Merge branch 'libbpf-field-existence'

Andrii Nakryiko says:

====================
This patch set generalizes libbpf's CO-RE relocation support. In addition to
existing field's byte offset relocation, libbpf now supports field existence
relocations, which are emitted by Clang when using
__builtin_preserve_field_info(<field>, BPF_FIELD_EXISTS). A convenience
bpf_core_field_exists() macro is added to bpf_core_read.h BPF-side header,
along the bpf_field_info_kind enum containing currently supported types of
field information libbpf supports. This list will grow as libbpf gains support
for other relo kinds.

This patch set upgrades the format of .BTF.ext's relocation record to match
latest Clang's format (12 -> 16 bytes). This is not a breaking change, as the
previous format hasn't been released yet as part of official Clang version
release.

v1->v2:
- unify bpf_field_info_kind enum and naming changes (Alexei);
- added bpf_core_field_exists() to bpf_core_read.h.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 8 insertions, 8 deletions

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 1aa189a9112a5..3eae8d1addfaf 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -888,14 +888,14 @@ static int btf_ext_setup_line_info(struct btf_ext *btf_ext)
 	return btf_ext_setup_info(btf_ext, &param);
 }
 
-static int btf_ext_setup_offset_reloc(struct btf_ext *btf_ext)
+static int btf_ext_setup_field_reloc(struct btf_ext *btf_ext)
 {
 	struct btf_ext_sec_setup_param param = {
-		.off = btf_ext->hdr->offset_reloc_off,
-		.len = btf_ext->hdr->offset_reloc_len,
-		.min_rec_size = sizeof(struct bpf_offset_reloc),
-		.ext_info = &btf_ext->offset_reloc_info,
-		.desc = "offset_reloc",
+		.off = btf_ext->hdr->field_reloc_off,
+		.len = btf_ext->hdr->field_reloc_len,
+		.min_rec_size = sizeof(struct bpf_field_reloc),
+		.ext_info = &btf_ext->field_reloc_info,
+		.desc = "field_reloc",
 	};
 
 	return btf_ext_setup_info(btf_ext, &param);
@@ -975,9 +975,9 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size)
 		goto done;
 
 	if (btf_ext->hdr->hdr_len <
-	    offsetofend(struct btf_ext_header, offset_reloc_len))
+	    offsetofend(struct btf_ext_header, field_reloc_len))
 		goto done;
-	err = btf_ext_setup_offset_reloc(btf_ext);
+	err = btf_ext_setup_field_reloc(btf_ext);
 	if (err)
 		goto done;