1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Hypervisor filesystem for Linux on s390 - debugfs interface
4 *
5 * Copyright IBM Corp. 2010
6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
7 */
8
9#include <linux/slab.h>
10#include "hypfs.h"
11
12static struct dentry *dbfs_dir;
13
14static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f)
15{
16	struct hypfs_dbfs_data *data;
17
18	data = kmalloc(sizeof(*data), GFP_KERNEL);
19	if (!data)
20		return NULL;
21	data->dbfs_file = f;
22	return data;
23}
24
25static void hypfs_dbfs_data_free(struct hypfs_dbfs_data *data)
26{
27	data->dbfs_file->data_free(data->buf_free_ptr);
28	kfree(data);
29}
30
31static ssize_t dbfs_read(struct file *file, char __user *buf,
32			 size_t size, loff_t *ppos)
33{
34	struct hypfs_dbfs_data *data;
35	struct hypfs_dbfs_file *df;
36	ssize_t rc;
37
38	if (*ppos != 0)
39		return 0;
40
41	df = file_inode(file)->i_private;
42	mutex_lock(&df->lock);
43	data = hypfs_dbfs_data_alloc(df);
44	if (!data) {
45		mutex_unlock(&df->lock);
46		return -ENOMEM;
47	}
48	rc = df->data_create(&data->buf, &data->buf_free_ptr, &data->size);
49	if (rc) {
50		mutex_unlock(&df->lock);
51		kfree(data);
52		return rc;
53	}
54	mutex_unlock(&df->lock);
55
56	rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
57	hypfs_dbfs_data_free(data);
58	return rc;
59}
60
61static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
62{
63	struct hypfs_dbfs_file *df = file_inode(file)->i_private;
64	long rc;
65
66	mutex_lock(&df->lock);
67	if (df->unlocked_ioctl)
68		rc = df->unlocked_ioctl(file, cmd, arg);
69	else
70		rc = -ENOTTY;
71	mutex_unlock(&df->lock);
72	return rc;
73}
74
75static const struct file_operations dbfs_ops = {
76	.read		= dbfs_read,
77	.llseek		= no_llseek,
78	.unlocked_ioctl = dbfs_ioctl,
79};
80
81void hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
82{
83	df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df,
84					 &dbfs_ops);
85	mutex_init(&df->lock);
86}
87
88void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
89{
90	debugfs_remove(df->dentry);
91}
92
93static int __init hypfs_dbfs_init(void)
94{
95	int rc = -ENODATA;
96
97	dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
98	if (hypfs_diag_init())
99		goto fail_dbfs_exit;
100	if (hypfs_vm_init())
101		goto fail_hypfs_diag_exit;
102	hypfs_sprp_init();
103	if (hypfs_diag0c_init())
104		goto fail_hypfs_sprp_exit;
105	rc = hypfs_fs_init();
106	if (rc)
107		goto fail_hypfs_diag0c_exit;
108	return 0;
109
110fail_hypfs_diag0c_exit:
111	hypfs_diag0c_exit();
112fail_hypfs_sprp_exit:
113	hypfs_sprp_exit();
114	hypfs_vm_exit();
115fail_hypfs_diag_exit:
116	hypfs_diag_exit();
117	pr_err("Initialization of hypfs failed with rc=%i\n", rc);
118fail_dbfs_exit:
119	debugfs_remove(dbfs_dir);
120	return rc;
121}
122device_initcall(hypfs_dbfs_init)
123