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1 | /* | |
2 | * Persistent Storage - ramfs parts. | |
3 | * | |
4 | * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com> | |
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> | |
27 | #include <linux/list.h> | |
28 | #include <linux/string.h> | |
29 | #include <linux/mount.h> | |
30 | #include <linux/seq_file.h> | |
31 | #include <linux/ramfs.h> | |
32 | #include <linux/parser.h> | |
33 | #include <linux/sched.h> | |
34 | #include <linux/magic.h> | |
35 | #include <linux/pstore.h> | |
36 | #include <linux/slab.h> | |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/uaccess.h> | |
39 | ||
40 | #include "internal.h" | |
41 | ||
42 | #define PSTORE_NAMELEN 64 | |
43 | ||
44 | static DEFINE_SPINLOCK(allpstore_lock); | |
45 | static LIST_HEAD(allpstore); | |
46 | ||
47 | struct pstore_private { | |
48 | struct list_head list; | |
49 | struct pstore_record *record; | |
50 | size_t total_size; | |
51 | }; | |
52 | ||
53 | struct pstore_ftrace_seq_data { | |
54 | const void *ptr; | |
55 | size_t off; | |
56 | size_t size; | |
57 | }; | |
58 | ||
59 | #define REC_SIZE sizeof(struct pstore_ftrace_record) | |
60 | ||
61 | static void free_pstore_private(struct pstore_private *private) | |
62 | { | |
63 | if (!private) | |
64 | return; | |
65 | if (private->record) { | |
66 | kfree(private->record->buf); | |
67 | kfree(private->record); | |
68 | } | |
69 | kfree(private); | |
70 | } | |
71 | ||
72 | static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos) | |
73 | { | |
74 | struct pstore_private *ps = s->private; | |
75 | struct pstore_ftrace_seq_data *data; | |
76 | ||
77 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
78 | if (!data) | |
79 | return NULL; | |
80 | ||
81 | data->off = ps->total_size % REC_SIZE; | |
82 | data->off += *pos * REC_SIZE; | |
83 | if (data->off + REC_SIZE > ps->total_size) { | |
84 | kfree(data); | |
85 | return NULL; | |
86 | } | |
87 | ||
88 | return data; | |
89 | ||
90 | } | |
91 | ||
92 | static void pstore_ftrace_seq_stop(struct seq_file *s, void *v) | |
93 | { | |
94 | kfree(v); | |
95 | } | |
96 | ||
97 | static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos) | |
98 | { | |
99 | struct pstore_private *ps = s->private; | |
100 | struct pstore_ftrace_seq_data *data = v; | |
101 | ||
102 | data->off += REC_SIZE; | |
103 | if (data->off + REC_SIZE > ps->total_size) | |
104 | return NULL; | |
105 | ||
106 | (*pos)++; | |
107 | return data; | |
108 | } | |
109 | ||
110 | static int pstore_ftrace_seq_show(struct seq_file *s, void *v) | |
111 | { | |
112 | struct pstore_private *ps = s->private; | |
113 | struct pstore_ftrace_seq_data *data = v; | |
114 | struct pstore_ftrace_record *rec; | |
115 | ||
116 | rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off); | |
117 | ||
118 | seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n", | |
119 | pstore_ftrace_decode_cpu(rec), | |
120 | pstore_ftrace_read_timestamp(rec), | |
121 | rec->ip, rec->parent_ip, (void *)rec->ip, | |
122 | (void *)rec->parent_ip); | |
123 | ||
124 | return 0; | |
125 | } | |
126 | ||
127 | static const struct seq_operations pstore_ftrace_seq_ops = { | |
128 | .start = pstore_ftrace_seq_start, | |
129 | .next = pstore_ftrace_seq_next, | |
130 | .stop = pstore_ftrace_seq_stop, | |
131 | .show = pstore_ftrace_seq_show, | |
132 | }; | |
133 | ||
134 | static ssize_t pstore_file_read(struct file *file, char __user *userbuf, | |
135 | size_t count, loff_t *ppos) | |
136 | { | |
137 | struct seq_file *sf = file->private_data; | |
138 | struct pstore_private *ps = sf->private; | |
139 | ||
140 | if (ps->record->type == PSTORE_TYPE_FTRACE) | |
141 | return seq_read(file, userbuf, count, ppos); | |
142 | return simple_read_from_buffer(userbuf, count, ppos, | |
143 | ps->record->buf, ps->total_size); | |
