diff --git a/src/kernel/core/elf.c b/src/kernel/core/elf.c
index 8d2318e592..33aa07478c 100644
--- a/src/kernel/core/elf.c
+++ b/src/kernel/core/elf.c
@@ -25,6 +25,7 @@
 #include <elf_priv.h>
 #include <boot/elf.h>
 
+#include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>