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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 */
50struct timezone sys_tz;
51
52EXPORT_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 */
62SYSCALL_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
81SYSCALL_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_32BIT_TIME
102#ifdef __ARCH_WANT_SYS_TIME32
103
104/* old_time32_t is a 32 bit "long" and needs to get converted. */
105SYSCALL_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
119SYSCALL_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
140SYSCALL_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
169int 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 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
199SYSCALL_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
225COMPAT_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
244COMPAT_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
255 if (!timeval_valid(&user_tv))
256 return -EINVAL;
257
258 new_ts.tv_sec = user_tv.tv_sec;
259 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
260 }
261 if (tz) {
262 if (copy_from_user(&new_tz, tz, sizeof(*tz)))
263 return -EFAULT;
264 }
265
266 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
267}
268#endif
269
270#if !defined(CONFIG_64BIT_TIME) || defined(CONFIG_64BIT)
271SYSCALL_DEFINE1(adjtimex, struct __kernel_timex __user *, txc_p)
272{
273 struct __kernel_timex txc; /* Local copy of parameter */
274 int ret;
275
276 /* Copy the user data space into the kernel copy
277 * structure. But bear in mind that the structures
278 * may change
279 */
280 if (copy_from_user(&txc, txc_p, sizeof(struct __kernel_timex)))
281 return -EFAULT;
282 ret = do_adjtimex(&txc);
283 return copy_to_user(txc_p, &txc, sizeof(struct __kernel_timex)) ? -EFAULT : ret;
284}
285#endif
286
287#ifdef CONFIG_COMPAT_32BIT_TIME
288int get_old_timex32(struct __kernel_timex *txc, const struct old_timex32 __user *utp)
289{
290 struct old_timex32 tx32;
291
292 memset(txc, 0, sizeof(struct __kernel_timex));
293 if (copy_from_user(&tx32, utp, sizeof(struct old_timex32)))
294 return -EFAULT;
295
296 txc->modes = tx32.modes;
297 txc->offset = tx32.offset;
298 txc->freq = tx32.freq;
299 txc->maxerror = tx32.maxerror;
300 txc->esterror = tx32.esterror;
301 txc->status = tx32.status;
302 txc->constant = tx32.constant;
303 txc->precision = tx32.precision;
304 txc->tolerance = tx32.tolerance;
305 txc->time.tv_sec = tx32.time.tv_sec;
306 txc->time.tv_usec = tx32.time.tv_usec;
307 txc->tick = tx32.tick;
308 txc->ppsfreq = tx32.ppsfreq;
309 txc->jitter = tx32.jitter;
310 txc->shift = tx32.shift;
311 txc->stabil = tx32.stabil;
312 txc->jitcnt = tx32.jitcnt;
313 txc->calcnt = tx32.calcnt;
314 txc->errcnt = tx32.errcnt;
315 txc->stbcnt = tx32.stbcnt;
316
317 return 0;
318}
319
320int put_old_timex32(struct old_timex32 __user *utp, const struct __kernel_timex *txc)
321{
322 struct old_timex32 tx32;
323
324 memset(&tx32, 0, sizeof(struct old_timex32));
325 tx32.modes = txc->modes;
326 tx32.offset = txc->offset;
327 tx32.freq = txc->freq;
328 tx32.maxerror = txc->maxerror;
329 tx32.esterror = txc->esterror;
330 tx32.status = txc->status;
331 tx32.constant = txc->constant;
332 tx32.precision = txc->precision;
333 tx32.tolerance = txc->tolerance;
334 tx32.time.tv_sec = txc->time.tv_sec;
335 tx32.time.tv_usec = txc->time.tv_usec;
336 tx32.tick = txc->tick;
337 tx32.ppsfreq = txc->ppsfreq;
338 tx32.jitter = txc->jitter;
339 tx32.shift = txc->shift;
340 tx32.stabil = txc->stabil;
341 tx32.jitcnt = txc->jitcnt;
342 tx32.calcnt = txc->calcnt;
343 tx32.errcnt = txc->errcnt;
344 tx32.stbcnt = txc->stbcnt;
345 tx32.tai = txc->tai;
346 if (copy_to_user(utp, &tx32, sizeof(struct old_timex32)))
347 return -EFAULT;
348 return 0;
349}
350
351SYSCALL_DEFINE1(adjtimex_time32, struct old_timex32 __user *, utp)
352{
353 struct __kernel_timex txc;
354 int err, ret;
355
356 err = get_old_timex32(&txc, utp);
357 if (err)
358 return err;
359
360 ret = do_adjtimex(&txc);
361
362 err = put_old_timex32(utp, &txc);
363 if (err)
364 return err;
365
366 return ret;
367}
368#endif
369
370/*
371 * Convert jiffies to milliseconds and back.
372 *
373 * Avoid unnecessary multiplications/divisions in the
374 * two most common HZ cases:
375 */
376unsigned int jiffies_to_msecs(const unsigned long j)
377{
378#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
379 return (MSEC_PER_SEC / HZ) * j;
380#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
381 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
382#else
383# if BITS_PER_LONG == 32
384 return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >>
385 HZ_TO_MSEC_SHR32;
386# else
387 return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
388# endif
389#endif
390}
391EXPORT_SYMBOL(jiffies_to_msecs);
392
393unsigned int jiffies_to_usecs(const unsigned long j)
394{
395 /*
396 * Hz usually doesn't go much further MSEC_PER_SEC.
397 * jiffies_to_usecs() and usecs_to_jiffies() depend on that.
398 */
399 BUILD_BUG_ON(HZ > USEC_PER_SEC);
400
401#if !(USEC_PER_SEC % HZ)
402 return (USEC_PER_SEC / HZ) * j;
403#else
404# if BITS_PER_LONG == 32
405 return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
406# else
407 return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
408# endif
409#endif
410}
411EXPORT_SYMBOL(jiffies_to_usecs);
412
413/*
414 * mktime64 - Converts date to seconds.
415 * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
416 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
417 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
418 *
419 * [For the Julian calendar (which was used in Russia before 1917,
420 * Britain & colonies before 1752, anywhere else before 1582,
421 * and is still in use by some communities) leave out the
422 * -year/100+year/400 terms, and add 10.]
423 *
424 * This algorithm was first published by Gauss (I think).
425 *
426 * A leap second can be indicated by calling this function with sec as
427 * 60 (allowable under ISO 8601). The leap second is treated the same
428 * as the following second since they don't exist in UNIX time.
429 *
430 * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight
431 * tomorrow - (allowable under ISO 8601) is supported.
432 */
433time64_t mktime64(const unsigned int year0, const unsigned int mon0,
434 const unsigned int day, const unsigned int hour,
435 const unsigned int min, const unsigned int sec)
436{
437 unsigned int mon = mon0, year = year0;
438
439 /* 1..12 -> 11,12,1..10 */
440 if (0 >= (int) (mon -= 2)) {
441 mon += 12; /* Puts Feb last since it has leap day */
442 year -= 1;
443 }
444
445 return ((((time64_t)
446 (year/4 - year/100 + year/400 + 367*mon/12 + day) +
447 year*365 - 719499
448 )*24 + hour /* now have hours - midnight tomorrow handled here */
449 )*60 + min /* now have minutes */
450 )*60 + sec; /* finally seconds */
451}
452EXPORT_SYMBOL(mktime64);
453
454/**
455 * ns_to_timespec - Convert nanoseconds to timespec
456 * @nsec: the nanoseconds value to be converted
457 *
458 * Returns the timespec representation of the nsec parameter.
459 */
460struct timespec ns_to_timespec(const s64 nsec)
461{
462 struct timespec ts;
463 s32 rem;
464
465 if (!nsec)
466 return (struct timespec) {0, 0};
467
468 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
469 if (unlikely(rem < 0)) {
470 ts.tv_sec--;
471 rem += NSEC_PER_SEC;
472 }
473 ts.tv_nsec = rem;
474
475 return ts;
476}
477EXPORT_SYMBOL(ns_to_timespec);
478
479/**
480 * ns_to_timeval - Convert nanoseconds to timeval
481 * @nsec: the nanoseconds value to be converted
482 *
483 * Returns the timeval representation of the nsec parameter.
484 */
485struct timeval ns_to_timeval(const s64 nsec)
486{
487 struct timespec ts = ns_to_timespec(nsec);
488 struct timeval tv;
489
490 tv.tv_sec = ts.tv_sec;
491 tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000;
492
493 return tv;
494}
495EXPORT_SYMBOL(ns_to_timeval);
496
497struct __kernel_old_timeval ns_to_kernel_old_timeval(const s64 nsec)
498{
499 struct timespec64 ts = ns_to_timespec64(nsec);
500 struct __kernel_old_timeval tv;
501
502 tv.tv_sec = ts.tv_sec;
503 tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000;
504
505 return tv;
506}
507EXPORT_SYMBOL(ns_to_kernel_old_timeval);
508
509/**
510 * set_normalized_timespec - set timespec sec and nsec parts and normalize
511 *
512 * @ts: pointer to timespec variable to be set
513 * @sec: seconds to set
514 * @nsec: nanoseconds to set
515 *
516 * Set seconds and nanoseconds field of a timespec variable and
517 * normalize to the timespec storage format
518 *
519 * Note: The tv_nsec part is always in the range of
520 * 0 <= tv_nsec < NSEC_PER_SEC
521 * For negative values only the tv_sec field is negative !
522 */
523void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
524{
525 while (nsec >= NSEC_PER_SEC) {
526 /*
527 * The following asm() prevents the compiler from
528 * optimising this loop into a modulo operation. See
529 * also __iter_div_u64_rem() in include/linux/time.h
530 */
531 asm("" : "+rm"(nsec));
532 nsec -= NSEC_PER_SEC;
533 ++sec;
534 }
535 while (nsec < 0) {
536 asm("" : "+rm"(nsec));
537 nsec += NSEC_PER_SEC;
538 --sec;
539 }
540 ts->tv_sec = sec;
541 ts->tv_nsec = nsec;
542}
543EXPORT_SYMBOL(set_normalized_timespec64);
544
545/**
546 * ns_to_timespec64 - Convert nanoseconds to timespec64
547 * @nsec: the nanoseconds value to be converted
548 *
549 * Returns the timespec64 representation of the nsec parameter.
550 */
551struct timespec64 ns_to_timespec64(const s64 nsec)
552{
553 struct timespec64 ts;
554 s32 rem;
555
556 if (!nsec)
557 return (struct timespec64) {0, 0};
558
559 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
560 if (unlikely(rem < 0)) {
561 ts.tv_sec--;
562 rem += NSEC_PER_SEC;
563 }
564 ts.tv_nsec = rem;
565
566 return ts;
567}
568EXPORT_SYMBOL(ns_to_timespec64);
569
570/**
571 * msecs_to_jiffies: - convert milliseconds to jiffies
572 * @m: time in milliseconds
573 *
574 * conversion is done as follows:
575 *
576 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
577 *
578 * - 'too large' values [that would result in larger than
579 * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
580 *
581 * - all other values are converted to jiffies by either multiplying
582 * the input value by a factor or dividing it with a factor and
583 * handling any 32-bit overflows.
584 * for the details see __msecs_to_jiffies()
585 *
586 * msecs_to_jiffies() checks for the passed in value being a constant
587 * via __builtin_constant_p() allowing gcc to eliminate most of the
588 * code, __msecs_to_jiffies() is called if the value passed does not
589 * allow constant folding and the actual conversion must be done at
590 * runtime.
591 * the _msecs_to_jiffies helpers are the HZ dependent conversion
592 * routines found in include/linux/jiffies.h
593 */
594unsigned long __msecs_to_jiffies(const unsigned int m)
595{
596 /*
597 * Negative value, means infinite timeout:
598 */
599 if ((int)m < 0)
600 return MAX_JIFFY_OFFSET;
601 return _msecs_to_jiffies(m);
602}
603EXPORT_SYMBOL(__msecs_to_jiffies);
604
605unsigned long __usecs_to_jiffies(const unsigned int u)
606{
607 if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
608 return MAX_JIFFY_OFFSET;
609 return _usecs_to_jiffies(u);
610}
611EXPORT_SYMBOL(__usecs_to_jiffies);
612
613/*
614 * The TICK_NSEC - 1 rounds up the value to the next resolution. Note
615 * that a remainder subtract here would not do the right thing as the
616 * resolution values don't fall on second boundries. I.e. the line:
617 * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
618 * Note that due to the small error in the multiplier here, this
619 * rounding is incorrect for sufficiently large values of tv_nsec, but
620 * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're
621 * OK.
622 *
623 * Rather, we just shift the bits off the right.
624 *
625 * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
626 * value to a scaled second value.
627 */
628static unsigned long
629__timespec64_to_jiffies(u64 sec, long nsec)
630{
631 nsec = nsec + TICK_NSEC - 1;
632
633 if (sec >= MAX_SEC_IN_JIFFIES){
634 sec = MAX_SEC_IN_JIFFIES;
635 nsec = 0;
636 }
637 return ((sec * SEC_CONVERSION) +
638 (((u64)nsec * NSEC_CONVERSION) >>
639 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
640
641}
642
643static unsigned long
644__timespec_to_jiffies(unsigned long sec, long nsec)
645{
646 return __timespec64_to_jiffies((u64)sec, nsec);
647}
648
649unsigned long
650timespec64_to_jiffies(const struct timespec64 *value)
651{
652 return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec);
653}
654EXPORT_SYMBOL(timespec64_to_jiffies);
655
656void
657jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
658{
659 /*
660 * Convert jiffies to nanoseconds and separate with
661 * one divide.
662 */
663 u32 rem;
664 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
665 NSEC_PER_SEC, &rem);
666 value->tv_nsec = rem;
667}
668EXPORT_SYMBOL(jiffies_to_timespec64);
669
670/*
671 * We could use a similar algorithm to timespec_to_jiffies (with a
672 * different multiplier for usec instead of nsec). But this has a
673 * problem with rounding: we can't exactly add TICK_NSEC - 1 to the
674 * usec value, since it's not necessarily integral.
675 *
676 * We could instead round in the intermediate scaled representation
677 * (i.e. in units of 1/2^(large scale) jiffies) but that's also
678 * perilous: the scaling introduces a small positive error, which
679 * combined with a division-rounding-upward (i.e. adding 2^(scale) - 1
680 * units to the intermediate before shifting) leads to accidental
681 * overflow and overestimates.
682 *
683 * At the cost of one additional multiplication by a constant, just
684 * use the timespec implementation.
685 */
686unsigned long
687timeval_to_jiffies(const struct timeval *value)
688{
689 return __timespec_to_jiffies(value->tv_sec,
690 value->tv_usec * NSEC_PER_USEC);
691}
692EXPORT_SYMBOL(timeval_to_jiffies);
693
694void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
695{
696 /*
697 * Convert jiffies to nanoseconds and separate with
698 * one divide.
699 */
700 u32 rem;
701
702 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
703 NSEC_PER_SEC, &rem);
704 value->tv_usec = rem / NSEC_PER_USEC;
705}
706EXPORT_SYMBOL(jiffies_to_timeval);
707
708/*
709 * Convert jiffies/jiffies_64 to clock_t and back.
710 */
711clock_t jiffies_to_clock_t(unsigned long x)
712{
713#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
714# if HZ < USER_HZ
715 return x * (USER_HZ / HZ);
716# else
717 return x / (HZ / USER_HZ);
718# endif
719#else
720 return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
721#endif
722}
723EXPORT_SYMBOL(jiffies_to_clock_t);
724
725unsigned long clock_t_to_jiffies(unsigned long x)
726{
727#if (HZ % USER_HZ)==0
728 if (x >= ~0UL / (HZ / USER_HZ))
729 return ~0UL;
730 return x * (HZ / USER_HZ);
731#else
732 /* Don't worry about loss of precision here .. */
733 if (x >= ~0UL / HZ * USER_HZ)
734 return ~0UL;
735
736 /* .. but do try to contain it here */
737 return div_u64((u64)x * HZ, USER_HZ);
738#endif
739}
740EXPORT_SYMBOL(clock_t_to_jiffies);
741
742u64 jiffies_64_to_clock_t(u64 x)
743{
744#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
745# if HZ < USER_HZ
746 x = div_u64(x * USER_HZ, HZ);
747# elif HZ > USER_HZ
748 x = div_u64(x, HZ / USER_HZ);
749# else
750 /* Nothing to do */
751# endif
752#else
753 /*
754 * There are better ways that don't overflow early,
755 * but even this doesn't overflow in hundreds of years
756 * in 64 bits, so..
757 */
758 x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
759#endif
760 return x;
761}
762EXPORT_SYMBOL(jiffies_64_to_clock_t);
763
764u64 nsec_to_clock_t(u64 x)
765{
766#if (NSEC_PER_SEC % USER_HZ) == 0
767 return div_u64(x, NSEC_PER_SEC / USER_HZ);
768#elif (USER_HZ % 512) == 0
769 return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
770#else
771 /*
772 * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
773 * overflow after 64.99 years.
774 * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
775 */
776 return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
777#endif
778}
779
780u64 jiffies64_to_nsecs(u64 j)
781{
782#if !(NSEC_PER_SEC % HZ)
783 return (NSEC_PER_SEC / HZ) * j;
784# else
785 return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN);
786#endif
787}
788EXPORT_SYMBOL(jiffies64_to_nsecs);
789
790u64 jiffies64_to_msecs(const u64 j)
791{
792#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
793 return (MSEC_PER_SEC / HZ) * j;
794#else
795 return div_u64(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
796#endif
797}
798EXPORT_SYMBOL(jiffies64_to_msecs);
799
800/**
801 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
802 *
803 * @n: nsecs in u64
804 *
805 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
806 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
807 * for scheduler, not for use in device drivers to calculate timeout value.
