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         struct acpi_namespace_node *prev_node = NULL;
  40         union acpi_operand_object *obj_desc;
  41         acpi_string val = NULL;
  42
  43         ACPI_FUNCTION_TRACE(ns_root_initialize);
  44
  45         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
  46         if (ACPI_FAILURE(status)) {
  47                 return_ACPI_STATUS(status);
  48         }
  49
  50         /*
  51          * The global root ptr is initially NULL, so a non-NULL value indicates
  52          * that acpi_ns_root_initialize() has already been called; just return.
  53          */
  54         if (acpi_gbl_root_node) {
  55                 status = AE_OK;
  56                 goto unlock_and_exit;
  57         }
  58
  59         /*
  60          * Tell the rest of the subsystem that the root is initialized
  61          * (This is OK because the namespace is locked)
  62          */
  63         acpi_gbl_root_node = &acpi_gbl_root_node_struct;
  64
  65         /* Enter the predefined names in the name table */
  66
  67         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  68                           "Entering predefined entries into namespace\n"));
  69
  70         /*
  71          * Create the initial (default) namespace.
  72          * This namespace looks like something similar to this:
  73          *
  74          *   ACPI Namespace (from Namespace Root):
  75          *    0  _GPE Scope        00203160 00
  76          *    0  _PR_ Scope        002031D0 00
  77          *    0  _SB_ Device       00203240 00 Notify Object: 0020ADD8
  78          *    0  _SI_ Scope        002032B0 00
  79          *    0  _TZ_ Device       00203320 00
  80          *    0  _REV Integer      00203390 00 = 0000000000000002
  81          *    0  _OS_ String       00203488 00 Len 14 "Microsoft Windows NT"
  82          *    0  _GL_ Mutex        00203580 00 Object 002035F0
  83          *    0  _OSI Method       00203678 00 Args 1 Len 0000 Aml 00000000
  84          */
  85         for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {
  86                 status = AE_OK;
  87
  88                 /* _OSI is optional for now, will be permanent later */
  89
  90                 if (!strcmp(init_val->name, "_OSI")
  91                     && !acpi_gbl_create_osi_method) {
  92                         continue;
  93                 }
  94
  95                 /*
  96                  * Create, init, and link the new predefined name
  97                  * Note: No need to use acpi_ns_lookup here because all the
  98                  * predefined names are at the root level. It is much easier to
  99                  * just create and link the new node(s) here.
 100                  */
 101                 new_node =
 102                     acpi_ns_create_node(*ACPI_CAST_PTR(u32, init_val->name));
 103                 if (!new_node) {
 104                         status = AE_NO_MEMORY;
 105                         goto unlock_and_exit;
 106                 }
 107
 108                 new_node->descriptor_type = ACPI_DESC_TYPE_NAMED;
 109                 new_node->type = init_val->type;
 110
 111                 if (!prev_node) {
 112                         acpi_gbl_root_node_struct.child = new_node;
 113                 } else {
 114                         prev_node->peer = new_node;
 115                 }
 116
 117                 new_node->parent = &acpi_gbl_root_node_struct;
 118                 prev_node = new_node;
 119
 120                 /*
 121                  * Name entered successfully. If entry in pre_defined_names[] specifies
 122                  * an initial value, create the initial value.
 123                  */
 124                 if (init_val->val) {
 125                         status = acpi_os_predefined_override(init_val, &val);
 126                         if (ACPI_FAILURE(status)) {
 127                                 ACPI_ERROR((AE_INFO,
 128                                             "Could not override predefined %s",
 129                                             init_val->name));
 130                         }
 131
 132                         if (!val) {
 133                                 val = init_val->val;
 134                         }
 135
 136                         /*
 137                          * Entry requests an initial value, allocate a
 138                          * descriptor for it.
 139                          */
 140                         obj_desc =
 141                             acpi_ut_create_internal_object(init_val->type);
 142                         if (!obj_desc) {
 143                                 status = AE_NO_MEMORY;
 144                                 goto unlock_and_exit;
 145                         }
 146
 147                         /*
 148                          * Convert value string from table entry to
 149                          * internal representation. Only types actually
 150                          * used for initial values are implemented here.
 151                          */
 152                         switch (init_val->type) {
 153                         case ACPI_TYPE_METHOD:
 154
 155                                 obj_desc->method.param_count =
 156                                     (u8) ACPI_TO_INTEGER(val);
 157                                 obj_desc->common.flags |= AOPOBJ_DATA_VALID;
 158
 159 #if defined (ACPI_ASL_COMPILER)
 160
 161                                 /* Save the parameter count for the iASL compiler */
 162
 163                                 new_node->value = obj_desc->method.param_count;
 164 #else
 165                                 /* Mark this as a very SPECIAL method (_OSI) */
 166
 167                                 obj_desc->method.info_flags =
 168                                     ACPI_METHOD_INTERNAL_ONLY;
 169                                 obj_desc->method.dispatch.implementation =
 170                                     acpi_ut_osi_implementation;
 171 #endif
 172                                 break;
 173
 174                         case ACPI_TYPE_INTEGER:
 175
 176                                 obj_desc->integer.value = ACPI_TO_INTEGER(val);
 177                                 break;
 178
 179                         case ACPI_TYPE_STRING:
 180
 181                                 /* Build an object around the static string */
 182
 183                                 obj_desc->string.length = (u32)strlen(val);
 184                                 obj_desc->string.pointer = val;
 185                                 obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
 186                                 break;
 187
 188                         case ACPI_TYPE_MUTEX:
 189
 190                                 obj_desc->mutex.node = new_node;
 191                                 obj_desc->mutex.sync_level =
 192                                     (u8) (ACPI_TO_INTEGER(val) - 1);
 193
 194                                 /* Create a mutex */
 195
 196                                 status =
 197                                     acpi_os_create_mutex(&obj_desc->mutex.
 198                                                          os_mutex);
 199                                 if (ACPI_FAILURE(status)) {
 200                                         acpi_ut_remove_reference(obj_desc);
 201                                         goto unlock_and_exit;
 202                                 }
 203
 204                                 /* Special case for ACPI Global Lock */
 205
 206                                 if (strcmp(init_val->name, "_GL_") == 0) {
 207                                         acpi_gbl_global_lock_mutex = obj_desc;
 208
 209                                         /* Create additional counting semaphore for global lock */
 210
 211                                         status =
 212                                             acpi_os_create_semaphore(1, 0,
 213                                                                      &acpi_gbl_global_lock_semaphore);
 214                                         if (ACPI_FAILURE(status)) {
 215                                                 acpi_ut_remove_reference
 216                                                     (obj_desc);
 217                                                 goto unlock_and_exit;
 218                                         }
 219                                 }
 220                                 break;
 221
 222                         default:
 223
 224                                 ACPI_ERROR((AE_INFO,
 225                                             "Unsupported initial type value 0x%X",
 226                                             init_val->type));
 227                                 acpi_ut_remove_reference(obj_desc);
 228                                 obj_desc = NULL;
 229                                 continue;
 230                         }
 231
 232                         /* Store pointer to value descriptor in the Node */
 233
 234                         status = acpi_ns_attach_object(new_node, obj_desc,
 235                                                        obj_desc->common.type);
 236
 237                         /* Remove local reference to the object */
 238
 239                         acpi_ut_remove_reference(obj_desc);
 240                 }
 241         }
 242
 243 unlock_and_exit:
 244         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 245
 246         /* Save a handle to "_GPE", it is always present */
 247
 248         if (ACPI_SUCCESS(status)) {
 249                 status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
 250                                           &acpi_gbl_fadt_gpe_device);
 251         }
 252
 253         return_ACPI_STATUS(status);
 254 }
 255
 256 /*******************************************************************************
 257  *
 258  * FUNCTION:    acpi_ns_lookup
 259  *
 260  * PARAMETERS:  scope_info      - Current scope info block
 261  *              pathname        - Search pathname, in internal format
 262  *                                (as represented in the AML stream)
 263  *              type            - Type associated with name
 264  *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
 265  *              flags           - Flags describing the search restrictions
 266  *              walk_state      - Current state of the walk
 267  *              return_node     - Where the Node is placed (if found
 268  *                                or created successfully)
 269  *
 270  * RETURN:      Status
 271  *
 272  * DESCRIPTION: Find or enter the passed name in the name space.
 273  *              Log an error if name not found in Exec mode.
 274  *
 275  * MUTEX:       Assumes namespace is locked.
 276  *
 277  ******************************************************************************/
 278
 279 acpi_status
 280 acpi_ns_lookup(union acpi_generic_state *scope_info,
 281                char *pathname,
 282                acpi_object_type type,
 283                acpi_interpreter_mode interpreter_mode,
 284                u32 flags,
 285                struct acpi_walk_state *walk_state,
 286                struct acpi_namespace_node **return_node)
 287 {
 288         acpi_status status;
 289         char *path = pathname;
 290         char *external_path;
 291         struct acpi_namespace_node *prefix_node;
 292         struct acpi_namespace_node *current_node = NULL;
 293         struct acpi_namespace_node *this_node = NULL;
 294         u32 num_segments;
 295         u32 num_carats;
 296         acpi_name simple_name;
 297         acpi_object_type type_to_check_for;
 298         acpi_object_type this_search_type;
 299         u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
 300         u32 local_flags;
 301         acpi_interpreter_mode local_interpreter_mode;
 302
 303         ACPI_FUNCTION_TRACE(ns_lookup);
 304
 305         if (!return_node) {
 306                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 307         }
 308
 309         local_flags = flags &
 310             ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
 311               ACPI_NS_SEARCH_PARENT);
 312         *return_node = ACPI_ENTRY_NOT_FOUND;
 313         acpi_gbl_ns_lookup_count++;
 314
 315         if (!acpi_gbl_root_node) {
 316                 return_ACPI_STATUS(AE_NO_NAMESPACE);
 317         }
 318
 319         /* Get the prefix scope. A null scope means use the root scope */
 320
 321         if ((!scope_info) || (!scope_info->scope.node)) {
 322                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 323                                   "Null scope prefix, using root node (%p)\n",
 324                                   acpi_gbl_root_node));
 325
 326                 prefix_node = acpi_gbl_root_node;
 327         } else {
 328                 prefix_node = scope_info->scope.node;
 329                 if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
 330                     ACPI_DESC_TYPE_NAMED) {
 331                         ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
 332                                     prefix_node,
 333                                     acpi_ut_get_descriptor_name(prefix_node)));
 334                         return_ACPI_STATUS(AE_AML_INTERNAL);
 335                 }
 336
 337                 if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
 338                         /*
 339                          * This node might not be a actual "scope" node (such as a
 340                          * Device/Method, etc.)  It could be a Package or other object
 341                          * node. Backup up the tree to find the containing scope node.
 342                          */
 343                         while (!acpi_ns_opens_scope(prefix_node->type) &&
 344                                prefix_node->type != ACPI_TYPE_ANY) {
 345                                 prefix_node = prefix_node->parent;
 346                         }
 347                 }
 348         }
 349
 350         /* Save type. TBD: may be no longer necessary */
 351
 352         type_to_check_for = type;
 353
 354         /*
 355          * Begin examination of the actual pathname
 356          */
 357         if (!pathname) {
 358
 359                 /* A Null name_path is allowed and refers to the root */
 360
 361                 num_segments = 0;
 362                 this_node = acpi_gbl_root_node;
 363                 path = "";
 364
 365                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 366                                   "Null Pathname (Zero segments), Flags=%X\n",
 367                                   flags));
 368         } else {
 369                 /*
 370                  * Name pointer is valid (and must be in internal name format)
 371                  *
 372                  * Check for scope prefixes:
 373                  *
 374                  * As represented in the AML stream, a namepath consists of an
 375                  * optional scope prefix followed by a name segment part.
 376                  *
 377                  * If present, the scope prefix is either a Root Prefix (in
 378                  * which case the name is fully qualified), or one or more
 379                  * Parent Prefixes (in which case the name's scope is relative
 380                  * to the current scope).
 381                  */
 382                 if (*path == (u8) AML_ROOT_PREFIX) {
 383
 384                         /* Pathname is fully qualified, start from the root */
 385
 386                         this_node = acpi_gbl_root_node;
 387                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 388
 389                         /* Point to name segment part */
 390
 391                         path++;
 392
 393                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 394                                           "Path is absolute from root [%p]\n",
 395                                           this_node));
 396                 } else {
 397                         /* Pathname is relative to current scope, start there */
 398
 399                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 400                                           "Searching relative to prefix scope [%4.4s] (%p)\n",
 401                                           acpi_ut_get_node_name(prefix_node),
 402                                           prefix_node));
 403
 404                         /*
 405                          * Handle multiple Parent Prefixes (carat) by just getting
 406                          * the parent node for each prefix instance.
 407                          */
 408                         this_node = prefix_node;
 409                         num_carats = 0;
 410                         while (*path == (u8) AML_PARENT_PREFIX) {
 411
 412                                 /* Name is fully qualified, no search rules apply */
 413
 414                                 search_parent_flag = ACPI_NS_NO_UPSEARCH;
 415
 416                                 /*
 417                                  * Point past this prefix to the name segment
 418                                  * part or the next Parent Prefix
 419                                  */
 420                                 path++;
 421
 422                                 /* Backup to the parent node */
 423
 424                                 num_carats++;
 425                                 this_node = this_node->parent;
 426                                 if (!this_node) {
 427                                         /*
 428                                          * Current scope has no parent scope. Externalize
 429                                          * the internal path for error message.
 430                                          */
 431                                         status =
 432                                             acpi_ns_externalize_name
 433                                             (ACPI_UINT32_MAX, pathname, NULL,
 434                                              &external_path);
 435                                         if (ACPI_SUCCESS(status)) {
 436                                                 ACPI_ERROR((AE_INFO,
 437                                                             "%s: Path has too many parent prefixes (^)",
 438                                                             external_path));
 439
 440                                                 ACPI_FREE(external_path);
 441                                         }
 442
 443                                         return_ACPI_STATUS(AE_NOT_FOUND);
 444                                 }
 445                         }
 446
 447                         if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
 448                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 449                                                   "Search scope is [%4.4s], path has %u carat(s)\n",
 450                                                   acpi_ut_get_node_name
 451                                                   (this_node), num_carats));
 452                         }
 453                 }
 454
 455                 /*
 456                  * Determine the number of ACPI name segments in this pathname.
 457                  *
 458                  * The segment part consists of either:
 459                  *  - A Null name segment (0)
 460                  *  - A dual_name_prefix followed by two 4-byte name segments
 461                  *  - A multi_name_prefix followed by a byte indicating the
 462                  *      number of segments and the segments themselves.
 463                  *  - A single 4-byte name segment
 464                  *
 465                  * Examine the name prefix opcode, if any, to determine the number of
 466                  * segments.
 467                  */
 468                 switch (*path) {
 469                 case 0:
 470                         /*
 471                          * Null name after a root or parent prefixes. We already
 472                          * have the correct target node and there are no name segments.
 473                          */
 474                         num_segments = 0;
 475                         type = this_node->type;
 476
 477                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 478                                           "Prefix-only Pathname (Zero name segments), Flags=%X\n",
 479                                           flags));
 480                         break;
 481
 482                 case AML_DUAL_NAME_PREFIX:
 483
 484                         /* More than one name_seg, search rules do not apply */
 485
 486                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 487
 488                         /* Two segments, point to first name segment */
 489
 490                         num_segments = 2;
 491                         path++;
 492
 493                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 494                                           "Dual Pathname (2 segments, Flags=%X)\n",
 495                                           flags));
 496                         break;
 497
 498                 case AML_MULTI_NAME_PREFIX:
 499
 500                         /* More than one name_seg, search rules do not apply */
 501
 502                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 503
 504                         /* Extract segment count, point to first name segment */
 505
 506                         path++;
 507                         num_segments = (u32) (u8) * path;
 508                         path++;
 509
 510                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 511                                           "Multi Pathname (%u Segments, Flags=%X)\n",
 512                                           num_segments, flags));
 513                         break;
 514
 515                 default:
 516                         /*
 517                          * Not a Null name, no Dual or Multi prefix, hence there is
 518                          * only one name segment and Pathname is already pointing to it.
 519                          */
 520                         num_segments = 1;
 521
 522                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 523                                           "Simple Pathname (1 segment, Flags=%X)\n",
 524                                           flags));
 525                         break;
 526                 }
 527
 528                 ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
 529         }
 530
 531         /*
 532          * Search namespace for each segment of the name. Loop through and
 533          * verify (or add to the namespace) each name segment.
 534          *
 535          * The object type is significant only at the last name
 536          * segment. (We don't care about the types along the path, only
 537          * the type of the final target object.)
 538          */
 539         this_search_type = ACPI_TYPE_ANY;
 540         current_node = this_node;
 541
 542         while (num_segments && current_node) {
 543                 num_segments--;
 544                 if (!num_segments) {
 545
 546                         /* This is the last segment, enable typechecking */
 547
 548                         this_search_type = type;
 549
 550                         /*
 551                          * Only allow automatic parent search (search rules) if the caller
 552                          * requested it AND we have a single, non-fully-qualified name_seg
 553                          */
 554                         if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
 555                             (flags & ACPI_NS_SEARCH_PARENT)) {
 556                                 local_flags |= ACPI_NS_SEARCH_PARENT;
 557                         }
 558
 559                         /* Set error flag according to caller */
 560
 561                         if (flags & ACPI_NS_ERROR_IF_FOUND) {
 562                                 local_flags |= ACPI_NS_ERROR_IF_FOUND;
 563                         }
 564
 565                         /* Set override flag according to caller */
 566
 567                         if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
 568                                 local_flags |= ACPI_NS_OVERRIDE_IF_FOUND;
 569                         }
 570                 }
 571
 572                 /* Handle opcodes that create a new name_seg via a full name_path */
 573
 574                 local_interpreter_mode = interpreter_mode;
 575                 if ((flags & ACPI_NS_PREFIX_MUST_EXIST) && (num_segments > 0)) {
 576
 577                         /* Every element of the path must exist (except for the final name_seg) */
 578
 579                         local_interpreter_mode = ACPI_IMODE_EXECUTE;
 580                 }
 581
 582                 /* Extract one ACPI name from the front of the pathname */
 583
 584                 ACPI_MOVE_32_TO_32(&simple_name, path);
 585
 586                 /* Try to find the single (4 character) ACPI name */
 587
 588                 status =
 589                     acpi_ns_search_and_enter(simple_name, walk_state,
 590                                              current_node,
 591                                              local_interpreter_mode,
 592                                              this_search_type, local_flags,
 593                                              &this_node);
 594                 if (ACPI_FAILURE(status)) {
 595                         if (status == AE_NOT_FOUND) {
 596 #if !defined ACPI_ASL_COMPILER  /* Note: iASL reports this error by itself, not needed here */
 597                                 if (flags & ACPI_NS_PREFIX_MUST_EXIST) {
 598                                         acpi_os_printf(ACPI_MSG_BIOS_ERROR
 599                                                        "Object does not exist: %4.4s\n",
 600                                                        (char *)&simple_name);
 601                                 }
 602 #endif
 603                                 /* Name not found in ACPI namespace */
 604
 605                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 606                                                   "Name [%4.4s] not found in scope [%4.4s] %p\n",
 607                                                   (char *)&simple_name,
 608                                                   (char *)&current_node->name,
 609                                                   current_node));
 610                         }
 611 #ifdef ACPI_EXEC_APP
 612                         if ((status == AE_ALREADY_EXISTS) &&
 613                             (this_node->flags & ANOBJ_NODE_EARLY_INIT)) {
 614                                 this_node->flags &= ~ANOBJ_NODE_EARLY_INIT;
 615                                 status = AE_OK;
 616                         }
 617 #endif
 618
 619 #ifdef ACPI_ASL_COMPILER
 620                         /*
 621                          * If this ACPI name already exists within the namespace as an
 622                          * external declaration, then mark the external as a conflicting
 623                          * declaration and proceed to process the current node as if it did
 624                          * not exist in the namespace. If this node is not processed as
 625                          * normal, then it could cause improper namespace resolution
 626                          * by failing to open a new scope.
