text: #include <linux/fs.h>
  #include <linux/init.h>
  #include <linux/proc_fs.h>
  #include <linux/sched.h>
  #include <linux/seq_file.h>
  #include <linux/time.h>
  #include <linux/kernel_stat.h>
  #include <asm/cputime.h>
  
  static int uptime_proc_show(struct seq_file *m, void *v)
  {
  	struct timespec uptime;
  	struct timespec idle;
  	u64 idletime;
  	u64 nsec;
  	u32 rem;
  	int i;
  
  	idletime = 0;
  	for_each_possible_cpu(i)
  		idletime += (__force u64) kcpustat_cpu(i).cpustat[CPUTIME_IDLE];
  
  	get_monotonic_boottime(&uptime);
  	nsec = cputime64_to_jiffies64(idletime) * TICK_NSEC;
  	idle.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
  	idle.tv_nsec = rem;
  	seq_printf(m, "%lu.%02lu %lu.%02lu\n",
  			(unsigned long) uptime.tv_sec,
  			(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
  			(unsigned long) idle.tv_sec,
  			(idle.tv_nsec / (NSEC_PER_SEC / 100)));
  	return 0;
  }
  
  static int uptime_proc_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, uptime_proc_show, NULL);
  }
  
  static const struct file_operations uptime_proc_fops = {
  	.open		= uptime_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  static int __init proc_uptime_init(void)
  {
  	proc_create("uptime", 0, NULL, &uptime_proc_fops);
  	return 0;
  }
  module_init(proc_uptime_init);
  