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/mm.h> |
18 | #include <linux/module.h> |
19 | #include <linux/pstore.h> |
20 | #include <linux/string.h> |
21 | #include <linux/timer.h> |
22 | #include <linux/slab.h> |
23 | #include <linux/uaccess.h> |
24 | #include <linux/jiffies.h> |
25 | #include <linux/vmalloc.h> |
26 | #include <linux/workqueue.h> |
27 | #include <linux/zlib.h> |
28 | |
29 | #include "internal.h" |
30 | |
31 | /* |
32 | * We defer making "oops" entries appear in pstore - see |
33 | * whether the system is actually still running well enough |
34 | * to let someone see the entry |
35 | */ |
36 | static int pstore_update_ms = -1; |
37 | module_param_named(update_ms, pstore_update_ms, int, 0600); |
38 | MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content " |
39 | "(default is -1, which means runtime updates are disabled; " |
40 | "enabling this option may not be safe; it may lead to further " |
41 | "corruption on Oopses)" ); |
42 | |
43 | /* Names should be in the same order as the enum pstore_type_id */ |
44 | static const char * const pstore_type_names[] = { |
45 | "dmesg" , |
46 | "mce" , |
47 | "console" , |
48 | "ftrace" , |
49 | "rtas" , |
50 | "powerpc-ofw" , |
51 | "powerpc-common" , |
52 | "pmsg" , |
53 | "powerpc-opal" , |
54 | }; |
55 | |
56 | static int pstore_new_entry; |
57 | |
58 | static void pstore_timefunc(struct timer_list *); |
59 | static DEFINE_TIMER(pstore_timer, pstore_timefunc); |
60 | |
61 | static void pstore_dowork(struct work_struct *); |
62 | static DECLARE_WORK(pstore_work, pstore_dowork); |
63 | |
64 | /* |
65 | * psinfo_lock protects "psinfo" during calls to |
66 | * pstore_register(), pstore_unregister(), and |
67 | * the filesystem mount/unmount routines. |
68 | */ |
69 | static DEFINE_MUTEX(psinfo_lock); |
70 | struct pstore_info *psinfo; |
71 | |
72 | static char *backend; |
73 | module_param(backend, charp, 0444); |
74 | MODULE_PARM_DESC(backend, "specific backend to use" ); |
75 | |
76 | /* |
77 | * pstore no longer implements compression via the crypto API, and only |
78 | * supports zlib deflate compression implemented using the zlib library |
79 | * interface. This removes additional complexity which is hard to justify for a |
80 | * diagnostic facility that has to operate in conditions where the system may |
81 | * have become unstable. Zlib deflate is comparatively small in terms of code |
82 | * size, and compresses ASCII text comparatively well. In terms of compression |
83 | * speed, deflate is not the best performer but for recording the log output on |
84 | * a kernel panic, this is not considered critical. |
85 | * |
86 | * The only remaining arguments supported by the compress= module parameter are |
87 | * 'deflate' and 'none'. To retain compatibility with existing installations, |
88 | * all other values are logged and replaced with 'deflate'. |
89 | */ |
90 | static char *compress = "deflate" ; |
91 | module_param(compress, charp, 0444); |
92 | MODULE_PARM_DESC(compress, "compression to use" ); |
93 | |
94 | /* How much of the kernel log to snapshot */ |
95 | unsigned long kmsg_bytes = CONFIG_PSTORE_DEFAULT_KMSG_BYTES; |
96 | module_param(kmsg_bytes, ulong, 0444); |
97 | MODULE_PARM_DESC(kmsg_bytes, "amount of kernel log to snapshot (in bytes)" ); |
98 | |
99 | static void *compress_workspace; |
100 | |
101 | /* |
