On Fri, Jun 4, 2021 at 4:47 PM Kenny Ho <y2kenny@xxxxxxxxx> wrote: > > 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. Yonghong and Martin, does the use case make sense? Or am I trying to do something stupid? Kenny
