tools/bpftool: Add BTF_KIND_FLOAT support

mainline inclusion
from mainline-5.13-rc1
commit 737e0f91
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5Q927
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=737e0f919a8d2a313618d8ac67d50e8223bc5d74

-------------------------------------------------

Only dumping support needs to be adjusted, the code structure follows
that of BTF_KIND_INT. Example plain and JSON outputs:

    [4] FLOAT 'float' size=4
    {"id":4,"kind":"FLOAT","name":"float","size":4}
Signed-off-by: NIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210226202256.116518-5-iii@linux.ibm.com
(cherry picked from commit 737e0f91)
Signed-off-by: NWang Yufen <wangyufen@huawei.com>

Conflicts:
	tools/bpf/bpftool/btf.c

tools/bpf/bpftool/btf.c

@@ -36,6 +36,7 @@ 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",
 	[BTF_KIND_DECL_TAG]	= "DECL_TAG",
 	[BTF_KIND_TYPE_TAG]	= "TYPE_TAG",
 };
@@ -330,6 +331,13 @@ static int dump_btf_type(const struct btf *btf, __u32 id,
 			jsonw_end_array(w);
 		break;
 	}
+	case BTF_KIND_FLOAT: {
+		if (json_output)
+			jsonw_uint_field(w, "size", t->size);
+		else
+			printf(" size=%u", t->size);
+		break;
+	}
 	case BTF_KIND_DECL_TAG: {
 		const struct btf_decl_tag *tag = (const void *)(t + 1);
 

tools/bpf/bpftool/btf_dumper.c

@@ -598,6 +598,7 @@ static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
 	switch (BTF_INFO_KIND(t->info)) {
 	case BTF_KIND_INT:
 	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_FLOAT:
 		BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
 		break;
 	case BTF_KIND_STRUCT: