Commit dffbbdc2 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

libbpf: Add enum64 parsing and new enum64 public API 



Add enum64 parsing support and two new enum64 public APIs:
  btf__add_enum64
  btf__add_enum64_value

Also add support of signedness for BTF_KIND_ENUM. The
BTF_KIND_ENUM API signatures are not changed. The signedness
will be changed from unsigned to signed if btf__add_enum_value()
finds any negative values.

Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220607062621.3719391-1-yhs@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 8479aa75

tools/lib/bpf/btf.c

+103 −0
Original line number Diff line number Diff line
@@ -305,6 +305,8 @@ static int btf_type_size(const struct btf_type *t) 
		return base_size + sizeof(__u32);

	case BTF_KIND_ENUM:

		return base_size + vlen * sizeof(struct btf_enum);

	case BTF_KIND_ENUM64:

		return base_size + vlen * sizeof(struct btf_enum64);

	case BTF_KIND_ARRAY:

		return base_size + sizeof(struct btf_array);

	case BTF_KIND_STRUCT:
@@ -334,6 +336,7 @@ static void btf_bswap_type_base(struct btf_type *t) 
static int btf_bswap_type_rest(struct btf_type *t)

{

	struct btf_var_secinfo *v;

	struct btf_enum64 *e64;

	struct btf_member *m;

	struct btf_array *a;

	struct btf_param *p;
@@ -361,6 +364,13 @@ static int btf_bswap_type_rest(struct btf_type *t) 
			e->val = bswap_32(e->val);

		}

		return 0;

	case BTF_KIND_ENUM64:

		for (i = 0, e64 = btf_enum64(t); i < vlen; i++, e64++) {

			e64->name_off = bswap_32(e64->name_off);

			e64->val_lo32 = bswap_32(e64->val_lo32);

			e64->val_hi32 = bswap_32(e64->val_hi32);

		}

		return 0;

	case BTF_KIND_ARRAY:

		a = btf_array(t);

		a->type = bswap_32(a->type);
@@ -611,6 +621,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) 
		case BTF_KIND_STRUCT:

		case BTF_KIND_UNION:

		case BTF_KIND_ENUM:

		case BTF_KIND_ENUM64:

		case BTF_KIND_DATASEC:

		case BTF_KIND_FLOAT:

			size = t->size;
@@ -658,6 +669,7 @@ int btf__align_of(const struct btf *btf, __u32 id) 
	switch (kind) {

	case BTF_KIND_INT:

	case BTF_KIND_ENUM:

	case BTF_KIND_ENUM64:

	case BTF_KIND_FLOAT:

		return min(btf_ptr_sz(btf), (size_t)t->size);

	case BTF_KIND_PTR:
@@ -2176,6 +2188,10 @@ static int btf_add_enum_common(struct btf *btf, const char *name, __u32 byte_sz, 
 */

int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz)

{

	/*

	 * set the signedness to be unsigned, it will change to signed

	 * if any later enumerator is negative.

	 */

	return btf_add_enum_common(btf, name, byte_sz, false, BTF_KIND_ENUM);

}
@@ -2226,6 +2242,82 @@ int btf__add_enum_value(struct btf *btf, const char *name, __s64 value) 
	t = btf_last_type(btf);

	btf_type_inc_vlen(t);



	/* if negative value, set signedness to signed */

	if (value < 0)

		t->info = btf_type_info(btf_kind(t), btf_vlen(t), true);



	btf->hdr->type_len += sz;

	btf->hdr->str_off += sz;

	return 0;

}



/*

 * Append new BTF_KIND_ENUM64 type with:

 *   - *name* - name of the enum, can be NULL or empty for anonymous enums;

 *   - *byte_sz* - size of the enum, in bytes.

 *   - *is_signed* - whether the enum values are signed or not;

 *

 * Enum initially has no enum values in it (and corresponds to enum forward

 * declaration). Enumerator values can be added by btf__add_enum64_value()

 * immediately after btf__add_enum64() succeeds.

 *

 * Returns:

 *   - >0, type ID of newly added BTF type;

 *   - <0, on error.

 */

int btf__add_enum64(struct btf *btf, const char *name, __u32 byte_sz,

		    bool is_signed)

{

	return btf_add_enum_common(btf, name, byte_sz, is_signed,

				   BTF_KIND_ENUM64);

}



/*

 * Append new enum value for the current ENUM64 type with:

 *   - *name* - name of the enumerator value, can't be NULL or empty;

 *   - *value* - integer value corresponding to enum value *name*;

 * Returns:

 *   -  0, on success;

 *   - <0, on error.

 */

int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value)

{

	struct btf_enum64 *v;

	struct btf_type *t;

	int sz, name_off;



	/* last type should be BTF_KIND_ENUM64 */

	if (btf->nr_types == 0)

		return libbpf_err(-EINVAL);

	t = btf_last_type(btf);

	if (!btf_is_enum64(t))

		return libbpf_err(-EINVAL);



	/* non-empty name */

	if (!name || !name[0])

		return libbpf_err(-EINVAL);



	/* decompose and invalidate raw data */

	if (btf_ensure_modifiable(btf))

		return libbpf_err(-ENOMEM);



	sz = sizeof(struct btf_enum64);

	v = btf_add_type_mem(btf, sz);

	if (!v)

		return libbpf_err(-ENOMEM);



	name_off = btf__add_str(btf, name);

	if (name_off < 0)

		return name_off;



	v->name_off = name_off;

	v->val_lo32 = (__u32)value;

	v->val_hi32 = value >> 32;



	/* update parent type's vlen */

	t = btf_last_type(btf);

	btf_type_inc_vlen(t);



	btf->hdr->type_len += sz;

	btf->hdr->str_off += sz;

	return 0;
@@ -4737,6 +4829,7 @@ int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ct 
	case BTF_KIND_INT:

	case BTF_KIND_FLOAT:

	case BTF_KIND_ENUM:

	case BTF_KIND_ENUM64:

		return 0;



	case BTF_KIND_FWD:
@@ -4831,6 +4924,16 @@ int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ct 
		}

		break;

	}

	case BTF_KIND_ENUM64: {

		struct btf_enum64 *m = btf_enum64(t);



		for (i = 0, n = btf_vlen(t); i < n; i++, m++) {

			err = visit(&m->name_off, ctx);

			if (err)

				return err;

		}

		break;

	}

	case BTF_KIND_FUNC_PROTO: {

		struct btf_param *m = btf_params(t);

tools/lib/bpf/btf.h

+12 −0
Original line number Diff line number Diff line
@@ -215,6 +215,8 @@ LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_ 
/* enum construction APIs */

LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz);

LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value);

LIBBPF_API int btf__add_enum64(struct btf *btf, const char *name, __u32 bytes_sz, bool is_signed);

LIBBPF_API int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value);



enum btf_fwd_kind {

	BTF_FWD_STRUCT = 0,
@@ -454,6 +456,11 @@ static inline bool btf_is_enum(const struct btf_type *t) 
	return btf_kind(t) == BTF_KIND_ENUM;

}



static inline bool btf_is_enum64(const struct btf_type *t)

{

	return btf_kind(t) == BTF_KIND_ENUM64;

}



static inline bool btf_is_fwd(const struct btf_type *t)

{

	return btf_kind(t) == BTF_KIND_FWD;
@@ -549,6 +556,11 @@ static inline struct btf_enum *btf_enum(const struct btf_type *t) 
	return (struct btf_enum *)(t + 1);

}



static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)

{

	return (struct btf_enum64 *)(t + 1);

}



static inline struct btf_member *btf_members(const struct btf_type *t)

{

	return (struct btf_member *)(t + 1);

tools/lib/bpf/libbpf.map

+2 −0
Original line number Diff line number Diff line
@@ -462,6 +462,8 @@ LIBBPF_0.8.0 { 


LIBBPF_1.0.0 {

	global:

		btf__add_enum64;

		btf__add_enum64_value;

		libbpf_bpf_attach_type_str;

		libbpf_bpf_link_type_str;

		libbpf_bpf_map_type_str;