irqchip: gicv3-its: Add limitation to page order

When required size of Device Table is out of the page allocator's
capability, the whole ITS will fail in probing. This actually is
not the hardware's problem and is mainly a limitation of the kernel
page allocator. This patch will keep ITS going on to the next
initializaion stage with an explicit warning.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Yun Wu <wuyun.wu@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1425659870-11832-10-git-send-email-marc.zyngier@arm.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 0fe25a97a5a9878d45f92b8ee346dfb56845ad31..ec20d4a942e05ac2dac1bca54ecabe687605c722 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -828,6 +828,11 @@ static int its_alloc_tables(struct its_node *its)
                        u32 ids = GITS_TYPER_DEVBITS(typer);
 
                        order = get_order((1UL << ids) * entry_size);
+                       if (order >= MAX_ORDER) {
+                               order = MAX_ORDER - 1;
+                               pr_warn("%s: Device Table too large, reduce its page order to %u\n",
+                                       its->msi_chip.of_node->full_name, order);
+                       }
                }
 
                alloc_size = (1 << order) * PAGE_SIZE;