drivers/acpi/acpica/dsutils.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: dsutils - Dispatcher utilities
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2013, 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 "acparser.h"
  47 #include "amlcode.h"
  48 #include "acdispat.h"
  49 #include "acinterp.h"
  50 #include "acnamesp.h"
  51 #include "acdebug.h"
  52
  53 #define _COMPONENT          ACPI_DISPATCHER
  54 ACPI_MODULE_NAME("dsutils")
  55
  56 /*******************************************************************************
  57  *
  58  * FUNCTION:    acpi_ds_clear_implicit_return
  59  *
  60  * PARAMETERS:  walk_state          - Current State
  61  *
  62  * RETURN:      None.
  63  *
  64  * DESCRIPTION: Clear and remove a reference on an implicit return value. Used
  65  *              to delete "stale" return values (if enabled, the return value
  66  *              from every operator is saved at least momentarily, in case the
  67  *              parent method exits.)
  68  *
  69  ******************************************************************************/
  70 void acpi_ds_clear_implicit_return(struct acpi_walk_state *walk_state)
  71 {
  72         ACPI_FUNCTION_NAME(ds_clear_implicit_return);
  73
  74         /*
  75          * Slack must be enabled for this feature
  76          */
  77         if (!acpi_gbl_enable_interpreter_slack) {
  78                 return;
  79         }
  80
  81         if (walk_state->implicit_return_obj) {
  82                 /*
  83                  * Delete any "stale" implicit return. However, in
  84                  * complex statements, the implicit return value can be
  85                  * bubbled up several levels.
  86                  */
  87                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
  88                                   "Removing reference on stale implicit return obj %p\n",
  89                                   walk_state->implicit_return_obj));
  90
  91                 acpi_ut_remove_reference(walk_state->implicit_return_obj);
  92                 walk_state->implicit_return_obj = NULL;
  93         }
  94 }
  95
  96 #ifndef ACPI_NO_METHOD_EXECUTION
  97 /*******************************************************************************
  98  *
  99  * FUNCTION:    acpi_ds_do_implicit_return
 100  *
 101  * PARAMETERS:  return_desc         - The return value
 102  *              walk_state          - Current State
 103  *              add_reference       - True if a reference should be added to the
 104  *                                    return object
 105  *
 106  * RETURN:      TRUE if implicit return enabled, FALSE otherwise
 107  *
 108  * DESCRIPTION: Implements the optional "implicit return".  We save the result
 109  *              of every ASL operator and control method invocation in case the
 110  *              parent method exit. Before storing a new return value, we
 111  *              delete the previous return value.
 112  *
 113  ******************************************************************************/
 114
 115 u8
 116 acpi_ds_do_implicit_return(union acpi_operand_object *return_desc,
 117                            struct acpi_walk_state *walk_state, u8 add_reference)
 118 {
 119         ACPI_FUNCTION_NAME(ds_do_implicit_return);
 120
 121         /*
 122          * Slack must be enabled for this feature, and we must
 123          * have a valid return object
 124          */
 125         if ((!acpi_gbl_enable_interpreter_slack) || (!return_desc)) {
 126                 return (FALSE);
 127         }
 128
 129         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 130                           "Result %p will be implicitly returned; Prev=%p\n",
 131                           return_desc, walk_state->implicit_return_obj));
 132
 133         /*
 134          * Delete any "stale" implicit return value first. However, in
 135          * complex statements, the implicit return value can be
 136          * bubbled up several levels, so we don't clear the value if it
 137          * is the same as the return_desc.
