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
   8 typedef __s64 time64_t;
   9 typedef __u64 timeu64_t;
  10
  11 #include <uapi/linux/time.h>
  12
  13 struct timespec64 {
  14         time64_t        tv_sec;                 /* seconds */
  15         long            tv_nsec;                /* nanoseconds */
  16 };
  17
  18 struct itimerspec64 {
  19         struct timespec64 it_interval;
  20         struct timespec64 it_value;
  21 };
  22
  23 /* Parameters used to convert the timespec values: */
  24 #define PSEC_PER_NSEC                   1000L
  25
  26 /* Located here for timespec[64]_valid_strict */
  27 #define TIME64_MAX                      ((s64)~((u64)1 << 63))
  28 #define TIME64_MIN                      (-TIME64_MAX - 1)
  29
  30 #define KTIME_MAX                       ((s64)~((u64)1 << 63))
  31 #define KTIME_MIN                       (-KTIME_MAX - 1)
  32 #define KTIME_SEC_MAX                   (KTIME_MAX / NSEC_PER_SEC)
  33 #define KTIME_SEC_MIN                   (KTIME_MIN / NSEC_PER_SEC)
  34
  35 /*
  36  * Limits for settimeofday():
  37  *
  38  * To prevent setting the time close to the wraparound point time setting
  39  * is limited so a reasonable uptime can be accomodated. Uptime of 30 years
  40  * should be really sufficient, which means the cutoff is 2232. At that
  41  * point the cutoff is just a small part of the larger problem.
  42  */
  43 #define TIME_UPTIME_SEC_MAX             (30LL * 365 * 24 *3600)
  44 #define TIME_SETTOD_SEC_MAX             (KTIME_SEC_MAX - TIME_UPTIME_SEC_MAX)
  45
  46 static inline int timespec64_equal(const struct timespec64 *a,
  47                                    const struct timespec64 *b)
  48 {
  49         return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
  50 }
  51
  52 static inline bool timespec64_is_epoch(const struct timespec64 *ts)
  53 {
  54         return ts->tv_sec == 0 && ts->tv_nsec == 0;
  55 }
  56
  57 /*
  58  * lhs < rhs:  return <0
  59  * lhs == rhs: return 0
  60  * lhs > rhs:  return >0
  61  */
  62 static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *rhs)
  63 {
  64         if (lhs->tv_sec < rhs->tv_sec)
  65                 return -1;
  66         if (lhs->tv_sec > rhs->tv_sec)
  67                 return 1;
  68         return lhs->tv_nsec - rhs->tv_nsec;
  69 }
  70
  71 extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
  72
  73 static inline struct timespec64 timespec64_add(struct timespec64 lhs,
  74                                                 struct timespec64 rhs)
  75 {
  76         struct timespec64 ts_delta;
  77         set_normalized_timespec64(&ts_delta, lhs.tv_sec + rhs.tv_sec,
  78                                 lhs.tv_nsec + rhs.tv_nsec);
  79         return ts_delta;
  80 }
  81
  82 /*
  83  * sub = lhs - rhs, in normalized form
  84  */
  85 static inline struct timespec64 timespec64_sub(struct timespec64 lhs,
  86                                                 struct timespec64 rhs)
  87 {
  88         struct timespec64 ts_delta;
  89         set_normalized_timespec64(&ts_delta, lhs.tv_sec - rhs.tv_sec,
  90                                 lhs.tv_nsec - rhs.tv_nsec);
  91         return ts_delta;
  92 }
  93
  94 /*
  95  * Returns true if the timespec64 is norm, false if denorm:
  96  */
  97 static inline bool timespec64_valid(const struct timespec64 *ts)
  98 {
  99         /* Dates before 1970 are bogus */
 100         if (ts->tv_sec < 0)
 101                 return false;
 102         /* Can't have more nanoseconds then a second */
 103         if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
 104                 return false;
 105         return true;
 106 }
 107
 108 static inline bool timespec64_valid_strict(const struct timespec64 *ts)
 109 {
 110         if (!timespec64_valid(ts))
 111                 return false;
 112         /* Disallow values that could overflow ktime_t */
 113         if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
 114                 return false;
 115         return true;
 116 }
 117
 118 static inline bool timespec64_valid_settod(const struct timespec64 *ts)
 119 {
 120         if (!timespec64_valid(ts))
 121                 return false;
 122         /* Disallow values which cause overflow issues vs. CLOCK_REALTIME */
 123         if ((unsigned long long)ts->tv_sec >= TIME_SETTOD_SEC_MAX)
 124                 return false;
 125         return true;
 126 }
 127
 128 /**
 129  * timespec64_to_ns - Convert timespec64 to nanoseconds
 130  * @ts:         pointer to the timespec64 variable to be converted
 131  *
 132  * Returns the scalar nanosecond representation of the timespec64
 133  * parameter.
 134  */
 135 static inline s64 timespec64_to_ns(const struct timespec64 *ts)
 136 {
 137         /* Prevent multiplication overflow / underflow */
 138         if (ts->tv_sec >= KTIME_SEC_MAX)
 139                 return KTIME_MAX;
 140
 141         if (ts->tv_sec <= KTIME_SEC_MIN)
 142                 return KTIME_MIN;
 143
 144         return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
 145 }
 146
 147 /**
 148  * ns_to_timespec64 - Convert nanoseconds to timespec64
 149  * @nsec:       the nanoseconds value to be converted
 150  *
 151  * Returns the timespec64 representation of the nsec parameter.
 152  */
 153 extern struct timespec64 ns_to_timespec64(s64 nsec);
 154
 155 /**
 156  * timespec64_add_ns - Adds nanoseconds to a timespec64
 157  * @a:          pointer to timespec64 to be incremented
 158  * @ns:         unsigned nanoseconds value to be added
 159  *
 160  * This must always be inlined because its used from the x86-64 vdso,
 161  * which cannot call other kernel functions.
 162  */
 163 static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
 164 {
 165         a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
 166         a->tv_nsec = ns;
 167 }
 168
 169 /*
 170  * timespec64_add_safe assumes both values are positive and checks for
 171  * overflow. It will return TIME64_MAX in case of overflow.
 172  */
 173 extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
 174                                          const struct timespec64 rhs);
 175
 176 #endif /* _LINUX_TIME64_H */