From patchwork Mon Feb 3 16:19:09 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: 232215 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_BLOCKED, URIBL_DBL_ABUSE_MALW, USER_AGENT_GIT autolearn=unavailable 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 0977AC3524F for ; Mon, 3 Feb 2020 16:29:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D22A32086A for ; Mon, 3 Feb 2020 16:29:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580747386; bh=c+d813cZMCYf0vAj2pTZXXiLVWj7SVH0DsY+S6RlMds=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CZzCmCHCDN6mRZhLlcdY4iWSCjKpmolL2lSy3zbFMSPMOcongHFr9ZbhSxLEZGOSE nNnwr9NAbUILE8ZYIfxVAf4RSF4j/3IDU6sU/P/Ey0qkSsPaYeliui//DJr1moYOVJ vWdTQeLz312rYYLg4aPHxeUw6Ufy98sHMYWKkZi4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729849AbgBCQ3p (ORCPT ); Mon, 3 Feb 2020 11:29:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:41836 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729847AbgBCQ3p (ORCPT ); Mon, 3 Feb 2020 11:29:45 -0500 Received: from localhost (unknown [104.132.45.99]) (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 6CE9E20838; Mon, 3 Feb 2020 16:29:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580747384; bh=c+d813cZMCYf0vAj2pTZXXiLVWj7SVH0DsY+S6RlMds=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k3z1dP6A9kCFsm/oeTRsd1ASuhOeJ2eMUTFKmld2stU3bS0tOr2JcKBN+fUYgtLFd FnEZlj9uQD8AAlYvsLrrvLBAB8JnPk731bWBKSvb5bCQIFn3o9pgE38VdRR88KhjYf 7QwYzB/NEFiqGzvM1F4OjZ4+ruT/LcYsvoFwIPPU= 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 4.14 24/89] drivers/net/b44: Change to non-atomic bit operations on pwol_mask Date: Mon, 3 Feb 2020 16:19:09 +0000 Message-Id: <20200203161920.127855118@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200203161916.847439465@linuxfoundation.org> References: <20200203161916.847439465@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 a1125d10c8255..8b9a0ce1d29f5 100644 --- a/drivers/net/ethernet/broadcom/b44.c +++ b/drivers/net/ethernet/broadcom/b44.c @@ -1521,8 +1521,10 @@ 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) @@ -1534,7 +1536,8 @@ 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;