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