1 /*
2 * Persistent Storage - platform driver interface parts.
3 *
4 * Copyright (C) 2007-2008 Google, Inc.
5 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21 #define pr_fmt(fmt) "pstore: " fmt
22
23 #include <linux/atomic.h>
24 #include <linux/types.h>
25 #include <linux/errno.h>
26 #include <linux/init.h>
27 #include <linux/kmsg_dump.h>
28 #include <linux/console.h>
29 #include <linux/module.h>
30 #include <linux/pstore.h>
31 #include <linux/zlib.h>
32 #include <linux/string.h>
33 #include <linux/timer.h>
34 #include <linux/slab.h>
35 #include <linux/uaccess.h>
36 #include <linux/hardirq.h>
37 #include <linux/jiffies.h>
38 #include <linux/workqueue.h>
39
40 #include "internal.h"
41
42 /*
43 * We defer making "oops" entries appear in pstore - see
44 * whether the system is actually still running well enough
45 * to let someone see the entry
46 */
47 static int pstore_update_ms = -1;
48 module_param_named(update_ms, pstore_update_ms, int, 0600);
49 MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
50 "(default is -1, which means runtime updates are disabled; "
51 "enabling this option is not safe, it may lead to further "
52 "corruption on Oopses)");
53
54 static int pstore_new_entry;
55
56 static void pstore_timefunc(unsigned long);
57 static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
58
59 static void pstore_dowork(struct work_struct *);
60 static DECLARE_WORK(pstore_work, pstore_dowork);
61
62 /*
63 * pstore_lock just protects "psinfo" during
64 * calls to pstore_register()
65 */
66 static DEFINE_SPINLOCK(pstore_lock);
67 struct pstore_info *psinfo;
68
69 static char *backend;
70
71 /* Compression parameters */
72 #define COMPR_LEVEL 6
73 #define WINDOW_BITS 12
74 #define MEM_LEVEL 4
75 static struct z_stream_s stream;
76
77 static char *big_oops_buf;
78 static size_t big_oops_buf_sz;
79
80 /* How much of the console log to snapshot */
81 static unsigned long kmsg_bytes = 10240;
82
pstore_set_kmsg_bytes(int bytes)83 void pstore_set_kmsg_bytes(int bytes)
84 {
85 kmsg_bytes = bytes;
86 }
87
88 /* Tag each group of saved records with a sequence number */
89 static int oopscount;
90
get_reason_str(enum kmsg_dump_reason reason)91 static const char *get_reason_str(enum kmsg_dump_reason reason)
92 {
93 switch (reason) {
94 case KMSG_DUMP_PANIC:
95 return "Panic";
96 case KMSG_DUMP_OOPS:
97 return "Oops";
98 case KMSG_DUMP_EMERG:
99 return "Emergency";
100 case KMSG_DUMP_RESTART:
101 return "Restart";
102 case KMSG_DUMP_HALT:
103 return "Halt";
104 case KMSG_DUMP_POWEROFF:
105 return "Poweroff";
106 default:
107 return "Unknown";
108 }
109 }
110
pstore_cannot_block_path(enum kmsg_dump_reason reason)111 bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
112 {
113 /*
114 * In case of NMI path, pstore shouldn't be blocked
115 * regardless of reason.
116 */
117 if (in_nmi())
118 return true;
119
120 switch (reason) {
121 /* In panic case, other cpus are stopped by smp_send_stop(). */
122 case KMSG_DUMP_PANIC:
123 /* Emergency restart shouldn't be blocked by spin lock. */
124 case KMSG_DUMP_EMERG:
125 return true;
126 default:
127 return false;
128 }
129 }
130 EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
131
132 /* Derived from logfs_compress() */
pstore_compress(const void * in,void * out,size_t inlen,size_t outlen)133 static int pstore_compress(const void *in, void *out, size_t inlen,
134 size_t outlen)
135 {
136 int err, ret;
137
138 ret = -EIO;
139 err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
140 MEM_LEVEL, Z_DEFAULT_STRATEGY);
141 if (err != Z_OK)
142 goto error;
143
144 stream.next_in = in;
145 stream.avail_in = inlen;
146 stream.total_in = 0;
147 stream.next_out = out;
148 stream.avail_out = outlen;
149 stream.total_out = 0;
150
151 err = zlib_deflate(&stream, Z_FINISH);
152 if (err != Z_STREAM_END)
153 goto error;
154
155 err = zlib_deflateEnd(&stream);
156 if (err != Z_OK)
157 goto error;
158
159 if (stream.total_out >= stream.total_in)
160 goto error;
161
162 ret = stream.total_out;
163 error:
164 return ret;
165 }
166
167 /* Derived from logfs_uncompress */
pstore_decompress(void * in,void * out,size_t inlen,size_t outlen)168 static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
169 {
170 int err, ret;
171
172 ret = -EIO;
173 err = zlib_inflateInit2(&stream, WINDOW_BITS);
174 if (err != Z_OK)
175 goto error;
176
177 stream.next_in = in;
178 stream.avail_in = inlen;
179 stream.total_in = 0;
180 stream.next_out = out;
181 stream.avail_out = outlen;
182 stream.total_out = 0;
183
184 err = zlib_inflate(&stream, Z_FINISH);
185 if (err != Z_STREAM_END)
186 goto error;
187
188 err = zlib_inflateEnd(&stream);
189 if (err != Z_OK)
190 goto error;
191
192 ret = stream.total_out;
193 error:
194 return ret;
195 }
196
allocate_buf_for_compression(void)197 static void allocate_buf_for_compression(void)
198 {
199 size_t size;
200 size_t cmpr;
201
202 switch (psinfo->bufsize) {
203 /* buffer range for efivars */
204 case 1000 ... 2000:
205 cmpr = 56;
206 break;
207 case 2001 ... 3000:
208 cmpr = 54;
209 break;
210 case 3001 ... 3999:
211 cmpr = 52;
212 break;
213 /* buffer range for nvram, erst */
214 case 4000 ... 10000:
215 cmpr = 45;
216 break;
217 default:
218 cmpr = 60;
219 break;
220 }
221
222 big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
223 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
224 if (big_oops_buf) {
225 size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
226 zlib_inflate_workspacesize());
227 stream.workspace = kmalloc(size, GFP_KERNEL);
228 if (!stream.workspace) {
229 pr_err("No memory for compression workspace; skipping compression\n");
230 kfree(big_oops_buf);
231 big_oops_buf = NULL;
232 }
233 } else {
234 pr_err("No memory for uncompressed data; skipping compression\n");
235 stream.workspace = NULL;
236 }
237
238 }
239
240 /*
241 * Called when compression fails, since the printk buffer
242 * would be fetched for compression calling it again when
243 * compression fails would have moved the iterator of
244 * printk buffer which results in fetching old contents.
245 * Copy the recent messages from big_oops_buf to psinfo->buf
246 */
copy_kmsg_to_buffer(int hsize,size_t len)247 static size_t copy_kmsg_to_buffer(int hsize, size_t len)
248 {
249 size_t total_len;
250 size_t diff;
251
252 total_len = hsize + len;
253
254 if (total_len > psinfo->bufsize) {
255 diff = total_len - psinfo->bufsize + hsize;
256 memcpy(psinfo->buf, big_oops_buf, hsize);
257 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
258 psinfo->bufsize - hsize);
259 total_len = psinfo->bufsize;
260 } else
261 memcpy(psinfo->buf, big_oops_buf, total_len);
262
263 return total_len;
264 }
265
266 /*
267 * callback from kmsg_dump. (s2,l2) has the most recently
268 * written bytes, older bytes are in (s1,l1). Save as much
269 * as we can from the end of the buffer.
