From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Nick Crews <ncrews@chromium.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>,
linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org,
Pavel Machek <pavel@ucw.cz>,
enric.balletbo@collabora.com, bleung@chromium.org,
dlaurie@chromium.org, djkurtz@chromium.org, dtor@google.com
Subject: Re: [PATCH v3] rtc: wilco-ec: Handle reading invalid times
Date: Tue, 1 Oct 2019 21:53:42 +0200 [thread overview]
Message-ID: <20191001195342.GH4106@piout.net> (raw)
In-Reply-To: <20190925203209.79941-1-ncrews@chromium.org>
Hi Nick,
On 25/09/2019 14:32:09-0600, Nick Crews wrote:
> If the RTC HW returns an invalid time, the rtc_year_days()
> call would crash. This patch adds error logging in this
> situation, and removes the tm_yday and tm_wday calculations.
> These fields should not be relied upon by userspace
> according to man rtc, and thus we don't need to calculate
> them.
>
> Signed-off-by: Nick Crews <ncrews@chromium.org>
> ---
> drivers/rtc/rtc-wilco-ec.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/rtc/rtc-wilco-ec.c b/drivers/rtc/rtc-wilco-ec.c
> index 8ad4c4e6d557..53da355d996a 100644
> --- a/drivers/rtc/rtc-wilco-ec.c
> +++ b/drivers/rtc/rtc-wilco-ec.c
> @@ -110,10 +110,15 @@ static int wilco_ec_rtc_read(struct device *dev, struct rtc_time *tm)
> tm->tm_mday = rtc.day;
> tm->tm_mon = rtc.month - 1;
> tm->tm_year = rtc.year + (rtc.century * 100) - 1900;
> - tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
> -
> - /* Don't compute day of week, we don't need it. */
> - tm->tm_wday = -1;
> + /* Ignore other tm fields, man rtc says userspace shouldn't use them. */
> +
> + if (rtc_valid_tm(tm)) {
> + dev_err(dev,
> + "Time from RTC is invalid: second=%u, minute=%u, hour=%u, day=%u, month=%u, year=%u, century=%u",
> + rtc.second, rtc.minute, rtc.hour, rtc.day, rtc.month,
> + rtc.year, rtc.century);
Do you mind using %ptR? At this point you already filled the tm struct
anyway and if you print century separately, you can infer tm_year.
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
next prev parent reply other threads:[~2019-10-01 19:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 20:32 [PATCH v3] rtc: wilco-ec: Handle reading invalid times Nick Crews
2019-09-25 20:51 ` Dmitry Torokhov
2019-10-01 19:53 ` Alexandre Belloni [this message]
2019-10-01 20:42 ` Dmitry Torokhov
2019-10-02 10:32 ` Alexandre Belloni
2019-10-02 15:20 ` Dmitry Torokhov
2019-10-02 15:34 ` Alexandre Belloni
2019-10-03 20:37 ` Nick Crews
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