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-rw-r--r--drivers/mtd/ubi/io.c1259
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1/*
2 * Copyright (c) International Business Machines Corp., 2006
3 * Copyright (c) Nokia Corporation, 2006, 2007
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Author: Artem Bityutskiy (Битюцкий Артём)
20 */
21
22/*
23 * UBI input/output unit.
24 *
25 * This unit provides a uniform way to work with all kinds of the underlying
26 * MTD devices. It also implements handy functions for reading and writing UBI
27 * headers.
28 *
29 * We are trying to have a paranoid mindset and not to trust to what we read
30 * from the flash media in order to be more secure and robust. So this unit
31 * validates every single header it reads from the flash media.
32 *
33 * Some words about how the eraseblock headers are stored.
34 *
35 * The erase counter header is always stored at offset zero. By default, the
36 * VID header is stored after the EC header at the closest aligned offset
37 * (i.e. aligned to the minimum I/O unit size). Data starts next to the VID
38 * header at the closest aligned offset. But this default layout may be
39 * changed. For example, for different reasons (e.g., optimization) UBI may be
40 * asked to put the VID header at further offset, and even at an unaligned
41 * offset. Of course, if the offset of the VID header is unaligned, UBI adds
42 * proper padding in front of it. Data offset may also be changed but it has to
43 * be aligned.
44 *
45 * About minimal I/O units. In general, UBI assumes flash device model where
46 * there is only one minimal I/O unit size. E.g., in case of NOR flash it is 1,
47 * in case of NAND flash it is a NAND page, etc. This is reported by MTD in the
48 * @ubi->mtd->writesize field. But as an exception, UBI admits of using another
49 * (smaller) minimal I/O unit size for EC and VID headers to make it possible
50 * to do different optimizations.
51 *
52 * This is extremely useful in case of NAND flashes which admit of several
53 * write operations to one NAND page. In this case UBI can fit EC and VID
54 * headers at one NAND page. Thus, UBI may use "sub-page" size as the minimal
55 * I/O unit for the headers (the @ubi->hdrs_min_io_size field). But it still
56 * reports NAND page size (@ubi->min_io_size) as a minimal I/O unit for the UBI
57 * users.
58 *
59 * Example: some Samsung NANDs with 2KiB pages allow 4x 512-byte writes, so
60 * although the minimal I/O unit is 2K, UBI uses 512 bytes for EC and VID
61 * headers.
62 *
63 * Q: why not just to treat sub-page as a minimal I/O unit of this flash
64 * device, e.g., make @ubi->min_io_size = 512 in the example above?
65 *
66 * A: because when writing a sub-page, MTD still writes a full 2K page but the
67 * bytes which are no relevant to the sub-page are 0xFF. So, basically, writing
68 * 4x512 sub-pages is 4 times slower then writing one 2KiB NAND page. Thus, we
69 * prefer to use sub-pages only for EV and VID headers.
70 *
71 * As it was noted above, the VID header may start at a non-aligned offset.
72 * For example, in case of a 2KiB page NAND flash with a 512 bytes sub-page,
73 * the VID header may reside at offset 1984 which is the last 64 bytes of the
74 * last sub-page (EC header is always at offset zero). This causes some
75 * difficulties when reading and writing VID headers.
76 *
77 * Suppose we have a 64-byte buffer and we read a VID header at it. We change
78 * the data and want to write this VID header out. As we can only write in
79 * 512-byte chunks, we have to allocate one more buffer and copy our VID header
80 * to offset 448 of this buffer.
81 *
82 * The I/O unit does the following trick in order to avoid this extra copy.
83 * It always allocates a @ubi->vid_hdr_alsize bytes buffer for the VID header
84 * and returns a pointer to offset @ubi->vid_hdr_shift of this buffer. When the
85 * VID header is being written out, it shifts the VID header pointer back and
86 * writes the whole sub-page.
87 */
88
89#include <linux/crc32.h>
90#include <linux/err.h>
91#include "ubi.h"
92
93#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
94static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum);
95static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
96static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
97 const struct ubi_ec_hdr *ec_hdr);
98static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
99static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
100 const struct ubi_vid_hdr *vid_hdr);
101static int paranoid_check_all_ff(const struct ubi_device *ubi, int pnum,
102 int offset, int len);
103#else
104#define paranoid_check_not_bad(ubi, pnum) 0
105#define paranoid_check_peb_ec_hdr(ubi, pnum) 0
106#define paranoid_check_ec_hdr(ubi, pnum, ec_hdr) 0
107#define paranoid_check_peb_vid_hdr(ubi, pnum) 0
108#define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0
109#define paranoid_check_all_ff(ubi, pnum, offset, len) 0
110#endif
111
112/**
113 * ubi_io_read - read data from a physical eraseblock.
114 * @ubi: UBI device description object
115 * @buf: buffer where to store the read data
116 * @pnum: physical eraseblock number to read from
117 * @offset: offset within the physical eraseblock from where to read
118 * @len: how many bytes to read
119 *
120 * This function reads data from offset @offset of physical eraseblock @pnum
121 * and stores the read data in the @buf buffer. The following return codes are
122 * possible:
123 *
124 * o %0 if all the requested data were successfully read;
125 * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
126 * correctable bit-flips were detected; this is harmless but may indicate
127 * that this eraseblock may become bad soon (but do not have to);
128 * o %-EBADMSG if the MTD subsystem reported about data data integrity
129 * problems, for example it can me an ECC error in case of NAND; this most
130 * probably means that the data is corrupted;
131 * o %-EIO if some I/O error occurred;
132 * o other negative error codes in case of other errors.
133 */
134int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
135 int len)
136{
137 int err, retries = 0;
138 size_t read;
139 loff_t addr;
140
141 dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
142
143 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
144 ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
145 ubi_assert(len > 0);
146
147 err = paranoid_check_not_bad(ubi, pnum);
148 if (err)
149 return err > 0 ? -EINVAL : err;
150
151 addr = (loff_t)pnum * ubi->peb_size + offset;
152retry:
153 err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
154 if (err) {
155 if (err == -EUCLEAN) {
156 /*
157 * -EUCLEAN is reported if there was a bit-flip which
158 * was corrected, so this is harmless.
159 */
160 ubi_msg("fixable bit-flip detected at PEB %d", pnum);
161 ubi_assert(len == read);
162 return UBI_IO_BITFLIPS;
163 }
164
165 if (read != len && retries++ < UBI_IO_RETRIES) {
166 dbg_io("error %d while reading %d bytes from PEB %d:%d, "
167 "read only %zd bytes, retry",
168 err, len, pnum, offset, read);
169 yield();
170 goto retry;
171 }
172
173 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
174 "read %zd bytes", err, len, pnum, offset, read);
175 ubi_dbg_dump_stack();
176 } else {
177 ubi_assert(len == read);
178
179 if (ubi_dbg_is_bitflip()) {
180 dbg_msg("bit-flip (emulated)");
181 err = UBI_IO_BITFLIPS;
182 }
183 }
184
185 return err;
186}
187
188/**
189 * ubi_io_write - write data to a physical eraseblock.
190 * @ubi: UBI device description object
191 * @buf: buffer with the data to write
192 * @pnum: physical eraseblock number to write to
193 * @offset: offset within the physical eraseblock where to write
194 * @len: how many bytes to write
195 *
196 * This function writes @len bytes of data from buffer @buf to offset @offset
197 * of physical eraseblock @pnum. If all the data were successfully written,
198 * zero is returned. If an error occurred, this function returns a negative
199 * error code. If %-EIO is returned, the physical eraseblock most probably went
200 * bad.
201 *
202 * Note, in case of an error, it is possible that something was still written
203 * to the flash media, but may be some garbage.
204 */
205int ubi_io_write(const struct ubi_device *ubi, const void *buf, int pnum,
206 int offset, int len)
207{
208 int err;
209 size_t written;
210 loff_t addr;
211
212 dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
213
214 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
215 ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
216 ubi_assert(offset % ubi->hdrs_min_io_size == 0);
217 ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
218
219 if (ubi->ro_mode) {
220 ubi_err("read-only mode");
221 return -EROFS;
222 }
223
224 /* The below has to be compiled out if paranoid checks are disabled */
225
226 err = paranoid_check_not_bad(ubi, pnum);
227 if (err)
228 return err > 0 ? -EINVAL : err;
229
230 /* The area we are writing to has to contain all 0xFF bytes */
231 err = paranoid_check_all_ff(ubi, pnum, offset, len);
232 if (err)
233 return err > 0 ? -EINVAL : err;
234
235 if (offset >= ubi->leb_start) {
236 /*
237 * We write to the data area of the physical eraseblock. Make
238 * sure it has valid EC and VID headers.
239 */
240 err = paranoid_check_peb_ec_hdr(ubi, pnum);
241 if (err)
242 return err > 0 ? -EINVAL : err;
243 err = paranoid_check_peb_vid_hdr(ubi, pnum);
244 if (err)
245 return err > 0 ? -EINVAL : err;
246 }
247
248 if (ubi_dbg_is_write_failure()) {
249 dbg_err("cannot write %d bytes to PEB %d:%d "
250 "(emulated)", len, pnum, offset);
251 ubi_dbg_dump_stack();
252 return -EIO;
253 }
254
255 addr = (loff_t)pnum * ubi->peb_size + offset;
256 err = ubi->mtd->write(ubi->mtd, addr, len, &written, buf);
257 if (err) {
258 ubi_err("error %d while writing %d bytes to PEB %d:%d, written"
259 " %zd bytes", err, len, pnum, offset, written);
260 ubi_dbg_dump_stack();
261 } else
262 ubi_assert(written == len);
263
264 return err;
265}
266
267/**
268 * erase_callback - MTD erasure call-back.
269 * @ei: MTD erase information object.
270 *
271 * Note, even though MTD erase interface is asynchronous, all the current
272 * implementations are synchronous anyway.
273 */
274static void erase_callback(struct erase_info *ei)
275{
276 wake_up_interruptible((wait_queue_head_t *)ei->priv);
277}
278
279/**
280 * do_sync_erase - synchronously erase a physical eraseblock.
281 * @ubi: UBI device description object
282 * @pnum: the physical eraseblock number to erase
283 *
284 * This function synchronously erases physical eraseblock @pnum and returns
285 * zero in case of success and a negative error code in case of failure. If
286 * %-EIO is returned, the physical eraseblock most probably went bad.
