On Mon, 2008-12-08 at 19:14 -0800, Trent Piepho wrote: > On Tue, 2 Dec 2008, Kumar Gala wrote: > > Added 85xx specifc smp_ops structure. We use ePAPR style boot release > > and the MPIC for IPIs at this point. > > > > Additionally added routines for secondary cpu entry and initializtion. > > > > @@ -740,6 +750,9 @@ finish_tlb_load: > > #else > > rlwimi r12, r11, 26, 27, 31 /* extract WIMGE from pte */ > > #endif > > +#ifdef CONFIG_SMP > > + ori r12, r12, MAS2_M > > +#endif > > mtspr SPRN_MAS2, r12 > > Wouldn't it be more efficient to set _PAGE_COHERENT when the pte is created > vs setting MAS2_M each time it's loaded? > > Is it correct to set MAS2_M for all pages, even uncached ones?
That sounds strange indeed. However, I would do it the other way around, which is to set M in the PTEs and filter it out on !SMP. The stuff in pgtable is a bit of a mess at the moment, which makes things harder though. I have some patches reworking bits for 64-bit but I haven't had a chance to sort that out yet for 32-bit. > The code for ioremap() has this: > > /* Non-cacheable page cannot be coherent */ > if (flags & _PAGE_NO_CACHE) > flags &= ~_PAGE_COHERENT; > > It seems odd that ioremap would explictly unset _PAGE_COHERENT when the > code that sets the tlb will just force it back on. Depends on your HW implementation but yes, it's fishy to have M and I set at the same time. Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev