1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
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
44
45
46
47static int pstore_update_ms = -1;
48module_param_named(update_ms, pstore_update_ms, int, 0600);
49MODULE_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
54static int pstore_new_entry;
55
56static void pstore_timefunc(unsigned long);
57static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
58
59static void pstore_dowork(struct work_struct *);
60static DECLARE_WORK(pstore_work, pstore_dowork);
61
62
63
64
65
66static DEFINE_SPINLOCK(pstore_lock);
67struct pstore_info *psinfo;
68
69static char *backend;
70
71
72#define COMPR_LEVEL 6
73#define WINDOW_BITS 12
74#define MEM_LEVEL 4
75static struct z_stream_s stream;
76
77static char *big_oops_buf;
78static size_t big_oops_buf_sz;
79
80
81static unsigned long kmsg_bytes = 10240;
82
83void pstore_set_kmsg_bytes(int bytes)
84{
85 kmsg_bytes = bytes;
86}
87
88
89static int oopscount;
90
91static 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
111bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
112{
113
114
115
116
117 if (in_nmi())
118 return true;
119
120 switch (reason) {
121
122 case KMSG_DUMP_PANIC:
123
124 case KMSG_DUMP_EMERG:
125 return true;
126 default:
127 return false;
128 }
129}
130EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
131
132
133static 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;
163error:
164 return ret;
165}
166
167
168static 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;
193error:
194 return ret;
195}
196
197static void allocate_buf_for_compression(void)
198{
199 size_t size;
200 size_t cmpr;
201
202 switch (psinfo->bufsize) {
203
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
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
242
243
244
245
246
247static 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
268
269
270
271static 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%u\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%u\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
352static struct kmsg_dumper pstore_dumper = {
353 .dump = pstore_dump,
354};
355
356#ifdef CONFIG_PSTORE_CONSOLE
357static 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
382static 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
389static void pstore_register_console(void)
390{
391 register_console(&pstore_console);
392}
393#else
394static void pstore_register_console(void) {}
395#endif
396
397static 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
407
408
409
410
411
412
413
414
415
416int pstore_register(struct pstore_info *psi)
417{
418 struct module *owner = psi->owner;
419
420 if (backend && strcmp(backend, psi->name))
421 return -EPERM;
422
423 spin_lock(&pstore_lock);
424 if (psinfo) {
425 spin_unlock(&pstore_lock);
426 return -EBUSY;
427 }
428
429 if (!psi->write)
430 psi->write = pstore_write_compat;
431 psinfo = psi;
432 mutex_init(&psinfo->read_mutex);
433 spin_unlock(&pstore_lock);
434
435 if (owner && !try_module_get(owner)) {
436 psinfo = NULL;
437 return -EINVAL;
438 }
439
440 allocate_buf_for_compression();
441
442 if (pstore_is_mounted())
443 pstore_get_records(0);
444
445 kmsg_dump_register(&pstore_dumper);
446
447 if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
448 pstore_register_console();
449 pstore_register_ftrace();
450 pstore_register_pmsg();
451 }
452
453 if (pstore_update_ms >= 0) {
454 pstore_timer.expires = jiffies +
455 msecs_to_jiffies(pstore_update_ms);
456 add_timer(&pstore_timer);
457 }
458
459 pr_info("Registered %s as persistent store backend\n", psi->name);
460
461 return 0;
462}
463EXPORT_SYMBOL_GPL(pstore_register);
464
465
466
467
468
469
470
471void pstore_get_records(int quiet)
472{
473 struct pstore_info *psi = psinfo;
474 char *buf = NULL;
475 ssize_t size;
476 u64 id;
477 int count;
478 enum pstore_type_id type;
479 struct timespec time;
480 int failed = 0, rc;
481 bool compressed;
482 int unzipped_len = -1;
483
484 if (!psi)
485 return;
486
487 mutex_lock(&psi->read_mutex);
488 if (psi->open && psi->open(psi))
489 goto out;
490
491 while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
492 psi)) > 0) {
493 if (compressed && (type == PSTORE_TYPE_DMESG)) {
494 if (big_oops_buf)
495 unzipped_len = pstore_decompress(buf,
496 big_oops_buf, size,
497 big_oops_buf_sz);
498
499 if (unzipped_len > 0) {
500 kfree(buf);
501 buf = big_oops_buf;
502 size = unzipped_len;
503 compressed = false;
504 } else {
505 pr_err("decompression failed;returned %d\n",
506 unzipped_len);
507 compressed = true;
508 }
509 }
510 rc = pstore_mkfile(type, psi->name, id, count, buf,
511 compressed, (size_t)size, time, psi);
512 if (unzipped_len < 0) {
513
514 kfree(buf);
515 buf = NULL;
516 } else
517 unzipped_len = -1;
518 if (rc && (rc != -EEXIST || !quiet))
519 failed++;
520 }
521 if (psi->close)
522 psi->close(psi);
523out:
524 mutex_unlock(&psi->read_mutex);
525
526 if (failed)
527 pr_warn("failed to load %d record(s) from '%s'\n",
528 failed, psi->name);
529}
530
531static void pstore_dowork(struct work_struct *work)
532{
533 pstore_get_records(1);
534}
535
536static void pstore_timefunc(unsigned long dummy)
537{
538 if (pstore_new_entry) {
539 pstore_new_entry = 0;
540 schedule_work(&pstore_work);
541 }
542
543 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
544}
545
546module_param(backend, charp, 0444);
547MODULE_PARM_DESC(backend, "Pstore backend to use");
548