drivers/acpi/parser/psargs.c

   1 /******************************************************************************
   2  *
   3  * Module Name: psargs - Parse AML opcode arguments
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2006, 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/acnamesp.h>
  48 #include <acpi/acdispat.h>
  49
  50 #define _COMPONENT          ACPI_PARSER
  51 ACPI_MODULE_NAME("psargs")
  52
  53 /* Local prototypes */
  54 static u32
  55 acpi_ps_get_next_package_length(struct acpi_parse_state *parser_state);
  56
  57 static union acpi_parse_object *acpi_ps_get_next_field(struct acpi_parse_state
  58                                                        *parser_state);
  59
  60 /*******************************************************************************
  61  *
  62  * FUNCTION:    acpi_ps_get_next_package_length
  63  *
  64  * PARAMETERS:  parser_state        - Current parser state object
  65  *
  66  * RETURN:      Decoded package length. On completion, the AML pointer points
  67  *              past the length byte or bytes.
  68  *
  69  * DESCRIPTION: Decode and return a package length field.
  70  *              Note: Largest package length is 28 bits, from ACPI specification
  71  *
  72  ******************************************************************************/
  73
  74 static u32
  75 acpi_ps_get_next_package_length(struct acpi_parse_state *parser_state)
  76 {
  77         u8 *aml = parser_state->aml;
  78         u32 package_length = 0;
  79         acpi_native_uint byte_count;
  80         u8 byte_zero_mask = 0x3F;       /* Default [0:5] */
  81
  82         ACPI_FUNCTION_TRACE("ps_get_next_package_length");
  83
  84         /*
  85          * Byte 0 bits [6:7] contain the number of additional bytes
  86          * used to encode the package length, either 0,1,2, or 3
  87          */
  88         byte_count = (aml[0] >> 6);
  89         parser_state->aml += (byte_count + 1);
  90
  91         /* Get bytes 3, 2, 1 as needed */
  92
  93         while (byte_count) {
  94                 /*
  95                  * Final bit positions for the package length bytes:
  96                  *      Byte3->[20:27]
  97                  *      Byte2->[12:19]
  98                  *      Byte1->[04:11]
  99                  *      Byte0->[00:03]
 100                  */
 101                 package_length |= (aml[byte_count] << ((byte_count << 3) - 4));
 102
 103                 byte_zero_mask = 0x0F;  /* Use bits [0:3] of byte 0 */
 104                 byte_count--;
 105         }
 106
 107         /* Byte 0 is a special case, either bits [0:3] or [0:5] are used */
 108
 109         package_length |= (aml[0] & byte_zero_mask);
 110         return_UINT32(package_length);
 111 }
 112
 113 /*******************************************************************************
 114  *
 115  * FUNCTION:    acpi_ps_get_next_package_end
 116  *
 117  * PARAMETERS:  parser_state        - Current parser state object
 118  *
 119  * RETURN:      Pointer to end-of-package +1
 120  *
 121  * DESCRIPTION: Get next package length and return a pointer past the end of
 122  *              the package.  Consumes the package length field
 123  *
 124  ******************************************************************************/
 125
 126 u8 *acpi_ps_get_next_package_end(struct acpi_parse_state *parser_state)
 127 {
 128         u8 *start = parser_state->aml;
 129         u32 package_length;
 130
 131         ACPI_FUNCTION_TRACE("ps_get_next_package_end");
 132
 133         /* Function below updates parser_state->Aml */
 134
 135         package_length = acpi_ps_get_next_package_length(parser_state);
 136
 137         return_PTR(start + package_length);     /* end of package */
 138 }
 139
 140 /*******************************************************************************
 141  *
 142  * FUNCTION:    acpi_ps_get_next_namestring
 143  *
 144  * PARAMETERS:  parser_state        - Current parser state object
 145  *
 146  * RETURN:      Pointer to the start of the name string (pointer points into
 147  *              the AML.
 148  *
 149  * DESCRIPTION: Get next raw namestring within the AML stream.  Handles all name
 150  *              prefix characters.  Set parser state to point past the string.
 151  *              (Name is consumed from the AML.)
 152  *
 153  ******************************************************************************/
 154
 155 char *acpi_ps_get_next_namestring(struct acpi_parse_state *parser_state)
 156 {
 157         u8 *start = parser_state->aml;
 158         u8 *end = parser_state->aml;
 159
 160         ACPI_FUNCTION_TRACE("ps_get_next_namestring");
 161
 162         /* Point past any namestring prefix characters (backslash or carat) */
 163
 164         while (acpi_ps_is_prefix_char(*end)) {
 165                 end++;
 166         }
 167
 168         /* Decode the path prefix character */
 169
 170         switch (*end) {
 171         case 0:
 172
 173                 /* null_name */
 174
 175                 if (end == start) {
 176                         start = NULL;
 177                 }
 178                 end++;
 179                 break;
 180
 181         case AML_DUAL_NAME_PREFIX:
 182
 183                 /* Two name segments */
 184
 185                 end += 1 + (2 * ACPI_NAME_SIZE);
 186                 break;
 187
 188         case AML_MULTI_NAME_PREFIX_OP:
 189
 190                 /* Multiple name segments, 4 chars each, count in next byte */
 191
 192                 end += 2 + (*(end + 1) * ACPI_NAME_SIZE);
 193                 break;
 194
 195         default:
 196
 197                 /* Single name segment */
 198
 199                 end += ACPI_NAME_SIZE;
 200                 break;
 201         }
 202
 203         parser_state->aml = end;
 204         return_PTR((char *)start);
 205 }
 206
 207 /*******************************************************************************
 208  *
 209  * FUNCTION:    acpi_ps_get_next_namepath
 210  *
 211  * PARAMETERS:  parser_state        - Current parser state object
 212  *              Arg                 - Where the namepath will be stored
 213  *              arg_count           - If the namepath points to a control method
 214  *                                    the method's argument is returned here.
 215  *              possible_method_call - Whether the namepath can possibly be the
 216  *                                    start of a method call
 217  *
 218  * RETURN:      Status
 219  *
 220  * DESCRIPTION: Get next name (if method call, return # of required args).
 221  *              Names are looked up in the internal namespace to determine
 222  *              if the name represents a control method.  If a method
 223  *              is found, the number of arguments to the method is returned.
 224  *              This information is critical for parsing to continue correctly.
 225  *
 226  ******************************************************************************/
 227
 228 acpi_status
 229 acpi_ps_get_next_namepath(struct acpi_walk_state *walk_state,
 230                           struct acpi_parse_state *parser_state,
 231                           union acpi_parse_object *arg, u8 possible_method_call)
 232 {
 233         char *path;
 234         union acpi_parse_object *name_op;
 235         acpi_status status;
 236         union acpi_operand_object *method_desc;
 237         struct acpi_namespace_node *node;
 238         union acpi_generic_state scope_info;
 239
 240         ACPI_FUNCTION_TRACE("ps_get_next_namepath");
 241
 242         path = acpi_ps_get_next_namestring(parser_state);
 243         acpi_ps_init_op(arg, AML_INT_NAMEPATH_OP);
 244
 245         /* Null path case is allowed, just exit */
 246
 247         if (!path) {
 248                 arg->common.value.name = path;
 249                 return_ACPI_STATUS(AE_OK);
 250         }
 251
 252         /* Setup search scope info */
 253
 254         scope_info.scope.node = NULL;
 255         node = parser_state->start_node;
 256         if (node) {
 257                 scope_info.scope.node = node;
 258         }
 259
 260         /*
 261          * Lookup the name in the internal namespace. We don't want to add
 262          * anything new to the namespace here, however, so we use MODE_EXECUTE.
 263          * Allow searching of the parent tree, but don't open a new scope -
 264          * we just want to lookup the object (must be mode EXECUTE to perform
 265          * the upsearch)
 266          */
 267         status =
 268             acpi_ns_lookup(&scope_info, path, ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
 269                            ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE,
 270                            NULL, &node);
 271
 272         /*
 273          * If this name is a control method invocation, we must
 274          * setup the method call
 275          */
 276         if (ACPI_SUCCESS(status) &&
 277             possible_method_call && (node->type == ACPI_TYPE_METHOD)) {
 278                 /* This name is actually a control method invocation */
 279
 280                 method_desc = acpi_ns_get_attached_object(node);
 281                 ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 282                                   "Control Method - %p Desc %p Path=%p\n", node,
 283                                   method_desc, path));
 284
 285                 name_op = acpi_ps_alloc_op(AML_INT_NAMEPATH_OP);
 286                 if (!name_op) {
 287                         return_ACPI_STATUS(AE_NO_MEMORY);
 288                 }
 289
 290                 /* Change Arg into a METHOD CALL and attach name to it */
 291
 292                 acpi_ps_init_op(arg, AML_INT_METHODCALL_OP);
 293                 name_op->common.value.name = path;
 294
 295                 /* Point METHODCALL/NAME to the METHOD Node */
 296
 297                 name_op->common.node = node;
 298                 acpi_ps_append_arg(arg, name_op);
 299
 300                 if (!method_desc) {
 301                         ACPI_REPORT_ERROR(("Control Method %p has no attached object\n", node));
 302                         return_ACPI_STATUS(AE_AML_INTERNAL);
 303                 }
 304
 305                 ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 306                                   "Control Method - %p Args %X\n",
 307                                   node, method_desc->method.param_count));
 308
 309                 /* Get the number of arguments to expect */
 310
 311                 walk_state->arg_count = method_desc->method.param_count;
 312                 return_ACPI_STATUS(AE_OK);
 313         }
 314
 315         /*
 316          * Special handling if the name was not found during the lookup -
 317          * some not_found cases are allowed
 318          */
 319         if (status == AE_NOT_FOUND) {
 320                 /* 1) not_found is ok during load pass 1/2 (allow forward references) */
 321
 322                 if ((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) !=
 323                     ACPI_PARSE_EXECUTE) {
 324                         status = AE_OK;
 325                 }
 326
 327                 /* 2) not_found during a cond_ref_of(x) is ok by definition */
 328
 329                 else if (walk_state->op->common.aml_opcode ==
 330                          AML_COND_REF_OF_OP) {
 331                         status = AE_OK;
 332                 }
 333
 334                 /*
 335                  * 3) not_found while building a Package is ok at this point, we
 336                  * may flag as an error later if slack mode is not enabled.
 337                  * (Some ASL code depends on allowing this behavior)
 338                  */
 339                 else if ((arg->common.parent) &&
 340                          ((arg->common.parent->common.aml_opcode ==
 341                            AML_PACKAGE_OP)
 342                           || (arg->common.parent->common.aml_opcode ==
 343                               AML_VAR_PACKAGE_OP))) {
 344                         status = AE_OK;
 345                 }
 346         }
 347
 348         /* Final exception check (may have been changed from code above) */
 349
 350         if (ACPI_FAILURE(status)) {
 351                 ACPI_REPORT_NSERROR(path, status);
 352
 353                 if ((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) ==
 354                     ACPI_PARSE_EXECUTE) {
 355                         /* Report a control method execution error */
 356
 357                         status = acpi_ds_method_error(status, walk_state);
 358                 }
 359         }
 360
 361         /* Save the namepath */
 362
 363         arg->common.value.name = path;
 364         return_ACPI_STATUS(status);
 365 }
 366
 367 /*******************************************************************************
 368  *
 369  * FUNCTION:    acpi_ps_get_next_simple_arg
 370  *
 371  * PARAMETERS:  parser_state        - Current parser state object
 372  *              arg_type            - The argument type (AML_*_ARG)
 373  *              Arg                 - Where the argument is returned
 374  *
 375  * RETURN:      None
 376  *
 377  * DESCRIPTION: Get the next simple argument (constant, string, or namestring)
 378  *
 379  ******************************************************************************/
 380
 381 void
 382 acpi_ps_get_next_simple_arg(struct acpi_parse_state *parser_state,
 383                             u32 arg_type, union acpi_parse_object *arg)
 384 {
 385         u32 length;
 386         u16 opcode;
 387         u8 *aml = parser_state->aml;
 388
 389         ACPI_FUNCTION_TRACE_U32("ps_get_next_simple_arg", arg_type);
 390
 391         switch (arg_type) {
 392         case ARGP_BYTEDATA:
 393
 394                 /* Get 1 byte from the AML stream */
 395
 396                 opcode = AML_BYTE_OP;
 397                 arg->common.value.integer = (acpi_integer) * aml;
 398                 length = 1;
 399                 break;
 400
 401         case ARGP_WORDDATA:
 402
 403                 /* Get 2 bytes from the AML stream */
 404
 405                 opcode = AML_WORD_OP;
 406                 ACPI_MOVE_16_TO_64(&arg->common.value.integer, aml);
 407                 length = 2;
 408                 break;
 409
 410         case ARGP_DWORDDATA:
 411
 412                 /* Get 4 bytes from the AML stream */
 413
 414                 opcode = AML_DWORD_OP;
 415                 ACPI_MOVE_32_TO_64(&arg->common.value.integer, aml);
 416                 length = 4;
 417                 break;
 418
 419         case ARGP_QWORDDATA:
 420
 421                 /* Get 8 bytes from the AML stream */
 422
 423                 opcode = AML_QWORD_OP;
 424                 ACPI_MOVE_64_TO_64(&arg->common.value.integer, aml);
 425                 length = 8;
 426                 break;
 427
 428         case ARGP_CHARLIST:
 429
 430                 /* Get a pointer to the string, point past the string */
 431
 432                 opcode = AML_STRING_OP;
 433                 arg->common.value.string = ACPI_CAST_PTR(char, aml);
 434
 435                 /* Find the null terminator */
 436
 437                 length = 0;
 438                 while (aml[length]) {
 439                         length++;
 440                 }
 441                 length++;
 442                 break;
 443
 444         case ARGP_NAME:
 445         case ARGP_NAMESTRING:
 446
 447                 acpi_ps_init_op(arg, AML_INT_NAMEPATH_OP);
 448                 arg->common.value.name =
 449                     acpi_ps_get_next_namestring(parser_state);
 450                 return_VOID;
 451
 452         default:
 453
 454                 ACPI_REPORT_ERROR(("Invalid arg_type %X\n", arg_type));
 455                 return_VOID;
 456         }
 457
 458         acpi_ps_init_op(arg, opcode);
 459         parser_state->aml += length;
 460         return_VOID;
 461 }
 462
 463 /*******************************************************************************
 464  *
 465  * FUNCTION:    acpi_ps_get_next_field
 466  *
 467  * PARAMETERS:  parser_state        - Current parser state object
 468  *
 469  * RETURN:      A newly allocated FIELD op
 470  *
 471  * DESCRIPTION: Get next field (named_field, reserved_field, or access_field)
 472  *
 473  ******************************************************************************/
 474
 475 static union acpi_parse_object *acpi_ps_get_next_field(struct acpi_parse_state
 476                                                        *parser_state)
 477 {
 478         u32 aml_offset = (u32)
 479             ACPI_PTR_DIFF(parser_state->aml,
 480                           parser_state->aml_start);
 481         union acpi_parse_object *field;
 482         u16 opcode;
 483         u32 name;
 484
 485         ACPI_FUNCTION_TRACE("ps_get_next_field");
 486
 487         /* Determine field type */
 488
 489         switch (ACPI_GET8(parser_state->aml)) {
 490         default:
 491
 492                 opcode = AML_INT_NAMEDFIELD_OP;
 493                 break;
 494
 495         case 0x00:
 496
 497                 opcode = AML_INT_RESERVEDFIELD_OP;
 498                 parser_state->aml++;
 499                 break;
 500
 501         case 0x01:
 502
 503                 opcode = AML_INT_ACCESSFIELD_OP;
 504                 parser_state->aml++;
 505                 break;
 506         }
 507
 508         /* Allocate a new field op */
 509
 510         field = acpi_ps_alloc_op(opcode);
 511         if (!field) {
 512                 return_PTR(NULL);
 513         }
 514
 515         field->common.aml_offset = aml_offset;
 516
 517         /* Decode the field type */
 518
 519         switch (opcode) {
 520         case AML_INT_NAMEDFIELD_OP:
 521
 522                 /* Get the 4-character name */
 523
 524                 ACPI_MOVE_32_TO_32(&name, parser_state->aml);
 525                 acpi_ps_set_name(field, name);
 526                 parser_state->aml += ACPI_NAME_SIZE;
 527
 528                 /* Get the length which is encoded as a package length */
 529
 530                 field->common.value.size =
 531                     acpi_ps_get_next_package_length(parser_state);
 532                 break;
 533
 534         case AML_INT_RESERVEDFIELD_OP:
 535
 536                 /* Get the length which is encoded as a package length */
 537
 538                 field->common.value.size =
 539                     acpi_ps_get_next_package_length(parser_state);
 540                 break;
 541
 542         case AML_INT_ACCESSFIELD_OP:
 543
 544                 /*
 545                  * Get access_type and access_attrib and merge into the field Op
 546                  * access_type is first operand, access_attribute is second
 547                  */
 548                 field->common.value.integer =
 549                     (((u32) ACPI_GET8(parser_state->aml) << 8));
 550                 parser_state->aml++;
 551                 field->common.value.integer |= ACPI_GET8(parser_state->aml);
 552                 parser_state->aml++;
 553                 break;
 554
 555         default:
 556
 557                 /* Opcode was set in previous switch */
 558                 break;
 559         }
 560
 561         return_PTR(field);
 562 }
 563
 564 /*******************************************************************************
 565  *
 566  * FUNCTION:    acpi_ps_get_next_arg
 567  *
 568  * PARAMETERS:  walk_state          - Current state
 569  *              parser_state        - Current parser state object
 570  *              arg_type            - The argument type (AML_*_ARG)
 571  *              return_arg          - Where the next arg is returned
 572  *
 573  * RETURN:      Status, and an op object containing the next argument.
 574  *
 575  * DESCRIPTION: Get next argument (including complex list arguments that require
 576  *              pushing the parser stack)
 577  *
 578  ******************************************************************************/
 579
 580 acpi_status
 581 acpi_ps_get_next_arg(struct acpi_walk_state *walk_state,
 582                      struct acpi_parse_state *parser_state,
 583                      u32 arg_type, union acpi_parse_object **return_arg)
 584 {
 585         union acpi_parse_object *arg = NULL;
 586         union acpi_parse_object *prev = NULL;
 587         union acpi_parse_object *field;
 588         u32 subop;
 589         acpi_status status = AE_OK;
 590
 591         ACPI_FUNCTION_TRACE_PTR("ps_get_next_arg", parser_state);
 592
 593         switch (arg_type) {
 594         case ARGP_BYTEDATA:
 595         case ARGP_WORDDATA:
 596         case ARGP_DWORDDATA:
 597         case ARGP_CHARLIST:
 598         case ARGP_NAME:
 599         case ARGP_NAMESTRING:
 600
 601                 /* Constants, strings, and namestrings are all the same size */
 602
 603                 arg = acpi_ps_alloc_op(AML_BYTE_OP);
 604                 if (!arg) {
 605                         return_ACPI_STATUS(AE_NO_MEMORY);
 606                 }
 607                 acpi_ps_get_next_simple_arg(parser_state, arg_type, arg);
 608                 break;
 609
 610         case ARGP_PKGLENGTH:
 611
 612                 /* Package length, nothing returned */
 613
 614                 parser_state->pkg_end =
 615                     acpi_ps_get_next_package_end(parser_state);
 616                 break;
 617
 618         case ARGP_FIELDLIST:
 619
 620                 if (parser_state->aml < parser_state->pkg_end) {
 621                         /* Non-empty list */
 622
 623                         while (parser_state->aml < parser_state->pkg_end) {
 624                                 field = acpi_ps_get_next_field(parser_state);
 625                                 if (!field) {
 626                                         return_ACPI_STATUS(AE_NO_MEMORY);
 627                                 }
 628
 629                                 if (prev) {
 630                                         prev->common.next = field;
 631                                 } else {
 632                                         arg = field;
 633                                 }
 634                                 prev = field;
 635                         }
 636
 637                         /* Skip to End of byte data */
 638
 639                         parser_state->aml = parser_state->pkg_end;
 640                 }
 641                 break;
 642
 643         case ARGP_BYTELIST:
 644
 645                 if (parser_state->aml < parser_state->pkg_end) {
 646                         /* Non-empty list */
 647
 648                         arg = acpi_ps_alloc_op(AML_INT_BYTELIST_OP);
 649                         if (!arg) {
 650                                 return_ACPI_STATUS(AE_NO_MEMORY);
 651                         }
 652
 653                         /* Fill in bytelist data */
 654
 655                         arg->common.value.size = (u32)
 656                             ACPI_PTR_DIFF(parser_state->pkg_end,
 657                                           parser_state->aml);
 658                         arg->named.data = parser_state->aml;
 659
 660                         /* Skip to End of byte data */
 661
 662                         parser_state->aml = parser_state->pkg_end;
 663                 }
 664                 break;
 665
 666         case ARGP_TARGET:
 667         case ARGP_SUPERNAME:
 668         case ARGP_SIMPLENAME:
 669
 670                 subop = acpi_ps_peek_opcode(parser_state);
 671                 if (subop == 0 ||
 672                     acpi_ps_is_leading_char(subop) ||
 673                     acpi_ps_is_prefix_char(subop)) {
 674                         /* null_name or name_string */
 675
 676                         arg = acpi_ps_alloc_op(AML_INT_NAMEPATH_OP);
 677                         if (!arg) {
 678                                 return_ACPI_STATUS(AE_NO_MEMORY);
 679                         }
 680
 681                         status =
 682                             acpi_ps_get_next_namepath(walk_state, parser_state,
 683                                                       arg, 0);
 684                 } else {
 685                         /* Single complex argument, nothing returned */
 686
 687                         walk_state->arg_count = 1;
 688                 }
 689                 break;
 690
 691         case ARGP_DATAOBJ:
 692         case ARGP_TERMARG:
 693
 694                 /* Single complex argument, nothing returned */
 695
 696                 walk_state->arg_count = 1;
 697                 break;
 698
 699         case ARGP_DATAOBJLIST:
 700         case ARGP_TERMLIST:
 701         case ARGP_OBJLIST:
 702
 703                 if (parser_state->aml < parser_state->pkg_end) {
 704                         /* Non-empty list of variable arguments, nothing returned */
 705
 706                         walk_state->arg_count = ACPI_VAR_ARGS;
 707                 }
 708                 break;
 709
 710         default:
 711
 712                 ACPI_REPORT_ERROR(("Invalid arg_type: %X\n", arg_type));
 713                 status = AE_AML_OPERAND_TYPE;
 714                 break;
 715         }
 716
 717         *return_arg = arg;
 718         return_ACPI_STATUS(status);
 719 }