287 */
288static int do_sync_erase(const struct ubi_device *ubi, int pnum)
289{
290 int err, retries = 0;
291 struct erase_info ei;
292 wait_queue_head_t wq;
293
294 dbg_io("erase PEB %d", pnum);
295
296retry:
297 init_waitqueue_head(&wq);
298 memset(&ei, 0, sizeof(struct erase_info));
299
300 ei.mtd = ubi->mtd;
301 ei.addr = pnum * ubi->peb_size;
302 ei.len = ubi->peb_size;
303 ei.callback = erase_callback;
304 ei.priv = (unsigned long)&wq;
305
306 err = ubi->mtd->erase(ubi->mtd, &ei);
307 if (err) {
308 if (retries++ < UBI_IO_RETRIES) {
309 dbg_io("error %d while erasing PEB %d, retry",
310 err, pnum);
311 yield();
312 goto retry;
313 }
314 ubi_err("cannot erase PEB %d, error %d", pnum, err);
315 ubi_dbg_dump_stack();
316 return err;
317 }
318
319 err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
320 ei.state == MTD_ERASE_FAILED);
321 if (err) {
322 ubi_err("interrupted PEB %d erasure", pnum);
323 return -EINTR;
324 }
325
326 if (ei.state == MTD_ERASE_FAILED) {
327 if (retries++ < UBI_IO_RETRIES) {
328 dbg_io("error while erasing PEB %d, retry", pnum);
329 yield();
330 goto retry;
331 }
332 ubi_err("cannot erase PEB %d", pnum);
333 ubi_dbg_dump_stack();
334 return -EIO;
335 }
336
337 err = paranoid_check_all_ff(ubi, pnum, 0, ubi->peb_size);
338 if (err)
339 return err > 0 ? -EINVAL : err;
340
341 if (ubi_dbg_is_erase_failure() && !err) {
342 dbg_err("cannot erase PEB %d (emulated)", pnum);
343 return -EIO;
344 }
345
346 return 0;
347}
348
349/**
350 * check_pattern - check if buffer contains only a certain byte pattern.
351 * @buf: buffer to check
352 * @patt: the pattern to check
353 * @size: buffer size in bytes
354 *
355 * This function returns %1 in there are only @patt bytes in @buf, and %0 if
356 * something else was also found.
357 */
358static int check_pattern(const void *buf, uint8_t patt, int size)
359{
360 int i;
361
362 for (i = 0; i < size; i++)
363 if (((const uint8_t *)buf)[i] != patt)
364 return 0;
365 return 1;
366}
367
368/* Patterns to write to a physical eraseblock when torturing it */
369static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
370
371/**
372 * torture_peb - test a supposedly bad physical eraseblock.
373 * @ubi: UBI device description object
374 * @pnum: the physical eraseblock number to test
375 *
376 * This function returns %-EIO if the physical eraseblock did not pass the
377 * test, a positive number of erase operations done if the test was
378 * successfully passed, and other negative error codes in case of other errors.
379 */
380static int torture_peb(const struct ubi_device *ubi, int pnum)
381{
382 void *buf;
383 int err, i, patt_count;
384
385 buf = kmalloc(ubi->peb_size, GFP_KERNEL);
386 if (!buf)
387 return -ENOMEM;
388
389 patt_count = ARRAY_SIZE(patterns);
390 ubi_assert(patt_count > 0);
391
392 for (i = 0; i < patt_count; i++) {
393 err = do_sync_erase(ubi, pnum);
394 if (err)
395 goto out;
396
397 /* Make sure the PEB contains only 0xFF bytes */
398 err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size);
399 if (err)
400 goto out;
401
402 err = check_pattern(buf, 0xFF, ubi->peb_size);
403 if (err == 0) {
404 ubi_err("erased PEB %d, but a non-0xFF byte found",
405 pnum);
406 err = -EIO;
407 goto out;
408 }
409
410 /* Write a pattern and check it */
411 memset(buf, patterns[i], ubi->peb_size);
412 err = ubi_io_write(ubi, buf, pnum, 0, ubi->peb_size);
413 if (err)
414 goto out;
415
416 memset(buf, ~patterns[i], ubi->peb_size);
417 err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size);
418 if (err)
419 goto out;
420
421 err = check_pattern(buf, patterns[i], ubi->peb_size);
422 if (err == 0) {
423 ubi_err("pattern %x checking failed for PEB %d",
424 patterns[i], pnum);
425 err = -EIO;
426 goto out;
427 }
428 }
429
430 err = patt_count;
431
432out:
433 if (err == UBI_IO_BITFLIPS || err == -EBADMSG)
434 /*
435 * If a bit-flip or data integrity error was detected, the test
436 * has not passed because it happened on a freshly erased
437 * physical eraseblock which means something is wrong with it.
438 */
439 err = -EIO;
440 kfree(buf);
441 return err;
442}
443
444/**
445 * ubi_io_sync_erase - synchronously erase a physical eraseblock.
446 * @ubi: UBI device description object
447 * @pnum: physical eraseblock number to erase
448 * @torture: if this physical eraseblock has to be tortured
449 *
450 * This function synchronously erases physical eraseblock @pnum. If @torture
451 * flag is not zero, the physical eraseblock is checked by means of writing
452 * different patterns to it and reading them back. If the torturing is enabled,
453 * the physical eraseblock is erased more then once.
454 *
455 * This function returns the number of erasures made in case of success, %-EIO
456 * if the erasure failed or the torturing test failed, and other negative error
457 * codes in case of other errors. Note, %-EIO means that the physical
458 * eraseblock is bad.
459 */
460int ubi_io_sync_erase(const struct ubi_device *ubi, int pnum, int torture)
461{
462 int err, ret = 0;
463
464 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
465
466 err = paranoid_check_not_bad(ubi, pnum);
467 if (err != 0)
468 return err > 0 ? -EINVAL : err;
469
470 if (ubi->ro_mode) {
471 ubi_err("read-only mode");
472 return -EROFS;
473 }
474
475 if (torture) {
476 ret = torture_peb(ubi, pnum);
477 if (ret < 0)
478 return ret;
479 }
480
481 err = do_sync_erase(ubi, pnum);
482 if (err)
483 return err;
484
485 return ret + 1;
486}
487
488/**
489 * ubi_io_is_bad - check if a physical eraseblock is bad.
490 * @ubi: UBI device description object
491 * @pnum: the physical eraseblock number to check
492 *
493 * This function returns a positive number if the physical eraseblock is bad,
494 * zero if not, and a negative error code if an error occurred.
495 */
496int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
497{
498 struct mtd_info *mtd = ubi->mtd;
499
500 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
501
502 if (ubi->bad_allowed) {
503 int ret;
504
505 ret = mtd->block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
506 if (ret < 0)
507 ubi_err("error %d while checking if PEB %d is bad",
508 ret, pnum);
509 else if (ret)
510 dbg_io("PEB %d is bad", pnum);
511 return ret;
512 }
513
514 return 0;
515}
516
517/**
518 * ubi_io_mark_bad - mark a physical eraseblock as bad.
519 * @ubi: UBI device description object
520 * @pnum: the physical eraseblock number to mark
521 *
522 * This function returns zero in case of success and a negative error code in
523 * case of failure.
524 */
525int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
526{
527 int err;
528 struct mtd_info *mtd = ubi->mtd;
529
530 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
531
532 if (ubi->ro_mode) {
533 ubi_err("read-only mode");
534 return -EROFS;
535 }
536
537 if (!ubi->bad_allowed)
538 return 0;
539
540 err = mtd->block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
541 if (err)
542 ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
543 return err;
544}
545
546/**
547 * validate_ec_hdr - validate an erase counter header.
548 * @ubi: UBI device description object
549 * @ec_hdr: the erase counter header to check
550 *
551 * This function returns zero if the erase counter header is OK, and %1 if
552 * not.
553 */
554static int validate_ec_hdr(const struct ubi_device *ubi,
555 const struct ubi_ec_hdr *ec_hdr)
556{
557 long long ec;
558 int vid_hdr_offset, leb_start;
559
560 ec = ubi64_to_cpu(ec_hdr->ec);
561 vid_hdr_offset = ubi32_to_cpu(ec_hdr->vid_hdr_offset);
562 leb_start = ubi32_to_cpu(ec_hdr->data_offset);
563
564 if (ec_hdr->version != UBI_VERSION) {
565 ubi_err("node with incompatible UBI version found: "
566 "this UBI version is %d, image version is %d",
567 UBI_VERSION, (int)ec_hdr->version);
568 goto bad;
569 }
570
571 if (vid_hdr_offset != ubi->vid_hdr_offset) {
572 ubi_err("bad VID header offset %d, expected %d",
573 vid_hdr_offset, ubi->vid_hdr_offset);
574 goto bad;
575 }
576
577 if (leb_start != ubi->leb_start) {
578 ubi_err("bad data offset %d, expected %d",
579 leb_start, ubi->leb_start);
580 goto bad;
581 }
582
583 if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
584 ubi_err("bad erase counter %lld", ec);
585 goto bad;
586 }
587
588 return 0;
589
590bad:
591 ubi_err("bad EC header");
592 ubi_dbg_dump_ec_hdr(ec_hdr);
593 ubi_dbg_dump_stack();
594 return 1;
595}
596
597/**
598 * ubi_io_read_ec_hdr - read and check an erase counter header.
599 * @ubi: UBI device description object
600 * @pnum: physical eraseblock to read from
601 * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
602 * header
603 * @verbose: be verbose if the header is corrupted or was not found
604 *
605 * This function reads erase counter header from physical eraseblock @pnum and
606 * stores it in @ec_hdr. This function also checks CRC checksum of the read
607 * erase counter header. The following codes may be returned:
608 *
609 * o %0 if the CRC checksum is correct and the header was successfully read;
610 * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
611 * and corrected by the flash driver; this is harmless but may indicate that
612 * this eraseblock may become bad soon (but may be not);
613 * o %UBI_IO_BAD_EC_HDR if the erase counter header is corrupted (a CRC error);
614 * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
615 * o a negative error code in case of failure.
