[ajross]

Pedantry: but RISC-V is open hardware only from the logic level up.

The "transistor" level would require open source silicon layout software, and probably some level of NDA relaxation on the part of the fabs who surely won't allow a production mask set on their modern[1] processes to be released to the public. I don't see that happening any time soon.

[1] Mature/legacy processes actually do have public design rules available. The MOSIS "scalable CMOS" rules apparently work for real devices at the 180nm node or thereabouts.

[skissane]

I wonder, if the logic level was copyrighted under a sharealike license such as GPL, and the mask is a derivative work, does that make the mask subject to the sharealike license too? (I know that there exist "mask work rights" as a separate legal category from copyrights, but I'm not sure how a mask work right would interact with a sharealike copyright license...)

[ajross]

My informed amateur opinion is that no one really knows. There's no case law on this that I'm aware of.

Basically: the "shape of a transistor" (and highly tuned structures like SRAM & flash cells, etc...) in modern logic processes is itself a tightly guarded secret. Outside some crappy electron microcroscopy done by people like Chipworks and the much-prettier-but-really-spun pictures released by the fab's marketing departments, no one involved in the process releases anything.

Now, maybe that's because it's that the masks are ultimately copyrighted by the fab and protected. Or maybe if they leaked they'd be perfectly fine. But what really happens in practice is that before the fab will consent to make your chips for you, they force you to sign an elaborate NDA with no doubt huge contractual penalties.

Again, I don't expect this to change. Silicon fabrication at the mask level will not be open source any time soon, though maybe there's hope that open source tooling might arrive. We just won't be able to see its output.

[BuuQu9hu]

Hardware isn't subject to copyright. There are places in China that can reverse engineer boards from hardware back to design files, so GPLing board designs is pretty pointless.

There are patents, but they don't protect designs or individual physical items, just processes.

There is IC mask protection, but that doesn't protect modified versions of the IC masks (if I understand it correctly):

https://en.wikipedia.org/wiki/Integrated_circuit_layout_desi...