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 | |
6fa6c3b1 | 12 | * |
1da177e4 | 13 | * 1993-09-02 Philip Gladstone |
0a0fca9d | 14 | * Created file with time related functions from sched/core.c and adjtimex() |
1da177e4 LT |
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 | ||
9984de1a | 30 | #include <linux/export.h> |
1da177e4 | 31 | #include <linux/timex.h> |
c59ede7b | 32 | #include <linux/capability.h> |
189374ae | 33 | #include <linux/timekeeper_internal.h> |
1da177e4 | 34 | #include <linux/errno.h> |
1da177e4 LT |
35 | #include <linux/syscalls.h> |
36 | #include <linux/security.h> | |
37 | #include <linux/fs.h> | |
71abb3af | 38 | #include <linux/math64.h> |
e3d5a27d | 39 | #include <linux/ptrace.h> |
1da177e4 | 40 | |
7c0f6ba6 | 41 | #include <linux/uaccess.h> |
3a4d44b6 | 42 | #include <linux/compat.h> |
1da177e4 LT |
43 | #include <asm/unistd.h> |
44 | ||
0a227985 | 45 | #include <generated/timeconst.h> |
8b094cd0 | 46 | #include "timekeeping.h" |
bdc80787 | 47 | |
6fa6c3b1 | 48 | /* |
1da177e4 LT |
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 | */ | |
52 | struct timezone sys_tz; | |
53 | ||
54 | EXPORT_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 | */ | |
58fd3aa2 | 64 | SYSCALL_DEFINE1(time, time_t __user *, tloc) |
1da177e4 | 65 | { |
f20bf612 | 66 | time_t i = get_seconds(); |
1da177e4 LT |
67 | |
68 | if (tloc) { | |
20082208 | 69 | if (put_user(i,tloc)) |
e3d5a27d | 70 | return -EFAULT; |
1da177e4 | 71 | } |
e3d5a27d | 72 | force_successful_syscall_return(); |
1da177e4 LT |
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 | */ | |
6fa6c3b1 | 82 | |
58fd3aa2 | 83 | SYSCALL_DEFINE1(stime, time_t __user *, tptr) |
1da177e4 LT |
84 | { |
85 | struct timespec 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_settime(&tv, NULL); | |
94 | if (err) | |
95 | return err; | |
96 | ||
97 | do_settimeofday(&tv); | |
98 | return 0; | |
99 | } | |
100 | ||
101 | #endif /* __ARCH_WANT_SYS_TIME */ | |
102 | ||
b180db2c AV |
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. */ | |
107 | COMPAT_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 | ||
123 | COMPAT_SYSCALL_DEFINE1(stime, compat_time_t __user *, tptr) | |
124 | { | |
125 | struct timespec 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_settime(&tv, NULL); | |
134 | if (err) | |
135 | return err; | |
136 | ||
137 | do_settimeofday(&tv); | |
138 | return 0; | |
139 | } | |
140 | ||
141 | #endif /* __ARCH_WANT_COMPAT_SYS_TIME */ | |
142 | #endif | |
143 | ||
58fd3aa2 HC |
144 | SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv, |
145 | struct timezone __user *, tz) | |
1da177e4 LT |
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 | ||
84e345e4 PB |
160 | /* |
161 | * Indicates if there is an offset between the system clock and the hardware | |
162 | * clock/persistent clock/rtc. | |
163 | */ | |
164 | int persistent_clock_is_local; | |
165 | ||
1da177e4 LT |
166 | /* |
167 | * Adjust the time obtained from the CMOS to be UTC time instead of | |
168 | * local time. | |
6fa6c3b1 | 169 | * |
1da177e4 LT |
170 | * This is ugly, but preferable to the alternatives. Otherwise we |
171 | * would either need to write a program to do it in /etc/rc (and risk | |
6fa6c3b1 | 172 | * confusion if the program gets run more than once; it would also be |
1da177e4 LT |
173 | * hard to make the program warp the clock precisely n hours) or |
174 | * compile in the timezone information into the kernel. Bad, bad.... | |
175 | * | |
bdc80787 | 176 | * - TYT, 1992-01-01 |
1da177e4 LT |
177 | * |
178 | * The best thing to do is to keep the CMOS clock in universal time (UTC) | |
179 | * as real UNIX machines always do it. This avoids all headaches about | |
180 | * daylight saving times and warping kernel clocks. | |
181 | */ | |
77933d72 | 182 | static inline void warp_clock(void) |
