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 - 2005, 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
  45 #include <acpi/acpi.h>
  46 #include <acpi/amlcode.h>
  47 #include <acpi/acnamesp.h>
  48 #include <acpi/acdispat.h>
  49
  50
  51 #define _COMPONENT          ACPI_NAMESPACE
  52          ACPI_MODULE_NAME    ("nsaccess")
  53
  54
  55 /*******************************************************************************
  56  *
  57  * FUNCTION:    acpi_ns_root_initialize
  58  *
  59  * PARAMETERS:  None
  60  *
  61  * RETURN:      Status
  62  *
  63  * DESCRIPTION: Allocate and initialize the default root named objects
  64  *
  65  * MUTEX:       Locks namespace for entire execution
  66  *
  67  ******************************************************************************/
  68
  69 acpi_status
  70 acpi_ns_root_initialize (
  71         void)
  72 {
  73         acpi_status                         status;
  74         const struct acpi_predefined_names *init_val = NULL;
  75         struct acpi_namespace_node          *new_node;
  76         union acpi_operand_object           *obj_desc;
  77         acpi_string                         val = NULL;
  78
  79
  80         ACPI_FUNCTION_TRACE ("ns_root_initialize");
  81
  82
  83         status = acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);
  84         if (ACPI_FAILURE (status)) {
  85                 return_ACPI_STATUS (status);
  86         }
  87
  88         /*
  89          * The global root ptr is initially NULL, so a non-NULL value indicates
  90          * that acpi_ns_root_initialize() has already been called; just return.
  91          */
  92         if (acpi_gbl_root_node) {
  93                 status = AE_OK;
  94                 goto unlock_and_exit;
  95         }
  96
  97         /*
  98          * Tell the rest of the subsystem that the root is initialized
  99          * (This is OK because the namespace is locked)
 100          */
 101         acpi_gbl_root_node = &acpi_gbl_root_node_struct;
 102
 103         /* Enter the pre-defined names in the name table */
 104
 105         ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
 106                 "Entering predefined entries into namespace\n"));
 107
 108         for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {
 109                 /* _OSI is optional for now, will be permanent later */
 110
 111                 if (!ACPI_STRCMP (init_val->name, "_OSI") && !acpi_gbl_create_osi_method) {
 112                         continue;
 113                 }
 114
 115                 status = acpi_ns_lookup (NULL, init_val->name, init_val->type,
 116                                   ACPI_IMODE_LOAD_PASS2, ACPI_NS_NO_UPSEARCH,
 117                                   NULL, &new_node);
 118
 119                 if (ACPI_FAILURE (status) || (!new_node)) /* Must be on same line for code converter */ {
 120                         ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 121                                 "Could not create predefined name %s, %s\n",
 122                                 init_val->name, acpi_format_exception (status)));
 123                 }
 124
 125                 /*
 126                  * Name entered successfully.
 127                  * If entry in pre_defined_names[] specifies an
 128                  * initial value, create the initial value.
 129                  */
 130                 if (init_val->val) {
 131                         status = acpi_os_predefined_override (init_val, &val);
 132                         if (ACPI_FAILURE (status)) {
 133                                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 134                                         "Could not override predefined %s\n",
 135                                         init_val->name));
 136                         }
 137
 138                         if (!val) {
 139                                 val = init_val->val;
 140                         }
 141
 142                         /*
 143                          * Entry requests an initial value, allocate a
 144                          * descriptor for it.
 145                          */
 146                         obj_desc = acpi_ut_create_internal_object (init_val->type);
 147                         if (!obj_desc) {
 148                                 status = AE_NO_MEMORY;
 149                                 goto unlock_and_exit;
 150                         }
 151
 152                         /*
 153                          * Convert value string from table entry to
 154                          * internal representation. Only types actually
 155                          * used for initial values are implemented here.
