On Thu, Feb 1, 2024 at 2:56 AM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > > > will be destroyed. So we implemented mixing bpf2bpf and tailcalls > > similar to x86_64, i.e. using a non-callee saved register to transfer ... > Iiuc, this still needs a respin as per the ongoing discussions. Also, > if you have worked on BPF selftests which exercise the corner case > around a6, please include them in the series as well for coverage. Hold on, folks. I'm not sure it's such a code idea to support tailcalls from subprogs in risc-v. They're broken on x86-64 and so far several attempts to fix them were not successful. If we don't have a fix soon we will disable this feature completely in the verifier. In general tailcalling from subprogs is a niche use case. If there are users they should transition to tail call from main prog only. See https://lore.kernel.org/bpf/CAADnVQJ1szry9P00wweVDu4d0AQoM_49qT-_ueirvggAiCZrpw@xxxxxxxxxxxxxx/
