Message-ID: <7850c6f4-6a6f-4934-895d-9ec0688cda2a@foss.st.com>
Date: Mon, 9 Jun 2025 18:30:07 +0200
From: Arnaud POULIQUEN <arnaud.pouliquen@...s.st.com>
To: Mathieu Poirier <mathieu.poirier@...aro.org>
CC: Bjorn Andersson <andersson@...nel.org>,
        Jens Wiklander
	<jens.wiklander@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        "Krzysztof
 Kozlowski" <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <op-tee@...ts.trustedfirmware.org>, <devicetree@...r.kernel.org>
Subject: Re: [RESEND PATCH v16 0/6] Introduction of a remoteproc tee to load
 signed firmware

Hello Mathieu,

On 6/9/25 17:23, Mathieu Poirier wrote:
> On Tue, Jun 03, 2025 at 12:08:02PM +0200, Arnaud Pouliquen wrote:
>> Hello Bjorn and Mathieu,
>>
>> I am resending this series after waiting for over two months for Bjorn's
>> feedback, despite a prior reminder.
>>
>> Please could you coordinate between yourselves to determine who will continue
>> reviewing this series? It would be greatly appreciated if the review could
>> proceed within a more reasonable timeframe.
>>
>> Thanks in advance and best regards,
>> Arnaud
>>
>>
>> Main updates from version V15[1]:
>> - Removed the rproc_ops:load_fw() operation introduced in the previous version.
>> - Returned to managing the remoteproc firmware loading in rproc_tee_parse_fw to
>>   load and authenticate the firmware before getting the resource table.
>> - Added spinlock and dev_link mechanisms in remoteproc TEE to better manage
>>   bind/unbind.
>>
> 
> Have all pending issues been resolved or is there still questions about some
> aspects of the design?
>  

No pending issues on my side.

In terms of design, I resend an equivalent of the V13 design incorporating
Bjorn's comments on V15.
The pending questions are:
- is that V13/V16 is aligned with Bjorn's expectations[1].
- are you also aligned on this design even if you proposed an alternative that
  implemented in V14 and V15
Few details on the V13/V16 design:

The main point of discussion is the rproc_tee_parse_fw() implementation.
In V13, this function loaded the firmware and then parses the resource table.

You proposed an alternative, to add a new rproc->load ops
in the remoteproc core instead (implemented in V14 and V15).
Bjorn expressed concerns about this and proposed a solution that, from my
understanding, is equivalent to the V13 implementation.

Thanks,
Arnaud


[1] https://lkml.org/lkml/2025/3/5/906

>> More details are available in each patch commit message.
>>
>> [1] https://lore.kernel.org/linux-remoteproc/20241128084219.2159197-7-arnaud.pouliquen@foss.st.com/T/
>>
>> Tested-on: commit 0ff41df1cb26 ("Linux 6.15")
>>
>> Description of the feature:
>> --------------------------
>> 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 (6):
>>   remoteproc: core: Introduce rproc_pa_to_va helper
>>   remoteproc: Add TEE support
>>   remoteproc: Introduce release_fw optional operation
>>   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   |  58 +-
>>  drivers/remoteproc/Kconfig                    |  10 +
>>  drivers/remoteproc/Makefile                   |   1 +
>>  drivers/remoteproc/remoteproc_core.c          |  52 ++
>>  drivers/remoteproc/remoteproc_internal.h      |   6 +
>>  drivers/remoteproc/remoteproc_tee.c           | 619 ++++++++++++++++++
>>  drivers/remoteproc/stm32_rproc.c              | 139 +++-
>>  include/linux/remoteproc.h                    |   4 +
>>  include/linux/remoteproc_tee.h                |  90 +++
>>  9 files changed, 935 insertions(+), 44 deletions(-)
>>  create mode 100644 drivers/remoteproc/remoteproc_tee.c
>>  create mode 100644 include/linux/remoteproc_tee.h
>>
>>
>> base-commit: 0ff41df1cb268fc69e703a08a57ee14ae967d0ca
>> -- 
>> 2.25.1
>>

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