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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
45static DEFINE_SPINLOCK(allpstore_lock);
46static LIST_HEAD(allpstore);
47
48struct 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
58struct 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
66static 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
86static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
87{
88 kfree(v);
89}
90
91static 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
104static 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, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n",
111 pstore_ftrace_decode_cpu(rec),
112 pstore_ftrace_read_timestamp(rec),
113 rec->ip, rec->parent_ip, (void *)rec->ip,
114 (void *)rec->parent_ip);
115
116 return 0;
117}
118
119static const struct seq_operations pstore_ftrace_seq_ops = {
120 .start = pstore_ftrace_seq_start,
121 .next = pstore_ftrace_seq_next,
122 .stop = pstore_ftrace_seq_stop,
123 .show = pstore_ftrace_seq_show,
124};
125
126static int pstore_check_syslog_permissions(struct pstore_private *ps)
127{
128 switch (ps->type) {
129 case PSTORE_TYPE_DMESG:
130 case PSTORE_TYPE_CONSOLE:
131 return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
132 SYSLOG_FROM_READER);
133 default:
134 return 0;
135 }
136}
137
138static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
139 size_t count, loff_t *ppos)
140{
141 struct seq_file *sf = file->private_data;
142 struct pstore_private *ps = sf->private;
143
144 if (ps->type == PSTORE_TYPE_FTRACE)
145 return seq_read(file, userbuf, count, ppos);
146 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
147}
148
149static int pstore_file_open(struct inode *inode, struct file *file)
150{
151 struct pstore_private *ps = inode->i_private;
152 struct seq_file *sf;
153 int err;
154 const struct seq_operations *sops = NULL;
155
156 err = pstore_check_syslog_permissions(ps);
157 if (err)
158 return err;
159
160 if (ps->type == PSTORE_TYPE_FTRACE)
161 sops = &pstore_ftrace_seq_ops;
162
163 err = seq_open(file, sops);
164 if (err < 0)
165 return err;
166
167 sf = file->private_data;
168 sf->private = ps;
169
170 return 0;
171}
172
173static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
174{
175 struct seq_file *sf = file->private_data;
176
177 if (sf->op)
178 return seq_lseek(file, off, whence);
179 return default_llseek(file, off, whence);
180}
181
182static const struct file_operations pstore_file_operations = {
183 .open = pstore_file_open,
184 .read = pstore_file_read,
185 .llseek = pstore_file_llseek,
186 .release = seq_release,
187};
188
189
190
191
192
193static int pstore_unlink(struct inode *dir, struct dentry *dentry)
194{
195 struct pstore_private *p = d_inode(dentry)->i_private;
196 int err;
197
198 err = pstore_check_syslog_permissions(p);
199 if (err)
200 return err;
201
202 if (p->psi->erase) {
203 mutex_lock(&p->psi->read_mutex);
204 p->psi->erase(p->type, p->id, p->count,
205 d_inode(dentry)->i_ctime, p->psi);
206 mutex_unlock(&p->psi->read_mutex);
207 } else {
208 return -EPERM;
209 }
210
211 return simple_unlink(dir, dentry);
212}
213
214static void pstore_evict_inode(struct inode *inode)
215{
216 struct pstore_private *p = inode->i_private;
217 unsigned long flags;
218
219 clear_inode(inode);
220 if (p) {
221 spin_lock_irqsave(&allpstore_lock, flags);
222 list_del(&p->list);
223 spin_unlock_irqrestore(&allpstore_lock, flags);
224 kfree(p);
225 }
226}
227
228static const struct inode_operations pstore_dir_inode_operations = {
229 .lookup = simple_lookup,
230 .unlink = pstore_unlink,
231};
232
233static struct inode *pstore_get_inode(struct super_block *sb)
234{
235 struct inode *inode = new_inode(sb);
236 if (inode) {
237 inode->i_ino = get_next_ino();
238 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
239 }
240 return inode;
241}
242
243enum {
244 Opt_kmsg_bytes, Opt_err
245};
246
247static const match_table_t tokens = {
248 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
249 {Opt_err, NULL}
250};
251
252static void parse_options(char *options)
253{
254 char *p;
255 substring_t args[MAX_OPT_ARGS];
256 int option;
257
258 if (!options)
259 return;
260
261 while ((p = strsep(&options, ",")) != NULL) {
262 int token;
263
264 if (!*p)
265 continue;
266
267 token = match_token(p, tokens, args);
268 switch (token) {
269 case Opt_kmsg_bytes:
270 if (!match_int(&args[0], &option))
271 pstore_set_kmsg_bytes(option);
272 break;
273 }
274 }
275}
276
277static int pstore_remount(struct super_block *sb, int *flags, char *data)
278{
279 sync_filesystem(sb);
280 parse_options(data);
281
282 return 0;
283}
284
285static const struct super_operations pstore_ops = {
286 .statfs = simple_statfs,
287 .drop_inode = generic_delete_inode,
288 .evict_inode = pstore_evict_inode,
289 .remount_fs = pstore_remount,
290 .show_options = generic_show_options,
291};
292
293static struct super_block *pstore_sb;
294
295bool pstore_is_mounted(void)
296{
297 return pstore_sb != NULL;
298}
299
300
301
302
303
304
305int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
306 char *data, bool compressed, size_t size,
307 struct timespec time, struct pstore_info *psi)
308{
309 struct dentry *root = pstore_sb->s_root;
310 struct dentry *dentry;
311 struct inode *inode;
312 int rc = 0;
313 char name[PSTORE_NAMELEN];
314 struct pstore_private *private, *pos;
315 unsigned long flags;
316
317 spin_lock_irqsave(&allpstore_lock, flags);
318 list_for_each_entry(pos, &allpstore, list) {
319 if (pos->type == type &&
320 pos->id == id &&
321 pos->psi == psi) {
322 rc = -EEXIST;
323 break;
324 }
325 }
326 spin_unlock_irqrestore(&allpstore_lock, flags);
327 if (rc)
328 return rc;
329
330 rc = -ENOMEM;
331 inode = pstore_get_inode(pstore_sb);
332 if (!inode)
333 goto fail;
334 inode->i_mode = S_IFREG | 0444;
335 inode->i_fop = &pstore_file_operations;
336 private = kmalloc(sizeof *private + size, GFP_KERNEL);
337 if (!private)
338 goto fail_alloc;
339 private->type = type;
340 private->id = id;
341 private->count = count;
342 private->psi = psi;
343
344 switch (type) {
345 case PSTORE_TYPE_DMESG:
346 scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
347 psname, id, compressed ? ".enc.z" : "");
348 break;
349 case PSTORE_TYPE_CONSOLE:
350 scnprintf(name, sizeof(name), "console-%s-%lld", psname, id);
351 break;
352 case PSTORE_TYPE_FTRACE:
353 scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id);
354 break;
355 case PSTORE_TYPE_MCE:
356 scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id);
357 break;
358 case PSTORE_TYPE_PPC_RTAS:
359 scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id);
360 break;
361 case PSTORE_TYPE_PPC_OF:
362 scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
363 psname, id);
364 break;
365 case PSTORE_TYPE_PPC_COMMON:
366 scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
367 psname, id);
368 break;
369 case PSTORE_TYPE_PMSG:
370 scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
371 break;
372 case PSTORE_TYPE_PPC_OPAL:
373 sprintf(name, "powerpc-opal-%s-%lld", psname, id);
374 break;
375 case PSTORE_TYPE_UNKNOWN:
376 scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
377 break;
378 default:
379 scnprintf(name, sizeof(name), "type%d-%s-%lld",
380 type, psname, id);
381 break;
382 }
383
384 inode_lock(d_inode(root));
385
386 dentry = d_alloc_name(root, name);
387 if (!dentry)
388 goto fail_lockedalloc;
389
390 memcpy(private->data, data, size);
391 inode->i_size = private->size = size;
392
393 inode->i_private = private;
394
395 if (time.tv_sec)
396 inode->i_mtime = inode->i_ctime = time;
397
398 d_add(dentry, inode);
399
400 spin_lock_irqsave(&allpstore_lock, flags);
401 list_add(&private->list, &allpstore);
402 spin_unlock_irqrestore(&allpstore_lock, flags);
403
404 inode_unlock(d_inode(root));
405
406 return 0;
407
408fail_lockedalloc:
409 inode_unlock(d_inode(root));
410 kfree(private);
411fail_alloc:
412 iput(inode);
413
414fail:
415 return rc;
416}
417
418static int pstore_fill_super(struct super_block *sb, void *data, int silent)
419{
420 struct inode *inode;
421
422 save_mount_options(sb, data);
423
424 pstore_sb = sb;
425
426 sb->s_maxbytes = MAX_LFS_FILESIZE;
427 sb->s_blocksize = PAGE_SIZE;
428 sb->s_blocksize_bits = PAGE_SHIFT;
429 sb->s_magic = PSTOREFS_MAGIC;
430 sb->s_op = &pstore_ops;
431 sb->s_time_gran = 1;
432
433 parse_options(data);
434
435 inode = pstore_get_inode(sb);
436 if (inode) {
437 inode->i_mode = S_IFDIR | 0755;
438 inode->i_op = &pstore_dir_inode_operations;
439 inode->i_fop = &simple_dir_operations;
440 inc_nlink(inode);
441 }
442 sb->s_root = d_make_root(inode);
443 if (!sb->s_root)
444 return -ENOMEM;
445
446 pstore_get_records(0);
447
448 return 0;
449}
450
451static struct dentry *pstore_mount(struct file_system_type *fs_type,
452 int flags, const char *dev_name, void *data)
453{
454 return mount_single(fs_type, flags, data, pstore_fill_super);
455}
456
457static void pstore_kill_sb(struct super_block *sb)
458{
459 kill_litter_super(sb);
460 pstore_sb = NULL;
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
470static int __init init_pstore_fs(void)
471{
472 int err;
473
474
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}
486module_init(init_pstore_fs)
487
488static void __exit exit_pstore_fs(void)
489{
490 unregister_filesystem(&pstore_fs_type);
491 sysfs_remove_mount_point(fs_kobj, "pstore");
492}
493module_exit(exit_pstore_fs)
494
495MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
496MODULE_LICENSE("GPL");
497
