Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753116AbbKQO6x (ORCPT ); Tue, 17 Nov 2015 09:58:53 -0500 Received: from eu-smtp-delivery-143.mimecast.com ([207.82.80.143]:39626 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751903AbbKQO6v convert rfc822-to-8bit (ORCPT ); Tue, 17 Nov 2015 09:58:51 -0500 Subject: Re: [PATCH v7 0/4] KASAN for arm64 To: Andrey Ryabinin References: <1444665180-301-1-git-send-email-ryabinin.a.a@gmail.com> <20151013083432.GG6320@e104818-lin.cambridge.arm.com> <5649BAFD.6030005@arm.com> <5649F783.40109@gmail.com> Cc: Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Yury , Alexey Klimov , Arnd Bergmann , linux-mm@kvack.org, Andrey Konovalov , Linus Walleij , Ard Biesheuvel , linux-kernel@vger.kernel.org, kasan-dev , David Keitel , Alexander Potapenko , Dmitry Vyukov From: "Suzuki K. Poulose" Message-ID: <564B40A7.1000206@arm.com> Date: Tue, 17 Nov 2015 14:58:47 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <5649F783.40109@gmail.com> X-OriginalArrivalTime: 17 Nov 2015 14:58:47.0753 (UTC) FILETIME=[765B9390:01D12148] X-MC-Unique: slCGmSRwTa68YEKrlTa5mA-1 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2354 Lines: 70 On 16/11/15 15:34, Andrey Ryabinin wrote: > On 11/16/2015 02:16 PM, Suzuki K. Poulose wrote: >> On 13/10/15 09:34, Catalin Marinas wrote: >>> On Mon, Oct 12, 2015 at 06:52:56PM +0300, Andrey Ryabinin wrote: >> Hi, >> >> I get the following failure with KASAN + 16K_PAGES + 48BIT_VA, with 4.4-rc1: >> >> >> arch/arm64/mm/kasan_init.c: In function ?kasan_early_init?: >> include/linux/compiler.h:484:38: error: call to ?__compiletime_assert_95? declared with attribute error: BUILD_BUG_ON failed: !IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE) >> _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) >> ^ ... > > Yes, it's really needed, because some code relies on this (e.g. clear_pgs() and kasan_init()). > But it should be possible to get rid of this requirement. And the other important point I missed mentioning was that, my tool chain doesn't support KASAN. But still the KASAN support files are still compiled and generates the above error. Shouldn't we disable it at build time if we detect that compiler doesn't support it ? Something like we do for LSE_ATOMICS. commit c09d6a04d17d730b0463207a26ece082772b59ee Author: Will Deacon Date: Tue Feb 3 16:14:13 2015 +0000 arm64: atomics: patch in lse instructions when supported by the CPU On CPUs which support the LSE atomic instructions introduced in ARMv8.1, it makes sense to use them in preference to ll/sc sequences. ... diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 0953a97..15ff5b4 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -17,7 +17,18 @@ GZFLAGS :=-9 KBUILD_DEFCONFIG := defconfig -KBUILD_CFLAGS += -mgeneral-regs-only +# Check for binutils support for specific extensions +lseinstr := $(call as-instr,.arch_extension lse,-DCONFIG_AS_LSE=1) + +ifeq ($(CONFIG_ARM64_LSE_ATOMICS), y) + ifeq ($(lseinstr),) +$(warning LSE atomics not supported by binutils) + endif +endif + +KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) +KBUILD_AFLAGS += $(lseinstr) + Thanks Suzuki -- 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/