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 */
43 static int pstore_update_ms = -1;
44 module_param_named(update_ms, pstore_update_ms, int, 0600);
45 MODULE_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 */
51 static 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
63 static int pstore_new_entry;
64
65 static void pstore_timefunc(struct timer_list *);
66 static DEFINE_TIMER(pstore_timer, pstore_timefunc);
67
68 static void pstore_dowork(struct work_struct *);
69 static DECLARE_WORK(pstore_work, pstore_dowork);
70
71 /*
72 * pstore_lock just protects "psinfo" during
73 * calls to pstore_register()
74 */
75 static DEFINE_SPINLOCK(pstore_lock);
76 struct pstore_info *psinfo;
77
78 static char *backend;
79 static char *compress =
80 #ifdef CONFIG_PSTORE_COMPRESS_DEFAULT
81 CONFIG_PSTORE_COMPRESS_DEFAULT;
82 #else
83 NULL;
84 #endif
85
86 /* Compression parameters */
87 static struct crypto_comp *tfm;
88
89 struct pstore_zbackend {
90 int (*zbufsize)(size_t size);
91 const char *name;
92 };
93
94 static char *big_oops_buf;
95 static size_t big_oops_buf_sz;
96
97 /* How much of the console log to snapshot */
98 unsigned long kmsg_bytes = PSTORE_DEFAULT_KMSG_BYTES;
99
pstore_set_kmsg_bytes(int bytes)100 void pstore_set_kmsg_bytes(int bytes)
101 {
102 kmsg_bytes = bytes;
103 }
104
105 /* Tag each group of saved records with a sequence number */
106 static int oopscount;
107
pstore_type_to_name(enum pstore_type_id type)108 const 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 }
117 EXPORT_SYMBOL_GPL(pstore_type_to_name);
118
pstore_name_to_type(const char * name)119 enum 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 }
130 EXPORT_SYMBOL_GPL(pstore_name_to_type);
131
get_reason_str(enum kmsg_dump_reason reason)132 static 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 */
pstore_cannot_wait(enum kmsg_dump_reason reason)157 static 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)
zbufsize_deflate(size_t size)175 static 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)
zbufsize_lzo(size_t size)204 static 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)
zbufsize_lz4(size_t size)211 static int zbufsize_lz4(size_t size)
212 {
213 return LZ4_compressBound(size);
214 }
215 #endif
216
217 #if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
zbufsize_842(size_t size)218 static int zbufsize_842(size_t size)
219 {
220 return size;
221 }
222 #endif
223
224 #if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
zbufsize_zstd(size_t size)225 static int zbufsize_zstd(size_t size)
226 {
227 return ZSTD_compressBound(size);
228 }
229 #endif
230
231 static const struct pstore_zbackend *zbackend __ro_after_init;
232
233 static 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
pstore_compress(const void * in,void * out,unsigned int inlen,unsigned int outlen)273 static int pstore_compress(const void *in, void *out,
274 unsigned int inlen, unsigned int outlen)
275 {
276 int ret;
277
278 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS))
279 return -EINVAL;
280
281 ret = crypto_comp_compress(tfm, in, inlen, out, &outlen);
282 if (ret) {
283 pr_err("crypto_comp_compress failed, ret = %d!\n", ret);
284 return ret;
285 }
286
287 return outlen;
288 }
289
allocate_buf_for_compression(void)290 static void allocate_buf_for_compression(void)
291 {
292 struct crypto_comp *ctx;
293 int size;
294 char *buf;
295
296 /* Skip if not built-in or compression backend not selected yet. */
297 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
298 return;
299
300 /* Skip if no pstore backend yet or compression init already done. */
301 if (!psinfo || tfm)
302 return;
303
304 if (!crypto_has_comp(zbackend->name, 0, 0)) {
305 pr_err("Unknown compression: %s\n", zbackend->name);
306 return;
307 }
308
309 size = zbackend->zbufsize(psinfo->bufsize);
310 if (size <= 0) {
311 pr_err("Invalid compression size for %s: %d\n",
312 zbackend->name, size);
313 return;
314 }
315
316 buf = kmalloc(size, GFP_KERNEL);
317 if (!buf) {
318 pr_err("Failed %d byte compression buffer allocation for: %s\n",
319 size, zbackend->name);
320 return;
321 }
322
323 ctx = crypto_alloc_comp(zbackend->name, 0, 0);
324 if (IS_ERR_OR_NULL(ctx)) {
325 kfree(buf);
326 pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
327 PTR_ERR(ctx));
328 return;
329 }
330
331 /* A non-NULL big_oops_buf indicates compression is available. */
332 tfm = ctx;
333 big_oops_buf_sz = size;
334 big_oops_buf = buf;
335
336 pr_info("Using crash dump compression: %s\n", zbackend->name);
337 }
338
free_buf_for_compression(void)339 static void free_buf_for_compression(void)
340 {
341 if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) {
342 crypto_free_comp(tfm);
343 tfm = NULL;
344 }
345 kfree(big_oops_buf);
346 big_oops_buf = NULL;
347 big_oops_buf_sz = 0;
348 }
349
350 /*
351 * Called when compression fails, since the printk buffer
352 * would be fetched for compression calling it again when
353 * compression fails would have moved the iterator of
354 * printk buffer which results in fetching old contents.
355 * Copy the recent messages from big_oops_buf to psinfo->buf
356 */
copy_kmsg_to_buffer(int hsize,size_t len)357 static size_t copy_kmsg_to_buffer(int hsize, size_t len)
358 {
359 size_t total_len;
360 size_t diff;
361
362 total_len = hsize + len;
363
364 if (total_len > psinfo->bufsize) {
365 diff = total_len - psinfo->bufsize + hsize;
366 memcpy(psinfo->buf, big_oops_buf, hsize);
367 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
368 psinfo->bufsize - hsize);
369 total_len = psinfo->bufsize;
370 } else
371 memcpy(psinfo->buf, big_oops_buf, total_len);
372
373 return total_len;
374 }
375
pstore_record_init(struct pstore_record * record,struct pstore_info * psinfo)376 void pstore_record_init(struct pstore_record *record,
377 struct pstore_info *psinfo)
378 {
379 memset(record, 0, sizeof(*record));
380
381 record->psi = psinfo;
382
383 /* Report zeroed timestamp if called before timekeeping has resumed. */
384 record->time = ns_to_timespec64(ktime_get_real_fast_ns());
385 }
386
387 /*
388 * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
389 * end of the buffer.
390 */
pstore_dump(struct kmsg_dumper * dumper,enum kmsg_dump_reason reason)391 static void pstore_dump(struct kmsg_dumper *dumper,
392 enum kmsg_dump_reason reason)
393 {
394 unsigned long total = 0;
395 const char *why;
396 unsigned int part = 1;
397 int ret;
398
399 why = get_reason_str(reason);
400
401 if (down_trylock(&psinfo->buf_lock)) {
402 /* Failed to acquire lock: give up if we cannot wait. */
403 if (pstore_cannot_wait(reason)) {
404 pr_err("dump skipped in %s path: may corrupt error record\n",
405 in_nmi() ? "NMI" : why);
406 return;
407 }
408 if (down_interruptible(&psinfo->buf_lock)) {
409 pr_err("could not grab semaphore?!\n");
410 return;
411 }
412 }
413
414 oopscount++;
415 while (total < kmsg_bytes) {
416 char *dst;
417 size_t dst_size;
418 int header_size;
419 int zipped_len = -1;
420 size_t dump_size;
421 struct pstore_record record;
422
