pstore: Add persistent function tracing
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / pstore / inode.c
CommitLineData
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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>
6dda9266 27#include <linux/list.h>
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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>
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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>
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38#include <linux/uaccess.h>
39
40#include "internal.h"
41
42#define PSTORE_NAMELEN 64
43
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44static DEFINE_SPINLOCK(allpstore_lock);
45static LIST_HEAD(allpstore);
46
ca01d6dd 47struct pstore_private {
6dda9266 48 struct list_head list;
638c1fd3 49 struct pstore_info *psi;
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50 enum pstore_type_id type;
51 u64 id;
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52 ssize_t size;
53 char data[];
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54};
55
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56struct pstore_ftrace_seq_data {
57 const void *ptr;
58 size_t off;
59 size_t size;
60};
61
62#define REC_SIZE sizeof(struct pstore_ftrace_record)
63
64static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
65{
66 struct pstore_private *ps = s->private;
67 struct pstore_ftrace_seq_data *data;
68
69 data = kzalloc(sizeof(*data), GFP_KERNEL);
70 if (!data)
71 return NULL;
72
73 data->off = ps->size % REC_SIZE;
74 data->off += *pos * REC_SIZE;
75 if (data->off + REC_SIZE > ps->size) {
76 kfree(data);
77 return NULL;
78 }
79
80 return data;
81
82}
83
84static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
85{
86 kfree(v);
87}
88
89static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
90{
91 struct pstore_private *ps = s->private;
92 struct pstore_ftrace_seq_data *data = v;
93
94 data->off += REC_SIZE;
95 if (data->off + REC_SIZE > ps->size)
96 return NULL;
97
98 (*pos)++;
99 return data;
100}
101
102static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
103{
104 struct pstore_private *ps = s->private;
105 struct pstore_ftrace_seq_data *data = v;
106 struct pstore_ftrace_record *rec = (void *)(ps->data + data->off);
107
108 seq_printf(s, "%d %08lx %08lx %pf <- %pF\n",
109 pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip,
110 (void *)rec->ip, (void *)rec->parent_ip);
111
112 return 0;
113}
114
115static const struct seq_operations pstore_ftrace_seq_ops = {
116 .start = pstore_ftrace_seq_start,
117 .next = pstore_ftrace_seq_next,
118 .stop = pstore_ftrace_seq_stop,
119 .show = pstore_ftrace_seq_show,
120};
121
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122static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
123 size_t count, loff_t *ppos)
124{
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125 struct seq_file *sf = file->private_data;
126 struct pstore_private *ps = sf->private;
fbe0aa1f 127
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128 if (ps->type == PSTORE_TYPE_FTRACE)
129 return seq_read(file, userbuf, count, ppos);
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130 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
131}
132
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133static int pstore_file_open(struct inode *inode, struct file *file)
134{
135 struct pstore_private *ps = inode->i_private;
136 struct seq_file *sf;
137 int err;
138 const struct seq_operations *sops = NULL;
139
140 if (ps->type == PSTORE_TYPE_FTRACE)
141 sops = &pstore_ftrace_seq_ops;
142
143 err = seq_open(file, sops);
144 if (err < 0)
145 return err;
146
147 sf = file->private_data;
148 sf->private = ps;
149
150 return 0;
151}
152
153static loff_t pstore_file_llseek(struct file *file, loff_t off, int origin)
154{
155 struct seq_file *sf = file->private_data;
156
157 if (sf->op)
158 return seq_lseek(file, off, origin);
159 return default_llseek(file, off, origin);
160}
161
fbe0aa1f 162static const struct file_operations pstore_file_operations = {
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163 .open = pstore_file_open,
164 .read = pstore_file_read,
165 .llseek = pstore_file_llseek,
166 .release = seq_release,
fbe0aa1f 167};
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168
169/*
170 * When a file is unlinked from our file system we call the
171 * platform driver to erase the record from persistent store.
