[LSF/MM/BPF TOPIC] Support more than 5 parameters in bpf

[Yonghong Song <yonghong.song@linux.dev>]

Currently, bpf function calls and kfunc's are limited by 5 reg-level
parameters. For function calls with more than 5 parameters,
developers can use always inlining or pass a struct pointer
after packing more parameters in that struct. But there is
no workaround for kfunc if more than 5 parameters is needed.

I started to explore how to support more than 5 parameters
for bpf prog function calls and kfuncs. This involves both llvm
and kernel bpf. I would like to present my findings
at LSF/MM/BPF.

Thanks!