bpf: Add typecast to bpf helpers to help BTF generation
authorAlexei Starovoitov <ast@kernel.org>
Wed, 16 Oct 2019 03:24:56 +0000 (20:24 -0700)
committerDaniel Borkmann <daniel@iogearbox.net>
Thu, 17 Oct 2019 14:44:35 +0000 (16:44 +0200)
commit7c6a469e3416fa23568c2395a3faa7dd6e376dcb
tree522ea704e48e044ab6a643025e1a84c4ec3ede56
parente8c423fb31fa8b1ef6d7cd14a168de33e7c0d702
bpf: Add typecast to bpf helpers to help BTF generation

When pahole converts dwarf to btf it emits only used types.
Wrap existing bpf helper functions into typedef and use it in
typecast to make gcc emits this type into dwarf.
Then pahole will convert it to btf.
The "btf_#name_of_helper" types will be used to figure out
types of arguments of bpf helpers.
The generated code before and after is the same.
Only dwarf and btf sections are different.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191016032505.2089704-3-ast@kernel.org
include/linux/filter.h