![Matt Helsley](/assets/img/avatar_default.png)
There are several functions that might seem appropriate for a timestamp: get_cycles() current_kernel_time() do_gettimeofday() <read jiffies/jiffies_64> Each has problems with combinations of SMP-safety, low resolution, and monotonicity. This patch adds a new function that returns a monotonic SMP-safe timestamp with nanosecond resolution where available. Changes: Split timestamp into separate patch Moved to kernel/time.c Renamed to getnstimestamp Fixed unintended-pointer-arithmetic bug Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
175 lines
4.6 KiB
C
175 lines
4.6 KiB
C
#ifndef _LINUX_TIME_H
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#define _LINUX_TIME_H
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#include <linux/types.h>
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#ifdef __KERNEL__
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#include <linux/seqlock.h>
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#endif
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#ifndef _STRUCT_TIMESPEC
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#define _STRUCT_TIMESPEC
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struct timespec {
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time_t tv_sec; /* seconds */
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long tv_nsec; /* nanoseconds */
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};
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#endif /* _STRUCT_TIMESPEC */
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struct timeval {
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time_t tv_sec; /* seconds */
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suseconds_t tv_usec; /* microseconds */
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};
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struct timezone {
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int tz_minuteswest; /* minutes west of Greenwich */
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int tz_dsttime; /* type of dst correction */
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};
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#ifdef __KERNEL__
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/* Parameters used to convert the timespec values */
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#define MSEC_PER_SEC (1000L)
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#define USEC_PER_SEC (1000000L)
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#define NSEC_PER_SEC (1000000000L)
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#define NSEC_PER_USEC (1000L)
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static __inline__ int timespec_equal(struct timespec *a, struct timespec *b)
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{
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return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
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}
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/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
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* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
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* => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
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*
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* [For the Julian calendar (which was used in Russia before 1917,
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* Britain & colonies before 1752, anywhere else before 1582,
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* and is still in use by some communities) leave out the
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* -year/100+year/400 terms, and add 10.]
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*
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* This algorithm was first published by Gauss (I think).
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*
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* WARNING: this function will overflow on 2106-02-07 06:28:16 on
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* machines were long is 32-bit! (However, as time_t is signed, we
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* will already get problems at other places on 2038-01-19 03:14:08)
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*/
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static inline unsigned long
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mktime (unsigned int year, unsigned int mon,
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unsigned int day, unsigned int hour,
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unsigned int min, unsigned int sec)
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{
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if (0 >= (int) (mon -= 2)) { /* 1..12 -> 11,12,1..10 */
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mon += 12; /* Puts Feb last since it has leap day */
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year -= 1;
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}
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return (((
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(unsigned long) (year/4 - year/100 + year/400 + 367*mon/12 + day) +
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year*365 - 719499
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)*24 + hour /* now have hours */
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)*60 + min /* now have minutes */
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)*60 + sec; /* finally seconds */
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}
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extern struct timespec xtime;
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extern struct timespec wall_to_monotonic;
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extern seqlock_t xtime_lock;
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static inline unsigned long get_seconds(void)
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{
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return xtime.tv_sec;
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}
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struct timespec current_kernel_time(void);
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#define CURRENT_TIME (current_kernel_time())
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#define CURRENT_TIME_SEC ((struct timespec) { xtime.tv_sec, 0 })
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extern void do_gettimeofday(struct timeval *tv);
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extern int do_settimeofday(struct timespec *tv);
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extern int do_sys_settimeofday(struct timespec *tv, struct timezone *tz);
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extern void clock_was_set(void); // call when ever the clock is set
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extern int do_posix_clock_monotonic_gettime(struct timespec *tp);
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extern long do_utimes(char __user * filename, struct timeval * times);
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struct itimerval;
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extern int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue);
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extern int do_getitimer(int which, struct itimerval *value);
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extern void getnstimeofday (struct timespec *tv);
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extern void getnstimestamp(struct timespec *ts);
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extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
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static inline void
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set_normalized_timespec (struct timespec *ts, time_t sec, long nsec)
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{
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while (nsec >= NSEC_PER_SEC) {
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nsec -= NSEC_PER_SEC;
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++sec;
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}
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while (nsec < 0) {
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nsec += NSEC_PER_SEC;
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--sec;
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}
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ts->tv_sec = sec;
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ts->tv_nsec = nsec;
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}
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#endif /* __KERNEL__ */
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#define NFDBITS __NFDBITS
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#define FD_SETSIZE __FD_SETSIZE
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#define FD_SET(fd,fdsetp) __FD_SET(fd,fdsetp)
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#define FD_CLR(fd,fdsetp) __FD_CLR(fd,fdsetp)
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#define FD_ISSET(fd,fdsetp) __FD_ISSET(fd,fdsetp)
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#define FD_ZERO(fdsetp) __FD_ZERO(fdsetp)
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/*
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* Names of the interval timers, and structure
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* defining a timer setting.
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*/
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#define ITIMER_REAL 0
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#define ITIMER_VIRTUAL 1
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#define ITIMER_PROF 2
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struct itimerspec {
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struct timespec it_interval; /* timer period */
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struct timespec it_value; /* timer expiration */
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};
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struct itimerval {
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struct timeval it_interval; /* timer interval */
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struct timeval it_value; /* current value */
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};
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/*
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* The IDs of the various system clocks (for POSIX.1b interval timers).
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*/
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#define CLOCK_REALTIME 0
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#define CLOCK_MONOTONIC 1
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#define CLOCK_PROCESS_CPUTIME_ID 2
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#define CLOCK_THREAD_CPUTIME_ID 3
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#define CLOCK_REALTIME_HR 4
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#define CLOCK_MONOTONIC_HR 5
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/*
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* The IDs of various hardware clocks
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*/
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#define CLOCK_SGI_CYCLE 10
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#define MAX_CLOCKS 16
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#define CLOCKS_MASK (CLOCK_REALTIME | CLOCK_MONOTONIC | \
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CLOCK_REALTIME_HR | CLOCK_MONOTONIC_HR)
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#define CLOCKS_MONO (CLOCK_MONOTONIC & CLOCK_MONOTONIC_HR)
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/*
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* The various flags for setting POSIX.1b interval timers.
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*/
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#define TIMER_ABSTIME 0x01
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#endif
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