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. As for RV32 kfunc, it needs to do
some registers parsing.
[1] https://lore.kernel.org/bpf/20210325015124.1543397-1-kafai@xxxxxx/
Note that the trampoline functionality is only supported by RV64.
Add bpf_jit_supports_kfunc_call() to the 64-bit JIT."
Björn
