While building the cross-toolchains, I noticed that overall, we can build almost all linux target architectures with upstream binutils and gcc these days, however there are still some exceptions, and I'd like to find out if anyone has objections to removing the ones that do not have upstream support. This are the four architectures I found: * score (s+core, sunplus core) was a proprietary RISC architecture made by sunplus. It is unclear if they still ship any products based on this architecture, all they list is either ARM Cortex-A9 or an unspecified RISC core that could be any of arm, mips, nds32, arc, xtensa or something completely different. The two maintainers have both left the company many years ago and have not contributed any patches in at least five years. There was an upstream gcc port, which was marked 'obsolete' in 2013 and got removed in gcc-5.0. I conclude that this is dead in Linux and can be removed * unicore32 was a research project at Peking University with a SoC based on the Intel PXA design. No gcc source code has ever been published, the only toolchain available is a set of binaries that include a gcc-4.4 compiler. The project page at http://mprc.pku.edu.cn/~guanxuetao/linux/ has a TODO list that has not been modified since 2011. The maintainer still Acks patches and has last sent a pull request in 2014 and last sent a patch of his own in 2012 when the project appears to have stalled. I would suggest removing this one. * Hexagon is Qualcomm's DSP architecture. It is being actively used in all Snapdragon ARM SoCs, but the kernel code appears to be the result of a failed research project to make a standalone Hexagon SoC without an ARM core. There is some information about the project at https://wiki.codeaurora.org/xwiki/bin/Hexagon/ and https://unix.stackexchange.com/questions/246243/what-is-was-the-qualcomm-hexagon-comet-board There is a port to gcc-4.5 on the project page, which is evidently abandoned, but there is an active upstream LLVM port that is apparently used to build non-Linux programs. I would consider this one a candidate for removal as well, given that there were never any machines outside of Qualcomm that used this, and they are no longer interested themselves. * Meta was ImgTec's own architecture and they upstreamed the kernel port just before they acquired MIPS. Apparently Meta was abandoned shortly afterwards and disappeared from imgtec's website in 2014. The maintainer is still fixing bugs in the port, but I could not find any toolchain more recent than https://github.com/img-meta/metag-buildroot/tree/metag-core/toolchain/gcc/4.2.4 Not sure about this one, I'd be interested in more background from James Hogan, who probably has an opinion and might have newer toolchain sources. * OpenRISC is a RISC architecture with a free license and an active community. It seems to have lost a bit of steam after RISC-V is rapidly taking over that niche, but there are chips out there and the design isn't going away. Listing it here for completeness only because there is no upstream gcc port yet, but this will hopefully change in the future based on https://lists.librecores.org/pipermail/openrisc/2018-January/000958.html and I had no problems locating the gcc-7.x tree for building my toolchains. The port is actively being maintained. There are also a couple of architectures that are more or less unmaintained but do have working gcc support: FR-V and M32R have been orphaned for a while and are not getting updated MN10300 is still maintained officially by David Howells but doesn't seem any more active than the other two, the last real updates were in 2013. Arnd
