linux-stable/samples/bpf
Jakub Kicinski be3158290d Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Andrii Nakryiko says:

====================
bpf-next 2021-12-10 v2

We've added 115 non-merge commits during the last 26 day(s) which contain
a total of 182 files changed, 5747 insertions(+), 2564 deletions(-).

The main changes are:

1) Various samples fixes, from Alexander Lobakin.

2) BPF CO-RE support in kernel and light skeleton, from Alexei Starovoitov.

3) A batch of new unified APIs for libbpf, logging improvements, version
   querying, etc. Also a batch of old deprecations for old APIs and various
   bug fixes, in preparation for libbpf 1.0, from Andrii Nakryiko.

4) BPF documentation reorganization and improvements, from Christoph Hellwig
   and Dave Tucker.

5) Support for declarative initialization of BPF_MAP_TYPE_PROG_ARRAY in
   libbpf, from Hengqi Chen.

6) Verifier log fixes, from Hou Tao.

7) Runtime-bounded loops support with bpf_loop() helper, from Joanne Koong.

8) Extend branch record capturing to all platforms that support it,
   from Kajol Jain.

9) Light skeleton codegen improvements, from Kumar Kartikeya Dwivedi.

10) bpftool doc-generating script improvements, from Quentin Monnet.

11) Two libbpf v0.6 bug fixes, from Shuyi Cheng and Vincent Minet.

12) Deprecation warning fix for perf/bpf_counter, from Song Liu.

13) MAX_TAIL_CALL_CNT unification and MIPS build fix for libbpf,
    from Tiezhu Yang.

14) BTF_KING_TYPE_TAG follow-up fixes, from Yonghong Song.

15) Selftests fixes and improvements, from Ilya Leoshkevich, Jean-Philippe
    Brucker, Jiri Olsa, Maxim Mikityanskiy, Tirthendu Sarkar, Yucong Sun,
    and others.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (115 commits)
  libbpf: Add "bool skipped" to struct bpf_map
  libbpf: Fix typo in btf__dedup@LIBBPF_0.0.2 definition
  bpftool: Switch bpf_object__load_xattr() to bpf_object__load()
  selftests/bpf: Remove the only use of deprecated bpf_object__load_xattr()
  selftests/bpf: Add test for libbpf's custom log_buf behavior
  selftests/bpf: Replace all uses of bpf_load_btf() with bpf_btf_load()
  libbpf: Deprecate bpf_object__load_xattr()
  libbpf: Add per-program log buffer setter and getter
  libbpf: Preserve kernel error code and remove kprobe prog type guessing
  libbpf: Improve logging around BPF program loading
  libbpf: Allow passing user log setting through bpf_object_open_opts
  libbpf: Allow passing preallocated log_buf when loading BTF into kernel
  libbpf: Add OPTS-based bpf_btf_load() API
  libbpf: Fix bpf_prog_load() log_buf logic for log_level 0
  samples/bpf: Remove unneeded variable
  bpf: Remove redundant assignment to pointer t
  selftests/bpf: Fix a compilation warning
  perf/bpf_counter: Use bpf_map_create instead of bpf_create_map
  samples: bpf: Fix 'unknown warning group' build warning on Clang
  samples: bpf: Fix xdp_sample_user.o linking with Clang
  ...
====================

Link: https://lore.kernel.org/r/20211210234746.2100561-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-10 15:56:13 -08:00
..
.gitignore samples/bpf: Update .gitignore 2021-10-08 11:58:58 -07:00
asm_goto_workaround.h samples/bpf: Add a workaround for asm_inline 2019-10-03 17:37:11 +02:00
bpf_insn.h samples/bpf: Relicense bpf_insn.h as GPL-2.0-only OR BSD-2-Clause 2021-09-29 16:03:55 +02:00
cookie_uid_helper_example.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
cpustat_kern.c samples: bpf: Refactor tracepoint tracing programs with libbpf 2020-08-24 20:59:35 -07:00
cpustat_user.c samples: bpf: Refactor tracepoint tracing programs with libbpf 2020-08-24 20:59:35 -07:00
do_hbm_test.sh samples: bpf: Fix a spelling typo in do_hbm_test.sh 2021-03-15 22:17:35 -07:00
fds_example.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
hash_func01.h samples/bpf: add Paul Hsieh's (LGPL 2.1) hash function SuperFastHash 2018-08-10 16:07:49 +02:00
hbm.c samples: bpf: Refactor hbm program with libbpf 2020-11-26 19:33:35 -08:00
hbm.h bpf: Add more stats to HBM 2019-05-31 16:41:29 -07:00
hbm_edt_kern.c bpf: Add support for fq's EDT to HBM 2019-07-03 15:03:00 +02:00
hbm_kern.h samples/bpf: Clean up samples/bpf build failes 2021-12-02 15:23:40 -08:00
hbm_out_kern.c bpf: Add more stats to HBM 2019-05-31 16:41:29 -07:00
ibumad_kern.c samples: bpf: Ix kernel-doc syntax in file header 2021-05-24 21:06:02 -07:00
ibumad_user.c samples: bpf: Ix kernel-doc syntax in file header 2021-05-24 21:06:02 -07:00
lathist_kern.c samples: bpf: Refactor kprobe tracing programs with libbpf 2020-08-24 20:59:35 -07:00
lathist_user.c samples: bpf: Refactor kprobe tracing programs with libbpf 2020-08-24 20:59:35 -07:00
lwt_len_hist.sh samples: bpf: Fix lwt_len_hist reusing previous BPF map 2020-11-26 19:33:36 -08:00
lwt_len_hist_kern.c samples/bpf: Clean up samples/bpf build failes 2021-12-02 15:23:40 -08:00
lwt_len_hist_user.c samples: bpf: Fix build error 2020-05-14 12:37:39 -07:00
Makefile samples: bpf: Fix xdp_sample_user.o linking with Clang 2021-12-06 19:33:44 -08:00
Makefile.target samples/bpf: Clean up samples/bpf build failes 2021-12-02 15:23:40 -08:00
map_perf_test_kern.c samples: bpf: Refactor BPF map performance test with libbpf 2020-07-08 01:33:14 +02:00
map_perf_test_user.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
offwaketime_kern.c samples/bpf: Define MAX_ENTRIES instead of a magic number in offwaketime 2021-08-15 00:08:40 -07:00
offwaketime_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
parse_ldabs.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
parse_simple.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
parse_varlen.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
README.rst bpf, docs: Update build procedure for manually compiling LLVM and Clang 2021-01-23 00:09:03 +01:00
run_cookie_uid_helper_example.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sampleip_kern.c bpf: Remove unused headers 2021-03-25 22:03:46 -07:00
sampleip_user.c samples, bpf: Refactor pointer error check with libbpf 2020-05-19 17:12:49 +02:00
sock_example.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
sock_example.h samples: bpf: include bpf/bpf.h instead of local libbpf.h 2018-05-14 22:52:10 -07:00
sock_flags_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
sockex1_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
sockex1_user.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
sockex2_kern.c samples/bpf: Remove compiler warnings 2020-05-13 12:30:50 -07:00
sockex2_user.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
sockex3_kern.c bpf, libbpf: Guard bpf inline asm from bpf_tail_call_static 2020-10-22 01:46:52 +02:00
sockex3_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
spintest_kern.c samples: bpf: Refactor kprobe tracing programs with libbpf 2020-08-24 20:59:35 -07:00
spintest_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
syscall_nrs.c samples: bpf: syscall_nrs: use mmap2 if defined 2019-08-21 14:31:38 +02:00
syscall_tp_kern.c samples: bpf: Refactor tracepoint tracing programs with libbpf 2020-08-24 20:59:35 -07:00
syscall_tp_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
task_fd_query_kern.c samples: bpf: Fix broken bpf programs due to removed symbol 2020-08-18 17:10:03 -07:00
task_fd_query_user.c samples, bpf: Suppress compiler warning 2021-05-12 12:29:43 -07:00
tc_l2_redirect.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tc_l2_redirect_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tc_l2_redirect_user.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 206 2019-05-30 11:29:53 -07:00
tcbpf1_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_basertt_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_bpf.readme samples/bpf: fix tcp_bpf.readme detach command 2019-07-03 16:52:02 +02:00
tcp_bufs_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_clamp_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_cong_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_dumpstats_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_iw_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_rwnd_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_synrto_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tcp_tos_reflect_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
test_cgrp2_array_pin.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
test_cgrp2_attach.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
test_cgrp2_sock.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
test_cgrp2_sock.sh samples/bpf: detach prog from cgroup 2018-03-02 00:16:36 +01:00
test_cgrp2_sock2.c samples: bpf: Refactor test_cgrp2_sock2 program with libbpf 2020-11-26 19:33:35 -08:00
test_cgrp2_sock2.sh samples: bpf: Refactor test_cgrp2_sock2 program with libbpf 2020-11-26 19:33:35 -08:00
test_cgrp2_tc.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
test_cgrp2_tc_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
test_cls_bpf.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
test_current_task_under_cgroup_kern.c samples: bpf: Refactor kprobe tracing programs with libbpf 2020-08-24 20:59:35 -07:00
test_current_task_under_cgroup_user.c samples: bpf: Refactor kprobe tracing programs with libbpf 2020-08-24 20:59:35 -07:00
test_lru_dist.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
test_lwt_bpf.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
test_lwt_bpf.sh samples: bpf: Fix lwt_len_hist reusing previous BPF map 2020-11-26 19:33:36 -08:00
test_map_in_map_kern.c samples/bpf: Fix test_map_in_map on s390 2020-09-19 01:02:55 +02:00
test_map_in_map_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
test_overhead_kprobe_kern.c samples/bpf, selftests/bpf: Use bpf_probe_read_kernel 2020-07-21 13:26:26 -07:00
test_overhead_raw_tp_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
test_overhead_tp_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
test_overhead_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
test_override_return.sh samples: bpf: Fix tracex7 error raised on the missing argument 2021-07-27 11:15:09 -07:00
test_probe_write_user_kern.c samples: bpf: Refactor kprobe tracing programs with libbpf 2020-08-24 20:59:35 -07:00
test_probe_write_user_user.c samples: bpf: Refactor kprobe tracing programs with libbpf 2020-08-24 20:59:35 -07:00
trace_common.h samples, bpf: Refactor kprobe tracing user progs with libbpf 2020-05-19 17:12:53 +02:00
trace_event_kern.c bpf: Remove unused headers 2021-03-25 22:03:46 -07:00
trace_event_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
trace_output_kern.c samples: bpf: Refactor kprobe tracing programs with libbpf 2020-08-24 20:59:35 -07:00
trace_output_user.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
tracex1_kern.c samples/bpf: Fix broken tracex1 due to kprobe argument change 2021-04-19 18:19:49 -07:00
tracex1_user.c samples, bpf: Refactor kprobe tracing user progs with libbpf 2020-05-19 17:12:53 +02:00
tracex2_kern.c samples, bpf: Refactor kprobe, tail call kern progs map definition 2020-05-19 17:13:03 +02:00
tracex2_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
tracex3_kern.c samples: bpf: Fix broken bpf programs due to removed symbol 2020-08-18 17:10:03 -07:00
tracex3_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
tracex4_kern.c samples, bpf: Refactor kprobe, tail call kern progs map definition 2020-05-19 17:13:03 +02:00
