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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/ramfs.h>
31#include <linux/parser.h>
32#include <linux/sched.h>
33#include <linux/magic.h>
34#include <linux/pstore.h>
35#include <linux/slab.h>
36#include <linux/spinlock.h>
37#include <linux/uaccess.h>
38
39#include "internal.h"
40
41#define PSTORE_NAMELEN 64
42
43static DEFINE_SPINLOCK(allpstore_lock);
44static LIST_HEAD(allpstore);
45
46struct pstore_private {
47 struct list_head list;
48 struct pstore_info *psi;
49 enum pstore_type_id type;
50 u64 id;
51 ssize_t size;
52 char data[];
53};
54
55static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
56 size_t count, loff_t *ppos)
57{
58 struct pstore_private *ps = file->private_data;
59
60 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
61}
62
63static const struct file_operations pstore_file_operations = {
64 .open = simple_open,
65 .read = pstore_file_read,
66 .llseek = default_llseek,
67};
68
69/*
70 * When a file is unlinked from our file system we call the
71 * platform driver to erase the record from persistent store.
72 */
73static int pstore_unlink(struct inode *dir, struct dentry *dentry)
74{
75 struct pstore_private *p = dentry->d_inode->i_private;
76
77 if (p->psi->erase)
78 p->psi->erase(p->type, p->id, p->psi);
79
80 return simple_unlink(dir, dentry);
81}
82
83static void pstore_evict_inode(struct inode *inode)
84{
85 struct pstore_private *p = inode->i_private;
86 unsigned long flags;
87
88 clear_inode(inode);
89 if (p) {
90 spin_lock_irqsave(&allpstore_lock, flags);
91 list_del(&p->list);
92 spin_unlock_irqrestore(&allpstore_lock, flags);
93 kfree(p);
94 }
95}
96
97static const struct inode_operations pstore_dir_inode_operations = {
98 .lookup = simple_lookup,
99 .unlink = pstore_unlink,
100};
101
102static struct inode *pstore_get_inode(struct super_block *sb)
103{
104 struct inode *inode = new_inode(sb);
105 if (inode) {
106 inode->i_ino = get_next_ino();
107 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
108 }
109 return inode;
110}
111
112enum {
113 Opt_kmsg_bytes, Opt_err
114};
115
116static const match_table_t tokens = {
117 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
118 {Opt_err, NULL}
119};
120
121static void parse_options(char *options)
122{
123 char *p;
124 substring_t args[MAX_OPT_ARGS];
125 int option;
126
127 if (!options)
128 return;
129
130 while ((p = strsep(&options, ",")) != NULL) {
131 int token;
132
133 if (!*p)
134 continue;
135
136 token = match_token(p, tokens, args);
137 switch (token) {
138 case Opt_kmsg_bytes:
139 if (!match_int(&args[0], &option))
140 pstore_set_kmsg_bytes(option);
141 break;
142 }
143 }
144}
145
146static int pstore_remount(struct super_block *sb, int *flags, char *data)
147{
148 parse_options(data);
149
150 return 0;
151}
152
153static const struct super_operations pstore_ops = {
154 .statfs = simple_statfs,
155 .drop_inode = generic_delete_inode,
156 .evict_inode = pstore_evict_inode,
157 .remount_fs = pstore_remount,
158 .show_options = generic_show_options,
159};
160
161static struct super_block *pstore_sb;
162
163int pstore_is_mounted(void)
164{
165 return pstore_sb != NULL;
166}
167
168/*
169 * Make a regular file in the root directory of our file system.
170 * Load it up with "size" bytes of data from "buf".
171 * Set the mtime & ctime to the date that this record was originally stored.
172 */
173int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
174 char *data, size_t size, struct timespec time,
175 struct pstore_info *psi)
176{
177 struct dentry *root = pstore_sb->s_root;
178 struct dentry *dentry;
179 struct inode *inode;
180 int rc = 0;
181 char name[PSTORE_NAMELEN];
182 struct pstore_private *private, *pos;
183 unsigned long flags;
184
185 spin_lock_irqsave(&allpstore_lock, flags);
186 list_for_each_entry(pos, &allpstore, list) {
187 if (pos->type == type &&
188 pos->id == id &&
189 pos->psi == psi) {
190 rc = -EEXIST;
191 break;
192 }
193 }
194 spin_unlock_irqrestore(&allpstore_lock, flags);
195 if (rc)
196 return rc;
197
198 rc = -ENOMEM;
199 inode = pstore_get_inode(pstore_sb);
200 if (!inode)
201 goto fail;
202 inode->i_mode = S_IFREG | 0444;
203 inode->i_fop = &pstore_file_operations;
204 private = kmalloc(sizeof *private + size, GFP_KERNEL);
205 if (!private)
206 goto fail_alloc;
207 private->type = type;
208 private->id = id;
209 private->psi = psi;
210
211 switch (type) {
212 case PSTORE_TYPE_DMESG:
213 sprintf(name, "dmesg-%s-%lld", psname, id);
214 break;
215 case PSTORE_TYPE_MCE:
216 sprintf(name, "mce-%s-%lld", psname, id);
217 break;
218 case PSTORE_TYPE_UNKNOWN:
219 sprintf(name, "unknown-%s-%lld", psname, id);
220 break;
221 default:
222 sprintf(name, "type%d-%s-%lld", type, psname, id);
223 break;
224 }
225
226 mutex_lock(&root->d_inode->i_mutex);
227
228 rc = -ENOSPC;
229 dentry = d_alloc_name(root, name);
230 if (IS_ERR(dentry))
231 goto fail_lockedalloc;
232
233 memcpy(private->data, data, size);
234 inode->i_size = private->size = size;
235
236 inode->i_private = private;
237
238 if (time.tv_sec)
239 inode->i_mtime = inode->i_ctime = time;
240
241 d_add(dentry, inode);
242
243 spin_lock_irqsave(&allpstore_lock, flags);
244 list_add(&private->list, &allpstore);
245 spin_unlock_irqrestore(&allpstore_lock, flags);
246
247 mutex_unlock(&root->d_inode->i_mutex);
248
249 return 0;
250
251fail_lockedalloc:
252 mutex_unlock(&root->d_inode->i_mutex);
253 kfree(private);
254fail_alloc:
255 iput(inode);
256
257fail:
258 return rc;
259}
260
261static int pstore_fill_super(struct super_block *sb, void *data, int silent)
262{
263 struct inode *inode;
264
265 save_mount_options(sb, data);
266
267 pstore_sb = sb;
268
269 sb->s_maxbytes = MAX_LFS_FILESIZE;
270 sb->s_blocksize = PAGE_CACHE_SIZE;
271 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
272 sb->s_magic = PSTOREFS_MAGIC;
273 sb->s_op = &pstore_ops;
274 sb->s_time_gran = 1;
275
276 parse_options(data);
277
278 inode = pstore_get_inode(sb);
279 if (inode) {
280 inode->i_mode = S_IFDIR | 0755;
281 inode->i_op = &pstore_dir_inode_operations;
282 inode->i_fop = &simple_dir_operations;
283 inc_nlink(inode);
284 }
285 sb->s_root = d_make_root(inode);
286 if (!sb->s_root)
287 return -ENOMEM;
288
289 pstore_get_records(0);
290
291 return 0;
292}
293
294static struct dentry *pstore_mount(struct file_system_type *fs_type,
295 int flags, const char *dev_name, void *data)
296{
297 return mount_single(fs_type, flags, data, pstore_fill_super);
298}
299
300static void pstore_kill_sb(struct super_block *sb)
301{
302 kill_litter_super(sb);
303 pstore_sb = NULL;
304}
305
306static struct file_system_type pstore_fs_type = {
307 .name = "pstore",
308 .mount = pstore_mount,
309 .kill_sb = pstore_kill_sb,
310};
311
312static int __init init_pstore_fs(void)
313{
314 return register_filesystem(&pstore_fs_type);
315}
316module_init(init_pstore_fs)
317
318MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
319MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Persistent Storage - ramfs parts.
