diff --git a/sys/sys/libkern.h b/sys/sys/libkern.h
index e4a7880a46af..cab6c9741323 100644
--- a/sys/sys/libkern.h
+++ b/sys/sys/libkern.h
@@ -43,6 +43,8 @@
 #include <sys/systm.h>
 #endif
 
+#include <machine/cpufunc.h>
+
 /* BCD conversions. */
 extern u_char const	bcd2bin_data[];
 extern u_char const	bin2bcd_data[];