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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#include <linux/atomic.h>
22#include <linux/types.h>
23#include <linux/errno.h>
24#include <linux/init.h>
25#include <linux/kmsg_dump.h>
26#include <linux/console.h>
27#include <linux/module.h>
28#include <linux/pstore.h>
29#include <linux/zlib.h>
30#include <linux/string.h>
31#include <linux/timer.h>
32#include <linux/slab.h>
33#include <linux/uaccess.h>
34#include <linux/hardirq.h>
35#include <linux/jiffies.h>
36#include <linux/workqueue.h>
37
38#include "internal.h"
39
40/*
41 * We defer making "oops" entries appear in pstore - see
42 * whether the system is actually still running well enough
43 * to let someone see the entry
44 */
45static int pstore_update_ms = -1;
46module_param_named(update_ms, pstore_update_ms, int, 0600);
47MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
48 "(default is -1, which means runtime updates are disabled; "
49 "enabling this option is not safe, it may lead to further "
50 "corruption on Oopses)");
51
52static int pstore_new_entry;
53
54static void pstore_timefunc(unsigned long);
55static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
56
57static void pstore_dowork(struct work_struct *);
58static DECLARE_WORK(pstore_work, pstore_dowork);
59
60/*
61 * pstore_lock just protects "psinfo" during
62 * calls to pstore_register()
63 */
64static DEFINE_SPINLOCK(pstore_lock);
65struct pstore_info *psinfo;
66
67static char *backend;
68
69/* Compression parameters */
70#define COMPR_LEVEL 6
71#define WINDOW_BITS 12
72#define MEM_LEVEL 4
73static struct z_stream_s stream;
74
75static char *big_oops_buf;
76static size_t big_oops_buf_sz;
77
78/* How much of the console log to snapshot */
79static unsigned long kmsg_bytes = 10240;
80
81void pstore_set_kmsg_bytes(int bytes)
82{
83 kmsg_bytes = bytes;
84}
85
86/* Tag each group of saved records with a sequence number */
87static int oopscount;
88
89static const char *get_reason_str(enum kmsg_dump_reason reason)
90{
91 switch (reason) {
92 case KMSG_DUMP_PANIC:
93 return "Panic";
94 case KMSG_DUMP_OOPS:
95 return "Oops";
96 case KMSG_DUMP_EMERG:
97 return "Emergency";
98 case KMSG_DUMP_RESTART:
99 return "Restart";
100 case KMSG_DUMP_HALT:
101 return "Halt";
102 case KMSG_DUMP_POWEROFF:
103 return "Poweroff";
104 default:
105 return "Unknown";
106 }
107}
108
109bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
110{
111 /*
112 * In case of NMI path, pstore shouldn't be blocked
113 * regardless of reason.
114 */
115 if (in_nmi())
116 return true;
117
118 switch (reason) {
119 /* In panic case, other cpus are stopped by smp_send_stop(). */
120 case KMSG_DUMP_PANIC:
121 /* Emergency restart shouldn't be blocked by spin lock. */
122 case KMSG_DUMP_EMERG:
123 return true;
124 default:
125 return false;
126 }
127}
128EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
129
130/* Derived from logfs_compress() */
131static int pstore_compress(const void *in, void *out, size_t inlen,
132 size_t outlen)
133{
134 int err, ret;
135
136 ret = -EIO;
137 err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
138 MEM_LEVEL, Z_DEFAULT_STRATEGY);
139 if (err != Z_OK)
140 goto error;
141
142 stream.next_in = in;
143 stream.avail_in = inlen;
144 stream.total_in = 0;
145 stream.next_out = out;
146 stream.avail_out = outlen;
147 stream.total_out = 0;
148
149 err = zlib_deflate(&stream, Z_FINISH);
150 if (err != Z_STREAM_END)
151 goto error;
152
153 err = zlib_deflateEnd(&stream);
154 if (err != Z_OK)
155 goto error;
156
157 if (stream.total_out >= stream.total_in)
158 goto error;
159
160 ret = stream.total_out;
161error:
162 return ret;
163}
164
165/* Derived from logfs_uncompress */
166static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
167{
168 int err, ret;
169
170 ret = -EIO;
171 err = zlib_inflateInit2(&stream, WINDOW_BITS);
172 if (err != Z_OK)
173 goto error;
174
175 stream.next_in = in;
176 stream.avail_in = inlen;
177 stream.total_in = 0;
178 stream.next_out = out;
179 stream.avail_out = outlen;
180 stream.total_out = 0;
181
182 err = zlib_inflate(&stream, Z_FINISH);
183 if (err != Z_STREAM_END)
184 goto error;
185
186 err = zlib_inflateEnd(&stream);
187 if (err != Z_OK)
188 goto error;
189
190 ret = stream.total_out;
191error:
192 return ret;
193}
194
195static void allocate_buf_for_compression(void)
196{
197 size_t size;
198 size_t cmpr;
199
200 switch (psinfo->bufsize) {
201 /* buffer range for efivars */
202 case 1000 ... 2000:
203 cmpr = 56;
204 break;
205 case 2001 ... 3000:
206 cmpr = 54;
207 break;
208 case 3001 ... 3999:
209 cmpr = 52;
210 break;
211 /* buffer range for nvram, erst */
212 case 4000 ... 10000:
213 cmpr = 45;
214 break;
215 default:
216 cmpr = 60;
217 break;
218 }
219
220 big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
221 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
222 if (big_oops_buf) {
223 size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
224 zlib_inflate_workspacesize());
225 stream.workspace = kmalloc(size, GFP_KERNEL);
226 if (!stream.workspace) {
227 pr_err("pstore: No memory for compression workspace; "
228 "skipping compression\n");
229 kfree(big_oops_buf);
230 big_oops_buf = NULL;
231 }
232 } else {
233 pr_err("No memory for uncompressed data; "
234 "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 */
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 * 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 */
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%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
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 * platform specific persistent storage driver registers with
409 * us here. If pstore is already mounted, call the platform
410 * read function right away to populate the file system. If not
411 * then the pstore mount code will call us later to fill out
412 * the file system.
413 *
414 * Register with kmsg_dump to save last part of console log on panic.
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 }
451
452 if (pstore_update_ms >= 0) {
453 pstore_timer.expires = jiffies +
454 msecs_to_jiffies(pstore_update_ms);
455 add_timer(&pstore_timer);
456 }
457
458 pr_info("pstore: Registered %s as persistent store backend\n",
459 psi->name);
460
461 return 0;
462}
463EXPORT_SYMBOL_GPL(pstore_register);
464
465/*
466 * Read all the records from the persistent store. Create
467 * files in our filesystem. Don't warn about -EEXIST errors
468 * when we are re-scanning the backing store looking to add new
469 * error records.
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("pstore: decompression failed;"
506 "returned %d\n", 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 /* Free buffer other than big oops */
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 printk(KERN_WARNING "pstore: 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");
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 */
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 * pstore_lock just protects "psinfo" during
64 * calls to pstore_register()
65 */
66static DEFINE_SPINLOCK(pstore_lock);
67struct pstore_info *psinfo;
68
69static char *backend;
70
71/* Compression parameters */
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/* How much of the console log to snapshot */
81static unsigned long kmsg_bytes = 10240;
82
83void pstore_set_kmsg_bytes(int bytes)
84{
85 kmsg_bytes = bytes;
86}
87
88/* Tag each group of saved records with a sequence number */
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 * 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}
130EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
131
132/* Derived from logfs_compress() */
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/* Derived from logfs_uncompress */
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 /* 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
240static void free_buf_for_compression(void)
241{
242 kfree(stream.workspace);
243 stream.workspace = NULL;
244 kfree(big_oops_buf);
245 big_oops_buf = NULL;
246}
247
248/*
249 * Called when compression fails, since the printk buffer
250 * would be fetched for compression calling it again when
251 * compression fails would have moved the iterator of
252 * printk buffer which results in fetching old contents.
253 * Copy the recent messages from big_oops_buf to psinfo->buf
254 */
255static size_t copy_kmsg_to_buffer(int hsize, size_t len)
256{
257 size_t total_len;
258 size_t diff;
259
260 total_len = hsize + len;
261
262 if (total_len > psinfo->bufsize) {
263 diff = total_len - psinfo->bufsize + hsize;
264 memcpy(psinfo->buf, big_oops_buf, hsize);
265 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
266 psinfo->bufsize - hsize);
267 total_len = psinfo->bufsize;
268 } else
269 memcpy(psinfo->buf, big_oops_buf, total_len);
270
271 return total_len;
272}
273
274/*
275 * callback from kmsg_dump. (s2,l2) has the most recently
276 * written bytes, older bytes are in (s1,l1). Save as much
277 * as we can from the end of the buffer.
278 */
279static void pstore_dump(struct kmsg_dumper *dumper,
280 enum kmsg_dump_reason reason)
281{
282 unsigned long total = 0;
283 const char *why;
284 u64 id;
285 unsigned int part = 1;
286 unsigned long flags = 0;
287 int is_locked = 0;
288 int ret;
289
290 why = get_reason_str(reason);
291
292 if (pstore_cannot_block_path(reason)) {
293 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
294 if (!is_locked) {
295 pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
296 , in_nmi() ? "NMI" : why);
297 }
298 } else
299 spin_lock_irqsave(&psinfo->buf_lock, flags);
300 oopscount++;
301 while (total < kmsg_bytes) {
302 char *dst;
303 unsigned long size;
304 int hsize;
305 int zipped_len = -1;
306 size_t len;
307 bool compressed;
308 size_t total_len;
309
310 if (big_oops_buf && is_locked) {
311 dst = big_oops_buf;
312 hsize = sprintf(dst, "%s#%d Part%u\n", why,
313 oopscount, part);
314 size = big_oops_buf_sz - hsize;
315
316 if (!kmsg_dump_get_buffer(dumper, true, dst + hsize,
317 size, &len))
318 break;
319
320 zipped_len = pstore_compress(dst, psinfo->buf,
321 hsize + len, psinfo->bufsize);
322
323 if (zipped_len > 0) {
324 compressed = true;
325 total_len = zipped_len;
326 } else {
327 compressed = false;
328 total_len = copy_kmsg_to_buffer(hsize, len);
329 }
330 } else {
331 dst = psinfo->buf;
332 hsize = sprintf(dst, "%s#%d Part%u\n", why, oopscount,
333 part);
334 size = psinfo->bufsize - hsize;
335 dst += hsize;
336
337 if (!kmsg_dump_get_buffer(dumper, true, dst,
338 size, &len))
339 break;
340
341 compressed = false;
342 total_len = hsize + len;
343 }
344
345 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
346 oopscount, compressed, total_len, psinfo);
347 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
348 pstore_new_entry = 1;
349
350 total += total_len;
351 part++;
352 }
353 if (pstore_cannot_block_path(reason)) {
354 if (is_locked)
355 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
356 } else
357 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
358}
359
360static struct kmsg_dumper pstore_dumper = {
361 .dump = pstore_dump,
362};
363
364/*
365 * Register with kmsg_dump to save last part of console log on panic.
366 */
367static void pstore_register_kmsg(void)
368{
369 kmsg_dump_register(&pstore_dumper);
370}
371
372static void pstore_unregister_kmsg(void)
373{
374 kmsg_dump_unregister(&pstore_dumper);
375}
376
377#ifdef CONFIG_PSTORE_CONSOLE
378static void pstore_console_write(struct console *con, const char *s, unsigned c)
379{
380 const char *e = s + c;
381
382 while (s < e) {
383 unsigned long flags;
384 u64 id;
385
386 if (c > psinfo->bufsize)
387 c = psinfo->bufsize;
388
389 if (oops_in_progress) {
390 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
391 break;
392 } else {
393 spin_lock_irqsave(&psinfo->buf_lock, flags);
394 }
395 memcpy(psinfo->buf, s, c);
396 psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
397 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
398 s += c;
399 c = e - s;
400 }
401}
402
403static struct console pstore_console = {
404 .name = "pstore",
405 .write = pstore_console_write,
406 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
407 .index = -1,
408};
409
410static void pstore_register_console(void)
411{
412 register_console(&pstore_console);
413}
414
415static void pstore_unregister_console(void)
416{
417 unregister_console(&pstore_console);
418}
419#else
420static void pstore_register_console(void) {}
421static void pstore_unregister_console(void) {}
422#endif
423
424static int pstore_write_compat(enum pstore_type_id type,
425 enum kmsg_dump_reason reason,
426 u64 *id, unsigned int part, int count,
427 bool compressed, size_t size,
428 struct pstore_info *psi)
429{
430 return psi->write_buf(type, reason, id, part, psinfo->buf, compressed,
431 size, psi);
432}
433
434/*
435 * platform specific persistent storage driver registers with
436 * us here. If pstore is already mounted, call the platform
437 * read function right away to populate the file system. If not
438 * then the pstore mount code will call us later to fill out
439 * the file system.
