Andrii Nakryiko <andrii@xxxxxxxxxx> writes: > Drop the requirement for system-wide kernel UAPI headers to provide full > struct btf_enum64 definition. This is an unexpected requirement that > slipped in libbpf 1.0 and put unnecessary pressure ([0]) on users to have > a bleeding-edge kernel UAPI header from unreleased Linux 6.0. > > To achieve this, we forward declare struct btf_enum64. But that's not > enough as there is btf_enum64_value() helper that expects to know the > layout of struct btf_enum64. So we get a bit creative with > reinterpreting memory layout as array of __u32 and accesing lo32/hi32 > fields as array elements. Alternative way would be to have a local > pointer variable for anonymous struct with exactly the same layout as > struct btf_enum64, but that gets us into C++ compiler errors complaining > about invalid type casts. So play it safe, if ugly. > > [0] Closes: https://github.com/libbpf/libbpf/issues/562 > > Reported-by: Toke Høiland-Jørgensen <toke@xxxxxxx> > Fixes: d90ec262b35b ("libbpf: Add enum64 support for btf_dump") > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> This seems like a reasonable (and only a bit ugly) workaround; thanks! Acked-by: Toke Høiland-Jørgensen <toke@xxxxxxx>
