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=-12.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY, USER_AGENT_GIT autolearn=ham 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 431A1C433F5 for ; Sun, 12 Sep 2021 12:45:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 202056108F for ; Sun, 12 Sep 2021 12:45:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235168AbhILMqX (ORCPT ); Sun, 12 Sep 2021 08:46:23 -0400 Received: from mx-out.tlen.pl ([193.222.135.145]:24849 "EHLO mx-out.tlen.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235050AbhILMqW (ORCPT ); Sun, 12 Sep 2021 08:46:22 -0400 Received: (wp-smtpd smtp.tlen.pl 9608 invoked from network); 12 Sep 2021 14:45:06 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=o2.pl; s=1024a; t=1631450706; bh=8r8xgy65ZR76BqRT88sVTuFNy8P/G7PRukyy/pHFjGc=; h=From:To:Cc:Subject; b=K6i/AfpI2JblyZsm9V+GvTJWV31TtCKQesBWKUwQ33aOM+7CEg51KQ6+5H2eyy3Vt WymFO1u8F97nKmS9OlZANRD7gr86txHItNwMoiOg7SKT2QxT20YQ8uFur7LhS1XxQ9 FGNONQDPmh7Nm0s+h8kVSPBheBnfVZwFCFRhe5A8= Received: from aafh223.neoplus.adsl.tpnet.pl (HELO localhost.localdomain) (mat.jonczyk@o2.pl@[83.4.137.223]) (envelope-sender ) by smtp.tlen.pl (WP-SMTPD) with SMTP for ; 12 Sep 2021 14:45:06 +0200 From: =?UTF-8?q?Mateusz=20Jo=C5=84czyk?= To: linux-rtc@vger.kernel.org Cc: =?UTF-8?q?Mateusz=20Jo=C5=84czyk?= , Alessandro Zummo , Alexandre Belloni Subject: [TEST PATCH] rtc-cmos: cmos_read_alarm bug demonstration Date: Sun, 12 Sep 2021 14:44:53 +0200 Message-Id: <20210912124453.81925-1-mat.jonczyk@o2.pl> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210912124214.81853-3-mat.jonczyk@o2.pl> References: <20210912124214.81853-3-mat.jonczyk@o2.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-WP-MailID: 98eab5c8cd5e189c9ff73a4c4b83faaf X-WP-AV: skaner antywirusowy Poczty o2 X-WP-SPAM: NO 0000000 [0ZNE] Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org Before my commit "rtc-cmos: dont touch alarm registers during update", applying this patch and reading the CMOS time like so: while true; do cat /sys/class/rtc/rtc0/time ; sleep 0.5; done produces errors in dmesg. Signed-off-by: Mateusz Jończyk Cc: Alessandro Zummo Cc: Alexandre Belloni --- drivers/rtc/rtc-cmos.c | 61 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index f353a41dfe8c..c24465f7bed4 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -43,6 +43,9 @@ #include #endif +#include +#include + /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */ #include @@ -220,6 +223,8 @@ static inline void cmos_write_bank2(unsigned char val, unsigned char addr) /*----------------------------------------------------------------*/ +static void cmos_read_alarm_uip_debugging(struct device *dev); + static int cmos_read_time(struct device *dev, struct rtc_time *t) { /* @@ -234,6 +239,8 @@ static int cmos_read_time(struct device *dev, struct rtc_time *t) * That'll make Y3K compatility (year > 2070) easy! */ mc146818_get_time(t); + + cmos_read_alarm_uip_debugging(dev); return 0; } @@ -348,6 +355,60 @@ static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t) return 0; } +static void cmos_read_alarm_uip_debugging(struct device *dev) +{ + unsigned long flags; + unsigned char rtc_uip_baseline, rtc_uip; + struct rtc_wkalrm t_baseline, t; + ktime_t time_start, time_end; + int i; + + spin_lock_irqsave(&rtc_lock, flags); + rtc_uip_baseline = CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP; + spin_unlock_irqrestore(&rtc_lock, flags); + + cmos_read_alarm(dev, &t_baseline); + + time_start = ktime_get(); + + for (i = 0; i < 2000; i++) { + spin_lock_irqsave(&rtc_lock, flags); + rtc_uip = CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP; + spin_unlock_irqrestore(&rtc_lock, flags); + + cmos_read_alarm(dev, &t); + + if (t_baseline.time.tm_sec != t.time.tm_sec) { + dev_err(dev, + "Inconsistent alarm tm_sec value: %d != %d (RTC_UIP = %d; %d)\n", + t_baseline.time.tm_sec, + t.time.tm_sec, + rtc_uip_baseline, rtc_uip); + } + if (t_baseline.time.tm_min != t.time.tm_min) { + dev_err(dev, + "Inconsistent alarm tm_min value: %d != %d (RTC_UIP = %d; %d)\n", + t_baseline.time.tm_min, + t.time.tm_min, + rtc_uip_baseline, rtc_uip); + } + if (t_baseline.time.tm_hour != t.time.tm_hour) { + dev_err(dev, + "Inconsistent alarm tm_hour value: %d != %d (RTC_UIP = %d; %d)\n", + t_baseline.time.tm_hour, + t.time.tm_hour, + rtc_uip_baseline, rtc_uip); + } + + } + + time_end = ktime_get(); + + pr_info_ratelimited("%s: loop executed in %lld ns\n", + __func__, ktime_to_ns(ktime_sub(time_end, time_start))); +} + + static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control) { unsigned char rtc_intr; -- 2.25.1