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                 /* Compare Revision and oem_table_id */
  84
  85                 if ((table_desc->loaded_into_namespace) &&
  86                     (table_desc->pointer->revision ==
  87                      new_table_desc->pointer->revision) &&
  88                     (!ACPI_MEMCMP(table_desc->pointer->oem_table_id,
  89                                   new_table_desc->pointer->oem_table_id, 8))) {
  90                         /* This table is already installed */
  91
  92                         ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
  93                                           "Table [%4.4s] already installed: Rev %X oem_table_id [%8.8s]\n",
  94                                           new_table_desc->pointer->signature,
  95                                           new_table_desc->pointer->revision,
  96                                           new_table_desc->pointer->
  97                                           oem_table_id));
  98
  99                         new_table_desc->owner_id = table_desc->owner_id;
 100                         new_table_desc->installed_desc = table_desc;
 101
 102                         return_ACPI_STATUS(AE_ALREADY_EXISTS);
 103                 }
 104
 105                 /* Get next table on the list */
 106
 107                 table_desc = table_desc->next;
 108         }
 109
 110         return_ACPI_STATUS(AE_OK);
 111 }
 112
 113 /*******************************************************************************
 114  *
 115  * FUNCTION:    acpi_tb_validate_table_header
 116  *
 117  * PARAMETERS:  table_header        - Logical pointer to the table
 118  *
 119  * RETURN:      Status
 120  *
 121  * DESCRIPTION: Check an ACPI table header for validity
 122  *
 123  * NOTE:  Table pointers are validated as follows:
 124  *          1) Table pointer must point to valid physical memory
 125  *          2) Signature must be 4 ASCII chars, even if we don't recognize the
 126  *             name
 127  *          3) Table must be readable for length specified in the header
 128  *          4) Table checksum must be valid (with the exception of the FACS
 129  *              which has no checksum because it contains variable fields)
 130  *
 131  ******************************************************************************/
 132
 133 acpi_status
 134 acpi_tb_validate_table_header(struct acpi_table_header *table_header)
 135 {
 136         acpi_name signature;
 137
 138         ACPI_FUNCTION_NAME("tb_validate_table_header");
 139
 140         /* Verify that this is a valid address */
 141
 142         if (!acpi_os_readable(table_header, sizeof(struct acpi_table_header))) {
 143                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 144                                   "Cannot read table header at %p\n",
 145                                   table_header));
 146
 147                 return (AE_BAD_ADDRESS);
 148         }
 149
 150         /* Ensure that the signature is 4 ASCII characters */
 151
 152         ACPI_MOVE_32_TO_32(&signature, table_header->signature);
 153         if (!acpi_ut_valid_acpi_name(signature)) {
 154                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 155                                   "Table signature at %p [%p] has invalid characters\n",
 156                                   table_header, &signature));
 157
 158                 ACPI_REPORT_WARNING(("Invalid table signature found: [%4.4s]\n",
 159                                      (char *)&signature));
 160
 161                 ACPI_DUMP_BUFFER(table_header,
 162                                  sizeof(struct acpi_table_header));
 163                 return (AE_BAD_SIGNATURE);
 164         }
 165
 166         /* Validate the table length */
 167
 168         if (table_header->length < sizeof(struct acpi_table_header)) {
 169                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 170                                   "Invalid length in table header %p name %4.4s\n",
 171                                   table_header, (char *)&signature));
 172
 173                 ACPI_REPORT_WARNING(("Invalid table header length (0x%X) found\n", (u32) table_header->length));
 174
 175                 ACPI_DUMP_BUFFER(table_header,
 176                                  sizeof(struct acpi_table_header));
 177                 return (AE_BAD_HEADER);
 178         }
 179
 180         return (AE_OK);
 181 }
 182
 183 /*******************************************************************************
 184  *
 185  * FUNCTION:    acpi_tb_verify_table_checksum
 186  *
 187  * PARAMETERS:  *table_header           - ACPI table to verify
 188  *
 189  * RETURN:      8 bit checksum of table
 190  *
 191  * DESCRIPTION: Does an 8 bit checksum of table and returns status.  A correct
 192  *              table should have a checksum of 0.
 193  *
 194  ******************************************************************************/
 195
 196 acpi_status
 197 acpi_tb_verify_table_checksum(struct acpi_table_header * table_header)
 198 {
 199         u8 checksum;
 200         acpi_status status = AE_OK;
 201
 202         ACPI_FUNCTION_TRACE("tb_verify_table_checksum");
 203
 204         /* Compute the checksum on the table */
 205
 206         checksum =
 207             acpi_tb_generate_checksum(table_header, table_header->length);
 208
 209         /* Return the appropriate exception */
 210
 211         if (checksum) {
 212                 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));
 213
 214                 status = AE_BAD_CHECKSUM;
 215         }
 216         return_ACPI_STATUS(status);
 217 }
 218
 219 /*******************************************************************************
 220  *
 221  * FUNCTION:    acpi_tb_generate_checksum
 222  *
 223  * PARAMETERS:  Buffer              - Buffer to checksum
 224  *              Length              - Size of the buffer
 225  *
 226  * RETURN:      8 bit checksum of buffer
 227  *
 228  * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
 229  *
 230  ******************************************************************************/
 231
 232 u8 acpi_tb_generate_checksum(void *buffer, u32 length)
 233 {
 234         const u8 *limit;
 235         const u8 *rover;
 236         u8 sum = 0;
 237
 238         if (buffer && length) {
 239                 /*  Buffer and Length are valid   */
 240
 241                 limit = (u8 *) buffer + length;
 242
 243                 for (rover = buffer; rover < limit; rover++) {
 244                         sum = (u8) (sum + *rover);
 245                 }
 246         }
 247         return (sum);
 248 }
 249
 250 #ifdef ACPI_OBSOLETE_FUNCTIONS
 251 /*******************************************************************************
 252  *
 253  * FUNCTION:    acpi_tb_handle_to_object
 254  *
 255  * PARAMETERS:  table_id            - Id for which the function is searching
 256  *              table_desc          - Pointer to return the matching table
 257  *                                      descriptor.
 258  *
 259  * RETURN:      Search the tables to find one with a matching table_id and
 260  *              return a pointer to that table descriptor.
 261  *
 262  ******************************************************************************/
 263
 264 acpi_status
 265 acpi_tb_handle_to_object(u16 table_id,
 266                          struct acpi_table_desc ** return_table_desc)
 267 {
 268         u32 i;
 269         struct acpi_table_desc *table_desc;
 270
 271         ACPI_FUNCTION_NAME("tb_handle_to_object");
 272
 273         for (i = 0; i < ACPI_TABLE_MAX; i++) {
 274                 table_desc = acpi_gbl_table_lists[i].next;
 275                 while (table_desc) {
 276                         if (table_desc->table_id == table_id) {
 277                                 *return_table_desc = table_desc;
 278                                 return (AE_OK);
 279                         }
 280
 281                         table_desc = table_desc->next;
 282                 }
 283         }
 284
 285         ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "table_id=%X does not exist\n",
 286                           table_id));
 287         return (AE_BAD_PARAMETER);
 288 }
 289 #endif