1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright (c) International Business Machines Corp., 2006
   4 * Copyright (c) Nokia Corporation, 2006, 2007
   5 *
   6 * Author: Artem Bityutskiy (Битюцкий Артём)
   7 */
   8
   9/*
  10 * UBI input/output sub-system.
  11 *
  12 * This sub-system provides a uniform way to work with all kinds of the
  13 * underlying MTD devices. It also implements handy functions for reading and
  14 * writing UBI headers.
  15 *
  16 * We are trying to have a paranoid mindset and not to trust to what we read
  17 * from the flash media in order to be more secure and robust. So this
  18 * sub-system validates every single header it reads from the flash media.
  19 *
  20 * Some words about how the eraseblock headers are stored.
  21 *
  22 * The erase counter header is always stored at offset zero. By default, the
  23 * VID header is stored after the EC header at the closest aligned offset
  24 * (i.e. aligned to the minimum I/O unit size). Data starts next to the VID
  25 * header at the closest aligned offset. But this default layout may be
  26 * changed. For example, for different reasons (e.g., optimization) UBI may be
  27 * asked to put the VID header at further offset, and even at an unaligned
  28 * offset. Of course, if the offset of the VID header is unaligned, UBI adds
  29 * proper padding in front of it. Data offset may also be changed but it has to
  30 * be aligned.
  31 *
  32 * About minimal I/O units. In general, UBI assumes flash device model where
  33 * there is only one minimal I/O unit size. E.g., in case of NOR flash it is 1,
  34 * in case of NAND flash it is a NAND page, etc. This is reported by MTD in the
  35 * @ubi->mtd->writesize field. But as an exception, UBI admits use of another
  36 * (smaller) minimal I/O unit size for EC and VID headers to make it possible
  37 * to do different optimizations.
  38 *
  39 * This is extremely useful in case of NAND flashes which admit of several
  40 * write operations to one NAND page. In this case UBI can fit EC and VID
  41 * headers at one NAND page. Thus, UBI may use "sub-page" size as the minimal
  42 * I/O unit for the headers (the @ubi->hdrs_min_io_size field). But it still
  43 * reports NAND page size (@ubi->min_io_size) as a minimal I/O unit for the UBI
  44 * users.
  45 *
  46 * Example: some Samsung NANDs with 2KiB pages allow 4x 512-byte writes, so
  47 * although the minimal I/O unit is 2K, UBI uses 512 bytes for EC and VID
  48 * headers.
  49 *
  50 * Q: why not just to treat sub-page as a minimal I/O unit of this flash
  51 * device, e.g., make @ubi->min_io_size = 512 in the example above?
  52 *
  53 * A: because when writing a sub-page, MTD still writes a full 2K page but the
  54 * bytes which are not relevant to the sub-page are 0xFF. So, basically,
  55 * writing 4x512 sub-pages is 4 times slower than writing one 2KiB NAND page.
  56 * Thus, we prefer to use sub-pages only for EC and VID headers.
  57 *
  58 * As it was noted above, the VID header may start at a non-aligned offset.
  59 * For example, in case of a 2KiB page NAND flash with a 512 bytes sub-page,
  60 * the VID header may reside at offset 1984 which is the last 64 bytes of the
  61 * last sub-page (EC header is always at offset zero). This causes some
  62 * difficulties when reading and writing VID headers.
  63 *
  64 * Suppose we have a 64-byte buffer and we read a VID header at it. We change
  65 * the data and want to write this VID header out. As we can only write in
  66 * 512-byte chunks, we have to allocate one more buffer and copy our VID header
  67 * to offset 448 of this buffer.
  68 *
  69 * The I/O sub-system does the following trick in order to avoid this extra
  70 * copy. It always allocates a @ubi->vid_hdr_alsize bytes buffer for the VID
  71 * header and returns a pointer to offset @ubi->vid_hdr_shift of this buffer.
  72 * When the VID header is being written out, it shifts the VID header pointer
  73 * back and writes the whole sub-page.
  74 */
  75
  76#include <linux/crc32.h>
  77#include <linux/err.h>
  78#include <linux/slab.h>
  79#include "ubi.h"
  80
  81static int self_check_not_bad(const struct ubi_device *ubi, int pnum);
  82static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
  83static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
  84			     const struct ubi_ec_hdr *ec_hdr);
  85static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
  86static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
  87			      const struct ubi_vid_hdr *vid_hdr);
  88static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
  89			    int offset, int len);
  90
  91/**
  92 * ubi_io_read - read data from a physical eraseblock.
  93 * @ubi: UBI device description object
  94 * @buf: buffer where to store the read data
  95 * @pnum: physical eraseblock number to read from
  96 * @offset: offset within the physical eraseblock from where to read
  97 * @len: how many bytes to read
  98 *
  99 * This function reads data from offset @offset of physical eraseblock @pnum
 100 * and stores the read data in the @buf buffer. The following return codes are
 101 * possible:
 102 *
 103 * o %0 if all the requested data were successfully read;
 104 * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
 105 *   correctable bit-flips were detected; this is harmless but may indicate
 106 *   that this eraseblock may become bad soon (but do not have to);
 107 * o %-EBADMSG if the MTD subsystem reported about data integrity problems, for
 108 *   example it can be an ECC error in case of NAND; this most probably means
 109 *   that the data is corrupted;
 110 * o %-EIO if some I/O error occurred;
 111 * o other negative error codes in case of other errors.
 112 */
 113int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 114		int len)
 115{
 116	int err, retries = 0;
 117	size_t read;
 118	loff_t addr;
 119
 120	dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
 121
 122	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 123	ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 124	ubi_assert(len > 0);
 125
 126	err = self_check_not_bad(ubi, pnum);
 127	if (err)
 128		return err;
 129
 130	/*
 131	 * Deliberately corrupt the buffer to improve robustness. Indeed, if we
 132	 * do not do this, the following may happen:
 133	 * 1. The buffer contains data from previous operation, e.g., read from
 134	 *    another PEB previously. The data looks like expected, e.g., if we
 135	 *    just do not read anything and return - the caller would not
 136	 *    notice this. E.g., if we are reading a VID header, the buffer may
 137	 *    contain a valid VID header from another PEB.
