Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'bpf: add support for BTF_KIND_DECL_TAG typedef'
Yonghong Song says:
====================
Latest upstream llvm-project added support for btf_decl_tag attributes
for typedef declarations ([1], [2]). Similar to other btf_decl_tag cases,
func/func_param/global_var/struct/union/field, btf_decl_tag with typedef
declaration can carry information from kernel source to clang compiler
and then to dwarf/BTF, for bpf verification or other use cases.
This patch set added kernel support for BTF_KIND_DECL_TAG to typedef
declaration (Patch 1). Additional selftests are added to cover
unit testing, dedup, or bpf program usage of btf_decl_tag with typedef.
(Patches 2, 3 and 4). The btf documentation is updated to include
BTF_KIND_DECL_TAG typedef (Patch 5).
[1] https://reviews.llvm.org/D110127
[2] https://reviews.llvm.org/D112259
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
+89
-13
+3
-3
Documentation/bpf/btf.rst
+3
-3
Documentation/bpf/btf.rst
···
474
474
* ``info.kind_flag``: 0
475
475
* ``info.kind``: BTF_KIND_DECL_TAG
476
476
* ``info.vlen``: 0
477
-
* ``type``: ``struct``, ``union``, ``func`` or ``var``
477
+
* ``type``: ``struct``, ``union``, ``func``, ``var`` or ``typedef``
478
478
479
479
``btf_type`` is followed by ``struct btf_decl_tag``.::
480
480
···
483
483
};
484
484
485
485
The ``name_off`` encodes btf_decl_tag attribute string.
486
-
The ``type`` should be ``struct``, ``union``, ``func`` or ``var``.
487
-
For ``var`` type, ``btf_decl_tag.component_idx`` must be ``-1``.
486
+
The ``type`` should be ``struct``, ``union``, ``func``, ``var`` or ``typedef``.
487
+
For ``var`` or ``typedef`` type, ``btf_decl_tag.component_idx`` must be ``-1``.
488
488
For the other three types, if the btf_decl_tag attribute is
489
489
applied to the ``struct``, ``union`` or ``func`` itself,
490
490
``btf_decl_tag.component_idx`` must be ``-1``. Otherwise,
+2
-2
kernel/bpf/btf.c
+2
-2
kernel/bpf/btf.c
···
468
468
static bool btf_type_is_decl_tag_target(const struct btf_type *t)
469
469
{
470
470
return btf_type_is_func(t) || btf_type_is_struct(t) ||
471
-
btf_type_is_var(t);
471
+
btf_type_is_var(t) || btf_type_is_typedef(t);
472
472
}
473
473
474
474
u32 btf_nr_types(const struct btf *btf)
···
3885
3885
3886
3886
component_idx = btf_type_decl_tag(t)->component_idx;
3887
3887
if (component_idx != -1) {
3888
-
if (btf_type_is_var(next_type)) {
3888
+
if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
3889
3889
btf_verifier_log_type(env, v->t, "Invalid component_idx");
3890
3890
return -EINVAL;
3891
3891
}
+77
-6
tools/testing/selftests/bpf/prog_tests/btf.c
+77
-6
tools/testing/selftests/bpf/prog_tests/btf.c
···
3903
3903
.btf_load_err = true,
3904
3904
.err_str = "Invalid component_idx",
3905
3905
},
3906
+
{
3907
+
.descr = "decl_tag test #13, typedef, well-formed",
3908
+
.raw_types = {
3909
+
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
3910
+
BTF_TYPEDEF_ENC(NAME_TBD, 1), /* [2] */
3911
+
BTF_DECL_TAG_ENC(NAME_TBD, 2, -1),
3912
+
BTF_END_RAW,
3913
+
},
3914
+
BTF_STR_SEC("\0t\0tag"),
3915
+
.map_type = BPF_MAP_TYPE_ARRAY,
3916
+
.map_name = "tag_type_check_btf",
3917
+
.key_size = sizeof(int),
3918
+
.value_size = 4,
3919
+
.key_type_id = 1,
3920
+
.value_type_id = 1,
3921
+
.max_entries = 1,
3922
+
},
3923
+
{
3924
+
.descr = "decl_tag test #14, typedef, invalid component_idx",
3925
+
.raw_types = {
3926
+
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
3927
+
BTF_TYPEDEF_ENC(NAME_TBD, 1), /* [2] */
3928
+
BTF_DECL_TAG_ENC(NAME_TBD, 2, 0),
3929
+
BTF_END_RAW,
3930
+
},
3931
+
BTF_STR_SEC("\0local\0tag"),
3932
+
.map_type = BPF_MAP_TYPE_ARRAY,
3933
+
.map_name = "tag_type_check_btf",
3934
+
.key_size = sizeof(int),
3935
+
.value_size = 4,
3936
+
.key_type_id = 1,
3937
+
.value_type_id = 1,
3938
+
.max_entries = 1,
3939
+
.btf_load_err = true,
3940
+
.err_str = "Invalid component_idx",
3941
+
},
3906
3942
3907
3943
}; /* struct btf_raw_test raw_tests[] */
3908
3944
···
6877
6841
BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 8),
6878
6842
BTF_FUNC_ENC(NAME_TBD, 12), /* [13] func */
6879
6843
BTF_TYPE_FLOAT_ENC(NAME_TBD, 2), /* [14] float */
6880
-
BTF_DECL_TAG_ENC(NAME_TBD, 13, -1), /* [15] tag */
6881
-
BTF_DECL_TAG_ENC(NAME_TBD, 13, 1), /* [16] tag */
6844
+
BTF_DECL_TAG_ENC(NAME_TBD, 13, -1), /* [15] decl_tag */
6845
+
BTF_DECL_TAG_ENC(NAME_TBD, 13, 1), /* [16] decl_tag */
6846
+
BTF_DECL_TAG_ENC(NAME_TBD, 7, -1), /* [17] decl_tag */
6882
6847
BTF_END_RAW,
6883
6848
},
6884
-
BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M\0N\0O\0P"),
6849
+
BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M\0N\0O\0P\0Q"),
6885
6850
},
6886
6851
.expect = {
6887
6852
.raw_types = {
···
6906
6869
BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 8),
6907
6870
BTF_FUNC_ENC(NAME_TBD, 12), /* [13] func */
6908
6871
BTF_TYPE_FLOAT_ENC(NAME_TBD, 2), /* [14] float */
6909
-
BTF_DECL_TAG_ENC(NAME_TBD, 13, -1), /* [15] tag */
6910
-
BTF_DECL_TAG_ENC(NAME_TBD, 13, 1), /* [16] tag */
6872
+
BTF_DECL_TAG_ENC(NAME_TBD, 13, -1), /* [15] decl_tag */
6873
+
BTF_DECL_TAG_ENC(NAME_TBD, 13, 1), /* [16] decl_tag */
6874
+
BTF_DECL_TAG_ENC(NAME_TBD, 7, -1), /* [17] decl_tag */
6911
6875
BTF_END_RAW,
6912
6876
},
6913
-
BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M\0N\0O\0P"),
6877
+
BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M\0N\0O\0P\0Q"),
6914
6878
},
6915
6879
.opts = {
6916
6880
.dont_resolve_fwds = false,
···
7201
7163
BTF_END_RAW,
7202
7164
},
7203
7165
BTF_STR_SEC("\0t\0m1\0m2\0tag1\0tag2\0tag3"),
7166
+
},
7167
+
.opts = {
7168
+
.dont_resolve_fwds = false,
7169
+
},
7170
+
},
7171
+
{
7172
+
.descr = "dedup: typedef tags",
7173
+
.input = {
7174
+
.raw_types = {
7175
+
/* int */
7176
+
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
7177
+
BTF_TYPEDEF_ENC(NAME_NTH(1), 1), /* [2] */
7178
+
BTF_TYPEDEF_ENC(NAME_NTH(1), 1), /* [3] */
7179
+
/* tag -> t: tag1, tag2 */
7180
+
BTF_DECL_TAG_ENC(NAME_NTH(2), 2, -1), /* [4] */
7181
+
BTF_DECL_TAG_ENC(NAME_NTH(3), 2, -1), /* [5] */
7182
+
/* tag -> t: tag1, tag3 */
7183
+
BTF_DECL_TAG_ENC(NAME_NTH(2), 3, -1), /* [6] */
7184
+
BTF_DECL_TAG_ENC(NAME_NTH(4), 3, -1), /* [7] */
7185
+
BTF_END_RAW,
7186
+
},
7187
+
BTF_STR_SEC("\0t\0tag1\0tag2\0tag3"),
7188
+
},
7189
+
.expect = {
7190
+
.raw_types = {
7191
+
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
7192
+
BTF_TYPEDEF_ENC(NAME_NTH(1), 1), /* [2] */
7193
+
BTF_DECL_TAG_ENC(NAME_NTH(2), 2, -1), /* [3] */
7194
+
BTF_DECL_TAG_ENC(NAME_NTH(3), 2, -1), /* [4] */
7195
+
BTF_DECL_TAG_ENC(NAME_NTH(4), 2, -1), /* [5] */
7196
+
BTF_END_RAW,
7197
+
},
7198
+
BTF_STR_SEC("\0t\0tag1\0tag2\0tag3"),
7204
7199
},
7205
7200
.opts = {
7206
7201
.dont_resolve_fwds = false,
+7
-2
tools/testing/selftests/bpf/progs/tag.c
+7
-2
tools/testing/selftests/bpf/progs/tag.c
···
24
24
int c;
25
25
} __tag1 __tag2;
26
26
27
+
typedef struct {
28
+
int a;
29
+
int b;
30
+
} value_t __tag1 __tag2;
31
+
27
32
struct {
28
33
__uint(type, BPF_MAP_TYPE_HASH);
29
34
__uint(max_entries, 3);
30
35
__type(key, struct key_t);
31
-
__type(value, __u64);
36
+
__type(value, value_t);
32
37
} hashmap1 SEC(".maps");
33
38
34
39
35
40
static __noinline int foo(int x __tag1 __tag2) __tag1 __tag2
36
41
{
37
42
struct key_t key;
38
-
__u64 val = 1;
43
+
value_t val = {};
39
44
40
45
key.a = key.b = key.c = x;
41
46
bpf_map_update_elem(&hashmap1, &key, &val, 0);