1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
/*
* Copyright (C) 2004 IBM Corporation
* Authors:
* Leendert van Doorn <leendert@watson.ibm.com>
* Dave Safford <safford@watson.ibm.com>
* Reiner Sailer <sailer@watson.ibm.com>
* Kylene Hall <kjhall@us.ibm.com>
*
* Copyright (C) 2013 Obsidian Research Corp
* Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
*
* Device file system interface to the TPM
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
*/
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/workqueue.h>
#include "tpm.h"
#include "tpm-dev.h"
static struct workqueue_struct *tpm_dev_wq;
static DEFINE_MUTEX(tpm_dev_wq_lock);
static void tpm_async_work(struct work_struct *work)
{
struct file_priv *priv =
container_of(work, struct file_priv, async_work);
ssize_t ret;
mutex_lock(&priv->buffer_mutex);
priv->command_enqueued = false;
ret = tpm_transmit(priv->chip, priv->space, priv->data_buffer,
sizeof(priv->data_buffer), 0);
tpm_put_ops(priv->chip);
if (ret > 0) {
priv->data_pending = ret;
mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
}
mutex_unlock(&priv->buffer_mutex);
wake_up_interruptible(&priv->async_wait);
}
static void user_reader_timeout(struct timer_list *t)
{
struct file_priv *priv = from_timer(priv, t, user_read_timer);
pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
task_tgid_nr(current));
schedule_work(&priv->timeout_work);
}
static void tpm_timeout_work(struct work_struct *work)
{
struct file_priv *priv = container_of(work, struct file_priv,
timeout_work);
mutex_lock(&priv->buffer_mutex);
priv->data_pending = 0;
memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
mutex_unlock(&priv->buffer_mutex);
wake_up_interruptible(&priv->async_wait);
}
void tpm_common_open(struct file *file, struct tpm_chip *chip,
struct file_priv *priv, struct tpm_space *space)
{
priv->chip = chip;
priv->space = space;
mutex_init(&priv->buffer_mutex);
timer_setup(&priv->user_read_timer, user_reader_timeout, 0);
INIT_WORK(&priv->timeout_work, tpm_timeout_work);
INIT_WORK(&priv->async_work, tpm_async_work);
init_waitqueue_head(&priv->async_wait);
file->private_data = priv;
}
ssize_t tpm_common_read(struct file *file, char __user *buf,
size_t size, loff_t *off)
{
struct file_priv *priv = file->private_data;
ssize_t ret_size = 0;
int rc;
del_singleshot_timer_sync(&priv->user_read_timer);
flush_work(&priv->timeout_work);
mutex_lock(&priv->buffer_mutex);
if (priv->data_pending) {
ret_size = min_t(ssize_t, size, priv->data_pending);
if (ret_size > 0) {
rc = copy_to_user(buf, priv->data_buffer, ret_size);
memset(priv->data_buffer, 0, priv->data_pending);
if (rc)
ret_size = -EFAULT;
}
priv->data_pending = 0;
}
mutex_unlock(&priv->buffer_mutex);
return ret_size;
}
ssize_t tpm_common_write(struct file *file, const char __user *buf,
size_t size, loff_t *off)
{
struct file_priv *priv = file->private_data;
int ret = 0;
if (size > TPM_BUFSIZE)
return -E2BIG;
mutex_lock(&priv->buffer_mutex);
/* Cannot perform a write until the read has cleared either via
* tpm_read or a user_read_timer timeout. This also prevents split
* buffered writes from blocking here.
*/
if (priv->data_pending != 0 || priv->command_enqueued) {
ret = -EBUSY;
goto out;
}
if (copy_from_user(priv->data_buffer, buf, size)) {
ret = -EFAULT;
goto out;
}
if (size < 6 ||
size < be32_to_cpu(*((__be32 *)(priv->data_buffer + 2)))) {
ret = -EINVAL;
goto out;
}
/* atomic tpm command send and result receive. We only hold the ops
* lock during this period so that the tpm can be unregistered even if
* the char dev is held open.
*/
if (tpm_try_get_ops(priv->chip)) {
ret = -EPIPE;
goto out;
}
/*
* If in nonblocking mode schedule an async job to send
* the command return the size.
* In case of error the err code will be returned in
* the subsequent read call.
*/
if (file->f_flags & O_NONBLOCK) {
priv->command_enqueued = true;
queue_work(tpm_dev_wq, &priv->async_work);
mutex_unlock(&priv->buffer_mutex);
return size;
}
ret = tpm_transmit(priv->chip, priv->space, priv->data_buffer,
sizeof(priv->data_buffer), 0);
tpm_put_ops(priv->chip);
if (ret > 0) {
priv->data_pending = ret;
mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
ret = size;
}
out:
mutex_unlock(&priv->buffer_mutex);
return ret;
}
__poll_t tpm_common_poll(struct file *file, poll_table *wait)
{
struct file_priv *priv = file->private_data;
__poll_t mask = 0;
poll_wait(file, &priv->async_wait, wait);
if (priv->data_pending)
mask = EPOLLIN | EPOLLRDNORM;
else
mask = EPOLLOUT | EPOLLWRNORM;
return mask;
}
/*
* Called on file close
*/
void tpm_common_release(struct file *file, struct file_priv *priv)
{
flush_work(&priv->async_work);
del_singleshot_timer_sync(&priv->user_read_timer);
flush_work(&priv->timeout_work);
file->private_data = NULL;
priv->data_pending = 0;
}
int __init tpm_dev_common_init(void)
{
tpm_dev_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
return !tpm_dev_wq ? -ENOMEM : 0;
}
void __exit tpm_dev_common_exit(void)
{
if (tpm_dev_wq) {
destroy_workqueue(tpm_dev_wq);
tpm_dev_wq = NULL;
}
}
|
