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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Persistent Storage - platform driver interface parts.
4 *
5 * Copyright (C) 2007-2008 Google, Inc.
6 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
7 */
8
9#define pr_fmt(fmt) "pstore: " fmt
10
11#include <linux/atomic.h>
12#include <linux/types.h>
13#include <linux/errno.h>
14#include <linux/init.h>
15#include <linux/kmsg_dump.h>
16#include <linux/console.h>
17#include <linux/module.h>
18#include <linux/pstore.h>
19#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
20#include <linux/lzo.h>
21#endif
22#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
23#include <linux/lz4.h>
24#endif
25#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
26#include <linux/zstd.h>
27#endif
28#include <linux/crypto.h>
29#include <linux/string.h>
30#include <linux/timer.h>
31#include <linux/slab.h>
32#include <linux/uaccess.h>
33#include <linux/jiffies.h>
34#include <linux/workqueue.h>
35
36#include "internal.h"
37
38/*
39 * We defer making "oops" entries appear in pstore - see
40 * whether the system is actually still running well enough
41 * to let someone see the entry
42 */
43static int pstore_update_ms = -1;
44module_param_named(update_ms, pstore_update_ms, int, 0600);
45MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
46 "(default is -1, which means runtime updates are disabled; "
47 "enabling this option is not safe, it may lead to further "
48 "corruption on Oopses)");
49
50/* Names should be in the same order as the enum pstore_type_id */
51static const char * const pstore_type_names[] = {
52 "dmesg",
53 "mce",
54 "console",
55 "ftrace",
56 "rtas",
57 "powerpc-ofw",
58 "powerpc-common",
59 "pmsg",
60 "powerpc-opal",
61};
62
63static int pstore_new_entry;
64
65static void pstore_timefunc(struct timer_list *);
66static DEFINE_TIMER(pstore_timer, pstore_timefunc);
67
68static void pstore_dowork(struct work_struct *);
69static DECLARE_WORK(pstore_work, pstore_dowork);
70
71/*
72 * pstore_lock just protects "psinfo" during
73 * calls to pstore_register()
74 */
75static DEFINE_SPINLOCK(pstore_lock);
76struct pstore_info *psinfo;
77
78static char *backend;
79static char *compress =
80#ifdef CONFIG_PSTORE_COMPRESS_DEFAULT
81 CONFIG_PSTORE_COMPRESS_DEFAULT;
82#else
83 NULL;
84#endif
85
86/* Compression parameters */
87static struct crypto_comp *tfm;
88
89struct pstore_zbackend {
90 int (*zbufsize)(size_t size);
91 const char *name;
92};
93
94static char *big_oops_buf;
95static size_t big_oops_buf_sz;
96
97/* How much of the console log to snapshot */
98unsigned long kmsg_bytes = PSTORE_DEFAULT_KMSG_BYTES;
99
100void pstore_set_kmsg_bytes(int bytes)
101{
102 kmsg_bytes = bytes;
103}
104
105/* Tag each group of saved records with a sequence number */
106static int oopscount;
107
108const char *pstore_type_to_name(enum pstore_type_id type)
109{
110 BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
111
112 if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
113 return "unknown";
114
115 return pstore_type_names[type];
116}
117EXPORT_SYMBOL_GPL(pstore_type_to_name);
118
119enum pstore_type_id pstore_name_to_type(const char *name)
120{
121 int i;
122
123 for (i = 0; i < PSTORE_TYPE_MAX; i++) {
124 if (!strcmp(pstore_type_names[i], name))
125 return i;
126 }
127
128 return PSTORE_TYPE_MAX;
129}
130EXPORT_SYMBOL_GPL(pstore_name_to_type);
131
132static const char *get_reason_str(enum kmsg_dump_reason reason)
133{
134 switch (reason) {
135 case KMSG_DUMP_PANIC:
136 return "Panic";
137 case KMSG_DUMP_OOPS:
138 return "Oops";
139 case KMSG_DUMP_EMERG:
140 return "Emergency";
141 case KMSG_DUMP_RESTART:
142 return "Restart";
143 case KMSG_DUMP_HALT:
144 return "Halt";
145 case KMSG_DUMP_POWEROFF:
146 return "Poweroff";
147 default:
148 return "Unknown";
149 }
150}
151
152/*
153 * Should pstore_dump() wait for a concurrent pstore_dump()? If
154 * not, the current pstore_dump() will report a failure to dump
155 * and return.
