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authorThomas Gleixner <tglx@linutronix.de>2020-07-24 22:44:41 +0200
committerThomas Gleixner <tglx@linutronix.de>2020-07-27 16:20:40 +0200
commitf0c7baca180046824e07fc5f1326e83a8fd150c7 (patch)
treec0c90fdd493b07c736f04d5b8bfed90843e215e2 /kernel
parentec0160891e387f4771f953b888b1fe951398e5d9 (diff)
downloadlinux-f0c7baca180046824e07fc5f1326e83a8fd150c7.tar.bz2
genirq/affinity: Make affinity setting if activated opt-in
John reported that on a RK3288 system the perf per CPU interrupts are all affine to CPU0 and provided the analysis: "It looks like what happens is that because the interrupts are not per-CPU in the hardware, armpmu_request_irq() calls irq_force_affinity() while the interrupt is deactivated and then request_irq() with IRQF_PERCPU | IRQF_NOBALANCING. Now when irq_startup() runs with IRQ_STARTUP_NORMAL, it calls irq_setup_affinity() which returns early because IRQF_PERCPU and IRQF_NOBALANCING are set, leaving the interrupt on its original CPU." This was broken by the recent commit which blocked interrupt affinity setting in hardware before activation of the interrupt. While this works in general, it does not work for this particular case. As contrary to the initial analysis not all interrupt chip drivers implement an activate callback, the safe cure is to make the deferred interrupt affinity setting at activation time opt-in. Implement the necessary core logic and make the two irqchip implementations for which this is required opt-in. In hindsight this would have been the right thing to do, but ... Fixes: baedb87d1b53 ("genirq/affinity: Handle affinity setting on inactive interrupts correctly") Reported-by: John Keeping <john@metanate.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Marc Zyngier <maz@kernel.org> Acked-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/87blk4tzgm.fsf@nanos.tec.linutronix.de
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/manage.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 2a9fec53e159..48c38e09c673 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -320,12 +320,16 @@ static bool irq_set_affinity_deactivated(struct irq_data *data,
struct irq_desc *desc = irq_data_to_desc(data);
/*
+ * Handle irq chips which can handle affinity only in activated
+ * state correctly
+ *
* If the interrupt is not yet activated, just store the affinity
* mask and do not call the chip driver at all. On activation the
* driver has to make sure anyway that the interrupt is in a
* useable state so startup works.
*/
- if (!IS_ENABLED(CONFIG_IRQ_DOMAIN_HIERARCHY) || irqd_is_activated(data))
+ if (!IS_ENABLED(CONFIG_IRQ_DOMAIN_HIERARCHY) ||
+ irqd_is_activated(data) || !irqd_affinity_on_activate(data))
return false;
cpumask_copy(desc->irq_common_data.affinity, mask);