Re: [PATCH 05/15] irq: add generic_handle_arch_irq()

Guo Ren
2021-10-24T01:53:35Z

On Fri, Oct 22, 2021 at 4:52 PM Mark Rutland <mark.rutland@arm.com> wrote:
>
> On Fri, Oct 22, 2021 at 10:33:53AM +0800, Guo Ren wrote:
> > On Fri, Oct 22, 2021 at 2:03 AM Mark Rutland <mark.rutland@arm.com> wrote:
> > >
> > > Several architectures select GENERIC_IRQ_MULTI_HANDLER and branch to
> > > handle_arch_irq() without performing any entry accounting.
> > >
> > > Add a generic wrapper to handle the commoon irqentry work when invoking
>
> Ah, I'd typo'd 'common' there; I'll go fix that...
>
> > > handle_arch_irq(). Where an architecture needs to perform some entry
> > > accounting itself, it will need to invoke handle_arch_irq() itself.
> > >
> > > In subsequent patches it will become the responsibilty of the entry code
> > > to set the irq regs when entering an IRQ (rather than deferring this to
> > > an irqchip handler), so generic_handle_arch_irq() is made to set the irq
> > > regs now. This can be redundant in some cases, but is never harmful as
> > > saving/restoring the old regs nests safely.
> > Shall we remove old_regs save/restore in handle_domain_irq? It's duplicated.
>
> We do, in patch 15 when handle_domain_irq() is removed entirely. :)
I miss that patch. Yes, in generic_handle_domain_nmi.

>
> Removing it immediately in this patch would require more ifdeffery and/or
> another copy of handle_domain_irq(), and since the duplication doesn't cause a
> functional problem, I think it's better to live with the temporary duplication
> for the next few patches than to try to optimize the intermediate steps at the
> cost of legibility.
Thx for explaining.

Reviewed-by: Guo Ren <guoren@kernel.org>

>
> Thanks,
> Mark.
>
> > > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> > > Cc: Marc Zyngier <maz@kernel.org>
> > > Cc: Thomas Gleixner <tglx@linutronix.de>
> > > ---
> > > kernel/irq/handle.c | 18 ++++++++++++++++++
> > > 1 file changed, 18 insertions(+)
> > >
> > > diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
> > > index 221d80c31e94..27182003b879 100644
> > > --- a/kernel/irq/handle.c
> > > +++ b/kernel/irq/handle.c
> > > @@ -14,6 +14,8 @@
> > > #include <linux/interrupt.h>
> > > #include <linux/kernel_stat.h>
> > >
> > > +#include <asm/irq_regs.h>
> > > +
> > > #include <trace/events/irq.h>
> > >
> > > #include "internals.h"
> > > @@ -226,4 +228,20 @@ int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
> > > handle_arch_irq = handle_irq;
> > > return 0;
> > > }
> > > +
> > > +/**
> > > + * generic_handle_arch_irq - root irq handler for architectures which do no
> > > + * entry accounting themselves
> > > + * @regs: Register file coming from the low-level handling code
> > > + */
> > > +asmlinkage void noinstr generic_handle_arch_irq(struct pt_regs *regs)
> > > +{
> > > + struct pt_regs *old_regs;
> > > +
> > > + irq_enter();
> > > + old_regs = set_irq_regs(regs);
> > > + handle_arch_irq(regs);
> > > + set_irq_regs(old_regs);
> > > + irq_exit();
> > > +}
> > > #endif
> > > --
> > > 2.11.0
> > >
> >
> >
> > --
> > Best Regards
> > Guo Ren
> >
> > ML: https://lore.kernel.org/linux-csky/

--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/