selftest/bpf: Add BTF_KIND_FLOAT tests

Test the good variants as well as the potential malformed ones.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210226202256.116518-8-iii@linux.ibm.com

tools/testing/selftests/bpf/btf_helpers.c

@@ -23,6 +23,7 @@ static const char * const btf_kind_str_mapping[] = {
 	[BTF_KIND_FUNC_PROTO]	= "FUNC_PROTO",
 	[BTF_KIND_VAR]		= "VAR",
 	[BTF_KIND_DATASEC]	= "DATASEC",
+	[BTF_KIND_FLOAT]	= "FLOAT",
 };
 
 static const char *btf_kind_str(__u16 kind)
@@ -173,6 +174,9 @@ int fprintf_btf_type_raw(FILE *out, const struct btf *btf, __u32 id)
 		}
 		break;
 	}
+	case BTF_KIND_FLOAT:
+		fprintf(out, " size=%u", t->size);
+		break;
 	default:
 		break;
 	}

tools/testing/selftests/bpf/prog_tests/btf.c

@@ -3531,6 +3531,136 @@ static struct btf_raw_test raw_tests[] = {
 	.max_entries = 1,
 },
 
+{
+	.descr = "float test #1, well-formed",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),
+								/* [1] */
+		BTF_TYPE_FLOAT_ENC(NAME_TBD, 2),		/* [2] */
+		BTF_TYPE_FLOAT_ENC(NAME_TBD, 4),		/* [3] */
+		BTF_TYPE_FLOAT_ENC(NAME_TBD, 8),		/* [4] */
+		BTF_TYPE_FLOAT_ENC(NAME_TBD, 12),		/* [5] */
+		BTF_TYPE_FLOAT_ENC(NAME_TBD, 16),		/* [6] */
+		BTF_STRUCT_ENC(NAME_TBD, 5, 48),		/* [7] */
+		BTF_MEMBER_ENC(NAME_TBD, 2, 0),
+		BTF_MEMBER_ENC(NAME_TBD, 3, 32),
+		BTF_MEMBER_ENC(NAME_TBD, 4, 64),
+		BTF_MEMBER_ENC(NAME_TBD, 5, 128),
+		BTF_MEMBER_ENC(NAME_TBD, 6, 256),
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0_Float16\0float\0double\0_Float80\0long_double"
+		    "\0floats\0a\0b\0c\0d\0e"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "float_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = 48,
+	.key_type_id = 1,
+	.value_type_id = 7,
+	.max_entries = 1,
+},
+{
+	.descr = "float test #2, invalid vlen",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),
+								/* [1] */
+		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 1), 4),
+								/* [2] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0float"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "float_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = 4,
+	.key_type_id = 1,
+	.value_type_id = 2,
+	.max_entries = 1,
+	.btf_load_err = true,
+	.err_str = "vlen != 0",
+},
+{
+	.descr = "float test #3, invalid kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),
+								/* [1] */
+		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_FLOAT, 1, 0), 4),
+								/* [2] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0float"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "float_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = 4,
+	.key_type_id = 1,
+	.value_type_id = 2,
+	.max_entries = 1,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+{
+	.descr = "float test #4, member does not fit",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),
+								/* [1] */
+		BTF_TYPE_FLOAT_ENC(NAME_TBD, 4),		/* [2] */
+		BTF_STRUCT_ENC(NAME_TBD, 1, 2),			/* [3] */
+		BTF_MEMBER_ENC(NAME_TBD, 2, 0),
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0float\0floats\0x"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "float_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = 4,
+	.key_type_id = 1,
+	.value_type_id = 3,
+	.max_entries = 1,
+	.btf_load_err = true,
+	.err_str = "Member exceeds struct_size",
+},
+{
+	.descr = "float test #5, member is not properly aligned",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),
+								/* [1] */
+		BTF_TYPE_FLOAT_ENC(NAME_TBD, 4),		/* [2] */
+		BTF_STRUCT_ENC(NAME_TBD, 1, 8),			/* [3] */
+		BTF_MEMBER_ENC(NAME_TBD, 2, 8),
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0float\0floats\0x"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "float_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = 4,
+	.key_type_id = 1,
+	.value_type_id = 3,
+	.max_entries = 1,
+	.btf_load_err = true,
+	.err_str = "Member is not properly aligned",
+},
+{
+	.descr = "float test #6, invalid size",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),
+								/* [1] */
+		BTF_TYPE_FLOAT_ENC(NAME_TBD, 6),		/* [2] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0float"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "float_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = 6,
+	.key_type_id = 1,
+	.value_type_id = 2,
+	.max_entries = 1,
+	.btf_load_err = true,
+	.err_str = "Invalid type_size",
+},
+
 }; /* struct btf_raw_test raw_tests[] */
 
 static const char *get_next_str(const char *start, const char *end)
@@ -6630,6 +6760,7 @@ static int btf_type_size(const struct btf_type *t)
 	case BTF_KIND_PTR:
 	case BTF_KIND_TYPEDEF:
 	case BTF_KIND_FUNC:
+	case BTF_KIND_FLOAT:
 		return base_size;
 	case BTF_KIND_INT:
 		return base_size + sizeof(__u32);

tools/testing/selftests/bpf/test_btf.h

@@ -66,4 +66,7 @@
 #define BTF_FUNC_ENC(name, func_proto) \
 	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), func_proto)
 
+#define BTF_TYPE_FLOAT_ENC(name, sz) \
+	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
+
 #endif /* _TEST_BTF_H */