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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 02643C47247 for ; Tue, 5 May 2020 14:26:11 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C54692073B for ; Tue, 5 May 2020 14:26:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ilFA6/IL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C54692073B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1HjCT+oe/GhwjRSQWe6Py2kHjN2uhxfIuqmouQK0NAc=; b=ilFA6/ILUPii+1 sEHEI+twNEZ9fAsIJGXcEnVMldYcxvhfn3ndoqOvJ2/rPyUWviqmERnhH9kxZGS8JQTZ12mwaiV6G Cbcn0lYveJFJoJR+RgLcUI2TJVOTkNeEhGoVEC/xDSFXYbMxs2++6G/kJKtxotieZ2RVuVWsUKP/X SSxpzD+kMvdBC70/xSIpsnBXEaFnNYquwUF4iWNLKQhYaihT7lsWkeOWrZtNL0d0WtYp9FAY6Edhi SSS/OOvndgdCLjkDpyrwO11DsMepnArULueDlhsBNfaRA0xag47jlhaxt9QBps7/nLZtrltZqRKPt syXY3odYceBU8ef+t3Lw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jVyWO-0000Xi-Ds; Tue, 05 May 2020 14:26:08 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jVyWL-0000Wn-CG for linux-arm-kernel@lists.infradead.org; Tue, 05 May 2020 14:26:06 +0000 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 CAEE01FB; Tue, 5 May 2020 07:26:03 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.25.241]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 456BF3F68F; Tue, 5 May 2020 07:25:59 -0700 (PDT) Date: Tue, 5 May 2020 15:25:56 +0100 From: Mark Rutland To: Arnd Bergmann Subject: Re: [PATCH] arm64: disable patchable function entry on big-endian clang builds Message-ID: <20200505142556.GF82823@C02TD0UTHF1T.local> References: <20200505141257.707945-1-arnd@arndb.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200505141257.707945-1-arnd@arndb.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200505_072605_463389_CEBC62A1 X-CRM114-Status: GOOD ( 18.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marc Zyngier , Ionela Voinescu , Julien Thierry , Alexandre Ghiti , Ard Biesheuvel , Catalin Marinas , Torsten Duwe , Steve Capper , linux-kernel@vger.kernel.org, Kristina Martsenko , AKASHI Takahiro , Torsten Duwe , clang-built-linux@googlegroups.com, Josh Poimboeuf , Amit Daniel Kachhap , Andrew Morton , Will Deacon , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, Kees Cook Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 05, 2020 at 04:12:36PM +0200, Arnd Bergmann wrote: > Clang only supports the patchable_function_entry attribute on > little-endian arm64 builds, but not on big-endian: > > include/linux/kasan-checks.h:16:8: error: unknown attribute 'patchable_function_entry' ignored [-Werror,-Wunknown-attributes] > > Disable that configuration with another dependency. Unfortunately > the existing check is not enough, as $(cc-option) at this point does > not pass the -mbig-endian flag. Well that's unfortunate. :( Do we know if this is deliberate and/or likely to change in future? This practically rules out a BE distro kernel with things like PAC, which isn't ideal. > Fixes: 3b23e4991fb6 ("arm64: implement ftrace with regs") > Signed-off-by: Arnd Bergmann This looks fine for now, and we can add a version check in future, so: Acked-by: Mark Rutland Mark. > --- > arch/arm64/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 4b256fa6db7a..a33d6402b934 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -151,7 +151,7 @@ config ARM64 > select HAVE_DMA_CONTIGUOUS > select HAVE_DYNAMIC_FTRACE > select HAVE_DYNAMIC_FTRACE_WITH_REGS \ > - if $(cc-option,-fpatchable-function-entry=2) > + if $(cc-option,-fpatchable-function-entry=2) && !(CC_IS_CLANG && CPU_BIG_ENDIAN) > select HAVE_EFFICIENT_UNALIGNED_ACCESS > select HAVE_FAST_GUP > select HAVE_FTRACE_MCOUNT_RECORD > -- > 2.26.0 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel