irqchip/gicv3-its: Avoid cache flush beyond ITS_BASERn memory size

Function its_alloc_tables() maintains two local variables, "order" and
and "alloc_size", to hold memory size that has been allocated to
ITS_BASEn. We don't always refresh the variable alloc_size whenever
value of the variable order changes, causing the following two
problems.

  - Cache flush operation with size more than required.
  - Information reported by pr_info is not correct.

Use a helper macro that converts page order to size in bytes instead of
variable "alloc_size" to fix both the problems.

Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ff2be77a51f6..43dfd15c1dd2 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -78,6 +78,9 @@ struct its_node {
 
 #define ITS_ITT_ALIGN           SZ_256
 
+/* Convert page order to size in bytes */
+#define PAGE_ORDER_TO_SIZE(o)   (PAGE_SIZE << (o))
+
 struct event_lpi_map {
         unsigned long           *lpi_map;
         u16                     *col_map;
@@ -841,7 +844,6 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
                 u64 type = GITS_BASER_TYPE(val);
                 u64 entry_size = GITS_BASER_ENTRY_SIZE(val);
                 int order = get_order(psz);
-                int alloc_size;
                 int alloc_pages;
                 u64 tmp;
                 void *base;
@@ -873,9 +875,8 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
                         }
                 }
 
-                alloc_size = (1 << order) * PAGE_SIZE;
 retry_alloc_baser:
-                alloc_pages = (alloc_size / psz);
+                alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);
                 if (alloc_pages > GITS_BASER_PAGES_MAX) {
                         alloc_pages = GITS_BASER_PAGES_MAX;
                         order = get_order(GITS_BASER_PAGES_MAX * psz);
@@ -928,7 +929,7 @@ retry_baser:
                         shr = tmp & GITS_BASER_SHAREABILITY_MASK;
                         if (!shr) {
                                 cache = GITS_BASER_nC;
-                                __flush_dcache_area(base, alloc_size);
+                                __flush_dcache_area(base, PAGE_ORDER_TO_SIZE(order));
                         }
                         goto retry_baser;
                 }
@@ -961,7 +962,7 @@ retry_baser:
                 }
 
                 pr_info("ITS: allocated %d %s @%lx (psz %dK, shr %d)\n",
-                        (int)(alloc_size / entry_size),
+                        (int)(PAGE_ORDER_TO_SIZE(order) / entry_size),
                         its_base_type_string[type],
                         (unsigned long)virt_to_phys(base),
                         psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);