 138	 * 2. The driver is buggy and returns us success or -EBADMSG or
 139	 *    -EUCLEAN, but it does not actually put any data to the buffer.
 140	 *
 141	 * This may confuse UBI or upper layers - they may think the buffer
 142	 * contains valid data while in fact it is just old data. This is
 143	 * especially possible because UBI (and UBIFS) relies on CRC, and
 144	 * treats data as correct even in case of ECC errors if the CRC is
 145	 * correct.
 146	 *
 147	 * Try to prevent this situation by changing the first byte of the
 148	 * buffer.
 149	 */
 150	*((uint8_t *)buf) ^= 0xFF;
 151
 152	addr = (loff_t)pnum * ubi->peb_size + offset;
 153retry:
 154	err = mtd_read(ubi->mtd, addr, len, &read, buf);
 155	if (err) {
 156		const char *errstr = mtd_is_eccerr(err) ? " (ECC error)" : "";
 157
 158		if (mtd_is_bitflip(err)) {
 159			/*
 160			 * -EUCLEAN is reported if there was a bit-flip which
 161			 * was corrected, so this is harmless.
 162			 *
 163			 * We do not report about it here unless debugging is
 164			 * enabled. A corresponding message will be printed
 165			 * later, when it is has been scrubbed.
 166			 */
 167			ubi_msg(ubi, "fixable bit-flip detected at PEB %d",
 168				pnum);
 169			ubi_assert(len == read);
 170			return UBI_IO_BITFLIPS;
 171		}
 172
 173		if (retries++ < UBI_IO_RETRIES) {
 174			ubi_warn(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read only %zd bytes, retry",
 175				 err, errstr, len, pnum, offset, read);
 176			yield();
 177			goto retry;
 178		}
 179
 180		ubi_err(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read %zd bytes",
 181			err, errstr, len, pnum, offset, read);
 182		dump_stack();
 183
 184		/*
 185		 * The driver should never return -EBADMSG if it failed to read
 186		 * all the requested data. But some buggy drivers might do
 187		 * this, so we change it to -EIO.
 188		 */
 189		if (read != len && mtd_is_eccerr(err)) {
 190			ubi_assert(0);
 191			err = -EIO;
 192		}
 193	} else {
 194		ubi_assert(len == read);
 195
 196		if (ubi_dbg_is_bitflip(ubi)) {
 197			dbg_gen("bit-flip (emulated)");
 198			err = UBI_IO_BITFLIPS;
 199		}
 200	}
 201
 202	return err;
 203}
 204
 205/**
 206 * ubi_io_write - write data to a physical eraseblock.
 207 * @ubi: UBI device description object
 208 * @buf: buffer with the data to write
 209 * @pnum: physical eraseblock number to write to
 210 * @offset: offset within the physical eraseblock where to write
 211 * @len: how many bytes to write
 212 *
 213 * This function writes @len bytes of data from buffer @buf to offset @offset
 214 * of physical eraseblock @pnum. If all the data were successfully written,
 215 * zero is returned. If an error occurred, this function returns a negative
 216 * error code. If %-EIO is returned, the physical eraseblock most probably went
 217 * bad.
 218 *
 219 * Note, in case of an error, it is possible that something was still written
 220 * to the flash media, but may be some garbage.
 221 */
 222int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 223		 int len)
 224{
 225	int err;
 226	size_t written;
 227	loff_t addr;
 228
 229	dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 230
 231	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 232	ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 233	ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 234	ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 235
 236	if (ubi->ro_mode) {
 237		ubi_err(ubi, "read-only mode");
 238		return -EROFS;
 239	}
 240
 241	err = self_check_not_bad(ubi, pnum);
 242	if (err)
 243		return err;
 244
 245	/* The area we are writing to has to contain all 0xFF bytes */
 246	err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 247	if (err)
 248		return err;
 249
 250	if (offset >= ubi->leb_start) {
 251		/*
 252		 * We write to the data area of the physical eraseblock. Make
 253		 * sure it has valid EC and VID headers.
 254		 */
 255		err = self_check_peb_ec_hdr(ubi, pnum);
 256		if (err)
 257			return err;
 258		err = self_check_peb_vid_hdr(ubi, pnum);
 259		if (err)
 260			return err;
 261	}
 262
 263	if (ubi_dbg_is_write_failure(ubi)) {
 264		ubi_err(ubi, "cannot write %d bytes to PEB %d:%d (emulated)",
 265			len, pnum, offset);
 266		dump_stack();
 267		return -EIO;
 268	}
 269
 270	addr = (loff_t)pnum * ubi->peb_size + offset;
 271	err = mtd_write(ubi->mtd, addr, len, &written, buf);
 272	if (err) {
 273		ubi_err(ubi, "error %d while writing %d bytes to PEB %d:%d, written %zd bytes",
 274			err, len, pnum, offset, written);
 275		dump_stack();
 276		ubi_dump_flash(ubi, pnum, offset, len);
 277	} else
 278		ubi_assert(written == len);
 279
 280	if (!err) {
 281		err = self_check_write(ubi, buf, pnum, offset, len);
 282		if (err)
 283			return err;
 284
 285		/*
 286		 * Since we always write sequentially, the rest of the PEB has
 287		 * to contain only 0xFF bytes.
 288		 */
 289		offset += len;
 290		len = ubi->peb_size - offset;
 291		if (len)
 292			err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 293	}
 294
 295	return err;
 296}
 297
 298/**
 299 * do_sync_erase - synchronously erase a physical eraseblock.
 300 * @ubi: UBI device description object
 301 * @pnum: the physical eraseblock number to erase
 302 *
 303 * This function synchronously erases physical eraseblock @pnum and returns
 304 * zero in case of success and a negative error code in case of failure. If
 305 * %-EIO is returned, the physical eraseblock most probably went bad.
 306 */
 307static int do_sync_erase(struct ubi_device *ubi, int pnum)
 308{
 309	int err, retries = 0;
 310	struct erase_info ei;
 311
 312	dbg_io("erase PEB %d", pnum);
 313	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 314
 315	if (ubi->ro_mode) {
 316		ubi_err(ubi, "read-only mode");
 317		return -EROFS;
 318	}
 319
 320retry:
 321	memset(&ei, 0, sizeof(struct erase_info));
 322
 323	ei.addr     = (loff_t)pnum * ubi->peb_size;
 324	ei.len      = ubi->peb_size;
 325
 326	err = mtd_erase(ubi->mtd, &ei);
 327	if (err) {
 328		if (retries++ < UBI_IO_RETRIES) {
 329			ubi_warn(ubi, "error %d while erasing PEB %d, retry",
 330				 err, pnum);
 331			yield();
 332			goto retry;
 333		}
 334		ubi_err(ubi, "cannot erase PEB %d, error %d", pnum, err);
 335		dump_stack();
 336		return err;
 337	}
 338
 339	err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 340	if (err)
 341		return err;
 342
 343	if (ubi_dbg_is_erase_failure(ubi)) {
 344		ubi_err(ubi, "cannot erase PEB %d (emulated)", pnum);
 345		return -EIO;
 346	}
 347
 348	return 0;
 349}
 350
 351/* Patterns to write to a physical eraseblock when torturing it */
 352static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 353
 354/**
 355 * torture_peb - test a supposedly bad physical eraseblock.
 356 * @ubi: UBI device description object
 357 * @pnum: the physical eraseblock number to test
 358 *
 359 * This function returns %-EIO if the physical eraseblock did not pass the
 360 * test, a positive number of erase operations done if the test was
 361 * successfully passed, and other negative error codes in case of other errors.
 362 */
 363static int torture_peb(struct ubi_device *ubi, int pnum)
 364{
 365	int err, i, patt_count;
 366
 367	ubi_msg(ubi, "run torture test for PEB %d", pnum);
 368	patt_count = ARRAY_SIZE(patterns);
 369	ubi_assert(patt_count > 0);
 370
 371	mutex_lock(&ubi->buf_mutex);
 372	for (i = 0; i < patt_count; i++) {
 373		err = do_sync_erase(ubi, pnum);
 374		if (err)
 375			goto out;
 376
 377		/* Make sure the PEB contains only 0xFF bytes */
 378		err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 379		if (err)
 380			goto out;
 381
 382		err = ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->peb_size);
 383		if (err == 0) {
 384			ubi_err(ubi, "erased PEB %d, but a non-0xFF byte found",
 385				pnum);
 386			err = -EIO;
 387			goto out;
 388		}
 389
 390		/* Write a pattern and check it */
 391		memset(ubi->peb_buf, patterns[i], ubi->peb_size);
 392		err = ubi_io_write(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 393		if (err)
 394			goto out;
 395
 396		memset(ubi->peb_buf, ~patterns[i], ubi->peb_size);
 397		err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 398		if (err)
 399			goto out;
 400
 401		err = ubi_check_pattern(ubi->peb_buf, patterns[i],
 402					ubi->peb_size);
 403		if (err == 0) {
 404			ubi_err(ubi, "pattern %x checking failed for PEB %d",
 405				patterns[i], pnum);
 406			err = -EIO;
 407			goto out;
 408		}
 409	}
 410
 411	err = patt_count;
 412	ubi_msg(ubi, "PEB %d passed torture test, do not mark it as bad", pnum);
 413
 414out:
 415	mutex_unlock(&ubi->buf_mutex);
 416	if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
 417		/*
 418		 * If a bit-flip or data integrity error was detected, the test
 419		 * has not passed because it happened on a freshly erased
 420		 * physical eraseblock which means something is wrong with it.
 421		 */
 422		ubi_err(ubi, "read problems on freshly erased PEB %d, must be bad",
 423			pnum);
 424		err = -EIO;
 425	}
 426	return err;
 427}
 428
 429/**
 430 * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 431 * @ubi: UBI device description object
 432 * @pnum: physical eraseblock number to prepare
 433 *
 434 * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 435 * algorithm: the PEB is first filled with zeroes, then it is erased. And
 436 * filling with zeroes starts from the end of the PEB. This was observed with
 437 * Spansion S29GL512N NOR flash.
 438 *
 439 * This means that in case of a power cut we may end up with intact data at the
 440 * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 441 * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 442 * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 443 * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 444 *
 445 * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 446 * magic numbers in order to invalidate them and prevent the failures. Returns
 447 * zero in case of success and a negative error code in case of failure.
 448 */
 449static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 450{
 451	int err;
 452	size_t written;
 453	loff_t addr;
 454	uint32_t data = 0;
 455	struct ubi_ec_hdr ec_hdr;
 456	struct ubi_vid_io_buf vidb;
 457
 458	/*
 459	 * Note, we cannot generally define VID header buffers on stack,
 460	 * because of the way we deal with these buffers (see the header
 461	 * comment in this file). But we know this is a NOR-specific piece of
 462	 * code, so we can do this. But yes, this is error-prone and we should
 463	 * (pre-)allocate VID header buffer instead.
 464	 */
 465	struct ubi_vid_hdr vid_hdr;
 466
 467	/*
 468	 * If VID or EC is valid, we have to corrupt them before erasing.
 469	 * It is important to first invalidate the EC header, and then the VID
 470	 * header. Otherwise a power cut may lead to valid EC header and
 471	 * invalid VID header, in which case UBI will treat this PEB as
 472	 * corrupted and will try to preserve it, and print scary warnings.
 473	 */
 474	addr = (loff_t)pnum * ubi->peb_size;
 475	err = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
 476	if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 477	    err != UBI_IO_FF){
 478		err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 479		if(err)
 480			goto error;
 481	}
 482
 483	ubi_init_vid_buf(ubi, &vidb, &vid_hdr);
 484	ubi_assert(&vid_hdr == ubi_get_vid_hdr(&vidb));
 485
 486	err = ubi_io_read_vid_hdr(ubi, pnum, &vidb, 0);
 487	if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 488	    err != UBI_IO_FF){
 489		addr += ubi->vid_hdr_aloffset;
 490		err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 491		if (err)
 492			goto error;
 493	}
 494	return 0;
 495
 496error:
 497	/*
 498	 * The PEB contains a valid VID or EC header, but we cannot invalidate
 499	 * it. Supposedly the flash media or the driver is screwed up, so
 500	 * return an error.
 501	 */
 502	ubi_err(ubi, "cannot invalidate PEB %d, write returned %d", pnum, err);
 503	ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
 504	return -EIO;
 505}
 506
 507/**
 508 * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 509 * @ubi: UBI device description object
 510 * @pnum: physical eraseblock number to erase
 511 * @torture: if this physical eraseblock has to be tortured
 512 *
 513 * This function synchronously erases physical eraseblock @pnum. If @torture
 514 * flag is not zero, the physical eraseblock is checked by means of writing
 515 * different patterns to it and reading them back. If the torturing is enabled,
 516 * the physical eraseblock is erased more than once.
 517 *
 518 * This function returns the number of erasures made in case of success, %-EIO
 519 * if the erasure failed or the torturing test failed, and other negative error
 520 * codes in case of other errors. Note, %-EIO means that the physical
 521 * eraseblock is bad.
 522 */
 523int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 524{
 525	int err, ret = 0;
 526
 527	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 528
 529	err = self_check_not_bad(ubi, pnum);
 530	if (err != 0)
 531		return err;
 532
 533	if (ubi->ro_mode) {
 534		ubi_err(ubi, "read-only mode");
 535		return -EROFS;
 536	}
 537
 538	/*
 539	 * If the flash is ECC-ed then we have to erase the ECC block before we
 540	 * can write to it. But the write is in preparation to an erase in the
 541	 * first place. This means we cannot zero out EC and VID before the
 542	 * erase and we just have to hope the flash starts erasing from the
 543	 * start of the page.
 544	 */
 545	if (ubi->nor_flash && ubi->mtd->writesize == 1) {
 546		err = nor_erase_prepare(ubi, pnum);
 547		if (err)
 548			return err;
 549	}
 550
 551	if (torture) {
 552		ret = torture_peb(ubi, pnum);
 553		if (ret < 0)
 554			return ret;
 555	}
 556
 557	err = do_sync_erase(ubi, pnum);
 558	if (err)
 559		return err;
 560
 561	return ret + 1;
 562}
 563
 564/**
 565 * ubi_io_is_bad - check if a physical eraseblock is bad.
 566 * @ubi: UBI device description object
 567 * @pnum: the physical eraseblock number to check
 568 *
 569 * This function returns a positive number if the physical eraseblock is bad,
 570 * zero if not, and a negative error code if an error occurred.
 571 */
 572int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 573{
 574	struct mtd_info *mtd = ubi->mtd;
 575
 576	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 577
 578	if (ubi->bad_allowed) {
 579		int ret;
 580
 581		ret = mtd_block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 582		if (ret < 0)
 583			ubi_err(ubi, "error %d while checking if PEB %d is bad",
 584				ret, pnum);
 585		else if (ret)
 586			dbg_io("PEB %d is bad", pnum);
 587		return ret;
 588	}
 589
 590	return 0;
 591}
 592
 593/**
 594 * ubi_io_mark_bad - mark a physical eraseblock as bad.
 595 * @ubi: UBI device description object
 596 * @pnum: the physical eraseblock number to mark
 597 *
 598 * This function returns zero in case of success and a negative error code in
 599 * case of failure.
 600 */
 601int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 602{
 603	int err;
 604	struct mtd_info *mtd = ubi->mtd;
 605
 606	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 607
 608	if (ubi->ro_mode) {
 609		ubi_err(ubi, "read-only mode");
 610		return -EROFS;
 611	}
 612
 613	if (!ubi->bad_allowed)
 614		return 0;
 615
 616	err = mtd_block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 617	if (err)
 618		ubi_err(ubi, "cannot mark PEB %d bad, error %d", pnum, err);
 619	return err;
 620}
 621
 622/**
 623 * validate_ec_hdr - validate an erase counter header.
 624 * @ubi: UBI device description object
 625 * @ec_hdr: the erase counter header to check
 626 *
 627 * This function returns zero if the erase counter header is OK, and %1 if
 628 * not.
 629 */
 630static int validate_ec_hdr(const struct ubi_device *ubi,
 631			   const struct ubi_ec_hdr *ec_hdr)
 632{
 633	long long ec;
 634	int vid_hdr_offset, leb_start;
 635
 636	ec = be64_to_cpu(ec_hdr->ec);
 637	vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 638	leb_start = be32_to_cpu(ec_hdr->data_offset);
 639
 640	if (ec_hdr->version != UBI_VERSION) {
 641		ubi_err(ubi, "node with incompatible UBI version found: this UBI version is %d, image version is %d",
 642			UBI_VERSION, (int)ec_hdr->version);
 643		goto bad;
 644	}
 645
 646	if (vid_hdr_offset != ubi->vid_hdr_offset) {
 647		ubi_err(ubi, "bad VID header offset %d, expected %d",
 648			vid_hdr_offset, ubi->vid_hdr_offset);
 649		goto bad;
 650	}
 651
 652	if (leb_start != ubi->leb_start) {
 653		ubi_err(ubi, "bad data offset %d, expected %d",
 654			leb_start, ubi->leb_start);
 655		goto bad;
 656	}
 657
 658	if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 659		ubi_err(ubi, "bad erase counter %lld", ec);
 660		goto bad;
 661	}
 662
 663	return 0;
 664
 665bad:
 666	ubi_err(ubi, "bad EC header");
 667	ubi_dump_ec_hdr(ec_hdr);
 668	dump_stack();
 669	return 1;
 670}
 671
 672/**
 673 * ubi_io_read_ec_hdr - read and check an erase counter header.
 674 * @ubi: UBI device description object
 675 * @pnum: physical eraseblock to read from
 676 * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 677 * header
 678 * @verbose: be verbose if the header is corrupted or was not found
 679 *
 680 * This function reads erase counter header from physical eraseblock @pnum and
 681 * stores it in @ec_hdr. This function also checks CRC checksum of the read
 682 * erase counter header. The following codes may be returned:
 683 *
 684 * o %0 if the CRC checksum is correct and the header was successfully read;
 685 * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 686 *   and corrected by the flash driver; this is harmless but may indicate that
 687 *   this eraseblock may become bad soon (but may be not);
 688 * o %UBI_IO_BAD_HDR if the erase counter header is corrupted (a CRC error);
 689 * o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
 690 *   a data integrity error (uncorrectable ECC error in case of NAND);
 691 * o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly empty)
 692 * o a negative error code in case of failure.
 693 */
 694int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 695		       struct ubi_ec_hdr *ec_hdr, int verbose)
 696{
 697	int err, read_err;
 698	uint32_t crc, magic, hdr_crc;
 699
 700	dbg_io("read EC header from PEB %d", pnum);
 701	ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 702
 703	read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 704	if (read_err) {
 705		if (read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 706			return read_err;
 707
 708		/*
 709		 * We read all the data, but either a correctable bit-flip
 710		 * occurred, or MTD reported a data integrity error
 711		 * (uncorrectable ECC error in case of NAND). The former is
 712		 * harmless, the later may mean that the read data is
 713		 * corrupted. But we have a CRC check-sum and we will detect
 714		 * this. If the EC header is still OK, we just report this as
 715		 * there was a bit-flip, to force scrubbing.
 716		 */
 717	}
 718
 719	magic = be32_to_cpu(ec_hdr->magic);
 720	if (magic != UBI_EC_HDR_MAGIC) {
 721		if (mtd_is_eccerr(read_err))
 722			return UBI_IO_BAD_HDR_EBADMSG;
 723
 724		/*
 725		 * The magic field is wrong. Let's check if we have read all
 726		 * 0xFF. If yes, this physical eraseblock is assumed to be
 727		 * empty.
 728		 */
 729		if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 730			/* The physical eraseblock is supposedly empty */
 731			if (verbose)
 732				ubi_warn(ubi, "no EC header found at PEB %d, only 0xFF bytes",
 733					 pnum);
 734			dbg_bld("no EC header found at PEB %d, only 0xFF bytes",
 735				pnum);
 736			if (!read_err)
 737				return UBI_IO_FF;
 738			else
 739				return UBI_IO_FF_BITFLIPS;
 740		}
 741
 742		/*
 743		 * This is not a valid erase counter header, and these are not
 744		 * 0xFF bytes. Report that the header is corrupted.
 745		 */
 746		if (verbose) {
 747			ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
 748				 pnum, magic, UBI_EC_HDR_MAGIC);
 749			ubi_dump_ec_hdr(ec_hdr);
 750		}
 751		dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
 752			pnum, magic, UBI_EC_HDR_MAGIC);
 753		return UBI_IO_BAD_HDR;
 754	}
 755
 756	crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 757	hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 758
 759	if (hdr_crc != crc) {
 760		if (verbose) {
 761			ubi_warn(ubi, "bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 762				 pnum, crc, hdr_crc);
 763			ubi_dump_ec_hdr(ec_hdr);
 764		}
 765		dbg_bld("bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 766			pnum, crc, hdr_crc);
 767
 768		if (!read_err)
 769			return UBI_IO_BAD_HDR;
 770		else
 771			return UBI_IO_BAD_HDR_EBADMSG;
 772	}
 773
 774	/* And of course validate what has just been read from the media */
 775	err = validate_ec_hdr(ubi, ec_hdr);
 776	if (err) {
 777		ubi_err(ubi, "validation failed for PEB %d", pnum);
 778		return -EINVAL;
 779	}
 780
 781	/*
 782	 * If there was %-EBADMSG, but the header CRC is still OK, report about
 783	 * a bit-flip to force scrubbing on this PEB.
 784	 */
 785	return read_err ? UBI_IO_BITFLIPS : 0;
 786}
 787
 788/**
 789 * ubi_io_write_ec_hdr - write an erase counter header.
 790 * @ubi: UBI device description object
 791 * @pnum: physical eraseblock to write to
 792 * @ec_hdr: the erase counter header to write
 793 *
 794 * This function writes erase counter header described by @ec_hdr to physical
 795 * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 796 * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 797 * field.
 798 *
 799 * This function returns zero in case of success and a negative error code in
 800 * case of failure. If %-EIO is returned, the physical eraseblock most probably
 801 * went bad.
 802 */
 803int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 804			struct ubi_ec_hdr *ec_hdr)
 805{
 806	int err;
 807	uint32_t crc;
 808
 809	dbg_io("write EC header to PEB %d", pnum);
 810	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 811
 812	ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 813	ec_hdr->version = UBI_VERSION;
 814	ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 815	ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 816	ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 817	crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 818	ec_hdr->hdr_crc = cpu_to_be32(crc);
 819
 820	err = self_check_ec_hdr(ubi, pnum, ec_hdr);
 821	if (err)
 822		return err;
 823
 824	if (ubi_dbg_power_cut(ubi, POWER_CUT_EC_WRITE))
 825		return -EROFS;
 826
 827	err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 828	return err;
 829}
 830
 831/**
 832 * validate_vid_hdr - validate a volume identifier header.
