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(size: 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(objp: 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(f: file)->i_private;
42 mutex_lock(&df->lock);
43 data = hypfs_dbfs_data_alloc(f: df);
44 if (!data) {
45 mutex_unlock(lock: &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(lock: &df->lock);
51 kfree(objp: data);
52 return rc;
53 }
54 mutex_unlock(lock: &df->lock);
55
56 rc = simple_read_from_buffer(to: buf, count: size, ppos, from: data->buf, available: 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(f: 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(lock: &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(name: df->name, mode: 0400, parent: dbfs_dir, data: df,
84 fops: &dbfs_ops);
85 mutex_init(&df->lock);
86}
87
88void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
89{
90 debugfs_remove(dentry: df->dentry);
91}
92
93static int __init hypfs_dbfs_init(void)
94{
95 int rc = -ENODATA;
96
97 dbfs_dir = debugfs_create_dir(name: "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(dentry: dbfs_dir);
120 return rc;
121}
122device_initcall(hypfs_dbfs_init)
123

source code of linux/arch/s390/hypfs/hypfs_dbfs.c