Re: [RFC][PATCH 34/35] powerpc use generic ptemap.h

[Dave Hansen <dave@linux.vnet.ibm.com>]

On Fri, 2009-05-01 at 13:46 -0400, Christoph Hellwig wrote:
> On Fri, May 01, 2009 at 07:42:54AM -0700, Dave Hansen wrote:
 
> > powerpc is a bid of an oddball here.  It seems to have CONFIG_HIGHPTE
> > behavior at all times when compiled as 32-bit.  There's even an
> > #ifdef CONFIG_HIGHPTE in arch/powerpc/mm/pgtable_32.c, but there's no
> > trace of HIGHPTE in Kconfig anywhere.
> > 
> > This gives ppc32 an explicit HIGHPTE in Kconfig so that we can use
> > the #ifdef in asm-generic/ptemap.h and let ppc use the generic code
> > with x86 and frv.
> 
> But if you enabled HIGHPTE you need to remove that ifdef in pgtable_32.c
> because it didn't get triggered before.

OK, that makes sense.

> >  #define _POWERPC_ASM_PTEMAP_H
> >  
> >  #ifndef __powerpc64__
> > +/*
> > + * This lets us use the x86 implementation
> > + * in the generic ptemap.h
> > + */
> > +#define kmap_atomic_pte(page, type) kmap_atomic(page, type)
> > +#endif
> 
> That comment doesn't make any sense to me, x86 should have nothing to do
> with it.  Also the comment would comfortably fit into a single line
> instead of two.

You're right, that is more of a changelog thing.  I'll fix it up.

-- Dave