Re: [PATCH v2 07/20] arm64: capabilities: Filter the entries based on a given mask

[Suzuki K Poulose]

On 07/02/18 10:38, Dave Martin wrote:
> On Wed, Jan 31, 2018 at 06:27:54PM +0000, Suzuki K Poulose wrote:
> > While processing the list of capabilities, it is useful to
> > filter out some of the entries based on the given mask for the
> > scope of the capabilities to allow better control. This can be
> > used later for handling LOCAL vs SYSTEM wide capabilities and more.
> > All capabilities should have their scope set to either LOCAL_CPU or
> > SYSTEM. No functional/flow change.
> >
> > 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>
> > ---
> >   arch/arm64/include/asm/cpufeature.h |  2 ++
> >   arch/arm64/kernel/cpufeature.c      | 35 ++++++++++++++++++++++++-----------
> >   2 files changed, 26 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
> > index 69b5ce366598..cda62b70d338 100644
> > --- a/arch/arm64/include/asm/cpufeature.h
> > +++ b/arch/arm64/include/asm/cpufeature.h
> > @@ -198,6 +198,8 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
> >   /* Is it safe for a late CPU to miss this capability when system has it */
> >   #define ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU	((u16)BIT(5))
> >   
> > +#define ARM64_CPUCAP_SCOPE_ALL			 \
> > +	(ARM64_CPUCAP_SCOPE_LOCAL_CPU | ARM64_CPUCAP_SCOPE_SYSTEM)
>
> Perhaps we could just use _MASK rather than having a separate #define,
> but it's good either way.
>
> Is there a situation in which _ALL and _MASK would need to be
> different?

No, it just makes it easier to read the code. I have switched to:

> > -static bool __verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_list)
> > +static bool __verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_list,
> > +				    u16 scope_mask)
> >   {
> >   	bool cpu_has_cap, system_has_cap;
> >   	const struct arm64_cpu_capabilities *caps = caps_list;
> >   
> > +	scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
> >   	for (; caps->matches; caps++) {
> > +
>
> Nit: extra blank line?

Fixed.

> [...]
>
> With that fixed,
>
> Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>

Thanks
Suzuki