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[bpf-next,v2,10/10] docs/bpf: Update documentation for BTF_KIND_TYPE_TAG support

Message ID 20211111232640.793157-1-yhs@fb.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series Support BTF_KIND_TYPE_TAG for btf_type_tag attributes | expand

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bpf/vmtest-bpf-next success VM_Test
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 7 maintainers not CCed: linux-doc@vger.kernel.org netdev@vger.kernel.org john.fastabend@gmail.com kafai@fb.com corbet@lwn.net songliubraving@fb.com kpsingh@kernel.org
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netdev/verify_fixes success No Fixes tag
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bpf/vmtest-bpf-next-PR success PR summary

Commit Message

Yonghong Song Nov. 11, 2021, 11:26 p.m. UTC
Add BTF_KIND_TYPE_TAG documentation in btf.rst.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 Documentation/bpf/btf.rst | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst
index 9ad4218a751f..d0ec40d00c28 100644
--- a/Documentation/bpf/btf.rst
+++ b/Documentation/bpf/btf.rst
@@ -86,6 +86,7 @@  sequentially and type id is assigned to each recognized type starting from id
     #define BTF_KIND_DATASEC        15      /* Section      */
     #define BTF_KIND_FLOAT          16      /* Floating point       */
     #define BTF_KIND_DECL_TAG       17      /* Decl Tag     */
+    #define BTF_KIND_TYPE_TAG       18      /* Type 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.
@@ -107,7 +108,7 @@  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, FUNC_PROTO and DECL_TAG.
+         * FUNC, FUNC_PROTO, DECL_TAG and TYPE_TAG.
          * "type" is a type_id referring to another type.
          */
         union {
@@ -492,6 +493,16 @@  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.
 
+2.2.17 BTF_KIND_TYPE_TAG
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+``struct btf_type`` encoding requirement:
+ * ``name_off``: offset to a non-empty string
+ * ``info.kind_flag``: 0
+ * ``info.kind``: BTF_KIND_TYPE_TAG
+ * ``info.vlen``: 0
+ * ``type``: the type with ``btf_type_tag`` attribute
+
 3. BTF Kernel API
 *****************