diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 14daf48..f802dbc 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2690,6 +2690,24 @@
 	if ((tf->protocol = ata_scsi_map_proto(cdb[1])) == ATA_PROT_UNKNOWN)
 		goto invalid_fld;
 
+	/*
+	 * Filter TPM commands by default. These provide an
+	 * essentially uncontrolled encrypted "back door" between
+	 * applications and the disk. Set libata.allow_tpm=1 if you
+	 * have a real reason for wanting to use them. This ensures
+	 * that installed software cannot easily mess stuff up without
+	 * user intent. DVR type users will probably ship with this enabled
+	 * for movie content management.
+	 *
+	 * Note that for ATA8 we can issue a DCS change and DCS freeze lock
+	 * for this and should do in future but that it is not sufficient as
+	 * DCS is an optional feature set. Thus we also do the software filter
+	 * so that we comply with the TC consortium stated goal that the user
+	 * can turn off TC features of their system.
+	 */
+	if (tf->command >= 0x5C && tf->command <= 0x5F && !libata_allow_tpm)
+		goto invalid_fld;
+
 	/* We may not issue DMA commands if no DMA mode is set */
 	if (tf->protocol == ATA_PROT_DMA && dev->dma_mode == 0)
 		goto invalid_fld;