156 */
157static bool pstore_cannot_wait(enum kmsg_dump_reason reason)
158{
159 /* In NMI path, pstore shouldn't block regardless of reason. */
160 if (in_nmi())
161 return true;
162
163 switch (reason) {
164 /* In panic case, other cpus are stopped by smp_send_stop(). */
165 case KMSG_DUMP_PANIC:
166 /* Emergency restart shouldn't be blocked. */
167 case KMSG_DUMP_EMERG:
168 return true;
169 default:
170 return false;
171 }
172}
173
174#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
175static int zbufsize_deflate(size_t size)
176{
177 size_t cmpr;
178
179 switch (size) {
180 /* buffer range for efivars */
181 case 1000 ... 2000:
182 cmpr = 56;
183 break;
184 case 2001 ... 3000:
185 cmpr = 54;
186 break;
187 case 3001 ... 3999:
188 cmpr = 52;
189 break;
190 /* buffer range for nvram, erst */
191 case 4000 ... 10000:
192 cmpr = 45;
193 break;
194 default:
195 cmpr = 60;
196 break;
197 }
198
199 return (size * 100) / cmpr;
200}
201#endif
202
203#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
204static int zbufsize_lzo(size_t size)
205{
206 return lzo1x_worst_compress(size);
207}
208#endif
209
210#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
211static int zbufsize_lz4(size_t size)
212{
213 return LZ4_compressBound(size);
214}
215#endif
216
217#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
218static int zbufsize_842(size_t size)
219{
220 return size;
221}
222#endif
223
224#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
225static int zbufsize_zstd(size_t size)
226{
227 return ZSTD_compressBound(size);
228}
229#endif
230
231static const struct pstore_zbackend *zbackend __ro_after_init;
232
233static const struct pstore_zbackend zbackends[] = {
234#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
235 {
236 .zbufsize = zbufsize_deflate,
237 .name = "deflate",
238 },
239#endif
240#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
241 {
242 .zbufsize = zbufsize_lzo,
243 .name = "lzo",
244 },
245#endif
246#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS)
247 {
248 .zbufsize = zbufsize_lz4,
249 .name = "lz4",
250 },
251#endif
252#if IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
253 {
254 .zbufsize = zbufsize_lz4,
255 .name = "lz4hc",
256 },
257#endif
258#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
259 {
260 .zbufsize = zbufsize_842,
261 .name = "842",
262 },
263#endif
264#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
265 {
266 .zbufsize = zbufsize_zstd,
267 .name = "zstd",
268 },
269#endif
270 { }
271};
272
273static int pstore_compress(const void *in, void *out,
274 unsigned int inlen, unsigned int outlen)
275{
276 int ret;
277
278 ret = crypto_comp_compress(tfm, in, inlen, out, &outlen);
279 if (ret) {
280 pr_err("crypto_comp_compress failed, ret = %d!\n", ret);
281 return ret;
282 }
283
284 return outlen;
285}
286
287static void allocate_buf_for_compression(void)
288{
289 struct crypto_comp *ctx;
290 int size;
291 char *buf;
292
293 /* Skip if not built-in or compression backend not selected yet. */
294 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
295 return;
296
297 /* Skip if no pstore backend yet or compression init already done. */
298 if (!psinfo || tfm)
299 return;
300
301 if (!crypto_has_comp(zbackend->name, 0, 0)) {
302 pr_err("Unknown compression: %s\n", zbackend->name);
303 return;
304 }
305
306 size = zbackend->zbufsize(psinfo->bufsize);
307 if (size <= 0) {
308 pr_err("Invalid compression size for %s: %d\n",
309 zbackend->name, size);
310 return;
311 }
312
313 buf = kmalloc(size, GFP_KERNEL);
314 if (!buf) {
315 pr_err("Failed %d byte compression buffer allocation for: %s\n",
316 size, zbackend->name);
317 return;
318 }
319
320 ctx = crypto_alloc_comp(zbackend->name, 0, 0);
321 if (IS_ERR_OR_NULL(ctx)) {
322 kfree(buf);
323 pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
324 PTR_ERR(ctx));
325 return;
326 }
327
328 /* A non-NULL big_oops_buf indicates compression is available. */
329 tfm = ctx;
330 big_oops_buf_sz = size;
331 big_oops_buf = buf;
332
333 pr_info("Using crash dump compression: %s\n", zbackend->name);
334}
335
336static void free_buf_for_compression(void)
337{
338 if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) {
339 crypto_free_comp(tfm);
340 tfm = NULL;
341 }
342 kfree(big_oops_buf);
343 big_oops_buf = NULL;
344 big_oops_buf_sz = 0;
345}
346
347/*
348 * Called when compression fails, since the printk buffer
349 * would be fetched for compression calling it again when
350 * compression fails would have moved the iterator of
351 * printk buffer which results in fetching old contents.
352 * Copy the recent messages from big_oops_buf to psinfo->buf
353 */
354static size_t copy_kmsg_to_buffer(int hsize, size_t len)
355{
356 size_t total_len;
357 size_t diff;
358
359 total_len = hsize + len;
360
361 if (total_len > psinfo->bufsize) {
362 diff = total_len - psinfo->bufsize + hsize;
363 memcpy(psinfo->buf, big_oops_buf, hsize);
364 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
365 psinfo->bufsize - hsize);
366 total_len = psinfo->bufsize;
367 } else
368 memcpy(psinfo->buf, big_oops_buf, total_len);
369
370 return total_len;
371}
372
373void pstore_record_init(struct pstore_record *record,
374 struct pstore_info *psinfo)
375{
376 memset(record, 0, sizeof(*record));
377
378 record->psi = psinfo;
379
380 /* Report zeroed timestamp if called before timekeeping has resumed. */
381 record->time = ns_to_timespec64(ktime_get_real_fast_ns());
382}
383
384/*
385 * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
386 * end of the buffer.
387 */
388static void pstore_dump(struct kmsg_dumper *dumper,
389 enum kmsg_dump_reason reason)
390{
391 unsigned long total = 0;
392 const char *why;
393 unsigned int part = 1;
394 int ret;
395
396 why = get_reason_str(reason);
397
398 if (down_trylock(&psinfo->buf_lock)) {
399 /* Failed to acquire lock: give up if we cannot wait. */
400 if (pstore_cannot_wait(reason)) {
401 pr_err("dump skipped in %s path: may corrupt error record\n",
402 in_nmi() ? "NMI" : why);
403 return;
404 }
405 if (down_interruptible(&psinfo->buf_lock)) {
406 pr_err("could not grab semaphore?!\n");
407 return;
408 }
409 }
410
411 oopscount++;
412 while (total < kmsg_bytes) {
413 char *dst;
414 size_t dst_size;
415 int header_size;
416 int zipped_len = -1;
417 size_t dump_size;
418 struct pstore_record record;
419
420 pstore_record_init(&record, psinfo);
421 record.type = PSTORE_TYPE_DMESG;
422 record.count = oopscount;
423 record.reason = reason;
424 record.part = part;
425 record.buf = psinfo->buf;
426
427 if (big_oops_buf) {
428 dst = big_oops_buf;
429 dst_size = big_oops_buf_sz;
430 } else {
431 dst = psinfo->buf;
432 dst_size = psinfo->bufsize;
433 }
434
435 /* Write dump header. */
436 header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
437 oopscount, part);
438 dst_size -= header_size;
439
440 /* Write dump contents. */
441 if (!kmsg_dump_get_buffer(dumper, true, dst + header_size,
442 dst_size, &dump_size))
443 break;
444
445 if (big_oops_buf) {
446 zipped_len = pstore_compress(dst, psinfo->buf,
447 header_size + dump_size,
448 psinfo->bufsize);
449
450 if (zipped_len > 0) {
451 record.compressed = true;
452 record.size = zipped_len;
453 } else {
454 record.size = copy_kmsg_to_buffer(header_size,
455 dump_size);
456 }
457 } else {
458 record.size = header_size + dump_size;
459 }
460
461 ret = psinfo->write(&record);
462 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
463 pstore_new_entry = 1;
464
465 total += record.size;
466 part++;
467 }
468
469 up(&psinfo->buf_lock);
470}
471
472static struct kmsg_dumper pstore_dumper = {
473 .dump = pstore_dump,
474};
475
476/*
477 * Register with kmsg_dump to save last part of console log on panic.
478 */
479static void pstore_register_kmsg(void)
480{
481 kmsg_dump_register(&pstore_dumper);
482}
483
484static void pstore_unregister_kmsg(void)
485{
486 kmsg_dump_unregister(&pstore_dumper);
487}
488
489#ifdef CONFIG_PSTORE_CONSOLE
490static void pstore_console_write(struct console *con, const char *s, unsigned c)
491{
492 struct pstore_record record;
493
494 if (!c)
495 return;
496
497 pstore_record_init(&record, psinfo);
498 record.type = PSTORE_TYPE_CONSOLE;
499
500 record.buf = (char *)s;
501 record.size = c;
502 psinfo->write(&record);
503}
504
505static struct console pstore_console = {
506 .name = "pstore",
507 .write = pstore_console_write,
508 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
509 .index = -1,
510};
511
512static void pstore_register_console(void)
513{
514 register_console(&pstore_console);
515}
516
517static void pstore_unregister_console(void)
518{
519 unregister_console(&pstore_console);
520}
521#else
522static void pstore_register_console(void) {}
523static void pstore_unregister_console(void) {}
524#endif
525
526static int pstore_write_user_compat(struct pstore_record *record,
527 const char __user *buf)
528{
529 int ret = 0;
530
531 if (record->buf)
532 return -EINVAL;
533
534 record->buf = memdup_user(buf, record->size);
535 if (IS_ERR(record->buf)) {
536 ret = PTR_ERR(record->buf);
537 goto out;
538 }
539
540 ret = record->psi->write(record);
541
542 kfree(record->buf);
543out:
544 record->buf = NULL;
545
546 return unlikely(ret < 0) ? ret : record->size;
547}
548
549/*
550 * platform specific persistent storage driver registers with
551 * us here. If pstore is already mounted, call the platform
552 * read function right away to populate the file system. If not
553 * then the pstore mount code will call us later to fill out
554 * the file system.
