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