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=2.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,UNWANTED_LANGUAGE_BODY,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 15A20C433EF for ; Tue, 12 Jun 2018 05:20:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C654A208B0 for ; Tue, 12 Jun 2018 05:20:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C654A208B0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932436AbeFLFT7 (ORCPT ); Tue, 12 Jun 2018 01:19:59 -0400 Received: from gate.crashing.org ([63.228.1.57]:51955 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932137AbeFLFT5 (ORCPT ); Tue, 12 Jun 2018 01:19:57 -0400 Received: from pasglop.ozlabs.ibm.com (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w5C5JDa3008698; Tue, 12 Jun 2018 00:19:17 -0500 From: Benjamin Herrenschmidt To: openbmc@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org, Joel Stanley , Andrew Jeffery , Greg Kroah-Hartman , Benjamin Herrenschmidt Subject: [RFC PATCH 1/5] fsi/scom: Add mutex around FSI2PIB accesses Date: Tue, 12 Jun 2018 15:19:07 +1000 Message-Id: <20180612051911.20690-2-benh@kernel.crashing.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180612051911.20690-1-benh@kernel.crashing.org> References: <20180612051911.20690-1-benh@kernel.crashing.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Otherwise, multiple clients can open the driver and attempt to access the PIB at the same time, thus clobbering each other in the process. Signed-off-by: Benjamin Herrenschmidt --- drivers/fsi/fsi-scom.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c index c8eb5e5b94a7..3cba0eb645e1 100644 --- a/drivers/fsi/fsi-scom.c +++ b/drivers/fsi/fsi-scom.c @@ -37,6 +37,7 @@ struct scom_device { struct list_head link; struct fsi_device *fsi_dev; struct miscdevice mdev; + struct mutex lock; char name[32]; int idx; }; @@ -53,21 +54,26 @@ static int put_scom(struct scom_device *scom_dev, uint64_t value, int rc; uint32_t data; + mutex_lock(&scom_dev->lock); + data = cpu_to_be32((value >> 32) & 0xffffffff); rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data, sizeof(uint32_t)); if (rc) - return rc; + goto bail; data = cpu_to_be32(value & 0xffffffff); rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data, sizeof(uint32_t)); if (rc) - return rc; + goto bail; data = cpu_to_be32(SCOM_WRITE_CMD | addr); - return fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, sizeof(uint32_t)); + bail: + mutex_unlock(&scom_dev->lock); + return rc; } static int get_scom(struct scom_device *scom_dev, uint64_t *value, @@ -76,27 +82,31 @@ static int get_scom(struct scom_device *scom_dev, uint64_t *value, uint32_t result, data; int rc; + + mutex_lock(&scom_dev->lock); *value = 0ULL; data = cpu_to_be32(addr); rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, sizeof(uint32_t)); if (rc) - return rc; + goto bail; rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &result, sizeof(uint32_t)); if (rc) - return rc; + goto bail; *value |= (uint64_t)cpu_to_be32(result) << 32; rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result, sizeof(uint32_t)); if (rc) - return rc; + goto bail; *value |= cpu_to_be32(result); - return 0; + bail: + mutex_unlock(&scom_dev->lock); + return rc; } static ssize_t scom_read(struct file *filep, char __user *buf, size_t len, @@ -183,6 +193,7 @@ static int scom_probe(struct device *dev) if (!scom) return -ENOMEM; + mutex_init(&scom->lock); scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL); snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx); scom->fsi_dev = fsi_dev; -- 2.17.0