summaryrefslogtreecommitdiffstats
path: root/drivers/acpi/apei/erst-dbg.c
blob: de73caf3cebc8955e1502de7eac4eee0218c3fe6 (plain)
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
/*
 * APEI Error Record Serialization Table debug support
 *
 * ERST is a way provided by APEI to save and retrieve hardware error
 * information to and from a persistent store. This file provide the
 * debugging/testing support for ERST kernel support and firmware
 * implementation.
 *
 * Copyright 2010 Intel Corp.
 *   Author: Huang Ying <ying.huang@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <acpi/apei.h>
#include <linux/miscdevice.h>

#include "apei-internal.h"

#define ERST_DBG_PFX			"ERST DBG: "

#define ERST_DBG_RECORD_LEN_MAX		4096

static void *erst_dbg_buf;
static unsigned int erst_dbg_buf_len;

/* Prevent erst_dbg_read/write from being invoked concurrently */
static DEFINE_MUTEX(erst_dbg_mutex);

static int erst_dbg_open(struct inode *inode, struct file *file)
{
	if (erst_disable)
		return -ENODEV;

	return nonseekable_open(inode, file);
}

static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
{
	int rc;
	u64 record_id;
	u32 record_count;

	switch (cmd) {
	case APEI_ERST_CLEAR_RECORD:
		rc = copy_from_user(&record_id, (void __user *)arg,
				    sizeof(record_id));
		if (rc)
			return -EFAULT;
		return erst_clear(record_id);
	case APEI_ERST_GET_RECORD_COUNT:
		rc = erst_get_record_count();
		if (rc < 0)
			return rc;
		record_count = rc;
		rc = put_user(record_count, (u32 __user *)arg);
		if (rc)
			return rc;
		return 0;
	default:
		return -ENOTTY;
	}
}

static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf,
			     size_t usize, loff_t *off)
{
	int rc;
	ssize_t len = 0;
	u64 id;

	if (*off != 0)
		return -EINVAL;

	if (mutex_lock_interruptible(&erst_dbg_mutex) != 0)
		return -EINTR;

retry_next:
	rc = erst_get_next_record_id(&id);
	if (rc)
		goto out;
	/* no more record */
	if (id == APEI_ERST_INVALID_RECORD_ID)
		goto out;
retry:
	rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
	/* The record may be cleared by others, try read next record */
	if (rc == -ENOENT)
		goto retry_next;
	if (rc < 0)
		goto out;
	if (len > ERST_DBG_RECORD_LEN_MAX) {
		pr_warning(ERST_DBG_PFX
			   "Record (ID: 0x%llx) length is too long: %zd\n",
			   id, len);
		rc = -EIO;
		goto out;
	}
	if (len > erst_dbg_buf_len) {
		void *p;
		rc = -ENOMEM;
		p = kmalloc(len, GFP_KERNEL);
		if (!p)
			goto out;
		kfree(erst_dbg_buf);
		erst_dbg_buf = p;
		erst_dbg_buf_len = len;
		goto retry;
	}

	rc = -EINVAL;
	if (len > usize)
		goto out;

	rc = -EFAULT;
	if (copy_to_user(ubuf, erst_dbg_buf, len))
		goto out;
	rc = 0;
out:
	mutex_unlock(&erst_dbg_mutex);
	return rc ? rc : len;
}

static ssize_t erst_dbg_write(struct file *filp, const char __user *ubuf,
			      size_t usize, loff_t *off)
{
	int rc;
	struct cper_record_header *rcd;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	if (usize > ERST_DBG_RECORD_LEN_MAX) {
		pr_err(ERST_DBG_PFX "Too long record to be written\n");
		return -EINVAL;
	}

	if (mutex_lock_interruptible(&erst_dbg_mutex))
		return -EINTR;
	if (usize > erst_dbg_buf_len) {
		void *p;
		rc = -ENOMEM;
		p = kmalloc(usize, GFP_KERNEL);
		if (!p)
			goto out;
		kfree(erst_dbg_buf);
		erst_dbg_buf = p;
		erst_dbg_buf_len = usize;
	}
	rc = copy_from_user(erst_dbg_buf, ubuf, usize);
	if (rc) {
		rc = -EFAULT;
		goto out;
	}
	rcd = erst_dbg_buf;
	rc = -EINVAL;
	if (rcd->record_length != usize)
		goto out;

	rc = erst_write(erst_dbg_buf);

out:
	mutex_unlock(&erst_dbg_mutex);
	return rc < 0 ? rc : usize;
}

static const struct file_operations erst_dbg_ops = {
	.owner		= THIS_MODULE,
	.open		= erst_dbg_open,
	.read		= erst_dbg_read,
	.write		= erst_dbg_write,
	.unlocked_ioctl	= erst_dbg_ioctl,
	.llseek		= no_llseek,
};

static struct miscdevice erst_dbg_dev = {
	.minor	= MISC_DYNAMIC_MINOR,
	.name	= "erst_dbg",
	.fops	= &erst_dbg_ops,
};

static __init int erst_dbg_init(void)
{
	return misc_register(&erst_dbg_dev);
}

static __exit void erst_dbg_exit(void)
{
	misc_deregister(&erst_dbg_dev);
	kfree(erst_dbg_buf);
}

module_init(erst_dbg_init);
module_exit(erst_dbg_exit);

MODULE_AUTHOR("Huang Ying");
MODULE_DESCRIPTION("APEI Error Record Serialization Table debug support");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud