ACPI: scan: Make acpi_processor_add() check the device enabled bit

Modify acpi_processor_add() return an error if _STA returns the enabled
bit clear for the given processor device, so as to avoid using processors
that don't decode their resources, as per the ACPI specification. [1]

Link: https://uefi.org/specs/ACPI/6.5/06_Device_Configuration.html#sta-device-status # [1]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: rafaeljw

drivers/acpi/acpi_processor.c

@@ -381,6 +381,9 @@ static int acpi_processor_add(struct acpi_device *device,
 	struct device *dev;
 	int result = 0;
 
+	if (!acpi_device_is_enabled(device))
+		return -ENODEV;
+
 	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
 	if (!pr)
 		return -ENOMEM;

drivers/acpi/internal.h

@@ -121,6 +121,7 @@ int acpi_device_setup_files(struct acpi_device *dev);
 void acpi_device_remove_files(struct acpi_device *dev);
 void acpi_device_add_finalize(struct acpi_device *device);
 void acpi_free_pnp_ids(struct acpi_device_pnp *pnp);
+bool acpi_device_is_enabled(const struct acpi_device *adev);
 bool acpi_device_is_present(const struct acpi_device *adev);
 bool acpi_device_is_battery(struct acpi_device *adev);
 bool acpi_device_is_first_physical_node(struct acpi_device *adev,

drivers/acpi/scan.c

@@ -1945,6 +1945,11 @@ bool acpi_device_is_present(const struct acpi_device *adev)
 	return adev->status.present || adev->status.functional;
 }
 
+bool acpi_device_is_enabled(const struct acpi_device *adev)
+{
+	return adev->status.present && adev->status.enabled;
+}
+
 static bool acpi_scan_handler_matching(struct acpi_scan_handler *handler,
 				       const char *idstr,
 				       const struct acpi_device_id **matchid)