>>> On 28.04.11 at 14:53, Heiko Carstens <heiko.carstens@xxxxxxxxxx> wrote: > On Thu, Apr 28, 2011 at 01:07:07PM +0100, Jan Beulich wrote: >> >>> On 28.04.11 at 13:47, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: >> > On Thu, Apr 28, 2011 at 13:40, Jan Beulich <JBeulich@xxxxxxxxxx> wrote: >> >>>>> On 28.04.11 at 12:43, Heiko Carstens <heiko.carstens@xxxxxxxxxx> wrote: >> >>> On Wed, Apr 27, 2011 at 04:36:04PM +0100, Jan Beulich wrote: >> >>> That's odd. The kernel actually writes to it (sort_main_extable()), so >> >>> it shouldn't be in the ro data section, but the data section. >> >> >> >> This area does get written, but only at boot time, before read-only >> >> data gets set to r/o (on x86 at least). With this in mind, it's better >> >> to place it in .rodata, as that way run-time protection will be in place >> >> (and I think you agree that it was misplaced in .text in any case). >> > >> > Which means it may be in ROM (which is really read-only) on some embedded >> > devices, so it cannot be sorted? >> >> Perhaps - but since sorting is a requirement, people building such >> systems must have found a way... Anyway, I don't see where both > > Yes, we found a way on s390: we put the exception table in the data section. > >> your and Heiko's comment are heading, since the situation is even >> worse without the patch afaics (since .text gets marked read-only >> as much as .rodata does, and could equally be placed in ROM). > > My point is that your default is wrong. If it makes sense to put the extable > into the rodata section then an architecture could do so. However making the > default to put data into the rodata section that is actually written to is > the wrong approach. > It just asks for breakage. The patch doesn't make this the default - it just makes it possible for an architecture to do so. Jan -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
