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, __kernel_old_time_t __user *, tloc) 63 { 64 __kernel_old_time_t i = (__kernel_old_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, __kernel_old_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_32BIT_TIME 102 #ifdef __ARCH_WANT_SYS_TIME32 103 104 /* old_time32_t is a 32 bit "long" and needs to get converted. */ 105 SYSCALL_DEFINE1(time32, 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 SYSCALL_DEFINE1(stime32, 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_SYS_TIME32 */ 138 #endif 139 140 SYSCALL_DEFINE2(gettimeofday, struct __kernel_old_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_settod(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 within 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 __kernel_old_timeval __user *, tv, 200 struct timezone __user *, tz) 201 { 202 struct timespec64 new_ts; 203 struct timezone new_tz; 204 205 if (tv) { 206 if (get_user(new_ts.tv_sec, &tv->tv_sec) || 207 get_user(new_ts.tv_nsec, &tv->tv_usec)) 208 return -EFAULT; 209 210 if (new_ts.tv_nsec > USEC_PER_SEC || new_ts.tv_nsec < 0) 211 return -EINVAL; 212 213 new_ts.tv_nsec *= NSEC_PER_USEC; 214 } 215 if (tz) { 216 if (copy_from_user(&new_tz, tz, sizeof(*tz))) 217 return -EFAULT; 218 } 219 220 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL); 221 } 222 223 #ifdef CONFIG_COMPAT 224 COMPAT_SYSCALL_DEFINE2(gettimeofday, struct old_timeval32 __user *, tv, 225 struct timezone __user *, tz) 226 { 227 if (tv) { 228 struct timespec64 ts; 229 230 ktime_get_real_ts64(&ts); 231 if (put_user(ts.tv_sec, &tv->tv_sec) || 232 put_user(ts.tv_nsec / 1000, &tv->tv_usec)) 233 return -EFAULT; 234 } 235 if (tz) { 236 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) 237 return -EFAULT; 238 } 239 240 return 0; 241 } 242 243 COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv, 244 struct timezone __user *, tz) 245 { 246 struct timespec64 new_ts; 247 struct timezone new_tz; 248 249 if (tv) { 250 if (get_user(new_ts.tv_sec, &tv->tv_sec) || 251 get_user(new_ts.tv_nsec, &tv->tv_usec)) 252 return -EFAULT; 253 254 if (new_ts.tv_nsec > USEC_PER_SEC || new_ts.tv_nsec < 0) 255 return -EINVAL; 256 257 new_ts.tv_nsec *= NSEC_PER_USEC; 258 } 259 if (tz) { 260 if (copy_from_user(&new_tz, tz, sizeof(*tz))) 261 return -EFAULT; 262 } 263 264 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL); 265 } 266 #endif 267 268 #ifdef CONFIG_64BIT 269 SYSCALL_DEFINE1(adjtimex, struct __kernel_timex __user *, txc_p) 270 { 271 struct __kernel_timex txc; /* Local copy of parameter */ 272 int ret; 273 274 /* Copy the user data space into the kernel copy 275 * structure. But bear in mind that the structures 276 * may change 277 */ 278 if (copy_from_user(&txc, txc_p, sizeof(struct __kernel_timex))) 279 return -EFAULT; 280 ret = do_adjtimex(&txc); 281 return copy_to_user(txc_p, &txc, sizeof(struct __kernel_timex)) ? -EFAULT : ret; 282 } 283 #endif 284 285 #ifdef CONFIG_COMPAT_32BIT_TIME 286 int get_old_timex32(struct __kernel_timex *txc, const struct old_timex32 __user *utp) 287 { 288 struct old_timex32 tx32; 289 290 memset(txc, 0, sizeof(struct __kernel_timex)); 291 if (copy_from_user(&tx32, utp, sizeof(struct old_timex32))) 292 return -EFAULT; 293 294 txc->modes = tx32.modes; 295 txc->offset = tx32.offset; 296 txc->freq = tx32.freq; 297 txc->maxerror = tx32.maxerror; 298 txc->esterror = tx32.esterror; 299 txc->status = tx32.status; 300 txc->constant = tx32.constant; 301 txc->precision = tx32.precision; 302 txc->tolerance = tx32.tolerance; 303 txc->time.tv_sec = tx32.time.tv_sec; 304 txc->time.tv_usec = tx32.time.tv_usec; 305 txc->tick = tx32.tick; 306 txc->ppsfreq = tx32.ppsfreq; 307 txc->jitter = tx32.jitter; 308 txc->shift = tx32.shift; 309 txc->stabil = tx32.stabil; 310 txc->jitcnt = tx32.jitcnt; 311 txc->calcnt = tx32.calcnt; 312 txc->errcnt = tx32.errcnt; 313 txc->stbcnt = tx32.stbcnt; 314 315 return 0; 316 } 317 318 int put_old_timex32(struct old_timex32 __user *utp, const struct __kernel_timex *txc) 319 { 320 struct old_timex32 tx32; 321 322 memset(&tx32, 0, sizeof(struct old_timex32)); 323 tx32.modes = txc->modes; 324 tx32.offset = txc->offset; 325 tx32.freq = txc->freq; 326 tx32.maxerror = txc->maxerror; 327 tx32.esterror = txc->esterror; 328 tx32.status = txc->status; 329 tx32.constant = txc->constant; 330 tx32.precision = txc->precision; 331 tx32.tolerance = txc->tolerance; 332 tx32.time.tv_sec = txc->time.tv_sec; 333 tx32.time.tv_usec = txc->time.tv_usec; 334 tx32.tick = txc->tick; 335 tx32.ppsfreq = txc->ppsfreq; 336 tx32.jitter = txc->jitter; 337 tx32.shift = txc->shift; 338 tx32.stabil = txc->stabil; 339 tx32.jitcnt = txc->jitcnt; 340 tx32.calcnt = txc->calcnt; 341 tx32.errcnt = txc->errcnt; 342 tx32.stbcnt = txc->stbcnt; 343 tx32.tai = txc->tai; 344 if (copy_to_user(utp, &tx32, sizeof(struct old_timex32))) 345 return -EFAULT; 346 return 0; 347 } 348 349 SYSCALL_DEFINE1(adjtimex_time32, struct old_timex32 __user *, utp) 350 { 351 struct __kernel_timex txc; 352 int err, ret; 353 354 err = get_old_timex32(&txc, utp); 355 if (err) 356 return err; 357 358 ret = do_adjtimex(&txc); 359 360 err = put_old_timex32(utp, &txc); 361 if (err) 362 return err; 363 364 return ret; 365 } 366 #endif 367 368 /** 369 * jiffies_to_msecs - Convert jiffies to milliseconds 370 * @j: jiffies value 371 * 372 * Avoid unnecessary multiplications/divisions in the 373 * two most common HZ cases. 374 * 375 * Return: milliseconds value 376 */ 377 unsigned int jiffies_to_msecs(const unsigned long j) 378 { 379 #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) 380 return (MSEC_PER_SEC / HZ) * j; 381 #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) 382 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); 383 #else 384 # if BITS_PER_LONG == 32 385 return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >> 386 HZ_TO_MSEC_SHR32; 387 # else 388 return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN); 389 # endif 390 #endif 391 } 392 EXPORT_SYMBOL(jiffies_to_msecs); 393 394 /** 395 * jiffies_to_usecs - Convert jiffies to microseconds 396 * @j: jiffies value 397 * 398 * Return: microseconds value 399 */ 400 unsigned int jiffies_to_usecs(const unsigned long j) 401 { 402 /* 403 * Hz usually doesn't go much further MSEC_PER_SEC. 404 * jiffies_to_usecs() and usecs_to_jiffies() depend on that. 405 */ 406 BUILD_BUG_ON(HZ > USEC_PER_SEC); 407 408 #if !(USEC_PER_SEC % HZ) 409 return (USEC_PER_SEC / HZ) * j; 410 #else 411 # if BITS_PER_LONG == 32 412 return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32; 413 # else 414 return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN; 415 # endif 416 #endif 417 } 418 EXPORT_SYMBOL(jiffies_to_usecs); 419 420 /** 421 * mktime64 - Converts date to seconds. 422 * @year0: year to convert 423 * @mon0: month to convert 424 * @day: day to convert 425 * @hour: hour to convert 426 * @min: minute to convert 427 * @sec: second to convert 428 * 429 * Converts Gregorian date to seconds since 1970-01-01 00:00:00. 430 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 431 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. 432 * 433 * [For the Julian calendar (which was used in Russia before 1917, 434 * Britain & colonies before 1752, anywhere else before 1582, 435 * and is still in use by some communities) leave out the 436 * -year/100+year/400 terms, and add 10.] 