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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,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 A2C51C6778A for ; Mon, 9 Jul 2018 10:40:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A98820862 for ; Mon, 9 Jul 2018 10:40:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A98820862 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-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754527AbeGIKkq (ORCPT ); Mon, 9 Jul 2018 06:40:46 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:56596 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754433AbeGIKkp (ORCPT ); Mon, 9 Jul 2018 06:40:45 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 59F2F1682; Mon, 9 Jul 2018 03:40:45 -0700 (PDT) Received: from e103592.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 055E23F318; Mon, 9 Jul 2018 03:40:43 -0700 (PDT) Date: Mon, 9 Jul 2018 11:40:41 +0100 From: Dave Martin To: "Yandong.Zhao" Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, ard.biesheuvel@linaro.org, linux-kernel@vger.kernel.org, zhaoyd@thundersoft.com Subject: Re: [PATCH] arm64: neon: Add preemption protection for kernel_neon_busy Message-ID: <20180709104041.GC9486@e103592.cambridge.arm.com> References: <1531125935-19999-1-git-send-email-yandong77520@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1531125935-19999-1-git-send-email-yandong77520@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 09, 2018 at 04:45:35PM +0800, Yandong.Zhao wrote: > From: Yandong Zhao > > may_use_simd() can be called in any case and access kernel_neon_busy, > for example: BUG_ON(!may_use_simd()). This patch ensures that > migration will not occur during program access to kernel_neon_busy. > > Signed-off-by: Yandong Zhao (Duplicate patch, see [1] for discussion.) [...] Cheers ---Dave [1] [PATCH] arm64: neon: Do not access kernel_neon_busy with preemption enabled http://lists.infradead.org/pipermail/linux-arm-kernel/2018-July/589259.html