drivers/acpi/acpica/tbutils.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbutils   - table utilities
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2011, 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         status = acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
 139                                          ACPI_CAST_INDIRECT_PTR(struct
 140                                                                 acpi_table_header,
 141                                                                 &acpi_gbl_FACS));
 142         return status;
 143 }
 144
 145 /*******************************************************************************
 146  *
 147  * FUNCTION:    acpi_tb_tables_loaded
 148  *
 149  * PARAMETERS:  None
 150  *
 151  * RETURN:      TRUE if required ACPI tables are loaded
 152  *
 153  * DESCRIPTION: Determine if the minimum required ACPI tables are present
 154  *              (FADT, FACS, DSDT)
 155  *
 156  ******************************************************************************/
 157
 158 u8 acpi_tb_tables_loaded(void)
 159 {
 160
 161         if (acpi_gbl_root_table_list.current_table_count >= 3) {
 162                 return (TRUE);
 163         }
 164
 165         return (FALSE);
 166 }
 167
 168 /*******************************************************************************
 169  *
 170  * FUNCTION:    acpi_tb_fix_string
 171  *
 172  * PARAMETERS:  String              - String to be repaired
 173  *              Length              - Maximum length
 174  *
 175  * RETURN:      None
 176  *
 177  * DESCRIPTION: Replace every non-printable or non-ascii byte in the string
 178  *              with a question mark '?'.
 179  *
 180  ******************************************************************************/
 181
 182 static void acpi_tb_fix_string(char *string, acpi_size length)
 183 {
 184
 185         while (length && *string) {
 186                 if (!ACPI_IS_PRINT(*string)) {
 187                         *string = '?';
 188                 }
 189                 string++;
 190                 length--;
 191         }
 192 }
 193
 194 /*******************************************************************************
 195  *
 196  * FUNCTION:    acpi_tb_cleanup_table_header
 197  *
 198  * PARAMETERS:  out_header          - Where the cleaned header is returned
 199  *              Header              - Input ACPI table header
 200  *
 201  * RETURN:      Returns the cleaned header in out_header
 202  *
 203  * DESCRIPTION: Copy the table header and ensure that all "string" fields in
 204  *              the header consist of printable characters.
 205  *
 206  ******************************************************************************/
 207
 208 static void
 209 acpi_tb_cleanup_table_header(struct acpi_table_header *out_header,
 210                              struct acpi_table_header *header)
 211 {
 212
 213         ACPI_MEMCPY(out_header, header, sizeof(struct acpi_table_header));
 214
 215         acpi_tb_fix_string(out_header->signature, ACPI_NAME_SIZE);
 216         acpi_tb_fix_string(out_header->oem_id, ACPI_OEM_ID_SIZE);
 217         acpi_tb_fix_string(out_header->oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
 218         acpi_tb_fix_string(out_header->asl_compiler_id, ACPI_NAME_SIZE);
 219 }
 220
 221 /*******************************************************************************
 222  *
 223  * FUNCTION:    acpi_tb_print_table_header
 224  *
 225  * PARAMETERS:  Address             - Table physical address
 226  *              Header              - Table header
 227  *
 228  * RETURN:      None
 229  *
 230  * DESCRIPTION: Print an ACPI table header. Special cases for FACS and RSDP.
 231  *
 232  ******************************************************************************/
 233
 234 void
 235 acpi_tb_print_table_header(acpi_physical_address address,
 236                            struct acpi_table_header *header)
 237 {
 238         struct acpi_table_header local_header;
 239
 240         /*
 241          * The reason that the Address is cast to a void pointer is so that we
 242          * can use %p which will work properly on both 32-bit and 64-bit hosts.
 243          */
 244         if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_FACS)) {
 245
 246                 /* FACS only has signature and length fields */
 247
 248                 ACPI_INFO((AE_INFO, "%4.4s %p %05X",
 249                            header->signature, ACPI_CAST_PTR(void, address),
 250                            header->length));
 251         } else if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_RSDP)) {
 252
 253                 /* RSDP has no common fields */
 254
 255                 ACPI_MEMCPY(local_header.oem_id,
 256                             ACPI_CAST_PTR(struct acpi_table_rsdp,
 257                                           header)->oem_id, ACPI_OEM_ID_SIZE);
 258                 acpi_tb_fix_string(local_header.oem_id, ACPI_OEM_ID_SIZE);
 259
 260                 ACPI_INFO((AE_INFO, "RSDP %p %05X (v%.2d %6.6s)",
 261                            ACPI_CAST_PTR (void, address),
 262                            (ACPI_CAST_PTR(struct acpi_table_rsdp, header)->
 263                             revision >
 264                             0) ? ACPI_CAST_PTR(struct acpi_table_rsdp,
 265                                                header)->length : 20,
 266                            ACPI_CAST_PTR(struct acpi_table_rsdp,
 267                                          header)->revision,
 268                            local_header.oem_id));
 269         } else {
 270                 /* Standard ACPI table with full common header */
 271
 272                 acpi_tb_cleanup_table_header(&local_header, header);
 273
 274                 ACPI_INFO((AE_INFO,
 275                            "%4.4s %p %05X (v%.2d %6.6s %8.8s %08X %4.4s %08X)",
 276                            local_header.signature, ACPI_CAST_PTR(void, address),
 277                            local_header.length, local_header.revision,
 278                            local_header.oem_id, local_header.oem_table_id,
 279                            local_header.oem_revision,
 280                            local_header.asl_compiler_id,
 281                            local_header.asl_compiler_revision));
 282
 283         }
 284 }
 285
 286 /*******************************************************************************
 287  *
 288  * FUNCTION:    acpi_tb_validate_checksum
 289  *
 290  * PARAMETERS:  Table               - ACPI table to verify
 291  *              Length              - Length of entire table
 292  *
 293  * RETURN:      Status
 294  *
 295  * DESCRIPTION: Verifies that the table checksums to zero. Optionally returns
 296  *              exception on bad checksum.
 297  *
 298  ******************************************************************************/
 299
 300 acpi_status acpi_tb_verify_checksum(struct acpi_table_header *table, u32 length)
 301 {
 302         u8 checksum;
 303
 304         /* Compute the checksum on the table */
 305
 306         checksum = acpi_tb_checksum(ACPI_CAST_PTR(u8, table), length);
 307
 308         /* Checksum ok? (should be zero) */
 309
 310         if (checksum) {
 311                 ACPI_WARNING((AE_INFO,
 312                               "Incorrect checksum in table [%4.4s] - 0x%2.2X, should be 0x%2.2X",
 313                               table->signature, table->checksum,
 314                               (u8) (table->checksum - checksum)));
 315
 316 #if (ACPI_CHECKSUM_ABORT)
 317
 318                 return (AE_BAD_CHECKSUM);
 319 #endif
 320         }
 321
 322         return (AE_OK);
 323 }
 324
 325 /*******************************************************************************
 326  *
 327  * FUNCTION:    acpi_tb_checksum
 328  *
 329  * PARAMETERS:  Buffer          - Pointer to memory region to be checked
 330  *              Length          - Length of this memory region
 331  *
 332  * RETURN:      Checksum (u8)
 333  *
 334  * DESCRIPTION: Calculates circular checksum of memory region.
 335  *
 336  ******************************************************************************/
 337
 338 u8 acpi_tb_checksum(u8 *buffer, u32 length)
 339 {
 340         u8 sum = 0;
 341         u8 *end = buffer + length;
 342
 343         while (buffer < end) {
 344                 sum = (u8) (sum + *(buffer++));
 345         }
 346
 347         return sum;
 348 }
 349
 350 /*******************************************************************************
 351  *
 352  * FUNCTION:    acpi_tb_check_dsdt_header
 353  *
 354  * PARAMETERS:  None
 355  *
 356  * RETURN:      None
 357  *
 358  * DESCRIPTION: Quick compare to check validity of the DSDT. This will detect
 359  *              if the DSDT has been replaced from outside the OS and/or if
 360  *              the DSDT header has been corrupted.