437 * 438 * This algorithm was first published by Gauss (I think). 439 * 440 * A leap second can be indicated by calling this function with sec as 441 * 60 (allowable under ISO 8601). The leap second is treated the same 442 * as the following second since they don't exist in UNIX time. 443 * 444 * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight 445 * tomorrow - (allowable under ISO 8601) is supported. 446 * 447 * Return: seconds since the epoch time for the given input date 448 */ 449 time64_t mktime64(const unsigned int year0, const unsigned int mon0, 450 const unsigned int day, const unsigned int hour, 451 const unsigned int min, const unsigned int sec) 452 { 453 unsigned int mon = mon0, year = year0; 454 455 /* 1..12 -> 11,12,1..10 */ 456 if (0 >= (int) (mon -= 2)) { 457 mon += 12; /* Puts Feb last since it has leap day */ 458 year -= 1; 459 } 460 461 return ((((time64_t) 462 (year/4 - year/100 + year/400 + 367*mon/12 + day) + 463 year*365 - 719499 464 )*24 + hour /* now have hours - midnight tomorrow handled here */ 465 )*60 + min /* now have minutes */ 466 )*60 + sec; /* finally seconds */ 467 } 468 EXPORT_SYMBOL(mktime64); 469 470 struct __kernel_old_timeval ns_to_kernel_old_timeval(s64 nsec) 471 { 472 struct timespec64 ts = ns_to_timespec64(nsec); 473 struct __kernel_old_timeval tv; 474 475 tv.tv_sec = ts.tv_sec; 476 tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000; 477 478 return tv; 479 } 480 EXPORT_SYMBOL(ns_to_kernel_old_timeval); 481 482 /** 483 * set_normalized_timespec64 - set timespec sec and nsec parts and normalize 484 * 485 * @ts: pointer to timespec variable to be set 486 * @sec: seconds to set 487 * @nsec: nanoseconds to set 488 * 489 * Set seconds and nanoseconds field of a timespec variable and 490 * normalize to the timespec storage format 491 * 492 * Note: The tv_nsec part is always in the range of 0 <= tv_nsec < NSEC_PER_SEC. 493 * For negative values only the tv_sec field is negative ! 494 */ 495 void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec) 496 { 497 while (nsec >= NSEC_PER_SEC) { 498 /* 499 * The following asm() prevents the compiler from 500 * optimising this loop into a modulo operation. See 501 * also __iter_div_u64_rem() in include/linux/time.h 502 */ 503 asm("" : "+rm"(nsec)); 504 nsec -= NSEC_PER_SEC; 505 ++sec; 506 } 507 while (nsec < 0) { 508 asm("" : "+rm"(nsec)); 509 nsec += NSEC_PER_SEC; 510 --sec; 511 } 512 ts->tv_sec = sec; 513 ts->tv_nsec = nsec; 514 } 515 EXPORT_SYMBOL(set_normalized_timespec64); 516 517 /** 518 * ns_to_timespec64 - Convert nanoseconds to timespec64 519 * @nsec: the nanoseconds value to be converted 520 * 521 * Return: the timespec64 representation of the nsec parameter. 522 */ 523 struct timespec64 ns_to_timespec64(s64 nsec) 524 { 525 struct timespec64 ts = { 0, 0 }; 526 s32 rem; 527 528 if (likely(nsec > 0)) { 529 ts.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem); 530 ts.tv_nsec = rem; 531 } else if (nsec < 0) { 532 /* 533 * With negative times, tv_sec points to the earlier 534 * second, and tv_nsec counts the nanoseconds since 535 * then, so tv_nsec is always a positive number. 536 */ 537 ts.tv_sec = -div_u64_rem(-nsec - 1, NSEC_PER_SEC, &rem) - 1; 538 ts.tv_nsec = NSEC_PER_SEC - rem - 1; 539 } 540 541 return ts; 542 } 543 EXPORT_SYMBOL(ns_to_timespec64); 544 545 /** 546 * __msecs_to_jiffies: - convert milliseconds to jiffies 547 * @m: time in milliseconds 548 * 549 * conversion is done as follows: 550 * 551 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) 552 * 553 * - 'too large' values [that would result in larger than 554 * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. 