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 * Convert jiffies to milliseconds and back. 370 * 371 * Avoid unnecessary multiplications/divisions in the 372 * two most common HZ cases: 373 */ 374 unsigned int jiffies_to_msecs(const unsigned long j) 375 { 376 #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) 377 return (MSEC_PER_SEC / HZ) * j; 378 #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) 379 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); 380 #else 381 # if BITS_PER_LONG == 32 382 return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >> 383 HZ_TO_MSEC_SHR32; 384 # else 385 return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN); 386 # endif 387 #endif 388 } 389 EXPORT_SYMBOL(jiffies_to_msecs); 390 391 unsigned int jiffies_to_usecs(const unsigned long j) 392 { 393 /* 394 * Hz usually doesn't go much further MSEC_PER_SEC. 395 * jiffies_to_usecs() and usecs_to_jiffies() depend on that. 396 */ 397 BUILD_BUG_ON(HZ > USEC_PER_SEC); 398 399 #if !(USEC_PER_SEC % HZ) 400 return (USEC_PER_SEC / HZ) * j; 401 #else 402 # if BITS_PER_LONG == 32 403 return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32; 404 # else 405 return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN; 406 # endif 407 #endif 408 } 409 EXPORT_SYMBOL(jiffies_to_usecs); 410 411 /* 412 * mktime64 - Converts date to seconds. 413 * Converts Gregorian date to seconds since 1970-01-01 00:00:00. 414 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 415 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. 416 * 417 * [For the Julian calendar (which was used in Russia before 1917, 418 * Britain & colonies before 1752, anywhere else before 1582, 419 * and is still in use by some communities) leave out the 420 * -year/100+year/400 terms, and add 10.] 421 * 422 * This algorithm was first published by Gauss (I think). 423 * 424 * A leap second can be indicated by calling this function with sec as 425 * 60 (allowable under ISO 8601). The leap second is treated the same 426 * as the following second since they don't exist in UNIX time. 427 * 428 * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight 429 * tomorrow - (allowable under ISO 8601) is supported. 430 */ 431 time64_t mktime64(const unsigned int year0, const unsigned int mon0, 432 const unsigned int day, const unsigned int hour, 433 const unsigned int min, const unsigned int sec) 434 { 435 unsigned int mon = mon0, year = year0; 436 437 /* 1..12 -> 11,12,1..10 */ 438 if (0 >= (int) (mon -= 2)) { 439 mon += 12; /* Puts Feb last since it has leap day */ 440 year -= 1; 441 } 442 443 return ((((time64_t) 444 (year/4 - year/100 + year/400 + 367*mon/12 + day) + 445 year*365 - 719499 446 )*24 + hour /* now have hours - midnight tomorrow handled here */ 447 )*60 + min /* now have minutes */ 448 )*60 + sec; /* finally seconds */ 449 } 450 EXPORT_SYMBOL(mktime64); 451 452 struct __kernel_old_timeval ns_to_kernel_old_timeval(s64 nsec) 453 { 454 struct timespec64 ts = ns_to_timespec64(nsec); 455 struct __kernel_old_timeval tv; 456 457 tv.tv_sec = ts.tv_sec; 458 tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000; 459 460 return tv; 461 } 462 EXPORT_SYMBOL(ns_to_kernel_old_timeval); 463 464 /** 465 * set_normalized_timespec64 - set timespec sec and nsec parts and normalize 466 * 467 * @ts: pointer to timespec variable to be set 468 * @sec: seconds to set 469 * @nsec: nanoseconds to set 470 * 471 * Set seconds and nanoseconds field of a timespec variable and 472 * normalize to the timespec storage format 473 * 474 * Note: The tv_nsec part is always in the range of 475 * 0 <= tv_nsec < NSEC_PER_SEC 476 * For negative values only the tv_sec field is negative ! 477 */ 478 void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec) 479 { 480 while (nsec >= NSEC_PER_SEC) { 481 /* 482 * The following asm() prevents the compiler from 483 * optimising this loop into a modulo operation. See 484 * also __iter_div_u64_rem() in include/linux/time.h 485 */ 486 asm("" : "+rm"(nsec)); 487 nsec -= NSEC_PER_SEC; 488 ++sec; 489 } 490 while (nsec < 0) { 491 asm("" : "+rm"(nsec)); 492 nsec += NSEC_PER_SEC; 493 --sec; 494 } 495 ts->tv_sec = sec; 496 ts->tv_nsec = nsec; 497 } 498 EXPORT_SYMBOL(set_normalized_timespec64); 499 500 /** 501 * ns_to_timespec64 - Convert nanoseconds to timespec64 502 * @nsec: the nanoseconds value to be converted 503 * 504 * Returns the timespec64 representation of the nsec parameter. 505 */ 506 struct timespec64 ns_to_timespec64(s64 nsec) 507 { 508 struct timespec64 ts = { 0, 0 }; 509 s32 rem; 510 511 if (likely(nsec > 0)) { 512 ts.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem); 513 ts.tv_nsec = rem; 514 } else if (nsec < 0) { 515 /* 516 * With negative times, tv_sec points to the earlier 517 * second, and tv_nsec counts the nanoseconds since 518 * then, so tv_nsec is always a positive number. 519 */ 520 ts.tv_sec = -div_u64_rem(-nsec - 1, NSEC_PER_SEC, &rem) - 1; 521 ts.tv_nsec = NSEC_PER_SEC - rem - 1; 522 } 523 524 return ts; 525 } 526 EXPORT_SYMBOL(ns_to_timespec64); 527 528 /** 529 * __msecs_to_jiffies: - convert milliseconds to jiffies 530 * @m: time in milliseconds 531 * 532 * conversion is done as follows: 533 * 534 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) 535 * 536 * - 'too large' values [that would result in larger than 537 * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. 538 * 539 * - all other values are converted to jiffies by either multiplying 540 * the input value by a factor or dividing it with a factor and 541 * handling any 32-bit overflows. 542 * for the details see __msecs_to_jiffies() 543 * 544 * __msecs_to_jiffies() checks for the passed in value being a constant 545 * via __builtin_constant_p() allowing gcc to eliminate most of the 546 * code, __msecs_to_jiffies() is called if the value passed does not 547 * allow constant folding and the actual conversion must be done at 548 * runtime. 549 * The _msecs_to_jiffies helpers are the HZ dependent conversion 550 * routines found in include/linux/jiffies.h 551 */ 552 unsigned long __msecs_to_jiffies(const unsigned int m) 553 { 554 /* 555 * Negative value, means infinite timeout: 556 */ 557 if ((int)m < 0) 558 return MAX_JIFFY_OFFSET; 559 return _msecs_to_jiffies(m); 560 } 561 EXPORT_SYMBOL(__msecs_to_jiffies); 562 563 unsigned long __usecs_to_jiffies(const unsigned int u) 564 { 565 if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) 566 return MAX_JIFFY_OFFSET; 567 return _usecs_to_jiffies(u); 568 } 569 EXPORT_SYMBOL(__usecs_to_jiffies); 570 571 /* 572 * The TICK_NSEC - 1 rounds up the value to the next resolution. Note 573 * that a remainder subtract here would not do the right thing as the 574 * resolution values don't fall on second boundaries. I.e. the line: 575 * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding. 576 * Note that due to the small error in the multiplier here, this 577 * rounding is incorrect for sufficiently large values of tv_nsec, but 578 * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're 579 * OK. 580 * 581 * Rather, we just shift the bits off the right. 582 * 583 * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec 584 * value to a scaled second value. 585 */ 586 587 unsigned long 588 timespec64_to_jiffies(const struct timespec64 *value) 589 { 590 u64 sec = value->tv_sec; 591 long nsec = value->tv_nsec + TICK_NSEC - 1; 592 593 if (sec >= MAX_SEC_IN_JIFFIES){ 594 sec = MAX_SEC_IN_JIFFIES; 595 nsec = 0; 596 } 597 return ((sec * SEC_CONVERSION) + 598 (((u64)nsec * NSEC_CONVERSION) >> 599 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; 600 601 } 602 EXPORT_SYMBOL(timespec64_to_jiffies); 603 604 void 605 jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value) 606 { 607 /* 608 * Convert jiffies to nanoseconds and separate with 609 * one divide. 