diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index e55290df785..2656fb4d22f 100644
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -145,7 +145,8 @@ sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
 
 	getboottime(&boottime);
 
-#ifndef __mips__
+/* i386 is the only arch which uses a 32bits time_t */
+#ifdef __amd64__
 #ifdef SCTL_MASK32
 	int tv[2];