RISC-V With Linux 6.0 Improves Svpbmt, More Useful Default Kernel Configuration

Each new kernel cycle there continues to be more maturity to the RISC-V processor architecture code. With Linux 6.0 there are a few new features wired up as well as bug fixes / clean-ups.

The RISC-V code in Linux 6.0 improves its Svpbmt support, which is the RISC-V extension for Page-Based Memory Types. Svpbmt has been worked on for the Linux kernel since earlier in the year with this extension defining behavior around non-cacheable pages, I/O memory pages, etc. Svpbmt was added in Linux 5.19 and now further improved upon for the 6.0 cycle.

The Linux 6.0 RISC-V changes also include a more useful default configuration "defconfig". The Linux 6.0 RISC-V defconfig now enables enough features out-of-the-box that Docker can be run without issues. Additionally, more of the kernel features needed for Ubuntu's Snaps are also present. That earlier article has more details on the particular kernel features now flipped on for the RISC-V defconfig.

Other RISC-V patches for Linux 6.0 include CPU topology bindings for a few more systems, support for systems with 64-bit hart IDs, and other clean-ups and improvements.

All the details on the RISC-V code churn for Linux 6.0 via this pull request that has already landed in master.

Unrelated to RISC-V for the Linux kernel, but in other RISC-V news sitting in my queue, Mold 1.4 released this week. Mold is the high performance linker alternative to GNU Gold and LLVM's LLD while with the new Mold 1.4 has added RISC-V 32-bit support.