linux/include/linux/time64.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_TIME64_H
   3#define _LINUX_TIME64_H
   4
   5#include <linux/math64.h>
   6
   7typedef __s64 time64_t;
   8typedef __u64 timeu64_t;
   9
  10#include <uapi/linux/time.h>
  11
  12struct timespec64 {
  13        time64_t        tv_sec;                 /* seconds */
  14        long            tv_nsec;                /* nanoseconds */
  15};
  16
  17struct itimerspec64 {
  18        struct timespec64 it_interval;
  19        struct timespec64 it_value;
  20};
  21
  22/* Parameters used to convert the timespec values: */
  23#define MSEC_PER_SEC    1000L
  24#define USEC_PER_MSEC   1000L
  25#define NSEC_PER_USEC   1000L
  26#define NSEC_PER_MSEC   1000000L
  27#define USEC_PER_SEC    1000000L
  28#define NSEC_PER_SEC    1000000000L
  29#define FSEC_PER_SEC    1000000000000000LL
  30
  31/* Located here for timespec[64]_valid_strict */
  32#define TIME64_MAX                      ((s64)~((u64)1 << 63))
  33#define TIME64_MIN                      (-TIME64_MAX - 1)
  34
  35#define KTIME_MAX                       ((s64)~((u64)1 << 63))
  36#define KTIME_SEC_MAX                   (KTIME_MAX / NSEC_PER_SEC)
  37
  38/*
  39 * Limits for settimeofday():
  40 *
  41 * To prevent setting the time close to the wraparound point time setting
  42 * is limited so a reasonable uptime can be accomodated. Uptime of 30 years
  43 * should be really sufficient, which means the cutoff is 2232. At that
  44 * point the cutoff is just a small part of the larger problem.
  45 */
  46#define TIME_UPTIME_SEC_MAX             (30LL * 365 * 24 *3600)
  47#define TIME_SETTOD_SEC_MAX             (KTIME_SEC_MAX - TIME_UPTIME_SEC_MAX)
  48
  49static inline int timespec64_equal(const struct timespec64 *a,
  50                                   const struct timespec64 *b)
  51{
  52        return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
  53}
  54
  55/*
  56 * lhs < rhs:  return <0
  57 * lhs == rhs: return 0
  58 * lhs > rhs:  return >0
  59 */
  60static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *rhs)
  61{
  62        if (lhs->tv_sec < rhs->tv_sec)
  63                return -1;
  64        if (lhs->tv_sec > rhs->tv_sec)
  65                return 1;
  66        return lhs->tv_nsec - rhs->tv_nsec;
  67}
  68
  69extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
  70
  71static inline struct timespec64 timespec64_add(struct timespec64 lhs,
  72                                                struct timespec64 rhs)
  73{
  74        struct timespec64 ts_delta;
  75        set_normalized_timespec64(&ts_delta, lhs.tv_sec + rhs.tv_sec,
  76                                lhs.tv_nsec + rhs.tv_nsec);
  77        return ts_delta;
  78}
  79
  80/*
  81 * sub = lhs - rhs, in normalized form
  82 */
  83static inline struct timespec64 timespec64_sub(struct timespec64 lhs,
  84                                                struct timespec64 rhs)
  85{
  86        struct timespec64 ts_delta;
  87        set_normalized_timespec64(&ts_delta, lhs.tv_sec - rhs.tv_sec,
  88                                lhs.tv_nsec - rhs.tv_nsec);
  89        return ts_delta;
  90}
  91
  92/*
  93 * Returns true if the timespec64 is norm, false if denorm:
  94 */
  95static inline bool timespec64_valid(const struct timespec64 *ts)
  96{
  97        /* Dates before 1970 are bogus */
  98        if (ts->tv_sec < 0)
  99                return false;
 100        /* Can't have more nanoseconds then a second */
 101        if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
 102                return false;
 103        return true;
 104}
 105
 106static inline bool timespec64_valid_strict(const struct timespec64 *ts)
 107{
 108        if (!timespec64_valid(ts))
 109                return false;
 110        /* Disallow values that could overflow ktime_t */
 111        if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
 112                return false;
 113        return true;
 114}
 115
 116static inline bool timespec64_valid_settod(const struct timespec64 *ts)
 117{
 118        if (!timespec64_valid(ts))
 119                return false;
 120        /* Disallow values which cause overflow issues vs. CLOCK_REALTIME */
 121        if ((unsigned long long)ts->tv_sec >= TIME_SETTOD_SEC_MAX)
 122                return false;
 123        return true;
 124}
 125
 126/**
 127 * timespec64_to_ns - Convert timespec64 to nanoseconds
 128 * @ts:         pointer to the timespec64 variable to be converted
 129 *
 130 * Returns the scalar nanosecond representation of the timespec64
 131 * parameter.
 132 */
 133static inline s64 timespec64_to_ns(const struct timespec64 *ts)
 134{
 135        return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
 136}
 137
 138/**
 139 * ns_to_timespec64 - Convert nanoseconds to timespec64
 140 * @nsec:       the nanoseconds value to be converted
 141 *
 142 * Returns the timespec64 representation of the nsec parameter.
 143 */
 144extern struct timespec64 ns_to_timespec64(const s64 nsec);
 145
 146/**
 147 * timespec64_add_ns - Adds nanoseconds to a timespec64
 148 * @a:          pointer to timespec64 to be incremented
 149 * @ns:         unsigned nanoseconds value to be added
 150 *
 151 * This must always be inlined because its used from the x86-64 vdso,
 152 * which cannot call other kernel functions.
 153 */
 154static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
 155{
 156        a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
 157        a->tv_nsec = ns;
 158}
 159
 160/*
 161 * timespec64_add_safe assumes both values are positive and checks for
 162 * overflow. It will return TIME64_MAX in case of overflow.
 163 */
 164extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
 165                                         const struct timespec64 rhs);
 166
 167#endif /* _LINUX_TIME64_H */
 168