Loongson Volleys Latest Patches For LoongArch Linux Support

Chinese vendor Loongson continues working on their Linux kernel patches enabling the LoongArch processor ISA as their fork from MIPS. While early on when copying existing MIPS open-source code they were quick to call their new ISA "not MIPS", in these later patch series they continue to refer to their ISA as "a bit like MIPS or RISC-V."

LoongArch debuted this summer with their Loongson 3A5000 processors and since then their engineers have been working to get the LoongArch support into the mainline kernel. Loongson though has ruffled some feathers of the upstream kernel developers with in some areas just copying existing MIPS code.

Loongson did recently begin providing some documentation on their ISA that shows it isn't a 1:1 copy of MIPS, but rather based on it with various changes. Out this morning are the v5 patches for LoongArch. With these new patches the code has been based against the latest upstream Linux 5.15 state, there are various fixes, the system call and ptrace code has been adjusted, and a variety of other changes.

With this particular patch series it's roughly 23k lines of new kernel code, including documentation and Kconfig additions.

We'll see how this work goes and when it's ready for the mainline kernel.