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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 E95ACC43144 for ; Wed, 27 Jun 2018 15:14:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A847D25EDA for ; Wed, 27 Jun 2018 15:14:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A847D25EDA 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-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752592AbeF0POf (ORCPT ); Wed, 27 Jun 2018 11:14:35 -0400 Received: from foss.arm.com ([217.140.101.70]:33138 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751002AbeF0POd (ORCPT ); Wed, 27 Jun 2018 11:14:33 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A5AB718A; Wed, 27 Jun 2018 08:14:33 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 76EB03F266; Wed, 27 Jun 2018 08:14:33 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 5D1101AE3692; Wed, 27 Jun 2018 16:15:11 +0100 (BST) Date: Wed, 27 Jun 2018 16:15:11 +0100 From: Will Deacon To: Ard Biesheuvel Cc: linux-kernel@vger.kernel.org, Arnd Bergmann , Kees Cook , Michael Ellerman , Thomas Garnier , Thomas Gleixner , "Serge E. Hallyn" , Bjorn Helgaas , Benjamin Herrenschmidt , Russell King , Paul Mackerras , Catalin Marinas , Petr Mladek , Ingo Molnar , James Morris , Andrew Morton , Nicolas Pitre , Josh Poimboeuf , Steven Rostedt , Sergey Senozhatsky , Linus Torvalds , Jessica Yu , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org Subject: Re: [PATCH v9 0/6] add support for relative references in special sections Message-ID: <20180627151510.GE30631@arm.com> References: <20180626182802.19932-1-ard.biesheuvel@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180626182802.19932-1-ard.biesheuvel@linaro.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ard, On Tue, Jun 26, 2018 at 08:27:55PM +0200, Ard Biesheuvel wrote: > This adds support for emitting special sections such as initcall arrays, > PCI fixups and tracepoints as relative references rather than absolute > references. This reduces the size by 50% on 64-bit architectures, but > more importantly, it removes the need for carrying relocation metadata > for these sections in relocatable kernels (e.g., for KASLR) that needs > to be fixed up at boot time. On arm64, this reduces the vmlinux footprint > of such a reference by 8x (8 byte absolute reference + 24 byte RELA entry > vs 4 byte relative reference) > > Patch #3 was sent out before as a single patch. This series supersedes > the previous submission. This version makes relative ksymtab entries > dependent on the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS rather > than trying to infer from kbuild test robot replies for which architectures > it should be blacklisted. > > Patch #1 introduces the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS, > and sets it for the main architectures that are expected to benefit the > most from this feature, i.e., 64-bit architectures or ones that use > runtime relocations. > > Patch #2 add support for #define'ing __DISABLE_EXPORTS to get rid of > ksymtab/kcrctab sections in decompressor and EFI stub objects when > rebuilding existing C files to run in a different context. I had a small question on patch 3, but it's really for my understanding. So, for patches 1-3: Reviewed-by: Will Deacon Thanks, Will