From b1828f0b04828aa8cccadf00a702f459caefeed9 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Fri, 26 Feb 2021 21:22:52 +0100 Subject: bpf: Add BTF_KIND_FLOAT support 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 Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20210226202256.116518-7-iii@linux.ibm.com --- kernel/bpf/btf.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 81 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 16e8148a28e2..c914d68f3bf8 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -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, -- cgit v1.2.3