| 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(&pstore_timer, jiffies + msecs_to_jiffies(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(&zstream, Z_DEFAULT_COMPRESSION, Z_DEFLATED, |
| 189 | -MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY); |
| 190 | if (ret != Z_OK) |
| 191 | return -EINVAL; |
| 192 | |
| 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; |
| 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(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(zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL)); |
| 237 | if (!compress_workspace) { |
| 238 | pr_err("Failed to allocate zlib deflate workspace\n"); |
| 239 | kvfree(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(compress_workspace); |
| 254 | compress_workspace = NULL; |
| 255 | } |
| 256 | |
| 257 | kvfree(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(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 | struct kmsg_dump_detail *detail) |
| 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(detail->reason); |
| 289 | |
| 290 | if (pstore_cannot_block_path(detail->reason)) { |
| 291 | if (!raw_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 | raw_spin_lock_irqsave(&psinfo->buf_lock, flags); |
| 298 | } |
| 299 | |
| 300 | kmsg_dump_rewind(&iter); |
| 301 | |
| 302 | oopscount++; |
| 303 | while (total < kmsg_bytes) { |
| 304 | char *dst; |
| 305 | size_t dst_size; |
| 306 | int header_size; |
| 307 | int zipped_len = -1; |
| 308 | size_t dump_size; |
| 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 = detail->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(dst, dst_size, "%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, true, dst + header_size, |
| 328 | dst_size, &dump_size)) |
| 329 | break; |
| 330 | |
| 331 | if (big_oops_buf) { |
| 332 | zipped_len = pstore_compress(dst, psinfo->buf, |
| 333 | header_size + dump_size, |
| 334 | 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 && detail->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 | raw_spin_unlock_irqrestore(&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(&pstore_dumper); |
| 385 | } |
| 386 | |
| 387 | static void pstore_unregister_kmsg(void) |
| 388 | { |
| 389 | kmsg_dump_unregister(&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, 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(record->buf)) { |
| 445 | ret = PTR_ERR(record->buf); |
| 446 | goto out; |
| 447 | } |
| 448 | |
| 449 | ret = record->psi->write(record); |
| 450 | |
| 451 | kvfree(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(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(&psinfo_lock); |
| 498 | kfree(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 | raw_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(&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(&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(&pstore_timer); |
| 566 | flush_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(backend); |
| 575 | backend = NULL; |
| 576 | |
| 577 | pr_info("Unregistered %s as persistent store backend\n", psi->name); |
| 578 | mutex_unlock(&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(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(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(zstream, Z_FINISH); |
| 624 | if (ret != Z_STREAM_END) { |
| 625 | pr_err_ratelimited("zlib_inflate() failed, ret = %d!\n", ret); |
| 626 | kvfree(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(workspace, unzipped_len + record->ecc_notice_size, |
| 638 | GFP_KERNEL); |
| 639 | kvfree(workspace); |
| 640 | if (!unzipped) |
| 641 | return; |
| 642 | |
| 643 | /* Swap out compressed contents with decompressed contents. */ |
| 644 | kvfree(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(zlib_inflate_workspacesize(), |
| 668 | GFP_KERNEL); |
| 669 | zlib_inflateInit2(&zstream, -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(sizeof(*record), GFP_KERNEL); |
| 686 | if (!record) { |
| 687 | pr_err("out of memory creating record\n"); |
| 688 | break; |
| 689 | } |
| 690 | pstore_record_init(record, psi); |
| 691 | |
| 692 | record->size = psi->read(record); |
| 693 | |
| 694 | /* No more records left in backend? */ |
| 695 | if (record->size <= 0) { |
| 696 | kfree(record); |
| 697 | break; |
| 698 | } |
| 699 | |
| 700 | decompress_record(record, &zstream); |
| 701 | rc = pstore_mkfile(root, record); |
| 702 | if (rc) { |
| 703 | /* pstore_mkfile() did not take record, so free it. */ |
| 704 | kvfree(record->buf); |
| 705 | kfree(record->priv); |
| 706 | kfree(record); |
| 707 | if (rc != -EEXIST || !quiet) |
| 708 | failed++; |
| 709 | } |
| 710 | } |
| 711 | if (psi->close) |
| 712 | psi->close(psi); |
| 713 | out: |
| 714 | mutex_unlock(&psi->read_mutex); |
| 715 | |
| 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 | |
| 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(&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_DESCRIPTION("Persistent Storage - platform driver interface"); |
| 765 | MODULE_LICENSE("GPL"); |