drivers/acpi/acpica/psargs.c

   1 /******************************************************************************
   2  *
   3  * Module Name: psargs - Parse AML opcode arguments
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2008, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46 #include "acparser.h"
  47 #include "amlcode.h"
  48 #include "acnamesp.h"
  49 #include "acdispat.h"
  50
  51 #define _COMPONENT          ACPI_PARSER
  52 ACPI_MODULE_NAME("psargs")
  53
  54 /* Local prototypes */
  55 static u32
  56 acpi_ps_get_next_package_length(struct acpi_parse_state *parser_state);
  57
  58 static union acpi_parse_object *acpi_ps_get_next_field(struct acpi_parse_state
  59                                                        *parser_state);
  60
  61 /*******************************************************************************
  62  *
  63  * FUNCTION:    acpi_ps_get_next_package_length
  64  *
  65  * PARAMETERS:  parser_state        - Current parser state object
  66  *
  67  * RETURN:      Decoded package length. On completion, the AML pointer points
  68  *              past the length byte or bytes.
  69  *
  70  * DESCRIPTION: Decode and return a package length field.
  71  *              Note: Largest package length is 28 bits, from ACPI specification
  72  *
  73  ******************************************************************************/
  74
  75 static u32
  76 acpi_ps_get_next_package_length(struct acpi_parse_state *parser_state)
  77 {
  78         u8 *aml = parser_state->aml;
  79         u32 package_length = 0;
  80         u32 byte_count;
  81         u8 byte_zero_mask = 0x3F;       /* Default [0:5] */
  82
  83         ACPI_FUNCTION_TRACE(ps_get_next_package_length);
  84
  85         /*
  86          * Byte 0 bits [6:7] contain the number of additional bytes
  87          * used to encode the package length, either 0,1,2, or 3
  88          */
  89         byte_count = (aml[0] >> 6);
  90         parser_state->aml += ((acpi_size) byte_count + 1);
  91
  92         /* Get bytes 3, 2, 1 as needed */
  93
  94         while (byte_count) {
  95                 /*
  96                  * Final bit positions for the package length bytes:
  97                  *      Byte3->[20:27]
  98                  *      Byte2->[12:19]
  99                  *      Byte1->[04:11]
 100                  *      Byte0->[00:03]
 101                  */
 102                 package_length |= (aml[byte_count] << ((byte_count << 3) - 4));
 103
 104                 byte_zero_mask = 0x0F;  /* Use bits [0:3] of byte 0 */
 105                 byte_count--;
 106         }
 107
 108         /* Byte 0 is a special case, either bits [0:3] or [0:5] are used */
 109
 110         package_length |= (aml[0] & byte_zero_mask);
 111         return_UINT32(package_length);
 112 }
 113
 114 /*******************************************************************************
 115  *
 116  * FUNCTION:    acpi_ps_get_next_package_end
 117  *
 118  * PARAMETERS:  parser_state        - Current parser state object
 119  *
 120  * RETURN:      Pointer to end-of-package +1
 121  *
 122  * DESCRIPTION: Get next package length and return a pointer past the end of
 123  *              the package.  Consumes the package length field
 124  *
 125  ******************************************************************************/
 126
 127 u8 *acpi_ps_get_next_package_end(struct acpi_parse_state *parser_state)
 128 {
 129         u8 *start = parser_state->aml;
 130         u32 package_length;
 131
 132         ACPI_FUNCTION_TRACE(ps_get_next_package_end);
 133
 134         /* Function below updates parser_state->Aml */
 135
 136         package_length = acpi_ps_get_next_package_length(parser_state);
 137
 138         return_PTR(start + package_length);     /* end of package */
 139 }
 140
 141 /*******************************************************************************
 142  *
 143  * FUNCTION:    acpi_ps_get_next_namestring
 144  *
 145  * PARAMETERS:  parser_state        - Current parser state object
 146  *
 147  * RETURN:      Pointer to the start of the name string (pointer points into
 148  *              the AML.
 149  *
 150  * DESCRIPTION: Get next raw namestring within the AML stream.  Handles all name
 151  *              prefix characters.  Set parser state to point past the string.
 152  *              (Name is consumed from the AML.)
 153  *
 154  ******************************************************************************/
 155
 156 char *acpi_ps_get_next_namestring(struct acpi_parse_state *parser_state)
 157 {
 158         u8 *start = parser_state->aml;
 159         u8 *end = parser_state->aml;
 160
 161         ACPI_FUNCTION_TRACE(ps_get_next_namestring);
 162
 163         /* Point past any namestring prefix characters (backslash or carat) */
 164
 165         while (acpi_ps_is_prefix_char(*end)) {
 166                 end++;
 167         }
 168
 169         /* Decode the path prefix character */
 170
 171         switch (*end) {
 172         case 0:
 173
 174                 /* null_name */
 175
 176                 if (end == start) {
 177                         start = NULL;
 178                 }
 179                 end++;
 180                 break;
 181
 182         case AML_DUAL_NAME_PREFIX:
 183
 184                 /* Two name segments */
 185
 186                 end += 1 + (2 * ACPI_NAME_SIZE);
 187                 break;
 188
 189         case AML_MULTI_NAME_PREFIX_OP:
 190
 191                 /* Multiple name segments, 4 chars each, count in next byte */
 192
 193                 end += 2 + (*(end + 1) * ACPI_NAME_SIZE);
 194                 break;
 195
 196         default:
 197
 198                 /* Single name segment */
 199
 200                 end += ACPI_NAME_SIZE;
 201                 break;
 202         }
 203
 204         parser_state->aml = end;
 205         return_PTR((char *)start);
 206 }
 207
 208 /*******************************************************************************
 209  *
 210  * FUNCTION:    acpi_ps_get_next_namepath
 211  *
 212  * PARAMETERS:  parser_state        - Current parser state object
 213  *              Arg                 - Where the namepath will be stored
 214  *              arg_count           - If the namepath points to a control method
 215  *                                    the method's argument is returned here.
 216  *              possible_method_call - Whether the namepath can possibly be the
 217  *                                    start of a method call
 218  *
 219  * RETURN:      Status
 220  *
 221  * DESCRIPTION: Get next name (if method call, return # of required args).
 222  *              Names are looked up in the internal namespace to determine
 223  *              if the name represents a control method.  If a method
 224  *              is found, the number of arguments to the method is returned.
 225  *              This information is critical for parsing to continue correctly.
 226  *
 227  ******************************************************************************/
 228
 229 acpi_status
 230 acpi_ps_get_next_namepath(struct acpi_walk_state *walk_state,
 231                           struct acpi_parse_state *parser_state,
 232                           union acpi_parse_object *arg, u8 possible_method_call)
 233 {
 234         acpi_status status;
 235         char *path;
 236         union acpi_parse_object *name_op;
 237         union acpi_operand_object *method_desc;
 238         struct acpi_namespace_node *node;
 239         u8 *start = parser_state->aml;
 240
 241         ACPI_FUNCTION_TRACE(ps_get_next_namepath);
 242
 243         path = acpi_ps_get_next_namestring(parser_state);
 244         acpi_ps_init_op(arg, AML_INT_NAMEPATH_OP);
 245
 246         /* Null path case is allowed, just exit */
 247
 248         if (!path) {
 249                 arg->common.value.name = path;
 250                 return_ACPI_STATUS(AE_OK);
 251         }
 252
 253         /*
 254          * Lookup the name in the internal namespace, starting with the current
 255          * scope. We don't want to add anything new to the namespace here,
 256          * however, so we use MODE_EXECUTE.
 257          * Allow searching of the parent tree, but don't open a new scope -
 258          * we just want to lookup the object (must be mode EXECUTE to perform
 259          * the upsearch)
 260          */
 261         status = acpi_ns_lookup(walk_state->scope_info, path,
 262                                 ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
 263                                 ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE,
 264                                 NULL, &node);
 265
 266         /*
 267          * If this name is a control method invocation, we must
 268          * setup the method call
 269          */
 270         if (ACPI_SUCCESS(status) &&
 271             possible_method_call && (node->type == ACPI_TYPE_METHOD)) {
 272                 if (walk_state->opcode == AML_UNLOAD_OP) {
 273                         /*
 274                          * acpi_ps_get_next_namestring has increased the AML pointer,
 275                          * so we need to restore the saved AML pointer for method call.
