drivers/acpi/acpica/tbutils.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbutils   - table utilities
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2012, 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 "actables.h"
  47
  48 #define _COMPONENT          ACPI_TABLES
  49 ACPI_MODULE_NAME("tbutils")
  50
  51 /* Local prototypes */
  52 static void acpi_tb_fix_string(char *string, acpi_size length);
  53
  54 static void
  55 acpi_tb_cleanup_table_header(struct acpi_table_header *out_header,
  56                              struct acpi_table_header *header);
  57
  58 static acpi_physical_address
  59 acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size);
  60
  61 /*******************************************************************************
  62  *
  63  * FUNCTION:    acpi_tb_check_xsdt
  64  *
  65  * PARAMETERS:  address                    - Pointer to the XSDT
  66  *
  67  * RETURN:      status
  68  *              AE_OK - XSDT is okay
  69  *              AE_NO_MEMORY - can't map XSDT
  70  *              AE_INVALID_TABLE_LENGTH - invalid table length
  71  *              AE_NULL_ENTRY - XSDT has NULL entry
  72  *
  73  * DESCRIPTION: validate XSDT
  74 ******************************************************************************/
  75
  76 static acpi_status
  77 acpi_tb_check_xsdt(acpi_physical_address address)
  78 {
  79         struct acpi_table_header *table;
  80         u32 length;
  81         u64 xsdt_entry_address;
  82         u8 *table_entry;
  83         u32 table_count;
  84         int i;
  85
  86         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
  87         if (!table)
  88                 return AE_NO_MEMORY;
  89
  90         length = table->length;
  91         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
  92         if (length < sizeof(struct acpi_table_header))
  93                 return AE_INVALID_TABLE_LENGTH;
  94
  95         table = acpi_os_map_memory(address, length);
  96         if (!table)
  97                 return AE_NO_MEMORY;
  98
  99         /* Calculate the number of tables described in XSDT */
 100         table_count =
 101                 (u32) ((table->length -
 102                 sizeof(struct acpi_table_header)) / sizeof(u64));
 103         table_entry =
 104                 ACPI_CAST_PTR(u8, table) + sizeof(struct acpi_table_header);
 105         for (i = 0; i < table_count; i++) {
 106                 ACPI_MOVE_64_TO_64(&xsdt_entry_address, table_entry);
 107                 if (!xsdt_entry_address) {
 108                         /* XSDT has NULL entry */
 109                         break;
 110                 }
 111                 table_entry += sizeof(u64);
 112         }
 113         acpi_os_unmap_memory(table, length);
 114
 115         if (i < table_count)
 116                 return AE_NULL_ENTRY;
 117         else
 118                 return AE_OK;
 119 }
 120
 121 /*******************************************************************************
 122  *
 123  * FUNCTION:    acpi_tb_initialize_facs
 124  *
 125  * PARAMETERS:  None
 126  *
 127  * RETURN:      Status
 128  *
 129  * DESCRIPTION: Create a permanent mapping for the FADT and save it in a global
 130  *              for accessing the Global Lock and Firmware Waking Vector
 131  *
 132  ******************************************************************************/
 133
 134 acpi_status acpi_tb_initialize_facs(void)
 135 {
 136         acpi_status status;
 137
 138         /* If Hardware Reduced flag is set, there is no FACS */
 139
 140         if (acpi_gbl_reduced_hardware) {
 141                 acpi_gbl_FACS = NULL;
 142                 return (AE_OK);
 143         }
 144
 145         status = acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
 146                                          ACPI_CAST_INDIRECT_PTR(struct
 147                                                                 acpi_table_header,
 148                                                                 &acpi_gbl_FACS));
 149         return status;
 150 }
 151
 152 /*******************************************************************************
 153  *
 154  * FUNCTION:    acpi_tb_tables_loaded
 155  *
 156  * PARAMETERS:  None
 157  *
 158  * RETURN:      TRUE if required ACPI tables are loaded
 159  *
 160  * DESCRIPTION: Determine if the minimum required ACPI tables are present
 161  *              (FADT, FACS, DSDT)
 162  *
 163  ******************************************************************************/
 164
 165 u8 acpi_tb_tables_loaded(void)
 166 {
 167
 168         if (acpi_gbl_root_table_list.current_table_count >= 3) {
 169                 return (TRUE);
 170         }
 171
 172         return (FALSE);
 173 }
 174
 175 /*******************************************************************************
 176  *
 177  * FUNCTION:    acpi_tb_fix_string
 178  *
 179  * PARAMETERS:  String              - String to be repaired
 180  *              Length              - Maximum length
 181  *
 182  * RETURN:      None
 183  *
 184  * DESCRIPTION: Replace every non-printable or non-ascii byte in the string
 185  *              with a question mark '?'.
 186  *
 187  ******************************************************************************/
 188
 189 static void acpi_tb_fix_string(char *string, acpi_size length)
 190 {
 191
 192         while (length && *string) {
 193                 if (!ACPI_IS_PRINT(*string)) {
 194                         *string = '?';
 195                 }
 196                 string++;
 197                 length--;
 198         }
 199 }
 200
 201 /*******************************************************************************
 202  *
 203  * FUNCTION:    acpi_tb_cleanup_table_header
 204  *
 205  * PARAMETERS:  out_header          - Where the cleaned header is returned
 206  *              Header              - Input ACPI table header
 207  *
 208  * RETURN:      Returns the cleaned header in out_header
 209  *
 210  * DESCRIPTION: Copy the table header and ensure that all "string" fields in
 211  *              the header consist of printable characters.
 212  *
 213  ******************************************************************************/
 214
 215 static void
 216 acpi_tb_cleanup_table_header(struct acpi_table_header *out_header,
 217                              struct acpi_table_header *header)
 218 {
 219
 220         ACPI_MEMCPY(out_header, header, sizeof(struct acpi_table_header));
 221
 222         acpi_tb_fix_string(out_header->signature, ACPI_NAME_SIZE);
 223         acpi_tb_fix_string(out_header->oem_id, ACPI_OEM_ID_SIZE);
 224         acpi_tb_fix_string(out_header->oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
 225         acpi_tb_fix_string(out_header->asl_compiler_id, ACPI_NAME_SIZE);
 226 }
 227
 228 /*******************************************************************************
 229  *
 230  * FUNCTION:    acpi_tb_print_table_header
 231  *
 232  * PARAMETERS:  Address             - Table physical address
 233  *              Header              - Table header
 234  *
 235  * RETURN:      None
 236  *
 237  * DESCRIPTION: Print an ACPI table header. Special cases for FACS and RSDP.
 238  *
 239  ******************************************************************************/
 240
 241 void
 242 acpi_tb_print_table_header(acpi_physical_address address,
 243                            struct acpi_table_header *header)
 244 {
 245         struct acpi_table_header local_header;
 246
 247         /*
 248          * The reason that the Address is cast to a void pointer is so that we
 249          * can use %p which will work properly on both 32-bit and 64-bit hosts.
 250          */
 251         if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_FACS)) {
 252
 253                 /* FACS only has signature and length fields */
 254
 255                 ACPI_INFO((AE_INFO, "%4.4s %p %05X",
 256                            header->signature, ACPI_CAST_PTR(void, address),
 257                            header->length));
 258         } else if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_RSDP)) {
 259
 260                 /* RSDP has no common fields */
 261
 262                 ACPI_MEMCPY(local_header.oem_id,
 263                             ACPI_CAST_PTR(struct acpi_table_rsdp,
 264                                           header)->oem_id, ACPI_OEM_ID_SIZE);
 265                 acpi_tb_fix_string(local_header.oem_id, ACPI_OEM_ID_SIZE);
 266
 267                 ACPI_INFO((AE_INFO, "RSDP %p %05X (v%.2d %6.6s)",
 268                            ACPI_CAST_PTR (void, address),
 269                            (ACPI_CAST_PTR(struct acpi_table_rsdp, header)->
 270                             revision >
 271                             0) ? ACPI_CAST_PTR(struct acpi_table_rsdp,
 272                                                header)->length : 20,
 273                            ACPI_CAST_PTR(struct acpi_table_rsdp,
 274                                          header)->revision,
 275                            local_header.oem_id));
 276         } else {
 277                 /* Standard ACPI table with full common header */
 278
 279                 acpi_tb_cleanup_table_header(&local_header, header);
 280
 281                 ACPI_INFO((AE_INFO,
 282                            "%4.4s %p %05X (v%.2d %6.6s %8.8s %08X %4.4s %08X)",
 283                            local_header.signature, ACPI_CAST_PTR(void, address),
 284                            local_header.length, local_header.revision,
 285                            local_header.oem_id, local_header.oem_table_id,
 286                            local_header.oem_revision,
 287                            local_header.asl_compiler_id,
 288                            local_header.asl_compiler_revision));
 289
 290         }
 291 }
 292
 293 /*******************************************************************************
 294  *
 295  * FUNCTION:    acpi_tb_validate_checksum
 296  *
 297  * PARAMETERS:  Table               - ACPI table to verify
 298  *              Length              - Length of entire table
 299  *
 300  * RETURN:      Status
 301  *
 302  * DESCRIPTION: Verifies that the table checksums to zero. Optionally returns
 303  *              exception on bad checksum.
 304  *
 305  ******************************************************************************/
 306
 307 acpi_status acpi_tb_verify_checksum(struct acpi_table_header *table, u32 length)
 308 {
 309         u8 checksum;
 310
 311         /* Compute the checksum on the table */
 312
 313         checksum = acpi_tb_checksum(ACPI_CAST_PTR(u8, table), length);
 314
 315         /* Checksum ok? (should be zero) */
 316
 317         if (checksum) {
 318                 ACPI_WARNING((AE_INFO,
 319                               "Incorrect checksum in table [%4.4s] - 0x%2.2X, should be 0x%2.2X",
 320                               table->signature, table->checksum,
 321                               (u8) (table->checksum - checksum)));
 322
 323 #if (ACPI_CHECKSUM_ABORT)
 324
 325                 return (AE_BAD_CHECKSUM);
 326 #endif
 327         }
 328
 329         return (AE_OK);
 330 }
 331
 332 /*******************************************************************************
 333  *
 334  * FUNCTION:    acpi_tb_checksum
 335  *
 336  * PARAMETERS:  Buffer          - Pointer to memory region to be checked
 337  *              Length          - Length of this memory region
 338  *
 339  * RETURN:      Checksum (u8)
 340  *
 341  * DESCRIPTION: Calculates circular checksum of memory region.
 342  *
 343  ******************************************************************************/
 344
 345 u8 acpi_tb_checksum(u8 *buffer, u32 length)
 346 {
 347         u8 sum = 0;
 348         u8 *end = buffer + length;
 349
 350         while (buffer < end) {
 351                 sum = (u8) (sum + *(buffer++));
 352         }
 353
 354         return sum;
 355 }
 356
 357 /*******************************************************************************
 358  *
 359  * FUNCTION:    acpi_tb_check_dsdt_header
 360  *
 361  * PARAMETERS:  None
 362  *
 363  * RETURN:      None
 364  *
 365  * DESCRIPTION: Quick compare to check validity of the DSDT. This will detect
 366  *              if the DSDT has been replaced from outside the OS and/or if
 367  *              the DSDT header has been corrupted.
