From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH bpf-next 2/3] libbpf: Fix relocating big-endian bitfields
Date: Fri, 22 Oct 2021 01:46:52 +0200 [thread overview]
Message-ID: <20211021234653.643302-3-iii@linux.ibm.com> (raw)
In-Reply-To: <20211021234653.643302-1-iii@linux.ibm.com>
This is the same as commit c9e982b87946 ("libbpf: Fix dumping
big-endian bitfields"), but for CO-RE. Make the code structure as
similar as possible to that of btf_dump_get_bitfield_value().
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
tools/lib/bpf/relo_core.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
index b5b8956a1be8..fd814b985e1e 100644
--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -661,13 +661,18 @@ static int bpf_core_calc_field_relo(const char *prog_name,
if (validate)
*validate = true; /* signedness is never ambiguous */
break;
- case BPF_FIELD_LSHIFT_U64:
+ case BPF_FIELD_LSHIFT_U64: {
+ __u32 bits_offset = bit_off - byte_off * 8;
+ __u8 nr_copy_bits;
+
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
- *val = 64 - (bit_off + bit_sz - byte_off * 8);
+ nr_copy_bits = bit_sz + bits_offset;
#else
- *val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8);
+ nr_copy_bits = byte_sz * 8 - bits_offset;
#endif
+ *val = 64 - nr_copy_bits;
break;
+ }
case BPF_FIELD_RSHIFT_U64:
*val = 64 - bit_sz;
if (validate)
--
2.31.1
next prev parent reply other threads:[~2021-10-21 23:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-21 23:46 [PATCH bpf-next 0/3] core_reloc fixes for s390 Ilya Leoshkevich
2021-10-21 23:46 ` [PATCH bpf-next 1/3] bpf: Use __BYTE_ORDER__ everywhere Ilya Leoshkevich
2021-10-21 23:46 ` Ilya Leoshkevich [this message]
2021-10-22 10:24 ` [PATCH bpf-next 2/3] libbpf: Fix relocating big-endian bitfields Ilya Leoshkevich
2021-10-21 23:46 ` [PATCH bpf-next 3/3] selftests/bpf: Fix test_core_reloc_mods on big-endian machines Ilya Leoshkevich
2021-10-22 23:38 ` [PATCH bpf-next 0/3] core_reloc fixes for s390 Andrii Nakryiko
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