/*
* Copyright (c) International Business Machines Corp., 2006
* Copyright (c) Nokia Corporation, 2006, 2007
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Artem Bityutskiy (Битюцкий Артём)
*/
/*
* UBI input/output unit.
*
* This unit provides a uniform way to work with all kinds of the underlying
* MTD devices. It also implements handy functions for reading and writing UBI
* headers.
*
* We are trying to have a paranoid mindset and not to trust to what we read
* from the flash media in order to be more secure and robust. So this unit
* validates every single header it reads from the flash media.
*
* Some words about how the eraseblock headers are stored.
*
* The erase counter header is always stored at offset zero. By default, the
* VID header is stored after the EC header at the closest aligned offset
* (i.e. aligned to the minimum I/O unit size). Data starts next to the VID
* header at the closest aligned offset. But this default layout may be
* changed. For example, for different reasons (e.g., optimization) UBI may be
* asked to put the VID header at further offset, and even at an unaligned
* offset. Of course, if the offset of the VID header is unaligned, UBI adds
* proper padding in front of it. Data offset may also be changed but it has to
* be aligned.
*
* About minimal I/O units. In general, UBI assumes flash device model where
* there is only one minimal I/O unit size. E.g., in case of NOR flash it is 1,
* in case of NAND flash it is a NAND page, etc. This is reported by MTD in the
* @ubi->mtd->writesize field. But as an exception, UBI admits of using another
* (smaller) minimal I/O unit size for EC and VID headers to make it possible
* to do different optimizations.
*
* This is extremely useful in case of NAND flashes which admit of several
* write operations to one NAND page. In this case UBI can fit EC and VID
* headers at one NAND page. Thus, UBI may use "sub-page" size as the minimal
* I/O unit for the headers (the @ubi->hdrs_min_io_size field). But it still
* reports NAND page size (@ubi->min_io_size) as a minimal I/O unit for the UBI
* users.
*
* Example: some Samsung NANDs with 2KiB pages allow 4x 512-byte writes, so
* although the minimal I/O unit is 2K, UBI uses 512 bytes for EC and VID
* headers.
*
* Q: why not just to treat sub-page as a minimal I/O unit of this flash
* device, e.g., make @ubi->min_io_size = 512 in the example above?
*
* A: because when writing a sub-page, MTD still writes a full 2K page but the
* bytes which are no relevant to the sub-page are 0xFF. So, basically, writing
* 4x512 sub-pages is 4 times slower then writing one 2KiB NAND page. Thus, we
* prefer to use sub-pages only for EV and VID headers.
*
* As it was noted above, the VID header may start at a non-aligned offset.
* For example, in case of a 2KiB page NAND flash with a 512 bytes sub-page,
* the VID header may reside at offset 1984 which is the last 64 bytes of the
* last sub-page (EC header is always at offset zero). This causes some
* difficulties when reading and writing VID headers.
*
* Suppose we have a 64-byte buffer and we read a VID header at it. We change
* the data and want to write this VID header out. As we can only write in
* 512-byte chunks, we have to allocate one more buffer and copy our VID header
* to offset 448 of this buffer.
*
* The I/O unit does the following trick in order to avoid this extra copy.
* It always allocates a @ubi->vid_hdr_alsize bytes buffer for the VID header
* and returns a pointer to offset @ubi->vid_hdr_shift of this buffer. When the
* VID header is being written out, it shifts the VID header pointer back and
* writes the whole sub-page.
*/
#include <linux/crc32.h>
#include <linux/err.h>
#include "ubi.h"
#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum);
static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_ec_hdr *ec_hdr);
static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_vid_hdr *vid_hdr);
static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
int len);
#else
#define paranoid_check_not_bad(ubi, pnum) 0
#define paranoid_check_peb_ec_hdr(ubi, pnum) 0
#define paranoid_check_ec_hdr(ubi, pnum, ec_hdr) 0
#define paranoid_check_peb_vid_hdr(ubi, pnum) 0
#define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0
#define paranoid_check_all_ff(ubi, pnum, offset, len) 0
#endif
/**
* ubi_io_read - read data from a physical eraseblock.
* @ubi: UBI device description object
* @buf: buffer where to store the read data
* @pnum: physical eraseblock number to read from
* @offset: offset within the physical eraseblock from where to read
* @len: how many bytes to read
*
* This function reads data from offset @offset of physical eraseblock @pnum
* and stores the read data in the @buf buffer. The following return codes are
* possible:
*
* o %0 if all the requested data were successfully read;
* o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
* correctable bit-flips were detected; this is harmless but may indicate
* that this eraseblock may become bad soon (but do not have to);
* o %-EBADMSG if the MTD subsystem reported about data integrity problems, for
* example it can be an ECC error in case of NAND; this most probably means
* that the data is corrupted;
* o %-EIO if some I/O error occurred;
* o other negative error codes in case of other errors.
*/
int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
int len)
{
int err, retries = 0;
size_t read;
loff_t addr;
dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
ubi_assert(len > 0);
err = paranoid_check_not_bad(ubi, pnum);
if (err)
return err > 0 ? -EINVAL : err;
addr = (loff_t)pnum * ubi->peb_size + offset;
retry:
err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
if (err) {
if (err == -EUCLEAN) {
/*
* -EUCLEAN is reported if there was a bit-flip which
* was corrected, so this is harmless.
*/
ubi_msg("fixable bit-flip detected at PEB %d", pnum);
ubi_assert(len == read);
return UBI_IO_BITFLIPS;
}
if (read != len && retries++ < UBI_IO_RETRIES) {
dbg_io("error %d while reading %d bytes from PEB %d:%d, "
"read only %zd bytes, retry",
err, len, pnum, offset, read);
yield();
goto retry;
}
ubi_err("error %d while reading %d bytes from PEB %d:%d, "
"read %zd bytes", err, len, pnum, offset, read);
ubi_dbg_dump_stack();
} else {
ubi_assert(len == read);
if (ubi_dbg_is_bitflip()) {
dbg_msg("bit-flip (emulated)");
err = UBI_IO_BITFLIPS;
}
}
return err;
}
/**
* ubi_io_write - write data to a physical eraseblock.
* @ubi: UBI device description object
* @buf: buffer with the data to write
* @pnum: physical eraseblock number to write to
* @offset: offset within the physical eraseblock where to write
* @len: how many bytes to write
*
* This function writes @len bytes of data from buffer @buf to offset @offset
* of physical eraseblock @pnum. If all the data were successfully written,
* zero is returned. If an error occurred, this function returns a negative
* error code. If %-EIO is returned, the physical eraseblock most probably went
* bad.
*
* Note, in case of an error, it is possible that something was still written
* to the flash media, but may be some garbage.
*/
int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
int len)
{
int err;
size_t written;
loff_t addr;
dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
ubi_assert(offset % ubi->hdrs_min_io_size == 0);
ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
if (ubi->ro_mode) {
ubi_err("read-only mode");
return -EROFS;
}
/* The below has to be compiled out if paranoid checks are disabled */
err = paranoid_check_not_bad(ubi, pnum);
if (err)
return err > 0 ? -EINVAL : err;
/* The area we are writing to has to contain all 0xFF bytes */
err = paranoid_check_all_ff(ubi, pnum, offset, len);
if (err)
return err > 0 ? -EINVAL : err;
if (offset >= ubi->leb_start) {
/*
* We write to the data area of the physical eraseblock. Make
* sure it has valid EC and VID headers.
*/
err = paranoid_check_peb_ec_hdr(ubi, pnum);
if (err)
return err > 0 ? -EINVAL : err;
err = paranoid_check_peb_vid_hdr(ubi, pnum);
if (err)
return err > 0 ? -EINVAL : err;
}
if (ubi_dbg_is_write_failure()) {
dbg_err("cannot write %d bytes to PEB %d:%d "
"(emulated)", len, pnum, offset);
ubi_dbg_dump_stack();
return -EIO;
}
addr = (loff_t)pnum * ubi->peb_size + offset;
err = ubi->mtd->write(ubi->mtd, addr, len, &written, buf);
if (err) {
ubi_err("error %d while writing %d bytes to PEB %d:%d, written"
" %zd bytes", err, len, pnum, offset, written);
ubi_dbg_dump_stack();
} else
ubi_assert(written == len);
return err;
}
/**
* erase_callback - MTD erasure call-back.
