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1/*
2 * Persistent Storage - platform driver interface parts.
3 *
4 * Copyright (C) 2007-2008 Google, Inc.
5 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21#define pr_fmt(fmt) "pstore: " fmt
22
23#include <linux/atomic.h>
24#include <linux/types.h>
25#include <linux/errno.h>
26#include <linux/init.h>
27#include <linux/kmsg_dump.h>
28#include <linux/console.h>
29#include <linux/module.h>
30#include <linux/pstore.h>
31#include <linux/zlib.h>
32#include <linux/string.h>
33#include <linux/timer.h>
34#include <linux/slab.h>
35#include <linux/uaccess.h>
36#include <linux/hardirq.h>
37#include <linux/jiffies.h>
38#include <linux/workqueue.h>
39
40#include "internal.h"
41
42/*
43 * We defer making "oops" entries appear in pstore - see
44 * whether the system is actually still running well enough
45 * to let someone see the entry
46 */
47static int pstore_update_ms = -1;
48module_param_named(update_ms, pstore_update_ms, int, 0600);
49MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
50 "(default is -1, which means runtime updates are disabled; "
51 "enabling this option is not safe, it may lead to further "
52 "corruption on Oopses)");
53
54static int pstore_new_entry;
55
56static void pstore_timefunc(unsigned long);
57static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
58
59static void pstore_dowork(struct work_struct *);
60static DECLARE_WORK(pstore_work, pstore_dowork);
61
62/*
63 * pstore_lock just protects "psinfo" during
64 * calls to pstore_register()
65 */
66static DEFINE_SPINLOCK(pstore_lock);
67struct pstore_info *psinfo;
68
69static char *backend;
70
71/* Compression parameters */
72#define COMPR_LEVEL 6
73#define WINDOW_BITS 12
74#define MEM_LEVEL 4
75static struct z_stream_s stream;
76
77static char *big_oops_buf;
78static size_t big_oops_buf_sz;
79
80/* How much of the console log to snapshot */
81static unsigned long kmsg_bytes = 10240;
82
83void pstore_set_kmsg_bytes(int bytes)
84{
85 kmsg_bytes = bytes;
86}
87
88/* Tag each group of saved records with a sequence number */
89static int oopscount;
90
91static const char *get_reason_str(enum kmsg_dump_reason reason)
92{
93 switch (reason) {
94 case KMSG_DUMP_PANIC:
95 return "Panic";
96 case KMSG_DUMP_OOPS:
97 return "Oops";
98 case KMSG_DUMP_EMERG:
99 return "Emergency";
100 case KMSG_DUMP_RESTART:
101 return "Restart";
102 case KMSG_DUMP_HALT:
103 return "Halt";
104 case KMSG_DUMP_POWEROFF:
105 return "Poweroff";
106 default:
107 return "Unknown";
108 }
109}
110
111bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
112{
113 /*
114 * In case of NMI path, pstore shouldn't be blocked
115 * regardless of reason.
