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=0.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,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 EA85CC48BE0 for ; Fri, 11 Jun 2021 10:42:05 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 97DD5613AE for ; Fri, 11 Jun 2021 10:42:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 97DD5613AE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.140345.259340 (Exim 4.92) (envelope-from ) id 1lrebh-0004KC-Mi; Fri, 11 Jun 2021 10:41:45 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 140345.259340; Fri, 11 Jun 2021 10:41:45 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lrebh-0004K5-JJ; Fri, 11 Jun 2021 10:41:45 +0000 Received: by outflank-mailman (input) for mailman id 140345; Fri, 11 Jun 2021 10:41:44 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lrebg-0004Jz-Bq for xen-devel@lists.xenproject.org; Fri, 11 Jun 2021 10:41:44 +0000 Received: from mail-oo1-xc2f.google.com (unknown [2607:f8b0:4864:20::c2f]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 4aea13a4-3130-4dc0-8790-2cb94719df8f; Fri, 11 Jun 2021 10:41:43 +0000 (UTC) Received: by mail-oo1-xc2f.google.com with SMTP id o5-20020a4a2c050000b0290245d6c7b555so595989ooo.11 for ; Fri, 11 Jun 2021 03:41:43 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 4aea13a4-3130-4dc0-8790-2cb94719df8f DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dzmI3mcjI9bUqS7jOZe2FaB9jsbtLcrJ9WxglaseTWk=; b=NJCDqOtUSiKC9vHEGGAOmo2nBCb8xe3OL4alTUH6l0IgYKHJq8007qP5L6PP4fjHXN eAfjz3EgRXIzRScTtwAjUpkGs6N4tDoOFbCk4TBjrL0WAm+ooeNDyO6R9NXyARTH2Esj 7PVG2wpHi0JV/b64Um4sxtFNROymjgbcNlk8uZmUfVMlg3mwfQmMpkxLmRm5bqANyuOS 1QF/AEimMIzSNJsb3KCGUZqlVafWkxY6jDb0NsV3lxNWRfQYgYQ99h/rcHvLgUbVkb+n 9oMnut0KgtyQ5exZisrICJhHgxilJnJS9Rb06/eSENSDz1E9EU19rGx334MHBgK/bi5I 4KYQ== 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=dzmI3mcjI9bUqS7jOZe2FaB9jsbtLcrJ9WxglaseTWk=; b=gV+qLQB+amDv63eyzmTcUdobp5m29BwLNAYK8pz6k8ZmQCsVBhpmSe4rVUSaP/waBx 6hqf9I+2X7O0iZCjkyKkiHN8Lqn81C9ck2w9hE+QjiVkrP8N+2wI/vuFGLzhS9EKHBh/ KJXhs3n6KB6/wP+pDV3O8QCizUF6zl3+glYPFocF4bbWzSw6fwqKR/6KUZ04FLq0qTNt m+aq73Jg9g4h1Q5MBVyNEgkwo+jYFFVP1l0l25n4bcmMQmBMB59ZLwWBPDuwFYl2RdgL CgIfR/eJIbmwzRQuS3UdTK7/0ifbnim6Czr3SIY4AMYAPHU48NK0nwB4UkaXqQe9jz2q YPeA== X-Gm-Message-State: AOAM533QV9l7hd8mHRbNee1C73LosqLcMwiJTRchRzBc5zv0wZqDu//P L4Iwu+WslsihKntR+DqPBxhpa4/M2p3ReJ1d2hM= X-Google-Smtp-Source: ABdhPJzHaE/hJ3Ygoh19x0vqZOz7BX5zgJi5Ecf1EryaUuWy8ZhEPPlEb07Xp9lVtjnymSgrDG/1sLz2PpYetvX+qns= X-Received: by 2002:a4a:625a:: with SMTP id y26mr2511543oog.38.1623408102677; Fri, 11 Jun 2021 03:41:42 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Julien Grall Date: Fri, 11 Jun 2021 11:41:30 +0100 Message-ID: Subject: Re: [PATCH] Arm32: MSR to SPSR needs qualification To: Jan Beulich Cc: Julien Grall , xen-devel , Stefano Stabellini Content-Type: multipart/alternative; boundary="00000000000049206905c47b2798" --00000000000049206905c47b2798 Content-Type: text/plain; charset="UTF-8" On Fri, 11 Jun 2021, 11:16 Jan Beulich, wrote: > On 11.06.2021 10:00, Julien Grall wrote: > > On Fri, 11 Jun 2021, 08:55 Jan Beulich, wrote: > > > >> The Arm ARM's description of MSR doesn't even allow for plain "SPSR" > >> here, and while gas accepts this, it takes it to mean SPSR_cf. Yet > >> surely all of SPSR wants updating on this path, not just the lowest and > >> highest 8 bits. > >> > > > > Can you provide a reference to the Arm Arm? This would help to navigate > > through the 8000 pages. > > Referencing the instruction page would be enough, I thought (as > even I, not being an Arm person, have no difficulty locating it). > If it isn't, how is a canonical doc ref supposed to look like on > Arm? On x86, we avoid recording document versions, section > numbers, or even page numbers in code comments or commit messages > (which isn't to say we have none of these, but we try to avoid > new ones to appear), as these tend to change with every new > version of the doc. Therefore, to me, the offending commit's "ARM > DDI 0487D.b page G8-5993" doesn't look like something I wanted to > clone from. But if you tell me otherwise, then well - so be it. The Arm website provides a link for nearly every revision on the specs. As the wording can change between version, it is useful to know which spec the understanding is based from. Note that for Arm32 we should quote the Armv7 spec and not the Armv8 one because we only follow the former (there are a few small differences). > Jan > > > --00000000000049206905c47b2798 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Fri, 11 Jun 2021, 11:16 Jan Beulich, <jbeulich@suse.com> wrote:
On 11.06.2021 10:00, Julien Grall wrote:
> On Fri, 11 Jun 2021, 08:55 Jan Beulich, <jbeulich@suse.com> w= rote:
>
>> The Arm ARM's description of MSR doesn't even allow for pl= ain "SPSR"
>> here, and while gas accepts this, it takes it to mean SPSR_cf. Yet=
>> surely all of SPSR wants updating on this path, not just the lowes= t and
>> highest 8 bits.
>>
>
> Can you provide a reference to the Arm Arm? This would help to navigat= e
> through the 8000 pages.

Referencing the instruction page would be enough, I thought (as
even I, not being an Arm person, have no difficulty locating it).
If it isn't, how is a canonical doc ref supposed to look like on
Arm? On x86, we avoid recording document versions, section
numbers, or even page numbers in code comments or commit messages
(which isn't to say we have none of these, but we try to avoid
new ones to appear), as these tend to change with every new
version of the doc. Therefore, to me, the offending commit's "ARM<= br> DDI 0487D.b page G8-5993" doesn't look like something I wanted to<= br> clone from. But if you tell me otherwise, then well - so be it.

The Arm website provides a link for nearly every revision on the = specs. As the wording can change between version, it is useful to know whic= h spec the understanding is based from.

=C2=A0Note that for Arm32 we should quote the Armv7 spec an= d not the Armv8 one because we only follow the former (there are a few smal= l differences).



Jan


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