RISCstar toolchain 15.2-r1 has been released

Toolchain
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At the RISC-V Summit North America, RISCstar announced the release of the latest version of the RISCstar toolchain for RISC-V.

The toolchain is based around gcc 15.2 supported by binutils 2.45 and gdb 16.3. Depending on the toolchain edition you will also find linux 6.5 kernel headers, glibc 2.38, musl 1.2.5 and/or newlib 4.5.

Note that 15.2-r1 is the first release where the RISC-V hosted compilers require RVA23. Learn more about the RISCstar toolchain at the RISCstar blog.

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I noticed in 15.2-r1 (October 2025) release, the native toolchain is for “For RISC-V (RVA23U64 and later) hosts“, however, the 15.1-rc1 (July 2025) it is for “For RISC-V (RV64GC and later) hosts“. I wonder is there any special notes which I (as a user) should be aware of. Given the fact that RVA23U64 board is not available yet, should I avoid using it?

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I hope the rest of https://riscstar.com/toolchain is also clear that we intend the toolchain for RISC-V to support only RVA23. It’s not supposed to be a secret!

Others are very welcome to disagree but I personally think RVA23 marks such an important shift in the ecosystem that it’s better to baseline on this than to have needlessly slow compilers when RVA23 hardware arrives. As you observed we ship a couple of older versions of the toolchain where the native builds target RV64GC. That is offered just in case people with pre-RVA23 hardware really need them for comparative benchmarking and so on..

Finally, just in case there is any doubt, the toolchain itself can build binaries for whatever profile you want. The bundled libraries for the Linux toolchains are built for RV64GC but, in most cases, you’ll be dynamically linking anyway so the libraries you get at runtime are whatever comes from the distro you are running on the target board.

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Actually, I nearly forgot.

There is actually a “secret” here (so don’t tell anyone :wink: ). The RVA23U64 binaries are actually built for rv64gcv_zicond_zba_zbb_zbs. This is not quite as aggressive as RVA23 and there is real hardware that can run the binaries today.

To be extremely clear this was a convenience for testing rather than some clever plan. The default build settings will change once real RVA23 hardware becomes available so don’t expect to be able to run later versions of the RISCstar toolchain on non-RVA23 hardware. That’s why it’s not documented and will remain so.

Again however, its absolutely fine to take advantage of this information for tasks like benchmarking.

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