555 * 556 * - all other values are converted to jiffies by either multiplying 557 * the input value by a factor or dividing it with a factor and 558 * handling any 32-bit overflows. 559 * for the details see __msecs_to_jiffies() 560 * 561 * __msecs_to_jiffies() checks for the passed in value being a constant 562 * via __builtin_constant_p() allowing gcc to eliminate most of the 563 * code, __msecs_to_jiffies() is called if the value passed does not 564 * allow constant folding and the actual conversion must be done at 565 * runtime. 566 * The _msecs_to_jiffies helpers are the HZ dependent conversion 567 * routines found in include/linux/jiffies.h 568 * 569 * Return: jiffies value 570 */ 571 unsigned long __msecs_to_jiffies(const unsigned int m) 572 { 573 /* 574 * Negative value, means infinite timeout: 575 */ 576 if ((int)m < 0) 577 return MAX_JIFFY_OFFSET; 578 return _msecs_to_jiffies(m); 579 } 580 EXPORT_SYMBOL(__msecs_to_jiffies); 581 582 /** 583 * __usecs_to_jiffies: - convert microseconds to jiffies 584 * @u: time in milliseconds 585 * 586 * Return: jiffies value 587 */ 588 unsigned long __usecs_to_jiffies(const unsigned int u) 589 { 590 if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) 591 return MAX_JIFFY_OFFSET; 592 return _usecs_to_jiffies(u); 593 } 594 EXPORT_SYMBOL(__usecs_to_jiffies); 595 596 /** 597 * timespec64_to_jiffies - convert a timespec64 value to jiffies 598 * @value: pointer to &struct timespec64 599 * 600 * The TICK_NSEC - 1 rounds up the value to the next resolution. Note 601 * that a remainder subtract here would not do the right thing as the 602 * resolution values don't fall on second boundaries. I.e. the line: 603 * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding. 604 * Note that due to the small error in the multiplier here, this 605 * rounding is incorrect for sufficiently large values of tv_nsec, but 606 * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're 607 * OK. 608 * 609 * Rather, we just shift the bits off the right. 610 * 611 * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec 612 * value to a scaled second value. 613 * 614 * Return: jiffies value 615 */ 616 unsigned long 617 timespec64_to_jiffies(const struct timespec64 *value) 618 { 619 u64 sec = value->tv_sec; 620 long nsec = value->tv_nsec + TICK_NSEC - 1; 621 622 if (sec >= MAX_SEC_IN_JIFFIES){ 623 sec = MAX_SEC_IN_JIFFIES; 624 nsec = 0; 625 } 626 return ((sec * SEC_CONVERSION) + 627 (((u64)nsec * NSEC_CONVERSION) >> 628 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; 629 630 } 631 EXPORT_SYMBOL(timespec64_to_jiffies); 632 633 /** 634 * jiffies_to_timespec64 - convert jiffies value to &struct timespec64 635 * @jiffies: jiffies value 636 * @value: pointer to &struct timespec64 637 */ 638 void 639 jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value) 640 { 641 /* 642 * Convert jiffies to nanoseconds and separate with 643 * one divide. 644 */ 645 u32 rem; 646 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, 647 NSEC_PER_SEC, &rem); 648 value->tv_nsec = rem; 649 } 650 EXPORT_SYMBOL(jiffies_to_timespec64); 651 652 /* 653 * Convert jiffies/jiffies_64 to clock_t and back. 654 */ 655 656 /** 657 * jiffies_to_clock_t - Convert jiffies to clock_t 658 * @x: jiffies value 659 * 660 * Return: jiffies converted to clock_t (CLOCKS_PER_SEC) 661 */ 662 clock_t jiffies_to_clock_t(unsigned long x) 663 { 664 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 665 # if HZ < USER_HZ 666 return x * (USER_HZ / HZ); 667 # else 668 return x / (HZ / USER_HZ); 669 # endif 670 #else 671 return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); 672 #endif 