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ca01d6dd TL |
1 | /* |
2 | * Persistent Storage - ramfs parts. | |
3 | * | |
4 | * Copyright (C) 2010 Intel Corporation <[email protected]> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
19 | ||
20 | #include <linux/module.h> | |
21 | #include <linux/fs.h> | |
22 | #include <linux/fsnotify.h> | |
23 | #include <linux/pagemap.h> | |
24 | #include <linux/highmem.h> | |
25 | #include <linux/time.h> | |
26 | #include <linux/init.h> | |
6dda9266 | 27 | #include <linux/list.h> |
ca01d6dd TL |
28 | #include <linux/string.h> |
29 | #include <linux/mount.h> | |
060287b8 | 30 | #include <linux/seq_file.h> |
ca01d6dd | 31 | #include <linux/ramfs.h> |
366f7e7a | 32 | #include <linux/parser.h> |
ca01d6dd TL |
33 | #include <linux/sched.h> |
34 | #include <linux/magic.h> | |
35 | #include <linux/pstore.h> | |
36 | #include <linux/slab.h> | |
6dda9266 | 37 | #include <linux/spinlock.h> |
ca01d6dd TL |
38 | #include <linux/uaccess.h> |
39 | ||
40 | #include "internal.h" | |
41 | ||
42 | #define PSTORE_NAMELEN 64 | |
43 | ||
6dda9266 TL |
44 | static DEFINE_SPINLOCK(allpstore_lock); |
45 | static LIST_HEAD(allpstore); | |
46 | ||
ca01d6dd | 47 | struct pstore_private { |
6dda9266 | 48 | struct list_head list; |
638c1fd3 | 49 | struct pstore_info *psi; |
56280682 MG |
50 | enum pstore_type_id type; |
51 | u64 id; | |
755d4fe4 | 52 | int count; |
fbe0aa1f TL |
53 | ssize_t size; |
54 | char data[]; | |
ca01d6dd TL |
55 | }; |
56 | ||
060287b8 AV |
57 | struct pstore_ftrace_seq_data { |
58 | const void *ptr; | |
59 | size_t off; | |
60 | size_t size; | |
61 | }; | |
62 | ||
63 | #define REC_SIZE sizeof(struct pstore_ftrace_record) | |
64 | ||
65 | static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos) | |
66 | { | |
67 | struct pstore_private *ps = s->private; | |
68 | struct pstore_ftrace_seq_data *data; | |
69 | ||
70 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
71 | if (!data) | |
72 | return NULL; | |
73 | ||
74 | data->off = ps->size % REC_SIZE; | |
75 | data->off += *pos * REC_SIZE; | |
76 | if (data->off + REC_SIZE > ps->size) { | |
77 | kfree(data); | |
78 | return NULL; | |
79 | } | |
80 | ||
81 | return data; | |
82 | ||
83 | } | |
84 | ||
85 | static void pstore_ftrace_seq_stop(struct seq_file *s, void *v) | |
86 | { | |
87 | kfree(v); | |
88 | } | |
89 | ||
90 | static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos) | |
91 | { | |
92 | struct pstore_private *ps = s->private; | |
93 | struct pstore_ftrace_seq_data *data = v; | |
94 | ||
95 | data->off += REC_SIZE; | |
96 | if (data->off + REC_SIZE > ps->size) | |
97 | return NULL; | |
98 | ||
99 | (*pos)++; | |
100 | return data; | |
101 | } | |
102 | ||
103 | static int pstore_ftrace_seq_show(struct seq_file *s, void *v) | |
104 | { | |
105 | struct pstore_private *ps = s->private; | |
106 | struct pstore_ftrace_seq_data *data = v; | |
107 | struct pstore_ftrace_record *rec = (void *)(ps->data + data->off); | |
108 | ||
109 | seq_printf(s, "%d %08lx %08lx %pf <- %pF\n", | |
110 | pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip, | |
111 | (void *)rec->ip, (void *)rec->parent_ip); | |
112 | ||
113 | return 0; | |
114 | } | |
115 | ||
116 | static const struct seq_operations pstore_ftrace_seq_ops = { | |
117 | .start = pstore_ftrace_seq_start, | |
118 | .next = pstore_ftrace_seq_next, | |
119 | .stop = pstore_ftrace_seq_stop, | |
120 | .show = pstore_ftrace_seq_show, | |
121 | }; | |
122 | ||
fbe0aa1f TL |
123 | static ssize_t pstore_file_read(struct file *file, char __user *userbuf, |
124 | size_t count, loff_t *ppos) | |
125 | { | |
060287b8 AV |
126 | struct seq_file *sf = file->private_data; |
127 | struct pstore_private *ps = sf->private; | |
fbe0aa1f | 128 | |
060287b8 AV |
129 | if (ps->type == PSTORE_TYPE_FTRACE) |
130 | return seq_read(file, userbuf, count, ppos); | |
fbe0aa1f TL |
131 | return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size); |
132 | } | |
133 | ||
060287b8 AV |
134 | static int pstore_file_open(struct inode *inode, struct file *file) |
135 | { | |
136 | struct pstore_private *ps = inode->i_private; | |
137 | struct seq_file *sf; | |
138 | int err; | |
139 | const struct seq_operations *sops = NULL; | |
140 | ||
141 | if (ps->type == PSTORE_TYPE_FTRACE) | |
142 | sops = &pstore_ftrace_seq_ops; | |
143 | ||
144 | err = seq_open(file, sops); | |
145 | if (err < 0) | |
146 | return err; | |
147 | ||
148 | sf = file->private_data; | |
149 | sf->private = ps; | |
150 | ||
151 | return 0; | |
152 | } | |
153 | ||
965c8e59 | 154 | static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence) |
060287b8 AV |
155 | { |
156 | struct seq_file *sf = file->private_data; | |
157 | ||
158 | if (sf->op) | |
965c8e59 AM |
159 | return seq_lseek(file, off, whence); |
160 | return default_llseek(file, off, whence); | |
060287b8 AV |
161 | } |
162 | ||
fbe0aa1f | 163 | static const struct file_operations pstore_file_operations = { |
060287b8 AV |
164 | .open = pstore_file_open, |
165 | .read = pstore_file_read, | |
166 | .llseek = pstore_file_llseek, | |
167 | .release = seq_release, | |
fbe0aa1f | 168 | }; |
ca01d6dd TL |
169 | |
170 | /* | |
171 | * When a file is unlinked from our file system we call the | |
172 | * platform driver to erase the record from persistent store. | |
173 | */ | |
174 | static int pstore_unlink(struct inode *dir, struct dentry *dentry) | |
175 | { | |
176 | struct pstore_private *p = dentry->d_inode->i_private; | |
177 | ||
2174f6df | 178 | if (p->psi->erase) |
755d4fe4 SA |
179 | p->psi->erase(p->type, p->id, p->count, |
180 | dentry->d_inode->i_ctime, p->psi); | |
ca01d6dd TL |
181 | |
182 | return simple_unlink(dir, dentry); | |
183 | } | |
184 | ||
a872d510 TL |
185 | static void pstore_evict_inode(struct inode *inode) |
186 | { | |
6dda9266 TL |
187 | struct pstore_private *p = inode->i_private; |
188 | unsigned long flags; | |
189 | ||
dbd5768f | 190 | clear_inode(inode); |
6dda9266 TL |
191 | if (p) { |
192 | spin_lock_irqsave(&allpstore_lock, flags); | |
193 | list_del(&p->list); | |
194 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
195 | kfree(p); | |
196 | } | |
a872d510 TL |
197 | } |
198 | ||
ca01d6dd TL |
199 | static const struct inode_operations pstore_dir_inode_operations = { |
200 | .lookup = simple_lookup, | |
201 | .unlink = pstore_unlink, | |
202 | }; | |
203 | ||
22a71c30 | 204 | static struct inode *pstore_get_inode(struct super_block *sb) |
fbe0aa1f TL |
205 | { |
206 | struct inode *inode = new_inode(sb); | |
fbe0aa1f TL |
207 | if (inode) { |
208 | inode->i_ino = get_next_ino(); | |
fbe0aa1f | 209 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
fbe0aa1f TL |
210 | } |
211 | return inode; | |
212 | } | |
213 | ||
366f7e7a TL |
214 | enum { |
215 | Opt_kmsg_bytes, Opt_err | |
216 | }; | |
217 | ||
218 | static const match_table_t tokens = { | |
219 | {Opt_kmsg_bytes, "kmsg_bytes=%u"}, | |
220 | {Opt_err, NULL} | |
221 | }; | |
222 | ||
223 | static void parse_options(char *options) | |
224 | { | |
225 | char *p; | |
226 | substring_t args[MAX_OPT_ARGS]; | |
227 | int option; | |
228 | ||
229 | if (!options) | |
230 | return; | |
231 | ||
232 | while ((p = strsep(&options, ",")) != NULL) { | |
233 | int token; | |
234 | ||
235 | if (!*p) | |
236 | continue; | |
237 | ||
238 | token = match_token(p, tokens, args); | |
239 | switch (token) { | |
240 | case Opt_kmsg_bytes: | |
241 | if (!match_int(&args[0], &option)) | |
242 | pstore_set_kmsg_bytes(option); | |
243 | break; | |
244 | } | |
245 | } | |
246 | } | |
247 | ||
248 | static int pstore_remount(struct super_block *sb, int *flags, char *data) | |
249 | { | |
250 | parse_options(data); | |
251 | ||
252 | return 0; | |
253 | } | |
254 | ||
ca01d6dd TL |
255 | static const struct super_operations pstore_ops = { |
256 | .statfs = simple_statfs, | |
257 | .drop_inode = generic_delete_inode, | |
a872d510 | 258 | .evict_inode = pstore_evict_inode, |
366f7e7a | 259 | .remount_fs = pstore_remount, |
ca01d6dd TL |
260 | .show_options = generic_show_options, |
261 | }; | |
262 | ||
263 | static struct super_block *pstore_sb; | |
ca01d6dd TL |
264 | |
265 | int pstore_is_mounted(void) | |
266 | { | |
fbe0aa1f | 267 | return pstore_sb != NULL; |
ca01d6dd TL |
268 | } |
269 | ||
270 | /* | |
271 | * Make a regular file in the root directory of our file system. | |
272 | * Load it up with "size" bytes of data from "buf". | |
273 | * Set the mtime & ctime to the date that this record was originally stored. | |
274 | */ | |
755d4fe4 | 275 | int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count, |
638c1fd3 MG |
276 | char *data, size_t size, struct timespec time, |
277 | struct pstore_info *psi) | |
ca01d6dd TL |
278 | { |
279 | struct dentry *root = pstore_sb->s_root; | |
280 | struct dentry *dentry; | |
281 | struct inode *inode; | |
6dda9266 | 282 | int rc = 0; |
ca01d6dd | 283 | char name[PSTORE_NAMELEN]; |
6dda9266 TL |
284 | struct pstore_private *private, *pos; |
285 | unsigned long flags; | |
286 | ||
287 | spin_lock_irqsave(&allpstore_lock, flags); | |
288 | list_for_each_entry(pos, &allpstore, list) { | |
289 | if (pos->type == type && | |
290 | pos->id == id && | |
291 | pos->psi == psi) { | |
292 | rc = -EEXIST; | |
293 | break; | |
294 | } | |
295 | } | |
296 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
297 | if (rc) | |
298 | return rc; | |
ca01d6dd TL |
299 | |
300 | rc = -ENOMEM; | |
22a71c30 | 301 | inode = pstore_get_inode(pstore_sb); |
ca01d6dd TL |
302 | if (!inode) |
303 | goto fail; | |
22a71c30 AV |
304 | inode->i_mode = S_IFREG | 0444; |
305 | inode->i_fop = &pstore_file_operations; | |
fbe0aa1f | 306 | private = kmalloc(sizeof *private + size, GFP_KERNEL); |
ca01d6dd TL |
307 | if (!private) |
308 | goto fail_alloc; | |
56280682 | 309 | private->type = type; |
ca01d6dd | 310 | private->id = id; |
755d4fe4 | 311 | private->count = count; |
638c1fd3 | 312 | private->psi = psi; |
ca01d6dd TL |
313 | |
314 | switch (type) { | |
315 | case PSTORE_TYPE_DMESG: | |
316 | sprintf(name, "dmesg-%s-%lld", psname, id); | |
317 | break; | |
f29e5956 AV |
318 | case PSTORE_TYPE_CONSOLE: |
319 | sprintf(name, "console-%s", psname); | |
320 | break; | |
060287b8 AV |
321 | case PSTORE_TYPE_FTRACE: |
322 | sprintf(name, "ftrace-%s", psname); | |
323 | break; | |
ca01d6dd TL |
