include/linux/ktime.h

   1 /*
   2  *  include/linux/ktime.h
   3  *
   4  *  ktime_t - nanosecond-resolution time format.
   5  *
   6  *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
   7  *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
   8  *
   9  *  data type definitions, declarations, prototypes and macros.
  10  *
  11  *  Started by: Thomas Gleixner and Ingo Molnar
  12  *
  13  *  Credits:
  14  *
  15  *      Roman Zippel provided the ideas and primary code snippets of
  16  *      the ktime_t union and further simplifications of the original
  17  *      code.
  18  *
  19  *  For licencing details see kernel-base/COPYING
  20  */
  21 #ifndef _LINUX_KTIME_H
  22 #define _LINUX_KTIME_H
  23
  24 #include <asm/bug.h>
  25 #include <linux/jiffies.h>
  26 #include <linux/time.h>
  27 #include <linux/types.h>
  28
  29 /**
  30  * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
  31  * @secs:       seconds to set
  32  * @nsecs:      nanoseconds to set
  33  *
  34  * Return: The ktime_t representation of the value.
  35  */
  36 static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
  37 {
  38         if (unlikely(secs >= KTIME_SEC_MAX))
  39                 return KTIME_MAX;
  40
  41         return secs * NSEC_PER_SEC + (s64)nsecs;
  42 }
  43
  44 /* Subtract two ktime_t variables. rem = lhs -rhs: */
  45 #define ktime_sub(lhs, rhs)     ((lhs) - (rhs))
  46
  47 /* Add two ktime_t variables. res = lhs + rhs: */
  48 #define ktime_add(lhs, rhs)     ((lhs) + (rhs))
  49
  50 /*
  51  * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
  52  * this means that you must check the result for overflow yourself.
  53  */
  54 #define ktime_add_unsafe(lhs, rhs)      ((u64) (lhs) + (rhs))
  55
  56 /*
  57  * Add a ktime_t variable and a scalar nanosecond value.
  58  * res = kt + nsval:
  59  */
  60 #define ktime_add_ns(kt, nsval)         ((kt) + (nsval))
  61
  62 /*
  63  * Subtract a scalar nanosecod from a ktime_t variable
  64  * res = kt - nsval:
  65  */
  66 #define ktime_sub_ns(kt, nsval)         ((kt) - (nsval))
  67
  68 /* convert a timespec64 to ktime_t format: */
  69 static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
  70 {
  71         return ktime_set(ts.tv_sec, ts.tv_nsec);
  72 }
  73
  74 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
  75 #define ktime_to_timespec64(kt)         ns_to_timespec64((kt))
  76
  77 /* Convert ktime_t to nanoseconds */
  78 static inline s64 ktime_to_ns(const ktime_t kt)
  79 {
  80         return kt;
  81 }
  82
  83 /**
  84  * ktime_compare - Compares two ktime_t variables for less, greater or equal
  85  * @cmp1:       comparable1
  86  * @cmp2:       comparable2
  87  *
  88  * Return: ...
  89  *   cmp1  < cmp2: return <0
  90  *   cmp1 == cmp2: return 0
  91  *   cmp1  > cmp2: return >0
  92  */
  93 static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
  94 {
  95         if (cmp1 < cmp2)
  96                 return -1;
  97         if (cmp1 > cmp2)
  98                 return 1;
  99         return 0;
 100 }
 101
 102 /**
 103  * ktime_after - Compare if a ktime_t value is bigger than another one.
 104  * @cmp1:       comparable1
 105  * @cmp2:       comparable2
 106  *
 107  * Return: true if cmp1 happened after cmp2.
 108  */
 109 static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
 110 {
 111         return ktime_compare(cmp1, cmp2) > 0;
 112 }
 113
 114 /**
 115  * ktime_before - Compare if a ktime_t value is smaller than another one.
 116  * @cmp1:       comparable1
 117  * @cmp2:       comparable2
 118  *
 119  * Return: true if cmp1 happened before cmp2.
 120  */
 121 static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
 122 {
 123         return ktime_compare(cmp1, cmp2) < 0;
 124 }
 125
 126 #if BITS_PER_LONG < 64
 127 extern s64 __ktime_divns(const ktime_t kt, s64 div);
 128 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 129 {
 130         /*
 131          * Negative divisors could cause an inf loop,
 132          * so bug out here.
 133          */
 134         BUG_ON(div < 0);
 135         if (__builtin_constant_p(div) && !(div >> 32)) {
 136                 s64 ns = kt;
 137                 u64 tmp = ns < 0 ? -ns : ns;
 138
 139                 do_div(tmp, div);
 140                 return ns < 0 ? -tmp : tmp;
 141         } else {
 142                 return __ktime_divns(kt, div);
 143         }
 144 }
 145 #else /* BITS_PER_LONG < 64 */
 146 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 147 {
 148         /*
 149          * 32-bit implementation cannot handle negative divisors,
 150          * so catch them on 64bit as well.
 151          */
 152         WARN_ON(div < 0);
 153         return kt / div;
 154 }
 155 #endif
 156
 157 static inline s64 ktime_to_us(const ktime_t kt)
 158 {
 159         return ktime_divns(kt, NSEC_PER_USEC);
 160 }
 161
 162 static inline s64 ktime_to_ms(const ktime_t kt)
 163 {
 164         return ktime_divns(kt, NSEC_PER_MSEC);
 165 }
 166
 167 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
 168 {
 169        return ktime_to_us(ktime_sub(later, earlier));
 170 }
 171
 172 static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
 173 {
 174         return ktime_to_ms(ktime_sub(later, earlier));
 175 }
 176
 177 static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
 178 {
 179         return ktime_add_ns(kt, usec * NSEC_PER_USEC);
 180 }
 181
 182 static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
 183 {
 184         return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
 185 }
 186
 187 static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
 188 {
 189         return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
 190 }
 191
 192 static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
 193 {
 194         return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
 195 }
 196
 197 extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
 198
 199 /**
 200  * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
 201  *                          format only if the variable contains data
 202  * @kt:         the ktime_t variable to convert
 203  * @ts:         the timespec variable to store the result in
 204  *
 205  * Return: %true if there was a successful conversion, %false if kt was 0.
 206  */
 207 static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
 208                                                        struct timespec64 *ts)
 209 {
 210         if (kt) {
 211                 *ts = ktime_to_timespec64(kt);
 212                 return true;
 213         } else {
 214                 return false;
 215         }
 216 }
 217
 218 #include <vdso/ktime.h>
 219
 220 static inline ktime_t ns_to_ktime(u64 ns)
 221 {
 222         return ns;
 223 }
 224
 225 static inline ktime_t ms_to_ktime(u64 ms)
 226 {
 227         return ms * NSEC_PER_MSEC;
 228 }
 229
 230 # include <linux/timekeeping.h>
 231
 232 #endif