drivers/acpi/acpica/nsutils.c

   1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2 /******************************************************************************
   3  *
   4  * Module Name: nsutils - Utilities for accessing ACPI namespace, accessing
   5  *                        parents and siblings and Scope manipulation
   6  *
   7  * Copyright (C) 2000 - 2018, Intel Corp.
   8  *
   9  *****************************************************************************/
  10
  11 #include <acpi/acpi.h>
  12 #include "accommon.h"
  13 #include "acnamesp.h"
  14 #include "amlcode.h"
  15
  16 #define _COMPONENT          ACPI_NAMESPACE
  17 ACPI_MODULE_NAME("nsutils")
  18
  19 /* Local prototypes */
  20 #ifdef ACPI_OBSOLETE_FUNCTIONS
  21 acpi_name acpi_ns_find_parent_name(struct acpi_namespace_node *node_to_search);
  22 #endif
  23
  24 /*******************************************************************************
  25  *
  26  * FUNCTION:    acpi_ns_print_node_pathname
  27  *
  28  * PARAMETERS:  node            - Object
  29  *              message         - Prefix message
  30  *
  31  * DESCRIPTION: Print an object's full namespace pathname
  32  *              Manages allocation/freeing of a pathname buffer
  33  *
  34  ******************************************************************************/
  35
  36 void
  37 acpi_ns_print_node_pathname(struct acpi_namespace_node *node,
  38                             const char *message)
  39 {
  40         struct acpi_buffer buffer;
  41         acpi_status status;
  42
  43         if (!node) {
  44                 acpi_os_printf("[NULL NAME]");
  45                 return;
  46         }
  47
  48         /* Convert handle to full pathname and print it (with supplied message) */
  49
  50         buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
  51
  52         status = acpi_ns_handle_to_pathname(node, &buffer, TRUE);
  53         if (ACPI_SUCCESS(status)) {
  54                 if (message) {
  55                         acpi_os_printf("%s ", message);
  56                 }
  57
  58                 acpi_os_printf("%s", (char *)buffer.pointer);
  59                 ACPI_FREE(buffer.pointer);
  60         }
  61 }
  62
  63 /*******************************************************************************
  64  *
  65  * FUNCTION:    acpi_ns_get_type
  66  *
  67  * PARAMETERS:  node        - Parent Node to be examined
  68  *
  69  * RETURN:      Type field from Node whose handle is passed
  70  *
  71  * DESCRIPTION: Return the type of a Namespace node
  72  *
  73  ******************************************************************************/
  74
  75 acpi_object_type acpi_ns_get_type(struct acpi_namespace_node * node)
  76 {
  77         ACPI_FUNCTION_TRACE(ns_get_type);
  78
  79         if (!node) {
  80                 ACPI_WARNING((AE_INFO, "Null Node parameter"));
  81                 return_UINT8(ACPI_TYPE_ANY);
  82         }
  83
  84         return_UINT8(node->type);
  85 }
  86
  87 /*******************************************************************************
  88  *
  89  * FUNCTION:    acpi_ns_local
  90  *
  91  * PARAMETERS:  type        - A namespace object type
  92  *
  93  * RETURN:      LOCAL if names must be found locally in objects of the
  94  *              passed type, 0 if enclosing scopes should be searched
  95  *
  96  * DESCRIPTION: Returns scope rule for the given object type.
  97  *
  98  ******************************************************************************/
  99
 100 u32 acpi_ns_local(acpi_object_type type)
 101 {
 102         ACPI_FUNCTION_TRACE(ns_local);
 103
 104         if (!acpi_ut_valid_object_type(type)) {
 105
 106                 /* Type code out of range  */
 107
 108                 ACPI_WARNING((AE_INFO, "Invalid Object Type 0x%X", type));
 109                 return_UINT32(ACPI_NS_NORMAL);
 110         }
 111
 112         return_UINT32(acpi_gbl_ns_properties[type] & ACPI_NS_LOCAL);
 113 }
 114
 115 /*******************************************************************************
 116  *
 117  * FUNCTION:    acpi_ns_get_internal_name_length
 118  *
 119  * PARAMETERS:  info            - Info struct initialized with the
 120  *                                external name pointer.
 121  *
 122  * RETURN:      None
 123  *
 124  * DESCRIPTION: Calculate the length of the internal (AML) namestring
 125  *              corresponding to the external (ASL) namestring.
 126  *
 127  ******************************************************************************/
 128
 129 void acpi_ns_get_internal_name_length(struct acpi_namestring_info *info)
 130 {
 131         const char *next_external_char;
 132         u32 i;
 133
 134         ACPI_FUNCTION_ENTRY();
 135
 136         next_external_char = info->external_name;
 137         info->num_carats = 0;
 138         info->num_segments = 0;
 139         info->fully_qualified = FALSE;
 140
 141         /*
 142          * For the internal name, the required length is 4 bytes per segment,
 143          * plus 1 each for root_prefix, multi_name_prefix_op, segment count,
 144          * trailing null (which is not really needed, but no there's harm in
 145          * putting it there)
 146          *
 147          * strlen() + 1 covers the first name_seg, which has no path separator
 148          */
 149         if (ACPI_IS_ROOT_PREFIX(*next_external_char)) {
 150                 info->fully_qualified = TRUE;
 151                 next_external_char++;
 152
 153                 /* Skip redundant root_prefix, like \\_SB.PCI0.SBRG.EC0 */
 154
 155                 while (ACPI_IS_ROOT_PREFIX(*next_external_char)) {
 156                         next_external_char++;
 157                 }
 158         } else {
 159                 /* Handle Carat prefixes */
 160
 161                 while (ACPI_IS_PARENT_PREFIX(*next_external_char)) {
 162                         info->num_carats++;
 163                         next_external_char++;
 164                 }
 165         }
 166
 167         /*
 168          * Determine the number of ACPI name "segments" by counting the number of
 169          * path separators within the string. Start with one segment since the
 170          * segment count is [(# separators) + 1], and zero separators is ok.
 171          */
 172         if (*next_external_char) {
 173                 info->num_segments = 1;
 174                 for (i = 0; next_external_char[i]; i++) {
 175                         if (ACPI_IS_PATH_SEPARATOR(next_external_char[i])) {
 176                                 info->num_segments++;
 177                         }
 178                 }
 179         }
 180
 181         info->length = (ACPI_NAME_SIZE * info->num_segments) +
 182             4 + info->num_carats;
 183
 184         info->next_external_char = next_external_char;
 185 }
 186
 187 /*******************************************************************************
 188  *
 189  * FUNCTION:    acpi_ns_build_internal_name
 190  *
 191  * PARAMETERS:  info            - Info struct fully initialized
 192  *
 193  * RETURN:      Status
 194  *
 195  * DESCRIPTION: Construct the internal (AML) namestring
 196  *              corresponding to the external (ASL) namestring.
 197  *
 198  ******************************************************************************/
 199
 200 acpi_status acpi_ns_build_internal_name(struct acpi_namestring_info *info)
 201 {
 202         u32 num_segments = info->num_segments;
 203         char *internal_name = info->internal_name;
 204         const char *external_name = info->next_external_char;
 205         char *result = NULL;
 206         u32 i;
 207
 208         ACPI_FUNCTION_TRACE(ns_build_internal_name);
 209
 210         /* Setup the correct prefixes, counts, and pointers */
 211
 212         if (info->fully_qualified) {
 213                 internal_name[0] = AML_ROOT_PREFIX;
 214
 215                 if (num_segments <= 1) {
 216                         result = &internal_name[1];
 217                 } else if (num_segments == 2) {
 218                         internal_name[1] = AML_DUAL_NAME_PREFIX;
 219                         result = &internal_name[2];
 220                 } else {
 221                         internal_name[1] = AML_MULTI_NAME_PREFIX;
 222                         internal_name[2] = (char)num_segments;
 223                         result = &internal_name[3];
 224                 }
 225         } else {
 226                 /*
 227                  * Not fully qualified.
 228                  * Handle Carats first, then append the name segments
 229                  */
 230                 i = 0;
 231                 if (info->num_carats) {
 232                         for (i = 0; i < info->num_carats; i++) {
 233                                 internal_name[i] = AML_PARENT_PREFIX;
 234                         }
 235                 }
 236
 237                 if (num_segments <= 1) {
 238                         result = &internal_name[i];
 239                 } else if (num_segments == 2) {
 240                         internal_name[i] = AML_DUAL_NAME_PREFIX;
 241                         result = &internal_name[(acpi_size)i + 1];
 242                 } else {
 243                         internal_name[i] = AML_MULTI_NAME_PREFIX;
 244                         internal_name[(acpi_size)i + 1] = (char)num_segments;
 245                         result = &internal_name[(acpi_size)i + 2];
 246                 }
 247         }
 248
 249         /* Build the name (minus path separators) */
 250
 251         for (; num_segments; num_segments--) {
 252                 for (i = 0; i < ACPI_NAME_SIZE; i++) {
 253                         if (ACPI_IS_PATH_SEPARATOR(*external_name) ||
 254                             (*external_name == 0)) {
 255
 256                                 /* Pad the segment with underscore(s) if segment is short */
 257
 258                                 result[i] = '_';
 259                         } else {
 260                                 /* Convert the character to uppercase and save it */
 261
 262                                 result[i] = (char)toupper((int)*external_name);
 263                                 external_name++;
 264                         }
 265                 }
 266
 267                 /* Now we must have a path separator, or the pathname is bad */
 268
 269                 if (!ACPI_IS_PATH_SEPARATOR(*external_name) &&
 270                     (*external_name != 0)) {
 271                         return_ACPI_STATUS(AE_BAD_PATHNAME);
 272                 }
 273
 274                 /* Move on the next segment */
 275
 276                 external_name++;
 277                 result += ACPI_NAME_SIZE;
 278         }
 279
 280         /* Terminate the string */
 281
 282         *result = 0;
 283
 284         if (info->fully_qualified) {
 285                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 286                                   "Returning [%p] (abs) \"\\%s\"\n",
 287                                   internal_name, internal_name));
 288         } else {
 289                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Returning [%p] (rel) \"%s\"\n",
 290                                   internal_name, internal_name));
 291         }
 292
 293         return_ACPI_STATUS(AE_OK);
 294 }
 295
 296 /*******************************************************************************
 297  *
 298  * FUNCTION:    acpi_ns_internalize_name
 299  *
 300  * PARAMETERS:  *external_name          - External representation of name
 301  *              **Converted name        - Where to return the resulting
 302  *                                        internal represention of the name
 303  *
 304  * RETURN:      Status
 305  *
 306  * DESCRIPTION: Convert an external representation (e.g. "\_PR_.CPU0")
 307  *              to internal form (e.g. 5c 2f 02 5f 50 52 5f 43 50 55 30)
 308  *
 309  *******************************************************************************/
 310
 311 acpi_status
 312 acpi_ns_internalize_name(const char *external_name, char **converted_name)
 313 {
 314         char *internal_name;
 315         struct acpi_namestring_info info;
 316         acpi_status status;
 317
 318         ACPI_FUNCTION_TRACE(ns_internalize_name);
 319
 320         if ((!external_name) || (*external_name == 0) || (!converted_name)) {
 321                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 322         }
 323
 324         /* Get the length of the new internal name */
 325
 326         info.external_name = external_name;
 327         acpi_ns_get_internal_name_length(&info);
 328
 329         /* We need a segment to store the internal  name */
 330
 331         internal_name = ACPI_ALLOCATE_ZEROED(info.length);
 332         if (!internal_name) {
 333                 return_ACPI_STATUS(AE_NO_MEMORY);
 334         }
 335
 336         /* Build the name */
 337
 338         info.internal_name = internal_name;
 339         status = acpi_ns_build_internal_name(&info);
 340         if (ACPI_FAILURE(status)) {
 341                 ACPI_FREE(internal_name);
 342                 return_ACPI_STATUS(status);
 343         }
 344
 345         *converted_name = internal_name;
 346         return_ACPI_STATUS(AE_OK);
 347 }
 348
 349 /*******************************************************************************
 350  *
 351  * FUNCTION:    acpi_ns_externalize_name
 352  *
 353  * PARAMETERS:  internal_name_length - Lenth of the internal name below
 354  *              internal_name       - Internal representation of name
 355  *              converted_name_length - Where the length is returned
 356  *              converted_name      - Where the resulting external name
 357  *                                    is returned
 358  *
 359  * RETURN:      Status
 360  *
 361  * DESCRIPTION: Convert internal name (e.g. 5c 2f 02 5f 50 52 5f 43 50 55 30)
 362  *              to its external (printable) form (e.g. "\_PR_.CPU0")
 363  *
 364  ******************************************************************************/
 365
 366 acpi_status
 367 acpi_ns_externalize_name(u32 internal_name_length,
 368                          const char *internal_name,
 369                          u32 * converted_name_length, char **converted_name)
 370 {
 371         u32 names_index = 0;
 372         u32 num_segments = 0;
 373         u32 required_length;
 374         u32 prefix_length = 0;
 375         u32 i = 0;
 376         u32 j = 0;
 377
 378         ACPI_FUNCTION_TRACE(ns_externalize_name);
 379
 380         if (!internal_name_length || !internal_name || !converted_name) {
 381                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 382         }
 383
 384         /* Check for a prefix (one '\' | one or more '^') */
 385
 386         switch (internal_name[0]) {
 387         case AML_ROOT_PREFIX:
 388
 389                 prefix_length = 1;
 390                 break;
 391
 392         case AML_PARENT_PREFIX:
 393
 394                 for (i = 0; i < internal_name_length; i++) {
 395                         if (ACPI_IS_PARENT_PREFIX(internal_name[i])) {
 396                                 prefix_length = i + 1;
 397                         } else {
 398                                 break;
 399                         }
 400                 }
 401
 402                 if (i == internal_name_length) {
 403                         prefix_length = i;
 404                 }
 405
 406                 break;
 407
 408         default:
 409
 410                 break;
 411         }
 412
 413         /*
 414          * Check for object names. Note that there could be 0-255 of these
 415          * 4-byte elements.
 416          */
 417         if (prefix_length < internal_name_length) {
 418                 switch (internal_name[prefix_length]) {
 419                 case AML_MULTI_NAME_PREFIX:
 420
 421                         /* <count> 4-byte names */
 422
 423                         names_index = prefix_length + 2;
 424                         num_segments = (u8)
 425                             internal_name[(acpi_size)prefix_length + 1];
 426                         break;
 427
 428                 case AML_DUAL_NAME_PREFIX:
 429
 430                         /* Two 4-byte names */
 431
 432                         names_index = prefix_length + 1;
 433                         num_segments = 2;
 434                         break;
 435
 436                 case 0:
 437
 438                         /* null_name */
 439
 440                         names_index = 0;
 441                         num_segments = 0;
 442                         break;
 443
 444                 default:
 445
 446                         /* one 4-byte name */
 447
 448                         names_index = prefix_length;
 449                         num_segments = 1;
 450                         break;
 451                 }
 452         }
 453
 454         /*
 455          * Calculate the length of converted_name, which equals the length
 456          * of the prefix, length of all object names, length of any required
 457          * punctuation ('.') between object names, plus the NULL terminator.
 458          */
 459         required_length = prefix_length + (4 * num_segments) +
 460             ((num_segments > 0) ? (num_segments - 1) : 0) + 1;
 461
 462         /*
 463          * Check to see if we're still in bounds. If not, there's a problem
 464          * with internal_name (invalid format).
 465          */
 466         if (required_length > internal_name_length) {
 467                 ACPI_ERROR((AE_INFO, "Invalid internal name"));
 468                 return_ACPI_STATUS(AE_BAD_PATHNAME);
 469         }
 470
 471         /* Build the converted_name */
 472
 473         *converted_name = ACPI_ALLOCATE_ZEROED(required_length);
 474         if (!(*converted_name)) {
 475                 return_ACPI_STATUS(AE_NO_MEMORY);
 476         }
 477
 478         j = 0;
 479
 480         for (i = 0; i < prefix_length; i++) {
 481                 (*converted_name)[j++] = internal_name[i];
 482         }
 483
 484         if (num_segments > 0) {
 485                 for (i = 0; i < num_segments; i++) {
 486                         if (i > 0) {
 487                                 (*converted_name)[j++] = '.';
 488                         }
 489
 490                         /* Copy and validate the 4-char name segment */
 491
 492                         ACPI_MOVE_NAME(&(*converted_name)[j],
 493                                        &internal_name[names_index]);
 494                         acpi_ut_repair_name(&(*converted_name)[j]);
 495
 496                         j += ACPI_NAME_SIZE;
 497                         names_index += ACPI_NAME_SIZE;
 498                 }
 499         }
 500
 501         if (converted_name_length) {
 502                 *converted_name_length = (u32) required_length;
 503         }
 504
 505         return_ACPI_STATUS(AE_OK);
 506 }
 507
 508 /*******************************************************************************
 509  *
 510  * FUNCTION:    acpi_ns_validate_handle
 511  *
 512  * PARAMETERS:  handle          - Handle to be validated and typecast to a
 513  *                                namespace node.
 514  *
 515  * RETURN:      A pointer to a namespace node
 516  *
 517  * DESCRIPTION: Convert a namespace handle to a namespace node. Handles special
 518  *              cases for the root node.
 519  *
 520  * NOTE: Real integer handles would allow for more verification
 521  *       and keep all pointers within this subsystem - however this introduces
 522  *       more overhead and has not been necessary to this point. Drivers
 523  *       holding handles are typically notified before a node becomes invalid
 524  *       due to a table unload.
 525  *
 526  ******************************************************************************/
 527
 528 struct acpi_namespace_node *acpi_ns_validate_handle(acpi_handle handle)
 529 {
 530
 531         ACPI_FUNCTION_ENTRY();
 532
 533         /* Parameter validation */
 534
 535         if ((!handle) || (handle == ACPI_ROOT_OBJECT)) {
 536                 return (acpi_gbl_root_node);
 537         }
 538
 539         /* We can at least attempt to verify the handle */
 540
 541         if (ACPI_GET_DESCRIPTOR_TYPE(handle) != ACPI_DESC_TYPE_NAMED) {
 542                 return (NULL);
 543         }
 544
 545         return (ACPI_CAST_PTR(struct acpi_namespace_node, handle));
 546 }
 547
 548 /*******************************************************************************
 549  *
 550  * FUNCTION:    acpi_ns_terminate
 551  *
 552  * PARAMETERS:  none
 553  *
 554  * RETURN:      none
 555  *
 556  * DESCRIPTION: free memory allocated for namespace and ACPI table storage.
 557  *
 558  ******************************************************************************/
 559
 560 void acpi_ns_terminate(void)
 561 {
 562         acpi_status status;
 563         union acpi_operand_object *prev;
 564         union acpi_operand_object *next;
 565
 566         ACPI_FUNCTION_TRACE(ns_terminate);
 567
 568         /* Delete any module-level code blocks */
 569
 570         next = acpi_gbl_module_code_list;
 571         while (next) {
 572                 prev = next;
 573                 next = next->method.mutex;
 574                 prev->method.mutex = NULL;      /* Clear the Mutex (cheated) field */
 575                 acpi_ut_remove_reference(prev);
 576         }
 577
 578         /*
 579          * Free the entire namespace -- all nodes and all objects
 580          * attached to the nodes
 581          */
 582         acpi_ns_delete_namespace_subtree(acpi_gbl_root_node);
 583
 584         /* Delete any objects attached to the root node */
 585
 586         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 587         if (ACPI_FAILURE(status)) {
 588                 return_VOID;
 589         }
 590
 591         acpi_ns_delete_node(acpi_gbl_root_node);
 592         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 593
 594         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Namespace freed\n"));
 595         return_VOID;
 596 }
 597
 598 /*******************************************************************************
 599  *
 600  * FUNCTION:    acpi_ns_opens_scope
 601  *
 602  * PARAMETERS:  type        - A valid namespace type
 603  *
 604  * RETURN:      NEWSCOPE if the passed type "opens a name scope" according
 605  *              to the ACPI specification, else 0
 606  *
 607  ******************************************************************************/
 608
 609 u32 acpi_ns_opens_scope(acpi_object_type type)
 610 {
 611         ACPI_FUNCTION_ENTRY();
 612
 613         if (type > ACPI_TYPE_LOCAL_MAX) {
 614
 615                 /* type code out of range  */
 616
 617                 ACPI_WARNING((AE_INFO, "Invalid Object Type 0x%X", type));
 618                 return (ACPI_NS_NORMAL);
 619         }
 620
 621         return (((u32)acpi_gbl_ns_properties[type]) & ACPI_NS_NEWSCOPE);
 622 }
 623
 624 /*******************************************************************************
 625  *
 626  * FUNCTION:    acpi_ns_get_node_unlocked
 627  *
 628  * PARAMETERS:  *pathname   - Name to be found, in external (ASL) format. The
 629  *                            \ (backslash) and ^ (carat) prefixes, and the
 630  *                            . (period) to separate segments are supported.
 631  *              prefix_node  - Root of subtree to be searched, or NS_ALL for the
 632  *                            root of the name space. If Name is fully
 633  *                            qualified (first s8 is '\'), the passed value
 634  *                            of Scope will not be accessed.
 635  *              flags       - Used to indicate whether to perform upsearch or
 636  *                            not.
 637  *              return_node - Where the Node is returned
 638  *
 639  * DESCRIPTION: Look up a name relative to a given scope and return the
 640  *              corresponding Node. NOTE: Scope can be null.
 641  *
 642  * MUTEX:       Doesn't locks namespace
 643  *
 644  ******************************************************************************/
 645
 646 acpi_status
 647 acpi_ns_get_node_unlocked(struct acpi_namespace_node *prefix_node,
 648                           const char *pathname,
 649                           u32 flags, struct acpi_namespace_node **return_node)
 650 {
 651         union acpi_generic_state scope_info;
 652         acpi_status status;
 653         char *internal_path;
 654
 655         ACPI_FUNCTION_TRACE_PTR(ns_get_node_unlocked,
 656                                 ACPI_CAST_PTR(char, pathname));
 657
 658         /* Simplest case is a null pathname */
 659
 660         if (!pathname) {
 661                 *return_node = prefix_node;
 662                 if (!prefix_node) {
 663                         *return_node = acpi_gbl_root_node;
 664                 }
 665
 666                 return_ACPI_STATUS(AE_OK);
 667         }
 668
 669         /* Quick check for a reference to the root */
 670
 671         if (ACPI_IS_ROOT_PREFIX(pathname[0]) && (!pathname[1])) {
 672                 *return_node = acpi_gbl_root_node;
 673                 return_ACPI_STATUS(AE_OK);
 674         }
 675
 676         /* Convert path to internal representation */
 677
 678         status = acpi_ns_internalize_name(pathname, &internal_path);
 679         if (ACPI_FAILURE(status)) {
 680                 return_ACPI_STATUS(status);
 681         }
 682
 683         /* Setup lookup scope (search starting point) */
 684
 685         scope_info.scope.node = prefix_node;
 686
 687         /* Lookup the name in the namespace */
 688
 689         status = acpi_ns_lookup(&scope_info, internal_path, ACPI_TYPE_ANY,
 690                                 ACPI_IMODE_EXECUTE,
 691                                 (flags | ACPI_NS_DONT_OPEN_SCOPE), NULL,
 692                                 return_node);
 693         if (ACPI_FAILURE(status)) {
 694                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s, %s\n",
 695                                   pathname, acpi_format_exception(status)));
 696         }
 697
 698         ACPI_FREE(internal_path);
 699         return_ACPI_STATUS(status);
 700 }
 701
 702 /*******************************************************************************
 703  *
 704  * FUNCTION:    acpi_ns_get_node
 705  *
 706  * PARAMETERS:  *pathname   - Name to be found, in external (ASL) format. The
 707  *                            \ (backslash) and ^ (carat) prefixes, and the
 708  *                            . (period) to separate segments are supported.
 709  *              prefix_node  - Root of subtree to be searched, or NS_ALL for the
 710  *                            root of the name space. If Name is fully
 711  *                            qualified (first s8 is '\'), the passed value
 712  *                            of Scope will not be accessed.
 713  *              flags       - Used to indicate whether to perform upsearch or
 714  *                            not.
 715  *              return_node - Where the Node is returned
 716  *
 717  * DESCRIPTION: Look up a name relative to a given scope and return the
 718  *              corresponding Node. NOTE: Scope can be null.
 719  *
 720  * MUTEX:       Locks namespace
 721  *
 722  ******************************************************************************/
 723
 724 acpi_status
 725 acpi_ns_get_node(struct acpi_namespace_node *prefix_node,
 726                  const char *pathname,
 727                  u32 flags, struct acpi_namespace_node **return_node)
 728 {
 729         acpi_status status;
 730
 731         ACPI_FUNCTION_TRACE_PTR(ns_get_node, ACPI_CAST_PTR(char, pathname));
 732
 733         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 734         if (ACPI_FAILURE(status)) {
 735                 return_ACPI_STATUS(status);
 736         }
 737
 738         status = acpi_ns_get_node_unlocked(prefix_node, pathname,
 739                                            flags, return_node);
 740
 741         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 742         return_ACPI_STATUS(status);
 743 }