673 } 674 EXPORT_SYMBOL(jiffies_to_clock_t); 675 676 /** 677 * clock_t_to_jiffies - Convert clock_t to jiffies 678 * @x: clock_t value 679 * 680 * Return: clock_t value converted to jiffies 681 */ 682 unsigned long clock_t_to_jiffies(unsigned long x) 683 { 684 #if (HZ % USER_HZ)==0 685 if (x >= ~0UL / (HZ / USER_HZ)) 686 return ~0UL; 687 return x * (HZ / USER_HZ); 688 #else 689 /* Don't worry about loss of precision here .. */ 690 if (x >= ~0UL / HZ * USER_HZ) 691 return ~0UL; 692 693 /* .. but do try to contain it here */ 694 return div_u64((u64)x * HZ, USER_HZ); 695 #endif 696 } 697 EXPORT_SYMBOL(clock_t_to_jiffies); 698 699 /** 700 * jiffies_64_to_clock_t - Convert jiffies_64 to clock_t 701 * @x: jiffies_64 value 702 * 703 * Return: jiffies_64 value converted to 64-bit "clock_t" (CLOCKS_PER_SEC) 704 */ 705 u64 jiffies_64_to_clock_t(u64 x) 706 { 707 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 708 # if HZ < USER_HZ 709 x = div_u64(x * USER_HZ, HZ); 710 # elif HZ > USER_HZ 711 x = div_u64(x, HZ / USER_HZ); 712 # else 713 /* Nothing to do */ 714 # endif 715 #else 716 /* 717 * There are better ways that don't overflow early, 718 * but even this doesn't overflow in hundreds of years 719 * in 64 bits, so.. 720 */ 721 x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ)); 722 #endif 723 return x; 724 } 725 EXPORT_SYMBOL(jiffies_64_to_clock_t); 726 727 /** 728 * nsec_to_clock_t - Convert nsec value to clock_t 729 * @x: nsec value 730 * 731 * Return: nsec value converted to 64-bit "clock_t" (CLOCKS_PER_SEC) 732 */ 733 u64 nsec_to_clock_t(u64 x) 734 { 735 #if (NSEC_PER_SEC % USER_HZ) == 0 736 return div_u64(x, NSEC_PER_SEC / USER_HZ); 737 #elif (USER_HZ % 512) == 0 738 return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512); 739 #else 740 /* 741 * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, 742 * overflow after 64.99 years. 743 * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... 744 */ 745 return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ); 746 #endif 747 } 748 749 /** 750 * jiffies64_to_nsecs - Convert jiffies64 to nanoseconds 751 * @j: jiffies64 value 752 * 753 * Return: nanoseconds value 754 */ 755 u64 jiffies64_to_nsecs(u64 j) 756 { 757 #if !(NSEC_PER_SEC % HZ) 758 return (NSEC_PER_SEC / HZ) * j; 759 # else 760 return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN); 761 #endif 762 } 763 EXPORT_SYMBOL(jiffies64_to_nsecs); 764 765 /** 766 * jiffies64_to_msecs - Convert jiffies64 to milliseconds 767 * @j: jiffies64 value 768 * 769 * Return: milliseconds value 770 */ 771 u64 jiffies64_to_msecs(const u64 j) 772 { 773 #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) 774 return (MSEC_PER_SEC / HZ) * j; 775 #else 776 return div_u64(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN); 777 #endif 778 } 779 EXPORT_SYMBOL(jiffies64_to_msecs); 780 781 /** 782 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64 783 * 784 * @n: nsecs in u64 785 * 786 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. 787 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed 788 * for scheduler, not for use in device drivers to calculate timeout value. 789 * 790 * note: 791 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 792 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 793 * 794 * Return: nsecs converted to jiffies64 value 795 */ 796 u64 nsecs_to_jiffies64(u64 n) 797 { 798 #if (NSEC_PER_SEC % HZ) == 0 799 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */ 800 return div_u64(n, NSEC_PER_SEC / HZ); 801 #elif (HZ % 512) == 0 802 /* overflow after 292 years if HZ = 1024 */ 803 return div_u64(n * HZ / 512, NSEC_PER_SEC / 512); 804 #else 805 /* 806 * Generic case - optimized for cases where HZ is a multiple of 3. 