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- /*
- * include/linux/ktime.h
- *
- * ktime_t - nanosecond-resolution time format.
- *
- * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
- * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
- *
- * data type definitions, declarations, prototypes and macros.
- *
- * Started by: Thomas Gleixner and Ingo Molnar
- *
- * Credits:
- *
- * Roman Zippel provided the ideas and primary code snippets of
- * the ktime_t union and further simplifications of the original
- * code.
- *
- * For licencing details see kernel-base/COPYING
- */
- #ifndef _LINUX_KTIME_H
- #define _LINUX_KTIME_H
- #include <linux/time.h>
- #include <linux/jiffies.h>
- /*
- * ktime_t:
- *
- * On 64-bit CPUs a single 64-bit variable is used to store the hrtimers
- * internal representation of time values in scalar nanoseconds. The
- * design plays out best on 64-bit CPUs, where most conversions are
- * NOPs and most arithmetic ktime_t operations are plain arithmetic
- * operations.
- *
- * On 32-bit CPUs an optimized representation of the timespec structure
- * is used to avoid expensive conversions from and to timespecs. The
- * endian-aware order of the tv struct members is choosen to allow
- * mathematical operations on the tv64 member of the union too, which
- * for certain operations produces better code.
- *
- * For architectures with efficient support for 64/32-bit conversions the
- * plain scalar nanosecond based representation can be selected by the
- * config switch CONFIG_KTIME_SCALAR.
- */
- typedef union {
- s64 tv64;
- #if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)
- struct {
- # ifdef __BIG_ENDIAN
- s32 sec, nsec;
- # else
- s32 nsec, sec;
- # endif
- } tv;
- #endif
- } ktime_t;
- #define KTIME_MAX ((s64)~((u64)1 << 63))
- #if (BITS_PER_LONG == 64)
- # define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC)
- #else
- # define KTIME_SEC_MAX LONG_MAX
- #endif
- /*
- * ktime_t definitions when using the 64-bit scalar representation:
- */
- #if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)
- /**
- * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
- * @secs: seconds to set
- * @nsecs: nanoseconds to set
- *
- * Return the ktime_t representation of the value
- */
- static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
- {
- #if (BITS_PER_LONG == 64)
- if (unlikely(secs >= KTIME_SEC_MAX))
- return (ktime_t){ .tv64 = KTIME_MAX };
- #endif
- return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };
- }
- /* Subtract two ktime_t variables. rem = lhs -rhs: */
- #define ktime_sub(lhs, rhs) \
- ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
- /* Add two ktime_t variables. res = lhs + rhs: */
- #define ktime_add(lhs, rhs) \
- ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
- /*
- * Add a ktime_t variable and a scalar nanosecond value.
- * res = kt + nsval:
- */
- #define ktime_add_ns(kt, nsval) \
- ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
- /* convert a timespec to ktime_t format: */
- static inline ktime_t timespec_to_ktime(struct timespec ts)
- {
- return ktime_set(ts.tv_sec, ts.tv_nsec);
- }
- /* convert a timeval to ktime_t format: */
- static inline ktime_t timeval_to_ktime(struct timeval tv)
- {
- return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
- }
- /* Map the ktime_t to timespec conversion to ns_to_timespec function */
- #define ktime_to_timespec(kt) ns_to_timespec((kt).tv64)
- /* Map the ktime_t to timeval conversion to ns_to_timeval function */
- #define ktime_to_timeval(kt) ns_to_timeval((kt).tv64)
- /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
- #define ktime_to_ns(kt) ((kt).tv64)
- #else
- /*
- * Helper macros/inlines to get the ktime_t math right in the timespec
- * representation. The macros are sometimes ugly - their actual use is
- * pretty okay-ish, given the circumstances. We do all this for
- * performance reasons. The pure scalar nsec_t based code was nice and
- * simple, but created too many 64-bit / 32-bit conversions and divisions.
- *
- * Be especially aware that negative values are represented in a way
- * that the tv.sec field is negative and the tv.nsec field is greater
- * or equal to zero but less than nanoseconds per second. This is the
- * same representation which is used by timespecs.
- *
- * tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC
- */
- /* Set a ktime_t variable to a value in sec/nsec representation: */
- static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
- {
- return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } };
- }
- /**
- * ktime_sub - subtract two ktime_t variables
- * @lhs: minuend
- * @rhs: subtrahend
- *
- * Returns the remainder of the substraction
- */
- static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs)
- {
- ktime_t res;
- res.tv64 = lhs.tv64 - rhs.tv64;
- if (res.tv.nsec < 0)
- res.tv.nsec += NSEC_PER_SEC;
- return res;
- }
- /**
- * ktime_add - add two ktime_t variables
- * @add1: addend1
- * @add2: addend2
- *
- * Returns the sum of @add1 and @add2.
- */
- static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2)
- {
- ktime_t res;
- res.tv64 = add1.tv64 + add2.tv64;
- /*
- * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx
- * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.
- *
- * it's equivalent to:
- * tv.nsec -= NSEC_PER_SEC
- * tv.sec ++;
- */
- if (res.tv.nsec >= NSEC_PER_SEC)
- res.tv64 += (u32)-NSEC_PER_SEC;
- return res;
- }
- /**
- * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
- * @kt: addend
- * @nsec: the scalar nsec value to add
- *
- * Returns the sum of @kt and @nsec in ktime_t format
- */
- extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec);
- /**
- * timespec_to_ktime - convert a timespec to ktime_t format
- * @ts: the timespec variable to convert
- *
- * Returns a ktime_t variable with the converted timespec value
- */
- static inline ktime_t timespec_to_ktime(const struct timespec ts)
- {
- return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec,
- .nsec = (s32)ts.tv_nsec } };
- }
- /**
- * timeval_to_ktime - convert a timeval to ktime_t format
- * @tv: the timeval variable to convert
- *
- * Returns a ktime_t variable with the converted timeval value
- */
- static inline ktime_t timeval_to_ktime(const struct timeval tv)
- {
- return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec,
- .nsec = (s32)tv.tv_usec * 1000 } };
- }
- /**
- * ktime_to_timespec - convert a ktime_t variable to timespec format
- * @kt: the ktime_t variable to convert
- *
- * Returns the timespec representation of the ktime value
- */
- static inline struct timespec ktime_to_timespec(const ktime_t kt)
- {
- return (struct timespec) { .tv_sec = (time_t) kt.tv.sec,
- .tv_nsec = (long) kt.tv.nsec };
- }
- /**
- * ktime_to_timeval - convert a ktime_t variable to timeval format
- * @kt: the ktime_t variable to convert
- *
- * Returns the timeval representation of the ktime value
- */
- static inline struct timeval ktime_to_timeval(const ktime_t kt)
- {
- return (struct timeval) {
- .tv_sec = (time_t) kt.tv.sec,
- .tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) };
- }
- /**
- * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds
- * @kt: the ktime_t variable to convert
- *
- * Returns the scalar nanoseconds representation of @kt
- */
- static inline s64 ktime_to_ns(const ktime_t kt)
- {
- return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec;
- }
- #endif
- /*
- * The resolution of the clocks. The resolution value is returned in
- * the clock_getres() system call to give application programmers an
- * idea of the (in)accuracy of timers. Timer values are rounded up to
- * this resolution values.
- */
- #define KTIME_LOW_RES (ktime_t){ .tv64 = TICK_NSEC }
- /* Get the monotonic time in timespec format: */
- extern void ktime_get_ts(struct timespec *ts);
- /* Get the real (wall-) time in timespec format: */
- #define ktime_get_real_ts(ts) getnstimeofday(ts)
- #endif
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