| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * Persistent Storage - platform driver interface parts. |
| 4 | * |
| 5 | * Copyright (C) 2007-2008 Google, Inc. |
| 6 | * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com> |
| 7 | */ |
| 8 | |
| 9 | #define pr_fmt(fmt) "pstore: " fmt |
| 10 | |
| 11 | #include <linux/atomic.h> |
| 12 | #include <linux/types.h> |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/kmsg_dump.h> |
| 16 | #include <linux/console.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/pstore.h> |
| 19 | #if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS) |
| 20 | #include <linux/lzo.h> |
| 21 | #endif |
| 22 | #if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS) |
| 23 | #include <linux/lz4.h> |
| 24 | #endif |
| 25 | #if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS) |
| 26 | #include <linux/zstd.h> |
| 27 | #endif |
| 28 | #include <linux/crypto.h> |
| 29 | #include <linux/string.h> |
| 30 | #include <linux/timer.h> |
| 31 | #include <linux/slab.h> |
| 32 | #include <linux/uaccess.h> |
| 33 | #include <linux/jiffies.h> |
| 34 | #include <linux/workqueue.h> |
| 35 | |
| 36 | #include "internal.h" |
| 37 | |
| 38 | /* |
| 39 | * We defer making "oops" entries appear in pstore - see |
| 40 | * whether the system is actually still running well enough |
| 41 | * to let someone see the entry |
| 42 | */ |
| 43 | static int pstore_update_ms = -1; |
| 44 | module_param_named(update_ms, pstore_update_ms, int, 0600); |
| 45 | MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content " |
| 46 | "(default is -1, which means runtime updates are disabled; " |
| 47 | "enabling this option may not be safe; it may lead to further " |
| 48 | "corruption on Oopses)"); |
| 49 | |
| 50 | /* Names should be in the same order as the enum pstore_type_id */ |
| 51 | static const char * const pstore_type_names[] = { |
| 52 | "dmesg", |
| 53 | "mce", |
| 54 | "console", |
| 55 | "ftrace", |
| 56 | "rtas", |
| 57 | "powerpc-ofw", |
| 58 | "powerpc-common", |
| 59 | "pmsg", |
| 60 | "powerpc-opal", |
| 61 | }; |
| 62 | |
| 63 | static int pstore_new_entry; |
| 64 | |
| 65 | static void pstore_timefunc(struct timer_list *); |
| 66 | static DEFINE_TIMER(pstore_timer, pstore_timefunc); |
| 67 | |
| 68 | static void pstore_dowork(struct work_struct *); |
| 69 | static DECLARE_WORK(pstore_work, pstore_dowork); |
| 70 | |
| 71 | /* |
| 72 | * psinfo_lock protects "psinfo" during calls to |
| 73 | * pstore_register(), pstore_unregister(), and |
| 74 | * the filesystem mount/unmount routines. |
| 75 | */ |
| 76 | static DEFINE_MUTEX(psinfo_lock); |
| 77 | struct pstore_info *psinfo; |
| 78 | |
| 79 | static char *backend; |
| 80 | module_param(backend, charp, 0444); |
| 81 | MODULE_PARM_DESC(backend, "specific backend to use"); |
| 82 | |
| 83 | static char *compress = |
| 84 | #ifdef CONFIG_PSTORE_COMPRESS_DEFAULT |
| 85 | CONFIG_PSTORE_COMPRESS_DEFAULT; |
| 86 | #else |
| 87 | NULL; |
| 88 | #endif |
| 89 | module_param(compress, charp, 0444); |
| 90 | MODULE_PARM_DESC(compress, "compression to use"); |
| 91 | |
| 92 | /* Compression parameters */ |
| 93 | static struct crypto_comp *tfm; |
| 94 | |
| 95 | struct pstore_zbackend { |
| 96 | int (*zbufsize)(size_t size); |
| 97 | const char *name; |
| 98 | }; |
| 99 | |
| 100 | static char *big_oops_buf; |
| 101 | static size_t big_oops_buf_sz; |
| 102 | |
| 103 | /* How much of the console log to snapshot */ |
| 104 | unsigned long kmsg_bytes = PSTORE_DEFAULT_KMSG_BYTES; |
| 105 | |
| 106 | void pstore_set_kmsg_bytes(int bytes) |
| 107 | { |
| 108 | kmsg_bytes = bytes; |
| 109 | } |
| 110 | |
| 111 | /* Tag each group of saved records with a sequence number */ |
| 112 | static int oopscount; |
| 113 | |
| 114 | const char *pstore_type_to_name(enum pstore_type_id type) |
| 115 | { |
| 116 | BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX); |
| 117 | |
| 118 | if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX)) |
| 119 | return "unknown"; |
| 120 | |
| 121 | return pstore_type_names[type]; |
| 122 | } |
| 123 | EXPORT_SYMBOL_GPL(pstore_type_to_name); |
| 124 | |
| 125 | enum pstore_type_id pstore_name_to_type(const char *name) |
| 126 | { |
| 127 | int i; |
| 128 | |
| 129 | for (i = 0; i < PSTORE_TYPE_MAX; i++) { |
| 130 | if (!strcmp(pstore_type_names[i], name)) |
| 131 | return i; |
| 132 | } |
| 133 | |
| 134 | return PSTORE_TYPE_MAX; |
| 135 | } |
| 136 | EXPORT_SYMBOL_GPL(pstore_name_to_type); |
| 137 | |
| 138 | static void pstore_timer_kick(void) |
| 139 | { |
| 140 | if (pstore_update_ms < 0) |
| 141 | return; |
| 142 | |
| 143 | mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms)); |
| 144 | } |
| 145 | |
| 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 | */ |
| 151 | static 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) |
| 169 | static 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) |
| 198 | static 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) |
| 205 | static int zbufsize_lz4(size_t size) |
| 206 | { |
| 207 | return LZ4_compressBound(size); |
| 208 | } |
| 209 | #endif |
| 210 | |
| 211 | #if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS) |
| 212 | static int zbufsize_842(size_t size) |
| 213 | { |
| 214 | return size; |
| 215 | } |
| 216 | #endif |
| 217 | |
| 218 | #if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS) |
| 219 | static int zbufsize_zstd(size_t size) |
| 220 | { |
| 221 | return ZSTD_compressBound(size); |
| 222 | } |
| 223 | #endif |
| 224 | |
| 225 | static const struct pstore_zbackend *zbackend __ro_after_init; |
| 226 | |
| 227 | static 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 | |
| 267 | static int pstore_compress(const void *in, void *out, |
| 268 | unsigned int inlen, unsigned int outlen) |
| 269 | { |
| 270 | int ret; |
| 271 | |
| 272 | ret = crypto_comp_compress(tfm, in, inlen, out, &outlen); |
| 273 | if (ret) { |
| 274 | pr_err("crypto_comp_compress failed, ret = %d!\n", ret); |
| 275 | return ret; |
| 276 | } |
| 277 | |
| 278 | return outlen; |
| 279 | } |
| 280 | |
| 281 | static void allocate_buf_for_compression(void) |
| 282 | { |
| 283 | struct crypto_comp *ctx; |
| 284 | int size; |
| 285 | char *buf; |
| 286 | |
| 287 | /* Skip if not built-in or compression backend not selected yet. */ |
| 288 | if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend) |
| 289 | return; |
| 290 | |
| 291 | /* Skip if no pstore backend yet or compression init already done. */ |
| 292 | if (!psinfo || tfm) |
| 293 | return; |
| 294 | |
| 295 | if (!crypto_has_comp(zbackend->name, 0, 0)) { |
| 296 | pr_err("Unknown compression: %s\n", zbackend->name); |
| 297 | return; |
| 298 | } |
| 299 | |
| 300 | size = zbackend->zbufsize(psinfo->bufsize); |
| 301 | if (size <= 0) { |
| 302 | pr_err("Invalid compression size for %s: %d\n", |
| 303 | zbackend->name, size); |
| 304 | return; |
| 305 | } |
| 306 | |
| 307 | buf = kmalloc(size, GFP_KERNEL); |
| 308 | if (!buf) { |
| 309 | pr_err("Failed %d byte compression buffer allocation for: %s\n", |
| 310 | size, zbackend->name); |
| 311 | return; |
| 312 | } |
| 313 | |
| 314 | ctx = crypto_alloc_comp(zbackend->name, 0, 0); |
| 315 | if (IS_ERR_OR_NULL(ctx)) { |
| 316 | kfree(buf); |
| 317 | pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name, |
| 318 | PTR_ERR(ctx)); |
| 319 | return; |
| 320 | } |
| 321 | |
| 322 | /* A non-NULL big_oops_buf indicates compression is available. */ |
| 323 | tfm = ctx; |
| 324 | big_oops_buf_sz = size; |
| 325 | big_oops_buf = buf; |
| 326 | |
| 327 | pr_info("Using crash dump compression: %s\n", zbackend->name); |
| 328 | } |
| 329 | |
| 330 | static void free_buf_for_compression(void) |
| 331 | { |
| 332 | if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) { |
| 333 | crypto_free_comp(tfm); |
| 334 | tfm = NULL; |
| 335 | } |
| 336 | kfree(big_oops_buf); |
| 337 | big_oops_buf = NULL; |
| 338 | big_oops_buf_sz = 0; |
| 339 | } |
| 340 | |
| 341 | /* |
| 342 | * Called when compression fails, since the printk buffer |
| 343 | * would be fetched for compression calling it again when |
| 344 | * compression fails would have moved the iterator of |
| 345 | * printk buffer which results in fetching old contents. |
| 346 | * Copy the recent messages from big_oops_buf to psinfo->buf |
| 347 | */ |
| 348 | static size_t copy_kmsg_to_buffer(int hsize, size_t len) |
| 349 | { |
| 350 | size_t total_len; |
| 351 | size_t diff; |
| 352 | |
| 353 | total_len = hsize + len; |
| 354 | |
| 355 | if (total_len > psinfo->bufsize) { |
| 356 | diff = total_len - psinfo->bufsize + hsize; |
| 357 | memcpy(psinfo->buf, big_oops_buf, hsize); |
| 358 | memcpy(psinfo->buf + hsize, big_oops_buf + diff, |
| 359 | psinfo->bufsize - hsize); |
| 360 | total_len = psinfo->bufsize; |
| 361 | } else |
| 362 | memcpy(psinfo->buf, big_oops_buf, total_len); |
| 363 | |
| 364 | return total_len; |
| 365 | } |
| 366 | |
| 367 | void pstore_record_init(struct pstore_record *record, |
| 368 | struct pstore_info *psinfo) |
| 369 | { |
| 370 | memset(record, 0, sizeof(*record)); |
| 371 | |
| 372 | record->psi = psinfo; |
| 373 | |
| 374 | /* Report zeroed timestamp if called before timekeeping has resumed. */ |
| 375 | record->time = ns_to_timespec64(ktime_get_real_fast_ns()); |
| 376 | } |
| 377 | |
| 378 | /* |
| 379 | * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the |
| 380 | * end of the buffer. |
| 381 | */ |
| 382 | static void pstore_dump(struct kmsg_dumper *dumper, |
| 383 | enum kmsg_dump_reason reason) |
| 384 | { |
| 385 | unsigned long total = 0; |
| 386 | const char *why; |
| 387 | unsigned int part = 1; |
| 388 | int ret; |
| 389 | |
| 390 | why = kmsg_dump_reason_str(reason); |
| 391 | |
| 392 | if (down_trylock(&psinfo->buf_lock)) { |
| 393 | /* Failed to acquire lock: give up if we cannot wait. */ |
| 394 | if (pstore_cannot_wait(reason)) { |
| 395 | pr_err("dump skipped in %s path: may corrupt error record\n", |
| 396 | in_nmi() ? "NMI" : why); |
| 397 | return; |
| 398 | } |
| 399 | if (down_interruptible(&psinfo->buf_lock)) { |
| 400 | pr_err("could not grab semaphore?!\n"); |
| 401 | return; |
| 402 | } |
| 403 | } |
| 404 | |
| 405 | oopscount++; |
| 406 | while (total < kmsg_bytes) { |
| 407 | char *dst; |
| 408 | size_t dst_size; |
| 409 | int header_size; |
| 410 | int zipped_len = -1; |
| 411 | size_t dump_size; |
| 412 | struct pstore_record record; |
| 413 | |
| 414 | pstore_record_init(&record, psinfo); |
| 415 | record.type = PSTORE_TYPE_DMESG; |
| 416 | record.count = oopscount; |
| 417 | record.reason = reason; |
| 418 | record.part = part; |
| 419 | record.buf = psinfo->buf; |
| 420 | |
| 421 | if (big_oops_buf) { |
| 422 | dst = big_oops_buf; |
| 423 | dst_size = big_oops_buf_sz; |
| 424 | } else { |
| 425 | dst = psinfo->buf; |
| 426 | dst_size = psinfo->bufsize; |
| 427 | } |
| 428 | |
| 429 | /* Write dump header. */ |
| 430 | header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why, |
| 431 | oopscount, part); |
| 432 | dst_size -= header_size; |
| 433 | |
| 434 | /* Write dump contents. */ |
| 435 | if (!kmsg_dump_get_buffer(dumper, true, dst + header_size, |
| 436 | dst_size, &dump_size)) |
| 437 | break; |
| 438 | |
| 439 | if (big_oops_buf) { |
| 440 | zipped_len = pstore_compress(dst, psinfo->buf, |
| 441 | header_size + dump_size, |
| 442 | psinfo->bufsize); |
| 443 | |
| 444 | if (zipped_len > 0) { |
| 445 | record.compressed = true; |
| 446 | record.size = zipped_len; |
| 447 | } else { |
| 448 | record.size = copy_kmsg_to_buffer(header_size, |
| 449 | dump_size); |
| 450 | } |
| 451 | } else { |
| 452 | record.size = header_size + dump_size; |
| 453 | } |
| 454 | |
| 455 | ret = psinfo->write(&record); |
| 456 | if (ret == 0 && reason == KMSG_DUMP_OOPS) { |
| 457 | pstore_new_entry = 1; |
| 458 | pstore_timer_kick(); |
| 459 | } |
| 460 | |
| 461 | total += record.size; |
| 462 | part++; |
| 463 | } |
| 464 | |
| 465 | up(&psinfo->buf_lock); |
| 466 | } |
| 467 | |
| 468 | static struct kmsg_dumper pstore_dumper = { |
| 469 | .dump = pstore_dump, |
| 470 | }; |
| 471 | |
| 472 | /* |
| 473 | * Register with kmsg_dump to save last part of console log on panic. |
| 474 | */ |
| 475 | static void pstore_register_kmsg(void) |
| 476 | { |
| 477 | kmsg_dump_register(&pstore_dumper); |
| 478 | } |
| 479 | |
| 480 | static void pstore_unregister_kmsg(void) |
| 481 | { |
| 482 | kmsg_dump_unregister(&pstore_dumper); |
| 483 | } |
| 484 | |
| 485 | #ifdef CONFIG_PSTORE_CONSOLE |
| 486 | static void pstore_console_write(struct console *con, const char *s, unsigned c) |
| 487 | { |
| 488 | struct pstore_record record; |
| 489 | |
| 490 | if (!c) |
| 491 | return; |
| 492 | |
| 493 | pstore_record_init(&record, psinfo); |
| 494 | record.type = PSTORE_TYPE_CONSOLE; |
| 495 | |
| 496 | record.buf = (char *)s; |
| 497 | record.size = c; |
| 498 | psinfo->write(&record); |
| 499 | } |
| 500 | |
| 501 | static struct console pstore_console = { |
| 502 | .write = pstore_console_write, |
| 503 | .index = -1, |
| 504 | }; |
| 505 | |
| 506 | static void pstore_register_console(void) |
| 507 | { |
| 508 | /* Show which backend is going to get console writes. */ |
| 509 | strscpy(pstore_console.name, psinfo->name, |
| 510 | sizeof(pstore_console.name)); |
| 511 | /* |
| 512 | * Always initialize flags here since prior unregister_console() |
| 513 | * calls may have changed settings (specifically CON_ENABLED). |
| 514 | */ |
| 515 | pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME; |
| 516 | register_console(&pstore_console); |
| 517 | } |
| 518 | |
| 519 | static void pstore_unregister_console(void) |
| 520 | { |
| 521 | unregister_console(&pstore_console); |
| 522 | } |
| 523 | #else |
| 524 | static void pstore_register_console(void) {} |
| 525 | static void pstore_unregister_console(void) {} |
| 526 | #endif |
| 527 | |
| 528 | static int pstore_write_user_compat(struct pstore_record *record, |
| 529 | const char __user *buf) |
| 530 | { |
| 531 | int ret = 0; |
| 532 | |
| 533 | if (record->buf) |
| 534 | return -EINVAL; |
| 535 | |
| 536 | record->buf = memdup_user(buf, record->size); |
| 537 | if (IS_ERR(record->buf)) { |
| 538 | ret = PTR_ERR(record->buf); |
| 539 | goto out; |
| 540 | } |
| 541 | |
| 542 | ret = record->psi->write(record); |
| 543 | |
| 544 | kfree(record->buf); |
| 545 | out: |
| 546 | record->buf = NULL; |
| 547 | |
| 548 | return unlikely(ret < 0) ? ret : record->size; |
| 549 | } |
| 550 | |
| 551 | /* |
| 552 | * platform specific persistent storage driver registers with |
| 553 | * us here. If pstore is already mounted, call the platform |
| 554 | * read function right away to populate the file system. If not |
| 555 | * then the pstore mount code will call us later to fill out |
| 556 | * the file system. |
| 557 | */ |
| 558 | int pstore_register(struct pstore_info *psi) |
| 559 | { |
| 560 | if (backend && strcmp(backend, psi->name)) { |
| 561 | pr_warn("ignoring unexpected backend '%s'\n", psi->name); |
| 562 | return -EPERM; |
| 563 | } |
| 564 | |
| 565 | /* Sanity check flags. */ |
| 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 | /* Check for required functions. */ |
| 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 | mutex_lock(&psinfo_lock); |
| 580 | if (psinfo) { |
| 581 | pr_warn("backend '%s' already loaded: ignoring '%s'\n", |
| 582 | psinfo->name, psi->name); |
| 583 | mutex_unlock(&psinfo_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 | |
| 593 | if (psi->flags & PSTORE_FLAGS_DMESG) |
| 594 | allocate_buf_for_compression(); |
| 595 | |
| 596 | pstore_get_records(0); |
| 597 | |
| 598 | if (psi->flags & PSTORE_FLAGS_DMESG) |
| 599 | pstore_register_kmsg(); |
| 600 | if (psi->flags & PSTORE_FLAGS_CONSOLE) |
| 601 | pstore_register_console(); |
| 602 | if (psi->flags & PSTORE_FLAGS_FTRACE) |
| 603 | pstore_register_ftrace(); |
| 604 | if (psi->flags & PSTORE_FLAGS_PMSG) |
| 605 | pstore_register_pmsg(); |
| 606 | |
| 607 | /* Start watching for new records, if desired. */ |
| 608 | pstore_timer_kick(); |
| 609 | |
| 610 | /* |
| 611 | * Update the module parameter backend, so it is visible |
| 612 | * through /sys/module/pstore/parameters/backend |
| 613 | */ |
| 614 | backend = kstrdup(psi->name, GFP_KERNEL); |
| 615 | |
| 616 | pr_info("Registered %s as persistent store backend\n", psi->name); |
| 617 | |
| 618 | mutex_unlock(&psinfo_lock); |
| 619 | return 0; |
| 620 | } |
| 621 | EXPORT_SYMBOL_GPL(pstore_register); |
| 622 | |
| 623 | void pstore_unregister(struct pstore_info *psi) |
| 624 | { |
| 625 | /* It's okay to unregister nothing. */ |
| 626 | if (!psi) |
| 627 | return; |
| 628 | |
| 629 | mutex_lock(&psinfo_lock); |
| 630 | |
| 631 | /* Only one backend can be registered at a time. */ |
| 632 | if (WARN_ON(psi != psinfo)) { |
| 633 | mutex_unlock(&psinfo_lock); |
| 634 | return; |
| 635 | } |
| 636 | |
| 637 | /* Unregister all callbacks. */ |
| 638 | if (psi->flags & PSTORE_FLAGS_PMSG) |
| 639 | pstore_unregister_pmsg(); |
| 640 | if (psi->flags & PSTORE_FLAGS_FTRACE) |
| 641 | pstore_unregister_ftrace(); |
| 642 | if (psi->flags & PSTORE_FLAGS_CONSOLE) |
| 643 | pstore_unregister_console(); |
| 644 | if (psi->flags & PSTORE_FLAGS_DMESG) |
| 645 | pstore_unregister_kmsg(); |
| 646 | |
| 647 | /* Stop timer and make sure all work has finished. */ |
| 648 | del_timer_sync(&pstore_timer); |
| 649 | flush_work(&pstore_work); |
| 650 | |
| 651 | /* Remove all backend records from filesystem tree. */ |
| 652 | pstore_put_backend_records(psi); |
| 653 | |
| 654 | free_buf_for_compression(); |
| 655 | |
| 656 | psinfo = NULL; |
| 657 | kfree(backend); |
| 658 | backend = NULL; |
| 659 | mutex_unlock(&psinfo_lock); |
| 660 | } |
| 661 | EXPORT_SYMBOL_GPL(pstore_unregister); |
| 662 | |
| 663 | static void decompress_record(struct pstore_record *record) |
| 664 | { |
| 665 | int ret; |
| 666 | int unzipped_len; |
| 667 | char *unzipped, *workspace; |
| 668 | |
| 669 | if (!record->compressed) |
| 670 | return; |
| 671 | |
| 672 | /* Only PSTORE_TYPE_DMESG support compression. */ |
| 673 | if (record->type != PSTORE_TYPE_DMESG) { |
| 674 | pr_warn("ignored compressed record type %d\n", record->type); |
| 675 | return; |
| 676 | } |
| 677 | |
| 678 | /* Missing compression buffer means compression was not initialized. */ |
| 679 | if (!big_oops_buf) { |
| 680 | pr_warn("no decompression method initialized!\n"); |
| 681 | return; |
| 682 | } |
| 683 | |
| 684 | /* Allocate enough space to hold max decompression and ECC. */ |
| 685 | unzipped_len = big_oops_buf_sz; |
| 686 | workspace = kmalloc(unzipped_len + record->ecc_notice_size, |
| 687 | GFP_KERNEL); |
| 688 | if (!workspace) |
| 689 | return; |
| 690 | |
| 691 | /* After decompression "unzipped_len" is almost certainly smaller. */ |
| 692 | ret = crypto_comp_decompress(tfm, record->buf, record->size, |
| 693 | workspace, &unzipped_len); |
| 694 | if (ret) { |
| 695 | pr_err("crypto_comp_decompress failed, ret = %d!\n", ret); |
| 696 | kfree(workspace); |
| 697 | return; |
| 698 | } |
| 699 | |
| 700 | /* Append ECC notice to decompressed buffer. */ |
| 701 | memcpy(workspace + unzipped_len, record->buf + record->size, |
| 702 | record->ecc_notice_size); |
| 703 | |
| 704 | /* Copy decompressed contents into an minimum-sized allocation. */ |
| 705 | unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size, |
| 706 | GFP_KERNEL); |
| 707 | kfree(workspace); |
| 708 | if (!unzipped) |
| 709 | return; |
| 710 | |
| 711 | /* Swap out compressed contents with decompressed contents. */ |
| 712 | kfree(record->buf); |
| 713 | record->buf = unzipped; |
| 714 | record->size = unzipped_len; |
| 715 | record->compressed = false; |
| 716 | } |
| 717 | |
| 718 | /* |
| 719 | * Read all the records from one persistent store backend. Create |
| 720 | * files in our filesystem. Don't warn about -EEXIST errors |
| 721 | * when we are re-scanning the backing store looking to add new |
| 722 | * error records. |
| 723 | */ |
| 724 | void pstore_get_backend_records(struct pstore_info *psi, |
| 725 | struct dentry *root, int quiet) |
| 726 | { |
| 727 | int failed = 0; |
| 728 | unsigned int stop_loop = 65536; |
| 729 | |
| 730 | if (!psi || !root) |
| 731 | return; |
| 732 | |
| 733 | mutex_lock(&psi->read_mutex); |
| 734 | if (psi->open && psi->open(psi)) |
| 735 | goto out; |
| 736 | |
| 737 | /* |
| 738 | * Backend callback read() allocates record.buf. decompress_record() |
| 739 | * may reallocate record.buf. On success, pstore_mkfile() will keep |
| 740 | * the record.buf, so free it only on failure. |
| 741 | */ |
| 742 | for (; stop_loop; stop_loop--) { |
| 743 | struct pstore_record *record; |
| 744 | int rc; |
| 745 | |
| 746 | record = kzalloc(sizeof(*record), GFP_KERNEL); |
| 747 | if (!record) { |
| 748 | pr_err("out of memory creating record\n"); |
| 749 | break; |
| 750 | } |
| 751 | pstore_record_init(record, psi); |
| 752 | |
| 753 | record->size = psi->read(record); |
| 754 | |
| 755 | /* No more records left in backend? */ |
| 756 | if (record->size <= 0) { |
| 757 | kfree(record); |
| 758 | break; |
| 759 | } |
| 760 | |
| 761 | decompress_record(record); |
| 762 | rc = pstore_mkfile(root, record); |
| 763 | if (rc) { |
| 764 | /* pstore_mkfile() did not take record, so free it. */ |
| 765 | kfree(record->buf); |
| 766 | kfree(record); |
| 767 | if (rc != -EEXIST || !quiet) |
| 768 | failed++; |
| 769 | } |
| 770 | } |
| 771 | if (psi->close) |
| 772 | psi->close(psi); |
| 773 | out: |
| 774 | mutex_unlock(&psi->read_mutex); |
| 775 | |
| 776 | if (failed) |
| 777 | pr_warn("failed to create %d record(s) from '%s'\n", |
| 778 | failed, psi->name); |
| 779 | if (!stop_loop) |
| 780 | pr_err("looping? Too many records seen from '%s'\n", |
| 781 | psi->name); |
| 782 | } |
| 783 | |
| 784 | static void pstore_dowork(struct work_struct *work) |
| 785 | { |
| 786 | pstore_get_records(1); |
| 787 | } |
| 788 | |
| 789 | static void pstore_timefunc(struct timer_list *unused) |
| 790 | { |
| 791 | if (pstore_new_entry) { |
| 792 | pstore_new_entry = 0; |
| 793 | schedule_work(&pstore_work); |
| 794 | } |
| 795 | |
| 796 | pstore_timer_kick(); |
| 797 | } |
| 798 | |
| 799 | static void __init pstore_choose_compression(void) |
| 800 | { |
| 801 | const struct pstore_zbackend *step; |
| 802 | |
| 803 | if (!compress) |
| 804 | return; |
| 805 | |
| 806 | for (step = zbackends; step->name; step++) { |
| 807 | if (!strcmp(compress, step->name)) { |
| 808 | zbackend = step; |
| 809 | return; |
| 810 | } |
| 811 | } |
| 812 | } |
| 813 | |
| 814 | static int __init pstore_init(void) |
| 815 | { |
| 816 | int ret; |
| 817 | |
| 818 | pstore_choose_compression(); |
| 819 | |
| 820 | /* |
| 821 | * Check if any pstore backends registered earlier but did not |
| 822 | * initialize compression because crypto was not ready. If so, |
| 823 | * initialize compression now. |
| 824 | */ |
| 825 | allocate_buf_for_compression(); |
| 826 | |
| 827 | ret = pstore_init_fs(); |
| 828 | if (ret) |
| 829 | free_buf_for_compression(); |
| 830 | |
| 831 | return ret; |
| 832 | } |
| 833 | late_initcall(pstore_init); |
| 834 | |
| 835 | static void __exit pstore_exit(void) |
| 836 | { |
| 837 | pstore_exit_fs(); |
| 838 | } |
| 839 | module_exit(pstore_exit) |
| 840 | |
| 841 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); |
| 842 | MODULE_LICENSE("GPL"); |