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, "Invalid table signature 0x%8.8X",
 164                             signature));
 165
 166                 ACPI_DUMP_BUFFER(table_header,
 167                                  sizeof(struct acpi_table_header));
 168                 return (AE_BAD_SIGNATURE);
 169         }
 170
 171         /* Validate the table length */
 172
 173         if (table_header->length < sizeof(struct acpi_table_header)) {
 174                 ACPI_ERROR((AE_INFO,
 175                             "Invalid length 0x%X in table with signature %4.4s",
 176                             (u32) table_header->length,
 177                             ACPI_CAST_PTR(char, &signature)));
 178
 179                 ACPI_DUMP_BUFFER(table_header,
 180                                  sizeof(struct acpi_table_header));
 181                 return (AE_BAD_HEADER);
 182         }
 183
 184         return (AE_OK);
 185 }
 186
 187 /*******************************************************************************
 188  *
 189  * FUNCTION:    acpi_tb_sum_table
 190  *
 191  * PARAMETERS:  Buffer              - Buffer to sum
 192  *              Length              - Size of the buffer
 193  *
 194  * RETURN:      8 bit sum of buffer
 195  *
 196  * DESCRIPTION: Computes an 8 bit sum of the buffer(length) and returns it.
 197  *
 198  ******************************************************************************/
 199
 200 u8 acpi_tb_sum_table(void *buffer, u32 length)
 201 {
 202         acpi_native_uint i;
 203         u8 sum = 0;
 204
 205         if (!buffer || !length) {
 206                 return (0);
 207         }
 208
 209         for (i = 0; i < length; i++) {
 210                 sum = (u8) (sum + ((u8 *) buffer)[i]);
 211         }
 212         return (sum);
 213 }
 214
 215 /*******************************************************************************
 216  *
 217  * FUNCTION:    acpi_tb_generate_checksum
 218  *
 219  * PARAMETERS:  Table               - Pointer to a valid ACPI table (with a
 220  *                                    standard ACPI header)
 221  *
 222  * RETURN:      8 bit checksum of buffer
 223  *
 224  * DESCRIPTION: Computes an 8 bit checksum of the table.
 225  *
 226  ******************************************************************************/
 227
 228 u8 acpi_tb_generate_checksum(struct acpi_table_header * table)
 229 {
 230         u8 checksum;
 231
 232         /* Sum the entire table as-is */
 233
 234         checksum = acpi_tb_sum_table(table, table->length);
 235
 236         /* Subtract off the existing checksum value in the table */
 237
 238         checksum = (u8) (checksum - table->checksum);
 239
 240         /* Compute the final checksum */
 241
 242         checksum = (u8) (0 - checksum);
 243         return (checksum);
 244 }
 245
 246 /*******************************************************************************
 247  *
 248  * FUNCTION:    acpi_tb_set_checksum
 249  *
 250  * PARAMETERS:  Table               - Pointer to a valid ACPI table (with a
 251  *                                    standard ACPI header)
 252  *
 253  * RETURN:      None. Sets the table checksum field
 254  *
 255  * DESCRIPTION: Computes an 8 bit checksum of the table and inserts the
 256  *              checksum into the table header.
 257  *
 258  ******************************************************************************/
 259
 260 void acpi_tb_set_checksum(struct acpi_table_header *table)
 261 {
 262
 263         table->checksum = acpi_tb_generate_checksum(table);
 264 }
 265
 266 /*******************************************************************************
 267  *
 268  * FUNCTION:    acpi_tb_verify_table_checksum
 269  *
 270  * PARAMETERS:  *table_header           - ACPI table to verify
 271  *
 272  * RETURN:      8 bit checksum of table
 273  *
 274  * DESCRIPTION: Generates an 8 bit checksum of table and returns and compares
 275  *              it to the existing checksum value.
 276  *
 277  ******************************************************************************/
 278
 279 acpi_status
 280 acpi_tb_verify_table_checksum(struct acpi_table_header *table_header)
 281 {
 282         u8 checksum;
 283
 284         ACPI_FUNCTION_TRACE(tb_verify_table_checksum);
 285
 286         /* Compute the checksum on the table */
 287
 288         checksum = acpi_tb_generate_checksum(table_header);
 289
 290         /* Checksum ok? */
 291
 292         if (checksum == table_header->checksum) {
 293                 return_ACPI_STATUS(AE_OK);
 294         }
 295
 296         ACPI_WARNING((AE_INFO,
 297                       "Incorrect checksum in table [%4.4s] - is %2.2X, should be %2.2X",
 298                       table_header->signature, table_header->checksum,
 299                       checksum));
 300
 301         return_ACPI_STATUS(AE_BAD_CHECKSUM);
 302 }
 303
 304 #ifdef ACPI_OBSOLETE_FUNCTIONS
 305 /*******************************************************************************
 306  *
 307  * FUNCTION:    acpi_tb_handle_to_object
 308  *
 309  * PARAMETERS:  table_id            - Id for which the function is searching
 310  *              table_desc          - Pointer to return the matching table
 311  *                                      descriptor.
 312  *
 313  * RETURN:      Search the tables to find one with a matching table_id and
 314  *              return a pointer to that table descriptor.
 315  *
 316  ******************************************************************************/
 317
 318 acpi_status
 319 acpi_tb_handle_to_object(u16 table_id,
 320                          struct acpi_table_desc **return_table_desc)
 321 {
 322         u32 i;
 323         struct acpi_table_desc *table_desc;
 324
 325         ACPI_FUNCTION_NAME(tb_handle_to_object);
 326
 327         for (i = 0; i < ACPI_TABLE_MAX; i++) {
 328                 table_desc = acpi_gbl_table_lists[i].next;
 329                 while (table_desc) {
 330                         if (table_desc->table_id == table_id) {
 331                                 *return_table_desc = table_desc;
 332                                 return (AE_OK);
 333                         }
 334
 335                         table_desc = table_desc->next;
 336                 }
 337         }
 338
 339         ACPI_ERROR((AE_INFO, "TableId=%X does not exist", table_id));
 340         return (AE_BAD_PARAMETER);
 341 }
 342 #endif