On Tue, 19 May 2020 23:25:43 +0100 Valentin Schneider <[email protected]> wrote:
> On 19/05/20 17:17, Marc Zyngier wrote: > > For irqchips using the fasteoi flow, IPIs are a bit special. > > > > They need to be EOId early (before calling the handler), as > > funny things may happen in the handler (they do not necessarily > > behave like a normal interrupt), and that the arch code is > > already handling the stats. > > > > Signed-off-by: Marc Zyngier <[email protected]> > > --- > > include/linux/irq.h | 1 + > > kernel/irq/chip.c | 26 ++++++++++++++++++++++++++ > > 2 files changed, 27 insertions(+) > > > > diff --git a/include/linux/irq.h b/include/linux/irq.h > > index 8d5bc2c237d7..726f94d8b8cc 100644 > > --- a/include/linux/irq.h > > +++ b/include/linux/irq.h > > @@ -621,6 +621,7 @@ static inline int irq_set_parent(int irq, int > > parent_irq) > > */ > > extern void handle_level_irq(struct irq_desc *desc); > > extern void handle_fasteoi_irq(struct irq_desc *desc); > > +extern void handle_percpu_devid_fasteoi_ipi(struct irq_desc *desc); > > extern void handle_edge_irq(struct irq_desc *desc); > > extern void handle_edge_eoi_irq(struct irq_desc *desc); > > extern void handle_simple_irq(struct irq_desc *desc); > > diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c > > index 41e7e37a0928..7b0b789cfed4 100644 > > --- a/kernel/irq/chip.c > > +++ b/kernel/irq/chip.c > > @@ -955,6 +955,32 @@ void handle_percpu_devid_irq(struct irq_desc *desc) > > chip->irq_eoi(&desc->irq_data); > > } > > > > +/** > > + * handle_percpu_devid_fasteoi_ipi - Per CPU local IPI handler with per cpu > > + * dev ids > > + * @desc: the interrupt description structure for this irq > > + * > > + * The biggest differences with the IRQ version are that: > > + * - the interrupt is EOIed early, as the IPI could result in a context > > + * switch, and we need to make sure the IPI can fire again > > + * - Stats are usually handled at the architecture level, so we ignore them > > + * here > > + */ > > +void handle_percpu_devid_fasteoi_ipi(struct irq_desc *desc) > > +{ > > + struct irq_chip *chip = irq_desc_get_chip(desc); > > + struct irqaction *action = desc->action; > > + unsigned int irq = irq_desc_get_irq(desc); > > + irqreturn_t res; > > + > > Tied to the following patch, does that want something like > > + if (!irq_settings_is_no_accounting(desc)) > + __kstat_incr_irqs_this_cpu(desc); > + > > While I'm at it, now that we would have IPIs as 'normal' interrupts, what > prevents us from getting rid of the arch-side accounting? Is it just that > we are keeping it as long as handle_IPI() lives, or are there more hurdles > hidden around? See my reply to Florian. I need to mop the rest of the 32bit irqchips without having the HW (hip04 is almost a copy of the GIC driver, and the Marvell horror is very RPi like). Once this is done, we can kill the home-brewed stuff and rely on core infrastructure. Thanks, M. -- Jazz is not dead. It just smells funny...
