Re: [PATCH v4 02/26] arm64: cpufeature: Add cpufeature for IRQ priority masking

[Julien Thierry]

On 25/05/18 11:04, Suzuki K Poulose wrote:
> On 25/05/18 10:49, Julien Thierry wrote:
> > Add a cpufeature indicating whether a cpu supports masking interrupts
> > by priority.
>
> How is this different from the SYSREG_GIC_CPUIF cap ? Is it just
> the description ?

More or less.

It is just to have an easier condition in the rest of the series. 
Basically the PRIO masking feature is enabled if we have a GICv3 CPUIF 
working *and* the option was selected at build time. Before this meant 
that I was checking for the GIC_CPUIF cap inside #ifdefs (and putting 
alternatives depending on that inside #ifdefs as well).

Having this as a separate feature feels easier to manage in the code. It 
also makes it clearer at boot time that the kernel will be using irq 
priorities (although I admit it was not the initial intention):

[    0.000000] CPU features: detected: IRQ priority masking


But yes that new feature will be detected only if SYSREG_GIC_CPUIF gets 
detected as well.

Cheers,

--
Julien Thierry