LXR linux/drivers/acpi/acpica/dswstate.c

   1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2/******************************************************************************
   3 *
   4 * Module Name: dswstate - Dispatcher parse tree walk management routines
   5 *
   6 * Copyright (C) 2000 - 2018, Intel Corp.
   7 *
   8 *****************************************************************************/
   9
  10#include <acpi/acpi.h>
  11#include "accommon.h"
  12#include "acparser.h"
  13#include "acdispat.h"
  14#include "acnamesp.h"
  15
  16#define _COMPONENT          ACPI_DISPATCHER
  17ACPI_MODULE_NAME("dswstate")
  18
  19  /* Local prototypes */
  20static acpi_status
  21acpi_ds_result_stack_push(struct acpi_walk_state *walk_state);
  22static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state);
  23
  24/*******************************************************************************
  25 *
  26 * FUNCTION:    acpi_ds_result_pop
  27 *
  28 * PARAMETERS:  object              - Where to return the popped object
  29 *              walk_state          - Current Walk state
  30 *
  31 * RETURN:      Status
  32 *
  33 * DESCRIPTION: Pop an object off the top of this walk's result stack
  34 *
  35 ******************************************************************************/
  36
  37acpi_status
  38acpi_ds_result_pop(union acpi_operand_object **object,
  39                   struct acpi_walk_state *walk_state)
  40{
  41        u32 index;
  42        union acpi_generic_state *state;
  43        acpi_status status;
  44
  45        ACPI_FUNCTION_NAME(ds_result_pop);
  46
  47        state = walk_state->results;
  48
  49        /* Incorrect state of result stack */
  50
  51        if (state && !walk_state->result_count) {
  52                ACPI_ERROR((AE_INFO, "No results on result stack"));
  53                return (AE_AML_INTERNAL);
  54        }
  55
  56        if (!state && walk_state->result_count) {
  57                ACPI_ERROR((AE_INFO, "No result state for result stack"));
  58                return (AE_AML_INTERNAL);
  59        }
  60
  61        /* Empty result stack */
  62
  63        if (!state) {
  64                ACPI_ERROR((AE_INFO, "Result stack is empty! State=%p",
  65                            walk_state));
  66                return (AE_AML_NO_RETURN_VALUE);
  67        }
  68
  69        /* Return object of the top element and clean that top element result stack */
  70
  71        walk_state->result_count--;
  72        index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
  73
  74        *object = state->results.obj_desc[index];
  75        if (!*object) {
  76                ACPI_ERROR((AE_INFO,
  77                            "No result objects on result stack, State=%p",
  78                            walk_state));
  79                return (AE_AML_NO_RETURN_VALUE);
  80        }
  81
  82        state->results.obj_desc[index] = NULL;
  83        if (index == 0) {
  84                status = acpi_ds_result_stack_pop(walk_state);
  85                if (ACPI_FAILURE(status)) {
  86                        return (status);
  87                }
  88        }
  89
  90        ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
  91                          "Obj=%p [%s] Index=%X State=%p Num=%X\n", *object,
  92                          acpi_ut_get_object_type_name(*object),
  93                          index, walk_state, walk_state->result_count));
  94
  95        return (AE_OK);
  96}
  97
  98/*******************************************************************************
  99 *
 100 * FUNCTION:    acpi_ds_result_push
 101 *
 102 * PARAMETERS:  object              - Where to return the popped object
 103 *              walk_state          - Current Walk state
 104 *
 105 * RETURN:      Status
 106 *
 107 * DESCRIPTION: Push an object onto the current result stack
 108 *
 109 ******************************************************************************/
 110
 111acpi_status
 112acpi_ds_result_push(union acpi_operand_object *object,
 113                    struct acpi_walk_state *walk_state)
 114{
 115        union acpi_generic_state *state;
 116        acpi_status status;
 117        u32 index;
 118
 119        ACPI_FUNCTION_NAME(ds_result_push);
 120
 121        if (walk_state->result_count > walk_state->result_size) {
 122                ACPI_ERROR((AE_INFO, "Result stack is full"));
 123                return (AE_AML_INTERNAL);
 124        } else if (walk_state->result_count == walk_state->result_size) {
