On Fri, Jun 4, 2021 at 12:11 PM Yonghong Song <yhs@xxxxxx> wrote: > On 6/3/21 11:13 PM, Martin KaFai Lau wrote: > > > > Making the kfunc call whitelist more accessible is useful in general. > > The bpf tcp-cc struct_ops is the only prog type supporting kfunc call. > > What is your use case to introspect this whitelist? > > Agree. It would be good if you can share your use case. At the high level, I am trying to see if we can use bpf in the drm subsystem and gpu drivers which are kernel modules. My initial motivation was to use bpf for dynamic/run-time reconfiguration of the drm/gpu driver (for experimentation.) But now that I learned more about bpf, I think there are quite a few more things I can do with it. (Debugging during GPU hw bring-ups, profiling driver performance in live system, etc.) I have been looking into bpf with kprobe and struct_ops. In terms of kernel module support for bpf/btf, Andrii told me about it last year and I see that his feature is in (I was able to do a btf dump file for /sys/kernel/btf/amdgpu, /sys/kernel/btf/drm_ttm_helper, for example.) The next thing I thought about was having helper functions from kernel modules and Toke pointed me to Martin's patch around "unstable helpers"/calling whitelisted kernel functions and this is where we are at.
