drivers/acpi/acpica/nsaccess.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2018, Intel Corp.
   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 "accommon.h"
  46 #include "amlcode.h"
  47 #include "acnamesp.h"
  48 #include "acdispat.h"
  49
  50 #ifdef ACPI_ASL_COMPILER
  51 #include "acdisasm.h"
  52 #endif
  53
  54 #define _COMPONENT          ACPI_NAMESPACE
  55 ACPI_MODULE_NAME("nsaccess")
  56
  57 /*******************************************************************************
  58  *
  59  * FUNCTION:    acpi_ns_root_initialize
  60  *
  61  * PARAMETERS:  None
  62  *
  63  * RETURN:      Status
  64  *
  65  * DESCRIPTION: Allocate and initialize the default root named objects
  66  *
  67  * MUTEX:       Locks namespace for entire execution
  68  *
  69  ******************************************************************************/
  70 acpi_status acpi_ns_root_initialize(void)
  71 {
  72         acpi_status status;
  73         const struct acpi_predefined_names *init_val = NULL;
  74         struct acpi_namespace_node *new_node;
  75         union acpi_operand_object *obj_desc;
  76         acpi_string val = NULL;
  77
  78         ACPI_FUNCTION_TRACE(ns_root_initialize);
  79
  80         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
  81         if (ACPI_FAILURE(status)) {
  82                 return_ACPI_STATUS(status);
  83         }
  84
  85         /*
  86          * The global root ptr is initially NULL, so a non-NULL value indicates
  87          * that acpi_ns_root_initialize() has already been called; just return.
  88          */
  89         if (acpi_gbl_root_node) {
  90                 status = AE_OK;
  91                 goto unlock_and_exit;
  92         }
  93
  94         /*
  95          * Tell the rest of the subsystem that the root is initialized
  96          * (This is OK because the namespace is locked)
  97          */
  98         acpi_gbl_root_node = &acpi_gbl_root_node_struct;
  99
 100         /* Enter the pre-defined names in the name table */
 101
 102         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 103                           "Entering predefined entries into namespace\n"));
 104
 105         for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {
 106
 107                 /* _OSI is optional for now, will be permanent later */
 108
 109                 if (!strcmp(init_val->name, "_OSI")
 110                     && !acpi_gbl_create_osi_method) {
 111                         continue;
 112                 }
 113
 114                 status =
 115                     acpi_ns_lookup(NULL, ACPI_CAST_PTR(char, init_val->name),
 116                                    init_val->type, ACPI_IMODE_LOAD_PASS2,
 117                                    ACPI_NS_NO_UPSEARCH, NULL, &new_node);
 118                 if (ACPI_FAILURE(status)) {
 119                         ACPI_EXCEPTION((AE_INFO, status,
 120                                         "Could not create predefined name %s",
 121                                         init_val->name));
 122                         continue;
 123                 }
 124
 125                 /*
 126                  * Name entered successfully. If entry in pre_defined_names[] specifies
 127                  * an initial value, create the initial value.
 128                  */
 129                 if (init_val->val) {
 130                         status = acpi_os_predefined_override(init_val, &val);
 131                         if (ACPI_FAILURE(status)) {
 132                                 ACPI_ERROR((AE_INFO,
 133                                             "Could not override predefined %s",
 134                                             init_val->name));
 135                         }
 136
 137                         if (!val) {
 138                                 val = init_val->val;
 139                         }
 140
 141                         /*
 142                          * Entry requests an initial value, allocate a
 143                          * descriptor for it.
