BPF_R0
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,
return BPF_R0;
BPF_R0 = (u32) atomic_cmpxchg(
(u32) BPF_R0, (u32) SRC);
BPF_R0 = (u64) atomic64_cmpxchg(
(u64) BPF_R0, (u64) SRC);