Commit 2ef20263 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

libbpf: Add enum64 deduplication support 



Add enum64 deduplication support. BTF_KIND_ENUM64 handling
is very similar to BTF_KIND_ENUM.

Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220607062626.3720166-1-yhs@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent dffbbdc2

tools/lib/bpf/btf.c

+60 −2
Original line number Diff line number Diff line
@@ -3582,7 +3582,7 @@ static bool btf_equal_int_tag(struct btf_type *t1, struct btf_type *t2) 
	return info1 == info2;

}



/* Calculate type signature hash of ENUM. */

/* Calculate type signature hash of ENUM/ENUM64. */

static long btf_hash_enum(struct btf_type *t)

{

	long h;
@@ -3616,9 +3616,31 @@ static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2) 
	return true;

}



static bool btf_equal_enum64(struct btf_type *t1, struct btf_type *t2)

{

	const struct btf_enum64 *m1, *m2;

	__u16 vlen;

	int i;



	if (!btf_equal_common(t1, t2))

		return false;



	vlen = btf_vlen(t1);

	m1 = btf_enum64(t1);

	m2 = btf_enum64(t2);

	for (i = 0; i < vlen; i++) {

		if (m1->name_off != m2->name_off || m1->val_lo32 != m2->val_lo32 ||

		    m1->val_hi32 != m2->val_hi32)

			return false;

		m1++;

		m2++;

	}

	return true;

}



static inline bool btf_is_enum_fwd(struct btf_type *t)

{

	return btf_is_enum(t) && btf_vlen(t) == 0;

	return btf_is_any_enum(t) && btf_vlen(t) == 0;

}



static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2)
@@ -3631,6 +3653,17 @@ static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2) 
	       t1->size == t2->size;

}



static bool btf_compat_enum64(struct btf_type *t1, struct btf_type *t2)

{

	if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))

		return btf_equal_enum64(t1, t2);



	/* ignore vlen when comparing */

	return t1->name_off == t2->name_off &&

	       (t1->info & ~0xffff) == (t2->info & ~0xffff) &&

	       t1->size == t2->size;

}



/*

 * Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs,

 * as referenced type IDs equivalence is established separately during type
@@ -3843,6 +3876,7 @@ static int btf_dedup_prep(struct btf_dedup *d) 
			h = btf_hash_int_decl_tag(t);

			break;

		case BTF_KIND_ENUM:

		case BTF_KIND_ENUM64:

			h = btf_hash_enum(t);

			break;

		case BTF_KIND_STRUCT:
@@ -3932,6 +3966,27 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) 
		}

		break;



	case BTF_KIND_ENUM64:

		h = btf_hash_enum(t);

		for_each_dedup_cand(d, hash_entry, h) {

			cand_id = (__u32)(long)hash_entry->value;

			cand = btf_type_by_id(d->btf, cand_id);

			if (btf_equal_enum64(t, cand)) {

				new_id = cand_id;

				break;

			}

			if (btf_compat_enum64(t, cand)) {

				if (btf_is_enum_fwd(t)) {

					/* resolve fwd to full enum */

					new_id = cand_id;

					break;

				}

				/* resolve canonical enum fwd to full enum */

				d->map[cand_id] = type_id;

			}

		}

		break;



	case BTF_KIND_FWD:

	case BTF_KIND_FLOAT:

		h = btf_hash_common(t);
@@ -4227,6 +4282,9 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, 
	case BTF_KIND_ENUM:

		return btf_compat_enum(cand_type, canon_type);



	case BTF_KIND_ENUM64:

		return btf_compat_enum64(cand_type, canon_type);



	case BTF_KIND_FWD:

	case BTF_KIND_FLOAT:

		return btf_equal_common(cand_type, canon_type);

tools/lib/bpf/btf.h

+5 −0
Original line number Diff line number Diff line
@@ -531,6 +531,11 @@ static inline bool btf_is_type_tag(const struct btf_type *t) 
	return btf_kind(t) == BTF_KIND_TYPE_TAG;

}



static inline bool btf_is_any_enum(const struct btf_type *t)

{

	return btf_is_enum(t) || btf_is_enum64(t);

}



static inline __u8 btf_int_encoding(const struct btf_type *t)

{

	return BTF_INT_ENCODING(*(__u32 *)(t + 1));