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SubjectRe: [PATCH v3 1/5] arch_topology: validate input frequencies to arch_set_freq_scale()
On 24-08-20, 22:02, Ionela Voinescu wrote:
> The current frequency passed to arch_set_freq_scale() could end up
> being 0, signaling an error in setting a new frequency. Also, if the
> maximum frequency in 0, this will result in a division by 0 error.
>
> Therefore, validate these input values before using them for the
> setting of the frequency scale factor.
>
> Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
> ---
> drivers/base/arch_topology.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index 75f72d684294..1aca82fcceb8 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c
> @@ -33,6 +33,9 @@ void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
> unsigned long scale;
> int i;
>
> + if (!cur_freq || !max_freq)

We should probably use unlikely() here.

Rafael: Shouldn't this have a WARN_ON_ONCE() as well ?

> + return;
> +
> /*
> * If the use of counters for FIE is enabled, just return as we don't
> * want to update the scale factor with information from CPUFREQ.
> --
> 2.17.1

--
viresh

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