diff options
Diffstat (limited to 'drivers/mtd/ubi/io.c')
| -rw-r--r-- | drivers/mtd/ubi/io.c | 1259 |
1 files changed, 1259 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c new file mode 100644 index 000000000000..438914d05151 --- /dev/null +++ b/drivers/mtd/ubi/io.c @@ -0,0 +1,1259 @@ +/* + * 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(const 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 data integrity + * problems, for example it can me 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(const 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(const 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 = 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(const struct ubi_device *ubi, int pnum) +{ + void *buf; + int err, i, patt_count; + + buf = kmalloc(ubi->peb_size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + patt_count = ARRAY_SIZE(patterns); + ubi_assert(patt_count > 0); + + 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, buf, pnum, 0, ubi->peb_size); + if (err) + goto out; + + err = check_pattern(buf, 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(buf, patterns[i], ubi->peb_size); + err = ubi_io_write(ubi, buf, pnum, 0, ubi->peb_size); + if (err) + goto out; + + memset(buf, ~patterns[i], ubi->peb_size); + err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size); + if (err) + goto out; + + err = check_pattern(buf, 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: + 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. + */ + err = -EIO; + kfree(buf); + 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(const 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 = ubi64_to_cpu(ec_hdr->ec); + vid_hdr_offset = ubi32_to_cpu(ec_hdr->vid_hdr_offset); + leb_start = ubi32_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(const 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 = ubi32_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 = ubi32_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(const 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_ubi32(UBI_EC_HDR_MAGIC); + ec_hdr->version = UBI_VERSION; + ec_hdr->vid_hdr_offset = cpu_to_ubi32(ubi->vid_hdr_offset); + ec_hdr->data_offset = cpu_to_ubi32(ubi->leb_start); + crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC); + ec_hdr->hdr_crc = cpu_to_ubi32(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 = ubi32_to_cpu(vid_hdr->vol_id); + int lnum = ubi32_to_cpu(vid_hdr->lnum); + int compat = vid_hdr->compat; + int data_size = ubi32_to_cpu(vid_hdr->data_size); + int used_ebs = ubi32_to_cpu(vid_hdr->used_ebs); + int data_pad = ubi32_to_cpu(vid_hdr->data_pad); + int data_crc = ubi32_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(const 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 = ubi32_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 = ubi32_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(const 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_ubi32(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_ubi32(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 = ubi32_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_KERNEL); + 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 = ubi32_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 = ubi32_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); + 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 = ubi32_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(const 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; + + buf = kzalloc(len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + err = ubi->mtd->read(ubi->mtd, addr, len, &read, 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(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; + } + + kfree(buf); + return 0; + +fail: + ubi_err("paranoid check failed for PEB %d", pnum); + dbg_msg("hex dump of the %d-%d region", offset, offset + len); + ubi_dbg_hexdump(buf, len); + err = 1; +error: + ubi_dbg_dump_stack(); + kfree(buf); + return err; +} + +#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */ |