Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933060AbaLDVPQ (ORCPT ); Thu, 4 Dec 2014 16:15:16 -0500 Received: from mail-vc0-f175.google.com ([209.85.220.175]:35738 "EHLO mail-vc0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932845AbaLDVPN (ORCPT ); Thu, 4 Dec 2014 16:15:13 -0500 MIME-Version: 1.0 X-Originating-IP: [2620:0:1000:157d:8d6d:5f31:5f6:cc86] In-Reply-To: <1417707993-82290-1-git-send-email-agraf@suse.de> References: <1417707993-82290-1-git-send-email-agraf@suse.de> Date: Thu, 4 Dec 2014 13:15:12 -0800 Message-ID: Subject: Re: [PATCH] arm64: Enable CONFIG_COMPAT also for 64k page size From: Olof Johansson To: Alexander Graf Cc: "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Will Deacon , Catalin Marinas Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 4, 2014 at 7:46 AM, Alexander Graf wrote: > With binutils 2.25 the default alignment for 32bit arm sections changed to > have everything 64k aligned. Armv7 binaries built with this binutils version > run successfully on an arm64 system. > > Since effectively there is now the chance to run armv7 code on arm64 even > with 64k page size, it doesn't make sense to block people from enabling > CONFIG_COMPAT on those configurations. > > Signed-off-by: Alexander Graf > --- > arch/arm64/Kconfig | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 9532f8d..3cf4f238 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -409,7 +409,6 @@ source "fs/Kconfig.binfmt" > > config COMPAT > bool "Kernel support for 32-bit EL0" > - depends on !ARM64_64K_PAGES > select COMPAT_BINFMT_ELF > select HAVE_UID16 > select OLD_SIGSUSPEND3 This is hardly "compat". Sure, it's great to have a new binutils that has larger alignment, but practically not a single existing binary will work today if someone tries to do this. So, it seems very premature to take this off. At the very least document it like Will requested, and make it depend on !ARM_64K_PAGES || EXPERT. -Olof -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/