releases/6.6.26/arm64-bpf-fix-32bit-unconditional-bswap.patch

   1 From cf3ba17a91a62832ebb995d45bc66ac6ea0ef9c3 Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Thu, 21 Mar 2024 09:18:09 +0100
   4 Subject: arm64: bpf: fix 32bit unconditional bswap
   5
   6 From: Artem Savkov <asavkov@redhat.com>
   7
   8 [ Upstream commit a51cd6bf8e10793103c5870ff9e4db295a843604 ]
   9
  10 In case when is64 == 1 in emit(A64_REV32(is64, dst, dst), ctx) the
  11 generated insn reverses byte order for both high and low 32-bit words,
  12 resuling in an incorrect swap as indicated by the jit test:
  13
  14 [ 9757.262607] test_bpf: #312 BSWAP 16: 0x0123456789abcdef -> 0xefcd jited:1 8 PASS
  15 [ 9757.264435] test_bpf: #313 BSWAP 32: 0x0123456789abcdef -> 0xefcdab89 jited:1 ret 1460850314 != -271733879 (0x5712ce8a != 0xefcdab89)FAIL (1 times)
  16 [ 9757.266260] test_bpf: #314 BSWAP 64: 0x0123456789abcdef -> 0x67452301 jited:1 8 PASS
  17 [ 9757.268000] test_bpf: #315 BSWAP 64: 0x0123456789abcdef >> 32 -> 0xefcdab89 jited:1 8 PASS
  18 [ 9757.269686] test_bpf: #316 BSWAP 16: 0xfedcba9876543210 -> 0x1032 jited:1 8 PASS
  19 [ 9757.271380] test_bpf: #317 BSWAP 32: 0xfedcba9876543210 -> 0x10325476 jited:1 ret -1460850316 != 271733878 (0xa8ed3174 != 0x10325476)FAIL (1 times)
  20 [ 9757.273022] test_bpf: #318 BSWAP 64: 0xfedcba9876543210 -> 0x98badcfe jited:1 7 PASS
  21 [ 9757.274721] test_bpf: #319 BSWAP 64: 0xfedcba9876543210 >> 32 -> 0x10325476 jited:1 9 PASS
  22
  23 Fix this by forcing 32bit variant of rev32.
  24
  25 Fixes: 1104247f3f979 ("bpf, arm64: Support unconditional bswap")
  26 Signed-off-by: Artem Savkov <asavkov@redhat.com>
  27 Tested-by: Puranjay Mohan <puranjay12@gmail.com>
  28 Acked-by: Puranjay Mohan <puranjay12@gmail.com>
  29 Acked-by: Xu Kuohai <xukuohai@huawei.com>
  30 Message-ID: <20240321081809.158803-1-asavkov@redhat.com>
  31 Signed-off-by: Alexei Starovoitov <ast@kernel.org>
  32 Signed-off-by: Sasha Levin <sashal@kernel.org>
  33 ---
  34  arch/arm64/net/bpf_jit_comp.c | 2 +-
  35  1 file changed, 1 insertion(+), 1 deletion(-)
  36
  37 diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
  38 index 5fe4d8b3fdc89..29196dce9b91d 100644
  39 --- a/arch/arm64/net/bpf_jit_comp.c
  40 +++ b/arch/arm64/net/bpf_jit_comp.c
  41 @@ -876,7 +876,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
  42                         emit(A64_UXTH(is64, dst, dst), ctx);
  43                         break;
  44                 case 32:
  45 -                       emit(A64_REV32(is64, dst, dst), ctx);
  46 +                       emit(A64_REV32(0, dst, dst), ctx);
  47                         /* upper 32 bits already cleared */
  48                         break;
  49                 case 64:
  50 --
  51 2.43.0
  52