On 2024/2/2 0:19, Alexei Starovoitov wrote:
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/
OK, will keep tracking.
