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bpf: Add BTF_KIND_FLOAT support

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On the kernel side, introduce a new btf_kind_operations. It is
similar to that of BTF_KIND_INT, however, it does not need to
handle encodings and bit offsets. Do not implement printing, since
the kernel does not know how to format floating-point values.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210226202256.116518-7-iii@linux.ibm.com
This commit is contained in:
Ilya Leoshkevich 2021-02-26 21:22:52 +01:00 committed by Alexei Starovoitov
parent eea154a852
commit b1828f0b04
1 changed files with 81 additions and 2 deletions
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83
kernel/bpf/btf.c
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@ -173,7 +173,7 @@
#define BITS_ROUNDUP_BYTES(bits) \
(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
#define BTF_INFO_MASK 0x8f00ffff
#define BTF_INFO_MASK 0x9f00ffff
#define BTF_INT_MASK 0x0fffffff
#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
@ -280,6 +280,7 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = {
[BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
[BTF_KIND_VAR] = "VAR",
[BTF_KIND_DATASEC] = "DATASEC",
[BTF_KIND_FLOAT] = "FLOAT",
};
static const char *btf_type_str(const struct btf_type *t)
@ -574,6 +575,7 @@ static bool btf_type_has_size(const struct btf_type *t)
case BTF_KIND_UNION:
case BTF_KIND_ENUM:
case BTF_KIND_DATASEC:
case BTF_KIND_FLOAT:
return true;
}
@ -1704,6 +1706,7 @@ __btf_resolve_size(const struct btf *btf, const struct btf_type *type,
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
case BTF_KIND_ENUM:
case BTF_KIND_FLOAT:
size = type->size;
goto resolved;
@ -1849,7 +1852,7 @@ static int btf_df_check_kflag_member(struct btf_verifier_env *env,
return -EINVAL;
}
/* Used for ptr, array and struct/union type members.
/* Used for ptr, array struct/union and float type members.
* int, enum and modifier types have their specific callback functions.
*/
static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
@ -3675,6 +3678,81 @@ static const struct btf_kind_operations datasec_ops = {
.show = btf_datasec_show,
};
static s32 btf_float_check_meta(struct btf_verifier_env *env,
const struct btf_type *t,
u32 meta_left)
{
if (btf_type_vlen(t)) {
btf_verifier_log_type(env, t, "vlen != 0");
return -EINVAL;
}
if (btf_type_kflag(t)) {
btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
return -EINVAL;
}
if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
t->size != 16) {
btf_verifier_log_type(env, t, "Invalid type_size");
return -EINVAL;
}
btf_verifier_log_type(env, t, NULL);
return 0;
}
static int btf_float_check_member(struct btf_verifier_env *env,
const struct btf_type *struct_type,
const struct btf_member *member,
const struct btf_type *member_type)
{
u64 start_offset_bytes;
u64 end_offset_bytes;
u64 misalign_bits;
u64 align_bytes;
u64 align_bits;
/* Different architectures have different alignment requirements, so
* here we check only for the reasonable minimum. This way we ensure
* that types after CO-RE can pass the kernel BTF verifier.
*/
align_bytes = min_t(u64, sizeof(void *), member_type->size);
align_bits = align_bytes * BITS_PER_BYTE;
div64_u64_rem(member->offset, align_bits, &misalign_bits);
if (misalign_bits) {
btf_verifier_log_member(env, struct_type, member,
"Member is not properly aligned");
return -EINVAL;
}
start_offset_bytes = member->offset / BITS_PER_BYTE;
end_offset_bytes = start_offset_bytes + member_type->size;
if (end_offset_bytes > struct_type->size) {
btf_verifier_log_member(env, struct_type, member,
"Member exceeds struct_size");
return -EINVAL;
}
return 0;
}
static void btf_float_log(struct btf_verifier_env *env,
const struct btf_type *t)
{
btf_verifier_log(env, "size=%u", t->size);
}
static const struct btf_kind_operations float_ops = {
.check_meta = btf_float_check_meta,
.resolve = btf_df_resolve,
.check_member = btf_float_check_member,
.check_kflag_member = btf_generic_check_kflag_member,
.log_details = btf_float_log,
.show = btf_df_show,
};
static int btf_func_proto_check(struct btf_verifier_env *env,
const struct btf_type *t)
{
@ -3808,6 +3886,7 @@ static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
[BTF_KIND_FUNC_PROTO] = &func_proto_ops,
[BTF_KIND_VAR] = &var_ops,
[BTF_KIND_DATASEC] = &datasec_ops,
[BTF_KIND_FLOAT] = &float_ops,
};
static s32 btf_check_meta(struct btf_verifier_env *env,