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>,
John Fastabend <john.fastabend@gmail.com>
Cc: 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 v4 bpf-next 0/7] Add BTF_KIND_FLOAT support
Date: Mon, 22 Feb 2021 22:49:10 +0100 [thread overview]
Message-ID: <20210222214917.83629-1-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.
v2: https://lore.kernel.org/bpf/20210219022543.20893-1-iii@linux.ibm.com/
v2 -> v3: Based on Yonghong's suggestions: Use BTF_KIND_CONST instead of
BTF_KIND_TYPEDEF and make sure that the C code generated from
the sanitized BTF is well-formed; fix size calculation in
tests and use NAME_TBD everywhere; limit allowed sizes to 2,
4, 8, 12 and 16 (this should also fix m68k and nds32le
builds).
v3: https://lore.kernel.org/bpf/20210220034959.27006-1-iii@linux.ibm.com/
v3 -> v4: More fixes for the Yonghong's findings: fix the outdated
comment in bpf_object__sanitize_btf() and add the error
handling there (I've decided to check uint_id and uchar_id
too in order to simplify debugging); add bpftool output
example; use div64_u64_rem() instead of % in order to fix the
linker error.
Also fix the "invalid BTF_INFO" test (new commit, #4).
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 (7):
bpf: Add BTF_KIND_FLOAT to uapi
libbpf: Add BTF_KIND_FLOAT support
tools/bpftool: Add BTF_KIND_FLOAT support
selftests/bpf: Use 25th bit in "invalid BTF_INFO" test
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 | 79 ++++++++++-
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 | 84 +++++++++++-
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 | 131 ++++++++++++++++++-
tools/testing/selftests/bpf/test_btf.h | 3 +
15 files changed, 386 insertions(+), 14 deletions(-)
--
2.29.2
next reply other threads:[~2021-02-22 21:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-22 21:49 Ilya Leoshkevich [this message]
2021-02-22 21:49 ` [PATCH v4 bpf-next 1/7] bpf: Add BTF_KIND_FLOAT to uapi Ilya Leoshkevich
2021-02-22 21:49 ` [PATCH v4 bpf-next 2/7] libbpf: Add BTF_KIND_FLOAT support Ilya Leoshkevich
2021-02-23 7:03 ` Andrii Nakryiko
2021-02-23 7:08 ` Andrii Nakryiko
2021-02-23 20:14 ` Ilya Leoshkevich
2021-02-22 21:49 ` [PATCH v4 bpf-next 3/7] tools/bpftool: " Ilya Leoshkevich
2021-02-22 21:49 ` [PATCH v4 bpf-next 4/7] selftests/bpf: Use 25th bit in "invalid BTF_INFO" test Ilya Leoshkevich
2021-02-22 21:49 ` [PATCH v4 bpf-next 5/7] bpf: Add BTF_KIND_FLOAT support Ilya Leoshkevich
2021-02-22 21:49 ` [PATCH v4 bpf-next 6/7] selftest/bpf: Add BTF_KIND_FLOAT tests Ilya Leoshkevich
2021-02-23 7:11 ` Andrii Nakryiko
2021-02-23 20:16 ` Ilya Leoshkevich
2021-02-23 21:35 ` Andrii Nakryiko
2021-02-22 21:49 ` [PATCH v4 bpf-next 7/7] bpf: Document BTF_KIND_FLOAT in btf.rst Ilya Leoshkevich
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