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From: Icenowy Zheng <icenowy@sipeed.com>
To: Rob Herring <robh+dt@kernel.org>,
	Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Andre Przywara <andre.przywara@arm.com>,
	Samuel Holland <samuel@sholland.org>
Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: [PATCH 01/17] rtc: sun6i: Fix time overflow handling
Date: Mon,  2 Aug 2021 14:21:56 +0800	[thread overview]
Message-ID: <20210802062212.73220-2-icenowy@sipeed.com> (raw)
In-Reply-To: <20210802062212.73220-1-icenowy@sipeed.com>

From: Andre Przywara <andre.przywara@arm.com>

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@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
---
 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 adec1b14a8de..c551ebf0ac00 100644
--- a/drivers/rtc/rtc-sun6i.c
+++ b/drivers/rtc/rtc-sun6i.c
@@ -138,7 +138,7 @@ 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;
@@ -510,10 +510,8 @@ 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) {
@@ -528,9 +526,7 @@ 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;
 	}
@@ -539,7 +535,7 @@ 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);
-- 
2.30.2


  reply	other threads:[~2021-08-02  6:30 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02  6:21 [PATCH 00/17] Basical Allwinner R329 support Icenowy Zheng
2021-08-02  6:21 ` Icenowy Zheng [this message]
2021-08-02  6:21 ` [PATCH 02/17] rtc: sun6i: Add support for linear day storage Icenowy Zheng
2021-08-02  6:21 ` [PATCH 03/17] rtc: sun6i: Add support for broken-down alarm registers Icenowy Zheng
2021-08-02  6:21 ` [PATCH 04/17] dt-bindings: rtc: sun6i: add compatible string for R329 RTC Icenowy Zheng
2021-08-06 21:39   ` Rob Herring
2021-08-02  6:22 ` [PATCH 05/17] rtc: sun6i: add support " Icenowy Zheng
2021-08-02  6:22 ` [PATCH 06/17] dt-bindings: pinctrl: document Allwinner R329 PIO and R-PIO Icenowy Zheng
2021-08-06 21:40   ` Rob Herring
2021-08-18  8:48   ` Maxime Ripard
2021-08-19  2:40   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 07/17] pinctrl: sunxi: add support for R329 CPUX pin controller Icenowy Zheng
2021-08-11  9:23   ` Linus Walleij
2021-08-18  8:48   ` Maxime Ripard
2021-08-19  3:09   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 08/17] pinctrl: sunxi: add support for R329 R-PIO " Icenowy Zheng
2021-08-18  8:52   ` Maxime Ripard
2021-08-19  3:22   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 09/17] dt-bindings: clock: sunxi-ng: add compatibles for R329 CCUs Icenowy Zheng
2021-08-06 21:41   ` Rob Herring
2021-08-02  6:22 ` [PATCH 10/17] clk: sunxi=ng: add support for R329 R-CCU Icenowy Zheng
2021-08-06 21:42   ` Rob Herring
2021-08-18  8:50   ` Maxime Ripard
2021-08-20  0:55   ` Samuel Holland
2021-08-20  4:34     ` Jernej Škrabec
2021-08-25 14:50       ` Maxime Ripard
2021-08-25 15:03         ` Jernej Škrabec
2021-08-25 15:37           ` Maxime Ripard
2021-08-26  0:20       ` Samuel Holland
2021-08-02  6:22 ` [PATCH 11/17] clk: sunxi-ng: add support for Allwinner R329 CCU Icenowy Zheng
2021-08-06 21:42   ` Rob Herring
2021-08-20  2:41   ` Samuel Holland
2021-08-25 14:54     ` Maxime Ripard
2021-08-02  6:22 ` [PATCH 12/17] dt-bindings: mmc: sunxi-mmc: add R329 MMC compatible string Icenowy Zheng
2021-08-06 21:42   ` Rob Herring
2021-08-18  8:47   ` Maxime Ripard
2021-08-02  6:22 ` [PATCH 13/17] mmc: sunxi: add support for R329 MMC controllers Icenowy Zheng
2021-08-18  8:47   ` Maxime Ripard
2021-08-20  2:43   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 14/17] dt-bindings: arm: sunxi: add compatible strings for Sipeed MaixSense Icenowy Zheng
2021-08-06 21:43   ` Rob Herring
2021-08-18  9:03   ` Maxime Ripard
2021-08-02  6:22 ` [PATCH 15/17] arm64: allwinner: dts: add DTSI file for R329 SoC Icenowy Zheng
2021-08-18  9:01   ` Maxime Ripard
     [not found]     ` <74F51516-2470-4A49-972B-E19D8EDD9A3D@sipeed.com>
2021-08-19  2:32       ` Samuel Holland
2021-08-20  3:06         ` Samuel Holland
2021-08-25 15:00           ` Maxime Ripard
2021-08-20  2:59   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 16/17] arm64: allwinner: dts: r329: add DTSI file for Sipeed Maix IIA Icenowy Zheng
2021-08-02  6:22 ` [PATCH 17/17] arm64: allwinner: dts: r329: add support for Sipeed MaixSense Icenowy Zheng
2021-08-10 11:04 ` [PATCH 00/17] Basical Allwinner R329 support Ulf Hansson

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