drivers/acpi/acpica/dsmethod.c

   1 /******************************************************************************
   2  *
   3  * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2017, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46 #include "acdispat.h"
  47 #include "acinterp.h"
  48 #include "acnamesp.h"
  49 #include "acparser.h"
  50 #include "amlcode.h"
  51 #include "acdebug.h"
  52
  53 #define _COMPONENT          ACPI_DISPATCHER
  54 ACPI_MODULE_NAME("dsmethod")
  55
  56 /* Local prototypes */
  57 static acpi_status
  58 acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state,
  59                              union acpi_parse_object **out_op);
  60
  61 static acpi_status
  62 acpi_ds_create_method_mutex(union acpi_operand_object *method_desc);
  63
  64 /*******************************************************************************
  65  *
  66  * FUNCTION:    acpi_ds_auto_serialize_method
  67  *
  68  * PARAMETERS:  node                        - Namespace Node of the method
  69  *              obj_desc                    - Method object attached to node
  70  *
  71  * RETURN:      Status
  72  *
  73  * DESCRIPTION: Parse a control method AML to scan for control methods that
  74  *              need serialization due to the creation of named objects.
  75  *
  76  * NOTE: It is a bit of overkill to mark all such methods serialized, since
  77  * there is only a problem if the method actually blocks during execution.
  78  * A blocking operation is, for example, a Sleep() operation, or any access
  79  * to an operation region. However, it is probably not possible to easily
  80  * detect whether a method will block or not, so we simply mark all suspicious
  81  * methods as serialized.
  82  *
  83  * NOTE2: This code is essentially a generic routine for parsing a single
  84  * control method.
  85  *
  86  ******************************************************************************/
  87
  88 acpi_status
  89 acpi_ds_auto_serialize_method(struct acpi_namespace_node *node,
  90                               union acpi_operand_object *obj_desc)
  91 {
  92         acpi_status status;
  93         union acpi_parse_object *op = NULL;
  94         struct acpi_walk_state *walk_state;
  95
  96         ACPI_FUNCTION_TRACE_PTR(ds_auto_serialize_method, node);
  97
  98         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
  99                           "Method auto-serialization parse [%4.4s] %p\n",
 100                           acpi_ut_get_node_name(node), node));
 101
 102         /* Create/Init a root op for the method parse tree */
 103
 104         op = acpi_ps_alloc_op(AML_METHOD_OP, obj_desc->method.aml_start);
 105         if (!op) {
 106                 return_ACPI_STATUS(AE_NO_MEMORY);
 107         }
 108
 109         acpi_ps_set_name(op, node->name.integer);
 110         op->common.node = node;
 111
 112         /* Create and initialize a new walk state */
 113
 114         walk_state =
 115             acpi_ds_create_walk_state(node->owner_id, NULL, NULL, NULL);
 116         if (!walk_state) {
 117                 acpi_ps_free_op(op);
 118                 return_ACPI_STATUS(AE_NO_MEMORY);
 119         }
 120
 121         status = acpi_ds_init_aml_walk(walk_state, op, node,
 122                                        obj_desc->method.aml_start,
 123                                        obj_desc->method.aml_length, NULL, 0);
 124         if (ACPI_FAILURE(status)) {
 125                 acpi_ds_delete_walk_state(walk_state);
 126                 acpi_ps_free_op(op);
 127                 return_ACPI_STATUS(status);
 128         }
 129
 130         walk_state->descending_callback = acpi_ds_detect_named_opcodes;
 131
 132         /* Parse the method, scan for creation of named objects */
 133
 134         status = acpi_ps_parse_aml(walk_state);
 135
 136         acpi_ps_delete_parse_tree(op);
 137         return_ACPI_STATUS(status);
 138 }
 139
 140 /*******************************************************************************
 141  *
 142  * FUNCTION:    acpi_ds_detect_named_opcodes
 143  *
 144  * PARAMETERS:  walk_state      - Current state of the parse tree walk
 145  *              out_op          - Unused, required for parser interface
 146  *
 147  * RETURN:      Status
 148  *
 149  * DESCRIPTION: Descending callback used during the loading of ACPI tables.
 150  *              Currently used to detect methods that must be marked serialized
 151  *              in order to avoid problems with the creation of named objects.
 152  *
 153  ******************************************************************************/
 154
 155 static acpi_status
 156 acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state,
 157                              union acpi_parse_object **out_op)
 158 {
 159
 160         ACPI_FUNCTION_NAME(acpi_ds_detect_named_opcodes);
 161
 162         /* We are only interested in opcodes that create a new name */
 163
 164         if (!
 165             (walk_state->op_info->
 166              flags & (AML_NAMED | AML_CREATE | AML_FIELD))) {
 167                 return (AE_OK);
 168         }
 169
 170         /*
 171          * At this point, we know we have a Named object opcode.
 172          * Mark the method as serialized. Later code will create a mutex for
 173          * this method to enforce serialization.
 174          *
 175          * Note, ACPI_METHOD_IGNORE_SYNC_LEVEL flag means that we will ignore the
 176          * Sync Level mechanism for this method, even though it is now serialized.
 177          * Otherwise, there can be conflicts with existing ASL code that actually
 178          * uses sync levels.
 179          */
 180         walk_state->method_desc->method.sync_level = 0;
 181         walk_state->method_desc->method.info_flags |=
 182             (ACPI_METHOD_SERIALIZED | ACPI_METHOD_IGNORE_SYNC_LEVEL);
 183
 184         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 185                           "Method serialized [%4.4s] %p - [%s] (%4.4X)\n",
 186                           walk_state->method_node->name.ascii,
 187                           walk_state->method_node, walk_state->op_info->name,
 188                           walk_state->opcode));
 189
 190         /* Abort the parse, no need to examine this method any further */
 191
 192         return (AE_CTRL_TERMINATE);
 193 }
 194
 195 /*******************************************************************************
 196  *
 197  * FUNCTION:    acpi_ds_method_error
 198  *
 199  * PARAMETERS:  status          - Execution status
 200  *              walk_state      - Current state
 201  *
 202  * RETURN:      Status
 203  *
 204  * DESCRIPTION: Called on method error. Invoke the global exception handler if
 205  *              present, dump the method data if the debugger is configured
 206  *
 207  *              Note: Allows the exception handler to change the status code
 208  *
 209  ******************************************************************************/
 210
 211 acpi_status
 212 acpi_ds_method_error(acpi_status status, struct acpi_walk_state *walk_state)
 213 {
 214         u32 aml_offset;
 215         acpi_name name = 0;
 216
 217         ACPI_FUNCTION_ENTRY();
 218
 219         /* Ignore AE_OK and control exception codes */
 220
 221         if (ACPI_SUCCESS(status) || (status & AE_CODE_CONTROL)) {
 222                 return (status);
 223         }
 224
 225         /* Invoke the global exception handler */
 226
 227         if (acpi_gbl_exception_handler) {
 228
 229                 /* Exit the interpreter, allow handler to execute methods */
 230
 231                 acpi_ex_exit_interpreter();
 232
 233                 /*
 234                  * Handler can map the exception code to anything it wants, including
 235                  * AE_OK, in which case the executing method will not be aborted.
 236                  */
 237                 aml_offset = (u32)ACPI_PTR_DIFF(walk_state->aml,
 238                                                 walk_state->parser_state.
 239                                                 aml_start);
 240
 241                 if (walk_state->method_node) {
 242                         name = walk_state->method_node->name.integer;
 243                 } else if (walk_state->deferred_node) {
 244                         name = walk_state->deferred_node->name.integer;
 245                 }
 246
 247                 status = acpi_gbl_exception_handler(status, name,
 248                                                     walk_state->opcode,
 249                                                     aml_offset, NULL);
 250                 acpi_ex_enter_interpreter();
 251         }
 252
 253         acpi_ds_clear_implicit_return(walk_state);
 254
 255         if (ACPI_FAILURE(status)) {
 256                 acpi_ds_dump_method_stack(status, walk_state, walk_state->op);
 257
 258                 /* Display method locals/args if debugger is present */
 259
 260 #ifdef ACPI_DEBUGGER
 261                 acpi_db_dump_method_info(status, walk_state);
 262 #endif
 263         }
 264
 265         return (status);
 266 }
 267
 268 /*******************************************************************************
 269  *
 270  * FUNCTION:    acpi_ds_create_method_mutex
 271  *
 272  * PARAMETERS:  obj_desc            - The method object
 273  *
 274  * RETURN:      Status
 275  *
 276  * DESCRIPTION: Create a mutex object for a serialized control method
 277  *
 278  ******************************************************************************/
 279
