Hi Yixun, On 2021/8/12 17:55, Yixun Lan wrote: > HI Xuerui: > > This must be a *HUGE* project and gonna put lots of effort in to it! > So, first, good luck to you with all my best wishes!~ Thanks for your kindness! > > On 00:39 Thu 12 Aug , WANG Xuerui wrote: >> Hi everyone, >> >> I'm your average Gentoo user who obviously thought his sleeping time is more >> than enough, and just decided to start porting Gentoo to LoongArch. As this >> is such a niche architecture with no upstreamed support so far, I'm posting >> this to announce my intent and gather advice on how to best push this. >> >> I'll first give some background material to help people gain context, then >> describe my porting plan. This is going to be a bit long; apologizes for >> that. >> >> >> Note: I'm not affiliated with Loongson in any way; I'm just doing this in my >> spare time (once meant for some quality sleep). >> >> >> ## A bit of introduction on the LoongArch >> >> LoongArch, as its name implies, is the brand-new ISA developed by the >> Loongson Corporation, incompatible with MIPS which was implemented by >> all previous Loongson processors. Currently only the base ISA specification >> is publicly available; it has fixed-length 32-bit instructions, vastly more >> instruction formats (39 distinct formats in the base ISA alone!), and its >> instruction semantics mostly resemble RISC-V, with a bit of MIPS R6 here and >> there. It is capable of 64-bit operations, obviously. >> >> ISA documentation: https://github.com/loongson/LoongArch-Documentation >> ELF psABI draft: https://github.com/loongson/LoongArch-Documentation/pull/3 >> >> The draft ABI is undergoing fierce review, and is subject to change, >> especially the relocation types. Other parts like the register >> convention and >> data layout is unlikely to change much, though. >> >> There is little code upstreamed for basic software (GNU toolchain, QEMU, >> Linux and the like), but many are open-sourced already. Nevertheless, the >> code quality is still very much inferior, and much of it is obviously based >> on respective MIPS support. There is continuous debate inside and outside >> Loongson on this matter, too. >> > Didn't do any investigation, but if I read correctly, also see here [1] > > The fundamental pieces of softwares are open-sourced but *NOT* yet upstreamed > So, I'd say, let's wait till it's actually accepted by upstream, > before pushing to downsteam (Gentoo here). Sure, you're free to send > a pull-request for review/comment, but collect peices under your own overlay > would be a good idea ( in my humble opition ).
Sure; that's basic etiquette. However there are some parts that definitely need upstreaming, otherwise complexity could explode; for example, the multilib_env function and tc-ninja_magic_to_arch function. Without fixing multilib_env we could only use the "default" ABI, and without adapting tc-ninja_magic_to_arch even linux-headers is unable to build. If we don't touch the upstream repo, a full fork is needed, and that's going to be painful. Additionally, I've already seen adaptations for experimental arches in repo; so I thought upstreaming these minimal bits would be acceptable. If that's deemed too early (and I totally understand the reasoning behind that), doing work in forks is okay from my side.
