time: Introduce current_kernel_time64()

The current_kernel_time() is not year 2038 safe on 32bit systems
since it returns a timespec value. Introduce current_kernel_time64()
which returns a timespec64 value.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NBaolin Wang <baolin.wang@linaro.org>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

include/linux/timekeeping.h

@@ -18,10 +18,17 @@ extern int do_sys_settimeofday(const struct timespec *tv,
  * Kernel time accessors
  */
 unsigned long get_seconds(void);
-struct timespec current_kernel_time(void);
+struct timespec64 current_kernel_time64(void);
 /* does not take xtime_lock */
 struct timespec __current_kernel_time(void);
 
+static inline struct timespec current_kernel_time(void)
+{
+	struct timespec64 now = current_kernel_time64();
+
+	return timespec64_to_timespec(now);
+}
+
 /*
  * timespec based interfaces
  */

kernel/time/timekeeping.c

@@ -1881,7 +1881,7 @@ struct timespec __current_kernel_time(void)
 	return timespec64_to_timespec(tk_xtime(tk));
 }
 
-struct timespec current_kernel_time(void)
+struct timespec64 current_kernel_time64(void)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
 	struct timespec64 now;
@@ -1893,9 +1893,9 @@ struct timespec current_kernel_time(void)
 		now = tk_xtime(tk);
 	} while (read_seqcount_retry(&tk_core.seq, seq));
 
-	return timespec64_to_timespec(now);
+	return now;
 }
-EXPORT_SYMBOL(current_kernel_time);
+EXPORT_SYMBOL(current_kernel_time64);
 
 struct timespec64 get_monotonic_coarse64(void)
 {