 144                          */
 145                         obj_desc =
 146                             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
 160                                 obj_desc->method.param_count =
 161                                     (u8) ACPI_TO_INTEGER(val);
 162                                 obj_desc->common.flags |= AOPOBJ_DATA_VALID;
 163
 164 #if defined (ACPI_ASL_COMPILER)
 165
 166                                 /* Save the parameter count for the iASL compiler */
 167
 168                                 new_node->value = obj_desc->method.param_count;
 169 #else
 170                                 /* Mark this as a very SPECIAL method */
 171
 172                                 obj_desc->method.info_flags =
 173                                     ACPI_METHOD_INTERNAL_ONLY;
 174                                 obj_desc->method.dispatch.implementation =
 175                                     acpi_ut_osi_implementation;
 176 #endif
 177                                 break;
 178
 179                         case ACPI_TYPE_INTEGER:
 180
 181                                 obj_desc->integer.value = ACPI_TO_INTEGER(val);
 182                                 break;
 183
 184                         case ACPI_TYPE_STRING:
 185
 186                                 /* Build an object around the static string */
 187
 188                                 obj_desc->string.length = (u32)strlen(val);
 189                                 obj_desc->string.pointer = val;
 190                                 obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
 191                                 break;
 192
 193                         case ACPI_TYPE_MUTEX:
 194
 195                                 obj_desc->mutex.node = new_node;
 196                                 obj_desc->mutex.sync_level =
 197                                     (u8) (ACPI_TO_INTEGER(val) - 1);
 198
 199                                 /* Create a mutex */
 200
 201                                 status =
 202                                     acpi_os_create_mutex(&obj_desc->mutex.
 203                                                          os_mutex);
 204                                 if (ACPI_FAILURE(status)) {
 205                                         acpi_ut_remove_reference(obj_desc);
 206                                         goto unlock_and_exit;
 207                                 }
 208
 209                                 /* Special case for ACPI Global Lock */
 210
 211                                 if (strcmp(init_val->name, "_GL_") == 0) {
 212                                         acpi_gbl_global_lock_mutex = obj_desc;
 213
 214                                         /* Create additional counting semaphore for global lock */
 215
 216                                         status =
 217                                             acpi_os_create_semaphore(1, 0,
 218                                                                      &acpi_gbl_global_lock_semaphore);
 219                                         if (ACPI_FAILURE(status)) {
 220                                                 acpi_ut_remove_reference
 221                                                     (obj_desc);
 222                                                 goto unlock_and_exit;
 223                                         }
 224                                 }
 225                                 break;
 226
 227                         default:
 228
 229                                 ACPI_ERROR((AE_INFO,
 230                                             "Unsupported initial type value 0x%X",
 231                                             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                                                        obj_desc->common.type);
 241
 242                         /* Remove local reference to the object */
 243
 244                         acpi_ut_remove_reference(obj_desc);
 245                 }
 246         }
 247
 248 unlock_and_exit:
 249         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 250
 251         /* Save a handle to "_GPE", it is always present */
 252
 253         if (ACPI_SUCCESS(status)) {
 254                 status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
 255                                           &acpi_gbl_fadt_gpe_device);
 256         }
 257
 258         return_ACPI_STATUS(status);
 259 }
 260
 261 /*******************************************************************************
 262  *
 263  * FUNCTION:    acpi_ns_lookup
 264  *
 265  * PARAMETERS:  scope_info      - Current scope info block
 266  *              pathname        - Search pathname, in internal format
 267  *                                (as represented in the AML stream)
 268  *              type            - Type associated with name
 269  *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
 270  *              flags           - Flags describing the search restrictions
 271  *              walk_state      - Current state of the walk
 272  *              return_node     - Where the Node is placed (if found
 273  *                                or created successfully)
 274  *
 275  * RETURN:      Status
 276  *
 277  * DESCRIPTION: Find or enter the passed name in the name space.
 278  *              Log an error if name not found in Exec mode.
 279  *
 280  * MUTEX:       Assumes namespace is locked.
 281  *
 282  ******************************************************************************/
 283
 284 acpi_status
 285 acpi_ns_lookup(union acpi_generic_state *scope_info,
 286                char *pathname,
 287                acpi_object_type type,
 288                acpi_interpreter_mode interpreter_mode,
 289                u32 flags,
 290                struct acpi_walk_state *walk_state,
 291                struct acpi_namespace_node **return_node)
 292 {
 293         acpi_status status;
 294         char *path = pathname;
 295         char *external_path;
 296         struct acpi_namespace_node *prefix_node;
 297         struct acpi_namespace_node *current_node = NULL;
 298         struct acpi_namespace_node *this_node = NULL;
 299         u32 num_segments;
 300         u32 num_carats;
 301         acpi_name simple_name;
 302         acpi_object_type type_to_check_for;
 303         acpi_object_type this_search_type;
 304         u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
 305         u32 local_flags;
 306
 307         ACPI_FUNCTION_TRACE(ns_lookup);
 308
 309         if (!return_node) {
 310                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 311         }
 312
 313         local_flags = flags &
 314             ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
 315               ACPI_NS_SEARCH_PARENT);
 316         *return_node = ACPI_ENTRY_NOT_FOUND;
 317         acpi_gbl_ns_lookup_count++;
 318
 319         if (!acpi_gbl_root_node) {
 320                 return_ACPI_STATUS(AE_NO_NAMESPACE);
 321         }
 322
 323         /* Get the prefix scope. A null scope means use the root scope */
 324
 325         if ((!scope_info) || (!scope_info->scope.node)) {
 326                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 327                                   "Null scope prefix, using root node (%p)\n",
 328                                   acpi_gbl_root_node));
 329
 330                 prefix_node = acpi_gbl_root_node;
 331         } else {
 332                 prefix_node = scope_info->scope.node;
 333                 if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
 334                     ACPI_DESC_TYPE_NAMED) {
 335                         ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
 336                                     prefix_node,
 337                                     acpi_ut_get_descriptor_name(prefix_node)));
 338                         return_ACPI_STATUS(AE_AML_INTERNAL);
 339                 }
 340
 341                 if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
 342                         /*
 343                          * This node might not be a actual "scope" node (such as a
 344                          * Device/Method, etc.)  It could be a Package or other object
 345                          * node. Backup up the tree to find the containing scope node.
 346                          */
 347                         while (!acpi_ns_opens_scope(prefix_node->type) &&
 348                                prefix_node->type != ACPI_TYPE_ANY) {
 349                                 prefix_node = prefix_node->parent;
 350                         }
 351                 }
 352         }
 353
 354         /* Save type. TBD: may be no longer necessary */
 355
 356         type_to_check_for = type;
 357
 358         /*
 359          * Begin examination of the actual pathname
 360          */
 361         if (!pathname) {
 362
 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
 388                         /* Pathname is fully qualified, start from the root */
 389
 390                         this_node = acpi_gbl_root_node;
 391                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 392
 393                         /* Point to name segment part */
 394
 395                         path++;
 396
 397                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 398                                           "Path is absolute from root [%p]\n",
 399                                           this_node));
 400                 } else {
 401                         /* Pathname is relative to current scope, start there */
 402
 403                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 404                                           "Searching relative to prefix scope [%4.4s] (%p)\n",
 405                                           acpi_ut_get_node_name(prefix_node),
 406                                           prefix_node));
 407
 408                         /*
 409                          * Handle multiple Parent Prefixes (carat) by just getting
 410                          * the parent node for each prefix instance.
 411                          */
 412                         this_node = prefix_node;
 413                         num_carats = 0;
 414                         while (*path == (u8) AML_PARENT_PREFIX) {
 415
 416                                 /* Name is fully qualified, no search rules apply */
 417
 418                                 search_parent_flag = ACPI_NS_NO_UPSEARCH;
 419
 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 = this_node->parent;
 430                                 if (!this_node) {
 431                                         /*
 432                                          * Current scope has no parent scope. Externalize
 433                                          * the internal path for error message.
 434                                          */
 435                                         status =
 436                                             acpi_ns_externalize_name
 437                                             (ACPI_UINT32_MAX, pathname, NULL,
 438                                              &external_path);
 439                                         if (ACPI_SUCCESS(status)) {
 440                                                 ACPI_ERROR((AE_INFO,
 441                                                             "%s: Path has too many parent prefixes (^)",
 442                                                             external_path));
 443
 444                                                 ACPI_FREE(external_path);
 445                                         }
 446
 447                                         return_ACPI_STATUS(AE_NOT_FOUND);
 448                                 }
 449                         }
 450
 451                         if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
 452                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 453                                                   "Search scope is [%4.4s], path has %u carat(s)\n",
 454                                                   acpi_ut_get_node_name
 455                                                   (this_node), num_carats));
 456                         }
 457                 }
 458
 459                 /*
 460                  * Determine the number of ACPI name segments in this pathname.
 461                  *
 462                  * The segment part consists of either:
 463                  *  - A Null name segment (0)
 464                  *  - A dual_name_prefix followed by two 4-byte name segments
 465                  *  - A multi_name_prefix followed by a byte indicating the
 466                  *      number of segments and the segments themselves.
 467                  *  - A single 4-byte name segment
 468                  *
 469                  * Examine the name prefix opcode, if any, to determine the number of
 470                  * segments.
 471                  */
 472                 switch (*path) {
 473                 case 0:
 474                         /*
 475                          * Null name after a root or parent prefixes. We already
 476                          * have the correct target node and there are no name segments.
 477                          */
 478                         num_segments = 0;
 479                         type = this_node->type;
 480
 481                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 482                                           "Prefix-only Pathname (Zero name segments), Flags=%X\n",
 483                                           flags));
 484                         break;
 485
 486                 case AML_DUAL_NAME_PREFIX:
 487
 488                         /* More than one name_seg, search rules do not apply */
 489
 490                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 491
 492                         /* Two segments, point to first name segment */
 493
 494                         num_segments = 2;
 495                         path++;
 496
 497                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 498                                           "Dual Pathname (2 segments, Flags=%X)\n",
 499                                           flags));
 500                         break;
 501
 502                 case AML_MULTI_NAME_PREFIX:
 503
 504                         /* More than one name_seg, search rules do not apply */
 505
 506                         search_parent_flag = ACPI_NS_NO_UPSEARCH;
 507
 508                         /* Extract segment count, point to first name segment */
 509
 510                         path++;
 511                         num_segments = (u32) (u8) * path;
 512                         path++;
 513
 514                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 515                                           "Multi Pathname (%u Segments, Flags=%X)\n",
 516                                           num_segments, flags));
 517                         break;
 518
 519                 default:
 520                         /*
 521                          * Not a Null name, no Dual or Multi prefix, hence there is
 522                          * only one name segment and Pathname is already pointing to it.
 523                          */
 524                         num_segments = 1;
 525
 526                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 527                                           "Simple Pathname (1 segment, Flags=%X)\n",
 528                                           flags));
 529                         break;
 530                 }
 531
 532                 ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
 533         }
 534
 535         /*
 536          * Search namespace for each segment of the name. Loop through and
 537          * verify (or add to the namespace) each name segment.
 538          *
 539          * The object type is significant only at the last name
 540          * segment. (We don't care about the types along the path, only
 541          * the type of the final target object.)
 542          */
 543         this_search_type = ACPI_TYPE_ANY;
 544         current_node = this_node;
 545         while (num_segments && current_node) {
 546                 num_segments--;
 547                 if (!num_segments) {
 548
 549                         /* This is the last segment, enable typechecking */
 550
 551                         this_search_type = type;
 552
 553                         /*
 554                          * Only allow automatic parent search (search rules) if the caller
 555                          * requested it AND we have a single, non-fully-qualified name_seg
 556                          */
 557                         if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
 558                             (flags & ACPI_NS_SEARCH_PARENT)) {
 559                                 local_flags |= ACPI_NS_SEARCH_PARENT;
 560                         }
 561
 562                         /* Set error flag according to caller */
 563
 564                         if (flags & ACPI_NS_ERROR_IF_FOUND) {
 565                                 local_flags |= ACPI_NS_ERROR_IF_FOUND;
 566                         }
 567
 568                         /* Set override flag according to caller */
 569
 570                         if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
 571                                 local_flags |= ACPI_NS_OVERRIDE_IF_FOUND;
 572                         }
 573                 }
 574
 575                 /* Extract one ACPI name from the front of the pathname */
 576
 577                 ACPI_MOVE_32_TO_32(&simple_name, path);
 578
 579                 /* Try to find the single (4 character) ACPI name */
 580
 581                 status =
 582                     acpi_ns_search_and_enter(simple_name, walk_state,
 583                                              current_node, interpreter_mode,
 584                                              this_search_type, local_flags,
 585                                              &this_node);
 586                 if (ACPI_FAILURE(status)) {
 587                         if (status == AE_NOT_FOUND) {
 588
 589                                 /* Name not found in ACPI namespace */
 590
 591                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 592                                                   "Name [%4.4s] not found in scope [%4.4s] %p\n",
 593                                                   (char *)&simple_name,
 594                                                   (char *)&current_node->name,
 595                                                   current_node));
 596                         }
 597 #ifdef ACPI_ASL_COMPILER
 598                         /*
 599                          * If this ACPI name already exists within the namespace as an
 600                          * external declaration, then mark the external as a conflicting
 601                          * declaration and proceed to process the current node as if it did
 602                          * not exist in the namespace. If this node is not processed as
 603                          * normal, then it could cause improper namespace resolution
 604                          * by failing to open a new scope.
