diff --git a/sys/powerpc/booke/mp_cpudep.c b/sys/powerpc/booke/mp_cpudep.c
index 709578d8e1b..b8b939a785e 100644
--- a/sys/powerpc/booke/mp_cpudep.c
+++ b/sys/powerpc/booke/mp_cpudep.c
@@ -51,7 +51,7 @@ extern void icache_inval(void);
 volatile void *ap_pcpu;
 
 uintptr_t
-cpudep_ap_bootstrap()
+cpudep_ap_bootstrap(void)
 {
 	uint32_t msr, csr;
 	uintptr_t sp;
@@ -94,6 +94,6 @@ cpudep_ap_bootstrap()
 }
 
 void
-cpudep_ap_setup()
+cpudep_ap_setup(void)
 {
 }