diff --git a/sys/contrib/ncsw/user/env/core.c b/sys/contrib/ncsw/user/env/core.c
--- a/sys/contrib/ncsw/user/env/core.c
+++ b/sys/contrib/ncsw/user/env/core.c
@@ -33,7 +33,7 @@
 #include "types_ext.h"
 #include "core_ext.h"
 
-uint32_t E500_GetId()
+uint32_t E500_GetId(void)
 {
 	return PCPU_GET(cpuid);
 }
diff --git a/sys/powerpc/aim/mmu_oea.c b/sys/powerpc/aim/mmu_oea.c
--- a/sys/powerpc/aim/mmu_oea.c
+++ b/sys/powerpc/aim/mmu_oea.c
@@ -1311,7 +1311,7 @@
 }
 
 void
-moea_init()
+moea_init(void)
 {
 
 	moea_upvo_zone = uma_zcreate("UPVO entry", sizeof (struct pvo_entry),
@@ -2775,7 +2775,7 @@
 extern struct dump_pa dump_map[PHYS_AVAIL_SZ + 1];
 
 void
-moea_scan_init()
+moea_scan_init(void)
 {
 	struct pvo_entry *pvo;
 	vm_offset_t va;
diff --git a/sys/powerpc/booke/pmap.c b/sys/powerpc/booke/pmap.c
--- a/sys/powerpc/booke/pmap.c
+++ b/sys/powerpc/booke/pmap.c
@@ -1054,7 +1054,7 @@
  * system needs to map virtual memory.
  */
 static void
-mmu_booke_init()
+mmu_booke_init(void)
 {
 	int shpgperproc = PMAP_SHPGPERPROC;
 
@@ -2119,7 +2119,7 @@
 extern struct dump_pa dump_map[PHYS_AVAIL_SZ + 1];
 
 void
-mmu_booke_scan_init()
+mmu_booke_scan_init(void)
 {
 	vm_offset_t va;
 	pte_t *pte;
@@ -2822,7 +2822,7 @@
  * assembler level setup done in locore.S.
  */
 void
-tlb1_init()
+tlb1_init(void)
 {
 	vm_offset_t mas2;
 	uint32_t mas0, mas1, mas3, mas7;
diff --git a/sys/powerpc/cpufreq/mpc85xx_jog.c b/sys/powerpc/cpufreq/mpc85xx_jog.c
--- a/sys/powerpc/cpufreq/mpc85xx_jog.c
+++ b/sys/powerpc/cpufreq/mpc85xx_jog.c
@@ -121,7 +121,7 @@
 };
 
 static struct ofw_compat_data *
-mpc85xx_jog_devcompat()
+mpc85xx_jog_devcompat(void)
 {
 	phandle_t node;
 	int i;
diff --git a/sys/powerpc/powerpc/elf32_machdep.c b/sys/powerpc/powerpc/elf32_machdep.c
--- a/sys/powerpc/powerpc/elf32_machdep.c
+++ b/sys/powerpc/powerpc/elf32_machdep.c
@@ -407,7 +407,7 @@
 }
 
 static void
-ppc32_runtime_resolve()
+ppc32_runtime_resolve(void)
 {
 
 	/*