ACPICA: New: Validation for predefined ACPI methods/objects

Validates predefined ACPI objects that appear in the namespace,
at the time they are evaluated. The argument count and the type of
the returned object are validated. The purpose of this validation
is to detect problems with the BIOS-exposed predefined ACPI objects
before the results are returned to the ACPI-related drivers.

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>

1 files changed, 900 insertions, 0 deletions

diff --git a/drivers/acpi/namespace/nspredef.c b/drivers/acpi/namespace/nspredef.c
new file mode 100644
index 00000000000..0f17cf0898c
--- /dev/null
+++ b/drivers/acpi/namespace/nspredef.c
@@ -0,0 +1,900 @@
+/******************************************************************************
+ *
+ * Module Name: nspredef - Validation of ACPI predefined methods and objects
+ *              $Revision: 1.1 $
+ *
+ *****************************************************************************/
+
+/*
+ * Copyright (C) 2000 - 2008, Intel Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce at minimum a disclaimer
+ *    substantially similar to the "NO WARRANTY" disclaimer below
+ *    ("Disclaimer") and any redistribution must be conditioned upon
+ *    including a substantially similar Disclaimer requirement for further
+ *    binary redistribution.
+ * 3. Neither the names of the above-listed copyright holders nor the names
+ *    of any contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * NO WARRANTY
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGES.
+ */
+
+#include <acpi/acpi.h>
+#include <acpi/acnamesp.h>
+#include <acpi/acpredef.h>
+
+#define _COMPONENT          ACPI_NAMESPACE
+ACPI_MODULE_NAME("nspredef")
+
+/*******************************************************************************
+ *
+ * This module validates predefined ACPI objects that appear in the namespace,
+ * at the time they are evaluated (via acpi_evaluate_object). The purpose of this
+ * validation is to detect problems with BIOS-exposed predefined ACPI objects
+ * before the results are returned to the ACPI-related drivers.
+ *
+ * There are several areas that are validated:
+ *
+ *  1) The number of input arguments as defined by the method/object in the
+ *      ASL is validated against the ACPI specification.
+ *  2) The type of the return object (if any) is validated against the ACPI
+ *      specification.
+ *  3) For returned package objects, the count of package elements is
+ *      validated, as well as the type of each package element. Nested
+ *      packages are supported.
+ *
+ * For any problems found, a warning message is issued.
+ *
+ ******************************************************************************/
+/* Local prototypes */
+static acpi_status
+acpi_ns_check_package(char *pathname,
+		      union acpi_operand_object *return_object,
+		      const union acpi_predefined_info *predefined);
+
+static acpi_status
+acpi_ns_check_package_elements(char *pathname,
+			       union acpi_operand_object **elements,
+			       u8 type1, u32 count1, u8 type2, u32 count2);
+
+static acpi_status
+acpi_ns_check_object_type(char *pathname,
+			  union acpi_operand_object *return_object,
+			  u32 expected_btypes, u32 package_index);
+
+static acpi_status
+acpi_ns_check_reference(char *pathname,
+			union acpi_operand_object *return_object);
+
+/*
+ * Names for the types that can be returned by the predefined objects.
+ * Used for warning messages. Must be in the same order as the ACPI_RTYPEs
+ */
+static const char *acpi_rtype_names[] = {
+	"/Integer",
+	"/String",
+	"/Buffer",
+	"/Package",
+	"/Reference",
+};
+
+#define ACPI_NOT_PACKAGE    ACPI_UINT32_MAX
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_check_predefined_names
+ *
+ * PARAMETERS:  Node            - Namespace node for the method/object
+ *              return_object   - Object returned from the evaluation of this
+ *                                method/object
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Check an ACPI name for a match in the predefined name list.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ns_check_predefined_names(struct acpi_namespace_node *node,
+			       union acpi_operand_object *return_object)
+{
+	acpi_status status = AE_OK;
+	const union acpi_predefined_info *predefined;
+	char *pathname;
+
+	/* Match the name for this method/object against the predefined list */
+
+	predefined = acpi_ns_check_for_predefined_name(node);
+	if (!predefined) {
+
+		/* Name was not one of the predefined names */
+
+		return (AE_OK);
+	}
+
+	/* Get the full pathname to the object, for use in error messages */
+
+	pathname = acpi_ns_get_external_pathname(node);
+	if (!pathname) {
+		pathname = ACPI_CAST_PTR(char, predefined->info.name);
+	}
+
+	/*
+	 * Check that the parameter count for this method is in accordance
+	 * with the ACPI specification.
+	 */
+	acpi_ns_check_parameter_count(pathname, node, predefined);
+
+	/*
+	 * If there is no return value, check if we require a return value for
+	 * this predefined name. Either one return value is expected, or none,
+	 * for both methods and other objects.
+	 *
+	 * Exit now if there is no return object. Warning if one was expected.
+	 */
+	if (!return_object) {
+		if ((predefined->info.expected_btypes) &&
+		    (!(predefined->info.expected_btypes & ACPI_RTYPE_NONE))) {
+			ACPI_ERROR((AE_INFO,
+				    "%s: Missing expected return value",
+				    pathname));
+
+			status = AE_AML_NO_RETURN_VALUE;
+		}
+		goto exit;
+	}
+
+	/*
+	 * We have a return value, but if one wasn't expected, just exit, this is
+	 * not a problem
+	 *
+	 * For example, if "Implicit return value" is enabled, methods will
+	 * always return a value
+	 */
+	if (!predefined->info.expected_btypes) {
+		goto exit;
+	}
+
+	/*
+	 * Check that the type of the return object is what is expected for
+	 * this predefined name
+	 */
+	status = acpi_ns_check_object_type(pathname, return_object,
+					   predefined->info.expected_btypes,
+					   ACPI_NOT_PACKAGE);
+	if (ACPI_FAILURE(status)) {
+		goto exit;
+	}
+
+	/* For returned Package objects, check the type of all sub-objects */
+
+	if (ACPI_GET_OBJECT_TYPE(return_object) == ACPI_TYPE_PACKAGE) {
+		status =
+		    acpi_ns_check_package(pathname, return_object, predefined);
+	}
+
+      exit:
+	if (pathname) {
+		ACPI_FREE(pathname);
+	}
+
+	return (status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_check_parameter_count
+ *
+ * PARAMETERS:  Pathname        - Full pathname to the node (for error msgs)
+ *              Node            - Namespace node for the method/object
+ *              Predefined      - Pointer to entry in predefined name table
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Check that the declared (in ASL/AML) parameter count for a
+ *              predefined name is what is expected (i.e., what is defined in
+ *              the ACPI specification for this predefined name.)
+ *
+ ******************************************************************************/
+
+void
+acpi_ns_check_parameter_count(char *pathname,
+			      struct acpi_namespace_node *node,
+			      const union acpi_predefined_info *predefined)
+{
+	u32 param_count;
+	u32 required_params_current;
+	u32 required_params_old;
+
+	/*
+	 * Check that the ASL-defined parameter count is what is expected for
+	 * this predefined name.
+	 *
+	 * Methods have 0-7 parameters. All other types have zero.
+	 */
+	param_count = 0;
+	if (node->type == ACPI_TYPE_METHOD) {
+		param_count = node->object->method.param_count;
+	}
+
+	/* Validate parameter count - allow two different legal counts (_SCP) */
+
+	required_params_current = predefined->info.param_count & 0x0F;
+	required_params_old = predefined->info.param_count >> 4;
+
+	if ((param_count != required_params_current) &&
+	    (param_count != required_params_old)) {
+		ACPI_WARNING((AE_INFO,
+			      "%s: Parameter count mismatch - ASL declared %d, expected %d",
+			      pathname, param_count, required_params_current));
+	}
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_check_for_predefined_name
+ *
+ * PARAMETERS:  Node            - Namespace node for the method/object
+ *
+ * RETURN:      Pointer to entry in predefined table. NULL indicates not found.
+ *
+ * DESCRIPTION: Check an object name against the predefined object list.
+ *
+ ******************************************************************************/
+
+const union acpi_predefined_info *acpi_ns_check_for_predefined_name(struct
+								    acpi_namespace_node
+								    *node)
+{
+	const union acpi_predefined_info *this_name;
+
+	/* Quick check for a predefined name, first character must be underscore */
+
+	if (node->name.ascii[0] != '_') {
+		return (NULL);
+	}
+
+	/* Search info table for a predefined method/object name */
+
+	this_name = predefined_names;
+	while (this_name->info.name[0]) {
+		if (ACPI_COMPARE_NAME(node->name.ascii, this_name->info.name)) {
+
+			/* Return pointer to this table entry */
+
+			return (this_name);
+		}
+
+		/*
+		 * Skip next entry in the table if this name returns a Package
+		 * (next entry contains the package info)
+		 */
+		if (this_name->info.expected_btypes & ACPI_RTYPE_PACKAGE) {
+			this_name++;
+		}
+
+		this_name++;
+	}
+
+	return (NULL);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_check_package
+ *
+ * PARAMETERS:  Pathname        - Full pathname to the node (for error msgs)
+ *              return_object   - Object returned from the evaluation of a
+ *                                method or object
+ *              Predefined      - Pointer to entry in predefined name table
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Check a returned package object for the correct count and
+ *              correct type of all sub-objects.
+ *
+ ******************************************************************************/
+
+static acpi_status
+acpi_ns_check_package(char *pathname,
+		      union acpi_operand_object *return_object,
+		      const union acpi_predefined_info *predefined)
+{
+	const union acpi_predefined_info *package;
+	union acpi_operand_object *sub_package;
+	union acpi_operand_object **elements;
+	union acpi_operand_object **sub_elements;
+	acpi_status status;
+	u32 expected_count;
+	u32 count;
+	u32 i;
+	u32 j;
+
+	ACPI_FUNCTION_NAME(ns_check_package);
+
+	/* The package info for this name is in the next table entry */
+
+	package = predefined + 1;
+
+	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
+			  "%s Validating return Package of Type %X, Count %X\n",
+			  pathname, package->ret_info.type,
+			  return_object->package.count));
+
+	/* Extract package count and elements array */
+
+	elements = return_object->package.elements;
+	count = return_object->package.count;
+
+	/* The package must have at least one element, else invalid */
+
+	if (!count) {
+		ACPI_WARNING((AE_INFO,
+			      "%s: Return Package has no elements (empty)",
+			      pathname));
+
+		return (AE_AML_OPERAND_VALUE);
+	}
+
+	/*
+	 * Decode the type of the expected package contents
+	 *
+	 * PTYPE1 packages contain no subpackages
+	 * PTYPE2 packages contain sub-packages
+	 */
+	switch (package->ret_info.type) {
+	case ACPI_PTYPE1_FIXED:
+
+		/*
+		 * The package count is fixed and there are no sub-packages
+		 *
+		 * If package is too small, exit.
+		 * If package is larger than expected, issue warning but continue
+		 */
+		expected_count =
+		    package->ret_info.count1 + package->ret_info.count2;
+		if (count < expected_count) {
+			goto package_too_small;
+		} else if (count > expected_count) {
+			ACPI_WARNING((AE_INFO,
+				      "%s: Return Package is larger than needed - "
+				      "found %u, expected %u", pathname, count,
+				      expected_count));
+		}
+
+		/* Validate all elements of the returned package */
+
+		status = acpi_ns_check_package_elements(pathname, elements,
+							package->ret_info.
+							object_type1,
+							package->ret_info.
+							count1,
+							package->ret_info.
+							object_type2,
+							package->ret_info.
+							count2);
+		if (ACPI_FAILURE(status)) {
+			return (status);
+		}
+		break;
+
+	case ACPI_PTYPE1_VAR:
+
+		/*
+		 * The package count is variable, there are no sub-packages, and all
+		 * elements must be of the same type
+		 */
+		for (i = 0; i < count; i++) {
+			status = acpi_ns_check_object_type(pathname, *elements,
+							   package->ret_info.
+							   object_type1, i);
+			if (ACPI_FAILURE(status)) {
+				return (status);
+			}
+			elements++;
+		}
+		break;
+
+	case ACPI_PTYPE1_OPTION:
+
+		/*
+		 * The package count is variable, there are no sub-packages. There are
+		 * a fixed number of required elements, and a variable number of
+		 * optional elements.
+		 *
+		 * Check if package is at least as large as the minimum required
+		 */
+		expected_count = package->ret_info3.count;
+		if (count < expected_count) {
+			goto package_too_small;
+		}
+
+		/* Variable number of sub-objects */
+
+		for (i = 0; i < count; i++) {
+			if (i < package->ret_info3.count) {
+
+				/* These are the required package elements (0, 1, or 2) */
+
+				status =
+				    acpi_ns_check_object_type(pathname,
+							      *elements,
+							      package->
+							      ret_info3.
+							      object_type[i],
+							      i);
+				if (ACPI_FAILURE(status)) {
+					return (status);
+				}
+			} else {
+				/* These are the optional package elements */
+
+				status =
+				    acpi_ns_check_object_type(pathname,
+							      *elements,
+							      package->
+							      ret_info3.
+							      tail_object_type,
+							      i);
+				if (ACPI_FAILURE(status)) {
+					return (status);
+				}
+			}
+			elements++;
+		}
+		break;
+
+	case ACPI_PTYPE2_PKG_COUNT:
+
+		/* First element is the (Integer) count of sub-packages to follow */
+
+		status = acpi_ns_check_object_type(pathname, *elements,
+						   ACPI_RTYPE_INTEGER, 0);
+		if (ACPI_FAILURE(status)) {
+			return (status);
+		}
+
+		/*
+		 * Count cannot be larger than the parent package length, but allow it
+		 * to be smaller. The >= accounts for the Integer above.
+		 */
+		expected_count = (u32) (*elements)->integer.value;
+		if (expected_count >= count) {
+			goto package_too_small;
+		}
+
+		count = expected_count;
+		elements++;
+
+		/* Now we can walk the sub-packages */
+
+		/*lint -fallthrough */
+
+	case ACPI_PTYPE2:
+	case ACPI_PTYPE2_FIXED:
+	case ACPI_PTYPE2_MIN:
+	case ACPI_PTYPE2_COUNT:
+
+		/*
+		 * These types all return a single package that consists of a variable
+		 * number of sub-packages
+		 */
+		for (i = 0; i < count; i++) {
+			sub_package = *elements;
+			sub_elements = sub_package->package.elements;
+
+			/* Each sub-object must be of type Package */
+
+			status =
+			    acpi_ns_check_object_type(pathname, sub_package,
+						      ACPI_RTYPE_PACKAGE, i);
+			if (ACPI_FAILURE(status)) {
+				return (status);
+			}
+
+			/* Examine the different types of sub-packages */
+
+			switch (package->ret_info.type) {
+			case ACPI_PTYPE2:
+			case ACPI_PTYPE2_PKG_COUNT:
+
+				/* Each subpackage has a fixed number of elements */
+
+				expected_count =
+				    package->ret_info.count1 +
+				    package->ret_info.count2;
+				if (sub_package->package.count !=
+				    expected_count) {
+					count = sub_package->package.count;
+					goto package_too_small;
+				}
+
+				status =
+				    acpi_ns_check_package_elements(pathname,
+								   sub_elements,
+								   package->
+								   ret_info.
+								   object_type1,
+								   package->
+								   ret_info.
+								   count1,
+								   package->
+								   ret_info.
+								   object_type2,
+								   package->
+								   ret_info.
+								   count2);
+				if (ACPI_FAILURE(status)) {
+					return (status);
+				}
+				break;
+
+			case ACPI_PTYPE2_FIXED:
+
+				/* Each sub-package has a fixed length */
+
+				expected_count = package->ret_info2.count;
+				if (sub_package->package.count < expected_count) {
+					count = sub_package->package.count;
+					goto package_too_small;
+				}
+
+				/* Check the type of each sub-package element */
+
+				for (j = 0; j < expected_count; j++) {
+					status =
+					    acpi_ns_check_object_type(pathname,
+								      sub_elements
+								      [j],
+								      package->
+								      ret_info2.
+								      object_type
+								      [j], j);
+					if (ACPI_FAILURE(status)) {
+						return (status);
+					}
+				}
+				break;
+
+			case ACPI_PTYPE2_MIN:
+
+				/* Each sub-package has a variable but minimum length */
+
+				expected_count = package->ret_info.count1;
+				if (sub_package->package.count < expected_count) {
+					count = sub_package->package.count;
+					goto package_too_small;
+				}
+
+				/* Check the type of each sub-package element */
+
+				status =
+				    acpi_ns_check_package_elements(pathname,
+								   sub_elements,
+								   package->
+								   ret_info.
+								   object_type1,
+								   sub_package->
+								   package.
+								   count, 0, 0);
+				if (ACPI_FAILURE(status)) {
+					return (status);
+				}
+				break;
+
+			case ACPI_PTYPE2_COUNT:
+
+				/* First element is the (Integer) count of elements to follow */
+
+				status =
+				    acpi_ns_check_object_type(pathname,
+							      *sub_elements,
+							      ACPI_RTYPE_INTEGER,
+							      0);
+				if (ACPI_FAILURE(status)) {
+					return (status);
+				}
+
+				/* Make sure package is large enough for the Count */
+
+				expected_count =
+				    (u32) (*sub_elements)->integer.value;
+				if (sub_package->package.count < expected_count) {
+					count = sub_package->package.count;
+					goto package_too_small;
+				}
+
+				/* Check the type of each sub-package element */
+
+				status =
+				    acpi_ns_check_package_elements(pathname,
+								   (sub_elements
+								    + 1),
+								   package->
+								   ret_info.
+								   object_type1,
+								   (expected_count
+								    - 1), 0, 0);
+				if (ACPI_FAILURE(status)) {
+					return (status);
+				}
+				break;
+
+			default:
+				break;
+			}
+
+			elements++;
+		}
+		break;
+
+	default:
+
+		/* Should not get here if predefined info table is correct */
+
+		ACPI_WARNING((AE_INFO,
+			      "%s: Invalid internal return type in table entry: %X",
+			      pathname, package->ret_info.type));
+
+		return (AE_AML_INTERNAL);
+	}
+
+	return (AE_OK);
+
+      package_too_small:
+
+	/* Error exit for the case with an incorrect package count */
+
+	ACPI_WARNING((AE_INFO, "%s: Return Package is too small - "
+		      "found %u, expected %u", pathname, count,
+		      expected_count));
+
+	return (AE_AML_OPERAND_VALUE);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_check_package_elements
+ *
+ * PARAMETERS:  Pathname        - Full pathname to the node (for error msgs)
+ *              Elements        - Pointer to the package elements array
+ *              Type1           - Object type for first group
+ *              Count1          - Count for first group
+ *              Type2           - Object type for second group
+ *              Count2          - Count for second group
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Check that all elements of a package are of the correct object
+ *              type. Supports up to two groups of different object types.
+ *
+ ******************************************************************************/
+
+static acpi_status
+acpi_ns_check_package_elements(char *pathname,
+			       union acpi_operand_object **elements,
+			       u8 type1, u32 count1, u8 type2, u32 count2)
+{
+	union acpi_operand_object **this_element = elements;
+	acpi_status status;
+	u32 i;
+
+	/*
+	 * Up to two groups of package elements are supported by the data
+	 * structure. All elements in each group must be of the same type.
+	 * The second group can have a count of zero.
+	 */
+	for (i = 0; i < count1; i++) {
+		status = acpi_ns_check_object_type(pathname, *this_element,
+						   type1, i);
+		if (ACPI_FAILURE(status)) {
+			return (status);
+		}
+		this_element++;
+	}
+
+	for (i = 0; i < count2; i++) {
+		status = acpi_ns_check_object_type(pathname, *this_element,
+						   type2, (i + count1));
+		if (ACPI_FAILURE(status)) {
+			return (status);
+		}
+		this_element++;
+	}
+
+	return (AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_check_object_type
+ *
+ * PARAMETERS:  Pathname        - Full pathname to the node (for error msgs)
+ *              return_object   - Object return from the execution of this
+ *                                method/object
+ *              expected_btypes - Bitmap of expected return type(s)
+ *              package_index   - Index of object within parent package (if
+ *                                applicable - ACPI_NOT_PACKAGE otherwise)
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Check the type of the return object against the expected object
+ *              type(s). Use of Btype allows multiple expected object types.
+ *
+ ******************************************************************************/
+
+static acpi_status
+acpi_ns_check_object_type(char *pathname,
+			  union acpi_operand_object *return_object,
+			  u32 expected_btypes, u32 package_index)
+{
+	acpi_status status = AE_OK;
+	u32 return_btype;
+	char type_buffer[48];	/* Room for 5 types */
+	u32 this_rtype;
+	u32 i;
+	u32 j;
+
+	/*
+	 * If we get a NULL return_object here, it is a NULL package element,
+	 * and this is always an error.
+	 */
+	if (!return_object) {
+		goto type_error_exit;
+	}
+
+	/* A Namespace node should not get here, but make sure */
+
+	if (ACPI_GET_DESCRIPTOR_TYPE(return_object) == ACPI_DESC_TYPE_NAMED) {
+		ACPI_WARNING((AE_INFO,
+			      "%s: Invalid return type - Found a Namespace node [%4.4s] type %s",
+			      pathname, return_object->node.name.ascii,
+			      acpi_ut_get_type_name(return_object->node.type)));
+		return (AE_AML_OPERAND_TYPE);
+	}
+
+	/*
+	 * Convert the object type (ACPI_TYPE_xxx) to a bitmapped object type.
+	 * The bitmapped type allows multiple possible return types.
+	 *
+	 * Note, the cases below must handle all of the possible types returned
+	 * from all of the predefined names (including elements of returned
+	 * packages)
+	 */
+	switch (ACPI_GET_OBJECT_TYPE(return_object)) {
+	case ACPI_TYPE_INTEGER:
+		return_btype = ACPI_RTYPE_INTEGER;
+		break;
+
+	case ACPI_TYPE_BUFFER:
+		return_btype = ACPI_RTYPE_BUFFER;
+		break;
+
+	case ACPI_TYPE_STRING:
+		return_btype = ACPI_RTYPE_STRING;
+		break;
+
+	case ACPI_TYPE_PACKAGE:
+		return_btype = ACPI_RTYPE_PACKAGE;
+		break;
+
+	case ACPI_TYPE_LOCAL_REFERENCE:
+		return_btype = ACPI_RTYPE_REFERENCE;
+		break;
+
+	default:
+		/* Not one of the supported objects, must be incorrect */
+
+		goto type_error_exit;
+	}
+
+	/* Is the object one of the expected types? */
+
+	if (!(return_btype & expected_btypes)) {
+		goto type_error_exit;
+	}
+
+	/* For reference objects, check that the reference type is correct */
+
+	if (ACPI_GET_OBJECT_TYPE(return_object) == ACPI_TYPE_LOCAL_REFERENCE) {
+		status = acpi_ns_check_reference(pathname, return_object);
+	}
+
+	return (status);
+
+      type_error_exit:
+
+	/* Create a string with all expected types for this predefined object */
+
+	j = 1;
+	type_buffer[0] = 0;
+	this_rtype = ACPI_RTYPE_INTEGER;
+
+	for (i = 0; i < ACPI_NUM_RTYPES; i++) {
+
+		/* If one of the expected types, concatenate the name of this type */
+
+		if (expected_btypes & this_rtype) {
+			ACPI_STRCAT(type_buffer, &acpi_rtype_names[i][j]);
+			j = 0;	/* Use name separator from now on */
+		}
+		this_rtype <<= 1;	/* Next Rtype */
+	}
+
+	if (package_index == ACPI_NOT_PACKAGE) {
+		ACPI_WARNING((AE_INFO,
+			      "%s: Return type mismatch - found %s, expected %s",
+			      pathname,
+			      acpi_ut_get_object_type_name(return_object),
+			      type_buffer));
+	} else {
+		ACPI_WARNING((AE_INFO,
+			      "%s: Return Package type mismatch at index %u - "
+			      "found %s, expected %s", pathname, package_index,
+			      acpi_ut_get_object_type_name(return_object),
+			      type_buffer));
+	}
+
+	return (AE_AML_OPERAND_TYPE);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_check_reference
+ *
+ * PARAMETERS:  Pathname        - Full pathname to the node (for error msgs)
+ *              return_object   - Object returned from the evaluation of a
+ *                                method or object
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Check a returned reference object for the correct reference
+ *              type. The only reference type that can be returned from a
+ *              predefined method is a named reference. All others are invalid.
+ *
+ ******************************************************************************/
+
+static acpi_status
+acpi_ns_check_reference(char *pathname,
+			union acpi_operand_object *return_object)
+{
+
+	/*
+	 * Check the reference object for the correct reference type (opcode).
+	 * The only type of reference that can be converted to an union acpi_object is
+	 * a reference to a named object (reference class: NAME)
+	 */
+	if (return_object->reference.class == ACPI_REFCLASS_NAME) {
+		return (AE_OK);
+	}
+
+	ACPI_WARNING((AE_INFO,
+		      "%s: Return type mismatch - unexpected reference object type [%s] %2.2X",
+		      pathname, acpi_ut_get_reference_name(return_object),
+		      return_object->reference.class));
+
+	return (AE_AML_OPERAND_TYPE);
+}