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

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: 241a386c7dbb "irqchip: gicv3-its: Use non-cacheable accesses when no shareability"
Reported-and-tested-by: Stuart Yoder <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Cc: [email protected]
Cc: Pavel Fedin <[email protected]>
Cc: Jason Cooper <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 26b55c53755f..ac7ae2b3cb83 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -898,8 +898,10 @@ retry_baser:
 			 * 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;
 		}
 
@@ -1140,6 +1142,8 @@ 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;