diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index b6e9a3786e2d..25b289ff4290 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -617,7 +617,6 @@ static int __init acpi_bus_init(void)
 {
 	int result;
 	acpi_status status;
-	extern acpi_status acpi_os_initialize1(void);
 
 	acpi_os_initialize1();
 
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 3a50a34fe176..b636b7481f31 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -23,6 +23,7 @@
 
 #define PREFIX "ACPI: "
 
+acpi_status acpi_os_initialize1(void);
 int init_acpi_device_notify(void);
 int acpi_scan_init(void);
 #ifdef	CONFIG_ACPI_PCI_SLOT
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 6ab2c3505520..605718f66642 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -52,6 +52,7 @@
 #include <acpi/acpi.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/processor.h>
+#include "internal.h"
 
 #define _COMPONENT		ACPI_OS_SERVICES
 ACPI_MODULE_NAME("osl");