netdev - [PATCH net-next 06/13] nfp: bpf: don't do ld/shifts combination if shifts are jump destination

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Message-Id: <20171201053300.17503-7-jakub.kicinski@netronome.com>
Date:   Thu, 30 Nov 2017 21:32:53 -0800
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     netdev@...r.kernel.org
Cc:     oss-drivers@...ronome.com, Jiong Wang <jiong.wang@...ronome.com>
Subject: [PATCH net-next 06/13] nfp: bpf: don't do ld/shifts combination if shifts are jump destination

From: Jiong Wang <jiong.wang@...ronome.com>

If any of the shift insns in the ld/shift sequence is jump destination,
don't do combination.

Signed-off-by: Jiong Wang <jiong.wang@...ronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
---
 drivers/net/ethernet/netronome/nfp/bpf/jit.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
index f2317b764222..54915a3b8a7e 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
@@ -2181,6 +2181,10 @@ static void nfp_bpf_opt_ld_shift(struct nfp_prog *nfp_prog)
 		if (next1.imm != 0x20 || next2.imm != 0x20)
 			continue;
 
+		if (meta2->flags & FLAG_INSN_IS_JUMP_DST ||
+		    meta3->flags & FLAG_INSN_IS_JUMP_DST)
+			continue;
+
 		meta2->skip = true;
 		meta3->skip = true;
 	}
-- 
2.15.0