102 | * Compression is only used for dmesg output, which consists of low-entropy |
103 | * ASCII text, and so we can assume worst-case 60%. |
104 | */ |
105 | #define DMESG_COMP_PERCENT 60 |
106 | |
107 | static char *big_oops_buf; |
108 | static size_t max_compressed_size; |
109 | |
110 | void pstore_set_kmsg_bytes(int bytes) |
111 | { |
112 | kmsg_bytes = bytes; |
113 | } |
114 | |
115 | /* Tag each group of saved records with a sequence number */ |
116 | static int oopscount; |
117 | |
118 | const char *pstore_type_to_name(enum pstore_type_id type) |
119 | { |
120 | BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX); |
121 | |
122 | if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX)) |
123 | return "unknown" ; |
124 | |
125 | return pstore_type_names[type]; |
126 | } |
127 | EXPORT_SYMBOL_GPL(pstore_type_to_name); |
128 | |
129 | enum pstore_type_id pstore_name_to_type(const char *name) |
130 | { |
131 | int i; |
132 | |
133 | for (i = 0; i < PSTORE_TYPE_MAX; i++) { |
134 | if (!strcmp(pstore_type_names[i], name)) |
135 | return i; |
136 | } |
137 | |
138 | return PSTORE_TYPE_MAX; |
139 | } |
140 | EXPORT_SYMBOL_GPL(pstore_name_to_type); |
141 | |
142 | static void pstore_timer_kick(void) |
143 | { |
144 | if (pstore_update_ms < 0) |
145 | return; |
146 | |
147 | mod_timer(timer: &pstore_timer, expires: jiffies + msecs_to_jiffies(m: pstore_update_ms)); |
148 | } |
149 | |
150 | static bool pstore_cannot_block_path(enum kmsg_dump_reason reason) |
151 | { |
152 | /* |
153 | * In case of NMI path, pstore shouldn't be blocked |
154 | * regardless of reason. |
155 | */ |
156 | if (in_nmi()) |
157 | return true; |
158 | |
159 | switch (reason) { |
160 | /* In panic case, other cpus are stopped by smp_send_stop(). */ |
161 | case KMSG_DUMP_PANIC: |
162 | /* |
163 | * Emergency restart shouldn't be blocked by spinning on |
164 | * pstore_info::buf_lock. |
165 | */ |
166 | case KMSG_DUMP_EMERG: |
167 | return true; |
168 | default: |
169 | return false; |
170 | } |
171 | } |
172 | |
173 | static int pstore_compress(const void *in, void *out, |
174 | unsigned int inlen, unsigned int outlen) |
175 | { |
176 | struct z_stream_s zstream = { |
177 | .next_in = in, |
178 | .avail_in = inlen, |
179 | .next_out = out, |
180 | .avail_out = outlen, |
181 | .workspace = compress_workspace, |
182 | }; |
183 | int ret; |
184 | |
185 | if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS)) |
186 | return -EINVAL; |
187 | |
188 | ret = zlib_deflateInit2(strm: &zstream, Z_DEFAULT_COMPRESSION, Z_DEFLATED, |
189 | windowBits: -MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY); |
190 | if (ret != Z_OK) |
191 | return -EINVAL; |
192 | |
193 | ret = zlib_deflate(strm: &zstream, Z_FINISH); |
194 | if (ret != Z_STREAM_END) |
195 | return -EINVAL; |
196 | |
197 | ret = zlib_deflateEnd(strm: &zstream); |
198 | if (ret != Z_OK) |
199 | pr_warn_once("zlib_deflateEnd() failed: %d\n" , ret); |
200 | |
201 | return zstream.total_out; |
202 | } |
203 | |
204 | static void allocate_buf_for_compression(void) |
205 | { |
206 | size_t compressed_size; |
207 | char *buf; |
208 | |
209 | /* Skip if not built-in or compression disabled. */ |
210 | if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !compress || |
211 | !strcmp(compress, "none" )) { |
212 | compress = NULL; |
213 | return; |
214 | } |
215 | |
216 | if (strcmp(compress, "deflate" )) { |
217 | pr_err("Unsupported compression '%s', falling back to deflate\n" , |
218 | compress); |
219 | compress = "deflate" ; |
220 | } |
221 | |
222 | /* |
223 | * The compression buffer only needs to be as large as the maximum |
224 | * uncompressed record size, since any record that would be expanded by |
225 | * compression is just stored uncompressed. |
226 | */ |
227 | compressed_size = (psinfo->bufsize * 100) / DMESG_COMP_PERCENT; |
228 | buf = kvzalloc(size: compressed_size, GFP_KERNEL); |
229 | if (!buf) { |
230 | pr_err("Failed %zu byte compression buffer allocation for: %s\n" , |
231 | psinfo->bufsize, compress); |
232 | return; |
233 | } |
234 | |
235 | compress_workspace = |
236 | vmalloc(size: zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL)); |
237 | if (!compress_workspace) { |
238 | pr_err("Failed to allocate zlib deflate workspace\n" ); |
239 | kvfree(addr: buf); |
240 | return; |
241 | } |
242 | |
243 | /* A non-NULL big_oops_buf indicates compression is available. */ |
244 | big_oops_buf = buf; |
245 | max_compressed_size = compressed_size; |
246 | |
247 | pr_info("Using crash dump compression: %s\n" , compress); |
248 | } |
249 | |
250 | static void free_buf_for_compression(void) |
251 | { |
252 | if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress_workspace) { |
253 | vfree(addr: compress_workspace); |
254 | compress_workspace = NULL; |
255 | } |
256 | |
257 | kvfree(addr: big_oops_buf); |
258 | big_oops_buf = NULL; |
259 | max_compressed_size = 0; |
260 | } |
261 | |
262 | void pstore_record_init(struct pstore_record *record, |
263 | struct pstore_info *psinfo) |
264 | { |
265 | memset(record, 0, sizeof(*record)); |
266 | |
267 | record->psi = psinfo; |
268 | |
269 | /* Report zeroed timestamp if called before timekeeping has resumed. */ |
270 | record->time = ns_to_timespec64(nsec: ktime_get_real_fast_ns()); |
271 | } |
272 | |
273 | /* |
274 | * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the |
275 | * end of the buffer. |
276 | */ |
277 | static void pstore_dump(struct kmsg_dumper *dumper, |
278 | enum kmsg_dump_reason reason) |
279 | { |
280 | struct kmsg_dump_iter iter; |
281 | unsigned long total = 0; |
282 | const char *why; |
283 | unsigned int part = 1; |
284 | unsigned long flags = 0; |
285 | int saved_ret = 0; |
286 | int ret; |
287 | |
288 | why = kmsg_dump_reason_str(reason); |
289 | |
290 | if (pstore_cannot_block_path(reason)) { |
291 | if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) { |
292 | pr_err("dump skipped in %s path because of concurrent dump\n" , |
293 | in_nmi() ? "NMI" : why); |
294 | return; |
295 | } |
296 | } else { |
297 | spin_lock_irqsave(&psinfo->buf_lock, flags); |
298 | } |
299 | |
300 | kmsg_dump_rewind(iter: &iter); |
301 | |
302 | oopscount++; |
303 | while (total < kmsg_bytes) { |
304 | char *dst; |
305 | size_t dst_size; |
306 | int ; |
307 | int zipped_len = -1; |
308 | size_t dump_size; |
309 | struct pstore_record record; |
310 | |
311 | pstore_record_init(record: &record, psinfo); |
312 | record.type = PSTORE_TYPE_DMESG; |
313 | record.count = oopscount; |
314 | record.reason = reason; |
315 | record.part = part; |
316 | record.buf = psinfo->buf; |
317 | |
318 | dst = big_oops_buf ?: psinfo->buf; |
319 | dst_size = max_compressed_size ?: psinfo->bufsize; |
320 | |
321 | /* Write dump header. */ |
322 | header_size = snprintf(buf: dst, size: dst_size, fmt: "%s#%d Part%u\n" , why, |
