drm/radeon: allow userptr write access under certain conditions

It needs to be anonymous memory (no file mappings)
and we are requried to install an MMU notifier.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 12 insertions, 7 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
index 2a6fbf101cf0..01b58941acd4 100644
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -285,19 +285,24 @@ int radeon_gem_userptr_ioctl(struct drm_device *dev, void *data,
         if (offset_in_page(args->addr | args->size))
                 return -EINVAL;
 
-        /* we only support read only mappings for now */
-        if (!(args->flags & RADEON_GEM_USERPTR_READONLY))
-                return -EACCES;
-
         /* reject unknown flag values */
         if (args->flags & ~(RADEON_GEM_USERPTR_READONLY |
             RADEON_GEM_USERPTR_ANONONLY | RADEON_GEM_USERPTR_VALIDATE |
             RADEON_GEM_USERPTR_REGISTER))
                 return -EINVAL;
 
-        /* readonly pages not tested on older hardware */
-        if (rdev->family < CHIP_R600)
-                return -EINVAL;
+        if (args->flags & RADEON_GEM_USERPTR_READONLY) {
+                /* readonly pages not tested on older hardware */
+                if (rdev->family < CHIP_R600)
+                        return -EINVAL;
+
+        } else if (!(args->flags & RADEON_GEM_USERPTR_ANONONLY) ||
+                   !(args->flags & RADEON_GEM_USERPTR_REGISTER)) {
+
+                /* if we want to write to it we must require anonymous
+                   memory and install a MMU notifier */
+                return -EACCES;
+        }
 
         down_read(&rdev->exclusive_lock);