Re: [PATCH 1/3] arm64: spin-table: handle unmapped cpu-release-addrs

[Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>]

On Tue, Jul 29, 2014 at 04:20:46PM +0100, Arnd Bergmann wrote:
> On Tuesday 29 July 2014 11:15:45 Mark Salter wrote:
> > > -
> > > -     __flush_dcache_area(release_addr, sizeof(release_addr[0]));
> > > +     writeq_relaxed(__pa(secondary_holding_pen), release_addr);
> > > +     __flush_dcache_area(release_addr, sizeof(*release_addr));
> > 
> >        __flush_dcache_area((__force void *)release_addr, ... 
> > 
> > to avoid sparse warning.

Presumably we'd get this for the write_relaxed too?

> > 
> 
> I think it would be cleaner to drop the __iomem annotation and use vmap()
> rather than ioremap(). That requires having a 'struct page' though, which
> I'm not sure you have.

As far as I am aware, we'd only have a struct page for memory falling in
the linear map, so for the cases this patch is actually required we
wouldn't have a struct page.

So it looks like I should just make release_addr a void __iomem *. Then
this line can just be:

__flush_dcache_area(release_addr, 8);

Where we could replace 8 with sizeof(u64), sizeof(__le64), etc if 8 is
too magic.

How does that sound?

Thanks,
Mark.