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 #if (!ACPI_REDUCED_HARDWARE)
 122 /*******************************************************************************
 123  *
 124  * FUNCTION:    acpi_tb_initialize_facs
 125  *
 126  * PARAMETERS:  None
 127  *
 128  * RETURN:      Status
 129  *
 130  * DESCRIPTION: Create a permanent mapping for the FADT and save it in a global
 131  *              for accessing the Global Lock and Firmware Waking Vector
 132  *
 133  ******************************************************************************/
 134
 135 acpi_status acpi_tb_initialize_facs(void)
 136 {
 137         acpi_status status;
 138
 139         /* If Hardware Reduced flag is set, there is no FACS */
 140
 141         if (acpi_gbl_reduced_hardware) {
 142                 acpi_gbl_FACS = NULL;
 143                 return (AE_OK);
 144         }
 145
 146         status = acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
 147                                          ACPI_CAST_INDIRECT_PTR(struct
 148                                                                 acpi_table_header,
 149                                                                 &acpi_gbl_FACS));
 150         return status;
 151 }
 152 #endif                          /* !ACPI_REDUCED_HARDWARE */
 153
 154 /*******************************************************************************
 155  *
 156  * FUNCTION:    acpi_tb_tables_loaded
 157  *
 158  * PARAMETERS:  None
 159  *
 160  * RETURN:      TRUE if required ACPI tables are loaded
 161  *
 162  * DESCRIPTION: Determine if the minimum required ACPI tables are present
 163  *              (FADT, FACS, DSDT)
 164  *
 165  ******************************************************************************/
 166
 167 u8 acpi_tb_tables_loaded(void)
 168 {
 169
 170         if (acpi_gbl_root_table_list.current_table_count >= 3) {
 171                 return (TRUE);
 172         }
 173
 174         return (FALSE);
 175 }
 176
 177 /*******************************************************************************
 178  *
 179  * FUNCTION:    acpi_tb_fix_string
 180  *
 181  * PARAMETERS:  string              - String to be repaired
 182  *              length              - Maximum length
 183  *
 184  * RETURN:      None
 185  *
 186  * DESCRIPTION: Replace every non-printable or non-ascii byte in the string
 187  *              with a question mark '?'.
 188  *
 189  ******************************************************************************/
 190
 191 static void acpi_tb_fix_string(char *string, acpi_size length)
 192 {
 193
 194         while (length && *string) {
 195                 if (!ACPI_IS_PRINT(*string)) {
 196                         *string = '?';
 197                 }
 198                 string++;
 199                 length--;
 200         }
 201 }
 202
 203 /*******************************************************************************
 204  *
 205  * FUNCTION:    acpi_tb_cleanup_table_header
 206  *
 207  * PARAMETERS:  out_header          - Where the cleaned header is returned
 208  *              header              - Input ACPI table header
 209  *
 210  * RETURN:      Returns the cleaned header in out_header
 211  *
 212  * DESCRIPTION: Copy the table header and ensure that all "string" fields in
 213  *              the header consist of printable characters.
 214  *
 215  ******************************************************************************/
 216
 217 static void
 218 acpi_tb_cleanup_table_header(struct acpi_table_header *out_header,
 219                              struct acpi_table_header *header)
 220 {
 221
 222         ACPI_MEMCPY(out_header, header, sizeof(struct acpi_table_header));
 223
 224         acpi_tb_fix_string(out_header->signature, ACPI_NAME_SIZE);
 225         acpi_tb_fix_string(out_header->oem_id, ACPI_OEM_ID_SIZE);
 226         acpi_tb_fix_string(out_header->oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
 227         acpi_tb_fix_string(out_header->asl_compiler_id, ACPI_NAME_SIZE);
 228 }
 229
 230 /*******************************************************************************
 231  *
 232  * FUNCTION:    acpi_tb_print_table_header
 233  *
 234  * PARAMETERS:  address             - Table physical address
 235  *              header              - Table header
 236  *
 237  * RETURN:      None
 238  *
 239  * DESCRIPTION: Print an ACPI table header. Special cases for FACS and RSDP.
 240  *
 241  ******************************************************************************/
 242
 243 void
 244 acpi_tb_print_table_header(acpi_physical_address address,
 245                            struct acpi_table_header *header)
 246 {
 247         struct acpi_table_header local_header;
 248
 249         /*
 250          * The reason that the Address is cast to a void pointer is so that we
 251          * can use %p which will work properly on both 32-bit and 64-bit hosts.
 252          */
 253         if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_FACS)) {
 254
 255                 /* FACS only has signature and length fields */
 256
 257                 ACPI_INFO((AE_INFO, "%4.4s %p %05X",
 258                            header->signature, ACPI_CAST_PTR(void, address),
 259                            header->length));
 260         } else if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_RSDP)) {
 261
 262                 /* RSDP has no common fields */
 263
 264                 ACPI_MEMCPY(local_header.oem_id,
 265                             ACPI_CAST_PTR(struct acpi_table_rsdp,
 266                                           header)->oem_id, ACPI_OEM_ID_SIZE);
 267                 acpi_tb_fix_string(local_header.oem_id, ACPI_OEM_ID_SIZE);
 268
 269                 ACPI_INFO((AE_INFO, "RSDP %p %05X (v%.2d %6.6s)",
 270                            ACPI_CAST_PTR (void, address),
 271                            (ACPI_CAST_PTR(struct acpi_table_rsdp, header)->
 272                             revision >
 273                             0) ? ACPI_CAST_PTR(struct acpi_table_rsdp,
 274                                                header)->length : 20,
 275                            ACPI_CAST_PTR(struct acpi_table_rsdp,
 276                                          header)->revision,
 277                            local_header.oem_id));
 278         } else {
 279                 /* Standard ACPI table with full common header */
 280
 281                 acpi_tb_cleanup_table_header(&local_header, header);
 282
 283                 ACPI_INFO((AE_INFO,
 284                            "%4.4s %p %05X (v%.2d %6.6s %8.8s %08X %4.4s %08X)",
 285                            local_header.signature, ACPI_CAST_PTR(void, address),
 286                            local_header.length, local_header.revision,
 287                            local_header.oem_id, local_header.oem_table_id,
 288                            local_header.oem_revision,
 289                            local_header.asl_compiler_id,
 290                            local_header.asl_compiler_revision));
 291
 292         }
 293 }
 294
 295 /*******************************************************************************
 296  *
 297  * FUNCTION:    acpi_tb_validate_checksum
 298  *
 299  * PARAMETERS:  table               - ACPI table to verify
 300  *              length              - Length of entire table
 301  *
 302  * RETURN:      Status
 303  *
 304  * DESCRIPTION: Verifies that the table checksums to zero. Optionally returns
 305  *              exception on bad checksum.
 306  *
 307  ******************************************************************************/
 308
 309 acpi_status acpi_tb_verify_checksum(struct acpi_table_header *table, u32 length)
 310 {
 311         u8 checksum;
 312
 313         /* Compute the checksum on the table */
 314
 315         checksum = acpi_tb_checksum(ACPI_CAST_PTR(u8, table), length);
 316
 317         /* Checksum ok? (should be zero) */
 318
 319         if (checksum) {
 320                 ACPI_BIOS_WARNING((AE_INFO,
 321                                    "Incorrect checksum in table [%4.4s] - 0x%2.2X, "
 322                                    "should be 0x%2.2X",
 323                                    table->signature, table->checksum,
 324                                    (u8)(table->checksum - checksum)));
 325
 326 #if (ACPI_CHECKSUM_ABORT)
 327
 328                 return (AE_BAD_CHECKSUM);
 329 #endif
 330         }
 331
 332         return (AE_OK);
 333 }
 334
 335 /*******************************************************************************
 336  *
 337  * FUNCTION:    acpi_tb_checksum
 338  *
 339  * PARAMETERS:  buffer          - Pointer to memory region to be checked
 340  *              length          - Length of this memory region
 341  *
 342  * RETURN:      Checksum (u8)
 343  *
 344  * DESCRIPTION: Calculates circular checksum of memory region.
 345  *
 346  ******************************************************************************/
 347
 348 u8 acpi_tb_checksum(u8 *buffer, u32 length)
 349 {
 350         u8 sum = 0;
 351         u8 *end = buffer + length;
 352
 353         while (buffer < end) {
 354                 sum = (u8) (sum + *(buffer++));
 355         }
 356
 357         return sum;
 358 }
 359
 360 /*******************************************************************************
 361  *
 362  * FUNCTION:    acpi_tb_check_dsdt_header
 363  *
 364  * PARAMETERS:  None
 365  *
 366  * RETURN:      None
 367  *
 368  * DESCRIPTION: Quick compare to check validity of the DSDT. This will detect
 369  *              if the DSDT has been replaced from outside the OS and/or if
 370  *              the DSDT header has been corrupted.
 371  *
 372  ******************************************************************************/
 373
 374 void acpi_tb_check_dsdt_header(void)
 375 {
 376
 377         /* Compare original length and checksum to current values */
 378
 379         if (acpi_gbl_original_dsdt_header.length != acpi_gbl_DSDT->length ||
 380             acpi_gbl_original_dsdt_header.checksum != acpi_gbl_DSDT->checksum) {
 381                 ACPI_BIOS_ERROR((AE_INFO,
 382                                  "The DSDT has been corrupted or replaced - "
 383                                  "old, new headers below"));
 384                 acpi_tb_print_table_header(0, &acpi_gbl_original_dsdt_header);
 385                 acpi_tb_print_table_header(0, acpi_gbl_DSDT);
 386
 387                 ACPI_ERROR((AE_INFO,
 388                             "Please send DMI info to linux-acpi@vger.kernel.org\n"
 389                             "If system does not work as expected, please boot with acpi=copy_dsdt"));
 390
 391                 /* Disable further error messages */
 392
 393                 acpi_gbl_original_dsdt_header.length = acpi_gbl_DSDT->length;
 394                 acpi_gbl_original_dsdt_header.checksum =
 395                     acpi_gbl_DSDT->checksum;
 396         }
 397 }
 398
 399 /*******************************************************************************
 400  *
 401  * FUNCTION:    acpi_tb_copy_dsdt
 402  *
 403  * PARAMETERS:  table_desc          - Installed table to copy
 404  *
 405  * RETURN:      None
 406  *
 407  * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
 408  *              Some very bad BIOSs are known to either corrupt the DSDT or
 409  *              install a new, bad DSDT. This copy works around the problem.
 410  *
 411  ******************************************************************************/
 412
 413 struct acpi_table_header *acpi_tb_copy_dsdt(u32 table_index)
 414 {
 415         struct acpi_table_header *new_table;
 416         struct acpi_table_desc *table_desc;
 417
 418         table_desc = &acpi_gbl_root_table_list.tables[table_index];
 419
 420         new_table = ACPI_ALLOCATE(table_desc->length);
 421         if (!new_table) {
 422                 ACPI_ERROR((AE_INFO, "Could not copy DSDT of length 0x%X",
 423                             table_desc->length));
 424                 return (NULL);
 425         }
 426
 427         ACPI_MEMCPY(new_table, table_desc->pointer, table_desc->length);
 428         acpi_tb_delete_table(table_desc);
 429         table_desc->pointer = new_table;
 430         table_desc->flags = ACPI_TABLE_ORIGIN_ALLOCATED;
 431
 432         ACPI_INFO((AE_INFO,
 433                    "Forced DSDT copy: length 0x%05X copied locally, original unmapped",
 434                    new_table->length));
 435
 436         return (new_table);
 437 }
 438
 439 /*******************************************************************************
 440  *
 441  * FUNCTION:    acpi_tb_install_table
 442  *
 443  * PARAMETERS:  address                 - Physical address of DSDT or FACS
 444  *              signature               - Table signature, NULL if no need to
 445  *                                        match
 446  *              table_index             - Index into root table array
 447  *
 448  * RETURN:      None
 449  *
 450  * DESCRIPTION: Install an ACPI table into the global data structure. The
 451  *              table override mechanism is called to allow the host
 452  *              OS to replace any table before it is installed in the root
 453  *              table array.
