aboutsummaryrefslogtreecommitdiff
path: root/drivers/acpi/tables/tbutils.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/acpi/tables/tbutils.c')
-rw-r--r--drivers/acpi/tables/tbutils.c122
1 files changed, 84 insertions, 38 deletions
diff --git a/drivers/acpi/tables/tbutils.c b/drivers/acpi/tables/tbutils.c
index b463d4b8882..f8d28ae8811 100644
--- a/drivers/acpi/tables/tbutils.c
+++ b/drivers/acpi/tables/tbutils.c
@@ -193,73 +193,119 @@ acpi_tb_validate_table_header(struct acpi_table_header *table_header)
/*******************************************************************************
*
- * FUNCTION: acpi_tb_verify_table_checksum
+ * FUNCTION: acpi_tb_sum_table
*
- * PARAMETERS: *table_header - ACPI table to verify
+ * PARAMETERS: Buffer - Buffer to sum
+ * Length - Size of the buffer
*
- * RETURN: 8 bit checksum of table
+ * RETURN: 8 bit sum of buffer
*
- * DESCRIPTION: Does an 8 bit checksum of table and returns status. A correct
- * table should have a checksum of 0.
+ * DESCRIPTION: Computes an 8 bit sum of the buffer(length) and returns it.
*
******************************************************************************/
-acpi_status
-acpi_tb_verify_table_checksum(struct acpi_table_header * table_header)
+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;
- acpi_status status = AE_OK;
- ACPI_FUNCTION_TRACE("tb_verify_table_checksum");
+ /* Sum the entire table as-is */
- /* Compute the checksum on the table */
+ checksum = acpi_tb_sum_table(table, table->length);
- checksum =
- acpi_tb_generate_checksum(table_header, table_header->length);
+ /* Subtract off the existing checksum value in the table */
- /* Return the appropriate exception */
+ checksum = (u8) (checksum - table->checksum);
- if (checksum) {
- ACPI_WARNING((AE_INFO,
- "Invalid checksum in table [%4.4s] (%02X, sum %02X is not zero)",
- table_header->signature,
- (u32) table_header->checksum, (u32) checksum));
+ /* Compute the final checksum */
- status = AE_BAD_CHECKSUM;
- }
- return_ACPI_STATUS(status);
+ checksum = (u8) (0 - checksum);
+ return (checksum);
}
/*******************************************************************************
*
- * FUNCTION: acpi_tb_generate_checksum
+ * FUNCTION: acpi_tb_set_checksum
*
- * PARAMETERS: Buffer - Buffer to checksum
- * Length - Size of the buffer
+ * PARAMETERS: Table - Pointer to a valid ACPI table (with a
+ * standard ACPI header)
*
- * RETURN: 8 bit checksum of buffer
+ * RETURN: None. Sets the table checksum field
*
- * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
+ * DESCRIPTION: Computes an 8 bit checksum of the table and inserts the
+ * checksum into the table header.
*
******************************************************************************/
-u8 acpi_tb_generate_checksum(void *buffer, u32 length)
+void acpi_tb_set_checksum(struct acpi_table_header *table)
{
- u8 *end_buffer;
- u8 *rover;
- u8 sum = 0;
- if (buffer && length) {
+ 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 */
- /* Buffer and Length are valid */
+ checksum = acpi_tb_generate_checksum(table_header);
- end_buffer = ACPI_ADD_PTR(u8, buffer, length);
+ /* Checksum ok? */
- for (rover = buffer; rover < end_buffer; rover++) {
- sum = (u8) (sum + *rover);
- }
+ if (checksum == table_header->checksum) {
+ return_ACPI_STATUS(AE_OK);
}
- return (sum);
+
+ 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
@@ -278,7 +324,7 @@ u8 acpi_tb_generate_checksum(void *buffer, u32 length)
acpi_status
acpi_tb_handle_to_object(u16 table_id,
- struct acpi_table_desc ** return_table_desc)
+ struct acpi_table_desc **return_table_desc)
{
u32 i;
struct acpi_table_desc *table_desc;