bpf: disasm: add support for BPF_JMP|BPF_JA|BPF_X

Add support for indirect jump instruction.

Example output from bpftool:

   0: (79) r3 = *(u64 *)(r1 +0)
   1: (25) if r3 > 0x4 goto pc+666
   2: (67) r3 <<= 3
   3: (18) r1 = 0xffffbeefspameggs
   5: (0f) r1 += r3
   6: (79) r1 = *(u64 *)(r1 +0)
   7: (0d) gotox r1

Signed-off-by: Anton Protopopov <[email protected]>
Acked-by: Eduard Zingerman <[email protected]>

Author: aspsk

kernel/bpf/disasm.c

@@ -358,6 +358,9 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
 		} else if (insn->code == (BPF_JMP | BPF_JA)) {
 			verbose(cbs->private_data, "(%02x) goto pc%+d\n",
 				insn->code, insn->off);
+		} else if (insn->code == (BPF_JMP | BPF_JA | BPF_X)) {
+			verbose(cbs->private_data, "(%02x) gotox r%d\n",
+				insn->code, insn->dst_reg);
 		} else if (insn->code == (BPF_JMP | BPF_JCOND) &&
 			   insn->src_reg == BPF_MAY_GOTO) {
 			verbose(cbs->private_data, "(%02x) may_goto pc%+d\n",