion is done as follows: 543 * 544 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) 545 * 546 * - 'too large' values [that would result in larger than 547 * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. 548 * 549 * - all other values are converted to jiffies by either multiplying 550 * the input value by a factor or dividing it with a factor and 551 * handling any 32-bit overflows. 552 * for the details see __msecs_to_jiffies() 553 * 554 * msecs_to_jiffies() checks for the passed in value being a constant 555 * via __builtin_constant_p() allowing gcc to eliminate most of the 556 * code, __msecs_to_jiffies() is called if the value passed does not 557 * allow constant folding and the actual conversion must be done at 558 * runtime. 559 * the _msecs_to_jiffies helpers are the HZ dependent conversion 560 * routines found in include/linux/jiffies.h 561 */ 562 unsigned long __msecs_to_jiffies(const unsigned int m) 563 { 564 /* 565 * Negative value, means infinite timeout: 566 */ 567 if ((int)m < 0) 568 return MAX_JIFFY_OFFSET; 569 return _msecs_to_jiffies(m); 570 } 571 EXPORT_SYMBOL(__msecs_to_jiffies); 572 573 unsigned long __usecs_to_jiffies(const unsigned int u) 574 { 575 if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) 576 return MAX_JIFFY_OFFSET; 577 return _usecs_to_jiffies(u); 578 } 579 EXPORT_SYMBOL(__usecs_to_jiffies); 580 581 /* 582 * The TICK_NSEC - 1 rounds up the value to the next resolution. Note 583 * that a remainder subtract here would not do the right thing as the 584 * resolution values don't fall on second boundries. I.e. the line: 585 * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding. 586 * Note that due to the small error in the multiplier here, this 587 * rounding is incorrect for sufficiently large values of tv_nsec, but 588 * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're 589 * OK. 590 * 591 * Rather, we just shift the bits off the right. 592 * 593 * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec 594 * value to a scaled second value. 595 */ 596 static unsigned long 597 __timespec64_to_jiffies(u64 sec, long nsec) 598 { 599 nsec = nsec + TICK_NSEC - 1; 600 601 if (sec >= MAX_SEC_IN_JIFFIES){ 602 sec = MAX_SEC_IN_JIFFIES; 603 nsec = 0; 604 } 605 return ((sec * SEC_CONVERSION) + 606 (((u64)nsec * NSEC_CONVERSION) >> 607 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; 608 609 } 610 611 static unsigned long 612 __timespec_to_jiffies(unsigned long sec, long nsec) 613 { 614 return __timespec64_to_jiffies((u64)sec, nsec); 615 } 616 617 unsigned long 618 timespec64_to_jiffies(const struct timespec64 *value) 619 { 620 return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec); 621 } 622 EXPORT_SYMBOL(timespec64_to_jiffies); 623 624 void 625 jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value) 626 { 627 /* 628 * Convert jiffies to nanoseconds and separate with 629 * one divide. 630 */ 631 u32 rem; 632 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, 633 NSEC_PER_SEC, &rem); 634 value->tv_nsec = rem; 635 } 636 EXPORT_SYMBOL(jiffies_to_timespec64); 637 638 /* 639 * We could use a similar algorithm to timespec_to_jiffies (with a 640 * different multiplier for usec instead of nsec). But this has a 641 * problem with rounding: we can't exactly add TICK_NSEC - 1 to the 642 * usec value, since it's not necessarily integral. 643 * 644 * We could instead round in the intermediate scaled representation 645 * (i.e. in units of 1/2^(large scale) jiffies) but that's also 646 * perilous: the scaling introduces a small positive error, which 647 * combined with a division-rounding-upward (i.e. adding 2^(scale) - 1 648 * units to the intermediate before shifting) leads to accidental 649 * overflow and overestimates. 650 * 651 * At the cost of one additional multiplication by a constant, just 652 * use the timespec implementation. 653 */ 654 unsigned long 655 timeval_to_jiffies(const struct timeval *value) 656 { 657 return __timespec_to_jiffies(value->tv_sec, 658 value->tv_usec * NSEC_PER_USEC); 659 } 660 EXPORT_SYMBOL(timeval_to_jiffies); 661 662 void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value) 663 { 664 /* 665 * Convert jiffies to nanoseconds and separate with 666 * one divide. 667 */ 668 u32 rem; 669 670 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, 671 NSEC_PER_SEC, &rem); 672 value->tv_usec = rem / NSEC_PER_USEC; 673 } 674 EXPORT_SYMBOL(jiffies_to_timeval); 675 676 /* 677 * Convert jiffies/jiffies_64 to clock_t and back. 678 */ 679 clock_t jiffies_to_clock_t(unsigned long x) 680 { 681 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 682 # if HZ < USER_HZ 683 return x * (USER_HZ / HZ); 684 # else 685 return x / (HZ / USER_HZ); 686 # endif 687 #else 688 return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); 689 #endif 690 } 691 EXPORT_SYMBOL(jiffies_to_clock_t); 692 693 unsigned long clock_t_to_jiffies(unsigned long x) 694 { 695 #if (HZ % USER_HZ)==0 696 if (x >= ~0UL / (HZ / USER_HZ)) 697 return ~0UL; 698 return x * (HZ / USER_HZ); 699 #else 700 /* Don't worry about loss of precision here .. */ 701 if (x >= ~0UL / HZ * USER_HZ) 702 return ~0UL; 703 704 /* .. but do try to contain it here */ 705 return div_u64((u64)x * HZ, USER_HZ); 706 #endif 707 } 708 EXPORT_SYMBOL(clock_t_to_jiffies); 709 710 u64 jiffies_64_to_clock_t(u64 x) 711 { 712 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 713 # if HZ < USER_HZ 714 x = div_u64(x * USER_HZ, HZ); 715 # elif HZ > USER_HZ 716 x = div_u64(x, HZ / USER_HZ); 717 # else 718 /* Nothing to do */ 719 # endif 720 #else 721 /* 722 * There are better ways that don't overflow early, 723 * but even this doesn't overflow in hundreds of years 724 * in 64 bits, so.. 725 */ 726 x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ)); 727 #endif 728 return x; 729 } 730 EXPORT_SYMBOL(jiffies_64_to_clock_t); 731 732 u64 nsec_to_clock_t(u64 x) 733 { 734 #if (NSEC_PER_SEC % USER_HZ) == 0 735 return div_u64(x, NSEC_PER_SEC / USER_HZ); 736 #elif (USER_HZ % 512) == 0 737 return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512); 738 #else 739 /* 740 * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, 741 * overflow after 64.99 years. 742 * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... 743 */ 744 return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ); 745 #endif 746 } 747 748 u64 jiffies64_to_nsecs(u64 j) 749 { 750 #if !(NSEC_PER_SEC % HZ) 751 return (NSEC_PER_SEC / HZ) * j; 752 # else 753 return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN); 754 #endif 755 } 756 EXPORT_SYMBOL(jiffies64_to_nsecs); 757 758 /** 759 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64 760 * 761 * @n: nsecs in u64 762 * 763 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. 764 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed 765 * for scheduler, not for use in device drivers to calculate timeout value. 766 * 767 * note: 768 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 769 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 770 */ 771 u64 nsecs_to_jiffies64(u64 n) 772 { 773 #if (NSEC_PER_SEC % HZ) == 0 774 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */ 775 return div_u64(n, NSEC_PER_SEC / HZ); 776 #elif (HZ % 512) == 0 777 /* overflow after 292 years if HZ = 1024 */ 778 return div_u64(n * HZ / 512, NSEC_PER_SEC / 512); 779 #else 780 /* 781 * Generic case - optimized for cases where HZ is a multiple of 3. 782 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc. 783 */ 784 return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ); 785 #endif 786 } 787 EXPORT_SYMBOL(nsecs_to_jiffies64); 788 789 /** 790 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies 791 * 792 * @n: nsecs in u64 793 * 794 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. 795 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed 796 * for scheduler, not for use in device drivers to calculate timeout value. 797 * 798 * note: 799 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 800 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 801 */ 802 unsigned long nsecs_to_jiffies(u64 n) 803 { 804 return (unsigned long)nsecs_to_jiffies64(n); 805 } 806 EXPORT_SYMBOL_GPL(nsecs_to_jiffies); 807 808 /* 809 * Add two timespec64 values and do a safety check for overflow. 