116 */
117 if (in_nmi())
118 return true;
119
120 switch (reason) {
121 /* In panic case, other cpus are stopped by smp_send_stop(). */
122 case KMSG_DUMP_PANIC:
123 /* Emergency restart shouldn't be blocked by spin lock. */
124 case KMSG_DUMP_EMERG:
125 return true;
126 default:
127 return false;
128 }
129}
130EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
131
132/* Derived from logfs_compress() */
133static int pstore_compress(const void *in, void *out, size_t inlen,
134 size_t outlen)
135{
136 int err, ret;
137
138 ret = -EIO;
139 err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
140 MEM_LEVEL, Z_DEFAULT_STRATEGY);
141 if (err != Z_OK)
142 goto error;
143
144 stream.next_in = in;
145 stream.avail_in = inlen;
146 stream.total_in = 0;
147 stream.next_out = out;
148 stream.avail_out = outlen;
149 stream.total_out = 0;
150
151 err = zlib_deflate(&stream, Z_FINISH);
152 if (err != Z_STREAM_END)
153 goto error;
154
155 err = zlib_deflateEnd(&stream);
156 if (err != Z_OK)
157 goto error;
158
159 if (stream.total_out >= stream.total_in)
160 goto error;
161
162 ret = stream.total_out;
163error:
164 return ret;
165}
166
167/* Derived from logfs_uncompress */
168static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
169{
170 int err, ret;
171
172 ret = -EIO;
173 err = zlib_inflateInit2(&stream, WINDOW_BITS);
174 if (err != Z_OK)
175 goto error;
176
177 stream.next_in = in;
178 stream.avail_in = inlen;
179 stream.total_in = 0;
180 stream.next_out = out;
181 stream.avail_out = outlen;
182 stream.total_out = 0;
183
184 err = zlib_inflate(&stream, Z_FINISH);
185 if (err != Z_STREAM_END)
186 goto error;
187
188 err = zlib_inflateEnd(&stream);
189 if (err != Z_OK)
190 goto error;
191
192 ret = stream.total_out;
193error:
194 return ret;
195}
196
197static void allocate_buf_for_compression(void)
198{
199 size_t size;
200 size_t cmpr;
201
202 switch (psinfo->bufsize) {
203 /* buffer range for efivars */
204 case 1000 ... 2000:
205 cmpr = 56;
206 break;
207 case 2001 ... 3000:
208 cmpr = 54;
209 break;
210 case 3001 ... 3999:
211 cmpr = 52;
212 break;
213 /* buffer range for nvram, erst */
214 case 4000 ... 10000:
215 cmpr = 45;
216 break;
217 default:
218 cmpr = 60;
219 break;
220 }
221
222 big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
223 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
224 if (big_oops_buf) {
225 size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
226 zlib_inflate_workspacesize());
227 stream.workspace = kmalloc(size, GFP_KERNEL);
228 if (!stream.workspace) {
229 pr_err("No memory for compression workspace; skipping compression\n");
230 kfree(big_oops_buf);
231 big_oops_buf = NULL;
232 }
233 } else {
234 pr_err("No memory for uncompressed data; skipping compression\n");
235 stream.workspace = NULL;
236 }
237
238}
239
240static void free_buf_for_compression(void)
241{
242 kfree(stream.workspace);
243 stream.workspace = NULL;
244 kfree(big_oops_buf);
245 big_oops_buf = NULL;
246}
247
248/*
249 * Called when compression fails, since the printk buffer
250 * would be fetched for compression calling it again when
251 * compression fails would have moved the iterator of
252 * printk buffer which results in fetching old contents.
253 * Copy the recent messages from big_oops_buf to psinfo->buf
254 */
255static size_t copy_kmsg_to_buffer(int hsize, size_t len)
256{
257 size_t total_len;
258 size_t diff;
259
260 total_len = hsize + len;
261
262 if (total_len > psinfo->bufsize) {
263 diff = total_len - psinfo->bufsize + hsize;
264 memcpy(psinfo->buf, big_oops_buf, hsize);
265 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
266 psinfo->bufsize - hsize);
267 total_len = psinfo->bufsize;
268 } else
269 memcpy(psinfo->buf, big_oops_buf, total_len);
270
271 return total_len;
272}
273
274/*
275 * callback from kmsg_dump. (s2,l2) has the most recently
276 * written bytes, older bytes are in (s1,l1). Save as much
277 * as we can from the end of the buffer.
278 */
279static void pstore_dump(struct kmsg_dumper *dumper,
280 enum kmsg_dump_reason reason)
281{
282 unsigned long total = 0;
283 const char *why;
284 u64 id;
285 unsigned int part = 1;
286 unsigned long flags = 0;
287 int is_locked = 0;
288 int ret;
289
290 why = get_reason_str(reason);
291
292 if (pstore_cannot_block_path(reason)) {
293 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
294 if (!is_locked) {
295 pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
296 , in_nmi() ? "NMI" : why);
297 }
298 } else
299 spin_lock_irqsave(&psinfo->buf_lock, flags);
300 oopscount++;
301 while (total < kmsg_bytes) {
302 char *dst;
303 unsigned long size;
304 int hsize;
305 int zipped_len = -1;
306 size_t len;
307 bool compressed;
308 size_t total_len;
309
310 if (big_oops_buf && is_locked) {
311 dst = big_oops_buf;
312 hsize = sprintf(dst, "%s#%d Part%u\n", why,
313 oopscount, part);
314 size = big_oops_buf_sz - hsize;
315
316 if (!kmsg_dump_get_buffer(dumper, true, dst + hsize,
317 size, &len))
318 break;
319
320 zipped_len = pstore_compress(dst, psinfo->buf,
321 hsize + len, psinfo->bufsize);
322
323 if (zipped_len > 0) {
324 compressed = true;
325 total_len = zipped_len;
326 } else {
327 compressed = false;
328 total_len = copy_kmsg_to_buffer(hsize, len);
329 }
330 } else {
331 dst = psinfo->buf;
332 hsize = sprintf(dst, "%s#%d Part%u\n", why, oopscount,
333 part);
334 size = psinfo->bufsize - hsize;
335 dst += hsize;
336
337 if (!kmsg_dump_get_buffer(dumper, true, dst,
338 size, &len))
339 break;
340
341 compressed = false;
342 total_len = hsize + len;
343 }
344
345 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
346 oopscount, compressed, total_len, psinfo);
347 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
348 pstore_new_entry = 1;
349
350 total += total_len;
351 part++;
352 }
353 if (pstore_cannot_block_path(reason)) {
354 if (is_locked)
355 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
356 } else
357 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
358}
359
360static struct kmsg_dumper pstore_dumper = {
361 .dump = pstore_dump,
362};
363
364/*
365 * Register with kmsg_dump to save last part of console log on panic.
366 */
367static void pstore_register_kmsg(void)
368{
369 kmsg_dump_register(&pstore_dumper);
370}
371
372static void pstore_unregister_kmsg(void)
373{
374 kmsg_dump_unregister(&pstore_dumper);
375}
376
377#ifdef CONFIG_PSTORE_CONSOLE
378static void pstore_console_write(struct console *con, const char *s, unsigned c)
379{
380 const char *e = s + c;
381
382 while (s < e) {
383 unsigned long flags;
384 u64 id;
385
386 if (c > psinfo->bufsize)
387 c = psinfo->bufsize;
388
389 if (oops_in_progress) {
390 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
391 break;
392 } else {
393 spin_lock_irqsave(&psinfo->buf_lock, flags);
394 }
395 memcpy(psinfo->buf, s, c);
396 psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
397 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
398 s += c;
399 c = e - s;
400 }
401}
402
403static struct console pstore_console = {
404 .name = "pstore",
405 .write = pstore_console_write,
406 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
407 .index = -1,
408};
409
410static void pstore_register_console(void)
411{
412 register_console(&pstore_console);
413}
414
415static void pstore_unregister_console(void)
416{
417 unregister_console(&pstore_console);
418}
419#else
420static void pstore_register_console(void) {}
421static void pstore_unregister_console(void) {}
422#endif
423
424static int pstore_write_compat(enum pstore_type_id type,
425 enum kmsg_dump_reason reason,
426 u64 *id, unsigned int part, int count,
427 bool compressed, size_t size,
428 struct pstore_info *psi)
429{
430 return psi->write_buf(type, reason, id, part, psinfo->buf, compressed,
431 size, psi);
432}
433
434/*
435 * platform specific persistent storage driver registers with
436 * us here. If pstore is already mounted, call the platform
437 * read function right away to populate the file system. If not
438 * then the pstore mount code will call us later to fill out
439 * the file system.
