Historically, the code in arch/ was developed for one architecture and then copied and adjusted by others. This created a lot of duplicated or almost duplicated code with subtle differences which prevents easy refactoring and consolidation.
The linux/arch microconference aims to bring architecture maintainers in one room to discuss how the code in arch/ can be improved, consolidated and generalized, at least where it makes sense.
The discussion at the previous linux/arch microconfernece in 2020 lead to updates in RISC-V kprobes implementation , removal of DISCOTIGMEM memory model  and enablement of generic entry on s390 .
The possible topics could be:
- reducing code duplication and generalizing the common code in arch/
- making headers in include/asm consistent
- on-boarding more architectures to use common entry code
- devicetree (unless they have their own microconf)
- identifying old machine support that may be either still in
active use vs only in hobbyist/retro-computing vs completely
obsolete and broken
Mike Rapoport <email@example.com>, Arnd Bergmann <firstname.lastname@example.org>