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
   7 typedef __s64 time64_t;
   8 typedef __u64 timeu64_t;
   9
  10 #include <uapi/linux/time.h>
  11
  12 struct timespec64 {
  13         time64_t        tv_sec;                 /* seconds */
  14         long            tv_nsec;                /* nanoseconds */
  15 };
  16
  17 struct 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
  49 static 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  */
  60 static 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
  69 extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
  70
  71 static 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  */
  83 static 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  */
  95 static 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
 106 static 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
 116 static 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  */
 133 static 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  */
 144 extern 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  */
 154 static __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  */
 164 extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
 165                                          const struct timespec64 rhs);
 166
 167 #endif /* _LINUX_TIME64_H */