323 | oopscount, part); |
324 | dst_size -= header_size; |
325 | |
326 | /* Write dump contents. */ |
327 | if (!kmsg_dump_get_buffer(iter: &iter, syslog: true, buf: dst + header_size, |
328 | size: dst_size, len_out: &dump_size)) |
329 | break; |
330 | |
331 | if (big_oops_buf) { |
332 | zipped_len = pstore_compress(in: dst, out: psinfo->buf, |
333 | inlen: header_size + dump_size, |
334 | outlen: psinfo->bufsize); |
335 | |
336 | if (zipped_len > 0) { |
337 | record.compressed = true; |
338 | record.size = zipped_len; |
339 | } else { |
340 | /* |
341 | * Compression failed, so the buffer is most |
342 | * likely filled with binary data that does not |
343 | * compress as well as ASCII text. Copy as much |
344 | * of the uncompressed data as possible into |
345 | * the pstore record, and discard the rest. |
346 | */ |
347 | record.size = psinfo->bufsize; |
348 | memcpy(psinfo->buf, dst, psinfo->bufsize); |
349 | } |
350 | } else { |
351 | record.size = header_size + dump_size; |
352 | } |
353 | |
354 | ret = psinfo->write(&record); |
355 | if (ret == 0 && reason == KMSG_DUMP_OOPS) { |
356 | pstore_new_entry = 1; |
357 | pstore_timer_kick(); |
358 | } else { |
359 | /* Preserve only the first non-zero returned value. */ |
360 | if (!saved_ret) |
361 | saved_ret = ret; |
362 | } |
363 | |
364 | total += record.size; |
365 | part++; |
366 | } |
367 | spin_unlock_irqrestore(lock: &psinfo->buf_lock, flags); |
368 | |
369 | if (saved_ret) { |
370 | pr_err_once("backend (%s) writing error (%d)\n" , psinfo->name, |
371 | saved_ret); |
372 | } |
373 | } |
374 | |
375 | static struct kmsg_dumper pstore_dumper = { |
376 | .dump = pstore_dump, |
377 | }; |
378 | |
379 | /* |
380 | * Register with kmsg_dump to save last part of console log on panic. |
381 | */ |
382 | static void pstore_register_kmsg(void) |
383 | { |
384 | kmsg_dump_register(dumper: &pstore_dumper); |
385 | } |
386 | |
387 | static void pstore_unregister_kmsg(void) |
388 | { |
389 | kmsg_dump_unregister(dumper: &pstore_dumper); |
390 | } |
391 | |
392 | #ifdef CONFIG_PSTORE_CONSOLE |
393 | static void pstore_console_write(struct console *con, const char *s, unsigned c) |
394 | { |
395 | struct pstore_record record; |
396 | |
397 | if (!c) |
398 | return; |
399 | |
400 | pstore_record_init(record: &record, psinfo); |
401 | record.type = PSTORE_TYPE_CONSOLE; |
402 | |
403 | record.buf = (char *)s; |
404 | record.size = c; |
405 | psinfo->write(&record); |
406 | } |
407 | |
408 | static struct console pstore_console = { |
409 | .write = pstore_console_write, |
410 | .index = -1, |
411 | }; |
412 | |
413 | static void pstore_register_console(void) |
414 | { |
415 | /* Show which backend is going to get console writes. */ |
416 | strscpy(pstore_console.name, psinfo->name, |
417 | sizeof(pstore_console.name)); |
418 | /* |
419 | * Always initialize flags here since prior unregister_console() |
420 | * calls may have changed settings (specifically CON_ENABLED). |
421 | */ |
422 | pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME; |
423 | register_console(&pstore_console); |
424 | } |
425 | |
426 | static void pstore_unregister_console(void) |
427 | { |
428 | unregister_console(&pstore_console); |
429 | } |
430 | #else |
431 | static void pstore_register_console(void) {} |
432 | static void pstore_unregister_console(void) {} |
433 | #endif |
434 | |
