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=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 5769BC43603 for ; Wed, 18 Dec 2019 11:48:40 +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 227DA21582 for ; Wed, 18 Dec 2019 11:48:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="f7Xq50bx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 227DA21582 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53014 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ihXol-0004ss-BI for qemu-devel@archiver.kernel.org; Wed, 18 Dec 2019 06:48:39 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:39817) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ihXnr-00046m-Ce for qemu-devel@nongnu.org; Wed, 18 Dec 2019 06:47:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ihXno-000871-JH for qemu-devel@nongnu.org; Wed, 18 Dec 2019 06:47:41 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:32243 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ihXno-00082l-Dg for qemu-devel@nongnu.org; Wed, 18 Dec 2019 06:47:40 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576669659; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JkKzgVFviV1oz05kvLpRwSq9YD/v5ZWhz3u6FbmBZew=; b=f7Xq50bxwfP7qKA965LfDuXYVFc3xzjPrnGjIRK1f1zfGtNkESVyZh1pLV5nn+ZJ/QSp0J HVdVYba0w+C+ZPmtHA5qlywTncDQJNoC9V/MX18codjRLgNjO+H3ax/ba6p5oGbzanbWZz H3rWu/7M/ViDdAzohmVNzGqGZG7P1Qc= 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-360-Ck1lbBNSMfqfU1-LRK45iA-1; Wed, 18 Dec 2019 06:47:36 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7AF8E800D48; Wed, 18 Dec 2019 11:47:35 +0000 (UTC) Received: from gondolin (ovpn-117-253.ams2.redhat.com [10.36.117.253]) by smtp.corp.redhat.com (Postfix) with ESMTP id 719666888A; Wed, 18 Dec 2019 11:47:34 +0000 (UTC) Date: Wed, 18 Dec 2019 12:47:31 +0100 From: Cornelia Huck To: Thomas Huth Subject: Re: [PATCH] tests/boot-sector: Fix the bad s390x assembler code Message-ID: <20191218124731.24799ddf.cohuck@redhat.com> In-Reply-To: <20191217150642.27946-1-thuth@redhat.com> References: <20191217150642.27946-1-thuth@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: Ck1lbBNSMfqfU1-LRK45iA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 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: qemu-s390x@nongnu.org, qemu-devel@nongnu.org, Janosch Frank Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 17 Dec 2019 16:06:42 +0100 Thomas Huth wrote: > There are currently two bugs in s390x_code[]: First, the initial jump > uses the wrong offset, so it was jumping to 0x1014 instead of 0x1010. > Second, LHI only loads the lower 32-bit of the register. > > Everything worked fine as long as the s390-ccw bios code was jumping > here with r3 containing zeroes in the uppermost 48 bit - which just > happened to be the case so far by accident. But we can not rely on this > fact, and indeed one of the recent suggested patches to jump2ipl.c cause > the newer GCCs to put different values into r3. In that case the code > from s390x_code[] crashes very ungracefully. > > Thus let's make sure to jump to the right instruction, and use LGHI > instead of LHI to make sure that we always zero out the upper bits > of the register. > > Signed-off-by: Thomas Huth > --- > tests/boot-sector.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tests/boot-sector.c b/tests/boot-sector.c > index 7824286b9a..9e66c6d013 100644 > --- a/tests/boot-sector.c > +++ b/tests/boot-sector.c > @@ -75,11 +75,11 @@ static const uint8_t s390x_psw_and_magic[] = { > 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40 /* in the s390-ccw bios */ > }; > static const uint8_t s390x_code[] = { > - 0xa7, 0xf4, 0x00, 0x0a, /* j 0x10010 */ > + 0xa7, 0xf4, 0x00, 0x08, /* j 0x10010 */ > 0x00, 0x00, 0x00, 0x00, > 'S', '3', '9', '0', > 'E', 'P', 0x00, 0x01, > - 0xa7, 0x38, HIGH(SIGNATURE_ADDR), LOW(SIGNATURE_ADDR), /* lhi r3,0x7c10 */ > + 0xa7, 0x39, HIGH(SIGNATURE_ADDR), LOW(SIGNATURE_ADDR), /* lghi r3,0x7c10 */ > 0xa7, 0x48, LOW(SIGNATURE), HIGH(SIGNATURE), /* lhi r4,0xadde */ > 0x40, 0x40, 0x30, 0x00, /* sth r4,0(r3) */ > 0xa7, 0xf4, 0xff, 0xfa /* j 0x10010 */ Looks good to me. I plan to queue this (and re-queue the other patches I had dropped), but would not mind another review.