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=-10.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 8E66CC4332F for ; Mon, 13 Sep 2021 08:11:35 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 3038360D42 for ; Mon, 13 Sep 2021 08:11:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3038360D42 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:44544 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mPh3u-0001sy-6k for qemu-devel@archiver.kernel.org; Mon, 13 Sep 2021 04:11:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50662) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mPh0F-0006qO-Dp for qemu-devel@nongnu.org; Mon, 13 Sep 2021 04:07:47 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:53931) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mPh0C-0003gL-Ns for qemu-devel@nongnu.org; Mon, 13 Sep 2021 04:07:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631520462; 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: in-reply-to:in-reply-to:references:references; bh=7MYKYU6cb3Ucab7ZbAB7f6G2EaWRAq5LuR2qkEqDaNs=; b=F7csKTvng/nbhfrt3DNk2hTloKF1GLOIbB1qAOT2n216Wdj4XMed7PgdC4OfnzAvtGnAwe Mez2YoKBwBSdbprF0ZrFMe5bj+xTTWr9D8WU8KdZ/k7aDkWkMo+nwnG9jY7emhTfHfXJ3d L2hH6z5Q5rPdQar4GEr8/9aGo2OtBhg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-580-6BBnIG8yPjWXh1W7yWAZpQ-1; Mon, 13 Sep 2021 04:07:40 -0400 X-MC-Unique: 6BBnIG8yPjWXh1W7yWAZpQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CC87B1006AA1; Mon, 13 Sep 2021 08:07:39 +0000 (UTC) Received: from localhost (unknown [10.39.192.185]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7AA8619724; Mon, 13 Sep 2021 08:07:39 +0000 (UTC) Date: Mon, 13 Sep 2021 09:07:38 +0100 From: "Richard W.M. Jones" To: Richard Henderson Subject: Re: [PATCH] tcg/arm: Reduce vector alignment requirement for NEON Message-ID: <20210913080738.GC26415@redhat.com> References: <20210912174925.200132-1-richard.henderson@linaro.org> MIME-Version: 1.0 In-Reply-To: <20210912174925.200132-1-richard.henderson@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=rjones@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=rjones@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.393, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sun, Sep 12, 2021 at 10:49:25AM -0700, Richard Henderson wrote: > With arm32, the ABI gives us 8-byte alignment for the stack. > While it's possible to realign the stack to provide 16-byte alignment, > it's far easier to simply not encode 16-byte alignment in the > VLD1 and VST1 instructions that we emit. > > Remove the assertion in temp_allocate_frame, limit natural alignment > to the provided stack alignment, and add a comment. > > Reported-by: Richard W.M. Jones > Signed-off-by: Richard Henderson > --- > > I haven't seen the assertion with the various arm kernels that I happen > to have laying about. I have not taken the time to build the combo > from the bug report: > > [ 0.000000] Linux version 5.14.0-60.fc36.armv7hl (mockbuild@buildvm-a32-12.iad2.fedoraproject.org) (gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-1), GNU ld version 2.37-9.fc36) #1 SMP Mon Aug 30 14:08:34 UTC 2021 > > I thought about parameterizing this patch further, but I can't think of > another ISA that would be affected. (i686 clumsily changed its abi 20 > years ago to avoid faulting on vector spills; other isas so far have > allowed vectors to be unaligned.) You should be able to download the Fedora kernel that I am using from https://koji.fedoraproject.org/koji/packageinfo?packageID=8 I added the patch to Fedora qemu and will do a test build once it becomes available to build against - currently there's some problem with new builds not propagating to the new buildroot. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW