gpu: nvgpu: Fix possible overflow in buddy allocator

Fix a possible overflow in the buddy allocator's initialization code. In
practice it should never happen that pde size is greater than 32bits but
this makes coverity happy.

Coverity ID 54964

Change-Id: I886fd962bb3e9e328f7305bdcf69827979a39a21
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1210316
GVS: Gerrit_Virtual_Submit
Reviewed-by: Sachit Kadle <skadle@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_allocator_buddy.c b/drivers/gpu/nvgpu/gk20a/gk20a_allocator_buddy.c
index 8cd1bd0b..dd7f4d27 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_allocator_buddy.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_allocator_buddy.c
@@ -1101,6 +1101,7 @@ int __gk20a_buddy_allocator_init(struct gk20a_allocator *__a,
                                  u64 max_order, u64 flags)
 {
         int err;
+        u64 pde_size;
         struct gk20a_buddy_allocator *a;
 
         /* blk_size must be greater than 0 and a power of 2. */
@@ -1140,8 +1141,10 @@ int __gk20a_buddy_allocator_init(struct gk20a_allocator *__a,
         }
 
         a->vm = vm;
-        if (flags & GPU_ALLOC_GVA_SPACE)
-                a->pte_blk_order = balloc_get_order(a, vm->big_page_size << 10);
+        if (flags & GPU_ALLOC_GVA_SPACE) {
+                pde_size = ((u64)vm->big_page_size) << 10;
+                a->pte_blk_order = balloc_get_order(a, pde_size);
+        }
 
         /*
          * When we have a GVA space with big_pages enabled the size and base