bpf: Add 64bit enum value support

Currently, btf only supports upto 32bit enum value with BTF_KIND_ENUM.
But in kernel, some enum has 64bit values, e.g., in uapi bpf.h, we have
  enum {
        BPF_F_INDEX_MASK                = 0xffffffffULL,
        BPF_F_CURRENT_CPU               = BPF_F_INDEX_MASK,
        BPF_F_CTXLEN_MASK               = (0xfffffULL << 32),
  };
With BTF_KIND_ENUM, the value for BPF_F_CTXLEN_MASK will be encoded
as 0 which is incorrect.

To solve this problem, BTF_KIND_ENUM64 is proposed in this patch set
to support enum 64bit values. Also, since sometimes there is a need
to generate C code from btf, e.g., vmlinux.h, btf kflag support
is also added for BTF_KIND_ENUM and BTF_KIND_ENUM64, which will
permit proper value printout, signed or unsigned.

In the rest of this patch set, Patch #1 added kernel support,
Patches #2 - #4 for libbpf, Patch #5 for bpftool. Patches #6 - #11
are for various selftests, and Patch #12 added BTF_KIND_ENUM64
in btf documentation.

Yonghong Song (12):
  bpf: Add btf enum64 support
  libbpf: Permit 64bit relocation value
  libbpf: Fix an error in 64bit relocation value computation
  libbpf: Add btf enum64 support
  bpftool: Add btf enum64 support
  selftests/bpf: Fix selftests failure
  selftests/bpf: Test new libbpf enum32/enum64 API functions
  selftests/bpf: Add BTF_KIND_ENUM64 unit tests
  selftests/bpf: Test BTF_KIND_ENUM64 for deduplication
  selftests/bpf: add a test for enum64 value relocation
  selftests/bpf: Clarify llvm dependency with possible selftest failures
  docs/bpf: Update documentation for BTF_KIND_ENUM64 support

 Documentation/bpf/btf.rst                     |  34 ++-
 include/linux/btf.h                           |  18 +-
 include/uapi/linux/btf.h                      |  17 +-
 kernel/bpf/btf.c                              | 132 +++++++++-
 tools/bpf/bpftool/btf.c                       |  47 +++-
 tools/bpf/bpftool/btf_dumper.c                |  32 +++
 tools/bpf/bpftool/gen.c                       |   1 +
 tools/include/uapi/linux/btf.h                |  17 +-
 tools/lib/bpf/btf.c                           | 226 +++++++++++++++++-
 tools/lib/bpf/btf.h                           |  21 ++
 tools/lib/bpf/btf_dump.c                      |  94 ++++++--
 tools/lib/bpf/libbpf.c                        |  64 ++++-
 tools/lib/bpf/libbpf.map                      |   4 +
 tools/lib/bpf/libbpf_internal.h               |   2 +
 tools/lib/bpf/linker.c                        |   2 +
 tools/lib/bpf/relo_core.c                     | 119 +++++----
 tools/lib/bpf/relo_core.h                     |   4 +-
 tools/testing/selftests/bpf/README.rst        |  18 ++
 tools/testing/selftests/bpf/btf_helpers.c     |  21 +-
 tools/testing/selftests/bpf/prog_tests/btf.c  | 128 ++++++++--
 .../selftests/bpf/prog_tests/btf_dump.c       |  10 +-
 .../selftests/bpf/prog_tests/btf_write.c      | 120 +++++++---
 .../selftests/bpf/prog_tests/core_reloc.c     |  43 ++++
 .../bpf/progs/btf__core_reloc_enum64val.c     |   3 +
 .../progs/btf__core_reloc_enum64val___diff.c  |   3 +
 .../btf__core_reloc_enum64val___err_missing.c |   3 +
 ...btf__core_reloc_enum64val___val3_missing.c |   3 +
 .../bpf/progs/btf_dump_test_case_syntax.c     |   2 +-
 .../selftests/bpf/progs/core_reloc_types.h    |  47 ++++
 .../bpf/progs/test_core_reloc_enum64val.c     |  53 ++++
 tools/testing/selftests/bpf/test_btf.h        |   1 +
 31 files changed, 1126 insertions(+), 163 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_enum64val.c
 create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_enum64val___diff.c
 create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_enum64val___err_missing.c
 create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_enum64val___val3_missing.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_core_reloc_enum64val.c

-- 
2.30.2