 156                          */
 157                         switch (init_val->type) {
 158                         case ACPI_TYPE_METHOD:
 159                                 obj_desc->method.param_count = (u8) ACPI_TO_INTEGER (val);
 160                                 obj_desc->common.flags |= AOPOBJ_DATA_VALID;
 161
 162 #if defined (ACPI_ASL_COMPILER)
 163
 164                                 /* save the parameter count for the i_aSL compiler */
 165
 166                                 new_node->value = obj_desc->method.param_count;
 167 #else
 168                                 /* Mark this as a very SPECIAL method */
 169
 170                                 obj_desc->method.method_flags = AML_METHOD_INTERNAL_ONLY;
 171
 172 #ifndef ACPI_DUMP_APP
 173                                 obj_desc->method.implementation = acpi_ut_osi_implementation;
 174 #endif
 175 #endif
 176                                 break;
 177
 178                         case ACPI_TYPE_INTEGER:
 179
 180                                 obj_desc->integer.value = ACPI_TO_INTEGER (val);
 181                                 break;
 182
 183
 184                         case ACPI_TYPE_STRING:
 185
 186                                 /*
 187                                  * Build an object around the static string
 188                                  */
 189                                 obj_desc->string.length = (u32) ACPI_STRLEN (val);
 190                                 obj_desc->string.pointer = val;
 191                                 obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
 192                                 break;
 193
 194
 195                         case ACPI_TYPE_MUTEX:
 196
 197                                 obj_desc->mutex.node = new_node;
 198                                 obj_desc->mutex.sync_level = (u8) (ACPI_TO_INTEGER (val) - 1);
 199
 200                                 if (ACPI_STRCMP (init_val->name, "_GL_") == 0) {
 201                                         /*
 202                                          * Create a counting semaphore for the
 203                                          * global lock
 204                                          */
 205                                         status = acpi_os_create_semaphore (ACPI_NO_UNIT_LIMIT,
 206                                                          1, &obj_desc->mutex.semaphore);
 207                                         if (ACPI_FAILURE (status)) {
 208                                                 acpi_ut_remove_reference (obj_desc);
 209                                                 goto unlock_and_exit;
 210                                         }
 211
 212                                         /*
 213                                          * We just created the mutex for the
 214                                          * global lock, save it
 215                                          */
 216                                         acpi_gbl_global_lock_semaphore = obj_desc->mutex.semaphore;
 217                                 }
 218                                 else {
 219                                         /* Create a mutex */
 220
 221                                         status = acpi_os_create_semaphore (1, 1,
 222                                                            &obj_desc->mutex.semaphore);
 223                                         if (ACPI_FAILURE (status)) {
 224                                                 acpi_ut_remove_reference (obj_desc);
 225                                                 goto unlock_and_exit;
 226                                         }
 227                                 }
 228                                 break;
 229
 230
 231                         default:
 232
 233                                 ACPI_REPORT_ERROR (("Unsupported initial type value %X\n",
 234                                         init_val->type));
 235                                 acpi_ut_remove_reference (obj_desc);
 236                                 obj_desc = NULL;
 237                                 continue;
 238                         }
 239
 240                         /* Store pointer to value descriptor in the Node */
 241
 242                         status = acpi_ns_attach_object (new_node, obj_desc,
 243                                          ACPI_GET_OBJECT_TYPE (obj_desc));
 244
 245                         /* Remove local reference to the object */
 246
 247                         acpi_ut_remove_reference (obj_desc);
 248                 }
 249         }
 250
 251
 252 unlock_and_exit:
 253         (void) acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
 254
 255         /* Save a handle to "_GPE", it is always present */
 256
 257         if (ACPI_SUCCESS (status)) {
 258                 status = acpi_ns_get_node_by_path ("\\_GPE", NULL, ACPI_NS_NO_UPSEARCH,
 259                                   &acpi_gbl_fadt_gpe_device);
 260         }
 261
 262         return_ACPI_STATUS (status);
 263 }
 264
 265
 266 /*******************************************************************************
 267  *
 268  * FUNCTION:    acpi_ns_lookup
 269  *
 270  * PARAMETERS:  scope_info      - Current scope info block
 271  *              Pathname        - Search pathname, in internal format
 272  *                                (as represented in the AML stream)
 273  *              Type            - Type associated with name
 274  *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
 275  *              Flags           - Flags describing the search restrictions
 276  *              walk_state      - Current state of the walk
 277  *              return_node     - Where the Node is placed (if found
 278  *                                or created successfully)
 279  *
 280  * RETURN:      Status
 281  *
 282  * DESCRIPTION: Find or enter the passed name in the name space.
 283  *              Log an error if name not found in Exec mode.
 284  *
 285  * MUTEX:       Assumes namespace is locked.
 286  *
 287  ******************************************************************************/
 288
 289 acpi_status
 290 acpi_ns_lookup (
 291         union acpi_generic_state        *scope_info,
 292         char                            *pathname,
 293         acpi_object_type                type,
 294         acpi_interpreter_mode           interpreter_mode,
 295         u32                             flags,
 296         struct acpi_walk_state          *walk_state,
 297         struct acpi_namespace_node      **return_node)
 298 {
 299         acpi_status                     status;
 300         char                            *path = pathname;
 301         struct acpi_namespace_node      *prefix_node;
 302         struct acpi_namespace_node      *current_node = NULL;
 303         struct acpi_namespace_node      *this_node = NULL;
 304         u32                             num_segments;
 305         u32                             num_carats;
 306         acpi_name                       simple_name;
 307         acpi_object_type                type_to_check_for;
 308         acpi_object_type                this_search_type;
 309         u32                             search_parent_flag = ACPI_NS_SEARCH_PARENT;
 310         u32                             local_flags = flags & ~(ACPI_NS_ERROR_IF_FOUND |
 311                            ACPI_NS_SEARCH_PARENT);
 312
 313
 314         ACPI_FUNCTION_TRACE ("ns_lookup");
 315
 316
 317         if (!return_node) {
 318                 return_ACPI_STATUS (AE_BAD_PARAMETER);
 319         }
 320
 321         acpi_gbl_ns_lookup_count++;
 322         *return_node = ACPI_ENTRY_NOT_FOUND;
 323
 324         if (!acpi_gbl_root_node) {
 325                 return_ACPI_STATUS (AE_NO_NAMESPACE);
 326         }
 327
 328         /*
 329          * Get the prefix scope.
 330          * A null scope means use the root scope
 331          */
 332         if ((!scope_info) ||
 333                 (!scope_info->scope.node)) {
 334                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 335                         "Null scope prefix, using root node (%p)\n",
 336                         acpi_gbl_root_node));
 337
 338                 prefix_node = acpi_gbl_root_node;
 339         }
 340         else {
 341                 prefix_node = scope_info->scope.node;
 342                 if (ACPI_GET_DESCRIPTOR_TYPE (prefix_node) != ACPI_DESC_TYPE_NAMED) {
 343                         ACPI_REPORT_ERROR (("ns_lookup: %p is not a namespace node [%s]\n",
 344                                         prefix_node, acpi_ut_get_descriptor_name (prefix_node)));
 345                         return_ACPI_STATUS (AE_AML_INTERNAL);
 346                 }
 347
 348                 /*
 349                  * This node might not be a actual "scope" node (such as a
 350                  * Device/Method, etc.)  It could be a Package or other object node.
 351                  * Backup up the tree to find the containing scope node.
 352                  */
 353                 while (!acpi_ns_opens_scope (prefix_node->type) &&
 354                                 prefix_node->type != ACPI_TYPE_ANY) {
 355                         prefix_node = acpi_ns_get_parent_node (prefix_node);
 356                 }
 357         }
 358
 359         /* Save type   TBD: may be no longer necessary */
 360
 361         type_to_check_for = type;
 362
 363         /*
 364          * Begin examination of the actual pathname
 365          */
 366         if (!pathname) {
 367                 /* A Null name_path is allowed and refers to the root */
 368
 369                 num_segments = 0;
 370                 this_node    = acpi_gbl_root_node;
 371                 path     = "";
 372
 373                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 374                         "Null Pathname (Zero segments), Flags=%X\n", flags));
 375         }
 376         else {
 377                 /*
 378                  * Name pointer is valid (and must be in internal name format)
 379                  *
 380                  * Check for scope prefixes:
 381                  *
 382                  * As represented in the AML stream, a namepath consists of an
 383                  * optional scope prefix followed by a name segment part.
 384                  *
 385                  * If present, the scope prefix is either a Root Prefix (in
 386                  * which case the name is fully qualified), or one or more
 387                  * Parent Prefixes (in which case the name's scope is relative
 388                  * to the current scope).
