226 	u64 now;  in msr_read_counter()  local
229 		rdmsrl(event->hw.event_base, now);  in msr_read_counter()
231 		now = rdtsc_ordered();  in msr_read_counter()
233 	return now;  in msr_read_counter()
238 	u64 prev, now;  in msr_event_update()  local
244 	now = msr_read_counter(event);  in msr_event_update()
246 	if (local64_cmpxchg(&event->hw.prev_count, prev, now) != prev)  in msr_event_update()
249 	delta = now - prev;  in msr_event_update()
255 		now = now & (1ULL << 31) ? (now >> 16) & 0x3f :  -1;  in msr_event_update()
256 		local64_set(&event->count, now);  in msr_event_update()
264 	u64 now = msr_read_counter(event);  in msr_event_start()  local
266 	local64_set(&event->hw.prev_count, now);  in msr_event_start()