1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 *
5 * This file contains the interface functions for the various time related
6 * system calls: time, stime, gettimeofday, settimeofday, adjtime
7 *
8 * Modification history:
9 *
10 * 1993-09-02 Philip Gladstone
11 * Created file with time related functions from sched/core.c and adjtimex()
12 * 1993-10-08 Torsten Duwe
13 * adjtime interface update and CMOS clock write code
14 * 1995-08-13 Torsten Duwe
15 * kernel PLL updated to 1994-12-13 specs (rfc-1589)
16 * 1999-01-16 Ulrich Windl
17 * Introduced error checking for many cases in adjtimex().
18 * Updated NTP code according to technical memorandum Jan '96
19 * "A Kernel Model for Precision Timekeeping" by Dave Mills
20 * Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10)
21 * (Even though the technical memorandum forbids it)
22 * 2004-07-14 Christoph Lameter
23 * Added getnstimeofday to allow the posix timer functions to return
24 * with nanosecond accuracy
25 */
26
27 #include <linux/export.h>
28 #include <linux/kernel.h>
29 #include <linux/timex.h>
30 #include <linux/capability.h>
31 #include <linux/timekeeper_internal.h>
32 #include <linux/errno.h>
33 #include <linux/syscalls.h>
34 #include <linux/security.h>
35 #include <linux/fs.h>
36 #include <linux/math64.h>
37 #include <linux/ptrace.h>
38
39 #include <linux/uaccess.h>
40 #include <linux/compat.h>
41 #include <asm/unistd.h>
42
43 #include <generated/timeconst.h>
44 #include "timekeeping.h"
45
46 /*
47 * The timezone where the local system is located. Used as a default by some
48 * programs who obtain this value by using gettimeofday.
49 */
50 struct timezone sys_tz;
51
52 EXPORT_SYMBOL(sys_tz);
53
54 #ifdef __ARCH_WANT_SYS_TIME
55
56 /*
57 * sys_time() can be implemented in user-level using
58 * sys_gettimeofday(). Is this for backwards compatibility? If so,
59 * why not move it into the appropriate arch directory (for those
60 * architectures that need it).
61 */
62 SYSCALL_DEFINE1(time, __kernel_old_time_t __user *, tloc)
63 {
64 __kernel_old_time_t i = (__kernel_old_time_t)ktime_get_real_seconds();
65
66 if (tloc) {
67 if (put_user(i,tloc))
68 return -EFAULT;
69 }
70 force_successful_syscall_return();
71 return i;
72 }
73
74 /*
75 * sys_stime() can be implemented in user-level using
76 * sys_settimeofday(). Is this for backwards compatibility? If so,
77 * why not move it into the appropriate arch directory (for those
78 * architectures that need it).
79 */
80
81 SYSCALL_DEFINE1(stime, __kernel_old_time_t __user *, tptr)
82 {
83 struct timespec64 tv;
84 int err;
85
86 if (get_user(tv.tv_sec, tptr))
87 return -EFAULT;
88
89 tv.tv_nsec = 0;
90
91 err = security_settime64(&tv, NULL);
92 if (err)
93 return err;
94
95 do_settimeofday64(&tv);
96 return 0;
97 }
98
99 #endif /* __ARCH_WANT_SYS_TIME */
100
101 #ifdef CONFIG_COMPAT_32BIT_TIME
102 #ifdef __ARCH_WANT_SYS_TIME32
103
104 /* old_time32_t is a 32 bit "long" and needs to get converted. */
105 SYSCALL_DEFINE1(time32, old_time32_t __user *, tloc)
106 {
107 old_time32_t i;
108
109 i = (old_time32_t)ktime_get_real_seconds();
110
111 if (tloc) {
112 if (put_user(i,tloc))
113 return -EFAULT;
114 }
115 force_successful_syscall_return();
116 return i;
117 }
118
119 SYSCALL_DEFINE1(stime32, old_time32_t __user *, tptr)
120 {
121 struct timespec64 tv;
122 int err;
123
124 if (get_user(tv.tv_sec, tptr))
125 return -EFAULT;
126
127 tv.tv_nsec = 0;
128
129 err = security_settime64(&tv, NULL);
130 if (err)
131 return err;
132
133 do_settimeofday64(&tv);
134 return 0;
135 }
136
137 #endif /* __ARCH_WANT_SYS_TIME32 */
138 #endif
139
140 SYSCALL_DEFINE2(gettimeofday, struct __kernel_old_timeval __user *, tv,
141 struct timezone __user *, tz)
142 {
143 if (likely(tv != NULL)) {
144 struct timespec64 ts;
145
146 ktime_get_real_ts64(&ts);
147 if (put_user(ts.tv_sec, &tv->tv_sec) ||
148 put_user(ts.tv_nsec / 1000, &tv->tv_usec))
149 return -EFAULT;
150 }
151 if (unlikely(tz != NULL)) {
152 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
153 return -EFAULT;
154 }
155 return 0;
156 }
157
158 /*
159 * In case for some reason the CMOS clock has not already been running
160 * in UTC, but in some local time: The first time we set the timezone,
161 * we will warp the clock so that it is ticking UTC time instead of
162 * local time. Presumably, if someone is setting the timezone then we
163 * are running in an environment where the programs understand about
164 * timezones. This should be done at boot time in the /etc/rc script,
165 * as soon as possible, so that the clock can be set right. Otherwise,
166 * various programs will get confused when the clock gets warped.
167 */
168
169 int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz)
170 {
171 static int firsttime = 1;
172 int error = 0;
173
174 if (tv && !timespec64_valid_settod(tv))
175 return -EINVAL;
176
177 error = security_settime64(tv, tz);
178 if (error)
179 return error;
180
181 if (tz) {
182 /* Verify we're within the +-15 hrs range */
183 if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60)
184 return -EINVAL;
185
186 sys_tz = *tz;
187 update_vsyscall_tz();
188 if (firsttime) {
189 firsttime = 0;
190 if (!tv)
191 timekeeping_warp_clock();
192 }
193 }
194 if (tv)
195 return do_settimeofday64(tv);
196 return 0;
197 }
198
199 SYSCALL_DEFINE2(settimeofday, struct __kernel_old_timeval __user *, tv,
200 struct timezone __user *, tz)
201 {
202 struct timespec64 new_ts;
203 struct timezone new_tz;
204
205 if (tv) {
206 if (get_user(new_ts.tv_sec, &tv->tv_sec) ||
207 get_user(new_ts.tv_nsec, &tv->tv_usec))
208 return -EFAULT;
209
210 if (new_ts.tv_nsec > USEC_PER_SEC || new_ts.tv_nsec < 0)
211 return -EINVAL;
212
213 new_ts.tv_nsec *= NSEC_PER_USEC;
214 }
215 if (tz) {
216 if (copy_from_user(&new_tz, tz, sizeof(*tz)))
217 return -EFAULT;
218 }
219
220 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
221 }
222
223 #ifdef CONFIG_COMPAT
224 COMPAT_SYSCALL_DEFINE2(gettimeofday, struct old_timeval32 __user *, tv,
225 struct timezone __user *, tz)
226 {
227 if (tv) {
228 struct timespec64 ts;
229
230 ktime_get_real_ts64(&ts);
231 if (put_user(ts.tv_sec, &tv->tv_sec) ||
232 put_user(ts.tv_nsec / 1000, &tv->tv_usec))
233 return -EFAULT;
234 }
235 if (tz) {
236 if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
237 return -EFAULT;
238 }
239
240 return 0;
241 }
242
243 COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv,
244 struct timezone __user *, tz)
245 {
246 struct timespec64 new_ts;
247 struct timezone new_tz;
248
249 if (tv) {
250 if (get_user(new_ts.tv_sec, &tv->tv_sec) ||
251 get_user(new_ts.tv_nsec, &tv->tv_usec))
252 return -EFAULT;
253
254 if (new_ts.tv_nsec > USEC_PER_SEC || new_ts.tv_nsec < 0)
255 return -EINVAL;
256
257 new_ts.tv_nsec *= NSEC_PER_USEC;
258 }
259 if (tz) {
260 if (copy_from_user(&new_tz, tz, sizeof(*tz)))
261 return -EFAULT;
262 }
263
264 return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
265 }
266 #endif
267
268 #ifdef CONFIG_64BIT
269 SYSCALL_DEFINE1(adjtimex, struct __kernel_timex __user *, txc_p)
270 {
271 struct __kernel_timex txc; /* Local copy of parameter */
272 int ret;
273
274 /* Copy the user data space into the kernel copy
275 * structure. But bear in mind that the structures
276 * may change
277 */
278 if (copy_from_user(&txc, txc_p, sizeof(struct __kernel_timex)))
279 return -EFAULT;
280 ret = do_adjtimex(&txc);
281 return copy_to_user(txc_p, &txc, sizeof(struct __kernel_timex)) ? -EFAULT : ret;
282 }
283 #endif
284
285 #ifdef CONFIG_COMPAT_32BIT_TIME
286 int get_old_timex32(struct __kernel_timex *txc, const struct old_timex32 __user *utp)
287 {
288 struct old_timex32 tx32;
289
290 memset(txc, 0, sizeof(struct __kernel_timex));
291 if (copy_from_user(&tx32, utp, sizeof(struct old_timex32)))
292 return -EFAULT;
293
294 txc->modes = tx32.modes;
295 txc->offset = tx32.offset;
296 txc->freq = tx32.freq;
297 txc->maxerror = tx32.maxerror;
298 txc->esterror = tx32.esterror;
299 txc->status = tx32.status;
300 txc->constant = tx32.constant;
301 txc->precision = tx32.precision;
302 txc->tolerance = tx32.tolerance;
303 txc->time.tv_sec = tx32.time.tv_sec;
304 txc->time.tv_usec = tx32.time.tv_usec;
305 txc->tick = tx32.tick;
306 txc->ppsfreq = tx32.ppsfreq;
307 txc->jitter = tx32.jitter;
308 txc->shift = tx32.shift;
309 txc->stabil = tx32.stabil;
310 txc->jitcnt = tx32.jitcnt;
311 txc->calcnt = tx32.calcnt;
312 txc->errcnt = tx32.errcnt;
313 txc->stbcnt = tx32.stbcnt;
314
315 return 0;
316 }
317
318 int put_old_timex32(struct old_timex32 __user *utp, const struct __kernel_timex *txc)
319 {
320 struct old_timex32 tx32;
321
322 memset(&tx32, 0, sizeof(struct old_timex32));
323 tx32.modes = txc->modes;
324 tx32.offset = txc->offset;
325 tx32.freq = txc->freq;
326 tx32.maxerror = txc->maxerror;
327 tx32.esterror = txc->esterror;
328 tx32.status = txc->status;
329 tx32.constant = txc->constant;
330 tx32.precision = txc->precision;
331 tx32.tolerance = txc->tolerance;
332 tx32.time.tv_sec = txc->time.tv_sec;
333 tx32.time.tv_usec = txc->time.tv_usec;
334 tx32.tick = txc->tick;
335 tx32.ppsfreq = txc->ppsfreq;
336 tx32.jitter = txc->jitter;
337 tx32.shift = txc->shift;
338 tx32.stabil = txc->stabil;
339 tx32.jitcnt = txc->jitcnt;
340 tx32.calcnt = txc->calcnt;
341 tx32.errcnt = txc->errcnt;
342 tx32.stbcnt = txc->stbcnt;
343 tx32.tai = txc->tai;
344 if (copy_to_user(utp, &tx32, sizeof(struct old_timex32)))
345 return -EFAULT;
346 return 0;
347 }
348
349 SYSCALL_DEFINE1(adjtimex_time32, struct old_timex32 __user *, utp)
350 {
351 struct __kernel_timex txc;
352 int err, ret;
353
354 err = get_old_timex32(&txc, utp);
355 if (err)
356 return err;
357
358 ret = do_adjtimex(&txc);
359
360 err = put_old_timex32(utp, &txc);
361 if (err)
362 return err;
363
364 return ret;
365 }
366 #endif
367
368 /**
369 * jiffies_to_msecs - Convert jiffies to milliseconds
370 * @j: jiffies value
371 *
372 * Avoid unnecessary multiplications/divisions in the
373 * two most common HZ cases.
374 *
375 * Return: milliseconds value
376 */
377 unsigned int jiffies_to_msecs(const unsigned long j)
378 {
379 #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
380 return (MSEC_PER_SEC / HZ) * j;
381 #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
382 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
383 #else
384 # if BITS_PER_LONG == 32
385 return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >>
386 HZ_TO_MSEC_SHR32;
387 # else
388 return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
389 # endif
390 #endif
391 }
392 EXPORT_SYMBOL(jiffies_to_msecs);
393
394 /**
395 * jiffies_to_usecs - Convert jiffies to microseconds
396 * @j: jiffies value
397 *
398 * Return: microseconds value
399 */
400 unsigned int jiffies_to_usecs(const unsigned long j)
401 {
402 /*
403 * Hz usually doesn't go much further MSEC_PER_SEC.
404 * jiffies_to_usecs() and usecs_to_jiffies() depend on that.
405 */
406 BUILD_BUG_ON(HZ > USEC_PER_SEC);
407
408 #if !(USEC_PER_SEC % HZ)
409 return (USEC_PER_SEC / HZ) * j;
410 #else
411 # if BITS_PER_LONG == 32
412 return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
413 # else
414 return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
415 # endif
416 #endif
417 }
418 EXPORT_SYMBOL(jiffies_to_usecs);
419
420 /**
421 * mktime64 - Converts date to seconds.
422 * @year0: year to convert
423 * @mon0: month to convert
424 * @day: day to convert
425 * @hour: hour to convert
426 * @min: minute to convert
427 * @sec: second to convert
428 *
429 * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
430 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
431 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
432 *
433 * [For the Julian calendar (which was used in Russia before 1917,
434 * Britain & colonies before 1752, anywhere else before 1582,
435 * and is still in use by some communities) leave out the
436 * -year/100+year/400 terms, and add 10.]
437 *
438 * This algorithm was first published by Gauss (I think).
439 *
440 * A leap second can be indicated by calling this function with sec as
441 * 60 (allowable under ISO 8601). The leap second is treated the same
442 * as the following second since they don't exist in UNIX time.
443 *
444 * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight
445 * tomorrow - (allowable under ISO 8601) is supported.
446 *
447 * Return: seconds since the epoch time for the given input date
448 */
449 time64_t mktime64(const unsigned int year0, const unsigned int mon0,
450 const unsigned int day, const unsigned int hour,
451 const unsigned int min, const unsigned int sec)
452 {
453 unsigned int mon = mon0, year = year0;
454
455 /* 1..12 -> 11,12,1..10 */
456 if (0 >= (int) (mon -= 2)) {
457 mon += 12; /* Puts Feb last since it has leap day */
458 year -= 1;
459 }
460
461 return ((((time64_t)
462 (year/4 - year/100 + year/400 + 367*mon/12 + day) +
463 year*365 - 719499
464 )*24 + hour /* now have hours - midnight tomorrow handled here */
465 )*60 + min /* now have minutes */
466 )*60 + sec; /* finally seconds */
467 }
468 EXPORT_SYMBOL(mktime64);
469
470 struct __kernel_old_timeval ns_to_kernel_old_timeval(s64 nsec)
471 {
472 struct timespec64 ts = ns_to_timespec64(nsec);
473 struct __kernel_old_timeval tv;
474
475 tv.tv_sec = ts.tv_sec;
476 tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000;
477
478 return tv;
479 }
480 EXPORT_SYMBOL(ns_to_kernel_old_timeval);
481
482 /**
483 * set_normalized_timespec64 - set timespec sec and nsec parts and normalize
484 *
485 * @ts: pointer to timespec variable to be set
486 * @sec: seconds to set
487 * @nsec: nanoseconds to set
488 *
489 * Set seconds and nanoseconds field of a timespec variable and
490 * normalize to the timespec storage format
491 *
492 * Note: The tv_nsec part is always in the range of 0 <= tv_nsec < NSEC_PER_SEC.
493 * For negative values only the tv_sec field is negative !
494 */
495 void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
496 {
497 while (nsec >= NSEC_PER_SEC) {
498 /*
499 * The following asm() prevents the compiler from
500 * optimising this loop into a modulo operation. See
501 * also __iter_div_u64_rem() in include/linux/time.h
502 */
503 asm("" : "+rm"(nsec));
504 nsec -= NSEC_PER_SEC;
505 ++sec;
506 }
507 while (nsec < 0) {
508 asm("" : "+rm"(nsec));
509 nsec += NSEC_PER_SEC;
510 --sec;
511 }
512 ts->tv_sec = sec;
513 ts->tv_nsec = nsec;
514 }
515 EXPORT_SYMBOL(set_normalized_timespec64);
516
517 /**
518 * ns_to_timespec64 - Convert nanoseconds to timespec64
519 * @nsec: the nanoseconds value to be converted
520 *
521 * Return: the timespec64 representation of the nsec parameter.
