Commit 2667a262 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov

bpf: btf: Add BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO

This patch adds BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO
to support the function debug info.

BTF_KIND_FUNC_PROTO must not have a name (i.e. !t->name_off)
and it is followed by >= 0 'struct bpf_param' objects to
describe the function arguments.

The BTF_KIND_FUNC must have a valid name and it must
refer back to a BTF_KIND_FUNC_PROTO.

The above is the conclusion after the discussion between
Edward Cree, Alexei, Daniel, Yonghong and Martin.

By combining BTF_KIND_FUNC and BTF_LIND_FUNC_PROTO,
a complete function signature can be obtained.  It will be
used in the later patches to learn the function signature of
a running bpf program.
Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent b47a0bd2
......@@ -40,7 +40,8 @@ struct btf_type {
/* "size" is used by INT, ENUM, STRUCT and UNION.
* "size" tells the size of the type it is describing.
*
* "type" is used by PTR, TYPEDEF, VOLATILE, CONST and RESTRICT.
* "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
* FUNC and FUNC_PROTO.
* "type" is a type_id referring to another type.
*/
union {
......@@ -64,8 +65,10 @@ struct btf_type {
#define BTF_KIND_VOLATILE 9 /* Volatile */
#define BTF_KIND_CONST 10 /* Const */
#define BTF_KIND_RESTRICT 11 /* Restrict */
#define BTF_KIND_MAX 11
#define NR_BTF_KINDS 12
#define BTF_KIND_FUNC 12 /* Function */
#define BTF_KIND_FUNC_PROTO 13 /* Function Proto */
#define BTF_KIND_MAX 13
#define NR_BTF_KINDS 14
/* For some specific BTF_KIND, "struct btf_type" is immediately
* followed by extra data.
......@@ -110,4 +113,13 @@ struct btf_member {
__u32 offset; /* offset in bits */
};
/* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param".
* The exact number of btf_param is stored in the vlen (of the
* info in "struct btf_type").
*/
struct btf_param {
__u32 name_off;
__u32 type;
};
#endif /* _UAPI__LINUX_BTF_H__ */
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