 138          */
 139         if (walk_state->implicit_return_obj) {
 140                 if (walk_state->implicit_return_obj == return_desc) {
 141                         return (TRUE);
 142                 }
 143                 acpi_ds_clear_implicit_return(walk_state);
 144         }
 145
 146         /* Save the implicit return value, add a reference if requested */
 147
 148         walk_state->implicit_return_obj = return_desc;
 149         if (add_reference) {
 150                 acpi_ut_add_reference(return_desc);
 151         }
 152
 153         return (TRUE);
 154 }
 155
 156 /*******************************************************************************
 157  *
 158  * FUNCTION:    acpi_ds_is_result_used
 159  *
 160  * PARAMETERS:  op                  - Current Op
 161  *              walk_state          - Current State
 162  *
 163  * RETURN:      TRUE if result is used, FALSE otherwise
 164  *
 165  * DESCRIPTION: Check if a result object will be used by the parent
 166  *
 167  ******************************************************************************/
 168
 169 u8
 170 acpi_ds_is_result_used(union acpi_parse_object * op,
 171                        struct acpi_walk_state * walk_state)
 172 {
 173         const struct acpi_opcode_info *parent_info;
 174
 175         ACPI_FUNCTION_TRACE_PTR(ds_is_result_used, op);
 176
 177         /* Must have both an Op and a Result Object */
 178
 179         if (!op) {
 180                 ACPI_ERROR((AE_INFO, "Null Op"));
 181                 return_UINT8(TRUE);
 182         }
 183
 184         /*
 185          * We know that this operator is not a
 186          * Return() operator (would not come here.) The following code is the
 187          * optional support for a so-called "implicit return". Some AML code
 188          * assumes that the last value of the method is "implicitly" returned
 189          * to the caller. Just save the last result as the return value.
 190          * NOTE: this is optional because the ASL language does not actually
 191          * support this behavior.
 192          */
 193         (void)acpi_ds_do_implicit_return(walk_state->result_obj, walk_state,
 194                                          TRUE);
 195
 196         /*
 197          * Now determine if the parent will use the result
 198          *
 199          * If there is no parent, or the parent is a scope_op, we are executing
 200          * at the method level. An executing method typically has no parent,
 201          * since each method is parsed separately. A method invoked externally
 202          * via execute_control_method has a scope_op as the parent.
 203          */
 204         if ((!op->common.parent) ||
 205             (op->common.parent->common.aml_opcode == AML_SCOPE_OP)) {
 206
 207                 /* No parent, the return value cannot possibly be used */
 208
 209                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 210                                   "At Method level, result of [%s] not used\n",
 211                                   acpi_ps_get_opcode_name(op->common.
 212                                                           aml_opcode)));
 213                 return_UINT8(FALSE);
 214         }
 215
 216         /* Get info on the parent. The root_op is AML_SCOPE */
 217
 218         parent_info =
 219             acpi_ps_get_opcode_info(op->common.parent->common.aml_opcode);
 220         if (parent_info->class == AML_CLASS_UNKNOWN) {
 221                 ACPI_ERROR((AE_INFO, "Unknown parent opcode Op=%p", op));
 222                 return_UINT8(FALSE);
 223         }
 224
 225         /*
 226          * Decide what to do with the result based on the parent. If
 227          * the parent opcode will not use the result, delete the object.
 228          * Otherwise leave it as is, it will be deleted when it is used
 229          * as an operand later.
 230          */
 231         switch (parent_info->class) {
 232         case AML_CLASS_CONTROL:
 233
 234                 switch (op->common.parent->common.aml_opcode) {
 235                 case AML_RETURN_OP:
 236
 237                         /* Never delete the return value associated with a return opcode */
 238
 239                         goto result_used;
 240
 241                 case AML_IF_OP:
 242                 case AML_WHILE_OP:
 243                         /*
 244                          * If we are executing the predicate AND this is the predicate op,
 245                          * we will use the return value
 246                          */
 247                         if ((walk_state->control_state->common.state ==
 248                              ACPI_CONTROL_PREDICATE_EXECUTING)
 249                             && (walk_state->control_state->control.
 250                                 predicate_op == op)) {
 251                                 goto result_used;
 252                         }
 253                         break;
 254
 255                 default:
 256
 257                         /* Ignore other control opcodes */
 258
 259                         break;
 260                 }
 261
 262                 /* The general control opcode returns no result */
 263
 264                 goto result_not_used;
 265
 266         case AML_CLASS_CREATE:
 267                 /*
 268                  * These opcodes allow term_arg(s) as operands and therefore
 269                  * the operands can be method calls. The result is used.
 270                  */
 271                 goto result_used;
 272
 273         case AML_CLASS_NAMED_OBJECT:
 274
 275                 if ((op->common.parent->common.aml_opcode == AML_REGION_OP) ||
 276                     (op->common.parent->common.aml_opcode == AML_DATA_REGION_OP)
 277                     || (op->common.parent->common.aml_opcode == AML_PACKAGE_OP)
 278                     || (op->common.parent->common.aml_opcode ==
 279                         AML_VAR_PACKAGE_OP)
 280                     || (op->common.parent->common.aml_opcode == AML_BUFFER_OP)
 281                     || (op->common.parent->common.aml_opcode ==
 282                         AML_INT_EVAL_SUBTREE_OP)
 283                     || (op->common.parent->common.aml_opcode ==
 284                         AML_BANK_FIELD_OP)) {
 285                         /*
 286                          * These opcodes allow term_arg(s) as operands and therefore
 287                          * the operands can be method calls. The result is used.
 288                          */
 289                         goto result_used;
 290                 }
 291
 292                 goto result_not_used;
 293
 294         default:
 295                 /*
 296                  * In all other cases. the parent will actually use the return
 297                  * object, so keep it.
 298                  */
 299                 goto result_used;
 300         }
 301
 302 result_used:
 303         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 304                           "Result of [%s] used by Parent [%s] Op=%p\n",
 305                           acpi_ps_get_opcode_name(op->common.aml_opcode),
 306                           acpi_ps_get_opcode_name(op->common.parent->common.
 307                                                   aml_opcode), op));
 308
 309         return_UINT8(TRUE);
 310
 311 result_not_used:
 312         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 313                           "Result of [%s] not used by Parent [%s] Op=%p\n",
 314                           acpi_ps_get_opcode_name(op->common.aml_opcode),
 315                           acpi_ps_get_opcode_name(op->common.parent->common.
 316                                                   aml_opcode), op));
 317
 318         return_UINT8(FALSE);
 319 }
 320
 321 /*******************************************************************************
 322  *
 323  * FUNCTION:    acpi_ds_delete_result_if_not_used
 324  *
 325  * PARAMETERS:  op              - Current parse Op
 326  *              result_obj      - Result of the operation
 327  *              walk_state      - Current state
 328  *
 329  * RETURN:      Status
 330  *
 331  * DESCRIPTION: Used after interpretation of an opcode. If there is an internal
 332  *              result descriptor, check if the parent opcode will actually use
 333  *              this result. If not, delete the result now so that it will
 334  *              not become orphaned.
 335  *
 336  ******************************************************************************/
 337
 338 void
 339 acpi_ds_delete_result_if_not_used(union acpi_parse_object *op,
 340                                   union acpi_operand_object *result_obj,
 341                                   struct acpi_walk_state *walk_state)
 342 {
 343         union acpi_operand_object *obj_desc;
 344         acpi_status status;
 345
 346         ACPI_FUNCTION_TRACE_PTR(ds_delete_result_if_not_used, result_obj);
 347
 348         if (!op) {
 349                 ACPI_ERROR((AE_INFO, "Null Op"));
 350                 return_VOID;
 351         }
 352
 353         if (!result_obj) {
 354                 return_VOID;
 355         }
 356
 357         if (!acpi_ds_is_result_used(op, walk_state)) {
 358
 359                 /* Must pop the result stack (obj_desc should be equal to result_obj) */
 360
 361                 status = acpi_ds_result_pop(&obj_desc, walk_state);
 362                 if (ACPI_SUCCESS(status)) {
 363                         acpi_ut_remove_reference(result_obj);
 364                 }
 365         }
 366
 367         return_VOID;
 368 }
 369
 370 /*******************************************************************************
 371  *
 372  * FUNCTION:    acpi_ds_resolve_operands
 373  *
 374  * PARAMETERS:  walk_state          - Current walk state with operands on stack
 375  *
 376  * RETURN:      Status
 377  *
 378  * DESCRIPTION: Resolve all operands to their values. Used to prepare
 379  *              arguments to a control method invocation (a call from one
 380  *              method to another.)
 381  *
 382  ******************************************************************************/
 383
 384 acpi_status acpi_ds_resolve_operands(struct acpi_walk_state *walk_state)
 385 {
 386         u32 i;
 387         acpi_status status = AE_OK;
 388
 389         ACPI_FUNCTION_TRACE_PTR(ds_resolve_operands, walk_state);
 390
 391         /*
 392          * Attempt to resolve each of the valid operands
 393          * Method arguments are passed by reference, not by value. This means
 394          * that the actual objects are passed, not copies of the objects.
 395          */
 396         for (i = 0; i < walk_state->num_operands; i++) {
 397                 status =
 398                     acpi_ex_resolve_to_value(&walk_state->operands[i],
 399                                              walk_state);
 400                 if (ACPI_FAILURE(status)) {
 401                         break;
 402                 }
 403         }
 404
 405         return_ACPI_STATUS(status);
 406 }
 407
 408 /*******************************************************************************
 409  *
 410  * FUNCTION:    acpi_ds_clear_operands
 411  *
 412  * PARAMETERS:  walk_state          - Current walk state with operands on stack
 413  *
 414  * RETURN:      None
 415  *
 416  * DESCRIPTION: Clear all operands on the current walk state operand stack.
 417  *
 418  ******************************************************************************/
 419
 420 void acpi_ds_clear_operands(struct acpi_walk_state *walk_state)
 421 {
 422         u32 i;
 423
 424         ACPI_FUNCTION_TRACE_PTR(ds_clear_operands, walk_state);
 425
 426         /* Remove a reference on each operand on the stack */
 427
 428         for (i = 0; i < walk_state->num_operands; i++) {
 429                 /*
 430                  * Remove a reference to all operands, including both
 431                  * "Arguments" and "Targets".
 432                  */
 433                 acpi_ut_remove_reference(walk_state->operands[i]);
 434                 walk_state->operands[i] = NULL;
 435         }
 436
 437         walk_state->num_operands = 0;
 438         return_VOID;
 439 }
 440 #endif
 441
 442 /*******************************************************************************
 443  *
 444  * FUNCTION:    acpi_ds_create_operand
 445  *
 446  * PARAMETERS:  walk_state      - Current walk state
 447  *              arg             - Parse object for the argument
 448  *              arg_index       - Which argument (zero based)
 449  *
 450  * RETURN:      Status
 451  *
 452  * DESCRIPTION: Translate a parse tree object that is an argument to an AML
 453  *              opcode to the equivalent interpreter object. This may include
 454  *              looking up a name or entering a new name into the internal
 455  *              namespace.
 456  *
 457  ******************************************************************************/
 458
 459 acpi_status
 460 acpi_ds_create_operand(struct acpi_walk_state *walk_state,
 461                        union acpi_parse_object *arg, u32 arg_index)
 462 {
 463         acpi_status status = AE_OK;
 464         char *name_string;
 465         u32 name_length;
 466         union acpi_operand_object *obj_desc;
 467         union acpi_parse_object *parent_op;
 468         u16 opcode;
 469         acpi_interpreter_mode interpreter_mode;
 470         const struct acpi_opcode_info *op_info;
 471
 472         ACPI_FUNCTION_TRACE_PTR(ds_create_operand, arg);
 473
 474         /* A valid name must be looked up in the namespace */
 475
 476         if ((arg->common.aml_opcode == AML_INT_NAMEPATH_OP) &&
 477             (arg->common.value.string) &&
 478             !(arg->common.flags & ACPI_PARSEOP_IN_STACK)) {
 479                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Getting a name: Arg=%p\n",
 480                                   arg));
 481
 482                 /* Get the entire name string from the AML stream */
 483
 484                 status =
 485                     acpi_ex_get_name_string(ACPI_TYPE_ANY,
 486                                             arg->common.value.buffer,
 487                                             &name_string, &name_length);
 488
 489                 if (ACPI_FAILURE(status)) {
 490                         return_ACPI_STATUS(status);
 491                 }
 492
 493                 /* All prefixes have been handled, and the name is in name_string */
 494
 495                 /*
 496                  * Special handling for buffer_field declarations. This is a deferred
 497                  * opcode that unfortunately defines the field name as the last
 498                  * parameter instead of the first. We get here when we are performing
 499                  * the deferred execution, so the actual name of the field is already
 500                  * in the namespace. We don't want to attempt to look it up again
 501                  * because we may be executing in a different scope than where the
 502                  * actual opcode exists.
 503                  */
 504                 if ((walk_state->deferred_node) &&
 505                     (walk_state->deferred_node->type == ACPI_TYPE_BUFFER_FIELD)
 506                     && (arg_index ==
 507                         (u32) ((walk_state->opcode ==
 508                                 AML_CREATE_FIELD_OP) ? 3 : 2))) {
 509                         obj_desc =
 510                             ACPI_CAST_PTR(union acpi_operand_object,
 511                                           walk_state->deferred_node);
 512                         status = AE_OK;
 513                 } else {        /* All other opcodes */
 514
 515                         /*
 516                          * Differentiate between a namespace "create" operation
 517                          * versus a "lookup" operation (IMODE_LOAD_PASS2 vs.
