* David Abdurachmanov:
We most likely will not have ABIs installed in parallel, but we
might
change ABI. Currently Linux distributions target "RV64GC", but we
don't really want that for the future RISC-V. I keep telling folks
that "RV64GC" is already "a legacy" (10+ years old), but that's
the
major target for the next few years. We are scheduled to see some
RVA22 SBCs this year.
RV64GC -> RVA20 -> RVA22 -> RVA23 -> RVA24.
That's how things evolved. RVA23 most likely will be ratified soonish.
RVA24 is most likely the next major RISC-V Profile from RVI point of
view (TBD). Server specifications are based on RVA23 (and will be
updated to RVA24 [most likely]). This defines baseline ISA, optional
extensions, etc.
Is there really an ABI change, though? That would only happen if the
set of callee-saved registers grows, to include vector registers.
Adding new registers has compatibility problems on its own.
Fedora might want to switch to an ISA baseline that is incompatible with
all currently available CPUs, but that's not necessarily an ABI break as
such.
Thanks,
Florian