807 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc. 808 */ 809 return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ); 810 #endif 811 } 812 EXPORT_SYMBOL(nsecs_to_jiffies64); 813 814 /** 815 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies 816 * 817 * @n: nsecs in u64 818 * 819 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. 820 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed 821 * for scheduler, not for use in device drivers to calculate timeout value. 822 * 823 * note: 824 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 825 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 826 * 827 * Return: nsecs converted to jiffies value 828 */ 829 unsigned long nsecs_to_jiffies(u64 n) 830 { 831 return (unsigned long)nsecs_to_jiffies64(n); 832 } 833 EXPORT_SYMBOL_GPL(nsecs_to_jiffies); 834 835 /** 836 * timespec64_add_safe - Add two timespec64 values and do a safety check 837 * for overflow. 838 * @lhs: first (left) timespec64 to add 839 * @rhs: second (right) timespec64 to add 840 * 841 * It's assumed that both values are valid (>= 0). 842 * And, each timespec64 is in normalized form. 843 * 844 * Return: sum of @lhs + @rhs 845 */ 846 struct timespec64 timespec64_add_safe(const struct timespec64 lhs, 847 const struct timespec64 rhs) 848 { 849 struct timespec64 res; 850 851 set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec, 852 lhs.tv_nsec + rhs.tv_nsec); 853 854 if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) { 855 res.tv_sec = TIME64_MAX; 856 res.tv_nsec = 0; 857 } 858 859 return res; 860 } 861 862 /** 863 * get_timespec64 - get user's time value into kernel space 864 * @ts: destination &struct timespec64 865 * @uts: user's time value as &struct __kernel_timespec 866 * 867 * Handles compat or 32-bit modes. 868 * 869 * Return: %0 on success or negative errno on error 870 */ 871 int get_timespec64(struct timespec64 *ts, 872 const struct __kernel_timespec __user *uts) 873 { 874 struct __kernel_timespec kts; 875 int ret; 876 877 ret = copy_from_user(&kts, uts, sizeof(kts)); 878 if (ret) 879 return -EFAULT; 880 881 ts->tv_sec = kts.tv_sec; 882 883 /* Zero out the padding in compat mode */ 884 if (in_compat_syscall()) 885 kts.tv_nsec &= 0xFFFFFFFFUL; 886 887 /* In 32-bit mode, this drops the padding */ 888 ts->tv_nsec = kts.tv_nsec; 889 890 return 0; 891 } 892 EXPORT_SYMBOL_GPL(get_timespec64); 893 894 /** 895 * put_timespec64 - convert timespec64 value to __kernel_timespec format and 896 * copy the latter to userspace 897 * @ts: input &struct timespec64 898 * @uts: user's &struct __kernel_timespec 899 * 900 * Return: %0 on success or negative errno on error 901 */ 902 int put_timespec64(const struct timespec64 *ts, 903 struct __kernel_timespec __user *uts) 904 { 905 struct __kernel_timespec kts = { 906 .tv_sec = ts->tv_sec, 907 .tv_nsec = ts->tv_nsec 908 }; 909 910 return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0; 911 } 912 EXPORT_SYMBOL_GPL(put_timespec64); 913 914 static int __get_old_timespec32(struct timespec64 *ts64, 915 const struct old_timespec32 __user *cts) 916 { 917 struct old_timespec32 ts; 918 int ret; 919 920 ret = copy_from_user(&ts, cts, sizeof(ts)); 921 if (ret) 922 return -EFAULT; 923 924 ts64->tv_sec = ts.tv_sec; 925 ts64->tv_nsec = ts.tv_nsec; 926 927 return 0; 928 } 929 930 static int __put_old_timespec32(const struct timespec64 *ts64, 931 struct old_timespec32 __user *cts) 932 { 933 struct old_timespec32 ts = { 934 .tv_sec = ts64->tv_sec, 935 .tv_nsec = ts64->tv_nsec 936 }; 937 return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0; 938 } 939 940 /** 941 * get_old_timespec32 - get user's old-format time value into kernel space 942 * @ts: destination &struct timespec64 943 * @uts: user's old-format time value (&struct old_timespec32) 944 * 945 * Handles X86_X32_ABI compatibility conversion. 