From: Ben Dooks <ben.dooks@codethink.co.uk>
To: ast@kernel.org, daniel@iogearbox.net
Cc: bpf@vger.kernel.org, Ben Dooks <ben.dooks@codethink.co.uk>
Subject: [PATCH] bpf: remove trunctaiton warning in BPF_LD_IMM64_RAW
Date: Thu, 14 Mar 2024 10:31:53 +0000 [thread overview]
Message-ID: <20240314103153.2489252-1-ben.dooks@codethink.co.uk> (raw)
When building W=1, the following warningds get generated by lib/test_bpf.c
due to the BPF_LD_IMM64_RAW() truncating a 64bit to 32bit value without
a specific mask to do so.
lib/test_bpf.c:6441:25: warning: cast truncates bits from constant value (ffffffff0000 becomes ffff0000)
lib/test_bpf.c:6442:25: warning: cast truncates bits from constant value (ffffffff0000 becomes ffff0000)
lib/test_bpf.c:6473:25: warning: cast truncates bits from constant value (123456789abcdef becomes 89abcdef)
lib/test_bpf.c:6489:25: warning: cast truncates bits from constant value (123456789abcdef becomes 89abcdef)
lib/test_bpf.c:6490:25: warning: cast truncates bits from constant value (123456780a0c0e0 becomes 80a0c0e0)
lib/test_bpf.c:6599:25: warning: cast truncates bits from constant value (123456789abcdef becomes 89abcdef)
lib/test_bpf.c:6637:25: warning: cast truncates bits from constant value (ffffffff0000 becomes ffff0000)
(more warnings truncated)
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
---
include/linux/filter.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index c99bc3df2d28..c1ff6511f365 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -238,7 +238,7 @@ static inline bool insn_is_zext(const struct bpf_insn *insn)
.dst_reg = DST, \
.src_reg = SRC, \
.off = 0, \
- .imm = (__u32) (IMM) }), \
+ .imm = (__u32) ((IMM) & (__u64)0xffffffff) }), \
((struct bpf_insn) { \
.code = 0, /* zero is reserved opcode */ \
.dst_reg = 0, \
--
2.37.2.352.g3c44437643
next reply other threads:[~2024-03-14 10:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-14 10:31 Ben Dooks [this message]
2024-03-14 19:58 ` [PATCH] bpf: remove trunctaiton warning in BPF_LD_IMM64_RAW Stanislav Fomichev
2024-03-14 22:08 ` Alexei Starovoitov
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