 280 static acpi_status
 281 acpi_ds_create_method_mutex(union acpi_operand_object *method_desc)
 282 {
 283         union acpi_operand_object *mutex_desc;
 284         acpi_status status;
 285
 286         ACPI_FUNCTION_TRACE(ds_create_method_mutex);
 287
 288         /* Create the new mutex object */
 289
 290         mutex_desc = acpi_ut_create_internal_object(ACPI_TYPE_MUTEX);
 291         if (!mutex_desc) {
 292                 return_ACPI_STATUS(AE_NO_MEMORY);
 293         }
 294
 295         /* Create the actual OS Mutex */
 296
 297         status = acpi_os_create_mutex(&mutex_desc->mutex.os_mutex);
 298         if (ACPI_FAILURE(status)) {
 299                 acpi_ut_delete_object_desc(mutex_desc);
 300                 return_ACPI_STATUS(status);
 301         }
 302
 303         mutex_desc->mutex.sync_level = method_desc->method.sync_level;
 304         method_desc->method.mutex = mutex_desc;
 305         return_ACPI_STATUS(AE_OK);
 306 }
 307
 308 /*******************************************************************************
 309  *
 310  * FUNCTION:    acpi_ds_begin_method_execution
 311  *
 312  * PARAMETERS:  method_node         - Node of the method
 313  *              obj_desc            - The method object
 314  *              walk_state          - current state, NULL if not yet executing
 315  *                                    a method.
 316  *
 317  * RETURN:      Status
 318  *
 319  * DESCRIPTION: Prepare a method for execution. Parses the method if necessary,
 320  *              increments the thread count, and waits at the method semaphore
 321  *              for clearance to execute.
 322  *
 323  ******************************************************************************/
 324
 325 acpi_status
 326 acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
 327                                union acpi_operand_object *obj_desc,
 328                                struct acpi_walk_state *walk_state)
 329 {
 330         acpi_status status = AE_OK;
 331
 332         ACPI_FUNCTION_TRACE_PTR(ds_begin_method_execution, method_node);
 333
 334         if (!method_node) {
 335                 return_ACPI_STATUS(AE_NULL_ENTRY);
 336         }
 337
 338         acpi_ex_start_trace_method(method_node, obj_desc, walk_state);
 339
 340         /* Prevent wraparound of thread count */
 341
 342         if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {
 343                 ACPI_ERROR((AE_INFO,
 344                             "Method reached maximum reentrancy limit (255)"));
 345                 return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
 346         }
 347
 348         /*
 349          * If this method is serialized, we need to acquire the method mutex.
 350          */
 351         if (obj_desc->method.info_flags & ACPI_METHOD_SERIALIZED) {
 352                 /*
 353                  * Create a mutex for the method if it is defined to be Serialized
 354                  * and a mutex has not already been created. We defer the mutex creation
 355                  * until a method is actually executed, to minimize the object count
 356                  */
 357                 if (!obj_desc->method.mutex) {
 358                         status = acpi_ds_create_method_mutex(obj_desc);
 359                         if (ACPI_FAILURE(status)) {
 360                                 return_ACPI_STATUS(status);
 361                         }
 362                 }
 363
 364                 /*
 365                  * The current_sync_level (per-thread) must be less than or equal to
 366                  * the sync level of the method. This mechanism provides some
 367                  * deadlock prevention.
 368                  *
 369                  * If the method was auto-serialized, we just ignore the sync level
 370                  * mechanism, because auto-serialization of methods can interfere
 371                  * with ASL code that actually uses sync levels.
 372                  *
 373                  * Top-level method invocation has no walk state at this point
 374                  */
 375                 if (walk_state &&
 376                     (!(obj_desc->method.
 377                        info_flags & ACPI_METHOD_IGNORE_SYNC_LEVEL))
 378                     && (walk_state->thread->current_sync_level >
 379                         obj_desc->method.mutex->mutex.sync_level)) {
 380                         ACPI_ERROR((AE_INFO,
 381                                     "Cannot acquire Mutex for method [%4.4s]"
 382                                     ", current SyncLevel is too large (%u)",
 383                                     acpi_ut_get_node_name(method_node),
 384                                     walk_state->thread->current_sync_level));
 385
 386                         return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
 387                 }
 388
 389                 /*
 390                  * Obtain the method mutex if necessary. Do not acquire mutex for a
 391                  * recursive call.
 392                  */
 393                 if (!walk_state ||
 394                     !obj_desc->method.mutex->mutex.thread_id ||
 395                     (walk_state->thread->thread_id !=
 396                      obj_desc->method.mutex->mutex.thread_id)) {
 397                         /*
 398                          * Acquire the method mutex. This releases the interpreter if we
 399                          * block (and reacquires it before it returns)
 400                          */
 401                         status =
 402                             acpi_ex_system_wait_mutex(obj_desc->method.mutex->
 403                                                       mutex.os_mutex,
 404                                                       ACPI_WAIT_FOREVER);
 405                         if (ACPI_FAILURE(status)) {
 406                                 return_ACPI_STATUS(status);
 407                         }
 408
 409                         /* Update the mutex and walk info and save the original sync_level */
 410
 411                         if (walk_state) {
 412                                 obj_desc->method.mutex->mutex.
 413                                     original_sync_level =
 414                                     walk_state->thread->current_sync_level;
 415
 416                                 obj_desc->method.mutex->mutex.thread_id =
 417                                     walk_state->thread->thread_id;
 418
 419                                 /*
 420                                  * Update the current sync_level only if this is not an auto-
 421                                  * serialized method. In the auto case, we have to ignore
 422                                  * the sync level for the method mutex (created for the
 423                                  * auto-serialization) because we have no idea of what the
 424                                  * sync level should be. Therefore, just ignore it.
 425                                  */
 426                                 if (!(obj_desc->method.info_flags &
 427                                       ACPI_METHOD_IGNORE_SYNC_LEVEL)) {
 428                                         walk_state->thread->current_sync_level =
 429                                             obj_desc->method.sync_level;
 430                                 }
 431                         } else {
 432                                 obj_desc->method.mutex->mutex.
 433                                     original_sync_level =
 434                                     obj_desc->method.mutex->mutex.sync_level;
 435
 436                                 obj_desc->method.mutex->mutex.thread_id =
 437                                     acpi_os_get_thread_id();
 438                         }
 439                 }
 440
 441                 /* Always increase acquisition depth */
 442
 443                 obj_desc->method.mutex->mutex.acquisition_depth++;
 444         }
 445
 446         /*
 447          * Allocate an Owner ID for this method, only if this is the first thread
 448          * to begin concurrent execution. We only need one owner_id, even if the
 449          * method is invoked recursively.
 450          */
 451         if (!obj_desc->method.owner_id) {
 452                 status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
 453                 if (ACPI_FAILURE(status)) {
 454                         goto cleanup;
 455                 }
 456         }
 457
 458         /*
 459          * Increment the method parse tree thread count since it has been
 460          * reentered one more time (even if it is the same thread)
 461          */
 462         obj_desc->method.thread_count++;
 463         acpi_method_count++;
 464         return_ACPI_STATUS(status);
 465
 466 cleanup:
 467         /* On error, must release the method mutex (if present) */
 468
 469         if (obj_desc->method.mutex) {
 470                 acpi_os_release_mutex(obj_desc->method.mutex->mutex.os_mutex);
 471         }
 472         return_ACPI_STATUS(status);
 473 }
 474
 475 /*******************************************************************************
 476  *
 477  * FUNCTION:    acpi_ds_call_control_method
 478  *
 479  * PARAMETERS:  thread              - Info for this thread
 480  *              this_walk_state     - Current walk state
 481  *              op                  - Current Op to be walked
 482  *
 483  * RETURN:      Status
 484  *
 485  * DESCRIPTION: Transfer execution to a called control method
 486  *
 487  ******************************************************************************/
 488
 489 acpi_status
 490 acpi_ds_call_control_method(struct acpi_thread_state *thread,
 491                             struct acpi_walk_state *this_walk_state,
 492                             union acpi_parse_object *op)
 493 {
 494         acpi_status status;
 495         struct acpi_namespace_node *method_node;
 496         struct acpi_walk_state *next_walk_state = NULL;
