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 <linux/time.h>
  25 #include <linux/jiffies.h>
  26
  27 /*
  28  * ktime_t:
  29  *
  30  * A single 64-bit variable is used to store the hrtimers
  31  * internal representation of time values in scalar nanoseconds. The
  32  * design plays out best on 64-bit CPUs, where most conversions are
  33  * NOPs and most arithmetic ktime_t operations are plain arithmetic
  34  * operations.
  35  *
  36  */
  37 union ktime {
  38         s64     tv64;
  39 };
  40
  41 typedef union ktime ktime_t;            /* Kill this */
  42
  43 /**
  44  * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
  45  * @secs:       seconds to set
  46  * @nsecs:      nanoseconds to set
  47  *
  48  * Return: The ktime_t representation of the value.
  49  */
  50 static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
  51 {
  52         if (unlikely(secs >= KTIME_SEC_MAX))
  53                 return (ktime_t){ .tv64 = KTIME_MAX };
  54
  55         return (ktime_t) { .tv64 = secs * NSEC_PER_SEC + (s64)nsecs };
  56 }
  57
  58 /* Subtract two ktime_t variables. rem = lhs -rhs: */
  59 #define ktime_sub(lhs, rhs) \
  60                 ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
  61
  62 /* Add two ktime_t variables. res = lhs + rhs: */
  63 #define ktime_add(lhs, rhs) \
  64                 ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
  65
  66 /*
  67  * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
  68  * this means that you must check the result for overflow yourself.
  69  */
  70 #define ktime_add_unsafe(lhs, rhs) \
  71                 ({ (ktime_t){ .tv64 = (u64) (lhs).tv64 + (rhs).tv64 }; })
  72
  73 /*
  74  * Add a ktime_t variable and a scalar nanosecond value.
  75  * res = kt + nsval:
  76  */
  77 #define ktime_add_ns(kt, nsval) \
  78                 ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
  79
  80 /*
  81  * Subtract a scalar nanosecod from a ktime_t variable
  82  * res = kt - nsval:
  83  */
  84 #define ktime_sub_ns(kt, nsval) \
  85                 ({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
  86
  87 /* convert a timespec to ktime_t format: */
  88 static inline ktime_t timespec_to_ktime(struct timespec ts)
  89 {
  90         return ktime_set(ts.tv_sec, ts.tv_nsec);
  91 }
  92
  93 /* convert a timespec64 to ktime_t format: */
  94 static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
  95 {
  96         return ktime_set(ts.tv_sec, ts.tv_nsec);
  97 }
  98
  99 /* convert a timeval to ktime_t format: */
 100 static inline ktime_t timeval_to_ktime(struct timeval tv)
 101 {
 102         return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
 103 }
 104
 105 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
 106 #define ktime_to_timespec(kt)           ns_to_timespec((kt).tv64)
 107
 108 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
 109 #define ktime_to_timespec64(kt)         ns_to_timespec64((kt).tv64)
 110
 111 /* Map the ktime_t to timeval conversion to ns_to_timeval function */
 112 #define ktime_to_timeval(kt)            ns_to_timeval((kt).tv64)
 113
 114 /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
 115 #define ktime_to_ns(kt)                 ((kt).tv64)
 116
 117
 118 /**
 119  * ktime_equal - Compares two ktime_t variables to see if they are equal
 120  * @cmp1:       comparable1
 121  * @cmp2:       comparable2
 122  *
 123  * Compare two ktime_t variables.
 124  *
 125  * Return: 1 if equal.
 126  */
 127 static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
 128 {
 129         return cmp1.tv64 == cmp2.tv64;
 130 }
 131
 132 /**
 133  * ktime_compare - Compares two ktime_t variables for less, greater or equal
 134  * @cmp1:       comparable1
 135  * @cmp2:       comparable2
 136  *
 137  * Return: ...
 138  *   cmp1  < cmp2: return <0
 139  *   cmp1 == cmp2: return 0
 140  *   cmp1  > cmp2: return >0
 141  */
 142 static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
 143 {
 144         if (cmp1.tv64 < cmp2.tv64)
 145                 return -1;
 146         if (cmp1.tv64 > cmp2.tv64)
 147                 return 1;
 148         return 0;
 149 }
 150
 151 /**
 152  * ktime_after - Compare if a ktime_t value is bigger than another one.
 153  * @cmp1:       comparable1
 154  * @cmp2:       comparable2
 155  *
 156  * Return: true if cmp1 happened after cmp2.
