irqchip/gic-v3-its: Add missing cache flushes

commit 5a9a8915 upstream.

When the ITS is configured for non-cacheable transactions, make sure
that the allocated, zeroed memory is flushed to the Point of
Coherency, allowing the ITS to observe the zeros instead of random
garbage (or even get its own data overwritten by zeros being evicted
from the cache...).

Fixes: 241a386c "irqchip: gicv3-its: Use non-cacheable accesses when no shareability"
Reported-and-tested-by: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Pavel Fedin <p.fedin@samsung.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1442142873-20213-3-git-send-email-marc.zyngier@arm.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/irqchip/irq-gic-v3-its.c

@@ -921,8 +921,10 @@ static int its_alloc_tables(struct its_node *its)
 			 * non-cacheable as well.
 			 */
 			shr = tmp & GITS_BASER_SHAREABILITY_MASK;
-			if (!shr)
+			if (!shr) {
 				cache = GITS_BASER_nC;
+				__flush_dcache_area(base, alloc_size);
+			}
 			goto retry_baser;
 		}
 
@@ -1163,6 +1165,8 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
 		return NULL;
 	}
 
+	__flush_dcache_area(itt, sz);
+
 	dev->its = its;
 	dev->itt = itt;
 	dev->nr_ites = nr_ites;