drivers/acpi/tables/tbutils.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbutils - Table manipulation utilities
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2006, R. Byron Moore
   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 <acpi/actables.h>
  46
  47 #define _COMPONENT          ACPI_TABLES
  48 ACPI_MODULE_NAME("tbutils")
  49
  50 /* Local prototypes */
  51 #ifdef ACPI_OBSOLETE_FUNCTIONS
  52 acpi_status
  53 acpi_tb_handle_to_object(u16 table_id, struct acpi_table_desc **table_desc);
  54 #endif
  55
  56 /*******************************************************************************
  57  *
  58  * FUNCTION:    acpi_tb_is_table_installed
  59  *
  60  * PARAMETERS:  new_table_desc      - Descriptor for new table being installed
  61  *
  62  * RETURN:      Status - AE_ALREADY_EXISTS if the table is already installed
  63  *
  64  * DESCRIPTION: Determine if an ACPI table is already installed
  65  *
  66  * MUTEX:       Table data structures should be locked
  67  *
  68  ******************************************************************************/
  69
  70 acpi_status acpi_tb_is_table_installed(struct acpi_table_desc *new_table_desc)
  71 {
  72         struct acpi_table_desc *table_desc;
  73
  74         ACPI_FUNCTION_TRACE(tb_is_table_installed);
  75
  76         /* Get the list descriptor and first table descriptor */
  77
  78         table_desc = acpi_gbl_table_lists[new_table_desc->type].next;
  79
  80         /* Examine all installed tables of this type */
  81
  82         while (table_desc) {
  83                 /*
  84                  * If the table lengths match, perform a full bytewise compare. This
  85                  * means that we will allow tables with duplicate oem_table_id(s), as
  86                  * long as the tables are different in some way.
  87                  *
  88                  * Checking if the table has been loaded into the namespace means that
  89                  * we don't check for duplicate tables during the initial installation
  90                  * of tables within the RSDT/XSDT.
  91                  */
  92                 if ((table_desc->loaded_into_namespace) &&
  93                     (table_desc->pointer->length ==
  94                      new_table_desc->pointer->length)
  95                     &&
  96                     (!ACPI_MEMCMP
  97                      (table_desc->pointer, new_table_desc->pointer,
  98                       new_table_desc->pointer->length))) {
  99
 100                         /* Match: this table is already installed */
 101
 102                         ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
 103                                           "Table [%4.4s] already installed: Rev %X OemTableId [%8.8s]\n",
 104                                           new_table_desc->pointer->signature,
 105                                           new_table_desc->pointer->revision,
 106                                           new_table_desc->pointer->
 107                                           oem_table_id));
 108
 109                         new_table_desc->owner_id = table_desc->owner_id;
 110                         new_table_desc->installed_desc = table_desc;
 111
 112                         return_ACPI_STATUS(AE_ALREADY_EXISTS);
 113                 }
 114
 115                 /* Get next table on the list */
 116
 117                 table_desc = table_desc->next;
 118         }
 119
 120         return_ACPI_STATUS(AE_OK);
 121 }
 122
 123 /*******************************************************************************
 124  *
 125  * FUNCTION:    acpi_tb_validate_table_header
 126  *
 127  * PARAMETERS:  table_header        - Logical pointer to the table
 128  *
 129  * RETURN:      Status
 130  *
 131  * DESCRIPTION: Check an ACPI table header for validity
 132  *
 133  * NOTE:  Table pointers are validated as follows:
 134  *          1) Table pointer must point to valid physical memory
 135  *          2) Signature must be 4 ASCII chars, even if we don't recognize the
 136  *             name
 137  *          3) Table must be readable for length specified in the header
 138  *          4) Table checksum must be valid (with the exception of the FACS
 139  *              which has no checksum because it contains variable fields)
 140  *
 141  ******************************************************************************/
 142
 143 acpi_status
 144 acpi_tb_validate_table_header(struct acpi_table_header *table_header)
 145 {
 146         acpi_name signature;
 147
 148         ACPI_FUNCTION_ENTRY();
 149
 150         /* Verify that this is a valid address */
 151
 152         if (!acpi_os_readable(table_header, sizeof(struct acpi_table_header))) {
 153                 ACPI_ERROR((AE_INFO,
 154                             "Cannot read table header at %p", table_header));
 155
 156                 return (AE_BAD_ADDRESS);
 157         }
 158
 159         /* Ensure that the signature is 4 ASCII characters */
 160
 161         ACPI_MOVE_32_TO_32(&signature, table_header->signature);
 162         if (!acpi_ut_valid_acpi_name(signature)) {
 163                 ACPI_ERROR((AE_INFO,
 164                             "Table signature at %p [%p] has invalid characters",
 165                             table_header, &signature));
 166
 167                 ACPI_WARNING((AE_INFO, "Invalid table signature found: [%4.4s]",
 168                               ACPI_CAST_PTR(char, &signature)));
 169
 170                 ACPI_DUMP_BUFFER(table_header,
 171                                  sizeof(struct acpi_table_header));
 172                 return (AE_BAD_SIGNATURE);
 173         }
 174
 175         /* Validate the table length */
 176
 177         if (table_header->length < sizeof(struct acpi_table_header)) {
 178                 ACPI_ERROR((AE_INFO,
 179                             "Invalid length in table header %p name %4.4s",
 180                             table_header, (char *)&signature));
 181
 182                 ACPI_WARNING((AE_INFO,
 183                               "Invalid table header length (0x%X) found",
 184                               (u32) table_header->length));
 185
 186                 ACPI_DUMP_BUFFER(table_header,
 187                                  sizeof(struct acpi_table_header));
 188                 return (AE_BAD_HEADER);
 189         }
 190
 191         return (AE_OK);
 192 }
 193
 194 /*******************************************************************************
 195  *
 196  * FUNCTION:    acpi_tb_sum_table
 197  *
 198  * PARAMETERS:  Buffer              - Buffer to sum
 199  *              Length              - Size of the buffer
 200  *
 201  * RETURN:      8 bit sum of buffer
 202  *
 203  * DESCRIPTION: Computes an 8 bit sum of the buffer(length) and returns it.
