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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hans de Goede <hdegoede@redhat.com>,
        Javier Martinez Canillas <javierm@redhat.com>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 034/160] tpm: suppress transmit cmd error logs when TPM 1.2 is disabled/deactivated
Date:   Mon, 19 Nov 2018 17:27:53 +0100
Message-Id: <20181119162634.248839079@linuxfoundation.org>
In-Reply-To: <20181119162630.031306128@linuxfoundation.org>
References: <20181119162630.031306128@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Javier Martinez Canillas <javierm@redhat.com>

[ Upstream commit 0d6d0d62d9505a9816716aa484ebd0b04c795063 ]

For TPM 1.2 chips the system setup utility allows to set the TPM device in
one of the following states:

  * Active: Security chip is functional
  * Inactive: Security chip is visible, but is not functional
  * Disabled: Security chip is hidden and is not functional

When choosing the "Inactive" state, the TPM 1.2 device is enumerated and
registered, but sending TPM commands fail with either TPM_DEACTIVATED or
TPM_DISABLED depending if the firmware deactivated or disabled the TPM.

Since these TPM 1.2 error codes don't have special treatment, inactivating
the TPM leads to a very noisy kernel log buffer that shows messages like
the following:

  tpm_tis 00:05: 1.2 TPM (device-id 0x0, rev-id 78)
  tpm tpm0: A TPM error (6) occurred attempting to read a pcr value
  tpm tpm0: TPM is disabled/deactivated (0x6)
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting to read a pcr value
  ima: No TPM chip found, activating TPM-bypass! (rc=6)
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random

Let's just suppress error log messages for the TPM_{DEACTIVATED,DISABLED}
return codes, since this is expected when the TPM 1.2 is set to Inactive.

In that case the kernel log is cleaner and less confusing for users, i.e:

  tpm_tis 00:05: 1.2 TPM (device-id 0x0, rev-id 78)
  tpm tpm0: TPM is disabled/deactivated (0x6)
  ima: No TPM chip found, activating TPM-bypass! (rc=6)

Reported-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/tpm/tpm-interface.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -415,7 +415,8 @@ ssize_t tpm_transmit_cmd(struct tpm_chip
 	header = cmd;
 
 	err = be32_to_cpu(header->return_code);
-	if (err != 0 && desc)
+	if (err != 0 && err != TPM_ERR_DISABLED && err != TPM_ERR_DEACTIVATED
+	    && desc)
 		dev_err(&chip->dev, "A TPM error (%d) occurred %s\n", err,
 			desc);