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authorIndu Bhagat <indu.bhagat@oracle.com>2022-07-14 15:33:10 -0700
committerAlexei Starovoitov <ast@kernel.org>2022-07-19 09:42:09 -0700
commite5e23424e51edbd8b3fabae382aeec0bb8926cf1 (patch)
tree3f11751a6b0d71f55c1dba54235c8f17f02717f5 /Documentation/bpf
parent3908fcddc65d04e069b03be49b33fae90e424631 (diff)
docs/bpf: Update documentation for BTF_KIND_FUNC
The vlen bits in the BTF type of kind BTF_KIND_FUNC are used to convey the linkage information for functions. The Linux kernel only supports linkage values of BTF_FUNC_STATIC and BTF_FUNC_GLOBAL at this time. Signed-off-by: Indu Bhagat <indu.bhagat@oracle.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/r/20220714223310.1140097-1-indu.bhagat@oracle.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'Documentation/bpf')
-rw-r--r--Documentation/bpf/btf.rst6
1 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst
index f49aeef62d0c..cf8722f96090 100644
--- a/Documentation/bpf/btf.rst
+++ b/Documentation/bpf/btf.rst
@@ -369,7 +369,8 @@ No additional type data follow ``btf_type``.
* ``name_off``: offset to a valid C identifier
* ``info.kind_flag``: 0
* ``info.kind``: BTF_KIND_FUNC
- * ``info.vlen``: 0
+ * ``info.vlen``: linkage information (BTF_FUNC_STATIC, BTF_FUNC_GLOBAL
+ or BTF_FUNC_EXTERN)
* ``type``: a BTF_KIND_FUNC_PROTO type
No additional type data follow ``btf_type``.
@@ -380,6 +381,9 @@ type. The BTF_KIND_FUNC may in turn be referenced by a func_info in the
:ref:`BTF_Ext_Section` (ELF) or in the arguments to :ref:`BPF_Prog_Load`
(ABI).
+Currently, only linkage values of BTF_FUNC_STATIC and BTF_FUNC_GLOBAL are
+supported in the kernel.
+
2.2.13 BTF_KIND_FUNC_PROTO
~~~~~~~~~~~~~~~~~~~~~~~~~~