Commit | Line | Data |
---|---|---|
45051539 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
ca01d6dd TL |
2 | /* |
3 | * Persistent Storage - platform driver interface parts. | |
4 | * | |
f29e5956 | 5 | * Copyright (C) 2007-2008 Google, Inc. |
ca01d6dd | 6 | * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com> |
ca01d6dd TL |
7 | */ |
8 | ||
ef748853 FF |
9 | #define pr_fmt(fmt) "pstore: " fmt |
10 | ||
ca01d6dd TL |
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> | |
f29e5956 | 16 | #include <linux/console.h> |
104fd0b5 | 17 | #include <linux/mm.h> |
ca01d6dd TL |
18 | #include <linux/module.h> |
19 | #include <linux/pstore.h> | |
20 | #include <linux/string.h> | |
6dda9266 | 21 | #include <linux/timer.h> |
ca01d6dd TL |
22 | #include <linux/slab.h> |
23 | #include <linux/uaccess.h> | |
a3f5f075 | 24 | #include <linux/jiffies.h> |
438b8050 | 25 | #include <linux/vmalloc.h> |
6dda9266 | 26 | #include <linux/workqueue.h> |
438b8050 | 27 | #include <linux/zlib.h> |
ca01d6dd TL |
28 | |
29 | #include "internal.h" | |
30 | ||
6dda9266 LT |
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 | */ | |
521f7288 | 36 | static int pstore_update_ms = -1; |
a3f5f075 AV |
37 | module_param_named(update_ms, pstore_update_ms, int, 0600); |
38 | MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content " | |
521f7288 | 39 | "(default is -1, which means runtime updates are disabled; " |
78c83c82 | 40 | "enabling this option may not be safe; it may lead to further " |
521f7288 | 41 | "corruption on Oopses)"); |
6dda9266 | 42 | |
f0f23e54 JFG |
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 | ||
6dda9266 LT |
56 | static int pstore_new_entry; |
57 | ||
24ed960a | 58 | static void pstore_timefunc(struct timer_list *); |
1d27e3e2 | 59 | static DEFINE_TIMER(pstore_timer, pstore_timefunc); |
6dda9266 LT |
60 | |
61 | static void pstore_dowork(struct work_struct *); | |
62 | static DECLARE_WORK(pstore_work, pstore_dowork); | |
63 | ||
ca01d6dd | 64 | /* |
6248a066 KC |
65 | * psinfo_lock protects "psinfo" during calls to |
66 | * pstore_register(), pstore_unregister(), and | |
67 | * the filesystem mount/unmount routines. | |
ca01d6dd | 68 | */ |
cab12fd0 | 69 | static DEFINE_MUTEX(psinfo_lock); |
060287b8 | 70 | struct pstore_info *psinfo; |
ca01d6dd | 71 | |
dee28e72 | 72 | static char *backend; |
d973f7d8 KC |
73 | module_param(backend, charp, 0444); |
74 | MODULE_PARM_DESC(backend, "specific backend to use"); | |
75 | ||
438b8050 AB |
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"; | |
d973f7d8 KC |
91 | module_param(compress, charp, 0444); |
92 | MODULE_PARM_DESC(compress, "compression to use"); | |
dee28e72 | 93 | |
8f5de3fd GP |
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 | ||
438b8050 | 99 | static void *compress_workspace; |
8cfc8ddc | 100 | |
94160062 AB |
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 | ||
b0aad7a9 | 107 | static char *big_oops_buf; |
94160062 | 108 | static size_t max_compressed_size; |
b0aad7a9 | 109 | |
366f7e7a | 110 | void pstore_set_kmsg_bytes(int bytes) |
ca01d6dd | 111 | { |
366f7e7a | 112 | kmsg_bytes = bytes; |
ca01d6dd TL |
113 | } |
114 | ||
ca01d6dd TL |
115 | /* Tag each group of saved records with a sequence number */ |
116 | static int oopscount; | |
117 | ||
f0f23e54 JFG |
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 | ||
78c83c82 KC |
142 | static void pstore_timer_kick(void) |
143 | { | |
144 | if (pstore_update_ms < 0) | |
145 | return; | |
146 | ||
147 | mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms)); | |
148 | } | |
149 | ||
8126b1c7 | 150 | static bool pstore_cannot_block_path(enum kmsg_dump_reason reason) |
9f244e9c | 151 | { |
8126b1c7 JH |
152 | /* |
153 | * In case of NMI path, pstore shouldn't be blocked | |
154 | * regardless of reason. | |
155 | */ | |
9f244e9c SA |
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: | |
8126b1c7 JH |
162 | /* |
163 | * Emergency restart shouldn't be blocked by spinning on | |
164 | * pstore_info::buf_lock. | |
165 | */ | |
9f244e9c SA |
166 | case KMSG_DUMP_EMERG: |
167 | return true; | |
168 | default: | |
169 | return false; | |
170 | } | |
171 | } | |
9f244e9c | 172 | |
8cfc8ddc | 173 | static int pstore_compress(const void *in, void *out, |
cb3bee03 | 174 | unsigned int inlen, unsigned int outlen) |
8cfc8ddc | 175 | { |
438b8050 AB |
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 | }; | |
cb3bee03 GT |
183 | int ret; |
184 | ||
19d8e914 | 185 | if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS)) |
fd49e032 MC |
186 | return -EINVAL; |
187 | ||
438b8050 AB |
188 | ret = zlib_deflateInit2(&zstream, Z_DEFAULT_COMPRESSION, Z_DEFLATED, |
189 | -MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY); | |
190 | if (ret != Z_OK) | |
191 | return -EINVAL; | |
cb3bee03 | 192 | |
438b8050 AB |
193 | ret = zlib_deflate(&zstream, Z_FINISH); |
194 | if (ret != Z_STREAM_END) | |
195 | return -EINVAL; | |
196 | ||
197 | ret = zlib_deflateEnd(&zstream); | |
198 | if (ret != Z_OK) | |
199 | pr_warn_once("zlib_deflateEnd() failed: %d\n", ret); | |
200 | ||
201 | return zstream.total_out; | |
8cfc8ddc GT |
202 | } |
203 | ||
8cfc8ddc GT |
204 | static void allocate_buf_for_compression(void) |
205 | { | |
94160062 | 206 | size_t compressed_size; |
95047b05 KC |
207 | char *buf; |
208 | ||
438b8050 AB |
209 | /* Skip if not built-in or compression disabled. */ |
210 | if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !compress || | |
211 | !strcmp(compress, "none")) { | |
212 | compress = NULL; | |
95047b05 | 213 | return; |
438b8050 | 214 | } |
95047b05 | 215 | |
438b8050 AB |
216 | if (strcmp(compress, "deflate")) { |
217 | pr_err("Unsupported compression '%s', falling back to deflate\n", | |
218 | compress); | |
219 | compress = "deflate"; | |
95047b05 | 220 | } |
cb3bee03 | 221 | |
1756ddea AB |
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 | */ | |
94160062 AB |
227 | compressed_size = (psinfo->bufsize * 100) / DMESG_COMP_PERCENT; |
228 | buf = kvzalloc(compressed_size, GFP_KERNEL); | |
95047b05 | 229 | if (!buf) { |
1756ddea AB |
230 | pr_err("Failed %zu byte compression buffer allocation for: %s\n", |
231 | psinfo->bufsize, compress); | |
cb3bee03 GT |
232 | return; |
233 | } | |
234 | ||
438b8050 AB |
235 | compress_workspace = |
236 | vmalloc(zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL)); | |
237 | if (!compress_workspace) { | |
238 | pr_err("Failed to allocate zlib deflate workspace\n"); | |
104fd0b5 | 239 | kvfree(buf); |
cb3bee03 | 240 | return; |
8cfc8ddc | 241 | } |
95047b05 KC |
242 | |
243 | /* A non-NULL big_oops_buf indicates compression is available. */ | |
95047b05 | 244 | big_oops_buf = buf; |
94160062 | 245 | max_compressed_size = compressed_size; |
95047b05 | 246 | |
1756ddea | 247 | pr_info("Using crash dump compression: %s\n", compress); |
8cfc8ddc GT |
248 | } |
249 | ||
250 | static void free_buf_for_compression(void) | |
251 | { | |
438b8050 AB |
252 | if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress_workspace) { |
253 | vfree(compress_workspace); | |
254 | compress_workspace = NULL; | |
a9fb94a9 | 255 | } |
438b8050 | 256 | |
104fd0b5 | 257 | kvfree(big_oops_buf); |
cb3bee03 | 258 | big_oops_buf = NULL; |
94160062 | 259 | max_compressed_size = 0; |
b0aad7a9 AB |
260 | } |
261 | ||
e581ca81 KC |
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; | |
c7f3c595 KC |
268 | |
269 | /* Report zeroed timestamp if called before timekeeping has resumed. */ | |
7aaa822e | 270 | record->time = ns_to_timespec64(ktime_get_real_fast_ns()); |
e581ca81 KC |
271 | } |
272 | ||
ca01d6dd | 273 | /* |
0eed84ff KC |
274 | * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the |
275 | * end of the buffer. | |
ca01d6dd TL |
276 | */ |
277 | static void pstore_dump(struct kmsg_dumper *dumper, | |
e2ae715d | 278 | enum kmsg_dump_reason reason) |
ca01d6dd | 279 | { |
f9f3f02d | 280 | struct kmsg_dump_iter iter; |
e2ae715d | 281 | unsigned long total = 0; |
381b872c | 282 | const char *why; |
b94fdd07 | 283 | unsigned int part = 1; |
8126b1c7 | 284 | unsigned long flags = 0; |
38b91847 | 285 | int saved_ret = 0; |
e2ae715d | 286 | int ret; |
ca01d6dd | 287 | |
fb13cb8a | 288 | why = kmsg_dump_reason_str(reason); |
9f6af27f | 289 | |
8126b1c7 JH |
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); | |
959217c8 | 294 | return; |
9f244e9c | 295 | } |
8126b1c7 JH |
296 | } else { |
297 | spin_lock_irqsave(&psinfo->buf_lock, flags); | |
98e44fda | 298 | } |
ea84b580 | 299 | |
f9f3f02d JO |
300 | kmsg_dump_rewind(&iter); |
301 | ||
ca01d6dd TL |
302 | oopscount++; |
303 | while (total < kmsg_bytes) { | |
e2ae715d | 304 | char *dst; |
76cc9580 KC |
305 | size_t dst_size; |
306 | int header_size; | |
b0aad7a9 | 307 | int zipped_len = -1; |
76cc9580 | 308 | size_t dump_size; |
e581ca81 KC |
309 | struct pstore_record record; |
310 | ||
311 | pstore_record_init(&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; | |
e2ae715d | 317 | |
1756ddea | 318 | dst = big_oops_buf ?: psinfo->buf; |
94160062 | 319 | dst_size = max_compressed_size ?: psinfo->bufsize; |
235f6d15 | 320 | |
76cc9580 KC |
321 | /* Write dump header. */ |
322 | header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why, | |
323 | oopscount, part); | |
324 | dst_size -= header_size; | |
ca01d6dd | 325 | |
76cc9580 | 326 | /* Write dump contents. */ |
f9f3f02d | 327 | if (!kmsg_dump_get_buffer(&iter, true, dst + header_size, |
76cc9580 | 328 | dst_size, &dump_size)) |
235f6d15 | 329 | break; |
b0aad7a9 | 330 | |
ea84b580 | 331 | if (big_oops_buf) { |
b0aad7a9 | 332 | zipped_len = pstore_compress(dst, psinfo->buf, |
76cc9580 KC |
333 | header_size + dump_size, |
334 | psinfo->bufsize); | |
b0aad7a9 AB |
335 | |
336 | if (zipped_len > 0) { | |
76cc9580 KC |
337 | record.compressed = true; |
338 | record.size = zipped_len; | |
b0aad7a9 | 339 | } else { |
94160062 AB |
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); | |
b0aad7a9 AB |
349 | } |
350 | } else { | |
76cc9580 | 351 | record.size = header_size + dump_size; |
b0aad7a9 | 352 | } |
ca01d6dd | 353 | |
76cc9580 | 354 | ret = psinfo->write(&record); |
78c83c82 | 355 | if (ret == 0 && reason == KMSG_DUMP_OOPS) { |
6dda9266 | 356 | pstore_new_entry = 1; |
78c83c82 | 357 | pstore_timer_kick(); |
38b91847 GP |
358 | } else { |
359 | /* Preserve only the first non-zero returned value. */ | |
360 | if (!saved_ret) | |
361 | saved_ret = ret; | |
78c83c82 | 362 | } |
e2ae715d | 363 | |
76cc9580 | 364 | total += record.size; |
56280682 | 365 | part++; |
ca01d6dd | 366 | } |
8126b1c7 | 367 | spin_unlock_irqrestore(&psinfo->buf_lock, flags); |
38b91847 GP |
368 | |
369 | if (saved_ret) { | |
370 | pr_err_once("backend (%s) writing error (%d)\n", psinfo->name, | |
371 | saved_ret); | |
372 | } | |
ca01d6dd TL |
373 | } |
374 | ||
375 | static struct kmsg_dumper pstore_dumper = { | |
376 | .dump = pstore_dump, | |
377 | }; | |
378 | ||
306e5c2a GT |
379 | /* |
380 | * Register with kmsg_dump to save last part of console log on panic. | |
381 | */ | |
18730411 GT |
382 | static void pstore_register_kmsg(void) |
383 | { | |
384 | kmsg_dump_register(&pstore_dumper); | |
385 | } | |
386 | ||
ee1d2674 GT |
387 | static void pstore_unregister_kmsg(void) |
388 | { | |
389 | kmsg_dump_unregister(&pstore_dumper); | |
390 | } | |
391 | ||
f29e5956 AV |
392 | #ifdef CONFIG_PSTORE_CONSOLE |
393 | static void pstore_console_write(struct console *con, const char *s, unsigned c) | |
394 | { | |
b77fa617 | 395 | struct pstore_record record; |
f29e5956 | 396 | |
4c6c4d34 YH |
397 | if (!c) |
398 | return; | |
399 | ||
b77fa617 KC |
400 | pstore_record_init(&record, psinfo); |
401 | record.type = PSTORE_TYPE_CONSOLE; | |
80c9d03c | 402 | |
b77fa617 KC |
403 | record.buf = (char *)s; |
404 | record.size = c; | |
405 | psinfo->write(&record); | |
f29e5956 AV |
406 | } |
407 | ||
408 | static struct console pstore_console = { | |
f29e5956 | 409 | .write = pstore_console_write, |
f29e5956 AV |
410 | .index = -1, |
411 | }; | |
412 | ||
413 | static void pstore_register_console(void) | |
414 | { | |
d195c390 KC |
415 | /* Show which backend is going to get console writes. */ |
416 | strscpy(pstore_console.name, psinfo->name, | |
417 | sizeof(pstore_console.name)); | |
b7753fc7 KC |
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; | |
f29e5956 AV |
423 | register_console(&pstore_console); |
424 | } | |
ee1d2674 GT |
425 | |
426 | static void pstore_unregister_console(void) | |
427 | { | |
428 | unregister_console(&pstore_console); | |
429 | } | |
f29e5956 AV |
430 | #else |
431 | static void pstore_register_console(void) {} | |
ee1d2674 | 432 | static void pstore_unregister_console(void) {} |
f29e5956 AV |
433 | #endif |
434 | ||
4c9ec219 KC |
435 | static int pstore_write_user_compat(struct pstore_record *record, |
436 | const char __user *buf) | |
5bf6d1b9 | 437 | { |
30800d99 KC |
438 | int ret = 0; |
439 | ||
440 | if (record->buf) | |
441 | return -EINVAL; | |
442 | ||
104fd0b5 | 443 | record->buf = vmemdup_user(buf, record->size); |
dfd6fa39 | 444 | if (IS_ERR(record->buf)) { |
077090af | 445 | ret = PTR_ERR(record->buf); |
30800d99 | 446 | goto out; |
5bf6d1b9 | 447 | } |
30800d99 KC |
448 | |
449 | ret = record->psi->write(record); | |
450 | ||
104fd0b5 | 451 | kvfree(record->buf); |
077090af | 452 | out: |
30800d99 KC |
453 | record->buf = NULL; |
454 | ||
455 | return unlikely(ret < 0) ? ret : record->size; | |
5bf6d1b9 MS |
456 | } |
457 | ||
ca01d6dd TL |
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. | |
ca01d6dd TL |
464 | */ |
465 | int pstore_register(struct pstore_info *psi) | |
466 | { | |
a19d48f7 JJ |
467 | char *new_backend; |
468 | ||
0d7cd09a | 469 | if (backend && strcmp(backend, psi->name)) { |
d85644dc GP |
470 | pr_warn("backend '%s' already in use: ignoring '%s'\n", |
471 | backend, psi->name); | |
472 | return -EBUSY; | |
0d7cd09a | 473 | } |
8e48b1a8 | 474 | |
4c9ec219 KC |
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 | ||
a19d48f7 JJ |
489 | new_backend = kstrdup(psi->name, GFP_KERNEL); |
490 | if (!new_backend) | |
491 | return -ENOMEM; | |
492 | ||
cab12fd0 | 493 | mutex_lock(&psinfo_lock); |
ca01d6dd | 494 | if (psinfo) { |
0d7cd09a KC |
495 | pr_warn("backend '%s' already loaded: ignoring '%s'\n", |
496 | psinfo->name, psi->name); | |
cab12fd0 | 497 | mutex_unlock(&psinfo_lock); |
a19d48f7 | 498 | kfree(new_backend); |
ca01d6dd TL |
499 | return -EBUSY; |
500 | } | |
dee28e72 | 501 | |
4c9ec219 KC |
502 | if (!psi->write_user) |
503 | psi->write_user = pstore_write_user_compat; | |
ca01d6dd | 504 | psinfo = psi; |
f6f82851 | 505 | mutex_init(&psinfo->read_mutex); |
8126b1c7 | 506 | spin_lock_init(&psinfo->buf_lock); |
ca01d6dd | 507 | |
8880fa32 KC |
508 | if (psi->flags & PSTORE_FLAGS_DMESG) |
509 | allocate_buf_for_compression(); | |
b0aad7a9 | 510 | |
27e5041a | 511 | pstore_get_records(0); |
ca01d6dd | 512 | |
3524e688 PT |
513 | if (psi->flags & PSTORE_FLAGS_DMESG) { |
