[ARM] 4837/1: make __get_unaligned_*() return unsigned types
authorLennert Buytenhek <buytenh@wantstofly.org>
Fri, 22 Feb 2008 23:23:48 +0000 (00:23 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Fri, 29 Feb 2008 22:46:48 +0000 (22:46 +0000)
commit94a3f78566ef98a48814d82892f28bb741624cb8
treecb8e4904737c84c64129753e4148b9845b49afa1
parentb98d7291883f7ed27e3f4b59bc12dc963c9f72a6
[ARM] 4837/1: make __get_unaligned_*() return unsigned types

Eric Sandeen tracked an XFS on ARM corruption bug down to a function
under fs/xfs/ involving some get_unaligned() calls on u64 pointers.
As it turns out, calling ARM's get_unaligned() on a u64 pointer
pointing to the following byte sequence:

80 81 82 83 84 85 86 87

would return ffffffff83828180 (LE mode.)  This turns out to be
because of implicit u8 -> int promotion in ARM's implementation of
various helpers for get_unaligned(), causing them to accidentally
return signed instead of unsigned values, which in turn caused the
subsequent casts to unsigned long long in __get_unaligned_8_[bl]e()
to sign-extend the lower words.

Fix by casting the return values of __get_unaligned_[24]_[bl]e()
to unsigned int.

Cc: Eric Sandeen <sandeen@sandeen.net>
Cc: Rabeeh Khoury <rabeeh@marvell.com>
Cc: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
include/asm-arm/unaligned.h