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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 | #include <linux/syslog.h> | |
40 | ||
41 | #include "internal.h" | |
42 | ||
43 | #define PSTORE_NAMELEN 64 | |
44 | ||
45 | static DEFINE_SPINLOCK(allpstore_lock); | |
46 | static LIST_HEAD(allpstore); | |
47 | ||
48 | struct pstore_private { | |
49 | struct list_head list; | |
50 | struct pstore_info *psi; | |
51 | enum pstore_type_id type; | |
52 | u64 id; | |
53 | int count; | |
54 | ssize_t size; | |
55 | char data[]; | |
56 | }; | |
57 | ||
58 | struct pstore_ftrace_seq_data { | |
59 | const void *ptr; | |
60 | size_t off; | |
61 | size_t size; | |
62 | }; | |
63 | ||
64 | #define REC_SIZE sizeof(struct pstore_ftrace_record) | |
65 | ||
66 | static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos) | |
67 | { | |
68 | struct pstore_private *ps = s->private; | |
69 | struct pstore_ftrace_seq_data *data; | |
70 | ||
71 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
72 | if (!data) | |
73 | return NULL; | |
74 | ||
75 | data->off = ps->size % REC_SIZE; | |
76 | data->off += *pos * REC_SIZE; | |
77 | if (data->off + REC_SIZE > ps->size) { | |
78 | kfree(data); | |
79 | return NULL; | |
80 | } | |
81 | ||
82 | return data; | |
83 | ||
84 | } | |
85 | ||
86 | static void pstore_ftrace_seq_stop(struct seq_file *s, void *v) | |
87 | { | |
88 | kfree(v); | |
89 | } | |
90 | ||
91 | static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos) | |
92 | { | |
93 | struct pstore_private *ps = s->private; | |
94 | struct pstore_ftrace_seq_data *data = v; | |
95 | ||
96 | data->off += REC_SIZE; | |
97 | if (data->off + REC_SIZE > ps->size) | |
98 | return NULL; | |
99 | ||
100 | (*pos)++; | |
101 | return data; | |
102 | } | |
103 | ||
104 | static int pstore_ftrace_seq_show(struct seq_file *s, void *v) | |
105 | { | |
106 | struct pstore_private *ps = s->private; | |
107 | struct pstore_ftrace_seq_data *data = v; | |
108 | struct pstore_ftrace_record *rec = (void *)(ps->data + data->off); | |
109 | ||
110 | seq_printf(s, "%d %08lx %08lx %pf <- %pF\n", | |
111 | pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip, | |
112 | (void *)rec->ip, (void *)rec->parent_ip); | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | static const struct seq_operations pstore_ftrace_seq_ops = { | |
118 | .start = pstore_ftrace_seq_start, | |
119 | .next = pstore_ftrace_seq_next, | |
120 | .stop = pstore_ftrace_seq_stop, | |
121 | .show = pstore_ftrace_seq_show, | |
122 | }; | |
123 | ||
124 | static int pstore_check_syslog_permissions(struct pstore_private *ps) | |
125 | { | |
126 | switch (ps->type) { | |
127 | case PSTORE_TYPE_DMESG: | |
128 | case PSTORE_TYPE_CONSOLE: | |
129 | return check_syslog_permissions(SYSLOG_ACTION_READ_ALL, | |
130 | SYSLOG_FROM_READER); | |
131 | default: | |
132 | return 0; | |
133 | } | |
134 | } | |
135 | ||
136 | static ssize_t pstore_file_read(struct file *file, char __user *userbuf, | |
137 | size_t count, loff_t *ppos) | |
138 | { | |
139 | struct seq_file *sf = file->private_data; | |
140 | struct pstore_private *ps = sf->private; | |
141 | ||
142 | if (ps->type == PSTORE_TYPE_FTRACE) | |
143 | return seq_read(file, userbuf, count, ppos); | |
144 | return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size); | |
145 | } | |
146 | ||
147 | static int pstore_file_open(struct inode *inode, struct file *file) | |
148 | { | |
149 | struct pstore_private *ps = inode->i_private; | |
150 | struct seq_file *sf; | |
151 | int err; | |
152 | const struct seq_operations *sops = NULL; | |
153 | ||
154 | err = pstore_check_syslog_permissions(ps); | |
155 | if (err) | |
156 | return err; | |
157 | ||
158 | if (ps->type == PSTORE_TYPE_FTRACE) | |
159 | sops = &pstore_ftrace_seq_ops; | |
160 | ||
161 | err = seq_open(file, sops); | |
162 | if (err < 0) | |
163 | return err; | |
164 | ||
165 | sf = file->private_data; | |
166 | sf->private = ps; | |
167 | ||
168 | return 0; | |
169 | } | |
170 | ||
171 | static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence) | |
172 | { | |
173 | struct seq_file *sf = file->private_data; | |
174 | ||
175 | if (sf->op) | |
176 | return seq_lseek(file, off, whence); | |
177 | return default_llseek(file, off, whence); | |
178 | } | |
179 | ||
180 | static const struct file_operations pstore_file_operations = { | |
181 | .open = pstore_file_open, | |
182 | .read = pstore_file_read, | |
183 | .llseek = pstore_file_llseek, | |
184 | .release = seq_release, | |
185 | }; | |
186 | ||
187 | /* | |
188 | * When a file is unlinked from our file system we call the | |
189 | * platform driver to erase the record from persistent store. | |
190 | */ | |
191 | static int pstore_unlink(struct inode *dir, struct dentry *dentry) | |
192 | { | |
193 | struct pstore_private *p = d_inode(dentry)->i_private; | |
194 | int err; | |
195 | ||
196 | err = pstore_check_syslog_permissions(p); | |
197 | if (err) | |
198 | return err; | |
199 | ||
200 | if (p->psi->erase) | |
201 | p->psi->erase(p->type, p->id, p->count, | |
202 | d_inode(dentry)->i_ctime, p->psi); | |
203 | else | |
204 | return -EPERM; | |
205 | ||
206 | return simple_unlink(dir, dentry); | |
207 | } | |
208 | ||
209 | static void pstore_evict_inode(struct inode *inode) | |
210 | { | |
211 | struct pstore_private *p = inode->i_private; | |
212 | unsigned long flags; | |
213 | ||
214 | clear_inode(inode); | |
215 | if (p) { | |
216 | spin_lock_irqsave(&allpstore_lock, flags); | |
217 | list_del(&p->list); | |
218 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
219 | kfree(p); | |
220 | } | |
221 | } | |
222 | ||
223 | static const struct inode_operations pstore_dir_inode_operations = { | |
224 | .lookup = simple_lookup, | |
225 | .unlink = pstore_unlink, | |
226 | }; | |
227 | ||
228 | static struct inode *pstore_get_inode(struct super_block *sb) | |
229 | { | |
230 | struct inode *inode = new_inode(sb); | |
231 | if (inode) { | |
232 | inode->i_ino = get_next_ino(); | |
233 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
234 | } | |
235 | return inode; | |
236 | } | |
237 | ||
238 | enum { | |
239 | Opt_kmsg_bytes, Opt_err | |
240 | }; | |
241 | ||
242 | static const match_table_t tokens = { | |
243 | {Opt_kmsg_bytes, "kmsg_bytes=%u"}, | |
244 | {Opt_err, NULL} | |
245 | }; | |
246 | ||
247 | static void parse_options(char *options) | |
248 | { | |
249 | char *p; | |
250 | substring_t args[MAX_OPT_ARGS]; | |
251 | int option; | |
252 | ||
253 | if (!options) | |
254 | return; | |
255 | ||
256 | while ((p = strsep(&options, ",")) != NULL) { | |
257 | int token; | |
258 | ||
259 | if (!*p) | |
260 | continue; | |
261 | ||
262 | token = match_token(p, tokens, args); | |
263 | switch (token) { | |
264 | case Opt_kmsg_bytes: | |
265 | if (!match_int(&args[0], &option)) | |
