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
hypfs_dbfs_data_alloc(struct hypfs_dbfs_file * f)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
hypfs_dbfs_data_free(struct hypfs_dbfs_data * data)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
dbfs_read(struct file * file,char __user * buf,size_t size,loff_t * ppos)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 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
dbfs_ioctl(struct file * file,unsigned int cmd,unsigned long arg)61 static 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
75 static const struct file_operations dbfs_ops = {
76 .read = dbfs_read,
77 .llseek = no_llseek,
78 .unlocked_ioctl = dbfs_ioctl,
79 };
80
hypfs_dbfs_create_file(struct hypfs_dbfs_file * df)81 void 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
hypfs_dbfs_remove_file(struct hypfs_dbfs_file * df)88 void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
89 {
90 debugfs_remove(df->dentry);
91 }
92
hypfs_dbfs_init(void)93 static 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
110 fail_hypfs_diag0c_exit:
111 hypfs_diag0c_exit();
112 fail_hypfs_sprp_exit:
113 hypfs_sprp_exit();
114 hypfs_vm_exit();
115 fail_hypfs_diag_exit:
116 hypfs_diag_exit();
117 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
118 fail_dbfs_exit:
119 debugfs_remove(dbfs_dir);
120 return rc;
121 }
122 device_initcall(hypfs_dbfs_init)
123