1da177e4 | 183 | { |
c30bd099 DZ |
184 | if (sys_tz.tz_minuteswest != 0) { |
185 | struct timespec adjust; | |
bd45b7a3 | 186 | |
84e345e4 | 187 | persistent_clock_is_local = 1; |
7859e404 JS |
188 | adjust.tv_sec = sys_tz.tz_minuteswest * 60; |
189 | adjust.tv_nsec = 0; | |
190 | timekeeping_inject_offset(&adjust); | |
c30bd099 | 191 | } |
1da177e4 LT |
192 | } |
193 | ||
194 | /* | |
195 | * In case for some reason the CMOS clock has not already been running | |
196 | * in UTC, but in some local time: The first time we set the timezone, | |
197 | * we will warp the clock so that it is ticking UTC time instead of | |
198 | * local time. Presumably, if someone is setting the timezone then we | |
199 | * are running in an environment where the programs understand about | |
200 | * timezones. This should be done at boot time in the /etc/rc script, | |
201 | * as soon as possible, so that the clock can be set right. Otherwise, | |
202 | * various programs will get confused when the clock gets warped. | |
203 | */ | |
204 | ||
86d34732 | 205 | int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz) |
1da177e4 LT |
206 | { |
207 | static int firsttime = 1; | |
208 | int error = 0; | |
209 | ||
86d34732 | 210 | if (tv && !timespec64_valid(tv)) |
718bcceb TG |
211 | return -EINVAL; |
212 | ||
86d34732 | 213 | error = security_settime64(tv, tz); |
1da177e4 LT |
214 | if (error) |
215 | return error; | |
216 | ||
217 | if (tz) { | |
6f7d7984 SL |
218 | /* Verify we're witin the +-15 hrs range */ |
219 | if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60) | |
220 | return -EINVAL; | |
221 | ||
1da177e4 | 222 | sys_tz = *tz; |
2c622148 | 223 | update_vsyscall_tz(); |
1da177e4 LT |
224 | if (firsttime) { |
225 | firsttime = 0; | |
226 | if (!tv) | |
227 | warp_clock(); | |
228 | } | |
229 | } | |
230 | if (tv) | |
86d34732 | 231 | return do_settimeofday64(tv); |
1da177e4 LT |
232 | return 0; |
233 | } | |
234 | ||
58fd3aa2 HC |
235 | SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, |
236 | struct timezone __user *, tz) | |
1da177e4 | 237 | { |
2ac00f17 | 238 | struct timespec64 new_ts; |
1da177e4 | 239 | struct timeval user_tv; |
1da177e4 LT |
240 | struct timezone new_tz; |
241 | ||
242 | if (tv) { | |
243 | if (copy_from_user(&user_tv, tv, sizeof(*tv))) | |
244 | return -EFAULT; | |
6ada1fc0 SL |
245 | |
246 | if (!timeval_valid(&user_tv)) | |
247 | return -EINVAL; | |
248 | ||
1da177e4 LT |
249 | new_ts.tv_sec = user_tv.tv_sec; |
250 | new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; | |
251 | } | |
252 | if (tz) { | |
253 | if (copy_from_user(&new_tz, tz, sizeof(*tz))) | |
254 | return -EFAULT; | |
255 | } | |
256 | ||
2ac00f17 | 257 | return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL); |
1da177e4 LT |
258 | } |
259 | ||
2b2d0285 AV |
260 | #ifdef CONFIG_COMPAT |
261 | COMPAT_SYSCALL_DEFINE2(gettimeofday, struct compat_timeval __user *, tv, | |
262 | struct timezone __user *, tz) | |
263 | { | |
264 | if (tv) { | |
265 | struct timeval ktv; | |
266 | ||
267 | do_gettimeofday(&ktv); | |
268 | if (compat_put_timeval(&ktv, tv)) | |
269 | return -EFAULT; | |
270 | } | |
271 | if (tz) { | |
272 | if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) | |
273 | return -EFAULT; | |
274 | } | |
275 | ||
276 | return 0; | |
277 | } | |
278 | ||
279 | COMPAT_SYSCALL_DEFINE2(settimeofday, struct compat_timeval __user *, tv, | |
280 | struct timezone __user *, tz) | |
281 | { | |
282 | struct timespec64 new_ts; | |
283 | struct timeval user_tv; | |
284 | struct timezone new_tz; | |
285 | ||
286 | if (tv) { | |
287 | if (compat_get_timeval(&user_tv, tv)) | |
288 | return -EFAULT; | |
289 | new_ts.tv_sec = user_tv.tv_sec; | |
290 | new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; | |
291 | } | |
292 | if (tz) { | |
