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authorThomas Gleixner <tglx@linutronix.de>2014-04-16 14:36:44 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-07 13:25:29 -0700
commit73ce7ddb70a0c7603b37d375db4b99e2884bd666 (patch)
tree3e3ac5ce3689a4776cb774bf1e884aa90e199fea /kernel
parent2e020bb03a2db393dc7def211a5e62440db7d0b8 (diff)
genirq: Allow forcing cpu affinity of interrupts
commit 01f8fa4f01d8362358eb90e412bd7ae18a3ec1ad upstream. The current implementation of irq_set_affinity() refuses rightfully to route an interrupt to an offline cpu. But there is a special case, where this is actually desired. Some of the ARM SoCs have per cpu timers which require setting the affinity during cpu startup where the cpu is not yet in the online mask. If we can't do that, then the local timer interrupt for the about to become online cpu is routed to some random online cpu. The developers of the affected machines tried to work around that issue, but that results in a massive mess in that timer code. We have a yet unused argument in the set_affinity callbacks of the irq chips, which I added back then for a similar reason. It was never required so it got not used. But I'm happy that I never removed it. That allows us to implement a sane handling of the above scenario. So the affected SoC drivers can add the required force handling to their interrupt chip, switch the timer code to irq_force_affinity() and things just work. This does not affect any existing user of irq_set_affinity(). Tagged for stable to allow a simple fix of the affected SoC clock event drivers. Reported-and-tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Tomasz Figa <t.figa@samsung.com>, Cc: Daniel Lezcano <daniel.lezcano@linaro.org>, Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: linux-arm-kernel@lists.infradead.org, Link: http://lkml.kernel.org/r/20140416143315.717251504@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/manage.c17
1 files changed, 6 insertions, 11 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 9bd5c8a6c8ee..8815abfdf2cb 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -150,7 +150,7 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
struct irq_chip *chip = irq_data_get_irq_chip(data);
int ret;
- ret = chip->irq_set_affinity(data, mask, false);
+ ret = chip->irq_set_affinity(data, mask, force);
switch (ret) {
case IRQ_SET_MASK_OK:
cpumask_copy(data->affinity, mask);
@@ -162,7 +162,8 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
return ret;
}
-int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
+int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
+ bool force)
{
struct irq_chip *chip = irq_data_get_irq_chip(data);
struct irq_desc *desc = irq_data_to_desc(data);
@@ -172,7 +173,7 @@ int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
return -EINVAL;
if (irq_can_move_pcntxt(data)) {
- ret = irq_do_set_affinity(data, mask, false);
+ ret = irq_do_set_affinity(data, mask, force);
} else {
irqd_set_move_pending(data);
irq_copy_pending(desc, mask);
@@ -187,13 +188,7 @@ int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
return ret;
}
-/**
- * irq_set_affinity - Set the irq affinity of a given irq
- * @irq: Interrupt to set affinity
- * @mask: cpumask
- *
- */
-int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
+int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
{
struct irq_desc *desc = irq_to_desc(irq);
unsigned long flags;
@@ -203,7 +198,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
return -EINVAL;
raw_spin_lock_irqsave(&desc->lock, flags);
- ret = __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
+ ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
raw_spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}