On Sun, Jul 14, 2013 at 12:23 PM, Jeremy Fitzhardinge <jer...@goop.org> wrote: > > It looks like that if the base address isn't aligned then neither is the > generated access, so you could get a protection fault if it overlaps a > page boundary, which is a semantic rather than purely operational > difference.
You could also get AC fault for the btq if the thing is only long-aligned. But yes, I checked the Intel manuals too, and the access size is actually not well-specified (even the 16-bit case says "may", I think), so both the page-fault and the alignment fault are purely theoretical. And i'm too lazy to bother trying the (easily testable) alignment fault case in practice, since (a) nobody cares and (b) nobody cares. In the (unlikely) situation that somebody actually cares, that somebody should obviously then have to specify "btl" vs "btq". Assuming the hardware cares, which is testable but might be micro-architecture dependent. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/