From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1521561-1519217343-5-10056535323261888357 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519217343; b=pwxp6chf9AVqPmgtvDEJeQeb174m5tkgDrfy2n6TvZ67tPd Gvyi8K7xQ8T4DQYqb6z1gopDsSEYtU99OHxj8M9i7HZWd4/Z/fC/ixH2k7fD8ljP TNvv9nBtRYiIaZHjCfxz2gU8UaAzbPh6MQiXGJFNMOivmm+86qw4y+P3ntMe836p VOYzNCXh6tyYbCzTiVohARUTAIPEvSMMv0LAHnU17B7OcXkvH8kbjYSo6rt+VTVZ V5ySzJhtVcWupCXKe5zDCCS647DUIYn8b0AVLIRzoDMGwWwTE1F4+RqyTTdOLK0y Bi7kD7ywiB5/92T2koXuBQog2AYKeYPWp93DuMg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1519217343; bh=BTWWqZEL7rumeA7PmAXgL6XuqB cVAj4mqlF1bbrAC9Q=; b=E+Qf5T9Pwt0WgXC+WCHO6ed3uGNXQVLIHPUiGBy7Lr QmiPJ3cAIKOejFgy0QeV0NwYwYsS80TsIi2UhGk/8FJxi8iCdjb83h2VeMbSdRrg aA34Dd5ap3SZ7mp87su6Urji1fXnxSz33Dr4PW89S9pqgUhKqSKkOeudFbRvIe3n fVHzFco5jifb3uKCgCFCHZdoWycsWEi2h+s5aP7W48hy2Jci541yl1uAbdMjingD bDG8W7cXihxFHe9Jq9g6jJd77MjAJdR4qDORSfw199FcTPV9wumEe3T/E3F4tXC6 BMaepoWG1BC6+BLRZDLv4ITrS7DOPs+rOqN/zmeNBifQ== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933915AbeBUMq2 (ORCPT ); Wed, 21 Feb 2018 07:46:28 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:59638 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933905AbeBUMq0 (ORCPT ); Wed, 21 Feb 2018 07:46:26 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stewart Smith , Michael Ellerman Subject: [PATCH 4.4 12/33] rtc-opal: Fix handling of firmware error codes, prevent busy loops Date: Wed, 21 Feb 2018 13:44:55 +0100 Message-Id: <20180221124410.314449386@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180221124409.564661689@linuxfoundation.org> References: <20180221124409.564661689@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stewart Smith commit 5b8b58063029f02da573120ef4dc9079822e3cda upstream. According to the OPAL docs: skiboot-5.2.5/doc/opal-api/opal-rtc-read-3.txt skiboot-5.2.5/doc/opal-api/opal-rtc-write-4.txt OPAL_HARDWARE may be returned from OPAL_RTC_READ or OPAL_RTC_WRITE and this indicates either a transient or permanent error. Prior to this patch, Linux was not dealing with OPAL_HARDWARE being a permanent error particularly well, in that you could end up in a busy loop. This was not too hard to trigger on an AMI BMC based OpenPOWER machine doing a continuous "ipmitool mc reset cold" to the BMC, the result of that being that we'd get stuck in an infinite loop in opal_get_rtc_time(). We now retry a few times before returning the error higher up the stack. Fixes: 16b1d26e77b1 ("rtc/tpo: Driver to support rtc and wakeup on PowerNV platform") Cc: stable@vger.kernel.org # v3.19+ Signed-off-by: Stewart Smith Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/rtc-opal.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/drivers/rtc/rtc-opal.c +++ b/drivers/rtc/rtc-opal.c @@ -58,6 +58,7 @@ static void tm_to_opal(struct rtc_time * static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm) { long rc = OPAL_BUSY; + int retries = 10; u32 y_m_d; u64 h_m_s_ms; __be32 __y_m_d; @@ -67,8 +68,11 @@ static int opal_get_rtc_time(struct devi rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms); if (rc == OPAL_BUSY_EVENT) opal_poll_events(NULL); - else + else if (retries-- && (rc == OPAL_HARDWARE + || rc == OPAL_INTERNAL_ERROR)) msleep(10); + else if (rc != OPAL_BUSY && rc != OPAL_BUSY_EVENT) + break; } if (rc != OPAL_SUCCESS) @@ -84,6 +88,7 @@ static int opal_get_rtc_time(struct devi static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm) { long rc = OPAL_BUSY; + int retries = 10; u32 y_m_d = 0; u64 h_m_s_ms = 0; @@ -92,8 +97,11 @@ static int opal_set_rtc_time(struct devi rc = opal_rtc_write(y_m_d, h_m_s_ms); if (rc == OPAL_BUSY_EVENT) opal_poll_events(NULL); - else + else if (retries-- && (rc == OPAL_HARDWARE + || rc == OPAL_INTERNAL_ERROR)) msleep(10); + else if (rc != OPAL_BUSY && rc != OPAL_BUSY_EVENT) + break; } return rc == OPAL_SUCCESS ? 0 : -EIO;