diff --git a/src/arch/x86/mpspec.c b/src/arch/x86/mpspec.c
index b8bdb09..ac3fc79 100644
--- a/src/arch/x86/mpspec.c
+++ b/src/arch/x86/mpspec.c
@@ -206,7 +206,7 @@
  * Entry Type, APIC ID, Version,
  * APIC Flags:EN, Address
  */
-void smp_write_ioapic(struct mp_config_table *mc,
+static void smp_write_ioapic(struct mp_config_table *mc,
 	u8 id, u8 ver, void *apicaddr)
 {
 	struct mpc_config_ioapic *mpc;