Segher Boessenkool <seg...@kernel.crashing.org> writes: > On Fri, Nov 25, 2016 at 09:22:16AM +1100, Michael Ellerman wrote: >> >> >> Question, are there any fundamental reasons we shouldn't use the ELFv2 >> >> >> ABI to build big endian kernels if the compiler supports it? >> >> > >> >> > No one uses ELFv2 for BE in production, and it isn't thoroughly tested >> >> > at all, not even regularly tested. "Not supported", as far as GCC is >> >> > concerned (or any of the distros AFAIK). >> >> >> >> Is this actually unsupported by gcc? >> > >> > It may or may not work. We of course try to keep it working, or make >> > it work if it doesn't now. But it isn't regularly tested, and it isn't >> > a target that is considered for the release criteria (see >> > https://gcc.gnu.org/gcc-7/criteria.html -- powerpc64{,le}-linux, i.e. >> > ABIv1 for BE, ABIv2 for LE). >> >> It doesn't actually say that though. It just says >> powerpc64-unknown-linux-gnu. So how is someone, say the musl folks, >> supposed to know that BE ABIv2 is not supported? > > Because their target is powerpc64*-*-linux-musl instead? It is not on > the release criteria list, it is not something we make any claims about. > > How would you know -m32 -mlittle is not well tested at all? It is in much > the same boat: unusual combinations of options, and unusual configurations, > are not well tested. You have to build a separate C library just to get > started with it, that should tell you there are some rough waters ahead!
Yeah OK, I guess that's the part that's confusing me. Because we're hairy chested kernel programmers we don't actually build a C library at all. So we don't get that hint that we're using an odd combination, we just configure the toolchain, build it and off we go. cheers
