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/security.h>
10 #include <linux/slab.h>
11 #include "hypfs.h"
12
13 static struct dentry *dbfs_dir;
14
hypfs_dbfs_data_alloc(struct hypfs_dbfs_file * f)15 static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f)
16 {
17 struct hypfs_dbfs_data *data;
18
19 data = kmalloc(sizeof(*data), GFP_KERNEL);
20 if (!data)
21 return NULL;
22 data->dbfs_file = f;
23 return data;
24 }
25
hypfs_dbfs_data_free(struct hypfs_dbfs_data * data)26 static void hypfs_dbfs_data_free(struct hypfs_dbfs_data *data)
27 {
28 data->dbfs_file->data_free(data->buf_free_ptr);
29 kfree(data);
30 }
31
dbfs_read(struct file * file,char __user * buf,size_t size,loff_t * ppos)32 static ssize_t dbfs_read(struct file *file, char __user *buf,
33 size_t size, loff_t *ppos)
34 {
35 struct hypfs_dbfs_data *data;
36 struct hypfs_dbfs_file *df;
37 ssize_t rc;
38
39 if (*ppos != 0)
40 return 0;
41
42 df = file_inode(file)->i_private;
43 if (mutex_lock_interruptible(&df->lock))
44 return -ERESTARTSYS;
45
46 data = hypfs_dbfs_data_alloc(df);
47 if (!data) {
48 mutex_unlock(&df->lock);
49 return -ENOMEM;
50 }
51 rc = df->data_create(&data->buf, &data->buf_free_ptr, &data->size);
52 if (rc) {
53 mutex_unlock(&df->lock);
54 kfree(data);
55 return rc;
56 }
57 mutex_unlock(&df->lock);
58
59 rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
60 hypfs_dbfs_data_free(data);
61 return rc;
62 }
63
dbfs_ioctl(struct file * file,unsigned int cmd,unsigned long arg)64 static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
65 {
66 struct hypfs_dbfs_file *df = file_inode(file)->i_private;
67 long rc;
68
69 mutex_lock(&df->lock);
70 rc = df->unlocked_ioctl(file, cmd, arg);
71 mutex_unlock(&df->lock);
72 return rc;
73 }
74
75 static const struct file_operations dbfs_ops_ioctl = {
76 .read = dbfs_read,
77 .unlocked_ioctl = dbfs_ioctl,
78 };
79
80 static const struct file_operations dbfs_ops = {
81 .read = dbfs_read,
82 };
83
hypfs_dbfs_create_file(struct hypfs_dbfs_file * df)84 void hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
85 {
86 const struct file_operations *fops = &dbfs_ops;
87
88 if (df->unlocked_ioctl && !security_locked_down(LOCKDOWN_DEBUGFS))
89 fops = &dbfs_ops_ioctl;
90 df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df, fops);
91 mutex_init(&df->lock);
92 }
93
hypfs_dbfs_remove_file(struct hypfs_dbfs_file * df)94 void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
95 {
96 debugfs_remove(df->dentry);
97 }
98
hypfs_dbfs_init(void)99 static int __init hypfs_dbfs_init(void)
100 {
101 int rc = -ENODATA;
102
103 dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
104 if (hypfs_diag_init())
105 goto fail_dbfs_exit;
106 if (hypfs_vm_init())
107 goto fail_hypfs_diag_exit;
108 hypfs_sprp_init();
109 if (hypfs_diag0c_init())
110 goto fail_hypfs_sprp_exit;
111 rc = hypfs_fs_init();
112 if (rc)
113 goto fail_hypfs_diag0c_exit;
114 return 0;
115
116 fail_hypfs_diag0c_exit:
117 hypfs_diag0c_exit();
118 fail_hypfs_sprp_exit:
119 hypfs_sprp_exit();
120 hypfs_vm_exit();
121 fail_hypfs_diag_exit:
122 hypfs_diag_exit();
123 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
124 fail_dbfs_exit:
125 debugfs_remove(dbfs_dir);
126 return rc;
127 }
128 device_initcall(hypfs_dbfs_init)
129