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 - 2015, 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 #ifdef  ACPI_DISASSEMBLER
  50 #include "acdisasm.h"
  51 #endif
  52 #include "acparser.h"
  53 #include "amlcode.h"
  54
  55 #define _COMPONENT          ACPI_DISPATCHER
  56 ACPI_MODULE_NAME("dsmethod")
  57
  58 /* Local prototypes */
  59 static acpi_status
  60 acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state,
  61                              union acpi_parse_object **out_op);
  62
  63 static acpi_status
  64 acpi_ds_create_method_mutex(union acpi_operand_object *method_desc);
  65
  66 /*******************************************************************************
  67  *
  68  * FUNCTION:    acpi_ds_auto_serialize_method
  69  *
  70  * PARAMETERS:  node                        - Namespace Node of the method
  71  *              obj_desc                    - Method object attached to node
  72  *
  73  * RETURN:      Status
  74  *
  75  * DESCRIPTION: Parse a control method AML to scan for control methods that
  76  *              need serialization due to the creation of named objects.
  77  *
  78  * NOTE: It is a bit of overkill to mark all such methods serialized, since
  79  * there is only a problem if the method actually blocks during execution.
  80  * A blocking operation is, for example, a Sleep() operation, or any access
  81  * to an operation region. However, it is probably not possible to easily
  82  * detect whether a method will block or not, so we simply mark all suspicious
  83  * methods as serialized.
  84  *
  85  * NOTE2: This code is essentially a generic routine for parsing a single
  86  * control method.
  87  *
  88  ******************************************************************************/
  89
  90 acpi_status
  91 acpi_ds_auto_serialize_method(struct acpi_namespace_node *node,
  92                               union acpi_operand_object *obj_desc)
  93 {
  94         acpi_status status;
  95         union acpi_parse_object *op = NULL;
  96         struct acpi_walk_state *walk_state;
  97
  98         ACPI_FUNCTION_TRACE_PTR(ds_auto_serialize_method, node);
  99
 100         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 101                           "Method auto-serialization parse [%4.4s] %p\n",
 102                           acpi_ut_get_node_name(node), node));
 103
 104         /* Create/Init a root op for the method parse tree */
 105
 106         op = acpi_ps_alloc_op(AML_METHOD_OP, obj_desc->method.aml_start);
 107         if (!op) {
 108                 return_ACPI_STATUS(AE_NO_MEMORY);
 109         }
 110
 111         acpi_ps_set_name(op, node->name.integer);
 112         op->common.node = node;
 113
 114         /* Create and initialize a new walk state */
 115
 116         walk_state =
 117             acpi_ds_create_walk_state(node->owner_id, NULL, NULL, NULL);
 118         if (!walk_state) {
 119                 acpi_ps_free_op(op);
 120                 return_ACPI_STATUS(AE_NO_MEMORY);
 121         }
 122
 123         status =
 124             acpi_ds_init_aml_walk(walk_state, op, node,
 125                                   obj_desc->method.aml_start,
 126                                   obj_desc->method.aml_length, NULL, 0);
 127         if (ACPI_FAILURE(status)) {
 128                 acpi_ds_delete_walk_state(walk_state);
 129                 acpi_ps_free_op(op);
 130                 return_ACPI_STATUS(status);
 131         }
 132
 133         walk_state->descending_callback = acpi_ds_detect_named_opcodes;
 134
 135         /* Parse the method, scan for creation of named objects */
 136
 137         status = acpi_ps_parse_aml(walk_state);
 138
 139         acpi_ps_delete_parse_tree(op);
 140         return_ACPI_STATUS(status);
 141 }
 142
 143 /*******************************************************************************
 144  *
 145  * FUNCTION:    acpi_ds_detect_named_opcodes
 146  *
 147  * PARAMETERS:  walk_state      - Current state of the parse tree walk
 148  *              out_op          - Unused, required for parser interface
 149  *
 150  * RETURN:      Status
 151  *
 152  * DESCRIPTION: Descending callback used during the loading of ACPI tables.
 153  *              Currently used to detect methods that must be marked serialized
 154  *              in order to avoid problems with the creation of named objects.
 155  *
 156  ******************************************************************************/
 157
 158 static acpi_status
 159 acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state,
 160                              union acpi_parse_object **out_op)
 161 {
 162
 163         ACPI_FUNCTION_NAME(acpi_ds_detect_named_opcodes);
 164
 165         /* We are only interested in opcodes that create a new name */
 166
 167         if (!
