From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 19 Aug 2011 03:56:31 +0200 (CEST) Received: from mail.windriver.com ([147.11.1.11]:46586 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1492167Ab1HSB4W (ORCPT ); Fri, 19 Aug 2011 03:56:22 +0200 Received: from ALA-HCA.corp.ad.wrs.com (ala-hca [147.11.189.40]) by mail.windriver.com (8.14.3/8.14.3) with ESMTP id p7J1uBok013586 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Thu, 18 Aug 2011 18:56:11 -0700 (PDT) Received: from localhost (128.224.158.133) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server (TLS) id 14.1.255.0; Thu, 18 Aug 2011 18:56:11 -0700 Date: Fri, 19 Aug 2011 09:56:07 +0800 From: Yong Zhang To: David Daney CC: , , Ralf Baechle Subject: Re: [PATCH] MIPS: use 32-bit wrapper for compat_sys_futex Message-ID: <20110819015607.GA2798@windriver.com> Reply-To: Yong Zhang References: <1313546094-11882-1-git-send-email-yong.zhang@windriver.com> <4E4BF7C0.80703@cavium.com> <20110818023247.GA3750@windriver.com> <4E4D3C8D.1040707@cavium.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <4E4D3C8D.1040707@cavium.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Originating-IP: [128.224.158.133] X-archive-position: 30912 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: yong.zhang@windriver.com Precedence: bulk X-list: linux-mips Return-Path: X-Keywords: X-UID: 13794 On Thu, Aug 18, 2011 at 09:23:41AM -0700, David Daney wrote: > On 08/17/2011 07:32 PM, Yong Zhang wrote: > >On Wed, Aug 17, 2011 at 10:17:52AM -0700, David Daney wrote: > >>>diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S > >>>index 46c4763..f48b18e 100644 > >>>--- a/arch/mips/kernel/scall64-o32.S > >>>+++ b/arch/mips/kernel/scall64-o32.S > >>>@@ -441,7 +441,7 @@ sys_call_table: > >>> PTR sys_fremovexattr /* 4235 */ > >>> PTR sys_tkill > >>> PTR sys_sendfile64 > >>>- PTR compat_sys_futex > >>>+ PTR sys_32_futex > >> > >>This change is redundant, scall64-o32.S already does the right thing > > > >My first virsion(not sent out) doesn't include scall64-o32.S either. > > > >>so additional zero extending is not needed and is just extra > >>instructions to execute for no reason. > > > >Why I'm adding it here is for: > >1)code consistent, otherwise we must move SYSCALL_DEFINE6(32_futex,...) > > under CONFIG_MIPS32_N32; > > No, you don't have to move it. Just don't call it. > > > >2)I'm afraid there may be some other way to touch the high 32-bit of a > > register, so touching scall64-o32.S is also for safety(due to unknown > > reason, fix me if I'm wrong). > > OK: You are mistaken. You claim you don't understand what the code > does. That is really a poor justification for modifying it. If you don't like it and you are sure there is no potential security problem, just make a patch to remove it. Go ahead. Thanks, Yong From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.windriver.com ([147.11.1.11]:46586 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1492167Ab1HSB4W (ORCPT ); Fri, 19 Aug 2011 03:56:22 +0200 Date: Fri, 19 Aug 2011 09:56:07 +0800 From: Yong Zhang Subject: Re: [PATCH] MIPS: use 32-bit wrapper for compat_sys_futex Message-ID: <20110819015607.GA2798@windriver.com> Reply-To: Yong Zhang References: <1313546094-11882-1-git-send-email-yong.zhang@windriver.com> <4E4BF7C0.80703@cavium.com> <20110818023247.GA3750@windriver.com> <4E4D3C8D.1040707@cavium.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <4E4D3C8D.1040707@cavium.com> Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org Return-Path: To: David Daney Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Ralf Baechle Message-ID: <20110819015607.NibTng9xAJvnaoCj-R_KoDj9yjIaDCaFzwnje9fT1mo@z> On Thu, Aug 18, 2011 at 09:23:41AM -0700, David Daney wrote: > On 08/17/2011 07:32 PM, Yong Zhang wrote: > >On Wed, Aug 17, 2011 at 10:17:52AM -0700, David Daney wrote: > >>>diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S > >>>index 46c4763..f48b18e 100644 > >>>--- a/arch/mips/kernel/scall64-o32.S > >>>+++ b/arch/mips/kernel/scall64-o32.S > >>>@@ -441,7 +441,7 @@ sys_call_table: > >>> PTR sys_fremovexattr /* 4235 */ > >>> PTR sys_tkill > >>> PTR sys_sendfile64 > >>>- PTR compat_sys_futex > >>>+ PTR sys_32_futex > >> > >>This change is redundant, scall64-o32.S already does the right thing > > > >My first virsion(not sent out) doesn't include scall64-o32.S either. > > > >>so additional zero extending is not needed and is just extra > >>instructions to execute for no reason. > > > >Why I'm adding it here is for: > >1)code consistent, otherwise we must move SYSCALL_DEFINE6(32_futex,...) > > under CONFIG_MIPS32_N32; > > No, you don't have to move it. Just don't call it. > > > >2)I'm afraid there may be some other way to touch the high 32-bit of a > > register, so touching scall64-o32.S is also for safety(due to unknown > > reason, fix me if I'm wrong). > > OK: You are mistaken. You claim you don't understand what the code > does. That is really a poor justification for modifying it. If you don't like it and you are sure there is no potential security problem, just make a patch to remove it. Go ahead. Thanks, Yong