From: Alexei Starovoitov ast@kernel.org
[ Upstream commit 7c6a469e3416fa23568c2395a3faa7dd6e376dcb ]
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 Stable-dep-of: 178c54666f9c ("bpf: Mark bpf_spin_{lock,unlock}() helpers with notrace correctly") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/filter.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h index 440014875acf4..11407e9e606db 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -479,10 +479,11 @@ static inline bool insn_is_zext(const struct bpf_insn *insn) #define BPF_CALL_x(x, name, ...) \ static __always_inline \ u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \ + typedef u64 (*btf_##name)(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \ u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)); \ u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)) \ { \ - return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\ + return ((btf_##name)____##name)(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\ } \ static __always_inline \ u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))