 389                  */
 390                 if (*path == (u8) AML_ROOT_PREFIX) {
 391                         /* Pathname is fully qualified, start from the root */
 392
 393                         this_node = acpi_gbl_root_node;
 394                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 395
 396                         /* Point to name segment part */
 397
 398                         path++;
 399
 400                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 401                                 "Path is absolute from root [%p]\n", this_node));
 402                 }
 403                 else {
 404                         /* Pathname is relative to current scope, start there */
 405
 406                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 407                                 "Searching relative to prefix scope [%4.4s] (%p)\n",
 408                                 acpi_ut_get_node_name (prefix_node), prefix_node));
 409
 410                         /*
 411                          * Handle multiple Parent Prefixes (carat) by just getting
 412                          * the parent node for each prefix instance.
 413                          */
 414                         this_node = prefix_node;
 415                         num_carats = 0;
 416                         while (*path == (u8) AML_PARENT_PREFIX) {
 417                                 /* Name is fully qualified, no search rules apply */
 418
 419                                 search_parent_flag = ACPI_NS_NO_UPSEARCH;
 420                                 /*
 421                                  * Point past this prefix to the name segment
 422                                  * part or the next Parent Prefix
 423                                  */
 424                                 path++;
 425
 426                                 /* Backup to the parent node */
 427
 428                                 num_carats++;
 429                                 this_node = acpi_ns_get_parent_node (this_node);
 430                                 if (!this_node) {
 431                                         /* Current scope has no parent scope */
 432
 433                                         ACPI_REPORT_ERROR (
 434                                                 ("ACPI path has too many parent prefixes (^) - reached beyond root node\n"));
 435                                         return_ACPI_STATUS (AE_NOT_FOUND);
 436                                 }
 437                         }
 438
 439                         if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
 440                                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 441                                         "Search scope is [%4.4s], path has %d carat(s)\n",
 442                                         acpi_ut_get_node_name (this_node), num_carats));
 443                         }
 444                 }
 445
 446                 /*
 447                  * Determine the number of ACPI name segments in this pathname.
 448                  *
 449                  * The segment part consists of either:
 450                  *  - A Null name segment (0)
 451                  *  - A dual_name_prefix followed by two 4-byte name segments
 452                  *  - A multi_name_prefix followed by a byte indicating the
 453                  *      number of segments and the segments themselves.
 454                  *  - A single 4-byte name segment
 455                  *
 456                  * Examine the name prefix opcode, if any, to determine the number of
 457                  * segments.
 458                  */
 459                 switch (*path) {
 460                 case 0:
 461                         /*
 462                          * Null name after a root or parent prefixes. We already
 463                          * have the correct target node and there are no name segments.
 464                          */
 465                         num_segments = 0;
 466                         type = this_node->type;
 467
 468                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 469                                 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
 470                                 flags));
 471                         break;
 472
 473                 case AML_DUAL_NAME_PREFIX:
 474
 475                         /* More than one name_seg, search rules do not apply */
 476
 477                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 478
 479                         /* Two segments, point to first name segment */
 480
 481                         num_segments = 2;
 482                         path++;
 483
 484                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 485                                 "Dual Pathname (2 segments, Flags=%X)\n", flags));
 486                         break;
 487
 488                 case AML_MULTI_NAME_PREFIX_OP:
 489
 490                         /* More than one name_seg, search rules do not apply */
 491
 492                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 493
 494                         /* Extract segment count, point to first name segment */
 495
 496                         path++;
 497                         num_segments = (u32) (u8) *path;
 498                         path++;
 499
 500                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 501                                 "Multi Pathname (%d Segments, Flags=%X) \n",
 502                                 num_segments, flags));
 503                         break;
 504
 505                 default:
 506                         /*
 507                          * Not a Null name, no Dual or Multi prefix, hence there is
 508                          * only one name segment and Pathname is already pointing to it.
 509                          */
 510                         num_segments = 1;
 511
 512                         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 513                                 "Simple Pathname (1 segment, Flags=%X)\n", flags));
 514                         break;
 515                 }
 516
 517                 ACPI_DEBUG_EXEC (acpi_ns_print_pathname (num_segments, path));
 518         }
 519
 520
 521         /*
 522          * Search namespace for each segment of the name.  Loop through and
 523          * verify (or add to the namespace) each name segment.
 524          *
 525          * The object type is significant only at the last name
 526          * segment.  (We don't care about the types along the path, only
 527          * the type of the final target object.)
 528          */
 529         this_search_type = ACPI_TYPE_ANY;
 530         current_node = this_node;
 531         while (num_segments && current_node) {
 532                 num_segments--;
 533                 if (!num_segments) {
 534                         /*
 535                          * This is the last segment, enable typechecking
 536                          */
 537                         this_search_type = type;
 538
 539                         /*
 540                          * Only allow automatic parent search (search rules) if the caller
 541                          * requested it AND we have a single, non-fully-qualified name_seg
 542                          */
 543                         if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
 544                                 (flags & ACPI_NS_SEARCH_PARENT)) {
 545                                 local_flags |= ACPI_NS_SEARCH_PARENT;
 546                         }
 547
 548                         /* Set error flag according to caller */
 549
 550                         if (flags & ACPI_NS_ERROR_IF_FOUND) {
 551                                 local_flags |= ACPI_NS_ERROR_IF_FOUND;
 552                         }
 553                 }
 554
 555                 /* Extract one ACPI name from the front of the pathname */
 556
 557                 ACPI_MOVE_32_TO_32 (&simple_name, path);
 558
 559                 /* Try to find the single (4 character) ACPI name */
 560
 561                 status = acpi_ns_search_and_enter (simple_name, walk_state, current_node,
 562                                  interpreter_mode, this_search_type, local_flags, &this_node);
 563                 if (ACPI_FAILURE (status)) {
 564                         if (status == AE_NOT_FOUND) {
 565                                 /* Name not found in ACPI namespace */
 566
 567                                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 568                                         "Name [%4.4s] not found in scope [%4.4s] %p\n",
 569                                         (char *) &simple_name, (char *) &current_node->name,
 570                                         current_node));
 571                         }
 572
 573                         *return_node = this_node;
 574                         return_ACPI_STATUS (status);
 575                 }
 576
 577                 /*
 578                  * Sanity typecheck of the target object:
 579                  *
 580                  * If 1) This is the last segment (num_segments == 0)
 581                  *    2) And we are looking for a specific type
 582                  *       (Not checking for TYPE_ANY)
 583                  *    3) Which is not an alias
 584                  *    4) Which is not a local type (TYPE_SCOPE)
 585                  *    5) And the type of target object is known (not TYPE_ANY)
 586                  *    6) And target object does not match what we are looking for
 587                  *
 588                  * Then we have a type mismatch.  Just warn and ignore it.
 589                  */
 590                 if ((num_segments       == 0)                               &&
 591                         (type_to_check_for  != ACPI_TYPE_ANY)                   &&
 592                         (type_to_check_for  != ACPI_TYPE_LOCAL_ALIAS)           &&
 593                         (type_to_check_for  != ACPI_TYPE_LOCAL_METHOD_ALIAS)    &&
 594                         (type_to_check_for  != ACPI_TYPE_LOCAL_SCOPE)           &&
 595                         (this_node->type    != ACPI_TYPE_ANY)                   &&
 596                         (this_node->type    != type_to_check_for)) {
 597                         /* Complain about a type mismatch */
 598
 599                         ACPI_REPORT_WARNING (
 600                                 ("ns_lookup: Type mismatch on %4.4s (%s), searching for (%s)\n",
 601                                 (char *) &simple_name, acpi_ut_get_type_name (this_node->type),
 602                                 acpi_ut_get_type_name (type_to_check_for)));
 603                 }
 604
 605                 /*
 606                  * If this is the last name segment and we are not looking for a
 607                  * specific type, but the type of found object is known, use that type
 608                  * to see if it opens a scope.
 609                  */
 610                 if ((num_segments == 0) && (type == ACPI_TYPE_ANY)) {
 611                         type = this_node->type;
 612                 }
 613
 614                 /* Point to next name segment and make this node current */
 615
 616                 path += ACPI_NAME_SIZE;
 617                 current_node = this_node;
 618         }
 619
 620         /*
 621          * Always check if we need to open a new scope
 622          */
 623         if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
 624                 /*
 625                  * If entry is a type which opens a scope, push the new scope on the
 626                  * scope stack.
 627                  */
 628                 if (acpi_ns_opens_scope (type)) {
 629                         status = acpi_ds_scope_stack_push (this_node, type, walk_state);
 630                         if (ACPI_FAILURE (status)) {
 631                                 return_ACPI_STATUS (status);
 632                         }
 633                 }
 634         }
 635
 636         *return_node = this_node;
 637         return_ACPI_STATUS (AE_OK);
 638 }
 639