* @ei: MTD erase information object.
*
* Note, even though MTD erase interface is asynchronous, all the current
* implementations are synchronous anyway.
*/
static void erase_callback(struct erase_info *ei)
{
wake_up_interruptible((wait_queue_head_t *)ei->priv);
}
/**
* do_sync_erase - synchronously erase a physical eraseblock.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to erase
*
* This function synchronously erases physical eraseblock @pnum and returns
* zero in case of success and a negative error code in case of failure. If
* %-EIO is returned, the physical eraseblock most probably went bad.
*/
static int do_sync_erase(struct ubi_device *ubi, int pnum)
{
int err, retries = 0;
struct erase_info ei;
wait_queue_head_t wq;
dbg_io("erase PEB %d", pnum);
retry:
init_waitqueue_head(&wq);
memset(&ei, 0, sizeof(struct erase_info));
ei.mtd = ubi->mtd;
ei.addr = (loff_t)pnum * ubi->peb_size;
ei.len = ubi->peb_size;
ei.callback = erase_callback;
ei.priv = (unsigned long)&wq;
err = ubi->mtd->erase(ubi->mtd, &ei);
if (err) {
if (retries++ < UBI_IO_RETRIES) {
dbg_io("error %d while erasing PEB %d, retry",
err, pnum);
yield();
goto retry;
}
ubi_err("cannot erase PEB %d, error %d", pnum, err);
ubi_dbg_dump_stack();
return err;
}
err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
ei.state == MTD_ERASE_FAILED);
if (err) {
ubi_err("interrupted PEB %d erasure", pnum);
return -EINTR;
}
if (ei.state == MTD_ERASE_FAILED) {
if (retries++ < UBI_IO_RETRIES) {
dbg_io("error while erasing PEB %d, retry", pnum);
yield();
goto retry;
}
ubi_err("cannot erase PEB %d", pnum);
ubi_dbg_dump_stack();
return -EIO;
}
err = paranoid_check_all_ff(ubi, pnum, 0, ubi->peb_size);
if (err)
return err > 0 ? -EINVAL : err;
if (ubi_dbg_is_erase_failure() && !err) {
dbg_err("cannot erase PEB %d (emulated)", pnum);
return -EIO;
}
return 0;
}
/**
* check_pattern - check if buffer contains only a certain byte pattern.
* @buf: buffer to check
* @patt: the pattern to check
* @size: buffer size in bytes
*
* This function returns %1 in there are only @patt bytes in @buf, and %0 if
* something else was also found.
*/
static int check_pattern(const void *buf, uint8_t patt, int size)
{
int i;
for (i = 0; i < size; i++)
if (((const uint8_t *)buf)[i] != patt)
return 0;
return 1;
}
/* Patterns to write to a physical eraseblock when torturing it */
static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
/**
* torture_peb - test a supposedly bad physical eraseblock.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to test
*
* This function returns %-EIO if the physical eraseblock did not pass the
* test, a positive number of erase operations done if the test was
* successfully passed, and other negative error codes in case of other errors.
*/
static int torture_peb(struct ubi_device *ubi, int pnum)
{
int err, i, patt_count;
patt_count = ARRAY_SIZE(patterns);
ubi_assert(patt_count > 0);
mutex_lock(&ubi->buf_mutex);
for (i = 0; i < patt_count; i++) {
err = do_sync_erase(ubi, pnum);
if (err)
goto out;
/* Make sure the PEB contains only 0xFF bytes */
err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
if (err)
goto out;
err = check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
if (err == 0) {
ubi_err("erased PEB %d, but a non-0xFF byte found",
pnum);
err = -EIO;
goto out;
}
/* Write a pattern and check it */
memset(ubi->peb_buf1, patterns[i], ubi->peb_size);
err = ubi_io_write(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
if (err)
goto out;
memset(ubi->peb_buf1, ~patterns[i], ubi->peb_size);
err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
if (err)
goto out;
err = check_pattern(ubi->peb_buf1, patterns[i], ubi->peb_size);
if (err == 0) {
ubi_err("pattern %x checking failed for PEB %d",
patterns[i], pnum);
err = -EIO;
goto out;
}
}
err = patt_count;
out:
mutex_unlock(&ubi->buf_mutex);
if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
/*
* If a bit-flip or data integrity error was detected, the test
* has not passed because it happened on a freshly erased
* physical eraseblock which means something is wrong with it.
*/
ubi_err("read problems on freshly erased PEB %d, must be bad",
pnum);
err = -EIO;
}
return err;
}
/**
* ubi_io_sync_erase - synchronously erase a physical eraseblock.
* @ubi: UBI device description object
* @pnum: physical eraseblock number to erase
* @torture: if this physical eraseblock has to be tortured
*
* This function synchronously erases physical eraseblock @pnum. If @torture
* flag is not zero, the physical eraseblock is checked by means of writing
* different patterns to it and reading them back. If the torturing is enabled,
* the physical eraseblock is erased more then once.
*
* This function returns the number of erasures made in case of success, %-EIO
* if the erasure failed or the torturing test failed, and other negative error
* codes in case of other errors. Note, %-EIO means that the physical
* eraseblock is bad.
*/
int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
{
int err, ret = 0;
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
err = paranoid_check_not_bad(ubi, pnum);
if (err != 0)
return err > 0 ? -EINVAL : err;
if (ubi->ro_mode) {
ubi_err("read-only mode");
return -EROFS;
}
if (torture) {
ret = torture_peb(ubi, pnum);
if (ret < 0)
return ret;
}
err = do_sync_erase(ubi, pnum);
if (err)
return err;
return ret + 1;
}
/**
* ubi_io_is_bad - check if a physical eraseblock is bad.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to check
*
* This function returns a positive number if the physical eraseblock is bad,
* zero if not, and a negative error code if an error occurred.
*/
int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
{
struct mtd_info *mtd = ubi->mtd;
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
if (ubi->bad_allowed) {
int ret;
ret = mtd->block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
if (ret < 0)
ubi_err("error %d while checking if PEB %d is bad",
ret, pnum);
else if (ret)
dbg_io("PEB %d is bad", pnum);
return ret;
}
return 0;
}
/**
* ubi_io_mark_bad - mark a physical eraseblock as bad.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to mark
*
* This function returns zero in case of success and a negative error code in
* case of failure.
*/
int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
{
int err;
struct mtd_info *mtd = ubi->mtd;
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
if (ubi->ro_mode) {
ubi_err("read-only mode");
return -EROFS;
}
if (!ubi->bad_allowed)
return 0;
err = mtd->block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
if (err)
ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
return err;
}
/**
* validate_ec_hdr - validate an erase counter header.
* @ubi: UBI device description object
* @ec_hdr: the erase counter header to check
*
* This function returns zero if the erase counter header is OK, and %1 if
* not.
*/
static int validate_ec_hdr(const struct ubi_device *ubi,
const struct ubi_ec_hdr *ec_hdr)
{
long long ec;
int vid_hdr_offset, leb_start;
ec = be64_to_cpu(ec_hdr->ec);
vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
leb_start = be32_to_cpu(ec_hdr->data_offset);
if (ec_hdr->version != UBI_VERSION) {
ubi_err("node with incompatible UBI version found: "
"this UBI version is %d, image version is %d",
UBI_VERSION, (int)ec_hdr->version);
goto bad;
}
if (vid_hdr_offset != ubi->vid_hdr_offset) {
ubi_err("bad VID header offset %d, expected %d",
vid_hdr_offset, ubi->vid_hdr_offset);
goto bad;
}
if (leb_start != ubi->leb_start) {
ubi_err("bad data offset %d, expected %d",
leb_start, ubi->leb_start);
goto bad;
}
if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
ubi_err("bad erase counter %lld", ec);
goto bad;
}
return 0;
bad:
ubi_err("bad EC header");
ubi_dbg_dump_ec_hdr(ec_hdr);
ubi_dbg_dump_stack();
return 1;
}
/**
* ubi_io_read_ec_hdr - read and check an erase counter header.
* @ubi: UBI device description object
* @pnum: physical eraseblock to read from
* @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
* header
* @verbose: be verbose if the header is corrupted or was not found
*
* This function reads erase counter header from physical eraseblock @pnum and
* stores it in @ec_hdr. This function also checks CRC checksum of the read
* erase counter header. The following codes may be returned:
*
* o %0 if the CRC checksum is correct and the header was successfully read;
* o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
* and corrected by the flash driver; this is harmless but may indicate that
* this eraseblock may become bad soon (but may be not);
* o %UBI_IO_BAD_EC_HDR if the erase counter header is corrupted (a CRC error);
* o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
* o a negative error code in case of failure.
*/
int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
struct ubi_ec_hdr *ec_hdr, int verbose)
{
int err, read_err = 0;
uint32_t crc, magic, hdr_crc;
dbg_io("read EC header from PEB %d", pnum);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
if (err) {
if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
return err;
/*
* We read all the data, but either a correctable bit-flip
* occurred, or MTD reported about some data integrity error,
* like an ECC error in case of NAND. The former is harmless,
* the later may mean that the read data is corrupted. But we
* have a CRC check-sum and we will detect this. If the EC
* header is still OK, we just report this as there was a
* bit-flip.
*/
read_err = err;
}
magic = be32_to_cpu(ec_hdr->magic);
if (magic != UBI_EC_HDR_MAGIC) {
/*
* The magic field is wrong. Let's check if we have read all
* 0xFF. If yes, this physical eraseblock is assumed to be
* empty.
*
* But if there was a read error, we do not test it for all
* 0xFFs. Even if it does contain all 0xFFs, this error
* indicates that something is still wrong with this physical
* eraseblock and we anyway cannot treat it as empty.
*/
if (read_err != -EBADMSG &&
check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
/* The physical eraseblock is supposedly empty */
/*
* The below is just a paranoid check, it has to be
* compiled out if paranoid checks are disabled.
*/
err = paranoid_check_all_ff(ubi, pnum, 0,
ubi->peb_size);
if (err)
return err > 0 ? UBI_IO_BAD_EC_HDR : err;
if (verbose)
ubi_warn("no EC header found at PEB %d, "
"only 0xFF bytes", pnum);
return UBI_IO_PEB_EMPTY;
}
/*
* This is not a valid erase counter header, and these are not
* 0xFF bytes. Report that the header is corrupted.
*/
if (verbose) {
ubi_warn("bad magic number at PEB %d: %08x instead of "
"%08x", pnum, magic, UBI_EC_HDR_MAGIC);
ubi_dbg_dump_ec_hdr(ec_hdr);
}
return UBI_IO_BAD_EC_HDR;
}
crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
if (hdr_crc != crc) {
if (verbose) {
ubi_warn("bad EC header CRC at PEB %d, calculated %#08x,"
" read %#08x", pnum, crc, hdr_crc);
ubi_dbg_dump_ec_hdr(ec_hdr);
}
return UBI_IO_BAD_EC_HDR;
}
/* And of course validate what has just been read from the media */
err = validate_ec_hdr(ubi, ec_hdr);
if (err) {
ubi_err("validation failed for PEB %d", pnum);
return -EINVAL;
}
return read_err ? UBI_IO_BITFLIPS : 0;
}
/**
* ubi_io_write_ec_hdr - write an erase counter header.
* @ubi: UBI device description object
* @pnum: physical eraseblock to write to
* @ec_hdr: the erase counter header to write
*
* This function writes erase counter header described by @ec_hdr to physical
* eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
* the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
* field.
*
* This function returns zero in case of success and a negative error code in
* case of failure. If %-EIO is returned, the physical eraseblock most probably
* went bad.
*/
int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
struct ubi_ec_hdr *ec_hdr)
{
int err;
uint32_t crc;
dbg_io("write EC header to PEB %d", pnum);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
ec_hdr->version = UBI_VERSION;
ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
ec_hdr->hdr_crc = cpu_to_be32(crc);
err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
if (err)
return -EINVAL;
err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
return err;
}
/**
* validate_vid_hdr - validate a volume identifier header.
* @ubi: UBI device description object
* @vid_hdr: the volume identifier header to check
*
* This function checks that data stored in the volume identifier header
* @vid_hdr. Returns zero if the VID header is OK and %1 if not.
