Skip to content
Commit 5e3a3f27 authored by Stefan Mahnke-Hartmann's avatar Stefan Mahnke-Hartmann Committed by Jarkko Sakkinen
Browse files

tpm: Add upgrade/reduced mode support for TPM1.2 modules



In case a TPM in failure mode is detected, the TPM should be accessible
through a transparent communication channel for analysing purposes (e.g.
TPM_GetTestResult) or a field upgrade. Since a TPM in failure mode has
similar reduced functionality as in field upgrade mode, the flag
TPM_CHIP_FLAG_FIRMWARE_UPGRADE is also valid.

As described in TCG TPM Main Part1 Design Principles, Revision 116,
chapter 9.2.1. the TPM also allows an update function in case a TPM is
in failure mode.

If the TPM in failure mode is detected, the function tpm1_auto_startup()
sets TPM_CHIP_FLAG_FIRMWARE_UPGRADE flag, which is used later during
driver initialization/deinitialization to disable functionality which
makes no sense or will fail in the current TPM state. The following
functionality is affected:
 * Do not register TPM as a hwrng
 * Do not get pcr allocation
 * Do not register sysfs entries which provide information impossible to
   obtain in limited mode

Signed-off-by: default avatarStefan Mahnke-Hartmann <stefan.mahnke-hartmann@infineon.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent 200e340f
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment