[PATCH 3/5] arm_pmu: acpi: check for mismatched PPIs

[Mark Rutland]

On Mon, Dec 11, 2017 at 05:37:07PM +0000, Will Deacon wrote:
> On Wed, Nov 01, 2017 at 02:12:37PM +0000, Mark Rutland wrote:
> > The arm_pmu platform code explicitly checks for mismatched PPIs at probe
> > time, while the ACPI code leaves this to the core code. Future
> > refactoring will make this difficult for the core code to check, so
> > let's have the ACPI code check this explicitly.
> > 
> > As before, upon a failure we'll continue on without an interrupt. Ho
> > hum.
> > 
> > Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> > Cc: Will Deacon <will.deacon at arm.com>
> > ---
> >  drivers/perf/arm_pmu.c      | 16 ++++------------
> >  drivers/perf/arm_pmu_acpi.c | 42 ++++++++++++++++++++++++++++++++++++++----
> >  2 files changed, 42 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
> > index 3d6d4c5f2356..e0242103d904 100644
> > --- a/drivers/perf/arm_pmu.c
> > +++ b/drivers/perf/arm_pmu.c
> > @@ -557,18 +557,10 @@ int armpmu_request_irq(struct arm_pmu *armpmu, int cpu)
> >  	if (!irq)
> >  		return 0;
> >  
> > -	if (irq_is_percpu_devid(irq) && cpumask_empty(&armpmu->active_irqs)) {
> > -		err = request_percpu_irq(irq, handler, "arm-pmu",
> > -					 &hw_events->percpu_pmu);
> > -	} else if (irq_is_percpu_devid(irq)) {
> > -		int other_cpu = cpumask_first(&armpmu->active_irqs);
> > -		int other_irq = per_cpu(hw_events->irq, other_cpu);
> > -
> > -		if (irq != other_irq) {
> > -			pr_warn("mismatched PPIs detected.\n");
> > -			err = -EINVAL;
> > -			goto err_out;
> > -		}
> > +	if (irq_is_percpu_devid(irq)) {
> > +		if (cpumask_empty(&armpmu->active_irqs))
> 
> Why not leave this as before, with a '&&' operator?

Because then we'd fall into the else case (for SPIs), were the
active_irqs mask empty.

Previously, that would have been caught by the irq_is_percpu_devid(irq)
case that got removed.

I can instead make this:

	if (irq_is_percpu_devid(irq) && cpumask_empty(&armpmu->active_irqs)) {
		err = request_percpu_irq(irq, handler, "arm-pmu",
					 &hw_events->percpu_pmu);
	} else if (irq_is_percpu_devid(irq)) {
		/* nothing to do */
	} else  { 
		< SPI case >
	}

... but that seemed more painful to read.

Mark.