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path: root/drivers/acpi/acpica/utcksum.c
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Diffstat (limited to 'drivers/acpi/acpica/utcksum.c')
-rw-r--r--drivers/acpi/acpica/utcksum.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/utcksum.c b/drivers/acpi/acpica/utcksum.c
new file mode 100644
index 000000000000..c166e4c05ab6
--- /dev/null
+++ b/drivers/acpi/acpica/utcksum.c
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+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: utcksum - Support generating table checksums
+ *
+ * Copyright (C) 2000 - 2022, Intel Corp.
+ *
+ *****************************************************************************/
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acutils.h"
+
+/* This module used for application-level code only */
+
+#define _COMPONENT ACPI_CA_DISASSEMBLER
+ACPI_MODULE_NAME("utcksum")
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_ut_verify_checksum
+ *
+ * PARAMETERS: table - ACPI table to verify
+ * length - Length of entire table
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Verifies that the table checksums to zero. Optionally returns
+ * exception on bad checksum.
+ * Note: We don't have to check for a CDAT here, since CDAT is
+ * not in the RSDT/XSDT, and the CDAT table is never installed
+ * via ACPICA.
+ *
+ ******************************************************************************/
+acpi_status acpi_ut_verify_checksum(struct acpi_table_header *table, u32 length)
+{
+ u8 checksum;
+
+ /*
+ * FACS/S3PT:
+ * They are the odd tables, have no standard ACPI header and no checksum
+ */
+ if (ACPI_COMPARE_NAMESEG(table->signature, ACPI_SIG_S3PT) ||
+ ACPI_COMPARE_NAMESEG(table->signature, ACPI_SIG_FACS)) {
+ return (AE_OK);
+ }
+
+ /* Compute the checksum on the table */
+
+ length = table->length;
+ checksum =
+ acpi_ut_generate_checksum(ACPI_CAST_PTR(u8, table), length,
+ table->checksum);
+
+ /* Computed checksum matches table? */
+
+ if (checksum != table->checksum) {
+ ACPI_BIOS_WARNING((AE_INFO,
+ "Incorrect checksum in table [%4.4s] - 0x%2.2X, "
+ "should be 0x%2.2X",
+ table->signature, table->checksum,
+ table->checksum - checksum));
+
+#if (ACPI_CHECKSUM_ABORT)
+ return (AE_BAD_CHECKSUM);
+#endif
+ }
+
+ return (AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_ut_verify_cdat_checksum
+ *
+ * PARAMETERS: table - CDAT ACPI table to verify
+ * length - Length of entire table
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Verifies that the CDAT table checksums to zero. Optionally
+ * returns an exception on bad checksum.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ut_verify_cdat_checksum(struct acpi_table_cdat *cdat_table, u32 length)
+{
+ u8 checksum;
+
+ /* Compute the checksum on the table */
+
+ checksum = acpi_ut_generate_checksum(ACPI_CAST_PTR(u8, cdat_table),
+ cdat_table->length,
+ cdat_table->checksum);
+
+ /* Computed checksum matches table? */
+
+ if (checksum != cdat_table->checksum) {
+ ACPI_BIOS_WARNING((AE_INFO,
+ "Incorrect checksum in table [%4.4s] - 0x%2.2X, "
+ "should be 0x%2.2X",
+ acpi_gbl_CDAT, cdat_table->checksum,
+ checksum));
+
+#if (ACPI_CHECKSUM_ABORT)
+ return (AE_BAD_CHECKSUM);
+#endif
+ }
+
+ cdat_table->checksum = checksum;
+ return (AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_ut_generate_checksum
+ *
+ * PARAMETERS: table - Pointer to table to be checksummed
+ * length - Length of the table
+ * original_checksum - Value of the checksum field
+ *
+ * RETURN: 8 bit checksum of buffer
+ *
+ * DESCRIPTION: Computes an 8 bit checksum of the table.
+ *
+ ******************************************************************************/
+
+u8 acpi_ut_generate_checksum(void *table, u32 length, u8 original_checksum)
+{
+ u8 checksum;
+
+ /* Sum the entire table as-is */
+
+ checksum = acpi_ut_checksum((u8 *)table, length);
+
+ /* Subtract off the existing checksum value in the table */
+
+ checksum = (u8)(checksum - original_checksum);
+
+ /* Compute and return the final checksum */
+
+ checksum = (u8)(0 - checksum);
+ return (checksum);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_ut_checksum
+ *
+ * PARAMETERS: buffer - Pointer to memory region to be checked
+ * length - Length of this memory region
+ *
+ * RETURN: Checksum (u8)
+ *
+ * DESCRIPTION: Calculates circular checksum of memory region.
+ *
+ ******************************************************************************/
+
+u8 acpi_ut_checksum(u8 *buffer, u32 length)
+{
+ u8 sum = 0;
+ u8 *end = buffer + length;
+
+ while (buffer < end) {
+ sum = (u8)(sum + *(buffer++));
+ }
+
+ return (sum);
+}