From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pan Xinhui Date: Tue, 26 Apr 2016 10:07:37 +0000 Subject: Re: [PATCH V2]sh: cmpxchg: fix a bit shift bug in big_endian os Message-Id: <571F3DE9.6010500@linux.vnet.ibm.com> List-Id: References: <5715D72D.7060501@linux.vnet.ibm.com> <5717247C.7080002@linux.vnet.ibm.com> <20160426013913.GJ21636@brightrain.aerifal.cx> In-Reply-To: <20160426013913.GJ21636@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Rich Felker Cc: linux-kernel@vger.kernel.org, ysato@users.sourceforge.jp, mst@redhat.com, peterz@infradead.org, linux-sh@vger.kernel.org On 2016年04月26日 09:39, Rich Felker wrote: > On Wed, Apr 20, 2016 at 02:41:00PM +0800, Pan Xinhui wrote: >> From: Pan Xinhui >> >> Correct bitoff in big endian OS. >> Current code works correctly for 1 byte but not for 2 bytes. >> >> Fixes: 3226aad81aa6 ("sh: support 1 and 2 byte xchg") >> Signed-off-by: Pan Xinhui >> Acked-by: Michael S. Tsirkin >> --- >> changes from V1: >> just add some patch comments. no code changes. > > Looks good. Are you aware of any code affected by this bug that would > make it a regression in 4.6? If so I'll try to get this in now as a > bugfix; otherwise I'll include it in stuff for 4.7. > no idea about what code is affected. 4.7 is okay I think. :) xinhui > Rich > > >> --- >> arch/sh/include/asm/cmpxchg-xchg.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/sh/include/asm/cmpxchg-xchg.h b/arch/sh/include/asm/cmpxchg-xchg.h >> index 7219719..1e881f5 100644 >> --- a/arch/sh/include/asm/cmpxchg-xchg.h >> +++ b/arch/sh/include/asm/cmpxchg-xchg.h >> @@ -21,7 +21,7 @@ static inline u32 __xchg_cmpxchg(volatile void *ptr, u32 x, int size) >> int off = (unsigned long)ptr % sizeof(u32); >> volatile u32 *p = ptr - off; >> #ifdef __BIG_ENDIAN >> - int bitoff = (sizeof(u32) - 1 - off) * BITS_PER_BYTE; >> + int bitoff = (sizeof(u32) - size - off) * BITS_PER_BYTE; >> #else >> int bitoff = off * BITS_PER_BYTE; >> #endif >> -- >> 1.9.1 > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751982AbcDZKI6 (ORCPT ); Tue, 26 Apr 2016 06:08:58 -0400 Received: from e23smtp05.au.ibm.com ([202.81.31.147]:33918 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751890AbcDZKI4 (ORCPT ); Tue, 26 Apr 2016 06:08:56 -0400 X-IBM-Helo: d23dlp02.au.ibm.com X-IBM-MailFrom: xinhui@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-sh@vger.kernel.org Message-ID: <571F3DE9.6010500@linux.vnet.ibm.com> Date: Tue, 26 Apr 2016 18:07:37 +0800 From: Pan Xinhui User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: Rich Felker CC: linux-kernel@vger.kernel.org, ysato@users.sourceforge.jp, mst@redhat.com, peterz@infradead.org, linux-sh@vger.kernel.org Subject: Re: [PATCH V2]sh: cmpxchg: fix a bit shift bug in big_endian os References: <5715D72D.7060501@linux.vnet.ibm.com> <5717247C.7080002@linux.vnet.ibm.com> <20160426013913.GJ21636@brightrain.aerifal.cx> In-Reply-To: <20160426013913.GJ21636@brightrain.aerifal.cx> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16042610-0017-0000-0000-000004534523 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016年04月26日 09:39, Rich Felker wrote: > On Wed, Apr 20, 2016 at 02:41:00PM +0800, Pan Xinhui wrote: >> From: Pan Xinhui >> >> Correct bitoff in big endian OS. >> Current code works correctly for 1 byte but not for 2 bytes. >> >> Fixes: 3226aad81aa6 ("sh: support 1 and 2 byte xchg") >> Signed-off-by: Pan Xinhui >> Acked-by: Michael S. Tsirkin >> --- >> changes from V1: >> just add some patch comments. no code changes. > > Looks good. Are you aware of any code affected by this bug that would > make it a regression in 4.6? If so I'll try to get this in now as a > bugfix; otherwise I'll include it in stuff for 4.7. > no idea about what code is affected. 4.7 is okay I think. :) xinhui > Rich > > >> --- >> arch/sh/include/asm/cmpxchg-xchg.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/sh/include/asm/cmpxchg-xchg.h b/arch/sh/include/asm/cmpxchg-xchg.h >> index 7219719..1e881f5 100644 >> --- a/arch/sh/include/asm/cmpxchg-xchg.h >> +++ b/arch/sh/include/asm/cmpxchg-xchg.h >> @@ -21,7 +21,7 @@ static inline u32 __xchg_cmpxchg(volatile void *ptr, u32 x, int size) >> int off = (unsigned long)ptr % sizeof(u32); >> volatile u32 *p = ptr - off; >> #ifdef __BIG_ENDIAN >> - int bitoff = (sizeof(u32) - 1 - off) * BITS_PER_BYTE; >> + int bitoff = (sizeof(u32) - size - off) * BITS_PER_BYTE; >> #else >> int bitoff = off * BITS_PER_BYTE; >> #endif >> -- >> 1.9.1 >