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
  45 #include <acpi/acpi.h>
  46 #include <acpi/actables.h>
  47
  48
  49 #define _COMPONENT          ACPI_TABLES
  50          ACPI_MODULE_NAME    ("tbutils")
  51
  52
  53 /*******************************************************************************
  54  *
  55  * FUNCTION:    acpi_tb_handle_to_object
  56  *
  57  * PARAMETERS:  table_id            - Id for which the function is searching
  58  *              table_desc          - Pointer to return the matching table
  59  *                                      descriptor.
  60  *
  61  * RETURN:      Search the tables to find one with a matching table_id and
  62  *              return a pointer to that table descriptor.
  63  *
  64  ******************************************************************************/
  65 #ifdef ACPI_FUTURE_USAGE
  66 acpi_status
  67 acpi_tb_handle_to_object (
  68         u16                             table_id,
  69         struct acpi_table_desc          **return_table_desc)
  70 {
  71         u32                             i;
  72         struct acpi_table_desc          *table_desc;
  73
  74
  75         ACPI_FUNCTION_NAME ("tb_handle_to_object");
  76
  77
  78         for (i = 0; i < ACPI_TABLE_MAX; i++) {
  79                 table_desc = acpi_gbl_table_lists[i].next;
  80                 while (table_desc) {
  81                         if (table_desc->table_id == table_id) {
  82                                 *return_table_desc = table_desc;
  83                                 return (AE_OK);
  84                         }
  85
  86                         table_desc = table_desc->next;
  87                 }
  88         }
  89
  90         ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "table_id=%X does not exist\n", table_id));
  91         return (AE_BAD_PARAMETER);
  92 }
  93 #endif  /*  ACPI_FUTURE_USAGE  */
  94
  95
  96 /*******************************************************************************
  97  *
  98  * FUNCTION:    acpi_tb_validate_table_header
  99  *
 100  * PARAMETERS:  table_header        - Logical pointer to the table
 101  *
 102  * RETURN:      Status
 103  *
 104  * DESCRIPTION: Check an ACPI table header for validity
 105  *
 106  * NOTE:  Table pointers are validated as follows:
 107  *          1) Table pointer must point to valid physical memory
 108  *          2) Signature must be 4 ASCII chars, even if we don't recognize the
 109  *             name
 110  *          3) Table must be readable for length specified in the header
 111  *          4) Table checksum must be valid (with the exception of the FACS
 112  *              which has no checksum because it contains variable fields)
 113  *
 114  ******************************************************************************/
 115
 116 acpi_status
 117 acpi_tb_validate_table_header (
 118         struct acpi_table_header        *table_header)
 119 {
 120         acpi_name                       signature;
 121
 122
 123         ACPI_FUNCTION_NAME ("tb_validate_table_header");
 124
 125
 126         /* Verify that this is a valid address */
 127
 128         if (!acpi_os_readable (table_header, sizeof (struct acpi_table_header))) {
 129                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 130                         "Cannot read table header at %p\n", table_header));
 131                 return (AE_BAD_ADDRESS);
 132         }
 133
 134         /* Ensure that the signature is 4 ASCII characters */
 135
 136         ACPI_MOVE_32_TO_32 (&signature, table_header->signature);
 137         if (!acpi_ut_valid_acpi_name (signature)) {
 138                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 139                         "Table signature at %p [%p] has invalid characters\n",
 140                         table_header, &signature));
 141
 142                 ACPI_REPORT_WARNING (("Invalid table signature found: [%4.4s]\n",
 143                         (char *) &signature));
 144                 ACPI_DUMP_BUFFER (table_header, sizeof (struct acpi_table_header));
 145                 return (AE_BAD_SIGNATURE);
 146         }
 147
 148         /* Validate the table length */
 149
 150         if (table_header->length < sizeof (struct acpi_table_header)) {
 151                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 152                         "Invalid length in table header %p name %4.4s\n",
 153                         table_header, (char *) &signature));
 154
 155                 ACPI_REPORT_WARNING (("Invalid table header length (0x%X) found\n",
 156                         (u32) table_header->length));
 157                 ACPI_DUMP_BUFFER (table_header, sizeof (struct acpi_table_header));
 158                 return (AE_BAD_HEADER);
 159         }
 160
 161         return (AE_OK);
 162 }
 163
 164
 165 /*******************************************************************************
 166  *
 167  * FUNCTION:    acpi_tb_verify_table_checksum
 168  *
 169  * PARAMETERS:  *table_header           - ACPI table to verify
 170  *
 171  * RETURN:      8 bit checksum of table
 172  *
 173  * DESCRIPTION: Does an 8 bit checksum of table and returns status.  A correct
 174  *              table should have a checksum of 0.
 175  *
 176  ******************************************************************************/
 177
 178 acpi_status
 179 acpi_tb_verify_table_checksum (
 180         struct acpi_table_header        *table_header)
 181 {
 182         u8                              checksum;
 183         acpi_status                     status = AE_OK;
 184
 185
 186         ACPI_FUNCTION_TRACE ("tb_verify_table_checksum");
 187
 188
 189         /* Compute the checksum on the table */
 190
 191         checksum = acpi_tb_checksum (table_header, table_header->length);
 192
 193         /* Return the appropriate exception */
 194
 195         if (checksum) {
 196                 ACPI_REPORT_WARNING (("Invalid checksum in table [%4.4s] (%02X, sum %02X is not zero)\n",
 197                         table_header->signature, (u32) table_header->checksum, (u32) checksum));
 198
 199                 status = AE_BAD_CHECKSUM;
 200         }
 201         return_ACPI_STATUS (status);
 202 }
 203
 204
 205 /*******************************************************************************
 206  *
 207  * FUNCTION:    acpi_tb_checksum
 208  *
 209  * PARAMETERS:  Buffer              - Buffer to checksum
 210  *              Length              - Size of the buffer
 211  *
 212  * RETURNS      8 bit checksum of buffer
 213  *
 214  * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
 215  *
 216  ******************************************************************************/
 217
 218 u8
 219 acpi_tb_checksum (
 220         void                            *buffer,
 221         u32                             length)
 222 {
 223         const u8                        *limit;
 224         const u8                        *rover;
 225         u8                              sum = 0;
 226
 227
 228         if (buffer && length) {
 229                 /*  Buffer and Length are valid   */
 230
 231                 limit = (u8 *) buffer + length;
 232
 233                 for (rover = buffer; rover < limit; rover++) {
 234                         sum = (u8) (sum + *rover);
 235                 }
 236         }
 237         return (sum);
 238 }
 239
 240