On Fri, Oct 4, 2019 at 10:05 PM Alexei Starovoitov <ast@xxxxxxxxxx> wrote:
>
> When pahole converts dwarf to btf it emits only used types.
> Wrap existing __bpf_trace_##template() function into
> btf_trace_##template typedef and use it in type cast to
> make gcc emits this type into dwarf. Then pahole will convert it to btf.
> The "btf_trace_" prefix will be used to identify BTF enabled raw tracepoints.
>
> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> ---
Acked-by: Andrii Nakryiko <andriin@xxxxxx>
> include/trace/bpf_probe.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
> index d6e556c0a085..ff1a879773df 100644
> --- a/include/trace/bpf_probe.h
> +++ b/include/trace/bpf_probe.h
> @@ -74,11 +74,12 @@ static inline void bpf_test_probe_##call(void) \
> { \
> check_trace_callback_type_##call(__bpf_trace_##template); \
> } \
> +typedef void (*btf_trace_##template)(void *__data, proto); \
> static struct bpf_raw_event_map __used \
> __attribute__((section("__bpf_raw_tp_map"))) \
> __bpf_trace_tp_map_##call = { \
> .tp = &__tracepoint_##call, \
> - .bpf_func = (void *)__bpf_trace_##template, \
> + .bpf_func = (void *)(btf_trace_##template)__bpf_trace_##template, \
> .num_args = COUNT_ARGS(args), \
> .writable_size = size, \
> };
> --
> 2.20.0
>
