drivers/acpi/acpica/exmisc.c

   1 /******************************************************************************
   2  *
   3  * Module Name: exmisc - ACPI AML (p-code) execution - specific opcodes
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2016, 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 "acinterp.h"
  47 #include "amlcode.h"
  48 #include "amlresrc.h"
  49
  50 #define _COMPONENT          ACPI_EXECUTER
  51 ACPI_MODULE_NAME("exmisc")
  52
  53 /*******************************************************************************
  54  *
  55  * FUNCTION:    acpi_ex_get_object_reference
  56  *
  57  * PARAMETERS:  obj_desc            - Create a reference to this object
  58  *              return_desc         - Where to store the reference
  59  *              walk_state          - Current state
  60  *
  61  * RETURN:      Status
  62  *
  63  * DESCRIPTION: Obtain and return a "reference" to the target object
  64  *              Common code for the ref_of_op and the cond_ref_of_op.
  65  *
  66  ******************************************************************************/
  67 acpi_status
  68 acpi_ex_get_object_reference(union acpi_operand_object *obj_desc,
  69                              union acpi_operand_object **return_desc,
  70                              struct acpi_walk_state *walk_state)
  71 {
  72         union acpi_operand_object *reference_obj;
  73         union acpi_operand_object *referenced_obj;
  74
  75         ACPI_FUNCTION_TRACE_PTR(ex_get_object_reference, obj_desc);
  76
  77         *return_desc = NULL;
  78
  79         switch (ACPI_GET_DESCRIPTOR_TYPE(obj_desc)) {
  80         case ACPI_DESC_TYPE_OPERAND:
  81
  82                 if (obj_desc->common.type != ACPI_TYPE_LOCAL_REFERENCE) {
  83                         return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
  84                 }
  85
  86                 /*
  87                  * Must be a reference to a Local or Arg
  88                  */
  89                 switch (obj_desc->reference.class) {
  90                 case ACPI_REFCLASS_LOCAL:
  91                 case ACPI_REFCLASS_ARG:
  92                 case ACPI_REFCLASS_DEBUG:
  93
  94                         /* The referenced object is the pseudo-node for the local/arg */
  95
  96                         referenced_obj = obj_desc->reference.object;
  97                         break;
  98
  99                 default:
 100
 101                         ACPI_ERROR((AE_INFO, "Invalid Reference Class 0x%2.2X",
 102                                     obj_desc->reference.class));
 103                         return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
 104                 }
 105                 break;
 106
 107         case ACPI_DESC_TYPE_NAMED:
 108                 /*
 109                  * A named reference that has already been resolved to a Node
 110                  */
 111                 referenced_obj = obj_desc;
 112                 break;
 113
 114         default:
 115
 116                 ACPI_ERROR((AE_INFO, "Invalid descriptor type 0x%X",
 117                             ACPI_GET_DESCRIPTOR_TYPE(obj_desc)));
 118                 return_ACPI_STATUS(AE_TYPE);
 119         }
 120
 121         /* Create a new reference object */
 122
 123         reference_obj =
 124             acpi_ut_create_internal_object(ACPI_TYPE_LOCAL_REFERENCE);
 125         if (!reference_obj) {
 126                 return_ACPI_STATUS(AE_NO_MEMORY);
 127         }
 128
 129         reference_obj->reference.class = ACPI_REFCLASS_REFOF;
 130         reference_obj->reference.object = referenced_obj;
 131         *return_desc = reference_obj;
 132
 133         ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 134                           "Object %p Type [%s], returning Reference %p\n",
 135                           obj_desc, acpi_ut_get_object_type_name(obj_desc),
 136                           *return_desc));
 137
 138         return_ACPI_STATUS(AE_OK);
 139 }
 140
 141 /*******************************************************************************
 142  *
 143  * FUNCTION:    acpi_ex_concat_template
 144  *
 145  * PARAMETERS:  operand0            - First source object
 146  *              operand1            - Second source object
 147  *              actual_return_desc  - Where to place the return object
 148  *              walk_state          - Current walk state
 149  *
 150  * RETURN:      Status
 151  *
 152  * DESCRIPTION: Concatenate two resource templates
 153  *
 154  ******************************************************************************/
 155
 156 acpi_status
 157 acpi_ex_concat_template(union acpi_operand_object *operand0,
 158                         union acpi_operand_object *operand1,
 159                         union acpi_operand_object **actual_return_desc,
 160                         struct acpi_walk_state *walk_state)
 161 {
 162         acpi_status status;
 163         union acpi_operand_object *return_desc;
 164         u8 *new_buf;
 165         u8 *end_tag;
 166         acpi_size length0;
 167         acpi_size length1;
 168         acpi_size new_length;
 169
 170         ACPI_FUNCTION_TRACE(ex_concat_template);
 171
 172         /*
 173          * Find the end_tag descriptor in each resource template.
 174          * Note1: returned pointers point TO the end_tag, not past it.
 175          * Note2: zero-length buffers are allowed; treated like one end_tag
 176          */
 177
 178         /* Get the length of the first resource template */
 179
 180         status = acpi_ut_get_resource_end_tag(operand0, &end_tag);
 181         if (ACPI_FAILURE(status)) {
 182                 return_ACPI_STATUS(status);
 183         }
 184
 185         length0 = ACPI_PTR_DIFF(end_tag, operand0->buffer.pointer);
 186
 187         /* Get the length of the second resource template */
 188
 189         status = acpi_ut_get_resource_end_tag(operand1, &end_tag);
 190         if (ACPI_FAILURE(status)) {
 191                 return_ACPI_STATUS(status);
 192         }
 193
 194         length1 = ACPI_PTR_DIFF(end_tag, operand1->buffer.pointer);
 195
 196         /* Combine both lengths, minimum size will be 2 for end_tag */
 197
 198         new_length = length0 + length1 + sizeof(struct aml_resource_end_tag);
 199
 200         /* Create a new buffer object for the result (with one end_tag) */
 201
 202         return_desc = acpi_ut_create_buffer_object(new_length);
 203         if (!return_desc) {
 204                 return_ACPI_STATUS(AE_NO_MEMORY);
 205         }
 206
 207         /*
 208          * Copy the templates to the new buffer, 0 first, then 1 follows. One
 209          * end_tag descriptor is copied from Operand1.
 210          */
 211         new_buf = return_desc->buffer.pointer;
 212         memcpy(new_buf, operand0->buffer.pointer, length0);
 213         memcpy(new_buf + length0, operand1->buffer.pointer, length1);
 214
 215         /* Insert end_tag and set the checksum to zero, means "ignore checksum" */
 216
 217         new_buf[new_length - 1] = 0;
 218         new_buf[new_length - 2] = ACPI_RESOURCE_NAME_END_TAG | 1;
 219
 220         /* Return the completed resource template */
 221
 222         *actual_return_desc = return_desc;
 223         return_ACPI_STATUS(AE_OK);
 224 }
 225
 226 /*******************************************************************************
 227  *
 228  * FUNCTION:    acpi_ex_do_concatenate
 229  *
 230  * PARAMETERS:  operand0            - First source object
 231  *              operand1            - Second source object
 232  *              actual_return_desc  - Where to place the return object
 233  *              walk_state          - Current walk state
 234  *
 235  * RETURN:      Status
 236  *
 237  * DESCRIPTION: Concatenate two objects OF THE SAME TYPE.
 238  *
 239  ******************************************************************************/
 240
 241 acpi_status
 242 acpi_ex_do_concatenate(union acpi_operand_object *operand0,
 243                        union acpi_operand_object *operand1,
 244                        union acpi_operand_object **actual_return_desc,
 245                        struct acpi_walk_state *walk_state)
 246 {
 247         union acpi_operand_object *local_operand1 = operand1;
 248         union acpi_operand_object *return_desc;
 249         char *new_buf;
 250         const char *type_string;
 251         acpi_status status;
 252
 253         ACPI_FUNCTION_TRACE(ex_do_concatenate);
 254
 255         /*
 256          * Convert the second operand if necessary. The first operand
 257          * determines the type of the second operand, (See the Data Types
 258          * section of the ACPI specification.)  Both object types are
 259          * guaranteed to be either Integer/String/Buffer by the operand
 260          * resolution mechanism.
 261          */
 262         switch (operand0->common.type) {
 263         case ACPI_TYPE_INTEGER:
 264
 265                 status =
 266                     acpi_ex_convert_to_integer(operand1, &local_operand1, 16);
 267                 break;
 268
 269         case ACPI_TYPE_STRING:
 270                 /*
 271                  * Per the ACPI spec, Concatenate only supports int/str/buf.