266 | pstore_set_kmsg_bytes(option); | |
267 | break; | |
268 | } | |
269 | } | |
270 | } | |
271 | ||
272 | static int pstore_remount(struct super_block *sb, int *flags, char *data) | |
273 | { | |
274 | sync_filesystem(sb); | |
275 | parse_options(data); | |
276 | ||
277 | return 0; | |
278 | } | |
279 | ||
280 | static const struct super_operations pstore_ops = { | |
281 | .statfs = simple_statfs, | |
282 | .drop_inode = generic_delete_inode, | |
283 | .evict_inode = pstore_evict_inode, | |
284 | .remount_fs = pstore_remount, | |
285 | .show_options = generic_show_options, | |
286 | }; | |
287 | ||
288 | static struct super_block *pstore_sb; | |
289 | ||
290 | int pstore_is_mounted(void) | |
291 | { | |
292 | return pstore_sb != NULL; | |
293 | } | |
294 | ||
295 | /* | |
296 | * Make a regular file in the root directory of our file system. | |
297 | * Load it up with "size" bytes of data from "buf". | |
298 | * Set the mtime & ctime to the date that this record was originally stored. | |
299 | */ | |
300 | int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count, | |
301 | char *data, bool compressed, size_t size, | |
302 | struct timespec time, struct pstore_info *psi) | |
303 | { | |
304 | struct dentry *root = pstore_sb->s_root; | |
305 | struct dentry *dentry; | |
306 | struct inode *inode; | |
307 | int rc = 0; | |
308 | char name[PSTORE_NAMELEN]; | |
309 | struct pstore_private *private, *pos; | |
310 | unsigned long flags; | |
311 | ||
312 | spin_lock_irqsave(&allpstore_lock, flags); | |
313 | list_for_each_entry(pos, &allpstore, list) { | |
314 | if (pos->type == type && | |
315 | pos->id == id && | |
316 | pos->psi == psi) { | |
317 | rc = -EEXIST; | |
318 | break; | |
319 | } | |
320 | } | |
321 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
322 | if (rc) | |
323 | return rc; | |
324 | ||
325 | rc = -ENOMEM; | |
326 | inode = pstore_get_inode(pstore_sb); | |
327 | if (!inode) | |
328 | goto fail; | |
329 | inode->i_mode = S_IFREG | 0444; | |
330 | inode->i_fop = &pstore_file_operations; | |
331 | private = kmalloc(sizeof *private + size, GFP_KERNEL); | |
332 | if (!private) | |
333 | goto fail_alloc; | |
334 | private->type = type; | |
335 | private->id = id; | |
336 | private->count = count; | |
337 | private->psi = psi; | |
338 | ||
339 | switch (type) { | |
340 | case PSTORE_TYPE_DMESG: | |
341 | scnprintf(name, sizeof(name), "dmesg-%s-%lld%s", | |
342 | psname, id, compressed ? ".enc.z" : ""); | |
343 | break; | |
344 | case PSTORE_TYPE_CONSOLE: | |
345 | scnprintf(name, sizeof(name), "console-%s-%lld", psname, id); | |
346 | break; | |
347 | case PSTORE_TYPE_FTRACE: | |
348 | scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id); | |
349 | break; | |
350 | case PSTORE_TYPE_MCE: | |
351 | scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id); | |
352 | break; | |
353 | case PSTORE_TYPE_PPC_RTAS: | |
354 | scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id); | |
355 | break; | |
356 | case PSTORE_TYPE_PPC_OF: | |
357 | scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld", | |
358 | psname, id); | |
359 | break; | |
360 | case PSTORE_TYPE_PPC_COMMON: | |
361 | scnprintf(name, sizeof(name), "powerpc-common-%s-%lld", | |
362 | psname, id); | |
363 | break; | |
364 | case PSTORE_TYPE_PMSG: | |
365 | scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id); | |
366 | break; | |
367 | case PSTORE_TYPE_UNKNOWN: | |
