uptime.c
// SPDX-License-Identifier: GPL-2.0
#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>
static int uptime_proc_show(struct seq_file *m, void *v)
{
struct timespec uptime;
struct timespec64 idle;
u64 nsec;
u32 rem;
int i;
nsec = 0;
for_each_possible_cpu(i)
nsec += (__force u64) kcpustat_cpu(i).cpustat[CPUTIME_IDLE];
get_monotonic_boottime(&uptime);
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 __init proc_uptime_init(void)
{
proc_create_single("uptime", 0, NULL, uptime_proc_show);
return 0;
}
fs_initcall(proc_uptime_init);