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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 | // SPDX-License-Identifier: GPL-2.0 #define dev_fmt(fmt) "mtdoops-pstore: " fmt #include <linux/kernel.h> #include <linux/module.h> #include <linux/pstore_blk.h> #include <linux/mtd/mtd.h> #include <linux/bitops.h> #include <linux/slab.h> static struct mtdpstore_context { int index; struct pstore_blk_config info; struct pstore_device_info dev; struct mtd_info *mtd; unsigned long *rmmap; /* removed bit map */ unsigned long *usedmap; /* used bit map */ /* * used for panic write * As there are no block_isbad for panic case, we should keep this * status before panic to ensure panic_write not failed. */ unsigned long *badmap; /* bad block bit map */ } oops_cxt; static int mtdpstore_block_isbad(struct mtdpstore_context *cxt, loff_t off) { int ret; struct mtd_info *mtd = cxt->mtd; u64 blknum; off = ALIGN_DOWN(off, mtd->erasesize); blknum = div_u64(off, mtd->erasesize); if (test_bit(blknum, cxt->badmap)) return true; ret = mtd_block_isbad(mtd, off); if (ret < 0) { dev_err(&mtd->dev, "mtd_block_isbad failed, aborting\n"); return ret; } else if (ret > 0) { set_bit(blknum, cxt->badmap); return true; } return false; } static inline int mtdpstore_panic_block_isbad(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; u64 blknum; off = ALIGN_DOWN(off, mtd->erasesize); blknum = div_u64(off, mtd->erasesize); return test_bit(blknum, cxt->badmap); } static inline void mtdpstore_mark_used(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; u64 zonenum = div_u64(off, cxt->info.kmsg_size); dev_dbg(&mtd->dev, "mark zone %llu used\n", zonenum); set_bit(zonenum, cxt->usedmap); } static inline void mtdpstore_mark_unused(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; u64 zonenum = div_u64(off, cxt->info.kmsg_size); dev_dbg(&mtd->dev, "mark zone %llu unused\n", zonenum); clear_bit(zonenum, cxt->usedmap); } static inline void mtdpstore_block_mark_unused(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size; u64 zonenum; off = ALIGN_DOWN(off, mtd->erasesize); zonenum = div_u64(off, cxt->info.kmsg_size); while (zonecnt > 0) { dev_dbg(&mtd->dev, "mark zone %llu unused\n", zonenum); clear_bit(zonenum, cxt->usedmap); zonenum++; zonecnt--; } } static inline int mtdpstore_is_used(struct mtdpstore_context *cxt, loff_t off) { u64 zonenum = div_u64(off, cxt->info.kmsg_size); u64 blknum = div_u64(off, cxt->mtd->erasesize); if (test_bit(blknum, cxt->badmap)) return true; return test_bit(zonenum, cxt->usedmap); } static int mtdpstore_block_is_used(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size; u64 zonenum; off = ALIGN_DOWN(off, mtd->erasesize); zonenum = div_u64(off, cxt->info.kmsg_size); while (zonecnt > 0) { if (test_bit(zonenum, cxt->usedmap)) return true; zonenum++; zonecnt--; } return false; } static int mtdpstore_is_empty(struct mtdpstore_context *cxt, char *buf, size_t size) { struct mtd_info *mtd = cxt->mtd; size_t sz; int i; sz = min_t(uint32_t, size, mtd->writesize / 4); for (i = 0; i < sz; i++) { if (buf[i] != (char)0xFF) return false; } return true; } static void mtdpstore_mark_removed(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; u64 zonenum = div_u64(off, cxt->info.kmsg_size); dev_dbg(&mtd->dev, "mark zone %llu removed\n", zonenum); set_bit(zonenum, cxt->rmmap); } static void mtdpstore_block_clear_removed(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size; u64 zonenum; off = ALIGN_DOWN(off, mtd->erasesize); zonenum = div_u64(off, cxt->info.kmsg_size); while (zonecnt > 0) { clear_bit(zonenum, cxt->rmmap); zonenum++; zonecnt--; } } static int mtdpstore_block_is_removed(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; u32 zonecnt = mtd->erasesize / cxt->info.kmsg_size; u64 zonenum; off = ALIGN_DOWN(off, mtd->erasesize); zonenum = div_u64(off, cxt->info.kmsg_size); while (zonecnt > 0) { if (test_bit(zonenum, cxt->rmmap)) return true; zonenum++; zonecnt--; } return false; } static int mtdpstore_erase_do(struct mtdpstore_context *cxt, loff_t off) { struct mtd_info *mtd = cxt->mtd; struct erase_info erase; int ret; off = ALIGN_DOWN(off, cxt->mtd->erasesize); dev_dbg(&mtd->dev, "try to erase off 0x%llx\n", off); erase.len = cxt->mtd->erasesize; erase.addr = off; ret = mtd_erase(cxt->mtd, &erase); if (!ret) mtdpstore_block_clear_removed(cxt, off); else dev_err(&mtd->dev, "erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", (unsigned long long)erase.addr, (unsigned long long)erase.len, cxt->info.device); return ret; } /* * called while removing file * * Avoiding over erasing, do erase block only when the whole block is unused. * If the block contains valid log, do erase lazily on flush_removed() when * unregister. */ static ssize_t mtdpstore_erase(size_t size, loff_t off) { struct mtdpstore_context *cxt = &oops_cxt; if (mtdpstore_block_isbad(cxt, off)) return -EIO; mtdpstore_mark_unused(cxt, off); /* If the block still has valid data, mtdpstore do erase lazily */ if (likely(mtdpstore_block_is_used(cxt, off))) { mtdpstore_mark_removed(cxt, off); return 0; } /* all zones are unused, erase it */ return mtdpstore_erase_do(cxt, off); } /* * What is security for mtdpstore? * As there is no erase for panic case, we should ensure at least one zone * is writable. Otherwise, panic write will fail. * If zone is used, write operation will return -ENOMSG, which means that * pstore/blk will try one by one until gets an empty zone. So, it is not * needed to ensure the next zone is empty, but at least one. */ static int mtdpstore_security(struct mtdpstore_context *cxt, loff_t off) { int ret = 0, i; struct mtd_info *mtd = cxt->mtd; u32 zonenum = (u32)div_u64(off, cxt->info.kmsg_size); u32 zonecnt = (u32)div_u64(cxt->mtd->size, cxt->info.kmsg_size); u32 blkcnt = (u32)div_u64(cxt->mtd->size, cxt->mtd->erasesize); u32 erasesize = cxt->mtd->erasesize; for (i = 0; i < zonecnt; i++) { u32 num = (zonenum + i) % zonecnt; /* found empty zone */ if (!test_bit(num, cxt->usedmap)) return 0; } /* If there is no any empty zone, we have no way but to do erase */ while (blkcnt--) { div64_u64_rem(off + erasesize, cxt->mtd->size, (u64 *)&off); if (mtdpstore_block_isbad(cxt, off)) continue; ret = mtdpstore_erase_do(cxt, off); if (!ret) { mtdpstore_block_mark_unused(cxt, off); break; } } if (ret) dev_err(&mtd->dev, "all blocks bad!\n"); dev_dbg(&mtd->dev, "end security\n"); return ret; } static ssize_t mtdpstore_write(const char *buf, size_t size, loff_t off) { struct mtdpstore_context *cxt = &oops_cxt; struct mtd_info *mtd = cxt->mtd; size_t retlen; int ret; if (mtdpstore_block_isbad(cxt, off)) return -ENOMSG; /* zone is used, please try next one */ if (mtdpstore_is_used(cxt, off)) return -ENOMSG; dev_dbg(&mtd->dev, "try to write off 0x%llx size %zu\n", off, size); ret = mtd_write(cxt->mtd, off, size, &retlen, (u_char *)buf); if (ret < 0 || retlen != size) { dev_err(&mtd->dev, "write failure at %lld (%zu of %zu written), err %d\n", off, retlen, size, ret); return -EIO; } mtdpstore_mark_used(cxt, off); mtdpstore_security(cxt, off); return retlen; } static inline bool mtdpstore_is_io_error(int ret) { return ret < 0 && !mtd_is_bitflip(ret) && !mtd_is_eccerr(ret); } /* * All zones will be read as pstore/blk will read zone one by one when do * recover. */ static ssize_t mtdpstore_read(char *buf, size_t size, loff_t off) { struct mtdpstore_context *cxt = &oops_cxt; struct mtd_info *mtd = cxt->mtd; size_t retlen, done; int ret; if (mtdpstore_block_isbad(cxt, off)) return -ENOMSG; dev_dbg(&mtd->dev, "try to read off 0x%llx size %zu\n", off, size); for (done = 0, retlen = 0; done < size; done += retlen) { retlen = 0; ret = mtd_read(cxt->mtd, off + done, size - done, &retlen, (u_char *)buf + done); if (mtdpstore_is_io_error(ret)) { dev_err(&mtd->dev, "read failure at %lld (%zu of %zu read), err %d\n", off + done, retlen, size - done, ret); /* the zone may be broken, try next one */ return -ENOMSG; } /* * ECC error. The impact on log data is so small. Maybe we can * still read it and try to understand. So mtdpstore just hands * over what it gets and user can judge whether the data is * valid or not. */ if (mtd_is_eccerr(ret)) { dev_err(&mtd->dev, "ecc error at %lld (%zu of %zu read), err %d\n", off + done, retlen, size - done, ret); /* driver may not set retlen when ecc error */ retlen = retlen == 0 ? size - done : retlen; } } if (mtdpstore_is_empty(cxt, buf, size)) mtdpstore_mark_unused(cxt, off); else mtdpstore_mark_used(cxt, off); mtdpstore_security(cxt, off); return retlen; } static ssize_t mtdpstore_panic_write(const char *buf, size_t size, loff_t off) { struct mtdpstore_context *cxt = &oops_cxt; struct mtd_info *mtd = cxt->mtd; size_t retlen; int ret; if (mtdpstore_panic_block_isbad(cxt, off)) return -ENOMSG; /* zone is used, please try next one */ if (mtdpstore_is_used(cxt, off)) return -ENOMSG; ret = mtd_panic_write(cxt->mtd, off, size, &retlen, (u_char *)buf); if (ret < 0 || size != retlen) { dev_err(&mtd->dev, "panic write failure at %lld (%zu of %zu read), err %d\n", off, retlen, size, ret); return -EIO; } mtdpstore_mark_used(cxt, off); return retlen; } static void mtdpstore_notify_add(struct mtd_info *mtd) { int ret; struct mtdpstore_context *cxt = &oops_cxt; struct pstore_blk_config *info = &cxt->info; unsigned long longcnt; if (!strcmp(mtd->name, info->device)) cxt->index = mtd->index; if (mtd->index != cxt->index || cxt->index < 0) return; dev_dbg(&mtd->dev, "found matching MTD device %s\n", mtd->name); if (mtd->size < info->kmsg_size * 2) { dev_err(&mtd->dev, "MTD partition %d not big enough\n", mtd->index); return; } /* * kmsg_size must be aligned to 4096 Bytes, which is limited by * psblk. The default value of kmsg_size is 64KB. If kmsg_size * is larger than erasesize, some errors will occur since mtdpsotre * is designed on it. */ if (mtd->erasesize < info->kmsg_size) { dev_err(&mtd->dev, "eraseblock size of MTD partition %d too small\n", mtd->index); return; } if (unlikely(info->kmsg_size % mtd->writesize)) { dev_err(&mtd->dev, "record size %lu KB must align to write size %d KB\n", info->kmsg_size / 1024, mtd->writesize / 1024); return; } longcnt = BITS_TO_LONGS(div_u64(mtd->size, info->kmsg_size)); cxt->rmmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); cxt->usedmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); longcnt = BITS_TO_LONGS(div_u64(mtd->size, mtd->erasesize)); cxt->badmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL); cxt->dev.total_size = mtd->size; /* just support dmesg right now */ cxt->dev.flags = PSTORE_FLAGS_DMESG; cxt->dev.read = mtdpstore_read; cxt->dev.write = mtdpstore_write; cxt->dev.erase = mtdpstore_erase; cxt->dev.panic_write = mtdpstore_panic_write; ret = register_pstore_device(&cxt->dev); if (ret) { dev_err(&mtd->dev, "mtd%d register to psblk failed\n", mtd->index); return; } cxt->mtd = mtd; dev_info(&mtd->dev, "Attached to MTD device %d\n", mtd->index); } static int mtdpstore_flush_removed_do(struct mtdpstore_context *cxt, loff_t off, size_t size) { struct mtd_info *mtd = cxt->mtd; u_char *buf; int ret; size_t retlen; struct erase_info erase; buf = kmalloc(mtd->erasesize, GFP_KERNEL); if (!buf) return -ENOMEM; /* 1st. read to cache */ ret = mtd_read(mtd, off, mtd->erasesize, &retlen, buf); if (mtdpstore_is_io_error(ret)) goto free; /* 2nd. erase block */ erase.len = mtd->erasesize; erase.addr = off; ret = mtd_erase(mtd, &erase); if (ret) goto free; /* 3rd. write back */ while (size) { unsigned int zonesize = cxt->info.kmsg_size; /* there is valid data on block, write back */ if (mtdpstore_is_used(cxt, off)) { ret = mtd_write(mtd, off, zonesize, &retlen, buf); if (ret) dev_err(&mtd->dev, "write failure at %lld (%zu of %u written), err %d\n", off, retlen, zonesize, ret); } off += zonesize; size -= min_t(unsigned int, zonesize, size); } free: kfree(buf); return ret; } /* * What does mtdpstore_flush_removed() do? * When user remove any log file on pstore filesystem, mtdpstore should do * something to ensure log file removed. If the whole block is no longer used, * it's nice to erase the block. However if the block still contains valid log, * what mtdpstore can do is to erase and write the valid log back. */ static int mtdpstore_flush_removed(struct mtdpstore_context *cxt) { struct mtd_info *mtd = cxt->mtd; int ret; loff_t off; u32 blkcnt = (u32)div_u64(mtd->size, mtd->erasesize); for (off = 0; blkcnt > 0; blkcnt--, off += mtd->erasesize) { ret = mtdpstore_block_isbad(cxt, off); if (ret) continue; ret = mtdpstore_block_is_removed(cxt, off); if (!ret) continue; ret = mtdpstore_flush_removed_do(cxt, off, mtd->erasesize); if (ret) return ret; } return 0; } static void mtdpstore_notify_remove(struct mtd_info *mtd) { struct mtdpstore_context *cxt = &oops_cxt; if (mtd->index != cxt->index || cxt->index < 0) return; mtdpstore_flush_removed(cxt); unregister_pstore_device(&cxt->dev); kfree(cxt->badmap); kfree(cxt->usedmap); kfree(cxt->rmmap); cxt->mtd = NULL; cxt->index = -1; } static struct mtd_notifier mtdpstore_notifier = { .add = mtdpstore_notify_add, .remove = mtdpstore_notify_remove, }; static int __init mtdpstore_init(void) { int ret; struct mtdpstore_context *cxt = &oops_cxt; struct pstore_blk_config *info = &cxt->info; ret = pstore_blk_get_config(info); if (unlikely(ret)) return ret; if (strlen(info->device) == 0) { pr_err("mtd device must be supplied (device name is empty)\n"); return -EINVAL; } if (!info->kmsg_size) { pr_err("no backend enabled (kmsg_size is 0)\n"); return -EINVAL; } /* Setup the MTD device to use */ ret = kstrtoint((char *)info->device, 0, &cxt->index); if (ret) cxt->index = -1; register_mtd_user(&mtdpstore_notifier); return 0; } module_init(mtdpstore_init); static void __exit mtdpstore_exit(void) { unregister_mtd_user(&mtdpstore_notifier); } module_exit(mtdpstore_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("WeiXiong Liao <liaoweixiong@allwinnertech.com>"); MODULE_DESCRIPTION("MTD backend for pstore/blk"); |