144 | } | |
145 | ||
146 | static int pstore_file_open(struct inode *inode, struct file *file) | |
147 | { | |
148 | struct pstore_private *ps = inode->i_private; | |
149 | struct seq_file *sf; | |
150 | int err; | |
151 | const struct seq_operations *sops = NULL; | |
152 | ||
153 | if (ps->record->type == PSTORE_TYPE_FTRACE) | |
154 | sops = &pstore_ftrace_seq_ops; | |
155 | ||
156 | err = seq_open(file, sops); | |
157 | if (err < 0) | |
158 | return err; | |
159 | ||
160 | sf = file->private_data; | |
161 | sf->private = ps; | |
162 | ||
163 | return 0; | |
164 | } | |
165 | ||
166 | static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence) | |
167 | { | |
168 | struct seq_file *sf = file->private_data; | |
169 | ||
170 | if (sf->op) | |
171 | return seq_lseek(file, off, whence); | |
172 | return default_llseek(file, off, whence); | |
173 | } | |
174 | ||
175 | static const struct file_operations pstore_file_operations = { | |
176 | .open = pstore_file_open, | |
177 | .read = pstore_file_read, | |
178 | .llseek = pstore_file_llseek, | |
179 | .release = seq_release, | |
180 | }; | |
181 | ||
182 | /* | |
183 | * When a file is unlinked from our file system we call the | |
184 | * platform driver to erase the record from persistent store. | |
185 | */ | |
186 | static int pstore_unlink(struct inode *dir, struct dentry *dentry) | |
187 | { | |
188 | struct pstore_private *p = d_inode(dentry)->i_private; | |
189 | struct pstore_record *record = p->record; | |
190 | ||
191 | if (!record->psi->erase) | |
192 | return -EPERM; | |
193 | ||
194 | mutex_lock(&record->psi->read_mutex); | |
195 | record->psi->erase(record); | |
196 | mutex_unlock(&record->psi->read_mutex); | |
197 | ||
198 | return simple_unlink(dir, dentry); | |
199 | } | |
200 | ||
201 | static void pstore_evict_inode(struct inode *inode) | |
202 | { | |
203 | struct pstore_private *p = inode->i_private; | |
204 | unsigned long flags; | |
205 | ||
206 | clear_inode(inode); | |
207 | if (p) { | |
208 | spin_lock_irqsave(&allpstore_lock, flags); | |
209 | list_del(&p->list); | |
210 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
211 | free_pstore_private(p); | |
212 | } | |
213 | } | |
214 | ||
215 | static const struct inode_operations pstore_dir_inode_operations = { | |
216 | .lookup = simple_lookup, | |
217 | .unlink = pstore_unlink, | |
218 | }; | |
219 | ||
220 | static struct inode *pstore_get_inode(struct super_block *sb) | |
221 | { | |
222 | struct inode *inode = new_inode(sb); | |
223 | if (inode) { | |
224 | inode->i_ino = get_next_ino(); | |
225 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); | |
226 | } | |
227 | return inode; | |
228 | } | |
229 | ||
230 | enum { | |
231 | Opt_kmsg_bytes, Opt_err | |
232 | }; | |
233 | ||
234 | static const match_table_t tokens = { | |
235 | {Opt_kmsg_bytes, "kmsg_bytes=%u"}, | |
236 | {Opt_err, NULL} | |
237 | }; | |
238 | ||
239 | static void parse_options(char *options) | |
240 | { | |
241 | char *p; | |
242 | substring_t args[MAX_OPT_ARGS]; | |
243 | int option; | |
244 | ||
245 | if (!options) | |
246 | return; | |
247 | ||
248 | while ((p = strsep(&options, ",")) != NULL) { | |
249 | int token; | |
250 | ||
251 | if (!*p) | |
252 | continue; | |
253 | ||
254 | token = match_token(p, tokens, args); | |
255 | switch (token) { | |
256 | case Opt_kmsg_bytes: | |
257 | if (!match_int(&args[0], &option)) | |
258 | pstore_set_kmsg_bytes(option); | |
259 | break; | |
260 | } | |
261 | } | |
262 | } | |
263 | ||
264 | /* | |
265 | * Display the mount options in /proc/mounts. | |
266 | */ | |
267 | static int pstore_show_options(struct seq_file *m, struct dentry *root) | |
268 | { | |
269 | if (kmsg_bytes != PSTORE_DEFAULT_KMSG_BYTES) | |
270 | seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes); | |
271 | return 0; | |
272 | } | |
273 | ||
274 | static int pstore_remount(struct super_block *sb, int *flags, char *data) | |
275 | { | |
276 | sync_filesystem(sb); | |
277 | parse_options(data); | |
278 | ||
279 | return 0; | |
280 | } | |
281 | ||
282 | static const struct super_operations pstore_ops = { | |
283 | .statfs = simple_statfs, | |
284 | .drop_inode = generic_delete_inode, | |
285 | .evict_inode = pstore_evict_inode, | |
286 | .remount_fs = pstore_remount, | |
287 | .show_options = pstore_show_options, | |
288 | }; | |
289 | ||
290 | static struct super_block *pstore_sb; | |
291 | ||
292 | bool pstore_is_mounted(void) | |
293 | { | |
294 | return pstore_sb != NULL; | |
295 | } | |
296 | ||
297 | /* | |
298 | * Make a regular file in the root directory of our file system. | |
299 | * Load it up with "size" bytes of data from "buf". | |
300 | * Set the mtime & ctime to the date that this record was originally stored. | |
301 | */ | |
302 | int pstore_mkfile(struct dentry *root, struct pstore_record *record) | |
303 | { | |
304 | struct dentry *dentry; | |
305 | struct inode *inode; | |
306 | int rc = 0; | |
307 | char name[PSTORE_NAMELEN]; | |
308 | struct pstore_private *private, *pos; | |
309 | unsigned long flags; | |
310 | size_t size = record->size + record->ecc_notice_size; | |
311 | ||
312 | WARN_ON(!inode_is_locked(d_inode(root))); | |
313 | ||
314 | spin_lock_irqsave(&allpstore_lock, flags); | |
315 | list_for_each_entry(pos, &allpstore, list) { | |
316 | if (pos->record->type == record->type && | |
317 | pos->record->id == record->id && | |
318 | pos->record->psi == record->psi) { | |
319 | rc = -EEXIST; | |
320 | break; | |
321 | } | |
322 | } | |
323 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
324 | if (rc) | |
325 | return rc; | |
326 | ||
327 | rc = -ENOMEM; | |
328 | inode = pstore_get_inode(root->d_sb); | |
329 | if (!inode) | |
330 | goto fail; | |
331 | inode->i_mode = S_IFREG | 0444; | |
332 | inode->i_fop = &pstore_file_operations; | |
333 | ||
334 | switch (record->type) { | |
335 | case PSTORE_TYPE_DMESG: | |
336 | scnprintf(name, sizeof(name), "dmesg-%s-%llu%s", | |
337 | record->psi->name, record->id, | |
338 | record->compressed ? ".enc.z" : ""); | |
339 | break; | |
340 | case PSTORE_TYPE_CONSOLE: | |
341 | scnprintf(name, sizeof(name), "console-%s-%llu", | |
342 | record->psi->name, record->id); | |
343 | break; | |
344 | case PSTORE_TYPE_FTRACE: | |
345 | scnprintf(name, sizeof(name), "ftrace-%s-%llu", | |
346 | record->psi->name, record->id); | |
347 | break; | |
348 | case PSTORE_TYPE_MCE: | |
349 | scnprintf(name, sizeof(name), "mce-%s-%llu", | |
350 | record->psi->name, record->id); | |
351 | break; | |
352 | case PSTORE_TYPE_PPC_RTAS: | |
353 | scnprintf(name, sizeof(name), "rtas-%s-%llu", | |
354 | record->psi->name, record->id); | |
355 | break; | |
356 | case PSTORE_TYPE_PPC_OF: | |
357 | scnprintf(name, sizeof(name), "powerpc-ofw-%s-%llu", | |
358 | record->psi->name, record->id); | |
359 | break; | |
360 | case PSTORE_TYPE_PPC_COMMON: | |
361 | scnprintf(name, sizeof(name), "powerpc-common-%s-%llu", | |
362 | record->psi->name, record->id); | |
363 | break; | |
364 | case PSTORE_TYPE_PMSG: | |
365 | scnprintf(name, sizeof(name), "pmsg-%s-%llu", | |
366 | record->psi->name, record->id); | |
367 | break; | |
368 | case PSTORE_TYPE_PPC_OPAL: | |
369 | scnprintf(name, sizeof(name), "powerpc-opal-%s-%llu", | |
370 | record->psi->name, record->id); | |
371 | break; | |
372 | case PSTORE_TYPE_UNKNOWN: | |
373 | scnprintf(name, sizeof(name), "unknown-%s-%llu", | |
374 | record->psi->name, record->id); | |
375 | break; | |
376 | default: | |
377 | scnprintf(name, sizeof(name), "type%d-%s-%llu", | |
378 | record->type, record->psi->name, record->id); | |
379 | break; | |
380 | } | |
381 | ||
382 | private = kzalloc(sizeof(*private), GFP_KERNEL); | |
