+ Jens Hi Stuart, On Tue, 11 Feb 2025 at 04:52, Stuart Yoder <stuart.yoder@xxxxxxx> wrote: > > These patches add support for the CRB FF-A start method defined > in the TCG ACPI specification v1.4 and the FF-A ABI defined > in the Arm TPM Service CRB over FF-A (DEN0138) specification. > (https://developer.arm.com/documentation/den0138/latest/) Nice to have a specification standardizing interface to TPM managed/implemented by the firmware. Care to add corresponding kernel documentation under Documentation/security/tpm/. BTW, we already have drivers/char/tpm/tpm_ftpm_tee.c, so do you see possibilities for an abstraction layer on top of communication channel based on either FF-A or TEE or platform bus? > > FF-A is a messaging framework for Arm-based systems and in the > context of the TPM driver is used to signal 'start' to a CRB-based > TPM service which is hosted in an FF-A secure partition running in > TrustZone. Is there any open source implementation for such a secure partition managing the TPM? Also, is that really a discrete TPM or firmware TPM managed by the firmware? If it supports firmware TPM, I would be interested to see how you plan to handle cases related to secure storage. -Sumit > > The first patch adds an FF-A driver to handle the FF-A messaging when > communicating with a CRB-based TPM secure partition built on FF-A. > The driver is probed when the TPM secure partition is discovered by > the Linux FF-A infrastructure. > > The second patch consolidates the check for idle support in the CRB > driver to one place. > > The third patch defines the new ACPI start method enumeration for > CRB over FF-A. > > The fourth patch adds support for the FF-A ACPI start method to > the TPM crb driver. > > Stuart Yoder (4): > tpm_crb: implement driver compliant to CRB over FF-A > tpm_crb: refactor check for idle support into TPM into inline function > ACPICA: add start method for Arm FF-A > tpm_crb: add support for the Arm FF-A start method > > drivers/char/tpm/Kconfig | 9 ++ > drivers/char/tpm/Makefile | 1 + > drivers/char/tpm/ffa_crb.c | 310 +++++++++++++++++++++++++++++++++++++ > drivers/char/tpm/ffa_crb.h | 30 ++++ > drivers/char/tpm/tpm_crb.c | 81 +++++++++- > include/acpi/actbl3.h | 1 + > 6 files changed, 426 insertions(+), 6 deletions(-) > create mode 100644 drivers/char/tpm/ffa_crb.c > create mode 100644 drivers/char/tpm/ffa_crb.h > > -- > 2.34.1 > >