440 */
441int pstore_register(struct pstore_info *psi)
442{
443 struct module *owner = psi->owner;
444
445 if (backend && strcmp(backend, psi->name))
446 return -EPERM;
447
448 spin_lock(&pstore_lock);
449 if (psinfo) {
450 spin_unlock(&pstore_lock);
451 return -EBUSY;
452 }
453
454 if (!psi->write)
455 psi->write = pstore_write_compat;
456 psinfo = psi;
457 mutex_init(&psinfo->read_mutex);
458 spin_unlock(&pstore_lock);
459
460 if (owner && !try_module_get(owner)) {
461 psinfo = NULL;
462 return -EINVAL;
463 }
464
465 allocate_buf_for_compression();
466
467 if (pstore_is_mounted())
468 pstore_get_records(0);
469
470 pstore_register_kmsg();
471
472 if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
473 pstore_register_console();
474 pstore_register_ftrace();
475 pstore_register_pmsg();
476 }
477
478 if (pstore_update_ms >= 0) {
479 pstore_timer.expires = jiffies +
480 msecs_to_jiffies(pstore_update_ms);
481 add_timer(&pstore_timer);
482 }
483
484 /*
485 * Update the module parameter backend, so it is visible
486 * through /sys/module/pstore/parameters/backend
487 */
488 backend = psi->name;
489
490 module_put(owner);
491
492 pr_info("Registered %s as persistent store backend\n", psi->name);
493
494 return 0;
495}
496EXPORT_SYMBOL_GPL(pstore_register);
497
498void pstore_unregister(struct pstore_info *psi)
499{
500 pstore_unregister_pmsg();
501 pstore_unregister_ftrace();
502 pstore_unregister_console();
503 pstore_unregister_kmsg();
504
505 free_buf_for_compression();
506
507 psinfo = NULL;
508 backend = NULL;
509}
510EXPORT_SYMBOL_GPL(pstore_unregister);
511
512/*
513 * Read all the records from the persistent store. Create
514 * files in our filesystem. Don't warn about -EEXIST errors
515 * when we are re-scanning the backing store looking to add new
516 * error records.
517 */
518void pstore_get_records(int quiet)
519{
520 struct pstore_info *psi = psinfo;
521 char *buf = NULL;
522 ssize_t size;
523 u64 id;
524 int count;
525 enum pstore_type_id type;
526 struct timespec time;
527 int failed = 0, rc;
528 bool compressed;
529 int unzipped_len = -1;
530
531 if (!psi)
532 return;
533
534 mutex_lock(&psi->read_mutex);
535 if (psi->open && psi->open(psi))
536 goto out;
537
538 while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
539 psi)) > 0) {
540 if (compressed && (type == PSTORE_TYPE_DMESG)) {
541 if (big_oops_buf)
542 unzipped_len = pstore_decompress(buf,
543 big_oops_buf, size,
544 big_oops_buf_sz);
545
546 if (unzipped_len > 0) {
547 kfree(buf);
548 buf = big_oops_buf;
549 size = unzipped_len;
550 compressed = false;
551 } else {
552 pr_err("decompression failed;returned %d\n",
553 unzipped_len);
554 compressed = true;
555 }
556 }
557 rc = pstore_mkfile(type, psi->name, id, count, buf,
558 compressed, (size_t)size, time, psi);
559 if (unzipped_len < 0) {
560 /* Free buffer other than big oops */
561 kfree(buf);
562 buf = NULL;
563 } else
564 unzipped_len = -1;
565 if (rc && (rc != -EEXIST || !quiet))
566 failed++;
567 }
568 if (psi->close)
569 psi->close(psi);
570out:
571 mutex_unlock(&psi->read_mutex);
572
573 if (failed)
574 pr_warn("failed to load %d record(s) from '%s'\n",
575 failed, psi->name);
576}
577
578static void pstore_dowork(struct work_struct *work)
579{
580 pstore_get_records(1);
581}
582
583static void pstore_timefunc(unsigned long dummy)
584{
585 if (pstore_new_entry) {
586 pstore_new_entry = 0;
587 schedule_work(&pstore_work);
588 }
589
590 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
591}
592
593module_param(backend, charp, 0444);
594MODULE_PARM_DESC(backend, "Pstore backend to use");
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");