time: Add timekeeping snapshot code capturing system time and counter
In the current timekeeping code there isn't any interface to
atomically capture the current relationship between the system counter
and system time. ktime_get_snapshot() returns this triple (counter,
monotonic raw, realtime) in the system_time_snapshot struct.
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
[jstultz: Moved structure definitions around to clean things up,
fixed cycles_t/cycle_t confusion.]
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index ec89d84..7817591 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -267,6 +267,24 @@
struct timespec64 *ts_real);
/*
+ * struct system_time_snapshot - simultaneous raw/real time capture with
+ * counter value
+ * @cycles: Clocksource counter value to produce the system times
+ * @real: Realtime system time
+ * @raw: Monotonic raw system time
+ */
+struct system_time_snapshot {
+ cycle_t cycles;
+ ktime_t real;
+ ktime_t raw;
+};
+
+/*
+ * Simultaneously snapshot realtime and monotonic raw clocks
+ */
+extern void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot);
+
+/*
* Persistent clock related interfaces
*/
extern int persistent_clock_is_local;