bpftool: Add btf enum64 support

Add BTF_KIND_ENUM64 support.
For example, the following enum is defined in uapi bpf.h.
  $ cat core.c
  enum A {
        BPF_F_INDEX_MASK                = 0xffffffffULL,
        BPF_F_CURRENT_CPU               = BPF_F_INDEX_MASK,
        BPF_F_CTXLEN_MASK               = (0xfffffULL << 32),
  } g;
Compiled with
  clang -target bpf -O2 -g -c core.c
Using bpftool to dump types and generate format C file:
  $ bpftool btf dump file core.o
  ...
  [1] ENUM64 'A' encoding=UNSIGNED size=8 vlen=3
        'BPF_F_INDEX_MASK' val=4294967295ULL
        'BPF_F_CURRENT_CPU' val=4294967295ULL
        'BPF_F_CTXLEN_MASK' val=4503595332403200ULL
  $ bpftool btf dump file core.o format c
  ...
  enum A {
        BPF_F_INDEX_MASK = 4294967295ULL,
        BPF_F_CURRENT_CPU = 4294967295ULL,
        BPF_F_CTXLEN_MASK = 4503595332403200ULL,
  };
  ...

Note that for raw btf output, the encoding (UNSIGNED or SIGNED)
is printed out as well. The 64bit value is also represented properly
in BTF and C dump.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220607062652.3722649-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index f5dddf8ef404..125798b0bc5d 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -182,6 +182,32 @@ static int btf_dumper_enum(const struct btf_dumper *d,
 	return 0;
 }
 
+static int btf_dumper_enum64(const struct btf_dumper *d,
+			     const struct btf_type *t,
+			     const void *data)
+{
+	const struct btf_enum64 *enums = btf_enum64(t);
+	__u32 val_lo32, val_hi32;
+	__u64 value;
+	__u16 i;
+
+	value = *(__u64 *)data;
+	val_lo32 = (__u32)value;
+	val_hi32 = value >> 32;
+
+	for (i = 0; i < btf_vlen(t); i++) {
+		if (val_lo32 == enums[i].val_lo32 && val_hi32 == enums[i].val_hi32) {
+			jsonw_string(d->jw,
+				     btf__name_by_offset(d->btf,
+							 enums[i].name_off));
+			return 0;
+		}
+	}
+
+	jsonw_int(d->jw, value);
+	return 0;
+}
+
 static bool is_str_array(const struct btf *btf, const struct btf_array *arr,
 			 const char *s)
 {
@@ -542,6 +568,8 @@ static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
 		return btf_dumper_array(d, type_id, data);
 	case BTF_KIND_ENUM:
 		return btf_dumper_enum(d, t, data);
+	case BTF_KIND_ENUM64:
+		return btf_dumper_enum64(d, t, data);
 	case BTF_KIND_PTR:
 		btf_dumper_ptr(d, t, data);
 		return 0;
@@ -618,6 +646,7 @@ static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
 			      btf__name_by_offset(btf, t->name_off));
 		break;
 	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
 		BTF_PRINT_ARG("enum %s ",
 			      btf__name_by_offset(btf, t->name_off));
 		break;