Re: [RFC v5 34/38] procfs: display the protection-key number associated with a vma

[Ram Pai]

On Tue, Jul 11, 2017 at 11:13:56AM -0700, Dave Hansen wrote:
> On 07/05/2017 02:22 PM, Ram Pai wrote:
> > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
> > +void arch_show_smap(struct seq_file *m, struct vm_area_struct *vma)
> > +{
> > +	seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
> > +}
> > +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
> 
> This seems like kinda silly unnecessary duplication.  Could we just put
> this in the fs/proc/ code and #ifdef it on ARCH_HAS_PKEYS?

Well x86 predicates it based on availability of X86_FEATURE_OSPKE.

powerpc doesn't need that check or any similar check. So trying to
generalize the code does not save much IMHO.

maybe have a seperate inline function that does
seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
and is called from x86 and powerpc's arch_show_smap()?
At least will keep the string format captured in 
one single place.

thoughts?
RP