drivers/acpi/dispatcher/dsutils.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: dsutils - Dispatcher utilities
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2007, R. Byron Moore
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include <acpi/acparser.h>
  46 #include <acpi/amlcode.h>
  47 #include <acpi/acdispat.h>
  48 #include <acpi/acinterp.h>
  49 #include <acpi/acnamesp.h>
  50 #include <acpi/acdebug.h>
  51
  52 #define _COMPONENT          ACPI_DISPATCHER
  53 ACPI_MODULE_NAME("dsutils")
  54
  55 /*******************************************************************************
  56  *
  57  * FUNCTION:    acpi_ds_clear_implicit_return
  58  *
  59  * PARAMETERS:  walk_state          - Current State
  60  *
  61  * RETURN:      None.
  62  *
  63  * DESCRIPTION: Clear and remove a reference on an implicit return value.  Used
  64  *              to delete "stale" return values (if enabled, the return value
  65  *              from every operator is saved at least momentarily, in case the
  66  *              parent method exits.)
  67  *
  68  ******************************************************************************/
  69 void acpi_ds_clear_implicit_return(struct acpi_walk_state *walk_state)
  70 {
  71         ACPI_FUNCTION_NAME(ds_clear_implicit_return);
  72
  73         /*
  74          * Slack must be enabled for this feature
  75          */
  76         if (!acpi_gbl_enable_interpreter_slack) {
  77                 return;
  78         }
  79
  80         if (walk_state->implicit_return_obj) {
  81                 /*
  82                  * Delete any "stale" implicit return. However, in
  83                  * complex statements, the implicit return value can be
  84                  * bubbled up several levels.
  85                  */
  86                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
  87                                   "Removing reference on stale implicit return obj %p\n",
  88                                   walk_state->implicit_return_obj));
  89
  90                 acpi_ut_remove_reference(walk_state->implicit_return_obj);
  91                 walk_state->implicit_return_obj = NULL;
  92         }
  93 }
  94
  95 #ifndef ACPI_NO_METHOD_EXECUTION
  96 /*******************************************************************************
  97  *
  98  * FUNCTION:    acpi_ds_do_implicit_return
  99  *
 100  * PARAMETERS:  return_desc         - The return value
 101  *              walk_state          - Current State
 102  *              add_reference       - True if a reference should be added to the
 103  *                                    return object
 104  *
 105  * RETURN:      TRUE if implicit return enabled, FALSE otherwise
 106  *
 107  * DESCRIPTION: Implements the optional "implicit return".  We save the result
 108  *              of every ASL operator and control method invocation in case the
 109  *              parent method exit.  Before storing a new return value, we
 110  *              delete the previous return value.
 111  *
 112  ******************************************************************************/
 113
 114 u8
 115 acpi_ds_do_implicit_return(union acpi_operand_object *return_desc,
 116                            struct acpi_walk_state *walk_state, u8 add_reference)
 117 {
 118         ACPI_FUNCTION_NAME(ds_do_implicit_return);
 119
 120         /*
 121          * Slack must be enabled for this feature, and we must
 122          * have a valid return object
 123          */
 124         if ((!acpi_gbl_enable_interpreter_slack) || (!return_desc)) {
 125                 return (FALSE);
 126         }
 127
 128         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 129                           "Result %p will be implicitly returned; Prev=%p\n",
 130                           return_desc, walk_state->implicit_return_obj));
 131
 132         /*
 133          * Delete any "stale" implicit return value first. However, in
 134          * complex statements, the implicit return value can be
 135          * bubbled up several levels, so we don't clear the value if it
 136          * is the same as the return_desc.
 137          */
 138         if (walk_state->implicit_return_obj) {
 139                 if (walk_state->implicit_return_obj == return_desc) {
 140                         return (TRUE);
 141                 }
 142                 acpi_ds_clear_implicit_return(walk_state);
 143         }
 144
 145         /* Save the implicit return value, add a reference if requested */
 146
 147         walk_state->implicit_return_obj = return_desc;
 148         if (add_reference) {
 149                 acpi_ut_add_reference(return_desc);
 150         }
 151
 152         return (TRUE);
 153 }
 154
 155 /*******************************************************************************
 156  *
 157  * FUNCTION:    acpi_ds_is_result_used
 158  *
 159  * PARAMETERS:  Op                  - Current Op
 160  *              walk_state          - Current State
 161  *
 162  * RETURN:      TRUE if result is used, FALSE otherwise
 163  *
 164  * DESCRIPTION: Check if a result object will be used by the parent
 165  *
 166  ******************************************************************************/
 167
 168 u8
 169 acpi_ds_is_result_used(union acpi_parse_object * op,
 170                        struct acpi_walk_state * walk_state)
 171 {
 172         const struct acpi_opcode_info *parent_info;
 173
 174         ACPI_FUNCTION_TRACE_PTR(ds_is_result_used, op);
 175
 176         /* Must have both an Op and a Result Object */
 177
 178         if (!op) {
 179                 ACPI_ERROR((AE_INFO, "Null Op"));
 180                 return_UINT8(TRUE);
 181         }
 182
 183         /*
 184          * We know that this operator is not a
 185          * Return() operator (would not come here.) The following code is the
 186          * optional support for a so-called "implicit return". Some AML code
 187          * assumes that the last value of the method is "implicitly" returned
 188          * to the caller. Just save the last result as the return value.
 189          * NOTE: this is optional because the ASL language does not actually
 190          * support this behavior.
 191          */
 192         (void)acpi_ds_do_implicit_return(walk_state->result_obj, walk_state,
 193                                          TRUE);
 194
 195         /*
 196          * Now determine if the parent will use the result
 197          *
 198          * If there is no parent, or the parent is a scope_op, we are executing
 199          * at the method level. An executing method typically has no parent,
 200          * since each method is parsed separately.  A method invoked externally
 201          * via execute_control_method has a scope_op as the parent.
 202          */
 203         if ((!op->common.parent) ||
 204             (op->common.parent->common.aml_opcode == AML_SCOPE_OP)) {
 205
 206                 /* No parent, the return value cannot possibly be used */
 207
 208                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 209                                   "At Method level, result of [%s] not used\n",
 210                                   acpi_ps_get_opcode_name(op->common.
 211                                                           aml_opcode)));
 212                 return_UINT8(FALSE);
 213         }
 214
 215         /* Get info on the parent. The root_op is AML_SCOPE */
 216
 217         parent_info =
 218             acpi_ps_get_opcode_info(op->common.parent->common.aml_opcode);
 219         if (parent_info->class == AML_CLASS_UNKNOWN) {
 220                 ACPI_ERROR((AE_INFO, "Unknown parent opcode Op=%p", op));
 221                 return_UINT8(FALSE);
 222         }
 223
 224         /*
 225          * Decide what to do with the result based on the parent.  If
 226          * the parent opcode will not use the result, delete the object.
 227          * Otherwise leave it as is, it will be deleted when it is used
 228          * as an operand later.
 229          */
 230         switch (parent_info->class) {
 231         case AML_CLASS_CONTROL:
 232
 233                 switch (op->common.parent->common.aml_opcode) {
 234                 case AML_RETURN_OP:
 235
 236                         /* Never delete the return value associated with a return opcode */
 237
 238                         goto result_used;
 239
 240                 case AML_IF_OP:
 241                 case AML_WHILE_OP:
 242
 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                         /* Ignore other control opcodes */
 257                         break;
 258                 }
 259
 260                 /* The general control opcode returns no result */
 261
 262                 goto result_not_used;
 263
 264         case AML_CLASS_CREATE:
 265
 266                 /*
 267                  * These opcodes allow term_arg(s) as operands and therefore
 268                  * the operands can be method calls.  The result is used.
 269                  */
 270                 goto result_used;
 271
 272         case AML_CLASS_NAMED_OBJECT:
 273
 274                 if ((op->common.parent->common.aml_opcode == AML_REGION_OP) ||
 275                     (op->common.parent->common.aml_opcode == AML_DATA_REGION_OP)
 276                     || (op->common.parent->common.aml_opcode == AML_PACKAGE_OP)
 277                     || (op->common.parent->common.aml_opcode ==
 278                         AML_VAR_PACKAGE_OP)
 279                     || (op->common.parent->common.aml_opcode == AML_BUFFER_OP)
 280                     || (op->common.parent->common.aml_opcode ==
 281                         AML_INT_EVAL_SUBTREE_OP)) {
 282                         /*
 283                          * These opcodes allow term_arg(s) as operands and therefore
 284                          * the operands can be method calls.  The result is used.
 285                          */
 286                         goto result_used;
 287                 }
 288
 289                 goto result_not_used;
 290
 291         default:
 292
 293                 /*
 294                  * In all other cases. the parent will actually use the return
 295                  * object, so keep it.
 296                  */
 297                 goto result_used;
 298         }
 299
 300       result_used:
 301         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 302                           "Result of [%s] used by Parent [%s] Op=%p\n",
 303                           acpi_ps_get_opcode_name(op->common.aml_opcode),
 304                           acpi_ps_get_opcode_name(op->common.parent->common.
 305                                                   aml_opcode), op));
 306
 307         return_UINT8(TRUE);
 308
 309       result_not_used:
 310         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 311                           "Result of [%s] not used by Parent [%s] Op=%p\n",
 312                           acpi_ps_get_opcode_name(op->common.aml_opcode),
 313                           acpi_ps_get_opcode_name(op->common.parent->common.
 314                                                   aml_opcode), op));
 315
 316         return_UINT8(FALSE);
 317 }
 318
 319 /*******************************************************************************
 320  *
 321  * FUNCTION:    acpi_ds_delete_result_if_not_used
 322  *
 323  * PARAMETERS:  Op              - Current parse Op
 324  *              result_obj      - Result of the operation
 325  *              walk_state      - Current state
 326  *
 327  * RETURN:      Status
 328  *
 329  * DESCRIPTION: Used after interpretation of an opcode.  If there is an internal
 330  *              result descriptor, check if the parent opcode will actually use
 331  *              this result.  If not, delete the result now so that it will
 332  *              not become orphaned.
 333  *
 334  ******************************************************************************/
 335
 336 void
 337 acpi_ds_delete_result_if_not_used(union acpi_parse_object *op,
 338                                   union acpi_operand_object *result_obj,
 339                                   struct acpi_walk_state *walk_state)
 340 {
 341         union acpi_operand_object *obj_desc;
 342         acpi_status status;
 343
 344         ACPI_FUNCTION_TRACE_PTR(ds_delete_result_if_not_used, result_obj);
 345
 346         if (!op) {
 347                 ACPI_ERROR((AE_INFO, "Null Op"));
 348                 return_VOID;
 349         }
 350
 351         if (!result_obj) {
 352                 return_VOID;
 353         }
 354
 355         if (!acpi_ds_is_result_used(op, walk_state)) {
 356
 357                 /* Must pop the result stack (obj_desc should be equal to result_obj) */
 358
 359                 status = acpi_ds_result_pop(&obj_desc, walk_state);
 360                 if (ACPI_SUCCESS(status)) {
 361                         acpi_ut_remove_reference(result_obj);
 362                 }
 363         }
 364
 365         return_VOID;
 366 }
 367
 368 /*******************************************************************************
 369  *
 370  * FUNCTION:    acpi_ds_resolve_operands
 371  *
 372  * PARAMETERS:  walk_state          - Current walk state with operands on stack
 373  *
 374  * RETURN:      Status
 375  *
 376  * DESCRIPTION: Resolve all operands to their values.  Used to prepare
 377  *              arguments to a control method invocation (a call from one
 378  *              method to another.)
 379  *
 380  ******************************************************************************/
 381
 382 acpi_status acpi_ds_resolve_operands(struct acpi_walk_state *walk_state)
 383 {
 384         u32 i;
 385         acpi_status status = AE_OK;
 386
 387         ACPI_FUNCTION_TRACE_PTR(ds_resolve_operands, walk_state);
 388
 389         /*
 390          * Attempt to resolve each of the valid operands
 391          * Method arguments are passed by reference, not by value.  This means
 392          * that the actual objects are passed, not copies of the objects.
 393          */
 394         for (i = 0; i < walk_state->num_operands; i++) {
 395                 status =
 396                     acpi_ex_resolve_to_value(&walk_state->operands[i],
 397                                              walk_state);
 398                 if (ACPI_FAILURE(status)) {
 399                         break;
 400                 }
 401         }
 402
 403         return_ACPI_STATUS(status);
 404 }
 405
 406 /*******************************************************************************
 407  *
 408  * FUNCTION:    acpi_ds_clear_operands
 409  *
 410  * PARAMETERS:  walk_state          - Current walk state with operands on stack
 411  *
 412  * RETURN:      None
 413  *
 414  * DESCRIPTION: Clear all operands on the current walk state operand stack.
 415  *
 416  ******************************************************************************/
 417
 418 void acpi_ds_clear_operands(struct acpi_walk_state *walk_state)
 419 {
 420         u32 i;
 421
 422         ACPI_FUNCTION_TRACE_PTR(ds_clear_operands, walk_state);
 423
 424         /* Remove a reference on each operand on the stack */
 425
 426         for (i = 0; i < walk_state->num_operands; i++) {
 427                 /*
 428                  * Remove a reference to all operands, including both
 429                  * "Arguments" and "Targets".
 430                  */
 431                 acpi_ut_remove_reference(walk_state->operands[i]);
 432                 walk_state->operands[i] = NULL;
 433         }
 434
 435         walk_state->num_operands = 0;
 436         return_VOID;
 437 }
 438 #endif
 439
 440 /*******************************************************************************
 441  *
 442  * FUNCTION:    acpi_ds_create_operand
 443  *
 444  * PARAMETERS:  walk_state      - Current walk state
 445  *              Arg             - Parse object for the argument
 446  *              arg_index       - Which argument (zero based)
 447  *
 448  * RETURN:      Status
 449  *
 450  * DESCRIPTION: Translate a parse tree object that is an argument to an AML
 451  *              opcode to the equivalent interpreter object.  This may include
 452  *              looking up a name or entering a new name into the internal
 453  *              namespace.
 454  *
 455  ******************************************************************************/
 456
 457 acpi_status
 458 acpi_ds_create_operand(struct acpi_walk_state *walk_state,
 459                        union acpi_parse_object *arg, u32 arg_index)
 460 {
 461         acpi_status status = AE_OK;
 462         char *name_string;
 463         u32 name_length;
 464         union acpi_operand_object *obj_desc;
 465         union acpi_parse_object *parent_op;
 466         u16 opcode;
 467         acpi_interpreter_mode interpreter_mode;
 468         const struct acpi_opcode_info *op_info;
 469
 470         ACPI_FUNCTION_TRACE_PTR(ds_create_operand, arg);
 471
 472         /* A valid name must be looked up in the namespace */
 473
 474         if ((arg->common.aml_opcode == AML_INT_NAMEPATH_OP) &&
 475             (arg->common.value.string) &&
 476             !(arg->common.flags & ACPI_PARSEOP_IN_STACK)) {
 477                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Getting a name: Arg=%p\n",
 478                                   arg));
 479
 480                 /* Get the entire name string from the AML stream */
 481
 482                 status =
 483                     acpi_ex_get_name_string(ACPI_TYPE_ANY,
 484                                             arg->common.value.buffer,
 485                                             &name_string, &name_length);
 486
 487                 if (ACPI_FAILURE(status)) {
 488                         return_ACPI_STATUS(status);
 489                 }
 490
 491                 /* All prefixes have been handled, and the name is in name_string */
 492
 493                 /*
 494                  * Special handling for buffer_field declarations. This is a deferred
 495                  * opcode that unfortunately defines the field name as the last
 496                  * parameter instead of the first.  We get here when we are performing
 497                  * the deferred execution, so the actual name of the field is already
 498                  * in the namespace.  We don't want to attempt to look it up again
 499                  * because we may be executing in a different scope than where the
 500                  * actual opcode exists.
 501                  */
 502                 if ((walk_state->deferred_node) &&
 503                     (walk_state->deferred_node->type == ACPI_TYPE_BUFFER_FIELD)
 504                     && (arg_index ==
 505                         (u32) ((walk_state->opcode ==
 506                                 AML_CREATE_FIELD_OP) ? 3 : 2))) {
 507                         obj_desc =
 508                             ACPI_CAST_PTR(union acpi_operand_object,
 509                                           walk_state->deferred_node);
 510                         status = AE_OK;
 511                 } else {        /* All other opcodes */
 512
 513                         /*
 514                          * Differentiate between a namespace "create" operation
 515                          * versus a "lookup" operation (IMODE_LOAD_PASS2 vs.
 516                          * IMODE_EXECUTE) in order to support the creation of
 517                          * namespace objects during the execution of control methods.
 518                          */
 519                         parent_op = arg->common.parent;
 520                         op_info =
 521                             acpi_ps_get_opcode_info(parent_op->common.
 522                                                     aml_opcode);
 523                         if ((op_info->flags & AML_NSNODE)
 524                             && (parent_op->common.aml_opcode !=
 525                                 AML_INT_METHODCALL_OP)
 526                             && (parent_op->common.aml_opcode != AML_REGION_OP)
 527                             && (parent_op->common.aml_opcode !=
 528                                 AML_INT_NAMEPATH_OP)) {
 529
 530                                 /* Enter name into namespace if not found */
 531
 532                                 interpreter_mode = ACPI_IMODE_LOAD_PASS2;
 533                         } else {
 534                                 /* Return a failure if name not found */
 535
 536                                 interpreter_mode = ACPI_IMODE_EXECUTE;
 537                         }
 538
 539                         status =
 540                             acpi_ns_lookup(walk_state->scope_info, name_string,
 541                                            ACPI_TYPE_ANY, interpreter_mode,
 542                                            ACPI_NS_SEARCH_PARENT |
 543                                            ACPI_NS_DONT_OPEN_SCOPE, walk_state,
 544                                            ACPI_CAST_INDIRECT_PTR(struct
 545                                                                   acpi_namespace_node,
 546                                                                   &obj_desc));
 547                         /*
 548                          * The only case where we pass through (ignore) a NOT_FOUND
 549                          * error is for the cond_ref_of opcode.
 550                          */
 551                         if (status == AE_NOT_FOUND) {
 552                                 if (parent_op->common.aml_opcode ==
 553                                     AML_COND_REF_OF_OP) {
 554                                         /*
 555                                          * For the Conditional Reference op, it's OK if
 556                                          * the name is not found;  We just need a way to
 557                                          * indicate this to the interpreter, set the
 558                                          * object to the root
 559                                          */
 560                                         obj_desc = ACPI_CAST_PTR(union
 561                                                                  acpi_operand_object,
 562                                                                  acpi_gbl_root_node);
 563                                         status = AE_OK;
 564                                 } else {
 565                                         /*
 566                                          * We just plain didn't find it -- which is a
 567                                          * very serious error at this point
 568                                          */
 569                                         status = AE_AML_NAME_NOT_FOUND;
 570                                 }
 571                         }
 572
 573                         if (ACPI_FAILURE(status)) {
 574                                 ACPI_ERROR_NAMESPACE(name_string, status);
 575                         }
 576                 }
 577
 578                 /* Free the namestring created above */
 579
 580                 ACPI_FREE(name_string);
 581
 582                 /* Check status from the lookup */
 583
 584                 if (ACPI_FAILURE(status)) {
 585                         return_ACPI_STATUS(status);
 586                 }
 587
 588                 /* Put the resulting object onto the current object stack */
 589
 590                 status = acpi_ds_obj_stack_push(obj_desc, walk_state);
 591                 if (ACPI_FAILURE(status)) {
 592                         return_ACPI_STATUS(status);
 593                 }
 594                 ACPI_DEBUGGER_EXEC(acpi_db_display_argument_object
 595                                    (obj_desc, walk_state));
 596         } else {
 597                 /* Check for null name case */
 598
 599                 if ((arg->common.aml_opcode == AML_INT_NAMEPATH_OP) &&
 600                     !(arg->common.flags & ACPI_PARSEOP_IN_STACK)) {
 601                         /*
 602                          * If the name is null, this means that this is an
 603                          * optional result parameter that was not specified
 604                          * in the original ASL.  Create a Zero Constant for a
 605                          * placeholder.  (Store to a constant is a Noop.)
 606                          */
 607                         opcode = AML_ZERO_OP;   /* Has no arguments! */
 608
 609                         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 610                                           "Null namepath: Arg=%p\n", arg));
 611                 } else {
 612                         opcode = arg->common.aml_opcode;
 613                 }
 614
 615                 /* Get the object type of the argument */
 616
 617                 op_info = acpi_ps_get_opcode_info(opcode);
 618                 if (op_info->object_type == ACPI_TYPE_INVALID) {
 619                         return_ACPI_STATUS(AE_NOT_IMPLEMENTED);
 620                 }
 621
 622                 if ((op_info->flags & AML_HAS_RETVAL)
 623                     || (arg->common.flags & ACPI_PARSEOP_IN_STACK)) {
 624                         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 625                                           "Argument previously created, already stacked\n"));
 626
 627                         ACPI_DEBUGGER_EXEC(acpi_db_display_argument_object
 628                                            (walk_state->
 629                                             operands[walk_state->num_operands -
 630                                                      1], walk_state));
 631
 632                         /*
 633                          * Use value that was already previously returned
 634                          * by the evaluation of this argument
 635                          */
 636                         status = acpi_ds_result_pop(&obj_desc, walk_state);
 637                         if (ACPI_FAILURE(status)) {
 638                                 /*
 639                                  * Only error is underflow, and this indicates
 640                                  * a missing or null operand!
 641                                  */
 642                                 ACPI_EXCEPTION((AE_INFO, status,
 643                                                 "Missing or null operand"));
 644                                 return_ACPI_STATUS(status);
 645                         }
 646                 } else {
 647                         /* Create an ACPI_INTERNAL_OBJECT for the argument */
 648
 649                         obj_desc =
 650                             acpi_ut_create_internal_object(op_info->
 651                                                            object_type);
 652                         if (!obj_desc) {
 653                                 return_ACPI_STATUS(AE_NO_MEMORY);
 654                         }
 655
 656                         /* Initialize the new object */
 657
 658                         status =
 659                             acpi_ds_init_object_from_op(walk_state, arg, opcode,
 660                                                         &obj_desc);
 661                         if (ACPI_FAILURE(status)) {
 662                                 acpi_ut_delete_object_desc(obj_desc);
 663                                 return_ACPI_STATUS(status);
 664                         }
 665                 }
 666
 667                 /* Put the operand object on the object stack */
 668
 669                 status = acpi_ds_obj_stack_push(obj_desc, walk_state);
 670                 if (ACPI_FAILURE(status)) {
 671                         return_ACPI_STATUS(status);
 672                 }
 673
 674                 ACPI_DEBUGGER_EXEC(acpi_db_display_argument_object
 675                                    (obj_desc, walk_state));
 676         }
 677
 678         return_ACPI_STATUS(AE_OK);
 679 }
 680
 681 /*******************************************************************************
 682  *
 683  * FUNCTION:    acpi_ds_create_operands
 684  *
 685  * PARAMETERS:  walk_state          - Current state
 686  *              first_arg           - First argument of a parser argument tree
 687  *
 688  * RETURN:      Status
 689  *
 690  * DESCRIPTION: Convert an operator's arguments from a parse tree format to
 691  *              namespace objects and place those argument object on the object
 692  *              stack in preparation for evaluation by the interpreter.
 693  *
 694  ******************************************************************************/
 695
 696 acpi_status
 697 acpi_ds_create_operands(struct acpi_walk_state *walk_state,
 698                         union acpi_parse_object *first_arg)
 699 {
 700         acpi_status status = AE_OK;
 701         union acpi_parse_object *arg;
 702         union acpi_parse_object *arguments[ACPI_OBJ_NUM_OPERANDS];
 703         u8 arg_count = 0;
 704         u8 count = 0;
 705         u8 index = walk_state->num_operands;
 706         u8 i;
 707
 708         ACPI_FUNCTION_TRACE_PTR(ds_create_operands, first_arg);
 709
 710         /* Get all arguments in the list */
 711
 712         arg = first_arg;
 713         while (arg) {
 714                 if (index >= ACPI_OBJ_NUM_OPERANDS) {
 715                         return_ACPI_STATUS(AE_BAD_DATA);
 716                 }
 717
 718                 arguments[index] = arg;
 719                 walk_state->operands[index] = NULL;
 720
 721                 /* Move on to next argument, if any */
 722
 723                 arg = arg->common.next;
 724                 arg_count++;
 725                 index++;
 726         }
 727
 728         index--;
 729
 730         /* It is the appropriate order to get objects from the Result stack */
 731
 732         for (i = 0; i < arg_count; i++) {
 733                 arg = arguments[index];
 734
 735                 /* Force the filling of the operand stack in inverse order */
 736
 737                 walk_state->operand_index = index;
 738
 739                 status = acpi_ds_create_operand(walk_state, arg, index);
 740                 if (ACPI_FAILURE(status)) {
 741                         goto cleanup;
 742                 }
 743
 744                 count++;
 745                 index--;
 746
 747                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 748                                   "Arg #%d (%p) done, Arg1=%p\n", index, arg,
 749                                   first_arg));
 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 %d", 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 = ACPI_GET_OBJECT_TYPE(*operand);
 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 }