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linux-zen-server/drivers/mtd/ubi/io.c

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2023-08-30 17:53:23 +02:00
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) International Business Machines Corp., 2006
* Copyright (c) Nokia Corporation, 2006, 2007
*
* Author: Artem Bityutskiy (Битюцкий Артём)
*/
/*
* UBI input/output sub-system.
*
* This sub-system 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
* sub-system 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 use of 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 not relevant to the sub-page are 0xFF. So, basically,
* writing 4x512 sub-pages is 4 times slower than writing one 2KiB NAND page.
* Thus, we prefer to use sub-pages only for EC 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 sub-system 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 <linux/slab.h>
#include "ubi.h"
static int self_check_not_bad(const struct ubi_device *ubi, int pnum);
static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_ec_hdr *ec_hdr);
static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_vid_hdr *vid_hdr);
static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
int offset, int len);
/**
* 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_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(ubi, "read-only mode");
return -EROFS;
}
err = self_check_not_bad(ubi, pnum);
if (err)
return err;
/* The area we are writing to has to contain all 0xFF bytes */
err = ubi_self_check_all_ff(ubi, pnum, offset, len);
if (err)
return 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 = self_check_peb_ec_hdr(ubi, pnum);
if (err)
return err;
err = self_check_peb_vid_hdr(ubi, pnum);
if (err)
return err;
}
if (ubi_dbg_is_write_failure(ubi)) {
ubi_err(ubi, "cannot write %d bytes to PEB %d:%d (emulated)",
len, pnum, offset);
dump_stack();
return -EIO;
}
addr = (loff_t)pnum * ubi->peb_size + offset;
err = mtd_write(ubi->mtd, addr, len, &written, buf);
if (err) {
ubi_err(ubi, "error %d while writing %d bytes to PEB %d:%d, written %zd bytes",
err, len, pnum, offset, written);
dump_stack();
ubi_dump_flash(ubi, pnum, offset, len);
} else
ubi_assert(written == len);
if (!err) {
err = self_check_write(ubi, buf, pnum, offset, len);
if (err)
return err;
/*
* Since we always write sequentially, the rest of the PEB has
* to contain only 0xFF bytes.
*/
offset += len;
len = ubi->peb_size - offset;
if (len)
err = ubi_self_check_all_ff(ubi, pnum, offset, len);
}
return err;
}
/**
* 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;
dbg_io("erase PEB %d", pnum);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
if (ubi->ro_mode) {
ubi_err(ubi, "read-only mode");
return -EROFS;
}
retry:
memset(&ei, 0, sizeof(struct erase_info));
ei.addr = (loff_t)pnum * ubi->peb_size;
ei.len = ubi->peb_size;
err = mtd_erase(ubi->mtd, &ei);
if (err) {
if (retries++ < UBI_IO_RETRIES) {
ubi_warn(ubi, "error %d while erasing PEB %d, retry",
err, pnum);
yield();
goto retry;
}
ubi_err(ubi, "cannot erase PEB %d, error %d", pnum, err);
dump_stack();
return err;
}
err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
if (err)
return err;
if (ubi_dbg_is_erase_failure(ubi)) {
ubi_err(ubi, "cannot erase PEB %d (emulated)", pnum);
return -EIO;
}
return 0;
}
/* 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;
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;
}
/**
* nor_erase_prepare - prepare a NOR flash PEB for erasure.
* @ubi: UBI device description object
* @pnum: physical eraseblock number to prepare
*
* NOR flash, or at least some of them, have peculiar embedded PEB erasure
* algorithm: the PEB is first filled with zeroes, then it is erased. And
* filling with zeroes starts from the end of the PEB. This was observed with
* Spansion S29GL512N NOR flash.
*
* This means that in case of a power cut we may end up with intact data at the
* beginning of the PEB, and all zeroes at the end of PEB. In other words, the
* EC and VID headers are OK, but a large chunk of data at the end of PEB is
* zeroed. This makes UBI mistakenly treat this PEB as used and associate it
* with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
*
* This function is called before erasing NOR PEBs and it zeroes out EC and VID
* magic numbers in order to invalidate them and prevent the failures. Returns
* zero in case of success and a negative error code in case of failure.
*/
static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
{
int err;
size_t written;
loff_t addr;
uint32_t data = 0;
struct ubi_ec_hdr ec_hdr;
struct ubi_vid_io_buf vidb;
/*
* Note, we cannot generally define VID header buffers on stack,
* because of the way we deal with these buffers (see the header
* comment in this file). But we know this is a NOR-specific piece of
* code, so we can do this. But yes, this is error-prone and we should
* (pre-)allocate VID header buffer instead.
*/
struct ubi_vid_hdr vid_hdr;
/*
* If VID or EC is valid, we have to corrupt them before erasing.
* It is important to first invalidate the EC header, and then the VID
* header. Otherwise a power cut may lead to valid EC header and
* invalid VID header, in which case UBI will treat this PEB as
* corrupted and will try to preserve it, and print scary warnings.
