LXR linux/drivers/acpi/acpica/nssearch.c

   1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2/*******************************************************************************
   3 *
   4 * Module Name: nssearch - Namespace search
   5 *
   6 ******************************************************************************/
   7
   8#include <acpi/acpi.h>
   9#include "accommon.h"
  10#include "acnamesp.h"
  11
  12#ifdef ACPI_ASL_COMPILER
  13#include "amlcode.h"
  14#endif
  15
  16#define _COMPONENT          ACPI_NAMESPACE
  17ACPI_MODULE_NAME("nssearch")
  18
  19/* Local prototypes */
  20static acpi_status
  21acpi_ns_search_parent_tree(u32 target_name,
  22                           struct acpi_namespace_node *node,
  23                           acpi_object_type type,
  24                           struct acpi_namespace_node **return_node);
  25
  26/*******************************************************************************
  27 *
  28 * FUNCTION:    acpi_ns_search_one_scope
  29 *
  30 * PARAMETERS:  target_name     - Ascii ACPI name to search for
  31 *              parent_node     - Starting node where search will begin
  32 *              type            - Object type to match
  33 *              return_node     - Where the matched Named obj is returned
  34 *
  35 * RETURN:      Status
  36 *
  37 * DESCRIPTION: Search a single level of the namespace. Performs a
  38 *              simple search of the specified level, and does not add
  39 *              entries or search parents.
  40 *
  41 *
  42 *      Named object lists are built (and subsequently dumped) in the
  43 *      order in which the names are encountered during the namespace load;
  44 *
  45 *      All namespace searching is linear in this implementation, but
  46 *      could be easily modified to support any improved search
  47 *      algorithm. However, the linear search was chosen for simplicity
  48 *      and because the trees are small and the other interpreter
  49 *      execution overhead is relatively high.
  50 *
  51 *      Note: CPU execution analysis has shown that the AML interpreter spends
  52 *      a very small percentage of its time searching the namespace. Therefore,
  53 *      the linear search seems to be sufficient, as there would seem to be
  54 *      little value in improving the search.
  55 *
  56 ******************************************************************************/
  57
  58acpi_status
  59acpi_ns_search_one_scope(u32 target_name,
  60                         struct acpi_namespace_node *parent_node,
  61                         acpi_object_type type,
  62                         struct acpi_namespace_node **return_node)
  63{
  64        struct acpi_namespace_node *node;
  65
  66        ACPI_FUNCTION_TRACE(ns_search_one_scope);
  67
  68#ifdef ACPI_DEBUG_OUTPUT
  69        if (ACPI_LV_NAMES & acpi_dbg_level) {
  70                char *scope_name;
  71
  72                scope_name = acpi_ns_get_normalized_pathname(parent_node, TRUE);
  73                if (scope_name) {
  74                        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  75                                          "Searching %s (%p) For [%4.4s] (%s)\n",
  76                                          scope_name, parent_node,
  77                                          ACPI_CAST_PTR(char, &target_name),
  78                                          acpi_ut_get_type_name(type)));
  79
  80                        ACPI_FREE(scope_name);
  81                }
  82        }
  83#endif
  84
  85        /*
  86         * Search for name at this namespace level, which is to say that we
  87         * must search for the name among the children of this object
  88         */
  89        node = parent_node->child;
  90        while (node) {
  91
  92                /* Check for match against the name */
  93
  94                if (node->name.integer == target_name) {
  95
  96                        /* Resolve a control method alias if any */
  97
  98                        if (acpi_ns_get_type(node) ==
  99                            ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 100                                node =
 101                                    ACPI_CAST_PTR(struct acpi_namespace_node,
 102                                                  node->object);
 103                        }
 104
 105                        /* Found matching entry */
 106
 107                        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 108                                          "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 109                                          ACPI_CAST_PTR(char, &target_name),
 110                                          acpi_ut_get_type_name(node->type),
 111                                          node,
 112                                          acpi_ut_get_node_name(parent_node),
 113                                          parent_node));
 114
 115                        *return_node = node;
 116                        return_ACPI_STATUS(AE_OK);
 117                }
 118
 119                /* Didn't match name, move on to the next peer object */
 120
 121                node = node->peer;
 122        }
 123
 124        /* Searched entire namespace level, not found */
 125
 126        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 127                          "Name [%4.4s] (%s) not found in search in scope [%4.4s] "
 128                          "%p first child %p\n",
 129                          ACPI_CAST_PTR(char, &target_name),
 130                          acpi_ut_get_type_name(type),
 131                          acpi_ut_get_node_name(parent_node), parent_node,
 132                          parent_node->child));
 133
 134        return_ACPI_STATUS(AE_NOT_FOUND);
 135}
 136
 137/*******************************************************************************
 138 *
 139 * FUNCTION:    acpi_ns_search_parent_tree
 140 *
 141 * PARAMETERS:  target_name     - Ascii ACPI name to search for
 142 *              node            - Starting node where search will begin
 143 *              type            - Object type to match
 144 *              return_node     - Where the matched Node is returned
 145 *
 146 * RETURN:      Status
 147 *
 148 * DESCRIPTION: Called when a name has not been found in the current namespace
 149 *              level. Before adding it or giving up, ACPI scope rules require
 150 *              searching enclosing scopes in cases identified by acpi_ns_local().
 151 *
 152 *              "A name is located by finding the matching name in the current
 153 *              name space, and then in the parent name space. If the parent
 154 *              name space does not contain the name, the search continues
 155 *              recursively until either the name is found or the name space
 156 *              does not have a parent (the root of the name space). This
 157 *              indicates that the name is not found" (From ACPI Specification,
 158 *              section 5.3)
 159 *
 160 ******************************************************************************/
 161
 162static acpi_status
 163acpi_ns_search_parent_tree(u32 target_name,
 164                           struct acpi_namespace_node *node,
 165                           acpi_object_type type,
 166                           struct acpi_namespace_node **return_node)
 167{
 168        acpi_status status;
 169        struct acpi_namespace_node *parent_node;
 170
 171        ACPI_FUNCTION_TRACE(ns_search_parent_tree);
 172
 173        parent_node = node->parent;
 174
 175        /*
 176         * If there is no parent (i.e., we are at the root) or type is "local",
 177         * we won't be searching the parent tree.
 178         */
 179        if (!parent_node) {
 180                ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 181                                  ACPI_CAST_PTR(char, &target_name)));
 182                return_ACPI_STATUS(AE_NOT_FOUND);
 183        }
 184
 185        if (acpi_ns_local(type)) {
 186                ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 187                                  "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 188                                  ACPI_CAST_PTR(char, &target_name),
 189                                  acpi_ut_get_type_name(type)));
 190                return_ACPI_STATUS(AE_NOT_FOUND);
 191        }
 192
 193        /* Search the parent tree */
 194
 195        ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 196                          "Searching parent [%4.4s] for [%4.4s]\n",
 197                          acpi_ut_get_node_name(parent_node),
 198                          ACPI_CAST_PTR(char, &target_name)));
 199
 200        /* Search parents until target is found or we have backed up to the root */
 201
 202        while (parent_node) {
 203                /*
 204                 * Search parent scope. Use TYPE_ANY because we don't care about the
 205                 * object type at this point, we only care about the existence of
 206                 * the actual name we are searching for. Typechecking comes later.
 207                 */
 208                status =
 209                    acpi_ns_search_one_scope(target_name, parent_node,
 210                                             ACPI_TYPE_ANY, return_node);
 211                if (ACPI_SUCCESS(status)) {
 212                        return_ACPI_STATUS(status);
 213                }
 214
 215                /* Not found here, go up another level (until we reach the root) */
 216
 217                parent_node = parent_node->parent;
 218        }
 219
 220        /* Not found in parent tree */
 221
 222        return_ACPI_STATUS(AE_NOT_FOUND);
 223}
 224
 225/*******************************************************************************
 226 *
 227 * FUNCTION:    acpi_ns_search_and_enter
 228 *
 229 * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 230 *              walk_state          - Current state of the walk
 231 *              node                - Starting node where search will begin
 232 *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 233 *                                    Otherwise,search only.
 234 *              type                - Object type to match
 235 *              flags               - Flags describing the search restrictions
 236 *              return_node         - Where the Node is returned
 237 *
 238 * RETURN:      Status
 239 *
 240 * DESCRIPTION: Search for a name segment in a single namespace level,
 241 *              optionally adding it if it is not found. If the passed
 242 *              Type is not Any and the type previously stored in the
 243 *              entry was Any (i.e. unknown), update the stored type.
 244 *
 245 *              In ACPI_IMODE_EXECUTE, search only.
 246 *              In other modes, search and add if not found.
 247 *
 248 ******************************************************************************/
 249
 250acpi_status
 251acpi_ns_search_and_enter(u32 target_name,
 252                         struct acpi_walk_state *walk_state,
 253                         struct acpi_namespace_node *node,
 254                         acpi_interpreter_mode interpreter_mode,
 255                         acpi_object_type type,
 256                         u32 flags, struct acpi_namespace_node **return_node)
 257{
 258        acpi_status status;
 259        struct acpi_namespace_node *new_node;
 260
 261        ACPI_FUNCTION_TRACE(ns_search_and_enter);
 262
 263        /* Parameter validation */
 264
 265        if (!node || !target_name || !return_node) {
 266                ACPI_ERROR((AE_INFO,
 267                            "Null parameter: Node %p Name 0x%X ReturnNode %p",
 268                            node, target_name, return_node));
 269                return_ACPI_STATUS(AE_BAD_PARAMETER);
 270        }
 271
 272        /*
 273         * Name must consist of valid ACPI characters. We will repair the name if
 274         * necessary because we don't want to abort because of this, but we want
 275         * all namespace names to be printable. A warning message is appropriate.
 276         *
 277         * This issue came up because there are in fact machines that exhibit
 278         * this problem, and we want to be able to enable ACPI support for them,
 279         * even though there are a few bad names.
 280         */
 281        acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
 282
 283        /* Try to find the name in the namespace level specified by the caller */
 284
 285        *return_node = ACPI_ENTRY_NOT_FOUND;
 286        status = acpi_ns_search_one_scope(target_name, node, type, return_node);
 287        if (status != AE_NOT_FOUND) {
 288                /*
 289                 * If we found it AND the request specifies that a find is an error,
 290                 * return the error
 291                 */
 292                if (status == AE_OK) {
 293
 294                        /* The node was found in the namespace */
 295
 296                        /*
 297                         * If the namespace override feature is enabled for this node,
 298                         * delete any existing attached sub-object and make the node
 299                         * look like a new node that is owned by the override table.
 300                         */
 301                        if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
 302                                ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 303                                                  "Namespace override: %4.4s pass %u type %X Owner %X\n",
 304                                                  ACPI_CAST_PTR(char,
 305                                                                &target_name),
 306                                                  interpreter_mode,
 307                                                  (*return_node)->type,
 308                                                  walk_state->owner_id));
 309
 310                                acpi_ns_delete_children(*return_node);
 311                                if (acpi_gbl_runtime_namespace_override) {
 312                                        acpi_ut_remove_reference((*return_node)->object);
 313                                        (*return_node)->object = NULL;
 314                                        (*return_node)->owner_id =
 315                                            walk_state->owner_id;
 316                                } else {
 317                                        acpi_ns_remove_node(*return_node);
 318                                        *return_node = ACPI_ENTRY_NOT_FOUND;
 319                                }
 320                        }
 321
 322                        /* Return an error if we don't expect to find the object */
 323
 324                        else if (flags & ACPI_NS_ERROR_IF_FOUND) {
 325                                status = AE_ALREADY_EXISTS;
 326                        }
 327                }
 328#ifdef ACPI_ASL_COMPILER
 329                if (*return_node && (*return_node)->type == ACPI_TYPE_ANY) {
 330                        (*return_node)->flags |= ANOBJ_IS_EXTERNAL;
 331                }
 332#endif
 333
 334                /* Either found it or there was an error: finished either way */
 335
 336                return_ACPI_STATUS(status);
 337        }
 338
 339        /*
 340         * The name was not found. If we are NOT performing the first pass
 341         * (name entry) of loading the namespace, search the parent tree (all the
 342         * way to the root if necessary.) We don't want to perform the parent
 343         * search when the namespace is actually being loaded. We want to perform
 344         * the search when namespace references are being resolved (load pass 2)
 345         * and during the execution phase.
 346         */
 347        if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 348            (flags & ACPI_NS_SEARCH_PARENT)) {
 349                /*
 350                 * Not found at this level - search parent tree according to the
 351                 * ACPI specification
 352                 */
 353                status =
 354                    acpi_ns_search_parent_tree(target_name, node, type,
 355                                               return_node);
 356                if (ACPI_SUCCESS(status)) {
 357                        return_ACPI_STATUS(status);
 358                }
 359        }
 360
 361        /* In execute mode, just search, never add names. Exit now */
 362
 363        if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 364                ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 365                                  "%4.4s Not found in %p [Not adding]\n",
 366                                  ACPI_CAST_PTR(char, &target_name), node));
 367
 368                return_ACPI_STATUS(AE_NOT_FOUND);
 369        }
 370
 371        /* Create the new named object */
 372
 373        new_node = acpi_ns_create_node(target_name);
 374        if (!new_node) {
 375                return_ACPI_STATUS(AE_NO_MEMORY);
 376        }
 377#ifdef ACPI_ASL_COMPILER
 378
 379        /* Node is an object defined by an External() statement */
 380
 381        if (flags & ACPI_NS_EXTERNAL ||
 382            (walk_state && walk_state->opcode == AML_SCOPE_OP)) {
 383                new_node->flags |= ANOBJ_IS_EXTERNAL;
 384        }
 385#endif
 386
 387        if (flags & ACPI_NS_TEMPORARY) {
 388                new_node->flags |= ANOBJ_TEMPORARY;
 389        }
 390
 391        /* Install the new object into the parent's list of children */
 392
 393        acpi_ns_install_node(walk_state, node, new_node, type);
 394        *return_node = new_node;
 395        return_ACPI_STATUS(AE_OK);
 396}
 397