 497         union acpi_operand_object *obj_desc;
 498         struct acpi_evaluate_info *info;
 499         u32 i;
 500
 501         ACPI_FUNCTION_TRACE_PTR(ds_call_control_method, this_walk_state);
 502
 503         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 504                           "Calling method %p, currentstate=%p\n",
 505                           this_walk_state->prev_op, this_walk_state));
 506
 507         /*
 508          * Get the namespace entry for the control method we are about to call
 509          */
 510         method_node = this_walk_state->method_call_node;
 511         if (!method_node) {
 512                 return_ACPI_STATUS(AE_NULL_ENTRY);
 513         }
 514
 515         obj_desc = acpi_ns_get_attached_object(method_node);
 516         if (!obj_desc) {
 517                 return_ACPI_STATUS(AE_NULL_OBJECT);
 518         }
 519
 520         /* Init for new method, possibly wait on method mutex */
 521
 522         status =
 523             acpi_ds_begin_method_execution(method_node, obj_desc,
 524                                            this_walk_state);
 525         if (ACPI_FAILURE(status)) {
 526                 return_ACPI_STATUS(status);
 527         }
 528
 529         /* Begin method parse/execution. Create a new walk state */
 530
 531         next_walk_state =
 532             acpi_ds_create_walk_state(obj_desc->method.owner_id, NULL, obj_desc,
 533                                       thread);
 534         if (!next_walk_state) {
 535                 status = AE_NO_MEMORY;
 536                 goto cleanup;
 537         }
 538
 539         /*
 540          * The resolved arguments were put on the previous walk state's operand
 541          * stack. Operands on the previous walk state stack always
 542          * start at index 0. Also, null terminate the list of arguments
 543          */
 544         this_walk_state->operands[this_walk_state->num_operands] = NULL;
 545
 546         /*
 547          * Allocate and initialize the evaluation information block
 548          * TBD: this is somewhat inefficient, should change interface to
 549          * ds_init_aml_walk. For now, keeps this struct off the CPU stack
 550          */
 551         info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
 552         if (!info) {
 553                 status = AE_NO_MEMORY;
 554                 goto pop_walk_state;
 555         }
 556
 557         info->parameters = &this_walk_state->operands[0];
 558
 559         status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
 560                                        obj_desc->method.aml_start,
 561                                        obj_desc->method.aml_length, info,
 562                                        ACPI_IMODE_EXECUTE);
 563
 564         ACPI_FREE(info);
 565         if (ACPI_FAILURE(status)) {
 566                 goto pop_walk_state;
 567         }
 568
 569         /*
 570          * Delete the operands on the previous walkstate operand stack
 571          * (they were copied to new objects)
 572          */
 573         for (i = 0; i < obj_desc->method.param_count; i++) {
 574                 acpi_ut_remove_reference(this_walk_state->operands[i]);
 575                 this_walk_state->operands[i] = NULL;
 576         }
 577
 578         /* Clear the operand stack */
 579
 580         this_walk_state->num_operands = 0;
 581
 582         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 583                           "**** Begin nested execution of [%4.4s] **** WalkState=%p\n",
 584                           method_node->name.ascii, next_walk_state));
 585
 586         /* Invoke an internal method if necessary */
 587
 588         if (obj_desc->method.info_flags & ACPI_METHOD_INTERNAL_ONLY) {
 589                 status =
 590                     obj_desc->method.dispatch.implementation(next_walk_state);
 591                 if (status == AE_OK) {
 592                         status = AE_CTRL_TERMINATE;
 593                 }
 594         }
 595
 596         return_ACPI_STATUS(status);
 597
 598 pop_walk_state:
 599
 600         /* On error, pop the walk state to be deleted from thread */
 601
 602         acpi_ds_pop_walk_state(thread);
 603
 604 cleanup:
 605
 606         /* On error, we must terminate the method properly */
 607
 608         acpi_ds_terminate_control_method(obj_desc, next_walk_state);
 609         acpi_ds_delete_walk_state(next_walk_state);
 610
 611         return_ACPI_STATUS(status);
 612 }
 613
 614 /*******************************************************************************
 615  *
 616  * FUNCTION:    acpi_ds_restart_control_method
 617  *
 618  * PARAMETERS:  walk_state          - State for preempted method (caller)
 619  *              return_desc         - Return value from the called method
 620  *
 621  * RETURN:      Status
 622  *
 623  * DESCRIPTION: Restart a method that was preempted by another (nested) method
 624  *              invocation. Handle the return value (if any) from the callee.
 625  *
 626  ******************************************************************************/
 627
 628 acpi_status
 629 acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
 630                                union acpi_operand_object *return_desc)
 631 {
 632         acpi_status status;
 633         int same_as_implicit_return;
 634
 635         ACPI_FUNCTION_TRACE_PTR(ds_restart_control_method, walk_state);
 636
 637         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 638                           "****Restart [%4.4s] Op %p ReturnValueFromCallee %p\n",
 639                           acpi_ut_get_node_name(walk_state->method_node),
 640                           walk_state->method_call_op, return_desc));
 641
 642         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 643                           "    ReturnFromThisMethodUsed?=%X ResStack %p Walk %p\n",
 644                           walk_state->return_used,
 645                           walk_state->results, walk_state));
 646
 647         /* Did the called method return a value? */
 648
 649         if (return_desc) {
 650
 651                 /* Is the implicit return object the same as the return desc? */
 652
 653                 same_as_implicit_return =
 654                     (walk_state->implicit_return_obj == return_desc);
 655
 656                 /* Are we actually going to use the return value? */
 657
 658                 if (walk_state->return_used) {
 659
 660                         /* Save the return value from the previous method */
 661
 662                         status = acpi_ds_result_push(return_desc, walk_state);
 663                         if (ACPI_FAILURE(status)) {
 664                                 acpi_ut_remove_reference(return_desc);
 665                                 return_ACPI_STATUS(status);
 666                         }
 667
 668                         /*
 669                          * Save as THIS method's return value in case it is returned
 670                          * immediately to yet another method
 671                          */
 672                         walk_state->return_desc = return_desc;
 673                 }
 674
 675                 /*
 676                  * The following code is the optional support for the so-called
 677                  * "implicit return". Some AML code assumes that the last value of the
 678                  * method is "implicitly" returned to the caller, in the absence of an
 679                  * explicit return value.
 680                  *
 681                  * Just save the last result of the method as the return value.
 682                  *
 683                  * NOTE: this is optional because the ASL language does not actually
 684                  * support this behavior.
 685                  */
 686                 else if (!acpi_ds_do_implicit_return
 687                          (return_desc, walk_state, FALSE)
 688                          || same_as_implicit_return) {
 689                         /*
 690                          * Delete the return value if it will not be used by the
 691                          * calling method or remove one reference if the explicit return
 692                          * is the same as the implicit return value.
 693                          */
 694                         acpi_ut_remove_reference(return_desc);
 695                 }
 696         }
 697
 698         return_ACPI_STATUS(AE_OK);
 699 }
 700
 701 /*******************************************************************************
 702  *
 703  * FUNCTION:    acpi_ds_terminate_control_method
 704  *
 705  * PARAMETERS:  method_desc         - Method object
 706  *              walk_state          - State associated with the method
 707  *
 708  * RETURN:      None
 709  *
 710  * DESCRIPTION: Terminate a control method. Delete everything that the method
 711  *              created, delete all locals and arguments, and delete the parse
 712  *              tree if requested.
 713  *
 714  * MUTEX:       Interpreter is locked
 715  *
 716  ******************************************************************************/
 717
 718 void
 719 acpi_ds_terminate_control_method(union acpi_operand_object *method_desc,
 720                                  struct acpi_walk_state *walk_state)
 721 {
 722
 723         ACPI_FUNCTION_TRACE_PTR(ds_terminate_control_method, walk_state);
 724
 725         /* method_desc is required, walk_state is optional */
 726
 727         if (!method_desc) {
 728                 return_VOID;
 729         }
 730
 731         if (walk_state) {
 732
 733                 /* Delete all arguments and locals */
 734
 735                 acpi_ds_method_data_delete_all(walk_state);
 736
 737                 /*
 738                  * Delete any namespace objects created anywhere within the
 739                  * namespace by the execution of this method. Unless:
 740                  * 1) This method is a module-level executable code method, in which
 741                  *    case we want make the objects permanent.
 742                  * 2) There are other threads executing the method, in which case we
 743                  *    will wait until the last thread has completed.
 744                  */
 745                 if (!(method_desc->method.info_flags & ACPI_METHOD_MODULE_LEVEL)
 746                     && (method_desc->method.thread_count == 1)) {
 747
 748                         /* Delete any direct children of (created by) this method */
 749
 750                         (void)acpi_ex_exit_interpreter();
 751                         acpi_ns_delete_namespace_subtree(walk_state->
 752                                                          method_node);
 753                         (void)acpi_ex_enter_interpreter();
 754
 755                         /*
 756                          * Delete any objects that were created by this method
 757                          * elsewhere in the namespace (if any were created).
 758                          * Use of the ACPI_METHOD_MODIFIED_NAMESPACE optimizes the
 759                          * deletion such that we don't have to perform an entire
 760                          * namespace walk for every control method execution.
 761                          */
 762                         if (method_desc->method.
 763                             info_flags & ACPI_METHOD_MODIFIED_NAMESPACE) {
 764                                 (void)acpi_ex_exit_interpreter();
 765                                 acpi_ns_delete_namespace_by_owner(method_desc->
 766                                                                   method.
 767                                                                   owner_id);
 768                                 (void)acpi_ex_enter_interpreter();
 769                                 method_desc->method.info_flags &=
 770                                     ~ACPI_METHOD_MODIFIED_NAMESPACE;
 771                         }
 772                 }
 773
 774                 /*
 775                  * If method is serialized, release the mutex and restore the
 776                  * current sync level for this thread
 777                  */
 778                 if (method_desc->method.mutex) {
 779
 780                         /* Acquisition Depth handles recursive calls */
 781
 782                         method_desc->method.mutex->mutex.acquisition_depth--;
 783                         if (!method_desc->method.mutex->mutex.acquisition_depth) {
 784                                 walk_state->thread->current_sync_level =
 785                                     method_desc->method.mutex->mutex.
 786                                     original_sync_level;
 787
 788                                 acpi_os_release_mutex(method_desc->method.
 789                                                       mutex->mutex.os_mutex);
 790                                 method_desc->method.mutex->mutex.thread_id = 0;
 791                         }
 792                 }
 793         }
 794
 795         /* Decrement the thread count on the method */
 796
 797         if (method_desc->method.thread_count) {
 798                 method_desc->method.thread_count--;
 799         } else {
 800                 ACPI_ERROR((AE_INFO, "Invalid zero thread count in method"));
 801         }
 802
 803         /* Are there any other threads currently executing this method? */
 804
 805         if (method_desc->method.thread_count) {
 806                 /*
 807                  * Additional threads. Do not release the owner_id in this case,
 808                  * we immediately reuse it for the next thread executing this method
 809                  */
 810                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 811                                   "*** Completed execution of one thread, %u threads remaining\n",
 812                                   method_desc->method.thread_count));
 813         } else {
 814                 /* This is the only executing thread for this method */
 815
 816                 /*
 817                  * Support to dynamically change a method from not_serialized to
 818                  * Serialized if it appears that the method is incorrectly written and
 819                  * does not support multiple thread execution. The best example of this
 820                  * is if such a method creates namespace objects and blocks. A second
 821                  * thread will fail with an AE_ALREADY_EXISTS exception.
 822                  *
 823                  * This code is here because we must wait until the last thread exits
 824                  * before marking the method as serialized.
 825                  */
 826                 if (method_desc->method.
 827                     info_flags & ACPI_METHOD_SERIALIZED_PENDING) {
 828                         if (walk_state) {
 829                                 ACPI_INFO(("Marking method %4.4s as Serialized "
 830                                            "because of AE_ALREADY_EXISTS error",
 831                                            walk_state->method_node->name.
 832                                            ascii));
 833                         }
 834
 835                         /*
 836                          * Method tried to create an object twice and was marked as
 837                          * "pending serialized". The probable cause is that the method
 838                          * cannot handle reentrancy.
 839                          *
 840                          * The method was created as not_serialized, but it tried to create
 841                          * a named object and then blocked, causing the second thread
 842                          * entrance to begin and then fail. Workaround this problem by
 843                          * marking the method permanently as Serialized when the last
 844                          * thread exits here.
 845                          */
 846                         method_desc->method.info_flags &=
 847                             ~ACPI_METHOD_SERIALIZED_PENDING;
 848
 849                         method_desc->method.info_flags |=
 850                             (ACPI_METHOD_SERIALIZED |
 851                              ACPI_METHOD_IGNORE_SYNC_LEVEL);
 852                         method_desc->method.sync_level = 0;
 853                 }
 854
 855                 /* No more threads, we can free the owner_id */
 856
 857                 if (!
 858                     (method_desc->method.
 859                      info_flags & ACPI_METHOD_MODULE_LEVEL)) {
 860                         acpi_ut_release_owner_id(&method_desc->method.owner_id);
 861                 }
 862         }
 863
 864         acpi_ex_stop_trace_method((struct acpi_namespace_node *)method_desc->
 865                                   method.node, method_desc, walk_state);
 866
 867         return_VOID;
 868 }