From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162811Ab3LFNvJ (ORCPT ); Fri, 6 Dec 2013 08:51:09 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:44081 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758071Ab3LFNCA (ORCPT ); Fri, 6 Dec 2013 08:02:00 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Pang Xunlei , Zhang Yi , Lu Zhongjun , Brian Norris , Luis Henriques Subject: [PATCH 3.11 110/272] mtd: map: fixed bug in 64-bit systems Date: Fri, 6 Dec 2013 12:56:39 +0000 Message-Id: <1386334761-25517-111-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1386334761-25517-1-git-send-email-luis.henriques@canonical.com> References: <1386334761-25517-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Wang Haitao commit a4d62babf988fe5dfde24437fa135ef147bc7aa0 upstream. Hardware: CPU: XLP832,the 64-bit OS NOR Flash:S29GL128S 128M Software: Kernel:2.6.32.41 Filesystem:JFFS2 When writing files, errors appear: Write len 182 but return retlen 180 Write of 182 bytes at 0x072c815c failed. returned -5, retlen 180 Write len 186 but return retlen 184 Write of 186 bytes at 0x072caff4 failed. returned -5, retlen 184 These errors exist only in 64-bit systems,not in 32-bit systems. After analysis, we found that the left shift operation is wrong in map_word_load_partial. For instance: unsigned char buf[3] ={0x9e,0x3a,0xea}; map_bankwidth(map) is 4; for (i=0; i < 3; i++) { int bitpos; bitpos = (map_bankwidth(map)-1-i)*8; orig.x[0] &= ~(0xff << bitpos); orig.x[0] |= buf[i] << bitpos; } The value of orig.x[0] is expected to be 0x9e3aeaff, but in this situation(64-bit System) we'll get the wrong value of 0xffffffff9e3aeaff due to the 64-bit sign extension: buf[i] is defined as "unsigned char" and the left-shift operation will convert it to the type of "signed int", so when left-shift buf[i] by 24 bits, the final result will get the wrong value: 0xffffffff9e3aeaff. If the left-shift bits are less than 24, then sign extension will not occur. Whereas the bankwidth of the nor flash we used is 4, therefore this BUG emerges. Signed-off-by: Pang Xunlei Signed-off-by: Zhang Yi Signed-off-by: Lu Zhongjun Signed-off-by: Brian Norris Signed-off-by: Luis Henriques --- include/linux/mtd/map.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/mtd/map.h b/include/linux/mtd/map.h index 4b02512..5f487d7 100644 --- a/include/linux/mtd/map.h +++ b/include/linux/mtd/map.h @@ -365,7 +365,7 @@ static inline map_word map_word_load_partial(struct map_info *map, map_word orig bitpos = (map_bankwidth(map)-1-i)*8; #endif orig.x[0] &= ~(0xff << bitpos); - orig.x[0] |= buf[i-start] << bitpos; + orig.x[0] |= (unsigned long)buf[i-start] << bitpos; } } return orig; @@ -384,7 +384,7 @@ static inline map_word map_word_ff(struct map_info *map) if (map_bankwidth(map) < MAP_FF_LIMIT) { int bw = 8 * map_bankwidth(map); - r.x[0] = (1 << bw) - 1; + r.x[0] = (1UL << bw) - 1; } else { for (i=0; i