irqchip/gicv3-its: Add range check for number of allocated pages

The number of pages for the its table may exceed the maximum of 256.
Adding a range check and limitting the number to its maximum.

Based on a patch from Tirumalesh Chalamarla <tchalamarla@cavium.com>.

Signed-off-by: Tirumalesh Chalamarla <tchalamarla@cavium.com>
Signed-off-by: Robert Richter <rrichter@cavium.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1442869119-1814-2-git-send-email-rric@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ac7ae2b3cb83..d9052fdf98d7 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -822,6 +822,7 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
                 u64 entry_size = GITS_BASER_ENTRY_SIZE(val);
                 int order = get_order(psz);
                 int alloc_size;
+                int alloc_pages;
                 u64 tmp;
                 void *base;
 
@@ -856,6 +857,14 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
                 }
 
                 alloc_size = (1 << order) * PAGE_SIZE;
+                alloc_pages = (alloc_size / psz);
+                if (alloc_pages > GITS_BASER_PAGES_MAX) {
+                        alloc_pages = GITS_BASER_PAGES_MAX;
+                        order = get_order(GITS_BASER_PAGES_MAX * psz);
+                        pr_warn("%s: Device Table too large, reduce its page order to %u (%u pages)\n",
+                                node_name, order, alloc_pages);
+                }
+
                 base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
                 if (!base) {
                         err = -ENOMEM;
@@ -884,7 +893,7 @@ retry_baser:
                         break;
                 }
 
-                val |= (alloc_size / psz) - 1;
+                val |= alloc_pages - 1;
 
                 writeq_relaxed(val, its->base + GITS_BASER + i * 8);
                 tmp = readq_relaxed(its->base + GITS_BASER + i * 8);