Messages in this thread | | | Date | Thu, 15 Oct 2020 17:17:56 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 4/5] x86: wire up TIF_NOTIFY_SIGNAL |
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On 10/15, Thomas Gleixner wrote: > > On Thu, Oct 15 2020 at 16:34, Oleg Nesterov wrote: > > On 10/15, Thomas Gleixner wrote: > >> Instead of adding this to every architectures signal magic, we can > >> handle TIF_NOTIFY_SIGNAL in the core code: > >> > >> static void handle_singal_work(ti_work, regs) > >> { > >> if (ti_work & _TIF_NOTIFY_SIGNAL) > >> tracehook_notify_signal(); > >> > >> arch_do_signal(ti_work, regs); > >> } > >> > >> loop { > >> if (ti_work & (SIGPENDING | NOTIFY_SIGNAL)) > >> handle_signal_work(ti_work, regs); > >> } > > > > To me this looks like unnecessary complication. We need to change > > every architecture anyway, how can this helper help? > > You need to change ONE architecture because nobody else uses the common > entry loop right now.
so we need to change other arches to use the common entry loop.
> For those who move over they have to supply > arch_do_signal() anyway,
and this arch_do_signal() should be changed to check _TIF_SIGPENDING.
See also my replies to 3/5. I strongly disagree with CONFIG_GENERIC_ENTRY. But even if we require CONFIG_GENERIC_ENTRY, why do we want this helper?
We can just change exit_to_user_mode_loop() to do
if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) { if (ti_work & _TIF_NOTIFY_SIGNAL) tracehook_notify_signal(); arch_do_signal(ti_work, regs); }
but I'd prefer to handle SIGPENDING/NOTIFY_SIGNAL in one place.
Oleg.
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