 454  *
 455  ******************************************************************************/
 456
 457 void
 458 acpi_tb_install_table(acpi_physical_address address,
 459                       char *signature, u32 table_index)
 460 {
 461         struct acpi_table_header *table;
 462         struct acpi_table_header *final_table;
 463         struct acpi_table_desc *table_desc;
 464
 465         if (!address) {
 466                 ACPI_ERROR((AE_INFO,
 467                             "Null physical address for ACPI table [%s]",
 468                             signature));
 469                 return;
 470         }
 471
 472         /* Map just the table header */
 473
 474         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 475         if (!table) {
 476                 ACPI_ERROR((AE_INFO,
 477                             "Could not map memory for table [%s] at %p",
 478                             signature, ACPI_CAST_PTR(void, address)));
 479                 return;
 480         }
 481
 482         /* If a particular signature is expected (DSDT/FACS), it must match */
 483
 484         if (signature && !ACPI_COMPARE_NAME(table->signature, signature)) {
 485                 ACPI_BIOS_ERROR((AE_INFO,
 486                                  "Invalid signature 0x%X for ACPI table, expected [%s]",
 487                                  *ACPI_CAST_PTR(u32, table->signature),
 488                                  signature));
 489                 goto unmap_and_exit;
 490         }
 491
 492         /*
 493          * Initialize the table entry. Set the pointer to NULL, since the
 494          * table is not fully mapped at this time.
 495          */
 496         table_desc = &acpi_gbl_root_table_list.tables[table_index];
 497
 498         table_desc->address = address;
 499         table_desc->pointer = NULL;
 500         table_desc->length = table->length;
 501         table_desc->flags = ACPI_TABLE_ORIGIN_MAPPED;
 502         ACPI_MOVE_32_TO_32(table_desc->signature.ascii, table->signature);
 503
 504         /*
 505          * ACPI Table Override:
 506          *
 507          * Before we install the table, let the host OS override it with a new
 508          * one if desired. Any table within the RSDT/XSDT can be replaced,
 509          * including the DSDT which is pointed to by the FADT.
 510          *
 511          * NOTE: If the table is overridden, then final_table will contain a
 512          * mapped pointer to the full new table. If the table is not overridden,
 513          * or if there has been a physical override, then the table will be
 514          * fully mapped later (in verify table). In any case, we must
 515          * unmap the header that was mapped above.
 516          */
 517         final_table = acpi_tb_table_override(table, table_desc);
 518         if (!final_table) {
 519                 final_table = table;    /* There was no override */
 520         }
 521
 522         acpi_tb_print_table_header(table_desc->address, final_table);
 523
 524         /* Set the global integer width (based upon revision of the DSDT) */
 525
 526         if (table_index == ACPI_TABLE_INDEX_DSDT) {
 527                 acpi_ut_set_integer_width(final_table->revision);
 528         }
 529
 530         /*
 531          * If we have a physical override during this early loading of the ACPI
 532          * tables, unmap the table for now. It will be mapped again later when
 533          * it is actually used. This supports very early loading of ACPI tables,
 534          * before virtual memory is fully initialized and running within the
 535          * host OS. Note: A logical override has the ACPI_TABLE_ORIGIN_OVERRIDE
 536          * flag set and will not be deleted below.
 537          */
 538         if (final_table != table) {
 539                 acpi_tb_delete_table(table_desc);
 540         }
 541
 542       unmap_and_exit:
 543
 544         /* Always unmap the table header that we mapped above */
 545
 546         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
 547 }
 548
 549 /*******************************************************************************
 550  *
 551  * FUNCTION:    acpi_tb_get_root_table_entry
 552  *
 553  * PARAMETERS:  table_entry         - Pointer to the RSDT/XSDT table entry
 554  *              table_entry_size    - sizeof 32 or 64 (RSDT or XSDT)
 555  *
 556  * RETURN:      Physical address extracted from the root table
 557  *
 558  * DESCRIPTION: Get one root table entry. Handles 32-bit and 64-bit cases on
 559  *              both 32-bit and 64-bit platforms
 560  *
 561  * NOTE:        acpi_physical_address is 32-bit on 32-bit platforms, 64-bit on
 562  *              64-bit platforms.
