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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 44171C54FCB for ; Sat, 25 Apr 2020 18:53:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F564206ED for ; Sat, 25 Apr 2020 18:53:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="J1HDIxyv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726316AbgDYSxW (ORCPT ); Sat, 25 Apr 2020 14:53:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726145AbgDYSxW (ORCPT ); Sat, 25 Apr 2020 14:53:22 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 154A3C09B04D for ; Sat, 25 Apr 2020 11:53:22 -0700 (PDT) Received: from zn.tnic (p200300EC2F2A1100B46A3E12B0A6AFFD.dip0.t-ipconnect.de [IPv6:2003:ec:2f2a:1100:b46a:3e12:b0a6:affd]) (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 8527F1EC0C84; Sat, 25 Apr 2020 20:53:20 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1587840800; 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=iTbPHyhUCYp1hsTKDTL6Rkak9xj3g4rssRfqZNkVLdA=; b=J1HDIxyv/9Q6KrgTFyzUaS9MzUgSTqUl1CHKzxt9TsfuRWCgenOsqkBAUiSvooHmIFgoYR xTFg4Y4kCmZjWDIrRtDZdBKr0CU76/YyCxbHLM8CBk0vP11S/rVp9yFpSmoUqaXMTtJMbC uoQ0v7K3Cuy7iuezi+zng5kYLFXuv0o= Date: Sat, 25 Apr 2020 20:53:13 +0200 From: Borislav Petkov To: Segher Boessenkool Cc: Arvind Sankar , Jakub Jelinek , jgross@suse.com, x86@kernel.org, Kees Cook , Peter Zijlstra , linuxppc-dev@lists.ozlabs.org, Michael Matz , Nick Desaulniers , LKML , Sergei Trofimovich , clang-built-linux , Ingo Molnar , Paul Mackerras , Andy Lutomirski , "H. Peter Anvin" , =?utf-8?Q?Fr=C3=A9d=C3=A9ric_Pierret_=28fepitre=29?= , Thomas Gleixner , Martin =?utf-8?B?TGnFoWth?= , boris.ostrovsky@oracle.com Subject: Re: [PATCH] x86: Fix early boot crash on gcc-10, next try Message-ID: <20200425185313.GD24294@zn.tnic> References: <20200422212605.GI26846@zn.tnic> <20200423125300.GC26021@zn.tnic> <20200423161126.GD26021@zn.tnic> <20200425014657.GA2191784@rani.riverdale.lan> <20200425085759.GA24294@zn.tnic> <20200425150440.GA470719@rani.riverdale.lan> <20200425173140.GB24294@zn.tnic> <20200425183701.GE17645@gate.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200425183701.GE17645@gate.crashing.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 25, 2020 at 01:37:01PM -0500, Segher Boessenkool wrote: > That is a lot more typing then > asm(""); That's why a macro with a hopefully more descriptive name would be telling more than a mere asm(""). > but more seriously, you probably should explain why you do not want a > tail call *anyway*, and in such a comment you can say that is what the > asm is for. Yes, the final version will have a comment and the whole spiel. This diff is just me polling the maintainers: "do you want this for your arch too?" Well, the PPC maintainers only, actually. The other call in init/main.c would be for everybody. > I don't see anything that prevents the tailcall in current code either, > fwiw. Right, and I don't see a reason why gcc-10 would do that optimization on x86 only but I better ask first. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette 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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 F00FEC54FCB for ; Sat, 25 Apr 2020 18:55:04 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 510CA2072B for ; Sat, 25 Apr 2020 18:55:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="J1HDIxyv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 510CA2072B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 498gFx4Qg4zDqTG for ; Sun, 26 Apr 2020 04:55:01 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=alien8.de (client-ip=5.9.137.197; helo=mail.skyhub.de; envelope-from=bp@alien8.de; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=alien8.de header.i=@alien8.de header.a=rsa-sha256 header.s=dkim header.b=J1HDIxyv; dkim-atps=neutral X-Greylist: delayed 4885 seconds by postgrey-1.36 at bilbo; Sun, 26 Apr 2020 04:53:24 AEST Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 498gD46n8CzDqRY for ; Sun, 26 Apr 2020 04:53:23 +1000 (AEST) Received: from zn.tnic (p200300EC2F2A1100B46A3E12B0A6AFFD.dip0.t-ipconnect.de [IPv6:2003:ec:2f2a:1100:b46a:3e12:b0a6:affd]) (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 8527F1EC0C84; Sat, 25 Apr 2020 20:53:20 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1587840800; 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=iTbPHyhUCYp1hsTKDTL6Rkak9xj3g4rssRfqZNkVLdA=; b=J1HDIxyv/9Q6KrgTFyzUaS9MzUgSTqUl1CHKzxt9TsfuRWCgenOsqkBAUiSvooHmIFgoYR xTFg4Y4kCmZjWDIrRtDZdBKr0CU76/YyCxbHLM8CBk0vP11S/rVp9yFpSmoUqaXMTtJMbC uoQ0v7K3Cuy7iuezi+zng5kYLFXuv0o= Date: Sat, 25 Apr 2020 20:53:13 +0200 From: Borislav Petkov To: Segher Boessenkool Subject: Re: [PATCH] x86: Fix early boot crash on gcc-10, next try Message-ID: <20200425185313.GD24294@zn.tnic> References: <20200422212605.GI26846@zn.tnic> <20200423125300.GC26021@zn.tnic> <20200423161126.GD26021@zn.tnic> <20200425014657.GA2191784@rani.riverdale.lan> <20200425085759.GA24294@zn.tnic> <20200425150440.GA470719@rani.riverdale.lan> <20200425173140.GB24294@zn.tnic> <20200425183701.GE17645@gate.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200425183701.GE17645@gate.crashing.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jakub Jelinek , jgross@suse.com, Michael Matz , Kees Cook , Peter Zijlstra , Martin =?utf-8?B?TGnFoWth?= , x86@kernel.org, Nick Desaulniers , LKML , Sergei Trofimovich , clang-built-linux , Arvind Sankar , Ingo Molnar , Paul Mackerras , Andy Lutomirski , "H. Peter Anvin" , =?utf-8?Q?Fr=C3=A9d=C3=A9ric_Pierret_=28fepitre=29?= , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, boris.ostrovsky@oracle.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, Apr 25, 2020 at 01:37:01PM -0500, Segher Boessenkool wrote: > That is a lot more typing then > asm(""); That's why a macro with a hopefully more descriptive name would be telling more than a mere asm(""). > but more seriously, you probably should explain why you do not want a > tail call *anyway*, and in such a comment you can say that is what the > asm is for. Yes, the final version will have a comment and the whole spiel. This diff is just me polling the maintainers: "do you want this for your arch too?" Well, the PPC maintainers only, actually. The other call in init/main.c would be for everybody. > I don't see anything that prevents the tailcall in current code either, > fwiw. Right, and I don't see a reason why gcc-10 would do that optimization on x86 only but I better ask first. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette