[PATCH 0/4] Introduction of a remoteproc tee to load signed firmware

From: Arnaud Pouliquen
Date: Mon Jan 15 2024 - 08:54:27 EST


This series proposes the implementation of a remoteproc tee driver to
communicate with a TEE trusted application responsible for authenticating and
loading the remoteproc firmware image in an Arm secure context.

1) Principle:

The remoteproc tee driver provides services to communicate with the OP-TEE
trusted application running on the Trusted Execution Context (TEE).
The trusted application in TEE manages the remote processor lifecycle:

- authenticating and loading firmware images,
- isolating and securing the remote processor memories,
- supporting multi-firmware (e.g., TF-M + Zephyr on a Cortex-M33),
- managing the start and stop of the firmware by the TEE.

2) Format of the signed image:

Refer to:
https://github.com/OP-TEE/optee_os/blob/master/ta/remoteproc/src/remoteproc_core.c#L18-L57

3) OP-TEE trusted application API:

Refer to:
https://github.com/OP-TEE/optee_os/blob/master/ta/remoteproc/include/ta_remoteproc.h

4) OP-TEE signature script

Refer to:
https://github.com/OP-TEE/optee_os/blob/master/scripts/sign_rproc_fw.py

Example of usage:
sign_rproc_fw.py --in <fw1.elf> --in <fw2.elf> --out <signed_fw.sign> --key ${OP-TEE_PATH}/keys/default.pem


5) Impact on User space Application

No sysfs impact.the user only needs to provide the signed firmware image
instead of the ELF image.


For more information about the implementation, a presentation is available here
(note that the format of the signed image has evolved between the presentation
and the integration in OP-TEE).

https://resources.linaro.org/en/resource/6c5bGvZwUAjX56fvxthxds


Arnaud Pouliquen (4):
remoteproc: Add TEE support
dt-bindings: remoteproc: add compatibility for TEE support
remoteproc: stm32: create sub-functions to request shutdown and
release
remoteproc: stm32: Add support of an OP-TEE TA to load the firmware

.../bindings/remoteproc/st,stm32-rproc.yaml | 53 ++-
drivers/remoteproc/Kconfig | 10 +
drivers/remoteproc/Makefile | 1 +
drivers/remoteproc/stm32_rproc.c | 233 +++++++++--
drivers/remoteproc/tee_remoteproc.c | 393 ++++++++++++++++++
include/linux/tee_remoteproc.h | 99 +++++
6 files changed, 742 insertions(+), 47 deletions(-)
create mode 100644 drivers/remoteproc/tee_remoteproc.c
create mode 100644 include/linux/tee_remoteproc.h

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2.25.1