drivers/acpi/acpica/psparse.c

   1 /******************************************************************************
   2  *
   3  * Module Name: psparse - Parser top level AML parse routines
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2015, 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 /*
  45  * Parse the AML and build an operation tree as most interpreters,
  46  * like Perl, do. Parsing is done by hand rather than with a YACC
  47  * generated parser to tightly constrain stack and dynamic memory
  48  * usage. At the same time, parsing is kept flexible and the code
  49  * fairly compact by parsing based on a list of AML opcode
  50  * templates in aml_op_info[]
  51  */
  52
  53 #include <acpi/acpi.h>
  54 #include "accommon.h"
  55 #include "acparser.h"
  56 #include "acdispat.h"
  57 #include "amlcode.h"
  58 #include "acinterp.h"
  59
  60 #define _COMPONENT          ACPI_PARSER
  61 ACPI_MODULE_NAME("psparse")
  62
  63 /*******************************************************************************
  64  *
  65  * FUNCTION:    acpi_ps_get_opcode_size
  66  *
  67  * PARAMETERS:  opcode          - An AML opcode
  68  *
  69  * RETURN:      Size of the opcode, in bytes (1 or 2)
  70  *
  71  * DESCRIPTION: Get the size of the current opcode.
  72  *
  73  ******************************************************************************/
  74 u32 acpi_ps_get_opcode_size(u32 opcode)
  75 {
  76
  77         /* Extended (2-byte) opcode if > 255 */
  78
  79         if (opcode > 0x00FF) {
  80                 return (2);
  81         }
  82
  83         /* Otherwise, just a single byte opcode */
  84
  85         return (1);
  86 }
  87
  88 /*******************************************************************************
  89  *
  90  * FUNCTION:    acpi_ps_peek_opcode
  91  *
  92  * PARAMETERS:  parser_state        - A parser state object
  93  *
  94  * RETURN:      Next AML opcode
  95  *
  96  * DESCRIPTION: Get next AML opcode (without incrementing AML pointer)
  97  *
  98  ******************************************************************************/
  99
 100 u16 acpi_ps_peek_opcode(struct acpi_parse_state * parser_state)
 101 {
 102         u8 *aml;
 103         u16 opcode;
 104
 105         aml = parser_state->aml;
 106         opcode = (u16) ACPI_GET8(aml);
 107
 108         if (opcode == AML_EXTENDED_OP_PREFIX) {
 109
 110                 /* Extended opcode, get the second opcode byte */
 111
 112                 aml++;
 113                 opcode = (u16) ((opcode << 8) | ACPI_GET8(aml));
 114         }
 115
 116         return (opcode);
 117 }
 118
 119 /*******************************************************************************
 120  *
 121  * FUNCTION:    acpi_ps_complete_this_op
 122  *
 123  * PARAMETERS:  walk_state      - Current State
 124  *              op              - Op to complete
 125  *
 126  * RETURN:      Status
 127  *
 128  * DESCRIPTION: Perform any cleanup at the completion of an Op.
 129  *
 130  ******************************************************************************/
 131
 132 acpi_status
 133 acpi_ps_complete_this_op(struct acpi_walk_state * walk_state,
 134                          union acpi_parse_object * op)
 135 {
 136         union acpi_parse_object *prev;
 137         union acpi_parse_object *next;
 138         const struct acpi_opcode_info *parent_info;
 139         union acpi_parse_object *replacement_op = NULL;
 140         acpi_status status = AE_OK;
 141
 142         ACPI_FUNCTION_TRACE_PTR(ps_complete_this_op, op);
 143
 144         /* Check for null Op, can happen if AML code is corrupt */
 145
 146         if (!op) {
 147                 return_ACPI_STATUS(AE_OK);      /* OK for now */
 148         }
 149
 150         ACPI_DEBUG_PRINT((ACPI_DB_TRACE_POINT,
 151                           "End opcode: %s[0x%p].\n",
 152                           op->common.aml_op_name, op->common.aml));
 153
 154         /* Delete this op and the subtree below it if asked to */
 155
 156         if (((walk_state->parse_flags & ACPI_PARSE_TREE_MASK) !=
 157              ACPI_PARSE_DELETE_TREE)
 158             || (walk_state->op_info->class == AML_CLASS_ARGUMENT)) {
 159                 return_ACPI_STATUS(AE_OK);
 160         }
 161
 162         /* Make sure that we only delete this subtree */
 163
 164         if (op->common.parent) {
 165                 prev = op->common.parent->common.value.arg;
 166                 if (!prev) {
 167
 168                         /* Nothing more to do */
 169
 170                         goto cleanup;
 171                 }
 172
 173                 /*
 174                  * Check if we need to replace the operator and its subtree
 175                  * with a return value op (placeholder op)
 176                  */
 177                 parent_info =
 178                     acpi_ps_get_opcode_info(op->common.parent->common.
