From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751881AbcG1Ww5 (ORCPT ); Thu, 28 Jul 2016 18:52:57 -0400 Received: from mail-pa0-f54.google.com ([209.85.220.54]:33341 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751438AbcG1Wwy (ORCPT ); Thu, 28 Jul 2016 18:52:54 -0400 Date: Thu, 28 Jul 2016 15:52:50 -0700 From: Dmitry Torokhov To: Andrey Pronin Cc: Jarkko Sakkinen , Peter Huewe , Marcel Selhorst , Jason Gunthorpe , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Christophe Ricard , smbarber@chromium.org, dianders@chromium.org Subject: Re: [PATCH v3 1/2] tpm_tis_core: add optional max xfer size check Message-ID: <20160728225250.GA28623@dtor-ws> References: <1468546745-14646-1-git-send-email-apronin@chromium.org> <1469677797-74304-2-git-send-email-apronin@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1469677797-74304-2-git-send-email-apronin@chromium.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 27, 2016 at 08:49:56PM -0700, Andrey Pronin wrote: > If tpm reports a bigger burstcnt than allowed by the physical protocol, > set burstcnt to the max allowed value. > > In practice, seen in case of xfer issues (e.g. in spi interface case, > lost header causing flow control issues and wrong values returned on read > from TPM_STS). Without catching, causes the physical layer to reject xfer. > > Signed-off-by: Andrey Pronin > --- > drivers/char/tpm/tpm_tis_core.c | 9 ++++++++- > drivers/char/tpm/tpm_tis_core.h | 1 + > 2 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index f22caf8..7c4fa0c 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -168,8 +168,15 @@ static int get_burstcount(struct tpm_chip *chip) > return rc; > > burstcnt = (value >> 8) & 0xFFFF; > - if (burstcnt) > + if (burstcnt) { > + if (priv->phy_ops->max_xfer_size && > + (burstcnt > priv->phy_ops->max_xfer_size)) { This does not actually need parentheses, otehrwise: Reviewed-by: Dmitry Torokhov > + dev_warn(&chip->dev, > + "Bad burstcnt read: %d\n", burstcnt); > + burstcnt = priv->phy_ops->max_xfer_size; > + } > return burstcnt; > + } > msleep(TPM_TIMEOUT); > } while (time_before(jiffies, stop)); > return -EBUSY; > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > index 9191aab..58e8b14 100644 > --- a/drivers/char/tpm/tpm_tis_core.h > +++ b/drivers/char/tpm/tpm_tis_core.h > @@ -102,6 +102,7 @@ struct tpm_tis_phy_ops { > int (*read16)(struct tpm_tis_data *data, u32 addr, u16 *result); > int (*read32)(struct tpm_tis_data *data, u32 addr, u32 *result); > int (*write32)(struct tpm_tis_data *data, u32 addr, u32 src); > + u16 max_xfer_size; > }; > > static inline int tpm_tis_read_bytes(struct tpm_tis_data *data, u32 addr, > -- > 2.6.6 > -- Dmitry