555 */
556int pstore_register(struct pstore_info *psi)
557{
558 struct module *owner = psi->owner;
559
560 if (backend && strcmp(backend, psi->name)) {
561 pr_warn("ignoring unexpected backend '%s'\n", psi->name);
562 return -EPERM;
563 }
564
565 /* Sanity check flags. */
566 if (!psi->flags) {
567 pr_warn("backend '%s' must support at least one frontend\n",
568 psi->name);
569 return -EINVAL;
570 }
571
572 /* Check for required functions. */
573 if (!psi->read || !psi->write) {
574 pr_warn("backend '%s' must implement read() and write()\n",
575 psi->name);
576 return -EINVAL;
577 }
578
579 spin_lock(&pstore_lock);
580 if (psinfo) {
581 pr_warn("backend '%s' already loaded: ignoring '%s'\n",
582 psinfo->name, psi->name);
583 spin_unlock(&pstore_lock);
584 return -EBUSY;
585 }
586
587 if (!psi->write_user)
588 psi->write_user = pstore_write_user_compat;
589 psinfo = psi;
590 mutex_init(&psinfo->read_mutex);
591 sema_init(&psinfo->buf_lock, 1);
592 spin_unlock(&pstore_lock);
593
594 if (owner && !try_module_get(owner)) {
595 psinfo = NULL;
596 return -EINVAL;
597 }
598
599 if (psi->flags & PSTORE_FLAGS_DMESG)
600 allocate_buf_for_compression();
601
602 if (pstore_is_mounted())
603 pstore_get_records(0);
604
605 if (psi->flags & PSTORE_FLAGS_DMESG)
606 pstore_register_kmsg();
607 if (psi->flags & PSTORE_FLAGS_CONSOLE)
608 pstore_register_console();
609 if (psi->flags & PSTORE_FLAGS_FTRACE)
610 pstore_register_ftrace();
611 if (psi->flags & PSTORE_FLAGS_PMSG)
612 pstore_register_pmsg();
613
614 /* Start watching for new records, if desired. */
615 if (pstore_update_ms >= 0) {
616 pstore_timer.expires = jiffies +
617 msecs_to_jiffies(pstore_update_ms);
618 add_timer(&pstore_timer);
619 }
620
621 /*
622 * Update the module parameter backend, so it is visible
623 * through /sys/module/pstore/parameters/backend
624 */
625 backend = psi->name;
626
627 pr_info("Registered %s as persistent store backend\n", psi->name);
628
629 module_put(owner);
630
631 return 0;
632}
633EXPORT_SYMBOL_GPL(pstore_register);
634
635void pstore_unregister(struct pstore_info *psi)
636{
637 /* Stop timer and make sure all work has finished. */
638 pstore_update_ms = -1;
639 del_timer_sync(&pstore_timer);
640 flush_work(&pstore_work);
641
642 if (psi->flags & PSTORE_FLAGS_PMSG)
643 pstore_unregister_pmsg();
644 if (psi->flags & PSTORE_FLAGS_FTRACE)
645 pstore_unregister_ftrace();
646 if (psi->flags & PSTORE_FLAGS_CONSOLE)
647 pstore_unregister_console();
648 if (psi->flags & PSTORE_FLAGS_DMESG)
649 pstore_unregister_kmsg();
650
651 free_buf_for_compression();
652
653 psinfo = NULL;
654 backend = NULL;
655}
656EXPORT_SYMBOL_GPL(pstore_unregister);
657
658static void decompress_record(struct pstore_record *record)
659{
660 int ret;
661 int unzipped_len;
662 char *unzipped, *workspace;
663
664 if (!record->compressed)
665 return;
666
667 /* Only PSTORE_TYPE_DMESG support compression. */
668 if (record->type != PSTORE_TYPE_DMESG) {
669 pr_warn("ignored compressed record type %d\n", record->type);
670 return;
671 }
672
673 /* Missing compression buffer means compression was not initialized. */
674 if (!big_oops_buf) {
675 pr_warn("no decompression method initialized!\n");
676 return;
677 }
678
679 /* Allocate enough space to hold max decompression and ECC. */
680 unzipped_len = big_oops_buf_sz;
681 workspace = kmalloc(unzipped_len + record->ecc_notice_size,
682 GFP_KERNEL);
683 if (!workspace)
684 return;
685
686 /* After decompression "unzipped_len" is almost certainly smaller. */
687 ret = crypto_comp_decompress(tfm, record->buf, record->size,
688 workspace, &unzipped_len);
689 if (ret) {
690 pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
691 kfree(workspace);
692 return;
693 }
694
695 /* Append ECC notice to decompressed buffer. */
696 memcpy(workspace + unzipped_len, record->buf + record->size,
697 record->ecc_notice_size);
698
699 /* Copy decompressed contents into an minimum-sized allocation. */
700 unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
701 GFP_KERNEL);
702 kfree(workspace);
703 if (!unzipped)
704 return;
705
706 /* Swap out compressed contents with decompressed contents. */
707 kfree(record->buf);
708 record->buf = unzipped;
709 record->size = unzipped_len;
710 record->compressed = false;
711}
712
713/*
714 * Read all the records from one persistent store backend. Create
715 * files in our filesystem. Don't warn about -EEXIST errors
716 * when we are re-scanning the backing store looking to add new
717 * error records.
