netdev - [PATCH net-next 2/6] net/bpf_jit: ARM: split VLAN_PRESENT bit handling from VLAN

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Message-Id: <83e17cf9afe848670ef908da458754e589592bf5.1483492355.git.mirq-linux@rere.qmqm.pl>
Date:   Wed,  4 Jan 2017 02:18:26 +0100 (CET)
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     netdev@...r.kernel.org
Cc:     Russell King <linux@...linux.org.uk>,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH net-next 2/6] net/bpf_jit: ARM: split VLAN_PRESENT bit
 handling from VLAN_TCI

Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
v2: remove one insn for big-endians

 arch/arm/net/bpf_jit_32.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 93d0b6d0b63e..0700cbbe4f14 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -915,17 +915,21 @@ static int build_body(struct jit_ctx *ctx)
 			emit(ARM_LDR_I(r_A, r_skb, off), ctx);
 			break;
 		case BPF_ANC | SKF_AD_VLAN_TAG:
-		case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
 			ctx->seen |= SEEN_SKB;
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
 			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_TAG_PRESENT, ctx);
-			else {
-				OP_IMM3(ARM_LSR, r_A, r_A, 12, ctx);
+#ifdef VLAN_TAG_PRESENT
+			OP_IMM3(ARM_AND, r_A, r_A, ~VLAN_TAG_PRESENT, ctx);
+#endif
+			break;
+		case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
+			off = PKT_VLAN_PRESENT_OFFSET();
+			emit(ARM_LDRB_I(r_A, r_skb, off), ctx);
+			if (PKT_VLAN_PRESENT_BIT)
+				OP_IMM3(ARM_LSR, r_A, r_A, PKT_VLAN_PRESENT_BIT, ctx);
+			if (PKT_VLAN_PRESENT_BIT < 7)
 				OP_IMM3(ARM_AND, r_A, r_A, 0x1, ctx);
-			}
 			break;
 		case BPF_ANC | SKF_AD_PKTTYPE:
 			ctx->seen |= SEEN_SKB;
-- 
2.11.0