172 */
173static int pstore_unlink(struct inode *dir, struct dentry *dentry)
174{
175 struct pstore_private *p = dentry->d_inode->i_private;
176
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177 if (p->psi->erase)
178 p->psi->erase(p->type, p->id, p->psi);
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179
180 return simple_unlink(dir, dentry);
181}
182
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183static void pstore_evict_inode(struct inode *inode)
184{
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185 struct pstore_private *p = inode->i_private;
186 unsigned long flags;
187
dbd5768f 188 clear_inode(inode);
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189 if (p) {
190 spin_lock_irqsave(&allpstore_lock, flags);
191 list_del(&p->list);
192 spin_unlock_irqrestore(&allpstore_lock, flags);
193 kfree(p);
194 }
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195}
196
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197static const struct inode_operations pstore_dir_inode_operations = {
198 .lookup = simple_lookup,
199 .unlink = pstore_unlink,
200};
201
22a71c30 202static struct inode *pstore_get_inode(struct super_block *sb)
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203{
204 struct inode *inode = new_inode(sb);
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205 if (inode) {
206 inode->i_ino = get_next_ino();
fbe0aa1f 207 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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208 }
209 return inode;
210}
211
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212enum {
213 Opt_kmsg_bytes, Opt_err
214};
215
216static const match_table_t tokens = {
217 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
218 {Opt_err, NULL}
219};
220
221static void parse_options(char *options)
222{
223 char *p;
224 substring_t args[MAX_OPT_ARGS];
225 int option;
226
227 if (!options)
228 return;
229
230 while ((p = strsep(&options, ",")) != NULL) {
231 int token;
232
233 if (!*p)
234 continue;
235
236 token = match_token(p, tokens, args);
237 switch (token) {
238 case Opt_kmsg_bytes:
239 if (!match_int(&args[0], &option))
240 pstore_set_kmsg_bytes(option);
241 break;
242 }
243 }
244}
245
246static int pstore_remount(struct super_block *sb, int *flags, char *data)
247{
248 parse_options(data);
249
250 return 0;
251}
252
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253static const struct super_operations pstore_ops = {
254 .statfs = simple_statfs,
255 .drop_inode = generic_delete_inode,
a872d510 256 .evict_inode = pstore_evict_inode,
366f7e7a 257 .remount_fs = pstore_remount,
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258 .show_options = generic_show_options,
259};
260
261static struct super_block *pstore_sb;
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262
263int pstore_is_mounted(void)
264{
fbe0aa1f 265 return pstore_sb != NULL;
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266}
267
268/*
269 * Make a regular file in the root directory of our file system.
270 * Load it up with "size" bytes of data from "buf".
271 * Set the mtime & ctime to the date that this record was originally stored.
272 */
273int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
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274 char *data, size_t size, struct timespec time,
275 struct pstore_info *psi)
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276{
277 struct dentry *root = pstore_sb->s_root;
278 struct dentry *dentry;
279 struct inode *inode;
6dda9266 280 int rc = 0;
ca01d6dd 281 char name[PSTORE_NAMELEN];
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282 struct pstore_private *private, *pos;
283 unsigned long flags;
284
285 spin_lock_irqsave(&allpstore_lock, flags);
286 list_for_each_entry(pos, &allpstore, list) {
287 if (pos->type == type &&
288 pos->id == id &&
289 pos->psi == psi) {
290 rc = -EEXIST;
291 break;
292 }
293 }
294 spin_unlock_irqrestore(&allpstore_lock, flags);
295 if (rc)
296 return rc;
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297
298 rc = -ENOMEM;
22a71c30 299 inode = pstore_get_inode(pstore_sb);
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300 if (!inode)
301 goto fail;
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AV
302 inode->i_mode = S_IFREG | 0444;
303 inode->i_fop = &pstore_file_operations;
fbe0aa1f 304 private = kmalloc(sizeof *private + size, GFP_KERNEL);
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305 if (!private)
306 goto fail_alloc;
56280682 307 private->type = type;
ca01d6dd 308 private->id = id;
638c1fd3 309 private->psi = psi;
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310
311 switch (type) {
312 case PSTORE_TYPE_DMESG:
313 sprintf(name, "dmesg-%s-%lld", psname, id);
314 break;
f29e5956
AV
315 case PSTORE_TYPE_CONSOLE:
316 sprintf(name, "console-%s", psname);
317 break;
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AV
318 case PSTORE_TYPE_FTRACE:
319 sprintf(name, "ftrace-%s", psname);
320 break;
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321 case PSTORE_TYPE_MCE:
322 sprintf(name, "mce-%s-%lld", psname, id);
323 break;
324 case PSTORE_TYPE_UNKNOWN:
325 sprintf(name, "unknown-%s-%lld", psname, id);
326 break;
327 default:
328 sprintf(name, "type%d-%s-%lld", type, psname, id);
329 break;
330 }
331
332 mutex_lock(&root->d_inode->i_mutex);
333
334 rc = -ENOSPC;
335 dentry = d_alloc_name(root, name);
336 if (IS_ERR(dentry))
337 goto fail_lockedalloc;
338
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339 memcpy(private->data, data, size);
340 inode->i_size = private->size = size;
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341
342 inode->i_private = private;
343
344 if (time.tv_sec)
345 inode->i_mtime = inode->i_ctime = time;
346
fbe0aa1f 347 d_add(dentry, inode);
ca01d6dd 348
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349 spin_lock_irqsave(&allpstore_lock, flags);
350 list_add(&private->list, &allpstore);
351 spin_unlock_irqrestore(&allpstore_lock, flags);
352
ca01d6dd 353 mutex_unlock(&root->d_inode->i_mutex);
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354
355 return 0;
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356
357fail_lockedalloc:
358 mutex_unlock(&root->d_inode->i_mutex);
359 kfree(private);
360fail_alloc:
361 iput(inode);
362
363fail:
364 return rc;
365}
366
364ed2f4 367static int pstore_fill_super(struct super_block *sb, void *data, int silent)
ca01d6dd 368{
318ceed0 369 struct inode *inode;
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370
371 save_mount_options(sb, data);
372
373 pstore_sb = sb;
374
375 sb->s_maxbytes = MAX_LFS_FILESIZE;
376 sb->s_blocksize = PAGE_CACHE_SIZE;
377 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
378 sb->s_magic = PSTOREFS_MAGIC;
379 sb->s_op = &pstore_ops;
380 sb->s_time_gran = 1;
381
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382 parse_options(data);
383
22a71c30 384 inode = pstore_get_inode(sb);
318ceed0 385 if (inode) {
22a71c30 386 inode->i_mode = S_IFDIR | 0755;
318ceed0 387 inode->i_op = &pstore_dir_inode_operations;
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AV
388 inode->i_fop = &simple_dir_operations;
389 inc_nlink(inode);
ca01d6dd 390 }
318ceed0
AV
391 sb->s_root = d_make_root(inode);
392 if (!sb->s_root)
393 return -ENOMEM;
ca01d6dd 394
6dda9266 395 pstore_get_records(0);
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396
397 return 0;
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398}
399
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400static struct dentry *pstore_mount(struct file_system_type *fs_type,
401 int flags, const char *dev_name, void *data)
ca01d6dd 402{
fbe0aa1f 403 return mount_single(fs_type, flags, data, pstore_fill_super);
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404}
405
406static void pstore_kill_sb(struct super_block *sb)
407{
408 kill_litter_super(sb);
409 pstore_sb = NULL;
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410}
411
412static struct file_system_type pstore_fs_type = {
413 .name = "pstore",
fbe0aa1f 414 .mount = pstore_mount,
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415 .kill_sb = pstore_kill_sb,
416};
417
418static int __init init_pstore_fs(void)
419{
366f7e7a 420 return register_filesystem(&pstore_fs_type);
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421}
422module_init(init_pstore_fs)
423
424MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
425MODULE_LICENSE("GPL");