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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 BF0EEC433DB for ; Tue, 12 Jan 2021 11:48:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C9E723109 for ; Tue, 12 Jan 2021 11:48:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731116AbhALLsT (ORCPT ); Tue, 12 Jan 2021 06:48:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726999AbhALLsQ (ORCPT ); Tue, 12 Jan 2021 06:48:16 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2F22C061575 for ; Tue, 12 Jan 2021 03:47:35 -0800 (PST) Received: from zn.tnic (p200300ec2f0e8c0026b5c8bc02f060b7.dip0.t-ipconnect.de [IPv6:2003:ec:2f0e:8c00:26b5:c8bc:2f0:60b7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 9613B1EC05BC; Tue, 12 Jan 2021 12:47:33 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1610452053; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=9ZHI8nF07rcMZHB/X81pRY/jX50+4Tbgi/vtsI2OQw4=; b=SvGQcJ9YyY5ZSTBSqmpVID/OAZ+N6a4BgZVQ4VRFB0KWfKjGD8PEPRA/o5Ue/G6SYp9NwO iEt6ZUr4tc0tyAu9PNE+3qw84RX3xbAKJ2DYc1AIl/NMj7OuP+CUrfunfxXo9Zwx/zKDIo yvmjguUmGJR1wqeJN7hVAEEj7FF41f0= Date: Tue, 12 Jan 2021 12:47:25 +0100 From: Borislav Petkov To: Nick Desaulniers Cc: =?utf-8?B?RsSBbmctcnXDrCBTw7JuZw==?= , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Arnd Bergmann , Josh Poimboeuf , X86 ML , "H. Peter Anvin" , Nathan Chancellor , LKML , clang-built-linux Subject: Re: [PATCH v3] x86/entry: emit a symbol for register restoring thunk Message-ID: <20210112114725.GA13086@zn.tnic> References: <20210106015810.5p6crnh7jqtmjtv4@treble> <20210111203807.3547278-1-ndesaulniers@google.com> <20210112003839.GL25645@zn.tnic> <20210112010010.GA8239@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 11, 2021 at 05:13:16PM -0800, Nick Desaulniers wrote: > Unconditionally. See > https://sourceware.org/pipermail/binutils/2021-January/114700.html > where that flag was rejected and the optimization was adopted as the > optimization was obvious to GNU binutils developers. So I suspect this > will become a problem for GNU binutils users as well after the latest > release that contains > https://sourceware.org/pipermail/binutils/attachments/20210105/75dd4a9d/attachment-0001.bin. Aha, thanks for this. > I can clean that up in v5; The section symbols were not generated then > stripped; they were simply never generated. I'd appreciate a more verbose writeup explaining why this is being done, but written for outsiders who are not necessarily toolchain developers. So that it is clear months/years from now why this was done. Something structured like this maybe: Problem is A. It happens because of B. Fix it by doing C. (Potentially do D). Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette