1 files changed, 111 insertions, 0 deletions
diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
new file mode 100644
index 000000000..d7d642350
--- /dev/null
+++ b/drivers/xen/xenfs/super.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  xenfs.c - a filesystem for passing info between the a domain and
+ *  the hypervisor.
+ *
+ * 2008-10-07  Alex Zeffertt    Replaced /proc/xen/xenbus with xenfs filesystem
+ *                              and /proc/xen compatibility mount point.
+ *                              Turned xenfs into a loadable module.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/magic.h>
+
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+
+#include "xenfs.h"
+#include "../privcmd.h"
+
+#include <asm/xen/hypervisor.h>
+
+MODULE_DESCRIPTION("Xen filesystem");
+MODULE_LICENSE("GPL");
+
+static ssize_t capabilities_read(struct file *file, char __user *buf,
+				 size_t size, loff_t *off)
+{
+	char *tmp = "";
+
+	if (xen_initial_domain())
+		tmp = "control_d\n";
+
+	return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp));
+}
+
+static const struct file_operations capabilities_file_ops = {
+	.read = capabilities_read,
+	.llseek = default_llseek,
+};
+
+static int xenfs_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	static const struct tree_descr xenfs_files[] = {
+		[2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
+		{ "capabilities", &capabilities_file_ops, S_IRUGO },
+		{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
+		{""},
+	};
+
+	static const struct tree_descr xenfs_init_files[] = {
+		[2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
+		{ "capabilities", &capabilities_file_ops, S_IRUGO },
+		{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
+		{ "xsd_kva", &xsd_kva_file_ops, S_IRUSR|S_IWUSR},
+		{ "xsd_port", &xsd_port_file_ops, S_IRUSR|S_IWUSR},
+#ifdef CONFIG_XEN_SYMS
+		{ "xensyms", &xensyms_ops, S_IRUSR},
+#endif
+		{""},
+	};
+
+	return simple_fill_super(sb, XENFS_SUPER_MAGIC,
+			xen_initial_domain() ? xenfs_init_files : xenfs_files);
+}
+
+static int xenfs_get_tree(struct fs_context *fc)
+{
+	return get_tree_single(fc, xenfs_fill_super);
+}
+
+static const struct fs_context_operations xenfs_context_ops = {
+	.get_tree	= xenfs_get_tree,
+};
+
+static int xenfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &xenfs_context_ops;
+	return 0;
+}
+
+static struct file_system_type xenfs_type = {
+	.owner =	THIS_MODULE,
+	.name =		"xenfs",
+	.init_fs_context = xenfs_init_fs_context,
+	.kill_sb =	kill_litter_super,
+};
+MODULE_ALIAS_FS("xenfs");
+
+static int __init xenfs_init(void)
+{
+	if (xen_domain())
+		return register_filesystem(&xenfs_type);
+
+	return 0;
+}
+
+static void __exit xenfs_exit(void)
+{
+	if (xen_domain())
+		unregister_filesystem(&xenfs_type);
+}
+
+module_init(xenfs_init);
+module_exit(xenfs_exit);
+