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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_MUTT 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 CEB38C28CC3 for ; Fri, 7 Jun 2019 09:39:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 A451A20684 for ; Fri, 7 Jun 2019 09:39:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="dYN0gJGK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A451A20684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=3d64eUwoIjAIcSH5AcK/vaegWjTHMuC2FD2B95ZdSvs=; b=dYN0gJGK1X2FaH /fZMXdzhQjmyqdOdXWjUINH6QLJpfysks5RR0U8IM/d7dFJV3JZP1MxKNq2OwKMVBZrcvjGrXvLLj U3gWjvTPMDMbAk3LmVd3gpuY4rfgTlhGDia/fedOzLMEZ1cX0Spkpm2fpaUzPNWUv6fPVchF4w+zf HGRAfCN8uLC+4GCcmWtVy7Vxm8RqHoIOvCmlxpcwS6r5gHmGx94JOOCZB2mApT0cy7cwKIwrp+2AC ASHt6Hlx2ShrWpxzSOordUtmHkFguo5a8d+zN80wDamM1OZVlH1kgJOTStS5f5KrfiLcTlSUk2Z/S 9witkt4xc7FFbDsGFyTg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hZBL2-000102-70; Fri, 07 Jun 2019 09:39:08 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hZBL0-0000zV-2m for linux-arm-kernel@lists.infradead.org; Fri, 07 Jun 2019 09:39:07 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E4EFB360; Fri, 7 Jun 2019 02:39:03 -0700 (PDT) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C50F93F96A; Fri, 7 Jun 2019 02:39:02 -0700 (PDT) Date: Fri, 7 Jun 2019 10:38:58 +0100 From: Will Deacon To: Dave Martin Subject: Re: [PATCH 0/2] arm64/sve: Fix mutating register endianness on big-endian Message-ID: <20190607093858.GA21378@fuggles.cambridge.arm.com> References: <1559839495-22315-1-git-send-email-Dave.Martin@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1559839495-22315-1-git-send-email-Dave.Martin@arm.com> User-Agent: Mutt/1.11.1+86 (6f28e57d73f2) () X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190607_023906_171754_E6A26469 X-CRM114-Status: GOOD ( 14.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , gdb@sourceware.org, Zhang Lei , Julien Grall , Catalin Marinas , Alex =?iso-8859-1?Q?Benn=E9e?= , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jun 06, 2019 at 05:44:53PM +0100, Dave Martin wrote: > By inspection while debugging something else, I noticed that the byte > order of FPSIMD V-register stores and SVE Z-register stores is not the > same when running on big-endian. > > This is not properly taken into account when moving between the FPSIMD > and SVE register views inside the kernel, resulting in the bytes of a > V-register getting spontaneously reversed in some situations, from > userspace's point of view. The signal frame and ptrace interface are > also affected. The KVM ABI forbids mixing the two views and so should > not be affected. > > See patch 2 for details. > > Patch 1 does some trivial preparatory refactoring. Sorry to be a pain, but would you be able to flip this series round so that the fix doesn't depend on the refactoring, please? That way we can put it into stable without the dependency. > gdb may or may not be affected by this, depending on how it uses the > NT_PRFPREG and NT_ARM_SVE regsets. I'll leave it to the developers to > assess that. Wouldn't this be easy enough to test? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel