This source file includes following definitions.
- pstore_set_kmsg_bytes
- pstore_type_to_name
- pstore_name_to_type
- get_reason_str
- pstore_cannot_wait
- zbufsize_deflate
- zbufsize_lzo
- zbufsize_lz4
- zbufsize_842
- zbufsize_zstd
- pstore_compress
- allocate_buf_for_compression
- free_buf_for_compression
- copy_kmsg_to_buffer
- pstore_record_init
- pstore_dump
- pstore_register_kmsg
- pstore_unregister_kmsg
- pstore_console_write
- pstore_register_console
- pstore_unregister_console
- pstore_register_console
- pstore_unregister_console
- pstore_write_user_compat
- pstore_register
- pstore_unregister
- decompress_record
- pstore_get_backend_records
- pstore_dowork
- pstore_timefunc
- pstore_choose_compression
- pstore_init
- pstore_exit
1
2
3
4
5
6
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
40
41
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
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
73
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
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
98 unsigned long kmsg_bytes = PSTORE_DEFAULT_KMSG_BYTES;
99
100 void pstore_set_kmsg_bytes(int bytes)
101 {
102 kmsg_bytes = bytes;
103 }
104
105
106 static int oopscount;
107
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
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
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
154
155
156
157 static bool pstore_cannot_wait(enum kmsg_dump_reason reason)
158 {
159
160 if (in_nmi())
161 return true;
162
163 switch (reason) {
164
165 case KMSG_DUMP_PANIC:
166
167 case KMSG_DUMP_EMERG:
168 return true;
169 default:
170 return false;
171 }
172 }
173
174 #if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
175 static int zbufsize_deflate(size_t size)
176 {
177 size_t cmpr;
178
179 switch (size) {
180
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
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)
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)
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)
218 static int zbufsize_842(size_t size)
219 {
220 return size;
221 }
222 #endif
223
224 #if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
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
273 static 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
287 static void allocate_buf_for_compression(void)
288 {
289 struct crypto_comp *ctx;
290 int size;
291 char *buf;
292
293
294 if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
295 return;
296
297
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
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
336 static 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
349
350
351
352
353
354 static 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
373 void 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
381 record->time = ns_to_timespec64(ktime_get_real_fast_ns());
382 }
383
384
385
386
387
388 static 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
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
436 header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
437 oopscount, part);
438 dst_size -= header_size;
439
440
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
472 static struct kmsg_dumper pstore_dumper = {
473 .dump = pstore_dump,
474 };
475
476
477
478
479 static void pstore_register_kmsg(void)
480 {
481 kmsg_dump_register(&pstore_dumper);
482 }
483
484 static void pstore_unregister_kmsg(void)
485 {
486 kmsg_dump_unregister(&pstore_dumper);
487 }
488
489 #ifdef CONFIG_PSTORE_CONSOLE
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 .name = "pstore",
507 .write = pstore_console_write,
508 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
509 .index = -1,
510 };
511
512 static void pstore_register_console(void)
513 {
514 register_console(&pstore_console);
515 }
516
517 static void pstore_unregister_console(void)
518 {
519 unregister_console(&pstore_console);
520 }
521 #else
522 static void pstore_register_console(void) {}
523 static void pstore_unregister_console(void) {}
524 #endif
525
526 static 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);
543 out:
544 record->buf = NULL;
545
546 return unlikely(ret < 0) ? ret : record->size;
547 }
548
549
550
551
552
553
554
555
556 int 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
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
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
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
623
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 }
633 EXPORT_SYMBOL_GPL(pstore_register);
634
635 void pstore_unregister(struct pstore_info *psi)
636 {
637
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 }
656 EXPORT_SYMBOL_GPL(pstore_unregister);
657
658 static 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
668 if (record->type != PSTORE_TYPE_DMESG) {
669 pr_warn("ignored compressed record type %d\n", record->type);
670 return;
671 }
672
673
674 if (!big_oops_buf) {
675 pr_warn("no decompression method initialized!\n");
676 return;
677 }
678
679
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
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
696 memcpy(workspace + unzipped_len, record->buf + record->size,
697 record->ecc_notice_size);
698
699
700 unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
701 GFP_KERNEL);
702 kfree(workspace);
703 if (!unzipped)
704 return;
705
706
707 kfree(record->buf);
708 record->buf = unzipped;
709 record->size = unzipped_len;
710 record->compressed = false;
711 }
712
713
714
715
716
717
718
719 void 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
734
735
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
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
760 kfree(record->buf);
761 kfree(record);
762 if (rc != -EEXIST || !quiet)
763 failed++;
764 }
765 }
766 if (psi->close)
767 psi->close(psi);
768 out:
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
779 static void pstore_dowork(struct work_struct *work)
780 {
781 pstore_get_records(1);
782 }
783
784 static 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
796 void __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
811 static int __init pstore_init(void)
812 {
813 int ret;
814
815 pstore_choose_compression();
816
817
818
819
820
821
822 allocate_buf_for_compression();
823
824 ret = pstore_init_fs();
825 if (ret)
826 free_buf_for_compression();
827
828 return ret;
829 }
830 late_initcall(pstore_init);
831
832 static void __exit pstore_exit(void)
833 {
834 pstore_exit_fs();
835 }
836 module_exit(pstore_exit)
837
838 module_param(compress, charp, 0444);
839 MODULE_PARM_DESC(compress, "Pstore compression to use");
840
841 module_param(backend, charp, 0444);
842 MODULE_PARM_DESC(backend, "Pstore backend to use");
843
844 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
845 MODULE_LICENSE("GPL");