1 files changed, 8 insertions, 1 deletions

diff --git a/include/linux/timex.h b/include/linux/timex.h
index 8ea3e71ba7fa..c3f374786a43 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -232,7 +232,14 @@ static inline int ntp_synced(void)
 #else
 #define NTP_INTERVAL_FREQ  (HZ)
 #endif
-#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
+
+#define CLOCK_TICK_OVERFLOW     (LATCH * HZ - CLOCK_TICK_RATE)
+#define CLOCK_TICK_ADJUST       (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / \
+                                        (s64)CLOCK_TICK_RATE)
+
+/* Because using NSEC_PER_SEC would be too easy */
+#define NTP_INTERVAL_LENGTH ((((s64)TICK_USEC * NSEC_PER_USEC * USER_HZ) + \
+                              CLOCK_TICK_ADJUST) / NTP_INTERVAL_FREQ)
 
 /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
 extern u64 current_tick_length(void);