From: Hao Luo <haoluo@google.com>
To: netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Cc: Shuah Khan <shuah@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andriin@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
Quentin Monnet <quentin@isovalent.com>,
Hao Luo <haoluo@google.com>, Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>, Andrey Ignatov <rdna@fb.com>,
Jakub Sitnicki <jakub@cloudflare.com>
Subject: [PATCH bpf-next v2 0/6] bpf: BTF support for ksyms
Date: Thu, 3 Sep 2020 15:33:26 -0700 [thread overview]
Message-ID: <20200903223332.881541-1-haoluo@google.com> (raw)
v1 -> v2:
- Move check_pseudo_btf_id from check_ld_imm() to
replace_map_fd_with_map_ptr() and rename the latter.
- Add bpf_this_cpu_ptr().
- Use bpf_core_types_are_compat() in libbpf.c for checking type
compatibility.
- Rewrite typed ksym extern type in BTF with int to save space.
- Minor revision of bpf_per_cpu_ptr()'s comments.
- Avoid using long in tests that use skeleton.
- Refactored test_ksyms.c by moving kallsyms_find() to trace_helpers.c
- Fold the patches that sync include/linux/uapi and
tools/include/linux/uapi.
rfc -> v1:
- Encode VAR's btf_id for PSEUDO_BTF_ID.
- More checks in verifier. Checking the btf_id passed as
PSEUDO_BTF_ID is valid VAR, its name and type.
- Checks in libbpf on type compatibility of ksyms.
- Add bpf_per_cpu_ptr() to access kernel percpu vars. Introduced
new ARG and RET types for this helper.
This patch series extends the previously added __ksym externs with
btf support.
Right now the __ksym externs are treated as pure 64-bit scalar value.
Libbpf replaces ld_imm64 insn of __ksym by its kernel address at load
time. This patch series extend those externs with their btf info. Note
that btf support for __ksym must come with the kernel btf that has
VARs encoded to work properly. The corresponding chagnes in pahole
is available at [1] (with a fix at [2] for gcc 4.9+).
The first 3 patches in this series add support for general kernel
global variables, which include verifier checking (01/06), libpf
support (02/06) and selftests for getting typed ksym extern's kernel
address (03/06).
The next 3 patches extends that capability further by introducing
helpers bpf_per_cpu_ptr() and bpf_this_cpu_ptr(), which allows accessing
kernel percpu variables correctly (04/06 and 05/06).
The tests of this feature were performed against pahole that is extended
with [1] and [2]. For kernel BTF that does not have VARs encoded, the
selftests will be skipped.
[1] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=f3d9054ba8ff1df0fc44e507e3a01c0964cabd42
[2] https://www.spinics.net/lists/dwarves/msg00451.html
Hao Luo (6):
bpf: Introduce pseudo_btf_id
bpf/libbpf: BTF support for typed ksyms
bpf/selftests: ksyms_btf to test typed ksyms
bpf: Introduce bpf_per_cpu_ptr()
bpf: Introduce bpf_this_cpu_ptr()
bpf/selftests: Test for bpf_per_cpu_ptr() and bpf_this_cpu_ptr()
include/linux/bpf.h | 4 +
include/linux/bpf_verifier.h | 4 +
include/linux/btf.h | 26 +++
include/uapi/linux/bpf.h | 69 ++++++-
kernel/bpf/btf.c | 25 ---
kernel/bpf/verifier.c | 176 +++++++++++++++++-
kernel/trace/bpf_trace.c | 32 ++++
tools/include/uapi/linux/bpf.h | 69 ++++++-
tools/lib/bpf/libbpf.c | 116 ++++++++++--
.../testing/selftests/bpf/prog_tests/ksyms.c | 31 +--
.../selftests/bpf/prog_tests/ksyms_btf.c | 73 ++++++++
.../selftests/bpf/progs/test_ksyms_btf.c | 49 +++++
tools/testing/selftests/bpf/trace_helpers.c | 26 +++
tools/testing/selftests/bpf/trace_helpers.h | 4 +
14 files changed, 615 insertions(+), 89 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/ksyms_btf.c
create mode 100644 tools/testing/selftests/bpf/progs/test_ksyms_btf.c
--
2.28.0.526.ge36021eeef-goog
next reply other threads:[~2020-09-03 22:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 22:33 Hao Luo [this message]
2020-09-03 22:33 ` [PATCH bpf-next v2 1/6] bpf: Introduce pseudo_btf_id Hao Luo
2020-09-04 19:05 ` Andrii Nakryiko
2020-09-14 4:55 ` Hao Luo
2020-09-03 22:33 ` [PATCH bpf-next v2 2/6] bpf/libbpf: BTF support for typed ksyms Hao Luo
2020-09-04 19:34 ` Andrii Nakryiko
2020-09-14 4:56 ` Hao Luo
2020-09-03 22:33 ` [PATCH bpf-next v2 3/6] bpf/selftests: ksyms_btf to test " Hao Luo
2020-09-04 19:49 ` Andrii Nakryiko
2020-09-14 4:58 ` Hao Luo
2020-09-14 22:06 ` Andrii Nakryiko
2020-09-03 22:33 ` [PATCH bpf-next v2 4/6] bpf: Introduce bpf_per_cpu_ptr() Hao Luo
2020-09-04 20:04 ` Andrii Nakryiko
2020-09-14 5:01 ` Hao Luo
2020-09-14 18:09 ` Andrii Nakryiko
2020-09-03 22:33 ` [PATCH bpf-next v2 5/6] bpf: Introduce bpf_this_cpu_ptr() Hao Luo
2020-09-04 20:09 ` Andrii Nakryiko
2020-09-14 5:04 ` Hao Luo
2020-09-03 22:33 ` [PATCH bpf-next v2 6/6] bpf/selftests: Test for bpf_per_cpu_ptr() and bpf_this_cpu_ptr() Hao Luo
2020-09-04 20:15 ` Andrii Nakryiko
2020-09-14 16:59 ` Hao Luo
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