*/
static int validate_vid_hdr(const struct ubi_device *ubi,
const struct ubi_vid_hdr *vid_hdr)
{
int vol_type = vid_hdr->vol_type;
int copy_flag = vid_hdr->copy_flag;
int vol_id = be32_to_cpu(vid_hdr->vol_id);
int lnum = be32_to_cpu(vid_hdr->lnum);
int compat = vid_hdr->compat;
int data_size = be32_to_cpu(vid_hdr->data_size);
int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
int data_pad = be32_to_cpu(vid_hdr->data_pad);
int data_crc = be32_to_cpu(vid_hdr->data_crc);
int usable_leb_size = ubi->leb_size - data_pad;
if (copy_flag != 0 && copy_flag != 1) {
dbg_err("bad copy_flag");
goto bad;
}
if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
data_pad < 0) {
dbg_err("negative values");
goto bad;
}
if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
dbg_err("bad vol_id");
goto bad;
}
if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
dbg_err("bad compat");
goto bad;
}
if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
compat != UBI_COMPAT_REJECT) {
dbg_err("bad compat");
goto bad;
}
if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
dbg_err("bad vol_type");
goto bad;
}
if (data_pad >= ubi->leb_size / 2) {
dbg_err("bad data_pad");
goto bad;
}
if (vol_type == UBI_VID_STATIC) {
/*
* Although from high-level point of view static volumes may
* contain zero bytes of data, but no VID headers can contain
* zero at these fields, because they empty volumes do not have
* mapped logical eraseblocks.
*/
if (used_ebs == 0) {
dbg_err("zero used_ebs");
goto bad;
}
if (data_size == 0) {
dbg_err("zero data_size");
goto bad;
}
if (lnum < used_ebs - 1) {
if (data_size != usable_leb_size) {
dbg_err("bad data_size");
goto bad;
}
} else if (lnum == used_ebs - 1) {
if (data_size == 0) {
dbg_err("bad data_size at last LEB");
goto bad;
}
} else {
dbg_err("too high lnum");
goto bad;
}
} else {
if (copy_flag == 0) {
if (data_crc != 0) {
dbg_err("non-zero data CRC");
goto bad;
}
if (data_size != 0) {
dbg_err("non-zero data_size");
goto bad;
}
} else {
if (data_size == 0) {
dbg_err("zero data_size of copy");
goto bad;
}
}
if (used_ebs != 0) {
dbg_err("bad used_ebs");
goto bad;
}
}
return 0;
bad:
ubi_err("bad VID header");
ubi_dbg_dump_vid_hdr(vid_hdr);
ubi_dbg_dump_stack();
return 1;
}
/**
* ubi_io_read_vid_hdr - read and check a volume identifier header.
* @ubi: UBI device description object
* @pnum: physical eraseblock number to read from
* @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
* identifier header
* @verbose: be verbose if the header is corrupted or wasn't found
*
* This function reads the volume identifier header from physical eraseblock
* @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
* volume identifier header. The following codes may be returned:
*
* o %0 if the CRC checksum is correct and the header was successfully read;
* o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
* and corrected by the flash driver; this is harmless but may indicate that
* this eraseblock may become bad soon;
* o %UBI_IO_BAD_VID_HRD if the volume identifier header is corrupted (a CRC
* error detected);
* o %UBI_IO_PEB_FREE if the physical eraseblock is free (i.e., there is no VID
* header there);
* o a negative error code in case of failure.
*/
int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
struct ubi_vid_hdr *vid_hdr, int verbose)
{
int err, read_err = 0;
uint32_t crc, magic, hdr_crc;
void *p;
dbg_io("read VID header from PEB %d", pnum);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
p = (char *)vid_hdr - ubi->vid_hdr_shift;
err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
ubi->vid_hdr_alsize);
if (err) {
if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
return err;
/*
* We read all the data, but either a correctable bit-flip
* occurred, or MTD reported about some data integrity error,
* like an ECC error in case of NAND. The former is harmless,
* the later may mean the read data is corrupted. But we have a
* CRC check-sum and we will identify this. If the VID header is
* still OK, we just report this as there was a bit-flip.
*/
read_err = err;
}
magic = be32_to_cpu(vid_hdr->magic);
if (magic != UBI_VID_HDR_MAGIC) {
/*
* If we have read all 0xFF bytes, the VID header probably does
* not exist and the physical eraseblock is assumed to be free.
