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=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 EB61CC433DB for ; Tue, 16 Mar 2021 14:02:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1A8D6506E for ; Tue, 16 Mar 2021 14:02:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235761AbhCPOCY (ORCPT ); Tue, 16 Mar 2021 10:02:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:59576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235627AbhCPOCR (ORCPT ); Tue, 16 Mar 2021 10:02:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C9FF26506A; Tue, 16 Mar 2021 14:02:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615903335; bh=i16G61MjWsPoU5as8xHDp+00TirP+H6Y7rzzM6KXU0M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oFwZBmekbBVpdNl/bGqUoaWdFNL67i0tv9ARgLly4fs+NPrW/DMXHwWOyo62JeLex XA4kXkcp1kwWVq7cHdYE36G29eaZ65FpGWQd60lh84litlZNa6oduhVuSYhE2DqwzT BrYaCyAM1fQ4qpB1dEx6m9kgXvZzvU00cemEQ8XeK4UQJaZlLjBC48Gy+WEhGe1H4I xsFXMDH5iIcjtq63xzMUpKQKXYHUokiAwjWUHrX7g8bV2dJg+76CXI4WsIrkCxg3a7 DdlFT7xRCCTAtUnYeO1pZOJEscmBwNojtpHdw+6v4ka6rTSpaBVfvrpE4OFbWSnqNE FOnI+s4S6OA8w== Date: Tue, 16 Mar 2021 10:02:13 -0400 From: Sasha Levin To: Nick Desaulniers Cc: Ard Biesheuvel , Greg KH , "# 3.4.x" , clang-built-linux , Jian Cai , Stefan Agner , Catalin Marinas , Sami Tolvanen , candle.sun@unisoc.com, Miles Chen =?utf-8?B?KOmZs+awkeaouik=?= , Stephen Hines , Luis Lozano , Sandeep Patil , Marc Zyngier Subject: Re: ARCH=arm LLVM_IAS=1 patches for 5.10, 5.4, and 4.19 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Mar 15, 2021 at 03:58:07PM -0700, Nick Desaulniers wrote: >On Mon, Mar 15, 2021 at 10:53 AM Ard Biesheuvel wrote: >> You haven't explained why all this effort is justified to begin with. >> >> Who cares about being able to build 4.19 or 5.4 mainline with Clang 12 >> and IAS? > >Ah, sorry, ChromeOS and Android very much do so. (Google's production >kernels as well, though I don't think they have any 32b ARM machines). >Android is already building 4.19+ with LLVM_IAS=1 for >ARCH=arm64,x86_64,i686. ChromeOS is doing so for 5.4+ for >ARCH=arm64,x86_64 as well. I'm not sure precisely what's going on in >prodkernel land, but I know they have LLVM_IAS=1 enabled for x86_64. >So when Greg says this is "for no real users" I disagree. Maybe no >one is using LLVM_IAS=1 for ARCH=arm at this moment, but that was the >point of the backports, to enable more distros to do so. You can't both stay on a "stable" kernel because it's "stable", but then expect a flow of new features. The users which you've mentioned should be migrating to newer kernels instead of attempting to backport features they care about to stable kernels. -- Thanks, Sasha