293 | if (copy_from_user(&new_tz, tz, sizeof(*tz))) | |
294 | return -EFAULT; | |
295 | } | |
296 | ||
297 | return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL); | |
298 | } | |
299 | #endif | |
300 | ||
58fd3aa2 | 301 | SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p) |
1da177e4 LT |
302 | { |
303 | struct timex txc; /* Local copy of parameter */ | |
304 | int ret; | |
305 | ||
306 | /* Copy the user data space into the kernel copy | |
307 | * structure. But bear in mind that the structures | |
308 | * may change | |
309 | */ | |
3a4d44b6 | 310 | if (copy_from_user(&txc, txc_p, sizeof(struct timex))) |
1da177e4 LT |
311 | return -EFAULT; |
312 | ret = do_adjtimex(&txc); | |
313 | return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret; | |
314 | } | |
315 | ||
3a4d44b6 AV |
316 | #ifdef CONFIG_COMPAT |
317 | ||
318 | COMPAT_SYSCALL_DEFINE1(adjtimex, struct compat_timex __user *, utp) | |
319 | { | |
320 | struct timex txc; | |
321 | int err, ret; | |
322 | ||
323 | err = compat_get_timex(&txc, utp); | |
324 | if (err) | |
325 | return err; | |
326 | ||
327 | ret = do_adjtimex(&txc); | |
328 | ||
329 | err = compat_put_timex(utp, &txc); | |
330 | if (err) | |
331 | return err; | |
332 | ||
333 | return ret; | |
334 | } | |
335 | #endif | |
336 | ||
753e9c5c ED |
337 | /* |
338 | * Convert jiffies to milliseconds and back. | |
339 | * | |
340 | * Avoid unnecessary multiplications/divisions in the | |
341 | * two most common HZ cases: | |
342 | */ | |
af3b5628 | 343 | unsigned int jiffies_to_msecs(const unsigned long j) |
753e9c5c ED |
344 | { |
345 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) | |
346 | return (MSEC_PER_SEC / HZ) * j; | |
347 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) | |
348 | return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); | |
349 | #else | |
bdc80787 | 350 | # if BITS_PER_LONG == 32 |
b9095fd8 | 351 | return (HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32; |
bdc80787 PA |
352 | # else |
353 | return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN; | |
354 | # endif | |
753e9c5c ED |
355 | #endif |
356 | } | |
357 | EXPORT_SYMBOL(jiffies_to_msecs); | |
358 | ||
af3b5628 | 359 | unsigned int jiffies_to_usecs(const unsigned long j) |
753e9c5c | 360 | { |
e0758676 FW |
361 | /* |
362 | * Hz usually doesn't go much further MSEC_PER_SEC. | |
363 | * jiffies_to_usecs() and usecs_to_jiffies() depend on that. | |
364 | */ | |
365 | BUILD_BUG_ON(HZ > USEC_PER_SEC); | |
366 | ||
367 | #if !(USEC_PER_SEC % HZ) | |
753e9c5c | 368 | return (USEC_PER_SEC / HZ) * j; |
753e9c5c | 369 | #else |
bdc80787 | 370 | # if BITS_PER_LONG == 32 |
b9095fd8 | 371 | return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32; |
bdc80787 PA |
372 | # else |
373 | return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN; | |
374 | # endif | |
753e9c5c ED |
375 | #endif |
376 | } | |
377 | EXPORT_SYMBOL(jiffies_to_usecs); | |
378 | ||
1da177e4 | 379 | /** |
8ba8e95e | 380 | * timespec_trunc - Truncate timespec to a granularity |
1da177e4 | 381 | * @t: Timespec |
8ba8e95e | 382 | * @gran: Granularity in ns. |
1da177e4 | 383 | * |
de4a95fa KB |
384 | * Truncate a timespec to a granularity. Always rounds down. gran must |
385 | * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns). | |
1da177e4 LT |
386 | */ |
387 | struct timespec timespec_trunc(struct timespec t, unsigned gran) | |
388 | { | |
de4a95fa KB |
389 | /* Avoid division in the common cases 1 ns and 1 s. */ |
390 | if (gran == 1) { | |
1da177e4 | 391 | /* nothing */ |
de4a95fa | 392 | } else if (gran == NSEC_PER_SEC) { |
1da177e4 | 393 | t.tv_nsec = 0; |
de4a95fa | 394 | } else if (gran > 1 && gran < NSEC_PER_SEC) { |
1da177e4 | 395 | t.tv_nsec -= t.tv_nsec % gran; |
de4a95fa KB |
396 | } else { |
397 | WARN(1, "illegal file time granularity: %u", gran); | |