*
* But if there was a read error, we do not test the data for
* 0xFFs. Even if it does contain all 0xFFs, this error
* indicates that something is still wrong with this physical
* eraseblock and it cannot be regarded as free.
*/
if (read_err != -EBADMSG &&
check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
/* The physical eraseblock is supposedly free */
/*
* The below is just a paranoid check, it has to be
* compiled out if paranoid checks are disabled.
*/
err = paranoid_check_all_ff(ubi, pnum, ubi->leb_start,
ubi->leb_size);
if (err)
return err > 0 ? UBI_IO_BAD_VID_HDR : err;
if (verbose)
ubi_warn("no VID header found at PEB %d, "
"only 0xFF bytes", pnum);
return UBI_IO_PEB_FREE;
}
/*
* This is not a valid VID header, and these are not 0xFF
* bytes. Report that the header is corrupted.
*/
if (verbose) {
ubi_warn("bad magic number at PEB %d: %08x instead of "
"%08x", pnum, magic, UBI_VID_HDR_MAGIC);
ubi_dbg_dump_vid_hdr(vid_hdr);
}
return UBI_IO_BAD_VID_HDR;
}
crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
if (hdr_crc != crc) {
if (verbose) {
ubi_warn("bad CRC at PEB %d, calculated %#08x, "
"read %#08x", pnum, crc, hdr_crc);
ubi_dbg_dump_vid_hdr(vid_hdr);
}
return UBI_IO_BAD_VID_HDR;
}
/* Validate the VID header that we have just read */
err = validate_vid_hdr(ubi, vid_hdr);
if (err) {
ubi_err("validation failed for PEB %d", pnum);
return -EINVAL;
}
return read_err ? UBI_IO_BITFLIPS : 0;
}
/**
* ubi_io_write_vid_hdr - write a volume identifier header.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to write to
* @vid_hdr: the volume identifier header to write
*
* This function writes the volume identifier header described by @vid_hdr to
* physical eraseblock @pnum. This function automatically fills the
* @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
* header CRC checksum and stores it at vid_hdr->hdr_crc.
*
* This function returns zero in case of success and a negative error code in
* case of failure. If %-EIO is returned, the physical eraseblock probably went
* bad.
*/
int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
struct ubi_vid_hdr *vid_hdr)
{
int err;
uint32_t crc;
void *p;
dbg_io("write VID header to PEB %d", pnum);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
err = paranoid_check_peb_ec_hdr(ubi, pnum);
if (err)
return err > 0 ? -EINVAL: err;
vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
vid_hdr->version = UBI_VERSION;
crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
vid_hdr->hdr_crc = cpu_to_be32(crc);
err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
if (err)
return -EINVAL;
p = (char *)vid_hdr - ubi->vid_hdr_shift;
err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
ubi->vid_hdr_alsize);
return err;
}
#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
/**
* paranoid_check_not_bad - ensure that a physical eraseblock is not bad.
* @ubi: UBI device description object
* @pnum: physical eraseblock number to check
*
* This function returns zero if the physical eraseblock is good, a positive
* number if it is bad and a negative error code if an error occurred.
*/
static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum)
{
int err;
err = ubi_io_is_bad(ubi, pnum);
if (!err)
return err;
ubi_err("paranoid check failed for PEB %d", pnum);
ubi_dbg_dump_stack();
return err;
}
/**
* paranoid_check_ec_hdr - check if an erase counter header is all right.
* @ubi: UBI device description object
* @pnum: physical eraseblock number the erase counter header belongs to
* @ec_hdr: the erase counter header to check
*
* This function returns zero if the erase counter header contains valid
* values, and %1 if not.
