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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 may not be 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 * psinfo_lock protects "psinfo" during calls to
73 * pstore_register(), pstore_unregister(), and
74 * the filesystem mount/unmount routines.
75 */
76static DEFINE_MUTEX(psinfo_lock);
77struct pstore_info *psinfo;
78
79static char *backend;
80module_param(backend, charp, 0444);
81MODULE_PARM_DESC(backend, "specific backend to use");
82
83static char *compress =
84#ifdef CONFIG_PSTORE_COMPRESS_DEFAULT
85 CONFIG_PSTORE_COMPRESS_DEFAULT;
86#else
87 NULL;
88#endif
89module_param(compress, charp, 0444);
90MODULE_PARM_DESC(compress, "compression to use");
91
92/* How much of the kernel log to snapshot */
93unsigned long kmsg_bytes = CONFIG_PSTORE_DEFAULT_KMSG_BYTES;
94module_param(kmsg_bytes, ulong, 0444);
95MODULE_PARM_DESC(kmsg_bytes, "amount of kernel log to snapshot (in bytes)");
96
97/* Compression parameters */
98static struct crypto_comp *tfm;
99
100struct pstore_zbackend {
101 int (*zbufsize)(size_t size);
102 const char *name;
103};
104
105static char *big_oops_buf;
106static size_t big_oops_buf_sz;
107
108void pstore_set_kmsg_bytes(int bytes)
109{
110 kmsg_bytes = bytes;
111}
112
113/* Tag each group of saved records with a sequence number */
114static int oopscount;
115
116const char *pstore_type_to_name(enum pstore_type_id type)
117{
118 BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
119
120 if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
121 return "unknown";
122
123 return pstore_type_names[type];
124}
125EXPORT_SYMBOL_GPL(pstore_type_to_name);
126
127enum pstore_type_id pstore_name_to_type(const char *name)
128{
129 int i;
130
131 for (i = 0; i < PSTORE_TYPE_MAX; i++) {
132 if (!strcmp(pstore_type_names[i], name))
133 return i;
134 }
135
136 return PSTORE_TYPE_MAX;
137}
138EXPORT_SYMBOL_GPL(pstore_name_to_type);
139
140static void pstore_timer_kick(void)
141{
142 if (pstore_update_ms < 0)
143 return;
144
145 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
146}
147
148static bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
149{
150 /*
151 * In case of NMI path, pstore shouldn't be blocked
152 * regardless of reason.
153 */
154 if (in_nmi())
155 return true;
156
157 switch (reason) {
158 /* In panic case, other cpus are stopped by smp_send_stop(). */
159 case KMSG_DUMP_PANIC:
160 /*
161 * Emergency restart shouldn't be blocked by spinning on
162 * pstore_info::buf_lock.
163 */
164 case KMSG_DUMP_EMERG:
165 return true;
166 default:
167 return false;
168 }
169}
170
171#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
172static int zbufsize_deflate(size_t size)
173{
174 size_t cmpr;
175
176 switch (size) {
177 /* buffer range for efivars */
178 case 1000 ... 2000:
179 cmpr = 56;
180 break;
181 case 2001 ... 3000:
182 cmpr = 54;
183 break;
184 case 3001 ... 3999:
185 cmpr = 52;
186 break;
187 /* buffer range for nvram, erst */
188 case 4000 ... 10000:
189 cmpr = 45;
190 break;
191 default:
192 cmpr = 60;
193 break;
194 }
195
196 return (size * 100) / cmpr;
197}
198#endif
199
200#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
201static int zbufsize_lzo(size_t size)
202{
203 return lzo1x_worst_compress(size);
204}
205#endif
206
207#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
208static int zbufsize_lz4(size_t size)
209{
210 return LZ4_compressBound(size);
211}
212#endif
213
214#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
215static int zbufsize_842(size_t size)
216{
217 return size;
218}
219#endif
220
221#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
222static int zbufsize_zstd(size_t size)
223{
224 return zstd_compress_bound(size);
225}
226#endif
227
228static const struct pstore_zbackend *zbackend __ro_after_init;
229
230static const struct pstore_zbackend zbackends[] = {
231#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
232 {
233 .zbufsize = zbufsize_deflate,
234 .name = "deflate",
235 },
236#endif
237#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
238 {
239 .zbufsize = zbufsize_lzo,
240 .name = "lzo",
241 },
242#endif
243#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS)
244 {
245 .zbufsize = zbufsize_lz4,
246 .name = "lz4",
247 },
248#endif
249#if IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
250 {
251 .zbufsize = zbufsize_lz4,
252 .name = "lz4hc",
253 },
254#endif
255#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
256 {
257 .zbufsize = zbufsize_842,
258 .name = "842",
259 },
260#endif
261#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
262 {
263 .zbufsize = zbufsize_zstd,
264 .name = "zstd",
265 },
266#endif
267 { }
268};
269
270static int pstore_compress(const void *in, void *out,
271 unsigned int inlen, unsigned int outlen)
272{
273 int ret;
274
275 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS))
276 return -EINVAL;
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 struct kmsg_dump_iter iter;
392 unsigned long total = 0;
393 const char *why;
394 unsigned int part = 1;
395 unsigned long flags = 0;
396 int saved_ret = 0;
397 int ret;
398
399 why = kmsg_dump_reason_str(reason);
400
401 if (pstore_cannot_block_path(reason)) {
402 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
403 pr_err("dump skipped in %s path because of concurrent dump\n",
404 in_nmi() ? "NMI" : why);
405 return;
406 }
407 } else {
408 spin_lock_irqsave(&psinfo->buf_lock, flags);
409 }
410
411 kmsg_dump_rewind(&iter);
412
413 oopscount++;
414 while (total < kmsg_bytes) {
415 char *dst;
416 size_t dst_size;
417 int header_size;
418 int zipped_len = -1;
419 size_t dump_size;
420 struct pstore_record record;
421
422 pstore_record_init(&record, psinfo);
423 record.type = PSTORE_TYPE_DMESG;
424 record.count = oopscount;
425 record.reason = reason;
426 record.part = part;
427 record.buf = psinfo->buf;
428
429 if (big_oops_buf) {
430 dst = big_oops_buf;
431 dst_size = big_oops_buf_sz;
432 } else {
433 dst = psinfo->buf;
434 dst_size = psinfo->bufsize;
435 }
436
437 /* Write dump header. */
438 header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
439 oopscount, part);
440 dst_size -= header_size;
441
442 /* Write dump contents. */
443 if (!kmsg_dump_get_buffer(&iter, true, dst + header_size,
444 dst_size, &dump_size))
445 break;
446
447 if (big_oops_buf) {
448 zipped_len = pstore_compress(dst, psinfo->buf,
449 header_size + dump_size,
450 psinfo->bufsize);
451
452 if (zipped_len > 0) {
453 record.compressed = true;
454 record.size = zipped_len;
455 } else {
456 record.size = copy_kmsg_to_buffer(header_size,
457 dump_size);
458 }
459 } else {
460 record.size = header_size + dump_size;
461 }
462
463 ret = psinfo->write(&record);
464 if (ret == 0 && reason == KMSG_DUMP_OOPS) {
465 pstore_new_entry = 1;
466 pstore_timer_kick();
467 } else {
468 /* Preserve only the first non-zero returned value. */
469 if (!saved_ret)
470 saved_ret = ret;
471 }
472
473 total += record.size;
474 part++;
475 }
476 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
477
478 if (saved_ret) {
479 pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,
480 saved_ret);
481 }
482}
483
484static struct kmsg_dumper pstore_dumper = {
485 .dump = pstore_dump,
486};
487
488/*
489 * Register with kmsg_dump to save last part of console log on panic.
490 */
491static void pstore_register_kmsg(void)
492{
493 kmsg_dump_register(&pstore_dumper);
494}
495
496static void pstore_unregister_kmsg(void)
497{
498 kmsg_dump_unregister(&pstore_dumper);
499}
500
501#ifdef CONFIG_PSTORE_CONSOLE
502static void pstore_console_write(struct console *con, const char *s, unsigned c)
503{
504 struct pstore_record record;
505
506 if (!c)
507 return;
508
509 pstore_record_init(&record, psinfo);
510 record.type = PSTORE_TYPE_CONSOLE;
511
512 record.buf = (char *)s;
513 record.size = c;
514 psinfo->write(&record);
515}
516
517static struct console pstore_console = {
518 .write = pstore_console_write,
519 .index = -1,
520};
521
522static void pstore_register_console(void)
523{
524 /* Show which backend is going to get console writes. */
525 strscpy(pstore_console.name, psinfo->name,
526 sizeof(pstore_console.name));
527 /*
528 * Always initialize flags here since prior unregister_console()
529 * calls may have changed settings (specifically CON_ENABLED).
530 */
531 pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME;
532 register_console(&pstore_console);
533}
534
535static void pstore_unregister_console(void)
536{
537 unregister_console(&pstore_console);
538}
539#else
540static void pstore_register_console(void) {}
541static void pstore_unregister_console(void) {}
542#endif
543
544static int pstore_write_user_compat(struct pstore_record *record,
545 const char __user *buf)
546{
547 int ret = 0;
548
549 if (record->buf)
550 return -EINVAL;
551
552 record->buf = memdup_user(buf, record->size);
553 if (IS_ERR(record->buf)) {
554 ret = PTR_ERR(record->buf);
555 goto out;
556 }
557
558 ret = record->psi->write(record);
559
560 kfree(record->buf);
561out:
562 record->buf = NULL;
563
564 return unlikely(ret < 0) ? ret : record->size;
565}
566
567/*
568 * platform specific persistent storage driver registers with
569 * us here. If pstore is already mounted, call the platform
570 * read function right away to populate the file system. If not
571 * then the pstore mount code will call us later to fill out
572 * the file system.
573 */
574int pstore_register(struct pstore_info *psi)
575{
576 if (backend && strcmp(backend, psi->name)) {
577 pr_warn("backend '%s' already in use: ignoring '%s'\n",
578 backend, psi->name);
579 return -EBUSY;
580 }
581
582 /* Sanity check flags. */
583 if (!psi->flags) {
584 pr_warn("backend '%s' must support at least one frontend\n",
585 psi->name);
586 return -EINVAL;
587 }
588
589 /* Check for required functions. */
590 if (!psi->read || !psi->write) {
591 pr_warn("backend '%s' must implement read() and write()\n",
592 psi->name);
593 return -EINVAL;
594 }
595
596 mutex_lock(&psinfo_lock);
597 if (psinfo) {
598 pr_warn("backend '%s' already loaded: ignoring '%s'\n",
599 psinfo->name, psi->name);
600 mutex_unlock(&psinfo_lock);
601 return -EBUSY;
602 }
603
604 if (!psi->write_user)
605 psi->write_user = pstore_write_user_compat;
606 psinfo = psi;
607 mutex_init(&psinfo->read_mutex);
608 spin_lock_init(&psinfo->buf_lock);
609
610 if (psi->flags & PSTORE_FLAGS_DMESG)
611 allocate_buf_for_compression();
612
613 pstore_get_records(0);
614
615 if (psi->flags & PSTORE_FLAGS_DMESG) {
616 pstore_dumper.max_reason = psinfo->max_reason;
617 pstore_register_kmsg();
618 }
619 if (psi->flags & PSTORE_FLAGS_CONSOLE)
620 pstore_register_console();
621 if (psi->flags & PSTORE_FLAGS_FTRACE)
622 pstore_register_ftrace();
623 if (psi->flags & PSTORE_FLAGS_PMSG)
624 pstore_register_pmsg();
625
626 /* Start watching for new records, if desired. */
627 pstore_timer_kick();
628
629 /*
630 * Update the module parameter backend, so it is visible
631 * through /sys/module/pstore/parameters/backend
632 */
633 backend = kstrdup(psi->name, GFP_KERNEL);
634
635 pr_info("Registered %s as persistent store backend\n", psi->name);
636
637 mutex_unlock(&psinfo_lock);
638 return 0;
639}
640EXPORT_SYMBOL_GPL(pstore_register);
641
642void pstore_unregister(struct pstore_info *psi)
643{
644 /* It's okay to unregister nothing. */
645 if (!psi)
646 return;
647
648 mutex_lock(&psinfo_lock);
649
650 /* Only one backend can be registered at a time. */
651 if (WARN_ON(psi != psinfo)) {
652 mutex_unlock(&psinfo_lock);
653 return;
654 }
655
656 /* Unregister all callbacks. */
657 if (psi->flags & PSTORE_FLAGS_PMSG)
658 pstore_unregister_pmsg();
659 if (psi->flags & PSTORE_FLAGS_FTRACE)
660 pstore_unregister_ftrace();
661 if (psi->flags & PSTORE_FLAGS_CONSOLE)
662 pstore_unregister_console();
663 if (psi->flags & PSTORE_FLAGS_DMESG)
664 pstore_unregister_kmsg();
665
666 /* Stop timer and make sure all work has finished. */
667 del_timer_sync(&pstore_timer);
668 flush_work(&pstore_work);
669
670 /* Remove all backend records from filesystem tree. */
671 pstore_put_backend_records(psi);
672
673 free_buf_for_compression();
674
675 psinfo = NULL;
676 kfree(backend);
677 backend = NULL;
678
679 pr_info("Unregistered %s as persistent store backend\n", psi->name);
680 mutex_unlock(&psinfo_lock);
681}
682EXPORT_SYMBOL_GPL(pstore_unregister);
683
684static void decompress_record(struct pstore_record *record)
685{
686 int ret;
687 int unzipped_len;
688 char *unzipped, *workspace;
689
690 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
691 return;
692
693 /* Only PSTORE_TYPE_DMESG support compression. */
694 if (record->type != PSTORE_TYPE_DMESG) {
695 pr_warn("ignored compressed record type %d\n", record->type);
696 return;
697 }
698
699 /* Missing compression buffer means compression was not initialized. */
700 if (!big_oops_buf) {
701 pr_warn("no decompression method initialized!\n");
702 return;
703 }
704
705 /* Allocate enough space to hold max decompression and ECC. */
706 unzipped_len = big_oops_buf_sz;
707 workspace = kmalloc(unzipped_len + record->ecc_notice_size,
708 GFP_KERNEL);
709 if (!workspace)
710 return;
711
712 /* After decompression "unzipped_len" is almost certainly smaller. */
713 ret = crypto_comp_decompress(tfm, record->buf, record->size,
714 workspace, &unzipped_len);
715 if (ret) {
716 pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
717 kfree(workspace);
718 return;
719 }
720
721 /* Append ECC notice to decompressed buffer. */
722 memcpy(workspace + unzipped_len, record->buf + record->size,
723 record->ecc_notice_size);
724
725 /* Copy decompressed contents into an minimum-sized allocation. */
726 unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
727 GFP_KERNEL);
728 kfree(workspace);
729 if (!unzipped)
730 return;
731
732 /* Swap out compressed contents with decompressed contents. */
733 kfree(record->buf);
734 record->buf = unzipped;
735 record->size = unzipped_len;
736 record->compressed = false;
737}
738
739/*
740 * Read all the records from one persistent store backend. Create
741 * files in our filesystem. Don't warn about -EEXIST errors
742 * when we are re-scanning the backing store looking to add new
743 * error records.
744 */
745void pstore_get_backend_records(struct pstore_info *psi,
746 struct dentry *root, int quiet)
747{
748 int failed = 0;
749 unsigned int stop_loop = 65536;
750
751 if (!psi || !root)
752 return;
753
754 mutex_lock(&psi->read_mutex);
755 if (psi->open && psi->open(psi))
756 goto out;
757
758 /*
759 * Backend callback read() allocates record.buf. decompress_record()
760 * may reallocate record.buf. On success, pstore_mkfile() will keep
761 * the record.buf, so free it only on failure.
762 */
763 for (; stop_loop; stop_loop--) {
764 struct pstore_record *record;
765 int rc;
766
767 record = kzalloc(sizeof(*record), GFP_KERNEL);
768 if (!record) {
769 pr_err("out of memory creating record\n");
770 break;
771 }
772 pstore_record_init(record, psi);
773
774 record->size = psi->read(record);
775
776 /* No more records left in backend? */
777 if (record->size <= 0) {
778 kfree(record);
779 break;
780 }
781
782 decompress_record(record);
783 rc = pstore_mkfile(root, record);
784 if (rc) {
785 /* pstore_mkfile() did not take record, so free it. */
786 kfree(record->buf);
787 kfree(record->priv);
788 kfree(record);
789 if (rc != -EEXIST || !quiet)
790 failed++;
791 }
792 }
793 if (psi->close)
794 psi->close(psi);
795out:
796 mutex_unlock(&psi->read_mutex);
797
798 if (failed)
799 pr_warn("failed to create %d record(s) from '%s'\n",
800 failed, psi->name);
801 if (!stop_loop)
802 pr_err("looping? Too many records seen from '%s'\n",
803 psi->name);
804}
805
806static void pstore_dowork(struct work_struct *work)
807{
808 pstore_get_records(1);
809}
810
811static void pstore_timefunc(struct timer_list *unused)
812{
813 if (pstore_new_entry) {
814 pstore_new_entry = 0;
815 schedule_work(&pstore_work);
816 }
817
818 pstore_timer_kick();
819}
820
821static void __init pstore_choose_compression(void)
822{
823 const struct pstore_zbackend *step;
824
825 if (!compress)
826 return;
827
828 for (step = zbackends; step->name; step++) {
829 if (!strcmp(compress, step->name)) {
830 zbackend = step;
831 return;
832 }
833 }
834}
835
836static int __init pstore_init(void)
837{
838 int ret;
839
840 pstore_choose_compression();
841
842 /*
843 * Check if any pstore backends registered earlier but did not
844 * initialize compression because crypto was not ready. If so,
845 * initialize compression now.
846 */
847 allocate_buf_for_compression();
848
849 ret = pstore_init_fs();
850 if (ret)
851 free_buf_for_compression();
852
853 return ret;
854}
855late_initcall(pstore_init);
856
857static void __exit pstore_exit(void)
858{
859 pstore_exit_fs();
860}
861module_exit(pstore_exit)
862
863MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
864MODULE_LICENSE("GPL");
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 may not be 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 * psinfo_lock protects "psinfo" during calls to
73 * pstore_register(), pstore_unregister(), and
74 * the filesystem mount/unmount routines.
75 */
76static DEFINE_MUTEX(psinfo_lock);
77struct pstore_info *psinfo;
78
79static char *backend;
80module_param(backend, charp, 0444);
81MODULE_PARM_DESC(backend, "specific backend to use");
82
83static char *compress =
84#ifdef CONFIG_PSTORE_COMPRESS_DEFAULT
85 CONFIG_PSTORE_COMPRESS_DEFAULT;
86#else
87 NULL;
88#endif
89module_param(compress, charp, 0444);
90MODULE_PARM_DESC(compress, "compression to use");
91
92/* Compression parameters */
93static struct crypto_comp *tfm;
94
95struct pstore_zbackend {
96 int (*zbufsize)(size_t size);
97 const char *name;
98};
99
100static char *big_oops_buf;
101static size_t big_oops_buf_sz;
102
103/* How much of the console log to snapshot */
104unsigned long kmsg_bytes = PSTORE_DEFAULT_KMSG_BYTES;
105
106void pstore_set_kmsg_bytes(int bytes)
107{
108 kmsg_bytes = bytes;
109}
110
111/* Tag each group of saved records with a sequence number */
112static int oopscount;
113
114const char *pstore_type_to_name(enum pstore_type_id type)
115{
116 BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
117
118 if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
119 return "unknown";
120
121 return pstore_type_names[type];
122}
123EXPORT_SYMBOL_GPL(pstore_type_to_name);
124
125enum pstore_type_id pstore_name_to_type(const char *name)
126{
127 int i;
128
129 for (i = 0; i < PSTORE_TYPE_MAX; i++) {
130 if (!strcmp(pstore_type_names[i], name))
131 return i;
132 }
133
134 return PSTORE_TYPE_MAX;
135}
136EXPORT_SYMBOL_GPL(pstore_name_to_type);
137
138static void pstore_timer_kick(void)
139{
140 if (pstore_update_ms < 0)
141 return;
142
143 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
144}
145
146/*
147 * Should pstore_dump() wait for a concurrent pstore_dump()? If
148 * not, the current pstore_dump() will report a failure to dump
149 * and return.
