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Commit | Line | Data |
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2ff729d5 HY |
1 | /* |
2 | * APEI Error Record Serialization Table debug support | |
3 | * | |
4 | * ERST is a way provided by APEI to save and retrieve hardware error | |
58f87ed0 | 5 | * information to and from a persistent store. This file provide the |
2ff729d5 HY |
6 | * 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. | |
2ff729d5 HY |
20 | */ |
21 | ||
22 | #include <linux/kernel.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/uaccess.h> | |
25 | #include <acpi/apei.h> | |
26 | #include <linux/miscdevice.h> | |
27 | ||
28 | #include "apei-internal.h" | |
29 | ||
30 | #define ERST_DBG_PFX "ERST DBG: " | |
31 | ||
d37afc50 | 32 | #define ERST_DBG_RECORD_LEN_MAX 0x4000 |
2ff729d5 HY |
33 | |
34 | static void *erst_dbg_buf; | |
35 | static unsigned int erst_dbg_buf_len; | |
36 | ||
37 | /* Prevent erst_dbg_read/write from being invoked concurrently */ | |
38 | static DEFINE_MUTEX(erst_dbg_mutex); | |
39 | ||
40 | static int erst_dbg_open(struct inode *inode, struct file *file) | |
41 | { | |
885b976f HY |
42 | int rc, *pos; |
43 | ||
2ff729d5 HY |
44 | if (erst_disable) |
45 | return -ENODEV; | |
46 | ||
885b976f HY |
47 | pos = (int *)&file->private_data; |
48 | ||
49 | rc = erst_get_record_id_begin(pos); | |
50 | if (rc) | |
51 | return rc; | |
52 | ||
2ff729d5 HY |
53 | return nonseekable_open(inode, file); |
54 | } | |
55 | ||
885b976f HY |
56 | static int erst_dbg_release(struct inode *inode, struct file *file) |
57 | { | |
58 | erst_get_record_id_end(); | |
59 | ||
60 | return 0; | |
61 | } | |
62 | ||
2ff729d5 HY |
63 | static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg) |
64 | { | |
65 | int rc; | |
66 | u64 record_id; | |
67 | u32 record_count; | |
68 | ||
69 | switch (cmd) { | |
70 | case APEI_ERST_CLEAR_RECORD: | |
71 | rc = copy_from_user(&record_id, (void __user *)arg, | |
72 | sizeof(record_id)); | |
73 | if (rc) | |
74 | return -EFAULT; | |
75 | return erst_clear(record_id); | |
76 | case APEI_ERST_GET_RECORD_COUNT: | |
77 | rc = erst_get_record_count(); | |
78 | if (rc < 0) | |
79 | return rc; | |
80 | record_count = rc; | |
81 | rc = put_user(record_count, (u32 __user *)arg); | |
82 | if (rc) | |
83 | return rc; | |
84 | return 0; | |
85 | default: | |
86 | return -ENOTTY; | |
87 | } | |
88 | } | |
89 | ||
90 | static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf, | |
91 | size_t usize, loff_t *off) | |
92 | { | |
885b976f | 93 | int rc, *pos; |
2ff729d5 HY |
94 | ssize_t len = 0; |
95 | u64 id; | |
96 | ||
885b976f | 97 | if (*off) |
2ff729d5 HY |
98 | return -EINVAL; |
99 | ||
100 | if (mutex_lock_interruptible(&erst_dbg_mutex) != 0) | |
101 | return -EINTR; | |
102 | ||
885b976f HY |
103 | pos = (int *)&filp->private_data; |
104 | ||
2ff729d5 | 105 | retry_next: |
885b976f | 106 | rc = erst_get_record_id_next(pos, &id); |
2ff729d5 HY |
107 | if (rc) |
108 | goto out; | |
109 | /* no more record */ | |
6780aa68 AH |
110 | if (id == APEI_ERST_INVALID_RECORD_ID) { |
111 | /* | |
112 | * If the persistent store is empty initially, the function | |
113 | * 'erst_read' below will return "-ENOENT" value. This causes | |
114 | * 'retry_next' label is entered again. The returned value | |
115 | * should be zero indicating the read operation is EOF. | |
116 | */ | |
117 | len = 0; | |
118 | ||
2ff729d5 | 119 | goto out; |
6780aa68 | 120 | } |
2ff729d5 HY |
121 | retry: |
122 | rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len); | |
123 | /* The record may be cleared by others, try read next record */ | |
124 | if (rc == -ENOENT) | |
125 | goto retry_next; | |
126 | if (rc < 0) | |
127 | goto out; | |
128 | if (len > ERST_DBG_RECORD_LEN_MAX) { | |
129 | pr_warning(ERST_DBG_PFX | |
130 | "Record (ID: 0x%llx) length is too long: %zd\n", | |
131 | id, len); | |
132 | rc = -EIO; | |
133 | goto out; | |
134 | } | |
135 | if (len > erst_dbg_buf_len) { | |
23f124ca | 136 | void *p; |
2ff729d5 | 137 | rc = -ENOMEM; |
23f124ca HY |
138 | p = kmalloc(len, GFP_KERNEL); |
139 | if (!p) | |
2ff729d5 | 140 | goto out; |
23f124ca HY |
141 | kfree(erst_dbg_buf); |
142 | erst_dbg_buf = p; | |
2ff729d5 HY |
143 | erst_dbg_buf_len = len; |
144 | goto retry; | |
145 | } | |
146 | ||
147 | rc = -EINVAL; | |
148 | if (len > usize) | |
149 | goto out; | |
150 | ||
151 | rc = -EFAULT; | |
152 | if (copy_to_user(ubuf, erst_dbg_buf, len)) | |
153 | goto out; | |
154 | rc = 0; | |
155 | out: | |
156 | mutex_unlock(&erst_dbg_mutex); | |
157 | return rc ? rc : len; | |
158 | } | |
159 | ||
160 | static ssize_t erst_dbg_write(struct file *filp, const char __user *ubuf, | |
161 | size_t usize, loff_t *off) | |
162 | { | |
163 | int rc; | |
164 | struct cper_record_header *rcd; | |
165 | ||
166 | if (!capable(CAP_SYS_ADMIN)) | |
167 | return -EPERM; | |
168 | ||
169 | if (usize > ERST_DBG_RECORD_LEN_MAX) { | |
170 | pr_err(ERST_DBG_PFX "Too long record to be written\n"); | |
171 | return -EINVAL; | |
172 | } | |
173 | ||
174 | if (mutex_lock_interruptible(&erst_dbg_mutex)) | |
175 | return -EINTR; | |
176 | if (usize > erst_dbg_buf_len) { | |
23f124ca | 177 | void *p; |
2ff729d5 | 178 | rc = -ENOMEM; |
23f124ca HY |
179 | p = kmalloc(usize, GFP_KERNEL); |
180 | if (!p) | |
2ff729d5 | 181 | goto out; |
23f124ca HY |
182 | kfree(erst_dbg_buf); |
183 | erst_dbg_buf = p; | |
2ff729d5 HY |
184 | erst_dbg_buf_len = usize; |
185 | } | |
186 | rc = copy_from_user(erst_dbg_buf, ubuf, usize); | |
187 | if (rc) { | |
188 | rc = -EFAULT; | |
189 | goto out; | |
190 | } | |
191 | rcd = erst_dbg_buf; | |
192 | rc = -EINVAL; | |
193 | if (rcd->record_length != usize) | |
194 | goto out; | |
195 | ||
196 | rc = erst_write(erst_dbg_buf); | |
197 | ||
198 | out: | |
199 | mutex_unlock(&erst_dbg_mutex); | |
200 | return rc < 0 ? rc : usize; | |
201 | } | |
202 | ||
203 | static const struct file_operations erst_dbg_ops = { | |
204 | .owner = THIS_MODULE, | |
205 | .open = erst_dbg_open, | |
885b976f | 206 | .release = erst_dbg_release, |
2ff729d5 HY |
207 | .read = erst_dbg_read, |
208 | .write = erst_dbg_write, | |
209 | .unlocked_ioctl = erst_dbg_ioctl, | |
6038f373 | 210 | .llseek = no_llseek, |
2ff729d5 HY |
211 | }; |
212 | ||
213 | static struct miscdevice erst_dbg_dev = { | |
214 | .minor = MISC_DYNAMIC_MINOR, | |
215 | .name = "erst_dbg", | |
216 | .fops = &erst_dbg_ops, | |
217 | }; | |
218 | ||
219 | static __init int erst_dbg_init(void) | |
220 | { | |
ca7cc511 HY |
221 | if (erst_disable) { |
222 | pr_info(ERST_DBG_PFX "ERST support is disabled.\n"); | |
223 | return -ENODEV; | |
224 | } | |
2ff729d5 HY |
225 | return misc_register(&erst_dbg_dev); |
226 | } | |
227 | ||
228 | static __exit void erst_dbg_exit(void) | |
229 | { | |
230 | misc_deregister(&erst_dbg_dev); | |
231 | kfree(erst_dbg_buf); | |
232 | } | |
233 | ||
234 | module_init(erst_dbg_init); | |
235 | module_exit(erst_dbg_exit); | |
236 | ||
237 | MODULE_AUTHOR("Huang Ying"); | |
238 | MODULE_DESCRIPTION("APEI Error Record Serialization Table debug support"); | |
239 | MODULE_LICENSE("GPL"); |