*/
static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_ec_hdr *ec_hdr)
{
int err;
uint32_t magic;
magic = be32_to_cpu(ec_hdr->magic);
if (magic != UBI_EC_HDR_MAGIC) {
ubi_err("bad magic %#08x, must be %#08x",
magic, UBI_EC_HDR_MAGIC);
goto fail;
}
err = validate_ec_hdr(ubi, ec_hdr);
if (err) {
ubi_err("paranoid check failed for PEB %d", pnum);
goto fail;
}
return 0;
fail:
ubi_dbg_dump_ec_hdr(ec_hdr);
ubi_dbg_dump_stack();
return 1;
}
/**
* paranoid_check_peb_ec_hdr - check that the erase counter header of a
* physical eraseblock is in-place and is all right.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to check
*
* This function returns zero if the erase counter header is all right, %1 if
* not, and a negative error code if an error occurred.
*/
static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
{
int err;
uint32_t crc, hdr_crc;
struct ubi_ec_hdr *ec_hdr;
ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
if (!ec_hdr)
return -ENOMEM;
err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
goto exit;
crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
if (hdr_crc != crc) {
ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
ubi_err("paranoid check failed for PEB %d", pnum);
ubi_dbg_dump_ec_hdr(ec_hdr);
ubi_dbg_dump_stack();
err = 1;
goto exit;
}
err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
exit:
kfree(ec_hdr);
return err;
}
/**
* paranoid_check_vid_hdr - check that a volume identifier header is all right.
* @ubi: UBI device description object
* @pnum: physical eraseblock number the volume identifier header belongs to
* @vid_hdr: the volume identifier header to check
*
* This function returns zero if the volume identifier header is all right, and
* %1 if not.
*/
static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_vid_hdr *vid_hdr)
{
int err;
uint32_t magic;
magic = be32_to_cpu(vid_hdr->magic);
if (magic != UBI_VID_HDR_MAGIC) {
ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
magic, pnum, UBI_VID_HDR_MAGIC);
goto fail;
}
err = validate_vid_hdr(ubi, vid_hdr);
if (err) {
ubi_err("paranoid check failed for PEB %d", pnum);
goto fail;
}
return err;
fail:
ubi_err("paranoid check failed for PEB %d", pnum);
ubi_dbg_dump_vid_hdr(vid_hdr);
ubi_dbg_dump_stack();
return 1;
}
/**
* paranoid_check_peb_vid_hdr - check that the volume identifier header of a
* physical eraseblock is in-place and is all right.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to check
*
* This function returns zero if the volume identifier header is all right,
* %1 if not, and a negative error code if an error occurred.
*/
static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
{
int err;
uint32_t crc, hdr_crc;
struct ubi_vid_hdr *vid_hdr;
void *p;
vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
if (!vid_hdr)
return -ENOMEM;
p = (char *)vid_hdr - ubi->vid_hdr_shift;
err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
ubi->vid_hdr_alsize);
if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
goto exit;
crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
if (hdr_crc != crc) {
ubi_err("bad VID header CRC at PEB %d, calculated %#08x, "
"read %#08x", pnum, crc, hdr_crc);
ubi_err("paranoid check failed for PEB %d", pnum);
ubi_dbg_dump_vid_hdr(vid_hdr);
ubi_dbg_dump_stack();
err = 1;
goto exit;
}
err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
exit:
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}
/**
* paranoid_check_all_ff - check that a region of flash is empty.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to check
* @offset: the starting offset within the physical eraseblock to check
* @len: the length of the region to check
*
* This function returns zero if only 0xFF bytes are present at offset
* @offset of the physical eraseblock @pnum, %1 if not, and a negative error
* code if an error occurred.
*/
static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
int len)
{
size_t read;
int err;
loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
mutex_lock(&ubi->dbg_buf_mutex);
err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf);
if (err && err != -EUCLEAN) {
ubi_err("error %d while reading %d bytes from PEB %d:%d, "
"read %zd bytes", err, len, pnum, offset, read);
goto error;
}
err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
if (err == 0) {
ubi_err("flash region at PEB %d:%d, length %d does not "
"contain all 0xFF bytes", pnum, offset, len);
goto fail;
}
mutex_unlock(&ubi->dbg_buf_mutex);
return 0;
fail:
ubi_err("paranoid check failed for PEB %d", pnum);
dbg_msg("hex dump of the %d-%d region", offset, offset + len);
print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
ubi->dbg_peb_buf, len, 1);
err = 1;
error:
ubi_dbg_dump_stack();
mutex_unlock(&ubi->dbg_buf_mutex);
return err;
}
#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */
