LXR linux/fs/proc/uptime.c

   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
  11static int uptime_proc_show(struct seq_file *m, void *v)
  12{
  13        struct timespec64 uptime;
  14        struct timespec64 idle;
  15        u64 nsec;
  16        u32 rem;
  17        int i;
  18
  19        nsec = 0;
  20        for_each_possible_cpu(i)
  21                nsec += (__force u64) kcpustat_cpu(i).cpustat[CPUTIME_IDLE];
  22
  23        ktime_get_boottime_ts64(&uptime);
  24        timens_add_boottime(&uptime);
  25
  26        idle.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
  27        idle.tv_nsec = rem;
  28        seq_printf(m, "%lu.%02lu %lu.%02lu\n",
  29                        (unsigned long) uptime.tv_sec,
  30                        (uptime.tv_nsec / (NSEC_PER_SEC / 100)),
  31                        (unsigned long) idle.tv_sec,
  32                        (idle.tv_nsec / (NSEC_PER_SEC / 100)));
  33        return 0;
  34}
  35
  36static int __init proc_uptime_init(void)
  37{
  38        proc_create_single("uptime", 0, NULL, uptime_proc_show);
  39        return 0;
  40}
  41fs_initcall(proc_uptime_init);
  42