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#include "internal.h"
11
12static int uptime_proc_show(struct seq_file *m, void *v)
13{
14	struct timespec64 uptime;
15	struct timespec64 idle;
16	u64 idle_nsec;
17	u32 rem;
18	int i;
19
20	idle_nsec = 0;
21	for_each_possible_cpu(i) {
22		struct kernel_cpustat kcs;
23
24		kcpustat_cpu_fetch(&kcs, i);
25		idle_nsec += get_idle_time(&kcs, i);
26	}
27
28	ktime_get_boottime_ts64(&uptime);
29	timens_add_boottime(&uptime);
30
31	idle.tv_sec = div_u64_rem(idle_nsec, NSEC_PER_SEC, &rem);
32	idle.tv_nsec = rem;
33	seq_printf(m, "%lu.%02lu %lu.%02lu\n",
34			(unsigned long) uptime.tv_sec,
35			(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
36			(unsigned long) idle.tv_sec,
37			(idle.tv_nsec / (NSEC_PER_SEC / 100)));
38	return 0;
39}
40
41static int __init proc_uptime_init(void)
42{
43	struct proc_dir_entry *pde;
44
45	pde = proc_create_single("uptime", 0, NULL, uptime_proc_show);
46	pde_make_permanent(pde);
47	return 0;
48}
49fs_initcall(proc_uptime_init);
50