diff --git a/include/exec/ioport.h b/include/exec/ioport.h
index fc28350a3c..4953892c16 100644
--- a/include/exec/ioport.h
+++ b/include/exec/ioport.h
@@ -39,10 +39,6 @@ typedef uint32_t (IOPortReadFunc)(void *opaque, uint32_t address);
 typedef void (IOPortDestructor)(void *opaque);
 
 void ioport_register(IORange *iorange);
-int register_ioport_read(pio_addr_t start, int length, int size,
-                         IOPortReadFunc *func, void *opaque);
-int register_ioport_write(pio_addr_t start, int length, int size,
-                          IOPortWriteFunc *func, void *opaque);
 void isa_unassign_ioport(pio_addr_t start, int length);
 bool isa_is_ioport_assigned(pio_addr_t start);
 
diff --git a/ioport.c b/ioport.c
index a0ac2a0a41..d5b7fbdb5b 100644
--- a/ioport.c
+++ b/ioport.c
@@ -139,8 +139,8 @@ static int ioport_bsize(int size, int *bsize)
 }
 
 /* size is the word size in byte */
-int register_ioport_read(pio_addr_t start, int length, int size,
-                         IOPortReadFunc *func, void *opaque)
+static int register_ioport_read(pio_addr_t start, int length, int size,
+                                IOPortReadFunc *func, void *opaque)
 {
     int i, bsize;
 
@@ -159,8 +159,8 @@ int register_ioport_read(pio_addr_t start, int length, int size,
 }
 
 /* size is the word size in byte */
-int register_ioport_write(pio_addr_t start, int length, int size,
-                          IOPortWriteFunc *func, void *opaque)
+static int register_ioport_write(pio_addr_t start, int length, int size,
+                                 IOPortWriteFunc *func, void *opaque)
 {
     int i, bsize;