810 * It's assumed that both values are valid (>= 0). 811 * And, each timespec64 is in normalized form. 812 */ 813 struct timespec64 timespec64_add_safe(const struct timespec64 lhs, 814 const struct timespec64 rhs) 815 { 816 struct timespec64 res; 817 818 set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec, 819 lhs.tv_nsec + rhs.tv_nsec); 820 821 if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) { 822 res.tv_sec = TIME64_MAX; 823 res.tv_nsec = 0; 824 } 825 826 return res; 827 } 828 829 int get_timespec64(struct timespec64 *ts, 830 const struct __kernel_timespec __user *uts) 831 { 832 struct __kernel_timespec kts; 833 int ret; 834 835 ret = copy_from_user(&kts, uts, sizeof(kts)); 836 if (ret) 837 return -EFAULT; 838 839 ts->tv_sec = kts.tv_sec; 840 841 /* Zero out the padding for 32 bit systems or in compat mode */ 842 if (IS_ENABLED(CONFIG_64BIT_TIME) && in_compat_syscall()) 843 kts.tv_nsec &= 0xFFFFFFFFUL; 844 845 ts->tv_nsec = kts.tv_nsec; 846 847 return 0; 848 } 849 EXPORT_SYMBOL_GPL(get_timespec64); 850 851 int put_timespec64(const struct timespec64 *ts, 852 struct __kernel_timespec __user *uts) 853 { 854 struct __kernel_timespec kts = { 855 .tv_sec = ts->tv_sec, 856 .tv_nsec = ts->tv_nsec 857 }; 858 859 return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0; 860 } 861 EXPORT_SYMBOL_GPL(put_timespec64); 862 863 static int __get_old_timespec32(struct timespec64 *ts64, 864 const struct old_timespec32 __user *cts) 865 { 866 struct old_timespec32 ts; 867 int ret; 868 869 ret = copy_from_user(&ts, cts, sizeof(ts)); 870 if (ret) 871 return -EFAULT; 872 873 ts64->tv_sec = ts.tv_sec; 874 ts64->tv_nsec = ts.tv_nsec; 875 876 return 0; 877 } 878 879 static int __put_old_timespec32(const struct timespec64 *ts64, 880 struct old_timespec32 __user *cts) 881 { 882 struct old_timespec32 ts = { 883 .tv_sec = ts64->tv_sec, 884 .tv_nsec = ts64->tv_nsec 885 }; 886 return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0; 887 } 888 889 int get_old_timespec32(struct timespec64 *ts, const void __user *uts) 890 { 891 if (COMPAT_USE_64BIT_TIME) 892 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0; 893 else 894 return __get_old_timespec32(ts, uts); 895 } 896 EXPORT_SYMBOL_GPL(get_old_timespec32); 897 898 int put_old_timespec32(const struct timespec64 *ts, void __user *uts) 899 { 900 if (COMPAT_USE_64BIT_TIME) 901 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0; 902 else 903 return __put_old_timespec32(ts, uts); 904 } 905 EXPORT_SYMBOL_GPL(put_old_timespec32); 906 907 int get_itimerspec64(struct itimerspec64 *it, 908 const struct __kernel_itimerspec __user *uit) 909 { 910 int ret; 911 912 ret = get_timespec64(&it->it_interval, &uit->it_interval); 913 if (ret) 914 return ret; 915 916 ret = get_timespec64(&it->it_value, &uit->it_value); 917 918 return ret; 919 } 920 EXPORT_SYMBOL_GPL(get_itimerspec64); 921 922 int put_itimerspec64(const struct itimerspec64 *it, 923 struct __kernel_itimerspec __user *uit) 924 { 925 int ret; 926 927 ret = put_timespec64(&it->it_interval, &uit->it_interval); 928 if (ret) 929 return ret; 930 931 ret = put_timespec64(&it->it_value, &uit->it_value); 932 933 return ret; 934 } 935 EXPORT_SYMBOL_GPL(put_itimerspec64); 936 937 int get_old_itimerspec32(struct itimerspec64 *its, 938 const struct old_itimerspec32 __user *uits) 939 { 940 941 if (__get_old_timespec32(&its->it_interval, &uits->it_interval) || 942 __get_old_timespec32(&its->it_value, &uits->it_value)) 943 return -EFAULT; 944 return 0; 945 } 946 EXPORT_SYMBOL_GPL(get_old_itimerspec32); 947 948 int put_old_itimerspec32(const struct itimerspec64 *its, 949 struct old_itimerspec32 __user *uits) 950 { 951 if (__put_old_timespec32(&its->it_interval, &uits->it_interval) || 952 __put_old_timespec32(&its->it_value, &uits->it_value)) 953 return -EFAULT; 954 return 0; 955 } 956 EXPORT_SYMBOL_GPL(put_old_itimerspec32); 957