gpu: nvgpu: sanitize gk20a_vm_alloc_share()

Add sanity check for big_page_size parameter to avoid invoking
gk20a_init_vm() with a bogus big page size, potentially hitting a
BUG_ON there. Also, reorganize the code a bit to avoid memory leak in
case of bogus big page size, and properly forward the return value
from gk20a_init_vm().

Change-Id: I4eeada75415d2e9539b5e8859099cce35cd86db3
Signed-off-by: Sami Kiminki <skiminki@nvidia.com>
Reviewed-on: http://git-master/r/594469
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 11 insertions, 12 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
index 1cdb2f8a..e4186c95 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
@@ -2341,10 +2341,19 @@ int gk20a_vm_alloc_share(struct gk20a_as_share *as_share, u32 big_page_size)
         struct vm_gk20a *vm;
         char name[32];
         int err;
-        u32 default_big_page_size;
 
         gk20a_dbg_fn("");
 
+        if (big_page_size == 0)
+                big_page_size =
+                        gk20a_get_platform(g->dev)->default_big_page_size;
+
+        if (!is_power_of_2(big_page_size))
+                return -EINVAL;
+
+        if (!(big_page_size & g->gpu_characteristics.available_big_page_sizes))
+                return -EINVAL;
+
         vm = kzalloc(sizeof(*vm), GFP_KERNEL);
         if (!vm)
                 return -ENOMEM;
@@ -2355,20 +2364,10 @@ int gk20a_vm_alloc_share(struct gk20a_as_share *as_share, u32 big_page_size)
 
         snprintf(name, sizeof(name), "gk20a_as_%d", as_share->id);
 
-        default_big_page_size =
-                gk20a_get_platform(g->dev)->default_big_page_size;
-
-        if (big_page_size == 0)
-                big_page_size = default_big_page_size;
-
-        if (big_page_size != default_big_page_size &&
-            !g->ops.mm.set_big_page_size)
-                return -EINVAL;
-
         err = gk20a_init_vm(mm, vm, big_page_size, big_page_size << 10,
                             mm->channel.size, true, name);
 
-        return 0;
+        return err;
 }
 
 int gk20a_vm_release_share(struct gk20a_as_share *as_share)