4 *
5 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
6 */
7
8#include <linux/module.h>
9#include <linux/fs.h>
10#include <linux/fsnotify.h>
11#include <linux/pagemap.h>
12#include <linux/highmem.h>
13#include <linux/time.h>
14#include <linux/init.h>
15#include <linux/list.h>
16#include <linux/string.h>
17#include <linux/mount.h>
18#include <linux/seq_file.h>
19#include <linux/ramfs.h>
20#include <linux/parser.h>
21#include <linux/sched.h>
22#include <linux/magic.h>
23#include <linux/pstore.h>
24#include <linux/slab.h>
25#include <linux/uaccess.h>
26#include <linux/cleanup.h>
27
28#include "internal.h"
29
30#define PSTORE_NAMELEN 64
31
32static DEFINE_MUTEX(records_list_lock);
33static LIST_HEAD(records_list);
34
35static DEFINE_MUTEX(pstore_sb_lock);
36static struct super_block *pstore_sb;
37
38DEFINE_FREE(pstore_iput, struct inode *, if (_T) iput(_T))
39
40struct pstore_private {
41 struct list_head list;
42 struct dentry *dentry;
43 struct pstore_record *record;
44 size_t total_size;
45};
46
47struct pstore_ftrace_seq_data {
48 const void *ptr;
49 size_t off;
50 size_t size;
51};
52
53#define REC_SIZE sizeof(struct pstore_ftrace_record)
54
55static void free_pstore_private(struct pstore_private *private)
56{
57 if (!private)
58 return;
59 if (private->record) {
60 kvfree(private->record->buf);
61 kfree(private->record->priv);
62 kfree(private->record);
63 }
64 kfree(private);
65}
66DEFINE_FREE(pstore_private, struct pstore_private *, free_pstore_private(_T));
67
68static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
69{
70 struct pstore_private *ps = s->private;
71 struct pstore_ftrace_seq_data *data __free(kfree) = NULL;
72
73 data = kzalloc(sizeof(*data), GFP_KERNEL);
74 if (!data)
75 return NULL;
76
77 data->off = ps->total_size % REC_SIZE;
78 data->off += *pos * REC_SIZE;
79 if (data->off + REC_SIZE > ps->total_size)
80 return NULL;
81
82 return_ptr(data);
83}
84
85static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
86{
87 kfree(v);
88}
89
90static 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 (*pos)++;
96 data->off += REC_SIZE;
97 if (data->off + REC_SIZE > ps->total_size)
98 return NULL;
99
100 return data;
101}
102
103static 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;
108
109 if (!data)
110 return 0;
111
112 rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
113
114 seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %ps <- %pS\n",
115 pstore_ftrace_decode_cpu(rec),
116 pstore_ftrace_read_timestamp(rec),
117 rec->ip, rec->parent_ip, (void *)rec->ip,
118 (void *)rec->parent_ip);
119
120 return 0;
121}
122
123static const struct seq_operations pstore_ftrace_seq_ops = {
124 .start = pstore_ftrace_seq_start,
125 .next = pstore_ftrace_seq_next,
126 .stop = pstore_ftrace_seq_stop,
127 .show = pstore_ftrace_seq_show,
128};
129
130static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
131 size_t count, loff_t *ppos)
132{
133 struct seq_file *sf = file->private_data;
134 struct pstore_private *ps = sf->private;
135
136 if (ps->record->type == PSTORE_TYPE_FTRACE)
137 return seq_read(file, userbuf, count, ppos);
138 return simple_read_from_buffer(userbuf, count, ppos,
139 ps->record->buf, ps->total_size);
140}
141
142static int pstore_file_open(struct inode *inode, struct file *file)
143{
144 struct pstore_private *ps = inode->i_private;
145 struct seq_file *sf;
146 int err;
147 const struct seq_operations *sops = NULL;
148
149 if (ps->record->type == PSTORE_TYPE_FTRACE)
150 sops = &pstore_ftrace_seq_ops;
151
152 err = seq_open(file, sops);
153 if (err < 0)
154 return err;
155
156 sf = file->private_data;
157 sf->private = ps;
158
159 return 0;
160}
161
162static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
163{
164 struct seq_file *sf = file->private_data;
165
166 if (sf->op)
167 return seq_lseek(file, off, whence);
168 return default_llseek(file, off, whence);
169}
170
171static const struct file_operations pstore_file_operations = {
172 .open = pstore_file_open,
173 .read = pstore_file_read,
174 .llseek = pstore_file_llseek,
175 .release = seq_release,
176};
177
178/*
179 * When a file is unlinked from our file system we call the
180 * platform driver to erase the record from persistent store.
181 */
182static int pstore_unlink(struct inode *dir, struct dentry *dentry)
183{
184 struct pstore_private *p = d_inode(dentry)->i_private;
185 struct pstore_record *record = p->record;
186
187 if (!record->psi->erase)
188 return -EPERM;
189
190 /* Make sure we can't race while removing this file. */
191 scoped_guard(mutex, &records_list_lock) {
192 if (!list_empty(&p->list))
193 list_del_init(&p->list);
194 else
195 return -ENOENT;
196 p->dentry = NULL;
197 }
198
199 scoped_guard(mutex, &record->psi->read_mutex)
200 record->psi->erase(record);
201
202 return simple_unlink(dir, dentry);
203}
204
205static void pstore_evict_inode(struct inode *inode)
206{
207 struct pstore_private *p = inode->i_private;
208
209 clear_inode(inode);
210 free_pstore_private(p);
211}
212
213static const struct inode_operations pstore_dir_inode_operations = {
214 .lookup = simple_lookup,
215 .unlink = pstore_unlink,
216};
217
218static struct inode *pstore_get_inode(struct super_block *sb)
219{
220 struct inode *inode = new_inode(sb);
221 if (inode) {
222 inode->i_ino = get_next_ino();
223 simple_inode_init_ts(inode);
224 }
225 return inode;
226}
227
228enum {
229 Opt_kmsg_bytes, Opt_err
230};
231
232static const match_table_t tokens = {
233 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
234 {Opt_err, NULL}
235};
236
237static void parse_options(char *options)
238{
239 char *p;
240 substring_t args[MAX_OPT_ARGS];
241 int option;
242
243 if (!options)
244 return;
245
246 while ((p = strsep(&options, ",")) != NULL) {
247 int token;
248
249 if (!*p)
250 continue;
251
252 token = match_token(p, tokens, args);
253 switch (token) {
254 case Opt_kmsg_bytes:
255 if (!match_int(&args[0], &option))
256 pstore_set_kmsg_bytes(option);
257 break;
258 }
259 }
260}
261
262/*
263 * Display the mount options in /proc/mounts.
264 */
265static int pstore_show_options(struct seq_file *m, struct dentry *root)
266{
267 if (kmsg_bytes != CONFIG_PSTORE_DEFAULT_KMSG_BYTES)
268 seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
269 return 0;
270}
271
272static 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
280static 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 = pstore_show_options,
286};
287
288static struct dentry *psinfo_lock_root(void)
289{
290 struct dentry *root;
291
292 guard(mutex)(&pstore_sb_lock);
293 /*
294 * Having no backend is fine -- no records appear.
295 * Not being mounted is fine -- nothing to do.
296 */
297 if (!psinfo || !pstore_sb)
298 return NULL;
299
300 root = pstore_sb->s_root;
301 inode_lock(d_inode(root));
302
303 return root;
304}
305
306int pstore_put_backend_records(struct pstore_info *psi)
307{
308 struct pstore_private *pos, *tmp;
309 struct dentry *root;
310 int rc = 0;
311
312 root = psinfo_lock_root();
313 if (!root)
314 return 0;
315
316 scoped_guard(mutex, &records_list_lock) {
317 list_for_each_entry_safe(pos, tmp, &records_list, list) {
318 if (pos->record->psi == psi) {
319 list_del_init(&pos->list);
320 rc = simple_unlink(d_inode(root), pos->dentry);
321 if (WARN_ON(rc))
322 break;
323 d_drop(pos->dentry);
324 dput(pos->dentry);
325 pos->dentry = NULL;
326 }
327 }
328 }
329
330 inode_unlock(d_inode(root));
331
332 return rc;
333}
334
335/*
336 * Make a regular file in the root directory of our file system.
337 * Load it up with "size" bytes of data from "buf".
338 * Set the mtime & ctime to the date that this record was originally stored.