 368  *
 369  ******************************************************************************/
 370
 371 void acpi_tb_check_dsdt_header(void)
 372 {
 373
 374         /* Compare original length and checksum to current values */
 375
 376         if (acpi_gbl_original_dsdt_header.length != acpi_gbl_DSDT->length ||
 377             acpi_gbl_original_dsdt_header.checksum != acpi_gbl_DSDT->checksum) {
 378                 ACPI_ERROR((AE_INFO,
 379                             "The DSDT has been corrupted or replaced - old, new headers below"));
 380                 acpi_tb_print_table_header(0, &acpi_gbl_original_dsdt_header);
 381                 acpi_tb_print_table_header(0, acpi_gbl_DSDT);
 382
 383                 ACPI_ERROR((AE_INFO,
 384                             "Please send DMI info to linux-acpi@vger.kernel.org\n"
 385                             "If system does not work as expected, please boot with acpi=copy_dsdt"));
 386
 387                 /* Disable further error messages */
 388
 389                 acpi_gbl_original_dsdt_header.length = acpi_gbl_DSDT->length;
 390                 acpi_gbl_original_dsdt_header.checksum =
 391                     acpi_gbl_DSDT->checksum;
 392         }
 393 }
 394
 395 /*******************************************************************************
 396  *
 397  * FUNCTION:    acpi_tb_copy_dsdt
 398  *
 399  * PARAMETERS:  table_desc          - Installed table to copy
 400  *
 401  * RETURN:      None
 402  *
 403  * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
 404  *              Some very bad BIOSs are known to either corrupt the DSDT or
 405  *              install a new, bad DSDT. This copy works around the problem.
 406  *
 407  ******************************************************************************/
 408
 409 struct acpi_table_header *acpi_tb_copy_dsdt(u32 table_index)
 410 {
 411         struct acpi_table_header *new_table;
 412         struct acpi_table_desc *table_desc;
 413
 414         table_desc = &acpi_gbl_root_table_list.tables[table_index];
 415
 416         new_table = ACPI_ALLOCATE(table_desc->length);
 417         if (!new_table) {
 418                 ACPI_ERROR((AE_INFO, "Could not copy DSDT of length 0x%X",
 419                             table_desc->length));
 420                 return (NULL);
 421         }
 422
 423         ACPI_MEMCPY(new_table, table_desc->pointer, table_desc->length);
 424         acpi_tb_delete_table(table_desc);
 425         table_desc->pointer = new_table;
 426         table_desc->flags = ACPI_TABLE_ORIGIN_ALLOCATED;
 427
 428         ACPI_INFO((AE_INFO,
 429                    "Forced DSDT copy: length 0x%05X copied locally, original unmapped",
 430                    new_table->length));
 431
 432         return (new_table);
 433 }
 434
 435 /*******************************************************************************
 436  *
 437  * FUNCTION:    acpi_tb_install_table
 438  *
 439  * PARAMETERS:  Address                 - Physical address of DSDT or FACS
 440  *              Signature               - Table signature, NULL if no need to
 441  *                                        match
 442  *              table_index             - Index into root table array
 443  *
 444  * RETURN:      None
 445  *
 446  * DESCRIPTION: Install an ACPI table into the global data structure. The
 447  *              table override mechanism is implemented here to allow the host
 448  *              OS to replace any table before it is installed in the root
 449  *              table array.
 450  *
 451  ******************************************************************************/
 452
 453 void
 454 acpi_tb_install_table(acpi_physical_address address,
 455                       char *signature, u32 table_index)
 456 {
 457         u8 flags;
 458         acpi_status status;
 459         struct acpi_table_header *table_to_install;
 460         struct acpi_table_header *mapped_table;
 461         struct acpi_table_header *override_table = NULL;
 462
 463         if (!address) {
 464                 ACPI_ERROR((AE_INFO,
 465                             "Null physical address for ACPI table [%s]",
 466                             signature));
 467                 return;
 468         }
 469
 470         /* Map just the table header */
 471
 472         mapped_table =
 473             acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 474         if (!mapped_table) {
 475                 return;
 476         }
 477
 478         /* If a particular signature is expected (DSDT/FACS), it must match */
 479
 480         if (signature && !ACPI_COMPARE_NAME(mapped_table->signature, signature)) {
 481                 ACPI_ERROR((AE_INFO,
 482                             "Invalid signature 0x%X for ACPI table, expected [%s]",
 483                             *ACPI_CAST_PTR(u32, mapped_table->signature),
 484                             signature));
 485                 goto unmap_and_exit;
 486         }
 487
 488         /*
 489          * ACPI Table Override:
 490          *
 491          * Before we install the table, let the host OS override it with a new
 492          * one if desired. Any table within the RSDT/XSDT can be replaced,
 493          * including the DSDT which is pointed to by the FADT.
