On Thu, Jun 03, 2021 at 02:01:13PM -0400, Kenny Ho wrote: > Hi, > > I understand that helper functions available to bpf programs are > listed in include/uapi/linux/bpf.h and kernel headers can be made > available at /sys/kernel/kheaders.tar.xz with CONFIG_IKHEADERS. But > with the support of calling kernel functions from bpf programs, how > would one know which functions are whitelisted? Are the headers for > these whitelisted functions available via something like "bpftool btf > dump file /sys/kernel/btf/vmlinux format c"? Like other whitelisted functions in BPF, the list is not in the vmlinux btf now but could be a BTF extension in the future (Cc: Yonghong). 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?
