drivers/bus/acpi/acpica/dispatcher/dsutils.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: dsutils - Dispatcher utilities
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2018, 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.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  *
  59  * FUNCTION:    AcpiDsClearImplicitReturn
  60  *
  61  * PARAMETERS:  WalkState           - Current State
  62  *
  63  * RETURN:      None.
  64  *
  65  * DESCRIPTION: Clear and remove a reference on an implicit return value. Used
  66  *              to delete "stale" return values (if enabled, the return value
  67  *              from every operator is saved at least momentarily, in case the
  68  *              parent method exits.)
  69  *
  70  ******************************************************************************/
  71
  72 void
  73 AcpiDsClearImplicitReturn (
  74     ACPI_WALK_STATE         *WalkState)
  75 {
  76     ACPI_FUNCTION_NAME (DsClearImplicitReturn);
  77
  78
  79     /*
  80      * Slack must be enabled for this feature
  81      */
  82     if (!AcpiGbl_EnableInterpreterSlack)
  83     {
  84         return;
  85     }
  86
  87     if (WalkState->ImplicitReturnObj)
  88     {
  89         /*
  90          * Delete any "stale" implicit return. However, in
  91          * complex statements, the implicit return value can be
  92          * bubbled up several levels.
  93          */
  94         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
  95             "Removing reference on stale implicit return obj %p\n",
  96             WalkState->ImplicitReturnObj));
  97
  98         AcpiUtRemoveReference (WalkState->ImplicitReturnObj);
  99         WalkState->ImplicitReturnObj = NULL;
 100     }
 101 }
 102
 103
 104 /*******************************************************************************
 105  *
 106  * FUNCTION:    AcpiDsDoImplicitReturn
 107  *
 108  * PARAMETERS:  ReturnDesc          - The return value
 109  *              WalkState           - Current State
 110  *              AddReference        - True if a reference should be added to the
 111  *                                    return object
 112  *
 113  * RETURN:      TRUE if implicit return enabled, FALSE otherwise
 114  *
 115  * DESCRIPTION: Implements the optional "implicit return".  We save the result
 116  *              of every ASL operator and control method invocation in case the
 117  *              parent method exit. Before storing a new return value, we
 118  *              delete the previous return value.
 119  *
 120  ******************************************************************************/
 121
 122 BOOLEAN
 123 AcpiDsDoImplicitReturn (
 124     ACPI_OPERAND_OBJECT     *ReturnDesc,
 125     ACPI_WALK_STATE         *WalkState,
 126     BOOLEAN                 AddReference)
 127 {
 128     ACPI_FUNCTION_NAME (DsDoImplicitReturn);
 129
 130
 131     /*
 132      * Slack must be enabled for this feature, and we must
 133      * have a valid return object
 134      */
 135     if ((!AcpiGbl_EnableInterpreterSlack) ||
 136         (!ReturnDesc))
 137     {
 138         return (FALSE);
 139     }
 140
 141     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 142         "Result %p will be implicitly returned; Prev=%p\n",
 143         ReturnDesc,
 144         WalkState->ImplicitReturnObj));
 145
 146     /*
 147      * Delete any "stale" implicit return value first. However, in
 148      * complex statements, the implicit return value can be
 149      * bubbled up several levels, so we don't clear the value if it
 150      * is the same as the ReturnDesc.
 151      */
 152     if (WalkState->ImplicitReturnObj)
 153     {
 154         if (WalkState->ImplicitReturnObj == ReturnDesc)
 155         {
 156             return (TRUE);
 157         }
 158         AcpiDsClearImplicitReturn (WalkState);
 159     }
 160
 161     /* Save the implicit return value, add a reference if requested */
 162
 163     WalkState->ImplicitReturnObj = ReturnDesc;
 164     if (AddReference)
 165     {
 166         AcpiUtAddReference (ReturnDesc);
 167     }
 168
 169     return (TRUE);
 170 }
 171
 172
 173 /*******************************************************************************
 174  *
 175  * FUNCTION:    AcpiDsIsResultUsed
 176  *
 177  * PARAMETERS:  Op                  - Current Op
 178  *              WalkState           - Current State
 179  *
 180  * RETURN:      TRUE if result is used, FALSE otherwise
 181  *
 182  * DESCRIPTION: Check if a result object will be used by the parent
 183  *
 184  ******************************************************************************/
 185
 186 BOOLEAN
 187 AcpiDsIsResultUsed (
 188     ACPI_PARSE_OBJECT       *Op,
 189     ACPI_WALK_STATE         *WalkState)
 190 {
 191     const ACPI_OPCODE_INFO  *ParentInfo;
 192
 193     ACPI_FUNCTION_TRACE_PTR (DsIsResultUsed, Op);
 194
 195
 196     /* Must have both an Op and a Result Object */
 197
 198     if (!Op)
 199     {
 200         ACPI_ERROR ((AE_INFO, "Null Op"));
 201         return_UINT8 (TRUE);
 202     }
 203
 204     /*
 205      * We know that this operator is not a
 206      * Return() operator (would not come here.) The following code is the
 207      * optional support for a so-called "implicit return". Some AML code
 208      * assumes that the last value of the method is "implicitly" returned
 209      * to the caller. Just save the last result as the return value.
 210      * NOTE: this is optional because the ASL language does not actually
 211      * support this behavior.
 212      */
 213     (void) AcpiDsDoImplicitReturn (WalkState->ResultObj, WalkState, TRUE);
 214
 215     /*
 216      * Now determine if the parent will use the result
 217      *
 218      * If there is no parent, or the parent is a ScopeOp, we are executing
 219      * at the method level. An executing method typically has no parent,
 220      * since each method is parsed separately. A method invoked externally
 221      * via ExecuteControlMethod has a ScopeOp as the parent.
 222      */
 223     if ((!Op->Common.Parent) ||
 224         (Op->Common.Parent->Common.AmlOpcode == AML_SCOPE_OP))
 225     {
 226         /* No parent, the return value cannot possibly be used */
 227
 228         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 229             "At Method level, result of [%s] not used\n",
 230             AcpiPsGetOpcodeName (Op->Common.AmlOpcode)));
 231         return_UINT8 (FALSE);
 232     }
 233
 234     /* Get info on the parent. The RootOp is AML_SCOPE */
 235
 236     ParentInfo = AcpiPsGetOpcodeInfo (Op->Common.Parent->Common.AmlOpcode);
 237     if (ParentInfo->Class == AML_CLASS_UNKNOWN)
 238     {
 239         ACPI_ERROR ((AE_INFO,
 240             "Unknown parent opcode Op=%p", Op));
 241         return_UINT8 (FALSE);
 242     }
 243
 244     /*
 245      * Decide what to do with the result based on the parent. If
 246      * the parent opcode will not use the result, delete the object.
 247      * Otherwise leave it as is, it will be deleted when it is used
 248      * as an operand later.
 249      */
 250     switch (ParentInfo->Class)
 251     {
 252     case AML_CLASS_CONTROL:
 253
 254         switch (Op->Common.Parent->Common.AmlOpcode)
 255         {
 256         case AML_RETURN_OP:
 257
 258             /* Never delete the return value associated with a return opcode */
 259
 260             goto ResultUsed;
 261
 262         case AML_IF_OP:
 263         case AML_WHILE_OP:
 264             /*
 265              * If we are executing the predicate AND this is the predicate op,
 266              * we will use the return value
 267              */
 268             if ((WalkState->ControlState->Common.State ==
 269                     ACPI_CONTROL_PREDICATE_EXECUTING) &&
 270                 (WalkState->ControlState->Control.PredicateOp == Op))
 271             {
 272                 goto ResultUsed;
 273             }
 274             break;
 275
 276         default:
 277
 278             /* Ignore other control opcodes */
 279
 280             break;
 281         }
 282
 283         /* The general control opcode returns no result */
 284
 285         goto ResultNotUsed;
 286
 287     case AML_CLASS_CREATE:
 288         /*
 289          * These opcodes allow TermArg(s) as operands and therefore
 290          * the operands can be method calls. The result is used.
 291          */
 292         goto ResultUsed;
 293
 294     case AML_CLASS_NAMED_OBJECT:
 295
 296         if ((Op->Common.Parent->Common.AmlOpcode == AML_REGION_OP)       ||
 297             (Op->Common.Parent->Common.AmlOpcode == AML_DATA_REGION_OP)  ||
 298             (Op->Common.Parent->Common.AmlOpcode == AML_PACKAGE_OP)      ||
 299             (Op->Common.Parent->Common.AmlOpcode == AML_BUFFER_OP)       ||
 300             (Op->Common.Parent->Common.AmlOpcode == AML_VARIABLE_PACKAGE_OP) ||
 301             (Op->Common.Parent->Common.AmlOpcode == AML_INT_EVAL_SUBTREE_OP) ||
 302             (Op->Common.Parent->Common.AmlOpcode == AML_BANK_FIELD_OP))
 303         {
 304             /*
 305              * These opcodes allow TermArg(s) as operands and therefore
 306              * the operands can be method calls. The result is used.
 307              */
 308             goto ResultUsed;
 309         }
 310
 311         goto ResultNotUsed;
 312
 313     default:
 314         /*
 315          * In all other cases. the parent will actually use the return
 316          * object, so keep it.
 317          */
 318         goto ResultUsed;
 319     }
 320
 321
 322 ResultUsed:
 323     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 324         "Result of [%s] used by Parent [%s] Op=%p\n",
 325         AcpiPsGetOpcodeName (Op->Common.AmlOpcode),
 326         AcpiPsGetOpcodeName (Op->Common.Parent->Common.AmlOpcode), Op));
 327
 328     return_UINT8 (TRUE);
 329
 330
 331 ResultNotUsed:
 332     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 333         "Result of [%s] not used by Parent [%s] Op=%p\n",
 334         AcpiPsGetOpcodeName (Op->Common.AmlOpcode),
 335         AcpiPsGetOpcodeName (Op->Common.Parent->Common.AmlOpcode), Op));
 336
 337     return_UINT8 (FALSE);
 338 }
 339
 340
 341 /*******************************************************************************
 342  *
 343  * FUNCTION:    AcpiDsDeleteResultIfNotUsed
 344  *
 345  * PARAMETERS:  Op              - Current parse Op
 346  *              ResultObj       - Result of the operation
 347  *              WalkState       - Current state
 348  *
 349  * RETURN:      Status
 350  *
 351  * DESCRIPTION: Used after interpretation of an opcode. If there is an internal
 352  *              result descriptor, check if the parent opcode will actually use
 353  *              this result. If not, delete the result now so that it will
 354  *              not become orphaned.
 355  *
 356  ******************************************************************************/
 357
 358 void
 359 AcpiDsDeleteResultIfNotUsed (
 360     ACPI_PARSE_OBJECT       *Op,
 361     ACPI_OPERAND_OBJECT     *ResultObj,
 362     ACPI_WALK_STATE         *WalkState)
 363 {
 364     ACPI_OPERAND_OBJECT     *ObjDesc;
 365     ACPI_STATUS             Status;
 366
 367
 368     ACPI_FUNCTION_TRACE_PTR (DsDeleteResultIfNotUsed, ResultObj);
 369
 370
 371     if (!Op)
 372     {
 373         ACPI_ERROR ((AE_INFO, "Null Op"));
 374         return_VOID;
 375     }
 376
 377     if (!ResultObj)
 378     {
 379         return_VOID;
 380     }
 381
 382     if (!AcpiDsIsResultUsed (Op, WalkState))
 383     {
 384         /* Must pop the result stack (ObjDesc should be equal to ResultObj) */
 385
 386         Status = AcpiDsResultPop (&ObjDesc, WalkState);
 387         if (ACPI_SUCCESS (Status))
 388         {
 389             AcpiUtRemoveReference (ResultObj);
 390         }
 391     }
 392
 393     return_VOID;
 394 }
 395
 396
 397 /*******************************************************************************
 398  *
 399  * FUNCTION:    AcpiDsResolveOperands
 400  *
 401  * PARAMETERS:  WalkState           - Current walk state with operands on stack
 402  *
 403  * RETURN:      Status
 404  *
 405  * DESCRIPTION: Resolve all operands to their values. Used to prepare
 406  *              arguments to a control method invocation (a call from one
 407  *              method to another.)
 408  *
 409  ******************************************************************************/
 410
 411 ACPI_STATUS
 412 AcpiDsResolveOperands (
 413     ACPI_WALK_STATE         *WalkState)
 414 {
 415     UINT32                  i;
 416     ACPI_STATUS             Status = AE_OK;
 417
 418
 419     ACPI_FUNCTION_TRACE_PTR (DsResolveOperands, WalkState);
 420
 421
 422     /*
 423      * Attempt to resolve each of the valid operands
 424      * Method arguments are passed by reference, not by value. This means
 425      * that the actual objects are passed, not copies of the objects.
 426      */
 427     for (i = 0; i < WalkState->NumOperands; i++)
 428     {
 429         Status = AcpiExResolveToValue (&WalkState->Operands[i], WalkState);
 430         if (ACPI_FAILURE (Status))
 431         {
 432             break;
 433         }
 434     }
 435
 436     return_ACPI_STATUS (Status);
 437 }
 438
 439
 440 /*******************************************************************************
 441  *
 442  * FUNCTION:    AcpiDsClearOperands
 443  *
 444  * PARAMETERS:  WalkState           - Current walk state with operands on stack
 445  *
 446  * RETURN:      None
 447  *
 448  * DESCRIPTION: Clear all operands on the current walk state operand stack.
 449  *
 450  ******************************************************************************/
 451
 452 void
 453 AcpiDsClearOperands (
 454     ACPI_WALK_STATE         *WalkState)
 455 {
 456     UINT32                  i;
 457
 458
 459     ACPI_FUNCTION_TRACE_PTR (DsClearOperands, WalkState);
 460
 461
 462     /* Remove a reference on each operand on the stack */
 463
 464     for (i = 0; i < WalkState->NumOperands; i++)
 465     {
 466         /*
 467          * Remove a reference to all operands, including both
 468          * "Arguments" and "Targets".
 469          */
 470         AcpiUtRemoveReference (WalkState->Operands[i]);
 471         WalkState->Operands[i] = NULL;
 472     }
 473
 474     WalkState->NumOperands = 0;
 475     return_VOID;
 476 }
 477
 478
 479 /*******************************************************************************
 480  *
 481  * FUNCTION:    AcpiDsCreateOperand
 482  *
 483  * PARAMETERS:  WalkState       - Current walk state
 484  *              Arg             - Parse object for the argument
 485  *              ArgIndex        - Which argument (zero based)
 486  *
 487  * RETURN:      Status
 488  *
 489  * DESCRIPTION: Translate a parse tree object that is an argument to an AML
 490  *              opcode to the equivalent interpreter object. This may include
 491  *              looking up a name or entering a new name into the internal
 492  *              namespace.
 493  *
 494  ******************************************************************************/
 495
 496 ACPI_STATUS
 497 AcpiDsCreateOperand (
 498     ACPI_WALK_STATE         *WalkState,
 499     ACPI_PARSE_OBJECT       *Arg,
 500     UINT32                  ArgIndex)
 501 {
 502     ACPI_STATUS             Status = AE_OK;
 503     char                    *NameString;
 504     UINT32                  NameLength;
 505     ACPI_OPERAND_OBJECT     *ObjDesc;
 506     ACPI_PARSE_OBJECT       *ParentOp;
 507     UINT16                  Opcode;
 508     ACPI_INTERPRETER_MODE   InterpreterMode;
 509     const ACPI_OPCODE_INFO  *OpInfo;
 510
 511
 512     ACPI_FUNCTION_TRACE_PTR (DsCreateOperand, Arg);
 513
 514
 515     /* A valid name must be looked up in the namespace */
 516
 517     if ((Arg->Common.AmlOpcode == AML_INT_NAMEPATH_OP) &&
 518         (Arg->Common.Value.String) &&
 519         !(Arg->Common.Flags & ACPI_PARSEOP_IN_STACK))
 520     {
 521         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Getting a name: Arg=%p\n", Arg));
 522
 523         /* Get the entire name string from the AML stream */
 524
 525         Status = AcpiExGetNameString (ACPI_TYPE_ANY,
 526             Arg->Common.Value.Buffer, &NameString, &NameLength);
 527
 528         if (ACPI_FAILURE (Status))
 529         {
 530             return_ACPI_STATUS (Status);
 531         }
 532
 533         /* All prefixes have been handled, and the name is in NameString */
 534
 535         /*
 536          * Special handling for BufferField declarations. This is a deferred
 537          * opcode that unfortunately defines the field name as the last
 538          * parameter instead of the first. We get here when we are performing
 539          * the deferred execution, so the actual name of the field is already
 540          * in the namespace. We don't want to attempt to look it up again
 541          * because we may be executing in a different scope than where the
 542          * actual opcode exists.
 543          */
 544         if ((WalkState->DeferredNode) &&
 545             (WalkState->DeferredNode->Type == ACPI_TYPE_BUFFER_FIELD) &&
 546             (ArgIndex == (UINT32)
 547                 ((WalkState->Opcode == AML_CREATE_FIELD_OP) ? 3 : 2)))
 548         {
 549             ObjDesc = ACPI_CAST_PTR (
 550                 ACPI_OPERAND_OBJECT, WalkState->DeferredNode);
 551             Status = AE_OK;
 552         }
 553         else    /* All other opcodes */
 554         {
 555             /*
 556              * Differentiate between a namespace "create" operation
 557              * versus a "lookup" operation (IMODE_LOAD_PASS2 vs.
 558              * IMODE_EXECUTE) in order to support the creation of
 559              * namespace objects during the execution of control methods.
 560              */
 561             ParentOp = Arg->Common.Parent;
 562             OpInfo = AcpiPsGetOpcodeInfo (ParentOp->Common.AmlOpcode);
 563
 564             if ((OpInfo->Flags & AML_NSNODE) &&
 565                 (ParentOp->Common.AmlOpcode != AML_INT_METHODCALL_OP) &&
 566                 (ParentOp->Common.AmlOpcode != AML_REGION_OP) &&
 567                 (ParentOp->Common.AmlOpcode != AML_INT_NAMEPATH_OP))
 568             {
 569                 /* Enter name into namespace if not found */
 570
 571                 InterpreterMode = ACPI_IMODE_LOAD_PASS2;
 572             }
 573             else
 574             {
 575                 /* Return a failure if name not found */
 576
 577                 InterpreterMode = ACPI_IMODE_EXECUTE;
 578             }
 579
 580             Status = AcpiNsLookup (WalkState->ScopeInfo, NameString,
 581                 ACPI_TYPE_ANY, InterpreterMode,
 582                 ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE, WalkState,
 583                 ACPI_CAST_INDIRECT_PTR (ACPI_NAMESPACE_NODE, &ObjDesc));
 584             /*
 585              * The only case where we pass through (ignore) a NOT_FOUND
 586              * error is for the CondRefOf opcode.
 587              */
 588             if (Status == AE_NOT_FOUND)
 589             {
 590                 if (ParentOp->Common.AmlOpcode == AML_CONDITIONAL_REF_OF_OP)
 591                 {
 592                     /*
 593                      * For the Conditional Reference op, it's OK if
 594                      * the name is not found;  We just need a way to
 595                      * indicate this to the interpreter, set the
 596                      * object to the root
 597                      */
 598                     ObjDesc = ACPI_CAST_PTR (
 599                         ACPI_OPERAND_OBJECT, AcpiGbl_RootNode);
 600                     Status = AE_OK;
 601                 }
 602                 else if (ParentOp->Common.AmlOpcode == AML_EXTERNAL_OP)
 603                 {
 604                     /*
 605                      * This opcode should never appear here. It is used only
 606                      * by AML disassemblers and is surrounded by an If(0)
 607                      * by the ASL compiler.
 608                      *
 609                      * Therefore, if we see it here, it is a serious error.
 610                      */
 611                     Status = AE_AML_BAD_OPCODE;
 612                 }
 613                 else
 614                 {
 615                     /*
 616                      * We just plain didn't find it -- which is a
 617                      * very serious error at this point
 618                      */
 619                     Status = AE_AML_NAME_NOT_FOUND;
 620                 }
 621             }
 622
 623             if (ACPI_FAILURE (Status))
 624             {
 625                 ACPI_ERROR_NAMESPACE (WalkState->ScopeInfo,
 626                     NameString, Status);
 627             }
 628         }
 629
 630         /* Free the namestring created above */
 631
 632         ACPI_FREE (NameString);
 633
 634         /* Check status from the lookup */
 635
 636         if (ACPI_FAILURE (Status))
 637         {
 638             return_ACPI_STATUS (Status);
 639         }
 640
 641         /* Put the resulting object onto the current object stack */
 642
 643         Status = AcpiDsObjStackPush (ObjDesc, WalkState);
 644         if (ACPI_FAILURE (Status))
 645         {
 646             return_ACPI_STATUS (Status);
 647         }
 648
 649         AcpiDbDisplayArgumentObject (ObjDesc, WalkState);
 650     }
 651     else
 652     {
 653         /* Check for null name case */
 654
 655         if ((Arg->Common.AmlOpcode == AML_INT_NAMEPATH_OP) &&
 656             !(Arg->Common.Flags & ACPI_PARSEOP_IN_STACK))
 657         {
 658             /*
 659              * If the name is null, this means that this is an
 660              * optional result parameter that was not specified
 661              * in the original ASL. Create a Zero Constant for a
 662              * placeholder. (Store to a constant is a Noop.)
 663              */
 664             Opcode = AML_ZERO_OP;       /* Has no arguments! */
 665
 666             ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 667                 "Null namepath: Arg=%p\n", Arg));
 668         }
 669         else
 670         {
 671             Opcode = Arg->Common.AmlOpcode;
 672         }
 673
 674         /* Get the object type of the argument */
 675
 676         OpInfo = AcpiPsGetOpcodeInfo (Opcode);
 677         if (OpInfo->ObjectType == ACPI_TYPE_INVALID)
 678         {
 679             return_ACPI_STATUS (AE_NOT_IMPLEMENTED);
 680         }
 681
 682         if ((OpInfo->Flags & AML_HAS_RETVAL) ||
 683             (Arg->Common.Flags & ACPI_PARSEOP_IN_STACK))
 684         {
 685             /*
 686              * Use value that was already previously returned
 687              * by the evaluation of this argument
 688              */
 689             Status = AcpiDsResultPop (&ObjDesc, WalkState);
 690             if (ACPI_FAILURE (Status))
 691             {
 692                 /*
 693                  * Only error is underflow, and this indicates
 694                  * a missing or null operand!
 695                  */
 696                 ACPI_EXCEPTION ((AE_INFO, Status,
 697                     "Missing or null operand"));
 698                 return_ACPI_STATUS (Status);
 699             }
 700         }
 701         else
 702         {
 703             /* Create an ACPI_INTERNAL_OBJECT for the argument */
 704
 705             ObjDesc = AcpiUtCreateInternalObject (OpInfo->ObjectType);
 706             if (!ObjDesc)
 707             {
 708                 return_ACPI_STATUS (AE_NO_MEMORY);
 709             }
 710
 711             /* Initialize the new object */
 712
 713             Status = AcpiDsInitObjectFromOp (
 714                 WalkState, Arg, Opcode, &ObjDesc);
 715             if (ACPI_FAILURE (Status))
 716             {
 717                 AcpiUtDeleteObjectDesc (ObjDesc);
 718                 return_ACPI_STATUS (Status);
 719             }
 720         }
 721
 722         /* Put the operand object on the object stack */
 723
 724         Status = AcpiDsObjStackPush (ObjDesc, WalkState);
 725         if (ACPI_FAILURE (Status))
 726         {
 727             return_ACPI_STATUS (Status);
 728         }
 729
 730         AcpiDbDisplayArgumentObject (ObjDesc, WalkState);
 731     }
 732
 733     return_ACPI_STATUS (AE_OK);
 734 }
 735
 736
 737 /*******************************************************************************
 738  *
 739  * FUNCTION:    AcpiDsCreateOperands
 740  *
 741  * PARAMETERS:  WalkState           - Current state
 742  *              FirstArg            - First argument of a parser argument tree
 743  *
 744  * RETURN:      Status
 745  *
 746  * DESCRIPTION: Convert an operator's arguments from a parse tree format to
 747  *              namespace objects and place those argument object on the object
 748  *              stack in preparation for evaluation by the interpreter.
 749  *
 750  ******************************************************************************/
 751
 752 ACPI_STATUS
 753 AcpiDsCreateOperands (
 754     ACPI_WALK_STATE         *WalkState,
 755     ACPI_PARSE_OBJECT       *FirstArg)
 756 {
 757     ACPI_STATUS             Status = AE_OK;
 758     ACPI_PARSE_OBJECT       *Arg;
 759     ACPI_PARSE_OBJECT       *Arguments[ACPI_OBJ_NUM_OPERANDS];
 760     UINT32                  ArgCount = 0;
 761     UINT32                  Index = WalkState->NumOperands;
 762     UINT32                  i;
 763
 764
 765     ACPI_FUNCTION_TRACE_PTR (DsCreateOperands, FirstArg);
 766
 767
 768     /* Get all arguments in the list */
 769
 770     Arg = FirstArg;
 771     while (Arg)
 772     {
 773         if (Index >= ACPI_OBJ_NUM_OPERANDS)
 774         {
 775             return_ACPI_STATUS (AE_BAD_DATA);
 776         }
 777
 778         Arguments[Index] = Arg;
 779         WalkState->Operands [Index] = NULL;
 780
 781         /* Move on to next argument, if any */
 782
 783         Arg = Arg->Common.Next;
 784         ArgCount++;
 785         Index++;
 786     }
 787
 788     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 789         "NumOperands %d, ArgCount %d, Index %d\n",
 790         WalkState->NumOperands, ArgCount, Index));
 791
 792     /* Create the interpreter arguments, in reverse order */
 793
 794     Index--;
 795     for (i = 0; i < ArgCount; i++)
 796     {
 797         Arg = Arguments[Index];
 798         WalkState->OperandIndex = (UINT8) Index;
 799
 800         Status = AcpiDsCreateOperand (WalkState, Arg, Index);
 801         if (ACPI_FAILURE (Status))
 802         {
 803             goto Cleanup;
 804         }
 805
 806         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 807             "Created Arg #%u (%p) %u args total\n",
 808             Index, Arg, ArgCount));
 809         Index--;
 810     }
 811
 812     return_ACPI_STATUS (Status);
 813
 814
 815 Cleanup:
 816     /*
 817      * We must undo everything done above; meaning that we must
 818      * pop everything off of the operand stack and delete those
 819      * objects
 820      */
 821     AcpiDsObjStackPopAndDelete (ArgCount, WalkState);
 822
 823     ACPI_EXCEPTION ((AE_INFO, Status, "While creating Arg %u", Index));
 824     return_ACPI_STATUS (Status);
 825 }
 826
 827
 828 /*****************************************************************************
 829  *
 830  * FUNCTION:    AcpiDsEvaluateNamePath
 831  *
 832  * PARAMETERS:  WalkState       - Current state of the parse tree walk,
 833  *                                the opcode of current operation should be
 834  *                                AML_INT_NAMEPATH_OP
 835  *
 836  * RETURN:      Status
 837  *
 838  * DESCRIPTION: Translate the -NamePath- parse tree object to the equivalent
 839  *              interpreter object, convert it to value, if needed, duplicate
 840  *              it, if needed, and push it onto the current result stack.
 841  *
 842  ****************************************************************************/
 843
 844 ACPI_STATUS
 845 AcpiDsEvaluateNamePath (
 846     ACPI_WALK_STATE         *WalkState)
 847 {
 848     ACPI_STATUS             Status = AE_OK;
 849     ACPI_PARSE_OBJECT       *Op = WalkState->Op;
 850     ACPI_OPERAND_OBJECT     **Operand = &WalkState->Operands[0];
 851     ACPI_OPERAND_OBJECT     *NewObjDesc;
 852     UINT8                   Type;
 853
 854
 855     ACPI_FUNCTION_TRACE_PTR (DsEvaluateNamePath, WalkState);
 856
 857
 858     if (!Op->Common.Parent)
 859     {
 860         /* This happens after certain exception processing */
 861
 862         goto Exit;
 863     }
 864
 865     if ((Op->Common.Parent->Common.AmlOpcode == AML_PACKAGE_OP) ||
 866         (Op->Common.Parent->Common.AmlOpcode == AML_VARIABLE_PACKAGE_OP) ||
 867         (Op->Common.Parent->Common.AmlOpcode == AML_REF_OF_OP))
 868     {
 869         /* TBD: Should we specify this feature as a bit of OpInfo->Flags of these opcodes? */
 870
 871         goto Exit;
 872     }
 873
 874     Status = AcpiDsCreateOperand (WalkState, Op, 0);
 875     if (ACPI_FAILURE (Status))
 876     {
 877         goto Exit;
 878     }
 879
 880     if (Op->Common.Flags & ACPI_PARSEOP_TARGET)
 881     {
 882         NewObjDesc = *Operand;
 883         goto PushResult;
 884     }
 885
 886     Type = (*Operand)->Common.Type;
 887
 888     Status = AcpiExResolveToValue (Operand, WalkState);
 889     if (ACPI_FAILURE (Status))
 890     {
 891         goto Exit;
 892     }
 893
 894     if (Type == ACPI_TYPE_INTEGER)
 895     {
 896         /* It was incremented by AcpiExResolveToValue */
 897
 898         AcpiUtRemoveReference (*Operand);
 899
 900         Status = AcpiUtCopyIobjectToIobject (
 901             *Operand, &NewObjDesc, WalkState);
 902         if (ACPI_FAILURE (Status))
 903         {
 904             goto Exit;
 905         }
 906     }
 907     else
 908     {
 909         /*
 910          * The object either was anew created or is
 911          * a Namespace node - don't decrement it.
 912          */
 913         NewObjDesc = *Operand;
 914     }
 915
 916     /* Cleanup for name-path operand */
 917
 918     Status = AcpiDsObjStackPop (1, WalkState);
 919     if (ACPI_FAILURE (Status))
 920     {
 921         WalkState->ResultObj = NewObjDesc;
 922         goto Exit;
 923     }
 924
 925 PushResult:
 926
 927     WalkState->ResultObj = NewObjDesc;
 928
 929     Status = AcpiDsResultPush (WalkState->ResultObj, WalkState);
 930     if (ACPI_SUCCESS (Status))
 931     {
 932         /* Force to take it from stack */
 933
 934         Op->Common.Flags |= ACPI_PARSEOP_IN_STACK;
 935     }
 936
 937 Exit:
 938
 939     return_ACPI_STATUS (Status);
 940 }