946 * 947 * Return: %0 on success or negative errno on error 948 */ 949 int get_old_timespec32(struct timespec64 *ts, const void __user *uts) 950 { 951 if (COMPAT_USE_64BIT_TIME) 952 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0; 953 else 954 return __get_old_timespec32(ts, uts); 955 } 956 EXPORT_SYMBOL_GPL(get_old_timespec32); 957 958 /** 959 * put_old_timespec32 - convert timespec64 value to &struct old_timespec32 and 960 * copy the latter to userspace 961 * @ts: input &struct timespec64 962 * @uts: user's &struct old_timespec32 963 * 964 * Handles X86_X32_ABI compatibility conversion. 965 * 966 * Return: %0 on success or negative errno on error 967 */ 968 int put_old_timespec32(const struct timespec64 *ts, void __user *uts) 969 { 970 if (COMPAT_USE_64BIT_TIME) 971 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0; 972 else 973 return __put_old_timespec32(ts, uts); 974 } 975 EXPORT_SYMBOL_GPL(put_old_timespec32); 976 977 /** 978 * get_itimerspec64 - get user's &struct __kernel_itimerspec into kernel space 979 * @it: destination &struct itimerspec64 980 * @uit: user's &struct __kernel_itimerspec 981 * 982 * Return: %0 on success or negative errno on error 983 */ 984 int get_itimerspec64(struct itimerspec64 *it, 985 const struct __kernel_itimerspec __user *uit) 986 { 987 int ret; 988 989 ret = get_timespec64(&it->it_interval, &uit->it_interval); 990 if (ret) 991 return ret; 992 993 ret = get_timespec64(&it->it_value, &uit->it_value); 994 995 return ret; 996 } 997 EXPORT_SYMBOL_GPL(get_itimerspec64); 998 999 /** 1000 * put_itimerspec64 - convert &struct itimerspec64 to __kernel_itimerspec format 1001 * and copy the latter to userspace 1002 * @it: input &struct itimerspec64 1003 * @uit: user's &struct __kernel_itimerspec 1004 * 1005 * Return: %0 on success or negative errno on error 1006 */ 1007 int put_itimerspec64(const struct itimerspec64 *it, 1008 struct __kernel_itimerspec __user *uit) 1009 { 1010 int ret; 1011 1012 ret = put_timespec64(&it->it_interval, &uit->it_interval); 1013 if (ret) 1014 return ret; 1015 1016 ret = put_timespec64(&it->it_value, &uit->it_value); 1017 1018 return ret; 1019 } 1020 EXPORT_SYMBOL_GPL(put_itimerspec64); 1021 1022 /** 1023 * get_old_itimerspec32 - get user's &struct old_itimerspec32 into kernel space 1024 * @its: destination &struct itimerspec64 1025 * @uits: user's &struct old_itimerspec32 1026 * 1027 * Return: %0 on success or negative errno on error 1028 */ 1029 int get_old_itimerspec32(struct itimerspec64 *its, 1030 const struct old_itimerspec32 __user *uits) 1031 { 1032 1033 if (__get_old_timespec32(&its->it_interval, &uits->it_interval) || 1034 __get_old_timespec32(&its->it_value, &uits->it_value)) 1035 return -EFAULT; 1036 return 0; 1037 } 1038 EXPORT_SYMBOL_GPL(get_old_itimerspec32); 1039 1040 /** 1041 * put_old_itimerspec32 - convert &struct itimerspec64 to &struct 1042 * old_itimerspec32 and copy the latter to userspace 1043 * @its: input &struct itimerspec64 1044 * @uits: user's &struct old_itimerspec32 1045 * 1046 * Return: %0 on success or negative errno on error 1047 */ 1048 int put_old_itimerspec32(const struct itimerspec64 *its, 1049 struct old_itimerspec32 __user *uits) 1050 { 1051 if (__put_old_timespec32(&its->it_interval, &uits->it_interval) || 1052 __put_old_timespec32(&its->it_value, &uits->it_value)) 1053 return -EFAULT; 1054 return 0; 1055 } 1056 EXPORT_SYMBOL_GPL(put_old_itimerspec32); 1057