610 */ 611 u32 rem; 612 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, 613 NSEC_PER_SEC, &rem); 614 value->tv_nsec = rem; 615 } 616 EXPORT_SYMBOL(jiffies_to_timespec64); 617 618 /* 619 * Convert jiffies/jiffies_64 to clock_t and back. 620 */ 621 clock_t jiffies_to_clock_t(unsigned long x) 622 { 623 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 624 # if HZ < USER_HZ 625 return x * (USER_HZ / HZ); 626 # else 627 return x / (HZ / USER_HZ); 628 # endif 629 #else 630 return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); 631 #endif 632 } 633 EXPORT_SYMBOL(jiffies_to_clock_t); 634 635 unsigned long clock_t_to_jiffies(unsigned long x) 636 { 637 #if (HZ % USER_HZ)==0 638 if (x >= ~0UL / (HZ / USER_HZ)) 639 return ~0UL; 640 return x * (HZ / USER_HZ); 641 #else 642 /* Don't worry about loss of precision here .. */ 643 if (x >= ~0UL / HZ * USER_HZ) 644 return ~0UL; 645 646 /* .. but do try to contain it here */ 647 return div_u64((u64)x * HZ, USER_HZ); 648 #endif 649 } 650 EXPORT_SYMBOL(clock_t_to_jiffies); 651 652 u64 jiffies_64_to_clock_t(u64 x) 653 { 654 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 655 # if HZ < USER_HZ 656 x = div_u64(x * USER_HZ, HZ); 657 # elif HZ > USER_HZ 658 x = div_u64(x, HZ / USER_HZ); 659 # else 660 /* Nothing to do */ 661 # endif 662 #else 663 /* 664 * There are better ways that don't overflow early, 665 * but even this doesn't overflow in hundreds of years 666 * in 64 bits, so.. 667 */ 668 x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ)); 669 #endif 670 return x; 671 } 672 EXPORT_SYMBOL(jiffies_64_to_clock_t); 673 674 u64 nsec_to_clock_t(u64 x) 675 { 676 #if (NSEC_PER_SEC % USER_HZ) == 0 677 return div_u64(x, NSEC_PER_SEC / USER_HZ); 678 #elif (USER_HZ % 512) == 0 679 return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512); 680 #else 681 /* 682 * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, 683 * overflow after 64.99 years. 684 * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... 685 */ 686 return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ); 687 #endif 688 } 689 690 u64 jiffies64_to_nsecs(u64 j) 691 { 692 #if !(NSEC_PER_SEC % HZ) 693 return (NSEC_PER_SEC / HZ) * j; 694 # else 695 return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN); 696 #endif 697 } 698 EXPORT_SYMBOL(jiffies64_to_nsecs); 699 700 u64 jiffies64_to_msecs(const u64 j) 701 { 702 #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) 703 return (MSEC_PER_SEC / HZ) * j; 704 #else 705 return div_u64(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN); 706 #endif 707 } 708 EXPORT_SYMBOL(jiffies64_to_msecs); 709 710 /** 711 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64 712 * 713 * @n: nsecs in u64 714 * 715 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. 716 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed 717 * for scheduler, not for use in device drivers to calculate timeout value. 718 * 719 * note: 720 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 721 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 722 */ 723 u64 nsecs_to_jiffies64(u64 n) 724 { 725 #if (NSEC_PER_SEC % HZ) == 0 726 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */ 727 return div_u64(n, NSEC_PER_SEC / HZ); 728 #elif (HZ % 512) == 0 729 /* overflow after 292 years if HZ = 1024 */ 730 return div_u64(n * HZ / 512, NSEC_PER_SEC / 512); 731 #else 732 /* 733 * Generic case - optimized for cases where HZ is a multiple of 3. 734 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc. 735 */ 736 return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ); 737 #endif 738 } 739 EXPORT_SYMBOL(nsecs_to_jiffies64); 740 741 /** 742 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies 743 * 744 * @n: nsecs in u64 745 * 746 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. 747 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed 748 * for scheduler, not for use in device drivers to calculate timeout value. 749 * 750 * note: 751 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 752 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 753 */ 754 unsigned long nsecs_to_jiffies(u64 n) 755 { 756 return (unsigned long)nsecs_to_jiffies64(n); 757 } 758 EXPORT_SYMBOL_GPL(nsecs_to_jiffies); 759 760 /* 761 * Add two timespec64 values and do a safety check for overflow. 762 * It's assumed that both values are valid (>= 0). 763 * And, each timespec64 is in normalized form. 764 */ 765 struct timespec64 timespec64_add_safe(const struct timespec64 lhs, 766 const struct timespec64 rhs) 767 { 768 struct timespec64 res; 769 770 set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec, 771 lhs.tv_nsec + rhs.tv_nsec); 772 773 if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) { 774 res.tv_sec = TIME64_MAX; 775 res.tv_nsec = 0; 776 } 777 778 return res; 779 } 780 781 int get_timespec64(struct timespec64 *ts, 782 const struct __kernel_timespec __user *uts) 783 { 784 struct __kernel_timespec kts; 785 int ret; 786 787 ret = copy_from_user(&kts, uts, sizeof(kts)); 788 if (ret) 789 return -EFAULT; 790 791 ts->tv_sec = kts.tv_sec; 792 793 /* Zero out the padding in compat mode */ 794 if (in_compat_syscall()) 795 kts.tv_nsec &= 0xFFFFFFFFUL; 796 797 /* In 32-bit mode, this drops the padding */ 798 ts->tv_nsec = kts.tv_nsec; 799 800 return 0; 801 } 802 EXPORT_SYMBOL_GPL(get_timespec64); 803 804 int put_timespec64(const struct timespec64 *ts, 805 struct __kernel_timespec __user *uts) 806 { 807 struct __kernel_timespec kts = { 808 .tv_sec = ts->tv_sec, 809 .tv_nsec = ts->tv_nsec 810 }; 811 812 return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0; 813 } 814 EXPORT_SYMBOL_GPL(put_timespec64); 815 816 static int __get_old_timespec32(struct timespec64 *ts64, 817 const struct old_timespec32 __user *cts) 818 { 819 struct old_timespec32 ts; 820 int ret; 821 822 ret = copy_from_user(&ts, cts, sizeof(ts)); 823 if (ret) 824 return -EFAULT; 825 826 ts64->tv_sec = ts.tv_sec; 827 ts64->tv_nsec = ts.tv_nsec; 828 829 return 0; 830 } 831 832 static int __put_old_timespec32(const struct timespec64 *ts64, 833 struct old_timespec32 __user *cts) 834 { 835 struct old_timespec32 ts = { 836 .tv_sec = ts64->tv_sec, 837 .tv_nsec = ts64->tv_nsec 838 }; 839 return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0; 840 } 841 842 int get_old_timespec32(struct timespec64 *ts, const void __user *uts) 843 { 844 if (COMPAT_USE_64BIT_TIME) 845 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0; 846 else 847 return __get_old_timespec32(ts, uts); 848 } 849 EXPORT_SYMBOL_GPL(get_old_timespec32); 850 851 int put_old_timespec32(const struct timespec64 *ts, void __user *uts) 852 { 853 if (COMPAT_USE_64BIT_TIME) 854 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0; 855 else 856 return __put_old_timespec32(ts, uts); 857 } 858 EXPORT_SYMBOL_GPL(put_old_timespec32); 859 860 int get_itimerspec64(struct itimerspec64 *it, 861 const struct __kernel_itimerspec __user *uit) 862 { 863 int ret; 864 865 ret = get_timespec64(&it->it_interval, &uit->it_interval); 866 if (ret) 867 return ret; 868 869 ret = get_timespec64(&it->it_value, &uit->it_value); 870 871 return ret; 872 } 873 EXPORT_SYMBOL_GPL(get_itimerspec64); 874 875 int put_itimerspec64(const struct itimerspec64 *it, 876 struct __kernel_itimerspec __user *uit) 877 { 878 int ret; 879 880 ret = put_timespec64(&it->it_interval, &uit->it_interval); 881 if (ret) 882 return ret; 883 884 ret = put_timespec64(&it->it_value, &uit->it_value); 885 886 return ret; 887 } 888 EXPORT_SYMBOL_GPL(put_itimerspec64); 889 890 int get_old_itimerspec32(struct itimerspec64 *its, 891 const struct old_itimerspec32 __user *uits) 892 { 893 894 if (__get_old_timespec32(&its->it_interval, &uits->it_interval) || 895 __get_old_timespec32(&its->it_value, &uits->it_value)) 896 return -EFAULT; 897 return 0; 898 } 899 EXPORT_SYMBOL_GPL(get_old_itimerspec32); 900 901 int put_old_itimerspec32(const struct itimerspec64 *its, 902 struct old_itimerspec32 __user *uits) 903 { 904 if (__put_old_timespec32(&its->it_interval, &uits->it_interval) || 905 __put_old_timespec32(&its->it_value, &uits->it_value)) 906 return -EFAULT; 907 return 0; 908 } 909 EXPORT_SYMBOL_GPL(put_old_itimerspec32); 910