368 | scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id); | |
369 | break; | |
370 | default: | |
371 | scnprintf(name, sizeof(name), "type%d-%s-%lld", | |
372 | type, psname, id); | |
373 | break; | |
374 | } | |
375 | ||
376 | mutex_lock(&d_inode(root)->i_mutex); | |
377 | ||
378 | dentry = d_alloc_name(root, name); | |
379 | if (!dentry) | |
380 | goto fail_lockedalloc; | |
381 | ||
382 | memcpy(private->data, data, size); | |
383 | inode->i_size = private->size = size; | |
384 | ||
385 | inode->i_private = private; | |
386 | ||
387 | if (time.tv_sec) | |
388 | inode->i_mtime = inode->i_ctime = time; | |
389 | ||
390 | d_add(dentry, inode); | |
391 | ||
392 | spin_lock_irqsave(&allpstore_lock, flags); | |
393 | list_add(&private->list, &allpstore); | |
394 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
395 | ||
396 | mutex_unlock(&d_inode(root)->i_mutex); | |
397 | ||
398 | return 0; | |
399 | ||
400 | fail_lockedalloc: | |
401 | mutex_unlock(&d_inode(root)->i_mutex); | |
402 | kfree(private); | |
403 | fail_alloc: | |
404 | iput(inode); | |
405 | ||
406 | fail: | |
407 | return rc; | |
408 | } | |
409 | ||
410 | static int pstore_fill_super(struct super_block *sb, void *data, int silent) | |
411 | { | |
412 | struct inode *inode; | |
413 | ||
414 | save_mount_options(sb, data); | |
415 | ||
416 | pstore_sb = sb; | |
417 | ||
418 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
419 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
420 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
421 | sb->s_magic = PSTOREFS_MAGIC; | |
422 | sb->s_op = &pstore_ops; | |
423 | sb->s_time_gran = 1; | |
424 | ||
425 | parse_options(data); | |
426 | ||
427 | inode = pstore_get_inode(sb); | |
428 | if (inode) { | |
429 | inode->i_mode = S_IFDIR | 0755; | |
430 | inode->i_op = &pstore_dir_inode_operations; | |
431 | inode->i_fop = &simple_dir_operations; | |
432 | inc_nlink(inode); | |
433 | } | |
434 | sb->s_root = d_make_root(inode); | |
435 | if (!sb->s_root) | |
436 | return -ENOMEM; | |
437 | ||
438 | pstore_get_records(0); | |
439 | ||
440 | return 0; | |
441 | } | |
442 | ||
443 | static struct dentry *pstore_mount(struct file_system_type *fs_type, | |
444 | int flags, const char *dev_name, void *data) | |
445 | { | |
446 | return mount_single(fs_type, flags, data, pstore_fill_super); | |
447 | } | |
448 | ||
449 | static void pstore_kill_sb(struct super_block *sb) | |
450 | { | |
451 | kill_litter_super(sb); | |
452 | pstore_sb = NULL; | |
453 | } | |
454 | ||
455 | static struct file_system_type pstore_fs_type = { | |
456 | .name = "pstore", | |
457 | .mount = pstore_mount, | |
458 | .kill_sb = pstore_kill_sb, | |
459 | }; | |
460 | ||
461 | static struct kobject *pstore_kobj; | |
462 | ||
463 | static int __init init_pstore_fs(void) | |
464 | { | |
465 | int err = 0; | |
466 | ||
467 | /* Create a convenient mount point for people to access pstore */ | |
468 | pstore_kobj = kobject_create_and_add("pstore", fs_kobj); | |
469 | if (!pstore_kobj) { | |
470 | err = -ENOMEM; | |
471 | goto out; | |
472 | } | |
473 | ||
474 | err = register_filesystem(&pstore_fs_type); | |
475 | if (err < 0) | |
476 | kobject_put(pstore_kobj); | |
477 | ||
478 | out: | |
479 | return err; | |
480 | } | |
481 | module_init(init_pstore_fs) | |
482 | ||
483 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); | |
484 | MODULE_LICENSE("GPL"); |