xref: /linux/fs/proc/uptime.c (revision bb29b957eaaa15be33243550d9ee576c2d601669)
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 
12 static 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 
19 	idle_nsec = kcpustat_field_total(CPUTIME_IDLE, cpu_possible_mask);
20 	ktime_get_boottime_ts64(&uptime);
21 	timens_add_boottime(&uptime);
22 
23 	idle.tv_sec = div_u64_rem(idle_nsec, NSEC_PER_SEC, &rem);
24 	idle.tv_nsec = rem;
25 	seq_printf(m, "%lu.%02lu %lu.%02lu\n",
26 			(unsigned long) uptime.tv_sec,
27 			(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
28 			(unsigned long) idle.tv_sec,
29 			(idle.tv_nsec / (NSEC_PER_SEC / 100)));
30 	return 0;
31 }
32 
33 static int __init proc_uptime_init(void)
34 {
35 	struct proc_dir_entry *pde;
36 
37 	pde = proc_create_single("uptime", 0, NULL, uptime_proc_show);
38 	pde_make_permanent(pde);
39 	return 0;
40 }
41 fs_initcall(proc_uptime_init);
42