On Mon, Dec 27, 2021 at 4:31 AM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Sun, Dec 26, 2021 at 7:38 AM Guo Ren <guoren@xxxxxxxxxx> wrote: > > On Sun, Dec 26, 2021 at 4:36 PM Jisheng Zhang <jszhang3@xxxxxxxxxxxxxxxx> wrote: > > > On Wed, 22 Dec 2021 20:59:30 +0800 Guo Ren <guoren@xxxxxxxxxx> wrote: > > > > On Wed, Dec 22, 2021 at 2:10 AM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > > > > What about adding RV64 ILP32 support instead? This don't need HW side > > > modifications so can benefit all RV64. > > > > ILP32 is another topic in C Language Data Type Models and it couldn't > > replace the standard rv32 ecosystem. > > COMPAT is a common framework in Linux (7 arches have been supported), > > so let rv64 support COMPAT mode is considerable. > > > > Customers would choose ILP32 / RV32-compat by themself and that > > depends on which one has a better ecosystem. > > From a kernel perspective, supporting both is not much more work than > supporting either of them. We had the same debate for Arm64, and ended > up never merging the ILP32 patches despite them being well written > and maintainable, to limit the number of supported user space ABIs > as well as the possible attack vectors when there is an exploitable > bug that is specific to an ABI. > > arm64 does support big-endian mode, which is a similar niche, but it > can't easily be removed after it's already supported. Supporting normal > compat mode is the easiest here because it doesn't add another user > space ABI, but I'd strongly recommend not to add any other ones. @Palmer Dabbelt How do you think about supporting ILP32 & COMPAT both in rv64? And let users vote by foot which is better. > > Arnd -- Best Regards Guo Ren ML: https://lore.kernel.org/linux-csky/
