git.oblomov.eu Git - linux-2.6/blob - drivers/acpi/tables/tbutils.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbutils - Table manipulation utilities
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2005, 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                      ((const char *)table_desc->pointer,
  98                       (const char *)new_table_desc->pointer,
  99                       (acpi_size) new_table_desc->pointer->length))) {
 100                         /* Match: this table is already installed */
 101
 102                         ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
 103                                           "Table [%4.4s] already installed: Rev %X oem_table_id [%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_NAME("tb_validate_table_header");
 149
 150         /* Verify that this is a valid address */
 151
 152         if (!acpi_os_readable(table_header, sizeof(struct acpi_table_header))) {
 153                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 154                                   "Cannot read table header at %p\n",
 155                                   table_header));
 156
 157                 return (AE_BAD_ADDRESS);
 158         }
 159
 160         /* Ensure that the signature is 4 ASCII characters */
 161
 162         ACPI_MOVE_32_TO_32(&signature, table_header->signature);
 163         if (!acpi_ut_valid_acpi_name(signature)) {
 164                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 165                                   "Table signature at %p [%p] has invalid characters\n",
 166                                   table_header, &signature));
 167
 168                 ACPI_REPORT_WARNING(("Invalid table signature found: [%4.4s]\n",
 169                                      (char *)&signature));
 170
 171                 ACPI_DUMP_BUFFER(table_header,
 172                                  sizeof(struct acpi_table_header));
 173                 return (AE_BAD_SIGNATURE);
 174         }
 175
 176         /* Validate the table length */
 177
 178         if (table_header->length < sizeof(struct acpi_table_header)) {
 179                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 180                                   "Invalid length in table header %p name %4.4s\n",
 181                                   table_header, (char *)&signature));
 182
 183                 ACPI_REPORT_WARNING(("Invalid table header length (0x%X) found\n", (u32) table_header->length));
 184
 185                 ACPI_DUMP_BUFFER(table_header,
 186                                  sizeof(struct acpi_table_header));
 187                 return (AE_BAD_HEADER);
 188         }
 189
 190         return (AE_OK);
 191 }
 192
 193 /*******************************************************************************
 194  *
 195  * FUNCTION:    acpi_tb_verify_table_checksum
 196  *
 197  * PARAMETERS:  *table_header           - ACPI table to verify
 198  *
 199  * RETURN:      8 bit checksum of table
 200  *
 201  * DESCRIPTION: Does an 8 bit checksum of table and returns status.  A correct
 202  *              table should have a checksum of 0.
 203  *
 204  ******************************************************************************/
 205
 206 acpi_status
 207 acpi_tb_verify_table_checksum(struct acpi_table_header * table_header)
 208 {
 209         u8 checksum;
 210         acpi_status status = AE_OK;
 211
 212         ACPI_FUNCTION_TRACE("tb_verify_table_checksum");
 213
 214         /* Compute the checksum on the table */
 215
 216         checksum =
 217             acpi_tb_generate_checksum(table_header, table_header->length);
 218
 219         /* Return the appropriate exception */
 220
 221         if (checksum) {
 222                 ACPI_REPORT_WARNING(("Invalid checksum in table [%4.4s] (%02X, sum %02X is not zero)\n", table_header->signature, (u32) table_header->checksum, (u32) checksum));
 223
 224                 status = AE_BAD_CHECKSUM;
 225         }
 226         return_ACPI_STATUS(status);
 227 }
 228
 229 /*******************************************************************************
 230  *
 231  * FUNCTION:    acpi_tb_generate_checksum
 232  *
 233  * PARAMETERS:  Buffer              - Buffer to checksum
 234  *              Length              - Size of the buffer
 235  *
 236  * RETURN:      8 bit checksum of buffer
 237  *
 238  * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
 239  *
 240  ******************************************************************************/
 241
 242 u8 acpi_tb_generate_checksum(void *buffer, u32 length)
 243 {
 244         const u8 *limit;
 245         const u8 *rover;
 246         u8 sum = 0;
 247
 248         if (buffer && length) {
 249                 /*  Buffer and Length are valid   */
 250
 251                 limit = (u8 *) buffer + length;
 252
 253                 for (rover = buffer; rover < limit; rover++) {
 254                         sum = (u8) (sum + *rover);
 255                 }
 256         }
 257         return (sum);
 258 }
 259
 260 #ifdef ACPI_OBSOLETE_FUNCTIONS
 261 /*******************************************************************************
 262  *
 263  * FUNCTION:    acpi_tb_handle_to_object
 264  *
 265  * PARAMETERS:  table_id            - Id for which the function is searching
 266  *              table_desc          - Pointer to return the matching table
 267  *                                      descriptor.
 268  *
 269  * RETURN:      Search the tables to find one with a matching table_id and
 270  *              return a pointer to that table descriptor.
 271  *
 272  ******************************************************************************/
 273
 274 acpi_status
 275 acpi_tb_handle_to_object(u16 table_id,
 276                          struct acpi_table_desc ** return_table_desc)
 277 {
 278         u32 i;
 279         struct acpi_table_desc *table_desc;
 280
 281         ACPI_FUNCTION_NAME("tb_handle_to_object");
 282
 283         for (i = 0; i < ACPI_TABLE_MAX; i++) {
 284                 table_desc = acpi_gbl_table_lists[i].next;
 285                 while (table_desc) {
 286                         if (table_desc->table_id == table_id) {
 287                                 *return_table_desc = table_desc;
 288                                 return (AE_OK);
 289                         }
 290
 291                         table_desc = table_desc->next;
 292                 }
 293         }
 294
 295         ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "table_id=%X does not exist\n",
 296                           table_id));
 297         return (AE_BAD_PARAMETER);
 298 }
 299 #endif