Linus Torvalds has backed the idea of possibly removing Intel 486 (i486) processor support from the Linux kernel.
After the Linux kernel dropped i386 support a decade ago, i486 has been the minimum x86 processor support for the mainline Linux kernel. This latest attempt to kill off i486 support ultimately arose from Linus Torvalds himself with expressing the idea of possible requiring x86 32-bit CPUs with “cmpxchg8b” support, which would mean Pentium CPUs and later.
I think that would be a fair call. It’s highly unlikely any modern additions to the Linux kernel are usable on a 486 anyway, so existing kernels which still have support for this ancient processor should suffice. On top of that, there’s no doubt in my mind that at least someone or some group of people will step up to maintain a special 486 branch if there is indeed any residual need for it.
Agreed. There would be a very narrow need for modern Linux support on 486 hardware.
It has to be a 30+ year old industrial system that needs to run new software, but at the same time could not upgrade the hardware for one reason or another. Or it has to be networked, and needs security updates, but cannot be protected by an external firewall.
Anyway, even the low power chips have moved on to at least the Pentium architecture:
You can always patch the support back in if you need it, indeed. And now I wonder, did anyone patch support for removed architectures (i386 or avr32) into a newer kernel? How much effort would such take? Looking at this case, the support depends on an instruction, thus only a part written in assembly is affected, right?
I’d imagine patching support of variants of a still supported architecture would be some assembler parts. Patching support for a whole removed architecture such as avr32 would take much more effort, as those effect portions of the kernel written in C as well.