423 pstore_record_init(&record, psinfo);
424 record.type = PSTORE_TYPE_DMESG;
425 record.count = oopscount;
426 record.reason = reason;
427 record.part = part;
428 record.buf = psinfo->buf;
429
430 if (big_oops_buf) {
431 dst = big_oops_buf;
432 dst_size = big_oops_buf_sz;
433 } else {
434 dst = psinfo->buf;
435 dst_size = psinfo->bufsize;
436 }
437
438 /* Write dump header. */
439 header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
440 oopscount, part);
441 dst_size -= header_size;
442
443 /* Write dump contents. */
444 if (!kmsg_dump_get_buffer(dumper, true, dst + header_size,
445 dst_size, &dump_size))
446 break;
447
448 if (big_oops_buf) {
449 zipped_len = pstore_compress(dst, psinfo->buf,
450 header_size + dump_size,
451 psinfo->bufsize);
452
453 if (zipped_len > 0) {
454 record.compressed = true;
455 record.size = zipped_len;
456 } else {
457 record.size = copy_kmsg_to_buffer(header_size,
458 dump_size);
459 }
460 } else {
461 record.size = header_size + dump_size;
462 }
463
464 ret = psinfo->write(&record);
465 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
466 pstore_new_entry = 1;
467
468 total += record.size;
469 part++;
470 }
471
472 up(&psinfo->buf_lock);
473 }
474
475 static struct kmsg_dumper pstore_dumper = {
476 .dump = pstore_dump,
477 };
478
479 /*
480 * Register with kmsg_dump to save last part of console log on panic.
481 */
pstore_register_kmsg(void)482 static void pstore_register_kmsg(void)
483 {
484 kmsg_dump_register(&pstore_dumper);
485 }
486
pstore_unregister_kmsg(void)487 static void pstore_unregister_kmsg(void)
488 {
489 kmsg_dump_unregister(&pstore_dumper);
490 }
491
492 #ifdef CONFIG_PSTORE_CONSOLE
pstore_console_write(struct console * con,const char * s,unsigned c)493 static void pstore_console_write(struct console *con, const char *s, unsigned c)
494 {
495 struct pstore_record record;
496
497 if (!c)
498 return;
499
500 pstore_record_init(&record, psinfo);
501 record.type = PSTORE_TYPE_CONSOLE;
502
503 record.buf = (char *)s;
504 record.size = c;
505 psinfo->write(&record);
506 }
507
508 static struct console pstore_console = {
509 .name = "pstore",
510 .write = pstore_console_write,
511 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
512 .index = -1,
513 };
514
pstore_register_console(void)515 static void pstore_register_console(void)
516 {
517 register_console(&pstore_console);
518 }
519
pstore_unregister_console(void)520 static void pstore_unregister_console(void)
521 {
522 unregister_console(&pstore_console);
523 }
524 #else
pstore_register_console(void)525 static void pstore_register_console(void) {}
pstore_unregister_console(void)526 static void pstore_unregister_console(void) {}
527 #endif
528
pstore_write_user_compat(struct pstore_record * record,const char __user * buf)529 static int pstore_write_user_compat(struct pstore_record *record,
530 const char __user *buf)
531 {
532 int ret = 0;
533
534 if (record->buf)
535 return -EINVAL;
536
537 record->buf = memdup_user(buf, record->size);
538 if (IS_ERR(record->buf)) {
539 ret = PTR_ERR(record->buf);
540 goto out;
541 }
542
543 ret = record->psi->write(record);
544
545 kfree(record->buf);
546 out:
547 record->buf = NULL;
548
549 return unlikely(ret < 0) ? ret : record->size;
550 }
551
552 /*
553 * platform specific persistent storage driver registers with
554 * us here. If pstore is already mounted, call the platform
555 * read function right away to populate the file system. If not
556 * then the pstore mount code will call us later to fill out
557 * the file system.
558 */
pstore_register(struct pstore_info * psi)559 int pstore_register(struct pstore_info *psi)
560 {
561 struct module *owner = psi->owner;
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 spin_lock(&pstore_lock);
583 if (psinfo) {
584 pr_warn("backend '%s' already loaded: ignoring '%s'\n",
585 psinfo->name, psi->name);
586 spin_unlock(&pstore_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 spin_unlock(&pstore_lock);
596
597 if (owner && !try_module_get(owner)) {
598 psinfo = NULL;
599 return -EINVAL;
600 }
601
602 if (psi->flags & PSTORE_FLAGS_DMESG)
603 allocate_buf_for_compression();
604
605 if (pstore_is_mounted())
606 pstore_get_records(0);
607
608 if (psi->flags & PSTORE_FLAGS_DMESG)
609 pstore_register_kmsg();
610 if (psi->flags & PSTORE_FLAGS_CONSOLE)
611 pstore_register_console();
612 if (psi->flags & PSTORE_FLAGS_FTRACE)
613 pstore_register_ftrace();
614 if (psi->flags & PSTORE_FLAGS_PMSG)
615 pstore_register_pmsg();
616
617 /* Start watching for new records, if desired. */
618 if (pstore_update_ms >= 0) {
619 pstore_timer.expires = jiffies +
620 msecs_to_jiffies(pstore_update_ms);
621 add_timer(&pstore_timer);
622 }
623
624 /*
625 * Update the module parameter backend, so it is visible
626 * through /sys/module/pstore/parameters/backend
627 */
628 backend = psi->name;
629
630 pr_info("Registered %s as persistent store backend\n", psi->name);
631
632 module_put(owner);
633
634 return 0;
635 }
636 EXPORT_SYMBOL_GPL(pstore_register);
637
pstore_unregister(struct pstore_info * psi)638 void pstore_unregister(struct pstore_info *psi)
639 {
640 /* Stop timer and make sure all work has finished. */
641 pstore_update_ms = -1;
642 del_timer_sync(&pstore_timer);
643 flush_work(&pstore_work);
644
645 if (psi->flags & PSTORE_FLAGS_PMSG)
646 pstore_unregister_pmsg();
647 if (psi->flags & PSTORE_FLAGS_FTRACE)
648 pstore_unregister_ftrace();
649 if (psi->flags & PSTORE_FLAGS_CONSOLE)
650 pstore_unregister_console();
651 if (psi->flags & PSTORE_FLAGS_DMESG)
652 pstore_unregister_kmsg();
653
654 free_buf_for_compression();
655
656 psinfo = NULL;
657 backend = NULL;
658 }
659 EXPORT_SYMBOL_GPL(pstore_unregister);
660
decompress_record(struct pstore_record * record)661 static void decompress_record(struct pstore_record *record)
662 {
663 int ret;
664 int unzipped_len;
665 char *unzipped, *workspace;
666
667 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
668 return;
669
670 /* Only PSTORE_TYPE_DMESG support compression. */
671 if (record->type != PSTORE_TYPE_DMESG) {
672 pr_warn("ignored compressed record type %d\n", record->type);
673 return;
674 }
675
676 /* Missing compression buffer means compression was not initialized. */
677 if (!big_oops_buf) {
678 pr_warn("no decompression method initialized!\n");
679 return;
680 }
681
682 /* Allocate enough space to hold max decompression and ECC. */
683 unzipped_len = big_oops_buf_sz;
684 workspace = kmalloc(unzipped_len + record->ecc_notice_size,
685 GFP_KERNEL);
686 if (!workspace)
687 return;
688
689 /* After decompression "unzipped_len" is almost certainly smaller. */
690 ret = crypto_comp_decompress(tfm, record->buf, record->size,
691 workspace, &unzipped_len);
692 if (ret) {
693 pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
694 kfree(workspace);
695 return;
696 }
697
698 /* Append ECC notice to decompressed buffer. */
699 memcpy(workspace + unzipped_len, record->buf + record->size,
700 record->ecc_notice_size);
701
702 /* Copy decompressed contents into an minimum-sized allocation. */
703 unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
704 GFP_KERNEL);
705 kfree(workspace);
706 if (!unzipped)
707 return;
708
709 /* Swap out compressed contents with decompressed contents. */
710 kfree(record->buf);
711 record->buf = unzipped;
712 record->size = unzipped_len;
713 record->compressed = false;
714 }
715
716 /*
717 * Read all the records from one persistent store backend. Create
718 * files in our filesystem. Don't warn about -EEXIST errors
719 * when we are re-scanning the backing store looking to add new
720 * error records.