 157  */
 158 static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
 159 {
 160         return ktime_compare(cmp1, cmp2) > 0;
 161 }
 162
 163 /**
 164  * ktime_before - Compare if a ktime_t value is smaller than another one.
 165  * @cmp1:       comparable1
 166  * @cmp2:       comparable2
 167  *
 168  * Return: true if cmp1 happened before cmp2.
 169  */
 170 static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
 171 {
 172         return ktime_compare(cmp1, cmp2) < 0;
 173 }
 174
 175 #if BITS_PER_LONG < 64
 176 extern s64 __ktime_divns(const ktime_t kt, s64 div);
 177 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 178 {
 179         /*
 180          * Negative divisors could cause an inf loop,
 181          * so bug out here.
 182          */
 183         BUG_ON(div < 0);
 184         if (__builtin_constant_p(div) && !(div >> 32)) {
 185                 s64 ns = kt.tv64;
 186                 u64 tmp = ns < 0 ? -ns : ns;
 187
 188                 do_div(tmp, div);
 189                 return ns < 0 ? -tmp : tmp;
 190         } else {
 191                 return __ktime_divns(kt, div);
 192         }
 193 }
 194 #else /* BITS_PER_LONG < 64 */
 195 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 196 {
 197         /*
 198          * 32-bit implementation cannot handle negative divisors,
 199          * so catch them on 64bit as well.
 200          */
 201         WARN_ON(div < 0);
 202         return kt.tv64 / div;
 203 }
 204 #endif
 205
 206 static inline s64 ktime_to_us(const ktime_t kt)
 207 {
 208         return ktime_divns(kt, NSEC_PER_USEC);
 209 }
 210
 211 static inline s64 ktime_to_ms(const ktime_t kt)
 212 {
 213         return ktime_divns(kt, NSEC_PER_MSEC);
 214 }
 215
 216 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
 217 {
 218        return ktime_to_us(ktime_sub(later, earlier));
 219 }
 220
 221 static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
 222 {
 223         return ktime_to_ms(ktime_sub(later, earlier));
 224 }
 225
 226 static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
 227 {
 228         return ktime_add_ns(kt, usec * NSEC_PER_USEC);
 229 }
 230
 231 static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
 232 {
 233         return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
 234 }
 235
 236 static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
 237 {
 238         return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
 239 }
 240
 241 static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
 242 {
 243         return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
 244 }
 245
 246 extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
 247
 248 /**
 249  * ktime_to_timespec_cond - convert a ktime_t variable to timespec
 250  *                          format only if the variable contains data
 251  * @kt:         the ktime_t variable to convert
 252  * @ts:         the timespec variable to store the result in
 253  *
 254  * Return: %true if there was a successful conversion, %false if kt was 0.
 255  */
 256 static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
 257                                                        struct timespec *ts)
 258 {
 259         if (kt.tv64) {
 260                 *ts = ktime_to_timespec(kt);
 261                 return true;
 262         } else {
 263                 return false;
 264         }
 265 }
 266
 267 /**
 268  * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
 269  *                          format only if the variable contains data
 270  * @kt:         the ktime_t variable to convert
 271  * @ts:         the timespec variable to store the result in
 272  *
 273  * Return: %true if there was a successful conversion, %false if kt was 0.
 274  */
 275 static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
 276                                                        struct timespec64 *ts)
 277 {
 278         if (kt.tv64) {
 279                 *ts = ktime_to_timespec64(kt);
 280                 return true;
 281         } else {
 282                 return false;
 283         }
 284 }
 285
 286 /*
 287  * The resolution of the clocks. The resolution value is returned in
 288  * the clock_getres() system call to give application programmers an
 289  * idea of the (in)accuracy of timers. Timer values are rounded up to
 290  * this resolution values.
 291  */
 292 #define LOW_RES_NSEC            TICK_NSEC
 293 #define KTIME_LOW_RES           (ktime_t){ .tv64 = LOW_RES_NSEC }
 294
 295 static inline ktime_t ns_to_ktime(u64 ns)
 296 {
 297         static const ktime_t ktime_zero = { .tv64 = 0 };
 298
 299         return ktime_add_ns(ktime_zero, ns);
 300 }
 301
 302 static inline ktime_t ms_to_ktime(u64 ms)
 303 {
 304         static const ktime_t ktime_zero = { .tv64 = 0 };
 305
 306         return ktime_add_ms(ktime_zero, ms);
 307 }
 308
 309 # include <linux/timekeeping.h>
 310
 311 #endif