nssearch.c 14.2 KB
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/*******************************************************************************
 *
 * Module Name: nssearch - Namespace search
 *
 ******************************************************************************/

/*
8
 * Copyright (C) 2000 - 2017, Intel Corp.
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 * 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>
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#include "accommon.h"
#include "acnamesp.h"
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#ifdef ACPI_ASL_COMPILER
#include "amlcode.h"
#endif

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#define _COMPONENT          ACPI_NAMESPACE
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ACPI_MODULE_NAME("nssearch")
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/* Local prototypes */
static acpi_status
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acpi_ns_search_parent_tree(u32 target_name,
			   struct acpi_namespace_node *node,
			   acpi_object_type type,
			   struct acpi_namespace_node **return_node);
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/*******************************************************************************
 *
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 * FUNCTION:    acpi_ns_search_one_scope
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 *
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 * PARAMETERS:  target_name     - Ascii ACPI name to search for
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 *              parent_node     - Starting node where search will begin
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 *              type            - Object type to match
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 *              return_node     - Where the matched Named obj is returned
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 *
 * RETURN:      Status
 *
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 * DESCRIPTION: Search a single level of the namespace. Performs a
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 *              simple search of the specified level, and does not add
 *              entries or search parents.
 *
 *
 *      Named object lists are built (and subsequently dumped) in the
 *      order in which the names are encountered during the namespace load;
 *
 *      All namespace searching is linear in this implementation, but
 *      could be easily modified to support any improved search
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 *      algorithm. However, the linear search was chosen for simplicity
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 *      and because the trees are small and the other interpreter
 *      execution overhead is relatively high.
 *
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 *      Note: CPU execution analysis has shown that the AML interpreter spends
 *      a very small percentage of its time searching the namespace. Therefore,
 *      the linear search seems to be sufficient, as there would seem to be
 *      little value in improving the search.
 *
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 ******************************************************************************/

acpi_status
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acpi_ns_search_one_scope(u32 target_name,
			 struct acpi_namespace_node *parent_node,
			 acpi_object_type type,
			 struct acpi_namespace_node **return_node)
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{
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	struct acpi_namespace_node *node;
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	ACPI_FUNCTION_TRACE(ns_search_one_scope);
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#ifdef ACPI_DEBUG_OUTPUT
	if (ACPI_LV_NAMES & acpi_dbg_level) {
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		char *scope_name;
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		scope_name = acpi_ns_get_normalized_pathname(parent_node, TRUE);
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		if (scope_name) {
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			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
					  "Searching %s (%p) For [%4.4s] (%s)\n",
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					  scope_name, parent_node,
					  ACPI_CAST_PTR(char, &target_name),
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					  acpi_ut_get_type_name(type)));
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			ACPI_FREE(scope_name);
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		}
	}
#endif

	/*
	 * Search for name at this namespace level, which is to say that we
	 * must search for the name among the children of this object
	 */
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	node = parent_node->child;
	while (node) {
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		/* Check for match against the name */

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		if (node->name.integer == target_name) {
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			/* Resolve a control method alias if any */

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			if (acpi_ns_get_type(node) ==
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			    ACPI_TYPE_LOCAL_METHOD_ALIAS) {
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				node =
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				    ACPI_CAST_PTR(struct acpi_namespace_node,
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						  node->object);
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			}

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			/* Found matching entry */

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			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
					  "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
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					  ACPI_CAST_PTR(char, &target_name),
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					  acpi_ut_get_type_name(node->type),
					  node,
					  acpi_ut_get_node_name(parent_node),
					  parent_node));
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			*return_node = node;
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			return_ACPI_STATUS(AE_OK);
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		}

		/* Didn't match name, move on to the next peer object */

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		node = node->peer;
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	}

	/* Searched entire namespace level, not found */

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	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
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			  "Name [%4.4s] (%s) not found in search in scope [%4.4s] "
			  "%p first child %p\n",
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			  ACPI_CAST_PTR(char, &target_name),
			  acpi_ut_get_type_name(type),
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			  acpi_ut_get_node_name(parent_node), parent_node,
			  parent_node->child));
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	return_ACPI_STATUS(AE_NOT_FOUND);
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}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_search_parent_tree
 *
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 * PARAMETERS:  target_name     - Ascii ACPI name to search for
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 *              node            - Starting node where search will begin
 *              type            - Object type to match
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 *              return_node     - Where the matched Node is returned
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 *
 * RETURN:      Status
 *
 * DESCRIPTION: Called when a name has not been found in the current namespace
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 *              level. Before adding it or giving up, ACPI scope rules require
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 *              searching enclosing scopes in cases identified by acpi_ns_local().
 *
 *              "A name is located by finding the matching name in the current
 *              name space, and then in the parent name space. If the parent
 *              name space does not contain the name, the search continues
 *              recursively until either the name is found or the name space
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 *              does not have a parent (the root of the name space). This
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 *              indicates that the name is not found" (From ACPI Specification,
 *              section 5.3)
 *
 ******************************************************************************/

static acpi_status
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acpi_ns_search_parent_tree(u32 target_name,
			   struct acpi_namespace_node *node,
			   acpi_object_type type,
			   struct acpi_namespace_node **return_node)
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{
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	acpi_status status;
	struct acpi_namespace_node *parent_node;
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	ACPI_FUNCTION_TRACE(ns_search_parent_tree);
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	parent_node = node->parent;
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	/*
	 * If there is no parent (i.e., we are at the root) or type is "local",
	 * we won't be searching the parent tree.
	 */
	if (!parent_node) {
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		ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
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				  ACPI_CAST_PTR(char, &target_name)));
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		return_ACPI_STATUS(AE_NOT_FOUND);
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	}

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	if (acpi_ns_local(type)) {
		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
				  "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
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				  ACPI_CAST_PTR(char, &target_name),
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				  acpi_ut_get_type_name(type)));
		return_ACPI_STATUS(AE_NOT_FOUND);
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	}

	/* Search the parent tree */

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	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
			  "Searching parent [%4.4s] for [%4.4s]\n",
			  acpi_ut_get_node_name(parent_node),
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			  ACPI_CAST_PTR(char, &target_name)));
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	/* Search parents until target is found or we have backed up to the root */

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	while (parent_node) {
		/*
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		 * Search parent scope. Use TYPE_ANY because we don't care about the
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		 * object type at this point, we only care about the existence of
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		 * the actual name we are searching for. Typechecking comes later.
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		 */
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		status =
		    acpi_ns_search_one_scope(target_name, parent_node,
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					     ACPI_TYPE_ANY, return_node);
		if (ACPI_SUCCESS(status)) {
			return_ACPI_STATUS(status);
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		}

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		/* Not found here, go up another level (until we reach the root) */

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		parent_node = parent_node->parent;
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	}

	/* Not found in parent tree */

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	return_ACPI_STATUS(AE_NOT_FOUND);
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}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_search_and_enter
 *
 * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 *              walk_state          - Current state of the walk
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 *              node                - Starting node where search will begin
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 *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 *                                    Otherwise,search only.
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 *              type                - Object type to match
 *              flags               - Flags describing the search restrictions
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 *              return_node         - Where the Node is returned
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 *
 * RETURN:      Status
 *
 * DESCRIPTION: Search for a name segment in a single namespace level,
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 *              optionally adding it if it is not found. If the passed
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 *              Type is not Any and the type previously stored in the
 *              entry was Any (i.e. unknown), update the stored type.
 *
 *              In ACPI_IMODE_EXECUTE, search only.
 *              In other modes, search and add if not found.
 *
 ******************************************************************************/

acpi_status
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acpi_ns_search_and_enter(u32 target_name,
			 struct acpi_walk_state *walk_state,
			 struct acpi_namespace_node *node,
			 acpi_interpreter_mode interpreter_mode,
			 acpi_object_type type,
			 u32 flags, struct acpi_namespace_node **return_node)
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{
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	acpi_status status;
	struct acpi_namespace_node *new_node;
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	ACPI_FUNCTION_TRACE(ns_search_and_enter);
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	/* Parameter validation */

	if (!node || !target_name || !return_node) {
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		ACPI_ERROR((AE_INFO,
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			    "Null parameter: Node %p Name 0x%X ReturnNode %p",
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			    node, target_name, return_node));
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		return_ACPI_STATUS(AE_BAD_PARAMETER);
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	}

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	/*
	 * Name must consist of valid ACPI characters. We will repair the name if
	 * necessary because we don't want to abort because of this, but we want
	 * all namespace names to be printable. A warning message is appropriate.
	 *
	 * This issue came up because there are in fact machines that exhibit
	 * this problem, and we want to be able to enable ACPI support for them,
	 * even though there are a few bad names.
	 */
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	acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
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	/* Try to find the name in the namespace level specified by the caller */

	*return_node = ACPI_ENTRY_NOT_FOUND;
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	status = acpi_ns_search_one_scope(target_name, node, type, return_node);
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	if (status != AE_NOT_FOUND) {
		/*
		 * If we found it AND the request specifies that a find is an error,
		 * return the error
		 */
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		if (status == AE_OK) {

			/* The node was found in the namespace */

			/*
			 * If the namespace override feature is enabled for this node,
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			 * delete any existing attached sub-object and make the node
			 * look like a new node that is owned by the override table.
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			 */
			if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
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				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
						  "Namespace override: %4.4s pass %u type %X Owner %X\n",
						  ACPI_CAST_PTR(char,
								&target_name),
						  interpreter_mode,
						  (*return_node)->type,
						  walk_state->owner_id));

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				acpi_ns_delete_children(*return_node);
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				if (acpi_gbl_runtime_namespace_override) {
					acpi_ut_remove_reference((*return_node)->object);
					(*return_node)->object = NULL;
					(*return_node)->owner_id =
					    walk_state->owner_id;
				} else {
					acpi_ns_remove_node(*return_node);
					*return_node = ACPI_ENTRY_NOT_FOUND;
				}
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			}

			/* Return an error if we don't expect to find the object */

			else if (flags & ACPI_NS_ERROR_IF_FOUND) {
				status = AE_ALREADY_EXISTS;
			}
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		}
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#ifdef ACPI_ASL_COMPILER
		if (*return_node && (*return_node)->type == ACPI_TYPE_ANY) {
			(*return_node)->flags |= ANOBJ_IS_EXTERNAL;
		}
#endif
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		/* Either found it or there was an error: finished either way */

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		return_ACPI_STATUS(status);
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	}

	/*
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	 * The name was not found. If we are NOT performing the first pass
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	 * (name entry) of loading the namespace, search the parent tree (all the
	 * way to the root if necessary.) We don't want to perform the parent
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	 * search when the namespace is actually being loaded. We want to perform
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	 * the search when namespace references are being resolved (load pass 2)
	 * and during the execution phase.
	 */
	if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
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	    (flags & ACPI_NS_SEARCH_PARENT)) {
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		/*
		 * Not found at this level - search parent tree according to the
		 * ACPI specification
		 */
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		status =
		    acpi_ns_search_parent_tree(target_name, node, type,
					       return_node);
		if (ACPI_SUCCESS(status)) {
			return_ACPI_STATUS(status);
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		}
	}

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	/* In execute mode, just search, never add names. Exit now */

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	if (interpreter_mode == ACPI_IMODE_EXECUTE) {
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		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
				  "%4.4s Not found in %p [Not adding]\n",
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				  ACPI_CAST_PTR(char, &target_name), node));
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		return_ACPI_STATUS(AE_NOT_FOUND);
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	}

	/* Create the new named object */

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	new_node = acpi_ns_create_node(target_name);
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	if (!new_node) {
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		return_ACPI_STATUS(AE_NO_MEMORY);
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	}
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#ifdef ACPI_ASL_COMPILER
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	/* Node is an object defined by an External() statement */

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	if (flags & ACPI_NS_EXTERNAL ||
	    (walk_state && walk_state->opcode == AML_SCOPE_OP)) {
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		new_node->flags |= ANOBJ_IS_EXTERNAL;
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		new_node->flags |= IMPLICIT_EXTERNAL;
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	}
#endif
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	if (flags & ACPI_NS_TEMPORARY) {
		new_node->flags |= ANOBJ_TEMPORARY;
	}

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	/* Install the new object into the parent's list of children */

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	acpi_ns_install_node(walk_state, node, new_node, type);
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	*return_node = new_node;
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	return_ACPI_STATUS(AE_OK);
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}