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 3EBF0C433ED for ; Mon, 12 Apr 2021 14:31:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 117E26128E for ; Mon, 12 Apr 2021 14:31:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242250AbhDLOcD (ORCPT ); Mon, 12 Apr 2021 10:32:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237806AbhDLOcB (ORCPT ); Mon, 12 Apr 2021 10:32:01 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FC96C061574; Mon, 12 Apr 2021 07:31:43 -0700 (PDT) Received: from zn.tnic (p200300ec2f052100b992cfc3eab27929.dip0.t-ipconnect.de [IPv6:2003:ec:2f05:2100:b992:cfc3:eab2:7929]) (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 859EB1EC03A0; Mon, 12 Apr 2021 16:31:41 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1618237901; 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=Drxp9AwmCgzA/Iszpvwrzfn9ABJRPDxoumDeD2kDwN0=; b=Q7DrDWatKFZgNJBHP4Qx/QznmbVTPC09Oxn/rLikYikgm5ESUgyZ9nv+jmO5tKlGpYu9Ba 4BNTO9HquC5hp9c/AbTXnzd3Bz1o/F5bTf828MHOEK9nZD2LXxQIQ+UieBuwn0pk4GBZep j/3SmxTJ6kkkyWwd8fdnJ40mROyoVuk= Date: Mon, 12 Apr 2021 16:31:39 +0200 From: Borislav Petkov To: Florian Weimer Cc: Andy Lutomirski , "Bae, Chang Seok" , Dave Hansen , X86 ML , LKML , linux-abi@vger.kernel.org, "libc-alpha@sourceware.org" , Rich Felker , Kyle Huey , Keno Fischer Subject: Re: Candidate Linux ABI for Intel AMX and hypothetical new related features Message-ID: <20210412143139.GE24283@zn.tnic> References: <87lf9nk2ku.fsf@oldenburg.str.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87lf9nk2ku.fsf@oldenburg.str.redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 12, 2021 at 04:19:29PM +0200, Florian Weimer wrote: > Maybe we could have done this in 2016 when I reported this for the first > time. Now it is too late, as more and more software is using > CPUID-based detection for AVX-512. So as I said on another mail today, I don't think a library should rely solely on CPUID-based detection of features especially if those features need kernel support too. IOW, it should ask whether the kernel can handle those too, first. And the CPUID-faulting thing would solve stuff like that because then the kernel can *actually* get involved into answering something where it has a say in, too. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette