From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from the.earth.li (the.earth.li [93.93.131.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F4C123E25B; Fri, 7 Mar 2025 16:36:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.93.131.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741365386; cv=none; b=VvrmjOE8Lf6TQfjqgPCwT3IyNYzx3mX9Kb57rgCtLydXJrp2VxYv4FfoZns0UyJ9UX7P3osucHXkQ6OJ58OmJLWXXKin3d9GuXyYHoKxzjeCPp5H30HGB/wIqFMVWY4spIFIEaOyi35sZUKplmUTmWQgvBW7l2nW8/8uXrvc5t4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741365386; c=relaxed/simple; bh=r498hqc3k8IbNvDyqnT6t8TEmkwx9aSVtSm88FQLOWA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HEuhz5jJPaC3QJAlPPvhQ1AN6sE8LKgLeUpHX+h1BGraJCpeqZhEvm5SA40mg4colxjVG1dwSFoiJ94qqTI6SwS8yl16VtRPymLjKOM3EBJRavLTECUWG/5h2YG3CB7CvzC1ZFUNzQLUcHnBrS/qvlYdTUhTRn1rONcn0kij4NQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=earth.li; spf=pass smtp.mailfrom=earth.li; dkim=pass (2048-bit key) header.d=earth.li header.i=@earth.li header.b=UHtIc06O; arc=none smtp.client-ip=93.93.131.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=earth.li Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=earth.li Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=earth.li header.i=@earth.li header.b="UHtIc06O" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=earth.li; s=the; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject: Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=VX3FZVvlkaPBR2WEHi1SCf1gBH/UKqgWJH5Ig5wpJpM=; b=UHtIc06OH7aS1gGS6P3gebuMW2 zhYKRqgWR6Lhf3ZUdGjiMWUXgRaVyC+h4D1CdrvorggSGtG4wlCVw9duaPKe51JnglEc6zYuGj8Fb LC5ArjgSRKz5xZAA2+7mv6PVdeqS8r7eeolTE8d+/9scw0bZ9KFT3vMrMRaxpe3AxCjNA/SBcp9Xn /yWIoxEK7E4tEhFii3CTNUGvLVYOSgDB71j7E0BQFRySrp/1HG5s6xtl6r15dixLJ70vm2YYAN8Pb PvUtomE5bdg93GN/KhdjznJuyRz4SznTN5pbkEfGOwlL1erBRwT8wNJxWBm6nR9xLw4lGAIQHdzbJ jRTX30iA==; Received: from noodles by the.earth.li with local (Exim 4.96) (envelope-from ) id 1tqagG-00DC2U-05; Fri, 07 Mar 2025 16:36:12 +0000 Date: Fri, 7 Mar 2025 16:36:12 +0000 From: Jonathan McDowell To: Jarkko Sakkinen Cc: Peter Huewe , Jason Gunthorpe , James Bottomley , Stefan Berger , linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] tpm, tpm_tis: Workaround failed command reception on Infineon devices Message-ID: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Mar 07, 2025 at 12:23:11AM +0200, Jarkko Sakkinen wrote: > On Thu, Mar 06, 2025 at 09:00:56AM +0000, Jonathan McDowell wrote: > > From: Jonathan McDowell > > > > Some Infineon devices have a issue where the status register will get > > stuck with a quick REQUEST_USE / COMMAND_READY sequence. This is not > > simply a matter of requiring a longer timeout; the work around is to > > retry the command submission. Add appropriate logic to do this in the > > send path. > > > > This is fixed in later firmware revisions, but those are not always > > available, and cannot generally be easily updated from outside a > > firmware environment. > > > > Testing has been performed with a simple repeated loop of doing a > > TPM2_CC_GET_CAPABILITY for TPM_CAP_PROP_MANUFACTURER using the Go code > > at: > > > > https://the.earth.li/~noodles/tpm-stuff/timeout-reproducer-simple.go > > > > It can take several hours to reproduce, and millions of operations. > > > > Signed-off-by: Jonathan McDowell > > --- > > drivers/char/tpm/tpm_tis_core.c | 17 ++++++++++++++--- > > drivers/char/tpm/tpm_tis_core.h | 1 + > > include/linux/tpm.h | 1 + > > 3 files changed, 16 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > > index 167d71747666..e4eae206a353 100644 > > --- a/drivers/char/tpm/tpm_tis_core.c > > +++ b/drivers/char/tpm/tpm_tis_core.c > > @@ -464,7 +464,10 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) > > > > if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, > > &priv->int_queue, false) < 0) { > > - rc = -ETIME; > > + if (test_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags)) > > + rc = -EAGAIN; > > + else > > + rc = -ETIME; > > goto out_err; > > } > > status = tpm_tis_status(chip); > > @@ -481,7 +484,10 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) > > > > if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, > > &priv->int_queue, false) < 0) { > > - rc = -ETIME; > > + if (test_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags)) > > + rc = -EAGAIN; > > + else > > + rc = -ETIME; > > I'd encapsulate this inside wait_for_tpm_stat(). I think that gets a bit more complicated; this is an errata in the send command path, for a stuck VALID bit, and the fix is to restart the whole command send (i.e. we need to kick the TPM with tpm_tis_ready() etc). I'm not sure returning EAGAIN in wait_for_tpm_stat() then makes tpm_tis_send_data() any simpler. > > goto out_err; > > } > > status = tpm_tis_status(chip); > > @@ -546,9 +552,11 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len) > > if (rc >= 0) > > /* Data transfer done successfully */ > > break; > > - else if (rc != -EIO) > > + else if (rc != EAGAIN && rc != -EIO) > > /* Data transfer failed, not recoverable */ > > return rc; > > + > > + usleep_range(priv->timeout_min, priv->timeout_max); > > } > > > > /* go and do it */ > > @@ -1144,6 +1152,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > > priv->timeout_max = TIS_TIMEOUT_MAX_ATML; > > } > > > > + if (priv->manufacturer_id == TPM_VID_IFX) > > + set_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags); > > + > > if (is_bsw()) { > > priv->ilb_base_addr = ioremap(INTEL_LEGACY_BLK_BASE_ADDR, > > ILB_REMAP_SIZE); > > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > > index 690ad8e9b731..ce97b58dc005 100644 > > --- a/drivers/char/tpm/tpm_tis_core.h > > +++ b/drivers/char/tpm/tpm_tis_core.h > > @@ -89,6 +89,7 @@ enum tpm_tis_flags { > > TPM_TIS_INVALID_STATUS = 1, > > TPM_TIS_DEFAULT_CANCELLATION = 2, > > TPM_TIS_IRQ_TESTED = 3, > > + TPM_TIS_STATUS_WORKAROUND = 4, > > TPM_TIS_TIMEOUT_AGAIN or maybe *_REPEAT? The current name does > not tell anything. Yeah, TPM_TIS_STATUS_VALID_RETRY is perhaps clearer; it's not a timeout, and we're looking to do a retry based on STS_VALID. > > }; > > > > struct tpm_tis_data { > > diff --git a/include/linux/tpm.h b/include/linux/tpm.h > > index 20a40ade8030..6c3125300c00 100644 > > --- a/include/linux/tpm.h > > +++ b/include/linux/tpm.h > > @@ -335,6 +335,7 @@ enum tpm2_cc_attrs { > > #define TPM_VID_WINBOND 0x1050 > > #define TPM_VID_STM 0x104A > > #define TPM_VID_ATML 0x1114 > > +#define TPM_VID_IFX 0x15D1 > > > > enum tpm_chip_flags { > > TPM_CHIP_FLAG_BOOTSTRAPPED = BIT(0), J. -- ... "What's the philosophical difference between a killfile and the automoderation?" "A killfile throws away good posts. Automoderation throws away bad posts." -- Jonathan H N Chin to Calle Dybedahl