[RFC PATCH bpf-next 0/8] BTF-defined BPF map definitions

[Andrii Nakryiko <andriin@fb.com>]

This patch set implements initial version (as discussed at LSF/MM2019
conference) of a new way to specify BPF maps, relying on BTF type information,
which allows for easy extensibility, preserving forward and backward
compatibility. See details and examples in description for patch #6.

Patch #1 centralizes commonly used min/max macro in libbpf_internal.h.
Patch #2 extracts .BTF and .BTF.ext loading loging from elf_collect().
Patch #3 refactors map initialization logic into user-provided maps and global
data maps, in preparation to adding another way (BTF-defined maps).
Patch #4 adds support for map definitions in multiple ELF sections and
deprecates bpf_object__find_map_by_offset() API which doesn't appear to be
used anymore and makes assumption that all map definitions reside in single
ELF section.
Patch #5 splits BTF intialization from sanitization/loading into kernel to
preserve original BTF at the time of map initialization.
Patch #6 adds support for BTF-defined maps.
Patch #7 adds new test for BTF-defined map definition.
Patch #8 converts test BPF map definitions to use BTF way.

Andrii Nakryiko (8):
  libbpf: add common min/max macro to libbpf_internal.h
  libbpf: extract BTF loading and simplify ELF parsing logic
  libbpf: refactor map initialization
  libbpf: identify maps by section index in addition to offset
  libbpf: split initialization and loading of BTF
  libbpf: allow specifying map definitions using BTF
  selftests/bpf: add test for BTF-defined maps
  selftests/bpf: switch tests to BTF-defined map definitions

 tools/lib/bpf/bpf.c                           |   7 +-
 tools/lib/bpf/bpf_prog_linfo.c                |   5 +-
 tools/lib/bpf/btf.c                           |   3 -
 tools/lib/bpf/btf.h                           |   1 +
 tools/lib/bpf/btf_dump.c                      |   3 -
 tools/lib/bpf/libbpf.c                        | 762 +++++++++++++-----
 tools/lib/bpf/libbpf_internal.h               |   7 +
 tools/testing/selftests/bpf/progs/bpf_flow.c  |  18 +-
 .../selftests/bpf/progs/get_cgroup_id_kern.c  |  18 +-
 .../testing/selftests/bpf/progs/netcnt_prog.c |  22 +-
 .../selftests/bpf/progs/sample_map_ret0.c     |  18 +-
 .../selftests/bpf/progs/socket_cookie_prog.c  |   9 +-
 .../bpf/progs/sockmap_verdict_prog.c          |  36 +-
 .../selftests/bpf/progs/test_btf_newkv.c      |  73 ++
 .../bpf/progs/test_get_stack_rawtp.c          |  27 +-
 .../selftests/bpf/progs/test_global_data.c    |  27 +-
 tools/testing/selftests/bpf/progs/test_l4lb.c |  45 +-
 .../selftests/bpf/progs/test_l4lb_noinline.c  |  45 +-
 .../selftests/bpf/progs/test_map_in_map.c     |  20 +-
 .../selftests/bpf/progs/test_map_lock.c       |  22 +-
 .../testing/selftests/bpf/progs/test_obj_id.c |   9 +-
 .../bpf/progs/test_select_reuseport_kern.c    |  45 +-
 .../bpf/progs/test_send_signal_kern.c         |  22 +-
 .../bpf/progs/test_skb_cgroup_id_kern.c       |   9 +-
 .../bpf/progs/test_sock_fields_kern.c         |  60 +-
 .../selftests/bpf/progs/test_spin_lock.c      |  33 +-
 .../bpf/progs/test_stacktrace_build_id.c      |  44 +-
 .../selftests/bpf/progs/test_stacktrace_map.c |  40 +-
 .../testing/selftests/bpf/progs/test_tc_edt.c |   9 +-
 .../bpf/progs/test_tcp_check_syncookie_kern.c |   9 +-
 .../selftests/bpf/progs/test_tcp_estats.c     |   9 +-
 .../selftests/bpf/progs/test_tcpbpf_kern.c    |  18 +-
 .../selftests/bpf/progs/test_tcpnotify_kern.c |  18 +-
 tools/testing/selftests/bpf/progs/test_xdp.c  |  18 +-
 .../selftests/bpf/progs/test_xdp_noinline.c   |  60 +-
 tools/testing/selftests/bpf/test_btf.c        |  10 +-
 .../selftests/bpf/test_queue_stack_map.h      |  20 +-
 .../testing/selftests/bpf/test_sockmap_kern.h |  72 +-
 38 files changed, 1182 insertions(+), 491 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/test_btf_newkv.c

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2.17.1