irqchip/gic-v3-its: Don't bind LPI to unavailable NUMA node

BugLink: http://bugs.launchpad.net/bugs/1807469
commit c1797b11a09c8323c92b074fd48b89a936c991d0 upstream.

On a NUMA system, if an ITS is local to an offline node, the ITS driver may
pick an offline CPU to bind the LPI.  In this case, pick an online CPU (and
the first one will do).

But on some systems, binding an LPI to non-local node CPU may cause
deadlock (see Cavium erratum 23144).  In this case, just fail the activate
and return an error code.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180622095254.5906-5-marc.zyngier@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index d49bd1120bd9a63e6ffcd071a5d0925e898955e2..da73b8fea770427f3c4a80445a69bc1f489f2291 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -2314,7 +2314,14 @@ static int its_irq_domain_activate(struct irq_domain *domain,
                cpu_mask = cpumask_of_node(its_dev->its->numa_node);
 
        /* Bind the LPI to the first possible CPU */
-       cpu = cpumask_first(cpu_mask);
+       cpu = cpumask_first_and(cpu_mask, cpu_online_mask);
+       if (cpu >= nr_cpu_ids) {
+               if (its_dev->its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144)
+                       return;
+
+               cpu = cpumask_first(cpu_online_mask);
+       }
+
        its_dev->event_map.col_map[event] = cpu;
        irq_data_update_effective_affinity(d, cpumask_of(cpu));