/**
* ubi_check_volume - check the contents of a static volume.
* @ubi: UBI device description object
* @vol_id: ID of the volume to check
*
* This function checks if static volume @vol_id is corrupted by fully reading
* it and checking data CRC. This function returns %0 if the volume is not
* corrupted, %1 if it is corrupted and a negative error code in case of
* failure. Dynamic volumes are not checked and zero is returned immediately.
*/
int ubi_check_volume(struct ubi_device *ubi, int vol_id)
{
void *buf;
int err = 0, i;
struct ubi_volume *vol = ubi->volumes[vol_id];
WATCHDOG_RESET();
if (vol->vol_type != UBI_STATIC_VOLUME)
return 0;
buf = vmalloc(vol->usable_leb_size);
if (!buf)
return -ENOMEM;
for (i = 0; i < vol->used_ebs; i++) {
int size;
if (i == vol->used_ebs - 1)
size = vol->last_eb_bytes;
else
size = vol->usable_leb_size;
err = ubi_eba_read_leb(ubi, vol, i, buf, 0, size, 1);
if (err) {
if (mtd_is_eccerr(err))
err = 1;
break;
}
}
vfree(buf);
return err;
}
/**
* self_check_peb_ec_hdr - check erase counter header.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to check
*
* This function returns zero if the erase counter header is all right and and
* a negative error code if not or if an error occurred.
*/
static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
{
int err;
uint32_t crc, hdr_crc;
struct ubi_ec_hdr *ec_hdr;
if (!ubi_dbg_chk_io(ubi))
return 0;
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 && !mtd_is_eccerr(err))
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(ubi, "bad CRC, calculated %#08x, read %#08x",
crc, hdr_crc);
ubi_err(ubi, "self-check failed for PEB %d", pnum);
ubi_dump_ec_hdr(ec_hdr);
dump_stack();
err = -EINVAL;
goto exit;
}
err = self_check_ec_hdr(ubi, pnum, ec_hdr);
exit:
kfree(ec_hdr);
return err;
}
static int
concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
{
struct mtd_concat *concat = CONCAT(mtd);
struct mtd_oob_ops devops = *ops;
int i, err, ret = 0;
ops->retlen = ops->oobretlen = 0;
for (i = 0; i < concat->num_subdev; i++) {
struct mtd_info *subdev = concat->subdev[i];
if (from >= subdev->size) {
from -= subdev->size;
continue;
}
/* partial read ? */
if (from + devops.len > subdev->size)
devops.len = subdev->size - from;
err = subdev->read_oob(subdev, from, &devops);
ops->retlen += devops.retlen;
ops->oobretlen += devops.oobretlen;
/* Save information about bitflips! */
if (unlikely(err)) {
if (mtd_is_eccerr(err)) {
mtd->ecc_stats.failed++;
ret = err;
} else if (mtd_is_bitflip(err)) {
mtd->ecc_stats.corrected++;
/* Do not overwrite -EBADMSG !! */
if (!ret)
ret = err;
} else
return err;
}
if (devops.datbuf) {
devops.len = ops->len - ops->retlen;
if (!devops.len)
return ret;
devops.datbuf += devops.retlen;
}
if (devops.oobbuf) {
devops.ooblen = ops->ooblen - ops->oobretlen;
if (!devops.ooblen)
return ret;
devops.oobbuf += ops->oobretlen;
}
from = 0;
}
return -EINVAL;
}
static int
concat_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t * retlen, u_char * buf)
{
struct mtd_concat *concat = CONCAT(mtd);
int ret = 0, err;
int i;
#ifdef __UBOOT__
*retlen = 0;
#endif
for (i = 0; i < concat->num_subdev; i++) {
struct mtd_info *subdev = concat->subdev[i];
size_t size, retsize;
if (from >= subdev->size) {
/* Not destined for this subdev */
size = 0;
from -= subdev->size;
continue;
}
if (from + len > subdev->size)
/* First part goes into this subdev */
size = subdev->size - from;
else
/* Entire transaction goes into this subdev */
size = len;
err = mtd_read(subdev, from, size, &retsize, buf);
/* Save information about bitflips! */
if (unlikely(err)) {
if (mtd_is_eccerr(err)) {
mtd->ecc_stats.failed++;
ret = err;
} else if (mtd_is_bitflip(err)) {
mtd->ecc_stats.corrected++;
/* Do not overwrite -EBADMSG !! */
if (!ret)
ret = err;
} else
return err;
}
*retlen += retsize;
len -= size;
if (len == 0)
return ret;
buf += size;
from = 0;
}
return -EINVAL;
}
static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct mtd_part *part = PART(mtd);
struct mtd_ecc_stats stats;
int res;
stats = part->master->ecc_stats;
res = mtd_read(part->master, from + part->offset, len, retlen, buf);
if (unlikely(res)) {
if (mtd_is_bitflip(res))
mtd->ecc_stats.corrected += part->master->ecc_stats.corrected - stats.corrected;
if (mtd_is_eccerr(res))
mtd->ecc_stats.failed += part->master->ecc_stats.failed - stats.failed;
}
return res;
}
static int part_read_oob(struct mtd_info *mtd, loff_t from,
struct mtd_oob_ops *ops)
{
struct mtd_part *part = PART(mtd);
int res;
if (from >= mtd->size)
return -EINVAL;
if (ops->datbuf && from + ops->len > mtd->size)
return -EINVAL;
res = mtd_read_oob(part->master, from + part->offset, ops);
if (unlikely(res)) {
if (mtd_is_bitflip(res))
mtd->ecc_stats.corrected++;
if (mtd_is_eccerr(res))
mtd->ecc_stats.failed++;
}
return res;
}
/**
* self_check_peb_vid_hdr - check volume identifier header.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to check
*
* This function returns zero if the volume identifier header is all right,
* and a negative error code if not or if an error occurred.
*/
static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
{
int err;
uint32_t crc, hdr_crc;
struct ubi_vid_io_buf *vidb;
struct ubi_vid_hdr *vid_hdr;
void *p;
if (!ubi_dbg_chk_io(ubi))
return 0;
vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
if (!vidb)
return -ENOMEM;
vid_hdr = ubi_get_vid_hdr(vidb);
p = vidb->buffer;
err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
ubi->vid_hdr_alsize);
if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
goto exit;
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) {
ubi_err(ubi, "bad VID header CRC at PEB %d, calculated %#08x, read %#08x",
pnum, crc, hdr_crc);
ubi_err(ubi, "self-check failed for PEB %d", pnum);
ubi_dump_vid_hdr(vid_hdr);
dump_stack();
err = -EINVAL;
goto exit;
}
err = self_check_vid_hdr(ubi, pnum, vid_hdr);
exit:
ubi_free_vid_buf(vidb);
return err;
}
/**
* paranoid_check_peb_vid_hdr - check volume identifier header.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to check
*
* This function returns zero if the volume identifier header is all right,
* and a negative error code if not or 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;
if (!ubi->dbg->chk_io)
return 0;
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 && !mtd_is_eccerr(err))
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 = -EINVAL;
goto exit;
}
err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
exit:
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}
/**
* ubi_leb_read_sg - read data into a scatter gather list.
* @desc: volume descriptor
* @lnum: logical eraseblock number to read from
* @buf: buffer where to store the read data
* @offset: offset within the logical eraseblock to read from
* @len: how many bytes to read
* @check: whether UBI has to check the read data's CRC or not.
*
* This function works exactly like ubi_leb_read_sg(). But instead of
* storing the read data into a buffer it writes to an UBI scatter gather
* list.
*/
int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
int offset, int len, int check)
{
struct ubi_volume *vol = desc->vol;
struct ubi_device *ubi = vol->ubi;
int err, vol_id = vol->vol_id;
dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
err = leb_read_sanity_check(desc, lnum, offset, len);
if (err < 0)
return err;
if (len == 0)
return 0;
err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
vol->corrupted = 1;
}
return err;
}
/**
* ubi_leb_read - read data.
* @desc: volume descriptor
* @lnum: logical eraseblock number to read from
* @buf: buffer where to store the read data
* @offset: offset within the logical eraseblock to read from
* @len: how many bytes to read
* @check: whether UBI has to check the read data's CRC or not.
*
* This function reads data from offset @offset of logical eraseblock @lnum and
* stores the data at @buf. When reading from static volumes, @check specifies
* whether the data has to be checked or not. If yes, the whole logical
* eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
* checksum is per-eraseblock). So checking may substantially slow down the
* read speed. The @check argument is ignored for dynamic volumes.
*
* In case of success, this function returns zero. In case of failure, this
* function returns a negative error code.
*
* %-EBADMSG error code is returned:
* o for both static and dynamic volumes if MTD driver has detected a data
* integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
* o for static volumes in case of data CRC mismatch.
*
* If the volume is damaged because of an interrupted update this function just
* returns immediately with %-EBADF error code.
*/
int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
int len, int check)
{
struct ubi_volume *vol = desc->vol;
struct ubi_device *ubi = vol->ubi;
int err, vol_id = vol->vol_id;
dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
lnum >= vol->used_ebs || offset < 0 || len < 0 ||
offset + len > vol->usable_leb_size)
return -EINVAL;
if (vol->vol_type == UBI_STATIC_VOLUME) {
if (vol->used_ebs == 0)
/* Empty static UBI volume */
return 0;
if (lnum == vol->used_ebs - 1 &&
offset + len > vol->last_eb_bytes)
return -EINVAL;
}
if (vol->upd_marker)
return -EBADF;
if (len == 0)
return 0;
err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
ubi_warn(ubi->ubi_num, "mark volume %d as corrupted", vol_id);
vol->corrupted = 1;
}
return err;
}
/**
* compare_lebs - find out which logical eraseblock is newer.
* @ubi: UBI device description object
* @seb: first logical eraseblock to compare
* @pnum: physical eraseblock number of the second logical eraseblock to
* compare
* @vid_hdr: volume identifier header of the second logical eraseblock
*
* This function compares 2 copies of a LEB and informs which one is newer. In
* case of success this function returns a positive value, in case of failure, a
* negative error code is returned. The success return codes use the following
* bits:
* o bit 0 is cleared: the first PEB (described by @seb) is newer than the
* second PEB (described by @pnum and @vid_hdr);
* o bit 0 is set: the second PEB is newer;
* o bit 1 is cleared: no bit-flips were detected in the newer LEB;
* o bit 1 is set: bit-flips were detected in the newer LEB;
* o bit 2 is cleared: the older LEB is not corrupted;
* o bit 2 is set: the older LEB is corrupted.
*/
static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
int pnum, const struct ubi_vid_hdr *vid_hdr)
{
void *buf;
int len, err, second_is_newer, bitflips = 0, corrupted = 0;
uint32_t data_crc, crc;
struct ubi_vid_hdr *vh = NULL;
unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
if (sqnum2 == seb->sqnum) {
/*
* This must be a really ancient UBI image which has been
* created before sequence numbers support has been added. At
* that times we used 32-bit LEB versions stored in logical
* eraseblocks. That was before UBI got into mainline. We do not
* support these images anymore. Well, those images still work,
* but only if no unclean reboots happened.
*/
ubi_err("unsupported on-flash UBI format\n");
return -EINVAL;
}
/* Obviously the LEB with lower sequence counter is older */
second_is_newer = !!(sqnum2 > seb->sqnum);
/*
* Now we know which copy is newer. If the copy flag of the PEB with
* newer version is not set, then we just return, otherwise we have to
* check data CRC. For the second PEB we already have the VID header,
* for the first one - we'll need to re-read it from flash.
*
* Note: this may be optimized so that we wouldn't read twice.
