Re: powernv/opal-irqchip: Fix double endian conversion

[Alistair Popple <alistair@popple.id.au>]

On Tue, 8 Dec 2015 09:10:19 Michael Ellerman wrote:
> Subject should start "powerpc/", so probably "powerpc/opal-irqchip:", I can fix
> it up here.

Ok, thanks.

> On Mon, 2015-07-12 at 00:28:28 UTC, Alistair Popple wrote:
> > The OPAL event calls return a mask of events that are active in big
> > endian format. This is checked when unmasking the events in the
> > irqchip by comparison with a cached value. The cached value was stored
> > in big endian format but should've been converted to CPU endian
> > first. This bug leads to OPAL event delivery being delayed or dropped
> > on some systems.
> > 
> > The bug is fixed by calling opal_handle_events(...) instead of
> > duplicating code in opal_event_unmask(...).
> > 
> > Signed-off-by: Alistair Popple <alistair@popple.id.au>
> > Reported-by: Douglas L Lehr <dllehr@us.ibm.com>
> > Cc: stable@vger.kernel.org
> 
> Which commit does it fix? Looks like:
> 
> Fixes: 9f0fd0499d30 ("powerpc/powernv: Add a virtual irqchip for opal events")

Yep.

> > diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c
> > index 2c91ee7..a387d18 100644
> > --- a/arch/powerpc/platforms/powernv/opal-irqchip.c
> > +++ b/arch/powerpc/platforms/powernv/opal-irqchip.c
> > @@ -43,11 +43,34 @@ static unsigned int opal_irq_count;
> >  static unsigned int *opal_irqs;
> >  
> >  static void opal_handle_irq_work(struct irq_work *work);
> > -static __be64 last_outstanding_events;
> > +static u64 last_outstanding_events;
> >  static struct irq_work opal_event_irq_work = {
> >  	.func = opal_handle_irq_work,
> >  };
> >  
> > +void opal_handle_events(uint64_t events)
> > +{
> > +	int virq, hwirq = 0;
> > +	u64 mask = opal_event_irqchip.mask;
> > +
> > +	if (!in_irq() && (events & mask)) {
> > +		last_outstanding_events = events;
> > +		irq_work_queue(&opal_event_irq_work);
> > +		return;
> > +	}
> > +
> > +	while (events & mask) {
> > +		hwirq = fls64(events) - 1;
> > +		if (BIT_ULL(hwirq) & mask) {
> > +			virq = irq_find_mapping(opal_event_irqchip.domain,
> > +						hwirq);
> > +			if (virq)
> > +				generic_handle_irq(virq);
> > +		}
> > +		events &= ~BIT_ULL(hwirq);
> > +	}
> > +}
> 
> So this is 100% just a move of the code from down below right?

That is correct - it should be identical.

Thanks.

- Alistair

> > @@ -55,12 +78,12 @@ static void opal_event_mask(struct irq_data *d)
> >  
> >  static void opal_event_unmask(struct irq_data *d)
> >  {
> > +	__be64 events;
> > +
> >  	set_bit(d->hwirq, &opal_event_irqchip.mask);
> >  
> > -	opal_poll_events(&last_outstanding_events);
> > -	if (last_outstanding_events & opal_event_irqchip.mask)
> > -		/* Need to retrigger the interrupt */
> > -		irq_work_queue(&opal_event_irq_work);
> > +	opal_poll_events(&events);
> > +	opal_handle_events(be64_to_cpu(events));
> >  }
> >  
> >  static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
> > @@ -96,29 +119,6 @@ static int opal_event_map(struct irq_domain *d, unsigned int irq,
> >  	return 0;
> >  }
> >  
> > -void opal_handle_events(uint64_t events)
> > -{
> > -	int virq, hwirq = 0;
> > -	u64 mask = opal_event_irqchip.mask;
> > -
> > -	if (!in_irq() && (events & mask)) {
> > -		last_outstanding_events = events;
> > -		irq_work_queue(&opal_event_irq_work);
> > -		return;
> > -	}
> > -
> > -	while (events & mask) {
> > -		hwirq = fls64(events) - 1;
> > -		if (BIT_ULL(hwirq) & mask) {
> > -			virq = irq_find_mapping(opal_event_irqchip.domain,
> > -						hwirq);
> > -			if (virq)
> > -				generic_handle_irq(virq);
> > -		}
> > -		events &= ~BIT_ULL(hwirq);
> > -	}
> > -}
> > -
> >  static irqreturn_t opal_interrupt(int irq, void *data)
> >  {
> >  	__be64 events;
> > @@ -131,7 +131,7 @@ static irqreturn_t opal_interrupt(int irq, void *data)
> >  
> >  static void opal_handle_irq_work(struct irq_work *work)
> >  {
> > -	opal_handle_events(be64_to_cpu(last_outstanding_events));
> > +	opal_handle_events(last_outstanding_events);
> >  }
> >  
> >  static int opal_event_match(struct irq_domain *h, struct device_node *node,
> 
> 
> cheers