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linux/drivers/acpi/tables/tbutils.c

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/******************************************************************************
*
* Module Name: tbutils - Table manipulation utilities
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2006, R. Byron Moore
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*/
#include <acpi/acpi.h>
#include <acpi/actables.h>
#define _COMPONENT ACPI_TABLES
ACPI_MODULE_NAME("tbutils")
/* Local prototypes */
#ifdef ACPI_OBSOLETE_FUNCTIONS
acpi_status
acpi_tb_handle_to_object(u16 table_id, struct acpi_table_desc **table_desc);
#endif
/*******************************************************************************
*
* FUNCTION: acpi_tb_is_table_installed
*
* PARAMETERS: new_table_desc - Descriptor for new table being installed
*
* RETURN: Status - AE_ALREADY_EXISTS if the table is already installed
*
* DESCRIPTION: Determine if an ACPI table is already installed
*
* MUTEX: Table data structures should be locked
*
******************************************************************************/
acpi_status acpi_tb_is_table_installed(struct acpi_table_desc *new_table_desc)
{
struct acpi_table_desc *table_desc;
ACPI_FUNCTION_TRACE(tb_is_table_installed);
/* Get the list descriptor and first table descriptor */
table_desc = acpi_gbl_table_lists[new_table_desc->type].next;
/* Examine all installed tables of this type */
while (table_desc) {
/*
* If the table lengths match, perform a full bytewise compare. This
* means that we will allow tables with duplicate oem_table_id(s), as
* long as the tables are different in some way.
*
* Checking if the table has been loaded into the namespace means that
* we don't check for duplicate tables during the initial installation
* of tables within the RSDT/XSDT.
*/
if ((table_desc->loaded_into_namespace) &&
(table_desc->pointer->length ==
new_table_desc->pointer->length)
&&
(!ACPI_MEMCMP
(table_desc->pointer, new_table_desc->pointer,
new_table_desc->pointer->length))) {
/* Match: this table is already installed */
ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
"Table [%4.4s] already installed: Rev %X OemTableId [%8.8s]\n",
new_table_desc->pointer->signature,
new_table_desc->pointer->revision,
new_table_desc->pointer->
oem_table_id));
new_table_desc->owner_id = table_desc->owner_id;
new_table_desc->installed_desc = table_desc;
return_ACPI_STATUS(AE_ALREADY_EXISTS);
}
/* Get next table on the list */
table_desc = table_desc->next;
}
return_ACPI_STATUS(AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_tb_validate_table_header
*
* PARAMETERS: table_header - Logical pointer to the table
*
* RETURN: Status
*
* DESCRIPTION: Check an ACPI table header for validity
*
* NOTE: Table pointers are validated as follows:
* 1) Table pointer must point to valid physical memory
* 2) Signature must be 4 ASCII chars, even if we don't recognize the
* name
* 3) Table must be readable for length specified in the header
* 4) Table checksum must be valid (with the exception of the FACS
* which has no checksum because it contains variable fields)
*
******************************************************************************/
acpi_status
acpi_tb_validate_table_header(struct acpi_table_header *table_header)
{
acpi_name signature;
ACPI_FUNCTION_ENTRY();
/* Verify that this is a valid address */
if (!acpi_os_readable(table_header, sizeof(struct acpi_table_header))) {
ACPI_ERROR((AE_INFO,
"Cannot read table header at %p", table_header));
return (AE_BAD_ADDRESS);
}
/* Ensure that the signature is 4 ASCII characters */
ACPI_MOVE_32_TO_32(&signature, table_header->signature);
if (!acpi_ut_valid_acpi_name(signature)) {
ACPI_ERROR((AE_INFO, "Invalid table signature 0x%8.8X",
signature));
ACPI_DUMP_BUFFER(table_header,
sizeof(struct acpi_table_header));
return (AE_BAD_SIGNATURE);
}
/* Validate the table length */
if (table_header->length < sizeof(struct acpi_table_header)) {
ACPI_ERROR((AE_INFO,
"Invalid length 0x%X in table with signature %4.4s",
(u32) table_header->length,
ACPI_CAST_PTR(char, &signature)));
ACPI_DUMP_BUFFER(table_header,
sizeof(struct acpi_table_header));
return (AE_BAD_HEADER);
}
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_tb_sum_table
*
* PARAMETERS: Buffer - Buffer to sum
* Length - Size of the buffer
*
* RETURN: 8 bit sum of buffer
*
* DESCRIPTION: Computes an 8 bit sum of the buffer(length) and returns it.
*
******************************************************************************/
u8 acpi_tb_sum_table(void *buffer, u32 length)
{
acpi_native_uint i;
u8 sum = 0;
if (!buffer || !length) {
return (0);
}
for (i = 0; i < length; i++) {
sum = (u8) (sum + ((u8 *) buffer)[i]);
}
return (sum);
}
/*******************************************************************************
*
* FUNCTION: acpi_tb_generate_checksum
*
* PARAMETERS: Table - Pointer to a valid ACPI table (with a
* standard ACPI header)
*
* RETURN: 8 bit checksum of buffer
*
* DESCRIPTION: Computes an 8 bit checksum of the table.
*
******************************************************************************/
u8 acpi_tb_generate_checksum(struct acpi_table_header * table)
{
u8 checksum;
/* Sum the entire table as-is */
checksum = acpi_tb_sum_table(table, table->length);
/* Subtract off the existing checksum value in the table */
checksum = (u8) (checksum - table->checksum);
/* Compute the final checksum */
checksum = (u8) (0 - checksum);
return (checksum);
}
/*******************************************************************************
*
* FUNCTION: acpi_tb_set_checksum
*
* PARAMETERS: Table - Pointer to a valid ACPI table (with a
* standard ACPI header)
*
* RETURN: None. Sets the table checksum field
*
* DESCRIPTION: Computes an 8 bit checksum of the table and inserts the
* checksum into the table header.
*
******************************************************************************/
void acpi_tb_set_checksum(struct acpi_table_header *table)
{
table->checksum = acpi_tb_generate_checksum(table);
}
/*******************************************************************************
*
* FUNCTION: acpi_tb_verify_table_checksum
*
* PARAMETERS: *table_header - ACPI table to verify
*
* RETURN: 8 bit checksum of table
*
* DESCRIPTION: Generates an 8 bit checksum of table and returns and compares
* it to the existing checksum value.
*
******************************************************************************/
acpi_status
acpi_tb_verify_table_checksum(struct acpi_table_header *table_header)
{
u8 checksum;
ACPI_FUNCTION_TRACE(tb_verify_table_checksum);
/* Compute the checksum on the table */
checksum = acpi_tb_generate_checksum(table_header);
/* Checksum ok? */
if (checksum == table_header->checksum) {
return_ACPI_STATUS(AE_OK);
}
ACPI_WARNING((AE_INFO,
"Incorrect checksum in table [%4.4s] - is %2.2X, should be %2.2X",
table_header->signature, table_header->checksum,
checksum));
return_ACPI_STATUS(AE_BAD_CHECKSUM);
}
#ifdef ACPI_OBSOLETE_FUNCTIONS
/*******************************************************************************
*
* FUNCTION: acpi_tb_handle_to_object
*
* PARAMETERS: table_id - Id for which the function is searching
* table_desc - Pointer to return the matching table
* descriptor.
*
* RETURN: Search the tables to find one with a matching table_id and
* return a pointer to that table descriptor.
*
******************************************************************************/
acpi_status
acpi_tb_handle_to_object(u16 table_id,
struct acpi_table_desc **return_table_desc)
{
u32 i;
struct acpi_table_desc *table_desc;
ACPI_FUNCTION_NAME(tb_handle_to_object);
for (i = 0; i < ACPI_TABLE_MAX; i++) {
table_desc = acpi_gbl_table_lists[i].next;
while (table_desc) {
if (table_desc->table_id == table_id) {
*return_table_desc = table_desc;
return (AE_OK);
}
table_desc = table_desc->next;
}
}
ACPI_ERROR((AE_INFO, "TableId=%X does not exist", table_id));
return (AE_BAD_PARAMETER);
}
#endif
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