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=-16.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 6C50AC43457 for ; Mon, 12 Oct 2020 20:51:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F77A20790 for ; Mon, 12 Oct 2020 20:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602535879; bh=0GkuUU3uNC/spWLd0lGLXk3f0NEQnPHerA+y4i0HfIc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=HfwiiJd360jz9suQhyFIDLlYPgpFkbYksQkwPuYBwJ8wMaYvtLJDS/UzXu3Sp4nsR Kh2/pG2H+NGXp6ImOSGft5GRsFO7Tm9Cd2z5fFzxEgCpAvfkrINDAJwb6g3nIlGYgm hRDKJiB7imYX56RFZCTJsSKibLD1QzQpbA9vWQNM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731338AbgJLUvQ (ORCPT ); Mon, 12 Oct 2020 16:51:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:36684 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726510AbgJLUvQ (ORCPT ); Mon, 12 Oct 2020 16:51:16 -0400 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B24EB2078E; Mon, 12 Oct 2020 20:51:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602535875; bh=0GkuUU3uNC/spWLd0lGLXk3f0NEQnPHerA+y4i0HfIc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aUA4p24mfdDVp8gVMcJs3cg4QcRdzKI2RfnmgjjYH0yIvLOULOXyZL1YYb40RXCIL 0j4QZMJA0d4Jf96ySlvQCMNewtFUSD3KgMkUuWXetoBRKiLSWzbvYrWq0FC+1nMHyw 66F2X0FbdKKOd7lh9w7SiCHjg714ONHZLITlgfQo= Date: Mon, 12 Oct 2020 21:51:09 +0100 From: Will Deacon To: Kees Cook Cc: Sami Tolvanen , Masahiro Yamada , Steven Rostedt , Peter Zijlstra , Greg Kroah-Hartman , "Paul E. McKenney" , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v5 25/29] arm64: allow LTO_CLANG and THINLTO to be selected Message-ID: <20201012205108.GA1620@willie-the-truck> References: <20201009161338.657380-1-samitolvanen@google.com> <20201009161338.657380-26-samitolvanen@google.com> <20201012083116.GA785@willie-the-truck> <202010121344.53780D8CD2@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202010121344.53780D8CD2@keescook> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 12, 2020 at 01:44:56PM -0700, Kees Cook wrote: > On Mon, Oct 12, 2020 at 09:31:16AM +0100, Will Deacon wrote: > > On Fri, Oct 09, 2020 at 09:13:34AM -0700, Sami Tolvanen wrote: > > > Allow CONFIG_LTO_CLANG and CONFIG_THINLTO to be enabled. > > > > > > Signed-off-by: Sami Tolvanen > > > Reviewed-by: Kees Cook > > > --- > > > arch/arm64/Kconfig | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > > index ad522b021f35..7016d193864f 100644 > > > --- a/arch/arm64/Kconfig > > > +++ b/arch/arm64/Kconfig > > > @@ -72,6 +72,8 @@ config ARM64 > > > select ARCH_USE_SYM_ANNOTATIONS > > > select ARCH_SUPPORTS_MEMORY_FAILURE > > > select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK > > > + select ARCH_SUPPORTS_LTO_CLANG > > > + select ARCH_SUPPORTS_THINLTO > > > > Please don't enable this for arm64 until we have the dependency stuff sorted > > out. I posted patches [1] for this before, but I think they should be part > > of this series as they don't make sense on their own. > > Oh, hm. We've been trying to trim down this series, since it's already > quite large. Why can't [1] land first? It would make this easier to deal > with, IMO. I'm happy to handle [1] along with the LTO Kconfig change when the time comes, if that helps. I just don't want to merge dead code! Will > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=rwonce/read-barrier-depends