150 */
151static bool pstore_cannot_wait(enum kmsg_dump_reason reason)
152{
153 /* In NMI path, pstore shouldn't block regardless of reason. */
154 if (in_nmi())
155 return true;
156
157 switch (reason) {
158 /* In panic case, other cpus are stopped by smp_send_stop(). */
159 case KMSG_DUMP_PANIC:
160 /* Emergency restart shouldn't be blocked. */
161 case KMSG_DUMP_EMERG:
162 return true;
163 default:
164 return false;
165 }
166}
167
168#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
169static int zbufsize_deflate(size_t size)
170{
171 size_t cmpr;
172
173 switch (size) {
174 /* buffer range for efivars */
175 case 1000 ... 2000:
176 cmpr = 56;
177 break;
178 case 2001 ... 3000:
179 cmpr = 54;
180 break;
181 case 3001 ... 3999:
182 cmpr = 52;
183 break;
184 /* buffer range for nvram, erst */
185 case 4000 ... 10000:
186 cmpr = 45;
187 break;
188 default:
189 cmpr = 60;
190 break;
191 }
192
193 return (size * 100) / cmpr;
194}
195#endif
196
197#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
198static int zbufsize_lzo(size_t size)
199{
200 return lzo1x_worst_compress(size);
201}
202#endif
203
204#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
205static int zbufsize_lz4(size_t size)
206{
207 return LZ4_compressBound(size);
208}
209#endif
210
211#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
212static int zbufsize_842(size_t size)
213{
214 return size;
215}
216#endif
217
218#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
219static int zbufsize_zstd(size_t size)
220{
221 return ZSTD_compressBound(size);
222}
223#endif
224
225static const struct pstore_zbackend *zbackend __ro_after_init;
226
227static const struct pstore_zbackend zbackends[] = {
228#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
229 {
230 .zbufsize = zbufsize_deflate,
231 .name = "deflate",
232 },
233#endif
234#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
235 {
236 .zbufsize = zbufsize_lzo,
237 .name = "lzo",
238 },
239#endif
240#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS)
241 {
242 .zbufsize = zbufsize_lz4,
243 .name = "lz4",
244 },
245#endif
246#if IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
247 {
248 .zbufsize = zbufsize_lz4,
249 .name = "lz4hc",
250 },
251#endif
252#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
253 {
254 .zbufsize = zbufsize_842,
255 .name = "842",
256 },
257#endif
258#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
259 {
260 .zbufsize = zbufsize_zstd,
261 .name = "zstd",
262 },
263#endif
264 { }
265};
266
267static int pstore_compress(const void *in, void *out,
268 unsigned int inlen, unsigned int outlen)
269{
270 int ret;
271
272 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESSION))
273 return -EINVAL;
274
275 ret = crypto_comp_compress(tfm, in, inlen, out, &outlen);
276 if (ret) {
277 pr_err("crypto_comp_compress failed, ret = %d!\n", ret);
278 return ret;
279 }
280
281 return outlen;
282}
283
284static void allocate_buf_for_compression(void)
285{
286 struct crypto_comp *ctx;
287 int size;
288 char *buf;
289
290 /* Skip if not built-in or compression backend not selected yet. */
291 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
292 return;
293
294 /* Skip if no pstore backend yet or compression init already done. */
295 if (!psinfo || tfm)
296 return;
297
298 if (!crypto_has_comp(zbackend->name, 0, 0)) {
299 pr_err("Unknown compression: %s\n", zbackend->name);
300 return;
301 }
302
303 size = zbackend->zbufsize(psinfo->bufsize);
304 if (size <= 0) {
305 pr_err("Invalid compression size for %s: %d\n",
306 zbackend->name, size);
307 return;
308 }
309
310 buf = kmalloc(size, GFP_KERNEL);
311 if (!buf) {
312 pr_err("Failed %d byte compression buffer allocation for: %s\n",
313 size, zbackend->name);
314 return;
315 }
316
317 ctx = crypto_alloc_comp(zbackend->name, 0, 0);
318 if (IS_ERR_OR_NULL(ctx)) {
319 kfree(buf);
320 pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
321 PTR_ERR(ctx));
322 return;
323 }
324
325 /* A non-NULL big_oops_buf indicates compression is available. */
326 tfm = ctx;
327 big_oops_buf_sz = size;
328 big_oops_buf = buf;
329
330 pr_info("Using crash dump compression: %s\n", zbackend->name);
331}
332
333static void free_buf_for_compression(void)
334{
335 if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) {
336 crypto_free_comp(tfm);
337 tfm = NULL;
338 }
339 kfree(big_oops_buf);
340 big_oops_buf = NULL;
341 big_oops_buf_sz = 0;
342}
343
344/*
345 * Called when compression fails, since the printk buffer
346 * would be fetched for compression calling it again when
347 * compression fails would have moved the iterator of
348 * printk buffer which results in fetching old contents.
