Subject: Re: [PATCH bpf-next v3 00/10] BTF: BPF Type Format

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Mon, 16 Apr 2018 17:22:00 -0300

Em Mon, Apr 16, 2018 at 12:33:17PM -0700, Martin KaFai Lau escreveu:
> This patch introduces BPF Type Format (BTF).
> 
> BTF (BPF Type Format) is the meta data format which describes
> the data types of BPF program/map.  Hence, it basically focus
> on the C programming language which the modern BPF is primary
> using.  The first use case is to provide a generic pretty print
> capability for a BPF map.
> 
> A modified pahole (Cc: Arnaldo) that can convert dwarf to BTF is here:
> https://github.com/iamkafai/pahole/tree/btf

Thanks for CCing me, no changes since when you posted the pahole
patches, I gave it a quick look, seems sane, will try to merge and push
a new pahole version out so that distros can pick it, at least fedora
will 8-)

- Arnaldo
 
> Please see individual patch for details.
> 
> v3:
> - Rebase to bpf-next
> - Fix sparse warning (by adding static)
> - Add BTF header logging: btf_verifier_log_hdr()
> - Fix the alignment test on btf->type_off
> - Add tests for the BTF header
> - Lower the max BTF size to 16MB.  It should be enough
>   for some time.  We could raise it later if it would
>   be needed.
> 
> v2:
> - Use kvfree where needed in patch 1 and 2
> - Also consider BTF_INT_OFFSET() in the btf_int_check_meta()
>   in patch 1
> - Fix an incorrect goto target in map_create() during
>   the btf-error-path in patch 7
> - re-org some local vars to keep the rev xmas tree in btf.c
> 
> Martin KaFai Lau (10):
>   bpf: btf: Introduce BPF Type Format (BTF)
>   bpf: btf: Validate type reference
>   bpf: btf: Check members of struct/union
>   bpf: btf: Add pretty print capability for data with BTF type info
>   bpf: btf: Add BPF_BTF_LOAD command
>   bpf: btf: Add BPF_OBJ_GET_INFO_BY_FD support to BTF fd
>   bpf: btf: Add pretty print support to the basic arraymap
>   bpf: btf: Sync bpf.h and btf.h to tools/
>   bpf: btf: Add BTF support to libbpf
>   bpf: btf: Add BTF tests
> 
>  include/linux/bpf.h                          |   20 +-
>  include/linux/btf.h                          |   48 +
>  include/uapi/linux/bpf.h                     |   12 +
>  include/uapi/linux/btf.h                     |  132 ++
>  kernel/bpf/Makefile                          |    1 +
>  kernel/bpf/arraymap.c                        |   50 +
>  kernel/bpf/btf.c                             | 2093 ++++++++++++++++++++++++++
>  kernel/bpf/inode.c                           |  146 +-
>  kernel/bpf/syscall.c                         |   51 +-
>  tools/include/uapi/linux/bpf.h               |   13 +
>  tools/include/uapi/linux/btf.h               |  132 ++
>  tools/lib/bpf/Build                          |    2 +-
>  tools/lib/bpf/bpf.c                          |   92 +-
>  tools/lib/bpf/bpf.h                          |   16 +
>  tools/lib/bpf/btf.c                          |  377 +++++
>  tools/lib/bpf/btf.h                          |   22 +
>  tools/lib/bpf/libbpf.c                       |  148 +-
>  tools/lib/bpf/libbpf.h                       |    3 +
>  tools/testing/selftests/bpf/Makefile         |   26 +-
>  tools/testing/selftests/bpf/test_btf.c       | 1669 ++++++++++++++++++++
>  tools/testing/selftests/bpf/test_btf_haskv.c |   48 +
>  tools/testing/selftests/bpf/test_btf_nokv.c  |   43 +
>  22 files changed, 5103 insertions(+), 41 deletions(-)
>  create mode 100644 include/linux/btf.h
>  create mode 100644 include/uapi/linux/btf.h
>  create mode 100644 kernel/bpf/btf.c
>  create mode 100644 tools/include/uapi/linux/btf.h
>  create mode 100644 tools/lib/bpf/btf.c
>  create mode 100644 tools/lib/bpf/btf.h
>  create mode 100644 tools/testing/selftests/bpf/test_btf.c
>  create mode 100644 tools/testing/selftests/bpf/test_btf_haskv.c
>  create mode 100644 tools/testing/selftests/bpf/test_btf_nokv.c
> 
> -- 
> 2.9.5