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
>