tracex4_user.c samples: bpf: Fix a couple of warnings 2021-08-24 14:48:40 -07:00
tracex5_kern.c samples/bpf, selftests/bpf: Use bpf_probe_read_kernel 2020-07-21 13:26:26 -07:00
tracex5_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
tracex6_kern.c samples, bpf: Refactor kprobe, tail call kern progs map definition 2020-05-19 17:13:03 +02:00
tracex6_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
tracex7_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
tracex7_user.c samples: bpf: Fix tracex7 error raised on the missing argument 2021-07-27 11:15:09 -07:00
xdp1_kern.c samples, bpf: Add an explict comment to handle nested vlan tagging. 2021-08-10 11:17:32 +02:00
xdp1_user.c selftests/bpf: Switch to new bpf_object__next_{map,program} APIs 2021-10-06 12:34:02 -07:00
xdp2_kern.c samples, bpf: Add an explict comment to handle nested vlan tagging. 2021-08-10 11:17:32 +02:00
xdp2skb_meta.sh samples/bpf: Fix tc and ip paths in xdp2skb_meta.sh 2018-07-10 09:19:01 +02:00
xdp2skb_meta_kern.c samples: bpf: Remove bpf_load loader completely 2020-11-26 19:33:36 -08:00
xdp_adjust_tail_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
xdp_adjust_tail_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
xdp_fwd_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
xdp_fwd_user.c samples/bpf: Add missing option to xdp_fwd usage 2021-06-16 20:10:18 -07:00
xdp_monitor.bpf.c samples: bpf: Convert xdp_monitor_kern.o to XDP samples helper 2021-08-24 14:48:41 -07:00
xdp_monitor_user.c samples: bpf: Convert xdp_monitor to XDP samples helper 2021-08-24 14:48:41 -07:00
xdp_redirect.bpf.c samples: bpf: Convert xdp_redirect_kern.o to XDP samples helper 2021-08-24 14:48:42 -07:00
xdp_redirect_cpu.bpf.c samples/bpf: Remove unneeded variable 2021-12-09 09:21:45 -08:00
xdp_redirect_cpu_user.c samples/bpf: Fix incorrect use of strlen in xdp_redirect_cpu 2021-11-12 17:23:16 -08:00
xdp_redirect_map.bpf.c samples: bpf: Convert xdp_redirect_map_kern.o to XDP samples helper 2021-08-24 14:48:42 -07:00
xdp_redirect_map_multi.bpf.c samples: bpf: Fix vmlinux.h generation for XDP samples 2021-09-28 17:21:35 -07:00
xdp_redirect_map_multi_user.c samples: bpf: Convert xdp_redirect_map_multi to XDP samples helper 2021-08-24 14:48:42 -07:00
xdp_redirect_map_user.c samples: bpf: Convert xdp_redirect_map to XDP samples helper 2021-08-24 14:48:42 -07:00
xdp_redirect_user.c samples: bpf: Convert xdp_redirect to XDP samples helper 2021-08-24 14:48:42 -07:00
xdp_router_ipv4_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
xdp_router_ipv4_user.c samples: bpf: Convert ARP table network order fields into readable format 2021-09-21 13:27:54 -07:00
xdp_rxq_info_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
xdp_rxq_info_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
xdp_sample.bpf.c samples: bpf: Add BPF support for devmap_xmit tracepoint 2021-08-24 14:48:41 -07:00
xdp_sample.bpf.h samples: bpf: Add BPF support for redirect tracepoint 2021-08-24 14:48:40 -07:00
xdp_sample_pkts_kern.c samples: bpf: Refactor XDP kern program maps with BTF-defined map 2020-10-11 12:14:36 -07:00
xdp_sample_pkts_user.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
xdp_sample_shared.h samples: bpf: Add basic infrastructure for XDP samples 2021-08-24 14:48:40 -07:00
xdp_sample_user.c samples/bpf: Fix summary per-sec stats in xdp_sample_user 2021-11-12 17:23:16 -08:00
xdp_sample_user.h samples: bpf: Fix 'unknown warning group' build warning on Clang 2021-12-06 19:33:44 -08:00
xdp_tx_iptunnel_common.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 206 2019-05-30 11:29:53 -07:00
xdp_tx_iptunnel_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
xdp_tx_iptunnel_user.c bpf: samples: Do not touch RLIMIT_MEMLOCK 2020-12-02 18:32:47 -08:00
xdpsock.h samples/bpf: Sample application for eBPF load and socket creation split 2020-12-03 10:37:59 -08:00
xdpsock_ctrl_proc.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
xdpsock_kern.c samples/bpf: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
xdpsock_user.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00
xsk_fwd.c samples/bpf: Get rid of deprecated libbpf API uses 2021-12-02 15:23:40 -08:00

