[PATCH v2] powerpc: add documentation for HWCAPs

[Segher Boessenkool]

On Fri, Jul 15, 2022 at 03:41:20PM -0300, Tulio Magno Quites Machado Filho wrote:
> Nicholas Piggin <npiggin at gmail.com> writes:
> 
> > +PPC_FEATURE_ARCH_2_05
> > +    The processor supports the v2.05 userlevel architecture. Processors
> > +    supporting later architectures also set this feature.
> 
> I don't think this bit is enabled when processors support later architectures.
> In my tests, this behavior started only with v2.06, i.e. processors that
> support v2.07 enable bit v2.06, but do not enable bit v2.05.

That is a usability problem.  Can it be fixed, or will that create its
own compatibility problems?  In practice I mean.  If it is, the C
libraries could fix it up, for new programs, and then after a while the
kernel can do the sane thing?

How big is the problem, anyway?  Is it only 2.05, or also 2.04, 2.03?


Segher