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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Marc Zyngier <maz@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: Hector Martin <marcan@marcan.st>, Mark Brown <broonie@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Mark Rutland <mark.rutland@arm.com>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>
Subject: Re: [PATCH] firmware/psci: Don't register with debugfs if PSCI isn't available
Date: Thu, 5 Jan 2023 15:13:59 +0200	[thread overview]
Message-ID: <08679155-5b27-f2a9-522c-0a63a3525dc0@linaro.org> (raw)
In-Reply-To: <20230105090834.630238-1-maz@kernel.org>

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@marcan.st>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>

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

-- 
With best wishes
Dmitry


  parent reply	other threads:[~2023-01-05 13:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-05  9:08 [PATCH] firmware/psci: Don't register with debugfs if PSCI isn't available Marc Zyngier
2023-01-05 13:08 ` Mark Rutland
2023-01-05 13:13 ` Dmitry Baryshkov [this message]
2023-01-05 22:56 ` Hector Martin
2023-01-06 17:50 ` Will Deacon

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