[PATCH 4.14 088/157] irqchip/gic-v3-its: Dont bind LPI to unavailable NUMA node

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yang Yingliang <yangyingliang@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Cc: Sumit Garg <sumit.garg@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20180622095254.5906-5-marc.zyngier@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/irqchip/irq-gic-v3-its.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- 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(stru
 		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 -EINVAL;
+
+		cpu = cpumask_first(cpu_online_mask);
+	}
+
 	its_dev->event_map.col_map[event] = cpu;
 	irq_data_update_effective_affinity(d, cpumask_of(cpu));