 494          */
 495         status = acpi_os_table_override(mapped_table, &override_table);
 496         if (ACPI_SUCCESS(status) && override_table) {
 497                 ACPI_INFO((AE_INFO,
 498                            "%4.4s @ 0x%p Table override, replaced with:",
 499                            mapped_table->signature, ACPI_CAST_PTR(void,
 500                                                                   address)));
 501
 502                 acpi_gbl_root_table_list.tables[table_index].pointer =
 503                     override_table;
 504                 address = ACPI_PTR_TO_PHYSADDR(override_table);
 505
 506                 table_to_install = override_table;
 507                 flags = ACPI_TABLE_ORIGIN_OVERRIDE;
 508         } else {
 509                 table_to_install = mapped_table;
 510                 flags = ACPI_TABLE_ORIGIN_MAPPED;
 511         }
 512
 513         /* Initialize the table entry */
 514
 515         acpi_gbl_root_table_list.tables[table_index].address = address;
 516         acpi_gbl_root_table_list.tables[table_index].length =
 517             table_to_install->length;
 518         acpi_gbl_root_table_list.tables[table_index].flags = flags;
 519
 520         ACPI_MOVE_32_TO_32(&
 521                            (acpi_gbl_root_table_list.tables[table_index].
 522                             signature), table_to_install->signature);
 523
 524         acpi_tb_print_table_header(address, table_to_install);
 525
 526         if (table_index == ACPI_TABLE_INDEX_DSDT) {
 527
 528                 /* Global integer width is based upon revision of the DSDT */
 529
 530                 acpi_ut_set_integer_width(table_to_install->revision);
 531         }
 532
 533       unmap_and_exit:
 534         acpi_os_unmap_memory(mapped_table, sizeof(struct acpi_table_header));
 535 }
 536
 537 /*******************************************************************************
 538  *
 539  * FUNCTION:    acpi_tb_get_root_table_entry
 540  *
 541  * PARAMETERS:  table_entry         - Pointer to the RSDT/XSDT table entry
 542  *              table_entry_size    - sizeof 32 or 64 (RSDT or XSDT)
 543  *
 544  * RETURN:      Physical address extracted from the root table
 545  *
 546  * DESCRIPTION: Get one root table entry. Handles 32-bit and 64-bit cases on
 547  *              both 32-bit and 64-bit platforms
 548  *
 549  * NOTE:        acpi_physical_address is 32-bit on 32-bit platforms, 64-bit on
 550  *              64-bit platforms.
 551  *
 552  ******************************************************************************/
 553
 554 static acpi_physical_address
 555 acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size)
 556 {
 557         u64 address64;
 558
 559         /*
 560          * Get the table physical address (32-bit for RSDT, 64-bit for XSDT):
 561          * Note: Addresses are 32-bit aligned (not 64) in both RSDT and XSDT
 562          */
 563         if (table_entry_size == sizeof(u32)) {
 564                 /*
 565                  * 32-bit platform, RSDT: Return 32-bit table entry
 566                  * 64-bit platform, RSDT: Expand 32-bit to 64-bit and return
 567                  */
 568                 return ((acpi_physical_address)
 569                         (*ACPI_CAST_PTR(u32, table_entry)));
 570         } else {
 571                 /*
 572                  * 32-bit platform, XSDT: Truncate 64-bit to 32-bit and return
 573                  * 64-bit platform, XSDT: Move (unaligned) 64-bit to local,
 574                  *  return 64-bit
 575                  */
 576                 ACPI_MOVE_64_TO_64(&address64, table_entry);
 577
 578 #if ACPI_MACHINE_WIDTH == 32
 579                 if (address64 > ACPI_UINT32_MAX) {
 580
 581                         /* Will truncate 64-bit address to 32 bits, issue warning */
 582
 583                         ACPI_WARNING((AE_INFO,
 584                                       "64-bit Physical Address in XSDT is too large (0x%8.8X%8.8X),"
 585                                       " truncating",
 586                                       ACPI_FORMAT_UINT64(address64)));
 587                 }
 588 #endif
 589                 return ((acpi_physical_address) (address64));
 590         }
 591 }
 592
 593 /*******************************************************************************
 594  *
 595  * FUNCTION:    acpi_tb_parse_root_table
 596  *
 597  * PARAMETERS:  Rsdp                    - Pointer to the RSDP
 598  *
 599  * RETURN:      Status
 600  *
 601  * DESCRIPTION: This function is called to parse the Root System Description
 602  *              Table (RSDT or XSDT)
 603  *
 604  * NOTE:        Tables are mapped (not copied) for efficiency. The FACS must
 605  *              be mapped and cannot be copied because it contains the actual
 606  *              memory location of the ACPI Global Lock.
 607  *
 608  ******************************************************************************/
 609
 610 acpi_status __init
 611 acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
 612 {
 613         struct acpi_table_rsdp *rsdp;
 614         u32 table_entry_size;
 615         u32 i;
 616         u32 table_count;
 617         struct acpi_table_header *table;
 618         acpi_physical_address address;
 619         acpi_physical_address uninitialized_var(rsdt_address);
 620         u32 length;
 621         u8 *table_entry;
 622         acpi_status status;
 623
 624         ACPI_FUNCTION_TRACE(tb_parse_root_table);
 625
 626         /*
 627          * Map the entire RSDP and extract the address of the RSDT or XSDT
 628          */
 629         rsdp = acpi_os_map_memory(rsdp_address, sizeof(struct acpi_table_rsdp));
 630         if (!rsdp) {
 631                 return_ACPI_STATUS(AE_NO_MEMORY);
 632         }
 633
 634         acpi_tb_print_table_header(rsdp_address,
 635                                    ACPI_CAST_PTR(struct acpi_table_header,
 636                                                  rsdp));
 637
 638         /* Differentiate between RSDT and XSDT root tables */
 639
 640         if (rsdp->revision > 1 && rsdp->xsdt_physical_address
 641                         && !acpi_rsdt_forced) {
 642                 /*
 643                  * Root table is an XSDT (64-bit physical addresses). We must use the
 644                  * XSDT if the revision is > 1 and the XSDT pointer is present, as per
 645                  * the ACPI specification.
 646                  */
 647                 address = (acpi_physical_address) rsdp->xsdt_physical_address;
 648                 table_entry_size = sizeof(u64);
 649                 rsdt_address = (acpi_physical_address)
 650                                         rsdp->rsdt_physical_address;
 651         } else {
 652                 /* Root table is an RSDT (32-bit physical addresses) */
 653
 654                 address = (acpi_physical_address) rsdp->rsdt_physical_address;
 655                 table_entry_size = sizeof(u32);
 656         }
 657
 658         /*
 659          * It is not possible to map more than one entry in some environments,
 660          * so unmap the RSDP here before mapping other tables
 661          */
 662         acpi_os_unmap_memory(rsdp, sizeof(struct acpi_table_rsdp));
 663
 664         if (table_entry_size == sizeof(u64)) {
 665                 if (acpi_tb_check_xsdt(address) == AE_NULL_ENTRY) {
 666                         /* XSDT has NULL entry, RSDT is used */
 667                         address = rsdt_address;
 668                         table_entry_size = sizeof(u32);
 669                         ACPI_WARNING((AE_INFO, "BIOS XSDT has NULL entry, "
 670                                         "using RSDT"));
 671                 }
 672         }
 673         /* Map the RSDT/XSDT table header to get the full table length */
 674
 675         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 676         if (!table) {
 677                 return_ACPI_STATUS(AE_NO_MEMORY);
 678         }
 679
 680         acpi_tb_print_table_header(address, table);
 681
 682         /* Get the length of the full table, verify length and map entire table */
 683
 684         length = table->length;
 685         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
 686
 687         if (length < sizeof(struct acpi_table_header)) {
 688                 ACPI_ERROR((AE_INFO, "Invalid length 0x%X in RSDT/XSDT",
 689                             length));
 690                 return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
 691         }
 692
 693         table = acpi_os_map_memory(address, length);
 694         if (!table) {
 695                 return_ACPI_STATUS(AE_NO_MEMORY);
 696         }
 697
 698         /* Validate the root table checksum */
 699
 700         status = acpi_tb_verify_checksum(table, length);
 701         if (ACPI_FAILURE(status)) {
 702                 acpi_os_unmap_memory(table, length);
 703                 return_ACPI_STATUS(status);
 704         }
 705
 706         /* Calculate the number of tables described in the root table */
 707
 708         table_count = (u32)((table->length - sizeof(struct acpi_table_header)) /
 709                             table_entry_size);
 710         /*
 711          * First two entries in the table array are reserved for the DSDT
 712          * and FACS, which are not actually present in the RSDT/XSDT - they
 713          * come from the FADT
 714          */
 715         table_entry =
 716             ACPI_CAST_PTR(u8, table) + sizeof(struct acpi_table_header);
 717         acpi_gbl_root_table_list.current_table_count = 2;
 718
 719         /*
 720          * Initialize the root table array from the RSDT/XSDT
 721          */
 722         for (i = 0; i < table_count; i++) {
 723                 if (acpi_gbl_root_table_list.current_table_count >=
 724                     acpi_gbl_root_table_list.max_table_count) {
 725
 726                         /* There is no more room in the root table array, attempt resize */
 727
 728                         status = acpi_tb_resize_root_table_list();
 729                         if (ACPI_FAILURE(status)) {
 730                                 ACPI_WARNING((AE_INFO,
 731                                               "Truncating %u table entries!",
 732                                               (unsigned) (table_count -
 733                                                (acpi_gbl_root_table_list.
 734                                                           current_table_count -
 735                                                           2))));
 736                                 break;
 737                         }
 738                 }
 739
 740                 /* Get the table physical address (32-bit for RSDT, 64-bit for XSDT) */
 741
 742                 acpi_gbl_root_table_list.tables[acpi_gbl_root_table_list.
 743                                                 current_table_count].address =
 744                     acpi_tb_get_root_table_entry(table_entry, table_entry_size);
 745
 746                 table_entry += table_entry_size;
 747                 acpi_gbl_root_table_list.current_table_count++;
 748         }
 749
 750         /*
 751          * It is not possible to map more than one entry in some environments,
 752          * so unmap the root table here before mapping other tables
 753          */
 754         acpi_os_unmap_memory(table, length);
 755
 756         /*
 757          * Complete the initialization of the root table array by examining
 758          * the header of each table
 759          */
 760         for (i = 2; i < acpi_gbl_root_table_list.current_table_count; i++) {
 761                 acpi_tb_install_table(acpi_gbl_root_table_list.tables[i].
 762                                       address, NULL, i);
 763
 764                 /* Special case for FADT - get the DSDT and FACS */
 765
 766                 if (ACPI_COMPARE_NAME
 767                     (&acpi_gbl_root_table_list.tables[i].signature,
 768                      ACPI_SIG_FADT)) {
 769                         acpi_tb_parse_fadt(i);
 770                 }
 771         }
 772
 773         return_ACPI_STATUS(AE_OK);
 774 }