projects/linux·blob v4.20 · refs

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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 */
53struct timezone sys_tz;
54
55EXPORT_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 */
65SYSCALL_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
84SYSCALL_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/* old_time32_t is a 32 bit "long" and needs to get converted. */
108COMPAT_SYSCALL_DEFINE1(time, old_time32_t __user *, tloc)
109{
110 old_time32_t i;
111
112 i = (old_time32_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
122COMPAT_SYSCALL_DEFINE1(stime, old_time32_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
143SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv,
144 struct timezone __user *, tz)
145{
146 if (likely(tv != NULL)) {
147 struct timespec64 ts;
148
149 ktime_get_real_ts64(&ts);
150 if (put_user(ts.tv_sec, &tv->tv_sec) ||
151 put_user(ts.tv_nsec / 1000, &tv->tv_usec))
152 return -EFAULT;
153 }
154 if (unlikely(tz != NULL)) {
155 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
156 return -EFAULT;
157 }
158 return 0;
159}
160
161/*
162 * In case for some reason the CMOS clock has not already been running
163 * in UTC, but in some local time: The first time we set the timezone,
164 * we will warp the clock so that it is ticking UTC time instead of
165 * local time. Presumably, if someone is setting the timezone then we
166 * are running in an environment where the programs understand about
167 * timezones. This should be done at boot time in the /etc/rc script,
168 * as soon as possible, so that the clock can be set right. Otherwise,
169 * various programs will get confused when the clock gets warped.
170 */
171
172int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz)
173{
174 static int firsttime = 1;
175 int error = 0;
176
177 if (tv && !timespec64_valid(tv))
178 return -EINVAL;
179
180 error = security_settime64(tv, tz);
181 if (error)
182 return error;
183
184 if (tz) {
185 /* Verify we're witin the +-15 hrs range */
186 if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60)
187 return -EINVAL;
188
189 sys_tz = *tz;
190 update_vsyscall_tz();
191 if (firsttime) {
192 firsttime = 0;
193 if (!tv)
194 timekeeping_warp_clock();
195 }
196 }
197 if (tv)
198 return do_settimeofday64(tv);
199 return 0;
200}
201
202SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
203 struct timezone __user *, tz)
204{
205 struct timespec64 new_ts;
206 struct timeval user_tv;
207 struct timezone new_tz;
208
209 if (tv) {
210 if (copy_from_user(&user_tv, tv, sizeof(*tv)))
211 return -EFAULT;
212
213 if (!timeval_valid(&user_tv))
214 return -EINVAL;
215
216 new_ts.tv_sec = user_tv.tv_sec;
217 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
218 }
219 if (tz) {
220 if (copy_from_user(&new_tz, tz, sizeof(*tz)))
221 return -EFAULT;
222 }
223
224 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
225}
226
227#ifdef CONFIG_COMPAT
228COMPAT_SYSCALL_DEFINE2(gettimeofday, struct old_timeval32 __user *, tv,
229 struct timezone __user *, tz)
230{
231 if (tv) {
232 struct timespec64 ts;
233
234 ktime_get_real_ts64(&ts);
235 if (put_user(ts.tv_sec, &tv->tv_sec) ||
236 put_user(ts.tv_nsec / 1000, &tv->tv_usec))
237 return -EFAULT;
238 }
239 if (tz) {
240 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
241 return -EFAULT;
242 }
243
244 return 0;
245}
246
247COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv,
248 struct timezone __user *, tz)
249{
250 struct timespec64 new_ts;
251 struct timeval user_tv;
252 struct timezone new_tz;
253
254 if (tv) {
255 if (compat_get_timeval(&user_tv, tv))
256 return -EFAULT;
257 new_ts.tv_sec = user_tv.tv_sec;
258 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
259 }
260 if (tz) {
261 if (copy_from_user(&new_tz, tz, sizeof(*tz)))
262 return -EFAULT;
263 }
264
265 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
266}
267#endif
268
269SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p)
270{
271 struct 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 timex)))
279 return -EFAULT;
280 ret = do_adjtimex(&txc);
281 return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
282}
283
284#ifdef CONFIG_COMPAT
285
286COMPAT_SYSCALL_DEFINE1(adjtimex, struct compat_timex __user *, utp)
287{
288 struct timex txc;
289 int err, ret;
290
291 err = compat_get_timex(&txc, utp);
292 if (err)
293 return err;
294
295 ret = do_adjtimex(&txc);
296
297 err = compat_put_timex(utp, &txc);
298 if (err)
299 return err;
300
301 return ret;
302}
303#endif
304
305/*
306 * Convert jiffies to milliseconds and back.
307 *
308 * Avoid unnecessary multiplications/divisions in the
309 * two most common HZ cases:
310 */
311unsigned int jiffies_to_msecs(const unsigned long j)
312{
313#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
314 return (MSEC_PER_SEC / HZ) * j;
315#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
316 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
317#else
318# if BITS_PER_LONG == 32
319 return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >>
320 HZ_TO_MSEC_SHR32;
321# else
322 return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
323# endif
324#endif
325}
326EXPORT_SYMBOL(jiffies_to_msecs);
327
328unsigned int jiffies_to_usecs(const unsigned long j)
329{
330 /*
331 * Hz usually doesn't go much further MSEC_PER_SEC.
332 * jiffies_to_usecs() and usecs_to_jiffies() depend on that.
333 */
334 BUILD_BUG_ON(HZ > USEC_PER_SEC);
335
336#if !(USEC_PER_SEC % HZ)
337 return (USEC_PER_SEC / HZ) * j;
338#else
339# if BITS_PER_LONG == 32
340 return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
341# else
342 return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
343# endif
344#endif
345}
346EXPORT_SYMBOL(jiffies_to_usecs);
347
348/*
349 * mktime64 - Converts date to seconds.
350 * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
351 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
352 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
353 *
354 * [For the Julian calendar (which was used in Russia before 1917,
355 * Britain & colonies before 1752, anywhere else before 1582,
356 * and is still in use by some communities) leave out the
357 * -year/100+year/400 terms, and add 10.]
358 *
359 * This algorithm was first published by Gauss (I think).
360 *
361 * A leap second can be indicated by calling this function with sec as
362 * 60 (allowable under ISO 8601). The leap second is treated the same
363 * as the following second since they don't exist in UNIX time.
364 *
365 * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight
366 * tomorrow - (allowable under ISO 8601) is supported.
367 */
368time64_t mktime64(const unsigned int year0, const unsigned int mon0,
369 const unsigned int day, const unsigned int hour,
370 const unsigned int min, const unsigned int sec)
371{
372 unsigned int mon = mon0, year = year0;
373
374 /* 1..12 -> 11,12,1..10 */
375 if (0 >= (int) (mon -= 2)) {
376 mon += 12; /* Puts Feb last since it has leap day */
377 year -= 1;
378 }
379
380 return ((((time64_t)
381 (year/4 - year/100 + year/400 + 367*mon/12 + day) +
382 year*365 - 719499
383 )*24 + hour /* now have hours - midnight tomorrow handled here */
384 )*60 + min /* now have minutes */
385 )*60 + sec; /* finally seconds */
386}
387EXPORT_SYMBOL(mktime64);
388
389/**
390 * set_normalized_timespec - set timespec sec and nsec parts and normalize
391 *
392 * @ts: pointer to timespec variable to be set
393 * @sec: seconds to set
394 * @nsec: nanoseconds to set
395 *
396 * Set seconds and nanoseconds field of a timespec variable and
397 * normalize to the timespec storage format
398 *
399 * Note: The tv_nsec part is always in the range of
400 * 0 <= tv_nsec < NSEC_PER_SEC
401 * For negative values only the tv_sec field is negative !
402 */
403void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec)
404{
405 while (nsec >= NSEC_PER_SEC) {
406 /*
407 * The following asm() prevents the compiler from
408 * optimising this loop into a modulo operation. See
409 * also __iter_div_u64_rem() in include/linux/time.h
410 */
411 asm("" : "+rm"(nsec));
412 nsec -= NSEC_PER_SEC;
413 ++sec;
414 }
415 while (nsec < 0) {
416 asm("" : "+rm"(nsec));
417 nsec += NSEC_PER_SEC;
418 --sec;
419 }
420 ts->tv_sec = sec;
421 ts->tv_nsec = nsec;
422}
423EXPORT_SYMBOL(set_normalized_timespec);
424
425/**
426 * ns_to_timespec - Convert nanoseconds to timespec
427 * @nsec: the nanoseconds value to be converted
428 *
429 * Returns the timespec representation of the nsec parameter.
430 */
431struct timespec ns_to_timespec(const s64 nsec)
432{
433 struct timespec ts;
434 s32 rem;
435
436 if (!nsec)
437 return (struct timespec) {0, 0};
438
439 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
440 if (unlikely(rem < 0)) {
441 ts.tv_sec--;
442 rem += NSEC_PER_SEC;
443 }
444 ts.tv_nsec = rem;
445
446 return ts;
447}
448EXPORT_SYMBOL(ns_to_timespec);
449
450/**
451 * ns_to_timeval - Convert nanoseconds to timeval
452 * @nsec: the nanoseconds value to be converted
453 *
454 * Returns the timeval representation of the nsec parameter.
455 */
456struct timeval ns_to_timeval(const s64 nsec)
457{
458 struct timespec ts = ns_to_timespec(nsec);
459 struct timeval tv;
460
461 tv.tv_sec = ts.tv_sec;
462 tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000;
463
464 return tv;
465}
466EXPORT_SYMBOL(ns_to_timeval);
467
468struct __kernel_old_timeval ns_to_kernel_old_timeval(const s64 nsec)
469{
470 struct timespec64 ts = ns_to_timespec64(nsec);
471 struct __kernel_old_timeval tv;
472
473 tv.tv_sec = ts.tv_sec;
474 tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000;
475
476 return tv;
477}
478EXPORT_SYMBOL(ns_to_kernel_old_timeval);
479
480/**
481 * set_normalized_timespec - set timespec sec and nsec parts and normalize
482 *
483 * @ts: pointer to timespec variable to be set
484 * @sec: seconds to set
485 * @nsec: nanoseconds to set
486 *
487 * Set seconds and nanoseconds field of a timespec variable and
488 * normalize to the timespec storage format
489 *
490 * Note: The tv_nsec part is always in the range of
491 * 0 <= tv_nsec < NSEC_PER_SEC
492 * For negative values only the tv_sec field is negative !
493 */
494void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
495{
496 while (nsec >= NSEC_PER_SEC) {
497 /*
498 * The following asm() prevents the compiler from
499 * optimising this loop into a modulo operation. See
500 * also __iter_div_u64_rem() in include/linux/time.h
501 */
502 asm("" : "+rm"(nsec));
503 nsec -= NSEC_PER_SEC;
504 ++sec;
505 }
506 while (nsec < 0) {
507 asm("" : "+rm"(nsec));
508 nsec += NSEC_PER_SEC;
509 --sec;
510 }
511 ts->tv_sec = sec;
512 ts->tv_nsec = nsec;
513}
514EXPORT_SYMBOL(set_normalized_timespec64);
515
516/**
517 * ns_to_timespec64 - Convert nanoseconds to timespec64
518 * @nsec: the nanoseconds value to be converted
519 *
520 * Returns the timespec64 representation of the nsec parameter.
521 */
522struct timespec64 ns_to_timespec64(const s64 nsec)
523{
524 struct timespec64 ts;
525 s32 rem;
526
527 if (!nsec)
528 return (struct timespec64) {0, 0};
529
530 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
531 if (unlikely(rem < 0)) {
532 ts.tv_sec--;
533 rem += NSEC_PER_SEC;
534 }
535 ts.tv_nsec = rem;
536
537 return ts;
538}
539EXPORT_SYMBOL(ns_to_timespec64);
540
541/**
542 * msecs_to_jiffies: - convert milliseconds to jiffies
543 * @m: time in milliseconds
544 *
545 * conversion is done as follows:
546 *
547 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
548 *
549 * - 'too large' values [that would result in larger than
550 * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
551 *
552 * - all other values are converted to jiffies by either multiplying
553 * the input value by a factor or dividing it with a factor and
554 * handling any 32-bit overflows.
555 * for the details see __msecs_to_jiffies()
556 *
557 * msecs_to_jiffies() checks for the passed in value being a constant
558 * via __builtin_constant_p() allowing gcc to eliminate most of the
559 * code, __msecs_to_jiffies() is called if the value passed does not
560 * allow constant folding and the actual conversion must be done at
561 * runtime.
562 * the _msecs_to_jiffies helpers are the HZ dependent conversion
563 * routines found in include/linux/jiffies.h
564 */
565unsigned long __msecs_to_jiffies(const unsigned int m)
566{
567 /*
568 * Negative value, means infinite timeout:
569 */
570 if ((int)m < 0)
571 return MAX_JIFFY_OFFSET;
572 return _msecs_to_jiffies(m);
573}
574EXPORT_SYMBOL(__msecs_to_jiffies);
575
576unsigned long __usecs_to_jiffies(const unsigned int u)
577{
578 if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
579 return MAX_JIFFY_OFFSET;
580 return _usecs_to_jiffies(u);
581}
582EXPORT_SYMBOL(__usecs_to_jiffies);
583
584/*
585 * The TICK_NSEC - 1 rounds up the value to the next resolution. Note
586 * that a remainder subtract here would not do the right thing as the
587 * resolution values don't fall on second boundries. I.e. the line:
588 * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
589 * Note that due to the small error in the multiplier here, this
590 * rounding is incorrect for sufficiently large values of tv_nsec, but
591 * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're
592 * OK.
593 *
594 * Rather, we just shift the bits off the right.
595 *
596 * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
597 * value to a scaled second value.
598 */
599static unsigned long
600__timespec64_to_jiffies(u64 sec, long nsec)
601{
602 nsec = nsec + TICK_NSEC - 1;
603
604 if (sec >= MAX_SEC_IN_JIFFIES){
605 sec = MAX_SEC_IN_JIFFIES;
606 nsec = 0;
607 }
608 return ((sec * SEC_CONVERSION) +
609 (((u64)nsec * NSEC_CONVERSION) >>
610 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
611
612}
613
614static unsigned long
615__timespec_to_jiffies(unsigned long sec, long nsec)
616{
617 return __timespec64_to_jiffies((u64)sec, nsec);
618}
619
620unsigned long
621timespec64_to_jiffies(const struct timespec64 *value)
622{
623 return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec);
624}
625EXPORT_SYMBOL(timespec64_to_jiffies);
626
627void
628jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
629{
630 /*
631 * Convert jiffies to nanoseconds and separate with
632 * one divide.
633 */
634 u32 rem;
635 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
636 NSEC_PER_SEC, &rem);
637 value->tv_nsec = rem;
638}
639EXPORT_SYMBOL(jiffies_to_timespec64);
640
641/*
642 * We could use a similar algorithm to timespec_to_jiffies (with a
643 * different multiplier for usec instead of nsec). But this has a
644 * problem with rounding: we can't exactly add TICK_NSEC - 1 to the
645 * usec value, since it's not necessarily integral.
646 *
647 * We could instead round in the intermediate scaled representation
648 * (i.e. in units of 1/2^(large scale) jiffies) but that's also
649 * perilous: the scaling introduces a small positive error, which
650 * combined with a division-rounding-upward (i.e. adding 2^(scale) - 1
651 * units to the intermediate before shifting) leads to accidental
652 * overflow and overestimates.
653 *
654 * At the cost of one additional multiplication by a constant, just
655 * use the timespec implementation.
656 */
657unsigned long
658timeval_to_jiffies(const struct timeval *value)
659{
660 return __timespec_to_jiffies(value->tv_sec,
661 value->tv_usec * NSEC_PER_USEC);
662}
663EXPORT_SYMBOL(timeval_to_jiffies);
664
665void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
666{
667 /*
668 * Convert jiffies to nanoseconds and separate with
669 * one divide.
670 */
671 u32 rem;
672
673 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
674 NSEC_PER_SEC, &rem);
675 value->tv_usec = rem / NSEC_PER_USEC;
676}
677EXPORT_SYMBOL(jiffies_to_timeval);
678
679/*
680 * Convert jiffies/jiffies_64 to clock_t and back.
681 */
682clock_t jiffies_to_clock_t(unsigned long x)
683{
684#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
685# if HZ < USER_HZ
686 return x * (USER_HZ / HZ);
687# else
688 return x / (HZ / USER_HZ);
689# endif
690#else
691 return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
692#endif
693}
694EXPORT_SYMBOL(jiffies_to_clock_t);
695
696unsigned long clock_t_to_jiffies(unsigned long x)
697{
698#if (HZ % USER_HZ)==0
699 if (x >= ~0UL / (HZ / USER_HZ))
700 return ~0UL;
701 return x * (HZ / USER_HZ);
702#else
703 /* Don't worry about loss of precision here .. */
704 if (x >= ~0UL / HZ * USER_HZ)
705 return ~0UL;
706
707 /* .. but do try to contain it here */
708 return div_u64((u64)x * HZ, USER_HZ);
709#endif
710}
711EXPORT_SYMBOL(clock_t_to_jiffies);
712
713u64 jiffies_64_to_clock_t(u64 x)
714{
715#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
716# if HZ < USER_HZ
717 x = div_u64(x * USER_HZ, HZ);
718# elif HZ > USER_HZ
719 x = div_u64(x, HZ / USER_HZ);
720# else
721 /* Nothing to do */
722# endif
723#else
724 /*
725 * There are better ways that don't overflow early,
726 * but even this doesn't overflow in hundreds of years
727 * in 64 bits, so..
728 */
729 x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
730#endif
731 return x;
732}
733EXPORT_SYMBOL(jiffies_64_to_clock_t);
734
735u64 nsec_to_clock_t(u64 x)
736{
737#if (NSEC_PER_SEC % USER_HZ) == 0
738 return div_u64(x, NSEC_PER_SEC / USER_HZ);
739#elif (USER_HZ % 512) == 0
740 return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
741#else
742 /*
743 * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
744 * overflow after 64.99 years.
745 * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
746 */
747 return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
748#endif
749}
750
751u64 jiffies64_to_nsecs(u64 j)
752{
753#if !(NSEC_PER_SEC % HZ)
754 return (NSEC_PER_SEC / HZ) * j;
755# else
756 return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN);
757#endif
758}
759EXPORT_SYMBOL(jiffies64_to_nsecs);
760
761/**
762 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
763 *
764 * @n: nsecs in u64
765 *
766 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
767 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
768 * for scheduler, not for use in device drivers to calculate timeout value.
769 *
770 * note:
771 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
772 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
773 */
774u64 nsecs_to_jiffies64(u64 n)
775{
776#if (NSEC_PER_SEC % HZ) == 0
777 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
778 return div_u64(n, NSEC_PER_SEC / HZ);
779#elif (HZ % 512) == 0
780 /* overflow after 292 years if HZ = 1024 */
781 return div_u64(n * HZ / 512, NSEC_PER_SEC / 512);
782#else
783 /*
784 * Generic case - optimized for cases where HZ is a multiple of 3.
785 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc.
786 */
787 return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ);
788#endif
789}
790EXPORT_SYMBOL(nsecs_to_jiffies64);
791
792/**
793 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
794 *
795 * @n: nsecs in u64
796 *
797 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
798 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
799 * for scheduler, not for use in device drivers to calculate timeout value.
800 *
801 * note:
802 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
803 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
804 */
805unsigned long nsecs_to_jiffies(u64 n)
806{
807 return (unsigned long)nsecs_to_jiffies64(n);
808}
809EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
810
811/*
812 * Add two timespec64 values and do a safety check for overflow.
813 * It's assumed that both values are valid (>= 0).
814 * And, each timespec64 is in normalized form.
815 */
816struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
817 const struct timespec64 rhs)
818{
819 struct timespec64 res;
820
821 set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
822 lhs.tv_nsec + rhs.tv_nsec);
823
824 if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
825 res.tv_sec = TIME64_MAX;
826 res.tv_nsec = 0;
827 }
828
829 return res;
830}
831
832int get_timespec64(struct timespec64 *ts,
833 const struct __kernel_timespec __user *uts)
834{
835 struct __kernel_timespec kts;
836 int ret;
837
838 ret = copy_from_user(&kts, uts, sizeof(kts));
839 if (ret)
840 return -EFAULT;
841
842 ts->tv_sec = kts.tv_sec;
843
844 /* Zero out the padding for 32 bit systems or in compat mode */
845 if (IS_ENABLED(CONFIG_64BIT_TIME) && in_compat_syscall())
846 kts.tv_nsec &= 0xFFFFFFFFUL;
847
848 ts->tv_nsec = kts.tv_nsec;
849
850 return 0;
851}
852EXPORT_SYMBOL_GPL(get_timespec64);
853
854int put_timespec64(const struct timespec64 *ts,
855 struct __kernel_timespec __user *uts)
856{
857 struct __kernel_timespec kts = {
858 .tv_sec = ts->tv_sec,
859 .tv_nsec = ts->tv_nsec
860 };
861
862 return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0;
863}
864EXPORT_SYMBOL_GPL(put_timespec64);
865
866static int __get_old_timespec32(struct timespec64 *ts64,
867 const struct old_timespec32 __user *cts)
868{
869 struct old_timespec32 ts;
870 int ret;
871
872 ret = copy_from_user(&ts, cts, sizeof(ts));
873 if (ret)
874 return -EFAULT;
875
876 ts64->tv_sec = ts.tv_sec;
877 ts64->tv_nsec = ts.tv_nsec;
878
879 return 0;
880}
881
882static int __put_old_timespec32(const struct timespec64 *ts64,
883 struct old_timespec32 __user *cts)
884{
885 struct old_timespec32 ts = {
886 .tv_sec = ts64->tv_sec,
887 .tv_nsec = ts64->tv_nsec
888 };
889 return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0;
890}
891
892int get_old_timespec32(struct timespec64 *ts, const void __user *uts)
893{
894 if (COMPAT_USE_64BIT_TIME)
895 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
896 else
897 return __get_old_timespec32(ts, uts);
898}
899EXPORT_SYMBOL_GPL(get_old_timespec32);
900
901int put_old_timespec32(const struct timespec64 *ts, void __user *uts)
902{
903 if (COMPAT_USE_64BIT_TIME)
904 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
905 else
906 return __put_old_timespec32(ts, uts);
907}
908EXPORT_SYMBOL_GPL(put_old_timespec32);
909
910int get_itimerspec64(struct itimerspec64 *it,
911 const struct __kernel_itimerspec __user *uit)
912{
913 int ret;
914
915 ret = get_timespec64(&it->it_interval, &uit->it_interval);
916 if (ret)
917 return ret;
918
919 ret = get_timespec64(&it->it_value, &uit->it_value);
920
921 return ret;
922}
923EXPORT_SYMBOL_GPL(get_itimerspec64);
924
925int put_itimerspec64(const struct itimerspec64 *it,
926 struct __kernel_itimerspec __user *uit)
927{
928 int ret;
929
930 ret = put_timespec64(&it->it_interval, &uit->it_interval);
931 if (ret)
932 return ret;
933
934 ret = put_timespec64(&it->it_value, &uit->it_value);
935
936 return ret;
937}
938EXPORT_SYMBOL_GPL(put_itimerspec64);
939
940int get_old_itimerspec32(struct itimerspec64 *its,
941 const struct old_itimerspec32 __user *uits)
942{
943
944 if (__get_old_timespec32(&its->it_interval, &uits->it_interval) ||
945 __get_old_timespec32(&its->it_value, &uits->it_value))
946 return -EFAULT;
947 return 0;
948}
949EXPORT_SYMBOL_GPL(get_old_itimerspec32);
950
951int put_old_itimerspec32(const struct itimerspec64 *its,
952 struct old_itimerspec32 __user *uits)
953{
954 if (__put_old_timespec32(&its->it_interval, &uits->it_interval) ||
955 __put_old_timespec32(&its->it_value, &uits->it_value))
956 return -EFAULT;
957 return 0;
958}
959EXPORT_SYMBOL_GPL(put_old_itimerspec32);