Subject: Re: [PATCH 2/2] powerpc/e6500: TLB miss handler with hardware tablewalk support

From: Benjamin Herrenschmidt <[email-masked]>
Date: Sun, 09 Sep 2012 09:09:01 +1000

On Fri, 2012-06-15 at 11:05 +1000, Benjamin Herrenschmidt wrote:
> > -#define MMU_PAGE_COUNT       14
> > +#define MMU_PAGE_2M  6
> > +#define MMU_PAGE_4M  7
> > +#define MMU_PAGE_8M  8
> > +#define MMU_PAGE_16M 9
> > +#define MMU_PAGE_64M 10
> > +#define MMU_PAGE_256M        11
> > +#define MMU_PAGE_1G  12
> > +#define MMU_PAGE_16G 13
> > +#define MMU_PAGE_64G 14
> > +
> > +#define MMU_PAGE_COUNT       15 

BTW. We are getting close to 16 here which is the max since we encode
the size into a 4-bit field in the slice masks on server.

Any chance if/when you respin, to add a BUILD_BUG_ON somewhere to ensure
that we never accidentally break that limit ? (With a comment).

If we need to scavenge a size, we can always get rid of the AP one, it's
not actually useful (we'll have to find a different way to store the
encodings on server if we ever support multiple size per segment).

Cheers,
Ben.