718 */
719void pstore_get_backend_records(struct pstore_info *psi,
720 struct dentry *root, int quiet)
721{
722 int failed = 0;
723 unsigned int stop_loop = 65536;
724
725 if (!psi || !root)
726 return;
727
728 mutex_lock(&psi->read_mutex);
729 if (psi->open && psi->open(psi))
730 goto out;
731
732 /*
733 * Backend callback read() allocates record.buf. decompress_record()
734 * may reallocate record.buf. On success, pstore_mkfile() will keep
735 * the record.buf, so free it only on failure.
736 */
737 for (; stop_loop; stop_loop--) {
738 struct pstore_record *record;
739 int rc;
740
741 record = kzalloc(sizeof(*record), GFP_KERNEL);
742 if (!record) {
743 pr_err("out of memory creating record\n");
744 break;
745 }
746 pstore_record_init(record, psi);
747
748 record->size = psi->read(record);
749
750 /* No more records left in backend? */
751 if (record->size <= 0) {
752 kfree(record);
753 break;
754 }
755
756 decompress_record(record);
757 rc = pstore_mkfile(root, record);
758 if (rc) {
759 /* pstore_mkfile() did not take record, so free it. */
760 kfree(record->buf);
761 kfree(record);
762 if (rc != -EEXIST || !quiet)
763 failed++;
764 }
765 }
766 if (psi->close)
767 psi->close(psi);
768out:
769 mutex_unlock(&psi->read_mutex);
770
771 if (failed)
772 pr_warn("failed to create %d record(s) from '%s'\n",
773 failed, psi->name);
774 if (!stop_loop)
775 pr_err("looping? Too many records seen from '%s'\n",
776 psi->name);
777}
778
779static void pstore_dowork(struct work_struct *work)
780{
781 pstore_get_records(1);
782}
783
784static void pstore_timefunc(struct timer_list *unused)
785{
786 if (pstore_new_entry) {
787 pstore_new_entry = 0;
788 schedule_work(&pstore_work);
789 }
790
791 if (pstore_update_ms >= 0)
792 mod_timer(&pstore_timer,
793 jiffies + msecs_to_jiffies(pstore_update_ms));
794}
795
796void __init pstore_choose_compression(void)
797{
798 const struct pstore_zbackend *step;
799
800 if (!compress)
801 return;
802
803 for (step = zbackends; step->name; step++) {
804 if (!strcmp(compress, step->name)) {
805 zbackend = step;
806 return;
807 }
808 }
809}
810
811static int __init pstore_init(void)
812{
813 int ret;
814
815 pstore_choose_compression();
816
817 /*
818 * Check if any pstore backends registered earlier but did not
819 * initialize compression because crypto was not ready. If so,
820 * initialize compression now.
821 */
822 allocate_buf_for_compression();
823
824 ret = pstore_init_fs();
825 if (ret)
826 return ret;
827
828 return 0;
829}
830late_initcall(pstore_init);
831
832static void __exit pstore_exit(void)
833{
834 pstore_exit_fs();
835}
836module_exit(pstore_exit)
837
838module_param(compress, charp, 0444);
839MODULE_PARM_DESC(compress, "Pstore compression to use");
840
841module_param(backend, charp, 0444);
842MODULE_PARM_DESC(backend, "Pstore backend to use");
843
844MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
845MODULE_LICENSE("GPL");
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");