git.oblomov.eu Git - linux-2.6/blob - 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
 174                  */
 175                 status =
 176                     acpi_ex_system_wait_semaphore(obj_desc->method.semaphore,
 177                                                   ACPI_WAIT_FOREVER);
 178         }
 179
 180         /*
 181          * Allocate an Owner ID for this method, only if this is the first thread
 182          * to begin concurrent execution. We only need one owner_id, even if the
 183          * method is invoked recursively.
 184          */
 185         if (!obj_desc->method.owner_id) {
 186                 status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
 187                 if (ACPI_FAILURE(status)) {
 188                         return_ACPI_STATUS(status);
 189                 }
 190         }
 191
 192         /*
 193          * Increment the method parse tree thread count since it has been
 194          * reentered one more time (even if it is the same thread)
 195          */
 196         obj_desc->method.thread_count++;
 197         return_ACPI_STATUS(status);
 198 }
 199
 200 /*******************************************************************************
 201  *
 202  * FUNCTION:    acpi_ds_call_control_method
 203  *
 204  * PARAMETERS:  Thread              - Info for this thread
 205  *              this_walk_state     - Current walk state
 206  *              Op                  - Current Op to be walked
 207  *
 208  * RETURN:      Status
 209  *
 210  * DESCRIPTION: Transfer execution to a called control method
 211  *
 212  ******************************************************************************/
 213
 214 acpi_status
 215 acpi_ds_call_control_method(struct acpi_thread_state *thread,
 216                             struct acpi_walk_state *this_walk_state,
 217                             union acpi_parse_object *op)
 218 {
 219         acpi_status status;
 220         struct acpi_namespace_node *method_node;
 221         struct acpi_walk_state *next_walk_state = NULL;
 222         union acpi_operand_object *obj_desc;
 223         struct acpi_parameter_info info;
 224         u32 i;
 225
 226         ACPI_FUNCTION_TRACE_PTR("ds_call_control_method", this_walk_state);
 227
 228         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 229                           "Execute method %p, currentstate=%p\n",
 230                           this_walk_state->prev_op, this_walk_state));
 231
 232         /*
 233          * Get the namespace entry for the control method we are about to call
 234          */
 235         method_node = this_walk_state->method_call_node;
 236         if (!method_node) {
 237                 return_ACPI_STATUS(AE_NULL_ENTRY);
 238         }
 239
 240         obj_desc = acpi_ns_get_attached_object(method_node);
 241         if (!obj_desc) {
 242                 return_ACPI_STATUS(AE_NULL_OBJECT);
 243         }
 244
 245         /* Init for new method, wait on concurrency semaphore */
 246
 247         status = acpi_ds_begin_method_execution(method_node, obj_desc,
 248                                                 this_walk_state->method_node);
 249         if (ACPI_FAILURE(status)) {
 250                 goto cleanup;
 251         }
 252
 253         if (!(obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY)) {
 254
 255                 /* 1) Parse: Create a new walk state for the preempting walk */
 256
 257                 next_walk_state =
 258                     acpi_ds_create_walk_state(obj_desc->method.owner_id, op,
 259                                               obj_desc, NULL);
 260                 if (!next_walk_state) {
 261                         return_ACPI_STATUS(AE_NO_MEMORY);
 262                 }
 263
 264                 /* Create and init a Root Node */
 265
 266                 op = acpi_ps_create_scope_op();
 267                 if (!op) {
 268                         status = AE_NO_MEMORY;
 269                         goto cleanup;
 270                 }
 271
 272                 status = acpi_ds_init_aml_walk(next_walk_state, op, method_node,
 273                                                obj_desc->method.aml_start,
 274                                                obj_desc->method.aml_length,
 275                                                NULL, 1);
 276                 if (ACPI_FAILURE(status)) {
 277                         acpi_ds_delete_walk_state(next_walk_state);
 278                         goto cleanup;
 279                 }
 280
 281                 /* Begin AML parse */
 282
 283                 status = acpi_ps_parse_aml(next_walk_state);
 284                 acpi_ps_delete_parse_tree(op);
 285         }
 286
 287         /* 2) Execute: Create a new state for the preempting walk */
 288
 289         next_walk_state = acpi_ds_create_walk_state(obj_desc->method.owner_id,
 290                                                     NULL, obj_desc, thread);
 291         if (!next_walk_state) {
 292                 status = AE_NO_MEMORY;
 293                 goto cleanup;
 294         }
 295         /*
 296          * The resolved arguments were put on the previous walk state's operand
 297          * stack. Operands on the previous walk state stack always
 298          * start at index 0. Also, null terminate the list of arguments
 299          */
 300         this_walk_state->operands[this_walk_state->num_operands] = NULL;
 301
 302         info.parameters = &this_walk_state->operands[0];
 303         info.parameter_type = ACPI_PARAM_ARGS;
 304
 305         status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
 306                                        obj_desc->method.aml_start,
 307                                        obj_desc->method.aml_length, &info, 3);
 308         if (ACPI_FAILURE(status)) {
 309                 goto cleanup;
 310         }
 311
 312         /*
 313          * Delete the operands on the previous walkstate operand stack
 314          * (they were copied to new objects)
 315          */
 316         for (i = 0; i < obj_desc->method.param_count; i++) {
 317                 acpi_ut_remove_reference(this_walk_state->operands[i]);
 318                 this_walk_state->operands[i] = NULL;
 319         }
 320
 321         /* Clear the operand stack */
 322
 323         this_walk_state->num_operands = 0;
 324
 325         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 326                           "Starting nested execution, newstate=%p\n",
 327                           next_walk_state));
 328
 329         if (obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY) {
 330                 status = obj_desc->method.implementation(next_walk_state);
 331         }
 332
 333         return_ACPI_STATUS(status);
 334
 335       cleanup:
 336         /* Decrement the thread count on the method parse tree */
 337
 338         if (next_walk_state && (next_walk_state->method_desc)) {
 339                 next_walk_state->method_desc->method.thread_count--;
 340         }
 341
 342         /* On error, we must delete the new walk state */
 343
 344         acpi_ds_terminate_control_method(next_walk_state);
 345         acpi_ds_delete_walk_state(next_walk_state);
 346         return_ACPI_STATUS(status);
 347 }
 348
 349 /*******************************************************************************
 350  *
 351  * FUNCTION:    acpi_ds_restart_control_method
 352  *
 353  * PARAMETERS:  walk_state          - State for preempted method (caller)
 354  *              return_desc         - Return value from the called method
 355  *
 356  * RETURN:      Status
 357  *
 358  * DESCRIPTION: Restart a method that was preempted by another (nested) method
 359  *              invocation.  Handle the return value (if any) from the callee.
 360  *
 361  ******************************************************************************/
 362
 363 acpi_status
 364 acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
 365                                union acpi_operand_object *return_desc)
 366 {
 367         acpi_status status;
 368
 369         ACPI_FUNCTION_TRACE_PTR("ds_restart_control_method", walk_state);
 370
 371         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 372                           "****Restart [%4.4s] Op %p return_value_from_callee %p\n",
 373                           (char *)&walk_state->method_node->name,
 374                           walk_state->method_call_op, return_desc));
 375
 376         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 377                           "    return_from_this_method_used?=%X res_stack %p Walk %p\n",
 378                           walk_state->return_used,
 379                           walk_state->results, walk_state));
 380
 381         /* Did the called method return a value? */
 382
 383         if (return_desc) {
 384
 385                 /* Are we actually going to use the return value? */
 386
 387                 if (walk_state->return_used) {
 388
 389                         /* Save the return value from the previous method */
 390
 391                         status = acpi_ds_result_push(return_desc, walk_state);
 392                         if (ACPI_FAILURE(status)) {
 393                                 acpi_ut_remove_reference(return_desc);
 394                                 return_ACPI_STATUS(status);
 395                         }
 396
 397                         /*
 398                          * Save as THIS method's return value in case it is returned
 399                          * immediately to yet another method
 400                          */
 401                         walk_state->return_desc = return_desc;
 402                 }
 403
 404                 /*
 405                  * The following code is the
 406                  * optional support for a so-called "implicit return". Some AML code
 407                  * assumes that the last value of the method is "implicitly" returned
 408                  * to the caller. Just save the last result as the return value.
 409                  * NOTE: this is optional because the ASL language does not actually
 410                  * support this behavior.
 411                  */
 412                 else if (!acpi_ds_do_implicit_return
 413                          (return_desc, walk_state, FALSE)) {
 414                         /*
 415                          * Delete the return value if it will not be used by the
 416                          * calling method
 417                          */
 418                         acpi_ut_remove_reference(return_desc);
 419                 }
 420         }
 421
 422         return_ACPI_STATUS(AE_OK);
 423 }
 424
 425 /*******************************************************************************
 426  *
 427  * FUNCTION:    acpi_ds_terminate_control_method
 428  *
 429  * PARAMETERS:  walk_state          - State of the method
 430  *
 431  * RETURN:      None
 432  *
 433  * DESCRIPTION: Terminate a control method.  Delete everything that the method
 434  *              created, delete all locals and arguments, and delete the parse
 435  *              tree if requested.
 436  *
 437  ******************************************************************************/
 438
 439 void acpi_ds_terminate_control_method(struct acpi_walk_state *walk_state)
 440 {
 441         union acpi_operand_object *obj_desc;
 442         struct acpi_namespace_node *method_node;
 443         acpi_status status;
 444
 445         ACPI_FUNCTION_TRACE_PTR("ds_terminate_control_method", walk_state);
 446
 447         if (!walk_state) {
 448                 return_VOID;
 449         }
 450
 451         /* The current method object was saved in the walk state */
 452
 453         obj_desc = walk_state->method_desc;
 454         if (!obj_desc) {
 455                 return_VOID;
 456         }
 457
 458         /* Delete all arguments and locals */
 459
 460         acpi_ds_method_data_delete_all(walk_state);
 461
 462         /*
 463          * Lock the parser while we terminate this method.
 464          * If this is the last thread executing the method,
 465          * we have additional cleanup to perform
 466          */
 467         status = acpi_ut_acquire_mutex(ACPI_MTX_PARSER);
 468         if (ACPI_FAILURE(status)) {
 469                 return_VOID;
 470         }
 471
 472         /* Signal completion of the execution of this method if necessary */
 473
 474         if (walk_state->method_desc->method.semaphore) {
 475                 status =
 476                     acpi_os_signal_semaphore(walk_state->method_desc->method.
 477                                              semaphore, 1);
 478                 if (ACPI_FAILURE(status)) {
 479                         ACPI_ERROR((AE_INFO,
 480                                     "Could not signal method semaphore"));
 481
 482                         /* Ignore error and continue cleanup */
 483                 }
 484         }
 485
 486         /*
 487          * There are no more threads executing this method.  Perform
 488          * additional cleanup.
 489          *
 490          * The method Node is stored in the walk state
 491          */
 492         method_node = walk_state->method_node;
 493
 494         /* Lock namespace for possible update */
 495
 496         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 497         if (ACPI_FAILURE(status)) {
 498                 goto exit;
 499         }
 500
 501         /*
 502          * Delete any namespace entries created immediately underneath
 503          * the method
 504          */
 505         if (method_node->child) {
 506                 acpi_ns_delete_namespace_subtree(method_node);
 507         }
 508
 509         /*
 510          * Delete any namespace entries created anywhere else within
 511          * the namespace by the execution of this method
 512          */
 513         acpi_ns_delete_namespace_by_owner(walk_state->method_desc->method.
 514                                           owner_id);
 515         status = acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 516
 517         /* Are there any other threads currently executing this method? */
 518
 519         if (walk_state->method_desc->method.thread_count) {
 520                 /*
 521                  * Additional threads. Do not release the owner_id in this case,
 522                  * we immediately reuse it for the next thread executing this method
 523                  */
 524                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 525                                   "*** Completed execution of one thread, %d threads remaining\n",
 526                                   walk_state->method_desc->method.
 527                                   thread_count));
 528         } else {
 529                 /* This is the only executing thread for this method */
 530
 531                 /*
 532                  * Support to dynamically change a method from not_serialized to
 533                  * Serialized if it appears that the method is incorrectly written and
 534                  * does not support multiple thread execution.  The best example of this
 535                  * is if such a method creates namespace objects and blocks.  A second
 536                  * thread will fail with an AE_ALREADY_EXISTS exception
 537                  *
 538                  * This code is here because we must wait until the last thread exits
 539                  * before creating the synchronization semaphore.
 540                  */
 541                 if ((walk_state->method_desc->method.concurrency == 1) &&
 542                     (!walk_state->method_desc->method.semaphore)) {
 543                         status = acpi_os_create_semaphore(1, 1,
 544                                                           &walk_state->
 545                                                           method_desc->method.
 546                                                           semaphore);
 547                 }
 548
 549                 /* No more threads, we can free the owner_id */
 550
 551                 acpi_ut_release_owner_id(&walk_state->method_desc->method.
 552                                          owner_id);
 553         }
 554
 555       exit:
 556         (void)acpi_ut_release_mutex(ACPI_MTX_PARSER);
 557         return_VOID;
 558 }
 559
 560 #ifdef ACPI_INIT_PARSE_METHODS
 561         /*
 562          * Note 11/2005: Removed this code to parse all methods during table
 563          * load because it causes problems if there are any errors during the
 564          * parse. Also, it seems like overkill and we probably don't want to
 565          * abort a table load because of an issue with a single method.
 566          */
 567
 568 /*******************************************************************************
 569  *
 570  * FUNCTION:    acpi_ds_parse_method
 571  *
 572  * PARAMETERS:  Node        - Method node
 573  *
 574  * RETURN:      Status
 575  *
 576  * DESCRIPTION: Parse the AML that is associated with the method.
 577  *
 578  * MUTEX:       Assumes parser is locked
 579  *
 580  ******************************************************************************/
 581
 582 acpi_status acpi_ds_parse_method(struct acpi_namespace_node *node)
 583 {
 584         acpi_status status;
 585         union acpi_operand_object *obj_desc;
 586         union acpi_parse_object *op;
 587         struct acpi_walk_state *walk_state;
 588
 589         ACPI_FUNCTION_TRACE_PTR("ds_parse_method", node);
 590
 591         /* Parameter Validation */
 592
 593         if (!node) {
 594                 return_ACPI_STATUS(AE_NULL_ENTRY);
 595         }
 596
 597         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 598                           "**** Parsing [%4.4s] **** named_obj=%p\n",
 599                           acpi_ut_get_node_name(node), node));
 600
 601         /* Extract the method object from the method Node */
 602
 603         obj_desc = acpi_ns_get_attached_object(node);
 604         if (!obj_desc) {
 605                 return_ACPI_STATUS(AE_NULL_OBJECT);
 606         }
 607
 608         /* Create a mutex for the method if there is a concurrency limit */
 609
 610         if ((obj_desc->method.concurrency != ACPI_INFINITE_CONCURRENCY) &&
 611             (!obj_desc->method.semaphore)) {
 612                 status = acpi_os_create_semaphore(obj_desc->method.concurrency,
 613                                                   obj_desc->method.concurrency,
 614                                                   &obj_desc->method.semaphore);
 615                 if (ACPI_FAILURE(status)) {
 616                         return_ACPI_STATUS(status);
 617                 }
 618         }
 619
 620         /*
 621          * Allocate a new parser op to be the root of the parsed
 622          * method tree
 623          */
 624         op = acpi_ps_alloc_op(AML_METHOD_OP);
 625         if (!op) {
 626                 return_ACPI_STATUS(AE_NO_MEMORY);
 627         }
 628
 629         /* Init new op with the method name and pointer back to the Node */
 630
 631         acpi_ps_set_name(op, node->name.integer);
 632         op->common.node = node;
 633
 634         /*
 635          * Get a new owner_id for objects created by this method. Namespace
 636          * objects (such as Operation Regions) can be created during the
 637          * first pass parse.
 638          */
 639         status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
 640         if (ACPI_FAILURE(status)) {
 641                 goto cleanup;
 642         }
 643
 644         /* Create and initialize a new walk state */
 645
 646         walk_state =
 647             acpi_ds_create_walk_state(obj_desc->method.owner_id, NULL, NULL,
 648                                       NULL);
 649         if (!walk_state) {
 650                 status = AE_NO_MEMORY;
 651                 goto cleanup2;
 652         }
 653
 654         status = acpi_ds_init_aml_walk(walk_state, op, node,
 655                                        obj_desc->method.aml_start,
 656                                        obj_desc->method.aml_length, NULL, 1);
 657         if (ACPI_FAILURE(status)) {
 658                 acpi_ds_delete_walk_state(walk_state);
 659                 goto cleanup2;
 660         }
 661
 662         /*
 663          * Parse the method, first pass
 664          *
 665          * The first pass load is where newly declared named objects are added into
 666          * the namespace.  Actual evaluation of the named objects (what would be
 667          * called a "second pass") happens during the actual execution of the
 668          * method so that operands to the named objects can take on dynamic
 669          * run-time values.
 670          */
 671         status = acpi_ps_parse_aml(walk_state);
 672         if (ACPI_FAILURE(status)) {
 673                 goto cleanup2;
 674         }
 675
 676         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 677                           "**** [%4.4s] Parsed **** named_obj=%p Op=%p\n",
 678                           acpi_ut_get_node_name(node), node, op));
 679
 680         /*
 681          * Delete the parse tree. We simply re-parse the method for every
 682          * execution since there isn't much overhead (compared to keeping lots
 683          * of parse trees around)
 684          */
 685         acpi_ns_delete_namespace_subtree(node);
 686         acpi_ns_delete_namespace_by_owner(obj_desc->method.owner_id);
 687
 688       cleanup2:
 689         acpi_ut_release_owner_id(&obj_desc->method.owner_id);
 690
 691       cleanup:
 692         acpi_ps_delete_parse_tree(op);
 693         return_ACPI_STATUS(status);
 694 }
 695 #endif