 518                          * IMODE_EXECUTE) in order to support the creation of
 519                          * namespace objects during the execution of control methods.
 520                          */
 521                         parent_op = arg->common.parent;
 522                         op_info =
 523                             acpi_ps_get_opcode_info(parent_op->common.
 524                                                     aml_opcode);
 525                         if ((op_info->flags & AML_NSNODE)
 526                             && (parent_op->common.aml_opcode !=
 527                                 AML_INT_METHODCALL_OP)
 528                             && (parent_op->common.aml_opcode != AML_REGION_OP)
 529                             && (parent_op->common.aml_opcode !=
 530                                 AML_INT_NAMEPATH_OP)) {
 531
 532                                 /* Enter name into namespace if not found */
 533
 534                                 interpreter_mode = ACPI_IMODE_LOAD_PASS2;
 535                         } else {
 536                                 /* Return a failure if name not found */
 537
 538                                 interpreter_mode = ACPI_IMODE_EXECUTE;
 539                         }
 540
 541                         status =
 542                             acpi_ns_lookup(walk_state->scope_info, name_string,
 543                                            ACPI_TYPE_ANY, interpreter_mode,
 544                                            ACPI_NS_SEARCH_PARENT |
 545                                            ACPI_NS_DONT_OPEN_SCOPE, walk_state,
 546                                            ACPI_CAST_INDIRECT_PTR(struct
 547                                                                   acpi_namespace_node,
 548                                                                   &obj_desc));
 549                         /*
 550                          * The only case where we pass through (ignore) a NOT_FOUND
 551                          * error is for the cond_ref_of opcode.
 552                          */
 553                         if (status == AE_NOT_FOUND) {
 554                                 if (parent_op->common.aml_opcode ==
 555                                     AML_COND_REF_OF_OP) {
 556                                         /*
 557                                          * For the Conditional Reference op, it's OK if
 558                                          * the name is not found;  We just need a way to
 559                                          * indicate this to the interpreter, set the
 560                                          * object to the root
 561                                          */
 562                                         obj_desc =
 563                                             ACPI_CAST_PTR(union
 564                                                                  acpi_operand_object,
 565                                                                  acpi_gbl_root_node);
 566                                         status = AE_OK;
 567                                 } else {
 568                                         /*
 569                                          * We just plain didn't find it -- which is a
 570                                          * very serious error at this point
 571                                          */
 572                                         status = AE_AML_NAME_NOT_FOUND;
 573                                 }
 574                         }
 575
 576                         if (ACPI_FAILURE(status)) {
 577                                 ACPI_ERROR_NAMESPACE(name_string, status);
 578                         }
 579                 }
 580
 581                 /* Free the namestring created above */
 582
 583                 ACPI_FREE(name_string);
 584
 585                 /* Check status from the lookup */
 586
 587                 if (ACPI_FAILURE(status)) {
 588                         return_ACPI_STATUS(status);
 589                 }
 590
 591                 /* Put the resulting object onto the current object stack */
 592
 593                 status = acpi_ds_obj_stack_push(obj_desc, walk_state);
 594                 if (ACPI_FAILURE(status)) {
 595                         return_ACPI_STATUS(status);
 596                 }
 597                 ACPI_DEBUGGER_EXEC(acpi_db_display_argument_object
 598                                    (obj_desc, walk_state));
 599         } else {
 600                 /* Check for null name case */
 601
 602                 if ((arg->common.aml_opcode == AML_INT_NAMEPATH_OP) &&
 603                     !(arg->common.flags & ACPI_PARSEOP_IN_STACK)) {
 604                         /*
 605                          * If the name is null, this means that this is an
 606                          * optional result parameter that was not specified
 607                          * in the original ASL. Create a Zero Constant for a
 608                          * placeholder. (Store to a constant is a Noop.)
 609                          */
 610                         opcode = AML_ZERO_OP;   /* Has no arguments! */
 611
 612                         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 613                                           "Null namepath: Arg=%p\n", arg));
 614                 } else {
 615                         opcode = arg->common.aml_opcode;
 616                 }
 617
 618                 /* Get the object type of the argument */
 619
 620                 op_info = acpi_ps_get_opcode_info(opcode);
 621                 if (op_info->object_type == ACPI_TYPE_INVALID) {
 622                         return_ACPI_STATUS(AE_NOT_IMPLEMENTED);
 623                 }
 624
 625                 if ((op_info->flags & AML_HAS_RETVAL)
 626                     || (arg->common.flags & ACPI_PARSEOP_IN_STACK)) {
 627                         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 628                                           "Argument previously created, already stacked\n"));
 629
 630                         ACPI_DEBUGGER_EXEC(acpi_db_display_argument_object
 631                                            (walk_state->
 632                                             operands[walk_state->num_operands -
 633                                                      1], walk_state));
 634
 635                         /*
 636                          * Use value that was already previously returned
 637                          * by the evaluation of this argument
 638                          */
 639                         status = acpi_ds_result_pop(&obj_desc, walk_state);
 640                         if (ACPI_FAILURE(status)) {
 641                                 /*
 642                                  * Only error is underflow, and this indicates
 643                                  * a missing or null operand!
 644                                  */
 645                                 ACPI_EXCEPTION((AE_INFO, status,
 646                                                 "Missing or null operand"));
 647                                 return_ACPI_STATUS(status);
 648                         }
 649                 } else {
 650                         /* Create an ACPI_INTERNAL_OBJECT for the argument */
 651
 652                         obj_desc =
 653                             acpi_ut_create_internal_object(op_info->
 654                                                            object_type);
 655                         if (!obj_desc) {
 656                                 return_ACPI_STATUS(AE_NO_MEMORY);
 657                         }
 658
 659                         /* Initialize the new object */
 660
 661                         status =
 662                             acpi_ds_init_object_from_op(walk_state, arg, opcode,
 663                                                         &obj_desc);
 664                         if (ACPI_FAILURE(status)) {
 665                                 acpi_ut_delete_object_desc(obj_desc);
 666                                 return_ACPI_STATUS(status);
 667                         }
 668                 }
 669
 670                 /* Put the operand object on the object stack */
 671
 672                 status = acpi_ds_obj_stack_push(obj_desc, walk_state);
 673                 if (ACPI_FAILURE(status)) {
 674                         return_ACPI_STATUS(status);
 675                 }
 676
 677                 ACPI_DEBUGGER_EXEC(acpi_db_display_argument_object
 678                                    (obj_desc, walk_state));
 679         }
 680
 681         return_ACPI_STATUS(AE_OK);
 682 }
 683
 684 /*******************************************************************************
 685  *
 686  * FUNCTION:    acpi_ds_create_operands
 687  *
 688  * PARAMETERS:  walk_state          - Current state
 689  *              first_arg           - First argument of a parser argument tree
 690  *
 691  * RETURN:      Status
 692  *
 693  * DESCRIPTION: Convert an operator's arguments from a parse tree format to
 694  *              namespace objects and place those argument object on the object
 695  *              stack in preparation for evaluation by the interpreter.
 696  *
 697  ******************************************************************************/
 698
 699 acpi_status
 700 acpi_ds_create_operands(struct acpi_walk_state *walk_state,
 701                         union acpi_parse_object *first_arg)
 702 {
 703         acpi_status status = AE_OK;
 704         union acpi_parse_object *arg;
 705         union acpi_parse_object *arguments[ACPI_OBJ_NUM_OPERANDS];
 706         u32 arg_count = 0;
 707         u32 index = walk_state->num_operands;
 708         u32 i;
 709
 710         ACPI_FUNCTION_TRACE_PTR(ds_create_operands, first_arg);
 711
 712         /* Get all arguments in the list */
 713
 714         arg = first_arg;
 715         while (arg) {
 716                 if (index >= ACPI_OBJ_NUM_OPERANDS) {
 717                         return_ACPI_STATUS(AE_BAD_DATA);
 718                 }
 719
 720                 arguments[index] = arg;
 721                 walk_state->operands[index] = NULL;
 722
 723                 /* Move on to next argument, if any */
 724
 725                 arg = arg->common.next;
 726                 arg_count++;
 727                 index++;
 728         }
 729
 730         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 731                           "NumOperands %d, ArgCount %d, Index %d\n",
 732                           walk_state->num_operands, arg_count, index));
 733
 734         /* Create the interpreter arguments, in reverse order */
 735
 736         index--;
 737         for (i = 0; i < arg_count; i++) {
 738                 arg = arguments[index];
 739                 walk_state->operand_index = (u8)index;
 740
 741                 status = acpi_ds_create_operand(walk_state, arg, index);
 742                 if (ACPI_FAILURE(status)) {
 743                         goto cleanup;
 744                 }
 745
 746                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 747                                   "Created Arg #%u (%p) %u args total\n",
 748                                   index, arg, arg_count));
 749                 index--;
 750         }
 751
 752         return_ACPI_STATUS(status);
 753
 754 cleanup:
 755         /*
 756          * We must undo everything done above; meaning that we must
 757          * pop everything off of the operand stack and delete those
 758          * objects
 759          */
 760         acpi_ds_obj_stack_pop_and_delete(arg_count, walk_state);
 761
 762         ACPI_EXCEPTION((AE_INFO, status, "While creating Arg %u", index));
 763         return_ACPI_STATUS(status);
 764 }
 765
 766 /*****************************************************************************
 767  *
 768  * FUNCTION:    acpi_ds_evaluate_name_path
 769  *
 770  * PARAMETERS:  walk_state      - Current state of the parse tree walk,
 771  *                                the opcode of current operation should be
 772  *                                AML_INT_NAMEPATH_OP
 773  *
 774  * RETURN:      Status
 775  *
 776  * DESCRIPTION: Translate the -name_path- parse tree object to the equivalent
 777  *              interpreter object, convert it to value, if needed, duplicate
 778  *              it, if needed, and push it onto the current result stack.