339 */
340int pstore_mkfile(struct dentry *root, struct pstore_record *record)
341{
342 struct dentry *dentry;
343 struct inode *inode __free(pstore_iput) = NULL;
344 char name[PSTORE_NAMELEN];
345 struct pstore_private *private __free(pstore_private) = NULL, *pos;
346 size_t size = record->size + record->ecc_notice_size;
347
348 if (WARN_ON(!inode_is_locked(d_inode(root))))
349 return -EINVAL;
350
351 guard(mutex)(&records_list_lock);
352
353 /* Skip records that are already present in the filesystem. */
354 list_for_each_entry(pos, &records_list, list) {
355 if (pos->record->type == record->type &&
356 pos->record->id == record->id &&
357 pos->record->psi == record->psi)
358 return -EEXIST;
359 }
360
361 inode = pstore_get_inode(root->d_sb);
362 if (!inode)
363 return -ENOMEM;
364 inode->i_mode = S_IFREG | 0444;
365 inode->i_fop = &pstore_file_operations;
366 scnprintf(name, sizeof(name), "%s-%s-%llu%s",
367 pstore_type_to_name(record->type),
368 record->psi->name, record->id,
369 record->compressed ? ".enc.z" : "");
370
371 private = kzalloc(sizeof(*private), GFP_KERNEL);
372 if (!private)
373 return -ENOMEM;
374
375 dentry = d_alloc_name(root, name);
376 if (!dentry)
377 return -ENOMEM;
378
379 private->dentry = dentry;
380 private->record = record;
381 inode->i_size = private->total_size = size;
382 inode->i_private = private;
383
384 if (record->time.tv_sec)
385 inode_set_mtime_to_ts(inode,
386 inode_set_ctime_to_ts(inode, record->time));
387
388 d_add(dentry, no_free_ptr(inode));
389
390 list_add(&(no_free_ptr(private))->list, &records_list);
391
392 return 0;
393}
394
395/*
396 * Read all the records from the persistent store. Create
397 * files in our filesystem. Don't warn about -EEXIST errors
398 * when we are re-scanning the backing store looking to add new
399 * error records.
400 */
401void pstore_get_records(int quiet)
402{
403 struct dentry *root;
404
405 root = psinfo_lock_root();
406 if (!root)
407 return;
408
409 pstore_get_backend_records(psinfo, root, quiet);
410 inode_unlock(d_inode(root));
411}
412
413static int pstore_fill_super(struct super_block *sb, void *data, int silent)
414{
415 struct inode *inode;
416
417 sb->s_maxbytes = MAX_LFS_FILESIZE;
418 sb->s_blocksize = PAGE_SIZE;
419 sb->s_blocksize_bits = PAGE_SHIFT;
420 sb->s_magic = PSTOREFS_MAGIC;
421 sb->s_op = &pstore_ops;
422 sb->s_time_gran = 1;
423
424 parse_options(data);
425
426 inode = pstore_get_inode(sb);
427 if (inode) {
428 inode->i_mode = S_IFDIR | 0750;
429 inode->i_op = &pstore_dir_inode_operations;
430 inode->i_fop = &simple_dir_operations;
431 inc_nlink(inode);
432 }
433 sb->s_root = d_make_root(inode);
434 if (!sb->s_root)
435 return -ENOMEM;
436
437 scoped_guard(mutex, &pstore_sb_lock)
438 pstore_sb = sb;
439
440 pstore_get_records(0);
441
442 return 0;
443}
444
445static struct dentry *pstore_mount(struct file_system_type *fs_type,
446 int flags, const char *dev_name, void *data)
447{
448 return mount_single(fs_type, flags, data, pstore_fill_super);
449}
450
451static void pstore_kill_sb(struct super_block *sb)
452{
453 guard(mutex)(&pstore_sb_lock);
454 WARN_ON(pstore_sb && pstore_sb != sb);
455
456 kill_litter_super(sb);
457 pstore_sb = NULL;
458
459 guard(mutex)(&records_list_lock);
460 INIT_LIST_HEAD(&records_list);
461}
462
463static struct file_system_type pstore_fs_type = {
464 .owner = THIS_MODULE,
465 .name = "pstore",
466 .mount = pstore_mount,
467 .kill_sb = pstore_kill_sb,
468};
469
470int __init pstore_init_fs(void)
471{
472 int err;
473
474 /* Create a convenient mount point for people to access pstore */
475 err = sysfs_create_mount_point(fs_kobj, "pstore");
476 if (err)
477 goto out;
478
479 err = register_filesystem(&pstore_fs_type);
480 if (err < 0)
481 sysfs_remove_mount_point(fs_kobj, "pstore");
482
483out:
484 return err;
485}
486
487void __exit pstore_exit_fs(void)
488{
489 unregister_filesystem(&pstore_fs_type);
490 sysfs_remove_mount_point(fs_kobj, "pstore");
491}