Add BTF_KIND_TAG support for parsing and dedup.
Also added sanitization for BTF_KIND_TAG. If BTF_KIND_TAG is not
supported in the kernel, sanitize it to INTs.
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
tools/lib/bpf/btf.c | 68 +++++++++++++++++++++++++++++++++
tools/lib/bpf/btf.h | 15 ++++++++
tools/lib/bpf/btf_dump.c | 3 ++
tools/lib/bpf/libbpf.c | 31 +++++++++++++--
tools/lib/bpf/libbpf.map | 2 +
tools/lib/bpf/libbpf_internal.h | 2 +
6 files changed, 118 insertions(+), 3 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 7cb6ebf1be37..6ad63e4d418a 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -304,6 +304,8 @@ static int btf_type_size(const struct btf_type *t)
return base_size + sizeof(struct btf_var);
case BTF_KIND_DATASEC:
return base_size + vlen * sizeof(struct btf_var_secinfo);
+ case BTF_KIND_TAG:
+ return base_size + sizeof(struct btf_tag);
default:
pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
return -EINVAL;
@@ -376,6 +378,9 @@ static int btf_bswap_type_rest(struct btf_type *t)
v->size = bswap_32(v->size);
}
return 0;
+ case BTF_KIND_TAG:
+ btf_tag(t)->component_idx = bswap_32(btf_tag(t)->component_idx);
+ return 0;
default:
pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
return -EINVAL;
@@ -586,6 +591,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
case BTF_KIND_VAR:
+ case BTF_KIND_TAG:
type_id = t->type;
break;
case BTF_KIND_ARRAY:
@@ -2440,6 +2446,48 @@ int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __
return 0;
}
+/*
+ * Append new BTF_KIND_TAG type with:
+ * - *value* - non-empty/non-NULL string;
+ * - *ref_type_id* - referenced type ID, it might not exist yet;
+ * - *component_idx* - -1 for tagging reference type, otherwise struct/union
+ * member or function argument index;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_tag(struct btf *btf, const char *value, int ref_type_id,
+ int component_idx)
+{
+ struct btf_type *t;
+ int sz, value_off;
+
+ if (!value || !value[0] || component_idx < -1)
+ return libbpf_err(-EINVAL);
+
+ if (validate_type_id(ref_type_id))
+ return libbpf_err(-EINVAL);
+
+ if (btf_ensure_modifiable(btf))
+ return libbpf_err(-ENOMEM);
+
+ sz = sizeof(struct btf_type) + sizeof(struct btf_tag);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return libbpf_err(-ENOMEM);
+
+ value_off = btf__add_str(btf, value);
+ if (value_off < 0)
+ return value_off;
+
+ t->name_off = value_off;
+ t->info = btf_type_info(BTF_KIND_TAG, 0, false);
+ t->type = ref_type_id;
+ btf_tag(t)->component_idx = component_idx;
+
+ return btf_commit_type(btf, sz);
+}
+
struct btf_ext_sec_setup_param {
__u32 off;
__u32 len;
@@ -3535,6 +3583,7 @@ static int btf_dedup_prep(struct btf_dedup *d)
h = btf_hash_common(t);
break;
case BTF_KIND_INT:
+ case BTF_KIND_TAG:
h = btf_hash_int_tag(t);
break;
case BTF_KIND_ENUM:
@@ -3590,6 +3639,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
case BTF_KIND_FUNC_PROTO:
case BTF_KIND_VAR:
case BTF_KIND_DATASEC:
+ case BTF_KIND_TAG:
return 0;
case BTF_KIND_INT:
@@ -4210,6 +4260,23 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
}
break;
+ case BTF_KIND_TAG:
+ ref_type_id = btf_dedup_ref_type(d, t->type);
+ if (ref_type_id < 0)
+ return ref_type_id;
+ t->type = ref_type_id;
+
+ h = btf_hash_int_tag(t);
+ for_each_dedup_cand(d, hash_entry, h) {
+ cand_id = (__u32)(long)hash_entry->value;
+ cand = btf_type_by_id(d->btf, cand_id);
+ if (btf_equal_int_tag(t, cand)) {
+ new_id = cand_id;
+ break;
+ }
+ }
+ break;
+
case BTF_KIND_ARRAY: {
struct btf_array *info = btf_array(t);
@@ -4482,6 +4549,7 @@ int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ct
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
case BTF_KIND_VAR:
+ case BTF_KIND_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 f2e2fab950b7..659ea8a2769b 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -143,6 +143,10 @@ LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz
LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id,
__u32 offset, __u32 byte_sz);
+/* tag construction API */
+LIBBPF_API int btf__add_tag(struct btf *btf, const char *value, int ref_type_id,
+ int component_idx);
+
struct btf_dedup_opts {
unsigned int dedup_table_size;
bool dont_resolve_fwds;
@@ -330,6 +334,11 @@ static inline bool btf_is_float(const struct btf_type *t)
return btf_kind(t) == BTF_KIND_FLOAT;
}
