tpm_tis: Fix check_locality for correct locality acquisition
authorJames Bottomley <James.Bottomley@HansenPartnership.com>
Thu, 1 Oct 2020 18:09:21 +0000 (11:09 -0700)
committerJarkko Sakkinen <jarkko@kernel.org>
Tue, 16 Feb 2021 08:40:27 +0000 (10:40 +0200)
commit3d9ae54af1d02a7c0edc55c77d7df2b921e58a87
tree2648fd4b1e3d42d6a933d83c37b677f9b40d7068
parentf40ddce88593482919761f74910f42f4b84c004b
tpm_tis: Fix check_locality for correct locality acquisition

The TPM TIS specification says the TPM signals the acquisition of locality
when the TMP_ACCESS_REQUEST_USE bit goes to one *and* the
TPM_ACCESS_REQUEST_USE bit goes to zero.  Currently we only check the
former not the latter, so check both.  Adding the check on
TPM_ACCESS_REQUEST_USE should fix the case where the locality is
re-requested before the TPM has released it.  In this case the locality may
get released briefly before it is reacquired, which causes all sorts of
problems. However, with the added check, TPM_ACCESS_REQUEST_USE should
remain 1 until the second request for the locality is granted.

Cc: stable@ger.kernel.org
Fixes: 27084efee0c3 ("[PATCH] tpm: driver for next generation TPM chips")
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
drivers/char/tpm/tpm_tis_core.c