From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7448ECE587 for ; Tue, 1 Oct 2019 14:21:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9EFE721855 for ; Tue, 1 Oct 2019 14:21:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388989AbfJAOVy (ORCPT ); Tue, 1 Oct 2019 10:21:54 -0400 Received: from foss.arm.com ([217.140.110.172]:50742 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388942AbfJAOVx (ORCPT ); Tue, 1 Oct 2019 10:21:53 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9DB641570; Tue, 1 Oct 2019 07:21:52 -0700 (PDT) Received: from [10.37.8.149] (unknown [10.37.8.149]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F0F3E3F71A; Tue, 1 Oct 2019 07:21:50 -0700 (PDT) Subject: Re: [PATCH v3 2/5] arm64: vdso32: Detect binutils support for dmb ishld To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, ard.biesheuvel@linaro.org, ndesaulniers@google.com, catalin.marinas@arm.com, tglx@linutronix.de References: <20190920142738.qlsjwguc6bpnez63@willie-the-truck> <20190926214342.34608-1-vincenzo.frascino@arm.com> <20190926214342.34608-3-vincenzo.frascino@arm.com> <20191001132640.plowjzi5nmajs72x@willie-the-truck> From: Vincenzo Frascino Message-ID: Date: Tue, 1 Oct 2019 15:23:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20191001132640.plowjzi5nmajs72x@willie-the-truck> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/1/19 2:26 PM, Will Deacon wrote: > On Thu, Sep 26, 2019 at 10:43:39PM +0100, Vincenzo Frascino wrote: >> As reported by Will Deacon, older versions of binutils that do not >> support certain types of memory barriers can cause build failure of the >> vdso32 library. >> >> Add a compilation time mechanism that detects if binutils supports those >> instructions and configure the kernel accordingly. >> >> Cc: Will Deacon >> Cc: Catalin Marinas >> Signed-off-by: Vincenzo Frascino >> --- >> arch/arm64/include/asm/vdso/compat_barrier.h | 2 +- >> arch/arm64/kernel/vdso32/Makefile | 9 +++++++++ >> 2 files changed, 10 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm64/include/asm/vdso/compat_barrier.h b/arch/arm64/include/asm/vdso/compat_barrier.h >> index fb60a88b5ed4..3fd8fd6d8fc2 100644 >> --- a/arch/arm64/include/asm/vdso/compat_barrier.h >> +++ b/arch/arm64/include/asm/vdso/compat_barrier.h >> @@ -20,7 +20,7 @@ >> >> #define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory") >> >> -#if __LINUX_ARM_ARCH__ >= 8 >> +#if __LINUX_ARM_ARCH__ >= 8 && defined(CONFIG_AS_DMB_ISHLD) >> #define aarch32_smp_mb() dmb(ish) >> #define aarch32_smp_rmb() dmb(ishld) >> #define aarch32_smp_wmb() dmb(ishst) >> diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile >> index 19e0d3115ffe..77aa61340374 100644 >> --- a/arch/arm64/kernel/vdso32/Makefile >> +++ b/arch/arm64/kernel/vdso32/Makefile >> @@ -15,6 +15,8 @@ cc32-disable-warning = $(call try-run,\ >> $(COMPATCC) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) >> cc32-ldoption = $(call try-run,\ >> $(COMPATCC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) >> +cc32-as-instr = $(call try-run,\ >> + printf "%b\n" "$(1)" | $(COMPATCC) $(VDSO_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) > > It's a shame that we have to duplicate the logic from scripts/Kbuild.include > here. Is there a way to reuse those helpers by temporarily overriding things > like CC and KBUILD_AFLAGS? If not, no bother, but thought I'd better ask. > I tried to define a rule in scripts/Kbuild.include at the beginning doing what you are saying but I could not end up with a working solution, hence I ended up with a dedicated one. > Will > -- Regards, Vincenzo