[PATCHv2 2/3] arm64: cpufeature: reorder cpus_have_{const,final}_cap()

[Will Deacon]

On Fri, Oct 30, 2020 at 08:18:48AM +0000, Will Deacon wrote:
> On Mon, Oct 26, 2020 at 01:49:30PM +0000, Mark Rutland wrote:
> > In a subsequent patch we'll modify cpus_have_const_cap() to call
> > cpus_have_final_cap(), and hence we need to define cpus_have_final_cap()
> > first.
> > 
> > To make subsequent changes easier to follow, this patch reorders the two
> > without making any other changes.
> > 
> > There should be no functional change as a result of this patch.
> 
> You say this...
> 
> > 
> > Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> > Cc: David Brazdil <dbrazdil at google.com>
> > Cc: Marc Zyngier <maz at kernel.org>
> > Cc: Will Deacon <will at kernel.org>
> > ---
> >  arch/arm64/include/asm/cpufeature.h | 16 ++++++++--------
> >  1 file changed, 8 insertions(+), 8 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
> > index f7e7144af174c..5d18c54507e6a 100644
> > --- a/arch/arm64/include/asm/cpufeature.h
> > +++ b/arch/arm64/include/asm/cpufeature.h
> > @@ -428,35 +428,35 @@ static __always_inline bool __cpus_have_const_cap(int num)
> >  }
> >  
> >  /*
> > - * Test for a capability, possibly with a runtime check.
> > + * Test for a capability without a runtime check.
> >   *
> > - * Before capabilities are finalized, this behaves as cpus_have_cap().
> > + * Before capabilities are finalized, this will BUG().
> >   * After capabilities are finalized, this is patched to avoid a runtime check.
> >   *
> >   * @num must be a compile-time constant.
> >   */
> > -static __always_inline bool cpus_have_const_cap(int num)
> > +static __always_inline bool cpus_have_final_cap(int num)
> >  {
> >  	if (system_capabilities_finalized())
> >  		return __cpus_have_const_cap(num);
> >  	else
> > -		return cpus_have_cap(num);
> > +		BUG();
> 
> ... but isn't the failure case of calling cpus_have_final_cap() early now
> different? What does BUG() do at EL2 w/ nVHE?

Ah no, sorry, I see you're just moving things around and the diff makes it
look confusing (that and I've been up since 5:30 for KVM Forum).

So on closer inspection:

Acked-by: Will Deacon <will at kernel.org>

Will