 361  *
 362  ******************************************************************************/
 363
 364 void acpi_tb_check_dsdt_header(void)
 365 {
 366
 367         /* Compare original length and checksum to current values */
 368
 369         if (acpi_gbl_original_dsdt_header.length != acpi_gbl_DSDT->length ||
 370             acpi_gbl_original_dsdt_header.checksum != acpi_gbl_DSDT->checksum) {
 371                 ACPI_ERROR((AE_INFO,
 372                             "The DSDT has been corrupted or replaced - old, new headers below"));
 373                 acpi_tb_print_table_header(0, &acpi_gbl_original_dsdt_header);
 374                 acpi_tb_print_table_header(0, acpi_gbl_DSDT);
 375
 376                 ACPI_ERROR((AE_INFO,
 377                             "Please send DMI info to linux-acpi@vger.kernel.org\n"
 378                             "If system does not work as expected, please boot with acpi=copy_dsdt"));
 379
 380                 /* Disable further error messages */
 381
 382                 acpi_gbl_original_dsdt_header.length = acpi_gbl_DSDT->length;
 383                 acpi_gbl_original_dsdt_header.checksum =
 384                     acpi_gbl_DSDT->checksum;
 385         }
 386 }
 387
 388 /*******************************************************************************
 389  *
 390  * FUNCTION:    acpi_tb_copy_dsdt
 391  *
 392  * PARAMETERS:  table_desc          - Installed table to copy
 393  *
 394  * RETURN:      None
 395  *
 396  * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
 397  *              Some very bad BIOSs are known to either corrupt the DSDT or
 398  *              install a new, bad DSDT. This copy works around the problem.
 399  *
 400  ******************************************************************************/
 401
 402 struct acpi_table_header *acpi_tb_copy_dsdt(u32 table_index)
 403 {
 404         struct acpi_table_header *new_table;
 405         struct acpi_table_desc *table_desc;
 406
 407         table_desc = &acpi_gbl_root_table_list.tables[table_index];
 408
 409         new_table = ACPI_ALLOCATE(table_desc->length);
 410         if (!new_table) {
 411                 ACPI_ERROR((AE_INFO, "Could not copy DSDT of length 0x%X",
 412                             table_desc->length));
 413                 return (NULL);
 414         }
 415
 416         ACPI_MEMCPY(new_table, table_desc->pointer, table_desc->length);
 417         acpi_tb_delete_table(table_desc);
 418         table_desc->pointer = new_table;
 419         table_desc->flags = ACPI_TABLE_ORIGIN_ALLOCATED;
 420
 421         ACPI_INFO((AE_INFO,
 422                    "Forced DSDT copy: length 0x%05X copied locally, original unmapped",
 423                    new_table->length));
 424
 425         return (new_table);
 426 }
 427
 428 /*******************************************************************************
 429  *
 430  * FUNCTION:    acpi_tb_install_table
 431  *
 432  * PARAMETERS:  Address                 - Physical address of DSDT or FACS
 433  *              Signature               - Table signature, NULL if no need to
 434  *                                        match
 435  *              table_index             - Index into root table array
 436  *
 437  * RETURN:      None
 438  *
 439  * DESCRIPTION: Install an ACPI table into the global data structure. The
 440  *              table override mechanism is implemented here to allow the host
 441  *              OS to replace any table before it is installed in the root
 442  *              table array.
