drivers/acpi/acpica/nsaccess.c

   1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2 /*******************************************************************************
   3  *
   4  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
   5  *
   6  ******************************************************************************/
   7
   8 #include <acpi/acpi.h>
   9 #include "accommon.h"
  10 #include "amlcode.h"
  11 #include "acnamesp.h"
  12 #include "acdispat.h"
  13
  14 #ifdef ACPI_ASL_COMPILER
  15 #include "acdisasm.h"
  16 #endif
  17
  18 #define _COMPONENT          ACPI_NAMESPACE
  19 ACPI_MODULE_NAME("nsaccess")
  20
  21 /*******************************************************************************
  22  *
  23  * FUNCTION:    acpi_ns_root_initialize
  24  *
  25  * PARAMETERS:  None
  26  *
  27  * RETURN:      Status
  28  *
  29  * DESCRIPTION: Allocate and initialize the default root named objects
  30  *
  31  * MUTEX:       Locks namespace for entire execution
  32  *
  33  ******************************************************************************/
  34 acpi_status acpi_ns_root_initialize(void)
  35 {
  36         acpi_status status;
  37         const struct acpi_predefined_names *init_val = NULL;
  38         struct acpi_namespace_node *new_node;
  39         union acpi_operand_object *obj_desc;
  40         acpi_string val = NULL;
  41
  42         ACPI_FUNCTION_TRACE(ns_root_initialize);
  43
  44         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
  45         if (ACPI_FAILURE(status)) {
  46                 return_ACPI_STATUS(status);
  47         }
  48
  49         /*
  50          * The global root ptr is initially NULL, so a non-NULL value indicates
  51          * that acpi_ns_root_initialize() has already been called; just return.
  52          */
  53         if (acpi_gbl_root_node) {
  54                 status = AE_OK;
  55                 goto unlock_and_exit;
  56         }
  57
  58         /*
  59          * Tell the rest of the subsystem that the root is initialized
  60          * (This is OK because the namespace is locked)
  61          */
  62         acpi_gbl_root_node = &acpi_gbl_root_node_struct;
  63
  64         /* Enter the pre-defined names in the name table */
  65
  66         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  67                           "Entering predefined entries into namespace\n"));
  68
  69         for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {
  70
  71                 /* _OSI is optional for now, will be permanent later */
  72
  73                 if (!strcmp(init_val->name, "_OSI")
  74                     && !acpi_gbl_create_osi_method) {
  75                         continue;
  76                 }
  77
  78                 status =
  79                     acpi_ns_lookup(NULL, ACPI_CAST_PTR(char, init_val->name),
  80                                    init_val->type, ACPI_IMODE_LOAD_PASS2,
  81                                    ACPI_NS_NO_UPSEARCH, NULL, &new_node);
  82                 if (ACPI_FAILURE(status)) {
  83                         ACPI_EXCEPTION((AE_INFO, status,
  84                                         "Could not create predefined name %s",
  85                                         init_val->name));
  86                         continue;
  87                 }
  88
  89                 /*
  90                  * Name entered successfully. If entry in pre_defined_names[] specifies
  91                  * an initial value, create the initial value.
  92                  */
  93                 if (init_val->val) {
  94                         status = acpi_os_predefined_override(init_val, &val);
  95                         if (ACPI_FAILURE(status)) {
  96                                 ACPI_ERROR((AE_INFO,
  97                                             "Could not override predefined %s",
  98                                             init_val->name));
  99                         }
 100
 101                         if (!val) {
 102                                 val = init_val->val;
 103                         }
 104
 105                         /*
 106                          * Entry requests an initial value, allocate a
 107                          * descriptor for it.
 108                          */
 109                         obj_desc =
 110                             acpi_ut_create_internal_object(init_val->type);
 111                         if (!obj_desc) {
 112                                 status = AE_NO_MEMORY;
 113                                 goto unlock_and_exit;
 114                         }
 115
 116                         /*
 117                          * Convert value string from table entry to
 118                          * internal representation. Only types actually
 119                          * used for initial values are implemented here.
 120                          */
 121                         switch (init_val->type) {
 122                         case ACPI_TYPE_METHOD:
 123
 124                                 obj_desc->method.param_count =
 125                                     (u8) ACPI_TO_INTEGER(val);
 126                                 obj_desc->common.flags |= AOPOBJ_DATA_VALID;
 127
 128 #if defined (ACPI_ASL_COMPILER)
 129
 130                                 /* Save the parameter count for the iASL compiler */
 131
 132                                 new_node->value = obj_desc->method.param_count;
 133 #else
 134                                 /* Mark this as a very SPECIAL method */
 135
 136                                 obj_desc->method.info_flags =
 137                                     ACPI_METHOD_INTERNAL_ONLY;
 138                                 obj_desc->method.dispatch.implementation =
 139                                     acpi_ut_osi_implementation;
 140 #endif
 141                                 break;
 142
 143                         case ACPI_TYPE_INTEGER:
 144
 145                                 obj_desc->integer.value = ACPI_TO_INTEGER(val);
 146                                 break;
 147
 148                         case ACPI_TYPE_STRING:
 149
 150                                 /* Build an object around the static string */
 151
 152                                 obj_desc->string.length = (u32)strlen(val);
 153                                 obj_desc->string.pointer = val;
 154                                 obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
 155                                 break;
 156
 157                         case ACPI_TYPE_MUTEX:
 158
 159                                 obj_desc->mutex.node = new_node;
 160                                 obj_desc->mutex.sync_level =
 161                                     (u8) (ACPI_TO_INTEGER(val) - 1);
 162
 163                                 /* Create a mutex */
 164
 165                                 status =
 166                                     acpi_os_create_mutex(&obj_desc->mutex.
 167                                                          os_mutex);
 168                                 if (ACPI_FAILURE(status)) {
 169                                         acpi_ut_remove_reference(obj_desc);
 170                                         goto unlock_and_exit;
 171                                 }
 172
 173                                 /* Special case for ACPI Global Lock */
 174
 175                                 if (strcmp(init_val->name, "_GL_") == 0) {
 176                                         acpi_gbl_global_lock_mutex = obj_desc;
 177
 178                                         /* Create additional counting semaphore for global lock */
 179
 180                                         status =
 181                                             acpi_os_create_semaphore(1, 0,
 182                                                                      &acpi_gbl_global_lock_semaphore);
 183                                         if (ACPI_FAILURE(status)) {
 184                                                 acpi_ut_remove_reference
 185                                                     (obj_desc);
 186                                                 goto unlock_and_exit;
 187                                         }
 188                                 }
 189                                 break;
 190
 191                         default:
 192
 193                                 ACPI_ERROR((AE_INFO,
 194                                             "Unsupported initial type value 0x%X",
 195                                             init_val->type));
 196                                 acpi_ut_remove_reference(obj_desc);
 197                                 obj_desc = NULL;
 198                                 continue;
 199                         }
 200
 201                         /* Store pointer to value descriptor in the Node */
 202
 203                         status = acpi_ns_attach_object(new_node, obj_desc,
 204                                                        obj_desc->common.type);
 205
 206                         /* Remove local reference to the object */
 207
 208                         acpi_ut_remove_reference(obj_desc);
 209                 }
 210         }
 211
 212 unlock_and_exit:
 213         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 214
 215         /* Save a handle to "_GPE", it is always present */
 216
 217         if (ACPI_SUCCESS(status)) {
 218                 status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
 219                                           &acpi_gbl_fadt_gpe_device);
 220         }
 221
 222         return_ACPI_STATUS(status);
 223 }
 224
 225 /*******************************************************************************
 226  *
 227  * FUNCTION:    acpi_ns_lookup
 228  *
 229  * PARAMETERS:  scope_info      - Current scope info block
 230  *              pathname        - Search pathname, in internal format
 231  *                                (as represented in the AML stream)
 232  *              type            - Type associated with name
 233  *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
 234  *              flags           - Flags describing the search restrictions
 235  *              walk_state      - Current state of the walk
 236  *              return_node     - Where the Node is placed (if found
 237  *                                or created successfully)
 238  *
 239  * RETURN:      Status
 240  *
 241  * DESCRIPTION: Find or enter the passed name in the name space.
 242  *              Log an error if name not found in Exec mode.
 243  *
 244  * MUTEX:       Assumes namespace is locked.
 245  *
 246  ******************************************************************************/
 247
 248 acpi_status
 249 acpi_ns_lookup(union acpi_generic_state *scope_info,
 250                char *pathname,
 251                acpi_object_type type,
 252                acpi_interpreter_mode interpreter_mode,
 253                u32 flags,
 254                struct acpi_walk_state *walk_state,
 255                struct acpi_namespace_node **return_node)
 256 {
 257         acpi_status status;
 258         char *path = pathname;
 259         char *external_path;
 260         struct acpi_namespace_node *prefix_node;
 261         struct acpi_namespace_node *current_node = NULL;
 262         struct acpi_namespace_node *this_node = NULL;
 263         u32 num_segments;
 264         u32 num_carats;
 265         acpi_name simple_name;
 266         acpi_object_type type_to_check_for;
 267         acpi_object_type this_search_type;
 268         u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
 269         u32 local_flags;
 270
 271         ACPI_FUNCTION_TRACE(ns_lookup);
 272
 273         if (!return_node) {
 274                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 275         }
 276
 277         local_flags = flags &
 278             ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
 279               ACPI_NS_SEARCH_PARENT);
 280         *return_node = ACPI_ENTRY_NOT_FOUND;
 281         acpi_gbl_ns_lookup_count++;
 282
 283         if (!acpi_gbl_root_node) {
 284                 return_ACPI_STATUS(AE_NO_NAMESPACE);
 285         }
 286
 287         /* Get the prefix scope. A null scope means use the root scope */
 288
 289         if ((!scope_info) || (!scope_info->scope.node)) {
 290                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 291                                   "Null scope prefix, using root node (%p)\n",
 292                                   acpi_gbl_root_node));
 293
 294                 prefix_node = acpi_gbl_root_node;
 295         } else {
 296                 prefix_node = scope_info->scope.node;
 297                 if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
 298                     ACPI_DESC_TYPE_NAMED) {
 299                         ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
 300                                     prefix_node,
 301                                     acpi_ut_get_descriptor_name(prefix_node)));
 302                         return_ACPI_STATUS(AE_AML_INTERNAL);
 303                 }
 304
 305                 if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
 306                         /*
 307                          * This node might not be a actual "scope" node (such as a
 308                          * Device/Method, etc.)  It could be a Package or other object
 309                          * node. Backup up the tree to find the containing scope node.
 310                          */
 311                         while (!acpi_ns_opens_scope(prefix_node->type) &&
 312                                prefix_node->type != ACPI_TYPE_ANY) {
 313                                 prefix_node = prefix_node->parent;
 314                         }
 315                 }
 316         }
 317
 318         /* Save type. TBD: may be no longer necessary */
 319
 320         type_to_check_for = type;
 321
 322         /*
 323          * Begin examination of the actual pathname
 324          */
 325         if (!pathname) {
 326
 327                 /* A Null name_path is allowed and refers to the root */
 328
 329                 num_segments = 0;
 330                 this_node = acpi_gbl_root_node;
 331                 path = "";
 332
 333                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 334                                   "Null Pathname (Zero segments), Flags=%X\n",
 335                                   flags));
 336         } else {
 337                 /*
 338                  * Name pointer is valid (and must be in internal name format)
 339                  *
 340                  * Check for scope prefixes:
 341                  *
 342                  * As represented in the AML stream, a namepath consists of an
 343                  * optional scope prefix followed by a name segment part.
 344                  *
 345                  * If present, the scope prefix is either a Root Prefix (in
 346                  * which case the name is fully qualified), or one or more
 347                  * Parent Prefixes (in which case the name's scope is relative
 348                  * to the current scope).
 349                  */
 350                 if (*path == (u8) AML_ROOT_PREFIX) {
 351
 352                         /* Pathname is fully qualified, start from the root */
 353
 354                         this_node = acpi_gbl_root_node;
 355                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 356
 357                         /* Point to name segment part */
 358
 359                         path++;
 360
 361                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 362                                           "Path is absolute from root [%p]\n",
 363                                           this_node));
 364                 } else {
 365                         /* Pathname is relative to current scope, start there */
 366
 367                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 368                                           "Searching relative to prefix scope [%4.4s] (%p)\n",
 369                                           acpi_ut_get_node_name(prefix_node),
 370                                           prefix_node));
 371
 372                         /*
 373                          * Handle multiple Parent Prefixes (carat) by just getting
 374                          * the parent node for each prefix instance.
 375                          */
 376                         this_node = prefix_node;
 377                         num_carats = 0;
 378                         while (*path == (u8) AML_PARENT_PREFIX) {
 379
 380                                 /* Name is fully qualified, no search rules apply */
 381
 382                                 search_parent_flag = ACPI_NS_NO_UPSEARCH;
 383
 384                                 /*
 385                                  * Point past this prefix to the name segment
 386                                  * part or the next Parent Prefix
 387                                  */
 388                                 path++;
 389
 390                                 /* Backup to the parent node */
 391
 392                                 num_carats++;
 393                                 this_node = this_node->parent;
 394                                 if (!this_node) {
 395                                         /*
 396                                          * Current scope has no parent scope. Externalize
 397                                          * the internal path for error message.
 398                                          */
 399                                         status =
 400                                             acpi_ns_externalize_name
 401                                             (ACPI_UINT32_MAX, pathname, NULL,
 402                                              &external_path);
 403                                         if (ACPI_SUCCESS(status)) {
 404                                                 ACPI_ERROR((AE_INFO,
 405                                                             "%s: Path has too many parent prefixes (^)",
 406                                                             external_path));
 407
 408                                                 ACPI_FREE(external_path);
 409                                         }
 410
 411                                         return_ACPI_STATUS(AE_NOT_FOUND);
 412                                 }
 413                         }
 414
 415                         if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
 416                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 417                                                   "Search scope is [%4.4s], path has %u carat(s)\n",
 418                                                   acpi_ut_get_node_name
 419                                                   (this_node), num_carats));
 420                         }
 421                 }
 422
 423                 /*
 424                  * Determine the number of ACPI name segments in this pathname.
 425                  *
 426                  * The segment part consists of either:
 427                  *  - A Null name segment (0)
 428                  *  - A dual_name_prefix followed by two 4-byte name segments
 429                  *  - A multi_name_prefix followed by a byte indicating the
 430                  *      number of segments and the segments themselves.
 431                  *  - A single 4-byte name segment
 432                  *
 433                  * Examine the name prefix opcode, if any, to determine the number of
 434                  * segments.
 435                  */
 436                 switch (*path) {
 437                 case 0:
 438                         /*
 439                          * Null name after a root or parent prefixes. We already
 440                          * have the correct target node and there are no name segments.
 441                          */
 442                         num_segments = 0;
 443                         type = this_node->type;
 444
 445                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 446                                           "Prefix-only Pathname (Zero name segments), Flags=%X\n",
 447                                           flags));
 448                         break;
 449
 450                 case AML_DUAL_NAME_PREFIX:
 451
 452                         /* More than one name_seg, search rules do not apply */
 453
 454                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 455
 456                         /* Two segments, point to first name segment */
 457
 458                         num_segments = 2;
 459                         path++;
 460
 461                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 462                                           "Dual Pathname (2 segments, Flags=%X)\n",
 463                                           flags));
 464                         break;
 465
 466                 case AML_MULTI_NAME_PREFIX:
 467
 468                         /* More than one name_seg, search rules do not apply */
 469
 470                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 471
 472                         /* Extract segment count, point to first name segment */
 473
 474                         path++;
 475                         num_segments = (u32) (u8) * path;
 476                         path++;
 477
 478                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 479                                           "Multi Pathname (%u Segments, Flags=%X)\n",
 480                                           num_segments, flags));
 481                         break;
 482
 483                 default:
 484                         /*
 485                          * Not a Null name, no Dual or Multi prefix, hence there is
 486                          * only one name segment and Pathname is already pointing to it.
 487                          */
 488                         num_segments = 1;
 489
 490                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 491                                           "Simple Pathname (1 segment, Flags=%X)\n",
 492                                           flags));
 493                         break;
 494                 }
 495
 496                 ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
 497         }
 498
 499         /*
 500          * Search namespace for each segment of the name. Loop through and
 501          * verify (or add to the namespace) each name segment.
 502          *
 503          * The object type is significant only at the last name
 504          * segment. (We don't care about the types along the path, only
 505          * the type of the final target object.)
 506          */
 507         this_search_type = ACPI_TYPE_ANY;
 508         current_node = this_node;
 509         while (num_segments && current_node) {
 510                 num_segments--;
 511                 if (!num_segments) {
 512
 513                         /* This is the last segment, enable typechecking */
 514
 515                         this_search_type = type;
 516
 517                         /*
 518                          * Only allow automatic parent search (search rules) if the caller
 519                          * requested it AND we have a single, non-fully-qualified name_seg
 520                          */
 521                         if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
 522                             (flags & ACPI_NS_SEARCH_PARENT)) {
 523                                 local_flags |= ACPI_NS_SEARCH_PARENT;
 524                         }
 525
 526                         /* Set error flag according to caller */
 527
 528                         if (flags & ACPI_NS_ERROR_IF_FOUND) {
 529                                 local_flags |= ACPI_NS_ERROR_IF_FOUND;
 530                         }
 531
 532                         /* Set override flag according to caller */
 533
 534                         if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
 535                                 local_flags |= ACPI_NS_OVERRIDE_IF_FOUND;
 536                         }
 537                 }
 538
 539                 /* Extract one ACPI name from the front of the pathname */
 540
 541                 ACPI_MOVE_32_TO_32(&simple_name, path);
 542
 543                 /* Try to find the single (4 character) ACPI name */
 544
 545                 status =
 546                     acpi_ns_search_and_enter(simple_name, walk_state,
 547                                              current_node, interpreter_mode,
 548                                              this_search_type, local_flags,
 549                                              &this_node);
 550                 if (ACPI_FAILURE(status)) {
 551                         if (status == AE_NOT_FOUND) {
 552
 553                                 /* Name not found in ACPI namespace */
 554
 555                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 556                                                   "Name [%4.4s] not found in scope [%4.4s] %p\n",
 557                                                   (char *)&simple_name,
 558                                                   (char *)&current_node->name,
 559                                                   current_node));
 560                         }
 561 #ifdef ACPI_ASL_COMPILER
 562                         /*
 563                          * If this ACPI name already exists within the namespace as an
 564                          * external declaration, then mark the external as a conflicting
 565                          * declaration and proceed to process the current node as if it did
 566                          * not exist in the namespace. If this node is not processed as
 567                          * normal, then it could cause improper namespace resolution
 568                          * by failing to open a new scope.
 569                          */
 570                         if (acpi_gbl_disasm_flag &&
 571                             (status == AE_ALREADY_EXISTS) &&
 572                             ((this_node->flags & ANOBJ_IS_EXTERNAL) ||
 573                              (walk_state
 574                               && walk_state->opcode == AML_EXTERNAL_OP))) {
 575                                 this_node->flags &= ~ANOBJ_IS_EXTERNAL;
 576                                 this_node->type = (u8)this_search_type;
 577                                 if (walk_state->opcode != AML_EXTERNAL_OP) {
 578                                         acpi_dm_mark_external_conflict
 579                                             (this_node);
 580                                 }
 581                                 break;
 582                         }
 583 #endif
 584
 585                         *return_node = this_node;
 586                         return_ACPI_STATUS(status);
 587                 }
 588
 589                 /* More segments to follow? */
 590
 591                 if (num_segments > 0) {
 592                         /*
 593                          * If we have an alias to an object that opens a scope (such as a
 594                          * device or processor), we need to dereference the alias here so
 595                          * that we can access any children of the original node (via the
 596                          * remaining segments).
 597                          */
 598                         if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
 599                                 if (!this_node->object) {
 600                                         return_ACPI_STATUS(AE_NOT_EXIST);
 601                                 }
 602
 603                                 if (acpi_ns_opens_scope
 604                                     (((struct acpi_namespace_node *)
 605                                       this_node->object)->type)) {
 606                                         this_node =
 607                                             (struct acpi_namespace_node *)
 608                                             this_node->object;
 609                                 }
 610                         }
 611                 }
 612
 613                 /* Special handling for the last segment (num_segments == 0) */
 614
 615                 else {
 616 #ifdef ACPI_ASL_COMPILER
 617                         if (!acpi_gbl_disasm_flag
 618                             && (this_node->flags & ANOBJ_IS_EXTERNAL)) {
 619                                 this_node->flags &= ~IMPLICIT_EXTERNAL;
 620                         }
 621 #endif
 622
 623                         /*
 624                          * Sanity typecheck of the target object:
 625                          *
 626                          * If 1) This is the last segment (num_segments == 0)
 627                          *    2) And we are looking for a specific type
 628                          *       (Not checking for TYPE_ANY)
 629                          *    3) Which is not an alias
 630                          *    4) Which is not a local type (TYPE_SCOPE)
 631                          *    5) And the type of target object is known (not TYPE_ANY)
 632                          *    6) And target object does not match what we are looking for
 633                          *
 634                          * Then we have a type mismatch. Just warn and ignore it.
 635                          */
 636                         if ((type_to_check_for != ACPI_TYPE_ANY) &&
 637                             (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
 638                             (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
 639                             && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
 640                             && (this_node->type != ACPI_TYPE_ANY)
 641                             && (this_node->type != type_to_check_for)) {
 642
 643                                 /* Complain about a type mismatch */
 644
 645                                 ACPI_WARNING((AE_INFO,
 646                                               "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
 647                                               ACPI_CAST_PTR(char, &simple_name),
 648                                               acpi_ut_get_type_name(this_node->
 649                                                                     type),
 650                                               acpi_ut_get_type_name
 651                                               (type_to_check_for)));
 652                         }
 653
 654                         /*
 655                          * If this is the last name segment and we are not looking for a
 656                          * specific type, but the type of found object is known, use that
 657                          * type to (later) see if it opens a scope.
 658                          */
 659                         if (type == ACPI_TYPE_ANY) {
 660                                 type = this_node->type;
 661                         }
 662                 }
 663
 664                 /* Point to next name segment and make this node current */
 665
 666                 path += ACPI_NAME_SIZE;
 667                 current_node = this_node;
 668         }
 669
 670         /* Always check if we need to open a new scope */
 671
 672         if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
 673                 /*
 674                  * If entry is a type which opens a scope, push the new scope on the
 675                  * scope stack.
 676                  */
 677                 if (acpi_ns_opens_scope(type)) {
 678                         status =
 679                             acpi_ds_scope_stack_push(this_node, type,
 680                                                      walk_state);
 681                         if (ACPI_FAILURE(status)) {
 682                                 return_ACPI_STATUS(status);
 683                         }
 684                 }
 685         }
 686
 687         *return_node = this_node;
 688         return_ACPI_STATUS(AE_OK);
 689 }