ACPICA: Add support to externally execute _OSI method

The current implemenation of _OSI within ACPICA only allows other
control methods to execute _OSI. This change allows the host
OS to execute _OSI via the AcpiEvaluateObject interface. _OSI
is a special method -- it does not exist in the AML code, it is
implemented within ACPICA.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/parser/psxface.c b/drivers/acpi/parser/psxface.c
index 270469a..4985ce5 100644
--- a/drivers/acpi/parser/psxface.c
+++ b/drivers/acpi/parser/psxface.c
@@ -45,6 +45,7 @@
 #include <acpi/acparser.h>
 #include <acpi/acdispat.h>
 #include <acpi/acinterp.h>
+#include <acpi/amlcode.h>
 
 #define _COMPONENT          ACPI_PARSER
 ACPI_MODULE_NAME("psxface")
@@ -278,6 +279,22 @@
 		goto cleanup;
 	}
 
+	/* Invoke an internal method if necessary */
+
+	if (info->obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY) {
+		status = info->obj_desc->method.implementation(walk_state);
+		info->return_object = walk_state->return_desc;
+
+		/* Cleanup states */
+
+		acpi_ds_scope_stack_clear(walk_state);
+		acpi_ps_cleanup_scope(&walk_state->parser_state);
+		acpi_ds_terminate_control_method(walk_state->method_desc,
+						 walk_state);
+		acpi_ds_delete_walk_state(walk_state);
+		goto cleanup;
+	}
+
 	/* Parse the AML */
 
 	status = acpi_ps_parse_aml(walk_state);