tpm: suppress transmit cmd error logs when TPM 1.2 is disabled/deactivated

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 <[email protected]>

Signed-off-by Javier Martinez Canillas <[email protected]>

---

 drivers/char/tpm/tpm-interface.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

drivers/char/tpm/tpm-interface.c +2 -1

index 1a803b0cf98..9f61106502a 100644
@@ -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)

Signature · 1 line

2.17.1