// 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/time_namespace.h>
#include <linux/kernel_stat.h>
#include "internal.h"

static int uptime_proc_show(struct seq_file *m, void *v)
{
        struct timespec64 uptime;
        struct timespec64 idle;
        u64 idle_nsec;
        u32 rem;
        int i;

        idle_nsec = 0;
        for_each_possible_cpu(i) {
                struct kernel_cpustat kcs;

                kcpustat_cpu_fetch(&kcs, i);
                idle_nsec += get_idle_time(&kcs, i);
        }

        ktime_get_boottime_ts64(&uptime);
        timens_add_boottime(&uptime);

        idle.tv_sec = div_u64_rem(idle_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)
{
        struct proc_dir_entry *pde;

        pde = proc_create_single("uptime", 0, NULL, uptime_proc_show);
        pde_make_permanent(pde);
        return 0;
}
fs_initcall(proc_uptime_init);