From patchwork Thu Aug 18 13:59:09 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 9288091 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 78750600CB for ; Thu, 18 Aug 2016 14:14:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 67ADA284EE for ; Thu, 18 Aug 2016 14:14:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 594E929249; Thu, 18 Aug 2016 14:14:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7F33A284EE for ; Thu, 18 Aug 2016 14:14:51 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 824A16EA64; Thu, 18 Aug 2016 14:14:50 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9E4FB6EA64 for ; Thu, 18 Aug 2016 14:14:49 +0000 (UTC) Received: from localhost (pes75-3-78-192-101-3.fbxo.proxad.net [78.192.101.3]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id C5812A18; Thu, 18 Aug 2016 14:14:48 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Subject: [PATCH 4.7 132/186] drm: Restore double clflush on the last partial cacheline Date: Thu, 18 Aug 2016 15:59:09 +0200 Message-Id: <20160818135937.901515407@linuxfoundation.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20160818135932.219369981@linuxfoundation.org> References: <20160818135932.219369981@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Cc: Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, Jason Ekstrand , Akash Goel , stable@vger.kernel.org, Daniel Vetter , Mika Kuoppala X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Wilson commit 396f5d62d1a5fd99421855a08ffdef8edb43c76e upstream. This effectively reverts commit afcd950cafea6e27b739fe7772cbbeed37d05b8b Author: Chris Wilson Date: Wed Jun 10 15:58:01 2015 +0100 drm: Avoid the double clflush on the last cache line in drm_clflush_virt_range() as we have observed issues with serialisation of the clflush operations on Baytrail+ Atoms with partial updates. Applying the double flush on the last cacheline forces that clflush to be ordered with respect to the previous clflush, and the mfence then protects against prefetches crossing the clflush boundary. The same issue can be demonstrated in userspace with igt/gem_exec_flush. Fixes: afcd950cafea6 (drm: Avoid the double clflush on the last cache...) Testcase: igt/gem_concurrent_blit Testcase: igt/gem_partial_pread_pwrite Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92845 Signed-off-by: Chris Wilson Cc: dri-devel@lists.freedesktop.org Cc: Akash Goel Cc: Imre Deak Cc: Daniel Vetter Cc: Jason Ekstrand Reviewed-by: Mika Kuoppala Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1467880930-23082-6-git-send-email-chris@chris-wilson.co.uk Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_cache.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/gpu/drm/drm_cache.c +++ b/drivers/gpu/drm/drm_cache.c @@ -136,6 +136,7 @@ drm_clflush_virt_range(void *addr, unsig mb(); for (; addr < end; addr += size) clflushopt(addr); + clflushopt(end - 1); /* force serialisation */ mb(); return; }