5 files changed, 181 insertions, 12 deletions

diff --git a/drivers/xen/xenfs/Makefile b/drivers/xen/xenfs/Makefile
index b019865fcc56..8490644df1a3 100644
--- a/drivers/xen/xenfs/Makefile
+++ b/drivers/xen/xenfs/Makefile
@@ -1,4 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_XENFS) += xenfs.o
 
 xenfs-y			  = super.o
 xenfs-$(CONFIG_XEN_DOM0) += xenstored.o
+xenfs-$(CONFIG_XEN_SYMS) += xensyms.o
diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
index 06092e0fe8ce..37ea7c5c0346 100644
--- a/drivers/xen/xenfs/super.c
+++ b/drivers/xen/xenfs/super.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  xenfs.c - a filesystem for passing info between the a domain and
  *  the hypervisor.
@@ -13,13 +14,14 @@
 #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 "../xenbus/xenbus_comms.h"
 
 #include <asm/xen/hypervisor.h>
 
@@ -42,21 +44,24 @@ static const struct file_operations capabilities_file_ops = {
 	.llseek = default_llseek,
 };
 
-static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
+static int xenfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
-	static struct tree_descr xenfs_files[] = {
+	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 struct tree_descr xenfs_init_files[] = {
+	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
 		{""},
 	};
 
@@ -64,18 +69,26 @@ static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
 			xen_initial_domain() ? xenfs_init_files : xenfs_files);
 }
 
-static struct dentry *xenfs_mount(struct file_system_type *fs_type,
-				  int flags, const char *dev_name,
-				  void *data)
+static int xenfs_get_tree(struct fs_context *fc)
 {
-	return mount_single(fs_type, flags, data, xenfs_fill_super);
+	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",
-	.mount =	xenfs_mount,
-	.kill_sb =	kill_litter_super,
+	.init_fs_context = xenfs_init_fs_context,
+	.kill_sb =	kill_anon_super,
 };
 MODULE_ALIAS_FS("xenfs");
 
@@ -84,7 +97,6 @@ static int __init xenfs_init(void)
 	if (xen_domain())
 		return register_filesystem(&xenfs_type);
 
-	pr_info("not registering filesystem on non-xen platform\n");
 	return 0;
 }
 
diff --git a/drivers/xen/xenfs/xenfs.h b/drivers/xen/xenfs/xenfs.h
index 6b80c7779c02..cfe4874b83a7 100644
--- a/drivers/xen/xenfs/xenfs.h
+++ b/drivers/xen/xenfs/xenfs.h
@@ -1,7 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _XENFS_XENBUS_H
 #define _XENFS_XENBUS_H
 
 extern const struct file_operations xsd_kva_file_ops;
 extern const struct file_operations xsd_port_file_ops;
+extern const struct file_operations xensyms_ops;
 
 #endif	/* _XENFS_XENBUS_H */
diff --git a/drivers/xen/xenfs/xenstored.c b/drivers/xen/xenfs/xenstored.c
index fef20dbc6a5c..f59235f9f8a2 100644
--- a/drivers/xen/xenfs/xenstored.c
+++ b/drivers/xen/xenfs/xenstored.c
@@ -1,12 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
 
 #include <xen/page.h>
+#include <xen/xenbus.h>
 
 #include "xenfs.h"
-#include "../xenbus/xenbus_comms.h"
 
 static ssize_t xsd_read(struct file *file, char __user *buf,
 			    size_t size, loff_t *off)
diff --git a/drivers/xen/xenfs/xensyms.c b/drivers/xen/xenfs/xensyms.c
new file mode 100644
index 000000000000..088b7f02c358
--- /dev/null
+++ b/drivers/xen/xenfs/xensyms.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/slab.h>
+#include <xen/interface/platform.h>
+#include <asm/xen/hypercall.h>
+#include <xen/xen-ops.h>
+#include "xenfs.h"
+
+
+#define XEN_KSYM_NAME_LEN 127 /* Hypervisor may have different name length */
+
+struct xensyms {
+	struct xen_platform_op op;
+	char *name;
+	uint32_t namelen;
+};
+
+/* Grab next output page from the hypervisor */
+static int xensyms_next_sym(struct xensyms *xs)
+{
+	int ret;
+	struct xenpf_symdata *symdata = &xs->op.u.symdata;
+	uint64_t symnum;
+
+	memset(xs->name, 0, xs->namelen);
+	symdata->namelen = xs->namelen;
+
+	symnum = symdata->symnum;
+
+	ret = HYPERVISOR_platform_op(&xs->op);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * If hypervisor's symbol didn't fit into the buffer then allocate
+	 * a larger buffer and try again.
+	 */
+	if (unlikely(symdata->namelen > xs->namelen)) {
+		kfree(xs->name);
+
+		xs->namelen = symdata->namelen;
+		xs->name = kzalloc(xs->namelen, GFP_KERNEL);
+		if (!xs->name)
+			return -ENOMEM;
+
+		set_xen_guest_handle(symdata->name, xs->name);
+		symdata->symnum = symnum; /* Rewind */
+
+		ret = HYPERVISOR_platform_op(&xs->op);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (symdata->symnum == symnum)
+		/* End of symbols */
+		return 1;
+
+	return 0;
+}
+
+static void *xensyms_start(struct seq_file *m, loff_t *pos)
+{
+	struct xensyms *xs = m->private;
+
+	xs->op.u.symdata.symnum = *pos;
+
+	if (xensyms_next_sym(xs))
+		return NULL;
+
+	return m->private;
+}
+
+static void *xensyms_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	struct xensyms *xs = m->private;
+
+	*pos = xs->op.u.symdata.symnum;
+
+	if (xensyms_next_sym(xs))
+		return NULL;
+
+	return p;
+}
+
+static int xensyms_show(struct seq_file *m, void *p)
+{
+	struct xensyms *xs = m->private;
+	struct xenpf_symdata *symdata = &xs->op.u.symdata;
+
+	seq_printf(m, "%016llx %c %s\n", symdata->address,
+		   symdata->type, xs->name);
+
+	return 0;
+}
+
+static void xensyms_stop(struct seq_file *m, void *p)
+{
+}
+
+static const struct seq_operations xensyms_seq_ops = {
+	.start = xensyms_start,
+	.next = xensyms_next,
+	.show = xensyms_show,
+	.stop = xensyms_stop,
+};
+
+static int xensyms_open(struct inode *inode, struct file *file)
+{
+	struct seq_file *m;
+	struct xensyms *xs;
+	int ret;
+
+	ret = seq_open_private(file, &xensyms_seq_ops,
+			       sizeof(struct xensyms));
+	if (ret)
+		return ret;
+
+	m = file->private_data;
+	xs = m->private;
+
+	xs->namelen = XEN_KSYM_NAME_LEN + 1;
+	xs->name = kzalloc(xs->namelen, GFP_KERNEL);
+	if (!xs->name) {
+		seq_release_private(inode, file);
+		return -ENOMEM;
+	}
+	set_xen_guest_handle(xs->op.u.symdata.name, xs->name);
+	xs->op.cmd = XENPF_get_symbol;
+	xs->op.u.symdata.namelen = xs->namelen;
+
+	return 0;
+}
+
+static int xensyms_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = file->private_data;
+	struct xensyms *xs = m->private;
+
+	kfree(xs->name);
+	return seq_release_private(inode, file);
+}
+
+const struct file_operations xensyms_ops = {
+	.open = xensyms_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = xensyms_release
+};