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, __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
 81SYSCALL_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. */
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 __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
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 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
199SYSCALL_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
224COMPAT_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
243COMPAT_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
269SYSCALL_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
286int 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
318int 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
349SYSCALL_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 */
374unsigned 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}
389EXPORT_SYMBOL(jiffies_to_msecs);
390
391unsigned 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}
409EXPORT_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 */
431time64_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}
450EXPORT_SYMBOL(mktime64);
451
452struct __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}
462EXPORT_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 */
478void 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}
498EXPORT_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 */
506struct 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}
526EXPORT_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 */
552unsigned 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}
561EXPORT_SYMBOL(__msecs_to_jiffies);
562
563unsigned 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}
569EXPORT_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
587unsigned long
588timespec64_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}
602EXPORT_SYMBOL(timespec64_to_jiffies);
603
604void
605jiffies_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}
616EXPORT_SYMBOL(jiffies_to_timespec64);
617
618/*
619 * Convert jiffies/jiffies_64 to clock_t and back.
620 */
621clock_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}
633EXPORT_SYMBOL(jiffies_to_clock_t);
634
635unsigned 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}
650EXPORT_SYMBOL(clock_t_to_jiffies);
651
652u64 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}
672EXPORT_SYMBOL(jiffies_64_to_clock_t);
673
674u64 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
690u64 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}
698EXPORT_SYMBOL(jiffies64_to_nsecs);
699
700u64 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}
708EXPORT_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 */
723u64 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}
739EXPORT_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 */
754unsigned long nsecs_to_jiffies(u64 n)
755{
756	return (unsigned long)nsecs_to_jiffies64(n);
757}
758EXPORT_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 */
765struct 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
781int 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}
802EXPORT_SYMBOL_GPL(get_timespec64);
803
804int 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}
814EXPORT_SYMBOL_GPL(put_timespec64);
815
816static 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
832static 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
842int 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}
849EXPORT_SYMBOL_GPL(get_old_timespec32);
850
851int 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}
858EXPORT_SYMBOL_GPL(put_old_timespec32);
859
860int 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}
873EXPORT_SYMBOL_GPL(get_itimerspec64);
874
875int 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}
888EXPORT_SYMBOL_GPL(put_itimerspec64);
889
890int 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}
899EXPORT_SYMBOL_GPL(get_old_itimerspec32);
900
901int 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}
909EXPORT_SYMBOL_GPL(put_old_itimerspec32);