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=-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=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 6CE09C33CB3 for ; Thu, 30 Jan 2020 18:47:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 414B4215A4 for ; Thu, 30 Jan 2020 18:47:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580410079; bh=KGVdJI4QeammafVVxIwwiX4/OvI88n2ymAv/vzMJ+04=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=08WQmBnERV965ne9Z+IHZnsCkNLvrpPr+S1t1VesQpxUQB0SFqNU0R88/znHqm+Qo C96j4aToAowMGmFM1wp5nrVFE4zOW4te+oAswMX/G3Fv7Psdl1o4PGru5VqKlC12hn RERAXQBRAk8HrgZifsXONHI733fK+I30H1xCMKZk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730931AbgA3Sr6 (ORCPT ); Thu, 30 Jan 2020 13:47:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:58720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731451AbgA3Srz (ORCPT ); Thu, 30 Jan 2020 13:47:55 -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 71A86217BA; Thu, 30 Jan 2020 18:47:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580410074; bh=KGVdJI4QeammafVVxIwwiX4/OvI88n2ymAv/vzMJ+04=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LopmQZ9SnYjPcWN/QgYavm6eTeTvfzRT+zddfejDfpGN25AKzWsP+U30OSXvWfM9s Q0DNXl8vUM5g2aFz6euSry8rWtVWIRE/E7ydj+OeUOdoD+Zboc6ElNVXBRS7GntQzr ZUPkxFYmNQ7fj/ODJYOu1ZoO2gQQhVAfDSrtXZKA= 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 4.19 36/55] drivers/net/b44: Change to non-atomic bit operations on pwol_mask Date: Thu, 30 Jan 2020 19:39:17 +0100 Message-Id: <20200130183615.120752961@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200130183608.563083888@linuxfoundation.org> References: <20200130183608.563083888@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 e445ab724827f..88f8d31e4c833 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; -- 2.20.1