From patchwork Thu Jan 30 18:38:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 232375 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=-7.3 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_DBL_ABUSE_MALW, USER_AGENT_GIT 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 05802C33CB3 for ; Thu, 30 Jan 2020 18:44:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D091121734 for ; Thu, 30 Jan 2020 18:44:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580409875; bh=8OuebgqwLV2pZs9r42PHayOw/w5zaMYEWWmMvxUg8HA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kcaMe7p33nmacc2hz4Jl8S8d694wxdjPrRKYaWBNWCeltmPaEhb7+eCYofUbbS/LY gnFi6lOxxh63024d2tYyiTdWgOhqmXF6ZSvVgg/Jez1LkB8IORcmGpnQ4h7fuJGeTt HVlzMDhoau+icliBpsDY+boOOwqZSB0sycRO50FQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730844AbgA3Soc (ORCPT ); Thu, 30 Jan 2020 13:44:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:53724 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730840AbgA3Soc (ORCPT ); Thu, 30 Jan 2020 13:44:32 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 187DB21734; Thu, 30 Jan 2020 18:44:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580409871; bh=8OuebgqwLV2pZs9r42PHayOw/w5zaMYEWWmMvxUg8HA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N+Plv1Ekx4CPQy3dWcwe7eJVnUx9/ywa0AB8e1uEAOpvoc2Ht1k9HB+Em3GtlmldE qI1sktvZLtxyQgW/NiwFMC73wR65UAu6Bao7KfYfYJ2Q2c4Mf/7b7zhIR8wJqH2E3A PnAnrqKzPRhHewiiRNct5TzeONgGq+8j7vCscMCM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Zijlstra , Fenghua Yu , Tony Luck , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 067/110] drivers/net/b44: Change to non-atomic bit operations on pwol_mask Date: Thu, 30 Jan 2020 19:38:43 +0100 Message-Id: <20200130183622.595145543@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200130183613.810054545@linuxfoundation.org> References: <20200130183613.810054545@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Fenghua Yu [ Upstream commit f11421ba4af706cb4f5703de34fa77fba8472776 ] Atomic operations that span cache lines are super-expensive on x86 (not just to the current processor, but also to other processes as all memory operations are blocked until the operation completes). Upcoming x86 processors have a switch to cause such operations to generate a #AC trap. It is expected that some real time systems will enable this mode in BIOS. In preparation for this, it is necessary to fix code that may execute atomic instructions with operands that cross cachelines because the #AC trap will crash the kernel. Since "pwol_mask" is local and never exposed to concurrency, there is no need to set bits in pwol_mask using atomic operations. Directly operate on the byte which contains the bit instead of using __set_bit() to avoid any big endian concern due to type cast to unsigned long in __set_bit(). Suggested-by: Peter Zijlstra Signed-off-by: Fenghua Yu Signed-off-by: Tony Luck Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/broadcom/b44.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/broadcom/b44.c b/drivers/net/ethernet/broadcom/b44.c index 97ab0dd255522..1a7710c399d74 100644 --- a/drivers/net/ethernet/broadcom/b44.c +++ b/drivers/net/ethernet/broadcom/b44.c @@ -1519,8 +1519,10 @@ static int b44_magic_pattern(u8 *macaddr, u8 *ppattern, u8 *pmask, int offset) int ethaddr_bytes = ETH_ALEN; memset(ppattern + offset, 0xff, magicsync); - for (j = 0; j < magicsync; j++) - set_bit(len++, (unsigned long *) pmask); + for (j = 0; j < magicsync; j++) { + pmask[len >> 3] |= BIT(len & 7); + len++; + } for (j = 0; j < B44_MAX_PATTERNS; j++) { if ((B44_PATTERN_SIZE - len) >= ETH_ALEN) @@ -1532,7 +1534,8 @@ static int b44_magic_pattern(u8 *macaddr, u8 *ppattern, u8 *pmask, int offset) for (k = 0; k< ethaddr_bytes; k++) { ppattern[offset + magicsync + (j * ETH_ALEN) + k] = macaddr[k]; - set_bit(len++, (unsigned long *) pmask); + pmask[len >> 3] |= BIT(len & 7); + len++; } } return len - 1;