Commit | Line | Data |
---|---|---|
1da177e4 LT |
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.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/module.h> | |
31 | #include <linux/timex.h> | |
c59ede7b | 32 | #include <linux/capability.h> |
1da177e4 LT |
33 | #include <linux/errno.h> |
34 | #include <linux/smp_lock.h> | |
35 | #include <linux/syscalls.h> | |
36 | #include <linux/security.h> | |
37 | #include <linux/fs.h> | |
38 | #include <linux/module.h> | |
39 | ||
40 | #include <asm/uaccess.h> | |
41 | #include <asm/unistd.h> | |
42 | ||
43 | /* | |
44 | * The timezone where the local system is located. Used as a default by some | |
45 | * programs who obtain this value by using gettimeofday. | |
46 | */ | |
47 | struct timezone sys_tz; | |
48 | ||
49 | EXPORT_SYMBOL(sys_tz); | |
50 | ||
51 | #ifdef __ARCH_WANT_SYS_TIME | |
52 | ||
53 | /* | |
54 | * sys_time() can be implemented in user-level using | |
55 | * sys_gettimeofday(). Is this for backwards compatibility? If so, | |
56 | * why not move it into the appropriate arch directory (for those | |
57 | * architectures that need it). | |
58 | */ | |
59 | asmlinkage long sys_time(time_t __user * tloc) | |
60 | { | |
61 | time_t i; | |
62 | struct timeval tv; | |
63 | ||
64 | do_gettimeofday(&tv); | |
65 | i = tv.tv_sec; | |
66 | ||
67 | if (tloc) { | |
68 | if (put_user(i,tloc)) | |
69 | i = -EFAULT; | |
70 | } | |
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 | asmlinkage long sys_stime(time_t __user *tptr) | |
82 | { | |
83 | struct timespec 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_settime(&tv, NULL); | |
92 | if (err) | |
93 | return err; | |
94 | ||
95 | do_settimeofday(&tv); | |
96 | return 0; | |
97 | } | |
98 | ||
99 | #endif /* __ARCH_WANT_SYS_TIME */ | |
100 | ||
101 | asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __user *tz) | |
102 | { | |
103 | if (likely(tv != NULL)) { | |
104 | struct timeval ktv; | |
105 | do_gettimeofday(&ktv); | |
106 | if (copy_to_user(tv, &ktv, sizeof(ktv))) | |
107 | return -EFAULT; | |
108 | } | |
109 | if (unlikely(tz != NULL)) { | |
110 | if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) | |
111 | return -EFAULT; | |
112 | } | |
113 | return 0; | |
114 | } | |
115 | ||
116 | /* | |
117 | * Adjust the time obtained from the CMOS to be UTC time instead of | |
118 | * local time. | |
119 | * | |
120 | * This is ugly, but preferable to the alternatives. Otherwise we | |
121 | * would either need to write a program to do it in /etc/rc (and risk | |
122 | * confusion if the program gets run more than once; it would also be | |
123 | * hard to make the program warp the clock precisely n hours) or | |
124 | * compile in the timezone information into the kernel. Bad, bad.... | |
125 | * | |
126 | * - TYT, 1992-01-01 | |
127 | * | |
128 | * The best thing to do is to keep the CMOS clock in universal time (UTC) | |
129 | * as real UNIX machines always do it. This avoids all headaches about | |
130 | * daylight saving times and warping kernel clocks. | |
131 | */ | |
77933d72 | 132 | static inline void warp_clock(void) |
1da177e4 LT |
133 | { |
134 | write_seqlock_irq(&xtime_lock); | |
135 | wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60; | |
136 | xtime.tv_sec += sys_tz.tz_minuteswest * 60; | |
137 | time_interpolator_reset(); | |
138 | write_sequnlock_irq(&xtime_lock); | |
139 | clock_was_set(); | |
140 | } | |
141 | ||
142 | /* | |
143 | * In case for some reason the CMOS clock has not already been running | |
144 | * in UTC, but in some local time: The first time we set the timezone, | |
145 | * we will warp the clock so that it is ticking UTC time instead of | |
146 | * local time. Presumably, if someone is setting the timezone then we | |
147 | * are running in an environment where the programs understand about | |
148 | * timezones. This should be done at boot time in the /etc/rc script, | |
149 | * as soon as possible, so that the clock can be set right. Otherwise, | |
150 | * various programs will get confused when the clock gets warped. | |
151 | */ | |
152 | ||
153 | int do_sys_settimeofday(struct timespec *tv, struct timezone *tz) | |
154 | { | |
155 | static int firsttime = 1; | |
156 | int error = 0; | |
157 | ||
951069e3 | 158 | if (tv && !timespec_valid(tv)) |
718bcceb TG |
159 | return -EINVAL; |
160 | ||
1da177e4 LT |
161 | error = security_settime(tv, tz); |
162 | if (error) | |
163 | return error; | |
164 | ||
165 | if (tz) { | |
166 | /* SMP safe, global irq locking makes it work. */ | |
167 | sys_tz = *tz; | |
168 | if (firsttime) { | |
169 | firsttime = 0; | |
170 | if (!tv) | |
171 | warp_clock(); | |
172 | } | |
173 | } | |
174 | if (tv) | |
175 | { | |
176 | /* SMP safe, again the code in arch/foo/time.c should | |
177 | * globally block out interrupts when it runs. | |
178 | */ | |
179 | return do_settimeofday(tv); | |
180 | } | |
181 | return 0; | |
182 | } | |
183 | ||
184 | asmlinkage long sys_settimeofday(struct timeval __user *tv, | |
185 | struct timezone __user *tz) | |
186 | { | |
187 | struct timeval user_tv; | |
188 | struct timespec new_ts; | |
189 | struct timezone new_tz; | |
190 | ||
191 | if (tv) { | |
192 | if (copy_from_user(&user_tv, tv, sizeof(*tv))) | |
193 | return -EFAULT; | |
194 | new_ts.tv_sec = user_tv.tv_sec; | |
195 | new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; | |
196 | } | |
197 | if (tz) { | |
198 | if (copy_from_user(&new_tz, tz, sizeof(*tz))) | |
199 | return -EFAULT; | |
200 | } | |
201 | ||
202 | return do_sys_settimeofday(tv ? &new_ts : NULL, tz ? &new_tz : NULL); | |
203 | } | |
204 | ||
1da177e4 LT |
205 | asmlinkage long sys_adjtimex(struct timex __user *txc_p) |
206 | { | |
207 | struct timex txc; /* Local copy of parameter */ | |
208 | int ret; | |
209 | ||
210 | /* Copy the user data space into the kernel copy | |
211 | * structure. But bear in mind that the structures | |
212 | * may change | |
213 | */ | |
214 | if(copy_from_user(&txc, txc_p, sizeof(struct timex))) | |
215 | return -EFAULT; | |
216 | ret = do_adjtimex(&txc); | |
217 | return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret; | |
218 | } | |
219 | ||
220 | inline struct timespec current_kernel_time(void) | |
221 | { | |
222 | struct timespec now; | |
223 | unsigned long seq; | |
224 | ||
225 | do { | |
226 | seq = read_seqbegin(&xtime_lock); | |
227 | ||
228 | now = xtime; | |
229 | } while (read_seqretry(&xtime_lock, seq)); | |
230 | ||
231 | return now; | |
232 | } | |
233 | ||
234 | EXPORT_SYMBOL(current_kernel_time); | |
235 | ||
236 | /** | |
237 | * current_fs_time - Return FS time | |
238 | * @sb: Superblock. | |
239 | * | |
8ba8e95e | 240 | * Return the current time truncated to the time granularity supported by |
1da177e4 LT |
241 | * the fs. |
242 | */ | |
243 | struct timespec current_fs_time(struct super_block *sb) | |
244 | { | |
245 | struct timespec now = current_kernel_time(); | |
246 | return timespec_trunc(now, sb->s_time_gran); | |
247 | } | |
248 | EXPORT_SYMBOL(current_fs_time); | |
249 | ||
250 | /** | |
8ba8e95e | 251 | * timespec_trunc - Truncate timespec to a granularity |
1da177e4 | 252 | * @t: Timespec |
8ba8e95e | 253 | * @gran: Granularity in ns. |
1da177e4 | 254 | * |
8ba8e95e | 255 | * Truncate a timespec to a granularity. gran must be smaller than a second. |
1da177e4 LT |
256 | * Always rounds down. |
257 | * | |
258 | * This function should be only used for timestamps returned by | |
259 | * current_kernel_time() or CURRENT_TIME, not with do_gettimeofday() because | |
260 | * it doesn't handle the better resolution of the later. | |
261 | */ | |
262 | struct timespec timespec_trunc(struct timespec t, unsigned gran) | |
263 | { | |
264 | /* | |
265 | * Division is pretty slow so avoid it for common cases. | |
266 | * Currently current_kernel_time() never returns better than | |
267 | * jiffies resolution. Exploit that. | |
268 | */ | |
269 | if (gran <= jiffies_to_usecs(1) * 1000) { | |
270 | /* nothing */ | |
271 | } else if (gran == 1000000000) { | |
272 | t.tv_nsec = 0; | |
273 | } else { | |
274 | t.tv_nsec -= t.tv_nsec % gran; | |
275 | } | |
276 | return t; | |
277 | } | |
278 | EXPORT_SYMBOL(timespec_trunc); | |
279 | ||
280 | #ifdef CONFIG_TIME_INTERPOLATION | |
281 | void getnstimeofday (struct timespec *tv) | |
282 | { | |
283 | unsigned long seq,sec,nsec; | |
284 | ||
285 | do { | |
286 | seq = read_seqbegin(&xtime_lock); | |
287 | sec = xtime.tv_sec; | |
288 | nsec = xtime.tv_nsec+time_interpolator_get_offset(); | |
289 | } while (unlikely(read_seqretry(&xtime_lock, seq))); | |
290 | ||
291 | while (unlikely(nsec >= NSEC_PER_SEC)) { | |
292 | nsec -= NSEC_PER_SEC; | |
293 | ++sec; | |
294 | } | |
295 | tv->tv_sec = sec; | |
296 | tv->tv_nsec = nsec; | |
297 | } | |
298 | EXPORT_SYMBOL_GPL(getnstimeofday); | |
299 | ||
300 | int do_settimeofday (struct timespec *tv) | |
301 | { | |
302 | time_t wtm_sec, sec = tv->tv_sec; | |
303 | long wtm_nsec, nsec = tv->tv_nsec; | |
304 | ||
305 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
306 | return -EINVAL; | |
307 | ||
308 | write_seqlock_irq(&xtime_lock); | |
309 | { | |
1da177e4 LT |
310 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); |
311 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); | |
312 | ||
313 | set_normalized_timespec(&xtime, sec, nsec); | |
314 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
315 | ||
316 | time_adjust = 0; /* stop active adjtime() */ | |
317 | time_status |= STA_UNSYNC; | |
318 | time_maxerror = NTP_PHASE_LIMIT; | |
319 | time_esterror = NTP_PHASE_LIMIT; | |
320 | time_interpolator_reset(); | |
321 | } | |
322 | write_sequnlock_irq(&xtime_lock); | |
323 | clock_was_set(); | |
324 | return 0; | |
325 | } | |
943eae03 | 326 | EXPORT_SYMBOL(do_settimeofday); |
1da177e4 LT |
327 | |
328 | void do_gettimeofday (struct timeval *tv) | |
329 | { | |
330 | unsigned long seq, nsec, usec, sec, offset; | |
331 | do { | |
332 | seq = read_seqbegin(&xtime_lock); | |
333 | offset = time_interpolator_get_offset(); | |
334 | sec = xtime.tv_sec; | |
335 | nsec = xtime.tv_nsec; | |
336 | } while (unlikely(read_seqretry(&xtime_lock, seq))); | |
337 | ||
338 | usec = (nsec + offset) / 1000; | |
339 | ||
340 | while (unlikely(usec >= USEC_PER_SEC)) { | |
341 | usec -= USEC_PER_SEC; | |
342 | ++sec; | |
343 | } | |
344 | ||
345 | tv->tv_sec = sec; | |
346 | tv->tv_usec = usec; | |
347 | } | |
348 | ||
349 | EXPORT_SYMBOL(do_gettimeofday); | |
350 | ||
351 | ||
352 | #else | |
cf3c769b | 353 | #ifndef CONFIG_GENERIC_TIME |
1da177e4 LT |
354 | /* |
355 | * Simulate gettimeofday using do_gettimeofday which only allows a timeval | |
356 | * and therefore only yields usec accuracy | |
357 | */ | |
358 | void getnstimeofday(struct timespec *tv) | |
359 | { | |
360 | struct timeval x; | |
361 | ||
362 | do_gettimeofday(&x); | |
363 | tv->tv_sec = x.tv_sec; | |
364 | tv->tv_nsec = x.tv_usec * NSEC_PER_USEC; | |
365 | } | |
c6ecf7ed | 366 | EXPORT_SYMBOL_GPL(getnstimeofday); |
1da177e4 | 367 | #endif |
cf3c769b | 368 | #endif |
1da177e4 | 369 | |
753be622 TG |
370 | /* Converts Gregorian date to seconds since 1970-01-01 00:00:00. |
371 | * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 | |
372 | * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. | |
373 | * | |
374 | * [For the Julian calendar (which was used in Russia before 1917, | |
375 | * Britain & colonies before 1752, anywhere else before 1582, | |
376 | * and is still in use by some communities) leave out the | |
377 | * -year/100+year/400 terms, and add 10.] | |
378 | * | |
379 | * This algorithm was first published by Gauss (I think). | |
380 | * | |
381 | * WARNING: this function will overflow on 2106-02-07 06:28:16 on | |
382 | * machines were long is 32-bit! (However, as time_t is signed, we | |
383 | * will already get problems at other places on 2038-01-19 03:14:08) | |
384 | */ | |
385 | unsigned long | |
f4818900 IM |
386 | mktime(const unsigned int year0, const unsigned int mon0, |
387 | const unsigned int day, const unsigned int hour, | |
388 | const unsigned int min, const unsigned int sec) | |
753be622 | 389 | { |
f4818900 IM |
390 | unsigned int mon = mon0, year = year0; |
391 | ||
392 | /* 1..12 -> 11,12,1..10 */ | |
393 | if (0 >= (int) (mon -= 2)) { | |
394 | mon += 12; /* Puts Feb last since it has leap day */ | |
753be622 TG |
395 | year -= 1; |
396 | } | |
397 | ||
398 | return ((((unsigned long) | |
399 | (year/4 - year/100 + year/400 + 367*mon/12 + day) + | |
400 | year*365 - 719499 | |
401 | )*24 + hour /* now have hours */ | |
402 | )*60 + min /* now have minutes */ | |
403 | )*60 + sec; /* finally seconds */ | |
404 | } | |
405 | ||
199e7056 AM |
406 | EXPORT_SYMBOL(mktime); |
407 | ||
753be622 TG |
408 | /** |
409 | * set_normalized_timespec - set timespec sec and nsec parts and normalize | |
410 | * | |
411 | * @ts: pointer to timespec variable to be set | |
412 | * @sec: seconds to set | |
413 | * @nsec: nanoseconds to set | |
414 | * | |
415 | * Set seconds and nanoseconds field of a timespec variable and | |
416 | * normalize to the timespec storage format | |
417 | * | |
