Currently our configure script allows linux-user targets to be built for "unknown" host CPU architectures (which must be using the TCI interpreter). However, code like user-exec.c has host-architecture #ifdef ladders which in practice mean you can't build linux-user for an arbitrary host architecture. The only two host architectures which have code in user-exec.c but aren't recognised by configure are HPPA and m68k.
I'd like to move to an "every supported host architecture has a linux-user/host/$(ARCH)/hostdep.h header" model (this fixes a problem in the code currently in master where make doesn't notice it needs to rebuild if a host arch moves from "using generic/" to "using $(ARCH)"). Host architectures which we sort-of-but-don't support are an annoying corner case I'd like to be able to drop entirely, by either: (1) just dropping the support outright (2) promoting them to at least being recognised by configure as a known architecture, even if one without a tcg backend Does this seem like a good idea? I think HPPA should definitely be in category (1) -- we dropped the TCG backend years back, and I don't think any of us has a machine to test changes on,. Which category should m68k host support go into? Does anybody actually use m68k host + TCI interpreter linux-user ? My guess is this isn't actually used, because the m68k-specific code in user-exec.c doesn't set the "is_write" flag correctly, which means that guests which do self-modifying code won't work (including anything using a signal handler with an on-stack trampoline). So my preference would be to drop the m68k-host code too. thanks -- PMM
