Re: [PATCH bpf-next v2] riscv, bpf: Add kfunc support for RV64

[Pu Lehui]

On 2023/2/21 15:02, Björn Töpel wrote:
> Pu Lehui <pulehui@xxxxxxxxxxxxxxx> writes:
>
> > On 2023/2/20 22:34, Björn Töpel wrote:
> > > Pu Lehui <pulehui@xxxxxxxxxxxxxxx> writes:
> > >
> > > > From: Pu Lehui <pulehui@xxxxxxxxxx>
> > > >
> > > > As another important missing piece of RV64 JIT, kfunc allow bpf programs
> > > > call kernel functions. For now, RV64 is sufficient to enable it.
> > >
> > > Thanks Lehui!
> > >
> > > Maybe we can reword/massage the commit message a bit? What do you think
> > > about something like:
> > >
> > > "Now that the BPF trampoline is supported by RISC-V, it is possible to
> > > use BPF programs with kfunc calls.
> >
> > kfunc and bpf trampoline are functionally independent. kfunc [1], like
> > bpf helper functions, allows bpf programs to call exported kernel
> > functions, while bpf trampoline provides a more efficient way than
> > kprobe to act as a mediator between kernel functions and bpf programs,
> > and between bpf programs.
> >
> > In fact, it was already supported before the bpf trampoline
> > implementation, I just turned it on.
>
> Good point. I guess my (incorrect) kfunc mental model was that
> struct_ops and kfunc were tightly coupled. (Then again, w/o struct_ops
> working kfunc is a bit half-working in my view.)
>
> Fair enough. I'm still a bit confused about the commit message, but
> happy with the patch.
>  > Acked-by: Björn Töpel <bjorn@xxxxxxxxxxxx>

Thanks Bjorn, will rewrite commit message to make more sense, and send 
new soon.