2 * Copyright (C) 2004 IBM Corporation
4 * Leendert van Doorn <leendert@watson.ibm.com>
5 * Dave Safford <safford@watson.ibm.com>
6 * Reiner Sailer <sailer@watson.ibm.com>
7 * Kylene Hall <kjhall@us.ibm.com>
9 * Copyright (C) 2013 Obsidian Research Corp
10 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
12 * Device file system interface to the TPM
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License as
16 * published by the Free Software Foundation, version 2 of the
20 #include <linux/slab.h>
21 #include <linux/uaccess.h>
25 static void user_reader_timeout(struct timer_list
*t
)
27 struct file_priv
*priv
= from_timer(priv
, t
, user_read_timer
);
29 pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
30 task_tgid_nr(current
));
32 schedule_work(&priv
->work
);
35 static void timeout_work(struct work_struct
*work
)
37 struct file_priv
*priv
= container_of(work
, struct file_priv
, work
);
39 mutex_lock(&priv
->buffer_mutex
);
40 priv
->data_pending
= 0;
41 memset(priv
->data_buffer
, 0, sizeof(priv
->data_buffer
));
42 mutex_unlock(&priv
->buffer_mutex
);
45 void tpm_common_open(struct file
*file
, struct tpm_chip
*chip
,
46 struct file_priv
*priv
)
49 mutex_init(&priv
->buffer_mutex
);
50 timer_setup(&priv
->user_read_timer
, user_reader_timeout
, 0);
51 INIT_WORK(&priv
->work
, timeout_work
);
53 file
->private_data
= priv
;
56 ssize_t
tpm_common_read(struct file
*file
, char __user
*buf
,
57 size_t size
, loff_t
*off
)
59 struct file_priv
*priv
= file
->private_data
;
63 del_singleshot_timer_sync(&priv
->user_read_timer
);
64 flush_work(&priv
->work
);
65 mutex_lock(&priv
->buffer_mutex
);
67 if (priv
->data_pending
) {
68 ret_size
= min_t(ssize_t
, size
, priv
->data_pending
);
69 rc
= copy_to_user(buf
, priv
->data_buffer
, ret_size
);
70 memset(priv
->data_buffer
, 0, priv
->data_pending
);
74 priv
->data_pending
= 0;
77 mutex_unlock(&priv
->buffer_mutex
);
81 ssize_t
tpm_common_write(struct file
*file
, const char __user
*buf
,
82 size_t size
, loff_t
*off
, struct tpm_space
*space
)
84 struct file_priv
*priv
= file
->private_data
;
85 size_t in_size
= size
;
88 if (in_size
> TPM_BUFSIZE
)
91 mutex_lock(&priv
->buffer_mutex
);
93 /* Cannot perform a write until the read has cleared either via
94 * tpm_read or a user_read_timer timeout. This also prevents split
95 * buffered writes from blocking here.
97 if (priv
->data_pending
!= 0) {
98 mutex_unlock(&priv
->buffer_mutex
);
103 (priv
->data_buffer
, (void __user
*) buf
, in_size
)) {
104 mutex_unlock(&priv
->buffer_mutex
);
109 in_size
< be32_to_cpu(*((__be32
*) (priv
->data_buffer
+ 2)))) {
110 mutex_unlock(&priv
->buffer_mutex
);
114 /* atomic tpm command send and result receive. We only hold the ops
115 * lock during this period so that the tpm can be unregistered even if
116 * the char dev is held open.
118 if (tpm_try_get_ops(priv
->chip
)) {
119 mutex_unlock(&priv
->buffer_mutex
);
122 out_size
= tpm_transmit(priv
->chip
, space
, priv
->data_buffer
,
123 sizeof(priv
->data_buffer
), 0);
125 tpm_put_ops(priv
->chip
);
127 mutex_unlock(&priv
->buffer_mutex
);
131 priv
->data_pending
= out_size
;
132 mutex_unlock(&priv
->buffer_mutex
);
134 /* Set a timeout by which the reader must come claim the result */
135 mod_timer(&priv
->user_read_timer
, jiffies
+ (120 * HZ
));
141 * Called on file close
143 void tpm_common_release(struct file
*file
, struct file_priv
*priv
)
145 del_singleshot_timer_sync(&priv
->user_read_timer
);
146 flush_work(&priv
->work
);
147 file
->private_data
= NULL
;
148 priv
->data_pending
= 0;