On Mon, Aug 31, 2015 at 6:01 PM, Andy Lutomirski <l...@amacapital.net> wrote: > On Mon, Aug 31, 2015 at 2:47 PM, Brian Gerst <brge...@gmail.com> wrote: >> On Mon, Aug 31, 2015 at 5:00 PM, Andy Lutomirski <l...@amacapital.net> wrote: >>> Why not just a struct? Also, why is this all tangled up in gsbase >>> initialization? >> >> It has to do with the fact that the GCC stackprotector is hardcoded to >> look for the canary at %gs:40. Since we also use %gs for the percpu >> segment, we have to make sure that the canary is placed at the start >> of the percpu section. Overlaying it onto the bottom of the IRQ stack >> and was the most convenient way to do it, with a side benefit that >> overflowing the stack will trip the canary. > > Would a struct not make more sense, then?
Why would it? A union shows the overlay better. -- Brian Gerst -- 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/