 168             (walk_state->op_info->
 169              flags & (AML_NAMED | AML_CREATE | AML_FIELD))) {
 170                 return (AE_OK);
 171         }
 172
 173         /*
 174          * At this point, we know we have a Named object opcode.
 175          * Mark the method as serialized. Later code will create a mutex for
 176          * this method to enforce serialization.
 177          *
 178          * Note, ACPI_METHOD_IGNORE_SYNC_LEVEL flag means that we will ignore the
 179          * Sync Level mechanism for this method, even though it is now serialized.
 180          * Otherwise, there can be conflicts with existing ASL code that actually
 181          * uses sync levels.
 182          */
 183         walk_state->method_desc->method.sync_level = 0;
 184         walk_state->method_desc->method.info_flags |=
 185             (ACPI_METHOD_SERIALIZED | ACPI_METHOD_IGNORE_SYNC_LEVEL);
 186
 187         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 188                           "Method serialized [%4.4s] %p - [%s] (%4.4X)\n",
 189                           walk_state->method_node->name.ascii,
 190                           walk_state->method_node, walk_state->op_info->name,
 191                           walk_state->opcode));
 192
 193         /* Abort the parse, no need to examine this method any further */
 194
 195         return (AE_CTRL_TERMINATE);
 196 }
 197
 198 /*******************************************************************************
 199  *
 200  * FUNCTION:    acpi_ds_method_error
 201  *
 202  * PARAMETERS:  status          - Execution status
 203  *              walk_state      - Current state
 204  *
 205  * RETURN:      Status
 206  *
 207  * DESCRIPTION: Called on method error. Invoke the global exception handler if
 208  *              present, dump the method data if the disassembler is configured
 209  *
 210  *              Note: Allows the exception handler to change the status code
 211  *
 212  ******************************************************************************/
 213
 214 acpi_status
 215 acpi_ds_method_error(acpi_status status, struct acpi_walk_state * walk_state)
 216 {
 217         u32 aml_offset;
 218
 219         ACPI_FUNCTION_ENTRY();
 220
 221         /* Ignore AE_OK and control exception codes */
 222
 223         if (ACPI_SUCCESS(status) || (status & AE_CODE_CONTROL)) {
 224                 return (status);
 225         }
 226
 227         /* Invoke the global exception handler */
 228
 229         if (acpi_gbl_exception_handler) {
 230
 231                 /* Exit the interpreter, allow handler to execute methods */
 232
 233                 acpi_ex_exit_interpreter();
 234
 235                 /*
 236                  * Handler can map the exception code to anything it wants, including
 237                  * AE_OK, in which case the executing method will not be aborted.
 238                  */
 239                 aml_offset = (u32)ACPI_PTR_DIFF(walk_state->aml,
 240                                                 walk_state->parser_state.
 241                                                 aml_start);
 242
 243                 status = acpi_gbl_exception_handler(status,
 244                                                     walk_state->method_node ?
 245                                                     walk_state->method_node->
 246                                                     name.integer : 0,
 247                                                     walk_state->opcode,
 248                                                     aml_offset, NULL);
 249                 acpi_ex_enter_interpreter();
 250         }
 251
 252         acpi_ds_clear_implicit_return(walk_state);
 253
 254         if (ACPI_FAILURE(status)) {
 255                 acpi_ds_dump_method_stack(status, walk_state, walk_state->op);
 256
 257                 /* Display method locals/args if disassembler is present */
 258
 259 #ifdef ACPI_DISASSEMBLER
 260                 acpi_dm_dump_method_info(status, walk_state);
 261 #endif
 262         }
 263
 264         return (status);
 265 }
 266
 267 /*******************************************************************************
 268  *
 269  * FUNCTION:    acpi_ds_create_method_mutex
 270  *
 271  * PARAMETERS:  obj_desc            - The method object
 272  *
 273  * RETURN:      Status
 274  *
 275  * DESCRIPTION: Create a mutex object for a serialized control method
 276  *
 277  ******************************************************************************/
 278
 279 static acpi_status
 280 acpi_ds_create_method_mutex(union acpi_operand_object *method_desc)
 281 {
 282         union acpi_operand_object *mutex_desc;
 283         acpi_status status;
 284
 285         ACPI_FUNCTION_TRACE(ds_create_method_mutex);
 286
 287         /* Create the new mutex object */
 288
 289         mutex_desc = acpi_ut_create_internal_object(ACPI_TYPE_MUTEX);
 290         if (!mutex_desc) {
 291                 return_ACPI_STATUS(AE_NO_MEMORY);
 292         }
 293
 294         /* Create the actual OS Mutex */
 295
 296         status = acpi_os_create_mutex(&mutex_desc->mutex.os_mutex);
 297         if (ACPI_FAILURE(status)) {
 298                 acpi_ut_delete_object_desc(mutex_desc);
 299                 return_ACPI_STATUS(status);
 300         }
 301
 302         mutex_desc->mutex.sync_level = method_desc->method.sync_level;
 303         method_desc->method.mutex = mutex_desc;
 304         return_ACPI_STATUS(AE_OK);
 305 }
 306
 307 /*******************************************************************************
 308  *
 309  * FUNCTION:    acpi_ds_begin_method_execution
 310  *
 311  * PARAMETERS:  method_node         - Node of the method
 312  *              obj_desc            - The method object
 313  *              walk_state          - current state, NULL if not yet executing
 314  *                                    a method.
 315  *
 316  * RETURN:      Status
 317  *
 318  * DESCRIPTION: Prepare a method for execution. Parses the method if necessary,
 319  *              increments the thread count, and waits at the method semaphore
 320  *              for clearance to execute.
 321  *
 322  ******************************************************************************/
 323
 324 acpi_status
 325 acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
 326                                union acpi_operand_object *obj_desc,
 327                                struct acpi_walk_state *walk_state)
 328 {
 329         acpi_status status = AE_OK;
 330         char *pathname = NULL;
 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         pathname = acpi_ns_get_normalized_pathname(method_node, TRUE);
 339         if (pathname) {
 340                 ACPI_DEBUG_PRINT((ACPI_DB_TRACE_POINT,
 341                                   "Begin method [0x%p:%s] execution.\n",
 342                                   obj_desc->method.aml_start, pathname));
 343                 ACPI_FREE(pathname);
 344         } else {
 345                 ACPI_DEBUG_PRINT((ACPI_DB_TRACE_POINT,
 346                                   "Begin method [0x%p] execution.\n",
 347                                   obj_desc->method.aml_start));
 348         }
 349
 350         /* Prevent wraparound of thread count */
 351
 352         if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {
 353                 ACPI_ERROR((AE_INFO,
 354                             "Method reached maximum reentrancy limit (255)"));
 355                 return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
 356         }
 357
 358         /*
 359          * If this method is serialized, we need to acquire the method mutex.
 360          */
 361         if (obj_desc->method.info_flags & ACPI_METHOD_SERIALIZED) {
 362                 /*
 363                  * Create a mutex for the method if it is defined to be Serialized
 364                  * and a mutex has not already been created. We defer the mutex creation
 365                  * until a method is actually executed, to minimize the object count
 366                  */
 367                 if (!obj_desc->method.mutex) {
 368                         status = acpi_ds_create_method_mutex(obj_desc);
 369                         if (ACPI_FAILURE(status)) {
 370                                 return_ACPI_STATUS(status);
 371                         }
 372                 }
 373
 374                 /*
 375                  * The current_sync_level (per-thread) must be less than or equal to
 376                  * the sync level of the method. This mechanism provides some
 377                  * deadlock prevention.
 378                  *
 379                  * If the method was auto-serialized, we just ignore the sync level
 380                  * mechanism, because auto-serialization of methods can interfere
 381                  * with ASL code that actually uses sync levels.
 382                  *
 383                  * Top-level method invocation has no walk state at this point
 384                  */
 385                 if (walk_state &&
 386                     (!(obj_desc->method.
 387                        info_flags & ACPI_METHOD_IGNORE_SYNC_LEVEL))
 388                     && (walk_state->thread->current_sync_level >
 389                         obj_desc->method.mutex->mutex.sync_level)) {
 390                         ACPI_ERROR((AE_INFO,
 391                                     "Cannot acquire Mutex for method [%4.4s], current SyncLevel is too large (%u)",
 392                                     acpi_ut_get_node_name(method_node),
 393                                     walk_state->thread->current_sync_level));
 394
 395                         return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
 396                 }
 397
 398                 /*
 399                  * Obtain the method mutex if necessary. Do not acquire mutex for a
 400                  * recursive call.
 401                  */
 402                 if (!walk_state ||
 403                     !obj_desc->method.mutex->mutex.thread_id ||
 404                     (walk_state->thread->thread_id !=
 405                      obj_desc->method.mutex->mutex.thread_id)) {
 406                         /*
 407                          * Acquire the method mutex. This releases the interpreter if we
 408                          * block (and reacquires it before it returns)
 409                          */
 410                         status =
 411                             acpi_ex_system_wait_mutex(obj_desc->method.mutex->
 412                                                       mutex.os_mutex,
 413                                                       ACPI_WAIT_FOREVER);
 414                         if (ACPI_FAILURE(status)) {
 415                                 return_ACPI_STATUS(status);
 416                         }
 417
 418                         /* Update the mutex and walk info and save the original sync_level */
 419
 420                         if (walk_state) {
 421                                 obj_desc->method.mutex->mutex.
 422                                     original_sync_level =
 423                                     walk_state->thread->current_sync_level;
 424
 425                                 obj_desc->method.mutex->mutex.thread_id =
 426                                     walk_state->thread->thread_id;
 427                                 walk_state->thread->current_sync_level =
 428                                     obj_desc->method.sync_level;
 429                         } else {
 430                                 obj_desc->method.mutex->mutex.
 431                                     original_sync_level =
 432                                     obj_desc->method.mutex->mutex.sync_level;
 433                         }
 434                 }
 435
 436                 /* Always increase acquisition depth */
 437
 438                 obj_desc->method.mutex->mutex.acquisition_depth++;
 439         }
 440
 441         /*
 442          * Allocate an Owner ID for this method, only if this is the first thread
 443          * to begin concurrent execution. We only need one owner_id, even if the
 444          * method is invoked recursively.
 445          */
 446         if (!obj_desc->method.owner_id) {
 447                 status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
 448                 if (ACPI_FAILURE(status)) {
 449                         goto cleanup;
 450                 }
 451         }
 452
 453         /*
 454          * Increment the method parse tree thread count since it has been
 455          * reentered one more time (even if it is the same thread)
 456          */
 457         obj_desc->method.thread_count++;
 458         acpi_method_count++;
 459         return_ACPI_STATUS(status);
 460
 461 cleanup:
 462         /* On error, must release the method mutex (if present) */
 463
 464         if (obj_desc->method.mutex) {
 465                 acpi_os_release_mutex(obj_desc->method.mutex->mutex.os_mutex);
 466         }
 467         return_ACPI_STATUS(status);
 468 }
 469
 470 /*******************************************************************************
 471  *
 472  * FUNCTION:    acpi_ds_call_control_method
 473  *
 474  * PARAMETERS:  thread              - Info for this thread
 475  *              this_walk_state     - Current walk state
 476  *              op                  - Current Op to be walked
 477  *
 478  * RETURN:      Status
 479  *
 480  * DESCRIPTION: Transfer execution to a called control method
 481  *
 482  ******************************************************************************/
 483
 484 acpi_status
 485 acpi_ds_call_control_method(struct acpi_thread_state *thread,
 486                             struct acpi_walk_state *this_walk_state,
 487                             union acpi_parse_object *op)
 488 {
 489         acpi_status status;
 490         struct acpi_namespace_node *method_node;
 491         struct acpi_walk_state *next_walk_state = NULL;
 492         union acpi_operand_object *obj_desc;
 493         struct acpi_evaluate_info *info;
 494         u32 i;
 495
 496         ACPI_FUNCTION_TRACE_PTR(ds_call_control_method, this_walk_state);
 497
 498         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 499                           "Calling method %p, currentstate=%p\n",
 500                           this_walk_state->prev_op, this_walk_state));