 563  *
 564  ******************************************************************************/
 565
 566 static acpi_physical_address
 567 acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size)
 568 {
 569         u64 address64;
 570
 571         /*
 572          * Get the table physical address (32-bit for RSDT, 64-bit for XSDT):
 573          * Note: Addresses are 32-bit aligned (not 64) in both RSDT and XSDT
 574          */
 575         if (table_entry_size == sizeof(u32)) {
 576                 /*
 577                  * 32-bit platform, RSDT: Return 32-bit table entry
 578                  * 64-bit platform, RSDT: Expand 32-bit to 64-bit and return
 579                  */
 580                 return ((acpi_physical_address)
 581                         (*ACPI_CAST_PTR(u32, table_entry)));
 582         } else {
 583                 /*
 584                  * 32-bit platform, XSDT: Truncate 64-bit to 32-bit and return
 585                  * 64-bit platform, XSDT: Move (unaligned) 64-bit to local,
 586                  *  return 64-bit
 587                  */
 588                 ACPI_MOVE_64_TO_64(&address64, table_entry);
 589
 590 #if ACPI_MACHINE_WIDTH == 32
 591                 if (address64 > ACPI_UINT32_MAX) {
 592
 593                         /* Will truncate 64-bit address to 32 bits, issue warning */
 594
 595                         ACPI_BIOS_WARNING((AE_INFO,
 596                                            "64-bit Physical Address in XSDT is too large (0x%8.8X%8.8X),"
 597                                            " truncating",
 598                                            ACPI_FORMAT_UINT64(address64)));
 599                 }
 600 #endif
 601                 return ((acpi_physical_address) (address64));
 602         }
 603 }
 604
 605 /*******************************************************************************
 606  *
 607  * FUNCTION:    acpi_tb_parse_root_table
 608  *
 609  * PARAMETERS:  rsdp                    - Pointer to the RSDP
 610  *
 611  * RETURN:      Status
 612  *
 613  * DESCRIPTION: This function is called to parse the Root System Description
 614  *              Table (RSDT or XSDT)
 615  *
 616  * NOTE:        Tables are mapped (not copied) for efficiency. The FACS must
 617  *              be mapped and cannot be copied because it contains the actual
 618  *              memory location of the ACPI Global Lock.
 619  *
 620  ******************************************************************************/
 621
 622 acpi_status __init
 623 acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
 624 {
 625         struct acpi_table_rsdp *rsdp;
 626         u32 table_entry_size;
 627         u32 i;
 628         u32 table_count;
 629         struct acpi_table_header *table;
 630         acpi_physical_address address;
 631         acpi_physical_address uninitialized_var(rsdt_address);
 632         u32 length;
 633         u8 *table_entry;
 634         acpi_status status;
 635
 636         ACPI_FUNCTION_TRACE(tb_parse_root_table);
 637
 638         /*
 639          * Map the entire RSDP and extract the address of the RSDT or XSDT
 640          */
 641         rsdp = acpi_os_map_memory(rsdp_address, sizeof(struct acpi_table_rsdp));
 642         if (!rsdp) {
 643                 return_ACPI_STATUS(AE_NO_MEMORY);
 644         }
 645
 646         acpi_tb_print_table_header(rsdp_address,
 647                                    ACPI_CAST_PTR(struct acpi_table_header,
 648                                                  rsdp));
 649
 650         /* Differentiate between RSDT and XSDT root tables */
 651
 652         if (rsdp->revision > 1 && rsdp->xsdt_physical_address
 653                         && !acpi_rsdt_forced) {
 654                 /*
 655                  * Root table is an XSDT (64-bit physical addresses). We must use the
 656                  * XSDT if the revision is > 1 and the XSDT pointer is present, as per
 657                  * the ACPI specification.