435 | static int pstore_write_user_compat(struct pstore_record *record, |
436 | const char __user *buf) |
437 | { |
438 | int ret = 0; |
439 | |
440 | if (record->buf) |
441 | return -EINVAL; |
442 | |
443 | record->buf = vmemdup_user(buf, record->size); |
444 | if (IS_ERR(ptr: record->buf)) { |
445 | ret = PTR_ERR(ptr: record->buf); |
446 | goto out; |
447 | } |
448 | |
449 | ret = record->psi->write(record); |
450 | |
451 | kvfree(addr: record->buf); |
452 | out: |
453 | record->buf = NULL; |
454 | |
455 | return unlikely(ret < 0) ? ret : record->size; |
456 | } |
457 | |
458 | /* |
459 | * platform specific persistent storage driver registers with |
460 | * us here. If pstore is already mounted, call the platform |
461 | * read function right away to populate the file system. If not |
462 | * then the pstore mount code will call us later to fill out |
463 | * the file system. |
464 | */ |
465 | int pstore_register(struct pstore_info *psi) |
466 | { |
467 | char *new_backend; |
468 | |
469 | if (backend && strcmp(backend, psi->name)) { |
470 | pr_warn("backend '%s' already in use: ignoring '%s'\n" , |
471 | backend, psi->name); |
472 | return -EBUSY; |
473 | } |
474 | |
475 | /* Sanity check flags. */ |
476 | if (!psi->flags) { |
477 | pr_warn("backend '%s' must support at least one frontend\n" , |
478 | psi->name); |
479 | return -EINVAL; |
480 | } |
481 | |
482 | /* Check for required functions. */ |
483 | if (!psi->read || !psi->write) { |
484 | pr_warn("backend '%s' must implement read() and write()\n" , |
485 | psi->name); |
486 | return -EINVAL; |
487 | } |
488 | |
489 | new_backend = kstrdup(s: psi->name, GFP_KERNEL); |
490 | if (!new_backend) |
491 | return -ENOMEM; |
492 | |
493 | mutex_lock(&psinfo_lock); |
494 | if (psinfo) { |
495 | pr_warn("backend '%s' already loaded: ignoring '%s'\n" , |
496 | psinfo->name, psi->name); |
497 | mutex_unlock(lock: &psinfo_lock); |
498 | kfree(objp: new_backend); |
499 | return -EBUSY; |
500 | } |
501 | |
502 | if (!psi->write_user) |
503 | psi->write_user = pstore_write_user_compat; |
504 | psinfo = psi; |
505 | mutex_init(&psinfo->read_mutex); |
506 | spin_lock_init(&psinfo->buf_lock); |
507 | |
508 | if (psi->flags & PSTORE_FLAGS_DMESG) |
509 | allocate_buf_for_compression(); |
510 | |
511 | pstore_get_records(0); |
512 | |
513 | if (psi->flags & PSTORE_FLAGS_DMESG) { |
514 | pstore_dumper.max_reason = psinfo->max_reason; |
515 | pstore_register_kmsg(); |
516 | } |
517 | if (psi->flags & PSTORE_FLAGS_CONSOLE) |
518 | pstore_register_console(); |
519 | if (psi->flags & PSTORE_FLAGS_FTRACE) |
520 | pstore_register_ftrace(); |
521 | if (psi->flags & PSTORE_FLAGS_PMSG) |
522 | pstore_register_pmsg(); |
523 | |
524 | /* Start watching for new records, if desired. */ |
525 | pstore_timer_kick(); |
526 | |
527 | /* |
528 | * Update the module parameter backend, so it is visible |
529 | * through /sys/module/pstore/parameters/backend |
530 | */ |
531 | backend = new_backend; |
532 | |
533 | pr_info("Registered %s as persistent store backend\n" , psi->name); |
534 | |
535 | mutex_unlock(lock: &psinfo_lock); |
536 | return 0; |
537 | } |
538 | EXPORT_SYMBOL_GPL(pstore_register); |
539 | |
540 | void pstore_unregister(struct pstore_info *psi) |
541 | { |
542 | /* It's okay to unregister nothing. */ |
543 | if (!psi) |
544 | return; |
545 | |
546 | mutex_lock(&psinfo_lock); |
547 | |
548 | /* Only one backend can be registered at a time. */ |
549 | if (WARN_ON(psi != psinfo)) { |
550 | mutex_unlock(lock: &psinfo_lock); |
551 | return; |
552 | } |
553 | |
554 | /* Unregister all callbacks. */ |
555 | if (psi->flags & PSTORE_FLAGS_PMSG) |
556 | pstore_unregister_pmsg(); |
557 | if (psi->flags & PSTORE_FLAGS_FTRACE) |
558 | pstore_unregister_ftrace(); |
559 | if (psi->flags & PSTORE_FLAGS_CONSOLE) |
560 | pstore_unregister_console(); |
561 | if (psi->flags & PSTORE_FLAGS_DMESG) |
562 | pstore_unregister_kmsg(); |
563 | |
564 | /* Stop timer and make sure all work has finished. */ |
565 | del_timer_sync(timer: &pstore_timer); |
566 | flush_work(work: &pstore_work); |
567 | |
568 | /* Remove all backend records from filesystem tree. */ |
569 | pstore_put_backend_records(psi); |
570 | |
571 | free_buf_for_compression(); |
572 | |
573 | psinfo = NULL; |
574 | kfree(objp: backend); |
575 | backend = NULL; |
576 | |
577 | pr_info("Unregistered %s as persistent store backend\n" , psi->name); |
578 | mutex_unlock(lock: &psinfo_lock); |
579 | } |
580 | EXPORT_SYMBOL_GPL(pstore_unregister); |
581 | |
582 | static void decompress_record(struct pstore_record *record, |
583 | struct z_stream_s *zstream) |
584 | { |
585 | int ret; |
586 | int unzipped_len; |
587 | char *unzipped, *workspace; |
588 | size_t max_uncompressed_size; |
589 | |
590 | if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed) |
591 | return; |
592 | |
593 | /* Only PSTORE_TYPE_DMESG support compression. */ |
594 | if (record->type != PSTORE_TYPE_DMESG) { |
595 | pr_warn("ignored compressed record type %d\n" , record->type); |
596 | return; |
597 | } |
598 | |
599 | /* Missing compression buffer means compression was not initialized. */ |
600 | if (!zstream->workspace) { |
601 | pr_warn("no decompression method initialized!\n" ); |
602 | return; |
603 | } |
604 | |
605 | ret = zlib_inflateReset(strm: zstream); |
606 | if (ret != Z_OK) { |
607 | pr_err("zlib_inflateReset() failed, ret = %d!\n" , ret); |
608 | return; |
609 | } |
610 | |
611 | /* Allocate enough space to hold max decompression and ECC. */ |
612 | max_uncompressed_size = 3 * psinfo->bufsize; |
613 | workspace = kvzalloc(size: max_uncompressed_size + record->ecc_notice_size, |
614 | GFP_KERNEL); |
615 | if (!workspace) |
616 | return; |
617 | |
618 | zstream->next_in = record->buf; |
619 | zstream->avail_in = record->size; |
620 | zstream->next_out = workspace; |
621 | zstream->avail_out = max_uncompressed_size; |
622 | |
623 | ret = zlib_inflate(strm: zstream, Z_FINISH); |
624 | if (ret != Z_STREAM_END) { |
625 | pr_err_ratelimited("zlib_inflate() failed, ret = %d!\n" , ret); |
626 | kvfree(addr: workspace); |
627 | return; |
628 | } |
629 | |
630 | unzipped_len = zstream->total_out; |
631 | |
632 | /* Append ECC notice to decompressed buffer. */ |
633 | memcpy(workspace + unzipped_len, record->buf + record->size, |
634 | record->ecc_notice_size); |
635 | |
636 | /* Copy decompressed contents into an minimum-sized allocation. */ |
637 | unzipped = kvmemdup(src: workspace, len: unzipped_len + record->ecc_notice_size, |
638 | GFP_KERNEL); |
639 | kvfree(addr: workspace); |
640 | if (!unzipped) |
641 | return; |
642 | |
643 | /* Swap out compressed contents with decompressed contents. */ |
644 | kvfree(addr: record->buf); |
645 | record->buf = unzipped; |
646 | record->size = unzipped_len; |
647 | record->compressed = false; |
648 | } |
649 | |
650 | /* |
