From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752704AbdJSMlT (ORCPT ); Thu, 19 Oct 2017 08:41:19 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:60456 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751411AbdJSMlS (ORCPT ); Thu, 19 Oct 2017 08:41:18 -0400 Date: Thu, 19 Oct 2017 13:40:34 +0100 From: Russell King - ARM Linux To: "Liuwenliang (Lamb)" Cc: kbuild test robot , "kbuild-all@01.org" , "aryabinin@virtuozzo.com" , "afzal.mohd.ma@gmail.com" , "f.fainelli@gmail.com" , "labbott@redhat.com" , "kirill.shutemov@linux.intel.com" , "mhocko@suse.com" , "cdall@linaro.org" , "marc.zyngier@arm.com" , "catalin.marinas@arm.com" , "akpm@linux-foundation.org" , "mawilcox@microsoft.com" , "tglx@linutronix.de" , "thgarnie@google.com" , "keescook@chromium.org" , "arnd@arndb.de" , "vladimir.murzin@arm.com" , "tixy@linaro.org" , "ard.biesheuvel@linaro.org" , "robin.murphy@arm.com" , "mingo@kernel.org" , "grygorii.strashko@linaro.org" , "glider@google.com" , "dvyukov@google.com" , "opendmb@gmail.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "kasan-dev@googlegroups.com" , "linux-mm@kvack.org" , Jiazhenghua , Dailei , Zengweilin , Heshaoliang Subject: Re: [PATCH 04/11] Define the virtual space of KASan's shadow region Message-ID: <20171019124034.GW20805@n2100.armlinux.org.uk> References: <20171011082227.20546-5-liuwenliang@huawei.com> <201710141957.mbxeZJHB%fengguang.wu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 16, 2017 at 11:42:05AM +0000, Liuwenliang (Lamb) wrote: > On 10/16/2017 07:03 PM, Abbott Liu wrote: > >arch/arm/kernel/entry-armv.S:348: Error: selected processor does not support `movw r1, > #:lower16:((((0xC0000000-0x01000000)>>3)+((0xC0000000-0x01000000)-(1<<29))))' in ARM mode > >arch/arm/kernel/entry-armv.S:348: Error: selected processor does not support `movt r1, > #:upper16:((((0xC0000000-0x01000000)>>3)+((0xC0000000-0x01000000)-(1<<29))))' in ARM mode > > Thanks for building test. This error can be solved by following code: > --- a/arch/arm/kernel/entry-armv.S > +++ b/arch/arm/kernel/entry-armv.S > @@ -188,8 +188,7 @@ ENDPROC(__und_invalid) > get_thread_info tsk > ldr r0, [tsk, #TI_ADDR_LIMIT] > #ifdef CONFIG_KASAN > - movw r1, #:lower16:TASK_SIZE > - movt r1, #:upper16:TASK_SIZE > + ldr r1, =TASK_SIZE > #else > mov r1, #TASK_SIZE > #endif We can surely do better than this with macros and condition support - we can build-time test in the assembler whether TASK_SIZE can fit in a normal "mov", whether we can use the movw/movt instructions, or fall back to ldr if necessary. I'd rather we avoided "ldr" here where possible. > @@ -446,7 +445,12 @@ ENDPROC(__fiq_abt) > @ if it was interrupted in a critical region. Here we > @ perform a quick test inline since it should be false > @ 99.9999% of the time. The rest is done out of line. > +#if CONFIG_KASAN > + ldr r0, =TASK_SIZE > + cmp r4, r0 > +#else > cmp r4, #TASK_SIZE Same sort of thing goes for here - we can select the instruction at runtime using the assembler's macros and condition support. We know that TASK_SIZE is going to be one of a limited set of values. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up