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Diffstat (limited to 'Documentation/bpf/btf.rst')
| -rw-r--r-- | Documentation/bpf/btf.rst | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst index 846354cd2d69..9ad4218a751f 100644 --- a/Documentation/bpf/btf.rst +++ b/Documentation/bpf/btf.rst @@ -85,6 +85,7 @@ sequentially and type id is assigned to each recognized type starting from id #define BTF_KIND_VAR 14 /* Variable */ #define BTF_KIND_DATASEC 15 /* Section */ #define BTF_KIND_FLOAT 16 /* Floating point */ + #define BTF_KIND_DECL_TAG 17 /* Decl Tag */ Note that the type section encodes debug info, not just pure types. ``BTF_KIND_FUNC`` is not a type, and it represents a defined subprogram. @@ -106,7 +107,7 @@ Each type contains the following common data:: * "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, - * FUNC and FUNC_PROTO. + * FUNC, FUNC_PROTO and DECL_TAG. * "type" is a type_id referring to another type. */ union { @@ -465,6 +466,32 @@ map definition. No additional type data follow ``btf_type``. +2.2.17 BTF_KIND_DECL_TAG +~~~~~~~~~~~~~~~~~~~~~~~~ + +``struct btf_type`` encoding requirement: + * ``name_off``: offset to a non-empty string + * ``info.kind_flag``: 0 + * ``info.kind``: BTF_KIND_DECL_TAG + * ``info.vlen``: 0 + * ``type``: ``struct``, ``union``, ``func``, ``var`` or ``typedef`` + +``btf_type`` is followed by ``struct btf_decl_tag``.:: + + struct btf_decl_tag { + __u32 component_idx; + }; + +The ``name_off`` encodes btf_decl_tag attribute string. +The ``type`` should be ``struct``, ``union``, ``func``, ``var`` or ``typedef``. +For ``var`` or ``typedef`` type, ``btf_decl_tag.component_idx`` must be ``-1``. +For the other three types, if the btf_decl_tag attribute is +applied to the ``struct``, ``union`` or ``func`` itself, +``btf_decl_tag.component_idx`` must be ``-1``. Otherwise, +the attribute is applied to a ``struct``/``union`` member or +a ``func`` argument, and ``btf_decl_tag.component_idx`` should be a +valid index (starting from 0) pointing to a member or an argument. + 3. BTF Kernel API ***************** |