From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f68.google.com (mail-wm1-f68.google.com [209.85.128.68]) by mx.groups.io with SMTP id smtpd.web10.12314.1590152516644275650 for ; Fri, 22 May 2020 06:01:56 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@nuviainc-com.20150623.gappssmtp.com header.s=20150623 header.b=DE/wnbQ/; spf=pass (domain: nuviainc.com, ip: 209.85.128.68, mailfrom: leif@nuviainc.com) Received: by mail-wm1-f68.google.com with SMTP id u12so4940830wmd.3 for ; Fri, 22 May 2020 06:01:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nuviainc-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=gsvt7WTEnVCA8YPEu675sRpaKVmDAyCdgyFpXrNVKag=; b=DE/wnbQ/OPWysarIUDMLTPt79KdcjTCM792va6hunX0MIlJcBWhZT69YxETuO4AJWn Q2pKRwLBOdUSH1sQil2ZZgE5OIBqtpurpnLr1uHYcI8VTZ6DNn5j6oR8qaoPktHmTnLq 9PozRvY9XoIrca5/OgrUvj0DCCD4H+AWFSMS2VpK8dnK0ObIHyU0BpBJ7UBENxf4Mb1Y JFeVY569gVTj4QqZ0kr4bSfFkRaA5otl5TcV/etqEbMyIo50jpjkcU3gseJFknijCjXJ 17/SQLrjY9jilLncn5PfiOEk7Stj+wWV17ObDmocXw+4p/QfaXboUlZWN0sMzcpPTj2m 5FzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=gsvt7WTEnVCA8YPEu675sRpaKVmDAyCdgyFpXrNVKag=; b=rDNOOTqRrFboQkrAF6e99pkH3yNbl/6DyNUH5DlXbuKaa5ZbG08Kvb5xPxXtzcUVD6 j5k278v0zPZEfLLYHxBBaVCwklNLHOdn7sDw5fLZGWSyjd2uUGqupc97pyncCuHdD9/z x/okmPQh5CREVTmuvCoDPNT9DTxvdT/v7Hemo8EFKsSSviFJgQyTZyBKw0uvsMVuLQYN ae73d52LKSOyt+B/XjUi9u3SqaUkYFfRmh+OEL6m0dXBGPL4qqE0/LXy2OonufZvZq7u 7GiVFNIhm9W3B5Tsz9ptbtPod5sleOL4L0z1QCKdoLcovyBvvRZK5lEK7EIziePo1eKj nknQ== X-Gm-Message-State: AOAM531hz50h58gjQ8trmHwTqQy/FsWf79DnG1dCKM4j49fZqrFhPPfv KyygOtiCl55sYfv60k0YZ0bYyQ== X-Google-Smtp-Source: ABdhPJywinZhurAxfhR+4tiNtRlALZ3rEE9Mkud/JJQMILbDfqZH55PCXpWNuUbC8uKjEW4M9fbVgw== X-Received: by 2002:a7b:cbd4:: with SMTP id n20mr13256640wmi.101.1590152514818; Fri, 22 May 2020 06:01:54 -0700 (PDT) Return-Path: Received: from vanye ([2001:470:1f09:12f0:b26e:bfff:fea9:f1b8]) by smtp.gmail.com with ESMTPSA id i21sm9510296wml.5.2020.05.22.06.01.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 May 2020 06:01:54 -0700 (PDT) Date: Fri, 22 May 2020 14:01:52 +0100 From: "Leif Lindholm" To: Ard Biesheuvel Cc: devel@edk2.groups.io, liming.gao@intel.com, lersek@redhat.com, philmd@redhat.com, mliska@suse.cz Subject: Re: [PATCH] MdePkg/Include: AARCH64: disable outline atomics on GCC 10.2+ Message-ID: <20200522130152.GE1923@vanye> References: <20200522101202.15016-1-ard.biesheuvel@arm.com> <20200522114101.GA1923@vanye> <628c2f09-207c-3146-df98-30ee2426899b@arm.com> <20200522121413.GC1923@vanye> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, May 22, 2020 at 14:42:34 +0200, Ard Biesheuvel wrote: > > > > > --- > > > > > The GCC support for this pragma has already been pulled into the 10.2 > > > > > release branch. I think we should consider adding this to the stable > > > > > tag, so that the issue can easily be resolved by upgrading the compiler. > > > > > Whether we add the intrinsics too is a separate matter, but we can > > > > > revisit that later. > > > > > > > > Hmm. I am just slightly concerned over referencing GCC 10.2 before GCC > > > > 10.2 is released. > > > > Presumably, there will be no ill effects if that pragma is enabled also > > > > on 10.2, we just won't need it? If so ... > > > > > > > > > > No the pragma is only enabled on 10.2 and later. Older GCCs will choke on > > > it. > > > > Urgh, right. I guess I'm having a "can't read" day. > > > > Still. That means that if the pragma gets pulled last second from > > 10.2, we now explicitly break builds for 10.2. > > No matter how low the risk of that happening, this doesn't make me > > comfortable. > > Indeed. So assuming that we won't take the atomics patch for the stable tag, > we already know it will be broken for all GCC 10 and up. Which isn't ideal, as we're seeing people picking that up. I think in a list of not great options I would probably prefer getting the intrinsics into the stable tag. / Leif