kernel/time/timekeeping_internal.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _TIMEKEEPING_INTERNAL_H
   3 #define _TIMEKEEPING_INTERNAL_H
   4
   5 #include <linux/clocksource.h>
   6 #include <linux/spinlock.h>
   7 #include <linux/time.h>
   8
   9 /*
  10  * timekeeping debug functions
  11  */
  12 #ifdef CONFIG_DEBUG_FS
  13 extern void tk_debug_account_sleep_time(const struct timespec64 *t);
  14 #else
  15 #define tk_debug_account_sleep_time(x)
  16 #endif
  17
  18 #ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE
  19 static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
  20 {
  21         u64 ret = (now - last) & mask;
  22
  23         /*
  24          * Prevent time going backwards by checking the MSB of mask in
  25          * the result. If set, return 0.
  26          */
  27         return ret & ~(mask >> 1) ? 0 : ret;
  28 }
  29 #else
  30 static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
  31 {
  32         return (now - last) & mask;
  33 }
  34 #endif
  35
  36 /* Semi public for serialization of non timekeeper VDSO updates. */
  37 extern raw_spinlock_t timekeeper_lock;
  38
  39 #endif /* _TIMEKEEPING_INTERNAL_H */