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