From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH 00/14] Fix issues with ARMv6+v6k+v7 kernels Date: Wed, 9 Feb 2011 09:48:53 -0800 Message-ID: <20110209174853.GV20795@atomide.com> References: <20110208164747.GD6188@n2100.arm.linux.org.uk> <78d0134576ace6be5874871076cf0c10@mail.gmail.com> <20110209003537.GQ20795@atomide.com> <54f225541194205f01fe9f03b5110d16@mail.gmail.com> <80a27c86473cf29a9fa5e68aa29eef46@mail.gmail.com> <20110209162421.GU20795@atomide.com> <20110209163204.GB11460@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:61447 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754686Ab1BIRt2 (ORCPT ); Wed, 9 Feb 2011 12:49:28 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Nicolas Pitre Cc: Russell King - ARM Linux , Santosh Shilimkar , Dave Martin , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org * Nicolas Pitre [110209 08:44]: > On Wed, 9 Feb 2011, Russell King - ARM Linux wrote: > > > On Wed, Feb 09, 2011 at 08:24:21AM -0800, Tony Lindgren wrote: > > > * Santosh Shilimkar [110209 01:59]: > > > > > From: Dave Martin [mailto:dave.martin@linaro.org] > > > > > > > > > > You could also have a "v7+" unified kernel -- i.e., supporting > > > > > OMAP3+4+SMP. > > > > > This is what we currently do in Linaro, since we're focusing on v7 > > > > > and above. > > > > > > > > > This sounds good way forward considering future OMAP architectures > > > > as well. > > > > > > > > But I let Tony comment on this idea. > > > > > > AFAIK these issues will be hopefully sorted out by the time the > > > next merge window opens. For the -rc cycle, disabling SMP in > > > config if ARMv6 is selected should do the trick. > > > > That's not soo easy - as we don't know in the Kconfig whether we include > > ARMv6 rather than ARMv6K. It's exactly the same problem I ran into which > > inflated the v6v7 patchset. > > > > Maybe the best thing to do is: > > > > config CPU_32v6K > > bool "Support ARM V6K processor extensions" if !SMP > > depends on CPU_V6 || CPU_V7 > > default y if SMP && !(ARCH_MX3 || ARCH_OMAP2) > > > > drop the ' && !(ARCH_MX3 || ARCH_OMAP2)' and just let people run into the > > resulting undefined instruction traps if they try to run the kernel on > > V6 non-K hardware. Not ideal, but I don't see any other 'simple' solution > > to this. > > This should be good enough. We're looking for a temporary stopgate > solution to prevent people from corrupting their data, and the real fix > will be available in the next kernel. OK. This patch will be needed anyways for the real fixes. And no temporary apply-undo type patching needed. The only drawback is that omap2420 and 2430 won't boot with omap2plus_defconfig, but that will be only for a few weeks. Acked-by: Tony Lindgren From mboxrd@z Thu Jan 1 00:00:00 1970 From: tony@atomide.com (Tony Lindgren) Date: Wed, 9 Feb 2011 09:48:53 -0800 Subject: [PATCH 00/14] Fix issues with ARMv6+v6k+v7 kernels In-Reply-To: References: <20110208164747.GD6188@n2100.arm.linux.org.uk> <78d0134576ace6be5874871076cf0c10@mail.gmail.com> <20110209003537.GQ20795@atomide.com> <54f225541194205f01fe9f03b5110d16@mail.gmail.com> <80a27c86473cf29a9fa5e68aa29eef46@mail.gmail.com> <20110209162421.GU20795@atomide.com> <20110209163204.GB11460@n2100.arm.linux.org.uk> Message-ID: <20110209174853.GV20795@atomide.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org * Nicolas Pitre [110209 08:44]: > On Wed, 9 Feb 2011, Russell King - ARM Linux wrote: > > > On Wed, Feb 09, 2011 at 08:24:21AM -0800, Tony Lindgren wrote: > > > * Santosh Shilimkar [110209 01:59]: > > > > > From: Dave Martin [mailto:dave.martin at linaro.org] > > > > > > > > > > You could also have a "v7+" unified kernel -- i.e., supporting > > > > > OMAP3+4+SMP. > > > > > This is what we currently do in Linaro, since we're focusing on v7 > > > > > and above. > > > > > > > > > This sounds good way forward considering future OMAP architectures > > > > as well. > > > > > > > > But I let Tony comment on this idea. > > > > > > AFAIK these issues will be hopefully sorted out by the time the > > > next merge window opens. For the -rc cycle, disabling SMP in > > > config if ARMv6 is selected should do the trick. > > > > That's not soo easy - as we don't know in the Kconfig whether we include > > ARMv6 rather than ARMv6K. It's exactly the same problem I ran into which > > inflated the v6v7 patchset. > > > > Maybe the best thing to do is: > > > > config CPU_32v6K > > bool "Support ARM V6K processor extensions" if !SMP > > depends on CPU_V6 || CPU_V7 > > default y if SMP && !(ARCH_MX3 || ARCH_OMAP2) > > > > drop the ' && !(ARCH_MX3 || ARCH_OMAP2)' and just let people run into the > > resulting undefined instruction traps if they try to run the kernel on > > V6 non-K hardware. Not ideal, but I don't see any other 'simple' solution > > to this. > > This should be good enough. We're looking for a temporary stopgate > solution to prevent people from corrupting their data, and the real fix > will be available in the next kernel. OK. This patch will be needed anyways for the real fixes. And no temporary apply-undo type patching needed. The only drawback is that omap2420 and 2430 won't boot with omap2plus_defconfig, but that will be only for a few weeks. Acked-by: Tony Lindgren