diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index c7467f863c7a..19709a079635 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -966,7 +966,7 @@ acpi_map_iosapics (void)
 fs_initcall(acpi_map_iosapics);
 #endif				/* CONFIG_ACPI_NUMA */
 
-int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base)
+int __ref acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base)
 {
 	int err;