Re: [PATCH v2 16/20] arm64: Handle shared capability entries

[Suzuki K Poulose]

On 08/02/18 12:04, Dave Martin wrote:
> On Wed, Jan 31, 2018 at 06:28:03PM +0000, Suzuki K Poulose wrote:
> > Some capabilities have different criteria for detection and associated
> > actions based on the matching criteria, even though they all share the
> > same capability bit. So far we have used multiple entries with the same
> > capability bit to handle this. This is prone to errors, as the
> > cpu_enable is invoked for each entry, irrespective of whether the
> > detection rule applies to the CPU or not. And also this complicates
> > other helpers, e.g, __this_cpu_has_cap.
> >
> > This patch adds a wrapper entry to cover all the possible variations
> > of a capability and ensures :
> >   1) The capabilitiy is set when at least one of the entry detects
> >   2) Action is only taken for the entries that detects.
> >
> > This avoids explicit checks in the call backs. The only constraint
> > here is that, all the entries should have the same "type".
> >
> > Cc: Dave Martin <dave.martin@xxxxxxx>
> > Cc: Will Deacon <will.deacon@xxxxxxx>
> > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > ---
>
> [...]
>
> > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
>
> [...]
>
> > @@ -1275,7 +1274,7 @@ static bool __verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_li
> >   		if (!(caps->type & scope_mask))
> >   			continue;
> >   
> > -		cpu_has_cap = __this_cpu_has_cap(caps_list, caps->capability);
> > +		cpu_has_cap = caps->matches(caps, SCOPE_LOCAL_CPU);
>
> One other minor thing: the original caps_list argument seems no longer
> to be needed in this function after this change.
>
> Can we rename the caps_list argument to "caps" and remove the local
> variable of the same name?

Sure, will do.

Suzuki