PT_REGS_PARM2_SYSCALL
#ifndef PT_REGS_PARM2_SYSCALL
#define ___bpf_syscall_args2(x, args...) ___bpf_syscall_args1(args), (unsigned long long)PT_REGS_PARM2_SYSCALL(regs)
bpf_probe_read_kernel(&arg2, sizeof(arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
int len = PT_REGS_PARM2_SYSCALL(regs);