drivers/acpi/dispatcher/dsmethod.c

   1 /******************************************************************************
   2  *
   3  * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2006, R. Byron Moore
   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 <acpi/acparser.h>
  46 #include <acpi/amlcode.h>
  47 #include <acpi/acdispat.h>
  48 #include <acpi/acinterp.h>
  49 #include <acpi/acnamesp.h>
  50 #include <acpi/acdisasm.h>
  51
  52 #define _COMPONENT          ACPI_DISPATCHER
  53 ACPI_MODULE_NAME("dsmethod")
  54
  55 /*******************************************************************************
  56  *
  57  * FUNCTION:    acpi_ds_method_error
  58  *
  59  * PARAMETERS:  Status          - Execution status
  60  *              walk_state      - Current state
  61  *
  62  * RETURN:      Status
  63  *
  64  * DESCRIPTION: Called on method error. Invoke the global exception handler if
  65  *              present, dump the method data if the disassembler is configured
  66  *
  67  *              Note: Allows the exception handler to change the status code
  68  *
  69  ******************************************************************************/
  70 acpi_status
  71 acpi_ds_method_error(acpi_status status, struct acpi_walk_state *walk_state)
  72 {
  73         ACPI_FUNCTION_ENTRY();
  74
  75         /* Ignore AE_OK and control exception codes */
  76
  77         if (ACPI_SUCCESS(status) || (status & AE_CODE_CONTROL)) {
  78                 return (status);
  79         }
  80
  81         /* Invoke the global exception handler */
  82
  83         if (acpi_gbl_exception_handler) {
  84
  85                 /* Exit the interpreter, allow handler to execute methods */
  86
  87                 acpi_ex_exit_interpreter();
  88
  89                 /*
  90                  * Handler can map the exception code to anything it wants, including
  91                  * AE_OK, in which case the executing method will not be aborted.
  92                  */
  93                 status = acpi_gbl_exception_handler(status,
  94                                                     walk_state->method_node ?
  95                                                     walk_state->method_node->
  96                                                     name.integer : 0,
  97                                                     walk_state->opcode,
  98                                                     walk_state->aml_offset,
  99                                                     NULL);
 100                 (void)acpi_ex_enter_interpreter();
 101         }
 102 #ifdef ACPI_DISASSEMBLER
 103         if (ACPI_FAILURE(status)) {
 104
 105                 /* Display method locals/args if disassembler is present */
 106
 107                 acpi_dm_dump_method_info(status, walk_state, walk_state->op);
 108         }
 109 #endif
 110
 111         return (status);
 112 }
 113
 114 /*******************************************************************************
 115  *
 116  * FUNCTION:    acpi_ds_begin_method_execution
 117  *
 118  * PARAMETERS:  method_node         - Node of the method
 119  *              obj_desc            - The method object
 120  *              calling_method_node - Caller of this method (if non-null)
 121  *
 122  * RETURN:      Status
 123  *
 124  * DESCRIPTION: Prepare a method for execution.  Parses the method if necessary,
 125  *              increments the thread count, and waits at the method semaphore
 126  *              for clearance to execute.
 127  *
 128  ******************************************************************************/
 129
 130 acpi_status
 131 acpi_ds_begin_method_execution(struct acpi_namespace_node * method_node,
 132                                union acpi_operand_object * obj_desc,
 133                                struct acpi_namespace_node * calling_method_node)
 134 {
 135         acpi_status status = AE_OK;
 136
 137         ACPI_FUNCTION_TRACE_PTR(ds_begin_method_execution, method_node);
 138
 139         if (!method_node) {
 140                 return_ACPI_STATUS(AE_NULL_ENTRY);
 141         }
 142
 143         /* Prevent wraparound of thread count */
 144
 145         if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {
 146                 ACPI_ERROR((AE_INFO,
 147                             "Method reached maximum reentrancy limit (255)"));
 148                 return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
 149         }
 150
 151         /*
 152          * If there is a concurrency limit on this method, we need to
 153          * obtain a unit from the method semaphore.
