[PATCH] ARM: gic: fix irq affinity mismatch.

[PATCH] ARM: gic: fix irq affinity mismatch.

[Chanho Min]

Even if we set affinity to multiple cpus via procfs, gic_set_affinity
allows to set one target only. But, '/proc/irq/xxx/smp_affinity' shows
as we are successful in the setting of multiple affinity. Thus irq_data->
affinity mismatches with the GICD_ITARGETSRs.

fix it as bellows.
- Set the default affinity to the boot cpu in gic_dist_init. thereafter,
irq_data->affinity will be set to default 1-bit affinity.
- Even if we write multiple bits to smp_affinity, both irq_data and gic
register will be set one cpu. procfs will show 1 bit affinity as well.

Signed-off-by: Chanho Min <chanho.min@lge.com>
---
 arch/arm/common/gic.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index aa52699..fb8ac8e 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -249,6 +249,12 @@ static int gic_set_affinity(struct irq_data *d,
const struct cpumask *mask_val,
 	writel_relaxed(val | bit, reg);
 	raw_spin_unlock(&irq_controller_lock);

+	if (cpumask_next_and(cpu, mask_val, cpu_present_mask) < nr_cpu_ids) {
+		cpumask_clear(d->affinity);
+		cpumask_set_cpu(cpu, d->affinity);
+		return IRQ_SET_MASK_OK_NOCOPY;
+	}
+
 	return IRQ_SET_MASK_OK;
 }
 #endif
@@ -355,6 +361,12 @@ static void __init gic_dist_init(struct gic_chip_data *gic)
 	cpumask |= cpumask << 8;
 	cpumask |= cpumask << 16;

+#ifdef CONFIG_SMP
+	/* Set the default affinity to the boot cpu. */
+	cpumask_clear(irq_default_affinity);
+	cpumask_set_cpu(cpu, irq_default_affinity);
+#endif
+
 	writel_relaxed(0, base + GIC_DIST_CTRL);

 	/*
-- 
1.7.9.5

Re: [PATCH] ARM: gic: fix irq affinity mismatch.

[Russell King - ARM Linux]

On Mon, Sep 24, 2012 at 12:06:19PM +0900, Chanho Min wrote:
> Even if we set affinity to multiple cpus via procfs, gic_set_affinity
> allows to set one target only. But, '/proc/irq/xxx/smp_affinity' shows
> as we are successful in the setting of multiple affinity. Thus irq_data->
> affinity mismatches with the GICD_ITARGETSRs.
> 
> fix it as bellows.
> - Set the default affinity to the boot cpu in gic_dist_init. thereafter,
> irq_data->affinity will be set to default 1-bit affinity.
> - Even if we write multiple bits to smp_affinity, both irq_data and gic
> register will be set one cpu. procfs will show 1 bit affinity as well.

This has come up before.  There is no requirement to make the affinity
mask reflect back to userspace what the hardware is doing.  So, NAK.