]>
git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - drivers/char/tpm/tpm-dev-common.c
461bf0b8a09473dbadc89b9259473dc36be2cd77
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(unsigned long ptr
)
27 struct file_priv
*priv
= (struct file_priv
*)ptr
;
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 atomic_set(&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 atomic_set(&priv
->data_pending
, 0);
50 mutex_init(&priv
->buffer_mutex
);
51 setup_timer(&priv
->user_read_timer
, user_reader_timeout
,
53 INIT_WORK(&priv
->work
, timeout_work
);
55 file
->private_data
= priv
;
58 ssize_t
tpm_common_read(struct file
*file
, char __user
*buf
,
59 size_t size
, loff_t
*off
)
61 struct file_priv
*priv
= file
->private_data
;
63 ssize_t orig_ret_size
;
66 del_singleshot_timer_sync(&priv
->user_read_timer
);
67 flush_work(&priv
->work
);
68 ret_size
= atomic_read(&priv
->data_pending
);
69 if (ret_size
> 0) { /* relay data */
70 orig_ret_size
= ret_size
;
74 mutex_lock(&priv
->buffer_mutex
);
75 rc
= copy_to_user(buf
, priv
->data_buffer
, ret_size
);
76 memset(priv
->data_buffer
, 0, orig_ret_size
);
80 mutex_unlock(&priv
->buffer_mutex
);
83 atomic_set(&priv
->data_pending
, 0);
88 ssize_t
tpm_common_write(struct file
*file
, const char __user
*buf
,
89 size_t size
, loff_t
*off
, struct tpm_space
*space
)
91 struct file_priv
*priv
= file
->private_data
;
92 size_t in_size
= size
;
95 /* Cannot perform a write until the read has cleared either via
96 * tpm_read or a user_read_timer timeout. This also prevents split
97 * buffered writes from blocking here.
99 if (atomic_read(&priv
->data_pending
) != 0)
102 if (in_size
> TPM_BUFSIZE
)
105 mutex_lock(&priv
->buffer_mutex
);
108 (priv
->data_buffer
, (void __user
*) buf
, in_size
)) {
109 mutex_unlock(&priv
->buffer_mutex
);
114 in_size
< be32_to_cpu(*((__be32
*) (priv
->data_buffer
+ 2)))) {
115 mutex_unlock(&priv
->buffer_mutex
);
119 /* atomic tpm command send and result receive. We only hold the ops
120 * lock during this period so that the tpm can be unregistered even if
121 * the char dev is held open.
123 if (tpm_try_get_ops(priv
->chip
)) {
124 mutex_unlock(&priv
->buffer_mutex
);
127 out_size
= tpm_transmit(priv
->chip
, space
, priv
->data_buffer
,
128 sizeof(priv
->data_buffer
), 0);
130 tpm_put_ops(priv
->chip
);
132 mutex_unlock(&priv
->buffer_mutex
);
136 atomic_set(&priv
->data_pending
, out_size
);
137 mutex_unlock(&priv
->buffer_mutex
);
139 /* Set a timeout by which the reader must come claim the result */
140 mod_timer(&priv
->user_read_timer
, jiffies
+ (120 * HZ
));
146 * Called on file close
148 void tpm_common_release(struct file
*file
, struct file_priv
*priv
)
150 del_singleshot_timer_sync(&priv
->user_read_timer
);
151 flush_work(&priv
->work
);
152 file
->private_data
= NULL
;
153 atomic_set(&priv
->data_pending
, 0);