From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752478AbeCZPkD (ORCPT ); Mon, 26 Mar 2018 11:40:03 -0400 Received: from mail-oi0-f67.google.com ([209.85.218.67]:35285 "EHLO mail-oi0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751868AbeCZPkB (ORCPT ); Mon, 26 Mar 2018 11:40:01 -0400 X-Google-Smtp-Source: AIpwx4/bWfWT2PvWsv+vUnZ10vkazXzZxPdAi5dwta4JuPrnVXO6ryb5n0dTcbj5tcLqYUafKO1q8A== From: Stuart Hayes Subject: [PATCH v2] dell_rbu: make firmware payload memory uncachable To: linux-kernel@vger.kernel.org Message-ID: <8c18af18-17cf-57c5-5d57-ed3878d8a004@gmail.com> Date: Mon, 26 Mar 2018 10:39:57 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The dell_rbu driver takes firmware update payloads and puts them in memory so the system BIOS can find them after a reboot. This sometimes fails (though rarely), because the memory containing the payload is in the CPU cache but never gets written back to main memory before the system is rebooted (CPU cache contents are lost on reboot). With this patch, the payload memory will be changed to uncachable to ensure that the payload is actually in main memory before the system is rebooted. Signed-off-by: Stuart Hayes --- v2 Added include, removed extra parentheses This patch has no maintainer. diff --git a/drivers/firmware/dell_rbu.c b/drivers/firmware/dell_rbu.c index 2f452f1f7c8a..640a88c3418d 100644 --- a/drivers/firmware/dell_rbu.c +++ b/drivers/firmware/dell_rbu.c @@ -45,6 +45,7 @@ #include #include #include +#include MODULE_AUTHOR("Abhay Salunke "); MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems"); @@ -180,6 +181,11 @@ static int create_packet(void *data, size_t length) invalid_addr_packet_array[idx++] = packet_data_temp_buf; packet_data_temp_buf = NULL; } + /* + * set to uncachable or it may never get written back before + * reboot + */ + set_memory_uc(packet_data_temp_buf, 1 << ordernum); } spin_lock(&rbu_data.lock); @@ -349,6 +355,7 @@ static void packet_empty_list(void) * to make sure there are no stale RBU packets left in memory */ memset(newpacket->data, 0, rbu_data.packetsize); + set_memory_wb(newpacket->data, 1 << newpacket->ordernum); free_pages((unsigned long) newpacket->data, newpacket->ordernum); kfree(newpacket);