On Mon, Sep 13, 2021 at 8:51 AM Yonghong Song <yhs@xxxxxx> wrote:
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 | 69 +++++++++++++++++++++++++++++++++
tools/lib/bpf/btf.h | 15 +++++++
tools/lib/bpf/btf_dump.c | 3 ++
tools/lib/bpf/libbpf.c | 31 +++++++++++++--
tools/lib/bpf/libbpf.map | 5 +++
tools/lib/bpf/libbpf_internal.h | 2 +
6 files changed, 122 insertions(+), 3 deletions(-)
Just a few small nits.
[...]
@@ -2440,6 +2446,49 @@ 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)
+{
+ bool for_ref_type = false;
leftovers from the previous revision? let's just use 0 for kflag argument below
+ 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, for_ref_type);
+ t->type = ref_type_id;
+ ((struct btf_tag *)(t + 1))->component_idx = component_idx;
nit: btf_tag(t)->component_idx
+
+ return btf_commit_type(btf, sz);
+}
+
struct btf_ext_sec_setup_param {
__u32 off;
__u32 len;
[...]
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8f579c6666b2..4a62ef714562 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_ATTR support */
s/BTF_KIND_ATTR/BTF_KIND_TAG/
+ FEAT_BTF_TAG,
__FEAT_CNT,
};
[...]
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 bbc53bb25f68..9e649cf9e771 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -386,3 +386,8 @@ LIBBPF_0.5.0 {
btf_dump__dump_type_data;
libbpf_set_strict_mode;
} LIBBPF_0.4.0;
+
+LIBBPF_0.6.0 {
+ global:
+ btf__add_tag;
+} LIBBPF_0.5.0;
you'll need a rebase for this due to my patch for libbpf_version.h, sorry
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