270 */
pstore_dump(struct kmsg_dumper * dumper,enum kmsg_dump_reason reason)271 static void pstore_dump(struct kmsg_dumper *dumper,
272 enum kmsg_dump_reason reason)
273 {
274 unsigned long total = 0;
275 const char *why;
276 u64 id;
277 unsigned int part = 1;
278 unsigned long flags = 0;
279 int is_locked = 0;
280 int ret;
281
282 why = get_reason_str(reason);
283
284 if (pstore_cannot_block_path(reason)) {
285 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
286 if (!is_locked) {
287 pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
288 , in_nmi() ? "NMI" : why);
289 }
290 } else
291 spin_lock_irqsave(&psinfo->buf_lock, flags);
292 oopscount++;
293 while (total < kmsg_bytes) {
294 char *dst;
295 unsigned long size;
296 int hsize;
297 int zipped_len = -1;
298 size_t len;
299 bool compressed;
300 size_t total_len;
301
302 if (big_oops_buf) {
303 dst = big_oops_buf;
304 hsize = sprintf(dst, "%s#%d Part%d\n", why,
305 oopscount, part);
306 size = big_oops_buf_sz - hsize;
307
308 if (!kmsg_dump_get_buffer(dumper, true, dst + hsize,
309 size, &len))
310 break;
311
312 zipped_len = pstore_compress(dst, psinfo->buf,
313 hsize + len, psinfo->bufsize);
314
315 if (zipped_len > 0) {
316 compressed = true;
317 total_len = zipped_len;
318 } else {
319 compressed = false;
320 total_len = copy_kmsg_to_buffer(hsize, len);
321 }
322 } else {
323 dst = psinfo->buf;
324 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount,
325 part);
326 size = psinfo->bufsize - hsize;
327 dst += hsize;
328
329 if (!kmsg_dump_get_buffer(dumper, true, dst,
330 size, &len))
331 break;
332
333 compressed = false;
334 total_len = hsize + len;
335 }
336
337 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
338 oopscount, compressed, total_len, psinfo);
339 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
340 pstore_new_entry = 1;
341
342 total += total_len;
343 part++;
344 }
345 if (pstore_cannot_block_path(reason)) {
346 if (is_locked)
347 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
348 } else
349 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
350 }
351
352 static struct kmsg_dumper pstore_dumper = {
353 .dump = pstore_dump,
354 };
355
356 #ifdef CONFIG_PSTORE_CONSOLE
pstore_console_write(struct console * con,const char * s,unsigned c)357 static void pstore_console_write(struct console *con, const char *s, unsigned c)
358 {
359 const char *e = s + c;
360
361 while (s < e) {
362 unsigned long flags;
363 u64 id;
364
365 if (c > psinfo->bufsize)
366 c = psinfo->bufsize;
367
368 if (oops_in_progress) {
369 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
370 break;
371 } else {
372 spin_lock_irqsave(&psinfo->buf_lock, flags);
373 }
374 memcpy(psinfo->buf, s, c);
375 psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
376 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
377 s += c;
378 c = e - s;
379 }
380 }
381
382 static struct console pstore_console = {
383 .name = "pstore",
384 .write = pstore_console_write,
385 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
386 .index = -1,
387 };
388
pstore_register_console(void)389 static void pstore_register_console(void)
390 {
391 register_console(&pstore_console);
392 }
393 #else
pstore_register_console(void)394 static void pstore_register_console(void) {}
395 #endif
396
pstore_write_compat(enum pstore_type_id type,enum kmsg_dump_reason reason,u64 * id,unsigned int part,int count,bool compressed,size_t size,struct pstore_info * psi)397 static int pstore_write_compat(enum pstore_type_id type,
398 enum kmsg_dump_reason reason,
399 u64 *id, unsigned int part, int count,
400 bool compressed, size_t size,
401 struct pstore_info *psi)
402 {
403 return psi->write_buf(type, reason, id, part, psinfo->buf, compressed,
404 size, psi);
405 }
406
pstore_write_buf_user_compat(enum pstore_type_id type,enum kmsg_dump_reason reason,u64 * id,unsigned int part,const char __user * buf,bool compressed,size_t size,struct pstore_info * psi)407 static int pstore_write_buf_user_compat(enum pstore_type_id type,
408 enum kmsg_dump_reason reason,
409 u64 *id, unsigned int part,
410 const char __user *buf,
411 bool compressed, size_t size,
412 struct pstore_info *psi)
413 {
414 unsigned long flags = 0;
415 size_t i, bufsize = size;
416 long ret = 0;
417
418 if (unlikely(!access_ok(VERIFY_READ, buf, size)))
419 return -EFAULT;
420 if (bufsize > psinfo->bufsize)
421 bufsize = psinfo->bufsize;
422 spin_lock_irqsave(&psinfo->buf_lock, flags);
423 for (i = 0; i < size; ) {
424 size_t c = min(size - i, bufsize);
425
426 ret = __copy_from_user(psinfo->buf, buf + i, c);
427 if (unlikely(ret != 0)) {
428 ret = -EFAULT;
429 break;
430 }
431 ret = psi->write_buf(type, reason, id, part, psinfo->buf,
432 compressed, c, psi);
433 if (unlikely(ret < 0))
434 break;
435 i += c;
436 }
437 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
438 return unlikely(ret < 0) ? ret : size;
439 }
440
441 /*
442 * platform specific persistent storage driver registers with
443 * us here. If pstore is already mounted, call the platform
444 * read function right away to populate the file system. If not
445 * then the pstore mount code will call us later to fill out
446 * the file system.
447 *
448 * Register with kmsg_dump to save last part of console log on panic.
449 */
pstore_register(struct pstore_info * psi)450 int pstore_register(struct pstore_info *psi)
451 {
452 struct module *owner = psi->owner;
453
454 if (backend && strcmp(backend, psi->name))
455 return -EPERM;
456
457 spin_lock(&pstore_lock);
458 if (psinfo) {
459 spin_unlock(&pstore_lock);
460 return -EBUSY;
461 }
462
463 if (!psi->write)
464 psi->write = pstore_write_compat;
465 if (!psi->write_buf_user)
466 psi->write_buf_user = pstore_write_buf_user_compat;
467 psinfo = psi;
468 mutex_init(&psinfo->read_mutex);
469 spin_unlock(&pstore_lock);
470
471 if (owner && !try_module_get(owner)) {
472 psinfo = NULL;
473 return -EINVAL;
474 }
475
476 allocate_buf_for_compression();
477
478 if (pstore_is_mounted())
479 pstore_get_records(0);
480
481 kmsg_dump_register(&pstore_dumper);
482
483 if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
484 pstore_register_console();
485 pstore_register_ftrace();
486 pstore_register_pmsg();
487 }
488
489 if (pstore_update_ms >= 0) {
490 pstore_timer.expires = jiffies +
491 msecs_to_jiffies(pstore_update_ms);
492 add_timer(&pstore_timer);
493 }
494
495 pr_info("Registered %s as persistent store backend\n", psi->name);
496
497 return 0;
498 }
499 EXPORT_SYMBOL_GPL(pstore_register);
500
501 /*
502 * Read all the records from the persistent store. Create
503 * files in our filesystem. Don't warn about -EEXIST errors
504 * when we are re-scanning the backing store looking to add new
505 * error records.
506 */
pstore_get_records(int quiet)507 void pstore_get_records(int quiet)
508 {
509 struct pstore_info *psi = psinfo;
510 char *buf = NULL;
511 ssize_t size;
512 u64 id;
513 int count;
514 enum pstore_type_id type;
515 struct timespec time;
516 int failed = 0, rc;
517 bool compressed;
518 int unzipped_len = -1;
519
520 if (!psi)
521 return;
522
523 mutex_lock(&psi->read_mutex);
524 if (psi->open && psi->open(psi))
525 goto out;
526
527 while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
528 psi)) > 0) {
529 if (compressed && (type == PSTORE_TYPE_DMESG)) {
530 if (big_oops_buf)
531 unzipped_len = pstore_decompress(buf,
532 big_oops_buf, size,
533 big_oops_buf_sz);
534
535 if (unzipped_len > 0) {
536 kfree(buf);
537 buf = big_oops_buf;
538 size = unzipped_len;
539 compressed = false;
540 } else {
541 pr_err("decompression failed;returned %d\n",
542 unzipped_len);
543 compressed = true;
544 }
545 }
546 rc = pstore_mkfile(type, psi->name, id, count, buf,
547 compressed, (size_t)size, time, psi);
548 if (unzipped_len < 0) {
549 /* Free buffer other than big oops */
550 kfree(buf);
551 buf = NULL;
552 } else
553 unzipped_len = -1;
554 if (rc && (rc != -EEXIST || !quiet))
555 failed++;
556 }
557 if (psi->close)
558 psi->close(psi);
559 out:
560 mutex_unlock(&psi->read_mutex);
561
562 if (failed)
563 pr_warn("failed to load %d record(s) from '%s'\n",
564 failed, psi->name);
565 }
566
pstore_dowork(struct work_struct * work)567 static void pstore_dowork(struct work_struct *work)
568 {
569 pstore_get_records(1);
570 }
571
pstore_timefunc(unsigned long dummy)572 static void pstore_timefunc(unsigned long dummy)
573 {
574 if (pstore_new_entry) {
575 pstore_new_entry = 0;
576 schedule_work(&pstore_work);
577 }
578
579 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
580 }
581
582 module_param(backend, charp, 0444);
583 MODULE_PARM_DESC(backend, "Pstore backend to use");
584