808 *
809 * note:
810 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
811 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
812 */
813u64 nsecs_to_jiffies64(u64 n)
814{
815#if (NSEC_PER_SEC % HZ) == 0
816 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
817 return div_u64(n, NSEC_PER_SEC / HZ);
818#elif (HZ % 512) == 0
819 /* overflow after 292 years if HZ = 1024 */
820 return div_u64(n * HZ / 512, NSEC_PER_SEC / 512);
821#else
822 /*
823 * Generic case - optimized for cases where HZ is a multiple of 3.
824 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc.
825 */
826 return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ);
827#endif
828}
829EXPORT_SYMBOL(nsecs_to_jiffies64);
830
831/**
832 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
833 *
834 * @n: nsecs in u64
835 *
836 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
837 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
838 * for scheduler, not for use in device drivers to calculate timeout value.
839 *
840 * note:
841 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
842 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
843 */
844unsigned long nsecs_to_jiffies(u64 n)
845{
846 return (unsigned long)nsecs_to_jiffies64(n);
847}
848EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
849
850/*
851 * Add two timespec64 values and do a safety check for overflow.
852 * It's assumed that both values are valid (>= 0).
853 * And, each timespec64 is in normalized form.
854 */
855struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
856 const struct timespec64 rhs)
857{
858 struct timespec64 res;
859
860 set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
861 lhs.tv_nsec + rhs.tv_nsec);
862
863 if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
864 res.tv_sec = TIME64_MAX;
865 res.tv_nsec = 0;
866 }
867
868 return res;
869}
870
871int 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 for 32 bit systems or in compat mode */
884 if (IS_ENABLED(CONFIG_64BIT_TIME) && in_compat_syscall())
885 kts.tv_nsec &= 0xFFFFFFFFUL;
886
887 ts->tv_nsec = kts.tv_nsec;
888
889 return 0;
890}
891EXPORT_SYMBOL_GPL(get_timespec64);
892
893int put_timespec64(const struct timespec64 *ts,
894 struct __kernel_timespec __user *uts)
895{
896 struct __kernel_timespec kts = {
897 .tv_sec = ts->tv_sec,
898 .tv_nsec = ts->tv_nsec
899 };
900
901 return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0;
902}
903EXPORT_SYMBOL_GPL(put_timespec64);
904
905static int __get_old_timespec32(struct timespec64 *ts64,
906 const struct old_timespec32 __user *cts)
907{
908 struct old_timespec32 ts;
909 int ret;
910
911 ret = copy_from_user(&ts, cts, sizeof(ts));
912 if (ret)
913 return -EFAULT;
914
915 ts64->tv_sec = ts.tv_sec;
916 ts64->tv_nsec = ts.tv_nsec;
917
918 return 0;
919}
920
921static int __put_old_timespec32(const struct timespec64 *ts64,
922 struct old_timespec32 __user *cts)
923{
924 struct old_timespec32 ts = {
925 .tv_sec = ts64->tv_sec,
926 .tv_nsec = ts64->tv_nsec
927 };
928 return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0;
929}
930
931int get_old_timespec32(struct timespec64 *ts, const void __user *uts)
932{
933 if (COMPAT_USE_64BIT_TIME)
934 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
935 else
936 return __get_old_timespec32(ts, uts);
937}
938EXPORT_SYMBOL_GPL(get_old_timespec32);
939
940int put_old_timespec32(const struct timespec64 *ts, void __user *uts)
941{
942 if (COMPAT_USE_64BIT_TIME)
943 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
944 else
945 return __put_old_timespec32(ts, uts);
946}
947EXPORT_SYMBOL_GPL(put_old_timespec32);
948
949int get_itimerspec64(struct itimerspec64 *it,
950 const struct __kernel_itimerspec __user *uit)
951{
952 int ret;
953
954 ret = get_timespec64(&it->it_interval, &uit->it_interval);
955 if (ret)
956 return ret;
957
958 ret = get_timespec64(&it->it_value, &uit->it_value);
959
960 return ret;
961}
962EXPORT_SYMBOL_GPL(get_itimerspec64);
963
964int put_itimerspec64(const struct itimerspec64 *it,
965 struct __kernel_itimerspec __user *uit)
966{
967 int ret;
968
969 ret = put_timespec64(&it->it_interval, &uit->it_interval);
970 if (ret)
971 return ret;
972
973 ret = put_timespec64(&it->it_value, &uit->it_value);
974
975 return ret;
976}
977EXPORT_SYMBOL_GPL(put_itimerspec64);
978
979int get_old_itimerspec32(struct itimerspec64 *its,
980 const struct old_itimerspec32 __user *uits)
981{
982
983 if (__get_old_timespec32(&its->it_interval, &uits->it_interval) ||
984 __get_old_timespec32(&its->it_value, &uits->it_value))
985 return -EFAULT;
986 return 0;
987}
988EXPORT_SYMBOL_GPL(get_old_itimerspec32);
989
990int put_old_itimerspec32(const struct itimerspec64 *its,
991 struct old_itimerspec32 __user *uits)
992{
993 if (__put_old_timespec32(&its->it_interval, &uits->it_interval) ||
994 __put_old_timespec32(&its->it_value, &uits->it_value))
995 return -EFAULT;
996 return 0;
997}
998EXPORT_SYMBOL_GPL(put_old_itimerspec32);
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/timex.h>
32#include <linux/capability.h>
33#include <linux/timekeeper_internal.h>
34#include <linux/errno.h>
35#include <linux/syscalls.h>
36#include <linux/security.h>
37#include <linux/fs.h>
38#include <linux/math64.h>
39#include <linux/ptrace.h>
40
41#include <linux/uaccess.h>
42#include <linux/compat.h>
43#include <asm/unistd.h>
44
45#include <generated/timeconst.h>
46#include "timekeeping.h"
47
48/*
49 * The timezone where the local system is located. Used as a default by some
50 * programs who obtain this value by using gettimeofday.
51 */
52struct timezone sys_tz;
53
54EXPORT_SYMBOL(sys_tz);
55
56#ifdef __ARCH_WANT_SYS_TIME
57
58/*
59 * sys_time() can be implemented in user-level using
60 * sys_gettimeofday(). Is this for backwards compatibility? If so,
61 * why not move it into the appropriate arch directory (for those
62 * architectures that need it).
63 */
64SYSCALL_DEFINE1(time, time_t __user *, tloc)
65{
66 time_t i = get_seconds();
67
68 if (tloc) {
69 if (put_user(i,tloc))
70 return -EFAULT;
71 }
72 force_successful_syscall_return();
73 return i;
74}
75
76/*
77 * sys_stime() can be implemented in user-level using
78 * sys_settimeofday(). Is this for backwards compatibility? If so,
79 * why not move it into the appropriate arch directory (for those
80 * architectures that need it).
81 */
82
83SYSCALL_DEFINE1(stime, time_t __user *, tptr)
84{
85 struct timespec64 tv;
86 int err;
87
88 if (get_user(tv.tv_sec, tptr))
89 return -EFAULT;
90
91 tv.tv_nsec = 0;
92
93 err = security_settime64(&tv, NULL);
94 if (err)
95 return err;
96
97 do_settimeofday64(&tv);
98 return 0;
99}
100
101#endif /* __ARCH_WANT_SYS_TIME */
102
103#ifdef CONFIG_COMPAT
104#ifdef __ARCH_WANT_COMPAT_SYS_TIME
105
106/* compat_time_t is a 32 bit "long" and needs to get converted. */
107COMPAT_SYSCALL_DEFINE1(time, compat_time_t __user *, tloc)
108{
109 struct timeval tv;
110 compat_time_t i;
111
112 do_gettimeofday(&tv);
113 i = tv.tv_sec;
114
115 if (tloc) {
116 if (put_user(i,tloc))
117 return -EFAULT;
118 }
119 force_successful_syscall_return();
120 return i;
121}
122
123COMPAT_SYSCALL_DEFINE1(stime, compat_time_t __user *, tptr)
124{
125 struct timespec64 tv;
126 int err;
127
128 if (get_user(tv.tv_sec, tptr))
129 return -EFAULT;
130
131 tv.tv_nsec = 0;
132
133 err = security_settime64(&tv, NULL);
134 if (err)
135 return err;
136
137 do_settimeofday64(&tv);
138 return 0;
139}
140
141#endif /* __ARCH_WANT_COMPAT_SYS_TIME */
142#endif
143
144SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv,
145 struct timezone __user *, tz)
146{
147 if (likely(tv != NULL)) {
148 struct timeval ktv;
149 do_gettimeofday(&ktv);
150 if (copy_to_user(tv, &ktv, sizeof(ktv)))
151 return -EFAULT;
152 }
153 if (unlikely(tz != NULL)) {
154 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
155 return -EFAULT;
156 }
157 return 0;
158}
159
160/*
161 * In case for some reason the CMOS clock has not already been running
162 * in UTC, but in some local time: The first time we set the timezone,
163 * we will warp the clock so that it is ticking UTC time instead of
164 * local time. Presumably, if someone is setting the timezone then we
165 * are running in an environment where the programs understand about
166 * timezones. This should be done at boot time in the /etc/rc script,
167 * as soon as possible, so that the clock can be set right. Otherwise,
168 * various programs will get confused when the clock gets warped.
169 */
170
171int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz)
172{
173 static int firsttime = 1;
174 int error = 0;
175
176 if (tv && !timespec64_valid(tv))
177 return -EINVAL;
178
179 error = security_settime64(tv, tz);
180 if (error)
181 return error;
182
183 if (tz) {
184 /* Verify we're witin the +-15 hrs range */
185 if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60)
186 return -EINVAL;
187
188 sys_tz = *tz;
189 update_vsyscall_tz();
190 if (firsttime) {
191 firsttime = 0;
192 if (!tv)
193 timekeeping_warp_clock();
194 }
195 }
196 if (tv)
197 return do_settimeofday64(tv);
198 return 0;
199}
200
201SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
202 struct timezone __user *, tz)
203{
204 struct timespec64 new_ts;
205 struct timeval user_tv;
206 struct timezone new_tz;
207
208 if (tv) {
209 if (copy_from_user(&user_tv, tv, sizeof(*tv)))
210 return -EFAULT;
211
212 if (!timeval_valid(&user_tv))
213 return -EINVAL;
214
215 new_ts.tv_sec = user_tv.tv_sec;
216 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
217 }
218 if (tz) {
219 if (copy_from_user(&new_tz, tz, sizeof(*tz)))
220 return -EFAULT;
221 }
222
223 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
224}
225
226#ifdef CONFIG_COMPAT
227COMPAT_SYSCALL_DEFINE2(gettimeofday, struct compat_timeval __user *, tv,
228 struct timezone __user *, tz)
229{
230 if (tv) {
231 struct timeval ktv;
232
233 do_gettimeofday(&ktv);
234 if (compat_put_timeval(&ktv, tv))
235 return -EFAULT;
236 }
237 if (tz) {
238 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
239 return -EFAULT;
240 }
241
242 return 0;
243}
244
245COMPAT_SYSCALL_DEFINE2(settimeofday, struct compat_timeval __user *, tv,
246 struct timezone __user *, tz)
247{
248 struct timespec64 new_ts;
249 struct timeval user_tv;
250 struct timezone new_tz;
251
252 if (tv) {
253 if (compat_get_timeval(&user_tv, tv))
254 return -EFAULT;
255 new_ts.tv_sec = user_tv.tv_sec;
256 new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
257 }
258 if (tz) {
259 if (copy_from_user(&new_tz, tz, sizeof(*tz)))
260 return -EFAULT;
261 }
262
263 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
264}
265#endif
266
267SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p)
268{
269 struct timex txc; /* Local copy of parameter */
270 int ret;
271
272 /* Copy the user data space into the kernel copy
273 * structure. But bear in mind that the structures
274 * may change
275 */
276 if (copy_from_user(&txc, txc_p, sizeof(struct timex)))
277 return -EFAULT;
278 ret = do_adjtimex(&txc);
279 return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
280}
281
282#ifdef CONFIG_COMPAT
283
284COMPAT_SYSCALL_DEFINE1(adjtimex, struct compat_timex __user *, utp)
285{
286 struct timex txc;
287 int err, ret;
288
289 err = compat_get_timex(&txc, utp);
290 if (err)
291 return err;
292
293 ret = do_adjtimex(&txc);
294
295 err = compat_put_timex(utp, &txc);
296 if (err)
297 return err;
298
299 return ret;
300}
301#endif
302
303/*
304 * Convert jiffies to milliseconds and back.