 154          */
 155         if (obj_desc->method.semaphore) {
 156                 /*
 157                  * Allow recursive method calls, up to the reentrancy/concurrency
 158                  * limit imposed by the SERIALIZED rule and the sync_level method
 159                  * parameter.
 160                  *
 161                  * The point of this code is to avoid permanently blocking a
 162                  * thread that is making recursive method calls.
 163                  */
 164                 if (method_node == calling_method_node) {
 165                         if (obj_desc->method.thread_count >=
 166                             obj_desc->method.concurrency) {
 167                                 return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
 168                         }
 169                 }
 170
 171                 /*
 172                  * Get a unit from the method semaphore. This releases the
 173                  * interpreter if we block (then reacquires it)
 174                  */
 175                 status =
 176                     acpi_ex_system_wait_semaphore(obj_desc->method.semaphore,
 177                                                   ACPI_WAIT_FOREVER);
 178                 if (ACPI_FAILURE(status)) {
 179                         return_ACPI_STATUS(status);
 180                 }
 181         }
 182
 183         /*
 184          * Allocate an Owner ID for this method, only if this is the first thread
 185          * to begin concurrent execution. We only need one owner_id, even if the
 186          * method is invoked recursively.
 187          */
 188         if (!obj_desc->method.owner_id) {
 189                 status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
 190                 if (ACPI_FAILURE(status)) {
 191                         goto cleanup;
 192                 }
 193         }
 194
 195         /*
 196          * Increment the method parse tree thread count since it has been
 197          * reentered one more time (even if it is the same thread)
 198          */
 199         obj_desc->method.thread_count++;
 200         return_ACPI_STATUS(status);
 201
 202       cleanup:
 203         /* On error, must signal the method semaphore if present */
 204
 205         if (obj_desc->method.semaphore) {
 206                 (void)acpi_os_signal_semaphore(obj_desc->method.semaphore, 1);
 207         }
 208         return_ACPI_STATUS(status);
 209 }
 210
 211 /*******************************************************************************
 212  *
 213  * FUNCTION:    acpi_ds_call_control_method
 214  *
 215  * PARAMETERS:  Thread              - Info for this thread
 216  *              this_walk_state     - Current walk state
 217  *              Op                  - Current Op to be walked
 218  *
 219  * RETURN:      Status
 220  *
 221  * DESCRIPTION: Transfer execution to a called control method
 222  *
 223  ******************************************************************************/
 224
 225 acpi_status
 226 acpi_ds_call_control_method(struct acpi_thread_state *thread,
 227                             struct acpi_walk_state *this_walk_state,
 228                             union acpi_parse_object *op)
 229 {
 230         acpi_status status;
 231         struct acpi_namespace_node *method_node;
 232         struct acpi_walk_state *next_walk_state = NULL;
 233         union acpi_operand_object *obj_desc;
 234         struct acpi_evaluate_info *info;
 235         u32 i;
 236
 237         ACPI_FUNCTION_TRACE_PTR(ds_call_control_method, this_walk_state);
 238
 239         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 240                           "Execute method %p, currentstate=%p\n",
 241                           this_walk_state->prev_op, this_walk_state));
 242
 243         /*
 244          * Get the namespace entry for the control method we are about to call
 245          */
 246         method_node = this_walk_state->method_call_node;
 247         if (!method_node) {
 248                 return_ACPI_STATUS(AE_NULL_ENTRY);
 249         }
 250
 251         obj_desc = acpi_ns_get_attached_object(method_node);
 252         if (!obj_desc) {
 253                 return_ACPI_STATUS(AE_NULL_OBJECT);
 254         }
 255
 256         /* Init for new method, possibly wait on concurrency semaphore */
 257
 258         status = acpi_ds_begin_method_execution(method_node, obj_desc,
 259                                                 this_walk_state->method_node);
 260         if (ACPI_FAILURE(status)) {
 261                 return_ACPI_STATUS(status);
 262         }
 263
 264         /*
 265          * 1) Parse the method. All "normal" methods are parsed for each execution.
 266          * Internal methods (_OSI, etc.) do not require parsing.
 267          */
 268         if (!(obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY)) {
 269
 270                 /* Create a new walk state for the parse */
 271
 272                 next_walk_state =
 273                     acpi_ds_create_walk_state(obj_desc->method.owner_id, op,
 274                                               obj_desc, NULL);
 275                 if (!next_walk_state) {
 276                         status = AE_NO_MEMORY;
 277                         goto cleanup;
 278                 }
 279
 280                 /* Create and init a parse tree root */
 281
 282                 op = acpi_ps_create_scope_op();
 283                 if (!op) {
 284                         status = AE_NO_MEMORY;
 285                         goto cleanup;
 286                 }
 287
 288                 status = acpi_ds_init_aml_walk(next_walk_state, op, method_node,
 289                                                obj_desc->method.aml_start,
 290                                                obj_desc->method.aml_length,
 291                                                NULL, 1);
 292                 if (ACPI_FAILURE(status)) {
 293                         acpi_ps_delete_parse_tree(op);
 294                         goto cleanup;
 295                 }
 296
 297                 /* Begin AML parse (deletes next_walk_state) */
 298
 299                 status = acpi_ps_parse_aml(next_walk_state);
 300                 acpi_ps_delete_parse_tree(op);
 301                 if (ACPI_FAILURE(status)) {
 302                         goto cleanup;
 303                 }
 304         }
 305
 306         /* 2) Begin method execution. Create a new walk state */
 307
 308         next_walk_state = acpi_ds_create_walk_state(obj_desc->method.owner_id,
 309                                                     NULL, obj_desc, thread);
 310         if (!next_walk_state) {
 311                 status = AE_NO_MEMORY;
 312                 goto cleanup;
 313         }
 314
 315         /*
 316          * The resolved arguments were put on the previous walk state's operand
 317          * stack. Operands on the previous walk state stack always
 318          * start at index 0. Also, null terminate the list of arguments
 319          */
 320         this_walk_state->operands[this_walk_state->num_operands] = NULL;
 321
 322         /*
 323          * Allocate and initialize the evaluation information block
 324          * TBD: this is somewhat inefficient, should change interface to
 325          * ds_init_aml_walk. For now, keeps this struct off the CPU stack
 326          */
 327         info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
 328         if (!info) {
 329                 return_ACPI_STATUS(AE_NO_MEMORY);
 330         }
 331
 332         info->parameters = &this_walk_state->operands[0];
 333         info->parameter_type = ACPI_PARAM_ARGS;
 334
 335         status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
 336                                        obj_desc->method.aml_start,
 337                                        obj_desc->method.aml_length, info, 3);
 338
 339         ACPI_FREE(info);
 340         if (ACPI_FAILURE(status)) {
 341                 goto cleanup;
 342         }
 343
 344         /*
 345          * Delete the operands on the previous walkstate operand stack
 346          * (they were copied to new objects)
 347          */
 348         for (i = 0; i < obj_desc->method.param_count; i++) {
 349                 acpi_ut_remove_reference(this_walk_state->operands[i]);
 350                 this_walk_state->operands[i] = NULL;
 351         }
 352
 353         /* Clear the operand stack */
 354
 355         this_walk_state->num_operands = 0;
 356
 357         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 358                           "Starting nested execution, newstate=%p\n",
 359                           next_walk_state));
 360
 361         /* Invoke an internal method if necessary */
 362
 363         if (obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY) {
 364                 status = obj_desc->method.implementation(next_walk_state);
 365         }
 366
 367         return_ACPI_STATUS(status);
 368
 369       cleanup:
 370
 371         /* On error, we must terminate the method properly */
 372
 373         acpi_ds_terminate_control_method(obj_desc, next_walk_state);
 374         if (next_walk_state) {
 375                 acpi_ds_delete_walk_state(next_walk_state);
 376         }
 377
 378         return_ACPI_STATUS(status);
 379 }
 380
 381 /*******************************************************************************
 382  *
 383  * FUNCTION:    acpi_ds_restart_control_method
 384  *
 385  * PARAMETERS:  walk_state          - State for preempted method (caller)
 386  *              return_desc         - Return value from the called method
 387  *
 388  * RETURN:      Status
 389  *
 390  * DESCRIPTION: Restart a method that was preempted by another (nested) method
 391  *              invocation.  Handle the return value (if any) from the callee.