349 * Copy the recent messages from big_oops_buf to psinfo->buf
350 */
351static size_t copy_kmsg_to_buffer(int hsize, size_t len)
352{
353 size_t total_len;
354 size_t diff;
355
356 total_len = hsize + len;
357
358 if (total_len > psinfo->bufsize) {
359 diff = total_len - psinfo->bufsize + hsize;
360 memcpy(psinfo->buf, big_oops_buf, hsize);
361 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
362 psinfo->bufsize - hsize);
363 total_len = psinfo->bufsize;
364 } else
365 memcpy(psinfo->buf, big_oops_buf, total_len);
366
367 return total_len;
368}
369
370void pstore_record_init(struct pstore_record *record,
371 struct pstore_info *psinfo)
372{
373 memset(record, 0, sizeof(*record));
374
375 record->psi = psinfo;
376
377 /* Report zeroed timestamp if called before timekeeping has resumed. */
378 record->time = ns_to_timespec64(ktime_get_real_fast_ns());
379}
380
381/*
382 * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
383 * end of the buffer.
384 */
385static void pstore_dump(struct kmsg_dumper *dumper,
386 enum kmsg_dump_reason reason)
387{
388 unsigned long total = 0;
389 const char *why;
390 unsigned int part = 1;
391 int ret;
392
393 why = kmsg_dump_reason_str(reason);
394
395 if (down_trylock(&psinfo->buf_lock)) {
396 /* Failed to acquire lock: give up if we cannot wait. */
397 if (pstore_cannot_wait(reason)) {
398 pr_err("dump skipped in %s path: may corrupt error record\n",
399 in_nmi() ? "NMI" : why);
400 return;
401 }
402 if (down_interruptible(&psinfo->buf_lock)) {
403 pr_err("could not grab semaphore?!\n");
404 return;
405 }
406 }
407
408 oopscount++;
409 while (total < kmsg_bytes) {
410 char *dst;
411 size_t dst_size;
412 int header_size;
413 int zipped_len = -1;
414 size_t dump_size;
415 struct pstore_record record;
416
417 pstore_record_init(&record, psinfo);
418 record.type = PSTORE_TYPE_DMESG;
419 record.count = oopscount;
420 record.reason = reason;
421 record.part = part;
422 record.buf = psinfo->buf;
423
424 if (big_oops_buf) {
425 dst = big_oops_buf;
426 dst_size = big_oops_buf_sz;
427 } else {
428 dst = psinfo->buf;
429 dst_size = psinfo->bufsize;
430 }
431
432 /* Write dump header. */
433 header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
434 oopscount, part);
435 dst_size -= header_size;
436
437 /* Write dump contents. */
438 if (!kmsg_dump_get_buffer(dumper, true, dst + header_size,
439 dst_size, &dump_size))
440 break;
441
442 if (big_oops_buf) {
443 zipped_len = pstore_compress(dst, psinfo->buf,
444 header_size + dump_size,
445 psinfo->bufsize);
446
447 if (zipped_len > 0) {
448 record.compressed = true;
449 record.size = zipped_len;
450 } else {
451 record.size = copy_kmsg_to_buffer(header_size,
452 dump_size);
453 }
454 } else {
455 record.size = header_size + dump_size;
456 }
457
458 ret = psinfo->write(&record);
459 if (ret == 0 && reason == KMSG_DUMP_OOPS) {
460 pstore_new_entry = 1;
461 pstore_timer_kick();
462 }
463
464 total += record.size;
465 part++;
466 }
467
468 up(&psinfo->buf_lock);
469}
470
471static struct kmsg_dumper pstore_dumper = {
472 .dump = pstore_dump,
473};
474
475/*
476 * Register with kmsg_dump to save last part of console log on panic.
477 */
478static void pstore_register_kmsg(void)
479{
480 kmsg_dump_register(&pstore_dumper);
481}
482
483static void pstore_unregister_kmsg(void)
484{
485 kmsg_dump_unregister(&pstore_dumper);
486}
487
488#ifdef CONFIG_PSTORE_CONSOLE
489static void pstore_console_write(struct console *con, const char *s, unsigned c)
490{
491 struct pstore_record record;
492
493 if (!c)
494 return;
495
496 pstore_record_init(&record, psinfo);
497 record.type = PSTORE_TYPE_CONSOLE;
498
499 record.buf = (char *)s;
500 record.size = c;
501 psinfo->write(&record);
502}
503
504static struct console pstore_console = {
505 .write = pstore_console_write,
506 .index = -1,
507};
508
509static void pstore_register_console(void)
510{
511 /* Show which backend is going to get console writes. */
512 strscpy(pstore_console.name, psinfo->name,
513 sizeof(pstore_console.name));
514 /*
515 * Always initialize flags here since prior unregister_console()
516 * calls may have changed settings (specifically CON_ENABLED).
517 */
518 pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME;
519 register_console(&pstore_console);
520}
521
522static void pstore_unregister_console(void)
523{
524 unregister_console(&pstore_console);
525}
526#else
527static void pstore_register_console(void) {}
528static void pstore_unregister_console(void) {}
529#endif
530
531static int pstore_write_user_compat(struct pstore_record *record,
532 const char __user *buf)
533{
534 int ret = 0;
535
536 if (record->buf)
537 return -EINVAL;
538
539 record->buf = memdup_user(buf, record->size);
540 if (IS_ERR(record->buf)) {
541 ret = PTR_ERR(record->buf);
542 goto out;
543 }
544
545 ret = record->psi->write(record);
546
547 kfree(record->buf);
548out:
549 record->buf = NULL;
550
551 return unlikely(ret < 0) ? ret : record->size;
552}
553
554/*
555 * platform specific persistent storage driver registers with
556 * us here. If pstore is already mounted, call the platform
557 * read function right away to populate the file system. If not
558 * then the pstore mount code will call us later to fill out
559 * the file system.
560 */
561int pstore_register(struct pstore_info *psi)
562{
563 if (backend && strcmp(backend, psi->name)) {
564 pr_warn("ignoring unexpected backend '%s'\n", psi->name);
565 return -EPERM;
566 }
567
568 /* Sanity check flags. */
569 if (!psi->flags) {
570 pr_warn("backend '%s' must support at least one frontend\n",
571 psi->name);
572 return -EINVAL;
573 }
574
575 /* Check for required functions. */
576 if (!psi->read || !psi->write) {
577 pr_warn("backend '%s' must implement read() and write()\n",
578 psi->name);
579 return -EINVAL;
580 }
581
582 mutex_lock(&psinfo_lock);
583 if (psinfo) {
584 pr_warn("backend '%s' already loaded: ignoring '%s'\n",
585 psinfo->name, psi->name);
586 mutex_unlock(&psinfo_lock);
587 return -EBUSY;
588 }
589
590 if (!psi->write_user)
591 psi->write_user = pstore_write_user_compat;
592 psinfo = psi;
593 mutex_init(&psinfo->read_mutex);
594 sema_init(&psinfo->buf_lock, 1);
595
596 if (psi->flags & PSTORE_FLAGS_DMESG)
597 allocate_buf_for_compression();
598
599 pstore_get_records(0);
600
601 if (psi->flags & PSTORE_FLAGS_DMESG) {
602 pstore_dumper.max_reason = psinfo->max_reason;
603 pstore_register_kmsg();
604 }
605 if (psi->flags & PSTORE_FLAGS_CONSOLE)
606 pstore_register_console();
607 if (psi->flags & PSTORE_FLAGS_FTRACE)
608 pstore_register_ftrace();
609 if (psi->flags & PSTORE_FLAGS_PMSG)
610 pstore_register_pmsg();
611
612 /* Start watching for new records, if desired. */
613 pstore_timer_kick();
614
615 /*
616 * Update the module parameter backend, so it is visible
617 * through /sys/module/pstore/parameters/backend
618 */
619 backend = kstrdup(psi->name, GFP_KERNEL);
620
621 pr_info("Registered %s as persistent store backend\n", psi->name);
622
623 mutex_unlock(&psinfo_lock);
624 return 0;
625}
626EXPORT_SYMBOL_GPL(pstore_register);
627
628void pstore_unregister(struct pstore_info *psi)
629{
630 /* It's okay to unregister nothing. */
631 if (!psi)
632 return;
633
634 mutex_lock(&psinfo_lock);
635
636 /* Only one backend can be registered at a time. */
637 if (WARN_ON(psi != psinfo)) {
638 mutex_unlock(&psinfo_lock);
639 return;
640 }
641
642 /* Unregister all callbacks. */
643 if (psi->flags & PSTORE_FLAGS_PMSG)
644 pstore_unregister_pmsg();
645 if (psi->flags & PSTORE_FLAGS_FTRACE)
646 pstore_unregister_ftrace();
647 if (psi->flags & PSTORE_FLAGS_CONSOLE)
648 pstore_unregister_console();
649 if (psi->flags & PSTORE_FLAGS_DMESG)
650 pstore_unregister_kmsg();
651
652 /* Stop timer and make sure all work has finished. */
653 del_timer_sync(&pstore_timer);
654 flush_work(&pstore_work);
655
656 /* Remove all backend records from filesystem tree. */
657 pstore_put_backend_records(psi);
658
659 free_buf_for_compression();
660
661 psinfo = NULL;
662 kfree(backend);
663 backend = NULL;
664 mutex_unlock(&psinfo_lock);
665}
666EXPORT_SYMBOL_GPL(pstore_unregister);
667
668static void decompress_record(struct pstore_record *record)
669{
670 int ret;
671 int unzipped_len;
672 char *unzipped, *workspace;
673
674 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESSION) || !record->compressed)
675 return;
676
677 /* Only PSTORE_TYPE_DMESG support compression. */
678 if (record->type != PSTORE_TYPE_DMESG) {
679 pr_warn("ignored compressed record type %d\n", record->type);
680 return;
681 }
682
683 /* Missing compression buffer means compression was not initialized. */
684 if (!big_oops_buf) {
685 pr_warn("no decompression method initialized!\n");
686 return;
687 }
688
689 /* Allocate enough space to hold max decompression and ECC. */
690 unzipped_len = big_oops_buf_sz;
691 workspace = kmalloc(unzipped_len + record->ecc_notice_size,
692 GFP_KERNEL);
693 if (!workspace)
694 return;
695
696 /* After decompression "unzipped_len" is almost certainly smaller. */
697 ret = crypto_comp_decompress(tfm, record->buf, record->size,
698 workspace, &unzipped_len);
699 if (ret) {
700 pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
701 kfree(workspace);
702 return;
703 }
704
705 /* Append ECC notice to decompressed buffer. */
706 memcpy(workspace + unzipped_len, record->buf + record->size,
707 record->ecc_notice_size);
708
709 /* Copy decompressed contents into an minimum-sized allocation. */
710 unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
711 GFP_KERNEL);
712 kfree(workspace);
713 if (!unzipped)
714 return;
715
716 /* Swap out compressed contents with decompressed contents. */
717 kfree(record->buf);
718 record->buf = unzipped;
719 record->size = unzipped_len;
720 record->compressed = false;
721}
722
723/*
724 * Read all the records from one persistent store backend. Create
725 * files in our filesystem. Don't warn about -EEXIST errors
726 * when we are re-scanning the backing store looking to add new
727 * error records.
728 */
729void pstore_get_backend_records(struct pstore_info *psi,
730 struct dentry *root, int quiet)
731{
732 int failed = 0;
733 unsigned int stop_loop = 65536;
734
735 if (!psi || !root)
736 return;
737
738 mutex_lock(&psi->read_mutex);
739 if (psi->open && psi->open(psi))
740 goto out;
741
742 /*
743 * Backend callback read() allocates record.buf. decompress_record()
744 * may reallocate record.buf. On success, pstore_mkfile() will keep
745 * the record.buf, so free it only on failure.
746 */
747 for (; stop_loop; stop_loop--) {
748 struct pstore_record *record;
749 int rc;
750
751 record = kzalloc(sizeof(*record), GFP_KERNEL);
752 if (!record) {
753 pr_err("out of memory creating record\n");
754 break;
755 }
756 pstore_record_init(record, psi);
757
758 record->size = psi->read(record);
759
760 /* No more records left in backend? */
761 if (record->size <= 0) {
762 kfree(record);
763 break;
764 }
765
766 decompress_record(record);
767 rc = pstore_mkfile(root, record);
768 if (rc) {
769 /* pstore_mkfile() did not take record, so free it. */
770 kfree(record->buf);
771 kfree(record);
772 if (rc != -EEXIST || !quiet)
773 failed++;
774 }
775 }
776 if (psi->close)
777 psi->close(psi);
778out:
779 mutex_unlock(&psi->read_mutex);
780
781 if (failed)
782 pr_warn("failed to create %d record(s) from '%s'\n",
783 failed, psi->name);
784 if (!stop_loop)
785 pr_err("looping? Too many records seen from '%s'\n",
786 psi->name);
787}
788
789static void pstore_dowork(struct work_struct *work)
790{
791 pstore_get_records(1);
792}
793
794static void pstore_timefunc(struct timer_list *unused)
795{
796 if (pstore_new_entry) {
797 pstore_new_entry = 0;
798 schedule_work(&pstore_work);
799 }
800
801 pstore_timer_kick();
802}
803
804static void __init pstore_choose_compression(void)
805{
806 const struct pstore_zbackend *step;
807
808 if (!compress)
809 return;
810
811 for (step = zbackends; step->name; step++) {
812 if (!strcmp(compress, step->name)) {
813 zbackend = step;
814 return;
815 }
816 }
817}
818
819static int __init pstore_init(void)
820{
821 int ret;
822
823 pstore_choose_compression();
824
825 /*
826 * Check if any pstore backends registered earlier but did not
827 * initialize compression because crypto was not ready. If so,
828 * initialize compression now.
829 */
830 allocate_buf_for_compression();
831
832 ret = pstore_init_fs();
833 if (ret)
834 free_buf_for_compression();
835
836 return ret;
837}
838late_initcall(pstore_init);
839
840static void __exit pstore_exit(void)
841{
842 pstore_exit_fs();
843}
844module_exit(pstore_exit)
845
846MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
847MODULE_LICENSE("GPL");