drivers/acpi/namespace/nsaccess.c

/*******************************************************************************
 *
 * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
 *
 ******************************************************************************/

/*
 * Copyright (C) 2000 - 2007, R. Byron Moore
 * 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/amlcode.h>
#include <acpi/acnamesp.h>
#include <acpi/acdispat.h>

#define _COMPONENT          ACPI_NAMESPACE
ACPI_MODULE_NAME("nsaccess")

/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_root_initialize
 *
 * PARAMETERS:  None
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Allocate and initialize the default root named objects
 *
 * MUTEX:       Locks namespace for entire execution
 *
 ******************************************************************************/
acpi_status acpi_ns_root_initialize(void)
{
	acpi_status status;
	const struct acpi_predefined_names *init_val = NULL;
	struct acpi_namespace_node *new_node;
	union acpi_operand_object *obj_desc;
	acpi_string val = NULL;

	ACPI_FUNCTION_TRACE(ns_root_initialize);

	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/*
	 * The global root ptr is initially NULL, so a non-NULL value indicates
	 * that acpi_ns_root_initialize() has already been called; just return.
	 */
	if (acpi_gbl_root_node) {
		status = AE_OK;
		goto unlock_and_exit;
	}

	/*
	 * Tell the rest of the subsystem that the root is initialized
	 * (This is OK because the namespace is locked)
	 */
	acpi_gbl_root_node = &acpi_gbl_root_node_struct;

	/* Enter the pre-defined names in the name table */

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
			  "Entering predefined entries into namespace\n"));

	for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {

		/* _OSI is optional for now, will be permanent later */

		if (!ACPI_STRCMP(init_val->name, "_OSI")
		    && !acpi_gbl_create_osi_method) {
			continue;
		}

		status = acpi_ns_lookup(NULL, init_val->name, init_val->type,
					ACPI_IMODE_LOAD_PASS2,
					ACPI_NS_NO_UPSEARCH, NULL, &new_node);

		if (ACPI_FAILURE(status) || (!new_node)) {	/* Must be on same line for code converter */
			ACPI_EXCEPTION((AE_INFO, status,
					"Could not create predefined name %s",
					init_val->name));
		}

		/*
		 * Name entered successfully.
		 * If entry in pre_defined_names[] specifies an
		 * initial value, create the initial value.
		 */
		if (init_val->val) {
			status = acpi_os_predefined_override(init_val, &val);
			if (ACPI_FAILURE(status)) {
				ACPI_ERROR((AE_INFO,
					    "Could not override predefined %s",
					    init_val->name));
			}

			if (!val) {
				val = init_val->val;
			}

			/*
			 * Entry requests an initial value, allocate a
			 * descriptor for it.
			 */
			obj_desc =
			    acpi_ut_create_internal_object(init_val->type);
			if (!obj_desc) {
				status = AE_NO_MEMORY;
				goto unlock_and_exit;
			}

			/*
			 * Convert value string from table entry to
			 * internal representation. Only types actually
			 * used for initial values are implemented here.
			 */
			switch (init_val->type) {
			case ACPI_TYPE_METHOD:
				obj_desc->method.param_count =
				    (u8) ACPI_TO_INTEGER(val);
				obj_desc->common.flags |= AOPOBJ_DATA_VALID;

#if defined (ACPI_ASL_COMPILER)

				/* Save the parameter count for the i_aSL compiler */

				new_node->value = obj_desc->method.param_count;
#else
				/* Mark this as a very SPECIAL method */

				obj_desc->method.method_flags =
				    AML_METHOD_INTERNAL_ONLY;

#ifndef ACPI_DUMP_APP
				obj_desc->method.implementation =
				    acpi_ut_osi_implementation;
#endif
#endif
				break;

			case ACPI_TYPE_INTEGER:

				obj_desc->integer.value = ACPI_TO_INTEGER(val);
				break;

			case ACPI_TYPE_STRING:

				/*
				 * Build an object around the static string
				 */
				obj_desc->string.length =
				    (u32) ACPI_STRLEN(val);
				obj_desc->string.pointer = val;
				obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
				break;

			case ACPI_TYPE_MUTEX:

				obj_desc->mutex.node = new_node;
				obj_desc->mutex.sync_level =
				    (u8) (ACPI_TO_INTEGER(val) - 1);

				/* Create a mutex */

				status =
				    acpi_os_create_mutex(&obj_desc->mutex.
							 os_mutex);
				if (ACPI_FAILURE(status)) {
					acpi_ut_remove_reference(obj_desc);
					goto unlock_and_exit;
				}

				/* Special case for ACPI Global Lock */

				if (ACPI_STRCMP(init_val->name, "_GL_") == 0) {
					acpi_gbl_global_lock_mutex = obj_desc;

					/* Create additional counting semaphore for global lock */

					status =
					    acpi_os_create_semaphore(1, 0,
								     &acpi_gbl_global_lock_semaphore);
					if (ACPI_FAILURE(status)) {
						acpi_ut_remove_reference
						    (obj_desc);
						goto unlock_and_exit;
					}
				}
				break;

			default:

				ACPI_ERROR((AE_INFO,
					    "Unsupported initial type value %X",
					    init_val->type));
				acpi_ut_remove_reference(obj_desc);
				obj_desc = NULL;
				continue;
			}

			/* Store pointer to value descriptor in the Node */

			status = acpi_ns_attach_object(new_node, obj_desc,
						       ACPI_GET_OBJECT_TYPE
						       (obj_desc));

			/* Remove local reference to the object */

			acpi_ut_remove_reference(obj_desc);
		}
	}

      unlock_and_exit:
	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);

	/* Save a handle to "_GPE", it is always present */

	if (ACPI_SUCCESS(status)) {
		status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
					  &acpi_gbl_fadt_gpe_device);
	}

	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_lookup
 *
 * PARAMETERS:  scope_info      - Current scope info block
 *              Pathname        - Search pathname, in internal format
 *                                (as represented in the AML stream)
 *              Type            - Type associated with name
 *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
 *              Flags           - Flags describing the search restrictions
 *              walk_state      - Current state of the walk
 *              return_node     - Where the Node is placed (if found
 *                                or created successfully)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Find or enter the passed name in the name space.
 *              Log an error if name not found in Exec mode.
 *
 * MUTEX:       Assumes namespace is locked.
 *
 ******************************************************************************/

acpi_status
acpi_ns_lookup(union acpi_generic_state *scope_info,
	       char *pathname,
	       acpi_object_type type,
	       acpi_interpreter_mode interpreter_mode,
	       u32 flags,
	       struct acpi_walk_state *walk_state,
	       struct acpi_namespace_node **return_node)
{
	acpi_status status;
	char *path = pathname;
	struct acpi_namespace_node *prefix_node;
	struct acpi_namespace_node *current_node = NULL;
	struct acpi_namespace_node *this_node = NULL;
	u32 num_segments;
	u32 num_carats;
	acpi_name simple_name;
	acpi_object_type type_to_check_for;
	acpi_object_type this_search_type;
	u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
	u32 local_flags;

	ACPI_FUNCTION_TRACE(ns_lookup);

	if (!return_node) {
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	local_flags = flags & ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_SEARCH_PARENT);
	*return_node = ACPI_ENTRY_NOT_FOUND;
	acpi_gbl_ns_lookup_count++;

	if (!acpi_gbl_root_node) {
		return_ACPI_STATUS(AE_NO_NAMESPACE);
	}

	/*
	 * Get the prefix scope.
	 * A null scope means use the root scope
	 */
	if ((!scope_info) || (!scope_info->scope.node)) {
		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
				  "Null scope prefix, using root node (%p)\n",
				  acpi_gbl_root_node));

		prefix_node = acpi_gbl_root_node;
	} else {
		prefix_node = scope_info->scope.node;
		if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
		    ACPI_DESC_TYPE_NAMED) {
			ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
				    prefix_node,
				    acpi_ut_get_descriptor_name(prefix_node)));
			return_ACPI_STATUS(AE_AML_INTERNAL);
		}

		if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
			/*
			 * This node might not be a actual "scope" node (such as a
			 * Device/Method, etc.)  It could be a Package or other object node.
			 * Backup up the tree to find the containing scope node.
			 */
			while (!acpi_ns_opens_scope(prefix_node->type) &&
			       prefix_node->type != ACPI_TYPE_ANY) {
				prefix_node =
				    acpi_ns_get_parent_node(prefix_node);
			}
		}
	}

	/* Save type   TBD: may be no longer necessary */

	type_to_check_for = type;

	/*
	 * Begin examination of the actual pathname
	 */
	if (!pathname) {

		/* A Null name_path is allowed and refers to the root */

		num_segments = 0;
		this_node = acpi_gbl_root_node;
		path = "";

		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
				  "Null Pathname (Zero segments), Flags=%X\n",
				  flags));
	} else {
		/*
		 * Name pointer is valid (and must be in internal name format)
		 *
		 * Check for scope prefixes:
		 *
		 * As represented in the AML stream, a namepath consists of an
		 * optional scope prefix followed by a name segment part.
		 *
		 * If present, the scope prefix is either a Root Prefix (in
		 * which case the name is fully qualified), or one or more
		 * Parent Prefixes (in which case the name's scope is relative
		 * to the current scope).
		 */
		if (*path == (u8) AML_ROOT_PREFIX) {

			/* Pathname is fully qualified, start from the root */

			this_node = acpi_gbl_root_node;
			search_parent_flag = ACPI_NS_NO_UPSEARCH;

			/* Point to name segment part */

			path++;

			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
					  "Path is absolute from root [%p]\n",
					  this_node));
		} else {
			/* Pathname is relative to current scope, start there */

			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
					  "Searching relative to prefix scope [%4.4s] (%p)\n",
					  acpi_ut_get_node_name(prefix_node),
					  prefix_node));

			/*
			 * Handle multiple Parent Prefixes (carat) by just getting
			 * the parent node for each prefix instance.
			 */
			this_node = prefix_node;
			num_carats = 0;
			while (*path == (u8) AML_PARENT_PREFIX) {

				/* Name is fully qualified, no search rules apply */

				search_parent_flag = ACPI_NS_NO_UPSEARCH;
				/*
				 * Point past this prefix to the name segment
				 * part or the next Parent Prefix
				 */
				path++;

				/* Backup to the parent node */

				num_carats++;
				this_node = acpi_ns_get_parent_node(this_node);
				if (!this_node) {

					/* Current scope has no parent scope */

					ACPI_ERROR((AE_INFO,
						    "ACPI path has too many parent prefixes (^) - reached beyond root node"));
					return_ACPI_STATUS(AE_NOT_FOUND);
				}
			}

			if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
						  "Search scope is [%4.4s], path has %d carat(s)\n",
						  acpi_ut_get_node_name
						  (this_node), num_carats));
			}
		}

		/*
		 * Determine the number of ACPI name segments in this pathname.
		 *
		 * The segment part consists of either:
		 *  - A Null name segment (0)
		 *  - A dual_name_prefix followed by two 4-byte name segments
		 *  - A multi_name_prefix followed by a byte indicating the
		 *      number of segments and the segments themselves.
		 *  - A single 4-byte name segment
		 *
		 * Examine the name prefix opcode, if any, to determine the number of
		 * segments.
		 */
		switch (*path) {
		case 0:
			/*
			 * Null name after a root or parent prefixes. We already
			 * have the correct target node and there are no name segments.
			 */
			num_segments = 0;
			type = this_node->type;

			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
					  "Prefix-only Pathname (Zero name segments), Flags=%X\n",
					  flags));
			break;

		case AML_DUAL_NAME_PREFIX:

			/* More than one name_seg, search rules do not apply */

			search_parent_flag = ACPI_NS_NO_UPSEARCH;

			/* Two segments, point to first name segment */

			num_segments = 2;
			path++;

			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
					  "Dual Pathname (2 segments, Flags=%X)\n",
					  flags));
			break;

		case AML_MULTI_NAME_PREFIX_OP:

			/* More than one name_seg, search rules do not apply */

			search_parent_flag = ACPI_NS_NO_UPSEARCH;

			/* Extract segment count, point to first name segment */

			path++;
			num_segments = (u32) (u8) * path;
			path++;

			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
					  "Multi Pathname (%d Segments, Flags=%X)\n",
					  num_segments, flags));
			break;

		default:
			/*
			 * Not a Null name, no Dual or Multi prefix, hence there is
			 * only one name segment and Pathname is already pointing to it.
			 */
			num_segments = 1;

			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
					  "Simple Pathname (1 segment, Flags=%X)\n",
					  flags));
			break;
		}

		ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
	}

	/*
	 * Search namespace for each segment of the name.  Loop through and
	 * verify (or add to the namespace) each name segment.
	 *
	 * The object type is significant only at the last name
	 * segment.  (We don't care about the types along the path, only
	 * the type of the final target object.)
	 */
	this_search_type = ACPI_TYPE_ANY;
	current_node = this_node;
	while (num_segments && current_node) {
		num_segments--;
		if (!num_segments) {
			/*
			 * This is the last segment, enable typechecking
			 */
			this_search_type = type;

			/*
			 * Only allow automatic parent search (search rules) if the caller
			 * requested it AND we have a single, non-fully-qualified name_seg
			 */
			if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
			    (flags & ACPI_NS_SEARCH_PARENT)) {
				local_flags |= ACPI_NS_SEARCH_PARENT;
			}

			/* Set error flag according to caller */

			if (flags & ACPI_NS_ERROR_IF_FOUND) {
				local_flags |= ACPI_NS_ERROR_IF_FOUND;
			}
		}

		/* Extract one ACPI name from the front of the pathname */

		ACPI_MOVE_32_TO_32(&simple_name, path);

		/* Try to find the single (4 character) ACPI name */

		status =
		    acpi_ns_search_and_enter(simple_name, walk_state,
					     current_node, interpreter_mode,
					     this_search_type, local_flags,
					     &this_node);
		if (ACPI_FAILURE(status)) {
			if (status == AE_NOT_FOUND) {

				/* Name not found in ACPI namespace */

				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
						  "Name [%4.4s] not found in scope [%4.4s] %p\n",
						  (char *)&simple_name,
						  (char *)&current_node->name,
						  current_node));
			}

			*return_node = this_node;
			return_ACPI_STATUS(status);
		}

		/* More segments to follow? */

		if (num_segments > 0) {
			/*
			 * If we have an alias to an object that opens a scope (such as a
			 * device or processor), we need to dereference the alias here so that
			 * we can access any children of the original node (via the remaining
			 * segments).
			 */
			if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
				if (acpi_ns_opens_scope
				    (((struct acpi_namespace_node *)this_node->
				      object)->type)) {
					this_node =
					    (struct acpi_namespace_node *)
					    this_node->object;
				}
			}
		}

		/* Special handling for the last segment (num_segments == 0) */

		else {
			/*
			 * Sanity typecheck of the target object:
			 *
			 * If 1) This is the last segment (num_segments == 0)
			 *    2) And we are looking for a specific type
			 *       (Not checking for TYPE_ANY)
			 *    3) Which is not an alias
			 *    4) Which is not a local type (TYPE_SCOPE)
			 *    5) And the type of target object is known (not TYPE_ANY)
			 *    6) And target object does not match what we are looking for
			 *
			 * Then we have a type mismatch. Just warn and ignore it.
			 */
			if ((type_to_check_for != ACPI_TYPE_ANY) &&
			    (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
			    (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
			    && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
			    && (this_node->type != ACPI_TYPE_ANY)
			    && (this_node->type != type_to_check_for)) {

				/* Complain about a type mismatch */

				ACPI_WARNING((AE_INFO,
					      "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
					      ACPI_CAST_PTR(char, &simple_name),
					      acpi_ut_get_type_name(this_node->
								    type),
					      acpi_ut_get_type_name
					      (type_to_check_for)));
			}

			/*
			 * If this is the last name segment and we are not looking for a
			 * specific type, but the type of found object is known, use that type
			 * to (later) see if it opens a scope.
			 */
			if (type == ACPI_TYPE_ANY) {
				type = this_node->type;
			}
		}

		/* Point to next name segment and make this node current */

		path += ACPI_NAME_SIZE;
		current_node = this_node;
	}

	/*
	 * Always check if we need to open a new scope
	 */
	if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
		/*
		 * If entry is a type which opens a scope, push the new scope on the
		 * scope stack.
		 */
		if (acpi_ns_opens_scope(type)) {
			status =
			    acpi_ds_scope_stack_push(this_node, type,
						     walk_state);
			if (ACPI_FAILURE(status)) {
				return_ACPI_STATUS(status);
			}
		}
	}

	*return_node = this_node;
	return_ACPI_STATUS(AE_OK);
}