305 *
306 * Avoid unnecessary multiplications/divisions in the
307 * two most common HZ cases:
308 */
309unsigned int jiffies_to_msecs(const unsigned long j)
310{
311#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
312 return (MSEC_PER_SEC / HZ) * j;
313#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
314 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
315#else
316# if BITS_PER_LONG == 32
317 return (HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
318# else
319 return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
320# endif
321#endif
322}
323EXPORT_SYMBOL(jiffies_to_msecs);
324
325unsigned 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}
343EXPORT_SYMBOL(jiffies_to_usecs);
344
345/**
346 * timespec_trunc - Truncate timespec to a granularity
347 * @t: Timespec
348 * @gran: Granularity in ns.
349 *
350 * Truncate a timespec to a granularity. Always rounds down. gran must
351 * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
352 */
353struct timespec timespec_trunc(struct timespec t, unsigned gran)
354{
355 /* Avoid division in the common cases 1 ns and 1 s. */
356 if (gran == 1) {
357 /* nothing */
358 } else if (gran == NSEC_PER_SEC) {
359 t.tv_nsec = 0;
360 } else if (gran > 1 && gran < NSEC_PER_SEC) {
361 t.tv_nsec -= t.tv_nsec % gran;
362 } else {
363 WARN(1, "illegal file time granularity: %u", gran);
364 }
365 return t;
366}
367EXPORT_SYMBOL(timespec_trunc);
368
369/*
370 * mktime64 - Converts date to seconds.
371 * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
372 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
373 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
374 *
375 * [For the Julian calendar (which was used in Russia before 1917,
376 * Britain & colonies before 1752, anywhere else before 1582,
377 * and is still in use by some communities) leave out the
378 * -year/100+year/400 terms, and add 10.]
379 *
380 * This algorithm was first published by Gauss (I think).
381 *
382 * A leap second can be indicated by calling this function with sec as
383 * 60 (allowable under ISO 8601). The leap second is treated the same
384 * as the following second since they don't exist in UNIX time.
385 *
386 * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight
387 * tomorrow - (allowable under ISO 8601) is supported.
388 */
389time64_t mktime64(const unsigned int year0, const unsigned int mon0,
390 const unsigned int day, const unsigned int hour,
391 const unsigned int min, const unsigned int sec)
392{
393 unsigned int mon = mon0, year = year0;
394
395 /* 1..12 -> 11,12,1..10 */
396 if (0 >= (int) (mon -= 2)) {
397 mon += 12; /* Puts Feb last since it has leap day */
398 year -= 1;
399 }
400
401 return ((((time64_t)
402 (year/4 - year/100 + year/400 + 367*mon/12 + day) +
403 year*365 - 719499
404 )*24 + hour /* now have hours - midnight tomorrow handled here */
405 )*60 + min /* now have minutes */
406 )*60 + sec; /* finally seconds */
407}
408EXPORT_SYMBOL(mktime64);
409
410#if __BITS_PER_LONG == 32
411/**
412 * set_normalized_timespec - set timespec sec and nsec parts and normalize
413 *
414 * @ts: pointer to timespec variable to be set
415 * @sec: seconds to set
416 * @nsec: nanoseconds to set
417 *
418 * Set seconds and nanoseconds field of a timespec variable and
419 * normalize to the timespec storage format
420 *
421 * Note: The tv_nsec part is always in the range of
422 * 0 <= tv_nsec < NSEC_PER_SEC
423 * For negative values only the tv_sec field is negative !
424 */
425void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec)
426{
427 while (nsec >= NSEC_PER_SEC) {
428 /*
429 * The following asm() prevents the compiler from
430 * optimising this loop into a modulo operation. See
431 * also __iter_div_u64_rem() in include/linux/time.h
432 */
433 asm("" : "+rm"(nsec));
434 nsec -= NSEC_PER_SEC;
435 ++sec;
436 }
437 while (nsec < 0) {
438 asm("" : "+rm"(nsec));
439 nsec += NSEC_PER_SEC;
440 --sec;
441 }
442 ts->tv_sec = sec;
443 ts->tv_nsec = nsec;
444}
445EXPORT_SYMBOL(set_normalized_timespec);
446
447/**
448 * ns_to_timespec - Convert nanoseconds to timespec
449 * @nsec: the nanoseconds value to be converted
450 *
451 * Returns the timespec representation of the nsec parameter.
452 */
453struct timespec ns_to_timespec(const s64 nsec)
454{
455 struct timespec ts;
456 s32 rem;
457
458 if (!nsec)
459 return (struct timespec) {0, 0};
460
461 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
462 if (unlikely(rem < 0)) {
463 ts.tv_sec--;
464 rem += NSEC_PER_SEC;
465 }
466 ts.tv_nsec = rem;
467
468 return ts;
469}
470EXPORT_SYMBOL(ns_to_timespec);
471#endif
472
473/**
474 * ns_to_timeval - Convert nanoseconds to timeval
475 * @nsec: the nanoseconds value to be converted
476 *
477 * Returns the timeval representation of the nsec parameter.
478 */
479struct timeval ns_to_timeval(const s64 nsec)
480{
481 struct timespec ts = ns_to_timespec(nsec);
482 struct timeval tv;
483
484 tv.tv_sec = ts.tv_sec;
485 tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000;
486
487 return tv;
488}
489EXPORT_SYMBOL(ns_to_timeval);
490
491struct __kernel_old_timeval ns_to_kernel_old_timeval(const s64 nsec)
492{
493 struct timespec64 ts = ns_to_timespec64(nsec);
494 struct __kernel_old_timeval tv;
495
496 tv.tv_sec = ts.tv_sec;
497 tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000;
498
499 return tv;
500}
501EXPORT_SYMBOL(ns_to_kernel_old_timeval);
502
503/**
504 * set_normalized_timespec - set timespec sec and nsec parts and normalize
505 *
506 * @ts: pointer to timespec variable to be set
507 * @sec: seconds to set
508 * @nsec: nanoseconds to set
509 *
510 * Set seconds and nanoseconds field of a timespec variable and
511 * normalize to the timespec storage format
512 *
513 * Note: The tv_nsec part is always in the range of
514 * 0 <= tv_nsec < NSEC_PER_SEC
515 * For negative values only the tv_sec field is negative !
516 */
517void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
518{
519 while (nsec >= NSEC_PER_SEC) {
520 /*
521 * The following asm() prevents the compiler from
522 * optimising this loop into a modulo operation. See
523 * also __iter_div_u64_rem() in include/linux/time.h
524 */
525 asm("" : "+rm"(nsec));
526 nsec -= NSEC_PER_SEC;
527 ++sec;
528 }
529 while (nsec < 0) {
530 asm("" : "+rm"(nsec));
531 nsec += NSEC_PER_SEC;
532 --sec;
533 }
534 ts->tv_sec = sec;
535 ts->tv_nsec = nsec;
536}
537EXPORT_SYMBOL(set_normalized_timespec64);
538
539/**
540 * ns_to_timespec64 - Convert nanoseconds to timespec64
541 * @nsec: the nanoseconds value to be converted
542 *
543 * Returns the timespec64 representation of the nsec parameter.
544 */
545struct timespec64 ns_to_timespec64(const s64 nsec)
546{
547 struct timespec64 ts;
548 s32 rem;
549
550 if (!nsec)
551 return (struct timespec64) {0, 0};
552
553 ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
554 if (unlikely(rem < 0)) {
555 ts.tv_sec--;
556 rem += NSEC_PER_SEC;
557 }
558 ts.tv_nsec = rem;
559
560 return ts;
561}
562EXPORT_SYMBOL(ns_to_timespec64);
563
564/**
565 * msecs_to_jiffies: - convert milliseconds to jiffies
566 * @m: time in milliseconds
567 *
568 * conversion is done as follows:
569 *
570 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
571 *
572 * - 'too large' values [that would result in larger than
573 * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
574 *
575 * - all other values are converted to jiffies by either multiplying
576 * the input value by a factor or dividing it with a factor and
577 * handling any 32-bit overflows.
578 * for the details see __msecs_to_jiffies()
579 *
580 * msecs_to_jiffies() checks for the passed in value being a constant
581 * via __builtin_constant_p() allowing gcc to eliminate most of the
582 * code, __msecs_to_jiffies() is called if the value passed does not
583 * allow constant folding and the actual conversion must be done at
584 * runtime.
585 * the _msecs_to_jiffies helpers are the HZ dependent conversion
586 * routines found in include/linux/jiffies.h
587 */
588unsigned long __msecs_to_jiffies(const unsigned int m)
589{
590 /*
591 * Negative value, means infinite timeout:
592 */
593 if ((int)m < 0)
594 return MAX_JIFFY_OFFSET;
595 return _msecs_to_jiffies(m);
596}
597EXPORT_SYMBOL(__msecs_to_jiffies);
598
599unsigned long __usecs_to_jiffies(const unsigned int u)
600{
601 if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
602 return MAX_JIFFY_OFFSET;
603 return _usecs_to_jiffies(u);
604}
605EXPORT_SYMBOL(__usecs_to_jiffies);
606
607/*
608 * The TICK_NSEC - 1 rounds up the value to the next resolution. Note
609 * that a remainder subtract here would not do the right thing as the
610 * resolution values don't fall on second boundries. I.e. the line:
611 * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
612 * Note that due to the small error in the multiplier here, this
613 * rounding is incorrect for sufficiently large values of tv_nsec, but
614 * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're
615 * OK.
616 *
617 * Rather, we just shift the bits off the right.
618 *
619 * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
620 * value to a scaled second value.
621 */
622static unsigned long
623__timespec64_to_jiffies(u64 sec, long nsec)
624{
625 nsec = nsec + TICK_NSEC - 1;
626
627 if (sec >= MAX_SEC_IN_JIFFIES){
628 sec = MAX_SEC_IN_JIFFIES;
629 nsec = 0;
630 }
631 return ((sec * SEC_CONVERSION) +
632 (((u64)nsec * NSEC_CONVERSION) >>
633 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
634
635}
636
637static unsigned long
638__timespec_to_jiffies(unsigned long sec, long nsec)
639{
640 return __timespec64_to_jiffies((u64)sec, nsec);
641}
642
643unsigned long
644timespec64_to_jiffies(const struct timespec64 *value)
645{
646 return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec);
647}
648EXPORT_SYMBOL(timespec64_to_jiffies);
649
650void
651jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
652{
653 /*
654 * Convert jiffies to nanoseconds and separate with
655 * one divide.
656 */
657 u32 rem;
658 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
659 NSEC_PER_SEC, &rem);
660 value->tv_nsec = rem;
661}
662EXPORT_SYMBOL(jiffies_to_timespec64);
663
664/*
665 * We could use a similar algorithm to timespec_to_jiffies (with a
666 * different multiplier for usec instead of nsec). But this has a
667 * problem with rounding: we can't exactly add TICK_NSEC - 1 to the
668 * usec value, since it's not necessarily integral.
669 *
670 * We could instead round in the intermediate scaled representation
671 * (i.e. in units of 1/2^(large scale) jiffies) but that's also
672 * perilous: the scaling introduces a small positive error, which
673 * combined with a division-rounding-upward (i.e. adding 2^(scale) - 1
674 * units to the intermediate before shifting) leads to accidental
675 * overflow and overestimates.
676 *
677 * At the cost of one additional multiplication by a constant, just
678 * use the timespec implementation.
679 */
680unsigned long
681timeval_to_jiffies(const struct timeval *value)
682{
683 return __timespec_to_jiffies(value->tv_sec,
684 value->tv_usec * NSEC_PER_USEC);
685}
686EXPORT_SYMBOL(timeval_to_jiffies);
687
688void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
689{
690 /*
691 * Convert jiffies to nanoseconds and separate with
692 * one divide.
693 */
694 u32 rem;
695
696 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
697 NSEC_PER_SEC, &rem);
698 value->tv_usec = rem / NSEC_PER_USEC;
699}
700EXPORT_SYMBOL(jiffies_to_timeval);
701
702/*
703 * Convert jiffies/jiffies_64 to clock_t and back.
704 */
705clock_t jiffies_to_clock_t(unsigned long x)
706{
707#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
708# if HZ < USER_HZ
709 return x * (USER_HZ / HZ);
710# else
711 return x / (HZ / USER_HZ);
712# endif
713#else
714 return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
715#endif
716}
717EXPORT_SYMBOL(jiffies_to_clock_t);
718
719unsigned long clock_t_to_jiffies(unsigned long x)
720{
721#if (HZ % USER_HZ)==0
722 if (x >= ~0UL / (HZ / USER_HZ))
723 return ~0UL;
724 return x * (HZ / USER_HZ);
725#else
726 /* Don't worry about loss of precision here .. */
727 if (x >= ~0UL / HZ * USER_HZ)
728 return ~0UL;
729
730 /* .. but do try to contain it here */
731 return div_u64((u64)x * HZ, USER_HZ);
732#endif
733}
734EXPORT_SYMBOL(clock_t_to_jiffies);
735
736u64 jiffies_64_to_clock_t(u64 x)
737{
738#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
739# if HZ < USER_HZ
740 x = div_u64(x * USER_HZ, HZ);
741# elif HZ > USER_HZ
742 x = div_u64(x, HZ / USER_HZ);
743# else
744 /* Nothing to do */
745# endif
746#else
747 /*
748 * There are better ways that don't overflow early,
749 * but even this doesn't overflow in hundreds of years
750 * in 64 bits, so..
751 */
752 x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
753#endif
754 return x;
755}
756EXPORT_SYMBOL(jiffies_64_to_clock_t);
757
758u64 nsec_to_clock_t(u64 x)
759{
760#if (NSEC_PER_SEC % USER_HZ) == 0
761 return div_u64(x, NSEC_PER_SEC / USER_HZ);
762#elif (USER_HZ % 512) == 0
763 return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
764#else
765 /*
766 * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
767 * overflow after 64.99 years.
768 * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
769 */
770 return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
771#endif
772}
773
774u64 jiffies64_to_nsecs(u64 j)
775{
776#if !(NSEC_PER_SEC % HZ)
777 return (NSEC_PER_SEC / HZ) * j;
778# else
779 return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN);
780#endif
781}
782EXPORT_SYMBOL(jiffies64_to_nsecs);
783
784/**
785 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
786 *
787 * @n: nsecs in u64
788 *
789 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
790 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
791 * for scheduler, not for use in device drivers to calculate timeout value.
792 *
793 * note:
794 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
795 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
796 */
797u64 nsecs_to_jiffies64(u64 n)
798{
799#if (NSEC_PER_SEC % HZ) == 0
800 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
801 return div_u64(n, NSEC_PER_SEC / HZ);
802#elif (HZ % 512) == 0
803 /* overflow after 292 years if HZ = 1024 */
804 return div_u64(n * HZ / 512, NSEC_PER_SEC / 512);
805#else
806 /*
807 * Generic case - optimized for cases where HZ is a multiple of 3.
808 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc.
809 */
810 return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ);
811#endif
812}
813EXPORT_SYMBOL(nsecs_to_jiffies64);
814
815/**
816 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
817 *
818 * @n: nsecs in u64
819 *
820 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
821 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
822 * for scheduler, not for use in device drivers to calculate timeout value.
823 *
824 * note:
825 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
826 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
827 */
828unsigned long nsecs_to_jiffies(u64 n)
829{
830 return (unsigned long)nsecs_to_jiffies64(n);
831}
832EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
833
834/*
835 * Add two timespec64 values and do a safety check for overflow.
836 * It's assumed that both values are valid (>= 0).
837 * And, each timespec64 is in normalized form.
838 */
839struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
840 const struct timespec64 rhs)
841{
842 struct timespec64 res;
843
844 set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
845 lhs.tv_nsec + rhs.tv_nsec);
846
847 if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
848 res.tv_sec = TIME64_MAX;
849 res.tv_nsec = 0;
850 }
851
852 return res;
853}
854
855int get_timespec64(struct timespec64 *ts,
856 const struct timespec __user *uts)
857{
858 struct timespec kts;
859 int ret;
860
861 ret = copy_from_user(&kts, uts, sizeof(kts));
862 if (ret)
863 return -EFAULT;
864
865 ts->tv_sec = kts.tv_sec;
866 ts->tv_nsec = kts.tv_nsec;
867
868 return 0;
869}
870EXPORT_SYMBOL_GPL(get_timespec64);
871
872int put_timespec64(const struct timespec64 *ts,
873 struct timespec __user *uts)
874{
875 struct timespec kts = {
876 .tv_sec = ts->tv_sec,
877 .tv_nsec = ts->tv_nsec
878 };
879 return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0;
880}
881EXPORT_SYMBOL_GPL(put_timespec64);
882
883int get_itimerspec64(struct itimerspec64 *it,
884 const struct itimerspec __user *uit)
885{
886 int ret;
887
888 ret = get_timespec64(&it->it_interval, &uit->it_interval);
889 if (ret)
890 return ret;
891
892 ret = get_timespec64(&it->it_value, &uit->it_value);
893
894 return ret;
895}
896EXPORT_SYMBOL_GPL(get_itimerspec64);
897
898int put_itimerspec64(const struct itimerspec64 *it,
899 struct itimerspec __user *uit)
900{
901 int ret;
902
903 ret = put_timespec64(&it->it_interval, &uit->it_interval);
904 if (ret)
905 return ret;
906
907 ret = put_timespec64(&it->it_value, &uit->it_value);
908
909 return ret;
910}
911EXPORT_SYMBOL_GPL(put_itimerspec64);