Received: by 2002:a05:6a10:206:0:0:0:0 with SMTP id 6csp1221307pxj; Fri, 4 Jun 2021 08:56:25 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwISDvyj04o3AnUDDjYOxThE+9hCh/4/7aaJfkIDs1f1LXyfQiaVT+LAEIifpo5t95fiOnX X-Received: by 2002:a50:8dc6:: with SMTP id s6mr5485231edh.50.1622822185010; Fri, 04 Jun 2021 08:56:25 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1622822185; cv=none; d=google.com; s=arc-20160816; b=HfHUvLULuxvWpij1N0Y4D9xzLDsy2uN7JvzaugqcEo0nYJ20FyJRgY/gbT1qFRVyJM xJqDrdakYB7lOyI6kG+QDw0OTxqGaY/fm2Wv2Ls+uLXRFfjuqyX8KAUWhhFGVBp9BVEE EbLStoQT/GaUtIP5JyTrVZ1vRtedlp4t0S40s+zLrnu8kLhKB/r2CgS98AFR1bwiOUMb aJUM/VbFVtNQ7sStFnc7xXOJX5MGRDkHe79UcfEqRM+gWxJaSO6pnUL4ojbzG1tP2DBd wEaTcW7Qnq2Jd5UOWJJI1zMWDMFtpDKOnbUYIP/djQAJKmx6s5ffgbIUCEkYsPoyS0LV EbqA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:user-agent:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date; bh=3nbgTf+n2e3LxlPn9/aEYsTo2BL651S2gcGxsjoMltc=; b=GVYKRqMxwSy83ZDMEx/rGypxEDk5C9fNItIFxklWDSt8ZKPpepe3IeNGXxSdSbI+Jn H2d8ldZBY64UFqkrDe1A7657HB5wZRHuQQCOe9nvMVFJbBVH20E1zoWYir2JmZaWReTt nV72Zwt6yxGUmhzlSoA1Q0fZjy73A1mfpI79dN2gnupj8k0ktbzEzWFI6Vn4vKQvUF/3 CUdC0g3S9jUf57Woavwdc/BeTYlSAm0BbNwvOkAwZKQ01RjGtnOUJJSZGhE3TEX+RYoP db5r+8RjxdqexkHjgAWr5PPinpGjcXgXnaRBYlXs5hfBpbHpAoKMM8Fa+pna/hrvKGBa F2XQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id j16si6325494edj.401.2021.06.04.08.56.01; Fri, 04 Jun 2021 08:56:25 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231213AbhFDP4c (ORCPT + 99 others); Fri, 4 Jun 2021 11:56:32 -0400 Received: from gate.crashing.org ([63.228.1.57]:35782 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229809AbhFDP4b (ORCPT ); Fri, 4 Jun 2021 11:56:31 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 154FoTb5021396; Fri, 4 Jun 2021 10:50:29 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 154FoSDI021394; Fri, 4 Jun 2021 10:50:28 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 4 Jun 2021 10:50:28 -0500 From: Segher Boessenkool To: Peter Zijlstra Cc: Will Deacon , Linus Torvalds , paulmck@kernel.org, stern@rowland.harvard.edu, parri.andrea@gmail.com, boqun.feng@gmail.com, npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk, luc.maranget@inria.fr, akiyks@gmail.com, linux-kernel@vger.kernel.org, linux-toolchains@vger.kernel.org, linux-arch@vger.kernel.org Subject: Re: [RFC] LKMM: Add volatile_if() Message-ID: <20210604155028.GF18427@gate.crashing.org> References: <20210604104359.GE2318@willie-the-truck> <20210604134422.GA2793@willie-the-truck> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 04, 2021 at 03:56:16PM +0200, Peter Zijlstra wrote: > Urgh, I see. Compiler can't really help in that case either I'm afraid. > They'll never want to modify loads that originate in an asm(). We never *can* change an asm template. That is part of the fundamental properties of inline asm. We cannot even parse it! Segher