@@ -281,4 +281,17 @@ struct correlated_cs {
cycle_t cycles);
};
+/*
+ * 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 {
+ cycles_t cycles;
+ ktime_t real;
+ ktime_t raw;
+};
+
#endif /* _LINUX_CLOCKSOURCE_H */
@@ -301,6 +301,12 @@ struct sync_device_time_cb {
extern int get_device_system_crosststamp(struct sync_device_time_cb *cb,
struct system_device_crosststamp *ts);
+struct system_time_snapshot;
+/*
+ * Simultaneously snapshot realtime and monotonic raw clocks
+ */
+extern void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot);
+
/*
* Persistent clock related interfaces
*/
@@ -862,6 +862,37 @@ time64_t ktime_get_real_seconds(void)
}
EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
+/**
+ * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
+ * @systime_snapshot: pointer to struct receiving the system time snapshot
+ */
+void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
+{
+ struct timekeeper *tk = &tk_core.timekeeper;
+ unsigned long seq;
+ ktime_t base_raw;
+ ktime_t base_real;
+ s64 nsec_raw;
+ s64 nsec_real;
+ cycle_t now;
+
+ do {
+ seq = read_seqcount_begin(&tk_core.seq);
+
+ now = tk->tkr_mono.read(tk->tkr_mono.clock);
+ base_real = ktime_add(tk->tkr_mono.base,
+ tk_core.timekeeper.offs_real);
+ base_raw = tk->tkr_raw.base;
+ nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
+ nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
+ } while (read_seqcount_retry(&tk_core.seq, seq));
+
+ systime_snapshot->cycles = now;
+ systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
+ systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
+}
+EXPORT_SYMBOL_GPL(ktime_get_snapshot);
+
#ifdef CONFIG_NTP_PPS
/**
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. Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com> --- include/linux/clocksource.h | 13 +++++++++++++ include/linux/timekeeping.h | 6 ++++++ kernel/time/timekeeping.c | 31 +++++++++++++++++++++++++++++++ 3 files changed, 50 insertions(+)