xref: /openbmc/linux/fs/proc/uptime.c (revision ef1d6178)
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 
uptime_proc_show(struct seq_file * m,void * v)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 	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 
proc_uptime_init(void)41 static 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 }
49 fs_initcall(proc_uptime_init);
50