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 /* Nanosecond scalar representation for kernel time values */
  28 typedef s64     ktime_t;
  29
  30 /**
  31  * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
  32  * @secs:       seconds to set
  33  * @nsecs:      nanoseconds to set
  34  *
  35  * Return: The ktime_t representation of the value.
  36  */
  37 static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
  38 {
  39         if (unlikely(secs >= KTIME_SEC_MAX))
  40                 return KTIME_MAX;
  41
  42         return secs * NSEC_PER_SEC + (s64)nsecs;
  43 }
  44
  45 /* Subtract two ktime_t variables. rem = lhs -rhs: */
  46 #define ktime_sub(lhs, rhs)     ((lhs) - (rhs))
  47
  48 /* Add two ktime_t variables. res = lhs + rhs: */
  49 #define ktime_add(lhs, rhs)     ((lhs) + (rhs))
  50
  51 /*
  52  * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
  53  * this means that you must check the result for overflow yourself.
  54  */
  55 #define ktime_add_unsafe(lhs, rhs)      ((u64) (lhs) + (rhs))
  56
  57 /*
  58  * Add a ktime_t variable and a scalar nanosecond value.
  59  * res = kt + nsval:
  60  */
  61 #define ktime_add_ns(kt, nsval)         ((kt) + (nsval))
  62
  63 /*
  64  * Subtract a scalar nanosecod from a ktime_t variable
  65  * res = kt - nsval:
  66  */
  67 #define ktime_sub_ns(kt, nsval)         ((kt) - (nsval))
  68
  69 /* convert a timespec64 to ktime_t format: */
  70 static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
  71 {
  72         return ktime_set(ts.tv_sec, ts.tv_nsec);
  73 }
  74
  75 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
  76 #define ktime_to_timespec64(kt)         ns_to_timespec64((kt))
  77
  78 /* Convert ktime_t to nanoseconds */
  79 static inline s64 ktime_to_ns(const ktime_t kt)
  80 {
  81         return kt;
  82 }
  83
  84 /**
  85  * ktime_compare - Compares two ktime_t variables for less, greater or equal
  86  * @cmp1:       comparable1
  87  * @cmp2:       comparable2
  88  *
  89  * Return: ...
  90  *   cmp1  < cmp2: return <0
  91  *   cmp1 == cmp2: return 0
  92  *   cmp1  > cmp2: return >0
  93  */
  94 static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
  95 {
  96         if (cmp1 < cmp2)
  97                 return -1;
  98         if (cmp1 > cmp2)
  99                 return 1;
 100         return 0;
 101 }
 102
 103 /**
 104  * ktime_after - Compare if a ktime_t value is bigger than another one.
 105  * @cmp1:       comparable1
 106  * @cmp2:       comparable2
 107  *
 108  * Return: true if cmp1 happened after cmp2.
 109  */
 110 static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
 111 {
 112         return ktime_compare(cmp1, cmp2) > 0;
 113 }
 114
 115 /**
 116  * ktime_before - Compare if a ktime_t value is smaller than another one.
 117  * @cmp1:       comparable1
 118  * @cmp2:       comparable2
 119  *
 120  * Return: true if cmp1 happened before cmp2.
 121  */
 122 static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
 123 {
 124         return ktime_compare(cmp1, cmp2) < 0;
 125 }
 126
 127 #if BITS_PER_LONG < 64
 128 extern s64 __ktime_divns(const ktime_t kt, s64 div);
 129 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 130 {
 131         /*
 132          * Negative divisors could cause an inf loop,
 133          * so bug out here.
 134          */
 135         BUG_ON(div < 0);
 136         if (__builtin_constant_p(div) && !(div >> 32)) {
 137                 s64 ns = kt;
 138                 u64 tmp = ns < 0 ? -ns : ns;
 139
 140                 do_div(tmp, div);
 141                 return ns < 0 ? -tmp : tmp;
 142         } else {
 143                 return __ktime_divns(kt, div);
 144         }
 145 }
 146 #else /* BITS_PER_LONG < 64 */
 147 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 148 {
 149         /*
 150          * 32-bit implementation cannot handle negative divisors,
 151          * so catch them on 64bit as well.
 152          */
 153         WARN_ON(div < 0);
 154         return kt / div;
 155 }
 156 #endif
 157
 158 static inline s64 ktime_to_us(const ktime_t kt)
 159 {
 160         return ktime_divns(kt, NSEC_PER_USEC);
 161 }
 162
 163 static inline s64 ktime_to_ms(const ktime_t kt)
 164 {
 165         return ktime_divns(kt, NSEC_PER_MSEC);
 166 }
 167
 168 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
 169 {
 170        return ktime_to_us(ktime_sub(later, earlier));
 171 }
 172
 173 static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
 174 {
 175         return ktime_to_ms(ktime_sub(later, earlier));
 176 }
 177
 178 static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
 179 {
 180         return ktime_add_ns(kt, usec * NSEC_PER_USEC);
 181 }
 182
 183 static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
 184 {
 185         return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
 186 }
 187
 188 static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
 189 {
 190         return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
 191 }
 192
 193 static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
 194 {
 195         return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
 196 }
 197
 198 extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
 199
 200 /**
 201  * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
 202  *                          format only if the variable contains data
 203  * @kt:         the ktime_t variable to convert
 204  * @ts:         the timespec variable to store the result in
 205  *
 206  * Return: %true if there was a successful conversion, %false if kt was 0.
 207  */
 208 static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
 209                                                        struct timespec64 *ts)
 210 {
 211         if (kt) {
 212                 *ts = ktime_to_timespec64(kt);
 213                 return true;
 214         } else {
 215                 return false;
 216         }
 217 }
 218
 219 #include <vdso/ktime.h>
 220
 221 static inline ktime_t ns_to_ktime(u64 ns)
 222 {
 223         return ns;
 224 }
 225
 226 static inline ktime_t ms_to_ktime(u64 ms)
 227 {
 228         return ms * NSEC_PER_MSEC;
 229 }
 230
 231 # include <linux/timekeeping.h>
 232 # include <linux/timekeeping32.h>
 233
 234 #endif