 125
 126                /* Extend the result stack */
 127
 128                status = acpi_ds_result_stack_push(walk_state);
 129                if (ACPI_FAILURE(status)) {
 130                        ACPI_ERROR((AE_INFO,
 131                                    "Failed to extend the result stack"));
 132                        return (status);
 133                }
 134        }
 135
 136        if (!(walk_state->result_count < walk_state->result_size)) {
 137                ACPI_ERROR((AE_INFO, "No free elements in result stack"));
 138                return (AE_AML_INTERNAL);
 139        }
 140
 141        state = walk_state->results;
 142        if (!state) {
 143                ACPI_ERROR((AE_INFO, "No result stack frame during push"));
 144                return (AE_AML_INTERNAL);
 145        }
 146
 147        if (!object) {
 148                ACPI_ERROR((AE_INFO,
 149                            "Null Object! Obj=%p State=%p Num=%u",
 150                            object, walk_state, walk_state->result_count));
 151                return (AE_BAD_PARAMETER);
 152        }
 153
 154        /* Assign the address of object to the top free element of result stack */
 155
 156        index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
 157        state->results.obj_desc[index] = object;
 158        walk_state->result_count++;
 159
 160        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p Num=%X Cur=%X\n",
 161                          object,
 162                          acpi_ut_get_object_type_name((union
 163                                                        acpi_operand_object *)
 164                                                       object), walk_state,
 165                          walk_state->result_count,
 166                          walk_state->current_result));
 167
 168        return (AE_OK);
 169}
 170
 171/*******************************************************************************
 172 *
 173 * FUNCTION:    acpi_ds_result_stack_push
 174 *
 175 * PARAMETERS:  walk_state          - Current Walk state
 176 *
 177 * RETURN:      Status
 178 *
 179 * DESCRIPTION: Push an object onto the walk_state result stack
 180 *
 181 ******************************************************************************/
 182
 183static acpi_status acpi_ds_result_stack_push(struct acpi_walk_state *walk_state)
 184{
 185        union acpi_generic_state *state;
 186
 187        ACPI_FUNCTION_NAME(ds_result_stack_push);
 188
 189        /* Check for stack overflow */
 190
 191        if (((u32) walk_state->result_size + ACPI_RESULTS_FRAME_OBJ_NUM) >
 192            ACPI_RESULTS_OBJ_NUM_MAX) {
 193                ACPI_ERROR((AE_INFO, "Result stack overflow: State=%p Num=%u",
 194                            walk_state, walk_state->result_size));
 195                return (AE_STACK_OVERFLOW);
 196        }
 197
 198        state = acpi_ut_create_generic_state();
 199        if (!state) {
 200                return (AE_NO_MEMORY);
 201        }
 202
 203        state->common.descriptor_type = ACPI_DESC_TYPE_STATE_RESULT;
 204        acpi_ut_push_generic_state(&walk_state->results, state);
 205
 206        /* Increase the length of the result stack by the length of frame */
 207
 208        walk_state->result_size += ACPI_RESULTS_FRAME_OBJ_NUM;
 209
 210        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Results=%p State=%p\n",
 211                          state, walk_state));
 212
 213        return (AE_OK);
 214}
 215
 216/*******************************************************************************
 217 *
 218 * FUNCTION:    acpi_ds_result_stack_pop
 219 *
 220 * PARAMETERS:  walk_state          - Current Walk state
 221 *
 222 * RETURN:      Status
 223 *
 224 * DESCRIPTION: Pop an object off of the walk_state result stack
 225 *
 226 ******************************************************************************/
 227
 228static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state)
 229{
 230        union acpi_generic_state *state;
 231
 232        ACPI_FUNCTION_NAME(ds_result_stack_pop);
 233
 234        /* Check for stack underflow */
 235
 236        if (walk_state->results == NULL) {
 237                ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 238                                  "Result stack underflow - State=%p\n",
 239                                  walk_state));
 240                return (AE_AML_NO_OPERAND);
 241        }
 242
 243        if (walk_state->result_size < ACPI_RESULTS_FRAME_OBJ_NUM) {
