The RISC-V RVA23 profile is a big deal for reducing fragmentation in the RISC-V ecosystem and standardizing more of the ISA to make it easier to distribute modern RISC-V binaries and the like. Modern versions of Ubuntu mandate RVA23 even though compliant hardware is still quite limited. Somewhat surprisingly, only coming about now is an easy ability for Linux users to find the answer to "is my RISC-V system RVA23 compliant?" Pending Linux kernel patches are finally offering a one-shot way of telling you.

Currently for user-space programs or users to find out if their RISC-V system is RVA23 compliant, they need to check hwprobe or prctl queries for every mandatory extension of RVA23. There hasn't been a one-shot way for the Linux kernel to report RVA23 support. Qualcomm engineer Guodong Xu has been working to address that gap to expose RVA23U64 base behavior via hwprobe. In turn this RVA23 support is also communicated via the likes of /proc/cpuinfo and hwprobe to make it easy to determine RISC-V RVA23 support on a given system.

This was discussed further at the Linux Plumbers Conference last week in Prague and appears on a trajectory for finally making it to the mainline kernel. Guodong Xu has blogged about the effort for those interested.

Much of the patch series is now queued in RISC-V's for-next Git branch for Linux 7.4. But the RVA23U64 bit reporting patches are being reworked for at least one more round of code review before going mainline. We'll see if it happens for v7.4 or is held off for another version, but at least it's getting close for this easy RVA23 reporting to user-space.