v4.19.13 snapshot.
diff --git a/arch/x86/kernel/pmem.c b/arch/x86/kernel/pmem.c
new file mode 100644
index 0000000..6b07faa
--- /dev/null
+++ b/arch/x86/kernel/pmem.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2015, Christoph Hellwig.
+ * Copyright (c) 2015, Intel Corporation.
+ */
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+
+static int found(struct resource *res, void *data)
+{
+ return 1;
+}
+
+static __init int register_e820_pmem(void)
+{
+ struct platform_device *pdev;
+ int rc;
+
+ rc = walk_iomem_res_desc(IORES_DESC_PERSISTENT_MEMORY_LEGACY,
+ IORESOURCE_MEM, 0, -1, NULL, found);
+ if (rc <= 0)
+ return 0;
+
+ /*
+ * See drivers/nvdimm/e820.c for the implementation, this is
+ * simply here to trigger the module to load on demand.
+ */
+ pdev = platform_device_alloc("e820_pmem", -1);
+ return platform_device_add(pdev);
+}
+device_initcall(register_e820_pmem);