Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966839AbcKXPbU (ORCPT ); Thu, 24 Nov 2016 10:31:20 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:57910 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966830AbcKXP2v (ORCPT ); Thu, 24 Nov 2016 10:28:51 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Borislav Petkov , Ben Hutchings , Sebastian Andrzej Siewior , Michal Marek Subject: [PATCH 4.8 25/67] kbuild: Steal gccs pie from the very beginning Date: Thu, 24 Nov 2016 16:27:19 +0100 Message-Id: <20161124145458.955388517@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161124145457.061710350@linuxfoundation.org> References: <20161124145457.061710350@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2387 Lines: 67 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Borislav Petkov commit c6a385539175ebc603da53aafb7753d39089f32e upstream. So Sebastian turned off the PIE for kernel builds but that was too late - Kbuild.include already uses KBUILD_CFLAGS and trying to disable gcc options with, say cc-disable-warning, fails: gcc -D__KERNEL__ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs ... -Wno-sign-compare -fno-asynchronous-unwind-tables -Wframe-address -c -x c /dev/null -o .31392.tmp /dev/null:1:0: error: code model kernel does not support PIC mode because that returns an error and we can't disable the warning. For example in this case: KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,) which leads to gcc issuing all those warnings again. So let's turn off PIE/PIC at the earliest possible moment, when we declare KBUILD_CFLAGS so that cc-disable-warning picks it up too. Also, we need the $(call cc-option ...) because -fno-PIE is supported since gcc v3.4 and our lowest supported gcc version is 3.2 right now. Signed-off-by: Borislav Petkov Cc: Ben Hutchings Cc: Sebastian Andrzej Siewior Signed-off-by: Michal Marek Signed-off-by: Greg Kroah-Hartman --- Makefile | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/Makefile +++ b/Makefile @@ -399,11 +399,12 @@ KBUILD_CFLAGS := -Wall -Wundef -Wstric -fno-strict-aliasing -fno-common \ -Werror-implicit-function-declaration \ -Wno-format-security \ - -std=gnu89 + -std=gnu89 $(call cc-option,-fno-PIE) + KBUILD_AFLAGS_KERNEL := KBUILD_CFLAGS_KERNEL := -KBUILD_AFLAGS := -D__ASSEMBLY__ +KBUILD_AFLAGS := -D__ASSEMBLY__ $(call cc-option,-fno-PIE) KBUILD_AFLAGS_MODULE := -DMODULE KBUILD_CFLAGS_MODULE := -DMODULE KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds @@ -622,8 +623,6 @@ include arch/$(SRCARCH)/Makefile KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,) KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,) -KBUILD_CFLAGS += $(call cc-option,-fno-PIE) -KBUILD_AFLAGS += $(call cc-option,-fno-PIE) ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += -Os