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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,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 9A4D7C43331 for ; Sun, 29 Mar 2020 18:55:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B5452073E for ; Sun, 29 Mar 2020 18:55:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585508156; bh=EFZ2OeztVzimjd6pSDwTHlw3oKYDIp8szAopyzNKBIw=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=a34JuyPthZtvAVb4evxvN73aTO5UB2xsbqyIe5jGwjmyajCexAEC7twjri/L7vVW+ qurbQuKl8dpf83Rw6+z9fJAklLWmN0wLp6Iy7AIPJ/DoqYmp8RWJneBvfttcnkJaqI faXZDYqSlkqO9M2ZwKtn5HVYZr9Bh159fNuCPMfA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728538AbgC2Szz (ORCPT ); Sun, 29 Mar 2020 14:55:55 -0400 Received: from mail-lf1-f68.google.com ([209.85.167.68]:35107 "EHLO mail-lf1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726283AbgC2Szz (ORCPT ); Sun, 29 Mar 2020 14:55:55 -0400 Received: by mail-lf1-f68.google.com with SMTP id t16so11361331lfl.2 for ; Sun, 29 Mar 2020 11:55:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=UzKIqjkzj7/Eq13gEM5B5ww/GQ27+9p2+1RGc78xjeY=; b=D+OjUPi3ac95W7wx3JJ+HoZ9kpnqs7I9BWSpuiS7wpheI0dITNUhYwkvqOqLLBNYDh 9WAbxP7m6Sa5QIhVj9VyhWYDMUKkVVEAbxSY/yCNmYwu25Zcr07r7yvq0asr3LG9inQo L7vDJ8tlVdyT5LHFiQVKewJYbq9Vs/tl4Vw6A= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=UzKIqjkzj7/Eq13gEM5B5ww/GQ27+9p2+1RGc78xjeY=; b=Z1VnqbQHuedhstImUk6zEOmS7JbFxMclBxCwUFkOpfaZLO5mPhd4e2NyynEqysv3sF cxu6JhGme9cyw3pRZ+Z2e2YnkSUOQMAMheKdmgnhLf7MWOAJzkCQ28VT7pACd7mU4RsX 28GGZa77kht222K0/BAwqHtQp7tcMsyVNp7XTNHT+EX068Qjk7AvMOLtZQifwsweW41w +tjFYOW9iBAwqsuPH5BKp1Ts5i12dyXVrdVONoW+WM+qwaeNefgCFRrcS1QnsmdmqhnC qj1StQyfIK44UDkFUcB1mEZERBUycD8jbPSC2TsEFjriTJISeZc/XZ6GHoUjHg2Omf/c vSYQ== X-Gm-Message-State: AGi0Pua41w0UiJcWy+qIkivRGBweLyDNA9F8Blwo18KrA+3YsTOvZgSy E9dUPnvEzl7hwTQKL02NaTOItC0ugFI= X-Google-Smtp-Source: APiQypILsiLFycq+aESlfD5B3rkog8Ez8JD0Z7YN+JxXyQ36EB2fvwzPMenYIfHrjxRCf1giehSf5Q== X-Received: by 2002:a19:c388:: with SMTP id t130mr5980962lff.175.1585508150955; Sun, 29 Mar 2020 11:55:50 -0700 (PDT) Received: from mail-lf1-f53.google.com (mail-lf1-f53.google.com. [209.85.167.53]) by smtp.gmail.com with ESMTPSA id e4sm777246lfn.80.2020.03.29.11.55.49 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 29 Mar 2020 11:55:50 -0700 (PDT) Received: by mail-lf1-f53.google.com with SMTP id v4so12150000lfo.12 for ; Sun, 29 Mar 2020 11:55:49 -0700 (PDT) X-Received: by 2002:ac2:5e36:: with SMTP id o22mr5576296lfg.142.1585508149219; Sun, 29 Mar 2020 11:55:49 -0700 (PDT) MIME-Version: 1.0 References: <20200323183620.GD23230@ZenIV.linux.org.uk> <20200323183819.250124-1-viro@ZenIV.linux.org.uk> <20200328104857.GA93574@gmail.com> <20200328115936.GA23230@ZenIV.linux.org.uk> <20200329092602.GB93574@gmail.com> <489c9af889954649b3453e350bab6464@AcuMS.aculab.com> <9352bc55302d4589aaf2461c7b85fb6b@AcuMS.aculab.com> In-Reply-To: From: Linus Torvalds Date: Sun, 29 Mar 2020 11:55:33 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC][PATCH 01/22] x86 user stack frame reads: switch to explicit __get_user() To: David Laight Cc: Andy Lutomirski , Ingo Molnar , Al Viro , Thomas Gleixner , X86 ML , LKML , Borislav Petkov Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 29, 2020 at 11:32 AM David Laight wrote: > > Can't you simplify that by using the =d constraint rather > than relying on a asm register variable. No, because that asm register variable can be 64-bit. Which on x86-32 isn't "=d". It's "%edx:%ecx". The asm register variable thing handles that automatically, but "=d" would not. Linus