diff -drupN a/include/linux/timekeeping.h b/include/linux/timekeeping.h
--- a/include/linux/timekeeping.h	2018-08-06 17:23:04.000000000 +0300
+++ b/include/linux/timekeeping.h	2022-06-12 05:28:14.000000000 +0300
@@ -249,6 +249,7 @@ static inline u64 ktime_get_raw_ns(void)
 
 extern u64 ktime_get_mono_fast_ns(void);
 extern u64 ktime_get_raw_fast_ns(void);
+extern u64 ktime_get_boot_fast_ns(void);
 
 /*
  * Timespec interfaces utilizing the ktime based ones