 276                          */
 277                         walk_state->parser_state.aml = start;
 278                         walk_state->arg_count = 1;
 279                         acpi_ps_init_op(arg, AML_INT_METHODCALL_OP);
 280                         return_ACPI_STATUS(AE_OK);
 281                 }
 282
 283                 /* This name is actually a control method invocation */
 284
 285                 method_desc = acpi_ns_get_attached_object(node);
 286                 ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 287                                   "Control Method - %p Desc %p Path=%p\n", node,
 288                                   method_desc, path));
 289
 290                 name_op = acpi_ps_alloc_op(AML_INT_NAMEPATH_OP);
 291                 if (!name_op) {
 292                         return_ACPI_STATUS(AE_NO_MEMORY);
 293                 }
 294
 295                 /* Change Arg into a METHOD CALL and attach name to it */
 296
 297                 acpi_ps_init_op(arg, AML_INT_METHODCALL_OP);
 298                 name_op->common.value.name = path;
 299
 300                 /* Point METHODCALL/NAME to the METHOD Node */
 301
 302                 name_op->common.node = node;
 303                 acpi_ps_append_arg(arg, name_op);
 304
 305                 if (!method_desc) {
 306                         ACPI_ERROR((AE_INFO,
 307                                     "Control Method %p has no attached object",
 308                                     node));
 309                         return_ACPI_STATUS(AE_AML_INTERNAL);
 310                 }
 311
 312                 ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
 313                                   "Control Method - %p Args %X\n",
 314                                   node, method_desc->method.param_count));
 315
 316                 /* Get the number of arguments to expect */
 317
 318                 walk_state->arg_count = method_desc->method.param_count;
 319                 return_ACPI_STATUS(AE_OK);
 320         }
 321
 322         /*
 323          * Special handling if the name was not found during the lookup -
 324          * some not_found cases are allowed
 325          */
 326         if (status == AE_NOT_FOUND) {
 327
 328                 /* 1) not_found is ok during load pass 1/2 (allow forward references) */
 329
 330                 if ((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) !=
 331                     ACPI_PARSE_EXECUTE) {
 332                         status = AE_OK;
 333                 }
 334
 335                 /* 2) not_found during a cond_ref_of(x) is ok by definition */
 336
 337                 else if (walk_state->op->common.aml_opcode ==
 338                          AML_COND_REF_OF_OP) {
 339                         status = AE_OK;
 340                 }
 341
 342                 /*
 343                  * 3) not_found while building a Package is ok at this point, we
 344                  * may flag as an error later if slack mode is not enabled.
 345                  * (Some ASL code depends on allowing this behavior)
 346                  */
 347                 else if ((arg->common.parent) &&
 348                          ((arg->common.parent->common.aml_opcode ==
 349                            AML_PACKAGE_OP)
 350                           || (arg->common.parent->common.aml_opcode ==
 351                               AML_VAR_PACKAGE_OP))) {
 352                         status = AE_OK;
 353                 }
 354         }
 355
 356         /* Final exception check (may have been changed from code above) */
 357
 358         if (ACPI_FAILURE(status)) {
 359                 ACPI_ERROR_NAMESPACE(path, status);
 360
 361                 if ((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) ==
 362                     ACPI_PARSE_EXECUTE) {
 363
 364                         /* Report a control method execution error */
 365
 366                         status = acpi_ds_method_error(status, walk_state);
 367                 }
 368         }
 369
 370         /* Save the namepath */
 371
 372         arg->common.value.name = path;
 373         return_ACPI_STATUS(status);
 374 }
 375
 376 /*******************************************************************************
 377  *
 378  * FUNCTION:    acpi_ps_get_next_simple_arg
 379  *
 380  * PARAMETERS:  parser_state        - Current parser state object
 381  *              arg_type            - The argument type (AML_*_ARG)
 382  *              Arg                 - Where the argument is returned
 383  *
 384  * RETURN:      None
 385  *
 386  * DESCRIPTION: Get the next simple argument (constant, string, or namestring)
 387  *
 388  ******************************************************************************/
 389
 390 void
 391 acpi_ps_get_next_simple_arg(struct acpi_parse_state *parser_state,
 392                             u32 arg_type, union acpi_parse_object *arg)
 393 {
 394         u32 length;
 395         u16 opcode;
 396         u8 *aml = parser_state->aml;
 397
 398         ACPI_FUNCTION_TRACE_U32(ps_get_next_simple_arg, arg_type);
 399
 400         switch (arg_type) {
 401         case ARGP_BYTEDATA:
 402
 403                 /* Get 1 byte from the AML stream */
 404
 405                 opcode = AML_BYTE_OP;
 406                 arg->common.value.integer = (acpi_integer) * aml;
 407                 length = 1;
 408                 break;
 409
 410         case ARGP_WORDDATA:
 411
 412                 /* Get 2 bytes from the AML stream */
 413
 414                 opcode = AML_WORD_OP;
 415                 ACPI_MOVE_16_TO_64(&arg->common.value.integer, aml);
 416                 length = 2;
 417                 break;
 418
 419         case ARGP_DWORDDATA:
 420
 421                 /* Get 4 bytes from the AML stream */
 422
 423                 opcode = AML_DWORD_OP;
 424                 ACPI_MOVE_32_TO_64(&arg->common.value.integer, aml);
 425                 length = 4;
 426                 break;
 427
 428         case ARGP_QWORDDATA:
 429
 430                 /* Get 8 bytes from the AML stream */
 431
 432                 opcode = AML_QWORD_OP;
 433                 ACPI_MOVE_64_TO_64(&arg->common.value.integer, aml);
 434                 length = 8;
 435                 break;
 436
 437         case ARGP_CHARLIST:
 438
 439                 /* Get a pointer to the string, point past the string */
 440
 441                 opcode = AML_STRING_OP;
 442                 arg->common.value.string = ACPI_CAST_PTR(char, aml);
 443
 444                 /* Find the null terminator */
 445
 446                 length = 0;
 447                 while (aml[length]) {
 448                         length++;
 449                 }
 450                 length++;
 451                 break;
 452
 453         case ARGP_NAME:
 454         case ARGP_NAMESTRING:
 455
 456                 acpi_ps_init_op(arg, AML_INT_NAMEPATH_OP);
 457                 arg->common.value.name =
 458                     acpi_ps_get_next_namestring(parser_state);
 459                 return_VOID;
 460
 461         default:
 462
 463                 ACPI_ERROR((AE_INFO, "Invalid ArgType %X", arg_type));
 464                 return_VOID;
 465         }
 466
 467         acpi_ps_init_op(arg, opcode);
 468         parser_state->aml += length;
 469         return_VOID;
 470 }
 471
 472 /*******************************************************************************
 473  *
 474  * FUNCTION:    acpi_ps_get_next_field
 475  *
 476  * PARAMETERS:  parser_state        - Current parser state object
 477  *
 478  * RETURN:      A newly allocated FIELD op
 479  *
 480  * DESCRIPTION: Get next field (named_field, reserved_field, or access_field)
 481  *
 482  ******************************************************************************/
 483
 484 static union acpi_parse_object *acpi_ps_get_next_field(struct acpi_parse_state
 485                                                        *parser_state)
 486 {
 487         u32 aml_offset = (u32)
 488             ACPI_PTR_DIFF(parser_state->aml,
 489                           parser_state->aml_start);
 490         union acpi_parse_object *field;
 491         u16 opcode;
 492         u32 name;
 493
 494         ACPI_FUNCTION_TRACE(ps_get_next_field);
 495
 496         /* Determine field type */
 497
 498         switch (ACPI_GET8(parser_state->aml)) {
 499         default:
 500
 501                 opcode = AML_INT_NAMEDFIELD_OP;
 502                 break;
 503
 504         case 0x00:
 505
 506                 opcode = AML_INT_RESERVEDFIELD_OP;
 507                 parser_state->aml++;
 508                 break;
 509
 510         case 0x01:
 511
 512                 opcode = AML_INT_ACCESSFIELD_OP;
 513                 parser_state->aml++;
 514                 break;
 515         }
 516
 517         /* Allocate a new field op */
 518
 519         field = acpi_ps_alloc_op(opcode);
 520         if (!field) {
 521                 return_PTR(NULL);
 522         }
 523
 524         field->common.aml_offset = aml_offset;
 525
 526         /* Decode the field type */
 527
 528         switch (opcode) {
 529         case AML_INT_NAMEDFIELD_OP:
 530
 531                 /* Get the 4-character name */
 532
 533                 ACPI_MOVE_32_TO_32(&name, parser_state->aml);
 534                 acpi_ps_set_name(field, name);
 535                 parser_state->aml += ACPI_NAME_SIZE;
 536
 537                 /* Get the length which is encoded as a package length */
 538
 539                 field->common.value.size =
 540                     acpi_ps_get_next_package_length(parser_state);
 541                 break;
 542
 543         case AML_INT_RESERVEDFIELD_OP:
 544
 545                 /* Get the length which is encoded as a package length */
 546
 547                 field->common.value.size =
 548                     acpi_ps_get_next_package_length(parser_state);
 549                 break;
 550
 551         case AML_INT_ACCESSFIELD_OP:
 552
 553                 /*
 554                  * Get access_type and access_attrib and merge into the field Op
 555                  * access_type is first operand, access_attribute is second
 556                  */
 557                 field->common.value.integer =
 558                     (((u32) ACPI_GET8(parser_state->aml) << 8));
 559                 parser_state->aml++;
 560                 field->common.value.integer |= ACPI_GET8(parser_state->aml);
 561                 parser_state->aml++;
 562                 break;
 563
 564         default:
 565
 566                 /* Opcode was set in previous switch */
 567                 break;
 568         }
 569
 570         return_PTR(field);
 571 }
 572
 573 /*******************************************************************************
 574  *
 575  * FUNCTION:    acpi_ps_get_next_arg
 576  *
 577  * PARAMETERS:  walk_state          - Current state
 578  *              parser_state        - Current parser state object
 579  *              arg_type            - The argument type (AML_*_ARG)
 580  *              return_arg          - Where the next arg is returned
 581  *
 582  * RETURN:      Status, and an op object containing the next argument.
 583  *
 584  * DESCRIPTION: Get next argument (including complex list arguments that require
 585  *              pushing the parser stack)
 586  *
 587  ******************************************************************************/
 588
 589 acpi_status
 590 acpi_ps_get_next_arg(struct acpi_walk_state *walk_state,
 591                      struct acpi_parse_state *parser_state,
 592                      u32 arg_type, union acpi_parse_object **return_arg)
 593 {
 594         union acpi_parse_object *arg = NULL;
 595         union acpi_parse_object *prev = NULL;
 596         union acpi_parse_object *field;
 597         u32 subop;
 598         acpi_status status = AE_OK;
 599
 600         ACPI_FUNCTION_TRACE_PTR(ps_get_next_arg, parser_state);
 601
 602         switch (arg_type) {
 603         case ARGP_BYTEDATA:
 604         case ARGP_WORDDATA:
 605         case ARGP_DWORDDATA:
 606         case ARGP_CHARLIST:
 607         case ARGP_NAME:
 608         case ARGP_NAMESTRING:
 609
 610                 /* Constants, strings, and namestrings are all the same size */
 611
 612                 arg = acpi_ps_alloc_op(AML_BYTE_OP);
 613                 if (!arg) {
 614                         return_ACPI_STATUS(AE_NO_MEMORY);
 615                 }
 616                 acpi_ps_get_next_simple_arg(parser_state, arg_type, arg);
 617                 break;
 618
 619         case ARGP_PKGLENGTH:
 620
 621                 /* Package length, nothing returned */
 622
 623                 parser_state->pkg_end =
 624                     acpi_ps_get_next_package_end(parser_state);
 625                 break;
 626
 627         case ARGP_FIELDLIST:
 628
 629                 if (parser_state->aml < parser_state->pkg_end) {
 630
 631                         /* Non-empty list */
 632
 633                         while (parser_state->aml < parser_state->pkg_end) {
 634                                 field = acpi_ps_get_next_field(parser_state);
 635                                 if (!field) {
 636                                         return_ACPI_STATUS(AE_NO_MEMORY);
 637                                 }
 638
 639                                 if (prev) {
 640                                         prev->common.next = field;
 641                                 } else {
 642                                         arg = field;
 643                                 }
 644                                 prev = field;
 645                         }
 646
 647                         /* Skip to End of byte data */
 648
 649                         parser_state->aml = parser_state->pkg_end;
 650                 }
 651                 break;
 652
 653         case ARGP_BYTELIST:
 654
 655                 if (parser_state->aml < parser_state->pkg_end) {
 656
 657                         /* Non-empty list */
 658
 659                         arg = acpi_ps_alloc_op(AML_INT_BYTELIST_OP);
 660                         if (!arg) {
 661                                 return_ACPI_STATUS(AE_NO_MEMORY);
 662                         }
 663
 664                         /* Fill in bytelist data */
 665
 666                         arg->common.value.size = (u32)
 667                             ACPI_PTR_DIFF(parser_state->pkg_end,
 668                                           parser_state->aml);
 669                         arg->named.data = parser_state->aml;
 670
 671                         /* Skip to End of byte data */
 672
 673                         parser_state->aml = parser_state->pkg_end;
 674                 }
 675                 break;
 676
 677         case ARGP_TARGET:
 678         case ARGP_SUPERNAME:
 679         case ARGP_SIMPLENAME:
 680
 681                 subop = acpi_ps_peek_opcode(parser_state);
 682                 if (subop == 0 ||
 683                     acpi_ps_is_leading_char(subop) ||
 684                     acpi_ps_is_prefix_char(subop)) {
 685
 686                         /* null_name or name_string */
 687
 688                         arg = acpi_ps_alloc_op(AML_INT_NAMEPATH_OP);
 689                         if (!arg) {
 690                                 return_ACPI_STATUS(AE_NO_MEMORY);
 691                         }
 692
 693                         /* To support super_name arg of Unload */
 694
 695                         if (walk_state->opcode == AML_UNLOAD_OP) {
 696                                 status =
 697                                     acpi_ps_get_next_namepath(walk_state,
 698                                                               parser_state, arg,
 699                                                               1);
 700
 701                                 /*
 702                                  * If the super_name arg of Unload is a method call,
 703                                  * we have restored the AML pointer, just free this Arg
 704                                  */
 705                                 if (arg->common.aml_opcode ==
 706                                     AML_INT_METHODCALL_OP) {
 707                                         acpi_ps_free_op(arg);
 708                                         arg = NULL;
 709                                 }
 710                         } else {
 711                                 status =
 712                                     acpi_ps_get_next_namepath(walk_state,
 713                                                               parser_state, arg,
 714                                                               0);
 715                         }
 716                 } else {
 717                         /* Single complex argument, nothing returned */
 718
 719                         walk_state->arg_count = 1;
 720                 }
 721                 break;
 722
 723         case ARGP_DATAOBJ:
 724         case ARGP_TERMARG:
 725
 726                 /* Single complex argument, nothing returned */
 727
 728                 walk_state->arg_count = 1;
 729                 break;
 730
 731         case ARGP_DATAOBJLIST:
 732         case ARGP_TERMLIST:
 733         case ARGP_OBJLIST:
 734
 735                 if (parser_state->aml < parser_state->pkg_end) {
 736
 737                         /* Non-empty list of variable arguments, nothing returned */
 738
 739                         walk_state->arg_count = ACPI_VAR_ARGS;
 740                 }
 741                 break;
 742
 743         default:
 744
 745                 ACPI_ERROR((AE_INFO, "Invalid ArgType: %X", arg_type));
 746                 status = AE_AML_OPERAND_TYPE;
 747                 break;
 748         }
 749
 750         *return_arg = arg;
 751         return_ACPI_STATUS(status);
 752 }