tc-testing: updated pedit TDC tests
[linux-2.6-microblaze.git] / fs / pstore / pmsg.c
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
12 static DEFINE_MUTEX(pmsg_lock);
13
14 static 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
37 static const struct file_operations pmsg_fops = {
38         .owner          = THIS_MODULE,
39         .llseek         = noop_llseek,
40         .write          = write_pmsg,
41 };
42
43 static struct class *pmsg_class;
44 static int pmsg_major;
45 #define PMSG_NAME "pmsg"
46 #undef pr_fmt
47 #define pr_fmt(fmt) PMSG_NAME ": " fmt
48
49 static char *pmsg_devnode(struct device *dev, umode_t *mode)
50 {
51         if (mode)
52                 *mode = 0220;
53         return NULL;
54 }
55
56 void 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
81 err_device:
82         class_destroy(pmsg_class);
83 err_class:
84         unregister_chrdev(pmsg_major, PMSG_NAME);
85 err:
86         return;
87 }
88
89 void 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 }