*/
addr = (loff_t)pnum * ubi->peb_size;
err = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
err != UBI_IO_FF){
err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
if(err)
goto error;
}
ubi_init_vid_buf(ubi, &vidb, &vid_hdr);
ubi_assert(&vid_hdr == ubi_get_vid_hdr(&vidb));
err = ubi_io_read_vid_hdr(ubi, pnum, &vidb, 0);
if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
err != UBI_IO_FF){
addr += ubi->vid_hdr_aloffset;
err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
if (err)
goto error;
}
return 0;
error:
/*
* The PEB contains a valid VID or EC header, but we cannot invalidate
* it. Supposedly the flash media or the driver is screwed up, so
* return an error.
*/
ubi_err(ubi, "cannot invalidate PEB %d, write returned %d", pnum, err);
ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
return -EIO;
}
/**
* 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 than 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 = self_check_not_bad(ubi, pnum);
if (err != 0)
return err;
if (ubi->ro_mode) {
ubi_err(ubi, "read-only mode");
return -EROFS;
}
/*
* If the flash is ECC-ed then we have to erase the ECC block before we
* can write to it. But the write is in preparation to an erase in the
* first place. This means we cannot zero out EC and VID before the
* erase and we just have to hope the flash starts erasing from the
* start of the page.
*/
if (ubi->nor_flash && ubi->mtd->writesize == 1) {
err = nor_erase_prepare(ubi, pnum);
if (err)
return err;
}
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(ubi, "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(ubi, "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(ubi, "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(ubi, "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(ubi, "bad VID header offset %d, expected %d",
vid_hdr_offset, ubi->vid_hdr_offset);
goto bad;
}
if (leb_start != ubi->leb_start) {
ubi_err(ubi, "bad data offset %d, expected %d",
leb_start, ubi->leb_start);
goto bad;
}
if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
ubi_err(ubi, "bad erase counter %lld", ec);
goto bad;
}
return 0;
bad:
ubi_err(ubi, "bad EC header");
ubi_dump_ec_hdr(ec_hdr);
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_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;
}
/**
* 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);
ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
ec_hdr->hdr_crc = cpu_to_be32(crc);
err = self_check_ec_hdr(ubi, pnum, ec_hdr);
if (err)
return err;
if (ubi_dbg_power_cut(ubi, POWER_CUT_EC_WRITE))
return -EROFS;
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) {
ubi_err(ubi, "bad copy_flag");
goto bad;
}
if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
data_pad < 0) {
ubi_err(ubi, "negative values");
goto bad;
}
if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
ubi_err(ubi, "bad vol_id");
goto bad;
}
if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
ubi_err(ubi, "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) {
ubi_err(ubi, "bad compat");
goto bad;
}
if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
ubi_err(ubi, "bad vol_type");
goto bad;
}
if (data_pad >= ubi->leb_size / 2) {
ubi_err(ubi, "bad data_pad");
goto bad;
}
if (data_size > ubi->leb_size) {
ubi_err(ubi, "bad data_size");
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) {
ubi_err(ubi, "zero used_ebs");
goto bad;
}
if (data_size == 0) {
ubi_err(ubi, "zero data_size");
goto bad;
}
if (lnum < used_ebs - 1) {
if (data_size != usable_leb_size) {
ubi_err(ubi, "bad data_size");
goto bad;
}
} else if (lnum > used_ebs - 1) {
ubi_err(ubi, "too high lnum");
goto bad;
}
} else {
if (copy_flag == 0) {
if (data_crc != 0) {
ubi_err(ubi, "non-zero data CRC");
goto bad;
}
if (data_size != 0) {
ubi_err(ubi, "non-zero data_size");
goto bad;
}
} else {
if (data_size == 0) {
ubi_err(ubi, "zero data_size of copy");
goto bad;
}
}
if (used_ebs != 0) {
ubi_err(ubi, "bad used_ebs");
goto bad;
}
}
return 0;
bad:
ubi_err(ubi, "bad VID header");
ubi_dump_vid_hdr(vid_hdr);
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
* @vidb: the volume identifier buffer to store data in
* @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 @vidb. 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_io_buf *vidb, int verbose)
{
int err, read_err;
uint32_t crc, magic, hdr_crc;
struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
void *p = vidb->buffer;
dbg_io("read VID header from PEB %d", pnum);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
ubi->vid_hdr_shift + UBI_VID_HDR_SIZE);
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;
}
/**
* ubi_io_write_vid_hdr - write a volume identifier header.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to write to
* @vidb: the volume identifier buffer to write
*
* This function writes the volume identifier header described by @vid_hdr to
* physical eraseblock @pnum. This function automatically fills the
* @vidb->hdr->magic and the @vidb->hdr->version fields, as well as calculates
* header CRC checksum and stores it at vidb->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_io_buf *vidb)
{
struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
int err;
uint32_t crc;
void *p = vidb->buffer;
dbg_io("write VID header to PEB %d", pnum);
ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
err = self_check_peb_ec_hdr(ubi, pnum);
if (err)
return 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 = self_check_vid_hdr(ubi, pnum, vid_hdr);
if (err)
return err;
if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
return -EROFS;
err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
ubi->vid_hdr_alsize);
return err;
}
/**
* self_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, %-EINVAL if
* it is bad and a negative error code if an error occurred.
*/
static int self_check_not_bad(const struct ubi_device *ubi, int pnum)
{
int err;
if (!ubi_dbg_chk_io(ubi))
return 0;
err = ubi_io_is_bad(ubi, pnum);
if (!err)
return err;
ubi_err(ubi, "self-check failed for PEB %d", pnum);
dump_stack();
return err > 0 ? -EINVAL : err;
}
/**
* self_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 %-EINVAL if not.
*/
static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_ec_hdr *ec_hdr)
{
int err;
uint32_t magic;
if (!ubi_dbg_chk_io(ubi))
return 0;
magic = be32_to_cpu(ec_hdr->magic);
if (magic != UBI_EC_HDR_MAGIC) {
ubi_err(ubi, "bad magic %#08x, must be %#08x",
magic, UBI_EC_HDR_MAGIC);
goto fail;
}
err = validate_ec_hdr(ubi, ec_hdr);
if (err) {
ubi_err(ubi, "self-check failed for PEB %d", pnum);
goto fail;
}
return 0;
fail:
ubi_dump_ec_hdr(ec_hdr);
dump_stack();
return -EINVAL;
}
/**
* 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
* 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;
}
/**
* self_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
* %-EINVAL if not.
*/
static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_vid_hdr *vid_hdr)
{
int err;
uint32_t magic;
if (!ubi_dbg_chk_io(ubi))
return 0;
magic = be32_to_cpu(vid_hdr->magic);
if (magic != UBI_VID_HDR_MAGIC) {
ubi_err(ubi, "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(ubi, "self-check failed for PEB %d", pnum);
goto fail;
}
return err;
fail:
ubi_err(ubi, "self-check failed for PEB %d", pnum);
ubi_dump_vid_hdr(vid_hdr);
dump_stack();
return -EINVAL;
}
/**
* 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;
}
/**
* self_check_write - make sure write succeeded.
* @ubi: UBI device description object
* @buf: buffer with data which were written
* @pnum: physical eraseblock number the data were written to
* @offset: offset within the physical eraseblock the data were written to
* @len: how many bytes were written
*
* This functions reads data which were recently written and compares it with
* the original data buffer - the data have to match. Returns zero if the data
* match and a negative error code if not or in case of failure.
*/
static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
int offset, int len)
{
int err, i;
size_t read;
void *buf1;
loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
if (!ubi_dbg_chk_io(ubi))
return 0;
buf1 = __vmalloc(len, GFP_NOFS);
if (!buf1) {
ubi_err(ubi, "cannot allocate memory to check writes");
return 0;
}
err = mtd_read(ubi->mtd, addr, len, &read, buf1);
if (err && !mtd_is_bitflip(err))
goto out_free;
for (i = 0; i < len; i++) {
uint8_t c = ((uint8_t *)buf)[i];
uint8_t c1 = ((uint8_t *)buf1)[i];
int dump_len;
if (c == c1)
continue;
ubi_err(ubi, "self-check failed for PEB %d:%d, len %d",
pnum, offset, len);
ubi_msg(ubi, "data differ at position %d", i);
dump_len = max_t(int, 128, len - i);
ubi_msg(ubi, "hex dump of the original buffer from %d to %d",
i, i + dump_len);
print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
buf + i, dump_len, 1);
ubi_msg(ubi, "hex dump of the read buffer from %d to %d",
i, i + dump_len);
print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
buf1 + i, dump_len, 1);
dump_stack();
err = -EINVAL;
goto out_free;
}
vfree(buf1);
return 0;
out_free:
vfree(buf1);
return err;
}
/**
* ubi_self_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, and a negative error code if not
* or if an error occurred.
*/
int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
{
size_t read;
int err;
void *buf;
loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
if (!ubi_dbg_chk_io(ubi))
return 0;
buf = __vmalloc(len, GFP_NOFS);
if (!buf) {
ubi_err(ubi, "cannot allocate memory to check for 0xFFs");
return 0;
}
err = mtd_read(ubi->mtd, addr, len, &read, buf);
if (err && !mtd_is_bitflip(err)) {
ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
err, len, pnum, offset, read);
goto error;
}
err = ubi_check_pattern(buf, 0xFF, len);
if (err == 0) {
ubi_err(ubi, "flash region at PEB %d:%d, length %d does not contain all 0xFF bytes",
pnum, offset, len);
goto fail;
}
vfree(buf);
return 0;
fail:
ubi_err(ubi, "self-check failed for PEB %d", pnum);
ubi_msg(ubi, "hex dump of the %d-%d region", offset, offset + len);
print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
err = -EINVAL;
error:
dump_stack();
vfree(buf);
return err;
}