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Message-ID: <20190425223011.284686-3-andriin@fb.com>
Date: Thu, 25 Apr 2019 15:30:09 -0700
From: Andrii Nakryiko <andriin@...com>
To: <andrii.nakryiko@...il.com>, <netdev@...r.kernel.org>,
<bpf@...r.kernel.org>
Subject: [PATCH v4 bpf-next 2/4] bpftool/docs: add btf sub-command documentation
Document usage and sample output format for `btf dump` sub-command.
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: Alexei Starovoitov <ast@...com>
Cc: Yonghong Song <yhs@...com>
Cc: Martin KaFai Lau <kafai@...com>
Cc: Song Liu <songliubraving@...com>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Acked-by: Yonghong Song <yhs@...com>
Signed-off-by: Andrii Nakryiko <andriin@...com>
---
.../bpf/bpftool/Documentation/bpftool-btf.rst | 222 ++++++++++++++++++
.../bpftool/Documentation/bpftool-cgroup.rst | 3 +-
.../bpftool/Documentation/bpftool-feature.rst | 3 +-
.../bpf/bpftool/Documentation/bpftool-map.rst | 3 +-
.../bpf/bpftool/Documentation/bpftool-net.rst | 3 +-
.../bpftool/Documentation/bpftool-perf.rst | 3 +-
.../bpftool/Documentation/bpftool-prog.rst | 3 +-
tools/bpf/bpftool/Documentation/bpftool.rst | 3 +-
8 files changed, 236 insertions(+), 7 deletions(-)
create mode 100644 tools/bpf/bpftool/Documentation/bpftool-btf.rst
diff --git a/tools/bpf/bpftool/Documentation/bpftool-btf.rst b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
new file mode 100644
index 000000000000..2dbc1413fabd
--- /dev/null
+++ b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
@@ -0,0 +1,222 @@
+================
+bpftool-btf
+================
+-------------------------------------------------------------------------------
+tool for inspection of BTF data
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+SYNOPSIS
+========
+
+ **bpftool** [*OPTIONS*] **btf** *COMMAND*
+
+ *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
+
+ *COMMANDS* := { **dump** | **help** }
+
+BTF COMMANDS
+=============
+
+| **bpftool** **btf dump** *BTF_SRC*
+| **bpftool** **btf help**
+|
+| *BTF_SRC* := { **id** *BTF_ID* | **prog** *PROG* | **map** *MAP* [{**key** | **value** | **kv** | **all**}] | **file** *FILE* }
+| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
+| *PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* }
+
+DESCRIPTION
+===========
+ **bpftool btf dump** *BTF_SRC*
+ Dump BTF entries from a given *BTF_SRC*.
+
+ When **id** is specified, BTF object with that ID will be
+ loaded and all its BTF types emitted.
+
+ When **map** is provided, it's expected that map has
+ associated BTF object with BTF types describing key and
+ value. It's possible to select whether to dump only BTF
+ type(s) associated with key (**key**), value (**value**),
+ both key and value (**kv**), or all BTF types present in
+ associated BTF object (**all**). If not specified, **kv**
+ is assumed.
+
+ When **prog** is provided, it's expected that program has
+ associated BTF object with BTF types.
+
+ When specifying *FILE*, an ELF file is expected, containing
+ .BTF section with well-defined BTF binary format data,
+ typically produced by clang or pahole.
+
+ **bpftool btf help**
+ Print short help message.
+
+OPTIONS
+=======
+ -h, --help
+ Print short generic help message (similar to **bpftool help**).
+
+ -V, --version
+ Print version number (similar to **bpftool version**).
+
+ -j, --json
+ Generate JSON output. For commands that cannot produce JSON, this
+ option has no effect.
+
+ -p, --pretty
+ Generate human-readable JSON output. Implies **-j**.
+
+EXAMPLES
+========
+**# bpftool btf dump id 1226**
+::
+
+ [1] PTR '(anon)' type_id=2
+ [2] STRUCT 'dummy_tracepoint_args' size=16 vlen=2
+ 'pad' type_id=3 bits_offset=0
+ 'sock' type_id=4 bits_offset=64
+ [3] INT 'long long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
+ [4] PTR '(anon)' type_id=5
+ [5] FWD 'sock' fwd_kind=union
+
+This gives an example of default output for all supported BTF kinds.
+
+**$ cat prog.c**
+::
+
+ struct fwd_struct;
+
+ enum my_enum {
+ VAL1 = 3,
+ VAL2 = 7,
+ };
+
+ typedef struct my_struct my_struct_t;
+
+ struct my_struct {
+ const unsigned int const_int_field;
+ int bitfield_field: 4;
+ char arr_field[16];
+ const struct fwd_struct *restrict fwd_field;
+ enum my_enum enum_field;
+ volatile my_struct_t *typedef_ptr_field;
+ };
+
+ union my_union {
+ int a;
+ struct my_struct b;
+ };
+
+ struct my_struct struct_global_var __attribute__((section("data_sec"))) = {
+ .bitfield_field = 3,
+ .enum_field = VAL1,
+ };
+ int global_var __attribute__((section("data_sec"))) = 7;
+
+ __attribute__((noinline))
+ int my_func(union my_union *arg1, int arg2)
+ {
+ static int static_var __attribute__((section("data_sec"))) = 123;
+ static_var++;
+ return static_var;
+ }
+
+**$ bpftool btf dump file prog.o**
+::
+
+ [1] PTR '(anon)' type_id=2
+ [2] UNION 'my_union' size=48 vlen=2
+ 'a' type_id=3 bits_offset=0
+ 'b' type_id=4 bits_offset=0
+ [3] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
+ [4] STRUCT 'my_struct' size=48 vlen=6
+ 'const_int_field' type_id=5 bits_offset=0
+ 'bitfield_field' type_id=3 bits_offset=32 bitfield_size=4
+ 'arr_field' type_id=8 bits_offset=40
+ 'fwd_field' type_id=10 bits_offset=192
+ 'enum_field' type_id=14 bits_offset=256
+ 'typedef_ptr_field' type_id=15 bits_offset=320
+ [5] CONST '(anon)' type_id=6
+ [6] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)
+ [7] INT 'char' size=1 bits_offset=0 nr_bits=8 encoding=SIGNED
+ [8] ARRAY '(anon)' type_id=7 index_type_id=9 nr_elems=16
+ [9] INT '__ARRAY_SIZE_TYPE__' size=4 bits_offset=0 nr_bits=32 encoding=(none)
+ [10] RESTRICT '(anon)' type_id=11
+ [11] PTR '(anon)' type_id=12
+ [12] CONST '(anon)' type_id=13
+ [13] FWD 'fwd_struct' fwd_kind=union
+ [14] ENUM 'my_enum' size=4 vlen=2
+ 'VAL1' val=3
+ 'VAL2' val=7
+ [15] PTR '(anon)' type_id=16
+ [16] VOLATILE '(anon)' type_id=17
+ [17] TYPEDEF 'my_struct_t' type_id=4
+ [18] FUNC_PROTO '(anon)' ret_type_id=3 vlen=2
+ 'arg1' type_id=1
+ 'arg2' type_id=3
+ [19] FUNC 'my_func' type_id=18
+ [20] VAR 'struct_global_var' type_id=4, linkage=global-alloc
+ [21] VAR 'global_var' type_id=3, linkage=global-alloc
+ [22] VAR 'my_func.static_var' type_id=3, linkage=static
+ [23] DATASEC 'data_sec' size=0 vlen=3
+ type_id=20 offset=0 size=48
+ type_id=21 offset=0 size=4
+ type_id=22 offset=52 size=4
+
+The following commands print BTF types associated with specified map's key,
+value, both key and value, and all BTF types, respectively. By default, both
+key and value types will be printed.
+
+**# bpftool btf dump map id 123 key**
+
+::
+
+ [39] TYPEDEF 'u32' type_id=37
+
+**# bpftool btf dump map id 123 value**
+
+::
+
+ [86] PTR '(anon)' type_id=87
+
+**# bpftool btf dump map id 123 kv**
+
+::
+
+ [39] TYPEDEF 'u32' type_id=37
+ [86] PTR '(anon)' type_id=87
+
+**# bpftool btf dump map id 123 all**
+
+::
+
+ [1] PTR '(anon)' type_id=0
+ .
+ .
+ .
+ [2866] ARRAY '(anon)' type_id=52 index_type_id=51 nr_elems=4
+
+All the standard ways to specify map or program are supported:
+
+**# bpftool btf dump map id 123**
+
+**# bpftool btf dump map pinned /sys/fs/bpf/map_name**
+
+**# bpftool btf dump prog id 456**
+
+**# bpftool btf dump prog tag b88e0a09b1d9759d**
+
+**# bpftool btf dump prog pinned /sys/fs/bpf/prog_name**
+
+SEE ALSO
+========
+ **bpf**\ (2),
+ **bpf-helpers**\ (7),
+ **bpftool**\ (8),
+ **bpftool-map**\ (8),
+ **bpftool-prog**\ (8),
+ **bpftool-cgroup**\ (8),
+ **bpftool-feature**\ (8),
+ **bpftool-net**\ (8),
+ **bpftool-perf**\ (8)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst b/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst
index 89b6b10e2183..ac26876389c2 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst
@@ -145,4 +145,5 @@ SEE ALSO
**bpftool-map**\ (8),
**bpftool-feature**\ (8),
**bpftool-net**\ (8),
- **bpftool-perf**\ (8)
+ **bpftool-perf**\ (8),
+ **bpftool-btf**\ (8)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-feature.rst b/tools/bpf/bpftool/Documentation/bpftool-feature.rst
index 10177343b7ce..14180e887082 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-feature.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-feature.rst
@@ -82,4 +82,5 @@ SEE ALSO
**bpftool-map**\ (8),
**bpftool-cgroup**\ (8),
**bpftool-net**\ (8),
- **bpftool-perf**\ (8)
+ **bpftool-perf**\ (8),
+ **bpftool-btf**\ (8)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst
index 55ecf80ca03e..13ef27b39f20 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-map.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst
@@ -258,4 +258,5 @@ SEE ALSO
**bpftool-cgroup**\ (8),
**bpftool-feature**\ (8),
**bpftool-net**\ (8),
- **bpftool-perf**\ (8)
+ **bpftool-perf**\ (8),
+ **bpftool-btf**\ (8)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-net.rst b/tools/bpf/bpftool/Documentation/bpftool-net.rst
index 6b692b428373..934580850f42 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-net.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-net.rst
@@ -143,4 +143,5 @@ SEE ALSO
**bpftool-map**\ (8),
**bpftool-cgroup**\ (8),
**bpftool-feature**\ (8),
- **bpftool-perf**\ (8)
+ **bpftool-perf**\ (8),
+ **bpftool-btf**\ (8)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-perf.rst b/tools/bpf/bpftool/Documentation/bpftool-perf.rst
index 86154740fabb..0c7576523a21 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-perf.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-perf.rst
@@ -85,4 +85,5 @@ SEE ALSO
**bpftool-map**\ (8),
**bpftool-cgroup**\ (8),
**bpftool-feature**\ (8),
- **bpftool-net**\ (8)
+ **bpftool-net**\ (8),
+ **bpftool-btf**\ (8)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index 2f183ffd8351..e8118544d118 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -271,4 +271,5 @@ SEE ALSO
**bpftool-cgroup**\ (8),
**bpftool-feature**\ (8),
**bpftool-net**\ (8),
- **bpftool-perf**\ (8)
+ **bpftool-perf**\ (8),
+ **bpftool-btf**\ (8)
diff --git a/tools/bpf/bpftool/Documentation/bpftool.rst b/tools/bpf/bpftool/Documentation/bpftool.rst
index deb2ca911ddf..3e562d7fd56f 100644
--- a/tools/bpf/bpftool/Documentation/bpftool.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool.rst
@@ -76,4 +76,5 @@ SEE ALSO
**bpftool-cgroup**\ (8),
**bpftool-feature**\ (8),
**bpftool-net**\ (8),
- **bpftool-perf**\ (8)
+ **bpftool-perf**\ (8),
+ **bpftool-btf**\ (8)
--
2.17.1
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