Re: [PATCH] MIPS: tlb-r4k: panic if the MMU doesn't support PAGE_SIZE

From: Ralf Baechle
Date: Fri Feb 12 2016 - 05:57:51 EST


On Thu, Feb 11, 2016 at 07:37:12PM +0000, Maciej W. Rozycki wrote:

> > > index 08318ec..4330315 100644
> > > --- a/arch/mips/mm/tlb-r4k.c
> > > +++ b/arch/mips/mm/tlb-r4k.c
> > > @@ -486,6 +487,10 @@ static void r4k_tlb_configure(void)
> > > * be set to fixed-size pages.
> > > */
> > > write_c0_pagemask(PM_DEFAULT_MASK);
> > > + back_to_back_c0_hazard();
> > > + if (read_c0_pagemask() != PM_DEFAULT_MASK)
> > > + panic("MMU doesn't support PAGE_SIZE=0x%lx", PAGE_SIZE);
>
> I think it would make sense to report here what the minimum/maximum page
> size actually supported is, so that the users know what there might be
> after.

This is a very unlikely error condition to be hit so I'd rather keep it
simple. Even just BUG_ON() would suffice.

Ralf