v4.19.13 snapshot.
diff --git a/arch/powerpc/kernel/proc_powerpc.c b/arch/powerpc/kernel/proc_powerpc.c
new file mode 100644
index 0000000..9bfbd80
--- /dev/null
+++ b/arch/powerpc/kernel/proc_powerpc.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/kernel.h>
+
+#include <asm/machdep.h>
+#include <asm/vdso_datapage.h>
+#include <asm/rtas.h>
+#include <linux/uaccess.h>
+#include <asm/prom.h>
+
+#ifdef CONFIG_PPC64
+
+static loff_t page_map_seek(struct file *file, loff_t off, int whence)
+{
+ return fixed_size_llseek(file, off, whence, PAGE_SIZE);
+}
+
+static ssize_t page_map_read( struct file *file, char __user *buf, size_t nbytes,
+ loff_t *ppos)
+{
+ return simple_read_from_buffer(buf, nbytes, ppos,
+ PDE_DATA(file_inode(file)), PAGE_SIZE);
+}
+
+static int page_map_mmap( struct file *file, struct vm_area_struct *vma )
+{
+ if ((vma->vm_end - vma->vm_start) > PAGE_SIZE)
+ return -EINVAL;
+
+ remap_pfn_range(vma, vma->vm_start,
+ __pa(PDE_DATA(file_inode(file))) >> PAGE_SHIFT,
+ PAGE_SIZE, vma->vm_page_prot);
+ return 0;
+}
+
+static const struct file_operations page_map_fops = {
+ .llseek = page_map_seek,
+ .read = page_map_read,
+ .mmap = page_map_mmap
+};
+
+
+static int __init proc_ppc64_init(void)
+{
+ struct proc_dir_entry *pde;
+
+ pde = proc_create_data("powerpc/systemcfg", S_IFREG | 0444, NULL,
+ &page_map_fops, vdso_data);
+ if (!pde)
+ return 1;
+ proc_set_size(pde, PAGE_SIZE);
+
+ return 0;
+}
+__initcall(proc_ppc64_init);
+
+#endif /* CONFIG_PPC64 */
+
+/*
+ * Create the ppc64 and ppc64/rtas directories early. This allows us to
+ * assume that they have been previously created in drivers.
+ */
+static int __init proc_ppc64_create(void)
+{
+ struct proc_dir_entry *root;
+
+ root = proc_mkdir("powerpc", NULL);
+ if (!root)
+ return 1;
+
+#ifdef CONFIG_PPC64
+ if (!proc_symlink("ppc64", NULL, "powerpc"))
+ pr_err("Failed to create link /proc/ppc64 -> /proc/powerpc\n");
+#endif
+
+ if (!of_find_node_by_path("/rtas"))
+ return 0;
+
+ if (!proc_mkdir("rtas", root))
+ return 1;
+
+ if (!proc_symlink("rtas", NULL, "powerpc/rtas"))
+ return 1;
+
+ return 0;
+}
+core_initcall(proc_ppc64_create);