514 | pstore_dumper.max_reason = psinfo->max_reason; | |
c950fd6f | 515 | pstore_register_kmsg(); |
3524e688 | 516 | } |
c950fd6f | 517 | if (psi->flags & PSTORE_FLAGS_CONSOLE) |
df36ac1b | 518 | pstore_register_console(); |
c950fd6f | 519 | if (psi->flags & PSTORE_FLAGS_FTRACE) |
df36ac1b | 520 | pstore_register_ftrace(); |
c950fd6f | 521 | if (psi->flags & PSTORE_FLAGS_PMSG) |
9d5438f4 | 522 | pstore_register_pmsg(); |
ca01d6dd | 523 | |
6330d553 | 524 | /* Start watching for new records, if desired. */ |
78c83c82 | 525 | pstore_timer_kick(); |
6dda9266 | 526 | |
42222c2a WL |
527 | /* |
528 | * Update the module parameter backend, so it is visible | |
529 | * through /sys/module/pstore/parameters/backend | |
530 | */ | |
a19d48f7 | 531 | backend = new_backend; |
42222c2a | 532 | |
ef748853 | 533 | pr_info("Registered %s as persistent store backend\n", psi->name); |
8e48b1a8 | 534 | |
6248a066 | 535 | mutex_unlock(&psinfo_lock); |
ca01d6dd TL |
536 | return 0; |
537 | } | |
538 | EXPORT_SYMBOL_GPL(pstore_register); | |
539 | ||
ee1d2674 GT |
540 | void pstore_unregister(struct pstore_info *psi) |
541 | { | |
6248a066 KC |
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(&psinfo_lock); | |
551 | return; | |
552 | } | |
553 | ||
78c83c82 | 554 | /* Unregister all callbacks. */ |
c950fd6f | 555 | if (psi->flags & PSTORE_FLAGS_PMSG) |
a1db8060 | 556 | pstore_unregister_pmsg(); |
c950fd6f | 557 | if (psi->flags & PSTORE_FLAGS_FTRACE) |
a1db8060 | 558 | pstore_unregister_ftrace(); |
c950fd6f | 559 | if (psi->flags & PSTORE_FLAGS_CONSOLE) |
a1db8060 | 560 | pstore_unregister_console(); |
c950fd6f NK |
561 | if (psi->flags & PSTORE_FLAGS_DMESG) |
562 | pstore_unregister_kmsg(); | |
ee1d2674 | 563 | |
78c83c82 KC |
564 | /* Stop timer and make sure all work has finished. */ |
565 | del_timer_sync(&pstore_timer); | |
566 | flush_work(&pstore_work); | |
567 | ||
609e28bb KC |
568 | /* Remove all backend records from filesystem tree. */ |
569 | pstore_put_backend_records(psi); | |
570 | ||
ee1d2674 GT |
571 | free_buf_for_compression(); |
572 | ||
573 | psinfo = NULL; | |
563ca40d | 574 | kfree(backend); |
ee1d2674 | 575 | backend = NULL; |
6a14f198 GP |
576 | |
577 | pr_info("Unregistered %s as persistent store backend\n", psi->name); | |
6248a066 | 578 | mutex_unlock(&psinfo_lock); |
ee1d2674 GT |
579 | } |
580 | EXPORT_SYMBOL_GPL(pstore_unregister); | |
581 | ||
438b8050 AB |
582 | static void decompress_record(struct pstore_record *record, |
583 | struct z_stream_s *zstream) | |
634f8f51 | 584 | { |
bdabc8e7 | 585 | int ret; |
634f8f51 | 586 | int unzipped_len; |
bdabc8e7 | 587 | char *unzipped, *workspace; |
94160062 | 588 | size_t max_uncompressed_size; |
634f8f51 | 589 | |
19d8e914 | 590 | if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed) |
4a16d1cb AK |
591 | return; |
592 | ||
634f8f51 | 593 | /* Only PSTORE_TYPE_DMESG support compression. */ |
4a16d1cb | 594 | if (record->type != PSTORE_TYPE_DMESG) { |
634f8f51 KC |
595 | pr_warn("ignored compressed record type %d\n", record->type); |