616 */
617int ubi_io_read_ec_hdr(const struct ubi_device *ubi, int pnum,
618 struct ubi_ec_hdr *ec_hdr, int verbose)
619{
620 int err, read_err = 0;
621 uint32_t crc, magic, hdr_crc;
622
623 dbg_io("read EC header from PEB %d", pnum);
624 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
625
626 err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
627 if (err) {
628 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
629 return err;
630
631 /*
632 * We read all the data, but either a correctable bit-flip
633 * occurred, or MTD reported about some data integrity error,
634 * like an ECC error in case of NAND. The former is harmless,
635 * the later may mean that the read data is corrupted. But we
636 * have a CRC check-sum and we will detect this. If the EC
637 * header is still OK, we just report this as there was a
638 * bit-flip.
639 */
640 read_err = err;
641 }
642
643 magic = ubi32_to_cpu(ec_hdr->magic);
644 if (magic != UBI_EC_HDR_MAGIC) {
645 /*
646 * The magic field is wrong. Let's check if we have read all
647 * 0xFF. If yes, this physical eraseblock is assumed to be
648 * empty.
649 *
650 * But if there was a read error, we do not test it for all
651 * 0xFFs. Even if it does contain all 0xFFs, this error
652 * indicates that something is still wrong with this physical
653 * eraseblock and we anyway cannot treat it as empty.
654 */
655 if (read_err != -EBADMSG &&
656 check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
657 /* The physical eraseblock is supposedly empty */
658
659 /*
660 * The below is just a paranoid check, it has to be
661 * compiled out if paranoid checks are disabled.
662 */
663 err = paranoid_check_all_ff(ubi, pnum, 0,
664 ubi->peb_size);
665 if (err)
666 return err > 0 ? UBI_IO_BAD_EC_HDR : err;
667
668 if (verbose)
669 ubi_warn("no EC header found at PEB %d, "
670 "only 0xFF bytes", pnum);
671 return UBI_IO_PEB_EMPTY;
672 }
673
674 /*
675 * This is not a valid erase counter header, and these are not
676 * 0xFF bytes. Report that the header is corrupted.
677 */
678 if (verbose) {
679 ubi_warn("bad magic number at PEB %d: %08x instead of "
680 "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
681 ubi_dbg_dump_ec_hdr(ec_hdr);
682 }
683 return UBI_IO_BAD_EC_HDR;
684 }
685
686 crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
687 hdr_crc = ubi32_to_cpu(ec_hdr->hdr_crc);
688
689 if (hdr_crc != crc) {
690 if (verbose) {
691 ubi_warn("bad EC header CRC at PEB %d, calculated %#08x,"
692 " read %#08x", pnum, crc, hdr_crc);
693 ubi_dbg_dump_ec_hdr(ec_hdr);
694 }
695 return UBI_IO_BAD_EC_HDR;
696 }
697
698 /* And of course validate what has just been read from the media */
699 err = validate_ec_hdr(ubi, ec_hdr);
700 if (err) {
701 ubi_err("validation failed for PEB %d", pnum);
702 return -EINVAL;
703 }
704
705 return read_err ? UBI_IO_BITFLIPS : 0;
706}
707
708/**
709 * ubi_io_write_ec_hdr - write an erase counter header.
710 * @ubi: UBI device description object
711 * @pnum: physical eraseblock to write to
712 * @ec_hdr: the erase counter header to write
713 *
714 * This function writes erase counter header described by @ec_hdr to physical
715 * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
716 * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
717 * field.
718 *
719 * This function returns zero in case of success and a negative error code in
720 * case of failure. If %-EIO is returned, the physical eraseblock most probably
721 * went bad.
722 */
723int ubi_io_write_ec_hdr(const struct ubi_device *ubi, int pnum,
724 struct ubi_ec_hdr *ec_hdr)
725{
726 int err;
727 uint32_t crc;
728
729 dbg_io("write EC header to PEB %d", pnum);
730 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
731
732 ec_hdr->magic = cpu_to_ubi32(UBI_EC_HDR_MAGIC);
733 ec_hdr->version = UBI_VERSION;
734 ec_hdr->vid_hdr_offset = cpu_to_ubi32(ubi->vid_hdr_offset);
735 ec_hdr->data_offset = cpu_to_ubi32(ubi->leb_start);
736 crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
737 ec_hdr->hdr_crc = cpu_to_ubi32(crc);
738
739 err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
740 if (err)
741 return -EINVAL;
742
743 err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
744 return err;
745}
746
747/**
748 * validate_vid_hdr - validate a volume identifier header.
749 * @ubi: UBI device description object
750 * @vid_hdr: the volume identifier header to check
751 *
752 * This function checks that data stored in the volume identifier header
753 * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
754 */
755static int validate_vid_hdr(const struct ubi_device *ubi,
756 const struct ubi_vid_hdr *vid_hdr)
757{
758 int vol_type = vid_hdr->vol_type;
759 int copy_flag = vid_hdr->copy_flag;
760 int vol_id = ubi32_to_cpu(vid_hdr->vol_id);
761 int lnum = ubi32_to_cpu(vid_hdr->lnum);
762 int compat = vid_hdr->compat;
763 int data_size = ubi32_to_cpu(vid_hdr->data_size);
764 int used_ebs = ubi32_to_cpu(vid_hdr->used_ebs);
765 int data_pad = ubi32_to_cpu(vid_hdr->data_pad);
766 int data_crc = ubi32_to_cpu(vid_hdr->data_crc);
767 int usable_leb_size = ubi->leb_size - data_pad;
768
769 if (copy_flag != 0 && copy_flag != 1) {
770 dbg_err("bad copy_flag");
771 goto bad;
772 }
773
774 if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
775 data_pad < 0) {
776 dbg_err("negative values");
777 goto bad;
778 }
779
780 if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
781 dbg_err("bad vol_id");
782 goto bad;
783 }
784
785 if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
786 dbg_err("bad compat");
787 goto bad;
788 }
789
790 if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
791 compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
792 compat != UBI_COMPAT_REJECT) {
793 dbg_err("bad compat");
794 goto bad;
795 }
796
797 if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
798 dbg_err("bad vol_type");
799 goto bad;
800 }
801
802 if (data_pad >= ubi->leb_size / 2) {
803 dbg_err("bad data_pad");
804 goto bad;
805 }
806
807 if (vol_type == UBI_VID_STATIC) {
808 /*
809 * Although from high-level point of view static volumes may
810 * contain zero bytes of data, but no VID headers can contain
811 * zero at these fields, because they empty volumes do not have
812 * mapped logical eraseblocks.
813 */
814 if (used_ebs == 0) {
815 dbg_err("zero used_ebs");
816 goto bad;
817 }
818 if (data_size == 0) {
819 dbg_err("zero data_size");
820 goto bad;
821 }
822 if (lnum < used_ebs - 1) {
823 if (data_size != usable_leb_size) {
824 dbg_err("bad data_size");
825 goto bad;
826 }
827 } else if (lnum == used_ebs - 1) {
828 if (data_size == 0) {
829 dbg_err("bad data_size at last LEB");
830 goto bad;
831 }
832 } else {
833 dbg_err("too high lnum");
834 goto bad;
835 }
836 } else {
837 if (copy_flag == 0) {
838 if (data_crc != 0) {
839 dbg_err("non-zero data CRC");
840 goto bad;
841 }
842 if (data_size != 0) {
843 dbg_err("non-zero data_size");
844 goto bad;
845 }
846 } else {
847 if (data_size == 0) {
848 dbg_err("zero data_size of copy");
849 goto bad;
850 }
851 }
852 if (used_ebs != 0) {
853 dbg_err("bad used_ebs");
854 goto bad;
855 }
856 }
857
858 return 0;
859
860bad:
861 ubi_err("bad VID header");
862 ubi_dbg_dump_vid_hdr(vid_hdr);
863 ubi_dbg_dump_stack();
864 return 1;
865}
866
867/**
868 * ubi_io_read_vid_hdr - read and check a volume identifier header.
869 * @ubi: UBI device description object
870 * @pnum: physical eraseblock number to read from
871 * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
872 * identifier header
873 * @verbose: be verbose if the header is corrupted or wasn't found
874 *
875 * This function reads the volume identifier header from physical eraseblock
876 * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
877 * volume identifier header. The following codes may be returned:
878 *
879 * o %0 if the CRC checksum is correct and the header was successfully read;
880 * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
881 * and corrected by the flash driver; this is harmless but may indicate that
882 * this eraseblock may become bad soon;
883 * o %UBI_IO_BAD_VID_HRD if the volume identifier header is corrupted (a CRC
884 * error detected);
885 * o %UBI_IO_PEB_FREE if the physical eraseblock is free (i.e., there is no VID
886 * header there);
887 * o a negative error code in case of failure.
888 */
889int ubi_io_read_vid_hdr(const struct ubi_device *ubi, int pnum,
890 struct ubi_vid_hdr *vid_hdr, int verbose)
891{
892 int err, read_err = 0;
893 uint32_t crc, magic, hdr_crc;
894 void *p;
895
896 dbg_io("read VID header from PEB %d", pnum);
897 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
898
899 p = (char *)vid_hdr - ubi->vid_hdr_shift;
900 err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
901 ubi->vid_hdr_alsize);
902 if (err) {
903 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
904 return err;
905
906 /*
907 * We read all the data, but either a correctable bit-flip
908 * occurred, or MTD reported about some data integrity error,
909 * like an ECC error in case of NAND. The former is harmless,
910 * the later may mean the read data is corrupted. But we have a
911 * CRC check-sum and we will identify this. If the VID header is
912 * still OK, we just report this as there was a bit-flip.
913 */
914 read_err = err;
915 }
916
917 magic = ubi32_to_cpu(vid_hdr->magic);
918 if (magic != UBI_VID_HDR_MAGIC) {
919 /*
920 * If we have read all 0xFF bytes, the VID header probably does
921 * not exist and the physical eraseblock is assumed to be free.
922 *
923 * But if there was a read error, we do not test the data for
924 * 0xFFs. Even if it does contain all 0xFFs, this error
925 * indicates that something is still wrong with this physical
926 * eraseblock and it cannot be regarded as free.
927 */
928 if (read_err != -EBADMSG &&
929 check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
930 /* The physical eraseblock is supposedly free */
931
932 /*
933 * The below is just a paranoid check, it has to be
934 * compiled out if paranoid checks are disabled.
935 */
936 err = paranoid_check_all_ff(ubi, pnum, ubi->leb_start,
937 ubi->leb_size);
938 if (err)
939 return err > 0 ? UBI_IO_BAD_VID_HDR : err;
940
941 if (verbose)
942 ubi_warn("no VID header found at PEB %d, "
943 "only 0xFF bytes", pnum);
944 return UBI_IO_PEB_FREE;
945 }
946
947 /*
948 * This is not a valid VID header, and these are not 0xFF
949 * bytes. Report that the header is corrupted.
950 */
951 if (verbose) {
952 ubi_warn("bad magic number at PEB %d: %08x instead of "
953 "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
954 ubi_dbg_dump_vid_hdr(vid_hdr);
955 }
956 return UBI_IO_BAD_VID_HDR;
957 }
958
959 crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
960 hdr_crc = ubi32_to_cpu(vid_hdr->hdr_crc);
961
962 if (hdr_crc != crc) {
963 if (verbose) {
964 ubi_warn("bad CRC at PEB %d, calculated %#08x, "
965 "read %#08x", pnum, crc, hdr_crc);
966 ubi_dbg_dump_vid_hdr(vid_hdr);
967 }
968 return UBI_IO_BAD_VID_HDR;
969 }
970
971 /* Validate the VID header that we have just read */
972 err = validate_vid_hdr(ubi, vid_hdr);
973 if (err) {
974 ubi_err("validation failed for PEB %d", pnum);
975 return -EINVAL;
976 }
977
978 return read_err ? UBI_IO_BITFLIPS : 0;
979}
980
981/**
982 * ubi_io_write_vid_hdr - write a volume identifier header.
983 * @ubi: UBI device description object
984 * @pnum: the physical eraseblock number to write to
985 * @vid_hdr: the volume identifier header to write
986 *
987 * This function writes the volume identifier header described by @vid_hdr to
988 * physical eraseblock @pnum. This function automatically fills the
989 * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
990 * header CRC checksum and stores it at vid_hdr->hdr_crc.
991 *
992 * This function returns zero in case of success and a negative error code in
993 * case of failure. If %-EIO is returned, the physical eraseblock probably went
994 * bad.
995 */
996int ubi_io_write_vid_hdr(const struct ubi_device *ubi, int pnum,
997 struct ubi_vid_hdr *vid_hdr)
998{
999 int err;
1000 uint32_t crc;
1001 void *p;
1002
1003 dbg_io("write VID header to PEB %d", pnum);
1004 ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
1005
1006 err = paranoid_check_peb_ec_hdr(ubi, pnum);
1007 if (err)
1008 return err > 0 ? -EINVAL: err;
1009
1010 vid_hdr->magic = cpu_to_ubi32(UBI_VID_HDR_MAGIC);
1011 vid_hdr->version = UBI_VERSION;
1012 crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1013 vid_hdr->hdr_crc = cpu_to_ubi32(crc);
1014
1015 err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1016 if (err)
1017 return -EINVAL;
1018
1019 p = (char *)vid_hdr - ubi->vid_hdr_shift;
1020 err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1021 ubi->vid_hdr_alsize);
1022 return err;
1023}
1024
1025#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1026
1027/**
1028 * paranoid_check_not_bad - ensure that a physical eraseblock is not bad.
1029 * @ubi: UBI device description object
1030 * @pnum: physical eraseblock number to check
1031 *
1032 * This function returns zero if the physical eraseblock is good, a positive
1033 * number if it is bad and a negative error code if an error occurred.
1034 */
1035static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum)
1036{
1037 int err;
1038
1039 err = ubi_io_is_bad(ubi, pnum);
1040 if (!err)
1041 return err;
1042
1043 ubi_err("paranoid check failed for PEB %d", pnum);
1044 ubi_dbg_dump_stack();
1045 return err;
1046}
1047
1048/**
1049 * paranoid_check_ec_hdr - check if an erase counter header is all right.
1050 * @ubi: UBI device description object
1051 * @pnum: physical eraseblock number the erase counter header belongs to
1052 * @ec_hdr: the erase counter header to check
1053 *
1054 * This function returns zero if the erase counter header contains valid
1055 * values, and %1 if not.
1056 */
1057static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1058 const struct ubi_ec_hdr *ec_hdr)
1059{
1060 int err;
1061 uint32_t magic;
1062
1063 magic = ubi32_to_cpu(ec_hdr->magic);
1064 if (magic != UBI_EC_HDR_MAGIC) {
1065 ubi_err("bad magic %#08x, must be %#08x",
1066 magic, UBI_EC_HDR_MAGIC);
1067 goto fail;
1068 }
1069
1070 err = validate_ec_hdr(ubi, ec_hdr);
1071 if (err) {
1072 ubi_err("paranoid check failed for PEB %d", pnum);
1073 goto fail;
1074 }
1075
1076 return 0;
1077
1078fail:
1079 ubi_dbg_dump_ec_hdr(ec_hdr);
1080 ubi_dbg_dump_stack();
1081 return 1;
1082}
1083
1084/**
1085 * paranoid_check_peb_ec_hdr - check that the erase counter header of a
1086 * physical eraseblock is in-place and is all right.
1087 * @ubi: UBI device description object
1088 * @pnum: the physical eraseblock number to check
1089 *
1090 * This function returns zero if the erase counter header is all right, %1 if
1091 * not, and a negative error code if an error occurred.
1092 */
1093static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1094{
1095 int err;
1096 uint32_t crc, hdr_crc;
1097 struct ubi_ec_hdr *ec_hdr;
1098
1099 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1100 if (!ec_hdr)
1101 return -ENOMEM;
1102
1103 err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1104 if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1105 goto exit;
1106
1107 crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1108 hdr_crc = ubi32_to_cpu(ec_hdr->hdr_crc);
1109 if (hdr_crc != crc) {
1110 ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
1111 ubi_err("paranoid check failed for PEB %d", pnum);
1112 ubi_dbg_dump_ec_hdr(ec_hdr);
1113 ubi_dbg_dump_stack();
1114 err = 1;
1115 goto exit;
1116 }
1117
1118 err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
1119
1120exit:
1121 kfree(ec_hdr);
1122 return err;
1123}
1124
1125/**
1126 * paranoid_check_vid_hdr - check that a volume identifier header is all right.
1127 * @ubi: UBI device description object
1128 * @pnum: physical eraseblock number the volume identifier header belongs to
1129 * @vid_hdr: the volume identifier header to check
1130 *
1131 * This function returns zero if the volume identifier header is all right, and
1132 * %1 if not.
1133 */
1134static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1135 const struct ubi_vid_hdr *vid_hdr)
1136{
1137 int err;
1138 uint32_t magic;
1139
1140 magic = ubi32_to_cpu(vid_hdr->magic);
1141 if (magic != UBI_VID_HDR_MAGIC) {
1142 ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
1143 magic, pnum, UBI_VID_HDR_MAGIC);
1144 goto fail;
1145 }
1146
1147 err = validate_vid_hdr(ubi, vid_hdr);
1148 if (err) {
1149 ubi_err("paranoid check failed for PEB %d", pnum);
1150 goto fail;
1151 }
1152
1153 return err;
1154
1155fail:
1156 ubi_err("paranoid check failed for PEB %d", pnum);
1157 ubi_dbg_dump_vid_hdr(vid_hdr);
1158 ubi_dbg_dump_stack();
1159 return 1;
1160
1161}
1162
1163/**
1164 * paranoid_check_peb_vid_hdr - check that the volume identifier header of a
1165 * physical eraseblock is in-place and is all right.
1166 * @ubi: UBI device description object
1167 * @pnum: the physical eraseblock number to check
1168 *
1169 * This function returns zero if the volume identifier header is all right,
1170 * %1 if not, and a negative error code if an error occurred.
1171 */
1172static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1173{
1174 int err;
1175 uint32_t crc, hdr_crc;
1176 struct ubi_vid_hdr *vid_hdr;
1177 void *p;
1178
1179 vid_hdr = ubi_zalloc_vid_hdr(ubi);
1180 if (!vid_hdr)
1181 return -ENOMEM;
1182
1183 p = (char *)vid_hdr - ubi->vid_hdr_shift;
1184 err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1185 ubi->vid_hdr_alsize);
1186 if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1187 goto exit;
1188
1189 crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
1190 hdr_crc = ubi32_to_cpu(vid_hdr->hdr_crc);
1191 if (hdr_crc != crc) {
1192 ubi_err("bad VID header CRC at PEB %d, calculated %#08x, "
1193 "read %#08x", pnum, crc, hdr_crc);
1194 ubi_err("paranoid check failed for PEB %d", pnum);
1195 ubi_dbg_dump_vid_hdr(vid_hdr);
1196 ubi_dbg_dump_stack();
1197 err = 1;
1198 goto exit;
1199 }
1200
1201 err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1202
1203exit:
1204 ubi_free_vid_hdr(ubi, vid_hdr);
1205 return err;
1206}
1207
1208/**
1209 * paranoid_check_all_ff - check that a region of flash is empty.
1210 * @ubi: UBI device description object
1211 * @pnum: the physical eraseblock number to check
1212 * @offset: the starting offset within the physical eraseblock to check
1213 * @len: the length of the region to check
1214 *
1215 * This function returns zero if only 0xFF bytes are present at offset
1216 * @offset of the physical eraseblock @pnum, %1 if not, and a negative error
1217 * code if an error occurred.
1218 */
1219static int paranoid_check_all_ff(const struct ubi_device *ubi, int pnum,
1220 int offset, int len)
1221{
1222 size_t read;
1223 int err;
1224 void *buf;
1225 loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1226
1227 buf = kzalloc(len, GFP_KERNEL);
1228 if (!buf)
1229 return -ENOMEM;
1230
1231 err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
1232 if (err && err != -EUCLEAN) {
1233 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
1234 "read %zd bytes", err, len, pnum, offset, read);
1235 goto error;
1236 }
1237
1238 err = check_pattern(buf, 0xFF, len);
1239 if (err == 0) {
1240 ubi_err("flash region at PEB %d:%d, length %d does not "
1241 "contain all 0xFF bytes", pnum, offset, len);
1242 goto fail;
1243 }
1244
1245 kfree(buf);
1246 return 0;
1247
1248fail:
1249 ubi_err("paranoid check failed for PEB %d", pnum);
1250 dbg_msg("hex dump of the %d-%d region", offset, offset + len);
1251 ubi_dbg_hexdump(buf, len);
1252 err = 1;
1253error:
1254 ubi_dbg_dump_stack();
1255 kfree(buf);
1256 return err;
1257}
1258
1259#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-22 07:55:27 -0500