On Wed, Feb 21, 2018 at 12:53:47AM +0200, Jarkko Sakkinen wrote: > From: Alexander Steffen <Alexander.Steffen@xxxxxxxxxxxx> > > 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@xxxxxxxxxxxx> > Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkine@xxxxxxxxxxxxxxx> > Fixes: 2482b1bba5122b1d5516c909832bdd282015b8e9 > --- > v4: Some updatees from jarkko.sakkinen@xxxxxxxxxxxxxxx: > - squashed tpm_buf migration > - cleaned up a bunch of clutter from the original patch I decided to rather just clean up the code. Would have taken more time to explain than do the code change. Hope you don't mind and hope I didn't break it. /Jarkko
