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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 4E5EEC49ED7 for ; Fri, 20 Sep 2019 14:37:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A9B12080F for ; Fri, 20 Sep 2019 14:37:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392857AbfITOhq (ORCPT ); Fri, 20 Sep 2019 10:37:46 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35780 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388030AbfITOZA (ORCPT ); Fri, 20 Sep 2019 10:25:00 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iBJqD-0004xA-Vq; Fri, 20 Sep 2019 15:24:58 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iBJqD-0007r3-0m; Fri, 20 Sep 2019 15:24:57 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Kefeng Wang" , "Guenter Roeck" , "John Garry" Date: Fri, 20 Sep 2019 15:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 031/132] hwmon: (smsc47m1) Use request_muxed_region for Super-IO accesses In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.74-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Guenter Roeck commit d6410408ad2a798c4cc685252c1baa713be0ad69 upstream. Super-IO accesses may fail on a system with no or unmapped LPC bus. Also, other drivers may attempt to access the LPC bus at the same time, resulting in undefined behavior. Use request_muxed_region() to ensure that IO access on the requested address space is supported, and to ensure that access by multiple drivers is synchronized. Fixes: 8d5d45fb1468 ("I2C: Move hwmon drivers (2/3)") Reported-by: Kefeng Wang Reported-by: John Garry Cc: John Garry Acked-by: John Garry Signed-off-by: Guenter Roeck Signed-off-by: Ben Hutchings --- drivers/hwmon/smsc47m1.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) --- a/drivers/hwmon/smsc47m1.c +++ b/drivers/hwmon/smsc47m1.c @@ -73,16 +73,21 @@ superio_inb(int reg) /* logical device for fans is 0x0A */ #define superio_select() superio_outb(0x07, 0x0A) -static inline void +static inline int superio_enter(void) { + if (!request_muxed_region(REG, 2, DRVNAME)) + return -EBUSY; + outb(0x55, REG); + return 0; } static inline void superio_exit(void) { outb(0xAA, REG); + release_region(REG, 2); } #define SUPERIO_REG_ACT 0x30 @@ -495,8 +500,12 @@ static int __init smsc47m1_find(struct s { u8 val; unsigned short addr; + int err; + + err = superio_enter(); + if (err) + return err; - superio_enter(); val = force_id ? force_id : superio_inb(SUPERIO_REG_DEVID); /* @@ -572,13 +581,14 @@ static int __init smsc47m1_find(struct s static void smsc47m1_restore(const struct smsc47m1_sio_data *sio_data) { if ((sio_data->activate & 0x01) == 0) { - superio_enter(); - superio_select(); - - pr_info("Disabling device\n"); - superio_outb(SUPERIO_REG_ACT, sio_data->activate); - - superio_exit(); + if (!superio_enter()) { + superio_select(); + pr_info("Disabling device\n"); + superio_outb(SUPERIO_REG_ACT, sio_data->activate); + superio_exit(); + } else { + pr_warn("Failed to disable device\n"); + } } }