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
13static struct dentry *dbfs_dir;
14
15static 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
26static void hypfs_dbfs_data_free(struct hypfs_dbfs_data *data)
27{
28 data->dbfs_file->data_free(data->buf_free_ptr);
29 kfree(objp: data);
30}
31
32static 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(f: file)->i_private;
43 if (mutex_lock_interruptible(&df->lock))
44 return -ERESTARTSYS;
45
46 data = hypfs_dbfs_data_alloc(f: df);
47 if (!data) {
48 mutex_unlock(lock: &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(lock: &df->lock);
54 kfree(objp: data);
55 return rc;
56 }
57 mutex_unlock(lock: &df->lock);
58
59 rc = simple_read_from_buffer(to: buf, count: size, ppos, from: data->buf, available: data->size);
60 hypfs_dbfs_data_free(data);
61 return rc;
62}
63
64static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
65{
66 struct hypfs_dbfs_file *df = file_inode(f: file)->i_private;
67 long rc;
68
69 mutex_lock(&df->lock);
70 rc = df->unlocked_ioctl(file, cmd, arg);
71 mutex_unlock(lock: &df->lock);
72 return rc;
73}
74
75static const struct file_operations dbfs_ops_ioctl = {
76 .read = dbfs_read,
77 .unlocked_ioctl = dbfs_ioctl,
78};
79
80static const struct file_operations dbfs_ops = {
81 .read = dbfs_read,
82};
83
84void 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(what: 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
94void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
95{
96 debugfs_remove(dentry: df->dentry);
97}
98
99static int __init hypfs_dbfs_init(void)
100{
101 int rc = -ENODATA;
102
103 dbfs_dir = debugfs_create_dir(name: "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
116fail_hypfs_diag0c_exit:
117 hypfs_diag0c_exit();
118fail_hypfs_sprp_exit:
119 hypfs_sprp_exit();
120 hypfs_vm_exit();
121fail_hypfs_diag_exit:
122 hypfs_diag_exit();
123 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
124fail_dbfs_exit:
125 debugfs_remove(dentry: dbfs_dir);
126 return rc;
127}
128device_initcall(hypfs_dbfs_init)
129

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