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authorNicolas Schichan <nschichan@freebox.fr>2015-07-21 14:14:14 +0200
committerDavid S. Miller <davem@davemloft.net>2015-07-21 22:19:55 -0700
commitc18fe54b3f8d7daa6a43270f82676d6a563582a4 (patch)
tree749c52e250fc26bd2533daf555c52ff04bb1554f
parent6d715e301e950e3314d590bdbabf0c26e4fed94b (diff)
downloadlinux-c18fe54b3f8d7daa6a43270f82676d6a563582a4.tar.gz
ARM: net: fix vlan access instructions in ARM JIT.
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>
-rw-r--r--arch/arm/net/bpf_jit_32.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index d9b25242f743..c011e2296cb1 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -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;