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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 72692C3F2C6 for ; Tue, 3 Mar 2020 09:28:41 +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 4510520863 for ; Tue, 3 Mar 2020 09:28:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ibhbj+/j" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4510520863 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-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=uTx7dzCNmbObIS1jaa6d3sfHdV6yDxA0OiqMYWEQra4=; b=ibhbj+/jZly3FWRS5fvyYoZC2 +eIPaChK0Hf6xO83GBGnr5jbEhb91yUSJqnUtDDZ3gsYkPgS7GU1ZzwbJ8W2ibjMJ9E/Z5/QQlnJO wJBSiLZ5rBGmN0ZdVDiAiVR1vnJUEzCKoMAhphlCmoGmxg/wjFggCctqGAp+AJGilRu7cIlF1fb19 z7uKIdThmI//Ej+c6rmah861Ngfm0XH8GHYOj6DODjBCV5fMoY31IpVRszD0zvx3auyIz47EDr4jA A0iVxCXBQUrSXL/LgMRuB8WYrUaGLMRZkywwKvVxgfr5M3IWJPGGLGPMJib+eDyI71swACA4ty3Ay Uy0J3s6uw==; 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 1j93qq-0000i4-Na; Tue, 03 Mar 2020 09:28:32 +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 1j93qn-0000h2-03 for linux-arm-kernel@lists.infradead.org; Tue, 03 Mar 2020 09:28:30 +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 23A212F; Tue, 3 Mar 2020 01:28:27 -0800 (PST) Received: from [10.162.16.120] (a075563-lin.blr.arm.com [10.162.16.120]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9CCCD3F6C4; Tue, 3 Mar 2020 01:28:23 -0800 (PST) Subject: Re: [PATCH v5 16/17] arm64: compile the kernel with ptrauth return address signing To: Catalin Marinas References: <1581931668-11559-1-git-send-email-amit.kachhap@arm.com> <1581931668-11559-17-git-send-email-amit.kachhap@arm.com> <20200228182337.GK4019108@arrakis.emea.arm.com> From: Amit Kachhap Message-ID: Date: Tue, 3 Mar 2020 14:58:25 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20200228182337.GK4019108@arrakis.emea.arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200303_012829_084217_33E6A624 X-CRM114-Status: GOOD ( 15.91 ) 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: Mark Rutland , Kees Cook , Suzuki K Poulose , Kristina Martsenko , Dave Martin , Masahiro Yamada , Mark Brown , James Morse , Ramana Radhakrishnan , Vincenzo Frascino , Will Deacon , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2/28/20 11:53 PM, Catalin Marinas wrote: > On Mon, Feb 17, 2020 at 02:57:47PM +0530, Amit Daniel Kachhap wrote: >> +ifeq ($(CONFIG_ARM64_PTR_AUTH),y) >> +branch-prot-flags-$(CONFIG_CC_HAS_SIGN_RETURN_ADDRESS) := -msign-return-address=all >> +branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET) := -mbranch-protection=pac-ret+leaf >> +# -march=armv8.3-a enables the non-nops instructions for PAC, to avoid the compiler >> +# to generate them and consequently to break the single image contract we pass it >> +# only to the assembler when clang is selected as a compiler. For the GNU toolchain >> +# this option is not used. >> +branch-prot-flags-$(CONFIG_AS_HAS_PAC) += -Wa,-march=armv8.3-a >> +KBUILD_CFLAGS += $(branch-prot-flags-y) >> +endif > > Does this work with the clang integrated assembler? AFAIK it ignores the > -Wa, though it may be fine with the instructions generated by the > compiler. (while we don't officially support it, we merged patches to > facilitate it). Clang integrated assembler compiles some initial c files into object files and those contains the ptrauth instructions. As you said it ignores the -Wa flag. > > Also, the above comment says that the -Wa option is used only when > building with clang. I don't see this being the case in the patch above. I will update the comments. > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel