diff mbox series

[v2,bpf-next,3/9] libbpf: use kind layout to compute an unknown kind size

Message ID 20230616171728.530116-4-alan.maguire@oracle.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series bpf: support BTF kind layout info, CRCs | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers success CCed 12 of 12 maintainers
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns WARNING: line length of 87 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
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Commit Message

Alan Maguire June 16, 2023, 5:17 p.m. UTC 
This allows BTF parsing to proceed even if we do not know the
kind.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
---
 tools/lib/bpf/btf.c | 41 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 34 insertions(+), 7 deletions(-)

Comments

Andrii Nakryiko June 22, 2023, 10:03 p.m. UTC | #1 
On Fri, Jun 16, 2023 at 10:18 AM Alan Maguire <alan.maguire@oracle.com> wrote:
>
> This allows BTF parsing to proceed even if we do not know the
> kind.
>
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> ---
>  tools/lib/bpf/btf.c | 41 ++++++++++++++++++++++++++++++++++-------
>  1 file changed, 34 insertions(+), 7 deletions(-)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index f9f919fdc728..457997c2a43c 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -327,7 +327,35 @@ static int btf_parse_kind_layout_sec(struct btf *btf)
>         return 0;
>  }
>
> -static int btf_type_size(const struct btf_type *t)
> +/* for unknown kinds, consult kind layout. */
> +static int btf_type_size_unknown(const struct btf *btf, const struct btf_type *t)
> +{
> +       int size = sizeof(struct btf_type);
> +       struct btf_kind_layout *k = NULL;
> +       __u16 vlen = btf_vlen(t);
> +       __u8 kind = btf_kind(t);
> +
> +       if (btf->kind_layout)
> +               k = &btf->kind_layout[kind];

see my suggestion on the previous patch. Let's make this layout
information mandatory internally and always use it consistently.

simpler code, more testing for this new code path


> +
> +       if (!k || (void *)k > ((void *)btf->kind_layout + btf->hdr->kind_layout_len)) {
> +               pr_debug("Unsupported BTF_KIND: %u\n", btf_kind(t));
> +               return -EINVAL;
> +       }
> +
> +       if (!(k->flags & BTF_KIND_LAYOUT_OPTIONAL)) {
> +               /* a required kind, and we do not know about it.. */
> +               pr_debug("unknown but required kind: %u\n", kind);
> +               return -EINVAL;
> +       }
> +
> +       size += k->info_sz;
> +       size += vlen * k->elem_sz;
> +
> +       return size;
> +}
> +
> +static int btf_type_size(const struct btf *btf, const struct btf_type *t)
>  {
>         const int base_size = sizeof(struct btf_type);
>         __u16 vlen = btf_vlen(t);
> @@ -363,8 +391,7 @@ static int btf_type_size(const struct btf_type *t)
>         case BTF_KIND_DECL_TAG:
>                 return base_size + sizeof(struct btf_decl_tag);
>         default:
> -               pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
> -               return -EINVAL;
> +               return btf_type_size_unknown(btf, t);
>         }
>  }
>
> @@ -463,7 +490,7 @@ static int btf_parse_type_sec(struct btf *btf)
>                 if (btf->swapped_endian)
>                         btf_bswap_type_base(next_type);
>
> -               type_size = btf_type_size(next_type);
> +               type_size = btf_type_size(btf, next_type);
>                 if (type_size < 0)
>                         return type_size;
>                 if (next_type + type_size > end_type) {
> @@ -1672,7 +1699,7 @@ int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t
>         struct btf_type *t;
>         int sz, err;
>
> -       sz = btf_type_size(src_type);
> +       sz = btf_type_size(src_btf, src_type);
>         if (sz < 0)
>                 return libbpf_err(sz);
>
> @@ -1753,7 +1780,7 @@ int btf__add_btf(struct btf *btf, const struct btf *src_btf)
>         memcpy(t, src_btf->types_data, data_sz);
>
>         for (i = 0; i < cnt; i++) {
> -               sz = btf_type_size(t);
> +               sz = btf_type_size(src_btf, t);
>                 if (sz < 0) {
>                         /* unlikely, has to be corrupted src_btf */
>                         err = sz;
> @@ -4749,7 +4776,7 @@ static int btf_dedup_compact_types(struct btf_dedup *d)
>                         continue;
>
>                 t = btf__type_by_id(d->btf, id);
> -               len = btf_type_size(t);
> +               len = btf_type_size(d->btf, t);
>                 if (len < 0)
>                         return len;
>
> --
> 2.39.3
>
diff mbox series

Patch

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index f9f919fdc728..457997c2a43c 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -327,7 +327,35 @@  static int btf_parse_kind_layout_sec(struct btf *btf)
 	return 0;
 }
 
-static int btf_type_size(const struct btf_type *t)
+/* for unknown kinds, consult kind layout. */
+static int btf_type_size_unknown(const struct btf *btf, const struct btf_type *t)
+{
+	int size = sizeof(struct btf_type);
+	struct btf_kind_layout *k = NULL;
+	__u16 vlen = btf_vlen(t);
+	__u8 kind = btf_kind(t);
+
+	if (btf->kind_layout)
+		k = &btf->kind_layout[kind];
+
+	if (!k || (void *)k > ((void *)btf->kind_layout + btf->hdr->kind_layout_len)) {
+		pr_debug("Unsupported BTF_KIND: %u\n", btf_kind(t));
+		return -EINVAL;
+	}
+
+	if (!(k->flags & BTF_KIND_LAYOUT_OPTIONAL)) {
+		/* a required kind, and we do not know about it.. */
+		pr_debug("unknown but required kind: %u\n", kind);
+		return -EINVAL;
+	}
+
+	size += k->info_sz;
+	size += vlen * k->elem_sz;
+
+	return size;
+}
+
+static int btf_type_size(const struct btf *btf, const struct btf_type *t)
 {
 	const int base_size = sizeof(struct btf_type);
 	__u16 vlen = btf_vlen(t);
@@ -363,8 +391,7 @@  static int btf_type_size(const struct btf_type *t)
 	case BTF_KIND_DECL_TAG:
 		return base_size + sizeof(struct btf_decl_tag);
 	default:
-		pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
-		return -EINVAL;
+		return btf_type_size_unknown(btf, t);
 	}
 }
 
@@ -463,7 +490,7 @@  static int btf_parse_type_sec(struct btf *btf)
 		if (btf->swapped_endian)
 			btf_bswap_type_base(next_type);
 
-		type_size = btf_type_size(next_type);
+		type_size = btf_type_size(btf, next_type);
 		if (type_size < 0)
 			return type_size;
 		if (next_type + type_size > end_type) {
@@ -1672,7 +1699,7 @@  int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t
 	struct btf_type *t;
 	int sz, err;
 
-	sz = btf_type_size(src_type);
+	sz = btf_type_size(src_btf, src_type);
 	if (sz < 0)
 		return libbpf_err(sz);
 
@@ -1753,7 +1780,7 @@  int btf__add_btf(struct btf *btf, const struct btf *src_btf)
 	memcpy(t, src_btf->types_data, data_sz);
 
 	for (i = 0; i < cnt; i++) {
-		sz = btf_type_size(t);
+		sz = btf_type_size(src_btf, t);
 		if (sz < 0) {
 			/* unlikely, has to be corrupted src_btf */
 			err = sz;
@@ -4749,7 +4776,7 @@  static int btf_dedup_compact_types(struct btf_dedup *d)
 			continue;
 
 		t = btf__type_by_id(d->btf, id);
-		len = btf_type_size(t);
+		len = btf_type_size(d->btf, t);
 		if (len < 0)
 			return len;