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

   1 /*******************************************************************************
   2  *
   3  * Module Name: dsutils - Dispatcher utilities
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2017, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include "acpi.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 #ifndef ACPI_NO_METHOD_EXECUTION
 105 /*******************************************************************************
 106  *
 107  * FUNCTION:    AcpiDsDoImplicitReturn
 108  *
 109  * PARAMETERS:  ReturnDesc          - The return value
 110  *              WalkState           - Current State
 111  *              AddReference        - True if a reference should be added to the
 112  *                                    return object
 113  *
 114  * RETURN:      TRUE if implicit return enabled, FALSE otherwise
 115  *
 116  * DESCRIPTION: Implements the optional "implicit return".  We save the result
 117  *              of every ASL operator and control method invocation in case the
 118  *              parent method exit. Before storing a new return value, we
 119  *              delete the previous return value.
 120  *
 121  ******************************************************************************/
 122
 123 BOOLEAN
 124 AcpiDsDoImplicitReturn (
 125     ACPI_OPERAND_OBJECT     *ReturnDesc,
 126     ACPI_WALK_STATE         *WalkState,
 127     BOOLEAN                 AddReference)
 128 {
 129     ACPI_FUNCTION_NAME (DsDoImplicitReturn);
 130
 131
 132     /*
 133      * Slack must be enabled for this feature, and we must
 134      * have a valid return object
 135      */
 136     if ((!AcpiGbl_EnableInterpreterSlack) ||
 137         (!ReturnDesc))
 138     {
 139         return (FALSE);
 140     }
 141
 142     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 143         "Result %p will be implicitly returned; Prev=%p\n",
 144         ReturnDesc,
 145         WalkState->ImplicitReturnObj));
 146
 147     /*
 148      * Delete any "stale" implicit return value first. However, in
 149      * complex statements, the implicit return value can be
 150      * bubbled up several levels, so we don't clear the value if it
 151      * is the same as the ReturnDesc.
 152      */
 153     if (WalkState->ImplicitReturnObj)
 154     {
 155         if (WalkState->ImplicitReturnObj == ReturnDesc)
 156         {
 157             return (TRUE);
 158         }
 159         AcpiDsClearImplicitReturn (WalkState);
 160     }
 161
 162     /* Save the implicit return value, add a reference if requested */
 163
 164     WalkState->ImplicitReturnObj = ReturnDesc;
 165     if (AddReference)
 166     {
 167         AcpiUtAddReference (ReturnDesc);
 168     }
 169
 170     return (TRUE);
 171 }
 172
 173
 174 /*******************************************************************************
 175  *
 176  * FUNCTION:    AcpiDsIsResultUsed
 177  *
 178  * PARAMETERS:  Op                  - Current Op
 179  *              WalkState           - Current State
 180  *
 181  * RETURN:      TRUE if result is used, FALSE otherwise
 182  *
 183  * DESCRIPTION: Check if a result object will be used by the parent
 184  *
 185  ******************************************************************************/
 186
 187 BOOLEAN
 188 AcpiDsIsResultUsed (
 189     ACPI_PARSE_OBJECT       *Op,
 190     ACPI_WALK_STATE         *WalkState)
 191 {
 192     const ACPI_OPCODE_INFO  *ParentInfo;
 193
 194     ACPI_FUNCTION_TRACE_PTR (DsIsResultUsed, Op);
 195
 196
 197     /* Must have both an Op and a Result Object */
 198
 199     if (!Op)
 200     {
 201         ACPI_ERROR ((AE_INFO, "Null Op"));
 202         return_UINT8 (TRUE);
 203     }
 204
 205     /*
 206      * We know that this operator is not a
 207      * Return() operator (would not come here.) The following code is the
 208      * optional support for a so-called "implicit return". Some AML code
 209      * assumes that the last value of the method is "implicitly" returned
 210      * to the caller. Just save the last result as the return value.
 211      * NOTE: this is optional because the ASL language does not actually
 212      * support this behavior.
 213      */
 214     (void) AcpiDsDoImplicitReturn (WalkState->ResultObj, WalkState, TRUE);
 215
 216     /*
 217      * Now determine if the parent will use the result
 218      *
 219      * If there is no parent, or the parent is a ScopeOp, we are executing
 220      * at the method level. An executing method typically has no parent,
 221      * since each method is parsed separately. A method invoked externally
 222      * via ExecuteControlMethod has a ScopeOp as the parent.
 223      */
 224     if ((!Op->Common.Parent) ||
 225         (Op->Common.Parent->Common.AmlOpcode == AML_SCOPE_OP))
 226     {
 227         /* No parent, the return value cannot possibly be used */
 228
 229         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 230             "At Method level, result of [%s] not used\n",
 231             AcpiPsGetOpcodeName (Op->Common.AmlOpcode)));
 232         return_UINT8 (FALSE);
 233     }
 234
 235     /* Get info on the parent. The RootOp is AML_SCOPE */
 236
 237     ParentInfo = AcpiPsGetOpcodeInfo (Op->Common.Parent->Common.AmlOpcode);
 238     if (ParentInfo->Class == AML_CLASS_UNKNOWN)
 239     {
 240         ACPI_ERROR ((AE_INFO,
 241             "Unknown parent opcode Op=%p", Op));
 242         return_UINT8 (FALSE);
 243     }
 244
 245     /*
 246      * Decide what to do with the result based on the parent. If
 247      * the parent opcode will not use the result, delete the object.
 248      * Otherwise leave it as is, it will be deleted when it is used
 249      * as an operand later.
 250      */
 251     switch (ParentInfo->Class)
 252     {
 253     case AML_CLASS_CONTROL:
 254
 255         switch (Op->Common.Parent->Common.AmlOpcode)
 256         {
 257         case AML_RETURN_OP:
 258
 259             /* Never delete the return value associated with a return opcode */
 260
 261             goto ResultUsed;
 262
 263         case AML_IF_OP:
 264         case AML_WHILE_OP:
 265             /*
 266              * If we are executing the predicate AND this is the predicate op,
 267              * we will use the return value
 268              */
 269             if ((WalkState->ControlState->Common.State ==
 270                     ACPI_CONTROL_PREDICATE_EXECUTING) &&
 271                 (WalkState->ControlState->Control.PredicateOp == Op))
 272             {
 273                 goto ResultUsed;
 274             }
 275             break;
 276
 277         default:
 278
 279             /* Ignore other control opcodes */
 280
 281             break;
 282         }
 283
 284         /* The general control opcode returns no result */
 285
 286         goto ResultNotUsed;
 287
 288     case AML_CLASS_CREATE:
 289         /*
 290          * These opcodes allow TermArg(s) as operands and therefore
 291          * the operands can be method calls. The result is used.
 292          */
 293         goto ResultUsed;
 294
 295     case AML_CLASS_NAMED_OBJECT:
 296
 297         if ((Op->Common.Parent->Common.AmlOpcode == AML_REGION_OP)       ||
 298             (Op->Common.Parent->Common.AmlOpcode == AML_DATA_REGION_OP)  ||
 299             (Op->Common.Parent->Common.AmlOpcode == AML_PACKAGE_OP)      ||
 300             (Op->Common.Parent->Common.AmlOpcode == AML_BUFFER_OP)       ||
 301             (Op->Common.Parent->Common.AmlOpcode == AML_VARIABLE_PACKAGE_OP) ||
 302             (Op->Common.Parent->Common.AmlOpcode == AML_INT_EVAL_SUBTREE_OP) ||
 303             (Op->Common.Parent->Common.AmlOpcode == AML_BANK_FIELD_OP))
 304         {
 305             /*
 306              * These opcodes allow TermArg(s) as operands and therefore
 307              * the operands can be method calls. The result is used.
 308              */
 309             goto ResultUsed;
 310         }
 311
 312         goto ResultNotUsed;
 313
 314     default:
 315         /*
 316          * In all other cases. the parent will actually use the return
 317          * object, so keep it.
 318          */
 319         goto ResultUsed;
 320     }
 321
 322
 323 ResultUsed:
 324     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 325         "Result of [%s] used by Parent [%s] Op=%p\n",
 326         AcpiPsGetOpcodeName (Op->Common.AmlOpcode),
 327         AcpiPsGetOpcodeName (Op->Common.Parent->Common.AmlOpcode), Op));
 328
 329     return_UINT8 (TRUE);
 330
 331
 332 ResultNotUsed:
 333     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 334         "Result of [%s] not used by Parent [%s] Op=%p\n",
 335         AcpiPsGetOpcodeName (Op->Common.AmlOpcode),
 336         AcpiPsGetOpcodeName (Op->Common.Parent->Common.AmlOpcode), Op));
 337
 338     return_UINT8 (FALSE);
 339 }
 340
 341
 342 /*******************************************************************************
 343  *
 344  * FUNCTION:    AcpiDsDeleteResultIfNotUsed
 345  *
 346  * PARAMETERS:  Op              - Current parse Op
 347  *              ResultObj       - Result of the operation
 348  *              WalkState       - Current state
 349  *
 350  * RETURN:      Status
 351  *
 352  * DESCRIPTION: Used after interpretation of an opcode. If there is an internal
 353  *              result descriptor, check if the parent opcode will actually use
 354  *              this result. If not, delete the result now so that it will
 355  *              not become orphaned.
 356  *
 357  ******************************************************************************/
 358
 359 void
 360 AcpiDsDeleteResultIfNotUsed (
 361     ACPI_PARSE_OBJECT       *Op,
 362     ACPI_OPERAND_OBJECT     *ResultObj,
 363     ACPI_WALK_STATE         *WalkState)
 364 {
 365     ACPI_OPERAND_OBJECT     *ObjDesc;
 366     ACPI_STATUS             Status;
 367
 368
 369     ACPI_FUNCTION_TRACE_PTR (DsDeleteResultIfNotUsed, ResultObj);
 370
 371
 372     if (!Op)
 373     {
 374         ACPI_ERROR ((AE_INFO, "Null Op"));
 375         return_VOID;
 376     }
 377
 378     if (!ResultObj)
 379     {
 380         return_VOID;
 381     }
 382
 383     if (!AcpiDsIsResultUsed (Op, WalkState))
 384     {
 385         /* Must pop the result stack (ObjDesc should be equal to ResultObj) */
 386
 387         Status = AcpiDsResultPop (&ObjDesc, WalkState);
 388         if (ACPI_SUCCESS (Status))
 389         {
 390             AcpiUtRemoveReference (ResultObj);
 391         }
 392     }
 393
 394     return_VOID;
 395 }
 396
 397
 398 /*******************************************************************************
 399  *
 400  * FUNCTION:    AcpiDsResolveOperands
 401  *
 402  * PARAMETERS:  WalkState           - Current walk state with operands on stack
 403  *
 404  * RETURN:      Status
 405  *
 406  * DESCRIPTION: Resolve all operands to their values. Used to prepare
 407  *              arguments to a control method invocation (a call from one
 408  *              method to another.)
 409  *
 410  ******************************************************************************/
 411
 412 ACPI_STATUS
 413 AcpiDsResolveOperands (
 414     ACPI_WALK_STATE         *WalkState)
 415 {
 416     UINT32                  i;
 417     ACPI_STATUS             Status = AE_OK;
 418
 419
 420     ACPI_FUNCTION_TRACE_PTR (DsResolveOperands, WalkState);
 421
 422
 423     /*
 424      * Attempt to resolve each of the valid operands
 425      * Method arguments are passed by reference, not by value. This means
 426      * that the actual objects are passed, not copies of the objects.
 427      */
 428     for (i = 0; i < WalkState->NumOperands; i++)
 429     {
 430         Status = AcpiExResolveToValue (&WalkState->Operands[i], WalkState);
 431         if (ACPI_FAILURE (Status))
 432         {
 433             break;
 434         }
 435     }
 436
 437     return_ACPI_STATUS (Status);
 438 }
 439
 440
 441 /*******************************************************************************
 442  *
 443  * FUNCTION:    AcpiDsClearOperands
 444  *
 445  * PARAMETERS:  WalkState           - Current walk state with operands on stack
 446  *
 447  * RETURN:      None
 448  *
 449  * DESCRIPTION: Clear all operands on the current walk state operand stack.
 450  *
 451  ******************************************************************************/
 452
 453 void
 454 AcpiDsClearOperands (
 455     ACPI_WALK_STATE         *WalkState)
 456 {
 457     UINT32                  i;
 458
 459
 460     ACPI_FUNCTION_TRACE_PTR (DsClearOperands, WalkState);
 461
 462
 463     /* Remove a reference on each operand on the stack */
 464
 465     for (i = 0; i < WalkState->NumOperands; i++)
 466     {
 467         /*
 468          * Remove a reference to all operands, including both
 469          * "Arguments" and "Targets".
 470          */
 471         AcpiUtRemoveReference (WalkState->Operands[i]);
 472         WalkState->Operands[i] = NULL;
 473     }
 474
 475     WalkState->NumOperands = 0;
 476     return_VOID;
 477 }
 478 #endif
 479
 480
 481 /*******************************************************************************
 482  *
 483  * FUNCTION:    AcpiDsCreateOperand
 484  *
 485  * PARAMETERS:  WalkState       - Current walk state
 486  *              Arg             - Parse object for the argument
 487  *              ArgIndex        - Which argument (zero based)
 488  *
 489  * RETURN:      Status
 490  *
 491  * DESCRIPTION: Translate a parse tree object that is an argument to an AML
 492  *              opcode to the equivalent interpreter object. This may include
 493  *              looking up a name or entering a new name into the internal
 494  *              namespace.
 495  *
 496  ******************************************************************************/
 497
 498 ACPI_STATUS
 499 AcpiDsCreateOperand (
 500     ACPI_WALK_STATE         *WalkState,
 501     ACPI_PARSE_OBJECT       *Arg,
 502     UINT32                  ArgIndex)
 503 {
 504     ACPI_STATUS             Status = AE_OK;
 505     char                    *NameString;
 506     UINT32                  NameLength;
 507     ACPI_OPERAND_OBJECT     *ObjDesc;
 508     ACPI_PARSE_OBJECT       *ParentOp;
 509     UINT16                  Opcode;
 510     ACPI_INTERPRETER_MODE   InterpreterMode;
 511     const ACPI_OPCODE_INFO  *OpInfo;
 512
 513
 514     ACPI_FUNCTION_TRACE_PTR (DsCreateOperand, Arg);
 515
 516
 517     /* A valid name must be looked up in the namespace */
 518
 519     if ((Arg->Common.AmlOpcode == AML_INT_NAMEPATH_OP) &&
 520         (Arg->Common.Value.String) &&
 521         !(Arg->Common.Flags & ACPI_PARSEOP_IN_STACK))
 522     {
 523         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Getting a name: Arg=%p\n", Arg));
 524
 525         /* Get the entire name string from the AML stream */
 526
 527         Status = AcpiExGetNameString (ACPI_TYPE_ANY,
 528             Arg->Common.Value.Buffer, &NameString, &NameLength);
 529
 530         if (ACPI_FAILURE (Status))
 531         {
 532             return_ACPI_STATUS (Status);
 533         }
 534
 535         /* All prefixes have been handled, and the name is in NameString */
 536
 537         /*
 538          * Special handling for BufferField declarations. This is a deferred
 539          * opcode that unfortunately defines the field name as the last
 540          * parameter instead of the first. We get here when we are performing
 541          * the deferred execution, so the actual name of the field is already
 542          * in the namespace. We don't want to attempt to look it up again
 543          * because we may be executing in a different scope than where the
 544          * actual opcode exists.
 545          */
 546         if ((WalkState->DeferredNode) &&
 547             (WalkState->DeferredNode->Type == ACPI_TYPE_BUFFER_FIELD) &&
 548             (ArgIndex == (UINT32)
 549                 ((WalkState->Opcode == AML_CREATE_FIELD_OP) ? 3 : 2)))
 550         {
 551             ObjDesc = ACPI_CAST_PTR (
 552                 ACPI_OPERAND_OBJECT, WalkState->DeferredNode);
 553             Status = AE_OK;
 554         }
 555         else    /* All other opcodes */
 556         {
 557             /*
 558              * Differentiate between a namespace "create" operation
 559              * versus a "lookup" operation (IMODE_LOAD_PASS2 vs.
 560              * IMODE_EXECUTE) in order to support the creation of
 561              * namespace objects during the execution of control methods.
 562              */
 563             ParentOp = Arg->Common.Parent;
 564             OpInfo = AcpiPsGetOpcodeInfo (ParentOp->Common.AmlOpcode);
 565
 566             if ((OpInfo->Flags & AML_NSNODE) &&
 567                 (ParentOp->Common.AmlOpcode != AML_INT_METHODCALL_OP) &&
 568                 (ParentOp->Common.AmlOpcode != AML_REGION_OP) &&
 569                 (ParentOp->Common.AmlOpcode != AML_INT_NAMEPATH_OP))
 570             {
 571                 /* Enter name into namespace if not found */
 572
 573                 InterpreterMode = ACPI_IMODE_LOAD_PASS2;
 574             }
 575             else
 576             {
 577                 /* Return a failure if name not found */
 578
 579                 InterpreterMode = ACPI_IMODE_EXECUTE;
 580             }
 581
 582             Status = AcpiNsLookup (WalkState->ScopeInfo, NameString,
 583                 ACPI_TYPE_ANY, InterpreterMode,
 584                 ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE, WalkState,
 585                 ACPI_CAST_INDIRECT_PTR (ACPI_NAMESPACE_NODE, &ObjDesc));
 586             /*
 587              * The only case where we pass through (ignore) a NOT_FOUND
 588              * error is for the CondRefOf opcode.
 589              */
 590             if (Status == AE_NOT_FOUND)
 591             {
 592                 if (ParentOp->Common.AmlOpcode == AML_CONDITIONAL_REF_OF_OP)
 593                 {
 594                     /*
 595                      * For the Conditional Reference op, it's OK if
 596                      * the name is not found;  We just need a way to
 597                      * indicate this to the interpreter, set the
 598                      * object to the root
 599                      */
 600                     ObjDesc = ACPI_CAST_PTR (
 601                         ACPI_OPERAND_OBJECT, AcpiGbl_RootNode);
 602                     Status = AE_OK;
 603                 }
 604                 else if (ParentOp->Common.AmlOpcode == AML_EXTERNAL_OP)
 605                 {
 606                     /*
 607                      * This opcode should never appear here. It is used only
 608                      * by AML disassemblers and is surrounded by an If(0)
 609                      * by the ASL compiler.
 610                      *
 611                      * Therefore, if we see it here, it is a serious error.
 612                      */
 613                     Status = AE_AML_BAD_OPCODE;
 614                 }
 615                 else
 616                 {
 617                     /*
 618                      * We just plain didn't find it -- which is a
 619                      * very serious error at this point
 620                      */
 621                     Status = AE_AML_NAME_NOT_FOUND;
 622                 }
 623             }
 624
 625             if (ACPI_FAILURE (Status))
 626             {
 627                 ACPI_ERROR_NAMESPACE (WalkState->ScopeInfo,
 628                     NameString, Status);
 629             }
 630         }
 631
 632         /* Free the namestring created above */
 633
 634         ACPI_FREE (NameString);
 635
 636         /* Check status from the lookup */
 637
 638         if (ACPI_FAILURE (Status))
 639         {
 640             return_ACPI_STATUS (Status);
 641         }
 642
 643         /* Put the resulting object onto the current object stack */
 644
 645         Status = AcpiDsObjStackPush (ObjDesc, WalkState);
 646         if (ACPI_FAILURE (Status))
 647         {
 648             return_ACPI_STATUS (Status);
 649         }
 650
 651         AcpiDbDisplayArgumentObject (ObjDesc, WalkState);
 652     }
 653     else
 654     {
 655         /* Check for null name case */
 656
 657         if ((Arg->Common.AmlOpcode == AML_INT_NAMEPATH_OP) &&
 658             !(Arg->Common.Flags & ACPI_PARSEOP_IN_STACK))
 659         {
 660             /*
 661              * If the name is null, this means that this is an
 662              * optional result parameter that was not specified
 663              * in the original ASL. Create a Zero Constant for a
 664              * placeholder. (Store to a constant is a Noop.)
 665              */
 666             Opcode = AML_ZERO_OP;       /* Has no arguments! */
 667
 668             ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 669                 "Null namepath: Arg=%p\n", Arg));
 670         }
 671         else
 672         {
 673             Opcode = Arg->Common.AmlOpcode;
 674         }
 675
 676         /* Get the object type of the argument */
 677
 678         OpInfo = AcpiPsGetOpcodeInfo (Opcode);
 679         if (OpInfo->ObjectType == ACPI_TYPE_INVALID)
 680         {
 681             return_ACPI_STATUS (AE_NOT_IMPLEMENTED);
 682         }
 683
 684         if ((OpInfo->Flags & AML_HAS_RETVAL) ||
 685             (Arg->Common.Flags & ACPI_PARSEOP_IN_STACK))
 686         {
 687             /*
 688              * Use value that was already previously returned
 689              * by the evaluation of this argument
 690              */
 691             Status = AcpiDsResultPop (&ObjDesc, WalkState);
 692             if (ACPI_FAILURE (Status))
 693             {
 694                 /*
 695                  * Only error is underflow, and this indicates
 696                  * a missing or null operand!
 697                  */
 698                 ACPI_EXCEPTION ((AE_INFO, Status,
 699                     "Missing or null operand"));
 700                 return_ACPI_STATUS (Status);
 701             }
 702         }
 703         else
 704         {
 705             /* Create an ACPI_INTERNAL_OBJECT for the argument */
 706
 707             ObjDesc = AcpiUtCreateInternalObject (OpInfo->ObjectType);
 708             if (!ObjDesc)
 709             {
 710                 return_ACPI_STATUS (AE_NO_MEMORY);
 711             }
 712
 713             /* Initialize the new object */
 714
 715             Status = AcpiDsInitObjectFromOp (
 716                 WalkState, Arg, Opcode, &ObjDesc);
 717             if (ACPI_FAILURE (Status))
 718             {
 719                 AcpiUtDeleteObjectDesc (ObjDesc);
 720                 return_ACPI_STATUS (Status);
 721             }
 722         }
 723
 724         /* Put the operand object on the object stack */
 725
 726         Status = AcpiDsObjStackPush (ObjDesc, WalkState);
 727         if (ACPI_FAILURE (Status))
 728         {
 729             return_ACPI_STATUS (Status);
 730         }
 731
 732         AcpiDbDisplayArgumentObject (ObjDesc, WalkState);
 733     }
 734
 735     return_ACPI_STATUS (AE_OK);
 736 }
 737
 738
 739 /*******************************************************************************
 740  *
 741  * FUNCTION:    AcpiDsCreateOperands
 742  *
 743  * PARAMETERS:  WalkState           - Current state
 744  *              FirstArg            - First argument of a parser argument tree
 745  *
 746  * RETURN:      Status
 747  *
 748  * DESCRIPTION: Convert an operator's arguments from a parse tree format to
 749  *              namespace objects and place those argument object on the object
 750  *              stack in preparation for evaluation by the interpreter.
 751  *
 752  ******************************************************************************/
 753
 754 ACPI_STATUS
 755 AcpiDsCreateOperands (
 756     ACPI_WALK_STATE         *WalkState,
 757     ACPI_PARSE_OBJECT       *FirstArg)
 758 {
 759     ACPI_STATUS             Status = AE_OK;
 760     ACPI_PARSE_OBJECT       *Arg;
 761     ACPI_PARSE_OBJECT       *Arguments[ACPI_OBJ_NUM_OPERANDS];
 762     UINT32                  ArgCount = 0;
 763     UINT32                  Index = WalkState->NumOperands;
 764     UINT32                  i;
 765
 766
 767     ACPI_FUNCTION_TRACE_PTR (DsCreateOperands, FirstArg);
 768
 769
 770     /* Get all arguments in the list */
 771
 772     Arg = FirstArg;
 773     while (Arg)
 774     {
 775         if (Index >= ACPI_OBJ_NUM_OPERANDS)
 776         {
 777             return_ACPI_STATUS (AE_BAD_DATA);
 778         }
 779
 780         Arguments[Index] = Arg;
 781         WalkState->Operands [Index] = NULL;
 782
 783         /* Move on to next argument, if any */
 784
 785         Arg = Arg->Common.Next;
 786         ArgCount++;
 787         Index++;
 788     }
 789
 790     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 791         "NumOperands %d, ArgCount %d, Index %d\n",
 792         WalkState->NumOperands, ArgCount, Index));
 793
 794     /* Create the interpreter arguments, in reverse order */
 795
 796     Index--;
 797     for (i = 0; i < ArgCount; i++)
 798     {
 799         Arg = Arguments[Index];
 800         WalkState->OperandIndex = (UINT8) Index;
 801
 802         Status = AcpiDsCreateOperand (WalkState, Arg, Index);
 803         if (ACPI_FAILURE (Status))
 804         {
 805             goto Cleanup;
 806         }
 807
 808         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
 809             "Created Arg #%u (%p) %u args total\n",
 810             Index, Arg, ArgCount));
 811         Index--;
 812     }
 813
 814     return_ACPI_STATUS (Status);
 815
 816
 817 Cleanup:
 818     /*
 819      * We must undo everything done above; meaning that we must
 820      * pop everything off of the operand stack and delete those
 821      * objects
 822      */
 823     AcpiDsObjStackPopAndDelete (ArgCount, WalkState);
 824
 825     ACPI_EXCEPTION ((AE_INFO, Status, "While creating Arg %u", Index));
 826     return_ACPI_STATUS (Status);
 827 }
 828
 829
 830 /*****************************************************************************
 831  *
 832  * FUNCTION:    AcpiDsEvaluateNamePath
 833  *
 834  * PARAMETERS:  WalkState       - Current state of the parse tree walk,
 835  *                                the opcode of current operation should be
 836  *                                AML_INT_NAMEPATH_OP
 837  *
 838  * RETURN:      Status
 839  *
 840  * DESCRIPTION: Translate the -NamePath- parse tree object to the equivalent
 841  *              interpreter object, convert it to value, if needed, duplicate
 842  *              it, if needed, and push it onto the current result stack.
 843  *
 844  ****************************************************************************/
 845
 846 ACPI_STATUS
 847 AcpiDsEvaluateNamePath (
 848     ACPI_WALK_STATE         *WalkState)
 849 {
 850     ACPI_STATUS             Status = AE_OK;
 851     ACPI_PARSE_OBJECT       *Op = WalkState->Op;
 852     ACPI_OPERAND_OBJECT     **Operand = &WalkState->Operands[0];
 853     ACPI_OPERAND_OBJECT     *NewObjDesc;
 854     UINT8                   Type;
 855
 856
 857     ACPI_FUNCTION_TRACE_PTR (DsEvaluateNamePath, WalkState);
 858
 859
 860     if (!Op->Common.Parent)
 861     {
 862         /* This happens after certain exception processing */
 863
 864         goto Exit;
 865     }
 866
 867     if ((Op->Common.Parent->Common.AmlOpcode == AML_PACKAGE_OP) ||
 868         (Op->Common.Parent->Common.AmlOpcode == AML_VARIABLE_PACKAGE_OP) ||
 869         (Op->Common.Parent->Common.AmlOpcode == AML_REF_OF_OP))
 870     {
 871         /* TBD: Should we specify this feature as a bit of OpInfo->Flags of these opcodes? */
 872
 873         goto Exit;
 874     }
 875
 876     Status = AcpiDsCreateOperand (WalkState, Op, 0);
 877     if (ACPI_FAILURE (Status))
 878     {
 879         goto Exit;
 880     }
 881
 882     if (Op->Common.Flags & ACPI_PARSEOP_TARGET)
 883     {
 884         NewObjDesc = *Operand;
 885         goto PushResult;
 886     }
 887
 888     Type = (*Operand)->Common.Type;
 889
 890     Status = AcpiExResolveToValue (Operand, WalkState);
 891     if (ACPI_FAILURE (Status))
 892     {
 893         goto Exit;
 894     }
 895
 896     if (Type == ACPI_TYPE_INTEGER)
 897     {
 898         /* It was incremented by AcpiExResolveToValue */
 899
 900         AcpiUtRemoveReference (*Operand);
 901
 902         Status = AcpiUtCopyIobjectToIobject (
 903             *Operand, &NewObjDesc, WalkState);
 904         if (ACPI_FAILURE (Status))
 905         {
 906             goto Exit;
 907         }
 908     }
 909     else
 910     {
 911         /*
 912          * The object either was anew created or is
 913          * a Namespace node - don't decrement it.
 914          */
 915         NewObjDesc = *Operand;
 916     }
 917
 918     /* Cleanup for name-path operand */
 919
 920     Status = AcpiDsObjStackPop (1, WalkState);
 921     if (ACPI_FAILURE (Status))
 922     {
 923         WalkState->ResultObj = NewObjDesc;
 924         goto Exit;
 925     }
 926
 927 PushResult:
 928
 929     WalkState->ResultObj = NewObjDesc;
 930
 931     Status = AcpiDsResultPush (WalkState->ResultObj, WalkState);
 932     if (ACPI_SUCCESS (Status))
 933     {
 934         /* Force to take it from stack */
 935
 936         Op->Common.Flags |= ACPI_PARSEOP_IN_STACK;
 937     }
 938
 939 Exit:
 940
 941     return_ACPI_STATUS (Status);
 942 }