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
12 static struct dentry *dbfs_dir;
13
14 static 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
25 static 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
31 static 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 if (mutex_lock_interruptible(&df->lock))
43 return -ERESTARTSYS;
44
45 data = hypfs_dbfs_data_alloc(df);
46 if (!data) {
47 mutex_unlock(&df->lock);
48 return -ENOMEM;
49 }
50 rc = df->data_create(&data->buf, &data->buf_free_ptr, &data->size);
51 if (rc) {
52 mutex_unlock(&df->lock);
53 kfree(data);
54 return rc;
55 }
56 mutex_unlock(&df->lock);
57
58 rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
59 hypfs_dbfs_data_free(data);
60 return rc;
61 }
62
63 static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
64 {
65 struct hypfs_dbfs_file *df = file_inode(file)->i_private;
66 long rc;
67
68 mutex_lock(&df->lock);
69 if (df->unlocked_ioctl)
70 rc = df->unlocked_ioctl(file, cmd, arg);
71 else
72 rc = -ENOTTY;
73 mutex_unlock(&df->lock);
74 return rc;
75 }
76
77 static const struct file_operations dbfs_ops = {
78 .read = dbfs_read,
79 .llseek = no_llseek,
80 .unlocked_ioctl = dbfs_ioctl,
81 };
82
83 void hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
84 {
85 df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df,
86 &dbfs_ops);
87 mutex_init(&df->lock);
88 }
89
90 void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
91 {
92 debugfs_remove(df->dentry);
93 }
94
95 static int __init hypfs_dbfs_init(void)
96 {
97 int rc = -ENODATA;
98
99 dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
100 if (hypfs_diag_init())
101 goto fail_dbfs_exit;
102 if (hypfs_vm_init())
103 goto fail_hypfs_diag_exit;
104 hypfs_sprp_init();
105 if (hypfs_diag0c_init())
106 goto fail_hypfs_sprp_exit;
107 rc = hypfs_fs_init();
108 if (rc)
109 goto fail_hypfs_diag0c_exit;
110 return 0;
111
112 fail_hypfs_diag0c_exit:
113 hypfs_diag0c_exit();
114 fail_hypfs_sprp_exit:
115 hypfs_sprp_exit();
116 hypfs_vm_exit();
117 fail_hypfs_diag_exit:
118 hypfs_diag_exit();
119 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
120 fail_dbfs_exit:
121 debugfs_remove(dbfs_dir);
122 return rc;
123 }
124 device_initcall(hypfs_dbfs_init)
125
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