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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 v1 0/8] bpf: BTF support for ksyms
Date: Wed, 19 Aug 2020 15:40:22 -0700	[thread overview]
Message-ID: <20200819224030.1615203-1-haoluo@google.com> (raw)

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].

The first 5 patches in this series add support for general kernel
global variables, which includes verifier checking (01/08), libbpf
type checking (03/08) and btf_id resolving (04/08).

The last 3 patches extends that capability further by introducing a
helper bpf_per_cpu_ptr(), which allows accessing kernel percpu vars
correctly (06/08).

The tests of this feature were performed against the extended pahole.
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

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.

Hao Luo (8):
  bpf: Introduce pseudo_btf_id
  bpf: Propagate BPF_PSEUDO_BTF_ID to uapi headers in /tools
  bpf: Introduce help function to validate ksym's type.
  bpf/libbpf: BTF support for typed ksyms
  bpf/selftests: ksyms_btf to test typed ksyms
  bpf: Introduce bpf_per_cpu_ptr()
  bpf: Propagate bpf_per_cpu_ptr() to /tools
  bpf/selftests: Test for bpf_per_cpu_ptr()

 include/linux/bpf.h                           |   3 +
 include/linux/btf.h                           |  26 +++
 include/uapi/linux/bpf.h                      |  52 +++++-
 kernel/bpf/btf.c                              |  25 ---
 kernel/bpf/verifier.c                         | 128 ++++++++++++-
 kernel/trace/bpf_trace.c                      |  18 ++
 tools/include/uapi/linux/bpf.h                |  53 +++++-
 tools/lib/bpf/btf.c                           | 171 ++++++++++++++++++
 tools/lib/bpf/btf.h                           |   2 +
 tools/lib/bpf/libbpf.c                        | 130 +++++++++++--
 .../selftests/bpf/prog_tests/ksyms_btf.c      |  81 +++++++++
 .../selftests/bpf/progs/test_ksyms_btf.c      |  36 ++++
 12 files changed, 665 insertions(+), 60 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

-- 
2.28.0.220.ged08abb693-goog


             reply	other threads:[~2020-08-19 22:40 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-19 22:40 Hao Luo [this message]
2020-08-19 22:40 ` [PATCH bpf-next v1 1/8] bpf: Introduce pseudo_btf_id Hao Luo
2020-08-20 15:22   ` Yonghong Song
2020-08-20 17:04     ` Hao Luo
2020-08-25  0:05     ` Hao Luo
2020-08-25  0:43       ` Yonghong Song
2020-08-20 16:43   ` Yonghong Song
2020-08-20 21:53   ` Alexei Starovoitov
2020-08-21  2:22     ` Hao Luo
2020-08-19 22:40 ` [PATCH bpf-next v1 2/8] bpf: Propagate BPF_PSEUDO_BTF_ID to uapi headers in /tools Hao Luo
2020-08-20 16:44   ` Yonghong Song
2020-08-19 22:40 ` [PATCH bpf-next v1 3/8] bpf: Introduce help function to validate ksym's type Hao Luo
2020-08-20 17:20   ` Yonghong Song
2020-08-21 21:50     ` Andrii Nakryiko
2020-08-22  0:43       ` Hao Luo
2020-08-22  2:43         ` Andrii Nakryiko
2020-08-22  7:04           ` Hao Luo
2020-08-19 22:40 ` [PATCH bpf-next v1 4/8] bpf/libbpf: BTF support for typed ksyms Hao Luo
2020-08-21 22:37   ` Andrii Nakryiko
2020-08-27 22:29     ` Hao Luo
2020-09-01 18:11       ` Andrii Nakryiko
2020-09-01 20:35         ` Hao Luo
2020-09-01 23:54           ` Andrii Nakryiko
2020-09-02  0:46             ` Hao Luo
2020-08-19 22:40 ` [PATCH bpf-next v1 5/8] bpf/selftests: ksyms_btf to test " Hao Luo
2020-08-20 17:28   ` Yonghong Song
2020-08-21 23:03     ` Andrii Nakryiko
2020-08-22  7:26       ` Hao Luo
2020-08-22  7:35         ` Andrii Nakryiko
2020-08-19 22:40 ` [PATCH bpf-next v1 6/8] bpf: Introduce bpf_per_cpu_ptr() Hao Luo
2020-08-22  3:26   ` Andrii Nakryiko
2020-08-22  3:31     ` Andrii Nakryiko
2020-08-22  7:49       ` Hao Luo
2020-08-22  7:55         ` Andrii Nakryiko
2020-08-25  1:03           ` Hao Luo
2020-08-19 22:40 ` [PATCH bpf-next v1 7/8] bpf: Propagate bpf_per_cpu_ptr() to /tools Hao Luo
2020-08-20 17:30   ` Yonghong Song
2020-08-19 22:40 ` [PATCH bpf-next v1 8/8] bpf/selftests: Test for bpf_per_cpu_ptr() Hao Luo
2020-08-22  3:30   ` Andrii Nakryiko
2020-08-28  3:42     ` Hao Luo
2020-09-01 18:12       ` Andrii Nakryiko
2020-09-01 19:47         ` Hao Luo

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