static uint64_t
rtc_nanotime_read(void)
{
	rtc_nanotime_t	rnt, *rntp = &rtc_nanotime_info;
	uint64_t		result;

	do {
		rtc_nanotime_load(rntp, &rnt);
		result = rnt.ns_base + _tsc_to_nanoseconds(rdtsc64() - rnt.tsc_base);
	} while (rntp->tsc_base != rnt.tsc_base);

	return (result);
}