324 | case PSTORE_TYPE_MCE: |
325 | sprintf(name, "mce-%s-%lld", psname, id); | |
326 | break; | |
327 | case PSTORE_TYPE_UNKNOWN: | |
328 | sprintf(name, "unknown-%s-%lld", psname, id); | |
329 | break; | |
330 | default: | |
331 | sprintf(name, "type%d-%s-%lld", type, psname, id); | |
332 | break; | |
333 | } | |
334 | ||
335 | mutex_lock(&root->d_inode->i_mutex); | |
336 | ||
337 | rc = -ENOSPC; | |
338 | dentry = d_alloc_name(root, name); | |
339 | if (IS_ERR(dentry)) | |
340 | goto fail_lockedalloc; | |
341 | ||
fbe0aa1f TL |
342 | memcpy(private->data, data, size); |
343 | inode->i_size = private->size = size; | |
ca01d6dd TL |
344 | |
345 | inode->i_private = private; | |
346 | ||
347 | if (time.tv_sec) | |
348 | inode->i_mtime = inode->i_ctime = time; | |
349 | ||
fbe0aa1f | 350 | d_add(dentry, inode); |
ca01d6dd | 351 | |
6dda9266 TL |
352 | spin_lock_irqsave(&allpstore_lock, flags); |
353 | list_add(&private->list, &allpstore); | |
354 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
355 | ||
ca01d6dd | 356 | mutex_unlock(&root->d_inode->i_mutex); |
fbe0aa1f TL |
357 | |
358 | return 0; | |
ca01d6dd TL |
359 | |
360 | fail_lockedalloc: | |
361 | mutex_unlock(&root->d_inode->i_mutex); | |
362 | kfree(private); | |
363 | fail_alloc: | |
364 | iput(inode); | |
365 | ||
366 | fail: | |
367 | return rc; | |
368 | } | |
369 | ||
364ed2f4 | 370 | static int pstore_fill_super(struct super_block *sb, void *data, int silent) |
ca01d6dd | 371 | { |
318ceed0 | 372 | struct inode *inode; |
ca01d6dd TL |
373 | |
374 | save_mount_options(sb, data); | |
375 | ||
376 | pstore_sb = sb; | |
377 | ||
378 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
379 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
380 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
381 | sb->s_magic = PSTOREFS_MAGIC; | |
382 | sb->s_op = &pstore_ops; | |
383 | sb->s_time_gran = 1; | |
384 | ||
366f7e7a TL |
385 | parse_options(data); |
386 | ||
22a71c30 | 387 | inode = pstore_get_inode(sb); |
318ceed0 | 388 | if (inode) { |
22a71c30 | 389 | inode->i_mode = S_IFDIR | 0755; |
318ceed0 | 390 | inode->i_op = &pstore_dir_inode_operations; |
22a71c30 AV |
391 | inode->i_fop = &simple_dir_operations; |
392 | inc_nlink(inode); | |
ca01d6dd | 393 | } |
318ceed0 AV |
394 | sb->s_root = d_make_root(inode); |
395 | if (!sb->s_root) | |
396 | return -ENOMEM; | |
ca01d6dd | 397 | |
6dda9266 | 398 | pstore_get_records(0); |
ca01d6dd TL |
399 | |
400 | return 0; | |
ca01d6dd TL |
401 | } |
402 | ||
fbe0aa1f TL |
403 | static struct dentry *pstore_mount(struct file_system_type *fs_type, |
404 | int flags, const char *dev_name, void *data) | |
ca01d6dd | 405 | { |
fbe0aa1f | 406 | return mount_single(fs_type, flags, data, pstore_fill_super); |
ca01d6dd TL |
407 | } |
408 | ||
409 | static void pstore_kill_sb(struct super_block *sb) | |
410 | { | |
411 | kill_litter_super(sb); | |
412 | pstore_sb = NULL; | |
ca01d6dd TL |
413 | } |
414 | ||
415 | static struct file_system_type pstore_fs_type = { | |
416 | .name = "pstore", | |
fbe0aa1f | 417 | .mount = pstore_mount, |
ca01d6dd TL |
418 | .kill_sb = pstore_kill_sb, |
419 | }; | |
420 | ||
421 | static int __init init_pstore_fs(void) | |
422 | { | |
366f7e7a | 423 | return register_filesystem(&pstore_fs_type); |
ca01d6dd TL |
424 | } |
425 | module_init(init_pstore_fs) | |
426 | ||
427 | MODULE_AUTHOR("Tony Luck <[email protected]>"); | |
428 | MODULE_LICENSE("GPL"); |