 443  *
 444  ******************************************************************************/
 445
 446 void
 447 acpi_tb_install_table(acpi_physical_address address,
 448                       char *signature, u32 table_index)
 449 {
 450         u8 flags;
 451         acpi_status status;
 452         struct acpi_table_header *table_to_install;
 453         struct acpi_table_header *mapped_table;
 454         struct acpi_table_header *override_table = NULL;
 455
 456         if (!address) {
 457                 ACPI_ERROR((AE_INFO,
 458                             "Null physical address for ACPI table [%s]",
 459                             signature));
 460                 return;
 461         }
 462
 463         /* Map just the table header */
 464
 465         mapped_table =
 466             acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 467         if (!mapped_table) {
 468                 return;
 469         }
 470
 471         /* If a particular signature is expected (DSDT/FACS), it must match */
 472
 473         if (signature && !ACPI_COMPARE_NAME(mapped_table->signature, signature)) {
 474                 ACPI_ERROR((AE_INFO,
 475                             "Invalid signature 0x%X for ACPI table, expected [%s]",
 476                             *ACPI_CAST_PTR(u32, mapped_table->signature),
 477                             signature));
 478                 goto unmap_and_exit;
 479         }
 480
 481         /*
 482          * ACPI Table Override:
 483          *
 484          * Before we install the table, let the host OS override it with a new
 485          * one if desired. Any table within the RSDT/XSDT can be replaced,
 486          * including the DSDT which is pointed to by the FADT.
 487          */
 488         status = acpi_os_table_override(mapped_table, &override_table);
 489         if (ACPI_SUCCESS(status) && override_table) {
 490                 ACPI_INFO((AE_INFO,
 491                            "%4.4s @ 0x%p Table override, replaced with:",
 492                            mapped_table->signature, ACPI_CAST_PTR(void,
 493                                                                   address)));
 494
 495                 acpi_gbl_root_table_list.tables[table_index].pointer =
 496                     override_table;
 497                 address = ACPI_PTR_TO_PHYSADDR(override_table);
 498
 499                 table_to_install = override_table;
 500                 flags = ACPI_TABLE_ORIGIN_OVERRIDE;
 501         } else {
 502                 table_to_install = mapped_table;
 503                 flags = ACPI_TABLE_ORIGIN_MAPPED;
 504         }
 505
 506         /* Initialize the table entry */
 507
 508         acpi_gbl_root_table_list.tables[table_index].address = address;
 509         acpi_gbl_root_table_list.tables[table_index].length =
 510             table_to_install->length;
 511         acpi_gbl_root_table_list.tables[table_index].flags = flags;
 512
 513         ACPI_MOVE_32_TO_32(&
 514                            (acpi_gbl_root_table_list.tables[table_index].
 515                             signature), table_to_install->signature);
 516
 517         acpi_tb_print_table_header(address, table_to_install);
 518
 519         if (table_index == ACPI_TABLE_INDEX_DSDT) {
 520
 521                 /* Global integer width is based upon revision of the DSDT */
 522
 523                 acpi_ut_set_integer_width(table_to_install->revision);
 524         }
 525
 526       unmap_and_exit:
 527         acpi_os_unmap_memory(mapped_table, sizeof(struct acpi_table_header));
 528 }
 529
 530 /*******************************************************************************
 531  *
 532  * FUNCTION:    acpi_tb_get_root_table_entry
 533  *
 534  * PARAMETERS:  table_entry         - Pointer to the RSDT/XSDT table entry
 535  *              table_entry_size    - sizeof 32 or 64 (RSDT or XSDT)
 536  *
 537  * RETURN:      Physical address extracted from the root table
 538  *
 539  * DESCRIPTION: Get one root table entry. Handles 32-bit and 64-bit cases on
 540  *              both 32-bit and 64-bit platforms
 541  *
 542  * NOTE:        acpi_physical_address is 32-bit on 32-bit platforms, 64-bit on
 543  *              64-bit platforms.
 544  *
 545  ******************************************************************************/
 546
 547 static acpi_physical_address
 548 acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size)
 549 {
 550         u64 address64;
 551
 552         /*
 553          * Get the table physical address (32-bit for RSDT, 64-bit for XSDT):
 554          * Note: Addresses are 32-bit aligned (not 64) in both RSDT and XSDT
 555          */
 556         if (table_entry_size == sizeof(u32)) {
 557                 /*
 558                  * 32-bit platform, RSDT: Return 32-bit table entry
 559                  * 64-bit platform, RSDT: Expand 32-bit to 64-bit and return
 560                  */
 561                 return ((acpi_physical_address)
 562                         (*ACPI_CAST_PTR(u32, table_entry)));
 563         } else {
 564                 /*
 565                  * 32-bit platform, XSDT: Truncate 64-bit to 32-bit and return
 566                  * 64-bit platform, XSDT: Move (unaligned) 64-bit to local,
 567                  *  return 64-bit
 568                  */
 569                 ACPI_MOVE_64_TO_64(&address64, table_entry);
 570
 571 #if ACPI_MACHINE_WIDTH == 32
 572                 if (address64 > ACPI_UINT32_MAX) {
 573
 574                         /* Will truncate 64-bit address to 32 bits, issue warning */
 575
 576                         ACPI_WARNING((AE_INFO,
 577                                       "64-bit Physical Address in XSDT is too large (0x%8.8X%8.8X),"
 578                                       " truncating",
 579                                       ACPI_FORMAT_UINT64(address64)));
 580                 }
 581 #endif
 582                 return ((acpi_physical_address) (address64));
 583         }
 584 }
 585
 586 /*******************************************************************************
 587  *
 588  * FUNCTION:    acpi_tb_parse_root_table
 589  *
 590  * PARAMETERS:  Rsdp                    - Pointer to the RSDP
 591  *
 592  * RETURN:      Status
 593  *
 594  * DESCRIPTION: This function is called to parse the Root System Description
 595  *              Table (RSDT or XSDT)
 596  *
 597  * NOTE:        Tables are mapped (not copied) for efficiency. The FACS must
 598  *              be mapped and cannot be copied because it contains the actual
 599  *              memory location of the ACPI Global Lock.
 600  *
 601  ******************************************************************************/
 602
 603 acpi_status __init
 604 acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
 605 {
 606         struct acpi_table_rsdp *rsdp;
 607         u32 table_entry_size;
 608         u32 i;
 609         u32 table_count;
 610         struct acpi_table_header *table;
 611         acpi_physical_address address;
 612         acpi_physical_address uninitialized_var(rsdt_address);
 613         u32 length;
 614         u8 *table_entry;
 615         acpi_status status;
 616
 617         ACPI_FUNCTION_TRACE(tb_parse_root_table);
 618
 619         /*
 620          * Map the entire RSDP and extract the address of the RSDT or XSDT
 621          */
 622         rsdp = acpi_os_map_memory(rsdp_address, sizeof(struct acpi_table_rsdp));
 623         if (!rsdp) {
 624                 return_ACPI_STATUS(AE_NO_MEMORY);
 625         }
 626
 627         acpi_tb_print_table_header(rsdp_address,
 628                                    ACPI_CAST_PTR(struct acpi_table_header,
 629                                                  rsdp));
 630
 631         /* Differentiate between RSDT and XSDT root tables */
 632
 633         if (rsdp->revision > 1 && rsdp->xsdt_physical_address
 634                         && !acpi_rsdt_forced) {
 635                 /*
 636                  * Root table is an XSDT (64-bit physical addresses). We must use the
 637                  * XSDT if the revision is > 1 and the XSDT pointer is present, as per
 638                  * the ACPI specification.
 639                  */
 640                 address = (acpi_physical_address) rsdp->xsdt_physical_address;
 641                 table_entry_size = sizeof(u64);
 642                 rsdt_address = (acpi_physical_address)
 643                                         rsdp->rsdt_physical_address;
 644         } else {
 645                 /* Root table is an RSDT (32-bit physical addresses) */
 646
 647                 address = (acpi_physical_address) rsdp->rsdt_physical_address;
 648                 table_entry_size = sizeof(u32);
 649         }
 650
 651         /*
 652          * It is not possible to map more than one entry in some environments,
 653          * so unmap the RSDP here before mapping other tables
 654          */
 655         acpi_os_unmap_memory(rsdp, sizeof(struct acpi_table_rsdp));
 656
 657         if (table_entry_size == sizeof(u64)) {
 658                 if (acpi_tb_check_xsdt(address) == AE_NULL_ENTRY) {
 659                         /* XSDT has NULL entry, RSDT is used */
 660                         address = rsdt_address;
 661                         table_entry_size = sizeof(u32);
 662                         ACPI_WARNING((AE_INFO, "BIOS XSDT has NULL entry, "
 663                                         "using RSDT"));
 664                 }
 665         }
 666         /* Map the RSDT/XSDT table header to get the full table length */
 667
 668         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 669         if (!table) {
 670                 return_ACPI_STATUS(AE_NO_MEMORY);
 671         }
 672
 673         acpi_tb_print_table_header(address, table);
 674
 675         /* Get the length of the full table, verify length and map entire table */
 676
 677         length = table->length;
 678         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
 679
 680         if (length < sizeof(struct acpi_table_header)) {
 681                 ACPI_ERROR((AE_INFO, "Invalid length 0x%X in RSDT/XSDT",
 682                             length));
 683                 return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
 684         }
 685
 686         table = acpi_os_map_memory(address, length);
 687         if (!table) {
 688                 return_ACPI_STATUS(AE_NO_MEMORY);
 689         }
 690
 691         /* Validate the root table checksum */
 692
 693         status = acpi_tb_verify_checksum(table, length);
 694         if (ACPI_FAILURE(status)) {
 695                 acpi_os_unmap_memory(table, length);
 696                 return_ACPI_STATUS(status);
 697         }
 698
 699         /* Calculate the number of tables described in the root table */
 700
 701         table_count = (u32)((table->length - sizeof(struct acpi_table_header)) /
 702                             table_entry_size);
 703         /*
 704          * First two entries in the table array are reserved for the DSDT
 705          * and FACS, which are not actually present in the RSDT/XSDT - they
 706          * come from the FADT
 707          */
 708         table_entry =
 709             ACPI_CAST_PTR(u8, table) + sizeof(struct acpi_table_header);
 710         acpi_gbl_root_table_list.current_table_count = 2;
 711
 712         /*
 713          * Initialize the root table array from the RSDT/XSDT
 714          */
 715         for (i = 0; i < table_count; i++) {
 716                 if (acpi_gbl_root_table_list.current_table_count >=
 717                     acpi_gbl_root_table_list.max_table_count) {
 718
 719                         /* There is no more room in the root table array, attempt resize */
 720
 721                         status = acpi_tb_resize_root_table_list();
 722                         if (ACPI_FAILURE(status)) {
 723                                 ACPI_WARNING((AE_INFO,
 724                                               "Truncating %u table entries!",
 725                                               (unsigned) (table_count -
 726                                                (acpi_gbl_root_table_list.
 727                                                           current_table_count -
 728                                                           2))));
 729                                 break;
 730                         }
 731                 }
 732
 733                 /* Get the table physical address (32-bit for RSDT, 64-bit for XSDT) */
 734
 735                 acpi_gbl_root_table_list.tables[acpi_gbl_root_table_list.
 736                                                 current_table_count].address =
 737                     acpi_tb_get_root_table_entry(table_entry, table_entry_size);
 738
 739                 table_entry += table_entry_size;
 740                 acpi_gbl_root_table_list.current_table_count++;
 741         }
 742
 743         /*
 744          * It is not possible to map more than one entry in some environments,
 745          * so unmap the root table here before mapping other tables
 746          */
 747         acpi_os_unmap_memory(table, length);
 748
 749         /*
 750          * Complete the initialization of the root table array by examining
 751          * the header of each table
 752          */
 753         for (i = 2; i < acpi_gbl_root_table_list.current_table_count; i++) {
 754                 acpi_tb_install_table(acpi_gbl_root_table_list.tables[i].
 755                                       address, NULL, i);
 756
 757                 /* Special case for FADT - get the DSDT and FACS */
 758
 759                 if (ACPI_COMPARE_NAME
 760                     (&acpi_gbl_root_table_list.tables[i].signature,
 761                      ACPI_SIG_FADT)) {
 762                         acpi_tb_parse_fadt(i);
 763                 }
 764         }
 765
 766         return_ACPI_STATUS(AE_OK);
 767 }