Re: [PATCH v1 05/10] powerpc/mm: Do early ioremaps from top to bottom on PPC64 too.

[Christophe Leroy]

Le 20/08/2019 Ã 02:20, Michael Ellerman a ÃcritÂ:
> Nicholas Piggin <npiggin@xxxxxxxxx> writes:
> > Christophe Leroy's on August 14, 2019 6:11 am:
> > > Until vmalloc system is up and running, ioremap basically
> > > allocates addresses at the border of the IOREMAP area.
> > >
> > > On PPC32, addresses are allocated down from the top of the area
> > > while on PPC64, addresses are allocated up from the base of the
> > > area.
> >   
> > This series looks pretty good to me, but I'm not sure about this patch.
> >
> > It seems like quite a small divergence in terms of code, and it looks
> > like the final result still has some ifdefs in these functions. Maybe
> > you could just keep existing behaviour for this cleanup series so it
> > does not risk triggering some obscure regression?
>
> Yeah that is also my feeling. Changing it *should* work, and I haven't
> found anything that breaks yet, but it's one of those things that's
> bound to break something for some obscure reason.
>
> Christophe do you think you can rework it to retain the different
> allocation directions at least for now?

Yes I have started addressing the comments I received, and I think for 
now I'll keep all the machinery aside from the merge. Not sure yet if 
I'll leave it in pgtables_32/64.c or if I'll add ioremap_32/64.c

Christophe