drivers/acpi/namespace/nsaccess.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2006, R. Byron Moore
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include <acpi/amlcode.h>
  46 #include <acpi/acnamesp.h>
  47 #include <acpi/acdispat.h>
  48
  49 #define _COMPONENT          ACPI_NAMESPACE
  50 ACPI_MODULE_NAME("nsaccess")
  51
  52 /*******************************************************************************
  53  *
  54  * FUNCTION:    acpi_ns_root_initialize
  55  *
  56  * PARAMETERS:  None
  57  *
  58  * RETURN:      Status
  59  *
  60  * DESCRIPTION: Allocate and initialize the default root named objects
  61  *
  62  * MUTEX:       Locks namespace for entire execution
  63  *
  64  ******************************************************************************/
  65 acpi_status acpi_ns_root_initialize(void)
  66 {
  67         acpi_status status;
  68         const struct acpi_predefined_names *init_val = NULL;
  69         struct acpi_namespace_node *new_node;
  70         union acpi_operand_object *obj_desc;
  71         acpi_string val = NULL;
  72
  73         ACPI_FUNCTION_TRACE("ns_root_initialize");
  74
  75         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
  76         if (ACPI_FAILURE(status)) {
  77                 return_ACPI_STATUS(status);
  78         }
  79
  80         /*
  81          * The global root ptr is initially NULL, so a non-NULL value indicates
  82          * that acpi_ns_root_initialize() has already been called; just return.
  83          */
  84         if (acpi_gbl_root_node) {
  85                 status = AE_OK;
  86                 goto unlock_and_exit;
  87         }
  88
  89         /*
  90          * Tell the rest of the subsystem that the root is initialized
  91          * (This is OK because the namespace is locked)
  92          */
  93         acpi_gbl_root_node = &acpi_gbl_root_node_struct;
  94
  95         /* Enter the pre-defined names in the name table */
  96
  97         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  98                           "Entering predefined entries into namespace\n"));
  99
 100         for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {
 101                 /* _OSI is optional for now, will be permanent later */
 102
 103                 if (!ACPI_STRCMP(init_val->name, "_OSI")
 104                     && !acpi_gbl_create_osi_method) {
 105                         continue;
 106                 }
 107
 108                 status = acpi_ns_lookup(NULL, init_val->name, init_val->type,
 109                                         ACPI_IMODE_LOAD_PASS2,
 110                                         ACPI_NS_NO_UPSEARCH, NULL, &new_node);
 111
 112                 if (ACPI_FAILURE(status) || (!new_node)) {      /* Must be on same line for code converter */
 113                         ACPI_REPORT_ERROR(("Could not create predefined name %s, %s\n", init_val->name, acpi_format_exception(status)));
 114                 }
 115
 116                 /*
 117                  * Name entered successfully.
 118                  * If entry in pre_defined_names[] specifies an
 119                  * initial value, create the initial value.
 120                  */
 121                 if (init_val->val) {
 122                         status = acpi_os_predefined_override(init_val, &val);
 123                         if (ACPI_FAILURE(status)) {
 124                                 ACPI_REPORT_ERROR(("Could not override predefined %s\n", init_val->name));
 125                         }
 126
 127                         if (!val) {
 128                                 val = init_val->val;
 129                         }
 130
 131                         /*
 132                          * Entry requests an initial value, allocate a
 133                          * descriptor for it.
 134                          */
 135                         obj_desc =
 136                             acpi_ut_create_internal_object(init_val->type);
 137                         if (!obj_desc) {
 138                                 status = AE_NO_MEMORY;
 139                                 goto unlock_and_exit;
 140                         }
 141
 142                         /*
 143                          * Convert value string from table entry to
 144                          * internal representation. Only types actually
 145                          * used for initial values are implemented here.
 146                          */
 147                         switch (init_val->type) {
 148                         case ACPI_TYPE_METHOD:
 149                                 obj_desc->method.param_count =
 150                                     (u8) ACPI_TO_INTEGER(val);
 151                                 obj_desc->common.flags |= AOPOBJ_DATA_VALID;
 152
 153 #if defined (ACPI_ASL_COMPILER)
 154
 155                                 /* save the parameter count for the i_aSL compiler */
 156
 157                                 new_node->value = obj_desc->method.param_count;
 158 #else
 159                                 /* Mark this as a very SPECIAL method */
 160
 161                                 obj_desc->method.method_flags =
 162                                     AML_METHOD_INTERNAL_ONLY;
 163
 164 #ifndef ACPI_DUMP_APP
 165                                 obj_desc->method.implementation =
 166                                     acpi_ut_osi_implementation;
 167 #endif
 168 #endif
 169                                 break;
 170
 171                         case ACPI_TYPE_INTEGER:
 172
 173                                 obj_desc->integer.value = ACPI_TO_INTEGER(val);
 174                                 break;
 175
 176                         case ACPI_TYPE_STRING:
 177
 178                                 /*
 179                                  * Build an object around the static string
 180                                  */
 181                                 obj_desc->string.length =
 182                                     (u32) ACPI_STRLEN(val);
 183                                 obj_desc->string.pointer = val;
 184                                 obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
 185                                 break;
 186
 187                         case ACPI_TYPE_MUTEX:
 188
 189                                 obj_desc->mutex.node = new_node;
 190                                 obj_desc->mutex.sync_level =
 191                                     (u8) (ACPI_TO_INTEGER(val) - 1);
 192
 193                                 if (ACPI_STRCMP(init_val->name, "_GL_") == 0) {
 194                                         /*
 195                                          * Create a counting semaphore for the
 196                                          * global lock
 197                                          */
 198                                         status =
 199                                             acpi_os_create_semaphore
 200                                             (ACPI_NO_UNIT_LIMIT, 1,
 201                                              &obj_desc->mutex.semaphore);
 202                                         if (ACPI_FAILURE(status)) {
 203                                                 acpi_ut_remove_reference
 204                                                     (obj_desc);
 205                                                 goto unlock_and_exit;
 206                                         }
 207
 208                                         /*
 209                                          * We just created the mutex for the
 210                                          * global lock, save it
 211                                          */
 212                                         acpi_gbl_global_lock_semaphore =
 213                                             obj_desc->mutex.semaphore;
 214                                 } else {
 215                                         /* Create a mutex */
 216
 217                                         status = acpi_os_create_semaphore(1, 1,
 218                                                                           &obj_desc->
 219                                                                           mutex.
 220                                                                           semaphore);
 221                                         if (ACPI_FAILURE(status)) {
 222                                                 acpi_ut_remove_reference
 223                                                     (obj_desc);
 224                                                 goto unlock_and_exit;
 225                                         }
 226                                 }
 227                                 break;
 228
 229                         default:
 230
 231                                 ACPI_REPORT_ERROR(("Unsupported initial type value %X\n", init_val->type));
 232                                 acpi_ut_remove_reference(obj_desc);
 233                                 obj_desc = NULL;
 234                                 continue;
 235                         }
 236
 237                         /* Store pointer to value descriptor in the Node */
 238
 239                         status = acpi_ns_attach_object(new_node, obj_desc,
 240                                                        ACPI_GET_OBJECT_TYPE
 241                                                        (obj_desc));
 242
 243                         /* Remove local reference to the object */
 244
 245                         acpi_ut_remove_reference(obj_desc);
 246                 }
 247         }
 248
 249       unlock_and_exit:
 250         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 251
 252         /* Save a handle to "_GPE", it is always present */
 253
 254         if (ACPI_SUCCESS(status)) {
 255                 status =
 256                     acpi_ns_get_node_by_path("\\_GPE", NULL,
 257                                              ACPI_NS_NO_UPSEARCH,
 258                                              &acpi_gbl_fadt_gpe_device);
 259         }
 260
 261         return_ACPI_STATUS(status);
 262 }
 263
 264 /*******************************************************************************
 265  *
 266  * FUNCTION:    acpi_ns_lookup
 267  *
 268  * PARAMETERS:  scope_info      - Current scope info block
 269  *              Pathname        - Search pathname, in internal format
 270  *                                (as represented in the AML stream)
 271  *              Type            - Type associated with name
 272  *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
 273  *              Flags           - Flags describing the search restrictions
 274  *              walk_state      - Current state of the walk
 275  *              return_node     - Where the Node is placed (if found
 276  *                                or created successfully)
 277  *
 278  * RETURN:      Status
 279  *
 280  * DESCRIPTION: Find or enter the passed name in the name space.
 281  *              Log an error if name not found in Exec mode.
 282  *
 283  * MUTEX:       Assumes namespace is locked.
 284  *
 285  ******************************************************************************/
 286
 287 acpi_status
 288 acpi_ns_lookup(union acpi_generic_state *scope_info,
 289                char *pathname,
 290                acpi_object_type type,
 291                acpi_interpreter_mode interpreter_mode,
 292                u32 flags,
 293                struct acpi_walk_state *walk_state,
 294                struct acpi_namespace_node **return_node)
 295 {
 296         acpi_status status;
 297         char *path = pathname;
 298         struct acpi_namespace_node *prefix_node;
 299         struct acpi_namespace_node *current_node = NULL;
 300         struct acpi_namespace_node *this_node = NULL;
 301         u32 num_segments;
 302         u32 num_carats;
 303         acpi_name simple_name;
 304         acpi_object_type type_to_check_for;
 305         acpi_object_type this_search_type;
 306         u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
 307         u32 local_flags = flags & ~(ACPI_NS_ERROR_IF_FOUND |
 308                                     ACPI_NS_SEARCH_PARENT);
 309
 310         ACPI_FUNCTION_TRACE("ns_lookup");
 311
 312         if (!return_node) {
 313                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 314         }
 315
 316         acpi_gbl_ns_lookup_count++;
 317         *return_node = ACPI_ENTRY_NOT_FOUND;
 318
 319         if (!acpi_gbl_root_node) {
 320                 return_ACPI_STATUS(AE_NO_NAMESPACE);
 321         }
 322
 323         /*
 324          * Get the prefix scope.
 325          * A null scope means use the root scope
 326          */
 327         if ((!scope_info) || (!scope_info->scope.node)) {
 328                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 329                                   "Null scope prefix, using root node (%p)\n",
 330                                   acpi_gbl_root_node));
 331
 332                 prefix_node = acpi_gbl_root_node;
 333         } else {
 334                 prefix_node = scope_info->scope.node;
 335                 if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
 336                     ACPI_DESC_TYPE_NAMED) {
 337                         ACPI_REPORT_ERROR(("%p is not a namespace node [%s]\n",
 338                                            prefix_node,
 339                                            acpi_ut_get_descriptor_name
 340                                            (prefix_node)));
 341                         return_ACPI_STATUS(AE_AML_INTERNAL);
 342                 }
 343
 344                 /*
 345                  * This node might not be a actual "scope" node (such as a
 346                  * Device/Method, etc.)  It could be a Package or other object node.
 347                  * Backup up the tree to find the containing scope node.
 348                  */
 349                 while (!acpi_ns_opens_scope(prefix_node->type) &&
 350                        prefix_node->type != ACPI_TYPE_ANY) {
 351                         prefix_node = acpi_ns_get_parent_node(prefix_node);
 352                 }
 353         }
 354
 355         /* Save type   TBD: may be no longer necessary */
 356
 357         type_to_check_for = type;
 358
 359         /*
 360          * Begin examination of the actual pathname
 361          */
 362         if (!pathname) {
 363                 /* A Null name_path is allowed and refers to the root */
 364
 365                 num_segments = 0;
 366                 this_node = acpi_gbl_root_node;
 367                 path = "";
 368
 369                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 370                                   "Null Pathname (Zero segments), Flags=%X\n",
 371                                   flags));
 372         } else {
 373                 /*
 374                  * Name pointer is valid (and must be in internal name format)
 375                  *
 376                  * Check for scope prefixes:
 377                  *
 378                  * As represented in the AML stream, a namepath consists of an
 379                  * optional scope prefix followed by a name segment part.
 380                  *
 381                  * If present, the scope prefix is either a Root Prefix (in
 382                  * which case the name is fully qualified), or one or more
 383                  * Parent Prefixes (in which case the name's scope is relative
 384                  * to the current scope).
 385                  */
 386                 if (*path == (u8) AML_ROOT_PREFIX) {
 387                         /* Pathname is fully qualified, start from the root */
 388
 389                         this_node = acpi_gbl_root_node;
 390                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 391
 392                         /* Point to name segment part */
 393
 394                         path++;
 395
 396                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 397                                           "Path is absolute from root [%p]\n",
 398                                           this_node));
 399                 } else {
 400                         /* Pathname is relative to current scope, start there */
 401
 402                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 403                                           "Searching relative to prefix scope [%4.4s] (%p)\n",
 404                                           acpi_ut_get_node_name(prefix_node),
 405                                           prefix_node));
 406
 407                         /*
 408                          * Handle multiple Parent Prefixes (carat) by just getting
 409                          * the parent node for each prefix instance.
 410                          */
 411                         this_node = prefix_node;
 412                         num_carats = 0;
 413                         while (*path == (u8) AML_PARENT_PREFIX) {
 414                                 /* Name is fully qualified, no search rules apply */
 415
 416                                 search_parent_flag = ACPI_NS_NO_UPSEARCH;
 417                                 /*
 418                                  * Point past this prefix to the name segment
 419                                  * part or the next Parent Prefix
 420                                  */
 421                                 path++;
 422
 423                                 /* Backup to the parent node */
 424
 425                                 num_carats++;
 426                                 this_node = acpi_ns_get_parent_node(this_node);
 427                                 if (!this_node) {
 428                                         /* Current scope has no parent scope */
 429
 430                                         ACPI_REPORT_ERROR(("ACPI path has too many parent prefixes (^) - reached beyond root node\n"));
 431                                         return_ACPI_STATUS(AE_NOT_FOUND);
 432                                 }
 433                         }
 434
 435                         if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
 436                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 437                                                   "Search scope is [%4.4s], path has %d carat(s)\n",
 438                                                   acpi_ut_get_node_name
 439                                                   (this_node), num_carats));
 440                         }
 441                 }
 442
 443                 /*
 444                  * Determine the number of ACPI name segments in this pathname.
 445                  *
 446                  * The segment part consists of either:
 447                  *  - A Null name segment (0)
 448                  *  - A dual_name_prefix followed by two 4-byte name segments
 449                  *  - A multi_name_prefix followed by a byte indicating the
 450                  *      number of segments and the segments themselves.
 451                  *  - A single 4-byte name segment
 452                  *
 453                  * Examine the name prefix opcode, if any, to determine the number of
 454                  * segments.
 455                  */
 456                 switch (*path) {
 457                 case 0:
 458                         /*
 459                          * Null name after a root or parent prefixes. We already
 460                          * have the correct target node and there are no name segments.
 461                          */
 462                         num_segments = 0;
 463                         type = this_node->type;
 464
 465                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 466                                           "Prefix-only Pathname (Zero name segments), Flags=%X\n",
 467                                           flags));
 468                         break;
 469
 470                 case AML_DUAL_NAME_PREFIX:
 471
 472                         /* More than one name_seg, search rules do not apply */
 473
 474                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 475
 476                         /* Two segments, point to first name segment */
 477
 478                         num_segments = 2;
 479                         path++;
 480
 481                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 482                                           "Dual Pathname (2 segments, Flags=%X)\n",
 483                                           flags));
 484                         break;
 485
 486                 case AML_MULTI_NAME_PREFIX_OP:
 487
 488                         /* More than one name_seg, search rules do not apply */
 489
 490                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 491
 492                         /* Extract segment count, point to first name segment */
 493
 494                         path++;
 495                         num_segments = (u32) (u8) * path;
 496                         path++;
 497
 498                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 499                                           "Multi Pathname (%d Segments, Flags=%X)\n",
 500                                           num_segments, flags));
 501                         break;
 502
 503                 default:
 504                         /*
 505                          * Not a Null name, no Dual or Multi prefix, hence there is
 506                          * only one name segment and Pathname is already pointing to it.
 507                          */
 508                         num_segments = 1;
 509
 510                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 511                                           "Simple Pathname (1 segment, Flags=%X)\n",
 512                                           flags));
 513                         break;
 514                 }
 515
 516                 ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
 517         }
 518
 519         /*
 520          * Search namespace for each segment of the name.  Loop through and
 521          * verify (or add to the namespace) each name segment.
 522          *
 523          * The object type is significant only at the last name
 524          * segment.  (We don't care about the types along the path, only
 525          * the type of the final target object.)
 526          */
 527         this_search_type = ACPI_TYPE_ANY;
 528         current_node = this_node;
 529         while (num_segments && current_node) {
 530                 num_segments--;
 531                 if (!num_segments) {
 532                         /*
 533                          * This is the last segment, enable typechecking
 534                          */
 535                         this_search_type = type;
 536
 537                         /*
 538                          * Only allow automatic parent search (search rules) if the caller
 539                          * requested it AND we have a single, non-fully-qualified name_seg
 540                          */
 541                         if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
 542                             (flags & ACPI_NS_SEARCH_PARENT)) {
 543                                 local_flags |= ACPI_NS_SEARCH_PARENT;
 544                         }
 545
 546                         /* Set error flag according to caller */
 547
 548                         if (flags & ACPI_NS_ERROR_IF_FOUND) {
 549                                 local_flags |= ACPI_NS_ERROR_IF_FOUND;
 550                         }
 551                 }
 552
 553                 /* Extract one ACPI name from the front of the pathname */
 554
 555                 ACPI_MOVE_32_TO_32(&simple_name, path);
 556
 557                 /* Try to find the single (4 character) ACPI name */
 558
 559                 status =
 560                     acpi_ns_search_and_enter(simple_name, walk_state,
 561                                              current_node, interpreter_mode,
 562                                              this_search_type, local_flags,
 563                                              &this_node);
 564                 if (ACPI_FAILURE(status)) {
 565                         if (status == AE_NOT_FOUND) {
 566                                 /* Name not found in ACPI namespace */
 567
 568                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 569                                                   "Name [%4.4s] not found in scope [%4.4s] %p\n",
 570                                                   (char *)&simple_name,
 571                                                   (char *)&current_node->name,
 572                                                   current_node));
 573                         }
 574
 575                         *return_node = this_node;
 576                         return_ACPI_STATUS(status);
 577                 }
 578
 579                 /*
 580                  * Sanity typecheck of the target object:
 581                  *
 582                  * If 1) This is the last segment (num_segments == 0)
 583                  *    2) And we are looking for a specific type
 584                  *       (Not checking for TYPE_ANY)
 585                  *    3) Which is not an alias
 586                  *    4) Which is not a local type (TYPE_SCOPE)
 587                  *    5) And the type of target object is known (not TYPE_ANY)
 588                  *    6) And target object does not match what we are looking for
 589                  *
 590                  * Then we have a type mismatch.  Just warn and ignore it.
 591                  */
 592                 if ((num_segments == 0) &&
 593                     (type_to_check_for != ACPI_TYPE_ANY) &&
 594                     (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
 595                     (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS) &&
 596                     (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE) &&
 597                     (this_node->type != ACPI_TYPE_ANY) &&
 598                     (this_node->type != type_to_check_for)) {
 599                         /* Complain about a type mismatch */
 600
 601                         ACPI_REPORT_WARNING(("ns_lookup: Type mismatch on %4.4s (%s), searching for (%s)\n", ACPI_CAST_PTR(char, &simple_name), acpi_ut_get_type_name(this_node->type), acpi_ut_get_type_name(type_to_check_for)));
 602                 }
 603
 604                 /*
 605                  * If this is the last name segment and we are not looking for a
 606                  * specific type, but the type of found object is known, use that type
 607                  * to see if it opens a scope.
 608                  */
 609                 if ((num_segments == 0) && (type == ACPI_TYPE_ANY)) {
 610                         type = this_node->type;
 611                 }
 612
 613                 /* Point to next name segment and make this node current */
 614
 615                 path += ACPI_NAME_SIZE;
 616                 current_node = this_node;
 617         }
 618
 619         /*
 620          * Always check if we need to open a new scope
 621          */
 622         if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
 623                 /*
 624                  * If entry is a type which opens a scope, push the new scope on the
 625                  * scope stack.
 626                  */
 627                 if (acpi_ns_opens_scope(type)) {
 628                         status =
 629                             acpi_ds_scope_stack_push(this_node, type,
 630                                                      walk_state);
 631                         if (ACPI_FAILURE(status)) {
 632                                 return_ACPI_STATUS(status);
 633                         }
 634                 }
 635         }
 636
 637         *return_node = this_node;
 638         return_ACPI_STATUS(AE_OK);
 639 }