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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2014 Google, Inc.
4 */
5
6#include <linux/cdev.h>
7#include <linux/device.h>
8#include <linux/fs.h>
9#include <linux/uaccess.h>
10#include "internal.h"
11
12static DEFINE_MUTEX(pmsg_lock);
13
14static ssize_t write_pmsg(struct file *file, const char __user *buf,
15 size_t count, loff_t *ppos)
16{
17 struct pstore_record record;
18 int ret;
19
20 if (!count)
21 return 0;
22
23 pstore_record_init(&record, psinfo);
24 record.type = PSTORE_TYPE_PMSG;
25 record.size = count;
26
27 /* check outside lock, page in any data. write_user also checks */
28 if (!access_ok(buf, count))
29 return -EFAULT;
30
31 mutex_lock(&pmsg_lock);
32 ret = psinfo->write_user(&record, buf);
33 mutex_unlock(&pmsg_lock);
34 return ret ? ret : count;
35}
36
37static const struct file_operations pmsg_fops = {
38 .owner = THIS_MODULE,
39 .llseek = noop_llseek,
40 .write = write_pmsg,
41};
42
43static struct class *pmsg_class;
44static int pmsg_major;
45#define PMSG_NAME "pmsg"
46#undef pr_fmt
47#define pr_fmt(fmt) PMSG_NAME ": " fmt
48
49static char *pmsg_devnode(struct device *dev, umode_t *mode)
50{
51 if (mode)
52 *mode = 0220;
53 return NULL;
54}
55
56void pstore_register_pmsg(void)
57{
58 struct device *pmsg_device;
59
60 pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops);
61 if (pmsg_major < 0) {
62 pr_err("register_chrdev failed\n");
63 goto err;
64 }
65
66 pmsg_class = class_create(THIS_MODULE, PMSG_NAME);
67 if (IS_ERR(pmsg_class)) {
68 pr_err("device class file already in use\n");
69 goto err_class;
70 }
71 pmsg_class->devnode = pmsg_devnode;
72
73 pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0),
74 NULL, "%s%d", PMSG_NAME, 0);
75 if (IS_ERR(pmsg_device)) {
76 pr_err("failed to create device\n");
77 goto err_device;
78 }
79 return;
80
81err_device:
82 class_destroy(pmsg_class);
83err_class:
84 unregister_chrdev(pmsg_major, PMSG_NAME);
85err:
86 return;
87}
88
89void pstore_unregister_pmsg(void)
90{
91 device_destroy(pmsg_class, MKDEV(pmsg_major, 0));
92 class_destroy(pmsg_class);
93 unregister_chrdev(pmsg_major, PMSG_NAME);
94}
1/*
2 * Copyright 2014 Google, Inc.
3 *
4 * This software is licensed under the terms of the GNU General Public
5 * License version 2, as published by the Free Software Foundation, and
6 * may be copied, distributed, and modified under those terms.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14#include <linux/cdev.h>
15#include <linux/device.h>
16#include <linux/fs.h>
17#include <linux/uaccess.h>
18#include <linux/vmalloc.h>
19#include "internal.h"
20
21static DEFINE_MUTEX(pmsg_lock);
22#define PMSG_MAX_BOUNCE_BUFFER_SIZE (2*PAGE_SIZE)
23
24static ssize_t write_pmsg(struct file *file, const char __user *buf,
25 size_t count, loff_t *ppos)
26{
27 size_t i, buffer_size;
28 char *buffer;
29
30 if (!count)
31 return 0;
32
33 if (!access_ok(VERIFY_READ, buf, count))
34 return -EFAULT;
35
36 buffer_size = count;
37 if (buffer_size > PMSG_MAX_BOUNCE_BUFFER_SIZE)
38 buffer_size = PMSG_MAX_BOUNCE_BUFFER_SIZE;
39 buffer = vmalloc(buffer_size);
40 if (!buffer)
41 return -ENOMEM;
42
43 mutex_lock(&pmsg_lock);
44 for (i = 0; i < count; ) {
45 size_t c = min(count - i, buffer_size);
46 u64 id;
47 long ret;
48
49 ret = __copy_from_user(buffer, buf + i, c);
50 if (unlikely(ret != 0)) {
51 mutex_unlock(&pmsg_lock);
52 vfree(buffer);
53 return -EFAULT;
54 }
55 psinfo->write_buf(PSTORE_TYPE_PMSG, 0, &id, 0, buffer, 0, c,
56 psinfo);
57
58 i += c;
59 }
60
61 mutex_unlock(&pmsg_lock);
62 vfree(buffer);
63 return count;
64}
65
66static const struct file_operations pmsg_fops = {
67 .owner = THIS_MODULE,
68 .llseek = noop_llseek,
69 .write = write_pmsg,
70};
71
72static struct class *pmsg_class;
73static int pmsg_major;
74#define PMSG_NAME "pmsg"
75#undef pr_fmt
76#define pr_fmt(fmt) PMSG_NAME ": " fmt
77
78static char *pmsg_devnode(struct device *dev, umode_t *mode)
79{
80 if (mode)
81 *mode = 0220;
82 return NULL;
83}
84
85void pstore_register_pmsg(void)
86{
87 struct device *pmsg_device;
88
89 pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops);
90 if (pmsg_major < 0) {
91 pr_err("register_chrdev failed\n");
92 goto err;
93 }
94
95 pmsg_class = class_create(THIS_MODULE, PMSG_NAME);
96 if (IS_ERR(pmsg_class)) {
97 pr_err("device class file already in use\n");
98 goto err_class;
99 }
100 pmsg_class->devnode = pmsg_devnode;
101
102 pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0),
103 NULL, "%s%d", PMSG_NAME, 0);
104 if (IS_ERR(pmsg_device)) {
105 pr_err("failed to create device\n");
106 goto err_device;
107 }
108 return;
109
110err_device:
111 class_destroy(pmsg_class);
112err_class:
113 unregister_chrdev(pmsg_major, PMSG_NAME);
114err:
115 return;
116}
117
118void pstore_unregister_pmsg(void)
119{
120 device_destroy(pmsg_class, MKDEV(pmsg_major, 0));
121 class_destroy(pmsg_class);
122 unregister_chrdev(pmsg_major, PMSG_NAME);
123}