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

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>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 13f195c..2ea39a8 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -2221,7 +2221,14 @@ static void 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_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));
 
        its_dev->event_map.col_map[event] = cpu;
        irq_data_update_effective_affinity(d, cpumask_of(cpu));