721 */
pstore_get_backend_records(struct pstore_info * psi,struct dentry * root,int quiet)722 void pstore_get_backend_records(struct pstore_info *psi,
723 struct dentry *root, int quiet)
724 {
725 int failed = 0;
726 unsigned int stop_loop = 65536;
727
728 if (!psi || !root)
729 return;
730
731 mutex_lock(&psi->read_mutex);
732 if (psi->open && psi->open(psi))
733 goto out;
734
735 /*
736 * Backend callback read() allocates record.buf. decompress_record()
737 * may reallocate record.buf. On success, pstore_mkfile() will keep
738 * the record.buf, so free it only on failure.
739 */
740 for (; stop_loop; stop_loop--) {
741 struct pstore_record *record;
742 int rc;
743
744 record = kzalloc(sizeof(*record), GFP_KERNEL);
745 if (!record) {
746 pr_err("out of memory creating record\n");
747 break;
748 }
749 pstore_record_init(record, psi);
750
751 record->size = psi->read(record);
752
753 /* No more records left in backend? */
754 if (record->size <= 0) {
755 kfree(record);
756 break;
757 }
758
759 decompress_record(record);
760 rc = pstore_mkfile(root, record);
761 if (rc) {
762 /* pstore_mkfile() did not take record, so free it. */
763 kfree(record->buf);
764 kfree(record);
765 if (rc != -EEXIST || !quiet)
766 failed++;
767 }
768 }
769 if (psi->close)
770 psi->close(psi);
771 out:
772 mutex_unlock(&psi->read_mutex);
773
774 if (failed)
775 pr_warn("failed to create %d record(s) from '%s'\n",
776 failed, psi->name);
777 if (!stop_loop)
778 pr_err("looping? Too many records seen from '%s'\n",
779 psi->name);
780 }
781
pstore_dowork(struct work_struct * work)782 static void pstore_dowork(struct work_struct *work)
783 {
784 pstore_get_records(1);
785 }
786
pstore_timefunc(struct timer_list * unused)787 static void pstore_timefunc(struct timer_list *unused)
788 {
789 if (pstore_new_entry) {
790 pstore_new_entry = 0;
791 schedule_work(&pstore_work);
792 }
793
794 if (pstore_update_ms >= 0)
795 mod_timer(&pstore_timer,
796 jiffies + msecs_to_jiffies(pstore_update_ms));
797 }
798
pstore_choose_compression(void)799 void __init pstore_choose_compression(void)
800 {
801 const struct pstore_zbackend *step;
802
803 if (!compress)
804 return;
805
806 for (step = zbackends; step->name; step++) {
807 if (!strcmp(compress, step->name)) {
808 zbackend = step;
809 return;
810 }
811 }
812 }
813
pstore_init(void)814 static int __init pstore_init(void)
815 {
816 int ret;
817
818 pstore_choose_compression();
819
820 /*
821 * Check if any pstore backends registered earlier but did not
822 * initialize compression because crypto was not ready. If so,
823 * initialize compression now.
824 */
825 allocate_buf_for_compression();
826
827 ret = pstore_init_fs();
828 if (ret)
829 free_buf_for_compression();
830
831 return ret;
832 }
833 late_initcall(pstore_init);
834
pstore_exit(void)835 static void __exit pstore_exit(void)
836 {
837 pstore_exit_fs();
838 }
839 module_exit(pstore_exit)
840
841 module_param(compress, charp, 0444);
842 MODULE_PARM_DESC(compress, "Pstore compression to use");
843
844 module_param(backend, charp, 0444);
845 MODULE_PARM_DESC(backend, "Pstore backend to use");
846
847 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
848 MODULE_LICENSE("GPL");
849