Re: [PATCH bpf-next v1 0/4] Support bpf trampoline for RV64

[Pu Lehui]

On 2023/2/15 22:45, Björn Töpel wrote:
> Hi Lehui,
>
> Pu Lehui <pulehui@xxxxxxxxxxxxxxx> writes:
>
> > BPF trampoline is the critical infrastructure of the bpf
> > subsystem, acting as a mediator between kernel functions
> > and BPF programs. Numerous important features, such as
> > using ebpf program for zero overhead kernel introspection,
> > rely on this key component. We can't wait to support bpf
> > trampoline on RV64. Since RV64 does not support ftrace
> > direct call yet, the current RV64 bpf trampoline is only
> > used in bpf context.
>
> Thanks a lot for continuing this work. I agree with you that it's
> valuable to have BPF trampoline support, even without proper direct call
> support (we'll get there soon). The trampoline enables kfunc calls. On
> that note; I don't see that you enable "bpf_jit_supports_kfunc_call()"
> anywhere in the series.  With BPF trampoline support, the RISC-V BPF
> finally can support kfunc calls!
>
> I'd add the following to bpf_jit_comp64.c:

happy to hear that，let's make it more completeable.

> bool bpf_jit_supports_kfunc_call(void)
> {
>          return true;
> }
>
> :-)
>
> I'll do a review ASAP.
>
>
> Björn