1da177e4 LT |
398 | } |
399 | return t; | |
400 | } | |
401 | EXPORT_SYMBOL(timespec_trunc); | |
402 | ||
90b6ce9c | 403 | /* |
404 | * mktime64 - Converts date to seconds. | |
405 | * Converts Gregorian date to seconds since 1970-01-01 00:00:00. | |
753be622 TG |
406 | * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 |
407 | * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. | |
408 | * | |
409 | * [For the Julian calendar (which was used in Russia before 1917, | |
410 | * Britain & colonies before 1752, anywhere else before 1582, | |
411 | * and is still in use by some communities) leave out the | |
412 | * -year/100+year/400 terms, and add 10.] | |
413 | * | |
414 | * This algorithm was first published by Gauss (I think). | |
ede5147d DH |
415 | * |
416 | * A leap second can be indicated by calling this function with sec as | |
417 | * 60 (allowable under ISO 8601). The leap second is treated the same | |
418 | * as the following second since they don't exist in UNIX time. | |
419 | * | |
420 | * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight | |
421 | * tomorrow - (allowable under ISO 8601) is supported. | |
753be622 | 422 | */ |
90b6ce9c | 423 | time64_t mktime64(const unsigned int year0, const unsigned int mon0, |
424 | const unsigned int day, const unsigned int hour, | |
425 | const unsigned int min, const unsigned int sec) | |
753be622 | 426 | { |
f4818900 IM |
427 | unsigned int mon = mon0, year = year0; |
428 | ||
429 | /* 1..12 -> 11,12,1..10 */ | |
430 | if (0 >= (int) (mon -= 2)) { | |
431 | mon += 12; /* Puts Feb last since it has leap day */ | |
753be622 TG |
432 | year -= 1; |
433 | } | |
434 | ||
90b6ce9c | 435 | return ((((time64_t) |
753be622 TG |
436 | (year/4 - year/100 + year/400 + 367*mon/12 + day) + |
437 | year*365 - 719499 | |
ede5147d | 438 | )*24 + hour /* now have hours - midnight tomorrow handled here */ |
753be622 TG |
439 | )*60 + min /* now have minutes */ |
440 | )*60 + sec; /* finally seconds */ | |
441 | } | |
90b6ce9c | 442 | EXPORT_SYMBOL(mktime64); |
199e7056 | 443 | |
753be622 TG |
444 | /** |
445 | * set_normalized_timespec - set timespec sec and nsec parts and normalize | |
446 | * | |
447 | * @ts: pointer to timespec variable to be set | |
448 | * @sec: seconds to set | |
449 | * @nsec: nanoseconds to set | |
450 | * | |
451 | * Set seconds and nanoseconds field of a timespec variable and | |
452 | * normalize to the timespec storage format | |
453 | * | |
454 | * Note: The tv_nsec part is always in the range of | |
bdc80787 | 455 | * 0 <= tv_nsec < NSEC_PER_SEC |
753be622 TG |
456 | * For negative values only the tv_sec field is negative ! |
457 | */ | |
12e09337 | 458 | void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec) |
753be622 TG |
459 | { |
460 | while (nsec >= NSEC_PER_SEC) { | |
12e09337 TG |
461 | /* |
462 | * The following asm() prevents the compiler from | |
463 | * optimising this loop into a modulo operation. See | |
464 | * also __iter_div_u64_rem() in include/linux/time.h | |
465 | */ | |
466 | asm("" : "+rm"(nsec)); | |
753be622 TG |
467 | nsec -= NSEC_PER_SEC; |
468 | ++sec; | |
469 | } | |
470 | while (nsec < 0) { | |
12e09337 | 471 | asm("" : "+rm"(nsec)); |
753be622 TG |
472 | nsec += NSEC_PER_SEC; |
473 | --sec; | |
474 | } | |
475 | ts->tv_sec = sec; | |
476 | ts->tv_nsec = nsec; | |
477 | } | |
7c3f944e | 478 | EXPORT_SYMBOL(set_normalized_timespec); |
753be622 | 479 | |
f8f46da3 TG |
480 | /** |
481 | * ns_to_timespec - Convert nanoseconds to timespec | |
482 | * @nsec: the nanoseconds value to be converted | |
483 | * | |
484 | * Returns the timespec representation of the nsec parameter. | |
485 | */ | |
df869b63 | 486 | struct timespec ns_to_timespec(const s64 nsec) |
f8f46da3 TG |
487 | { |
488 | struct timespec ts; | |
f8bd2258 | 489 | s32 rem; |
f8f46da3 | 490 | |
88fc3897 GA |
491 | if (!nsec) |
492 | return (struct timespec) {0, 0}; | |
493 | ||
f8bd2258 RZ |
494 | ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem); |
495 | if (unlikely(rem < 0)) { | |
496 | ts.tv_sec--; | |
497 | rem += NSEC_PER_SEC; | |
498 | } | |
499 | ts.tv_nsec = rem; | |
f8f46da3 TG |
500 | |
501 | return ts; | |
502 | } | |
85795d64 | 503 | EXPORT_SYMBOL(ns_to_timespec); |
f8f46da3 TG |
504 | |
505 | /** | |
506 | * ns_to_timeval - Convert nanoseconds to timeval | |
507 | * @nsec: the nanoseconds value to be converted | |
508 | * | |
509 | * Returns the timeval representation of the nsec parameter. | |
510 | */ | |
df869b63 | 511 | struct timeval ns_to_timeval(const s64 nsec) |
f8f46da3 TG |
512 | { |
513 | struct timespec ts = ns_to_timespec(nsec); | |
514 | struct timeval tv; | |
515 | ||
516 | tv.tv_sec = ts.tv_sec; | |
517 | tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000; | |
518 | ||
519 | return tv; | |
520 | } | |
b7aa0bf7 | 521 | EXPORT_SYMBOL(ns_to_timeval); |
f8f46da3 | 522 | |
49cd6f86 JS |
523 | #if BITS_PER_LONG == 32 |
524 | /** | |
525 | * set_normalized_timespec - set timespec sec and nsec parts and normalize | |
526 | * | |
527 | * @ts: pointer to timespec variable to be set | |
528 | * @sec: seconds to set | |
529 | * @nsec: nanoseconds to set | |
530 | * | |
531 | * Set seconds and nanoseconds field of a timespec variable and | |
532 | * normalize to the timespec storage format | |
533 | * | |
534 | * Note: The tv_nsec part is always in the range of | |
535 | * 0 <= tv_nsec < NSEC_PER_SEC | |
536 | * For negative values only the tv_sec field is negative ! | |
537 | */ | |
538 | void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec) | |
539 | { | |
540 | while (nsec >= NSEC_PER_SEC) { | |
541 | /* | |
542 | * The following asm() prevents the compiler from | |
543 | * optimising this loop into a modulo operation. See | |
544 | * also __iter_div_u64_rem() in include/linux/time.h | |
545 | */ | |
546 | asm("" : "+rm"(nsec)); | |
547 | nsec -= NSEC_PER_SEC; | |
548 | ++sec; | |
549 | } | |
550 | while (nsec < 0) { | |
551 | asm("" : "+rm"(nsec)); | |
552 | nsec += NSEC_PER_SEC; | |
553 | --sec; | |
554 | } | |
555 | ts->tv_sec = sec; | |
556 | ts->tv_nsec = nsec; | |
557 | } | |
558 | EXPORT_SYMBOL(set_normalized_timespec64); | |
559 | ||
560 | /** | |
561 | * ns_to_timespec64 - Convert nanoseconds to timespec64 | |
562 | * @nsec: the nanoseconds value to be converted | |
563 | * | |
564 | * Returns the timespec64 representation of the nsec parameter. | |
565 | */ | |
566 | struct timespec64 ns_to_timespec64(const s64 nsec) | |
567 | { | |
568 | struct timespec64 ts; | |
569 | s32 rem; | |
570 | ||
571 | if (!nsec) | |
572 | return (struct timespec64) {0, 0}; | |
573 | ||
574 | ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem); | |
575 | if (unlikely(rem < 0)) { | |
576 | ts.tv_sec--; | |
577 | rem += NSEC_PER_SEC; | |
578 | } | |
579 | ts.tv_nsec = rem; | |
580 | ||
581 | return ts; | |
582 | } | |
583 | EXPORT_SYMBOL(ns_to_timespec64); | |
584 | #endif | |
ca42aaf0 NMG |
585 | /** |
586 | * msecs_to_jiffies: - convert milliseconds to jiffies | |
587 | * @m: time in milliseconds | |
588 | * | |
589 | * conversion is done as follows: | |
41cf5445 IM |
590 | * |
591 | * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) | |
592 | * | |
593 | * - 'too large' values [that would result in larger than | |
594 | * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. | |
595 | * | |
596 | * - all other values are converted to jiffies by either multiplying | |
ca42aaf0 NMG |
597 | * the input value by a factor or dividing it with a factor and |
598 | * handling any 32-bit overflows. | |
599 | * for the details see __msecs_to_jiffies() | |
41cf5445 | 600 | * |
ca42aaf0 NMG |
601 | * msecs_to_jiffies() checks for the passed in value being a constant |
