linux-kernel - Re: [PATCH v5 3/3] efi: Add tee-based EFI variable driver

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Message-ID: <CAC_iWj+cP4RfDNu_n-ZOp7A62W34drLpPszN_hrkqF_aPTLtMg@mail.gmail.com>
Date:   Wed, 7 Jun 2023 21:17:52 +0300
From:   Ilias Apalodimas <ilias.apalodimas@...aro.org>
To:     Jan Kiszka <jan.kiszka@...mens.com>
Cc:     Sumit Garg <sumit.garg@...aro.org>,
        Ard Biesheuvel <ardb@...nel.org>,
        Masahisa Kojima <masahisa.kojima@...aro.org>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        linux-kernel@...r.kernel.org, op-tee@...ts.trustedfirmware.org,
        Johan Hovold <johan+linaro@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        linux-efi@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org,
        "Su, Bao Cheng (RC-CN DF FA R&D)" <baocheng.su@...mens.com>
Subject: Re: [PATCH v5 3/3] efi: Add tee-based EFI variable driver

On Wed, 7 Jun 2023 at 20:14, Jan Kiszka <jan.kiszka@...mens.com> wrote:
>
> On 07.06.23 18:59, Ilias Apalodimas wrote:
> > On Wed, 7 Jun 2023 at 19:09, Ilias Apalodimas
> > <ilias.apalodimas@...aro.org> wrote:
> >>
> >> Hi Jan,
> >>
> >> [...]
> >>>>>> No I don't, this will work reliably without the need to remount the efivarfs.
> >>>>>> As you point out you will still have this dependency if you end up
> >>>>>> building them as modules and you manage to mount the efivarfs before
> >>>>>> those get inserted.  Does anyone see a reasonable workaround?
> >>>>>> Deceiving the kernel and making the bootloader set the RT property bit
> >>>>>> to force the filesystem being mounted as rw is a nasty hack that we
> >>>>>> should avoid.  Maybe adding a kernel command line parameter that says
> >>>>>> "Ignore the RTPROP I know what I am doing"?  I don't particularly love
> >>>>>> this either, but it's not unreasonable.
> >>>>>
> >>>>> In the context of https://github.com/OP-TEE/optee_os/issues/6094,
> >>>>> basically this issue mapped on reboot/shutdown, I would really love to
> >>>>> see the unhandy tee-supplicant daemon to be overcome.
> >>>>
> >>>> I have seen this error before and it has been on my todo list. So I
> >>>> have tried to fix it here [1]. Feel free to test it and let me know if
> >>>> you see any further issues.
> >>>>
> >>>> [1] https://lkml.org/lkml/2023/6/7/927
> >>>>
> >>>
> >>> Ah, nice, will test ASAP!
> >>>
> >>> Meanwhile more food: I managed to build a firmware that was missing
> >>> STMM. But the driver loaded, and I got this:
> >>
> >> Thanks for the testing. I'll try to reproduce it locally and get back to you
> >
> > Can you provide a bit more info on how that was triggered btw? I would
> > be helpful to know
> >
> > - OP-TEE version
>
> Today's master, 145953d55.
>
> > - was it compiled as a module or built-in?
>
> Sorry, not sure anymore, switching back and forth right now. I think it
> was built-in.
>
> > - was the supplicant running?
>
> Yes.
>

Ok thanks, that helps.  I guess this also means U-Boot was compiled to
store the variables in a file in the ESP instead of the RPMB right?
Otherwise, I can't see how the device booted in the first place.

Thanks
/Ilias


> Jan
>
> --
> Siemens AG, Technology
> Competence Center Embedded Linux
>