ACPICA: Never run _REG on system_memory and system_IO

These address spaces are defined by the ACPI spec to be
"always available", and thus _REG should never be run on them.
Provides compatibility with other ACPI implementations.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpica/acevents.h

@@ -229,6 +229,8 @@ acpi_ev_default_region_setup(acpi_handle handle,
 
 acpi_status acpi_ev_initialize_region(union acpi_operand_object *region_obj);
 
+u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node);
+
 /*
  * evsci - SCI (System Control Interrupt) handling/dispatch
  */

drivers/acpi/acpica/aclocal.h

@@ -395,9 +395,9 @@ struct acpi_simple_repair_info {
 /* Info for running the _REG methods */
 
 struct acpi_reg_walk_info {
-	acpi_adr_space_type space_id;
 	u32 function;
 	u32 reg_run_count;
+	acpi_adr_space_type space_id;
 };
 
 /*****************************************************************************

drivers/acpi/acpica/evregion.c

@@ -653,6 +653,19 @@ acpi_ev_execute_reg_methods(struct acpi_namespace_node *node,
 
 	ACPI_FUNCTION_TRACE(ev_execute_reg_methods);
 
+	/*
+	 * These address spaces do not need a call to _REG, since the ACPI
+	 * specification defines them as: "must always be accessible". Since
+	 * they never change state (never become unavailable), no need to ever
+	 * call _REG on them. Also, a data_table is not a "real" address space,
+	 * so do not call _REG. September 2018.
+	 */
+	if ((space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) ||
+	    (space_id == ACPI_ADR_SPACE_SYSTEM_IO) ||
+	    (space_id == ACPI_ADR_SPACE_DATA_TABLE)) {
+		return_VOID;
+	}
+
 	info.space_id = space_id;
 	info.function = function;
 	info.reg_run_count = 0;
@@ -714,8 +727,8 @@ acpi_ev_reg_run(acpi_handle obj_handle,
 	}
 
 	/*
-	 * We only care about regions.and objects that are allowed to have address
-	 * space handlers
+	 * We only care about regions and objects that are allowed to have
+	 * address space handlers
 	 */
 	if ((node->type != ACPI_TYPE_REGION) && (node != acpi_gbl_root_node)) {
 		return (AE_OK);

drivers/acpi/acpica/evrgnini.c

@@ -16,9 +16,6 @@
 #define _COMPONENT          ACPI_EVENTS
 ACPI_MODULE_NAME("evrgnini")
 
-/* Local prototypes */
-static u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node);
-
 /*******************************************************************************
  *
  * FUNCTION:    acpi_ev_system_memory_region_setup
@@ -33,7 +30,6 @@ static u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node);
  * DESCRIPTION: Setup a system_memory operation region
  *
  ******************************************************************************/
-
 acpi_status
 acpi_ev_system_memory_region_setup(acpi_handle handle,
 				   u32 function,
@@ -313,7 +309,7 @@ acpi_ev_pci_config_region_setup(acpi_handle handle,
  *
  ******************************************************************************/
 
-static u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node)
+u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node)
 {
 	acpi_status status;
 	struct acpi_pnp_device_id *hid;

drivers/acpi/acpica/evxfregn.c

@@ -193,7 +193,6 @@ acpi_remove_address_space_handler(acpi_handle device,
 				 */
 				region_obj =
 				    handler_obj->address_space.region_list;
-
 			}
 
 			/* Remove this Handler object from the list */