linux/tools/bpf
Niklas Söderlund f655c088e7 bpftool: Restore support for BPF offload-enabled feature probing
Commit 1a56c18e6c ("bpftool: Stop supporting BPF offload-enabled
feature probing") removed the support to probe for BPF offload features.
This is still something that is useful for NFP NIC that can support
offloading of BPF programs.

The reason for the dropped support was that libbpf starting with v1.0
would drop support for passing the ifindex to the BPF prog/map/helper
feature probing APIs. In order to keep this useful feature for NFP
restore the functionality by moving it directly into bpftool.

The code restored is a simplified version of the code that existed in
libbpf which supposed passing the ifindex. The simplification is that it
only targets the cases where ifindex is given and call into libbpf for
the cases where it's not.

Before restoring support for probing offload features:

  # bpftool feature probe dev ens4np0
  Scanning system call availability...
  bpf() syscall is available

  Scanning eBPF program types...

  Scanning eBPF map types...

  Scanning eBPF helper functions...
  eBPF helpers supported for program type sched_cls:
  eBPF helpers supported for program type xdp:

  Scanning miscellaneous eBPF features...
  Large program size limit is NOT available
  Bounded loop support is NOT available
  ISA extension v2 is NOT available
  ISA extension v3 is NOT available

With support for probing offload features restored:

  # bpftool feature probe dev ens4np0
  Scanning system call availability...
  bpf() syscall is available

  Scanning eBPF program types...
  eBPF program_type sched_cls is available
  eBPF program_type xdp is available

  Scanning eBPF map types...
  eBPF map_type hash is available
  eBPF map_type array is available

  Scanning eBPF helper functions...
  eBPF helpers supported for program type sched_cls:
  	- bpf_map_lookup_elem
  	- bpf_get_prandom_u32
  	- bpf_perf_event_output
  eBPF helpers supported for program type xdp:
  	- bpf_map_lookup_elem
  	- bpf_get_prandom_u32
  	- bpf_perf_event_output
  	- bpf_xdp_adjust_head
  	- bpf_xdp_adjust_tail

  Scanning miscellaneous eBPF features...
  Large program size limit is NOT available
  Bounded loop support is NOT available
  ISA extension v2 is NOT available
  ISA extension v3 is NOT available

Signed-off-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220310121846.921256-1-niklas.soderlund@corigine.com
2022-03-10 16:09:47 +01:00
..
bpftool bpftool: Restore support for BPF offload-enabled feature probing 2022-03-10 16:09:47 +01:00
resolve_btfids Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-03 17:36:16 -08:00
runqslower tools/bpf: Rename 'struct event' to avoid naming conflict 2022-01-15 12:21:25 +11:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
bpf_asm.c docs: networking: convert filter.txt to ReST 2020-04-28 14:39:46 -07:00
bpf_dbg.c bpf: Simplify the calculation of variables 2021-03-04 19:24:53 -08:00
bpf_exp.l bpf: fix cbpf parser bug for octal numbers 2018-06-03 07:46:55 -07:00
bpf_exp.y tools, bpf_asm: Exit non-zero on errors 2021-02-26 22:53:50 +01:00
bpf_jit_disasm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 232 2019-06-19 17:09:06 +02:00
Makefile tools: bpf: Fix error in 'make -C tools/ bpf_install' 2021-07-07 14:06:38 -07:00