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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, "%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
117static 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
124static 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
136static 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
147static 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
171static 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
180static const struct file_operations pstore_file_operations = {
181 .owner = THIS_MODULE,
182 .open = pstore_file_open,
183 .read = pstore_file_read,
184 .llseek = pstore_file_llseek,
185 .release = seq_release,
186};
187
188
189
190
191
192static int pstore_unlink(struct inode *dir, struct dentry *dentry)
193{
194 struct pstore_private *p = d_inode(dentry)->i_private;
195 int err;
196
197 err = pstore_check_syslog_permissions(p);
198 if (err)
199 return err;
200
201 if (p->psi->erase)
202 p->psi->erase(p->type, p->id, p->count,
203 d_inode(dentry)->i_ctime, p->psi);
204 else
205 return -EPERM;
206
207 return simple_unlink(dir, dentry);
208}
209
210static void pstore_evict_inode(struct inode *inode)
211{
212 struct pstore_private *p = inode->i_private;
213 unsigned long flags;
214
215 clear_inode(inode);
216 if (p) {
217 spin_lock_irqsave(&allpstore_lock, flags);
218 list_del(&p->list);
219 spin_unlock_irqrestore(&allpstore_lock, flags);
220 kfree(p);
221 }
222}
223
224static const struct inode_operations pstore_dir_inode_operations = {
225 .lookup = simple_lookup,
226 .unlink = pstore_unlink,
227};
228
229static struct inode *pstore_get_inode(struct super_block *sb)
230{
231 struct inode *inode = new_inode(sb);
232 if (inode) {
233 inode->i_ino = get_next_ino();
234 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
235 }
236 return inode;
237}
238
239enum {
240 Opt_kmsg_bytes, Opt_err
241};
242
243static const match_table_t tokens = {
244 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
245 {Opt_err, NULL}
246};
247
248static void parse_options(char *options)
249{
250 char *p;
251 substring_t args[MAX_OPT_ARGS];
252 int option;
253
254 if (!options)
255 return;
256
257 while ((p = strsep(&options, ",")) != NULL) {
258 int token;
259
260 if (!*p)
261 continue;
262
263 token = match_token(p, tokens, args);
264 switch (token) {
265 case Opt_kmsg_bytes:
266 if (!match_int(&args[0], &option))
267 pstore_set_kmsg_bytes(option);
268 break;
269 }
270 }
271}
272
273static int pstore_remount(struct super_block *sb, int *flags, char *data)
274{
275 sync_filesystem(sb);
276 parse_options(data);
277
278 return 0;
279}
280
281static const struct super_operations pstore_ops = {
282 .statfs = simple_statfs,
283 .drop_inode = generic_delete_inode,
284 .evict_inode = pstore_evict_inode,
285 .remount_fs = pstore_remount,
286 .show_options = generic_show_options,
287};
288
289static struct super_block *pstore_sb;
290
291bool pstore_is_mounted(void)
292{
293 return pstore_sb != NULL;
294}
295
296
297
298
299
300
301int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
302 char *data, bool compressed, size_t size,
303 struct timespec time, struct pstore_info *psi)
304{
305 struct dentry *root = pstore_sb->s_root;
306 struct dentry *dentry;
307 struct inode *inode;
308 int rc = 0;
309 char name[PSTORE_NAMELEN];
310 struct pstore_private *private, *pos;
311 unsigned long flags;
312
313 spin_lock_irqsave(&allpstore_lock, flags);
314 list_for_each_entry(pos, &allpstore, list) {
315 if (pos->type == type &&
316 pos->id == id &&
317 pos->psi == psi) {
318 rc = -EEXIST;
319 break;
320 }
321 }
322 spin_unlock_irqrestore(&allpstore_lock, flags);
323 if (rc)
324 return rc;
325
326 rc = -ENOMEM;
327 inode = pstore_get_inode(pstore_sb);
328 if (!inode)
329 goto fail;
330 inode->i_mode = S_IFREG | 0444;
331 inode->i_fop = &pstore_file_operations;
332 private = kmalloc(sizeof *private + size, GFP_KERNEL);
333 if (!private)
334 goto fail_alloc;
335 private->type = type;
336 private->id = id;
337 private->count = count;
338 private->psi = psi;
339
340 switch (type) {
341 case PSTORE_TYPE_DMESG:
342 scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
343 psname, id, compressed ? ".enc.z" : "");
344 break;
345 case PSTORE_TYPE_CONSOLE:
346 scnprintf(name, sizeof(name), "console-%s-%lld", psname, id);
347 break;
348 case PSTORE_TYPE_FTRACE:
349 scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id);
350 break;
351 case PSTORE_TYPE_MCE:
352 scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id);
353 break;
354 case PSTORE_TYPE_PPC_RTAS:
355 scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id);
356 break;
357 case PSTORE_TYPE_PPC_OF:
358 scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
359 psname, id);
360 break;
361 case PSTORE_TYPE_PPC_COMMON:
362 scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
363 psname, id);
364 break;
365 case PSTORE_TYPE_PMSG:
366 scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
367 break;
368 case PSTORE_TYPE_PPC_OPAL:
369 sprintf(name, "powerpc-opal-%s-%lld", psname, id);
370 break;
371 case PSTORE_TYPE_UNKNOWN:
372 scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
373 break;
374 default:
375 scnprintf(name, sizeof(name), "type%d-%s-%lld",
376 type, psname, id);
377 break;
378 }
379
380 inode_lock(d_inode(root));
381
382 dentry = d_alloc_name(root, name);
383 if (!dentry)
384 goto fail_lockedalloc;
385
386 memcpy(private->data, data, size);
387 inode->i_size = private->size = size;
388
389 inode->i_private = private;
390
391 if (time.tv_sec)
392 inode->i_mtime = inode->i_ctime = time;
393
394 d_add(dentry, inode);
395
396 spin_lock_irqsave(&allpstore_lock, flags);
397 list_add(&private->list, &allpstore);
398 spin_unlock_irqrestore(&allpstore_lock, flags);
399
400 inode_unlock(d_inode(root));
401
402 return 0;
403
404fail_lockedalloc:
405 inode_unlock(d_inode(root));
406 kfree(private);
407fail_alloc:
408 iput(inode);
409
410fail:
411 return rc;
412}
413
414static int pstore_fill_super(struct super_block *sb, void *data, int silent)
415{
416 struct inode *inode;
417
418 save_mount_options(sb, data);
419
420 pstore_sb = sb;
421
422 sb->s_maxbytes = MAX_LFS_FILESIZE;
423 sb->s_blocksize = PAGE_SIZE;
424 sb->s_blocksize_bits = PAGE_SHIFT;
425 sb->s_magic = PSTOREFS_MAGIC;
426 sb->s_op = &pstore_ops;
427 sb->s_time_gran = 1;
428
429 parse_options(data);
430
431 inode = pstore_get_inode(sb);
432 if (inode) {
433 inode->i_mode = S_IFDIR | 0755;
434 inode->i_op = &pstore_dir_inode_operations;
435 inode->i_fop = &simple_dir_operations;
436 inc_nlink(inode);
437 }
438 sb->s_root = d_make_root(inode);
439 if (!sb->s_root)
440 return -ENOMEM;
441
442 pstore_get_records(0);
443
444 return 0;
445}
446
447static struct dentry *pstore_mount(struct file_system_type *fs_type,
448 int flags, const char *dev_name, void *data)
449{
450 return mount_single(fs_type, flags, data, pstore_fill_super);
451}
452
453static void pstore_kill_sb(struct super_block *sb)
454{
455 kill_litter_super(sb);
456 pstore_sb = NULL;
457}
458
459static struct file_system_type pstore_fs_type = {
460 .owner = THIS_MODULE,
461 .name = "pstore",
462 .mount = pstore_mount,
463 .kill_sb = pstore_kill_sb,
464};
465
466static int __init init_pstore_fs(void)
467{
468 int err;
469
470
471 err = sysfs_create_mount_point(fs_kobj, "pstore");
472 if (err)
473 goto out;
474
475 err = register_filesystem(&pstore_fs_type);
476 if (err < 0)
477 sysfs_remove_mount_point(fs_kobj, "pstore");
478
479out:
480 return err;
481}
482module_init(init_pstore_fs)
483
484static void __exit exit_pstore_fs(void)
485{
486 unregister_filesystem(&pstore_fs_type);
487 sysfs_remove_mount_point(fs_kobj, "pstore");
488}
489module_exit(exit_pstore_fs)
490
491MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
492MODULE_LICENSE("GPL");
493
