[PATCH bpf-next 2/3] libbpf: Fix dumping big-endian bitfields

[Ilya Leoshkevich <iii@linux.ibm.com>]

On big-endian arches not only bytes, but also bits are numbered in
reverse order (see e.g. S/390 ELF ABI Supplement, but this is also true
for other big-endian arches as well).

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 tools/lib/bpf/btf_dump.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index ad6df97295ae..ab45771d0cb4 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -1577,14 +1577,15 @@ static int btf_dump_get_bitfield_value(struct btf_dump *d,
 	/* Bitfield value retrieval is done in two steps; first relevant bytes are
 	 * stored in num, then we left/right shift num to eliminate irrelevant bits.
 	 */
-	nr_copy_bits = bit_sz + bits_offset;
 	nr_copy_bytes = t->size;
 #if __BYTE_ORDER == __LITTLE_ENDIAN
 	for (i = nr_copy_bytes - 1; i >= 0; i--)
 		num = num * 256 + bytes[i];
+	nr_copy_bits = bit_sz + bits_offset;
 #elif __BYTE_ORDER == __BIG_ENDIAN
 	for (i = 0; i < nr_copy_bytes; i++)
 		num = num * 256 + bytes[i];
+	nr_copy_bits = nr_copy_bytes * 8 - bits_offset;
 #else
 # error "Unrecognized __BYTE_ORDER__"
 #endif
-- 
2.31.1