Hi Jookia,
I see. How does proprietary userspace code work then?
please see my reply to Vasily.
Many projects have used the idea of glue code as a way to link proprietary and free software together as a way 'around' the GPL, and this sounds a bit like the same thing. It's questionable if it works though.
I wonder, is this a vague gut feeling or a well-informed concern? If the former, I would very much appreciate you to not spread uncertainty. It is definitely not my intention to work around the GPL!
Genode's license is delicate because Genode plays a number of roles. One particularly important role for this discussion is its role of a "system library". As stated in the GPL FAQ, the GPL acknowledges that system libraries may be proprietary [1]. Even if Genode was solely proprietary, its role of a "system library" would allow the combination of GPL code with it (at least the portions of Genode that correspond to the functionality of a system library).
[1] https://www.gnu.org/licenses/gpl-faq.html#SystemLibraryException
If proprietary software is accepted to have this role but GPL software would not because of the GPLv2/v3 incompatibility, this would be a gross contradiction with the spirit of Free Software. Furthermore, with the linking exception clause, we make our stance unmistakably clear that we are fine with linking Free Software - regardless of potential license-version incompatibilities - with Genode.
Please be assured that I'm not careless. In fact, I approached the Free Software Foundation for reviewing my original announcement and incorporated their feedback *before* I sent it to the mailing list.
Regards Norman