From patchwork Mon Feb 17 20:30:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 11387563 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 272BA14E3 for ; Mon, 17 Feb 2020 20:30:59 +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 F3DC320836 for ; Mon, 17 Feb 2020 20:30:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="biJmdCsX"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="lUjfK6z8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F3DC320836 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=KBda6WrEA99tDhLqp+T+mYtq8CKdW/df5LQJvuj8QPc=; b=biJ mdCsXS5o4IBs3U6GUbScM9sc1WT2AyGbFT4FFnLtqUtGhGAC/5POuDN59hPEBzIbzAnAExiaAqQ81 8g+runV05dW1gYNWxBxw0rBpt321bpekwI1O4V0IvqLf52jmbTnEGowGAQrnBjk/R5wfExGUrjvL9 yd832ez2MPzb+mXhsYdL+pZaJ6sMIRF8KINm9Bm1lAW2JVARWGKn3uqpUe8d5phQa+4Z1qMzY9n5w z2Q5J/Qrpgo7qugzZB8to7NOkRCaniggzsKyD4W6lFv7ZEcysMkpEZWKy6NQJVxzTdCZdCdFpFJzZ NOqnfnZ5/N5dvrQFAJgdGu4OT8GkUgg==; 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 1j3n2b-00043x-To; Mon, 17 Feb 2020 20:30:53 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1j3n2Z-00042C-8R for linux-arm-kernel@lists.infradead.org; Mon, 17 Feb 2020 20:30:52 +0000 Received: from cam-smtp0.cambridge.arm.com (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6DE29207FD; Mon, 17 Feb 2020 20:30:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581971450; bh=SGQhgmuE1tkSZXILdSCmd2w9MGVUjjgoyJm9PODUW/w=; h=From:To:Cc:Subject:Date:From; b=lUjfK6z8//vPe6YoZPmknX2Q4DOtS3kwGZ6yfqE88PtArImv47OczZamJsFaCrljL aSDvj29HxqCrBpH/zCDyexzTZ0FiAFkoRLzP70uKWym02jM8V9hg3V1YmV/iqd9VRk Uqc8SGhN9pGpFx24Qig3JROweuGPPRwqXXvIz/Ck= From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm: fix Kbuild issue caused by per-task stack protector GCC plugin Date: Mon, 17 Feb 2020 21:30:13 +0100 Message-Id: <20200217203013.20102-1-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200217_123051_344388_4FCA4B18 X-CRM114-Status: GOOD ( 16.38 ) X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -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 Message has at least one valid DKIM or DK signature -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High 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: Kees Cook , Arnd Bergmann , tony@atomide.com, Russell King , Masahiro Yamada , Ard Biesheuvel MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org When using plugins, GCC requires that the -fplugin= options precedes any of its plugin arguments appearing on the command line as well. This is usually not a concern, but as it turns out, this requirement is causing some issues with ARM's per-task stack protector plugin and Kbuild's implementation of $(cc-option). When the per-task stack protector plugin is enabled, and we tweak the implementation of cc-option not to pipe the stderr output of GCC to /dev/null, the following output is generated when GCC is executed in the context of cc-option: cc1: error: plugin arm_ssp_per_task_plugin should be specified before \ -fplugin-arg-arm_ssp_per_task_plugin-tso=1 in the command line cc1: error: plugin arm_ssp_per_task_plugin should be specified before \ -fplugin-arg-arm_ssp_per_task_plugin-offset=24 in the command line These errors will cause any option passed to cc-option to be treated as unsupported, which is obviously incorrect. The cause of this issue is the fact that the -fplugin= argument is added to GCC_PLUGINS_CFLAGS, whereas the arguments above are added to KBUILD_CFLAGS, and the contents of the former get filtered out of the latter before being passed to the GCC running the cc-option test, and so the -fplugin= option does not appear at all on the GCC command line. Adding the arguments to GCC_PLUGINS_CFLAGS instead of KBUILD_CFLAGS would be the correct approach here, if it weren't for the fact that we are using $(eval) to defer the moment that they are added until after asm-offsets.h is generated, which is after the point where the contents of GCC_PLUGINS_CFLAGS are added to KBUILD_CFLAGS. So instead, we have to add our plugin arguments to both. For similar reasons, we cannot append DISABLE_ARM_SSP_PER_TASK_PLUGIN to KBUILD_CFLAGS, as it will be passed to GCC when executing in the context of cc-option, whereas the other plugin arguments will have been filtered out, resulting in a similar error and false negative result as above. So add it to ccflags-y instead. Reported-by: Tony Lindgren Fixes: 189af4657186da08 ("ARM: smp: add support for per-task stack canaries") Cc: Kees Cook Cc: Russell King Cc: Arnd Bergmann Cc: Masahiro Yamada Signed-off-by: Ard Biesheuvel Tested-by: Tony Lindgren Reported-by: Merlijn Wajer Acked-by: Kees Cook Reviewed-by: Masahiro Yamada --- arch/arm/Makefile | 4 +++- arch/arm/boot/compressed/Makefile | 4 ++-- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/arm/Makefile b/arch/arm/Makefile index db857d07114f..1fc32b611f8a 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -307,13 +307,15 @@ endif ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y) prepare: stack_protector_prepare stack_protector_prepare: prepare0 - $(eval KBUILD_CFLAGS += \ + $(eval SSP_PLUGIN_CFLAGS := \ -fplugin-arg-arm_ssp_per_task_plugin-tso=$(shell \ awk '{if ($$2 == "THREAD_SZ_ORDER") print $$3;}'\ include/generated/asm-offsets.h) \ -fplugin-arg-arm_ssp_per_task_plugin-offset=$(shell \ awk '{if ($$2 == "TI_STACK_CANARY") print $$3;}'\ include/generated/asm-offsets.h)) + $(eval KBUILD_CFLAGS += $(SSP_PLUGIN_CFLAGS)) + $(eval GCC_PLUGINS_CFLAGS += $(SSP_PLUGIN_CFLAGS)) endif all: $(notdir $(KBUILD_IMAGE)) diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index da599c3a1193..9c11e7490292 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -101,7 +101,6 @@ clean-files += piggy_data lib1funcs.S ashldi3.S bswapsdi2.S \ $(libfdt) $(libfdt_hdrs) hyp-stub.S KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING -KBUILD_CFLAGS += $(DISABLE_ARM_SSP_PER_TASK_PLUGIN) ifeq ($(CONFIG_FUNCTION_TRACER),y) ORIG_CFLAGS := $(KBUILD_CFLAGS) @@ -117,7 +116,8 @@ CFLAGS_fdt_ro.o := $(nossp-flags-y) CFLAGS_fdt_rw.o := $(nossp-flags-y) CFLAGS_fdt_wip.o := $(nossp-flags-y) -ccflags-y := -fpic $(call cc-option,-mno-single-pic-base,) -fno-builtin -I$(obj) +ccflags-y := -fpic $(call cc-option,-mno-single-pic-base,) -fno-builtin \ + -I$(obj) $(DISABLE_ARM_SSP_PER_TASK_PLUGIN) asflags-y := -DZIMAGE # Supply kernel BSS size to the decompressor via a linker symbol.