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 - 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                         /* Match: this table is already installed */
 100
 101                         ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
 102                                           "Table [%4.4s] already installed: Rev %X oem_table_id [%8.8s]\n",
 103                                           new_table_desc->pointer->signature,
 104                                           new_table_desc->pointer->revision,
 105                                           new_table_desc->pointer->
 106                                           oem_table_id));
 107
 108                         new_table_desc->owner_id = table_desc->owner_id;
 109                         new_table_desc->installed_desc = table_desc;
 110
 111                         return_ACPI_STATUS(AE_ALREADY_EXISTS);
 112                 }
 113
 114                 /* Get next table on the list */
 115
 116                 table_desc = table_desc->next;
 117         }
 118
 119         return_ACPI_STATUS(AE_OK);
 120 }
 121
 122 /*******************************************************************************
 123  *
 124  * FUNCTION:    acpi_tb_validate_table_header
 125  *
 126  * PARAMETERS:  table_header        - Logical pointer to the table
 127  *
 128  * RETURN:      Status
 129  *
 130  * DESCRIPTION: Check an ACPI table header for validity
 131  *
 132  * NOTE:  Table pointers are validated as follows:
 133  *          1) Table pointer must point to valid physical memory
 134  *          2) Signature must be 4 ASCII chars, even if we don't recognize the
 135  *             name
 136  *          3) Table must be readable for length specified in the header
 137  *          4) Table checksum must be valid (with the exception of the FACS
 138  *              which has no checksum because it contains variable fields)
 139  *
 140  ******************************************************************************/
 141
 142 acpi_status
 143 acpi_tb_validate_table_header(struct acpi_table_header *table_header)
 144 {
 145         acpi_name signature;
 146
 147         ACPI_FUNCTION_ENTRY();
 148
 149         /* Verify that this is a valid address */
 150
 151         if (!acpi_os_readable(table_header, sizeof(struct acpi_table_header))) {
 152                 ACPI_ERROR((AE_INFO,
 153                             "Cannot read table header at %p", table_header));
 154
 155                 return (AE_BAD_ADDRESS);
 156         }
 157
 158         /* Ensure that the signature is 4 ASCII characters */
 159
 160         ACPI_MOVE_32_TO_32(&signature, table_header->signature);
 161         if (!acpi_ut_valid_acpi_name(signature)) {
 162                 ACPI_ERROR((AE_INFO,
 163                             "Table signature at %p [%p] has invalid characters",
 164                             table_header, &signature));
 165
 166                 ACPI_WARNING((AE_INFO, "Invalid table signature found: [%4.4s]",
 167                               ACPI_CAST_PTR(char, &signature)));
 168
 169                 ACPI_DUMP_BUFFER(table_header,
 170                                  sizeof(struct acpi_table_header));
 171                 return (AE_BAD_SIGNATURE);
 172         }
 173
 174         /* Validate the table length */
 175
 176         if (table_header->length < sizeof(struct acpi_table_header)) {
 177                 ACPI_ERROR((AE_INFO,
 178                             "Invalid length in table header %p name %4.4s",
 179                             table_header, (char *)&signature));
 180
 181                 ACPI_WARNING((AE_INFO,
 182                               "Invalid table header length (0x%X) found",
 183                               (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_WARNING((AE_INFO,
 223                               "Invalid checksum in table [%4.4s] (%02X, sum %02X is not zero)",
 224                               table_header->signature,
 225                               (u32) table_header->checksum, (u32) checksum));
 226
 227                 status = AE_BAD_CHECKSUM;
 228         }
 229         return_ACPI_STATUS(status);
 230 }
 231
 232 /*******************************************************************************
 233  *
 234  * FUNCTION:    acpi_tb_generate_checksum
 235  *
 236  * PARAMETERS:  Buffer              - Buffer to checksum
 237  *              Length              - Size of the buffer
 238  *
 239  * RETURN:      8 bit checksum of buffer
 240  *
 241  * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
 242  *
 243  ******************************************************************************/
 244
 245 u8 acpi_tb_generate_checksum(void *buffer, u32 length)
 246 {
 247         u8 *end_buffer;
 248         u8 *rover;
 249         u8 sum = 0;
 250
 251         if (buffer && length) {
 252                 /*  Buffer and Length are valid   */
 253
 254                 end_buffer = ACPI_ADD_PTR(u8, buffer, length);
 255
 256                 for (rover = buffer; rover < end_buffer; rover++) {
 257                         sum = (u8) (sum + *rover);
 258                 }
 259         }
 260         return (sum);
 261 }
 262
 263 #ifdef ACPI_OBSOLETE_FUNCTIONS
 264 /*******************************************************************************
 265  *
 266  * FUNCTION:    acpi_tb_handle_to_object
 267  *
 268  * PARAMETERS:  table_id            - Id for which the function is searching
 269  *              table_desc          - Pointer to return the matching table
 270  *                                      descriptor.
 271  *
 272  * RETURN:      Search the tables to find one with a matching table_id and
 273  *              return a pointer to that table descriptor.
 274  *
 275  ******************************************************************************/
 276
 277 acpi_status
 278 acpi_tb_handle_to_object(u16 table_id,
 279                          struct acpi_table_desc ** return_table_desc)
 280 {
 281         u32 i;
 282         struct acpi_table_desc *table_desc;
 283
 284         ACPI_FUNCTION_NAME("tb_handle_to_object");
 285
 286         for (i = 0; i < ACPI_TABLE_MAX; i++) {
 287                 table_desc = acpi_gbl_table_lists[i].next;
 288                 while (table_desc) {
 289                         if (table_desc->table_id == table_id) {
 290                                 *return_table_desc = table_desc;
 291                                 return (AE_OK);
 292                         }
 293
 294                         table_desc = table_desc->next;
 295                 }
 296         }
 297
 298         ACPI_ERROR((AE_INFO, "table_id=%X does not exist", table_id));
 299         return (AE_BAD_PARAMETER);
 300 }
 301 #endif