From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932660AbdAIWJJ (ORCPT ); Mon, 9 Jan 2017 17:09:09 -0500 Received: from mga07.intel.com ([134.134.136.100]:14088 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755508AbdAIWJI (ORCPT ); Mon, 9 Jan 2017 17:09:08 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,341,1477983600"; d="scan'208";a="211435146" Date: Tue, 10 Jan 2017 00:09:03 +0200 From: Jarkko Sakkinen To: "Maciej S. Szmigiero" Cc: tpmdd-devel@lists.sourceforge.net, linux-kernel , Peter Huewe , Marcel Selhorst , Christophe Ricard Subject: Re: [RESEND][RFC] tpm_tis: broken on TPMs with a static burst count Message-ID: <20170109220903.vr36mux3nr2bp6z5@intel.com> References: <77221b3a-40b3-f5db-e821-10e258f869dc@maciej.szmigiero.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <77221b3a-40b3-f5db-e821-10e258f869dc@maciej.szmigiero.name> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.6.2-neo (2016-08-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 04, 2017 at 06:47:52PM +0100, Maciej S. Szmigiero wrote: > (Resending as no reply received, this time with CCs to TPM maintainers and > author of the original commit). > > Hi all, > > Commit 1107d065fdf1 (tpm_tis: Introduce intermediate layer for TPM access) > broke TPM support on ThinkPad X61S (and likely also on other machines which > use TPMs with a static burst count). > > It looks like tpm_tis code before this commit had spun on TPM_STS_DATA_AVAIL | > TPM_STS_VALID status bits in the read case and TPM_STS_VALID in the write case > when it got a zero burst count. > > I have attached a patch against current code (linux-tpmdd tree) that brings > back this old behavior. > With this patch the TPM works again on X61S. > However, somebody with more TPM experience should comment whether such behavior > was OK or the change brought by commit 1107d065fdf1 was intentional. > > Maciej Szmigiero For me this commit makes perfect sense. Could you do the following things: 1. Clean up the description a little bit 2. Add your Signed-off-by tag. 3. Add "Cc: stable@vger.kernel.org" tag right after your signed-off-by. 4. CC this linux-security-module@vger.kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org. 5. Run scripts/checkpatch.pl 6. Re-send for review. Thanks for fixing the issue. Keep up the good work! /Jarkko > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index 7993678954a2..72d365db7c61 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -188,7 +188,9 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) > if (rc < 0) > return rc; > burstcnt = get_burstcount(chip); > - if (burstcnt < 0) { > + if (burstcnt == -EBUSY) > + continue; > + else if (burstcnt < 0) { > dev_err(&chip->dev, "Unable to read burstcount\n"); > return burstcnt; > } > @@ -282,18 +284,20 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len) > > while (count < len - 1) { > burstcnt = get_burstcount(chip); > - if (burstcnt < 0) { > + if (burstcnt < 0 && burstcnt != -EBUSY) { > dev_err(&chip->dev, "Unable to read burstcount\n"); > rc = burstcnt; > goto out_err; > + } else if (burstcnt > 0) { > + burstcnt = min_t(int, burstcnt, len - count - 1); > + rc = tpm_tis_write_bytes(priv, > + TPM_DATA_FIFO(priv->locality), > + burstcnt, buf + count); > + if (rc < 0) > + goto out_err; > + > + count += burstcnt; > } > - burstcnt = min_t(int, burstcnt, len - count - 1); > - rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality), > - burstcnt, buf + count); > - if (rc < 0) > - goto out_err; > - > - count += burstcnt; > > if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, > &priv->int_queue, false) < 0) {