On Fri, 11 Feb 2022 12:26:28 +0000 Andre Przywara <andre.przywara@xxxxxxx> wrote: Hi Alessandro, Alexandre, I was wondering if you would consider taking this (as a fix)? This (time_gap > U32_MAX) comparison looks flawed by design, and we should use time_t these days anyway. Also, do you have an opinion on the other RTC patches? The linear day patch (v10 04/18)[1] and the broken-down alarm registers (v10 05/18)[2] were on the list for a while now and are needed by other SoCs as well (R329[3] and the RISC-V D1). Cheers, Andre [1] https://lore.kernel.org/linux-arm-kernel/20220211122643.1343315-5-andre.przywara@xxxxxxx/ [2] https://lore.kernel.org/linux-arm-kernel/20220211122643.1343315-6-andre.przywara@xxxxxxx/ [3] https://lore.kernel.org/linux-arm-kernel/20210802062212.73220-3-icenowy@xxxxxxxxxx/ > Using "unsigned long" for UNIX timestamps is never a good idea, and > comparing the value of such a variable against U32_MAX does not do > anything useful on 32-bit systems. > > Use the proper time64_t type when dealing with timestamps, and avoid > cutting down the time range unnecessarily. This also fixes the flawed > check for the alarm time being too far into the future. > > The check for this condition is actually somewhat theoretical, as the > RTC counts till 2033 only anyways, and 2^32 seconds from now is not > before the year 2157 - at which point I hope nobody will be using this > hardware anymore. > > Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> > Reviewed-by: Jernej Skrabec <jernej.skrabec@xxxxxxxxx> > --- > drivers/rtc/rtc-sun6i.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c > index 35b34d14a1db..dc3ae851841c 100644 > --- a/drivers/rtc/rtc-sun6i.c > +++ b/drivers/rtc/rtc-sun6i.c > @@ -139,7 +139,7 @@ struct sun6i_rtc_dev { > const struct sun6i_rtc_clk_data *data; > void __iomem *base; > int irq; > - unsigned long alarm; > + time64_t alarm; > > struct clk_hw hw; > struct clk_hw *int_osc; > @@ -511,10 +511,8 @@ static int sun6i_rtc_setalarm(struct device *dev, > struct rtc_wkalrm *wkalrm) struct sun6i_rtc_dev *chip = > dev_get_drvdata(dev); struct rtc_time *alrm_tm = &wkalrm->time; > struct rtc_time tm_now; > - unsigned long time_now = 0; > - unsigned long time_set = 0; > - unsigned long time_gap = 0; > - int ret = 0; > + time64_t time_now, time_set; > + int ret; > > ret = sun6i_rtc_gettime(dev, &tm_now); > if (ret < 0) { > @@ -529,9 +527,7 @@ static int sun6i_rtc_setalarm(struct device *dev, > struct rtc_wkalrm *wkalrm) return -EINVAL; > } > > - time_gap = time_set - time_now; > - > - if (time_gap > U32_MAX) { > + if ((time_set - time_now) > U32_MAX) { > dev_err(dev, "Date too far in the future\n"); > return -EINVAL; > } > @@ -540,7 +536,7 @@ static int sun6i_rtc_setalarm(struct device *dev, > struct rtc_wkalrm *wkalrm) writel(0, chip->base + SUN6I_ALRM_COUNTER); > usleep_range(100, 300); > > - writel(time_gap, chip->base + SUN6I_ALRM_COUNTER); > + writel(time_set - time_now, chip->base + SUN6I_ALRM_COUNTER); > chip->alarm = time_set; > > sun6i_rtc_setaie(wkalrm->enabled, chip);
