v4.19.13 snapshot.
diff --git a/fs/proc/cpuinfo.c b/fs/proc/cpuinfo.c
new file mode 100644
index 0000000..96f1087
--- /dev/null
+++ b/fs/proc/cpuinfo.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/cpufreq.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+__weak void arch_freq_prepare_all(void)
+{
+}
+
+extern const struct seq_operations cpuinfo_op;
+static int cpuinfo_open(struct inode *inode, struct file *file)
+{
+ arch_freq_prepare_all();
+ return seq_open(file, &cpuinfo_op);
+}
+
+static const struct file_operations proc_cpuinfo_operations = {
+ .open = cpuinfo_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static int __init proc_cpuinfo_init(void)
+{
+ proc_create("cpuinfo", 0, NULL, &proc_cpuinfo_operations);
+ return 0;
+}
+fs_initcall(proc_cpuinfo_init);