On Fri, Aug 23, 2019 at 7:56 AM Robin Murphy <robin.murphy@xxxxxxx> wrote: > > On 23/08/2019 03:12, Rob Herring wrote: > > tlb_inv_context() hook is only called when freeing the page tables. There's > > no point in flushing only to free the page tables immediately following. > > FWIW, in general the point of flushing is *because* we're about to free > the pagetables - if there's any possibility that the hardware could > continue to issue translation table walks (speculative or otherwise) > after those pages have been reused by someone else, TLB badness may ensue. > > For panfrost in particular I suspect we can probably get away without > it, at least for the moment, but it might be worth moving the flush to > mmu_disable() for complete peace of mind (which kind of preempts the > sort of thing that per-process AS switching will want anyway). There's bigger problem that mmu_disable() is still only called for AS0 and only for driver unload. I guess we should fix that and then figure out where a flush is needed if at all. I would think changing the TTBR would be enough to quiesce the h/w and TLBs. That seems to be the case in my testing of switching address spaces. Rob _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
