From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH 11/14] ARM: v6k: use CPU domain feature if we include support for arch < ARMv6K Date: Fri, 28 Jan 2011 13:10:56 +0000 Message-ID: <1296220256.1799.62.camel@e102109-lin.cambridge.arm.com> References: <20110117192050.GE23331@n2100.arm.linux.org.uk> <20110127185935.GA1651@n2100.arm.linux.org.uk> <1296207966.1799.10.camel@e102109-lin.cambridge.arm.com> <20110128095953.GA13005@n2100.arm.linux.org.uk> <1296211611.1799.15.camel@e102109-lin.cambridge.arm.com> <20110128110629.GB13005@n2100.arm.linux.org.uk> <1296217518.1799.59.camel@e102109-lin.cambridge.arm.com> <20110128130532.GC13005@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Return-path: Received: from service87.mimecast.com ([94.185.240.25]:55711 "HELO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750982Ab1A1NLK convert rfc822-to-8bit (ORCPT ); Fri, 28 Jan 2011 08:11:10 -0500 In-Reply-To: <20110128130532.GC13005@n2100.arm.linux.org.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Russell King - ARM Linux Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org On Fri, 2011-01-28 at 13:05 +0000, Russell King - ARM Linux wrote: > On Fri, Jan 28, 2011 at 12:25:18PM +0000, Catalin Marinas wrote: > > With your latest patches, do we use the TLS emulation on ARMv7 (UP) if > > v6 is compiled in? If that's the case, we may have a problem - I talked > > to the toolchain guys and it looks like code optimised for ARMv7 reads > > the TLS register directly without going through the kuser helper. > > That's not a problem, because you wouldn't run ARMv7 optimized userspace > on an ARMv6 CPU. That's not what this whole exercise is about. But you can run ARMv7 optimised userspace on ARMv7 CPU with a kernel image compiled for v6+v7. -- Catalin From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Fri, 28 Jan 2011 13:10:56 +0000 Subject: [PATCH 11/14] ARM: v6k: use CPU domain feature if we include support for arch < ARMv6K In-Reply-To: <20110128130532.GC13005@n2100.arm.linux.org.uk> References: <20110117192050.GE23331@n2100.arm.linux.org.uk> <20110127185935.GA1651@n2100.arm.linux.org.uk> <1296207966.1799.10.camel@e102109-lin.cambridge.arm.com> <20110128095953.GA13005@n2100.arm.linux.org.uk> <1296211611.1799.15.camel@e102109-lin.cambridge.arm.com> <20110128110629.GB13005@n2100.arm.linux.org.uk> <1296217518.1799.59.camel@e102109-lin.cambridge.arm.com> <20110128130532.GC13005@n2100.arm.linux.org.uk> Message-ID: <1296220256.1799.62.camel@e102109-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, 2011-01-28 at 13:05 +0000, Russell King - ARM Linux wrote: > On Fri, Jan 28, 2011 at 12:25:18PM +0000, Catalin Marinas wrote: > > With your latest patches, do we use the TLS emulation on ARMv7 (UP) if > > v6 is compiled in? If that's the case, we may have a problem - I talked > > to the toolchain guys and it looks like code optimised for ARMv7 reads > > the TLS register directly without going through the kuser helper. > > That's not a problem, because you wouldn't run ARMv7 optimized userspace > on an ARMv6 CPU. That's not what this whole exercise is about. But you can run ARMv7 optimised userspace on ARMv7 CPU with a kernel image compiled for v6+v7. -- Catalin