diff --git a/include/linux/time.h b/include/linux/time.h
index eceb1a5..8ea8dea 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -92,6 +92,7 @@
 extern struct timespec wall_to_monotonic;
 extern seqlock_t xtime_lock __attribute__((weak));
 
+extern unsigned long read_persistent_clock(void);
 void timekeeping_init(void);
 
 static inline unsigned long get_seconds(void)