 272                  * However, we support all objects here as an extension.
 273                  * This improves the usefulness of the Printf() macro.
 274                  * 12/2015.
 275                  */
 276                 switch (operand1->common.type) {
 277                 case ACPI_TYPE_INTEGER:
 278                 case ACPI_TYPE_STRING:
 279                 case ACPI_TYPE_BUFFER:
 280
 281                         status =
 282                             acpi_ex_convert_to_string(operand1, &local_operand1,
 283                                                       ACPI_IMPLICIT_CONVERT_HEX);
 284                         break;
 285
 286                 default:
 287                         /*
 288                          * Just emit a string containing the object type.
 289                          */
 290                         type_string =
 291                             acpi_ut_get_type_name(operand1->common.type);
 292
 293                         local_operand1 = acpi_ut_create_string_object(((acpi_size) strlen(type_string) + 9));   /* 9 For "[Object]" */
 294                         if (!local_operand1) {
 295                                 status = AE_NO_MEMORY;
 296                                 goto cleanup;
 297                         }
 298
 299                         strcpy(local_operand1->string.pointer, "[");
 300                         strcat(local_operand1->string.pointer, type_string);
 301                         strcat(local_operand1->string.pointer, " Object]");
 302                         status = AE_OK;
 303                         break;
 304                 }
 305                 break;
 306
 307         case ACPI_TYPE_BUFFER:
 308
 309                 status = acpi_ex_convert_to_buffer(operand1, &local_operand1);
 310                 break;
 311
 312         default:
 313
 314                 ACPI_ERROR((AE_INFO, "Invalid object type: 0x%X",
 315                             operand0->common.type));
 316                 status = AE_AML_INTERNAL;
 317         }
 318
 319         if (ACPI_FAILURE(status)) {
 320                 goto cleanup;
 321         }
 322
 323         /*
 324          * Both operands are now known to be the same object type
 325          * (Both are Integer, String, or Buffer), and we can now perform the
 326          * concatenation.
 327          */
 328
 329         /*
 330          * There are three cases to handle:
 331          *
 332          * 1) Two Integers concatenated to produce a new Buffer
 333          * 2) Two Strings concatenated to produce a new String
 334          * 3) Two Buffers concatenated to produce a new Buffer
 335          */
 336         switch (operand0->common.type) {
 337         case ACPI_TYPE_INTEGER:
 338
 339                 /* Result of two Integers is a Buffer */
 340                 /* Need enough buffer space for two integers */
 341
 342                 return_desc = acpi_ut_create_buffer_object((acpi_size)
 343                                                            ACPI_MUL_2
 344                                                            (acpi_gbl_integer_byte_width));
 345                 if (!return_desc) {
 346                         status = AE_NO_MEMORY;
 347                         goto cleanup;
 348                 }
 349
 350                 new_buf = (char *)return_desc->buffer.pointer;
 351
 352                 /* Copy the first integer, LSB first */
 353
 354                 memcpy(new_buf, &operand0->integer.value,
 355                        acpi_gbl_integer_byte_width);
 356
 357                 /* Copy the second integer (LSB first) after the first */
 358
 359                 memcpy(new_buf + acpi_gbl_integer_byte_width,
 360                        &local_operand1->integer.value,
 361                        acpi_gbl_integer_byte_width);
 362                 break;
 363
 364         case ACPI_TYPE_STRING:
 365
 366                 /* Result of two Strings is a String */
 367
 368                 return_desc = acpi_ut_create_string_object(((acpi_size)
 369                                                             operand0->string.
 370                                                             length +
 371                                                             local_operand1->
 372                                                             string.length));
 373                 if (!return_desc) {
 374                         status = AE_NO_MEMORY;
 375                         goto cleanup;
 376                 }
 377
 378                 new_buf = return_desc->string.pointer;
 379
 380                 /* Concatenate the strings */
 381
 382                 strcpy(new_buf, operand0->string.pointer);
 383                 strcat(new_buf, local_operand1->string.pointer);
 384                 break;
 385
 386         case ACPI_TYPE_BUFFER:
 387
 388                 /* Result of two Buffers is a Buffer */
 389
 390                 return_desc = acpi_ut_create_buffer_object(((acpi_size)
 391                                                             operand0->buffer.
 392                                                             length +
 393                                                             local_operand1->
 394                                                             buffer.length));
 395                 if (!return_desc) {
 396                         status = AE_NO_MEMORY;
 397                         goto cleanup;
 398                 }
 399
 400                 new_buf = (char *)return_desc->buffer.pointer;
 401
 402                 /* Concatenate the buffers */
 403
 404                 memcpy(new_buf, operand0->buffer.pointer,
 405                        operand0->buffer.length);
 406                 memcpy(new_buf + operand0->buffer.length,
 407                        local_operand1->buffer.pointer,
 408                        local_operand1->buffer.length);
 409                 break;
 410
 411         default:
 412
 413                 /* Invalid object type, should not happen here */
 414
 415                 ACPI_ERROR((AE_INFO, "Invalid object type: 0x%X",
 416                             operand0->common.type));
 417                 status = AE_AML_INTERNAL;
 418                 goto cleanup;
 419         }
 420
 421         *actual_return_desc = return_desc;
 422
 423 cleanup:
 424         if (local_operand1 != operand1) {
 425                 acpi_ut_remove_reference(local_operand1);
 426         }
 427         return_ACPI_STATUS(status);
 428 }
 429
 430 /*******************************************************************************
 431  *
 432  * FUNCTION:    acpi_ex_do_math_op
 433  *
 434  * PARAMETERS:  opcode              - AML opcode
 435  *              integer0            - Integer operand #0
 436  *              integer1            - Integer operand #1
 437  *
 438  * RETURN:      Integer result of the operation
 439  *
 440  * DESCRIPTION: Execute a math AML opcode. The purpose of having all of the
 441  *              math functions here is to prevent a lot of pointer dereferencing
 442  *              to obtain the operands.
 443  *
 444  ******************************************************************************/
 445
 446 u64 acpi_ex_do_math_op(u16 opcode, u64 integer0, u64 integer1)
 447 {
 448
 449         ACPI_FUNCTION_ENTRY();
 450
 451         switch (opcode) {
 452         case AML_ADD_OP:        /* Add (Integer0, Integer1, Result) */
 453
 454                 return (integer0 + integer1);
 455
 456         case AML_BIT_AND_OP:    /* And (Integer0, Integer1, Result) */
 457
 458                 return (integer0 & integer1);
 459
 460         case AML_BIT_NAND_OP:   /* NAnd (Integer0, Integer1, Result) */
 461
 462                 return (~(integer0 & integer1));
 463
 464         case AML_BIT_OR_OP:     /* Or (Integer0, Integer1, Result) */
 465
 466                 return (integer0 | integer1);
 467
 468         case AML_BIT_NOR_OP:    /* NOr (Integer0, Integer1, Result) */
 469
 470                 return (~(integer0 | integer1));
 471
 472         case AML_BIT_XOR_OP:    /* XOr (Integer0, Integer1, Result) */
 473
 474                 return (integer0 ^ integer1);
 475
 476         case AML_MULTIPLY_OP:   /* Multiply (Integer0, Integer1, Result) */
 477
 478                 return (integer0 * integer1);
 479
 480         case AML_SHIFT_LEFT_OP: /* shift_left (Operand, shift_count, Result) */
 481
 482                 /*
 483                  * We need to check if the shiftcount is larger than the integer bit
 484                  * width since the behavior of this is not well-defined in the C language.
 485                  */
 486                 if (integer1 >= acpi_gbl_integer_bit_width) {
 487                         return (0);
 488                 }
 489                 return (integer0 << integer1);
 490
 491         case AML_SHIFT_RIGHT_OP:        /* shift_right (Operand, shift_count, Result) */
 492
 493                 /*
 494                  * We need to check if the shiftcount is larger than the integer bit
 495                  * width since the behavior of this is not well-defined in the C language.
 496                  */
 497                 if (integer1 >= acpi_gbl_integer_bit_width) {
 498                         return (0);
 499                 }
 500                 return (integer0 >> integer1);
 501
 502         case AML_SUBTRACT_OP:   /* Subtract (Integer0, Integer1, Result) */
 503
 504                 return (integer0 - integer1);
 505
 506         default:
 507
 508                 return (0);
 509         }
 510 }
 511
 512 /*******************************************************************************
 513  *
 514  * FUNCTION:    acpi_ex_do_logical_numeric_op
 515  *
 516  * PARAMETERS:  opcode              - AML opcode
 517  *              integer0            - Integer operand #0
 518  *              integer1            - Integer operand #1
 519  *              logical_result      - TRUE/FALSE result of the operation
 520  *
 521  * RETURN:      Status
 522  *
 523  * DESCRIPTION: Execute a logical "Numeric" AML opcode. For these Numeric
 524  *              operators (LAnd and LOr), both operands must be integers.
 525  *
 526  *              Note: cleanest machine code seems to be produced by the code
 527  *              below, rather than using statements of the form:
 528  *                  Result = (Integer0 && Integer1);
 529  *
 530  ******************************************************************************/
 531
 532 acpi_status
 533 acpi_ex_do_logical_numeric_op(u16 opcode,
 534                               u64 integer0, u64 integer1, u8 *logical_result)
 535 {
 536         acpi_status status = AE_OK;
 537         u8 local_result = FALSE;
 538
 539         ACPI_FUNCTION_TRACE(ex_do_logical_numeric_op);
 540
 541         switch (opcode) {
 542         case AML_LAND_OP:       /* LAnd (Integer0, Integer1) */
 543
 544                 if (integer0 && integer1) {
 545                         local_result = TRUE;
 546                 }
 547                 break;
 548
 549         case AML_LOR_OP:        /* LOr (Integer0, Integer1) */
 550
 551                 if (integer0 || integer1) {
 552                         local_result = TRUE;
 553                 }
 554                 break;
 555
 556         default:
 557
 558                 status = AE_AML_INTERNAL;
 559                 break;
 560         }
 561
 562         /* Return the logical result and status */
 563
 564         *logical_result = local_result;
 565         return_ACPI_STATUS(status);
 566 }
 567
 568 /*******************************************************************************
 569  *
 570  * FUNCTION:    acpi_ex_do_logical_op
 571  *
 572  * PARAMETERS:  opcode              - AML opcode
 573  *              operand0            - operand #0
 574  *              operand1            - operand #1
 575  *              logical_result      - TRUE/FALSE result of the operation
 576  *
 577  * RETURN:      Status
 578  *
 579  * DESCRIPTION: Execute a logical AML opcode. The purpose of having all of the
 580  *              functions here is to prevent a lot of pointer dereferencing
 581  *              to obtain the operands and to simplify the generation of the
 582  *              logical value. For the Numeric operators (LAnd and LOr), both
 583  *              operands must be integers. For the other logical operators,
 584  *              operands can be any combination of Integer/String/Buffer. The
 585  *              first operand determines the type to which the second operand
 586  *              will be converted.
 587  *
 588  *              Note: cleanest machine code seems to be produced by the code
 589  *              below, rather than using statements of the form:
 590  *                  Result = (Operand0 == Operand1);
 591  *
 592  ******************************************************************************/
 593
 594 acpi_status
 595 acpi_ex_do_logical_op(u16 opcode,
 596                       union acpi_operand_object *operand0,
 597                       union acpi_operand_object *operand1, u8 * logical_result)
 598 {
 599         union acpi_operand_object *local_operand1 = operand1;
 600         u64 integer0;
 601         u64 integer1;
 602         u32 length0;
 603         u32 length1;
 604         acpi_status status = AE_OK;
 605         u8 local_result = FALSE;
 606         int compare;
 607
 608         ACPI_FUNCTION_TRACE(ex_do_logical_op);
 609
 610         /*
 611          * Convert the second operand if necessary. The first operand
 612          * determines the type of the second operand, (See the Data Types
 613          * section of the ACPI 3.0+ specification.)  Both object types are
 614          * guaranteed to be either Integer/String/Buffer by the operand
 615          * resolution mechanism.
 616          */
 617         switch (operand0->common.type) {
 618         case ACPI_TYPE_INTEGER:
 619
 620                 status =
 621                     acpi_ex_convert_to_integer(operand1, &local_operand1, 16);
 622                 break;
 623
 624         case ACPI_TYPE_STRING:
 625
 626                 status =
 627                     acpi_ex_convert_to_string(operand1, &local_operand1,
 628                                               ACPI_IMPLICIT_CONVERT_HEX);
 629                 break;
 630
 631         case ACPI_TYPE_BUFFER:
 632
 633                 status = acpi_ex_convert_to_buffer(operand1, &local_operand1);
 634                 break;
 635
 636         default:
 637
 638                 status = AE_AML_INTERNAL;
 639                 break;
 640         }
 641
 642         if (ACPI_FAILURE(status)) {
 643                 goto cleanup;
 644         }
 645
 646         /*
 647          * Two cases: 1) Both Integers, 2) Both Strings or Buffers
 648          */
 649         if (operand0->common.type == ACPI_TYPE_INTEGER) {
 650                 /*
 651                  * 1) Both operands are of type integer
 652                  *    Note: local_operand1 may have changed above
 653                  */
 654                 integer0 = operand0->integer.value;
 655                 integer1 = local_operand1->integer.value;
 656
 657                 switch (opcode) {
 658                 case AML_LEQUAL_OP:     /* LEqual (Operand0, Operand1) */
 659
 660                         if (integer0 == integer1) {
 661                                 local_result = TRUE;
 662                         }
 663                         break;
 664
 665                 case AML_LGREATER_OP:   /* LGreater (Operand0, Operand1) */
 666
 667                         if (integer0 > integer1) {
 668                                 local_result = TRUE;
 669                         }
 670                         break;
 671
 672                 case AML_LLESS_OP:      /* LLess (Operand0, Operand1) */
 673
 674                         if (integer0 < integer1) {
 675                                 local_result = TRUE;
 676                         }
 677                         break;
 678
 679                 default:
 680
 681                         status = AE_AML_INTERNAL;
 682                         break;
 683                 }
 684         } else {
 685                 /*
 686                  * 2) Both operands are Strings or both are Buffers
 687                  *    Note: Code below takes advantage of common Buffer/String
 688                  *          object fields. local_operand1 may have changed above. Use
 689                  *          memcmp to handle nulls in buffers.
 690                  */
 691                 length0 = operand0->buffer.length;
 692                 length1 = local_operand1->buffer.length;
 693
 694                 /* Lexicographic compare: compare the data bytes */
 695
 696                 compare = memcmp(operand0->buffer.pointer,
 697                                  local_operand1->buffer.pointer,
 698                                  (length0 > length1) ? length1 : length0);
 699
 700                 switch (opcode) {
 701                 case AML_LEQUAL_OP:     /* LEqual (Operand0, Operand1) */
 702
 703                         /* Length and all bytes must be equal */
 704
 705                         if ((length0 == length1) && (compare == 0)) {
 706
 707                                 /* Length and all bytes match ==> TRUE */
 708
 709                                 local_result = TRUE;
 710                         }
 711                         break;
 712
 713                 case AML_LGREATER_OP:   /* LGreater (Operand0, Operand1) */
 714
 715                         if (compare > 0) {
 716                                 local_result = TRUE;
 717                                 goto cleanup;   /* TRUE */
 718                         }
 719                         if (compare < 0) {
 720                                 goto cleanup;   /* FALSE */
 721                         }
 722
 723                         /* Bytes match (to shortest length), compare lengths */
 724
 725                         if (length0 > length1) {
 726                                 local_result = TRUE;
 727                         }
 728                         break;
 729
 730                 case AML_LLESS_OP:      /* LLess (Operand0, Operand1) */
 731
 732                         if (compare > 0) {
 733                                 goto cleanup;   /* FALSE */
 734                         }
 735                         if (compare < 0) {
 736                                 local_result = TRUE;
 737                                 goto cleanup;   /* TRUE */
 738                         }
 739
 740                         /* Bytes match (to shortest length), compare lengths */
 741
 742                         if (length0 < length1) {
 743                                 local_result = TRUE;
 744                         }
 745                         break;
 746
 747                 default:
 748
 749                         status = AE_AML_INTERNAL;
 750                         break;
 751                 }
 752         }
 753
 754 cleanup:
 755
 756         /* New object was created if implicit conversion performed - delete */
 757
 758         if (local_operand1 != operand1) {
 759                 acpi_ut_remove_reference(local_operand1);
 760         }
 761
 762         /* Return the logical result and status */
 763
 764         *logical_result = local_result;
 765         return_ACPI_STATUS(status);
 766 }