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 v7 bpf-next 00/10] Add BTF_KIND_FLOAT support
Date: Fri, 26 Feb 2021 21:22:46 +0100 [thread overview]
Message-ID: <20210226202256.116518-1-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 v4: More fixes for the Yonghong's findings: fix the outdated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).
v4: https://lore.kernel.org/bpf/20210222214917.83629-1-iii@linux.ibm.com/
v4 -> v5: Fixes for the Andrii's findings: Use BTF_KIND_STRUCT instead
of BTF_KIND_TYPEDEF for sanitization; check byte_sz in
libbpf; move btf__add_float; remove relo support; add a dedup
test (new commit, #7).
v5: https://lore.kernel.org/bpf/20210223231459.99664-1-iii@linux.ibm.com/
v5 -> v6: Fixes for further findings by Andrii: split whitespace issue
fix into a separate patch; add 12-byte float to "float test #1,
well-formed".
v6: https://lore.kernel.org/bpf/20210224234535.106970-1-iii@linux.ibm.com/
v6 -> v7: John suggested to add a comment explaining why sanitization
does not preserve the type name, as well as what effect it has
on running the code on the older kernels.
Yonghong has asked to add a comment explaining why we are not
checking the alignment very precisely in the kernel.
John suggested to add a bpf_core_field_size test (commit #9).
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 (10):
bpf: Add BTF_KIND_FLOAT to uapi
libbpf: Fix whitespace in btf_add_composite() comment
libbpf: Add BTF_KIND_FLOAT support
tools/bpftool: Add BTF_KIND_FLOAT support
selftests/bpf: Use the 25th bit in the "invalid BTF_INFO" test
bpf: Add BTF_KIND_FLOAT support
selftest/bpf: Add BTF_KIND_FLOAT tests
selftests/bpf: Add BTF_KIND_FLOAT to the existing deduplication tests
selftests/bpf: Add BTF_KIND_FLOAT to test_core_reloc_size
bpf: Document BTF_KIND_FLOAT in btf.rst
Documentation/bpf/btf.rst | 17 +-
include/uapi/linux/btf.h | 5 +-
kernel/bpf/btf.c | 83 ++++++++-
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 | 51 ++++-
tools/lib/bpf/btf.h | 6 +
tools/lib/bpf/btf_dump.c | 4 +
tools/lib/bpf/libbpf.c | 29 ++-
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 | 176 ++++++++++++++++--
.../selftests/bpf/prog_tests/core_reloc.c | 1 +
.../selftests/bpf/progs/core_reloc_types.h | 5 +
.../bpf/progs/test_core_reloc_size.c | 3 +
tools/testing/selftests/bpf/test_btf.h | 3 +
18 files changed, 385 insertions(+), 23 deletions(-)
--
2.29.2
next reply other threads:[~2021-02-26 20:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 20:22 Ilya Leoshkevich [this message]
2021-02-26 20:22 ` [PATCH v7 bpf-next 01/10] bpf: Add BTF_KIND_FLOAT to uapi Ilya Leoshkevich
2021-02-26 20:22 ` [PATCH v7 bpf-next 02/10] libbpf: Fix whitespace in btf_add_composite() comment Ilya Leoshkevich
2021-02-26 23:32 ` Yonghong Song
2021-02-26 20:22 ` [PATCH v7 bpf-next 03/10] libbpf: Add BTF_KIND_FLOAT support Ilya Leoshkevich
2021-02-26 20:22 ` [PATCH v7 bpf-next 04/10] tools/bpftool: " Ilya Leoshkevich
2021-02-26 20:22 ` [PATCH v7 bpf-next 05/10] selftests/bpf: Use the 25th bit in the "invalid BTF_INFO" test Ilya Leoshkevich
2021-02-26 20:22 ` [PATCH v7 bpf-next 06/10] bpf: Add BTF_KIND_FLOAT support Ilya Leoshkevich
2021-02-26 23:33 ` Yonghong Song
2021-02-26 20:22 ` [PATCH v7 bpf-next 07/10] selftest/bpf: Add BTF_KIND_FLOAT tests Ilya Leoshkevich
2021-02-26 20:22 ` [PATCH v7 bpf-next 08/10] selftests/bpf: Add BTF_KIND_FLOAT to the existing deduplication tests Ilya Leoshkevich
2021-02-26 20:22 ` [PATCH v7 bpf-next 09/10] selftests/bpf: Add BTF_KIND_FLOAT to test_core_reloc_size Ilya Leoshkevich
2021-02-26 20:22 ` [PATCH v7 bpf-next 10/10] bpf: Document BTF_KIND_FLOAT in btf.rst Ilya Leoshkevich
2021-03-05 2:36 ` [PATCH v7 bpf-next 00/10] Add BTF_KIND_FLOAT support Alexei Starovoitov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210226202256.116518-1-iii@linux.ibm.com \
--to=iii@linux.ibm.com \
--cc=acme@redhat.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=gor@linux.ibm.com \
--cc=heiko.carstens@de.ibm.com \
--cc=john.fastabend@gmail.com \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).