440 */
441int pstore_register(struct pstore_info *psi)
442{
443 struct module *owner = psi->owner;
444
445 if (backend && strcmp(backend, psi->name))
446 return -EPERM;
447
448 spin_lock(&pstore_lock);
449 if (psinfo) {
450 spin_unlock(&pstore_lock);
451 return -EBUSY;
452 }
453
454 if (!psi->write)
455 psi->write = pstore_write_compat;
456 psinfo = psi;
457 mutex_init(&psinfo->read_mutex);
458 spin_unlock(&pstore_lock);
459
460 if (owner && !try_module_get(owner)) {
461 psinfo = NULL;
462 return -EINVAL;
463 }
464
465 allocate_buf_for_compression();
466
467 if (pstore_is_mounted())
468 pstore_get_records(0);
469
470 pstore_register_kmsg();
471
472 if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
473 pstore_register_console();
474 pstore_register_ftrace();
475 pstore_register_pmsg();
476 }
477
478 if (pstore_update_ms >= 0) {
479 pstore_timer.expires = jiffies +
480 msecs_to_jiffies(pstore_update_ms);
481 add_timer(&pstore_timer);
482 }
483
484 /*
485 * Update the module parameter backend, so it is visible
486 * through /sys/module/pstore/parameters/backend
487 */
488 backend = psi->name;
489
490 module_put(owner);
491
492 pr_info("Registered %s as persistent store backend\n", psi->name);
493
494 return 0;
495}
496EXPORT_SYMBOL_GPL(pstore_register);
497
498void pstore_unregister(struct pstore_info *psi)
499{
500 pstore_unregister_pmsg();
501 pstore_unregister_ftrace();
502 pstore_unregister_console();
503 pstore_unregister_kmsg();
504
505 free_buf_for_compression();
506
507 psinfo = NULL;
508 backend = NULL;
509}
510EXPORT_SYMBOL_GPL(pstore_unregister);
511
512/*
513 * Read all the records from the persistent store. Create
514 * files in our filesystem. Don't warn about -EEXIST errors
515 * when we are re-scanning the backing store looking to add new
516 * error records.
517 */
518void pstore_get_records(int quiet)
519{
520 struct pstore_info *psi = psinfo;
521 char *buf = NULL;
522 ssize_t size;
523 u64 id;
524 int count;
525 enum pstore_type_id type;
526 struct timespec time;
527 int failed = 0, rc;
528 bool compressed;
529 int unzipped_len = -1;
530
531 if (!psi)
532 return;
533
534 mutex_lock(&psi->read_mutex);
535 if (psi->open && psi->open(psi))
536 goto out;
537
538 while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
539 psi)) > 0) {
540 if (compressed && (type == PSTORE_TYPE_DMESG)) {
541 if (big_oops_buf)
542 unzipped_len = pstore_decompress(buf,
543 big_oops_buf, size,
544 big_oops_buf_sz);
545
546 if (unzipped_len > 0) {
547 kfree(buf);
548 buf = big_oops_buf;
549 size = unzipped_len;
550 compressed = false;
551 } else {
552 pr_err("decompression failed;returned %d\n",
553 unzipped_len);
554 compressed = true;
555 }
556 }
557 rc = pstore_mkfile(type, psi->name, id, count, buf,
558 compressed, (size_t)size, time, psi);
559 if (unzipped_len < 0) {
560 /* Free buffer other than big oops */
561 kfree(buf);
562 buf = NULL;
563 } else
564 unzipped_len = -1;
565 if (rc && (rc != -EEXIST || !quiet))
566 failed++;
567 }
568 if (psi->close)
569 psi->close(psi);
570out:
571 mutex_unlock(&psi->read_mutex);
572
573 if (failed)
574 pr_warn("failed to load %d record(s) from '%s'\n",
575 failed, psi->name);
576}
577
578static void pstore_dowork(struct work_struct *work)
579{
580 pstore_get_records(1);
581}
582
583static void pstore_timefunc(unsigned long dummy)
584{
585 if (pstore_new_entry) {
586 pstore_new_entry = 0;
587 schedule_work(&pstore_work);
588 }
589
590 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
591}
592
593module_param(backend, charp, 0444);
594MODULE_PARM_DESC(backend, "Pstore backend to use");