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SubjectRe: [PATCH] tpm: suppress transmit cmd error logs when TPM 1.2 is disabled/deactivated
On Thu, Aug 30, 2018 at 04:40:05PM +0200, Javier Martinez Canillas wrote:
> 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>
>
> ---
>
> drivers/char/tpm/tpm-interface.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 1a803b0cf98..9f61106502a 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -663,7 +663,8 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
> return len;
>
> 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);
> if (err)
> --
> 2.17.1
>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

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