+static inline bool btf_is_tag(const struct btf_type *t)
+{
+ return btf_kind(t) == BTF_KIND_TAG;
+}
+
static inline __u8 btf_int_encoding(const struct btf_type *t)
{
return BTF_INT_ENCODING(*(__u32 *)(t + 1));
@@ -398,6 +407,12 @@ btf_var_secinfos(const struct btf_type *t)
return (struct btf_var_secinfo *)(t + 1);
}
+struct btf_tag;
+static inline struct btf_tag *btf_tag(const struct btf_type *t)
+{
+ return (struct btf_tag *)(t + 1);
+}
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index e4b483f15fb9..ad6df97295ae 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -316,6 +316,7 @@ static int btf_dump_mark_referenced(struct btf_dump *d)
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
case BTF_KIND_VAR:
+ case BTF_KIND_TAG:
d->type_states[t->type].referenced = 1;
break;
@@ -583,6 +584,7 @@ static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr)
case BTF_KIND_FUNC:
case BTF_KIND_VAR:
case BTF_KIND_DATASEC:
+ case BTF_KIND_TAG:
d->type_states[id].order_state = ORDERED;
return 0;
@@ -2215,6 +2217,7 @@ static int btf_dump_dump_type_data(struct btf_dump *d,
case BTF_KIND_FWD:
case BTF_KIND_FUNC:
case BTF_KIND_FUNC_PROTO:
+ case BTF_KIND_TAG:
err = btf_dump_unsupported_data(d, t, id);
break;
case BTF_KIND_INT:
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6ecfdc1fa7ba..b159f9b51b7f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -195,6 +195,8 @@ enum kern_feature_id {
FEAT_BTF_FLOAT,
/* BPF perf link support */
FEAT_PERF_LINK,
+ /* BTF_KIND_TAG support */
+ FEAT_BTF_TAG,
__FEAT_CNT,
};
@@ -1987,6 +1989,7 @@ static const char *__btf_kind_str(__u16 kind)
case BTF_KIND_VAR: return "var";
case BTF_KIND_DATASEC: return "datasec";
case BTF_KIND_FLOAT: return "float";
+ case BTF_KIND_TAG: return "tag";
default: return "unknown";
}
}
@@ -2486,8 +2489,9 @@ static bool btf_needs_sanitization(struct bpf_object *obj)
bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC);
bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT);
bool has_func = kernel_supports(obj, FEAT_BTF_FUNC);
+ bool has_tag = kernel_supports(obj, FEAT_BTF_TAG);
- return !has_func || !has_datasec || !has_func_global || !has_float;
+ return !has_func || !has_datasec || !has_func_global || !has_float || !has_tag;
}
static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
@@ -2496,14 +2500,15 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC);
bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT);
bool has_func = kernel_supports(obj, FEAT_BTF_FUNC);
+ bool has_tag = kernel_supports(obj, FEAT_BTF_TAG);
struct btf_type *t;
int i, j, vlen;
for (i = 1; i <= btf__get_nr_types(btf); i++) {
t = (struct btf_type *)btf__type_by_id(btf, i);
- if (!has_datasec && btf_is_var(t)) {
- /* replace VAR with INT */
+ if ((!has_datasec && btf_is_var(t)) || (!has_tag && btf_is_tag(t))) {
+ /* replace VAR/TAG with INT */
t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
/*
* using size = 1 is the safest choice, 4 will be too
@@ -4213,6 +4218,23 @@ static int probe_kern_btf_float(void)
strs, sizeof(strs)));
}
+static int probe_kern_btf_tag(void)
+{
+ static const char strs[] = "\0tag";
+ __u32 types[] = {
+ /* int */
+ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
+ /* VAR x */ /* [2] */
+ BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
+ BTF_VAR_STATIC,
+ /* attr */
+ BTF_TYPE_TAG_ENC(1, 2, -1),
+ };
+
+ 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 = {
@@ -4429,6 +4451,9 @@ static struct kern_feature_desc {
[FEAT_PERF_LINK] = {
"BPF perf link support", probe_perf_link,
},
+ [FEAT_BTF_TAG] = {
+ "BTF_KIND_TAG support", probe_kern_btf_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 78ea62c9346f..9e649cf9e771 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -388,4 +388,6 @@ LIBBPF_0.5.0 {
} LIBBPF_0.4.0;
LIBBPF_0.6.0 {
+ global:
+ btf__add_tag;
} LIBBPF_0.5.0;
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 4f6ff5c23695..ceb0c98979bc 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -69,6 +69,8 @@
#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
#define BTF_TYPE_FLOAT_ENC(name, sz) \
BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
+#define BTF_TYPE_TAG_ENC(value, type, component_idx) \
+ BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TAG, 0, 0), type), (component_idx)
#ifndef likely
#define likely(x) __builtin_expect(!!(x), 1)
--
2.30.2