eBPF sample programs
====================

This directory contains a test stubs, verifier test-suite and examples
for using eBPF. The examples use libbpf from tools/lib/bpf.

Build dependencies
==================

Compiling requires having installed:
 * clang >= version 3.4.0
 * llvm >= version 3.7.1

Note that LLVM's tool 'llc' must support target 'bpf', list version
and supported targets with command: ``llc --version``

Clean and configuration
-----------------------

It can be needed to clean tools, samples or kernel before trying new arch or
after some changes (on demand)::

 make -C tools clean
 make -C samples/bpf clean
 make clean

Configure kernel, defconfig for instance::

 make defconfig

Kernel headers
--------------

There are usually dependencies to header files of the current kernel.
To avoid installing devel kernel headers system wide, as a normal
user, simply call::

 make headers_install

This will creates a local "usr/include" directory in the git/build top
level directory, that the make system automatically pickup first.

Compiling
=========

For building the BPF samples, issue the below command from the kernel
top level directory::

 make M=samples/bpf

It is also possible to call make from this directory.  This will just
hide the invocation of make as above.

Manually compiling LLVM with 'bpf' support
------------------------------------------

Since version 3.7.0, LLVM adds a proper LLVM backend target for the
BPF bytecode architecture.

By default llvm will build all non-experimental backends including bpf.
To generate a smaller llc binary one can use::

 -DLLVM_TARGETS_TO_BUILD="BPF"

We recommend that developers who want the fastest incremental builds
use the Ninja build system, you can find it in your system's package
manager, usually the package is ninja or ninja-build.

Quick sniplet for manually compiling LLVM and clang
(build dependencies are ninja, cmake and gcc-c++)::

 $ git clone https://github.com/llvm/llvm-project.git
 $ mkdir -p llvm-project/llvm/build
 $ cd llvm-project/llvm/build
 $ cmake .. -G "Ninja" -DLLVM_TARGETS_TO_BUILD="BPF;X86" \
            -DLLVM_ENABLE_PROJECTS="clang"    \
            -DCMAKE_BUILD_TYPE=Release        \
            -DLLVM_BUILD_RUNTIME=OFF
 $ ninja

It is also possible to point make to the newly compiled 'llc' or
'clang' command via redefining LLC or CLANG on the make command line::

 make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang

Cross compiling samples
-----------------------
In order to cross-compile, say for arm64 targets, export CROSS_COMPILE and ARCH
environment variables before calling make. But do this before clean,
cofiguration and header install steps described above. This will direct make to
build samples for the cross target::

 export ARCH=arm64
 export CROSS_COMPILE="aarch64-linux-gnu-"

Headers can be also installed on RFS of target board if need to keep them in
sync (not necessarily and it creates a local "usr/include" directory also)::

 make INSTALL_HDR_PATH=~/some_sysroot/usr headers_install

Pointing LLC and CLANG is not necessarily if it's installed on HOST and have
in its targets appropriate arm64 arch (usually it has several arches).
Build samples::

 make M=samples/bpf

Or build samples with SYSROOT if some header or library is absent in toolchain,
say libelf, providing address to file system containing headers and libs,
can be RFS of target board::

 make M=samples/bpf SYSROOT=~/some_sysroot