Re: [PATCH] bpf: Added linker support for R_BPF_64_NODYLD32.

["Jose E. Marchesi" <jose.marchesi@oracle.com>]

Hi Cuper.

> Hi everyone,
>
> This patch is in context of Nick Cliftons request in thread:
>   https://sourceware.org/pipermail/binutils/2023-October/130194.html
> due to bug reported in:
>   https://bugzilla.redhat.com/show_bug.cgi?id=2245296
>
> For the time being the linker is not used in BPF infrastructure.
> Considering that and without a proper way to validate the code, the
> following patch is what I think is missing in order to add linker
> support for the particular relocation.
>
> Looking forward to your review.
>
> Best regards,
> Cupertino
>
> This patch adds linker support to patch R_BPF_64_NODYLD32 relocations.
> The implementation was based on comments and code in LLVM, as the GNU
> toolchain does not uses this relocation type.
> ---
>  bfd/elf64-bpf.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/bfd/elf64-bpf.c b/bfd/elf64-bpf.c
> index aefad7da5ac..5820dd3d7d4 100644
> --- a/bfd/elf64-bpf.c
> +++ b/bfd/elf64-bpf.c
> @@ -276,6 +276,7 @@ bpf_elf_relocate_section (bfd *output_bfd ATTRIBUTE_UNUSED,
>            }
>  	case R_BPF_64_ABS64:
>  	case R_BPF_64_ABS32:
> +	case R_BPF_64_NODYLD32:

I would add here a comment explaining that R_BPF_64_NODYLD32 shall be
handled/resolved like R_BPF_64_ABS32 and that it differs from ABS32 only
in that the LLVM execution engine is not supposed to resolve it.

Given that, the patch is OK.
Thanks!

>  	  {
>  	    addend = bfd_get (howto->bitsize, input_bfd, where);
>  	    relocation += addend;