I would think the bigger problems are drivers & secure boot rather than just instructions. M1 is a regular ARM processor so existing backends at a minimum would work fine even if they're not fully optimized (+ I would be a bit surprised if the M1 support for LLVM isn't upstreamed).
Is that really true that M1 is just an ARM processor? I've heard the difficulty in emulating it is due to Apple specific things, whether they be drivers or new instructions.
If you have code that makes use of custom instructions, even if only sprinkled in a few places, the emulator must support them.
If you have a cpu with those extra instructions that is otherwise backwards compatible, you can run code that doesn't make use of such instructions just fine (of course, you won't benefit from the functionality/performance offered by those new instructions)
I understood this thread to be about running Linux bare metal natively on the M1, so there's no emulation there & new instructions don't matter. Drivers & secure boot are always the biggest problem. It sounds like you can sign your own kernel & add it so in theory secure boot may not be a problem. Then the question is which driver support are missing & need implementation & how close that lines up with existing ARM device trees.
> This work, especially as there's no exploiting security bugs required here, will benefit Linux on those Macs quite a lot.
Right, it sounds like Apple was very careful to provide an out here for enthusiasts by making it possible to sign your own kernel, something you can't do for iPhone/iPad/Watch. Seems like an astute appreciation of differences in their target market.
