LXR linux/include/linux/time64.h

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