ARM: net: fix vlan access instructions in ARM JIT.
authorNicolas Schichan <nschichan@freebox.fr>
Tue, 21 Jul 2015 12:14:14 +0000 (14:14 +0200)
committerDavid S. Miller <davem@davemloft.net>
Wed, 22 Jul 2015 05:19:55 +0000 (22:19 -0700)
This makes BPF_ANC | SKF_AD_VLAN_TAG and BPF_ANC | SKF_AD_VLAN_TAG_PRESENT
have the same behaviour as the in kernel VM and makes the test_bpf LD_VLAN_TAG
and LD_VLAN_TAG_PRESENT tests pass.

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
arch/arm/net/bpf_jit_32.c

index d9b25242f7433e75b8feb66175985cfed19cd723..c011e2296cb1e681863338972c6ce79f836bb6be 100644 (file)
@@ -889,9 +889,11 @@ b_epilogue:
                        off = offsetof(struct sk_buff, vlan_tci);
                        emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
                        if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
-                               OP_IMM3(ARM_AND, r_A, r_A, VLAN_VID_MASK, ctx);
-                       else
-                               OP_IMM3(ARM_AND, r_A, r_A, VLAN_TAG_PRESENT, ctx);
+                               OP_IMM3(ARM_AND, r_A, r_A, ~VLAN_TAG_PRESENT, ctx);
+                       else {
+                               OP_IMM3(ARM_LSR, r_A, r_A, 12, ctx);
+                               OP_IMM3(ARM_AND, r_A, r_A, 0x1, ctx);
+                       }
                        break;
                case BPF_ANC | SKF_AD_QUEUE:
                        ctx->seen |= SEEN_SKB;