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From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>, Yonghong Song <yhs@fb.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>,
	bpf@vger.kernel.org, Heiko Carstens <heiko.carstens@de.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH v2 bpf-next 0/6] Add BTF_KIND_FLOAT support
Date: Fri, 19 Feb 2021 03:25:37 +0100
Message-ID: <20210219022543.20893-1-iii@linux.ibm.com> (raw)

Some BPF programs compiled on s390 fail to load, because s390
arch-specific linux headers contain float and double types.
    
Introduce support for such types by representing them using the new
BTF_KIND_FLOAT. This series deals with libbpf, bpftool, in-kernel BTF
parser as well as selftests and documentation.

There are also pahole and LLVM parts:

* https://github.com/iii-i/dwarves/commit/btf-kind-float-v2
* https://reviews.llvm.org/D83289

but they should go in after the libbpf part is integrated.

---

v0: https://lore.kernel.org/bpf/20210210030317.78820-1-iii@linux.ibm.com/
v0 -> v1: Per Andrii's suggestion, remove the unnecessary trailing u32.

v1: https://lore.kernel.org/bpf/20210216011216.3168-1-iii@linux.ibm.com/
v1 -> v2: John noticed that sanitization corrupts BTF, because new and
          old sizes don't match. Per Yonghong's suggestion, use a
          modifier type (which has the same size as the float type) as
          a replacement.
          Per Yonghong's suggestion, add size and alignment checks to
          the kernel BTF parser.

Based on Alexei's feedback [1] I'm proceeding with the BTF_KIND_FLOAT
approach.

[1] https://lore.kernel.org/bpf/CAADnVQKWPODWZ2RSJ5FJhfYpxkuV0cvSAL1O+FSr9oP1ercoBg@mail.gmail.com/

Ilya Leoshkevich (6):
  bpf: Add BTF_KIND_FLOAT to uapi
  libbpf: Add BTF_KIND_FLOAT support
  tools/bpftool: Add BTF_KIND_FLOAT support
  bpf: Add BTF_KIND_FLOAT support
  selftest/bpf: Add BTF_KIND_FLOAT tests
  bpf: Document BTF_KIND_FLOAT in btf.rst

 Documentation/bpf/btf.rst                    |  17 ++-
 include/uapi/linux/btf.h                     |   5 +-
 kernel/bpf/btf.c                             |  76 +++++++++++-
 tools/bpf/bpftool/btf.c                      |   8 ++
 tools/bpf/bpftool/btf_dumper.c               |   1 +
 tools/include/uapi/linux/btf.h               |   5 +-
 tools/lib/bpf/btf.c                          |  44 +++++++
 tools/lib/bpf/btf.h                          |   8 ++
 tools/lib/bpf/btf_dump.c                     |   4 +
 tools/lib/bpf/libbpf.c                       |  45 ++++++-
 tools/lib/bpf/libbpf.map                     |   5 +
 tools/lib/bpf/libbpf_internal.h              |   2 +
 tools/testing/selftests/bpf/btf_helpers.c    |   4 +
 tools/testing/selftests/bpf/prog_tests/btf.c | 122 +++++++++++++++++++
 tools/testing/selftests/bpf/test_btf.h       |   3 +
 15 files changed, 340 insertions(+), 9 deletions(-)

-- 
2.29.2


             reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-19  2:25 Ilya Leoshkevich [this message]
2021-02-19  2:25 ` [PATCH v2 bpf-next 1/6] bpf: Add BTF_KIND_FLOAT to uapi Ilya Leoshkevich
2021-02-19  2:25 ` [PATCH v2 bpf-next 2/6] libbpf: Add BTF_KIND_FLOAT support Ilya Leoshkevich
2021-02-19  4:22   ` Yonghong Song
2021-02-19 23:01     ` Ilya Leoshkevich
2021-02-19 23:35       ` Yonghong Song
2021-02-19 23:43         ` Ilya Leoshkevich
2021-02-19  2:25 ` [PATCH v2 bpf-next 3/6] tools/bpftool: " Ilya Leoshkevich
2021-02-19  2:25 ` [PATCH v2 bpf-next 4/6] bpf: " Ilya Leoshkevich
2021-02-19  4:04   ` kernel test robot
2021-02-19  4:13   ` kernel test robot
2021-02-19  2:25 ` [PATCH v2 bpf-next 5/6] selftest/bpf: Add BTF_KIND_FLOAT tests Ilya Leoshkevich
2021-02-19  5:38   ` Yonghong Song
2021-02-19  5:44   ` Yonghong Song
2021-02-19  2:25 ` [PATCH v2 bpf-next 6/6] bpf: Document BTF_KIND_FLOAT in btf.rst Ilya Leoshkevich
2021-02-19  5:41   ` Yonghong Song
2021-02-19 13:00     ` Ilya Leoshkevich
2021-02-19 15:26       ` Yonghong Song

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