blob: de73caf3cebc8955e1502de7eac4eee0218c3fe6 [file] [log] [blame]
Huang Ying2ff729d2010-08-12 11:55:17 +08001/*
2 * APEI Error Record Serialization Table debug support
3 *
4 * ERST is a way provided by APEI to save and retrieve hardware error
Lucas De Marchi58f87ed2010-09-07 12:49:45 -04005 * information to and from a persistent store. This file provide the
Huang Ying2ff729d2010-08-12 11:55:17 +08006 * debugging/testing support for ERST kernel support and firmware
7 * implementation.
8 *
9 * Copyright 2010 Intel Corp.
10 * Author: Huang Ying <ying.huang@intel.com>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License version
14 * 2 as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 */
25
26#include <linux/kernel.h>
27#include <linux/module.h>
28#include <linux/uaccess.h>
29#include <acpi/apei.h>
30#include <linux/miscdevice.h>
31
32#include "apei-internal.h"
33
34#define ERST_DBG_PFX "ERST DBG: "
35
36#define ERST_DBG_RECORD_LEN_MAX 4096
37
38static void *erst_dbg_buf;
39static unsigned int erst_dbg_buf_len;
40
41/* Prevent erst_dbg_read/write from being invoked concurrently */
42static DEFINE_MUTEX(erst_dbg_mutex);
43
44static int erst_dbg_open(struct inode *inode, struct file *file)
45{
46 if (erst_disable)
47 return -ENODEV;
48
49 return nonseekable_open(inode, file);
50}
51
52static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
53{
54 int rc;
55 u64 record_id;
56 u32 record_count;
57
58 switch (cmd) {
59 case APEI_ERST_CLEAR_RECORD:
60 rc = copy_from_user(&record_id, (void __user *)arg,
61 sizeof(record_id));
62 if (rc)
63 return -EFAULT;
64 return erst_clear(record_id);
65 case APEI_ERST_GET_RECORD_COUNT:
66 rc = erst_get_record_count();
67 if (rc < 0)
68 return rc;
69 record_count = rc;
70 rc = put_user(record_count, (u32 __user *)arg);
71 if (rc)
72 return rc;
73 return 0;
74 default:
75 return -ENOTTY;
76 }
77}
78
79static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf,
80 size_t usize, loff_t *off)
81{
82 int rc;
83 ssize_t len = 0;
84 u64 id;
85
86 if (*off != 0)
87 return -EINVAL;
88
89 if (mutex_lock_interruptible(&erst_dbg_mutex) != 0)
90 return -EINTR;
91
92retry_next:
93 rc = erst_get_next_record_id(&id);
94 if (rc)
95 goto out;
96 /* no more record */
97 if (id == APEI_ERST_INVALID_RECORD_ID)
98 goto out;
99retry:
100 rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
101 /* The record may be cleared by others, try read next record */
102 if (rc == -ENOENT)
103 goto retry_next;
104 if (rc < 0)
105 goto out;
106 if (len > ERST_DBG_RECORD_LEN_MAX) {
107 pr_warning(ERST_DBG_PFX
108 "Record (ID: 0x%llx) length is too long: %zd\n",
109 id, len);
110 rc = -EIO;
111 goto out;
112 }
113 if (len > erst_dbg_buf_len) {
Huang Ying23f124c2010-09-29 19:53:54 +0800114 void *p;
Huang Ying2ff729d2010-08-12 11:55:17 +0800115 rc = -ENOMEM;
Huang Ying23f124c2010-09-29 19:53:54 +0800116 p = kmalloc(len, GFP_KERNEL);
117 if (!p)
Huang Ying2ff729d2010-08-12 11:55:17 +0800118 goto out;
Huang Ying23f124c2010-09-29 19:53:54 +0800119 kfree(erst_dbg_buf);
120 erst_dbg_buf = p;
Huang Ying2ff729d2010-08-12 11:55:17 +0800121 erst_dbg_buf_len = len;
122 goto retry;
123 }
124
125 rc = -EINVAL;
126 if (len > usize)
127 goto out;
128
129 rc = -EFAULT;
130 if (copy_to_user(ubuf, erst_dbg_buf, len))
131 goto out;
132 rc = 0;
133out:
134 mutex_unlock(&erst_dbg_mutex);
135 return rc ? rc : len;
136}
137
138static ssize_t erst_dbg_write(struct file *filp, const char __user *ubuf,
139 size_t usize, loff_t *off)
140{
141 int rc;
142 struct cper_record_header *rcd;
143
144 if (!capable(CAP_SYS_ADMIN))
145 return -EPERM;
146
147 if (usize > ERST_DBG_RECORD_LEN_MAX) {
148 pr_err(ERST_DBG_PFX "Too long record to be written\n");
149 return -EINVAL;
150 }
151
152 if (mutex_lock_interruptible(&erst_dbg_mutex))
153 return -EINTR;
154 if (usize > erst_dbg_buf_len) {
Huang Ying23f124c2010-09-29 19:53:54 +0800155 void *p;
Huang Ying2ff729d2010-08-12 11:55:17 +0800156 rc = -ENOMEM;
Huang Ying23f124c2010-09-29 19:53:54 +0800157 p = kmalloc(usize, GFP_KERNEL);
158 if (!p)
Huang Ying2ff729d2010-08-12 11:55:17 +0800159 goto out;
Huang Ying23f124c2010-09-29 19:53:54 +0800160 kfree(erst_dbg_buf);
161 erst_dbg_buf = p;
Huang Ying2ff729d2010-08-12 11:55:17 +0800162 erst_dbg_buf_len = usize;
163 }
164 rc = copy_from_user(erst_dbg_buf, ubuf, usize);
165 if (rc) {
166 rc = -EFAULT;
167 goto out;
168 }
169 rcd = erst_dbg_buf;
170 rc = -EINVAL;
171 if (rcd->record_length != usize)
172 goto out;
173
174 rc = erst_write(erst_dbg_buf);
175
176out:
177 mutex_unlock(&erst_dbg_mutex);
178 return rc < 0 ? rc : usize;
179}
180
181static const struct file_operations erst_dbg_ops = {
182 .owner = THIS_MODULE,
183 .open = erst_dbg_open,
184 .read = erst_dbg_read,
185 .write = erst_dbg_write,
186 .unlocked_ioctl = erst_dbg_ioctl,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200187 .llseek = no_llseek,
Huang Ying2ff729d2010-08-12 11:55:17 +0800188};
189
190static struct miscdevice erst_dbg_dev = {
191 .minor = MISC_DYNAMIC_MINOR,
192 .name = "erst_dbg",
193 .fops = &erst_dbg_ops,
194};
195
196static __init int erst_dbg_init(void)
197{
198 return misc_register(&erst_dbg_dev);
199}
200
201static __exit void erst_dbg_exit(void)
202{
203 misc_deregister(&erst_dbg_dev);
204 kfree(erst_dbg_buf);
205}
206
207module_init(erst_dbg_init);
208module_exit(erst_dbg_exit);
209
210MODULE_AUTHOR("Huang Ying");
211MODULE_DESCRIPTION("APEI Error Record Serialization Table debug support");
212MODULE_LICENSE("GPL");