 658                  */
 659                 address = (acpi_physical_address) rsdp->xsdt_physical_address;
 660                 table_entry_size = sizeof(u64);
 661                 rsdt_address = (acpi_physical_address)
 662                                         rsdp->rsdt_physical_address;
 663         } else {
 664                 /* Root table is an RSDT (32-bit physical addresses) */
 665
 666                 address = (acpi_physical_address) rsdp->rsdt_physical_address;
 667                 table_entry_size = sizeof(u32);
 668         }
 669
 670         /*
 671          * It is not possible to map more than one entry in some environments,
 672          * so unmap the RSDP here before mapping other tables
 673          */
 674         acpi_os_unmap_memory(rsdp, sizeof(struct acpi_table_rsdp));
 675
 676         if (table_entry_size == sizeof(u64)) {
 677                 if (acpi_tb_check_xsdt(address) == AE_NULL_ENTRY) {
 678                         /* XSDT has NULL entry, RSDT is used */
 679                         address = rsdt_address;
 680                         table_entry_size = sizeof(u32);
 681                         ACPI_WARNING((AE_INFO, "BIOS XSDT has NULL entry, "
 682                                         "using RSDT"));
 683                 }
 684         }
 685         /* Map the RSDT/XSDT table header to get the full table length */
 686
 687         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 688         if (!table) {
 689                 return_ACPI_STATUS(AE_NO_MEMORY);
 690         }
 691
 692         acpi_tb_print_table_header(address, table);
 693
 694         /* Get the length of the full table, verify length and map entire table */
 695
 696         length = table->length;
 697         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
 698
 699         if (length < sizeof(struct acpi_table_header)) {
 700                 ACPI_BIOS_ERROR((AE_INFO,
 701                                  "Invalid table length 0x%X in RSDT/XSDT",
 702                                  length));
 703                 return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
 704         }
 705
 706         table = acpi_os_map_memory(address, length);
 707         if (!table) {
 708                 return_ACPI_STATUS(AE_NO_MEMORY);
 709         }
 710
 711         /* Validate the root table checksum */
 712
 713         status = acpi_tb_verify_checksum(table, length);
 714         if (ACPI_FAILURE(status)) {
 715                 acpi_os_unmap_memory(table, length);
 716                 return_ACPI_STATUS(status);
 717         }
 718
 719         /* Calculate the number of tables described in the root table */
 720
 721         table_count = (u32)((table->length - sizeof(struct acpi_table_header)) /
 722                             table_entry_size);
 723         /*
 724          * First two entries in the table array are reserved for the DSDT
 725          * and FACS, which are not actually present in the RSDT/XSDT - they
 726          * come from the FADT
 727          */
 728         table_entry =
 729             ACPI_CAST_PTR(u8, table) + sizeof(struct acpi_table_header);
 730         acpi_gbl_root_table_list.current_table_count = 2;
 731
 732         /*
 733          * Initialize the root table array from the RSDT/XSDT
 734          */
 735         for (i = 0; i < table_count; i++) {
 736                 if (acpi_gbl_root_table_list.current_table_count >=
 737                     acpi_gbl_root_table_list.max_table_count) {
 738
 739                         /* There is no more room in the root table array, attempt resize */
 740
 741                         status = acpi_tb_resize_root_table_list();
 742                         if (ACPI_FAILURE(status)) {
 743                                 ACPI_WARNING((AE_INFO,
 744                                               "Truncating %u table entries!",
 745                                               (unsigned) (table_count -
 746                                                (acpi_gbl_root_table_list.
 747                                                           current_table_count -
 748                                                           2))));
 749                                 break;
 750                         }
 751                 }
 752
 753                 /* Get the table physical address (32-bit for RSDT, 64-bit for XSDT) */
 754
 755                 acpi_gbl_root_table_list.tables[acpi_gbl_root_table_list.
 756                                                 current_table_count].address =
 757                     acpi_tb_get_root_table_entry(table_entry, table_entry_size);
 758
 759                 table_entry += table_entry_size;
 760                 acpi_gbl_root_table_list.current_table_count++;
 761         }
 762
 763         /*
 764          * It is not possible to map more than one entry in some environments,
 765          * so unmap the root table here before mapping other tables
 766          */
 767         acpi_os_unmap_memory(table, length);
 768
 769         /*
 770          * Complete the initialization of the root table array by examining
 771          * the header of each table
 772          */
 773         for (i = 2; i < acpi_gbl_root_table_list.current_table_count; i++) {
 774                 acpi_tb_install_table(acpi_gbl_root_table_list.tables[i].
 775                                       address, NULL, i);
 776
 777                 /* Special case for FADT - get the DSDT and FACS */
 778
 779                 if (ACPI_COMPARE_NAME
 780                     (&acpi_gbl_root_table_list.tables[i].signature,
 781                      ACPI_SIG_FADT)) {
 782                         acpi_tb_parse_fadt(i);
 783                 }
 784         }
 785
 786         return_ACPI_STATUS(AE_OK);
 787 }