netdev - [PATCH v2 net-next 2/2] bpf/verifier: improve disassembly of BPF

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Date:   Tue, 26 Sep 2017 16:35:29 +0100
From:   Edward Cree <ecree@...arflare.com>
To:     <davem@...emloft.net>
CC:     <netdev@...r.kernel.org>, <daniel@...earbox.net>,
        <alexei.starovoitov@...il.com>, <ys114321@...il.com>
Subject: [PATCH v2 net-next 2/2] bpf/verifier: improve disassembly of BPF_NEG
 instructions

BPF_NEG takes only one operand, unlike the bulk of BPF_ALU[64] which are
 compound-assignments.  So give it its own format in print_bpf_insn().

Signed-off-by: Edward Cree <ecree@...arflare.com>
---
 kernel/bpf/verifier.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 3aaa3262..04e0508 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -344,6 +344,11 @@ static void print_bpf_insn(const struct bpf_verifier_env *env,
 				verbose("BUG_alu64_%02x\n", insn->code);
 			else
 				print_bpf_end_insn(env, insn);
+		} else if (BPF_OP(insn->code) == BPF_NEG) {
+			verbose("(%02x) r%d = %s-r%d\n",
+				insn->code, insn->dst_reg,
+				class == BPF_ALU ? "(u32) " : "",
+				insn->dst_reg);
 		} else if (BPF_SRC(insn->code) == BPF_X) {
 			verbose("(%02x) %sr%d %s %sr%d\n",
 				insn->code, class == BPF_ALU ? "(u32) " : "",