[U-Boot] [PATCH v1] colibri_imx7: boot kernel in secure mode

[Igor Opaniuk]

Hi Tobias,

On Wed, Jul 10, 2019 at 3:35 PM Tobias Junghans
<tobias.junghans at veyon.io> wrote:
>
> > > NXP downstream kernel uses legacy method to enable other cores,
> > > which requires kernel to run in a security mode (althought upstream
> > > kernel
> > > uses PSCI for this).
> > >
> > > As we're using NXP kernel in our BSPs, lets enable this by default.
> > >
> > > Signed-off-by: Igor Opaniuk <igor.opaniuk at toradex.com>
>
> How does enabling both cores work in upstream kernel? It looks like PSCI does
> not work in secure mode using mainline 4.19 LTS kernel. Any hints? Until this
> is resolved booting in secure mode per default IMHO is not a good option.
>
> Best regards
>
> Tobias
>
>

I'm afraid you're right.
Just after a bit of time researching and discussing with Stefan, seems
that we need to introduce two different wrappers for booting the
mainline kernel and downstream NXP kernel.

* NXP kernel has legacy code to enable all cores, which works only when
running in secure mode.
* Mainline kernel, as you said before, does use PSCI for this, which
is provided by U-boot (which adds proper psci nodes to the linux
dtb on-fly before transferring control to the linux kernel entry point). When we
try to load it in secure mode, it continues running on the same Secure PL1,
and communication using SMC calling convention doesn't make sense at this case.

-- 
Best regards - Freundliche Grüsse - Meilleures salutations

Igor Opaniuk

mailto: igor.opaniuk at gmail.com
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