gpu: nvgpu: Fix overflow of alloc length

Fix an issue where large ( > 4GB) allocations were not being computed
correctly. The two fields, pages and page_size, were both 32 bits so
when multiplied they easily overflowed. Simple fix is to cast them to
64 bits before multiplying them.

Change-Id: I63fa54679e485de5c3a99684cbeb72c6cdc65504
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/747429
Reviewed-by: Sami Kiminki <skiminki@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/771148
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
index 1e0fd6af..0deadfd0 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
@@ -2816,7 +2816,9 @@ int gk20a_vm_alloc_space(struct gk20a_as_share *as_share,
                                                  (u64)args->pages *
                                                  (u64)args->page_size);
         else
-                vaddr_start = gk20a_balloc(vma, args->pages * args->page_size);
+                vaddr_start = gk20a_balloc(vma,
+                                           (u64)args->pages *
+                                           (u64)args->page_size);
 
         if (!vaddr_start) {
                 kfree(va_node);