522 */
523 struct timespec64 ns_to_timespec64(s64 nsec)
524 {
525 struct timespec64 ts = { 0, 0 };
526 s32 rem;
527
528 if (likely(nsec > 0)) {
529 ts.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
530 ts.tv_nsec = rem;
531 } else if (nsec < 0) {
532 /*
533 * With negative times, tv_sec points to the earlier
534 * second, and tv_nsec counts the nanoseconds since
535 * then, so tv_nsec is always a positive number.
536 */
537 ts.tv_sec = -div_u64_rem(-nsec - 1, NSEC_PER_SEC, &rem) - 1;
538 ts.tv_nsec = NSEC_PER_SEC - rem - 1;
539 }
540
541 return ts;
542 }
543 EXPORT_SYMBOL(ns_to_timespec64);
544
545 /**
546 * __msecs_to_jiffies: - convert milliseconds to jiffies
547 * @m: time in milliseconds
548 *
549 * conversion is done as follows:
550 *
551 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
552 *
553 * - 'too large' values [that would result in larger than
554 * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
555 *
556 * - all other values are converted to jiffies by either multiplying
557 * the input value by a factor or dividing it with a factor and
558 * handling any 32-bit overflows.
559 * for the details see __msecs_to_jiffies()
560 *
561 * __msecs_to_jiffies() checks for the passed in value being a constant
562 * via __builtin_constant_p() allowing gcc to eliminate most of the
563 * code, __msecs_to_jiffies() is called if the value passed does not
564 * allow constant folding and the actual conversion must be done at
565 * runtime.
566 * The _msecs_to_jiffies helpers are the HZ dependent conversion
567 * routines found in include/linux/jiffies.h
568 *
569 * Return: jiffies value
570 */
571 unsigned long __msecs_to_jiffies(const unsigned int m)
572 {
573 /*
574 * Negative value, means infinite timeout:
575 */
576 if ((int)m < 0)
577 return MAX_JIFFY_OFFSET;
578 return _msecs_to_jiffies(m);
579 }
580 EXPORT_SYMBOL(__msecs_to_jiffies);
581
582 /**
583 * __usecs_to_jiffies: - convert microseconds to jiffies
584 * @u: time in milliseconds
585 *
586 * Return: jiffies value
587 */
588 unsigned long __usecs_to_jiffies(const unsigned int u)
589 {
590 if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
591 return MAX_JIFFY_OFFSET;
592 return _usecs_to_jiffies(u);
593 }
594 EXPORT_SYMBOL(__usecs_to_jiffies);
595
596 /**
597 * timespec64_to_jiffies - convert a timespec64 value to jiffies
598 * @value: pointer to &struct timespec64
599 *
600 * The TICK_NSEC - 1 rounds up the value to the next resolution. Note
601 * that a remainder subtract here would not do the right thing as the
602 * resolution values don't fall on second boundaries. I.e. the line:
603 * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
604 * Note that due to the small error in the multiplier here, this
605 * rounding is incorrect for sufficiently large values of tv_nsec, but
606 * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're
607 * OK.
608 *
609 * Rather, we just shift the bits off the right.
610 *
611 * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
612 * value to a scaled second value.
613 *
614 * Return: jiffies value
615 */
616 unsigned long
617 timespec64_to_jiffies(const struct timespec64 *value)
618 {
619 u64 sec = value->tv_sec;
620 long nsec = value->tv_nsec + TICK_NSEC - 1;
621
622 if (sec >= MAX_SEC_IN_JIFFIES){
623 sec = MAX_SEC_IN_JIFFIES;
624 nsec = 0;
625 }
626 return ((sec * SEC_CONVERSION) +
627 (((u64)nsec * NSEC_CONVERSION) >>
628 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
629
630 }
631 EXPORT_SYMBOL(timespec64_to_jiffies);
632
633 /**
634 * jiffies_to_timespec64 - convert jiffies value to &struct timespec64
635 * @jiffies: jiffies value
636 * @value: pointer to &struct timespec64
637 */
638 void
639 jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
640 {
641 /*
642 * Convert jiffies to nanoseconds and separate with
643 * one divide.
644 */
645 u32 rem;
646 value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
647 NSEC_PER_SEC, &rem);
648 value->tv_nsec = rem;
649 }
650 EXPORT_SYMBOL(jiffies_to_timespec64);
651
652 /*
653 * Convert jiffies/jiffies_64 to clock_t and back.
654 */
655
656 /**
657 * jiffies_to_clock_t - Convert jiffies to clock_t
658 * @x: jiffies value
659 *
660 * Return: jiffies converted to clock_t (CLOCKS_PER_SEC)
661 */
662 clock_t jiffies_to_clock_t(unsigned long x)
663 {
664 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
665 # if HZ < USER_HZ
666 return x * (USER_HZ / HZ);
667 # else
668 return x / (HZ / USER_HZ);
669 # endif
670 #else
671 return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
672 #endif
673 }
674 EXPORT_SYMBOL(jiffies_to_clock_t);
675
676 /**
677 * clock_t_to_jiffies - Convert clock_t to jiffies
678 * @x: clock_t value
679 *
680 * Return: clock_t value converted to jiffies
681 */
682 unsigned long clock_t_to_jiffies(unsigned long x)
683 {
684 #if (HZ % USER_HZ)==0
685 if (x >= ~0UL / (HZ / USER_HZ))
686 return ~0UL;
687 return x * (HZ / USER_HZ);
688 #else
689 /* Don't worry about loss of precision here .. */
690 if (x >= ~0UL / HZ * USER_HZ)
691 return ~0UL;
692
693 /* .. but do try to contain it here */
694 return div_u64((u64)x * HZ, USER_HZ);
695 #endif
696 }
697 EXPORT_SYMBOL(clock_t_to_jiffies);
698
699 /**
700 * jiffies_64_to_clock_t - Convert jiffies_64 to clock_t
701 * @x: jiffies_64 value
702 *
703 * Return: jiffies_64 value converted to 64-bit "clock_t" (CLOCKS_PER_SEC)
704 */
705 u64 jiffies_64_to_clock_t(u64 x)
706 {
707 #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
708 # if HZ < USER_HZ
709 x = div_u64(x * USER_HZ, HZ);
710 # elif HZ > USER_HZ
711 x = div_u64(x, HZ / USER_HZ);
712 # else
713 /* Nothing to do */
714 # endif
715 #else
716 /*
717 * There are better ways that don't overflow early,
718 * but even this doesn't overflow in hundreds of years
719 * in 64 bits, so..
720 */
721 x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
722 #endif
723 return x;
724 }
725 EXPORT_SYMBOL(jiffies_64_to_clock_t);
726
727 /**
728 * nsec_to_clock_t - Convert nsec value to clock_t
729 * @x: nsec value
730 *
731 * Return: nsec value converted to 64-bit "clock_t" (CLOCKS_PER_SEC)
732 */
733 u64 nsec_to_clock_t(u64 x)
734 {
735 #if (NSEC_PER_SEC % USER_HZ) == 0
736 return div_u64(x, NSEC_PER_SEC / USER_HZ);
737 #elif (USER_HZ % 512) == 0
738 return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
739 #else
740 /*
741 * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
742 * overflow after 64.99 years.
743 * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
744 */
745 return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
746 #endif
747 }
748
749 /**
750 * jiffies64_to_nsecs - Convert jiffies64 to nanoseconds
751 * @j: jiffies64 value
752 *
753 * Return: nanoseconds value
754 */
755 u64 jiffies64_to_nsecs(u64 j)
756 {
757 #if !(NSEC_PER_SEC % HZ)
758 return (NSEC_PER_SEC / HZ) * j;
759 # else
760 return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN);
761 #endif
762 }
763 EXPORT_SYMBOL(jiffies64_to_nsecs);
764
765 /**
766 * jiffies64_to_msecs - Convert jiffies64 to milliseconds
767 * @j: jiffies64 value
768 *
769 * Return: milliseconds value
770 */
771 u64 jiffies64_to_msecs(const u64 j)
772 {
773 #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
774 return (MSEC_PER_SEC / HZ) * j;
775 #else
776 return div_u64(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
777 #endif
778 }
779 EXPORT_SYMBOL(jiffies64_to_msecs);
780
781 /**
782 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
783 *
784 * @n: nsecs in u64
785 *
786 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
787 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
788 * for scheduler, not for use in device drivers to calculate timeout value.
789 *
790 * note:
791 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
792 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
793 *
794 * Return: nsecs converted to jiffies64 value
795 */
796 u64 nsecs_to_jiffies64(u64 n)
797 {
798 #if (NSEC_PER_SEC % HZ) == 0
799 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
800 return div_u64(n, NSEC_PER_SEC / HZ);
801 #elif (HZ % 512) == 0
802 /* overflow after 292 years if HZ = 1024 */
803 return div_u64(n * HZ / 512, NSEC_PER_SEC / 512);
804 #else
805 /*
806 * Generic case - optimized for cases where HZ is a multiple of 3.
807 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc.
808 */
809 return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ);
810 #endif
811 }
812 EXPORT_SYMBOL(nsecs_to_jiffies64);
813
814 /**
815 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
816 *
817 * @n: nsecs in u64
818 *
819 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
820 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
821 * for scheduler, not for use in device drivers to calculate timeout value.
822 *
823 * note:
824 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
825 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
826 *
827 * Return: nsecs converted to jiffies value
828 */
829 unsigned long nsecs_to_jiffies(u64 n)
830 {
831 return (unsigned long)nsecs_to_jiffies64(n);
832 }
833 EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
834
835 /**
836 * timespec64_add_safe - Add two timespec64 values and do a safety check
837 * for overflow.
838 * @lhs: first (left) timespec64 to add
839 * @rhs: second (right) timespec64 to add
840 *
841 * It's assumed that both values are valid (>= 0).
842 * And, each timespec64 is in normalized form.
843 *
844 * Return: sum of @lhs + @rhs
845 */
846 struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
847 const struct timespec64 rhs)
848 {
849 struct timespec64 res;
850
851 set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
852 lhs.tv_nsec + rhs.tv_nsec);
853
854 if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
855 res.tv_sec = TIME64_MAX;
856 res.tv_nsec = 0;
857 }
858
859 return res;
860 }
861
862 /**
863 * get_timespec64 - get user's time value into kernel space
864 * @ts: destination &struct timespec64
865 * @uts: user's time value as &struct __kernel_timespec
866 *
867 * Handles compat or 32-bit modes.
868 *
869 * Return: %0 on success or negative errno on error
870 */
871 int get_timespec64(struct timespec64 *ts,
872 const struct __kernel_timespec __user *uts)
873 {
874 struct __kernel_timespec kts;
875 int ret;
876
877 ret = copy_from_user(&kts, uts, sizeof(kts));
878 if (ret)
879 return -EFAULT;
880
881 ts->tv_sec = kts.tv_sec;
882
883 /* Zero out the padding in compat mode */
884 if (in_compat_syscall())
885 kts.tv_nsec &= 0xFFFFFFFFUL;
886
887 /* In 32-bit mode, this drops the padding */
888 ts->tv_nsec = kts.tv_nsec;
889
890 return 0;
891 }
892 EXPORT_SYMBOL_GPL(get_timespec64);
893
894 /**
895 * put_timespec64 - convert timespec64 value to __kernel_timespec format and
896 * copy the latter to userspace
897 * @ts: input &struct timespec64
898 * @uts: user's &struct __kernel_timespec
899 *
900 * Return: %0 on success or negative errno on error
901 */
902 int put_timespec64(const struct timespec64 *ts,
903 struct __kernel_timespec __user *uts)
904 {
905 struct __kernel_timespec kts = {
906 .tv_sec = ts->tv_sec,
907 .tv_nsec = ts->tv_nsec
908 };
909
910 return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0;
911 }
912 EXPORT_SYMBOL_GPL(put_timespec64);
913
914 static int __get_old_timespec32(struct timespec64 *ts64,
915 const struct old_timespec32 __user *cts)
916 {
917 struct old_timespec32 ts;
918 int ret;
919
920 ret = copy_from_user(&ts, cts, sizeof(ts));
921 if (ret)
922 return -EFAULT;
923
924 ts64->tv_sec = ts.tv_sec;
925 ts64->tv_nsec = ts.tv_nsec;
926
927 return 0;
928 }
929
930 static int __put_old_timespec32(const struct timespec64 *ts64,
931 struct old_timespec32 __user *cts)
932 {
933 struct old_timespec32 ts = {
934 .tv_sec = ts64->tv_sec,
935 .tv_nsec = ts64->tv_nsec
936 };
937 return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0;
938 }
939
940 /**
941 * get_old_timespec32 - get user's old-format time value into kernel space
942 * @ts: destination &struct timespec64
943 * @uts: user's old-format time value (&struct old_timespec32)
944 *
945 * Handles X86_X32_ABI compatibility conversion.
946 *
947 * Return: %0 on success or negative errno on error
948 */
949 int get_old_timespec32(struct timespec64 *ts, const void __user *uts)
950 {
951 if (COMPAT_USE_64BIT_TIME)
952 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
953 else
954 return __get_old_timespec32(ts, uts);
955 }
956 EXPORT_SYMBOL_GPL(get_old_timespec32);
957
958 /**
959 * put_old_timespec32 - convert timespec64 value to &struct old_timespec32 and
960 * copy the latter to userspace
961 * @ts: input &struct timespec64
962 * @uts: user's &struct old_timespec32
963 *
964 * Handles X86_X32_ABI compatibility conversion.
965 *
966 * Return: %0 on success or negative errno on error
967 */
968 int put_old_timespec32(const struct timespec64 *ts, void __user *uts)
969 {
970 if (COMPAT_USE_64BIT_TIME)
971 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
972 else
973 return __put_old_timespec32(ts, uts);
974 }
975 EXPORT_SYMBOL_GPL(put_old_timespec32);
976
977 /**
978 * get_itimerspec64 - get user's &struct __kernel_itimerspec into kernel space
979 * @it: destination &struct itimerspec64
980 * @uit: user's &struct __kernel_itimerspec
981 *
982 * Return: %0 on success or negative errno on error
983 */
984 int get_itimerspec64(struct itimerspec64 *it,
985 const struct __kernel_itimerspec __user *uit)
986 {
987 int ret;
988
989 ret = get_timespec64(&it->it_interval, &uit->it_interval);
990 if (ret)
991 return ret;
992
993 ret = get_timespec64(&it->it_value, &uit->it_value);
994
995 return ret;
996 }
997 EXPORT_SYMBOL_GPL(get_itimerspec64);
998
999 /**
1000 * put_itimerspec64 - convert &struct itimerspec64 to __kernel_itimerspec format
1001 * and copy the latter to userspace
1002 * @it: input &struct itimerspec64
1003 * @uit: user's &struct __kernel_itimerspec
1004 *
1005 * Return: %0 on success or negative errno on error
1006 */
1007 int put_itimerspec64(const struct itimerspec64 *it,
1008 struct __kernel_itimerspec __user *uit)
1009 {
1010 int ret;
1011
1012 ret = put_timespec64(&it->it_interval, &uit->it_interval);
1013 if (ret)
1014 return ret;
1015
1016 ret = put_timespec64(&it->it_value, &uit->it_value);
1017
1018 return ret;
1019 }
1020 EXPORT_SYMBOL_GPL(put_itimerspec64);
1021
1022 /**
1023 * get_old_itimerspec32 - get user's &struct old_itimerspec32 into kernel space
1024 * @its: destination &struct itimerspec64
1025 * @uits: user's &struct old_itimerspec32
1026 *
1027 * Return: %0 on success or negative errno on error
1028 */
1029 int get_old_itimerspec32(struct itimerspec64 *its,
1030 const struct old_itimerspec32 __user *uits)
1031 {
1032
1033 if (__get_old_timespec32(&its->it_interval, &uits->it_interval) ||
1034 __get_old_timespec32(&its->it_value, &uits->it_value))
1035 return -EFAULT;
1036 return 0;
1037 }
1038 EXPORT_SYMBOL_GPL(get_old_itimerspec32);
1039
1040 /**
1041 * put_old_itimerspec32 - convert &struct itimerspec64 to &struct
1042 * old_itimerspec32 and copy the latter to userspace
1043 * @its: input &struct itimerspec64
1044 * @uits: user's &struct old_itimerspec32
1045 *
1046 * Return: %0 on success or negative errno on error
1047 */
1048 int put_old_itimerspec32(const struct itimerspec64 *its,
1049 struct old_itimerspec32 __user *uits)
1050 {
1051 if (__put_old_timespec32(&its->it_interval, &uits->it_interval) ||
1052 __put_old_timespec32(&its->it_value, &uits->it_value))
1053 return -EFAULT;
1054 return 0;
1055 }
1056 EXPORT_SYMBOL_GPL(put_old_itimerspec32);
1057
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