Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752801AbcJKMBQ (ORCPT ); Tue, 11 Oct 2016 08:01:16 -0400 Received: from mga07.intel.com ([134.134.136.100]:64511 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752583AbcJKMBO (ORCPT ); Tue, 11 Oct 2016 08:01:14 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,329,1473145200"; d="scan'208";a="888856482" From: Jarkko Sakkinen To: tpmdd-devel@lists.sourceforge.net Cc: Peter Huewe , Jarkko Sakkinen , Marcel Selhorst , Jason Gunthorpe , linux-kernel@vger.kernel.org (open list) Subject: [PATCH] char/tpm: Check return code of wait_for_tpm_stat Date: Tue, 11 Oct 2016 15:01:01 +0300 Message-Id: <1476187261-29027-1-git-send-email-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2962 Lines: 83 From: Peter Huewe In some weird cases it might be possible that the TPM does not set STS.VALID within the given timeout time (or ever) but sets STS.EXPECT (STS=0x0C) In this case the driver gets stuck in the while loop of tpm_tis_send_data and loops endlessly. Checking the return value of wait_for_tpm_stat fixes this and the driver bails out correctly. While at it fixing all other users since if the TPM does not manage to set STS.VALID within the reasonable timeframe something is definitely wrong and the driver should react correctly. Signed-off-by: Peter Huewe Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm_tis_core.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index e3bf31b..73f4c4b 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -180,11 +180,13 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); int size = 0, burstcnt, rc; - while (size < count && - wait_for_tpm_stat(chip, + while (size < count) { + rc = wait_for_tpm_stat(chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID, chip->timeout_c, - &priv->read_queue, true) == 0) { + &priv->read_queue, true); + if (rc < 0) + return rc; burstcnt = min_t(int, get_burstcount(chip), count - size); rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality), @@ -229,8 +231,11 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) goto out; } - wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, - &priv->int_queue, false); + if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, + &priv->int_queue, false) < 0) { + size = -ETIME; + goto out; + } status = tpm_tis_status(chip); if (status & TPM_STS_DATA_AVAIL) { /* retry? */ dev_err(&chip->dev, "Error left over data\n"); @@ -279,8 +284,11 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len) count += burstcnt; - wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, - &priv->int_queue, false); + if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, + &priv->int_queue, false) < 0) { + rc = -ETIME; + goto out_err; + } status = tpm_tis_status(chip); if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) { rc = -EIO; @@ -293,8 +301,11 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len) if (rc < 0) goto out_err; - wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, - &priv->int_queue, false); + if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, + &priv->int_queue, false) < 0) { + rc = -ETIME; + goto out_err; + } status = tpm_tis_status(chip); if (!itpm && (status & TPM_STS_DATA_EXPECT) != 0) { rc = -EIO; -- 2.7.4