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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 D79F8C433E0 for ; Wed, 24 Jun 2020 23:51:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1AE22078E for ; Wed, 24 Jun 2020 23:51:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388105AbgFXXvp (ORCPT ); Wed, 24 Jun 2020 19:51:45 -0400 Received: from mga02.intel.com ([134.134.136.20]:34743 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387959AbgFXXvp (ORCPT ); Wed, 24 Jun 2020 19:51:45 -0400 IronPort-SDR: 6bUtqBjrs5r3Q6hd6HO10rsF2QBhhBW7nqIP4BFE5JSMtcGkS+AUvjdbRAIpjSJkLnxv9bRI6F HHlRGb+LAKKQ== X-IronPort-AV: E=McAfee;i="6000,8403,9662"; a="133107161" X-IronPort-AV: E=Sophos;i="5.75,277,1589266800"; d="scan'208";a="133107161" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2020 16:51:44 -0700 IronPort-SDR: aIRwRfjfYOdQKt3phW/InEgXxtOGI/IQstcHLZdz056+zuNv6rXZAztOwLlpT5Cd5ScDQD9lHH /YX4kqyPmgHA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,277,1589266800"; d="scan'208";a="423544015" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.21]) by orsmga004.jf.intel.com with ESMTP; 24 Jun 2020 16:51:44 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 463F2301BA1; Wed, 24 Jun 2020 16:51:44 -0700 (PDT) Date: Wed, 24 Jun 2020 16:51:44 -0700 From: Andi Kleen To: Nick Desaulniers Cc: Sami Tolvanen , Masahiro Yamada , Will Deacon , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , clang-built-linux , Kernel Hardening , linux-arch , Linux ARM , Linux Kbuild mailing list , LKML , linux-pci@vger.kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Subject: Re: [PATCH 17/22] arm64: vdso: disable LTO Message-ID: <20200624235144.GD818054@tassilo.jf.intel.com> References: <20200624203200.78870-1-samitolvanen@google.com> <20200624203200.78870-18-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Jun 24, 2020 at 02:09:40PM -0700, Nick Desaulniers wrote: > On Wed, Jun 24, 2020 at 1:58 PM Nick Desaulniers > wrote: > > > > On Wed, Jun 24, 2020 at 1:33 PM Sami Tolvanen wrote: > > > > > > Filter out CC_FLAGS_LTO for the vDSO. > > > > Just curious about this patch (and the following one for x86's vdso), > > do you happen to recall specifically what the issues with the vdso's > > are? > > + Andi (tangential, I actually have a bunch of tabs open with slides > from http://halobates.de/ right now) > 58edae3aac9f2 > 67424d5a22124 > $ git log -S DISABLE_LTO I think I did it originally because the vDSO linker step didn't do all the magic needed for gcc LTO. But it also doesn't seem to be very useful for just a few functions that don't have complex interactions, and somewhat risky for violating some assumptions. -Andi