[Linaro-mm-sig] Re: [PATCH v2 7/7] accel/rocket: Add IOCTLs for synchronizing memory accesses

On 2/25/2025 12:55 AM, Tomeu Vizoso wrote:

+int rocket_ioctl_fini_bo(struct drm_device *dev, void *data, struct drm_file *file) +{

• struct drm_rocket_fini_bo *args = data;
• struct drm_gem_object *gem_obj;
• struct rocket_gem_object *rkt_obj;
• struct drm_gem_shmem_object *shmem_obj;
• struct rocket_device *rdev = to_rocket_device(dev);
• gem_obj = drm_gem_object_lookup(file, args->handle);
• if (!gem_obj)

• return -ENOENT;
  

• rkt_obj = to_rocket_bo(gem_obj);
• shmem_obj = &rkt_obj->base;
• WARN_ON(rkt_obj->last_cpu_prep_op == 0);
• for (unsigned int core = 1; core < rdev->num_cores; core++) {

• dma_sync_sgtable_for_device(rdev->cores[core].dev, shmem_obj->sgt,
  

• 			    rocket_op_to_dma_dir(rkt_obj->last_cpu_prep_op));
  

• }
• rkt_obj->last_cpu_prep_op = 0;
• drm_gem_object_put(gem_obj);
• return 0;

+}

flags must be 0, and you must check that here. You do not appear to be doing that. Otherwise, userspace may put a value in flags, which is ignored now, but later when you define flags for a purpose, existing userspace will be broken - a uapi violation.