From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f172.google.com (mail-wi0-f172.google.com [209.85.212.172]) by kanga.kvack.org (Postfix) with ESMTP id 99FEF6B0038 for ; Fri, 9 Jan 2015 06:11:05 -0500 (EST) Received: by mail-wi0-f172.google.com with SMTP id n3so1532023wiv.5 for ; Fri, 09 Jan 2015 03:11:05 -0800 (PST) Received: from pandora.arm.linux.org.uk (pandora.arm.linux.org.uk. [2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by mx.google.com with ESMTPS id dg2si3278085wib.98.2015.01.09.03.11.04 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Fri, 09 Jan 2015 03:11:04 -0800 (PST) Date: Fri, 9 Jan 2015 11:10:48 +0000 From: Russell King - ARM Linux Subject: Re: [RFC V6 2/3] arm:add bitrev.h file to support rbit instruction Message-ID: <20150109111048.GE12302@n2100.arm.linux.org.uk> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <35FD53F367049845BC99AC72306C23D103EDAF89E195@CNBJMBX05.corpusers.net> Sender: owner-linux-mm@kvack.org List-ID: 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'" 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=y, isn't it ? > Then will not build hardware rbit instruction, isn't it ? The config has: CONFIG_CPU_PJ4=y # CONFIG_CPU_V6 is not set CONFIG_CPU_V6K=y CONFIG_CPU_V7=y CONFIG_CPU_32v6=y CONFIG_CPU_32v6K=y CONFIG_CPU_32v7=y And no, the CONFIG_CPU_V* flags refer to the CPUs. The CONFIG_CPU_32v* symbols refer to the CPU architectures. -- FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up according to speedtest.net. -- 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