BPF_R2
BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
BPF_R2 = r2; \