From patchwork Thu Mar 19 18:19:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 11447841 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5E8101668 for ; Thu, 19 Mar 2020 18:20:10 +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 3AB7A20724 for ; Thu, 19 Mar 2020 18:20:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="seglTGHD"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="gZEbou2C" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3AB7A20724 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.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:To:From:Subject:References:Mime-Version :Message-Id:In-Reply-To:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=TqYvmXQuvUZidH4mqCqXBnn76dneyLWIrHTb1H3eFrM=; b=seglTGHDIDi5nQ OoOo70lLv2euFvtWkGkDJLyzCJVhTlexjJsxdzsPND6AUJ6tzNbn3I5pZk7Vz7vlOErTvjgFWBYb3 LE8fMIG6RRgXITH6a6/SazKqY4aXr4tAVRUca+iizEZjdD1P6Hkh53P9jnpvaYFBowhOCbFJjTdBs T8kzpTH3DtU06KBfkZuFEGgxUUeE/oK14UFRwS4Oa1n8Cln0pFxZduBsHYEXnV7yOMz3ekkU8EYzx htaWpV0ih/f9XbsWximQSqn7ff3P4LvGDrtH2XBbKjNQTQtMhSHyjGdFxBMfQ+6RwAZX02vvypiYN sRHmOiDetu1iPFp2YpnA==; 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 1jEzm3-0006sw-IC; Thu, 19 Mar 2020 18:20:07 +0000 Received: from mail-pf1-x44a.google.com ([2607:f8b0:4864:20::44a]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jEzm1-0006It-5V for linux-arm-kernel@lists.infradead.org; Thu, 19 Mar 2020 18:20:06 +0000 Received: by mail-pf1-x44a.google.com with SMTP id o5so2423214pfp.0 for ; Thu, 19 Mar 2020 11:20:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=5P5en98KHUaK2c9M1pt238mEzcEaVTQjW087IgSolEA=; b=gZEbou2CFuaRnaBVs6VGbGvdKyHSc6hsxdOHqe41Rv9utlPQNEjMrL6T6vvkHx37Cu /vHX5EuZNvKik3a3u20F2MrAuKaFQ7nxZTmc/1pMUDms/2LcMvNAulNc9MqMQ1h3jfEH UZV6MxnTTmdOPAuoyoLtVG6Re13YairDdP2toVomRVYRKKbVCGNyIO1X7B/V/6Kfh8/5 kgtOtfjp6DYF3GzXFXAMY6+rJ9myyxOSSfr1ogAJ6n3Fmahpl1DYb3UEkKhBE8z/jyVq ZEJBZX9KLq5slu9ikq2GFdltBeFk2GOnEa92fAimmySPEkyjAbw+0n9YEIhYxutbpTEY 0DLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=5P5en98KHUaK2c9M1pt238mEzcEaVTQjW087IgSolEA=; b=qU5G/aw0W7qXqbT4BFi9W5qj83ab8iC0kg3w3LC130zg/+yNhDim1aQP28DRfrorNs kbQh0L7v1Es+66NXXeGjMFVdB+l/a7dFpwhZ5LimBkrpTz4LqEDEKTjIxgguUvy5Zezt 4lkyabqB1bS9AwpnNp9fpognKN5foJi9i0DRS88OGhhdMwd/fYQ1VEtjioSseG1+7x2i o+2BpuCLovmq4N9c9ewuxti1SF5OFqKnNv2DagbGLan/G17SzstOVELPU6o5AH6st3XX XUu1ZB8S962D5i8+mluFxasnrnn24+UuCmgjRNpiXPJ66l3PcA8xugG1qb6u0c58MOoc 4uGQ== X-Gm-Message-State: ANhLgQ272N/E+VzujgblAPbOP3vCONtU27DWO9f/+g8YRq2D6jPb54Lp cN7lAiONqjzfZiR8lFFnyZ2GUEA0Dt0az24FwKQ= X-Google-Smtp-Source: ADFU+vuZ2bD3gmRBQWRDXcfM3W9Vv2K6blc9+iR8Eairy2ZQkUXysQBJOhnJDtDqunIO1wLRZLRmERhHq+7ZLmHVD/o= X-Received: by 2002:a17:90a:af81:: with SMTP id w1mr5234832pjq.14.1584642003433; Thu, 19 Mar 2020 11:20:03 -0700 (PDT) Date: Thu, 19 Mar 2020 11:19:51 -0700 In-Reply-To: <1584090304-18043-17-git-send-email-amit.kachhap@arm.com> Message-Id: <20200319181951.102662-1-ndesaulniers@google.com> Mime-Version: 1.0 References: <1584090304-18043-17-git-send-email-amit.kachhap@arm.com> X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH] arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH From: Nick Desaulniers To: catalin.marinas@arm.com, will@kernel.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200319_112005_250239_6C523CD4 X-CRM114-Status: UNSURE ( 9.95 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -7.7 (-------) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-7.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:44a listed in] [list.dnswl.org] -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM white-list -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.0 DKIMWL_WL_MED DKIMwl.org - Medium sender 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@arm.com, keescook@chromium.org, suzuki.poulose@arm.com, Nick Desaulniers , kristina.martsenko@arm.com, ardb@kernel.org, yamada.masahiro@socionext.com, broonie@kernel.org, james.morse@arm.com, clang-built-linux@googlegroups.com, ramana.radhakrishnan@arm.com, amit.kachhap@arm.com, vincenzo.frascino@arm.com, Dave.Martin@arm.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Clang relies on GNU as from binutils to assemble the Linux kernel, currently. A recent patch to enable the armv8.3-a extension for pointer authentication checked for compiler support of the relevant flags. Everything works with binutils 2.34+, but for older versions we observe assembler errors: /tmp/vgettimeofday-36a54b.s: Assembler messages: /tmp/vgettimeofday-36a54b.s:40: Error: unknown pseudo-op: `.cfi_negate_ra_state' When compiling with Clang, require the assembler to support .cfi_negate_ra_state directives, in order to support CONFIG_ARM64_PTR_AUTH. Link: https://github.com/ClangBuiltLinux/linux/issues/938 Signed-off-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor --- Tested with binutils 2.33.1 and ToT. Boot tested in QEMU. I added this requirement only for Clang. GCC maybe doesn't produce these assembler directives, or looks like GCC 8.2 produces .cfi_window_save (https://godbolt.org/z/awZWZ5, godbolt doesn't have a newer aarch64-linux-gnu-gcc...) instead of .cfi_negate_ra_state. Maybe ARM can sort out the inconsistency between compilers? If we plan to add .cfi_negate_ra_state to out of line assembly, we may want to make AS_HAS_CFI_NEGATE_RA_STATE a hard requirement, regardless of compiler. Also, rather than CC_IS_GCC, we could do !CC_IS_CLANG || ... arch/arm64/Kconfig | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b889d7956abf..1ee1d8fab218 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1506,6 +1506,7 @@ config ARM64_PTR_AUTH default y depends on !KVM || ARM64_VHE depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC + depends on CC_IS_GCC || (CC_IS_CLANG && AS_HAS_CFI_NEGATE_RA_STATE) depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) help Pointer authentication (part of the ARMv8.3 Extensions) provides @@ -1550,6 +1551,9 @@ config CC_HAS_SIGN_RETURN_ADDRESS config AS_HAS_PAC def_bool $(as-option,-Wa$(comma)-march=armv8.3-a) +config AS_HAS_CFI_NEGATE_RA_STATE + def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n) + endmenu menu "ARMv8.4 architectural features"