1 files changed, 45 insertions, 0 deletions
diff --git a/fs/proc/uptime.c b/fs/proc/uptime.c
new file mode 100644
index 000000000..deb99bc9b
--- /dev/null
+++ b/fs/proc/uptime.c
@@ -0,0 +1,45 @@
+// 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>
+
+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)
+{
+	proc_create_single("uptime", 0, NULL, uptime_proc_show);
+	return 0;
+}
+fs_initcall(proc_uptime_init);