2 * Persistent Storage - platform driver interface parts.
4 * Copyright (C) 2007-2008 Google, Inc.
5 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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.
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.
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
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>
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
45 static int pstore_update_ms
= -1;
46 module_param_named(update_ms
, pstore_update_ms
, int, 0600);
47 MODULE_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)");
52 static int pstore_new_entry
;
54 static void pstore_timefunc(unsigned long);
55 static DEFINE_TIMER(pstore_timer
, pstore_timefunc
, 0, 0);
57 static void pstore_dowork(struct work_struct
*);
58 static DECLARE_WORK(pstore_work
, pstore_dowork
);
61 * pstore_lock just protects "psinfo" during
62 * calls to pstore_register()
64 static DEFINE_SPINLOCK(pstore_lock
);
65 struct pstore_info
*psinfo
;
69 /* Compression parameters */
71 #define WINDOW_BITS 12
73 static struct z_stream_s stream
;
75 static char *big_oops_buf
;
76 static size_t big_oops_buf_sz
;
78 /* How much of the console log to snapshot */
79 static unsigned long kmsg_bytes
= 10240;
81 void pstore_set_kmsg_bytes(int bytes
)
86 /* Tag each group of saved records with a sequence number */
89 static const char *get_reason_str(enum kmsg_dump_reason reason
)
98 case KMSG_DUMP_RESTART
:
102 case KMSG_DUMP_POWEROFF
:
109 bool pstore_cannot_block_path(enum kmsg_dump_reason reason
)
112 * In case of NMI path, pstore shouldn't be blocked
113 * regardless of 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
:
128 EXPORT_SYMBOL_GPL(pstore_cannot_block_path
);
130 /* Derived from logfs_compress() */
131 static int pstore_compress(const void *in
, void *out
, size_t inlen
,
137 err
= zlib_deflateInit2(&stream
, COMPR_LEVEL
, Z_DEFLATED
, WINDOW_BITS
,
138 MEM_LEVEL
, Z_DEFAULT_STRATEGY
);
143 stream
.avail_in
= inlen
;
145 stream
.next_out
= out
;
146 stream
.avail_out
= outlen
;
147 stream
.total_out
= 0;
149 err
= zlib_deflate(&stream
, Z_FINISH
);
150 if (err
!= Z_STREAM_END
)
153 err
= zlib_deflateEnd(&stream
);
157 if (stream
.total_out
>= stream
.total_in
)
160 ret
= stream
.total_out
;
165 /* Derived from logfs_uncompress */
166 static int pstore_decompress(void *in
, void *out
, size_t inlen
, size_t outlen
)
171 err
= zlib_inflateInit2(&stream
, WINDOW_BITS
);
176 stream
.avail_in
= inlen
;
178 stream
.next_out
= out
;
179 stream
.avail_out
= outlen
;
180 stream
.total_out
= 0;
182 err
= zlib_inflate(&stream
, Z_FINISH
);
183 if (err
!= Z_STREAM_END
)
186 err
= zlib_inflateEnd(&stream
);
190 ret
= stream
.total_out
;
195 static void allocate_buf_for_compression(void)
200 switch (psinfo
->bufsize
) {
201 /* buffer range for efivars */
211 /* buffer range for nvram, erst */
220 big_oops_buf_sz
= (psinfo
->bufsize
* 100) / cmpr
;
221 big_oops_buf
= kmalloc(big_oops_buf_sz
, GFP_KERNEL
);
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");
233 pr_err("No memory for uncompressed data; "
234 "skipping compression\n");
235 stream
.workspace
= NULL
;
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
247 static size_t copy_kmsg_to_buffer(int hsize
, size_t len
)
252 total_len
= hsize
+ len
;
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
;
261 memcpy(psinfo
->buf
, big_oops_buf
, total_len
);
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.
271 static void pstore_dump(struct kmsg_dumper
*dumper
,
272 enum kmsg_dump_reason reason
)
274 unsigned long total
= 0;
277 unsigned int part
= 1;
278 unsigned long flags
= 0;
282 why
= get_reason_str(reason
);
284 if (pstore_cannot_block_path(reason
)) {
285 is_locked
= spin_trylock_irqsave(&psinfo
->buf_lock
, flags
);
287 pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
288 , in_nmi() ? "NMI" : why
);
291 spin_lock_irqsave(&psinfo
->buf_lock
, flags
);
293 while (total
< kmsg_bytes
) {
304 hsize
= sprintf(dst
, "%s#%d Part%d\n", why
,
306 size
= big_oops_buf_sz
- hsize
;
308 if (!kmsg_dump_get_buffer(dumper
, true, dst
+ hsize
,
312 zipped_len
= pstore_compress(dst
, psinfo
->buf
,
313 hsize
+ len
, psinfo
->bufsize
);
315 if (zipped_len
> 0) {
317 total_len
= zipped_len
;
319 pr_err("pstore: compression failed for Part %d"
320 " returned %d\n", part
, zipped_len
);
321 pr_err("pstore: Capture uncompressed"
322 " oops/panic report of Part %d\n", part
);
324 total_len
= copy_kmsg_to_buffer(hsize
, len
);
328 hsize
= sprintf(dst
, "%s#%d Part%d\n", why
, oopscount
,
330 size
= psinfo
->bufsize
- hsize
;
333 if (!kmsg_dump_get_buffer(dumper
, true, dst
,
338 total_len
= hsize
+ len
;
341 ret
= psinfo
->write(PSTORE_TYPE_DMESG
, reason
, &id
, part
,
342 oopscount
, compressed
, total_len
, psinfo
);
343 if (ret
== 0 && reason
== KMSG_DUMP_OOPS
&& pstore_is_mounted())
344 pstore_new_entry
= 1;
349 if (pstore_cannot_block_path(reason
)) {
351 spin_unlock_irqrestore(&psinfo
->buf_lock
, flags
);
353 spin_unlock_irqrestore(&psinfo
->buf_lock
, flags
);
356 static struct kmsg_dumper pstore_dumper
= {
360 #ifdef CONFIG_PSTORE_CONSOLE
361 static void pstore_console_write(struct console
*con
, const char *s
, unsigned c
)
363 const char *e
= s
+ c
;
369 if (c
> psinfo
->bufsize
)
372 if (oops_in_progress
) {
373 if (!spin_trylock_irqsave(&psinfo
->buf_lock
, flags
))
376 spin_lock_irqsave(&psinfo
->buf_lock
, flags
);
378 memcpy(psinfo
->buf
, s
, c
);
379 psinfo
->write(PSTORE_TYPE_CONSOLE
, 0, &id
, 0, 0, 0, c
, psinfo
);
380 spin_unlock_irqrestore(&psinfo
->buf_lock
, flags
);
386 static struct console pstore_console
= {
388 .write
= pstore_console_write
,
389 .flags
= CON_PRINTBUFFER
| CON_ENABLED
| CON_ANYTIME
,
393 static void pstore_register_console(void)
395 register_console(&pstore_console
);
398 static void pstore_register_console(void) {}
401 static int pstore_write_compat(enum pstore_type_id type
,
402 enum kmsg_dump_reason reason
,
403 u64
*id
, unsigned int part
, int count
,
404 bool compressed
, size_t size
,
405 struct pstore_info
*psi
)
407 return psi
->write_buf(type
, reason
, id
, part
, psinfo
->buf
, compressed
,
412 * platform specific persistent storage driver registers with
413 * us here. If pstore is already mounted, call the platform
414 * read function right away to populate the file system. If not
415 * then the pstore mount code will call us later to fill out
418 * Register with kmsg_dump to save last part of console log on panic.
420 int pstore_register(struct pstore_info
*psi
)
422 struct module
*owner
= psi
->owner
;
424 if (backend
&& strcmp(backend
, psi
->name
))
427 spin_lock(&pstore_lock
);
429 spin_unlock(&pstore_lock
);
434 psi
->write
= pstore_write_compat
;
436 mutex_init(&psinfo
->read_mutex
);
437 spin_unlock(&pstore_lock
);
439 if (owner
&& !try_module_get(owner
)) {
444 allocate_buf_for_compression();
446 if (pstore_is_mounted())
447 pstore_get_records(0);
449 kmsg_dump_register(&pstore_dumper
);
450 pstore_register_console();
451 pstore_register_ftrace();
453 if (pstore_update_ms
>= 0) {
454 pstore_timer
.expires
= jiffies
+
455 msecs_to_jiffies(pstore_update_ms
);
456 add_timer(&pstore_timer
);
459 pr_info("pstore: Registered %s as persistent store backend\n",
464 EXPORT_SYMBOL_GPL(pstore_register
);
467 * Read all the records from the persistent store. Create
468 * files in our filesystem. Don't warn about -EEXIST errors
469 * when we are re-scanning the backing store looking to add new
472 void pstore_get_records(int quiet
)
474 struct pstore_info
*psi
= psinfo
;
479 enum pstore_type_id type
;
480 struct timespec time
;
483 int unzipped_len
= -1;
488 mutex_lock(&psi
->read_mutex
);
489 if (psi
->open
&& psi
->open(psi
))
492 while ((size
= psi
->read(&id
, &type
, &count
, &time
, &buf
, &compressed
,
494 if (compressed
&& (type
== PSTORE_TYPE_DMESG
)) {
496 unzipped_len
= pstore_decompress(buf
,
500 if (unzipped_len
> 0) {
505 pr_err("pstore: decompression failed;"
506 "returned %d\n", unzipped_len
);
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 */
518 if (rc
&& (rc
!= -EEXIST
|| !quiet
))
524 mutex_unlock(&psi
->read_mutex
);
527 printk(KERN_WARNING
"pstore: failed to load %d record(s) from '%s'\n",
531 static void pstore_dowork(struct work_struct
*work
)
533 pstore_get_records(1);
536 static void pstore_timefunc(unsigned long dummy
)
538 if (pstore_new_entry
) {
539 pstore_new_entry
= 0;
540 schedule_work(&pstore_work
);
543 mod_timer(&pstore_timer
, jiffies
+ msecs_to_jiffies(pstore_update_ms
));
546 module_param(backend
, charp
, 0444);
547 MODULE_PARM_DESC(backend
, "Pstore backend to use");