596 | return; | |
597 | } | |
598 | ||
bdabc8e7 | 599 | /* Missing compression buffer means compression was not initialized. */ |
438b8050 | 600 | if (!zstream->workspace) { |
bdabc8e7 | 601 | pr_warn("no decompression method initialized!\n"); |
634f8f51 KC |
602 | return; |
603 | } | |
604 | ||
438b8050 AB |
605 | ret = zlib_inflateReset(zstream); |
606 | if (ret != Z_OK) { | |
607 | pr_err("zlib_inflateReset() failed, ret = %d!\n", ret); | |
608 | return; | |
609 | } | |
610 | ||
bdabc8e7 | 611 | /* Allocate enough space to hold max decompression and ECC. */ |
94160062 AB |
612 | max_uncompressed_size = 3 * psinfo->bufsize; |
613 | workspace = kvzalloc(max_uncompressed_size + record->ecc_notice_size, | |
104fd0b5 | 614 | GFP_KERNEL); |
bdabc8e7 | 615 | if (!workspace) |
7e8cc8dc | 616 | return; |
7e8cc8dc | 617 | |
438b8050 AB |
618 | zstream->next_in = record->buf; |
619 | zstream->avail_in = record->size; | |
620 | zstream->next_out = workspace; | |
94160062 | 621 | zstream->avail_out = max_uncompressed_size; |
438b8050 AB |
622 | |
623 | ret = zlib_inflate(zstream, Z_FINISH); | |
624 | if (ret != Z_STREAM_END) { | |
94160062 | 625 | pr_err_ratelimited("zlib_inflate() failed, ret = %d!\n", ret); |
104fd0b5 | 626 | kvfree(workspace); |
7e8cc8dc KC |
627 | return; |
628 | } | |
7e8cc8dc | 629 | |
438b8050 AB |
630 | unzipped_len = zstream->total_out; |
631 | ||
7e8cc8dc | 632 | /* Append ECC notice to decompressed buffer. */ |
bdabc8e7 | 633 | memcpy(workspace + unzipped_len, record->buf + record->size, |
7e8cc8dc KC |
634 | record->ecc_notice_size); |
635 | ||
bdabc8e7 | 636 | /* Copy decompressed contents into an minimum-sized allocation. */ |
104fd0b5 YZ |
637 | unzipped = kvmemdup(workspace, unzipped_len + record->ecc_notice_size, |
638 | GFP_KERNEL); | |
639 | kvfree(workspace); | |
bdabc8e7 KC |
640 | if (!unzipped) |
641 | return; | |
642 | ||
643 | /* Swap out compressed contents with decompressed contents. */ | |
104fd0b5 | 644 | kvfree(record->buf); |
bdabc8e7 | 645 | record->buf = unzipped; |
7e8cc8dc KC |
646 | record->size = unzipped_len; |
647 | record->compressed = false; | |
634f8f51 KC |
648 | } |
649 | ||
ca01d6dd | 650 | /* |
3a7d2fd1 | 651 | * Read all the records from one persistent store backend. Create |
6dda9266 LT |
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. | |
ca01d6dd | 655 | */ |
3a7d2fd1 KC |
656 | void pstore_get_backend_records(struct pstore_info *psi, |
657 | struct dentry *root, int quiet) | |
ca01d6dd | 658 | { |
2a2b0acf | 659 | int failed = 0; |
656de42e | 660 | unsigned int stop_loop = 65536; |
438b8050 | 661 | struct z_stream_s zstream = {}; |
ca01d6dd | 662 | |
3a7d2fd1 | 663 | if (!psi || !root) |
ca01d6dd TL |
664 | return; |
665 | ||
438b8050 AB |
666 | if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress) { |
667 | zstream.workspace = kvmalloc(zlib_inflate_workspacesize(), | |
668 | GFP_KERNEL); | |
669 | zlib_inflateInit2(&zstream, -DEF_WBITS); | |
670 | } | |
671 | ||
f6f82851 | 672 | mutex_lock(&psi->read_mutex); |
2174f6df | 673 | if (psi->open && psi->open(psi)) |
06cf91b4 CG |
674 | goto out; |
675 | ||
1dfff7dd KC |
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 | */ | |
656de42e | 681 | for (; stop_loop; stop_loop--) { |
2a2b0acf KC |
682 | struct pstore_record *record; |
683 | int rc; | |
684 | ||
685 | record = kzalloc(sizeof(*record), GFP_KERNEL); | |
686 | if (!record) { | |
687 | pr_err("out of memory creating record\n"); | |
688 | break; | |
689 | } | |
e581ca81 | 690 | pstore_record_init(record, psi); |
2a2b0acf KC |
691 | |
692 | record->size = psi->read(record); | |
693 | ||
694 | /* No more records left in backend? */ | |
f6525b96 DA |
695 | if (record->size <= 0) { |
696 | kfree(record); | |
2a2b0acf | 697 | break; |
f6525b96 | 698 | } |
2a2b0acf | 699 | |
438b8050 | 700 | decompress_record(record, &zstream); |
3a7d2fd1 | 701 | rc = pstore_mkfile(root, record); |
1dfff7dd | 702 | if (rc) { |
83f70f07 | 703 | /* pstore_mkfile() did not take record, so free it. */ |
104fd0b5 | 704 | kvfree(record->buf); |
8ca869b2 | 705 | kfree(record->priv); |
83f70f07 | 706 | kfree(record); |
1dfff7dd KC |
707 | if (rc != -EEXIST || !quiet) |
708 | failed++; | |
709 | } | |
ca01d6dd | 710 | } |
2174f6df KC |
711 | if (psi->close) |
712 | psi->close(psi); | |
06cf91b4 | 713 | out: |
f6f82851 | 714 | mutex_unlock(&psi->read_mutex); |
ca01d6dd | 715 | |
438b8050 AB |
716 | if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress) { |
717 | if (zlib_inflateEnd(&zstream) != Z_OK) | |
718 | pr_warn("zlib_inflateEnd() failed\n"); | |
719 | kvfree(zstream.workspace); | |
720 | } | |
721 | ||
ca01d6dd | 722 | if (failed) |
656de42e | 723 | pr_warn("failed to create %d record(s) from '%s'\n", |
ef748853 | 724 | failed, psi->name); |
656de42e KC |
725 | if (!stop_loop) |
726 | pr_err("looping? Too many records seen from '%s'\n", | |
727 | psi->name); | |
ca01d6dd TL |
728 | } |
729 | ||
6dda9266 LT |
730 | static void pstore_dowork(struct work_struct *work) |
731 | { | |
732 | pstore_get_records(1); | |
733 | } | |
734 | ||
24ed960a | 735 | static void pstore_timefunc(struct timer_list *unused) |
6dda9266 LT |
736 | { |
737 | if (pstore_new_entry) { | |
738 | pstore_new_entry = 0; | |
739 | schedule_work(&pstore_work); | |
740 | } | |
741 | ||
78c83c82 | 742 | pstore_timer_kick(); |
6dda9266 LT |
743 | } |
744 | ||
cb095afd KC |
745 | static int __init pstore_init(void) |
746 | { | |
747 | int ret; | |
748 | ||
cb095afd KC |
749 | ret = pstore_init_fs(); |
750 | if (ret) | |
8a57d6d4 | 751 | free_buf_for_compression(); |
cb095afd | 752 | |
8a57d6d4 | 753 | return ret; |
cb095afd | 754 | } |
41603165 | 755 | late_initcall(pstore_init); |
cb095afd KC |
756 | |
757 | static void __exit pstore_exit(void) | |
758 | { | |
759 | pstore_exit_fs(); | |
760 | } | |
761 | module_exit(pstore_exit) | |
762 | ||
cb095afd KC |
763 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); |
764 | MODULE_LICENSE("GPL"); |