 244                ACPI_ERROR((AE_INFO, "Insufficient result stack size"));
 245                return (AE_AML_INTERNAL);
 246        }
 247
 248        state = acpi_ut_pop_generic_state(&walk_state->results);
 249        acpi_ut_delete_generic_state(state);
 250
 251        /* Decrease the length of result stack by the length of frame */
 252
 253        walk_state->result_size -= ACPI_RESULTS_FRAME_OBJ_NUM;
 254
 255        ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 256                          "Result=%p RemainingResults=%X State=%p\n",
 257                          state, walk_state->result_count, walk_state));
 258
 259        return (AE_OK);
 260}
 261
 262/*******************************************************************************
 263 *
 264 * FUNCTION:    acpi_ds_obj_stack_push
 265 *
 266 * PARAMETERS:  object              - Object to push
 267 *              walk_state          - Current Walk state
 268 *
 269 * RETURN:      Status
 270 *
 271 * DESCRIPTION: Push an object onto this walk's object/operand stack
 272 *
 273 ******************************************************************************/
 274
 275acpi_status
 276acpi_ds_obj_stack_push(void *object, struct acpi_walk_state *walk_state)
 277{
 278        ACPI_FUNCTION_NAME(ds_obj_stack_push);
 279
 280        /* Check for stack overflow */
 281
 282        if (walk_state->num_operands >= ACPI_OBJ_NUM_OPERANDS) {
 283                ACPI_ERROR((AE_INFO,
 284                            "Object stack overflow! Obj=%p State=%p #Ops=%u",
 285                            object, walk_state, walk_state->num_operands));
 286                return (AE_STACK_OVERFLOW);
 287        }
 288
 289        /* Put the object onto the stack */
 290
 291        walk_state->operands[walk_state->operand_index] = object;
 292        walk_state->num_operands++;
 293
 294        /* For the usual order of filling the operand stack */
 295
 296        walk_state->operand_index++;
 297
 298        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p #Ops=%X\n",
 299                          object,
 300                          acpi_ut_get_object_type_name((union
 301                                                        acpi_operand_object *)
 302                                                       object), walk_state,
 303                          walk_state->num_operands));
 304
 305        return (AE_OK);
 306}
 307
 308/*******************************************************************************
 309 *
 310 * FUNCTION:    acpi_ds_obj_stack_pop
 311 *
 312 * PARAMETERS:  pop_count           - Number of objects/entries to pop
 313 *              walk_state          - Current Walk state
 314 *
 315 * RETURN:      Status
 316 *
 317 * DESCRIPTION: Pop this walk's object stack. Objects on the stack are NOT
 318 *              deleted by this routine.
 319 *
 320 ******************************************************************************/
 321
 322acpi_status
 323acpi_ds_obj_stack_pop(u32 pop_count, struct acpi_walk_state *walk_state)
 324{
 325        u32 i;
 326
 327        ACPI_FUNCTION_NAME(ds_obj_stack_pop);
 328
 329        for (i = 0; i < pop_count; i++) {
 330
 331                /* Check for stack underflow */
 332
 333                if (walk_state->num_operands == 0) {
 334                        ACPI_ERROR((AE_INFO,
 335                                    "Object stack underflow! Count=%X State=%p #Ops=%u",
 336                                    pop_count, walk_state,
 337                                    walk_state->num_operands));
 338                        return (AE_STACK_UNDERFLOW);
 339                }
 340
 341                /* Just set the stack entry to null */
 342
 343                walk_state->num_operands--;
 344                walk_state->operands[walk_state->num_operands] = NULL;
 345        }
 346
 347        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%u\n",
 348                          pop_count, walk_state, walk_state->num_operands));
 349
 350        return (AE_OK);
 351}
 352
 353/*******************************************************************************
 354 *
 355 * FUNCTION:    acpi_ds_obj_stack_pop_and_delete
 356 *
 357 * PARAMETERS:  pop_count           - Number of objects/entries to pop
 358 *              walk_state          - Current Walk state
 359 *
 360 * RETURN:      Status
 361 *
 362 * DESCRIPTION: Pop this walk's object stack and delete each object that is
 363 *              popped off.
 364 *
 365 ******************************************************************************/
 366
 367void
 368acpi_ds_obj_stack_pop_and_delete(u32 pop_count,
 369                                 struct acpi_walk_state *walk_state)
 370{
 371        s32 i;
 372        union acpi_operand_object *obj_desc;
 373
 374        ACPI_FUNCTION_NAME(ds_obj_stack_pop_and_delete);
 375
 376        if (pop_count == 0) {
 377                return;
 378        }
 379
 380        for (i = (s32)pop_count - 1; i >= 0; i--) {
 381                if (walk_state->num_operands == 0) {
 382                        return;
 383                }
 384
 385                /* Pop the stack and delete an object if present in this stack entry */
 386
 387                walk_state->num_operands--;
 388                obj_desc = walk_state->operands[i];
 389                if (obj_desc) {
 390                        acpi_ut_remove_reference(walk_state->operands[i]);
 391                        walk_state->operands[i] = NULL;
 392                }
 393        }
 394
 395        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%X\n",
 396                          pop_count, walk_state, walk_state->num_operands));
 397}
 398
 399/*******************************************************************************
 400 *
 401 * FUNCTION:    acpi_ds_get_current_walk_state
 402 *
 403 * PARAMETERS:  thread          - Get current active state for this Thread
 404 *
 405 * RETURN:      Pointer to the current walk state
 406 *
 407 * DESCRIPTION: Get the walk state that is at the head of the list (the "current"
 408 *              walk state.)
 409 *
 410 ******************************************************************************/
 411
 412struct acpi_walk_state *acpi_ds_get_current_walk_state(struct acpi_thread_state
 413                                                       *thread)
 414{
 415        ACPI_FUNCTION_NAME(ds_get_current_walk_state);
 416
 417        if (!thread) {
 418                return (NULL);
 419        }
 420
 421        ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "Current WalkState %p\n",
 422                          thread->walk_state_list));
 423
 424        return (thread->walk_state_list);
 425}
 426
 427/*******************************************************************************
 428 *
 429 * FUNCTION:    acpi_ds_push_walk_state
 430 *
 431 * PARAMETERS:  walk_state      - State to push
 432 *              thread          - Thread state object
 433 *
 434 * RETURN:      None
 435 *
 436 * DESCRIPTION: Place the Thread state at the head of the state list
 437 *
 438 ******************************************************************************/
 439
 440void
 441acpi_ds_push_walk_state(struct acpi_walk_state *walk_state,
 442                        struct acpi_thread_state *thread)
 443{
 444        ACPI_FUNCTION_TRACE(ds_push_walk_state);
 445
 446        walk_state->next = thread->walk_state_list;
 447        thread->walk_state_list = walk_state;
 448
 449        return_VOID;
 450}
 451
 452/*******************************************************************************
 453 *
 454 * FUNCTION:    acpi_ds_pop_walk_state
 455 *
 456 * PARAMETERS:  thread      - Current thread state
 457 *
 458 * RETURN:      A walk_state object popped from the thread's stack
 459 *
 460 * DESCRIPTION: Remove and return the walkstate object that is at the head of
 461 *              the walk stack for the given walk list. NULL indicates that
 462 *              the list is empty.
 463 *
 464 ******************************************************************************/
 465
 466struct acpi_walk_state *acpi_ds_pop_walk_state(struct acpi_thread_state *thread)
 467{
 468        struct acpi_walk_state *walk_state;
 469
 470        ACPI_FUNCTION_TRACE(ds_pop_walk_state);
 471
 472        walk_state = thread->walk_state_list;
 473
 474        if (walk_state) {
 475
 476                /* Next walk state becomes the current walk state */
 477
 478                thread->walk_state_list = walk_state->next;
 479
 480                /*
 481                 * Don't clear the NEXT field, this serves as an indicator
 482                 * that there is a parent WALK STATE
 483                 * Do Not: walk_state->Next = NULL;
 484                 */
 485        }
 486
 487        return_PTR(walk_state);
 488}
 489
 490/*******************************************************************************
 491 *
 492 * FUNCTION:    acpi_ds_create_walk_state
 493 *
 494 * PARAMETERS:  owner_id        - ID for object creation
 495 *              origin          - Starting point for this walk
 496 *              method_desc     - Method object
 497 *              thread          - Current thread state
 498 *
 499 * RETURN:      Pointer to the new walk state.
