Re: [PATCH] firmware/psci: Don't register with debugfs if PSCI isn't available

[Dmitry Baryshkov]

On 05/01/2023 11:08, Marc Zyngier wrote:
> Contrary to popular belief, PSCI is not a universal property of an
> ARM/arm64 system. There is a garden variety of systems out there
> that don't (or even cannot) implement it.
>
> I'm the first one deplore such a situation, but hey...
>
> On such systems, a "cat /sys/kernel/debug/psci" results in
> fireworks, as no invocation callback is registered.
>
> Check for the invoke_psci_fn and psci_ops.get_version pointers
> before registering with the debugfs subsystem, avoiding the
> issue altogether.
>
> Fixes: 3137f2e60098 ("firmware/psci: Add debugfs support to ease debugging")
> Reported-by: Hector Martin <marcan@xxxxxxxxx>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> Cc: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>

Acked-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>

--
With best wishes
Dmitry