1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 98144fde1df0..86e4684adeb1 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -228,7 +228,7 @@ static struct its_collection *its_build_mapd_cmd(struct its_cmd_block *cmd,
                                                  struct its_cmd_desc *desc)
 {
         unsigned long itt_addr;
-        u8 size = order_base_2(desc->its_mapd_cmd.dev->nr_ites);
+        u8 size = ilog2(desc->its_mapd_cmd.dev->nr_ites);
 
         itt_addr = virt_to_phys(desc->its_mapd_cmd.dev->itt);
         itt_addr = ALIGN(itt_addr, ITS_ITT_ALIGN);
@@ -1043,11 +1043,18 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
         void *itt;
         int lpi_base;
         int nr_lpis;
+        int nr_ites;
         int cpu;
         int sz;
 
         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
-        sz = nvecs * its->ite_size;
+        /*
+         * At least one bit of EventID is being used, hence a minimum
+         * of two entries. No, the architecture doesn't let you
+         * express an ITT with a single entry.
+         */
+        nr_ites = max(2, roundup_pow_of_two(nvecs));
+        sz = nr_ites * its->ite_size;
         sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
         itt = kmalloc(sz, GFP_KERNEL);
         lpi_map = its_lpi_alloc_chunks(nvecs, &lpi_base, &nr_lpis);
@@ -1061,7 +1068,7 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
 
         dev->its = its;
         dev->itt = itt;
-        dev->nr_ites = nvecs;
+        dev->nr_ites = nr_ites;
         dev->lpi_map = lpi_map;
         dev->lpi_base = lpi_base;
         dev->nr_lpis = nr_lpis;