Add libbpf support for BTF_KIND_TYPE_TAG.
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
tools/lib/bpf/btf.c | 23 +++++++++++++++++++++++
tools/lib/bpf/btf.h | 9 ++++++++-
tools/lib/bpf/btf_dump.c | 9 +++++++++
tools/lib/bpf/libbpf.c | 31 ++++++++++++++++++++++++++++++-
tools/lib/bpf/libbpf.map | 1 +
tools/lib/bpf/libbpf_internal.h | 2 ++
6 files changed, 73 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 7e4c5586bd87..667919334fce 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -299,6 +299,7 @@ static int btf_type_size(const struct btf_type *t)
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
case BTF_KIND_FLOAT:
+ case BTF_KIND_TYPE_TAG:
return base_size;
case BTF_KIND_INT:
return base_size + sizeof(__u32);
@@ -349,6 +350,7 @@ static int btf_bswap_type_rest(struct btf_type *t)
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
case BTF_KIND_FLOAT:
+ case BTF_KIND_TYPE_TAG:
return 0;
case BTF_KIND_INT:
*(__u32 *)(t + 1) = bswap_32(*(__u32 *)(t + 1));
@@ -649,6 +651,7 @@ int btf__align_of(const struct btf *btf, __u32 id)
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
+ case BTF_KIND_TYPE_TAG:
return btf__align_of(btf, t->type);
case BTF_KIND_ARRAY:
return btf__align_of(btf, btf_array(t)->type);
@@ -2235,6 +2238,22 @@ int btf__add_restrict(struct btf *btf, int ref_type_id)
return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id);
}
+/*
+ * Append new BTF_KIND_TYPE_TAG type with:
+ * - *value*, non-empty/non-NULL tag value;
+ * - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id)
+{
+ if (!value|| !value[0])
+ return libbpf_err(-EINVAL);
+
+ return btf_add_ref_kind(btf, BTF_KIND_TYPE_TAG, value, ref_type_id);
+}
+
/*
* Append new BTF_KIND_FUNC type with:
* - *name*, non-empty/non-NULL name;
@@ -3625,6 +3644,7 @@ static int btf_dedup_prep(struct btf_dedup *d)
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
case BTF_KIND_FLOAT:
+ case BTF_KIND_TYPE_TAG:
h = btf_hash_common(t);
break;
case BTF_KIND_INT:
@@ -3685,6 +3705,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
case BTF_KIND_VAR:
case BTF_KIND_DATASEC:
case BTF_KIND_DECL_TAG:
+ case BTF_KIND_TYPE_TAG:
return 0;
case BTF_KIND_INT:
@@ -4289,6 +4310,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
case BTF_KIND_PTR:
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
+ case BTF_KIND_TYPE_TAG:
ref_type_id = btf_dedup_ref_type(d, t->type);
if (ref_type_id < 0)
return ref_type_id;
@@ -4595,6 +4617,7 @@ int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ct
case BTF_KIND_FUNC:
case BTF_KIND_VAR:
case BTF_KIND_DECL_TAG:
+ case BTF_KIND_TYPE_TAG:
return visit(&t->type, ctx);
case BTF_KIND_ARRAY: {
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index bc005ba3ceec..129c2acc8493 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -227,6 +227,7 @@ LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_
LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id);
LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id);
LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id);
+LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id);
/* func and func_proto construction APIs */
LIBBPF_API int btf__add_func(struct btf *btf, const char *name,
@@ -403,7 +404,8 @@ static inline bool btf_is_mod(const struct btf_type *t)
return kind == BTF_KIND_VOLATILE ||
kind == BTF_KIND_CONST ||
- kind == BTF_KIND_RESTRICT;
+ kind == BTF_KIND_RESTRICT ||
+ kind == BTF_KIND_TYPE_TAG;
}
static inline bool btf_is_func(const struct btf_type *t)
@@ -436,6 +438,11 @@ static inline bool btf_is_decl_tag(const struct btf_type *t)
return btf_kind(t) == BTF_KIND_DECL_TAG;
}
+static inline bool btf_is_type_tag(const struct btf_type *t)
+{
+ return btf_kind(t) == BTF_KIND_TYPE_TAG;
+}
+
static inline __u8 btf_int_encoding(const struct btf_type *t)
{
return BTF_INT_ENCODING(*(__u32 *)(t + 1));
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 17db62b5002e..380250a5bfcd 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -317,6 +317,7 @@ static int btf_dump_mark_referenced(struct btf_dump *d)
case BTF_KIND_FUNC:
case BTF_KIND_VAR:
case BTF_KIND_DECL_TAG:
+ case BTF_KIND_TYPE_TAG:
d->type_states[t->type].referenced = 1;
break;
@@ -560,6 +561,7 @@ static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr)
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
+ case BTF_KIND_TYPE_TAG:
return btf_dump_order_type(d, t->type, through_ptr);
case BTF_KIND_FUNC_PROTO: {
@@ -734,6 +736,7 @@ static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
+ case BTF_KIND_TYPE_TAG:
btf_dump_emit_type(d, t->type, cont_id);
break;
case BTF_KIND_ARRAY:
@@ -1154,6 +1157,7 @@ static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
case BTF_KIND_FUNC_PROTO:
+ case BTF_KIND_TYPE_TAG:
id = t->type;
break;
case BTF_KIND_ARRAY:
@@ -1322,6 +1326,11 @@ static void btf_dump_emit_type_chain(struct btf_dump *d,
case BTF_KIND_RESTRICT:
btf_dump_printf(d, " restrict");
break;
+ case BTF_KIND_TYPE_TAG:
+ btf_dump_emit_mods(d, decls);
+ name = btf_name_of(d, t->name_off);
+ btf_dump_printf(d, " __attribute__((btf_type_tag(\"%s\")))", name);
+ break;
case BTF_KIND_ARRAY: {
const struct btf_array *a = btf_array(t);
const struct btf_type *next_t;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d869ebee1e27..f6bf8ce24bbd 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -197,6 +197,8 @@ enum kern_feature_id {
FEAT_PERF_LINK,
/* BTF_KIND_DECL_TAG support */
FEAT_BTF_DECL_TAG,
+ /* BTF_KIND_TYPE_TAG support */
+ FEAT_BTF_TYPE_TAG,
__FEAT_CNT,
};
@@ -2076,6 +2078,7 @@ static const char *__btf_kind_str(__u16 kind)
case BTF_KIND_DATASEC: return "datasec";
case BTF_KIND_FLOAT: return "float";
case BTF_KIND_DECL_TAG: return "decl_tag";
+ case BTF_KIND_TYPE_TAG: return "type_tag";
default: return "unknown";
}
}
@@ -2588,8 +2591,10 @@ static bool btf_needs_sanitization(struct bpf_object *obj)
bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT);
bool has_func = kernel_supports(obj, FEAT_BTF_FUNC);
bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG);
+ bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG);
- return !has_func || !has_datasec || !has_func_global || !has_float || !has_decl_tag;
+ return !has_func || !has_datasec || !has_func_global || !has_float ||
+ !has_decl_tag || !has_type_tag;
}
static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
@@ -2599,6 +2604,7 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT);
bool has_func = kernel_supports(obj, FEAT_BTF_FUNC);
bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG);
+ bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG);
struct btf_type *t;
int i, j, vlen;
@@ -2657,6 +2663,10 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
*/
t->name_off = 0;
t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 0);
+ } else if (!has_type_tag && btf_is_type_tag(t)) {
+ /* replace TYPE_TAG with a CONST */
+ t->name_off = 0;
+ t->info = BTF_INFO_ENC(BTF_KIND_CONST, 0, 0);
}
}
}
@@ -4460,6 +4470,22 @@ static int probe_kern_btf_decl_tag(void)
strs, sizeof(strs)));
}
+static int probe_kern_btf_type_tag(void)
+{
+ static const char strs[] = "\0tag";
+ __u32 types[] = {
+ /* int */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
+ /* attr */
+ BTF_TYPE_TYPE_TAG_ENC(1, 1), /* [2] */
+ /* ptr */
+ BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2), /* [3] */
+ };
+
+ return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+ strs, sizeof(strs)));
+}
+
static int probe_kern_array_mmap(void)
{
struct bpf_create_map_attr attr = {
@@ -4657,6 +4683,9 @@ static struct kern_feature_desc {
[FEAT_BTF_DECL_TAG] = {
"BTF_KIND_DECL_TAG support", probe_kern_btf_decl_tag,
},
+ [FEAT_BTF_TYPE_TAG] = {
+ "BTF_KIND_TYPE_TAG support", probe_kern_btf_type_tag,
+ },
};
static bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index b895861a13c0..0126d924674f 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -401,6 +401,7 @@ LIBBPF_0.6.0 {
bpf_program__insns;
btf__add_btf;
btf__add_decl_tag;
+ btf__add_type_tag;
btf__raw_data;
btf__type_cnt;
} LIBBPF_0.5.0;
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 2d873c962f99..5490fa98c0a6 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -73,6 +73,8 @@
BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
#define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
+#define BTF_TYPE_TYPE_TAG_ENC(value, type) \
+ BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)
#ifndef likely
#define likely(x) __builtin_expect(!!(x), 1)
--
2.30.2
