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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEA1EC4332F for ; Mon, 12 Dec 2022 13:29:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232194AbiLLN3L (ORCPT ); Mon, 12 Dec 2022 08:29:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232784AbiLLN2x (ORCPT ); Mon, 12 Dec 2022 08:28:53 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 628DE13E0B for ; Mon, 12 Dec 2022 05:28:52 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1B784B80D52 for ; Mon, 12 Dec 2022 13:28:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF438C433D2; Mon, 12 Dec 2022 13:28:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670851729; bh=cb95x2E/PWeBwFYg+kgog4i3ZpoGV1BYXZPIpRMrf3o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M4BJyyHLJon0q0Wp1eH9GaO/VHqxpK8GOEr+aYlUvAIjLlKqSBPcfiM41lOZXlqr4 zOKL5AWWyZejnrQKbgupwWGJHm1TtzOUWuVGnddSpL0HFhTMAq2BhRsnwhZpuGgL9h 3MzGdw/cL/NxZEog9G3AsQPSW/iNhZpINLJ7o0lY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Mateusz=20Jo=C5=84czyk?= , Alessandro Zummo , Alexandre Belloni , Sasha Levin Subject: [PATCH 5.15 032/123] rtc: cmos: avoid UIP when writing alarm time Date: Mon, 12 Dec 2022 14:16:38 +0100 Message-Id: <20221212130928.257274291@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221212130926.811961601@linuxfoundation.org> References: <20221212130926.811961601@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mateusz Jończyk [ Upstream commit cd17420ebea580c22dd3a93f7237de3d2cfafc37 ] Some Intel chipsets disconnect the time and date RTC registers when the clock update is in progress: during this time reads may return bogus values and writes fail silently. This includes the RTC alarm registers. [1] cmos_set_alarm() did not take account for that, fix it. [1] 7th Generation Intel ® Processor Family I/O for U/Y Platforms [...] Datasheet, Volume 1 of 2 (Intel's Document Number: 334658-006) Page 208 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/7th-and-8th-gen-core-family-mobile-u-y-processor-lines-i-o-datasheet-vol-1.pdf "If a RAM read from the ten time and date bytes is attempted during an update cycle, the value read do not necessarily represent the true contents of those locations. Any RAM writes under the same conditions are ignored." Signed-off-by: Mateusz Jończyk Cc: Alessandro Zummo Cc: Alexandre Belloni Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20211210200131.153887-10-mat.jonczyk@o2.pl Signed-off-by: Sasha Levin --- drivers/rtc/rtc-cmos.c | 107 +++++++++++++++++++++++++---------------- 1 file changed, 66 insertions(+), 41 deletions(-) diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index b90a603d6b12..a3297a9cbc59 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -444,10 +444,57 @@ static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t) return 0; } +struct cmos_set_alarm_callback_param { + struct cmos_rtc *cmos; + unsigned char mon, mday, hrs, min, sec; + struct rtc_wkalrm *t; +}; + +/* Note: this function may be executed by mc146818_avoid_UIP() more then + * once + */ +static void cmos_set_alarm_callback(unsigned char __always_unused seconds, + void *param_in) +{ + struct cmos_set_alarm_callback_param *p = + (struct cmos_set_alarm_callback_param *)param_in; + + /* next rtc irq must not be from previous alarm setting */ + cmos_irq_disable(p->cmos, RTC_AIE); + + /* update alarm */ + CMOS_WRITE(p->hrs, RTC_HOURS_ALARM); + CMOS_WRITE(p->min, RTC_MINUTES_ALARM); + CMOS_WRITE(p->sec, RTC_SECONDS_ALARM); + + /* the system may support an "enhanced" alarm */ + if (p->cmos->day_alrm) { + CMOS_WRITE(p->mday, p->cmos->day_alrm); + if (p->cmos->mon_alrm) + CMOS_WRITE(p->mon, p->cmos->mon_alrm); + } + + if (use_hpet_alarm()) { + /* + * FIXME the HPET alarm glue currently ignores day_alrm + * and mon_alrm ... + */ + hpet_set_alarm_time(p->t->time.tm_hour, p->t->time.tm_min, + p->t->time.tm_sec); + } + + if (p->t->enabled) + cmos_irq_enable(p->cmos, RTC_AIE); +} + static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) { struct cmos_rtc *cmos = dev_get_drvdata(dev); - unsigned char mon, mday, hrs, min, sec, rtc_control; + struct cmos_set_alarm_callback_param p = { + .cmos = cmos, + .t = t + }; + unsigned char rtc_control; int ret; /* This not only a rtc_op, but also called directly */ @@ -458,11 +505,11 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) if (ret < 0) return ret; - mon = t->time.tm_mon + 1; - mday = t->time.tm_mday; - hrs = t->time.tm_hour; - min = t->time.tm_min; - sec = t->time.tm_sec; + p.mon = t->time.tm_mon + 1; + p.mday = t->time.tm_mday; + p.hrs = t->time.tm_hour; + p.min = t->time.tm_min; + p.sec = t->time.tm_sec; spin_lock_irq(&rtc_lock); rtc_control = CMOS_READ(RTC_CONTROL); @@ -470,43 +517,21 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { /* Writing 0xff means "don't care" or "match all". */ - mon = (mon <= 12) ? bin2bcd(mon) : 0xff; - mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff; - hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff; - min = (min < 60) ? bin2bcd(min) : 0xff; - sec = (sec < 60) ? bin2bcd(sec) : 0xff; + p.mon = (p.mon <= 12) ? bin2bcd(p.mon) : 0xff; + p.mday = (p.mday >= 1 && p.mday <= 31) ? bin2bcd(p.mday) : 0xff; + p.hrs = (p.hrs < 24) ? bin2bcd(p.hrs) : 0xff; + p.min = (p.min < 60) ? bin2bcd(p.min) : 0xff; + p.sec = (p.sec < 60) ? bin2bcd(p.sec) : 0xff; } - spin_lock_irq(&rtc_lock); - - /* next rtc irq must not be from previous alarm setting */ - cmos_irq_disable(cmos, RTC_AIE); - - /* update alarm */ - CMOS_WRITE(hrs, RTC_HOURS_ALARM); - CMOS_WRITE(min, RTC_MINUTES_ALARM); - CMOS_WRITE(sec, RTC_SECONDS_ALARM); - - /* the system may support an "enhanced" alarm */ - if (cmos->day_alrm) { - CMOS_WRITE(mday, cmos->day_alrm); - if (cmos->mon_alrm) - CMOS_WRITE(mon, cmos->mon_alrm); - } - - if (use_hpet_alarm()) { - /* - * FIXME the HPET alarm glue currently ignores day_alrm - * and mon_alrm ... - */ - hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, - t->time.tm_sec); - } - - if (t->enabled) - cmos_irq_enable(cmos, RTC_AIE); - - spin_unlock_irq(&rtc_lock); + /* + * Some Intel chipsets disconnect the alarm registers when the clock + * update is in progress - during this time writes fail silently. + * + * Use mc146818_avoid_UIP() to avoid this. + */ + if (!mc146818_avoid_UIP(cmos_set_alarm_callback, &p)) + return -EIO; cmos->alarm_expires = rtc_tm_to_time64(&t->time); -- 2.35.1