1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/fs.h>
3 #include <linux/init.h>
4 #include <linux/proc_fs.h>
5 #include <linux/sched.h>
6 #include <linux/seq_file.h>
7 #include <linux/time.h>
8 #include <linux/time_namespace.h>
9 #include <linux/kernel_stat.h>
10 
uptime_proc_show(struct seq_file * m,void * v)11 static int uptime_proc_show(struct seq_file *m, void *v)
12 {
13 	struct timespec64 uptime;
14 	struct timespec64 idle;
15 	u64 idle_nsec;
16 	u32 rem;
17 	int i;
18 
19 	idle_nsec = 0;
20 	for_each_possible_cpu(i) {
21 		struct kernel_cpustat kcs;
22 
23 		kcpustat_cpu_fetch(&kcs, i);
24 		idle_nsec += get_idle_time(&kcs, i);
25 	}
26 
27 	ktime_get_boottime_ts64(&uptime);
28 	timens_add_boottime(&uptime);
29 
30 	idle.tv_sec = div_u64_rem(idle_nsec, NSEC_PER_SEC, &rem);
31 	idle.tv_nsec = rem;
32 	seq_printf(m, "%lu.%02lu %lu.%02lu\n",
33 			(unsigned long) uptime.tv_sec,
34 			(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
35 			(unsigned long) idle.tv_sec,
36 			(idle.tv_nsec / (NSEC_PER_SEC / 100)));
37 	return 0;
38 }
39 
proc_uptime_init(void)40 static int __init proc_uptime_init(void)
41 {
42 	proc_create_single("uptime", 0, NULL, uptime_proc_show);
43 	return 0;
44 }
45 fs_initcall(proc_uptime_init);
46