nsaccess.c

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

/*
 * Copyright (C) 2000 - 2012, 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 "accommon.h"
#include "amlcode.h"
#include "acnamesp.h"
#include "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 iASL compiler */

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

                obj_desc->method.info_flags =
                    ACPI_METHOD_INTERNAL_ONLY;
                obj_desc->method.dispatch.implementation =
                    acpi_ut_osi_implementation;
#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 0x%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,
                               obj_desc->common.type);

            /* 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 = prefix_node->parent;
            }
        }
    }

    /* 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 = this_node->parent;
                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 %u 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 (%u 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 (!this_node->object) {
                    return_ACPI_STATUS(AE_NOT_EXIST);
                }

                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);
}