arch/x86/kernel/trace_clock.c

   1 /*
   2  * X86 trace clocks
   3  */
   4 #include <asm/trace_clock.h>
   5 #include <asm/barrier.h>
   6 #include <asm/msr.h>
   7
   8 /*
   9  * trace_clock_x86_tsc(): A clock that is just the cycle counter.
  10  *
  11  * Unlike the other clocks, this is not in nanoseconds.
  12  */
  13 u64 notrace trace_clock_x86_tsc(void)
  14 {
  15         u64 ret;
  16
  17         rdtsc_barrier();
  18         rdtscll(ret);
  19
  20         return ret;
  21 }