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