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@xxxxxxxxxx> --- Documentation/bpf/btf.rst | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~ -- 2.31.1