 500 *
 501 * DESCRIPTION: Allocate and initialize a new walk state. The current walk
 502 *              state is set to this new state.
 503 *
 504 ******************************************************************************/
 505
 506struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id,
 507                                                  union acpi_parse_object
 508                                                  *origin,
 509                                                  union acpi_operand_object
 510                                                  *method_desc,
 511                                                  struct acpi_thread_state
 512                                                  *thread)
 513{
 514        struct acpi_walk_state *walk_state;
 515
 516        ACPI_FUNCTION_TRACE(ds_create_walk_state);
 517
 518        walk_state = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_walk_state));
 519        if (!walk_state) {
 520                return_PTR(NULL);
 521        }
 522
 523        walk_state->descriptor_type = ACPI_DESC_TYPE_WALK;
 524        walk_state->method_desc = method_desc;
 525        walk_state->owner_id = owner_id;
 526        walk_state->origin = origin;
 527        walk_state->thread = thread;
 528
 529        walk_state->parser_state.start_op = origin;
 530
 531        /* Init the method args/local */
 532
 533#if (!defined (ACPI_NO_METHOD_EXECUTION) && !defined (ACPI_CONSTANT_EVAL_ONLY))
 534        acpi_ds_method_data_init(walk_state);
 535#endif
 536
 537        /* Put the new state at the head of the walk list */
 538
 539        if (thread) {
 540                acpi_ds_push_walk_state(walk_state, thread);
 541        }
 542
 543        return_PTR(walk_state);
 544}
 545
 546/*******************************************************************************
 547 *
 548 * FUNCTION:    acpi_ds_init_aml_walk
 549 *
 550 * PARAMETERS:  walk_state      - New state to be initialized
 551 *              op              - Current parse op
 552 *              method_node     - Control method NS node, if any
 553 *              aml_start       - Start of AML
 554 *              aml_length      - Length of AML
 555 *              info            - Method info block (params, etc.)
 556 *              pass_number     - 1, 2, or 3
 557 *
 558 * RETURN:      Status
 559 *
 560 * DESCRIPTION: Initialize a walk state for a pass 1 or 2 parse tree walk
 561 *
 562 ******************************************************************************/
 563
 564acpi_status
 565acpi_ds_init_aml_walk(struct acpi_walk_state *walk_state,
 566                      union acpi_parse_object *op,
 567                      struct acpi_namespace_node *method_node,
 568                      u8 * aml_start,
 569                      u32 aml_length,
 570                      struct acpi_evaluate_info *info, u8 pass_number)
 571{
 572        acpi_status status;
 573        struct acpi_parse_state *parser_state = &walk_state->parser_state;
 574        union acpi_parse_object *extra_op;
 575
 576        ACPI_FUNCTION_TRACE(ds_init_aml_walk);
 577
 578        walk_state->parser_state.aml =
 579            walk_state->parser_state.aml_start = aml_start;
 580        walk_state->parser_state.aml_end =
 581            walk_state->parser_state.pkg_end = aml_start + aml_length;
 582
 583        /* The next_op of the next_walk will be the beginning of the method */
 584
 585        walk_state->next_op = NULL;
 586        walk_state->pass_number = pass_number;
 587
 588        if (info) {
 589                walk_state->params = info->parameters;
 590                walk_state->caller_return_desc = &info->return_object;
 591        }
 592
 593        status = acpi_ps_init_scope(&walk_state->parser_state, op);
 594        if (ACPI_FAILURE(status)) {
 595                return_ACPI_STATUS(status);
 596        }
 597
 598        if (method_node) {
 599                walk_state->parser_state.start_node = method_node;
 600                walk_state->walk_type = ACPI_WALK_METHOD;
 601                walk_state->method_node = method_node;
 602                walk_state->method_desc =
 603                    acpi_ns_get_attached_object(method_node);
 604
 605                /* Push start scope on scope stack and make it current  */
 606
 607                status =
 608                    acpi_ds_scope_stack_push(method_node, ACPI_TYPE_METHOD,
 609                                             walk_state);
 610                if (ACPI_FAILURE(status)) {
 611                        return_ACPI_STATUS(status);
 612                }
 613
 614                /* Init the method arguments */
 615
 616                status = acpi_ds_method_data_init_args(walk_state->params,
 617                                                       ACPI_METHOD_NUM_ARGS,
 618                                                       walk_state);
 619                if (ACPI_FAILURE(status)) {
 620                        return_ACPI_STATUS(status);
 621                }
 622        } else {
 623                /*
 624                 * Setup the current scope.
