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Commit c18fe54b authored by Nicolas Schichan's avatar Nicolas Schichan Committed by David S. Miller
Browse files

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: default avatarNicolas Schichan <nschichan@freebox.fr>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6d715e30

arch/arm/net/bpf_jit_32.c

+5 −3
Original line number Diff line number Diff line
@@ -889,9 +889,11 @@ static int build_body(struct jit_ctx *ctx) 
			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;