1 files changed, 52 insertions, 0 deletions
diff --git a/fs/proc/uptime.c b/fs/proc/uptime.c
new file mode 100644
index 000000000..33de567c2
--- /dev/null
+++ b/fs/proc/uptime.c
@@ -0,0 +1,52 @@
+#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>
+#include <linux/cputime.h>
+
+static int uptime_proc_show(struct seq_file *m, void *v)
+{
+	struct timespec uptime;
+	struct timespec idle;
+	u64 idletime;
+	u64 nsec;
+	u32 rem;
+	int i;
+
+	idletime = 0;
+	for_each_possible_cpu(i)
+		idletime += (__force u64) kcpustat_cpu(i).cpustat[CPUTIME_IDLE];
+
+	get_monotonic_boottime(&uptime);
+	nsec = cputime64_to_jiffies64(idletime) * TICK_NSEC;
+	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 uptime_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, uptime_proc_show, NULL);
+}
+
+static const struct file_operations uptime_proc_fops = {
+	.open		= uptime_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init proc_uptime_init(void)
+{
+	proc_create("uptime", 0, NULL, &uptime_proc_fops);
+	return 0;
+}
+fs_initcall(proc_uptime_init);