 833 * @ubi: UBI device description object
 834 * @vid_hdr: the volume identifier header to check
 835 *
 836 * This function checks that data stored in the volume identifier header
 837 * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 838 */
 839static int validate_vid_hdr(const struct ubi_device *ubi,
 840			    const struct ubi_vid_hdr *vid_hdr)
 841{
 842	int vol_type = vid_hdr->vol_type;
 843	int copy_flag = vid_hdr->copy_flag;
 844	int vol_id = be32_to_cpu(vid_hdr->vol_id);
 845	int lnum = be32_to_cpu(vid_hdr->lnum);
 846	int compat = vid_hdr->compat;
 847	int data_size = be32_to_cpu(vid_hdr->data_size);
 848	int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 849	int data_pad = be32_to_cpu(vid_hdr->data_pad);
 850	int data_crc = be32_to_cpu(vid_hdr->data_crc);
 851	int usable_leb_size = ubi->leb_size - data_pad;
 852
 853	if (copy_flag != 0 && copy_flag != 1) {
 854		ubi_err(ubi, "bad copy_flag");
 855		goto bad;
 856	}
 857
 858	if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 859	    data_pad < 0) {
 860		ubi_err(ubi, "negative values");
 861		goto bad;
 862	}
 863
 864	if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 865		ubi_err(ubi, "bad vol_id");
 866		goto bad;
 867	}
 868
 869	if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 870		ubi_err(ubi, "bad compat");
 871		goto bad;
 872	}
 873
 874	if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 875	    compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 876	    compat != UBI_COMPAT_REJECT) {
 877		ubi_err(ubi, "bad compat");
 878		goto bad;
 879	}
 880
 881	if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 882		ubi_err(ubi, "bad vol_type");
 883		goto bad;
 884	}
 885
 886	if (data_pad >= ubi->leb_size / 2) {
 887		ubi_err(ubi, "bad data_pad");
 888		goto bad;
 889	}
 890
 891	if (data_size > ubi->leb_size) {
 892		ubi_err(ubi, "bad data_size");
 893		goto bad;
 894	}
 895
 896	if (vol_type == UBI_VID_STATIC) {
 897		/*
 898		 * Although from high-level point of view static volumes may
 899		 * contain zero bytes of data, but no VID headers can contain
 900		 * zero at these fields, because they empty volumes do not have
 901		 * mapped logical eraseblocks.
 902		 */
 903		if (used_ebs == 0) {
 904			ubi_err(ubi, "zero used_ebs");
 905			goto bad;
 906		}
 907		if (data_size == 0) {
 908			ubi_err(ubi, "zero data_size");
 909			goto bad;
 910		}
 911		if (lnum < used_ebs - 1) {
 912			if (data_size != usable_leb_size) {
 913				ubi_err(ubi, "bad data_size");
 914				goto bad;
 915			}
 916		} else if (lnum > used_ebs - 1) {
 
 
 
 
 
 917			ubi_err(ubi, "too high lnum");
 918			goto bad;
 919		}
 920	} else {
 921		if (copy_flag == 0) {
 922			if (data_crc != 0) {
 923				ubi_err(ubi, "non-zero data CRC");
 924				goto bad;
 925			}
 926			if (data_size != 0) {
 927				ubi_err(ubi, "non-zero data_size");
 928				goto bad;
 929			}
 930		} else {
 931			if (data_size == 0) {
 932				ubi_err(ubi, "zero data_size of copy");
 933				goto bad;
 934			}
 935		}
 936		if (used_ebs != 0) {
 937			ubi_err(ubi, "bad used_ebs");
 938			goto bad;
 939		}
 940	}
 941
 942	return 0;
 943
 944bad:
 945	ubi_err(ubi, "bad VID header");
 946	ubi_dump_vid_hdr(vid_hdr);
 947	dump_stack();
 948	return 1;
 949}
 950
 951/**
 952 * ubi_io_read_vid_hdr - read and check a volume identifier header.
 953 * @ubi: UBI device description object
 954 * @pnum: physical eraseblock number to read from
 955 * @vidb: the volume identifier buffer to store data in
 956 * @verbose: be verbose if the header is corrupted or wasn't found
 957 *
 958 * This function reads the volume identifier header from physical eraseblock
 959 * @pnum and stores it in @vidb. It also checks CRC checksum of the read
 960 * volume identifier header. The error codes are the same as in
 961 * 'ubi_io_read_ec_hdr()'.
 962 *
 963 * Note, the implementation of this function is also very similar to
 964 * 'ubi_io_read_ec_hdr()', so refer commentaries in 'ubi_io_read_ec_hdr()'.
 965 */
 966int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 967			struct ubi_vid_io_buf *vidb, int verbose)
 968{
 969	int err, read_err;
 970	uint32_t crc, magic, hdr_crc;
 971	struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
 972	void *p = vidb->buffer;
 973
 974	dbg_io("read VID header from PEB %d", pnum);
 975	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 976
 977	read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 978			  ubi->vid_hdr_shift + UBI_VID_HDR_SIZE);
 979	if (read_err && read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 980		return read_err;
 981
 982	magic = be32_to_cpu(vid_hdr->magic);
 983	if (magic != UBI_VID_HDR_MAGIC) {
 984		if (mtd_is_eccerr(read_err))
 985			return UBI_IO_BAD_HDR_EBADMSG;
 986
 987		if (ubi_check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
 988			if (verbose)
 989				ubi_warn(ubi, "no VID header found at PEB %d, only 0xFF bytes",
 990					 pnum);
 991			dbg_bld("no VID header found at PEB %d, only 0xFF bytes",
 992				pnum);
 993			if (!read_err)
 994				return UBI_IO_FF;
 995			else
 996				return UBI_IO_FF_BITFLIPS;
 997		}
 998
 999		if (verbose) {
1000			ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
1001				 pnum, magic, UBI_VID_HDR_MAGIC);
1002			ubi_dump_vid_hdr(vid_hdr);
1003		}
1004		dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
1005			pnum, magic, UBI_VID_HDR_MAGIC);
1006		return UBI_IO_BAD_HDR;
1007	}
1008
1009	crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1010	hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1011
1012	if (hdr_crc != crc) {
1013		if (verbose) {
1014			ubi_warn(ubi, "bad CRC at PEB %d, calculated %#08x, read %#08x",
1015				 pnum, crc, hdr_crc);
1016			ubi_dump_vid_hdr(vid_hdr);
1017		}
1018		dbg_bld("bad CRC at PEB %d, calculated %#08x, read %#08x",
1019			pnum, crc, hdr_crc);
1020		if (!read_err)
1021			return UBI_IO_BAD_HDR;
1022		else
1023			return UBI_IO_BAD_HDR_EBADMSG;
1024	}
1025
1026	err = validate_vid_hdr(ubi, vid_hdr);
1027	if (err) {
1028		ubi_err(ubi, "validation failed for PEB %d", pnum);
1029		return -EINVAL;
1030	}
1031
1032	return read_err ? UBI_IO_BITFLIPS : 0;
1033}
1034
1035/**
1036 * ubi_io_write_vid_hdr - write a volume identifier header.
1037 * @ubi: UBI device description object
1038 * @pnum: the physical eraseblock number to write to
1039 * @vidb: the volume identifier buffer to write
1040 *
1041 * This function writes the volume identifier header described by @vid_hdr to
1042 * physical eraseblock @pnum. This function automatically fills the
1043 * @vidb->hdr->magic and the @vidb->hdr->version fields, as well as calculates
1044 * header CRC checksum and stores it at vidb->hdr->hdr_crc.
1045 *
1046 * This function returns zero in case of success and a negative error code in
1047 * case of failure. If %-EIO is returned, the physical eraseblock probably went
1048 * bad.
1049 */
1050int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1051			 struct ubi_vid_io_buf *vidb)
1052{
1053	struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
1054	int err;
1055	uint32_t crc;
1056	void *p = vidb->buffer;
1057
1058	dbg_io("write VID header to PEB %d", pnum);
1059	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1060
1061	err = self_check_peb_ec_hdr(ubi, pnum);
1062	if (err)
1063		return err;
1064
1065	vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1066	vid_hdr->version = UBI_VERSION;
1067	crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1068	vid_hdr->hdr_crc = cpu_to_be32(crc);
1069
1070	err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1071	if (err)
1072		return err;
1073
1074	if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
1075		return -EROFS;
1076
1077	err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1078			   ubi->vid_hdr_alsize);
1079	return err;
1080}
1081
1082/**
1083 * self_check_not_bad - ensure that a physical eraseblock is not bad.
1084 * @ubi: UBI device description object
1085 * @pnum: physical eraseblock number to check
1086 *
1087 * This function returns zero if the physical eraseblock is good, %-EINVAL if
1088 * it is bad and a negative error code if an error occurred.
1089 */
1090static int self_check_not_bad(const struct ubi_device *ubi, int pnum)
1091{
1092	int err;
1093
1094	if (!ubi_dbg_chk_io(ubi))
1095		return 0;
1096
1097	err = ubi_io_is_bad(ubi, pnum);
1098	if (!err)
1099		return err;
1100
1101	ubi_err(ubi, "self-check failed for PEB %d", pnum);
1102	dump_stack();
1103	return err > 0 ? -EINVAL : err;
1104}
1105
1106/**
1107 * self_check_ec_hdr - check if an erase counter header is all right.
1108 * @ubi: UBI device description object
1109 * @pnum: physical eraseblock number the erase counter header belongs to
1110 * @ec_hdr: the erase counter header to check
1111 *
1112 * This function returns zero if the erase counter header contains valid
1113 * values, and %-EINVAL if not.
1114 */
1115static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1116			     const struct ubi_ec_hdr *ec_hdr)
1117{
1118	int err;
1119	uint32_t magic;
1120
1121	if (!ubi_dbg_chk_io(ubi))
1122		return 0;
1123
1124	magic = be32_to_cpu(ec_hdr->magic);
1125	if (magic != UBI_EC_HDR_MAGIC) {
1126		ubi_err(ubi, "bad magic %#08x, must be %#08x",
1127			magic, UBI_EC_HDR_MAGIC);
1128		goto fail;
1129	}
1130
1131	err = validate_ec_hdr(ubi, ec_hdr);
1132	if (err) {
1133		ubi_err(ubi, "self-check failed for PEB %d", pnum);
1134		goto fail;
1135	}
1136
1137	return 0;
1138
1139fail:
1140	ubi_dump_ec_hdr(ec_hdr);
1141	dump_stack();
1142	return -EINVAL;
1143}
1144
1145/**
1146 * self_check_peb_ec_hdr - check erase counter header.
1147 * @ubi: UBI device description object
1148 * @pnum: the physical eraseblock number to check
1149 *
1150 * This function returns zero if the erase counter header is all right and
1151 * a negative error code if not or if an error occurred.
1152 */
1153static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1154{
1155	int err;
1156	uint32_t crc, hdr_crc;
1157	struct ubi_ec_hdr *ec_hdr;
1158
1159	if (!ubi_dbg_chk_io(ubi))
1160		return 0;
1161
1162	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1163	if (!ec_hdr)
1164		return -ENOMEM;
1165
1166	err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1167	if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1168		goto exit;
1169
1170	crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1171	hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1172	if (hdr_crc != crc) {
1173		ubi_err(ubi, "bad CRC, calculated %#08x, read %#08x",
1174			crc, hdr_crc);
1175		ubi_err(ubi, "self-check failed for PEB %d", pnum);
1176		ubi_dump_ec_hdr(ec_hdr);
1177		dump_stack();
1178		err = -EINVAL;
1179		goto exit;
1180	}
1181
1182	err = self_check_ec_hdr(ubi, pnum, ec_hdr);
1183
1184exit:
1185	kfree(ec_hdr);
1186	return err;
1187}
1188
1189/**
1190 * self_check_vid_hdr - check that a volume identifier header is all right.
1191 * @ubi: UBI device description object
1192 * @pnum: physical eraseblock number the volume identifier header belongs to
1193 * @vid_hdr: the volume identifier header to check
1194 *
1195 * This function returns zero if the volume identifier header is all right, and
1196 * %-EINVAL if not.
1197 */
1198static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1199			      const struct ubi_vid_hdr *vid_hdr)
1200{
1201	int err;
1202	uint32_t magic;
1203
1204	if (!ubi_dbg_chk_io(ubi))
1205		return 0;
1206
1207	magic = be32_to_cpu(vid_hdr->magic);
1208	if (magic != UBI_VID_HDR_MAGIC) {
1209		ubi_err(ubi, "bad VID header magic %#08x at PEB %d, must be %#08x",
1210			magic, pnum, UBI_VID_HDR_MAGIC);
1211		goto fail;
1212	}
1213
1214	err = validate_vid_hdr(ubi, vid_hdr);
1215	if (err) {
1216		ubi_err(ubi, "self-check failed for PEB %d", pnum);
1217		goto fail;
1218	}
1219
1220	return err;
1221
1222fail:
1223	ubi_err(ubi, "self-check failed for PEB %d", pnum);
1224	ubi_dump_vid_hdr(vid_hdr);
1225	dump_stack();
1226	return -EINVAL;
1227
1228}
1229
1230/**
1231 * self_check_peb_vid_hdr - check volume identifier header.
1232 * @ubi: UBI device description object
1233 * @pnum: the physical eraseblock number to check
1234 *
1235 * This function returns zero if the volume identifier header is all right,
1236 * and a negative error code if not or if an error occurred.
1237 */
1238static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1239{
1240	int err;
1241	uint32_t crc, hdr_crc;
1242	struct ubi_vid_io_buf *vidb;
1243	struct ubi_vid_hdr *vid_hdr;
1244	void *p;
1245
1246	if (!ubi_dbg_chk_io(ubi))
1247		return 0;
1248
1249	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1250	if (!vidb)
1251		return -ENOMEM;
1252
1253	vid_hdr = ubi_get_vid_hdr(vidb);
1254	p = vidb->buffer;
1255	err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1256			  ubi->vid_hdr_alsize);
1257	if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1258		goto exit;
1259
1260	crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1261	hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1262	if (hdr_crc != crc) {
1263		ubi_err(ubi, "bad VID header CRC at PEB %d, calculated %#08x, read %#08x",
1264			pnum, crc, hdr_crc);
1265		ubi_err(ubi, "self-check failed for PEB %d", pnum);
1266		ubi_dump_vid_hdr(vid_hdr);
1267		dump_stack();
1268		err = -EINVAL;
1269		goto exit;
1270	}
1271
1272	err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1273
1274exit:
1275	ubi_free_vid_buf(vidb);
1276	return err;
1277}
1278
1279/**
1280 * self_check_write - make sure write succeeded.
1281 * @ubi: UBI device description object
1282 * @buf: buffer with data which were written
1283 * @pnum: physical eraseblock number the data were written to
1284 * @offset: offset within the physical eraseblock the data were written to
1285 * @len: how many bytes were written
1286 *
1287 * This functions reads data which were recently written and compares it with
1288 * the original data buffer - the data have to match. Returns zero if the data
1289 * match and a negative error code if not or in case of failure.
1290 */
1291static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
1292			    int offset, int len)
1293{
1294	int err, i;
1295	size_t read;
1296	void *buf1;
1297	loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1298
1299	if (!ubi_dbg_chk_io(ubi))
1300		return 0;
1301
1302	buf1 = __vmalloc(len, GFP_NOFS);
1303	if (!buf1) {
1304		ubi_err(ubi, "cannot allocate memory to check writes");
1305		return 0;
1306	}
1307
1308	err = mtd_read(ubi->mtd, addr, len, &read, buf1);
1309	if (err && !mtd_is_bitflip(err))
1310		goto out_free;
1311
1312	for (i = 0; i < len; i++) {
1313		uint8_t c = ((uint8_t *)buf)[i];
1314		uint8_t c1 = ((uint8_t *)buf1)[i];
1315		int dump_len;
1316
1317		if (c == c1)
1318			continue;
1319
1320		ubi_err(ubi, "self-check failed for PEB %d:%d, len %d",
1321			pnum, offset, len);
1322		ubi_msg(ubi, "data differ at position %d", i);
1323		dump_len = max_t(int, 128, len - i);
1324		ubi_msg(ubi, "hex dump of the original buffer from %d to %d",
1325			i, i + dump_len);
1326		print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1327			       buf + i, dump_len, 1);
1328		ubi_msg(ubi, "hex dump of the read buffer from %d to %d",
1329			i, i + dump_len);
1330		print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1331			       buf1 + i, dump_len, 1);
1332		dump_stack();
1333		err = -EINVAL;
1334		goto out_free;
1335	}
1336
1337	vfree(buf1);
1338	return 0;
1339
1340out_free:
1341	vfree(buf1);
1342	return err;
1343}
1344
1345/**
1346 * ubi_self_check_all_ff - check that a region of flash is empty.
1347 * @ubi: UBI device description object
1348 * @pnum: the physical eraseblock number to check
1349 * @offset: the starting offset within the physical eraseblock to check
1350 * @len: the length of the region to check
1351 *
1352 * This function returns zero if only 0xFF bytes are present at offset
1353 * @offset of the physical eraseblock @pnum, and a negative error code if not
1354 * or if an error occurred.
1355 */
1356int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1357{
1358	size_t read;
1359	int err;
1360	void *buf;
1361	loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1362
1363	if (!ubi_dbg_chk_io(ubi))
1364		return 0;
1365
1366	buf = __vmalloc(len, GFP_NOFS);
1367	if (!buf) {
1368		ubi_err(ubi, "cannot allocate memory to check for 0xFFs");
1369		return 0;
1370	}
1371
1372	err = mtd_read(ubi->mtd, addr, len, &read, buf);
1373	if (err && !mtd_is_bitflip(err)) {
1374		ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
1375			err, len, pnum, offset, read);
1376		goto error;
1377	}
1378
1379	err = ubi_check_pattern(buf, 0xFF, len);
1380	if (err == 0) {
1381		ubi_err(ubi, "flash region at PEB %d:%d, length %d does not contain all 0xFF bytes",
1382			pnum, offset, len);
1383		goto fail;
1384	}
1385
1386	vfree(buf);
1387	return 0;
1388
1389fail:
1390	ubi_err(ubi, "self-check failed for PEB %d", pnum);
1391	ubi_msg(ubi, "hex dump of the %d-%d region", offset, offset + len);
1392	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
1393	err = -EINVAL;
1394error:
1395	dump_stack();
1396	vfree(buf);
1397	return err;
1398}