Messages in this thread | | | Date | Wed, 21 Feb 2018 09:31:32 +0200 | From | Jarkko Sakkinen <> | Subject | Re: [PATCH v4] tpm: Trigger only missing TPM 2.0 self tests |
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On Wed, Feb 21, 2018 at 12:53:47AM +0200, Jarkko Sakkinen wrote: > From: Alexander Steffen <Alexander.Steffen@infineon.com> > > My Nuvoton 6xx in a Dell XPS-13 has been intermittently failing to work > (necessitating a reboot). The problem seems to be that the TPM gets into a > state where the partial self-test doesn't return TPM_RC_SUCCESS (meaning > all tests have run to completion), but instead returns TPM_RC_TESTING > (meaning some tests are still running in the background). There are > various theories that resending the self-test command actually causes the > tests to restart and thus triggers more TPM_RC_TESTING returns until the > timeout is exceeded. > > There are several issues here: firstly being we shouldn't slow down the > boot sequence waiting for the self test to complete once the TPM > backgrounds them. It will actually make available all functions that have > passed and if it gets a failure return TPM_RC_FAILURE to every subsequent > command. So the fix is to kick off self tests once and if they return > TPM_RC_TESTING log that as a backgrounded self test and continue on. In > order to prevent other tpm users from seeing any TPM_RC_TESTING returns > (which it might if they send a command that needs a TPM subsystem which is > still under test), we loop in tpm_transmit_cmd until either a timeout or we > don't get a TPM_RC_TESTING return. > > Finally, there have been observations of strange returns from a partial > test. One Nuvoton is occasionally returning TPM_RC_COMMAND_CODE, so treat > any unexpected return from a partial self test as an indication we need to > run a full self test. > > Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> > Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com> > Fixes: 2482b1bba5122b1d5516c909832bdd282015b8e9
Fixes tag is in wrong format. Should be 12 characters of the hash and short summary in parentheses:
Fixes: 2482b1bba512 ("tpm: Trigger only missing TPM 2.0 self tests")
/Jarkko
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