383 | if (!private) | |
384 | goto fail_inode; | |
385 | ||
386 | dentry = d_alloc_name(root, name); | |
387 | if (!dentry) | |
388 | goto fail_private; | |
389 | ||
390 | private->record = record; | |
391 | inode->i_size = private->total_size = size; | |
392 | inode->i_private = private; | |
393 | ||
394 | if (record->time.tv_sec) | |
395 | inode->i_mtime = inode->i_ctime = record->time; | |
396 | ||
397 | d_add(dentry, inode); | |
398 | ||
399 | spin_lock_irqsave(&allpstore_lock, flags); | |
400 | list_add(&private->list, &allpstore); | |
401 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
402 | ||
403 | return 0; | |
404 | ||
405 | fail_private: | |
406 | free_pstore_private(private); | |
407 | fail_inode: | |
408 | iput(inode); | |
409 | ||
410 | fail: | |
411 | return rc; | |
412 | } | |
413 | ||
414 | /* | |
415 | * Read all the records from the persistent store. Create | |
416 | * files in our filesystem. Don't warn about -EEXIST errors | |
417 | * when we are re-scanning the backing store looking to add new | |
418 | * error records. | |
419 | */ | |
420 | void pstore_get_records(int quiet) | |
421 | { | |
422 | struct pstore_info *psi = psinfo; | |
423 | struct dentry *root; | |
424 | ||
425 | if (!psi || !pstore_sb) | |
426 | return; | |
427 | ||
428 | root = pstore_sb->s_root; | |
429 | ||
430 | inode_lock(d_inode(root)); | |
431 | pstore_get_backend_records(psi, root, quiet); | |
432 | inode_unlock(d_inode(root)); | |
433 | } | |
434 | ||
435 | static int pstore_fill_super(struct super_block *sb, void *data, int silent) | |
436 | { | |
437 | struct inode *inode; | |
438 | ||
439 | pstore_sb = sb; | |
440 | ||
441 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
442 | sb->s_blocksize = PAGE_SIZE; | |
443 | sb->s_blocksize_bits = PAGE_SHIFT; | |
444 | sb->s_magic = PSTOREFS_MAGIC; | |
445 | sb->s_op = &pstore_ops; | |
446 | sb->s_time_gran = 1; | |
447 | ||
448 | parse_options(data); | |
449 | ||
450 | inode = pstore_get_inode(sb); | |
451 | if (inode) { | |
452 | inode->i_mode = S_IFDIR | 0750; | |
453 | inode->i_op = &pstore_dir_inode_operations; | |
454 | inode->i_fop = &simple_dir_operations; | |
455 | inc_nlink(inode); | |
456 | } | |
457 | sb->s_root = d_make_root(inode); | |
458 | if (!sb->s_root) | |
459 | return -ENOMEM; | |
460 | ||
461 | pstore_get_records(0); | |
462 | ||
463 | return 0; | |
464 | } | |
465 | ||
466 | static struct dentry *pstore_mount(struct file_system_type *fs_type, | |
467 | int flags, const char *dev_name, void *data) | |
468 | { | |
469 | return mount_single(fs_type, flags, data, pstore_fill_super); | |
470 | } | |
471 | ||
472 | static void pstore_kill_sb(struct super_block *sb) | |
473 | { | |
474 | kill_litter_super(sb); | |
475 | pstore_sb = NULL; | |
476 | } | |
477 | ||
478 | static struct file_system_type pstore_fs_type = { | |
479 | .owner = THIS_MODULE, | |
480 | .name = "pstore", | |
481 | .mount = pstore_mount, | |
482 | .kill_sb = pstore_kill_sb, | |
483 | }; | |
484 | ||
485 | static int __init init_pstore_fs(void) | |
486 | { | |
487 | int err; | |
488 | ||
489 | /* Create a convenient mount point for people to access pstore */ | |
490 | err = sysfs_create_mount_point(fs_kobj, "pstore"); | |
491 | if (err) | |
492 | goto out; | |
493 | ||
494 | err = register_filesystem(&pstore_fs_type); | |
495 | if (err < 0) | |
496 | sysfs_remove_mount_point(fs_kobj, "pstore"); | |
497 | ||
498 | out: | |
499 | return err; | |
500 | } | |
501 | module_init(init_pstore_fs) | |
502 | ||
503 | static void __exit exit_pstore_fs(void) | |
504 | { | |
505 | unregister_filesystem(&pstore_fs_type); | |
506 | sysfs_remove_mount_point(fs_kobj, "pstore"); | |
507 | } | |
508 | module_exit(exit_pstore_fs) | |
509 | ||
510 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); | |
511 | MODULE_LICENSE("GPL"); |