From: Yonghong Song <yhs@fb.com> mainline inclusion from mainline-5.16-rc1 commit 5a8671349dd1cfe6255c524d37d6265df7483f36 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------------------------- Add BTF_KIND_DECL_TAG typedef support in btf.rst. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211021195649.4020514-1-yhs@fb.com (cherry picked from commit 5a8671349dd1cfe6255c524d37d6265df7483f36) Signed-off-by: Wang Yufen <wangyufen@huawei.com> Conflicts: Documentation/bpf/btf.rst Signed-off-by: Wang Yufen <wangyufen@huawei.com> --- Documentation/bpf/btf.rst | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst index 44dc789de2b4..f82137aa4bd9 100644 --- a/Documentation/bpf/btf.rst +++ b/Documentation/bpf/btf.rst @@ -452,6 +452,32 @@ map definition. * ``offset``: the in-section offset of the variable * ``size``: the size of the variable in bytes +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 ***************** -- 2.20.1