ACPICA: Emit warning if two FACS or DSDT tables found in the FADT

Checks if there are two valid but different addresses for the
FACS and DSDT within the FADT (mismatch between the 32-bit and
64-bit fields.)
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/tables/tbfadt.c

@@ -286,14 +286,27 @@ static void acpi_tb_convert_fadt(void)
 
 	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
 
-	/* Expand the 32-bit FACS and DSDT addresses to 64-bit as necessary */
-
+	/*
+	 * Expand the 32-bit FACS and DSDT addresses to 64-bit as necessary.
+	 * Later code will always use the X 64-bit field. Also, check for an
+	 * address mismatch between the 32-bit and 64-bit address fields
+	 * (FIRMWARE_CTRL/X_FIRMWARE_CTRL, DSDT/X_DSDT) which would indicate
+	 * the presence of two FACS or two DSDT tables.
+	 */
 	if (!acpi_gbl_FADT.Xfacs) {
 		acpi_gbl_FADT.Xfacs = (u64) acpi_gbl_FADT.facs;
+	} else if (acpi_gbl_FADT.facs &&
+		   (acpi_gbl_FADT.Xfacs != (u64) acpi_gbl_FADT.facs)) {
+		ACPI_WARNING((AE_INFO,
+		    "32/64 FACS address mismatch in FADT - two FACS tables!"));
 	}
 
 	if (!acpi_gbl_FADT.Xdsdt) {
 		acpi_gbl_FADT.Xdsdt = (u64) acpi_gbl_FADT.dsdt;
+	} else if (acpi_gbl_FADT.dsdt &&
+		   (acpi_gbl_FADT.Xdsdt != (u64) acpi_gbl_FADT.dsdt)) {
+		ACPI_WARNING((AE_INFO,
+		    "32/64 DSDT address mismatch in FADT - two DSDT tables!"));
 	}
 
 	/*