 625                 * Find a Named Op that has a namespace node associated with it.
 626                 * search upwards from this Op. Current scope is the first
 627                 * Op with a namespace node.
 628                 */
 629                extra_op = parser_state->start_op;
 630                while (extra_op && !extra_op->common.node) {
 631                        extra_op = extra_op->common.parent;
 632                }
 633
 634                if (!extra_op) {
 635                        parser_state->start_node = NULL;
 636                } else {
 637                        parser_state->start_node = extra_op->common.node;
 638                }
 639
 640                if (parser_state->start_node) {
 641
 642                        /* Push start scope on scope stack and make it current  */
 643
 644                        status =
 645                            acpi_ds_scope_stack_push(parser_state->start_node,
 646                                                     parser_state->start_node->
 647                                                     type, walk_state);
 648                        if (ACPI_FAILURE(status)) {
 649                                return_ACPI_STATUS(status);
 650                        }
 651                }
 652        }
 653
 654        status = acpi_ds_init_callbacks(walk_state, pass_number);
 655        return_ACPI_STATUS(status);
 656}
 657
 658/*******************************************************************************
 659 *
 660 * FUNCTION:    acpi_ds_delete_walk_state
 661 *
 662 * PARAMETERS:  walk_state      - State to delete
 663 *
 664 * RETURN:      Status
 665 *
 666 * DESCRIPTION: Delete a walk state including all internal data structures
 667 *
 668 ******************************************************************************/
 669
 670void acpi_ds_delete_walk_state(struct acpi_walk_state *walk_state)
 671{
 672        union acpi_generic_state *state;
 673
 674        ACPI_FUNCTION_TRACE_PTR(ds_delete_walk_state, walk_state);
 675
 676        if (!walk_state) {
 677                return_VOID;
 678        }
 679
 680        if (walk_state->descriptor_type != ACPI_DESC_TYPE_WALK) {
 681                ACPI_ERROR((AE_INFO, "%p is not a valid walk state",
 682                            walk_state));
 683                return_VOID;
 684        }
 685
 686        /* There should not be any open scopes */
 687
 688        if (walk_state->parser_state.scope) {
 689                ACPI_ERROR((AE_INFO, "%p walk still has a scope list",
 690                            walk_state));
 691                acpi_ps_cleanup_scope(&walk_state->parser_state);
 692        }
 693
 694        /* Always must free any linked control states */
 695
 696        while (walk_state->control_state) {
 697                state = walk_state->control_state;
 698                walk_state->control_state = state->common.next;
 699
 700                acpi_ut_delete_generic_state(state);
 701        }
 702
 703        /* Always must free any linked parse states */
 704
 705        while (walk_state->scope_info) {
 706                state = walk_state->scope_info;
 707                walk_state->scope_info = state->common.next;
 708
 709                acpi_ut_delete_generic_state(state);
 710        }
 711
 712        /* Always must free any stacked result states */
 713
 714        while (walk_state->results) {
 715                state = walk_state->results;
 716                walk_state->results = state->common.next;
 717
 718                acpi_ut_delete_generic_state(state);
 719        }
 720
 721        ACPI_FREE(walk_state);
 722        return_VOID;
 723}
 724