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| author | Ilya Leoshkevich <iii@linux.ibm.com> | 2021-10-13 18:09:00 +0200 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2021-10-20 11:40:01 -0700 |
| commit | c9e982b879465ca74e3593ce82808aa259265a71 (patch) | |
| tree | 2d6ad1683185134022b06fd4af2aa7fa75dbb198 /tools/lib/bpf | |
| parent | b16d12f3900283e00aded9131ba1e9b2880513c3 (diff) | |
| download | linux-c9e982b879465ca74e3593ce82808aa259265a71.tar.bz2 | |
libbpf: Fix dumping big-endian bitfields
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>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211013160902.428340-3-iii@linux.ibm.com
Diffstat (limited to 'tools/lib/bpf')
| -rw-r--r-- | tools/lib/bpf/btf_dump.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 5ef42f0abed1..679bf34e3f47 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -1562,29 +1562,28 @@ static int btf_dump_get_bitfield_value(struct btf_dump *d, __u64 *value) { __u16 left_shift_bits, right_shift_bits; - __u8 nr_copy_bits, nr_copy_bytes; const __u8 *bytes = data; - int sz = t->size; + __u8 nr_copy_bits; __u64 num = 0; int i; /* Maximum supported bitfield size is 64 bits */ - if (sz > 8) { - pr_warn("unexpected bitfield size %d\n", sz); + if (t->size > 8) { + pr_warn("unexpected bitfield size %d\n", t->size); return -EINVAL; } /* 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--) + for (i = t->size - 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++) + for (i = 0; i < t->size; i++) num = num * 256 + bytes[i]; + nr_copy_bits = t->size * 8 - bits_offset; #else # error "Unrecognized __BYTE_ORDER__" #endif |