 179                                             aml_opcode);
 180
 181                 switch (parent_info->class) {
 182                 case AML_CLASS_CONTROL:
 183
 184                         break;
 185
 186                 case AML_CLASS_CREATE:
 187                         /*
 188                          * These opcodes contain term_arg operands. The current
 189                          * op must be replaced by a placeholder return op
 190                          */
 191                         replacement_op =
 192                             acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
 193                                              op->common.aml);
 194                         if (!replacement_op) {
 195                                 status = AE_NO_MEMORY;
 196                         }
 197                         break;
 198
 199                 case AML_CLASS_NAMED_OBJECT:
 200                         /*
 201                          * These opcodes contain term_arg operands. The current
 202                          * op must be replaced by a placeholder return op
 203                          */
 204                         if ((op->common.parent->common.aml_opcode ==
 205                              AML_REGION_OP)
 206                             || (op->common.parent->common.aml_opcode ==
 207                                 AML_DATA_REGION_OP)
 208                             || (op->common.parent->common.aml_opcode ==
 209                                 AML_BUFFER_OP)
 210                             || (op->common.parent->common.aml_opcode ==
 211                                 AML_PACKAGE_OP)
 212                             || (op->common.parent->common.aml_opcode ==
 213                                 AML_BANK_FIELD_OP)
 214                             || (op->common.parent->common.aml_opcode ==
 215                                 AML_VAR_PACKAGE_OP)) {
 216                                 replacement_op =
 217                                     acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
 218                                                      op->common.aml);
 219                                 if (!replacement_op) {
 220                                         status = AE_NO_MEMORY;
 221                                 }
 222                         } else
 223                             if ((op->common.parent->common.aml_opcode ==
 224                                  AML_NAME_OP)
 225                                 && (walk_state->pass_number <=
 226                                     ACPI_IMODE_LOAD_PASS2)) {
 227                                 if ((op->common.aml_opcode == AML_BUFFER_OP)
 228                                     || (op->common.aml_opcode == AML_PACKAGE_OP)
 229                                     || (op->common.aml_opcode ==
 230                                         AML_VAR_PACKAGE_OP)) {
 231                                         replacement_op =
 232                                             acpi_ps_alloc_op(op->common.
 233                                                              aml_opcode,
 234                                                              op->common.aml);
 235                                         if (!replacement_op) {
 236                                                 status = AE_NO_MEMORY;
 237                                         } else {
 238                                                 replacement_op->named.data =
 239                                                     op->named.data;
 240                                                 replacement_op->named.length =
 241                                                     op->named.length;
 242                                         }
 243                                 }
 244                         }
 245                         break;
 246
 247                 default:
 248
 249                         replacement_op =
 250                             acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
 251                                              op->common.aml);
 252                         if (!replacement_op) {
 253                                 status = AE_NO_MEMORY;
 254                         }
 255                 }
 256
 257                 /* We must unlink this op from the parent tree */
 258
 259                 if (prev == op) {
 260
 261                         /* This op is the first in the list */
 262
 263                         if (replacement_op) {
 264                                 replacement_op->common.parent =
 265                                     op->common.parent;
 266                                 replacement_op->common.value.arg = NULL;
 267                                 replacement_op->common.node = op->common.node;
 268                                 op->common.parent->common.value.arg =
 269                                     replacement_op;
 270                                 replacement_op->common.next = op->common.next;
 271                         } else {
 272                                 op->common.parent->common.value.arg =
 273                                     op->common.next;
 274                         }
 275                 }
 276
 277                 /* Search the parent list */
 278
 279                 else
 280                         while (prev) {
 281
 282                                 /* Traverse all siblings in the parent's argument list */
 283
 284                                 next = prev->common.next;
 285                                 if (next == op) {
 286                                         if (replacement_op) {
 287                                                 replacement_op->common.parent =
 288                                                     op->common.parent;
 289                                                 replacement_op->common.value.
 290                                                     arg = NULL;
 291                                                 replacement_op->common.node =
 292                                                     op->common.node;
 293                                                 prev->common.next =
 294                                                     replacement_op;
 295                                                 replacement_op->common.next =
 296                                                     op->common.next;
 297                                                 next = NULL;
 298                                         } else {
 299                                                 prev->common.next =
 300                                                     op->common.next;
 301                                                 next = NULL;
 302                                         }
 303                                 }
 304                                 prev = next;
 305                         }
 306         }
 307
 308 cleanup:
 309
 310         /* Now we can actually delete the subtree rooted at Op */
 311
 312         acpi_ps_delete_parse_tree(op);
 313         return_ACPI_STATUS(status);
 314 }
 315
 316 /*******************************************************************************
 317  *
 318  * FUNCTION:    acpi_ps_next_parse_state
 319  *
 320  * PARAMETERS:  walk_state          - Current state
 321  *              op                  - Current parse op
 322  *              callback_status     - Status from previous operation
 323  *
 324  * RETURN:      Status
 325  *
 326  * DESCRIPTION: Update the parser state based upon the return exception from
 327  *              the parser callback.
 328  *
 329  ******************************************************************************/
 330
 331 acpi_status
 332 acpi_ps_next_parse_state(struct acpi_walk_state *walk_state,
 333                          union acpi_parse_object *op,
 334                          acpi_status callback_status)
 335 {
 336         struct acpi_parse_state *parser_state = &walk_state->parser_state;
 337         acpi_status status = AE_CTRL_PENDING;
 338
 339         ACPI_FUNCTION_TRACE_PTR(ps_next_parse_state, op);
 340
 341         switch (callback_status) {
 342         case AE_CTRL_TERMINATE:
 343                 /*
 344                  * A control method was terminated via a RETURN statement.
 345                  * The walk of this method is complete.
 346                  */
 347                 parser_state->aml = parser_state->aml_end;
 348                 status = AE_CTRL_TERMINATE;
 349                 break;
 350
 351         case AE_CTRL_BREAK:
 352
 353                 parser_state->aml = walk_state->aml_last_while;
 354                 walk_state->control_state->common.value = FALSE;
 355                 status = AE_CTRL_BREAK;
 356                 break;
 357
 358         case AE_CTRL_CONTINUE:
 359
 360                 parser_state->aml = walk_state->aml_last_while;
 361                 status = AE_CTRL_CONTINUE;
 362                 break;
 363
 364         case AE_CTRL_PENDING:
 365
 366                 parser_state->aml = walk_state->aml_last_while;
 367                 break;
 368
 369 #if 0
 370         case AE_CTRL_SKIP:
 371
 372                 parser_state->aml = parser_state->scope->parse_scope.pkg_end;
 373                 status = AE_OK;
 374                 break;
 375 #endif
 376
 377         case AE_CTRL_TRUE:
 378                 /*
 379                  * Predicate of an IF was true, and we are at the matching ELSE.
 380                  * Just close out this package
 381                  */
 382                 parser_state->aml = acpi_ps_get_next_package_end(parser_state);
 383                 status = AE_CTRL_PENDING;
 384                 break;
 385
 386         case AE_CTRL_FALSE:
 387                 /*
 388                  * Either an IF/WHILE Predicate was false or we encountered a BREAK
 389                  * opcode. In both cases, we do not execute the rest of the
 390                  * package;  We simply close out the parent (finishing the walk of
 391                  * this branch of the tree) and continue execution at the parent
 392                  * level.
 393                  */
 394                 parser_state->aml = parser_state->scope->parse_scope.pkg_end;
 395
 396                 /* In the case of a BREAK, just force a predicate (if any) to FALSE */
 397
 398                 walk_state->control_state->common.value = FALSE;
 399                 status = AE_CTRL_END;
 400                 break;
 401
 402         case AE_CTRL_TRANSFER:
 403
 404                 /* A method call (invocation) -- transfer control */
 405
 406                 status = AE_CTRL_TRANSFER;
 407                 walk_state->prev_op = op;
 408                 walk_state->method_call_op = op;
 409                 walk_state->method_call_node =
 410                     (op->common.value.arg)->common.node;
 411
 412                 /* Will return value (if any) be used by the caller? */
 413
 414                 walk_state->return_used =
 415                     acpi_ds_is_result_used(op, walk_state);
 416                 break;
 417
 418         default:
 419
 420                 status = callback_status;
 421                 if ((callback_status & AE_CODE_MASK) == AE_CODE_CONTROL) {
 422                         status = AE_OK;
 423                 }
 424                 break;
 425         }
 426
 427         return_ACPI_STATUS(status);
 428 }
 429
 430 /*******************************************************************************
 431  *
 432  * FUNCTION:    acpi_ps_parse_aml
 433  *
 434  * PARAMETERS:  walk_state      - Current state
 435  *
 436  *
 437  * RETURN:      Status
 438  *
 439  * DESCRIPTION: Parse raw AML and return a tree of ops
 440  *
 441  ******************************************************************************/
 442
 443 acpi_status acpi_ps_parse_aml(struct acpi_walk_state *walk_state)
 444 {
 445         acpi_status status;
 446         struct acpi_thread_state *thread;
 447         struct acpi_thread_state *prev_walk_list = acpi_gbl_current_walk_list;
 448         struct acpi_walk_state *previous_walk_state;
 449
 450         ACPI_FUNCTION_TRACE(ps_parse_aml);
 451
 452         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 453                           "Entered with WalkState=%p Aml=%p size=%X\n",
 454                           walk_state, walk_state->parser_state.aml,
 455                           walk_state->parser_state.aml_size));
 456
 457         if (!walk_state->parser_state.aml) {
 458                 return_ACPI_STATUS(AE_NULL_OBJECT);
 459         }
 460
 461         /* Create and initialize a new thread state */
 462
 463         thread = acpi_ut_create_thread_state();
 464         if (!thread) {
 465                 if (walk_state->method_desc) {
 466
 467                         /* Executing a control method - additional cleanup */
 468
 469                         acpi_ds_terminate_control_method(walk_state->
 470                                                          method_desc,
 471                                                          walk_state);
 472                 }
 473
 474                 acpi_ds_delete_walk_state(walk_state);
 475                 return_ACPI_STATUS(AE_NO_MEMORY);
 476         }
 477
 478         walk_state->thread = thread;
 479
 480         /*
 481          * If executing a method, the starting sync_level is this method's
 482          * sync_level
 483          */
 484         if (walk_state->method_desc) {
 485                 walk_state->thread->current_sync_level =
 486                     walk_state->method_desc->method.sync_level;
 487         }
 488
 489         acpi_ds_push_walk_state(walk_state, thread);
 490
 491         /*
 492          * This global allows the AML debugger to get a handle to the currently
 493          * executing control method.
 494          */
 495         acpi_gbl_current_walk_list = thread;
 496
 497         /*
 498          * Execute the walk loop as long as there is a valid Walk State. This
 499          * handles nested control method invocations without recursion.
 500          */
 501         ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "State=%p\n", walk_state));
 502
 503         status = AE_OK;
 504         while (walk_state) {
 505                 if (ACPI_SUCCESS(status)) {
 506                         /*
 507                          * The parse_loop executes AML until the method terminates
 508                          * or calls another method.
 509                          */
 510                         status = acpi_ps_parse_loop(walk_state);
 511                 }
 512
 513                 ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 514                                   "Completed one call to walk loop, %s State=%p\n",
 515                                   acpi_format_exception(status), walk_state));
 516
 517                 if (status == AE_CTRL_TRANSFER) {
 518                         /*
 519                          * A method call was detected.
 520                          * Transfer control to the called control method
 521                          */
 522                         status =
 523                             acpi_ds_call_control_method(thread, walk_state,
 524                                                         NULL);
 525                         if (ACPI_FAILURE(status)) {
 526                                 status =
 527                                     acpi_ds_method_error(status, walk_state);
 528                         }
 529
 530                         /*
 531                          * If the transfer to the new method method call worked, a new walk
 532                          * state was created -- get it
 533                          */
 534                         walk_state = acpi_ds_get_current_walk_state(thread);
 535                         continue;
 536                 } else if (status == AE_CTRL_TERMINATE) {
 537                         status = AE_OK;
 538                 } else if ((status != AE_OK) && (walk_state->method_desc)) {
 539
 540                         /* Either the method parse or actual execution failed */
 541
 542                         ACPI_ERROR_METHOD("Method parse/execution failed",
 543                                           walk_state->method_node, NULL,
 544                                           status);
 545
 546                         /* Check for possible multi-thread reentrancy problem */
 547
 548                         if ((status == AE_ALREADY_EXISTS) &&
 549                             (!(walk_state->method_desc->method.
 550                                info_flags & ACPI_METHOD_SERIALIZED))) {
 551                                 /*
 552                                  * Method is not serialized and tried to create an object
 553                                  * twice. The probable cause is that the method cannot
 554                                  * handle reentrancy. Mark as "pending serialized" now, and
 555                                  * then mark "serialized" when the last thread exits.
 556                                  */
 557                                 walk_state->method_desc->method.info_flags |=
 558                                     ACPI_METHOD_SERIALIZED_PENDING;
 559                         }
 560                 }
 561
 562                 /* We are done with this walk, move on to the parent if any */
 563
 564                 walk_state = acpi_ds_pop_walk_state(thread);
 565
 566                 /* Reset the current scope to the beginning of scope stack */
 567
 568                 acpi_ds_scope_stack_clear(walk_state);
 569
 570                 /*
 571                  * If we just returned from the execution of a control method or if we
 572                  * encountered an error during the method parse phase, there's lots of
 573                  * cleanup to do
 574                  */
 575                 if (((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) ==
 576                      ACPI_PARSE_EXECUTE) || (ACPI_FAILURE(status))) {
 577                         acpi_ds_terminate_control_method(walk_state->
 578                                                          method_desc,
 579                                                          walk_state);
 580                 }
 581
 582                 /* Delete this walk state and all linked control states */
 583
 584                 acpi_ps_cleanup_scope(&walk_state->parser_state);
 585                 previous_walk_state = walk_state;
 586
 587                 ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 588                                   "ReturnValue=%p, ImplicitValue=%p State=%p\n",
 589                                   walk_state->return_desc,
 590                                   walk_state->implicit_return_obj, walk_state));
 591
 592                 /* Check if we have restarted a preempted walk */
 593
 594                 walk_state = acpi_ds_get_current_walk_state(thread);
 595                 if (walk_state) {
 596                         if (ACPI_SUCCESS(status)) {
 597                                 /*
 598                                  * There is another walk state, restart it.
 599                                  * If the method return value is not used by the parent,
 600                                  * The object is deleted
 601                                  */
 602                                 if (!previous_walk_state->return_desc) {
 603                                         /*
 604                                          * In slack mode execution, if there is no return value
 605                                          * we should implicitly return zero (0) as a default value.
 606                                          */
 607                                         if (acpi_gbl_enable_interpreter_slack &&
 608                                             !previous_walk_state->
 609                                             implicit_return_obj) {
 610                                                 previous_walk_state->
 611                                                     implicit_return_obj =
 612                                                     acpi_ut_create_integer_object
 613                                                     ((u64) 0);
 614                                                 if (!previous_walk_state->
 615                                                     implicit_return_obj) {
 616                                                         return_ACPI_STATUS
 617                                                             (AE_NO_MEMORY);
 618                                                 }
 619                                         }
 620
 621                                         /* Restart the calling control method */
 622
 623                                         status =
 624                                             acpi_ds_restart_control_method
 625                                             (walk_state,
 626                                              previous_walk_state->
 627                                              implicit_return_obj);
 628                                 } else {
 629                                         /*
 630                                          * We have a valid return value, delete any implicit
 631                                          * return value.
 632                                          */
 633                                         acpi_ds_clear_implicit_return
 634                                             (previous_walk_state);
 635
 636                                         status =
 637                                             acpi_ds_restart_control_method
 638                                             (walk_state,
 639                                              previous_walk_state->return_desc);
 640                                 }
 641                                 if (ACPI_SUCCESS(status)) {
 642                                         walk_state->walk_type |=
 643                                             ACPI_WALK_METHOD_RESTART;
 644                                 }
 645                         } else {
 646                                 /* On error, delete any return object or implicit return */
 647
 648                                 acpi_ut_remove_reference(previous_walk_state->
 649                                                          return_desc);
 650                                 acpi_ds_clear_implicit_return
 651                                     (previous_walk_state);
 652                         }
 653                 }
 654
 655                 /*
 656                  * Just completed a 1st-level method, save the final internal return
 657                  * value (if any)
 658                  */
 659                 else if (previous_walk_state->caller_return_desc) {
 660                         if (previous_walk_state->implicit_return_obj) {
 661                                 *(previous_walk_state->caller_return_desc) =
 662                                     previous_walk_state->implicit_return_obj;
 663                         } else {
 664                                 /* NULL if no return value */
 665
 666                                 *(previous_walk_state->caller_return_desc) =
 667                                     previous_walk_state->return_desc;
 668                         }
 669                 } else {
 670                         if (previous_walk_state->return_desc) {
 671
 672                                 /* Caller doesn't want it, must delete it */
 673
 674                                 acpi_ut_remove_reference(previous_walk_state->
 675                                                          return_desc);
 676                         }
 677                         if (previous_walk_state->implicit_return_obj) {
 678
 679                                 /* Caller doesn't want it, must delete it */
 680
 681                                 acpi_ut_remove_reference(previous_walk_state->
 682                                                          implicit_return_obj);
 683                         }
 684                 }
 685
 686                 acpi_ds_delete_walk_state(previous_walk_state);
 687         }
 688
 689         /* Normal exit */
 690
 691         acpi_ex_release_all_mutexes(thread);
 692         acpi_ut_delete_generic_state(ACPI_CAST_PTR
 693                                      (union acpi_generic_state, thread));
 694         acpi_gbl_current_walk_list = prev_walk_list;
 695         return_ACPI_STATUS(status);
 696 }