 501
 502         /*
 503          * Get the namespace entry for the control method we are about to call
 504          */
 505         method_node = this_walk_state->method_call_node;
 506         if (!method_node) {
 507                 return_ACPI_STATUS(AE_NULL_ENTRY);
 508         }
 509
 510         obj_desc = acpi_ns_get_attached_object(method_node);
 511         if (!obj_desc) {
 512                 return_ACPI_STATUS(AE_NULL_OBJECT);
 513         }
 514
 515         /* Init for new method, possibly wait on method mutex */
 516
 517         status = acpi_ds_begin_method_execution(method_node, obj_desc,
 518                                                 this_walk_state);
 519         if (ACPI_FAILURE(status)) {
 520                 return_ACPI_STATUS(status);
 521         }
 522
 523         /* Begin method parse/execution. Create a new walk state */
 524
 525         next_walk_state = acpi_ds_create_walk_state(obj_desc->method.owner_id,
 526                                                     NULL, obj_desc, thread);
 527         if (!next_walk_state) {
 528                 status = AE_NO_MEMORY;
 529                 goto cleanup;
 530         }
 531
 532         /*
 533          * The resolved arguments were put on the previous walk state's operand
 534          * stack. Operands on the previous walk state stack always
 535          * start at index 0. Also, null terminate the list of arguments
 536          */
 537         this_walk_state->operands[this_walk_state->num_operands] = NULL;
 538
 539         /*
 540          * Allocate and initialize the evaluation information block
 541          * TBD: this is somewhat inefficient, should change interface to
 542          * ds_init_aml_walk. For now, keeps this struct off the CPU stack
 543          */
 544         info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
 545         if (!info) {
 546                 status = AE_NO_MEMORY;
 547                 goto cleanup;
 548         }
 549
 550         info->parameters = &this_walk_state->operands[0];
 551
 552         status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
 553                                        obj_desc->method.aml_start,
 554                                        obj_desc->method.aml_length, info,
 555                                        ACPI_IMODE_EXECUTE);
 556
 557         ACPI_FREE(info);
 558         if (ACPI_FAILURE(status)) {
 559                 goto cleanup;
 560         }
 561
 562         /*
 563          * Delete the operands on the previous walkstate operand stack
 564          * (they were copied to new objects)
 565          */
 566         for (i = 0; i < obj_desc->method.param_count; i++) {
 567                 acpi_ut_remove_reference(this_walk_state->operands[i]);
 568                 this_walk_state->operands[i] = NULL;
 569         }
 570
 571         /* Clear the operand stack */
 572
 573         this_walk_state->num_operands = 0;
 574
 575         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 576                           "**** Begin nested execution of [%4.4s] **** WalkState=%p\n",
 577                           method_node->name.ascii, next_walk_state));
 578
 579         /* Invoke an internal method if necessary */
 580
 581         if (obj_desc->method.info_flags & ACPI_METHOD_INTERNAL_ONLY) {
 582                 status =
 583                     obj_desc->method.dispatch.implementation(next_walk_state);
 584                 if (status == AE_OK) {
 585                         status = AE_CTRL_TERMINATE;
 586                 }
 587         }
 588
 589         return_ACPI_STATUS(status);
 590
 591 cleanup:
 592
 593         /* On error, we must terminate the method properly */
 594
 595         acpi_ds_terminate_control_method(obj_desc, next_walk_state);
 596         if (next_walk_state) {
 597                 acpi_ds_delete_walk_state(next_walk_state);
 598         }
 599
 600         return_ACPI_STATUS(status);
 601 }
 602
 603 /*******************************************************************************
 604  *
 605  * FUNCTION:    acpi_ds_restart_control_method
 606  *
 607  * PARAMETERS:  walk_state          - State for preempted method (caller)
 608  *              return_desc         - Return value from the called method
 609  *
 610  * RETURN:      Status
 611  *
 612  * DESCRIPTION: Restart a method that was preempted by another (nested) method
 613  *              invocation. Handle the return value (if any) from the callee.
 614  *
 615  ******************************************************************************/
 616
 617 acpi_status
 618 acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
 619                                union acpi_operand_object *return_desc)
 620 {
 621         acpi_status status;
 622         int same_as_implicit_return;
 623
 624         ACPI_FUNCTION_TRACE_PTR(ds_restart_control_method, walk_state);
 625
 626         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 627                           "****Restart [%4.4s] Op %p ReturnValueFromCallee %p\n",
 628                           acpi_ut_get_node_name(walk_state->method_node),
 629                           walk_state->method_call_op, return_desc));
 630
 631         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 632                           "    ReturnFromThisMethodUsed?=%X ResStack %p Walk %p\n",
 633                           walk_state->return_used,
 634                           walk_state->results, walk_state));
 635
 636         /* Did the called method return a value? */
 637
 638         if (return_desc) {
 639
 640                 /* Is the implicit return object the same as the return desc? */
 641
 642                 same_as_implicit_return =
 643                     (walk_state->implicit_return_obj == return_desc);
 644
 645                 /* Are we actually going to use the return value? */
 646
 647                 if (walk_state->return_used) {
 648
 649                         /* Save the return value from the previous method */
 650
 651                         status = acpi_ds_result_push(return_desc, walk_state);
 652                         if (ACPI_FAILURE(status)) {
 653                                 acpi_ut_remove_reference(return_desc);
 654                                 return_ACPI_STATUS(status);
 655                         }
 656
 657                         /*
 658                          * Save as THIS method's return value in case it is returned
 659                          * immediately to yet another method
 660                          */
 661                         walk_state->return_desc = return_desc;
 662                 }
 663
 664                 /*
 665                  * The following code is the optional support for the so-called
 666                  * "implicit return". Some AML code assumes that the last value of the
 667                  * method is "implicitly" returned to the caller, in the absence of an
 668                  * explicit return value.
 669                  *
 670                  * Just save the last result of the method as the return value.
 671                  *
 672                  * NOTE: this is optional because the ASL language does not actually
 673                  * support this behavior.
 674                  */
 675                 else if (!acpi_ds_do_implicit_return
 676                          (return_desc, walk_state, FALSE)
 677                          || same_as_implicit_return) {
 678                         /*
 679                          * Delete the return value if it will not be used by the
 680                          * calling method or remove one reference if the explicit return
 681                          * is the same as the implicit return value.
 682                          */
 683                         acpi_ut_remove_reference(return_desc);
 684                 }
 685         }
 686
 687         return_ACPI_STATUS(AE_OK);
 688 }
 689
 690 /*******************************************************************************
 691  *
 692  * FUNCTION:    acpi_ds_terminate_control_method
 693  *
 694  * PARAMETERS:  method_desc         - Method object
 695  *              walk_state          - State associated with the method
 696  *
 697  * RETURN:      None
 698  *
 699  * DESCRIPTION: Terminate a control method. Delete everything that the method
 700  *              created, delete all locals and arguments, and delete the parse
 701  *              tree if requested.
 702  *
 703  * MUTEX:       Interpreter is locked
 704  *
 705  ******************************************************************************/
 706
 707 void
 708 acpi_ds_terminate_control_method(union acpi_operand_object *method_desc,
 709                                  struct acpi_walk_state *walk_state)
 710 {
 711         char *pathname = NULL;
 712
 713         ACPI_FUNCTION_TRACE_PTR(ds_terminate_control_method, walk_state);
 714
 715         /* method_desc is required, walk_state is optional */
 716
 717         if (!method_desc) {
 718                 return_VOID;
 719         }
 720
 721         if (walk_state) {
 722
 723                 /* Delete all arguments and locals */
 724
 725                 acpi_ds_method_data_delete_all(walk_state);
 726
 727                 /*
 728                  * If method is serialized, release the mutex and restore the
 729                  * current sync level for this thread
 730                  */
 731                 if (method_desc->method.mutex) {
 732
 733                         /* Acquisition Depth handles recursive calls */
 734
 735                         method_desc->method.mutex->mutex.acquisition_depth--;
 736                         if (!method_desc->method.mutex->mutex.acquisition_depth) {
 737                                 walk_state->thread->current_sync_level =
 738                                     method_desc->method.mutex->mutex.
 739                                     original_sync_level;
 740
 741                                 acpi_os_release_mutex(method_desc->method.
 742                                                       mutex->mutex.os_mutex);
 743                                 method_desc->method.mutex->mutex.thread_id = 0;
 744                         }
 745                 }
 746
 747                 /*
 748                  * Delete any namespace objects created anywhere within the
 749                  * namespace by the execution of this method. Unless:
 750                  * 1) This method is a module-level executable code method, in which
 751                  *    case we want make the objects permanent.
 752                  * 2) There are other threads executing the method, in which case we
 753                  *    will wait until the last thread has completed.
 754                  */
 755                 if (!(method_desc->method.info_flags & ACPI_METHOD_MODULE_LEVEL)
 756                     && (method_desc->method.thread_count == 1)) {
 757
 758                         /* Delete any direct children of (created by) this method */
 759
 760                         acpi_ns_delete_namespace_subtree(walk_state->
 761                                                          method_node);
 762
 763                         /*
 764                          * Delete any objects that were created by this method
 765                          * elsewhere in the namespace (if any were created).
 766                          * Use of the ACPI_METHOD_MODIFIED_NAMESPACE optimizes the
 767                          * deletion such that we don't have to perform an entire
 768                          * namespace walk for every control method execution.
 769                          */
 770                         if (method_desc->method.
 771                             info_flags & ACPI_METHOD_MODIFIED_NAMESPACE) {
 772                                 acpi_ns_delete_namespace_by_owner(method_desc->
 773                                                                   method.
 774                                                                   owner_id);
 775                                 method_desc->method.info_flags &=
 776                                     ~ACPI_METHOD_MODIFIED_NAMESPACE;
 777                         }
 778                 }
 779         }
 780
 781         /* Decrement the thread count on the method */
 782
 783         if (method_desc->method.thread_count) {
 784                 method_desc->method.thread_count--;
 785         } else {
 786                 ACPI_ERROR((AE_INFO, "Invalid zero thread count in method"));
 787         }
 788
 789         /* Are there any other threads currently executing this method? */
 790
 791         if (method_desc->method.thread_count) {
 792                 /*
 793                  * Additional threads. Do not release the owner_id in this case,
 794                  * we immediately reuse it for the next thread executing this method
 795                  */
 796                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 797                                   "*** Completed execution of one thread, %u threads remaining\n",
 798                                   method_desc->method.thread_count));
 799         } else {
 800                 /* This is the only executing thread for this method */
 801
 802                 /*
 803                  * Support to dynamically change a method from not_serialized to
 804                  * Serialized if it appears that the method is incorrectly written and
 805                  * does not support multiple thread execution. The best example of this
 806                  * is if such a method creates namespace objects and blocks. A second
 807                  * thread will fail with an AE_ALREADY_EXISTS exception.
 808                  *
 809                  * This code is here because we must wait until the last thread exits
 810                  * before marking the method as serialized.
 811                  */
 812                 if (method_desc->method.
 813                     info_flags & ACPI_METHOD_SERIALIZED_PENDING) {
 814                         if (walk_state) {
 815                                 ACPI_INFO((AE_INFO,
 816                                            "Marking method %4.4s as Serialized because of AE_ALREADY_EXISTS error",
 817                                            walk_state->method_node->name.
 818                                            ascii));
 819                         }
 820
 821                         /*
 822                          * Method tried to create an object twice and was marked as
 823                          * "pending serialized". The probable cause is that the method
 824                          * cannot handle reentrancy.
 825                          *
 826                          * The method was created as not_serialized, but it tried to create
 827                          * a named object and then blocked, causing the second thread
 828                          * entrance to begin and then fail. Workaround this problem by
 829                          * marking the method permanently as Serialized when the last
 830                          * thread exits here.
 831                          */
 832                         method_desc->method.info_flags &=
 833                             ~ACPI_METHOD_SERIALIZED_PENDING;
 834                         method_desc->method.info_flags |=
 835                             (ACPI_METHOD_SERIALIZED |
 836                              ACPI_METHOD_IGNORE_SYNC_LEVEL);
 837                         method_desc->method.sync_level = 0;
 838                 }
 839
 840                 /* No more threads, we can free the owner_id */
 841
 842                 if (!
 843                     (method_desc->method.
 844                      info_flags & ACPI_METHOD_MODULE_LEVEL)) {
 845                         acpi_ut_release_owner_id(&method_desc->method.owner_id);
 846                 }
 847         }
 848
 849         if (method_desc->method.node) {
 850                 pathname = acpi_ns_get_normalized_pathname((struct
 851                                                             acpi_namespace_node
 852                                                             *)method_desc->
 853                                                            method.node, TRUE);
 854         }
 855         if (pathname) {
 856                 ACPI_DEBUG_PRINT((ACPI_DB_TRACE_POINT,
 857                                   "End method [0x%p:%s] execution.\n",
 858                                   method_desc->method.aml_start, pathname));
 859                 ACPI_FREE(pathname);
 860         } else {
 861                 ACPI_DEBUG_PRINT((ACPI_DB_TRACE_POINT,
 862                                   "End method [0x%p] execution.\n",
 863                                   method_desc->method.aml_start));
 864         }
 865
 866         return_VOID;
 867 }