In a posting at Geeks3D.com, Intel's Windows team has updated their OpenGL driver while silently now having OpenGL 4.0 compliance. This Intel OpenGL 4.0 support does include tessellation support.
So while the Intel Windows driver has achieved OpenGL 4.0 with OpenCL 1.1, the Intel Linux driver is still at OpenGL 3.0 without OpenCL. Well, technically it's only OpenGL 2.1 complete if not having a xorg-server built with the GLX_ARB_create_context patches (currently only in X.Org Server Git master) and building Mesa with the patent encumbered texture-float support. OpenGL 3.1 on the Intel Linux driver isn't likely until next year and OpenGL 4.0 on the Intel Mesa driver probably won't be there for another two years or so.
Even after Intel Haswell ships next year, that support too will be stuck to the GL3 limitations. When Intel Broadwell is here in 2014, hopefully then we will see OpenGL 4.x support for Intel Linux at launch, but chances are by then there will be OpenGL 5.0. I'd certainly like to see the GL support catch-up quicker for the open-source drivers under Linux, but at this point it's not happening without a fundamental change at Intel.
Then in terms of Intel OpenCL on Linux, they do have their closed-source OpenCL SDK for Linux, but that only runs on the CPU side and not with the GPU for Ivy Bridge. The Intel OTC developers may be looking at OpenCL support, but so far no code for their Linux graphics driver to allow this has appeared.
With the new Windows HD Graphics v2729 driver, it would be interesting to see if the performance has changed at all. Benchmarks I published just a few days ago comparing the Windows 7 vs. Ubuntu Linux Intel GL performance for both Sandy Bridge and Ivy Bridge showed the Windows OpenGL driver these days having the performance advantage. Additional Intel Ivy Bridge Linux benchmarks are still set to be published in the coming days.