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/kernel_stat.h>
   9
  10static int uptime_proc_show(struct seq_file *m, void *v)
  11{
  12        struct timespec64 uptime;
  13        struct timespec64 idle;
  14        u64 nsec;
  15        u32 rem;
  16        int i;
  17
  18        nsec = 0;
  19        for_each_possible_cpu(i)
  20                nsec += (__force u64) kcpustat_cpu(i).cpustat[CPUTIME_IDLE];
  21
  22        ktime_get_boottime_ts64(&uptime);
  23        idle.tv_sec = div_u64_rem(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
  33static int __init proc_uptime_init(void)
  34{
  35        proc_create_single("uptime", 0, NULL, uptime_proc_show);
  36        return 0;
  37}
  38fs_initcall(proc_uptime_init);
  39