diff --git a/sys/compat/linuxkpi/common/include/linux/jiffies.h b/sys/compat/linuxkpi/common/include/linux/jiffies.h
--- a/sys/compat/linuxkpi/common/include/linux/jiffies.h
+++ b/sys/compat/linuxkpi/common/include/linux/jiffies.h
@@ -39,6 +39,7 @@
 extern unsigned long jiffies;	/* defined in sys/kern/subr_ticks.S */
 #define	jiffies_64		jiffies	/* XXX-MJ wrong on 32-bit platforms */
 #define	jiffies_to_msecs(x)     ((unsigned int)(((int64_t)(int)(x)) * 1000 / hz))
+#define	jiffies64_to_msecs(x)	(((uint64_t)(x)) * 1000 / hz)
 
 #define	MAX_JIFFY_OFFSET	((LONG_MAX >> 1) - 1)