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1/*
2 * Persistent Storage - platform driver interface parts.
3 *
4 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/atomic.h>
21#include <linux/types.h>
22#include <linux/errno.h>
23#include <linux/init.h>
24#include <linux/kmsg_dump.h>
25#include <linux/module.h>
26#include <linux/pstore.h>
27#include <linux/string.h>
28#include <linux/slab.h>
29#include <linux/uaccess.h>
30
31#include "internal.h"
32
33/*
34 * pstore_lock just protects "psinfo" during
35 * calls to pstore_register()
36 */
37static DEFINE_SPINLOCK(pstore_lock);
38static struct pstore_info *psinfo;
39
40static char *backend;
41
42/* How much of the console log to snapshot */
43static unsigned long kmsg_bytes = 10240;
44
45void pstore_set_kmsg_bytes(int bytes)
46{
47 kmsg_bytes = bytes;
48}
49
50/* Tag each group of saved records with a sequence number */
51static int oopscount;
52
53static char *reason_str[] = {
54 "Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
55};
56
57/*
58 * callback from kmsg_dump. (s2,l2) has the most recently
59 * written bytes, older bytes are in (s1,l1). Save as much
60 * as we can from the end of the buffer.
61 */
62static void pstore_dump(struct kmsg_dumper *dumper,
63 enum kmsg_dump_reason reason,
64 const char *s1, unsigned long l1,
65 const char *s2, unsigned long l2)
66{
67 unsigned long s1_start, s2_start;
68 unsigned long l1_cpy, l2_cpy;
69 unsigned long size, total = 0;
70 char *dst, *why;
71 u64 id;
72 int hsize;
73 unsigned int part = 1;
74
75 if (reason < ARRAY_SIZE(reason_str))
76 why = reason_str[reason];
77 else
78 why = "Unknown";
79
80 mutex_lock(&psinfo->buf_mutex);
81 oopscount++;
82 while (total < kmsg_bytes) {
83 dst = psinfo->buf;
84 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
85 size = psinfo->bufsize - hsize;
86 dst += hsize;
87
88 l2_cpy = min(l2, size);
89 l1_cpy = min(l1, size - l2_cpy);
90
91 if (l1_cpy + l2_cpy == 0)
92 break;
93
94 s2_start = l2 - l2_cpy;
95 s1_start = l1 - l1_cpy;
96
97 memcpy(dst, s1 + s1_start, l1_cpy);
98 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
99
100 id = psinfo->write(PSTORE_TYPE_DMESG, part,
101 hsize + l1_cpy + l2_cpy, psinfo);
102 if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
103 pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
104 psinfo->buf, hsize + l1_cpy + l2_cpy,
105 CURRENT_TIME, psinfo);
106 l1 -= l1_cpy;
107 l2 -= l2_cpy;
108 total += l1_cpy + l2_cpy;
109 part++;
110 }
111 mutex_unlock(&psinfo->buf_mutex);
112}
113
114static struct kmsg_dumper pstore_dumper = {
115 .dump = pstore_dump,
116};
117
118/*
119 * platform specific persistent storage driver registers with
120 * us here. If pstore is already mounted, call the platform
121 * read function right away to populate the file system. If not
122 * then the pstore mount code will call us later to fill out
123 * the file system.
124 *
125 * Register with kmsg_dump to save last part of console log on panic.
126 */
127int pstore_register(struct pstore_info *psi)
128{
129 struct module *owner = psi->owner;
130
131 spin_lock(&pstore_lock);
132 if (psinfo) {
133 spin_unlock(&pstore_lock);
134 return -EBUSY;
135 }
136
137 if (backend && strcmp(backend, psi->name)) {
138 spin_unlock(&pstore_lock);
139 return -EINVAL;
140 }
141
142 psinfo = psi;
143 spin_unlock(&pstore_lock);
144
145 if (owner && !try_module_get(owner)) {
146 psinfo = NULL;
147 return -EINVAL;
148 }
149
150 if (pstore_is_mounted())
151 pstore_get_records();
152
153 kmsg_dump_register(&pstore_dumper);
154
155 return 0;
156}
157EXPORT_SYMBOL_GPL(pstore_register);
158
159/*
160 * Read all the records from the persistent store. Create and
161 * file files in our filesystem.
162 */
163void pstore_get_records(void)
164{
165 struct pstore_info *psi = psinfo;
166 ssize_t size;
167 u64 id;
168 enum pstore_type_id type;
169 struct timespec time;
170 int failed = 0, rc;
171
172 if (!psi)
173 return;
174
175 mutex_lock(&psinfo->buf_mutex);
176 rc = psi->open(psi);
177 if (rc)
178 goto out;
179
180 while ((size = psi->read(&id, &type, &time, psi)) > 0) {
181 if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
182 time, psi))
183 failed++;
184 }
185 psi->close(psi);
186out:
187 mutex_unlock(&psinfo->buf_mutex);
188
189 if (failed)
190 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
191 failed, psi->name);
192}
193
194/*
195 * Call platform driver to write a record to the
196 * persistent store.
197 */
198int pstore_write(enum pstore_type_id type, char *buf, size_t size)
199{
200 u64 id;
201
202 if (!psinfo)
203 return -ENODEV;
204
205 if (size > psinfo->bufsize)
206 return -EFBIG;
207
208 mutex_lock(&psinfo->buf_mutex);
209 memcpy(psinfo->buf, buf, size);
210 id = psinfo->write(type, 0, size, psinfo);
211 if (pstore_is_mounted())
212 pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
213 size, CURRENT_TIME, psinfo);
214 mutex_unlock(&psinfo->buf_mutex);
215
216 return 0;
217}
218EXPORT_SYMBOL_GPL(pstore_write);
219
220module_param(backend, charp, 0444);
221MODULE_PARM_DESC(backend, "Pstore backend to use");
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#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
32#include <linux/zlib.h>
33#endif
34#ifdef CONFIG_PSTORE_LZO_COMPRESS
35#include <linux/lzo.h>
36#endif
37#ifdef CONFIG_PSTORE_LZ4_COMPRESS
38#include <linux/lz4.h>
39#endif
40#include <linux/string.h>
41#include <linux/timer.h>
42#include <linux/slab.h>
43#include <linux/uaccess.h>
44#include <linux/hardirq.h>
45#include <linux/jiffies.h>
46#include <linux/workqueue.h>
47
48#include "internal.h"
49
50/*
51 * We defer making "oops" entries appear in pstore - see
52 * whether the system is actually still running well enough
53 * to let someone see the entry
54 */
55static int pstore_update_ms = -1;
56module_param_named(update_ms, pstore_update_ms, int, 0600);
57MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
58 "(default is -1, which means runtime updates are disabled; "
59 "enabling this option is not safe, it may lead to further "
60 "corruption on Oopses)");
61
62static int pstore_new_entry;
63
64static void pstore_timefunc(unsigned long);
65static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
66
67static void pstore_dowork(struct work_struct *);
68static DECLARE_WORK(pstore_work, pstore_dowork);
69
70/*
71 * pstore_lock just protects "psinfo" during
72 * calls to pstore_register()
73 */
74static DEFINE_SPINLOCK(pstore_lock);
75struct pstore_info *psinfo;
76
77static char *backend;
78
79/* Compression parameters */
80#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
81#define COMPR_LEVEL 6
82#define WINDOW_BITS 12
83#define MEM_LEVEL 4
84static struct z_stream_s stream;
85#else
86static unsigned char *workspace;
87#endif
88
89struct pstore_zbackend {
90 int (*compress)(const void *in, void *out, size_t inlen, size_t outlen);
91 int (*decompress)(void *in, void *out, size_t inlen, size_t outlen);
92 void (*allocate)(void);
93 void (*free)(void);
94
95 const char *name;
96};
97
98static char *big_oops_buf;
99static size_t big_oops_buf_sz;
100
101/* How much of the console log to snapshot */
102static unsigned long kmsg_bytes = 10240;
103
104void pstore_set_kmsg_bytes(int bytes)
105{
106 kmsg_bytes = bytes;
107}
108
109/* Tag each group of saved records with a sequence number */
110static int oopscount;
111
112static const char *get_reason_str(enum kmsg_dump_reason reason)
113{
114 switch (reason) {
115 case KMSG_DUMP_PANIC:
116 return "Panic";
117 case KMSG_DUMP_OOPS:
118 return "Oops";
119 case KMSG_DUMP_EMERG:
120 return "Emergency";
121 case KMSG_DUMP_RESTART:
122 return "Restart";
123 case KMSG_DUMP_HALT:
124 return "Halt";
125 case KMSG_DUMP_POWEROFF:
126 return "Poweroff";
127 default:
128 return "Unknown";
129 }
130}
131
132bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
133{
134 /*
135 * In case of NMI path, pstore shouldn't be blocked
136 * regardless of reason.
137 */
138 if (in_nmi())
139 return true;
140
141 switch (reason) {
142 /* In panic case, other cpus are stopped by smp_send_stop(). */
143 case KMSG_DUMP_PANIC:
144 /* Emergency restart shouldn't be blocked by spin lock. */
145 case KMSG_DUMP_EMERG:
146 return true;
147 default:
148 return false;
149 }
150}
151EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
152
153#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
154/* Derived from logfs_compress() */
155static int compress_zlib(const void *in, void *out, size_t inlen, size_t outlen)
156{
157 int err, ret;
158
159 ret = -EIO;
160 err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
161 MEM_LEVEL, Z_DEFAULT_STRATEGY);
162 if (err != Z_OK)
163 goto error;
164
165 stream.next_in = in;
166 stream.avail_in = inlen;
167 stream.total_in = 0;
168 stream.next_out = out;
169 stream.avail_out = outlen;
170 stream.total_out = 0;
171
172 err = zlib_deflate(&stream, Z_FINISH);
173 if (err != Z_STREAM_END)
174 goto error;
175
176 err = zlib_deflateEnd(&stream);
177 if (err != Z_OK)
178 goto error;
179
180 if (stream.total_out >= stream.total_in)
181 goto error;
182
183 ret = stream.total_out;
184error:
185 return ret;
186}
187
188/* Derived from logfs_uncompress */
189static int decompress_zlib(void *in, void *out, size_t inlen, size_t outlen)
190{
191 int err, ret;
192
193 ret = -EIO;
194 err = zlib_inflateInit2(&stream, WINDOW_BITS);
195 if (err != Z_OK)
196 goto error;
197
198 stream.next_in = in;
199 stream.avail_in = inlen;
200 stream.total_in = 0;
201 stream.next_out = out;
202 stream.avail_out = outlen;
203 stream.total_out = 0;
204
205 err = zlib_inflate(&stream, Z_FINISH);
206 if (err != Z_STREAM_END)
207 goto error;
208
209 err = zlib_inflateEnd(&stream);
210 if (err != Z_OK)
211 goto error;
212
213 ret = stream.total_out;
214error:
215 return ret;
216}
217
218static void allocate_zlib(void)
219{
220 size_t size;
221 size_t cmpr;
222
223 switch (psinfo->bufsize) {
224 /* buffer range for efivars */
225 case 1000 ... 2000:
226 cmpr = 56;
227 break;
228 case 2001 ... 3000:
229 cmpr = 54;
230 break;
231 case 3001 ... 3999:
232 cmpr = 52;
233 break;
234 /* buffer range for nvram, erst */
235 case 4000 ... 10000:
236 cmpr = 45;
237 break;
238 default:
239 cmpr = 60;
240 break;
241 }
242
243 big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
244 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
245 if (big_oops_buf) {
246 size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
247 zlib_inflate_workspacesize());
248 stream.workspace = kmalloc(size, GFP_KERNEL);
249 if (!stream.workspace) {
250 pr_err("No memory for compression workspace; skipping compression\n");
251 kfree(big_oops_buf);
252 big_oops_buf = NULL;
253 }
254 } else {
255 pr_err("No memory for uncompressed data; skipping compression\n");
256 stream.workspace = NULL;
257 }
258
259}
260
261static void free_zlib(void)
262{
263 kfree(stream.workspace);
264 stream.workspace = NULL;
265 kfree(big_oops_buf);
266 big_oops_buf = NULL;
267 big_oops_buf_sz = 0;
268}
269
270static struct pstore_zbackend backend_zlib = {
271 .compress = compress_zlib,
272 .decompress = decompress_zlib,
273 .allocate = allocate_zlib,
274 .free = free_zlib,
275 .name = "zlib",
276};
277#endif
278
279#ifdef CONFIG_PSTORE_LZO_COMPRESS
280static int compress_lzo(const void *in, void *out, size_t inlen, size_t outlen)
281{
282 int ret;
283
284 ret = lzo1x_1_compress(in, inlen, out, &outlen, workspace);
285 if (ret != LZO_E_OK) {
286 pr_err("lzo_compress error, ret = %d!\n", ret);
287 return -EIO;
288 }
289
290 return outlen;
291}
292
293static int decompress_lzo(void *in, void *out, size_t inlen, size_t outlen)
294{
295 int ret;
296
297 ret = lzo1x_decompress_safe(in, inlen, out, &outlen);
298 if (ret != LZO_E_OK) {
299 pr_err("lzo_decompress error, ret = %d!\n", ret);
300 return -EIO;
301 }
302
303 return outlen;
304}
305
306static void allocate_lzo(void)
307{
308 big_oops_buf_sz = lzo1x_worst_compress(psinfo->bufsize);
309 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
310 if (big_oops_buf) {
311 workspace = kmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
312 if (!workspace) {
313 pr_err("No memory for compression workspace; skipping compression\n");
314 kfree(big_oops_buf);
315 big_oops_buf = NULL;
316 }
317 } else {
318 pr_err("No memory for uncompressed data; skipping compression\n");
319 workspace = NULL;
320 }
321}
322
323static void free_lzo(void)
324{
325 kfree(workspace);
326 kfree(big_oops_buf);
327 big_oops_buf = NULL;
328 big_oops_buf_sz = 0;
329}
330
331static struct pstore_zbackend backend_lzo = {
332 .compress = compress_lzo,
333 .decompress = decompress_lzo,
334 .allocate = allocate_lzo,
335 .free = free_lzo,
336 .name = "lzo",
337};
338#endif
339
340#ifdef CONFIG_PSTORE_LZ4_COMPRESS
341static int compress_lz4(const void *in, void *out, size_t inlen, size_t outlen)
342{
343 int ret;
344
345 ret = lz4_compress(in, inlen, out, &outlen, workspace);
346 if (ret) {
347 pr_err("lz4_compress error, ret = %d!\n", ret);
348 return -EIO;
349 }
350
351 return outlen;
352}
353
354static int decompress_lz4(void *in, void *out, size_t inlen, size_t outlen)
355{
356 int ret;
357
358 ret = lz4_decompress_unknownoutputsize(in, inlen, out, &outlen);
359 if (ret) {
360 pr_err("lz4_decompress error, ret = %d!\n", ret);
361 return -EIO;
362 }
363
364 return outlen;
365}
366
367static void allocate_lz4(void)
368{
369 big_oops_buf_sz = lz4_compressbound(psinfo->bufsize);
370 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
371 if (big_oops_buf) {
372 workspace = kmalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
373 if (!workspace) {
374 pr_err("No memory for compression workspace; skipping compression\n");
375 kfree(big_oops_buf);
376 big_oops_buf = NULL;
377 }
378 } else {
379 pr_err("No memory for uncompressed data; skipping compression\n");
380 workspace = NULL;
381 }
382}
383
384static void free_lz4(void)
385{
386 kfree(workspace);
387 kfree(big_oops_buf);
388 big_oops_buf = NULL;
389 big_oops_buf_sz = 0;
390}
391
392static struct pstore_zbackend backend_lz4 = {
393 .compress = compress_lz4,
394 .decompress = decompress_lz4,
395 .allocate = allocate_lz4,
396 .free = free_lz4,
397 .name = "lz4",
398};
399#endif
400
401static struct pstore_zbackend *zbackend =
402#if defined(CONFIG_PSTORE_ZLIB_COMPRESS)
403 &backend_zlib;
404#elif defined(CONFIG_PSTORE_LZO_COMPRESS)
405 &backend_lzo;
406#elif defined(CONFIG_PSTORE_LZ4_COMPRESS)
407 &backend_lz4;
408#else
409 NULL;
410#endif
411
412static int pstore_compress(const void *in, void *out,
413 size_t inlen, size_t outlen)
414{
415 if (zbackend)
416 return zbackend->compress(in, out, inlen, outlen);
417 else
418 return -EIO;
419}
420
421static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
422{
423 if (zbackend)
424 return zbackend->decompress(in, out, inlen, outlen);
425 else
426 return -EIO;
427}
428
429static void allocate_buf_for_compression(void)
430{
431 if (zbackend) {
432 pr_info("using %s compression\n", zbackend->name);
433 zbackend->allocate();
434 } else {
435 pr_err("allocate compression buffer error!\n");
436 }
437}
438
439static void free_buf_for_compression(void)
440{
441 if (zbackend)
442 zbackend->free();
443 else
444 pr_err("free compression buffer error!\n");
445}
446
447/*
448 * Called when compression fails, since the printk buffer
449 * would be fetched for compression calling it again when
450 * compression fails would have moved the iterator of
451 * printk buffer which results in fetching old contents.
452 * Copy the recent messages from big_oops_buf to psinfo->buf
453 */
454static size_t copy_kmsg_to_buffer(int hsize, size_t len)
455{
456 size_t total_len;
457 size_t diff;
458
459 total_len = hsize + len;
460
461 if (total_len > psinfo->bufsize) {
462 diff = total_len - psinfo->bufsize + hsize;
463 memcpy(psinfo->buf, big_oops_buf, hsize);
464 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
465 psinfo->bufsize - hsize);
466 total_len = psinfo->bufsize;
467 } else
468 memcpy(psinfo->buf, big_oops_buf, total_len);
469
470 return total_len;
471}
472
473/*
474 * callback from kmsg_dump. (s2,l2) has the most recently
475 * written bytes, older bytes are in (s1,l1). Save as much
476 * as we can from the end of the buffer.
477 */
478static void pstore_dump(struct kmsg_dumper *dumper,
479 enum kmsg_dump_reason reason)
480{
481 unsigned long total = 0;
482 const char *why;
483 u64 id;
484 unsigned int part = 1;
485 unsigned long flags = 0;
486 int is_locked;
487 int ret;
488
489 why = get_reason_str(reason);
490
491 if (pstore_cannot_block_path(reason)) {
492 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
493 if (!is_locked) {
494 pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
495 , in_nmi() ? "NMI" : why);
496 return;
497 }
498 } else {
499 spin_lock_irqsave(&psinfo->buf_lock, flags);
500 is_locked = 1;
501 }
502 oopscount++;
503 while (total < kmsg_bytes) {
504 char *dst;
505 unsigned long size;
506 int hsize;
507 int zipped_len = -1;
508 size_t len;
509 bool compressed = false;
510 size_t total_len;
511
512 if (big_oops_buf && is_locked) {
513 dst = big_oops_buf;
514 size = big_oops_buf_sz;
515 } else {
516 dst = psinfo->buf;
517 size = psinfo->bufsize;
518 }
519
520 hsize = sprintf(dst, "%s#%d Part%u\n", why, oopscount, part);
521 size -= hsize;
522
523 if (!kmsg_dump_get_buffer(dumper, true, dst + hsize,
524 size, &len))
525 break;
526
527 if (big_oops_buf && is_locked) {
528 zipped_len = pstore_compress(dst, psinfo->buf,
529 hsize + len, psinfo->bufsize);
530
531 if (zipped_len > 0) {
532 compressed = true;
533 total_len = zipped_len;
534 } else {
535 total_len = copy_kmsg_to_buffer(hsize, len);
536 }
537 } else {
538 total_len = hsize + len;
539 }
540
541 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
542 oopscount, compressed, total_len, psinfo);
543 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
544 pstore_new_entry = 1;
545
546 total += total_len;
547 part++;
548 }
549 if (is_locked)
550 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
551}
552
553static struct kmsg_dumper pstore_dumper = {
554 .dump = pstore_dump,
555};
556
557/*
558 * Register with kmsg_dump to save last part of console log on panic.
559 */
560static void pstore_register_kmsg(void)
561{
562 kmsg_dump_register(&pstore_dumper);
563}
564
565static void pstore_unregister_kmsg(void)
566{
567 kmsg_dump_unregister(&pstore_dumper);
568}
569
570#ifdef CONFIG_PSTORE_CONSOLE
571static void pstore_console_write(struct console *con, const char *s, unsigned c)
572{
573 const char *e = s + c;
574
575 while (s < e) {
576 unsigned long flags;
577 u64 id;
578
579 if (c > psinfo->bufsize)
580 c = psinfo->bufsize;
581
582 if (oops_in_progress) {
583 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
584 break;
585 } else {
586 spin_lock_irqsave(&psinfo->buf_lock, flags);
587 }
588 psinfo->write_buf(PSTORE_TYPE_CONSOLE, 0, &id, 0,
589 s, 0, c, psinfo);
590 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
591 s += c;
592 c = e - s;
593 }
594}
595
596static struct console pstore_console = {
597 .name = "pstore",
598 .write = pstore_console_write,
599 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
600 .index = -1,
601};
602
603static void pstore_register_console(void)
604{
605 register_console(&pstore_console);
606}
607
608static void pstore_unregister_console(void)
609{
610 unregister_console(&pstore_console);
611}
612#else
613static void pstore_register_console(void) {}
614static void pstore_unregister_console(void) {}
615#endif
616
617static int pstore_write_compat(enum pstore_type_id type,
618 enum kmsg_dump_reason reason,
619 u64 *id, unsigned int part, int count,
620 bool compressed, size_t size,
621 struct pstore_info *psi)
622{
623 return psi->write_buf(type, reason, id, part, psinfo->buf, compressed,
624 size, psi);
625}
626
627static int pstore_write_buf_user_compat(enum pstore_type_id type,
628 enum kmsg_dump_reason reason,
629 u64 *id, unsigned int part,
630 const char __user *buf,
631 bool compressed, size_t size,
632 struct pstore_info *psi)
633{
634 unsigned long flags = 0;
635 size_t i, bufsize = size;
636 long ret = 0;
637
638 if (unlikely(!access_ok(VERIFY_READ, buf, size)))
639 return -EFAULT;
640 if (bufsize > psinfo->bufsize)
641 bufsize = psinfo->bufsize;
642 spin_lock_irqsave(&psinfo->buf_lock, flags);
643 for (i = 0; i < size; ) {
644 size_t c = min(size - i, bufsize);
645
646 ret = __copy_from_user(psinfo->buf, buf + i, c);
647 if (unlikely(ret != 0)) {
648 ret = -EFAULT;
649 break;
650 }
651 ret = psi->write_buf(type, reason, id, part, psinfo->buf,
652 compressed, c, psi);
653 if (unlikely(ret < 0))
654 break;
655 i += c;
656 }
657 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
658 return unlikely(ret < 0) ? ret : size;
659}
660
661/*
662 * platform specific persistent storage driver registers with
663 * us here. If pstore is already mounted, call the platform
664 * read function right away to populate the file system. If not
665 * then the pstore mount code will call us later to fill out
666 * the file system.
667 */
668int pstore_register(struct pstore_info *psi)
669{
670 struct module *owner = psi->owner;
671
672 if (backend && strcmp(backend, psi->name))
673 return -EPERM;
674
675 spin_lock(&pstore_lock);
676 if (psinfo) {
677 spin_unlock(&pstore_lock);
678 return -EBUSY;
679 }
680
681 if (!psi->write)
682 psi->write = pstore_write_compat;
683 if (!psi->write_buf_user)
684 psi->write_buf_user = pstore_write_buf_user_compat;
685 psinfo = psi;
686 mutex_init(&psinfo->read_mutex);
687 spin_unlock(&pstore_lock);
688
689 if (owner && !try_module_get(owner)) {
690 psinfo = NULL;
691 return -EINVAL;
692 }
693
694 allocate_buf_for_compression();
695
696 if (pstore_is_mounted())
697 pstore_get_records(0);
698
699 if (psi->flags & PSTORE_FLAGS_DMESG)
700 pstore_register_kmsg();
701 if (psi->flags & PSTORE_FLAGS_CONSOLE)
702 pstore_register_console();
703 if (psi->flags & PSTORE_FLAGS_FTRACE)
704 pstore_register_ftrace();
705 if (psi->flags & PSTORE_FLAGS_PMSG)
706 pstore_register_pmsg();
707
708 if (pstore_update_ms >= 0) {
709 pstore_timer.expires = jiffies +
710 msecs_to_jiffies(pstore_update_ms);
711 add_timer(&pstore_timer);
712 }
713
714 /*
715 * Update the module parameter backend, so it is visible
716 * through /sys/module/pstore/parameters/backend
717 */
718 backend = psi->name;
719
720 module_put(owner);
721
722 pr_info("Registered %s as persistent store backend\n", psi->name);
723
724 return 0;
725}
726EXPORT_SYMBOL_GPL(pstore_register);
727
728void pstore_unregister(struct pstore_info *psi)
729{
730 if (psi->flags & PSTORE_FLAGS_PMSG)
731 pstore_unregister_pmsg();
732 if (psi->flags & PSTORE_FLAGS_FTRACE)
733 pstore_unregister_ftrace();
734 if (psi->flags & PSTORE_FLAGS_CONSOLE)
735 pstore_unregister_console();
736 if (psi->flags & PSTORE_FLAGS_DMESG)
737 pstore_unregister_kmsg();
738
739 free_buf_for_compression();
740
741 psinfo = NULL;
742 backend = NULL;
743}
744EXPORT_SYMBOL_GPL(pstore_unregister);
745
746/*
747 * Read all the records from the persistent store. Create
748 * files in our filesystem. Don't warn about -EEXIST errors
749 * when we are re-scanning the backing store looking to add new
750 * error records.
751 */
752void pstore_get_records(int quiet)
753{
754 struct pstore_info *psi = psinfo;
755 char *buf = NULL;
756 ssize_t size;
757 u64 id;
758 int count;
759 enum pstore_type_id type;
760 struct timespec time;
761 int failed = 0, rc;
762 bool compressed;
763 int unzipped_len = -1;
764 ssize_t ecc_notice_size = 0;
765
766 if (!psi)
767 return;
768
769 mutex_lock(&psi->read_mutex);
770 if (psi->open && psi->open(psi))
771 goto out;
772
773 while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
774 &ecc_notice_size, psi)) > 0) {
775 if (compressed && (type == PSTORE_TYPE_DMESG)) {
776 if (big_oops_buf)
777 unzipped_len = pstore_decompress(buf,
778 big_oops_buf, size,
779 big_oops_buf_sz);
780
781 if (unzipped_len > 0) {
782 if (ecc_notice_size)
783 memcpy(big_oops_buf + unzipped_len,
784 buf + size, ecc_notice_size);
785 kfree(buf);
786 buf = big_oops_buf;
787 size = unzipped_len;
788 compressed = false;
789 } else {
790 pr_err("decompression failed;returned %d\n",
791 unzipped_len);
792 compressed = true;
793 }
794 }
795 rc = pstore_mkfile(type, psi->name, id, count, buf,
796 compressed, size + ecc_notice_size,
797 time, psi);
798 if (unzipped_len < 0) {
799 /* Free buffer other than big oops */
800 kfree(buf);
801 buf = NULL;
802 } else
803 unzipped_len = -1;
804 if (rc && (rc != -EEXIST || !quiet))
805 failed++;
806 }
807 if (psi->close)
808 psi->close(psi);
809out:
810 mutex_unlock(&psi->read_mutex);
811
812 if (failed)
813 pr_warn("failed to load %d record(s) from '%s'\n",
814 failed, psi->name);
815}
816
817static void pstore_dowork(struct work_struct *work)
818{
819 pstore_get_records(1);
820}
821
822static void pstore_timefunc(unsigned long dummy)
823{
824 if (pstore_new_entry) {
825 pstore_new_entry = 0;
826 schedule_work(&pstore_work);
827 }
828
829 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
830}
831
832module_param(backend, charp, 0444);
833MODULE_PARM_DESC(backend, "Pstore backend to use");