Messages in this thread | | | From | Romain Perier <> | Date | Tue, 28 Sep 2021 19:35:59 +0200 | Subject | Re: [PATCH][next][V2] rtc: msc313: Fix unintentional sign extension issues with left shift of a u16 |
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Hi,
Re-tested with rtctest and rtc-range, everything passed.
Le mar. 28 sept. 2021 à 15:46, Colin King <colin.king@canonical.com> a écrit : > > From: Colin Ian King <colin.king@canonical.com> > > Shifting the u16 value returned by readw by 16 bits to the left > will be promoted to a 32 bit signed int and then sign-extended > to an unsigned long. If the top bit of the readw is set then > the shifted value will be sign extended and the top 32 bits of > the result will be set. > > Fixes: be7d9c9161b9 ("rtc: Add support for the MSTAR MSC313 RTC") > Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Romain Perier <romain.perier@gmail.com>
Thanks, Romain
> --- > V2: Fix identical issue in msc313_rtc_read_time too. Thanks to Daniel Palmer > for noticing this ommission. > --- > drivers/rtc/rtc-msc313.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/rtc/rtc-msc313.c b/drivers/rtc/rtc-msc313.c > index 5f178d29cfd8..f3fde013c4b8 100644 > --- a/drivers/rtc/rtc-msc313.c > +++ b/drivers/rtc/rtc-msc313.c > @@ -53,7 +53,7 @@ static int msc313_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) > unsigned long seconds; > > seconds = readw(priv->rtc_base + REG_RTC_MATCH_VAL_L) > - | (readw(priv->rtc_base + REG_RTC_MATCH_VAL_H) << 16); > + | ((unsigned long)readw(priv->rtc_base + REG_RTC_MATCH_VAL_H) << 16); > > rtc_time64_to_tm(seconds, &alarm->time); > > @@ -122,7 +122,7 @@ static int msc313_rtc_read_time(struct device *dev, struct rtc_time *tm) > udelay(1); > > seconds = readw(priv->rtc_base + REG_RTC_CNT_VAL_L) > - | (readw(priv->rtc_base + REG_RTC_CNT_VAL_H) << 16); > + | ((unsigned long)readw(priv->rtc_base + REG_RTC_CNT_VAL_H) << 16); > > rtc_time64_to_tm(seconds, tm); > > -- > 2.32.0 >
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