@@ -184,6 +184,16 @@ enum bpf_enum_value_kind {
#define bpf_core_type_exists(type) \
__builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_EXISTS)
+/*
+ * Convenience macro to check that provided named type
+ * (struct/union/enum/typedef) "matches" that in a target kernel.
+ * Returns:
+ * 1, if the type matches in the target kernel's BTF;
+ * 0, if the type does not match any in the target kernel
+ */
+#define bpf_core_type_matches(type) \
+ __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_MATCHES)
+
/*
* Convenience macro to get the byte size of a provided named type
* (struct/union/enum/typedef) in a target kernel.
@@ -5735,6 +5735,12 @@ int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id, 32);
}
+int bpf_core_types_match(const struct btf *local_btf, __u32 local_id,
+ const struct btf *targ_btf, __u32 targ_id)
+{
+ return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false, 32);
+}
+
static size_t bpf_core_hash_fn(const void *key, void *ctx)
{
return (size_t)key;
@@ -95,6 +95,7 @@ static const char *core_relo_kind_str(enum bpf_core_relo_kind kind)
case BPF_CORE_TYPE_ID_LOCAL: return "local_type_id";
case BPF_CORE_TYPE_ID_TARGET: return "target_type_id";
case BPF_CORE_TYPE_EXISTS: return "type_exists";
+ case BPF_CORE_TYPE_MATCHES: return "type_matches";
case BPF_CORE_TYPE_SIZE: return "type_size";
case BPF_CORE_ENUMVAL_EXISTS: return "enumval_exists";
case BPF_CORE_ENUMVAL_VALUE: return "enumval_value";
@@ -123,6 +124,7 @@ static bool core_relo_is_type_based(enum bpf_core_relo_kind kind)
case BPF_CORE_TYPE_ID_LOCAL:
case BPF_CORE_TYPE_ID_TARGET:
case BPF_CORE_TYPE_EXISTS:
+ case BPF_CORE_TYPE_MATCHES:
case BPF_CORE_TYPE_SIZE:
return true;
default:
@@ -251,7 +253,7 @@ int __bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
* - field 'a' access (corresponds to '2' in low-level spec);
* - array element #3 access (corresponds to '3' in low-level spec).
*
- * Type-based relocations (TYPE_EXISTS/TYPE_SIZE,
+ * Type-based relocations (TYPE_EXISTS/TYPE_MATCHES/TYPE_SIZE,
* TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their
* spec and raw_spec are kept empty.
*
@@ -568,9 +570,14 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
targ_spec->relo_kind = local_spec->relo_kind;
if (core_relo_is_type_based(local_spec->relo_kind)) {
- return bpf_core_types_are_compat(local_spec->btf,
- local_spec->root_type_id,
- targ_btf, targ_id);
+ if (local_spec->relo_kind == BPF_CORE_TYPE_MATCHES)
+ return bpf_core_types_match(local_spec->btf,
+ local_spec->root_type_id,
+ targ_btf, targ_id);
+ else
+ return bpf_core_types_are_compat(local_spec->btf,
+ local_spec->root_type_id,
+ targ_btf, targ_id);
}
local_acc = &local_spec->spec[0];
@@ -819,6 +826,7 @@ static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo,
*validate = false;
break;
case BPF_CORE_TYPE_EXISTS:
+ case BPF_CORE_TYPE_MATCHES:
*val = 1;
break;
case BPF_CORE_TYPE_SIZE:
@@ -74,6 +74,8 @@ int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
const struct btf *targ_btf, __u32 targ_id);
int __bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf,
__u32 targ_id, bool behind_ptr, int level);
+int bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf,
+ __u32 targ_id);
size_t bpf_core_essential_name_len(const char *name);
This patch finalizes support for the proposed type match relation in libbpf by hooking it up to the TYPE_MATCH relocation. For this relocation to be handled correctly by LLVM we have D126838 (https://reviews.llvm.org/D126838). The main functionality is present behind the newly introduced bpf_core_type_matches macro (similar to bpf_core_type_exists). This macro can be used to check whether a local type has a "match" in a target BTF. Signed-off-by: Daniel Müller <deso@posteo.net> --- tools/lib/bpf/bpf_core_read.h | 10 ++++++++++ tools/lib/bpf/libbpf.c | 6 ++++++ tools/lib/bpf/relo_core.c | 16 ++++++++++++---- tools/lib/bpf/relo_core.h | 2 ++ 4 files changed, 30 insertions(+), 4 deletions(-)