On Sat, Apr 28, 2012 at 12:15:26AM +0100, Al Viro wrote:
> I think all such architectures need that check lifted to do_notify_resume()
> (and the rest needs it killed, of course). Including x86, by the look
> of it - we _probably_ can't get there with TIF_NOTIFY_RESUME and
> !user_mode(regs), but I'm not entirely sure of that. arm is in about the
> same situation; alpha, ppc{32,64}, sparc{32,64} and m68k really can't get
> there like that (they all check it in the asm glue). mips probably might,
> unless I'm misreading their ret_from_fork()... Fun.
Speaking of user_mode() oddities - may I politely inquire what had
been smoked to inspire this (in arch/s390/kernel/signal.c):
/* This is the legacy signal stack switching. */
else if (!user_mode(regs) &&
!(ka->sa.sa_flags & SA_RESTORER) &&
ka->sa.sa_restorer) {
sp = (unsigned long) ka->sa.sa_restorer;
}
especially when all paths leading to that come through do_signal() that does
if (!user_mode(regs))
return;
on the same regs. It had been like that since 2.3.99pre8 when s390 went
into the tree... It looks vaguely similar to i386
/* This is the legacy signal stack switching. */
if ((regs->ss & 0xffff) != __USER_DS &&
!(ka->sa.sa_flags & SA_RESTORER) &&
ka->sa.sa_restorer)
sp = (unsigned long) ka->sa.sa_restorer;
but there the code is at least not unreachable...
--
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
