Comment by Arnavion

As I said, it's mandatory in RVA23 profile. In fact it has been mandatory since RVA22 profile. A bunch of cores appear to support RVA22.

Whether prebuilt distribution binaries support it or not, I can't tell. Simple glance at Debian and Fedora wiki pages doesn't reveal what profile they target, and I CBA to boot an image in qemu to check. In the worst case they target only GC so they won't have Zba. Source distributions like Gentoo would not have a problem.

In any case, talking about the current level of extension support is moving the goalposts. You countered "there is nothing about the RISC-V architecture which inherently prevents it from ever being competitive with ARM" with "Lack of reg+shifted reg addressing mode", which is an argument about ISA, not implementation.