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    SubjectRe: [GIT] Sparc
    On Wed, Sep 22, 2010 at 08:53:49PM +0100, Al Viro wrote:
    > On Wed, Sep 22, 2010 at 12:08:53PM -0700, Linus Torvalds wrote:
    > > On Wed, Sep 22, 2010 at 11:53 AM, Al Viro <> wrote:
    > > >
    > > > Um, no. ?You've *already* called get_signal_to_deliver(). ?There had been
    > > > no SIGSEGV in sight. ?You happily went on to set a sigframe for e.g.
    > > > SIGHUP, but ran out of stack. ?At that point you get force_sigsegv()
    > > > from handle_signal(). ?_NOW_ you have a pending SIGSEGV
    > >
    > > Ahh. Ok. Different case from the one I thought you were worried about.
    > > And yeah, I guess that one does require us to mess with the low-level
    > > asm code (although I do wonder if we could not make the whole
    > > do_notify_resume + reschedule code be generic C code - it's a lot of
    > > duplicated subtle asm as it is).
    > Worse than just that... Note that on sparc you need to deal with
    > fault_in_user_windows(), which can also trigger signals.

    Actually, I wonder why don't we do the following:
    1) check wsaved first, do fault_in_user_windows() if needed (and probably do
    Something Cruel(tm) if we fail copy_to_user() in there)
    2) in a loop check if we need to reschedule / if we need to handle signals
    3) don't bother with wsaved checks in setup_frame() variants at all -
    wsaved can't grow back at that point; we also can use flush_user_windows()
    instead of full synchronize_user_stack() in there.

    It's definitely a separate patch, but it looks like it might be worth
    doing... Comments?

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      Last update: 2010-09-22 22:45    [W:0.019 / U:11.992 seconds]
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