arm64 kernels don't have BTF #80
Description
The amd64 kernel contains BTF as expected. But the arm64 kernel does not.
Would it be possible to add BTF in the arm64 kernel too?
$ skopeo copy --multi-arch all docker://ghcr.io/cilium/ci-kernels:stable-debug oci-archive:image.tar:ghcr.io/cilium/ci-kernels:stable-debug
$ tar xf image.tar
$ mkdir amd64 arm64
$ tar -C amd64/ -xf blobs/sha256/04823e48009fd0d990e88bd9d67a4d25bcb3a08db6d4a9fbaa75077b1d1dcc44
$ tar -C arm64/ -xf blobs/sha256/69edc719ab0fe4fdace893d32f68ac9b9963efa8900f119a868ea4cf4a702d68
$ file amd64/boot/vmlinux arm64/boot/vmlinux
amd64/boot/vmlinux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, BuildID[sha1]=a99b6e10ab0c25b625e98c653070785adfd9157d, with debug_info, not stripped
arm64/boot/vmlinux: ELF 64-bit LSB pie executable, ARM aarch64, version 1 (SYSV), statically linked, BuildID[sha1]=65b52e94a446c54ac7a70c64b30d14c75a98159f, with debug_info, not stripped
$ bpftool btf dump file amd64/boot/vmlinux format c|head -2
#ifndef __VMLINUX_H__
#define __VMLINUX_H__
$ bpftool btf dump file arm64/boot/vmlinux format c|head -2
libbpf: failed to find '.BTF' ELF section in arm64/boot/vmlinux
Error: failed to load BTF from arm64/boot/vmlinux: No data available
$ objdump -h amd64/boot/vmlinux|grep -i btf
13 .BTF 003f2b96 ffffffff822d19e4 00000000022d19e4 014d19e4 2**0
14 .BTF_ids 00000e84 ffffffff826c457c 00000000026c457c 018c457c 2**0
$ objdump -h arm64/boot/vmlinux|grep -i btf
$
The build logs of the GitHub Action contains:
2025-07-04T18:37:57.2707152Z #11 [linux/amd64->arm64 configure-vmlinux 7/7] RUN ./configure-vmlinux.sh
2025-07-04T18:37:57.2707898Z #11 8.282 Ignoring unrecognised option CONFIG_UPROBE_EVENT
2025-07-04T18:37:57.2708541Z #11 8.283 Ignoring unrecognised option CONFIG_MEDIA_RC_SUPPORT
2025-07-04T18:37:57.2710135Z #11 8.283 Ignoring unrecognised option CONFIG_DEBUG_INFO_BTF_MODULES
2025-07-04T18:37:57.2710876Z #11 8.283 Ignoring unrecognised option CONFIG_DEBUG_INFO_BTF
2025-07-04T18:37:57.2711479Z #11 8.283 Ignoring unrecognised option CONFIG_BPFILTER