418 | * Note: The tv_nsec part is always in the range of | |
419 | * 0 <= tv_nsec < NSEC_PER_SEC | |
420 | * For negative values only the tv_sec field is negative ! | |
421 | */ | |
f4818900 | 422 | void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec) |
753be622 TG |
423 | { |
424 | while (nsec >= NSEC_PER_SEC) { | |
425 | nsec -= NSEC_PER_SEC; | |
426 | ++sec; | |
427 | } | |
428 | while (nsec < 0) { | |
429 | nsec += NSEC_PER_SEC; | |
430 | --sec; | |
431 | } | |
432 | ts->tv_sec = sec; | |
433 | ts->tv_nsec = nsec; | |
434 | } | |
435 | ||
f8f46da3 TG |
436 | /** |
437 | * ns_to_timespec - Convert nanoseconds to timespec | |
438 | * @nsec: the nanoseconds value to be converted | |
439 | * | |
440 | * Returns the timespec representation of the nsec parameter. | |
441 | */ | |
df869b63 | 442 | struct timespec ns_to_timespec(const s64 nsec) |
f8f46da3 TG |
443 | { |
444 | struct timespec ts; | |
445 | ||
88fc3897 GA |
446 | if (!nsec) |
447 | return (struct timespec) {0, 0}; | |
448 | ||
449 | ts.tv_sec = div_long_long_rem_signed(nsec, NSEC_PER_SEC, &ts.tv_nsec); | |
450 | if (unlikely(nsec < 0)) | |
451 | set_normalized_timespec(&ts, ts.tv_sec, ts.tv_nsec); | |
f8f46da3 TG |
452 | |
453 | return ts; | |
454 | } | |
455 | ||
456 | /** | |
457 | * ns_to_timeval - Convert nanoseconds to timeval | |
458 | * @nsec: the nanoseconds value to be converted | |
459 | * | |
460 | * Returns the timeval representation of the nsec parameter. | |
461 | */ | |
df869b63 | 462 | struct timeval ns_to_timeval(const s64 nsec) |
f8f46da3 TG |
463 | { |
464 | struct timespec ts = ns_to_timespec(nsec); | |
465 | struct timeval tv; | |
466 | ||
467 | tv.tv_sec = ts.tv_sec; | |
468 | tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000; | |
469 | ||
470 | return tv; | |
471 | } | |
472 | ||
8b9365d7 IM |
473 | /* |
474 | * Convert jiffies to milliseconds and back. | |
475 | * | |
476 | * Avoid unnecessary multiplications/divisions in the | |
477 | * two most common HZ cases: | |
478 | */ | |
479 | unsigned int jiffies_to_msecs(const unsigned long j) | |
480 | { | |
481 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) | |
482 | return (MSEC_PER_SEC / HZ) * j; | |
483 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) | |
484 | return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); | |
485 | #else | |
486 | return (j * MSEC_PER_SEC) / HZ; | |
487 | #endif | |
488 | } | |
489 | EXPORT_SYMBOL(jiffies_to_msecs); | |
490 | ||
491 | unsigned int jiffies_to_usecs(const unsigned long j) | |
492 | { | |
493 | #if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ) | |
494 | return (USEC_PER_SEC / HZ) * j; | |
495 | #elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) | |
496 | return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC); | |
497 | #else | |
498 | return (j * USEC_PER_SEC) / HZ; | |
499 | #endif | |
500 | } | |
501 | EXPORT_SYMBOL(jiffies_to_usecs); | |
502 | ||
503 | unsigned long msecs_to_jiffies(const unsigned int m) | |
504 | { | |
505 | if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) | |
506 | return MAX_JIFFY_OFFSET; | |
507 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) | |
508 | return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ); | |
509 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) | |
510 | return m * (HZ / MSEC_PER_SEC); | |
511 | #else | |
512 | return (m * HZ + MSEC_PER_SEC - 1) / MSEC_PER_SEC; | |
513 | #endif | |
514 | } | |
515 | EXPORT_SYMBOL(msecs_to_jiffies); | |
516 | ||
517 | unsigned long usecs_to_jiffies(const unsigned int u) | |
518 | { | |
519 | if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) | |
520 | return MAX_JIFFY_OFFSET; | |
521 | #if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ) | |
522 | return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ); | |
523 | #elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) | |
524 | return u * (HZ / USEC_PER_SEC); | |
525 | #else | |
526 | return (u * HZ + USEC_PER_SEC - 1) / USEC_PER_SEC; | |
527 | #endif | |
528 | } | |
529 | EXPORT_SYMBOL(usecs_to_jiffies); | |
530 | ||
531 | /* | |
532 | * The TICK_NSEC - 1 rounds up the value to the next resolution. Note | |
533 | * that a remainder subtract here would not do the right thing as the | |
534 | * resolution values don't fall on second boundries. I.e. the line: | |
535 | * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding. | |
536 | * | |
537 | * Rather, we just shift the bits off the right. | |
538 | * | |
539 | * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec | |
540 | * value to a scaled second value. | |
541 | */ | |
542 | unsigned long | |
543 | timespec_to_jiffies(const struct timespec *value) | |
544 | { | |
545 | unsigned long sec = value->tv_sec; | |
546 | long nsec = value->tv_nsec + TICK_NSEC - 1; | |
547 | ||
548 | if (sec >= MAX_SEC_IN_JIFFIES){ | |
549 | sec = MAX_SEC_IN_JIFFIES; | |
550 | nsec = 0; | |
551 | } | |
552 | return (((u64)sec * SEC_CONVERSION) + | |
553 | (((u64)nsec * NSEC_CONVERSION) >> | |
554 | (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; | |
555 | ||
556 | } | |
557 | EXPORT_SYMBOL(timespec_to_jiffies); | |
558 | ||
559 | void | |
560 | jiffies_to_timespec(const unsigned long jiffies, struct timespec *value) | |
561 | { | |
562 | /* | |
563 | * Convert jiffies to nanoseconds and separate with | |
564 | * one divide. | |
565 | */ | |
566 | u64 nsec = (u64)jiffies * TICK_NSEC; | |
567 | value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &value->tv_nsec); | |
568 | } | |
569 | EXPORT_SYMBOL(jiffies_to_timespec); | |
570 | ||
571 | /* Same for "timeval" | |
572 | * | |
573 | * Well, almost. The problem here is that the real system resolution is | |
574 | * in nanoseconds and the value being converted is in micro seconds. | |
575 | * Also for some machines (those that use HZ = 1024, in-particular), | |
576 | * there is a LARGE error in the tick size in microseconds. | |
577 | ||
578 | * The solution we use is to do the rounding AFTER we convert the | |
579 | * microsecond part. Thus the USEC_ROUND, the bits to be shifted off. | |
580 | * Instruction wise, this should cost only an additional add with carry | |
581 | * instruction above the way it was done above. | |
582 | */ | |
583 | unsigned long | |
584 | timeval_to_jiffies(const struct timeval *value) | |
585 | { | |
586 | unsigned long sec = value->tv_sec; | |
587 | long usec = value->tv_usec; | |
588 | ||
589 | if (sec >= MAX_SEC_IN_JIFFIES){ | |
590 | sec = MAX_SEC_IN_JIFFIES; | |
591 | usec = 0; | |
592 | } | |
593 | return (((u64)sec * SEC_CONVERSION) + | |
594 | (((u64)usec * USEC_CONVERSION + USEC_ROUND) >> | |
595 | (USEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; | |
596 | } | |
597 | ||
598 | void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value) | |
599 | { | |
600 | /* | |
601 | * Convert jiffies to nanoseconds and separate with | |
602 | * one divide. | |
603 | */ | |
604 | u64 nsec = (u64)jiffies * TICK_NSEC; | |
605 | long tv_usec; | |
606 | ||
607 | value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &tv_usec); | |
608 | tv_usec /= NSEC_PER_USEC; | |
609 | value->tv_usec = tv_usec; | |
610 | } | |
611 | ||
612 | /* | |
613 | * Convert jiffies/jiffies_64 to clock_t and back. | |
614 | */ | |
615 | clock_t jiffies_to_clock_t(long x) | |
616 | { | |
617 | #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 | |
618 | return x / (HZ / USER_HZ); | |
619 | #else | |
620 | u64 tmp = (u64)x * TICK_NSEC; | |
621 | do_div(tmp, (NSEC_PER_SEC / USER_HZ)); | |
622 | return (long)tmp; | |
623 | #endif | |
624 | } | |
625 | EXPORT_SYMBOL(jiffies_to_clock_t); | |
626 | ||
627 | unsigned long clock_t_to_jiffies(unsigned long x) | |
628 | { | |
629 | #if (HZ % USER_HZ)==0 | |
630 | if (x >= ~0UL / (HZ / USER_HZ)) | |
631 | return ~0UL; | |
632 | return x * (HZ / USER_HZ); | |
633 | #else | |
634 | u64 jif; | |
635 | ||
636 | /* Don't worry about loss of precision here .. */ | |
637 | if (x >= ~0UL / HZ * USER_HZ) | |
638 | return ~0UL; | |
639 | ||
640 | /* .. but do try to contain it here */ | |
641 | jif = x * (u64) HZ; | |
642 | do_div(jif, USER_HZ); | |
643 | return jif; | |
644 | #endif | |
645 | } | |
646 | EXPORT_SYMBOL(clock_t_to_jiffies); | |
647 | ||
648 | u64 jiffies_64_to_clock_t(u64 x) | |
649 | { | |
650 | #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 | |
651 | do_div(x, HZ / USER_HZ); | |
652 | #else | |
653 | /* | |
654 | * There are better ways that don't overflow early, | |
655 | * but even this doesn't overflow in hundreds of years | |
656 | * in 64 bits, so.. | |
657 | */ | |
658 | x *= TICK_NSEC; | |
659 | do_div(x, (NSEC_PER_SEC / USER_HZ)); | |
660 | #endif | |
661 | return x; | |
662 | } | |
663 | ||
664 | EXPORT_SYMBOL(jiffies_64_to_clock_t); | |
665 | ||
666 | u64 nsec_to_clock_t(u64 x) | |
667 | { | |
668 | #if (NSEC_PER_SEC % USER_HZ) == 0 | |
669 | do_div(x, (NSEC_PER_SEC / USER_HZ)); | |
670 | #elif (USER_HZ % 512) == 0 | |
671 | x *= USER_HZ/512; | |
672 | do_div(x, (NSEC_PER_SEC / 512)); | |
673 | #else | |
674 | /* | |
675 | * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, | |
676 | * overflow after 64.99 years. | |
677 | * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... | |
678 | */ | |
679 | x *= 9; | |
680 | do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (USER_HZ/2)) / | |
681 | USER_HZ)); | |
682 | #endif | |
683 | return x; | |
684 | } | |
685 | ||
1da177e4 LT |
686 | #if (BITS_PER_LONG < 64) |
687 | u64 get_jiffies_64(void) | |
688 | { | |
689 | unsigned long seq; | |
690 | u64 ret; | |
691 | ||
692 | do { | |
693 | seq = read_seqbegin(&xtime_lock); | |
694 | ret = jiffies_64; | |
695 | } while (read_seqretry(&xtime_lock, seq)); | |
696 | return ret; | |
697 | } | |
698 | ||
699 | EXPORT_SYMBOL(get_jiffies_64); | |
700 | #endif | |
701 | ||
702 | EXPORT_SYMBOL(jiffies); |