651 | * Read all the records from one persistent store backend. Create |
652 | * files in our filesystem. Don't warn about -EEXIST errors |
653 | * when we are re-scanning the backing store looking to add new |
654 | * error records. |
655 | */ |
656 | void pstore_get_backend_records(struct pstore_info *psi, |
657 | struct dentry *root, int quiet) |
658 | { |
659 | int failed = 0; |
660 | unsigned int stop_loop = 65536; |
661 | struct z_stream_s zstream = {}; |
662 | |
663 | if (!psi || !root) |
664 | return; |
665 | |
666 | if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress) { |
667 | zstream.workspace = kvmalloc(size: zlib_inflate_workspacesize(), |
668 | GFP_KERNEL); |
669 | zlib_inflateInit2(strm: &zstream, windowBits: -DEF_WBITS); |
670 | } |
671 | |
672 | mutex_lock(&psi->read_mutex); |
673 | if (psi->open && psi->open(psi)) |
674 | goto out; |
675 | |
676 | /* |
677 | * Backend callback read() allocates record.buf. decompress_record() |
678 | * may reallocate record.buf. On success, pstore_mkfile() will keep |
679 | * the record.buf, so free it only on failure. |
680 | */ |
681 | for (; stop_loop; stop_loop--) { |
682 | struct pstore_record *record; |
683 | int rc; |
684 | |
685 | record = kzalloc(size: sizeof(*record), GFP_KERNEL); |
686 | if (!record) { |
687 | pr_err("out of memory creating record\n" ); |
688 | break; |
689 | } |
690 | pstore_record_init(record, psinfo: psi); |
691 | |
692 | record->size = psi->read(record); |
693 | |
694 | /* No more records left in backend? */ |
695 | if (record->size <= 0) { |
696 | kfree(objp: record); |
697 | break; |
698 | } |
699 | |
700 | decompress_record(record, zstream: &zstream); |
701 | rc = pstore_mkfile(root, record); |
702 | if (rc) { |
703 | /* pstore_mkfile() did not take record, so free it. */ |
704 | kvfree(addr: record->buf); |
705 | kfree(objp: record->priv); |
706 | kfree(objp: record); |
707 | if (rc != -EEXIST || !quiet) |
708 | failed++; |
709 | } |
710 | } |
711 | if (psi->close) |
712 | psi->close(psi); |
713 | out: |
714 | mutex_unlock(lock: &psi->read_mutex); |
715 | |
716 | if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress) { |
717 | if (zlib_inflateEnd(strm: &zstream) != Z_OK) |
718 | pr_warn("zlib_inflateEnd() failed\n" ); |
719 | kvfree(addr: zstream.workspace); |
720 | } |
721 | |
722 | if (failed) |
723 | pr_warn("failed to create %d record(s) from '%s'\n" , |
724 | failed, psi->name); |
725 | if (!stop_loop) |
726 | pr_err("looping? Too many records seen from '%s'\n" , |
727 | psi->name); |
728 | } |
729 | |
730 | static void pstore_dowork(struct work_struct *work) |
731 | { |
732 | pstore_get_records(1); |
733 | } |
734 | |
735 | static void pstore_timefunc(struct timer_list *unused) |
736 | { |
737 | if (pstore_new_entry) { |
738 | pstore_new_entry = 0; |
739 | schedule_work(work: &pstore_work); |
740 | } |
741 | |
742 | pstore_timer_kick(); |
743 | } |
744 | |
745 | static int __init pstore_init(void) |
746 | { |
747 | int ret; |
748 | |
749 | ret = pstore_init_fs(); |
750 | if (ret) |
751 | free_buf_for_compression(); |
752 | |
753 | return ret; |
754 | } |
755 | late_initcall(pstore_init); |
756 | |
757 | static void __exit pstore_exit(void) |
758 | { |
759 | pstore_exit_fs(); |
760 | } |
761 | module_exit(pstore_exit) |
762 | |
763 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>" ); |
764 | MODULE_LICENSE("GPL" ); |
765 | |