X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=drivers%2Fmtd%2Fubi%2Fio.c;h=eededf94f5a6c591d003fcd9838e8a06af15f3d4;hp=811775aa8ee80082aa5803a13b3537f2022e5936;hb=16c29dafcc86024048f1dbb8349d31cb22c7c55a;hpb=2d8ad8719591fa803b0d589ed057fa46f49b7155

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 811775aa8ee8..eededf94f5a6 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -91,7 +91,7 @@
 #include <linux/slab.h>
 #include "ubi.h"
 
-#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
+#ifdef CONFIG_MTD_UBI_DEBUG
 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,
@@ -146,6 +146,28 @@ int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 	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 = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
@@ -166,7 +188,7 @@ retry:
 			return UBI_IO_BITFLIPS;
 		}
 
-		if (read != len && retries++ < UBI_IO_RETRIES) {
+		if (retries++ < UBI_IO_RETRIES) {
 			dbg_io("error %d%s while reading %d bytes from PEB %d:%d,"
 			       " read only %zd bytes, retry",
 			       err, errstr, len, pnum, offset, read);
@@ -480,6 +502,13 @@ static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 	size_t written;
 	loff_t addr;
 	uint32_t data = 0;
+	/*
+	 * 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;
 
 	/*
@@ -507,11 +536,13 @@ static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 	 * PEB.
 	 */
 	err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
-	if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR) {
+	if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR ||
+	    err1 == UBI_IO_FF) {
 		struct ubi_ec_hdr ec_hdr;
 
 		err1 = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
-		if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR)
+		if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR ||
+		    err1 == UBI_IO_FF)
 			/*
 			 * Both VID and EC headers are corrupted, so we can
 			 * safely erase this PEB and not afraid that it will be
@@ -752,9 +783,8 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 			if (verbose)
 				ubi_warn("no EC header found at PEB %d, "
 					 "only 0xFF bytes", pnum);
-			else if (UBI_IO_DEBUG)
-				dbg_msg("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
@@ -769,9 +799,9 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 			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);
-		} else if (UBI_IO_DEBUG)
-			dbg_msg("bad magic number at PEB %d: %08x instead of "
-				"%08x", pnum, magic, UBI_EC_HDR_MAGIC);
+		}
+		dbg_bld("bad magic number at PEB %d: %08x instead of "
+			"%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 		return UBI_IO_BAD_HDR;
 	}
 
@@ -783,9 +813,9 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 			ubi_warn("bad EC header CRC at PEB %d, calculated "
 				 "%#08x, read %#08x", pnum, crc, hdr_crc);
 			ubi_dbg_dump_ec_hdr(ec_hdr);
-		} else if (UBI_IO_DEBUG)
-			dbg_msg("bad EC header CRC at PEB %d, calculated "
-				"%#08x, read %#08x", pnum, crc, hdr_crc);
+		}
+		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;
@@ -1008,9 +1038,8 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 			if (verbose)
 				ubi_warn("no VID header found at PEB %d, "
 					 "only 0xFF bytes", pnum);
-			else if (UBI_IO_DEBUG)
-				dbg_msg("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
@@ -1021,9 +1050,9 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 			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);
-		} else if (UBI_IO_DEBUG)
-			dbg_msg("bad magic number at PEB %d: %08x instead of "
-				"%08x", pnum, magic, UBI_VID_HDR_MAGIC);
+		}
+		dbg_bld("bad magic number at PEB %d: %08x instead of "
+			"%08x", pnum, magic, UBI_VID_HDR_MAGIC);
 		return UBI_IO_BAD_HDR;
 	}
 
@@ -1035,9 +1064,9 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 			ubi_warn("bad CRC at PEB %d, calculated %#08x, "
 				 "read %#08x", pnum, crc, hdr_crc);
 			ubi_dbg_dump_vid_hdr(vid_hdr);
-		} else if (UBI_IO_DEBUG)
-			dbg_msg("bad CRC at PEB %d, calculated %#08x, "
-				"read %#08x", pnum, crc, hdr_crc);
+		}
+		dbg_bld("bad CRC at PEB %d, calculated %#08x, "
+			"read %#08x", pnum, crc, hdr_crc);
 		if (!read_err)
 			return UBI_IO_BAD_HDR;
 		else
@@ -1097,7 +1126,7 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 	return err;
 }
 
-#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
+#ifdef CONFIG_MTD_UBI_DEBUG
 
 /**
  * paranoid_check_not_bad - ensure that a physical eraseblock is not bad.
@@ -1111,6 +1140,9 @@ static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum)
 {
 	int err;
 
+	if (!(ubi_chk_flags & UBI_CHK_IO))
+		return 0;
+
 	err = ubi_io_is_bad(ubi, pnum);
 	if (!err)
 		return err;
@@ -1135,6 +1167,9 @@ static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
 	int err;
 	uint32_t magic;
 
+	if (!(ubi_chk_flags & UBI_CHK_IO))
+		return 0;
+
 	magic = be32_to_cpu(ec_hdr->magic);
 	if (magic != UBI_EC_HDR_MAGIC) {
 		ubi_err("bad magic %#08x, must be %#08x",
@@ -1170,6 +1205,9 @@ static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
 	uint32_t crc, hdr_crc;
 	struct ubi_ec_hdr *ec_hdr;
 
+	if (!(ubi_chk_flags & UBI_CHK_IO))
+		return 0;
+
 	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
 	if (!ec_hdr)
 		return -ENOMEM;
@@ -1211,6 +1249,9 @@ static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
 	int err;
 	uint32_t magic;
 
+	if (!(ubi_chk_flags & UBI_CHK_IO))
+		return 0;
+
 	magic = be32_to_cpu(vid_hdr->magic);
 	if (magic != UBI_VID_HDR_MAGIC) {
 		ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
@@ -1249,6 +1290,9 @@ static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
 	struct ubi_vid_hdr *vid_hdr;
 	void *p;
 
+	if (!(ubi_chk_flags & UBI_CHK_IO))
+		return 0;
+
 	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
 	if (!vid_hdr)
 		return -ENOMEM;
@@ -1294,15 +1338,26 @@ int ubi_dbg_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;
 
-	mutex_lock(&ubi->dbg_buf_mutex);
-	err = ubi_io_read(ubi, ubi->dbg_peb_buf, pnum, offset, len);
-	if (err)
-		goto out_unlock;
+	if (!(ubi_chk_flags & UBI_CHK_IO))
+		return 0;
+
+	buf1 = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
+	if (!buf1) {
+		ubi_err("cannot allocate memory to check writes");
+		return 0;
+	}
+
+	err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf1);
+	if (err && err != -EUCLEAN)
+		goto out_free;
 
 	for (i = 0; i < len; i++) {
 		uint8_t c = ((uint8_t *)buf)[i];
-		uint8_t c1 = ((uint8_t *)ubi->dbg_peb_buf)[i];
+		uint8_t c1 = ((uint8_t *)buf1)[i];
 		int dump_len;
 
 		if (c == c1)
@@ -1319,17 +1374,17 @@ int ubi_dbg_check_write(struct ubi_device *ubi, const void *buf, int pnum,
 		ubi_msg("hex dump of the read buffer from %d to %d",
 			i, i + dump_len);
 		print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
-			       ubi->dbg_peb_buf + i, dump_len, 1);
+			       buf1 + i, dump_len, 1);
 		ubi_dbg_dump_stack();
 		err = -EINVAL;
-		goto out_unlock;
+		goto out_free;
 	}
-	mutex_unlock(&ubi->dbg_buf_mutex);
 
+	vfree(buf1);
 	return 0;
 
-out_unlock:
-	mutex_unlock(&ubi->dbg_buf_mutex);
+out_free:
+	vfree(buf1);
 	return err;
 }
 
@@ -1348,36 +1403,44 @@ int ubi_dbg_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;
 
-	mutex_lock(&ubi->dbg_buf_mutex);
-	err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf);
+	if (!(ubi_chk_flags & UBI_CHK_IO))
+		return 0;
+
+	buf = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
+	if (!buf) {
+		ubi_err("cannot allocate memory to check for 0xFFs");
+		return 0;
+	}
+
+	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 = ubi_check_pattern(ubi->dbg_peb_buf, 0xFF, len);
+	err = ubi_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;
 	}
-	mutex_unlock(&ubi->dbg_buf_mutex);
 
+	vfree(buf);
 	return 0;
 
 fail:
 	ubi_err("paranoid check failed for PEB %d", pnum);
 	ubi_msg("hex dump of the %d-%d region", offset, offset + len);
-	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
-		       ubi->dbg_peb_buf, len, 1);
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
 	err = -EINVAL;
 error:
 	ubi_dbg_dump_stack();
-	mutex_unlock(&ubi->dbg_buf_mutex);
+	vfree(buf);
 	return err;
 }
 
-#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */
+#endif /* CONFIG_MTD_UBI_DEBUG */