On Mon, Feb 22, 2021 at 5:20 PM Kun-Chuan Hsieh <jetswayss@xxxxxxxxx> wrote:
>
> Older versions of libelf cannot recognize the compressed section.
> However, it's only required to fix the compressed section info when
> compiling with CONFIG_DEBUG_INFO_COMPRESSED flag is set.
Is it possible to detect (at compilation time or at run time) if
libelf supports compressed ELF sections instead?
>
> Only compile the compressed_section_fix function when necessary will make
> it easier to enable the BTF function. Since the tool resolve_btfids is
> compiled with host toolchain. The host toolchain might be older than the
> cross compile toolchain.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Kun-Chuan Hsieh <jetswayss@xxxxxxxxx>
> ---
> tools/bpf/resolve_btfids/main.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
> index 7409d7860aa6..ad40346c6631 100644
> --- a/tools/bpf/resolve_btfids/main.c
> +++ b/tools/bpf/resolve_btfids/main.c
> @@ -260,6 +260,7 @@ static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
> return btf_id__add(root, id, false);
> }
>
> +#ifdef CONFIG_DEBUG_INFO_COMPRESSED
> /*
> * The data of compressed section should be aligned to 4
> * (for 32bit) or 8 (for 64 bit) bytes. The binutils ld
> @@ -292,6 +293,7 @@ static int compressed_section_fix(Elf *elf, Elf_Scn *scn, GElf_Shdr *sh)
> }
> return 0;
> }
> +#endif
>
> static int elf_collect(struct object *obj)
> {
> @@ -370,8 +372,10 @@ static int elf_collect(struct object *obj)
> obj->efile.idlist_addr = sh.sh_addr;
> }
>
> +#ifdef CONFIG_DEBUG_INFO_COMPRESSED
> if (compressed_section_fix(elf, scn, &sh))
> return -1;
> +#endif
> }
>
> return 0;
> --
> 2.25.1
>