 605                          */
 606                         if (acpi_gbl_disasm_flag &&
 607                             (status == AE_ALREADY_EXISTS) &&
 608                             ((this_node->flags & ANOBJ_IS_EXTERNAL) ||
 609                              (walk_state
 610                               && walk_state->opcode == AML_EXTERNAL_OP))) {
 611                                 this_node->flags &= ~ANOBJ_IS_EXTERNAL;
 612                                 this_node->type = (u8)this_search_type;
 613                                 if (walk_state->opcode != AML_EXTERNAL_OP) {
 614                                         acpi_dm_mark_external_conflict
 615                                             (this_node);
 616                                 }
 617                                 break;
 618                         }
 619 #endif
 620
 621                         *return_node = this_node;
 622                         return_ACPI_STATUS(status);
 623                 }
 624
 625                 /* More segments to follow? */
 626
 627                 if (num_segments > 0) {
 628                         /*
 629                          * If we have an alias to an object that opens a scope (such as a
 630                          * device or processor), we need to dereference the alias here so
 631                          * that we can access any children of the original node (via the
 632                          * remaining segments).
 633                          */
 634                         if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
 635                                 if (!this_node->object) {
 636                                         return_ACPI_STATUS(AE_NOT_EXIST);
 637                                 }
 638
 639                                 if (acpi_ns_opens_scope
 640                                     (((struct acpi_namespace_node *)
 641                                       this_node->object)->type)) {
 642                                         this_node =
 643                                             (struct acpi_namespace_node *)
 644                                             this_node->object;
 645                                 }
 646                         }
 647                 }
 648
 649                 /* Special handling for the last segment (num_segments == 0) */
 650
 651                 else {
 652 #ifdef ACPI_ASL_COMPILER
 653                         if (!acpi_gbl_disasm_flag
 654                             && (this_node->flags & ANOBJ_IS_EXTERNAL)) {
 655                                 this_node->flags &= ~IMPLICIT_EXTERNAL;
 656                         }
 657 #endif
 658
 659                         /*
 660                          * Sanity typecheck of the target object:
 661                          *
 662                          * If 1) This is the last segment (num_segments == 0)
 663                          *    2) And we are looking for a specific type
 664                          *       (Not checking for TYPE_ANY)
 665                          *    3) Which is not an alias
 666                          *    4) Which is not a local type (TYPE_SCOPE)
 667                          *    5) And the type of target object is known (not TYPE_ANY)
 668                          *    6) And target object does not match what we are looking for
 669                          *
 670                          * Then we have a type mismatch. Just warn and ignore it.
 671                          */
 672                         if ((type_to_check_for != ACPI_TYPE_ANY) &&
 673                             (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
 674                             (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
 675                             && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
 676                             && (this_node->type != ACPI_TYPE_ANY)
 677                             && (this_node->type != type_to_check_for)) {
 678
 679                                 /* Complain about a type mismatch */
 680
 681                                 ACPI_WARNING((AE_INFO,
 682                                               "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
 683                                               ACPI_CAST_PTR(char, &simple_name),
 684                                               acpi_ut_get_type_name(this_node->
 685                                                                     type),
 686                                               acpi_ut_get_type_name
 687                                               (type_to_check_for)));
 688                         }
 689
 690                         /*
 691                          * If this is the last name segment and we are not looking for a
 692                          * specific type, but the type of found object is known, use that
 693                          * type to (later) see if it opens a scope.
 694                          */
 695                         if (type == ACPI_TYPE_ANY) {
 696                                 type = this_node->type;
 697                         }
 698                 }
 699
 700                 /* Point to next name segment and make this node current */
 701
 702                 path += ACPI_NAME_SIZE;
 703                 current_node = this_node;
 704         }
 705
 706         /* Always check if we need to open a new scope */
 707
 708         if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
 709                 /*
 710                  * If entry is a type which opens a scope, push the new scope on the
 711                  * scope stack.
 712                  */
 713                 if (acpi_ns_opens_scope(type)) {
 714                         status =
 715                             acpi_ds_scope_stack_push(this_node, type,
 716                                                      walk_state);
 717                         if (ACPI_FAILURE(status)) {
 718                                 return_ACPI_STATUS(status);
 719                         }
 720                 }
 721         }
 722
 723         *return_node = this_node;
 724         return_ACPI_STATUS(AE_OK);
 725 }