[PATCH v4 19/29] arm64: enable PKEY support for CPUs with S1POE

[Dave Martin]

On Tue, Jul 16, 2024 at 04:17:12PM +0530, Anshuman Khandual wrote:
> 
> 
> On 5/3/24 18:31, Joey Gouly wrote:
> > Now that PKEYs support has been implemented, enable it for CPUs that
> > support S1POE.
> > 
> > Signed-off-by: Joey Gouly <joey.gouly at arm.com>
> > Cc: Catalin Marinas <catalin.marinas at arm.com>
> > Cc: Will Deacon <will at kernel.org>
> > Acked-by: Catalin Marinas <catalin.marinas at arm.com>
> 
> Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>
> 
> > ---
> >  arch/arm64/include/asm/pkeys.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm64/include/asm/pkeys.h b/arch/arm64/include/asm/pkeys.h
> > index a284508a4d02..3ea928ec94c0 100644
> > --- a/arch/arm64/include/asm/pkeys.h
> > +++ b/arch/arm64/include/asm/pkeys.h
> > @@ -17,7 +17,7 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
> >  
> >  static inline bool arch_pkeys_enabled(void)
> >  {
> > -	return false;
> > +	return system_supports_poe();
> >  }
> >  
> >  static inline int vma_pkey(struct vm_area_struct *vma)
> 
> Small nit. Would it better to be consistently using system_supports_poe()
> helper rather than arch_pkeys_enabled() inside arch/arm64/ platform code
> like - during POE fault handling i.e inside fault_from_pkey().
> 

(FWIW, arch_pkeys_enabled() looks like the hook for the arch to tell
the pkeys generic code whether the arch support is there, so I guess
the proposed change looks sensible to me.

For the arch backend code that is agnostic to whether pkeys is actually
in use, system_supports_poe() seems to be the more appropriate check.)

Cheers
---Dave