mtd: lpddr_cmds: fix signed shifts in lpddr_cmds

There are several places where a value of type 'int' is shifted by
lpddr->chipshift. lpddr->chipshift is derived from QINFO geometry and
might reach 31 when QINFO reports a 2 GiB size - the maximum supported by
LPDDR(1) compliant chips. This may cause unexpected sign-extensions when
casting the integer value to the type of 'unsigned long'.

Use '1UL << lpddr->chipshift' and cast 'j' to unsigned long before
shifting so the computation is performed at the destination width.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: c68264711ca6 ("[MTD] LPDDR Command set driver")
Signed-off-by: Ivan Stepchenko <sid@itb.spb.ru>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

diff --git a/drivers/mtd/lpddr/lpddr_cmds.c b/drivers/mtd/lpddr/lpddr_cmds.c
index 290fd0119e984110b82068017fa5a9b7a6edc71e..cd37d58abacb757426b2b880e99d661b534165ff 100644 (file)
--- a/drivers/mtd/lpddr/lpddr_cmds.c
+++ b/drivers/mtd/lpddr/lpddr_cmds.c
@@ -79,7 +79,7 @@ struct mtd_info *lpddr_cmdset(struct map_info *map)
                mutex_init(&shared[i].lock);
                for (j = 0; j < lpddr->qinfo->HWPartsNum; j++) {
                        *chip = lpddr->chips[i];
-                       chip->start += j << lpddr->chipshift;
+                       chip->start += (unsigned long)j << lpddr->chipshift;
                        chip->oldstate = chip->state = FL_READY;
                        chip->priv = &shared[i];
                        /* those should be reset too since
@@ -559,7 +559,7 @@ static int lpddr_point(struct mtd_info *mtd, loff_t adr, size_t len,
                        break;
 
                if ((len + ofs - 1) >> lpddr->chipshift)
-                       thislen = (1<<lpddr->chipshift) - ofs;
+                       thislen = (1UL << lpddr->chipshift) - ofs;
                else
                        thislen = len;
                /* get the chip */
@@ -575,7 +575,7 @@ static int lpddr_point(struct mtd_info *mtd, loff_t adr, size_t len,
                len -= thislen;
 
                ofs = 0;
-               last_end += 1 << lpddr->chipshift;
+               last_end += 1UL << lpddr->chipshift;
                chipnum++;
                chip = &lpddr->chips[chipnum];
        }
@@ -601,7 +601,7 @@ static int lpddr_unpoint (struct mtd_info *mtd, loff_t adr, size_t len)
                        break;
 
                if ((len + ofs - 1) >> lpddr->chipshift)
-                       thislen = (1<<lpddr->chipshift) - ofs;
+                       thislen = (1UL << lpddr->chipshift) - ofs;
                else
                        thislen = len;