*/
if (second_is_newer) {
if (!vid_hdr->copy_flag) {
/* It is not a copy, so it is newer */
dbg_bld("second PEB %d is newer, copy_flag is unset",
pnum);
return 1;
}
} else {
if (!seb->copy_flag) {
/* It is not a copy, so it is newer */
dbg_bld("first PEB %d is newer, copy_flag is unset",
pnum);
return bitflips << 1;
}
vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
if (!vh)
return -ENOMEM;
pnum = seb->pnum;
err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
if (err) {
if (err == UBI_IO_BITFLIPS)
bitflips = 1;
else {
dbg_err("VID of PEB %d header is bad, but it "
"was OK earlier, err %d", pnum, err);
if (err > 0)
err = -EIO;
goto out_free_vidh;
}
}
vid_hdr = vh;
}
/* Read the data of the copy and check the CRC */
len = be32_to_cpu(vid_hdr->data_size);
buf = vmalloc(len);
if (!buf) {
err = -ENOMEM;
goto out_free_vidh;
}
err = ubi_io_read_data(ubi, buf, pnum, 0, len);
if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
goto out_free_buf;
data_crc = be32_to_cpu(vid_hdr->data_crc);
crc = crc32(UBI_CRC32_INIT, buf, len);
if (crc != data_crc) {
dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
pnum, crc, data_crc);
corrupted = 1;
bitflips = 0;
second_is_newer = !second_is_newer;
} else {
dbg_bld("PEB %d CRC is OK", pnum);
bitflips = !!err;
}
vfree(buf);
ubi_free_vid_hdr(ubi, vh);
if (second_is_newer)
dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
else
dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
return second_is_newer | (bitflips << 1) | (corrupted << 2);
out_free_buf:
vfree(buf);
out_free_vidh:
ubi_free_vid_hdr(ubi, vh);
return err;
}
/**
* 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_HDR if the erase counter header is corrupted (a CRC error);
* o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
* a data integrity error (uncorrectable ECC error in case of NAND);
* o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly 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;
uint32_t crc, magic, hdr_crc;
dbg_io("read EC header from PEB %d", pnum);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
if (read_err) {
if (read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
return read_err;
/*
* We read all the data, but either a correctable bit-flip
* occurred, or MTD reported a data integrity error
* (uncorrectable 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, to force scrubbing.
*/
}
magic = be32_to_cpu(ec_hdr->magic);
if (magic != UBI_EC_HDR_MAGIC) {
if (mtd_is_eccerr(read_err))
return UBI_IO_BAD_HDR_EBADMSG;
/*
* The magic field is wrong. Let's check if we have read all
* 0xFF. If yes, this physical eraseblock is assumed to be
* empty.
*/
if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
/* The physical eraseblock is supposedly empty */
if (verbose)
ubi_warn(ubi, "no EC header found at PEB %d, only 0xFF bytes",
pnum);
dbg_bld("no EC header found at PEB %d, only 0xFF bytes",
pnum);
if (!read_err)
return UBI_IO_FF;
else
return UBI_IO_FF_BITFLIPS;
}
/*
* This is not a valid erase counter header, and these are not
* 0xFF bytes. Report that the header is corrupted.
*/
if (verbose) {
ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
pnum, magic, UBI_EC_HDR_MAGIC);
ubi_dump_ec_hdr(ec_hdr);
}
dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
pnum, magic, UBI_EC_HDR_MAGIC);
return UBI_IO_BAD_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(ubi, "bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
pnum, crc, hdr_crc);
ubi_dump_ec_hdr(ec_hdr);
}
dbg_bld("bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
pnum, crc, hdr_crc);
if (!read_err)
return UBI_IO_BAD_HDR;
else
return UBI_IO_BAD_HDR_EBADMSG;
}
/* And of course validate what has just been read from the media */
err = validate_ec_hdr(ubi, ec_hdr);
if (err) {
ubi_err(ubi, "validation failed for PEB %d", pnum);
return -EINVAL;
}
/*
* If there was %-EBADMSG, but the header CRC is still OK, report about
* a bit-flip to force scrubbing on this PEB.
*/
return read_err ? UBI_IO_BITFLIPS : 0;
}
/**
* 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;
ubi_msg(ubi, "run torture test for PEB %d", pnum);
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_buf, pnum, 0, ubi->peb_size);
if (err)
goto out;
err = ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->peb_size);
if (err == 0) {
ubi_err(ubi, "erased PEB %d, but a non-0xFF byte found",
pnum);
err = -EIO;
goto out;
}
/* Write a pattern and check it */
memset(ubi->peb_buf, patterns[i], ubi->peb_size);
err = ubi_io_write(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
if (err)
goto out;
memset(ubi->peb_buf, ~patterns[i], ubi->peb_size);
err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
if (err)
goto out;
err = ubi_check_pattern(ubi->peb_buf, patterns[i],
ubi->peb_size);
if (err == 0) {
ubi_err(ubi, "pattern %x checking failed for PEB %d",
patterns[i], pnum);
err = -EIO;
goto out;
}
}
err = patt_count;
ubi_msg(ubi, "PEB %d passed torture test, do not mark it as bad", pnum);
out:
mutex_unlock(&ubi->buf_mutex);
if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
/*
* 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(ubi, "read problems on freshly erased PEB %d, must be bad",
pnum);
err = -EIO;
}
return err;
}
/**
* 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 = self_check_not_bad(ubi, pnum);
if (err)
return err;
/*
* Deliberately corrupt the buffer to improve robustness. Indeed, if we
* do not do this, the following may happen:
* 1. The buffer contains data from previous operation, e.g., read from
* another PEB previously. The data looks like expected, e.g., if we
* just do not read anything and return - the caller would not
* notice this. E.g., if we are reading a VID header, the buffer may
* contain a valid VID header from another PEB.
* 2. The driver is buggy and returns us success or -EBADMSG or
* -EUCLEAN, but it does not actually put any data to the buffer.
*
* This may confuse UBI or upper layers - they may think the buffer
* contains valid data while in fact it is just old data. This is
* especially possible because UBI (and UBIFS) relies on CRC, and
* treats data as correct even in case of ECC errors if the CRC is
* correct.
*
* Try to prevent this situation by changing the first byte of the
* buffer.
*/
*((uint8_t *)buf) ^= 0xFF;
addr = (loff_t)pnum * ubi->peb_size + offset;
retry:
err = mtd_read(ubi->mtd, addr, len, &read, buf);
if (err) {
const char *errstr = mtd_is_eccerr(err) ? " (ECC error)" : "";
if (mtd_is_bitflip(err)) {
/*
* -EUCLEAN is reported if there was a bit-flip which
* was corrected, so this is harmless.
*
* We do not report about it here unless debugging is
* enabled. A corresponding message will be printed
* later, when it is has been scrubbed.
*/
ubi_msg(ubi, "fixable bit-flip detected at PEB %d",
pnum);
ubi_assert(len == read);
return UBI_IO_BITFLIPS;
}
if (retries++ < UBI_IO_RETRIES) {
ubi_warn(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read only %zd bytes, retry",
err, errstr, len, pnum, offset, read);
yield();
goto retry;
}
ubi_err(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read %zd bytes",
err, errstr, len, pnum, offset, read);
dump_stack();
/*
* The driver should never return -EBADMSG if it failed to read
* all the requested data. But some buggy drivers might do
* this, so we change it to -EIO.
*/
if (read != len && mtd_is_eccerr(err)) {
ubi_assert(0);
err = -EIO;
}
} else {
ubi_assert(len == read);
if (ubi_dbg_is_bitflip(ubi)) {
dbg_gen("bit-flip (emulated)");
err = UBI_IO_BITFLIPS;
}
}
return err;
}
/**
* 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 error codes are the same as in
* 'ubi_io_read_ec_hdr()'.
*
* Note, the implementation of this function is also very similar to
* 'ubi_io_read_ec_hdr()', so refer commentaries in 'ubi_io_read_ec_hdr()'.
*/
int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
struct ubi_vid_hdr *vid_hdr, int verbose)
{
int err, read_err;
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;
read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
ubi->vid_hdr_alsize);
if (read_err && read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
return read_err;
magic = be32_to_cpu(vid_hdr->magic);
if (magic != UBI_VID_HDR_MAGIC) {
if (mtd_is_eccerr(read_err))
return UBI_IO_BAD_HDR_EBADMSG;
if (ubi_check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
if (verbose)
ubi_warn(ubi, "no VID header found at PEB %d, only 0xFF bytes",
pnum);
dbg_bld("no VID header found at PEB %d, only 0xFF bytes",
pnum);
if (!read_err)
return UBI_IO_FF;
else
return UBI_IO_FF_BITFLIPS;
}
if (verbose) {
ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
pnum, magic, UBI_VID_HDR_MAGIC);
ubi_dump_vid_hdr(vid_hdr);
}
dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
pnum, magic, UBI_VID_HDR_MAGIC);
return UBI_IO_BAD_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(ubi, "bad CRC at PEB %d, calculated %#08x, read %#08x",
pnum, crc, hdr_crc);
ubi_dump_vid_hdr(vid_hdr);
}
dbg_bld("bad CRC at PEB %d, calculated %#08x, read %#08x",
pnum, crc, hdr_crc);
if (!read_err)
return UBI_IO_BAD_HDR;
else
return UBI_IO_BAD_HDR_EBADMSG;
}
err = validate_vid_hdr(ubi, vid_hdr);
if (err) {
ubi_err(ubi, "validation failed for PEB %d", pnum);
return -EINVAL;
}
return read_err ? UBI_IO_BITFLIPS : 0;
}