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libbpf: Add enum64 parsing and new enum64 public API

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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: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220607062621.3719391-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song 2022-06-06 23:26:21 -07:00 committed by Alexei Starovoitov
parent 8479aa7522
commit dffbbdc2d9
3 changed files with 117 additions and 0 deletions
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103
tools/lib/bpf/btf.c
View File

@ -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);

12
tools/lib/bpf/btf.h
View File

@ -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);

2
tools/lib/bpf/libbpf.map
View File

@ -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;