On Sat, Aug 12, 2017 at 12:57:37PM +0100, Mark Rutland wrote: > On Wed, Aug 09, 2017 at 02:07:52PM -0600, Tycho Andersen wrote: > > From: Juerg Haefliger <juerg.haefliger@xxxxxxx> > > > > If the page is unmapped by XPFO, a data cache flush results in a fatal > > page fault. So don't flush in that case. > > Do you have an example callchain where that happens? We might need to shuffle > things around to cater for that case. > > > @@ -30,7 +31,9 @@ void sync_icache_aliases(void *kaddr, unsigned long len) > > unsigned long addr = (unsigned long)kaddr; > > > > if (icache_is_aliasing()) { > > - __clean_dcache_area_pou(kaddr, len); > > + /* Don't flush if the page is unmapped by XPFO */ > > + if (!xpfo_page_is_unmapped(virt_to_page(kaddr))) > > + __clean_dcache_area_pou(kaddr, len); > > __flush_icache_all(); > > } else { > > flush_icache_range(addr, addr + len); > > I don't think this patch is correct. If data cache maintenance is required in > the absence of XPFO, I don't see why it wouldn't be required in the presence of > XPFO. > > I'm not immediately sure why the non-aliasing case misses data cache > maintenance. I couldn't spot where that happens otherwise. >From another look, it seems that flush_icache_range() performs the D-cache maintenance internally, so it's just a slightly misleading name. However, __flush_icache_all() does not, and does need separate D-cache maintenance. Thanks, Mark. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>