602 | * via __builtin_constant_p() allowing gcc to eliminate most of the | |
603 | * code, __msecs_to_jiffies() is called if the value passed does not | |
604 | * allow constant folding and the actual conversion must be done at | |
605 | * runtime. | |
606 | * the _msecs_to_jiffies helpers are the HZ dependent conversion | |
607 | * routines found in include/linux/jiffies.h | |
41cf5445 | 608 | */ |
ca42aaf0 | 609 | unsigned long __msecs_to_jiffies(const unsigned int m) |
8b9365d7 | 610 | { |
41cf5445 IM |
611 | /* |
612 | * Negative value, means infinite timeout: | |
613 | */ | |
614 | if ((int)m < 0) | |
8b9365d7 | 615 | return MAX_JIFFY_OFFSET; |
ca42aaf0 | 616 | return _msecs_to_jiffies(m); |
8b9365d7 | 617 | } |
ca42aaf0 | 618 | EXPORT_SYMBOL(__msecs_to_jiffies); |
8b9365d7 | 619 | |
ae60d6a0 | 620 | unsigned long __usecs_to_jiffies(const unsigned int u) |
8b9365d7 IM |
621 | { |
622 | if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) | |
623 | return MAX_JIFFY_OFFSET; | |
ae60d6a0 | 624 | return _usecs_to_jiffies(u); |
8b9365d7 | 625 | } |
ae60d6a0 | 626 | EXPORT_SYMBOL(__usecs_to_jiffies); |
8b9365d7 IM |
627 | |
628 | /* | |
629 | * The TICK_NSEC - 1 rounds up the value to the next resolution. Note | |
630 | * that a remainder subtract here would not do the right thing as the | |
631 | * resolution values don't fall on second boundries. I.e. the line: | |
632 | * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding. | |
d78c9300 AH |
633 | * Note that due to the small error in the multiplier here, this |
634 | * rounding is incorrect for sufficiently large values of tv_nsec, but | |
635 | * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're | |
636 | * OK. | |
8b9365d7 IM |
637 | * |
638 | * Rather, we just shift the bits off the right. | |
639 | * | |
640 | * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec | |
641 | * value to a scaled second value. | |
642 | */ | |
d78c9300 | 643 | static unsigned long |
9ca30850 | 644 | __timespec64_to_jiffies(u64 sec, long nsec) |
8b9365d7 | 645 | { |
d78c9300 | 646 | nsec = nsec + TICK_NSEC - 1; |
8b9365d7 IM |
647 | |
648 | if (sec >= MAX_SEC_IN_JIFFIES){ | |
649 | sec = MAX_SEC_IN_JIFFIES; | |
650 | nsec = 0; | |
651 | } | |
9ca30850 | 652 | return ((sec * SEC_CONVERSION) + |
8b9365d7 IM |
653 | (((u64)nsec * NSEC_CONVERSION) >> |
654 | (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; | |
655 | ||
656 | } | |
d78c9300 | 657 | |
9ca30850 BW |
658 | static unsigned long |
659 | __timespec_to_jiffies(unsigned long sec, long nsec) | |
d78c9300 | 660 | { |
9ca30850 | 661 | return __timespec64_to_jiffies((u64)sec, nsec); |
d78c9300 AH |
662 | } |
663 | ||
9ca30850 BW |
664 | unsigned long |
665 | timespec64_to_jiffies(const struct timespec64 *value) | |
666 | { | |
667 | return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec); | |
668 | } | |
669 | EXPORT_SYMBOL(timespec64_to_jiffies); | |
8b9365d7 IM |
670 | |
671 | void | |
9ca30850 | 672 | jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value) |
8b9365d7 IM |
673 | { |
674 | /* | |
675 | * Convert jiffies to nanoseconds and separate with | |
676 | * one divide. | |
677 | */ | |
f8bd2258 RZ |
678 | u32 rem; |
679 | value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, | |
680 | NSEC_PER_SEC, &rem); | |
681 | value->tv_nsec = rem; | |
8b9365d7 | 682 | } |
9ca30850 | 683 | EXPORT_SYMBOL(jiffies_to_timespec64); |
8b9365d7 | 684 | |
d78c9300 AH |
685 | /* |
686 | * We could use a similar algorithm to timespec_to_jiffies (with a | |
687 | * different multiplier for usec instead of nsec). But this has a | |
688 | * problem with rounding: we can't exactly add TICK_NSEC - 1 to the | |
689 | * usec value, since it's not necessarily integral. | |
690 | * | |
691 | * We could instead round in the intermediate scaled representation | |
692 | * (i.e. in units of 1/2^(large scale) jiffies) but that's also | |
693 | * perilous: the scaling introduces a small positive error, which | |
694 | * combined with a division-rounding-upward (i.e. adding 2^(scale) - 1 | |
695 | * units to the intermediate before shifting) leads to accidental | |
696 | * overflow and overestimates. | |
8b9365d7 | 697 | * |
d78c9300 AH |
698 | * At the cost of one additional multiplication by a constant, just |
699 | * use the timespec implementation. | |
8b9365d7 IM |
700 | */ |
701 | unsigned long | |
702 | timeval_to_jiffies(const struct timeval *value) | |
703 | { | |
d78c9300 AH |
704 | return __timespec_to_jiffies(value->tv_sec, |
705 | value->tv_usec * NSEC_PER_USEC); | |
8b9365d7 | 706 | } |
456a09dc | 707 | EXPORT_SYMBOL(timeval_to_jiffies); |
8b9365d7 IM |
708 | |
709 | void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value) | |
710 | { | |
711 | /* | |
712 | * Convert jiffies to nanoseconds and separate with | |
713 | * one divide. | |
714 | */ | |
f8bd2258 | 715 | u32 rem; |
8b9365d7 | 716 | |
f8bd2258 RZ |
717 | value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC, |
718 | NSEC_PER_SEC, &rem); | |
719 | value->tv_usec = rem / NSEC_PER_USEC; | |
8b9365d7 | 720 | } |
456a09dc | 721 | EXPORT_SYMBOL(jiffies_to_timeval); |
8b9365d7 IM |
722 | |
723 | /* | |
724 | * Convert jiffies/jiffies_64 to clock_t and back. | |
725 | */ | |
cbbc719f | 726 | clock_t jiffies_to_clock_t(unsigned long x) |
8b9365d7 IM |
727 | { |
728 | #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 | |
6ffc787a DF |
729 | # if HZ < USER_HZ |
730 | return x * (USER_HZ / HZ); | |
731 | # else | |
8b9365d7 | 732 | return x / (HZ / USER_HZ); |
6ffc787a | 733 | # endif |
8b9365d7 | 734 | #else |
71abb3af | 735 | return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); |
8b9365d7 IM |
736 | #endif |
737 | } | |
738 | EXPORT_SYMBOL(jiffies_to_clock_t); | |
739 | ||
740 | unsigned long clock_t_to_jiffies(unsigned long x) | |
741 | { | |
742 | #if (HZ % USER_HZ)==0 | |
743 | if (x >= ~0UL / (HZ / USER_HZ)) | |
744 | return ~0UL; | |
745 | return x * (HZ / USER_HZ); | |
746 | #else | |
8b9365d7 IM |
747 | /* Don't worry about loss of precision here .. */ |
748 | if (x >= ~0UL / HZ * USER_HZ) | |
749 | return ~0UL; | |
750 | ||
751 | /* .. but do try to contain it here */ | |
71abb3af | 752 | return div_u64((u64)x * HZ, USER_HZ); |
8b9365d7 IM |
753 | #endif |
754 | } | |
755 | EXPORT_SYMBOL(clock_t_to_jiffies); | |
756 | ||
757 | u64 jiffies_64_to_clock_t(u64 x) | |
758 | { | |
759 | #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 | |
6ffc787a | 760 | # if HZ < USER_HZ |
71abb3af | 761 | x = div_u64(x * USER_HZ, HZ); |
ec03d707 | 762 | # elif HZ > USER_HZ |
71abb3af | 763 | x = div_u64(x, HZ / USER_HZ); |
ec03d707 AM |
764 | # else |
765 | /* Nothing to do */ | |
6ffc787a | 766 | # endif |
8b9365d7 IM |
767 | #else |
768 | /* | |
769 | * There are better ways that don't overflow early, | |
770 | * but even this doesn't overflow in hundreds of years | |
771 | * in 64 bits, so.. | |
772 | */ | |
71abb3af | 773 | x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ)); |
8b9365d7 IM |
774 | #endif |
775 | return x; | |
776 | } | |
8b9365d7 IM |
777 | EXPORT_SYMBOL(jiffies_64_to_clock_t); |
778 | ||
779 | u64 nsec_to_clock_t(u64 x) | |
780 | { | |
781 | #if (NSEC_PER_SEC % USER_HZ) == 0 | |
71abb3af | 782 | return div_u64(x, NSEC_PER_SEC / USER_HZ); |
8b9365d7 | 783 | #elif (USER_HZ % 512) == 0 |
71abb3af | 784 | return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512); |
8b9365d7 IM |
785 | #else |
786 | /* | |
787 | * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, | |
788 | * overflow after 64.99 years. | |
789 | * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... | |
790 | */ | |
71abb3af | 791 | return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ); |
8b9365d7 | 792 | #endif |
8b9365d7 IM |
793 | } |
794 | ||
07e5f5e3 FW |
795 | u64 jiffies64_to_nsecs(u64 j) |
796 | { | |
797 | #if !(NSEC_PER_SEC % HZ) | |
798 | return (NSEC_PER_SEC / HZ) * j; | |
799 | # else | |
800 | return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN); | |
801 | #endif | |
802 | } | |
803 | EXPORT_SYMBOL(jiffies64_to_nsecs); | |
804 | ||
b7b20df9 | 805 | /** |
a1dabb6b | 806 | * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64 |
b7b20df9 HS |
807 | * |
808 | * @n: nsecs in u64 | |
809 | * | |
810 | * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. | |
811 | * And this doesn't return MAX_JIFFY_OFFSET since this function is designed | |
812 | * for scheduler, not for use in device drivers to calculate timeout value. | |
813 | * | |
814 | * note: | |
815 | * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) | |
816 | * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years | |
817 | */ | |
a1dabb6b | 818 | u64 nsecs_to_jiffies64(u64 n) |
b7b20df9 HS |
819 | { |
820 | #if (NSEC_PER_SEC % HZ) == 0 | |
821 | /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */ | |
822 | return div_u64(n, NSEC_PER_SEC / HZ); | |
823 | #elif (HZ % 512) == 0 | |
824 | /* overflow after 292 years if HZ = 1024 */ | |
825 | return div_u64(n * HZ / 512, NSEC_PER_SEC / 512); | |
826 | #else | |
827 | /* | |
828 | * Generic case - optimized for cases where HZ is a multiple of 3. | |
829 | * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc. | |
830 | */ | |
831 | return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ); | |
832 | #endif | |
833 | } | |
7bd0e226 | 834 | EXPORT_SYMBOL(nsecs_to_jiffies64); |
b7b20df9 | 835 | |
a1dabb6b VP |
836 | /** |
837 | * nsecs_to_jiffies - Convert nsecs in u64 to jiffies | |
838 | * | |
839 | * @n: nsecs in u64 | |
840 | * | |
841 | * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. | |
842 | * And this doesn't return MAX_JIFFY_OFFSET since this function is designed | |
843 | * for scheduler, not for use in device drivers to calculate timeout value. | |
844 | * | |
845 | * note: | |
846 | * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) | |
847 | * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years | |
848 | */ | |
849 | unsigned long nsecs_to_jiffies(u64 n) | |
850 | { | |
851 | return (unsigned long)nsecs_to_jiffies64(n); | |
852 | } | |
d560fed6 | 853 | EXPORT_SYMBOL_GPL(nsecs_to_jiffies); |
a1dabb6b | 854 | |
df0cc053 TG |
855 | /* |
856 | * Add two timespec values and do a safety check for overflow. | |
857 | * It's assumed that both values are valid (>= 0) | |
858 | */ | |
859 | struct timespec timespec_add_safe(const struct timespec lhs, | |
860 | const struct timespec rhs) | |
861 | { | |
862 | struct timespec res; | |
863 | ||
864 | set_normalized_timespec(&res, lhs.tv_sec + rhs.tv_sec, | |
865 | lhs.tv_nsec + rhs.tv_nsec); | |
866 | ||
867 | if (res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec) | |
868 | res.tv_sec = TIME_T_MAX; | |
869 | ||
870 | return res; | |
871 | } | |
bc2c53e5 | 872 | |
bc2c53e5 DD |
873 | /* |
874 | * Add two timespec64 values and do a safety check for overflow. | |
875 | * It's assumed that both values are valid (>= 0). | |
876 | * And, each timespec64 is in normalized form. | |
877 | */ | |
878 | struct timespec64 timespec64_add_safe(const struct timespec64 lhs, | |
879 | const struct timespec64 rhs) | |
880 | { | |
881 | struct timespec64 res; | |
882 | ||
469e857f | 883 | set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec, |
bc2c53e5 DD |
884 | lhs.tv_nsec + rhs.tv_nsec); |
885 | ||
886 | if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) { | |
887 | res.tv_sec = TIME64_MAX; | |
888 | res.tv_nsec = 0; | |
889 | } | |
890 | ||
891 | return res; | |
892 | } |