linux/drivers/acpi/tables/tbutils.c
Bob Moore a18ecf413c [ACPI] ACPICA 20050815
Implemented a full bytewise compare to determine if a table load
request is attempting to load a duplicate table. The compare is
performed if the table signatures and table lengths match. This
will allow different tables with the same OEM Table ID and
revision to be loaded.

Although the BIOS is technically violating the ACPI spec when
this happens -- it does happen -- so Linux must handle it.

Signed-off-by: Robert Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2005-08-29 23:44:25 -04:00

299 lines
9.4 KiB
C

/******************************************************************************
*
* Module Name: tbutils - Table manipulation utilities
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2005, 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
((const char *)table_desc->pointer,
(const char *)new_table_desc->pointer,
(acpi_size) new_table_desc->pointer->length))) {
/* Match: this table is already installed */
ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
"Table [%4.4s] already installed: Rev %X oem_table_id [%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_NAME("tb_validate_table_header");
/* Verify that this is a valid address */
if (!acpi_os_readable(table_header, sizeof(struct acpi_table_header))) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
"Cannot read table header at %p\n",
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_DEBUG_PRINT((ACPI_DB_ERROR,
"Table signature at %p [%p] has invalid characters\n",
table_header, &signature));
ACPI_REPORT_WARNING(("Invalid table signature found: [%4.4s]\n",
(char *)&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_DEBUG_PRINT((ACPI_DB_ERROR,
"Invalid length in table header %p name %4.4s\n",
table_header, (char *)&signature));
ACPI_REPORT_WARNING(("Invalid table header length (0x%X) found\n", (u32) table_header->length));
ACPI_DUMP_BUFFER(table_header,
sizeof(struct acpi_table_header));
return (AE_BAD_HEADER);
}
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_tb_verify_table_checksum
*
* PARAMETERS: *table_header - ACPI table to verify
*
* RETURN: 8 bit checksum of table
*
* DESCRIPTION: Does an 8 bit checksum of table and returns status. A correct
* table should have a checksum of 0.
*
******************************************************************************/
acpi_status
acpi_tb_verify_table_checksum(struct acpi_table_header * table_header)
{
u8 checksum;
acpi_status status = AE_OK;
ACPI_FUNCTION_TRACE("tb_verify_table_checksum");
/* Compute the checksum on the table */
checksum =
acpi_tb_generate_checksum(table_header, table_header->length);
/* Return the appropriate exception */
if (checksum) {
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));
status = AE_BAD_CHECKSUM;
}
return_ACPI_STATUS(status);
}
/*******************************************************************************
*
* FUNCTION: acpi_tb_generate_checksum
*
* PARAMETERS: Buffer - Buffer to checksum
* Length - Size of the buffer
*
* RETURN: 8 bit checksum of buffer
*
* DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
*
******************************************************************************/
u8 acpi_tb_generate_checksum(void *buffer, u32 length)
{
const u8 *limit;
const u8 *rover;
u8 sum = 0;
if (buffer && length) {
/* Buffer and Length are valid */
limit = (u8 *) buffer + length;
for (rover = buffer; rover < limit; rover++) {
sum = (u8) (sum + *rover);
}
}
return (sum);
}
#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_DEBUG_PRINT((ACPI_DB_ERROR, "table_id=%X does not exist\n",
table_id));
return (AE_BAD_PARAMETER);
}
#endif