 627                          */
 628                         if (acpi_gbl_disasm_flag &&
 629                             (status == AE_ALREADY_EXISTS) &&
 630                             ((this_node->flags & ANOBJ_IS_EXTERNAL) ||
 631                              (walk_state
 632                               && walk_state->opcode == AML_EXTERNAL_OP))) {
 633                                 this_node->flags &= ~ANOBJ_IS_EXTERNAL;
 634                                 this_node->type = (u8)this_search_type;
 635                                 if (walk_state->opcode != AML_EXTERNAL_OP) {
 636                                         acpi_dm_mark_external_conflict
 637                                             (this_node);
 638                                 }
 639                                 break;
 640                         }
 641 #endif
 642
 643                         *return_node = this_node;
 644                         return_ACPI_STATUS(status);
 645                 }
 646
 647                 /* More segments to follow? */
 648
 649                 if (num_segments > 0) {
 650                         /*
 651                          * If we have an alias to an object that opens a scope (such as a
 652                          * device or processor), we need to dereference the alias here so
 653                          * that we can access any children of the original node (via the
 654                          * remaining segments).
 655                          */
 656                         if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
 657                                 if (!this_node->object) {
 658                                         return_ACPI_STATUS(AE_NOT_EXIST);
 659                                 }
 660
 661                                 if (acpi_ns_opens_scope
 662                                     (((struct acpi_namespace_node *)
 663                                       this_node->object)->type)) {
 664                                         this_node =
 665                                             (struct acpi_namespace_node *)
 666                                             this_node->object;
 667                                 }
 668                         }
 669                 }
 670
 671                 /* Special handling for the last segment (num_segments == 0) */
 672
 673                 else {
 674                         /*
 675                          * Sanity typecheck of the target object:
 676                          *
 677                          * If 1) This is the last segment (num_segments == 0)
 678                          *    2) And we are looking for a specific type
 679                          *       (Not checking for TYPE_ANY)
 680                          *    3) Which is not an alias
 681                          *    4) Which is not a local type (TYPE_SCOPE)
 682                          *    5) And the type of target object is known (not TYPE_ANY)
 683                          *    6) And target object does not match what we are looking for
 684                          *
 685                          * Then we have a type mismatch. Just warn and ignore it.
 686                          */
 687                         if ((type_to_check_for != ACPI_TYPE_ANY) &&
 688                             (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
 689                             (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
 690                             && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
 691                             && (this_node->type != ACPI_TYPE_ANY)
 692                             && (this_node->type != type_to_check_for)) {
 693
 694                                 /* Complain about a type mismatch */
 695
 696                                 ACPI_WARNING((AE_INFO,
 697                                               "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
 698                                               ACPI_CAST_PTR(char, &simple_name),
 699                                               acpi_ut_get_type_name(this_node->
 700                                                                     type),
 701                                               acpi_ut_get_type_name
 702                                               (type_to_check_for)));
 703                         }
 704
 705                         /*
 706                          * If this is the last name segment and we are not looking for a
 707                          * specific type, but the type of found object is known, use that
 708                          * type to (later) see if it opens a scope.
 709                          */
 710                         if (type == ACPI_TYPE_ANY) {
 711                                 type = this_node->type;
 712                         }
 713                 }
 714
 715                 /* Point to next name segment and make this node current */
 716
 717                 path += ACPI_NAMESEG_SIZE;
 718                 current_node = this_node;
 719         }
 720
 721         /* Always check if we need to open a new scope */
 722
 723         if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
 724                 /*
 725                  * If entry is a type which opens a scope, push the new scope on the
 726                  * scope stack.
 727                  */
 728                 if (acpi_ns_opens_scope(type)) {
 729                         status =
 730                             acpi_ds_scope_stack_push(this_node, type,
 731                                                      walk_state);
 732                         if (ACPI_FAILURE(status)) {
 733                                 return_ACPI_STATUS(status);
 734                         }
 735                 }
 736         }
 737 #ifdef ACPI_EXEC_APP
 738         if (flags & ACPI_NS_EARLY_INIT) {
 739                 this_node->flags |= ANOBJ_NODE_EARLY_INIT;
 740         }
 741 #endif
 742
 743         *return_node = this_node;
 744         return_ACPI_STATUS(AE_OK);
 745 }