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| author | Artem Savkov <asavkov@redhat.com> | 2024-03-21 09:18:09 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-03-21 11:59:05 +0100 |
| commit | a51cd6bf8e10793103c5870ff9e4db295a843604 (patch) | |
| tree | b43ed013baaf135044a4b751e52cfca9749c872a /arch/arm64 | |
| parent | bpf, arm64: fix bug in BPF_LDX_MEMSX (diff) | |
| download | linux-a51cd6bf8e10793103c5870ff9e4db295a843604.tar.xz linux-a51cd6bf8e10793103c5870ff9e4db295a843604.zip | |
arm64: bpf: fix 32bit unconditional bswap
In case when is64 == 1 in emit(A64_REV32(is64, dst, dst), ctx) the
generated insn reverses byte order for both high and low 32-bit words,
resuling in an incorrect swap as indicated by the jit test:
[ 9757.262607] test_bpf: #312 BSWAP 16: 0x0123456789abcdef -> 0xefcd jited:1 8 PASS
[ 9757.264435] test_bpf: #313 BSWAP 32: 0x0123456789abcdef -> 0xefcdab89 jited:1 ret 1460850314 != -271733879 (0x5712ce8a != 0xefcdab89)FAIL (1 times)
[ 9757.266260] test_bpf: #314 BSWAP 64: 0x0123456789abcdef -> 0x67452301 jited:1 8 PASS
[ 9757.268000] test_bpf: #315 BSWAP 64: 0x0123456789abcdef >> 32 -> 0xefcdab89 jited:1 8 PASS
[ 9757.269686] test_bpf: #316 BSWAP 16: 0xfedcba9876543210 -> 0x1032 jited:1 8 PASS
[ 9757.271380] test_bpf: #317 BSWAP 32: 0xfedcba9876543210 -> 0x10325476 jited:1 ret -1460850316 != 271733878 (0xa8ed3174 != 0x10325476)FAIL (1 times)
[ 9757.273022] test_bpf: #318 BSWAP 64: 0xfedcba9876543210 -> 0x98badcfe jited:1 7 PASS
[ 9757.274721] test_bpf: #319 BSWAP 64: 0xfedcba9876543210 >> 32 -> 0x10325476 jited:1 9 PASS
Fix this by forcing 32bit variant of rev32.
Fixes: 1104247f3f979 ("bpf, arm64: Support unconditional bswap")
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Tested-by: Puranjay Mohan <puranjay12@gmail.com>
Acked-by: Puranjay Mohan <puranjay12@gmail.com>
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Message-ID: <20240321081809.158803-1-asavkov@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/net/bpf_jit_comp.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 48b19a233299..122021f9bdfc 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -943,7 +943,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, emit(A64_UXTH(is64, dst, dst), ctx); break; case 32: - emit(A64_REV32(is64, dst, dst), ctx); + emit(A64_REV32(0, dst, dst), ctx); /* upper 32 bits already cleared */ break; case 64: |