// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 /****************************************************************************** * * Module Name: nswalk - Functions for walking the ACPI namespace * * Copyright (C) 2000 - 2025, Intel Corp. * *****************************************************************************/ #include <acpi/acpi.h> #include "accommon.h" #include "acnamesp.h" #define _COMPONENT ACPI_NAMESPACE ACPI_MODULE_NAME("nswalk") /******************************************************************************* * * FUNCTION: acpi_ns_get_next_node * * PARAMETERS: parent_node - Parent node whose children we are * getting * child_node - Previous child that was found. * The NEXT child will be returned * * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if * none is found. * * DESCRIPTION: Return the next peer node within the namespace. If Handle * is valid, Scope is ignored. Otherwise, the first node * within Scope is returned. * ******************************************************************************/ struct acpi_namespace_node *acpi_ns_get_next_node(struct acpi_namespace_node *parent_node, struct acpi_namespace_node *child_node) { ACPI_FUNCTION_ENTRY(); if (!child_node) { /* It's really the parent's _scope_ that we want */ return (parent_node->child); } /* Otherwise just return the next peer */ return (child_node->peer); } /******************************************************************************* * * FUNCTION: acpi_ns_get_next_node_typed * * PARAMETERS: type - Type of node to be searched for * parent_node - Parent node whose children we are * getting * child_node - Previous child that was found. * The NEXT child will be returned * * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if * none is found. * * DESCRIPTION: Return the next peer node within the namespace. If Handle * is valid, Scope is ignored. Otherwise, the first node * within Scope is returned. * ******************************************************************************/ struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type, struct acpi_namespace_node *parent_node, struct acpi_namespace_node *child_node) { struct acpi_namespace_node *next_node = NULL; ACPI_FUNCTION_ENTRY(); next_node = acpi_ns_get_next_node(parent_node, child_node); /* If any type is OK, we are done */ if (type == ACPI_TYPE_ANY) { /* next_node is NULL if we are at the end-of-list */ return (next_node); } /* Must search for the node -- but within this scope only */ while (next_node) { /* If type matches, we are done */ if (next_node->type == type) { return (next_node); } /* Otherwise, move on to the next peer node */ next_node = next_node->peer; } /* Not found */ return (NULL); } /******************************************************************************* * * FUNCTION: acpi_ns_walk_namespace * * PARAMETERS: type - acpi_object_type to search for * start_node - Handle in namespace where search begins * max_depth - Depth to which search is to reach * flags - Whether to unlock the NS before invoking * the callback routine * descending_callback - Called during tree descent * when an object of "Type" is found * ascending_callback - Called during tree ascent * when an object of "Type" is found * context - Passed to user function(s) above * return_value - from the user_function if terminated * early. Otherwise, returns NULL. * RETURNS: Status * * DESCRIPTION: Performs a modified depth-first walk of the namespace tree, * starting (and ending) at the node specified by start_handle. * The callback function is called whenever a node that matches * the type parameter is found. If the callback function returns * a non-zero value, the search is terminated immediately and * this value is returned to the caller. * * The point of this procedure is to provide a generic namespace * walk routine that can be called from multiple places to * provide multiple services; the callback function(s) can be * tailored to each task, whether it is a print function, * a compare function, etc. * ******************************************************************************/ acpi_status acpi_ns_walk_namespace(acpi_object_type type, acpi_handle start_node, u32 max_depth, u32 flags, acpi_walk_callback descending_callback, acpi_walk_callback ascending_callback, void *context, void **return_value) { acpi_status status; acpi_status mutex_status; struct acpi_namespace_node *child_node; struct acpi_namespace_node *parent_node; acpi_object_type child_type; u32 level; u8 node_previously_visited = FALSE; ACPI_FUNCTION_TRACE(ns_walk_namespace); /* Special case for the namespace Root Node */ if (start_node == ACPI_ROOT_OBJECT) { start_node = acpi_gbl_root_node; } /* Avoid walking the namespace if the StartNode is NULL */ if (!start_node) { return_ACPI_STATUS(AE_NO_NAMESPACE); } /* Null child means "get first node" */ parent_node = start_node; child_node = acpi_ns_get_next_node(parent_node, NULL); child_type = ACPI_TYPE_ANY; level = 1; /* * Traverse the tree of nodes until we bubble back up to where we * started. When Level is zero, the loop is done because we have * bubbled up to (and passed) the original parent handle (start_entry) */ while (level > 0 && child_node) { status = AE_OK; /* Found next child, get the type if we are not searching for ANY */ if (type != ACPI_TYPE_ANY) { child_type = child_node->type; } /* * Ignore all temporary namespace nodes (created during control * method execution) unless told otherwise. These temporary nodes * can cause a race condition because they can be deleted during * the execution of the user function (if the namespace is * unlocked before invocation of the user function.) Only the * debugger namespace dump will examine the temporary nodes. */ if ((child_node->flags & ANOBJ_TEMPORARY) && !(flags & ACPI_NS_WALK_TEMP_NODES)) { status = AE_CTRL_DEPTH; } /* Type must match requested type */ else if (child_type == type) { /* * Found a matching node, invoke the user callback function. * Unlock the namespace if flag is set. */ if (flags & ACPI_NS_WALK_UNLOCK) { mutex_status = acpi_ut_release_mutex(ACPI_MTX_NAMESPACE); if (ACPI_FAILURE(mutex_status)) { return_ACPI_STATUS(mutex_status); } } /* * Invoke the user function, either descending, ascending, * or both. */ if (!node_previously_visited) { if (descending_callback) { status = descending_callback(child_node, level, context, return_value); } } else { if (ascending_callback) { status = ascending_callback(child_node, level, context, return_value); } } if (flags & ACPI_NS_WALK_UNLOCK) { mutex_status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE); if (ACPI_FAILURE(mutex_status)) { return_ACPI_STATUS(mutex_status); } } switch (status) { case AE_OK: case AE_CTRL_DEPTH: /* Just keep going */ break; case AE_CTRL_TERMINATE: /* Exit now, with OK status */ return_ACPI_STATUS(AE_OK); default: /* All others are valid exceptions */ return_ACPI_STATUS(status); } } /* * Depth first search: Attempt to go down another level in the * namespace if we are allowed to. Don't go any further if we have * reached the caller specified maximum depth or if the user * function has specified that the maximum depth has been reached. */ if (!node_previously_visited && (level < max_depth) && (status != AE_CTRL_DEPTH)) { if (child_node->child) { /* There is at least one child of this node, visit it */ level++; parent_node = child_node; child_node = acpi_ns_get_next_node(parent_node, NULL); continue; } } /* No more children, re-visit this node */ if (!node_previously_visited) { node_previously_visited = TRUE; continue; } /* No more children, visit peers */ child_node = acpi_ns_get_next_node(parent_node, child_node); if (child_node) { node_previously_visited = FALSE; } /* No peers, re-visit parent */ else { /* * No more children of this node (acpi_ns_get_next_node failed), go * back upwards in the namespace tree to the node's parent. */ level--; child_node = parent_node; parent_node = parent_node->parent; node_previously_visited = TRUE; } } /* Complete walk, not terminated by user function */ return_ACPI_STATUS(AE_OK); }