 204  *
 205  ******************************************************************************/
 206
 207 u8 acpi_tb_sum_table(void *buffer, u32 length)
 208 {
 209         acpi_native_uint i;
 210         u8 sum = 0;
 211
 212         if (!buffer || !length) {
 213                 return (0);
 214         }
 215
 216         for (i = 0; i < length; i++) {
 217                 sum = (u8) (sum + ((u8 *) buffer)[i]);
 218         }
 219         return (sum);
 220 }
 221
 222 /*******************************************************************************
 223  *
 224  * FUNCTION:    acpi_tb_generate_checksum
 225  *
 226  * PARAMETERS:  Table               - Pointer to a valid ACPI table (with a
 227  *                                    standard ACPI header)
 228  *
 229  * RETURN:      8 bit checksum of buffer
 230  *
 231  * DESCRIPTION: Computes an 8 bit checksum of the table.
 232  *
 233  ******************************************************************************/
 234
 235 u8 acpi_tb_generate_checksum(struct acpi_table_header * table)
 236 {
 237         u8 checksum;
 238
 239         /* Sum the entire table as-is */
 240
 241         checksum = acpi_tb_sum_table(table, table->length);
 242
 243         /* Subtract off the existing checksum value in the table */
 244
 245         checksum = (u8) (checksum - table->checksum);
 246
 247         /* Compute the final checksum */
 248
 249         checksum = (u8) (0 - checksum);
 250         return (checksum);
 251 }
 252
 253 /*******************************************************************************
 254  *
 255  * FUNCTION:    acpi_tb_set_checksum
 256  *
 257  * PARAMETERS:  Table               - Pointer to a valid ACPI table (with a
 258  *                                    standard ACPI header)
 259  *
 260  * RETURN:      None. Sets the table checksum field
 261  *
 262  * DESCRIPTION: Computes an 8 bit checksum of the table and inserts the
 263  *              checksum into the table header.
 264  *
 265  ******************************************************************************/
 266
 267 void acpi_tb_set_checksum(struct acpi_table_header *table)
 268 {
 269
 270         table->checksum = acpi_tb_generate_checksum(table);
 271 }
 272
 273 /*******************************************************************************
 274  *
 275  * FUNCTION:    acpi_tb_verify_table_checksum
 276  *
 277  * PARAMETERS:  *table_header           - ACPI table to verify
 278  *
 279  * RETURN:      8 bit checksum of table
 280  *
 281  * DESCRIPTION: Generates an 8 bit checksum of table and returns and compares
 282  *              it to the existing checksum value.
 283  *
 284  ******************************************************************************/
 285
 286 acpi_status
 287 acpi_tb_verify_table_checksum(struct acpi_table_header *table_header)
 288 {
 289         u8 checksum;
 290
 291         ACPI_FUNCTION_TRACE(tb_verify_table_checksum);
 292
 293         /* Compute the checksum on the table */
 294
 295         checksum = acpi_tb_generate_checksum(table_header);
 296
 297         /* Checksum ok? */
 298
 299         if (checksum == table_header->checksum) {
 300                 return_ACPI_STATUS(AE_OK);
 301         }
 302
 303         ACPI_WARNING((AE_INFO,
 304                       "Incorrect checksum in table [%4.4s] - is %2.2X, should be %2.2X",
 305                       table_header->signature, table_header->checksum,
 306                       checksum));
 307
 308         return_ACPI_STATUS(AE_BAD_CHECKSUM);
 309 }
 310
 311 #ifdef ACPI_OBSOLETE_FUNCTIONS
 312 /*******************************************************************************
 313  *
 314  * FUNCTION:    acpi_tb_handle_to_object
 315  *
 316  * PARAMETERS:  table_id            - Id for which the function is searching
 317  *              table_desc          - Pointer to return the matching table
 318  *                                      descriptor.
 319  *
 320  * RETURN:      Search the tables to find one with a matching table_id and
 321  *              return a pointer to that table descriptor.
 322  *
 323  ******************************************************************************/
 324
 325 acpi_status
 326 acpi_tb_handle_to_object(u16 table_id,
 327                          struct acpi_table_desc **return_table_desc)
 328 {
 329         u32 i;
 330         struct acpi_table_desc *table_desc;
 331
 332         ACPI_FUNCTION_NAME(tb_handle_to_object);
 333
 334         for (i = 0; i < ACPI_TABLE_MAX; i++) {
 335                 table_desc = acpi_gbl_table_lists[i].next;
 336                 while (table_desc) {
 337                         if (table_desc->table_id == table_id) {
 338                                 *return_table_desc = table_desc;
 339                                 return (AE_OK);
 340                         }
 341
 342                         table_desc = table_desc->next;
 343                 }
 344         }
 345
 346         ACPI_ERROR((AE_INFO, "TableId=%X does not exist", table_id));
 347         return (AE_BAD_PARAMETER);
 348 }
 349 #endif