From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752934AbeCTLFi (ORCPT ); Tue, 20 Mar 2018 07:05:38 -0400 Received: from terminus.zytor.com ([198.137.202.136]:40627 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752873AbeCTLF0 (ORCPT ); Tue, 20 Mar 2018 07:05:26 -0400 Date: Tue, 20 Mar 2018 04:03:47 -0700 From: "tip-bot for H.J. Lu" Message-ID: Cc: jgross@suse.com, mingo@kernel.org, kirill.shutemov@linux.intel.com, tglx@linutronix.de, torvalds@linux-foundation.org, andy.shevchenko@gmail.com, ebiederm@xmission.com, keescook@chromium.org, hpa@zytor.com, linux-kernel@vger.kernel.org, hjl.tools@gmail.com, peterz@infradead.org Reply-To: keescook@chromium.org, hpa@zytor.com, ebiederm@xmission.com, torvalds@linux-foundation.org, tglx@linutronix.de, andy.shevchenko@gmail.com, jgross@suse.com, kirill.shutemov@linux.intel.com, mingo@kernel.org, peterz@infradead.org, hjl.tools@gmail.com, linux-kernel@vger.kernel.org In-Reply-To: References: To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/build/64: Force the linker to use 2MB page size Git-Commit-ID: e3d03598e8ae7d195af5d3d049596dec336f569f X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: e3d03598e8ae7d195af5d3d049596dec336f569f Gitweb: https://git.kernel.org/tip/e3d03598e8ae7d195af5d3d049596dec336f569f Author: H.J. Lu AuthorDate: Mon, 19 Mar 2018 13:57:46 -0700 Committer: Ingo Molnar CommitDate: Tue, 20 Mar 2018 08:03:03 +0100 x86/build/64: Force the linker to use 2MB page size Binutils 2.31 will enable -z separate-code by default for x86 to avoid mixing code pages with data to improve cache performance as well as security. To reduce x86-64 executable and shared object sizes, the maximum page size is reduced from 2MB to 4KB. But x86-64 kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to linker to force 2MB page size regardless of the default page size used by linker. Tested with Linux kernel 4.15.6 on x86-64. Signed-off-by: H.J. Lu Cc: Andy Shevchenko Cc: Eric Biederman Cc: H. Peter Anvin Cc: Juergen Gross Cc: Kees Cook Cc: Kirill A. Shutemov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/CAMe9rOp4_%3D_8twdpTyAP2DhONOCeaTOsniJLoppzhoNptL8xzA@mail.gmail.com Signed-off-by: Ingo Molnar --- arch/x86/Makefile | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 498c1b812300..1c4d012550ec 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -223,6 +223,15 @@ KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) LDFLAGS := -m elf_$(UTS_MACHINE) +# +# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to +# the linker to force 2MB page size regardless of the default page size used +# by the linker. +# +ifdef CONFIG_X86_64 +LDFLAGS += $(call ld-option, -z max-page-size=0x200000) +endif + # Speed up the build KBUILD_CFLAGS += -pipe # Workaround for a gcc prelease that unfortunately was shipped in a suse release