With the Linux 3.16 kernel is Intel graphics driver support for Userptr, allows user-space to wrap up malloc'ed memory and turn them into GEM buffer objects. Besides the Intel DDX support, there's now userptr support within Mesa's DRM library.

The Userptr feature of being able to turn a memory pointer from user-space into a buffer object for the DRM graphics drivers is useful for GPGPU/compute and other scenarios. With Linux 3.17, the Radeon driver also has Userptr support for feeding these memory objects from user-space to kernel-space.

Today hitting Mesa/DRM Git is the Intel support for Userptr objects within the DRM library. The nearly 200 lines of new code allows userptr objects to be created and used via libdrm_intel.