 779  *
 780  ****************************************************************************/
 781
 782 acpi_status acpi_ds_evaluate_name_path(struct acpi_walk_state *walk_state)
 783 {
 784         acpi_status status = AE_OK;
 785         union acpi_parse_object *op = walk_state->op;
 786         union acpi_operand_object **operand = &walk_state->operands[0];
 787         union acpi_operand_object *new_obj_desc;
 788         u8 type;
 789
 790         ACPI_FUNCTION_TRACE_PTR(ds_evaluate_name_path, walk_state);
 791
 792         if (!op->common.parent) {
 793
 794                 /* This happens after certain exception processing */
 795
 796                 goto exit;
 797         }
 798
 799         if ((op->common.parent->common.aml_opcode == AML_PACKAGE_OP) ||
 800             (op->common.parent->common.aml_opcode == AML_VAR_PACKAGE_OP) ||
 801             (op->common.parent->common.aml_opcode == AML_REF_OF_OP)) {
 802
 803                 /* TBD: Should we specify this feature as a bit of op_info->Flags of these opcodes? */
 804
 805                 goto exit;
 806         }
 807
 808         status = acpi_ds_create_operand(walk_state, op, 0);
 809         if (ACPI_FAILURE(status)) {
 810                 goto exit;
 811         }
 812
 813         if (op->common.flags & ACPI_PARSEOP_TARGET) {
 814                 new_obj_desc = *operand;
 815                 goto push_result;
 816         }
 817
 818         type = (*operand)->common.type;
 819
 820         status = acpi_ex_resolve_to_value(operand, walk_state);
 821         if (ACPI_FAILURE(status)) {
 822                 goto exit;
 823         }
 824
 825         if (type == ACPI_TYPE_INTEGER) {
 826
 827                 /* It was incremented by acpi_ex_resolve_to_value */
 828
 829                 acpi_ut_remove_reference(*operand);
 830
 831                 status =
 832                     acpi_ut_copy_iobject_to_iobject(*operand, &new_obj_desc,
 833                                                     walk_state);
 834                 if (ACPI_FAILURE(status)) {
 835                         goto exit;
 836                 }
 837         } else {
 838                 /*
 839                  * The object either was anew created or is
 840                  * a Namespace node - don't decrement it.
 841                  */
 842                 new_obj_desc = *operand;
 843         }
 844
 845         /* Cleanup for name-path operand */
 846
 847         status = acpi_ds_obj_stack_pop(1, walk_state);
 848         if (ACPI_FAILURE(status)) {
 849                 walk_state->result_obj = new_obj_desc;
 850                 goto exit;
 851         }
 852
 853 push_result:
 854
 855         walk_state->result_obj = new_obj_desc;
 856
 857         status = acpi_ds_result_push(walk_state->result_obj, walk_state);
 858         if (ACPI_SUCCESS(status)) {
 859
 860                 /* Force to take it from stack */
 861
 862                 op->common.flags |= ACPI_PARSEOP_IN_STACK;
 863         }
 864
 865 exit:
 866
 867         return_ACPI_STATUS(status);
 868 }