From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f177.google.com (mail-ob0-f177.google.com [209.85.214.177]) by kanga.kvack.org (Postfix) with ESMTP id 7F1C26B0038 for ; Fri, 9 Jan 2015 07:41:34 -0500 (EST) Received: by mail-ob0-f177.google.com with SMTP id va2so12506462obc.8 for ; Fri, 09 Jan 2015 04:41:34 -0800 (PST) Received: from cnbjrel02.sonyericsson.com (cnbjrel02.sonyericsson.com. [219.141.167.166]) by mx.google.com with ESMTPS id oz5si5348004oeb.95.2015.01.09.04.41.30 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 09 Jan 2015 04:41:32 -0800 (PST) From: "Wang, Yalin" Date: Fri, 9 Jan 2015 20:40:56 +0800 Subject: RE: [RFC V6 2/3] arm:add bitrev.h file to support rbit instruction Message-ID: <35FD53F367049845BC99AC72306C23D103EDAF89E198@CNBJMBX05.corpusers.net> References: <20141030135749.GE32589@arm.com> <35FD53F367049845BC99AC72306C23D103E010D18272@CNBJMBX05.corpusers.net> <35FD53F367049845BC99AC72306C23D103E010D18273@CNBJMBX05.corpusers.net> <35FD53F367049845BC99AC72306C23D103E010D18275@CNBJMBX05.corpusers.net> <20141113235322.GC4042@n2100.arm.linux.org.uk> <35FD53F367049845BC99AC72306C23D103E010D1829B@CNBJMBX05.corpusers.net> <20141114095812.GG4042@n2100.arm.linux.org.uk> <35FD53F367049845BC99AC72306C23D103E688B313C6@CNBJMBX05.corpusers.net> <20150108184059.GZ12302@n2100.arm.linux.org.uk> <35FD53F367049845BC99AC72306C23D103EDAF89E195@CNBJMBX05.corpusers.net> <20150109111048.GE12302@n2100.arm.linux.org.uk> In-Reply-To: <20150109111048.GE12302@n2100.arm.linux.org.uk> Content-Language: en-US Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: 'Russell King - ARM Linux' Cc: 'Ard Biesheuvel' , 'Will Deacon' , "'linux-kernel@vger.kernel.org'" , "'akinobu.mita@gmail.com'" , "'linux-mm@kvack.org'" , 'Joe Perches' , "'linux-arm-kernel@lists.infradead.org'" > -----Original Message----- > From: Russell King - ARM Linux [mailto:linux@arm.linux.org.uk] > Sent: Friday, January 09, 2015 7:11 PM > To: Wang, Yalin > Cc: 'Ard Biesheuvel'; 'Will Deacon'; 'linux-kernel@vger.kernel.org'; > 'akinobu.mita@gmail.com'; 'linux-mm@kvack.org'; 'Joe Perches'; 'linux-arm= - > kernel@lists.infradead.org' > Subject: Re: [RFC V6 2/3] arm:add bitrev.h file to support rbit instructi= on >=20 > On Fri, Jan 09, 2015 at 10:16:32AM +0800, Wang, Yalin wrote: > > > -----Original Message----- > > > From: Russell King - ARM Linux [mailto:linux@arm.linux.org.uk] > > > Sent: Friday, January 09, 2015 2:41 AM > > > To: Wang, Yalin > > > Cc: 'Will Deacon'; 'Ard Biesheuvel'; 'linux-kernel@vger.kernel.org'; > > > 'akinobu.mita@gmail.com'; 'linux-mm@kvack.org'; 'Joe Perches'; > > > 'linux-arm- kernel@lists.infradead.org' > > > Subject: Re: [RFC V6 2/3] arm:add bitrev.h file to support rbit > > > instruction > > > > > > The root cause is that the kernel being built is supposed to support > > > both > > > ARMv7 and ARMv6K CPUs. However, "rbit" is only available on > > > ARMv6T2 (thumb2) and ARMv7, and not plain ARMv6 or ARMv6K CPUs. > > > > > In the patch that you applied: > > 8205/1 add bitrev.h file to support rbit instruction > > > > I have add : > > + select HAVE_ARCH_BITREVERSE if ((CPU_V7M || CPU_V7) && !CPU_V6) > > > > If you build kernel support ARMv6K, should CONFIG_CPU_V6=3Dy, isn't it = ? > > Then will not build hardware rbit instruction, isn't it ? >=20 > The config has: >=20 > CONFIG_CPU_PJ4=3Dy > # CONFIG_CPU_V6 is not set > CONFIG_CPU_V6K=3Dy > CONFIG_CPU_V7=3Dy > CONFIG_CPU_32v6=3Dy > CONFIG_CPU_32v6K=3Dy > CONFIG_CPU_32v7=3Dy >=20 > And no, the CONFIG_CPU_V* flags refer to the CPUs. The > CONFIG_CPU_32v* symbols refer to the CPU architectures. >=20 Oh, I see, How about change like this: + select HAVE_ARCH_BITREVERSE if ((CPU_V7M || CPU_V7) && !CPU_V6 && !CPU_V6= K) I am not sure if I also need add some older CPU types like !CPU_ARM9TDMI &&= =1B$B!!=1B(B!CPU_ARM940T ? Another solution is: + select HAVE_ARCH_BITREVERSE if ((CPU_32V7M || CPU_32V7) && !CPU_32V6 && != CPU_32V5 && !CPU_32V4 && !CPU_32V4T && !CPU_32V3) By the way, I am not clear about the difference between CPU_V6 and CPU_V6K,= could you tell me? :) Thank you=20 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org