 392  *
 393  ******************************************************************************/
 394
 395 acpi_status
 396 acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
 397                                union acpi_operand_object *return_desc)
 398 {
 399         acpi_status status;
 400         int same_as_implicit_return;
 401
 402         ACPI_FUNCTION_TRACE_PTR(ds_restart_control_method, walk_state);
 403
 404         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 405                           "****Restart [%4.4s] Op %p ReturnValueFromCallee %p\n",
 406                           (char *)&walk_state->method_node->name,
 407                           walk_state->method_call_op, return_desc));
 408
 409         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 410                           "    ReturnFromThisMethodUsed?=%X ResStack %p Walk %p\n",
 411                           walk_state->return_used,
 412                           walk_state->results, walk_state));
 413
 414         /* Did the called method return a value? */
 415
 416         if (return_desc) {
 417
 418                 /* Is the implicit return object the same as the return desc? */
 419
 420                 same_as_implicit_return =
 421                     (walk_state->implicit_return_obj == return_desc);
 422
 423                 /* Are we actually going to use the return value? */
 424
 425                 if (walk_state->return_used) {
 426
 427                         /* Save the return value from the previous method */
 428
 429                         status = acpi_ds_result_push(return_desc, walk_state);
 430                         if (ACPI_FAILURE(status)) {
 431                                 acpi_ut_remove_reference(return_desc);
 432                                 return_ACPI_STATUS(status);
 433                         }
 434
 435                         /*
 436                          * Save as THIS method's return value in case it is returned
 437                          * immediately to yet another method
 438                          */
 439                         walk_state->return_desc = return_desc;
 440                 }
 441
 442                 /*
 443                  * The following code is the optional support for the so-called
 444                  * "implicit return". Some AML code assumes that the last value of the
 445                  * method is "implicitly" returned to the caller, in the absence of an
 446                  * explicit return value.
 447                  *
 448                  * Just save the last result of the method as the return value.
 449                  *
 450                  * NOTE: this is optional because the ASL language does not actually
 451                  * support this behavior.
 452                  */
 453                 else if (!acpi_ds_do_implicit_return
 454                          (return_desc, walk_state, FALSE)
 455                          || same_as_implicit_return) {
 456                         /*
 457                          * Delete the return value if it will not be used by the
 458                          * calling method or remove one reference if the explicit return
 459                          * is the same as the implicit return value.
 460                          */
 461                         acpi_ut_remove_reference(return_desc);
 462                 }
 463         }
 464
 465         return_ACPI_STATUS(AE_OK);
 466 }
 467
 468 /*******************************************************************************
 469  *
 470  * FUNCTION:    acpi_ds_terminate_control_method
 471  *
 472  * PARAMETERS:  method_desc         - Method object
 473  *              walk_state          - State associated with the method
 474  *
 475  * RETURN:      None
 476  *
 477  * DESCRIPTION: Terminate a control method.  Delete everything that the method
 478  *              created, delete all locals and arguments, and delete the parse
 479  *              tree if requested.
 480  *
 481  ******************************************************************************/
 482
 483 void
 484 acpi_ds_terminate_control_method(union acpi_operand_object *method_desc,
 485                                  struct acpi_walk_state *walk_state)
 486 {
 487         struct acpi_namespace_node *method_node;
 488         acpi_status status;
 489
 490         ACPI_FUNCTION_TRACE_PTR(ds_terminate_control_method, walk_state);
 491
 492         /* method_desc is required, walk_state is optional */
 493
 494         if (!method_desc) {
 495                 return_VOID;
 496         }
 497
 498         if (walk_state) {
 499
 500                 /* Delete all arguments and locals */
 501
 502                 acpi_ds_method_data_delete_all(walk_state);
 503         }
 504
 505         /*
 506          * Lock the parser while we terminate this method.
 507          * If this is the last thread executing the method,
 508          * we have additional cleanup to perform
 509          */
 510         status = acpi_ut_acquire_mutex(ACPI_MTX_CONTROL_METHOD);
 511         if (ACPI_FAILURE(status)) {
 512                 return_VOID;
 513         }
 514
 515         /* Signal completion of the execution of this method if necessary */
 516
 517         if (method_desc->method.semaphore) {
 518                 status =
 519                     acpi_os_signal_semaphore(method_desc->method.semaphore, 1);
 520                 if (ACPI_FAILURE(status)) {
 521
 522                         /* Ignore error and continue */
 523
 524                         ACPI_EXCEPTION((AE_INFO, status,
 525                                         "Could not signal method semaphore"));
 526                 }
 527         }
 528
 529         if (walk_state) {
 530                 /*
 531                  * Delete any objects created by this method during execution.
 532                  * The method Node is stored in the walk state
 533                  */
 534                 method_node = walk_state->method_node;
 535
 536                 /* Lock namespace for possible update */
 537
 538                 status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 539                 if (ACPI_FAILURE(status)) {
 540                         goto exit;
 541                 }
 542
 543                 /*
 544                  * Delete any namespace entries created immediately underneath
 545                  * the method
 546                  */
 547                 if (method_node && method_node->child) {
 548                         acpi_ns_delete_namespace_subtree(method_node);
 549                 }
 550
 551                 /*
 552                  * Delete any namespace entries created anywhere else within
 553                  * the namespace by the execution of this method
 554                  */
 555                 acpi_ns_delete_namespace_by_owner(method_desc->method.owner_id);
 556                 status = acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 557         }
 558
 559         /* Decrement the thread count on the method */
 560
 561         if (method_desc->method.thread_count) {
 562                 method_desc->method.thread_count--;
 563         } else {
 564                 ACPI_ERROR((AE_INFO, "Invalid zero thread count in method"));
 565         }
 566
 567         /* Are there any other threads currently executing this method? */
 568
 569         if (method_desc->method.thread_count) {
 570                 /*
 571                  * Additional threads. Do not release the owner_id in this case,
 572                  * we immediately reuse it for the next thread executing this method
 573                  */
 574                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 575                                   "*** Completed execution of one thread, %d threads remaining\n",
 576                                   method_desc->method.thread_count));
 577         } else {
 578                 /* This is the only executing thread for this method */
 579
 580                 /*
 581                  * Support to dynamically change a method from not_serialized to
 582                  * Serialized if it appears that the method is incorrectly written and
 583                  * does not support multiple thread execution.  The best example of this
 584                  * is if such a method creates namespace objects and blocks.  A second
 585                  * thread will fail with an AE_ALREADY_EXISTS exception
 586                  *
 587                  * This code is here because we must wait until the last thread exits
 588                  * before creating the synchronization semaphore.
 589                  */
 590                 if ((method_desc->method.concurrency == 1) &&
 591                     (!method_desc->method.semaphore)) {
 592                         status = acpi_os_create_semaphore(1, 1,
 593                                                           &method_desc->method.
 594                                                           semaphore);
 595                 }
 596
 597                 /* No more threads, we can free the owner_id */
 598
 599                 acpi_ut_release_owner_id(&method_desc->method.owner_id);
 600         }
 601
 602       exit:
 603         (void)acpi_ut_release_mutex(ACPI_MTX_CONTROL_METHOD);
 604         return_VOID;
 605 }
 606
 607 #ifdef ACPI_INIT_PARSE_METHODS
 608         /*
 609          * Note 11/2005: Removed this code to parse all methods during table
 610          * load because it causes problems if there are any errors during the
 611          * parse. Also, it seems like overkill and we probably don't want to
 612          * abort a table load because of an issue with a single method.
 613          */
 614
 615 /*******************************************************************************
 616  *
 617  * FUNCTION:    acpi_ds_parse_method
 618  *
 619  * PARAMETERS:  Node        - Method node
 620  *
 621  * RETURN:      Status
 622  *
 623  * DESCRIPTION: Parse the AML that is associated with the method.
 624  *
 625  * MUTEX:       Assumes parser is locked
 626  *
 627  ******************************************************************************/
 628
 629 acpi_status acpi_ds_parse_method(struct acpi_namespace_node *node)
 630 {
 631         acpi_status status;
 632         union acpi_operand_object *obj_desc;
 633         union acpi_parse_object *op;
 634         struct acpi_walk_state *walk_state;
 635
 636         ACPI_FUNCTION_TRACE_PTR(ds_parse_method, node);
 637
 638         /* Parameter Validation */
 639
 640         if (!node) {
 641                 return_ACPI_STATUS(AE_NULL_ENTRY);
 642         }
 643
 644         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 645                           "**** Parsing [%4.4s] **** NamedObj=%p\n",
 646                           acpi_ut_get_node_name(node), node));
 647
 648         /* Extract the method object from the method Node */
 649
 650         obj_desc = acpi_ns_get_attached_object(node);
 651         if (!obj_desc) {
 652                 return_ACPI_STATUS(AE_NULL_OBJECT);
 653         }
 654
 655         /* Create a mutex for the method if there is a concurrency limit */
 656
 657         if ((obj_desc->method.concurrency != ACPI_INFINITE_CONCURRENCY) &&
 658             (!obj_desc->method.semaphore)) {
 659                 status = acpi_os_create_semaphore(obj_desc->method.concurrency,
 660                                                   obj_desc->method.concurrency,
 661                                                   &obj_desc->method.semaphore);
 662                 if (ACPI_FAILURE(status)) {
 663                         return_ACPI_STATUS(status);
 664                 }
 665         }
 666
 667         /*
 668          * Allocate a new parser op to be the root of the parsed
 669          * method tree
 670          */
 671         op = acpi_ps_alloc_op(AML_METHOD_OP);
 672         if (!op) {
 673                 return_ACPI_STATUS(AE_NO_MEMORY);
 674         }
 675
 676         /* Init new op with the method name and pointer back to the Node */
 677
 678         acpi_ps_set_name(op, node->name.integer);
 679         op->common.node = node;
 680
 681         /*
 682          * Get a new owner_id for objects created by this method. Namespace
 683          * objects (such as Operation Regions) can be created during the
 684          * first pass parse.
 685          */
 686         status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
 687         if (ACPI_FAILURE(status)) {
 688                 goto cleanup;
 689         }
 690
 691         /* Create and initialize a new walk state */
 692
 693         walk_state =
 694             acpi_ds_create_walk_state(obj_desc->method.owner_id, NULL, NULL,
 695                                       NULL);
 696         if (!walk_state) {
 697                 status = AE_NO_MEMORY;
 698                 goto cleanup2;
 699         }
 700
 701         status = acpi_ds_init_aml_walk(walk_state, op, node,
 702                                        obj_desc->method.aml_start,
 703                                        obj_desc->method.aml_length, NULL, 1);
 704         if (ACPI_FAILURE(status)) {
 705                 acpi_ds_delete_walk_state(walk_state);
 706                 goto cleanup2;
 707         }
 708
 709         /*
 710          * Parse the method, first pass
 711          *
 712          * The first pass load is where newly declared named objects are added into
 713          * the namespace.  Actual evaluation of the named objects (what would be
 714          * called a "second pass") happens during the actual execution of the
 715          * method so that operands to the named objects can take on dynamic
 716          * run-time values.
 717          */
 718         status = acpi_ps_parse_aml(walk_state);
 719         if (ACPI_FAILURE(status)) {
 720                 goto cleanup2;
 721         }
 722
 723         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 724                           "**** [%4.4s] Parsed **** NamedObj=%p Op=%p\n",
 725                           acpi_ut_get_node_name(node), node, op));
 726
 727         /*
 728          * Delete the parse tree. We simply re-parse the method for every
 729          * execution since there isn't much overhead (compared to keeping lots
 730          * of parse trees around)
 731          */
 732         acpi_ns_delete_namespace_subtree(node);
 733         acpi_ns_delete_namespace_by_owner(obj_desc->method.owner_id);
 734
 735       cleanup2:
 736         acpi_ut_release_owner_id(&obj_desc->method.owner_id);
 737
 738       cleanup:
 739         acpi_ps_delete_parse_tree(op);
 740         return_ACPI_STATUS(status);
 741 }
 742 #endif