From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/rtc/rtc-mt6397.c | 354 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 354 insertions(+) create mode 100644 drivers/rtc/rtc-mt6397.c (limited to 'drivers/rtc/rtc-mt6397.c') diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c new file mode 100644 index 000000000..3d857681f --- /dev/null +++ b/drivers/rtc/rtc-mt6397.c @@ -0,0 +1,354 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* +* Copyright (c) 2014-2015 MediaTek Inc. +* Author: Tianping.Fang +*/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc) +{ + int ret; + u32 data; + + ret = regmap_write(rtc->regmap, rtc->addr_base + rtc->data->wrtgr, 1); + if (ret < 0) + return ret; + + ret = regmap_read_poll_timeout(rtc->regmap, + rtc->addr_base + RTC_BBPU, data, + !(data & RTC_BBPU_CBUSY), + MTK_RTC_POLL_DELAY_US, + MTK_RTC_POLL_TIMEOUT); + if (ret < 0) + dev_err(rtc->rtc_dev->dev.parent, + "failed to write WRTGR: %d\n", ret); + + return ret; +} + +static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data) +{ + struct mt6397_rtc *rtc = data; + u32 irqsta, irqen; + int ret; + + ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_STA, &irqsta); + if ((ret >= 0) && (irqsta & RTC_IRQ_STA_AL)) { + rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); + irqen = irqsta & ~RTC_IRQ_EN_AL; + mutex_lock(&rtc->lock); + if (regmap_write(rtc->regmap, rtc->addr_base + RTC_IRQ_EN, + irqen) == 0) + mtk_rtc_write_trigger(rtc); + mutex_unlock(&rtc->lock); + + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int __mtk_rtc_read_time(struct mt6397_rtc *rtc, + struct rtc_time *tm, int *sec) +{ + int ret; + u16 data[RTC_OFFSET_COUNT]; + + mutex_lock(&rtc->lock); + ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC, + data, RTC_OFFSET_COUNT); + if (ret < 0) + goto exit; + + tm->tm_sec = data[RTC_OFFSET_SEC]; + tm->tm_min = data[RTC_OFFSET_MIN]; + tm->tm_hour = data[RTC_OFFSET_HOUR]; + tm->tm_mday = data[RTC_OFFSET_DOM]; + tm->tm_wday = data[RTC_OFFSET_DOW]; + tm->tm_mon = data[RTC_OFFSET_MTH] & RTC_TC_MTH_MASK; + tm->tm_year = data[RTC_OFFSET_YEAR]; + + ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC, sec); +exit: + mutex_unlock(&rtc->lock); + return ret; +} + +static int mtk_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct mt6397_rtc *rtc = dev_get_drvdata(dev); + int sec, ret; + + do { + ret = __mtk_rtc_read_time(rtc, tm, &sec); + if (ret < 0) + goto exit; + } while (sec < tm->tm_sec); + + /* HW register start mon/wday from one, but tm_mon/tm_wday start from zero. */ + tm->tm_mon--; + tm->tm_wday--; + +exit: + return ret; +} + +static int mtk_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct mt6397_rtc *rtc = dev_get_drvdata(dev); + int ret; + u16 data[RTC_OFFSET_COUNT]; + + tm->tm_mon++; + tm->tm_wday++; + + data[RTC_OFFSET_SEC] = tm->tm_sec; + data[RTC_OFFSET_MIN] = tm->tm_min; + data[RTC_OFFSET_HOUR] = tm->tm_hour; + data[RTC_OFFSET_DOM] = tm->tm_mday; + data[RTC_OFFSET_DOW] = tm->tm_wday; + data[RTC_OFFSET_MTH] = tm->tm_mon; + data[RTC_OFFSET_YEAR] = tm->tm_year; + + mutex_lock(&rtc->lock); + ret = regmap_bulk_write(rtc->regmap, rtc->addr_base + RTC_TC_SEC, + data, RTC_OFFSET_COUNT); + if (ret < 0) + goto exit; + + /* Time register write to hardware after call trigger function */ + ret = mtk_rtc_write_trigger(rtc); + +exit: + mutex_unlock(&rtc->lock); + return ret; +} + +static int mtk_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + struct rtc_time *tm = &alm->time; + struct mt6397_rtc *rtc = dev_get_drvdata(dev); + u32 irqen, pdn2; + int ret; + u16 data[RTC_OFFSET_COUNT]; + + mutex_lock(&rtc->lock); + ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_EN, &irqen); + if (ret < 0) + goto err_exit; + ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_PDN2, &pdn2); + if (ret < 0) + goto err_exit; + + ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC, + data, RTC_OFFSET_COUNT); + if (ret < 0) + goto err_exit; + + alm->enabled = !!(irqen & RTC_IRQ_EN_AL); + alm->pending = !!(pdn2 & RTC_PDN2_PWRON_ALARM); + mutex_unlock(&rtc->lock); + + tm->tm_sec = data[RTC_OFFSET_SEC] & RTC_AL_SEC_MASK; + tm->tm_min = data[RTC_OFFSET_MIN] & RTC_AL_MIN_MASK; + tm->tm_hour = data[RTC_OFFSET_HOUR] & RTC_AL_HOU_MASK; + tm->tm_mday = data[RTC_OFFSET_DOM] & RTC_AL_DOM_MASK; + tm->tm_mon = data[RTC_OFFSET_MTH] & RTC_AL_MTH_MASK; + tm->tm_year = data[RTC_OFFSET_YEAR] & RTC_AL_YEA_MASK; + + tm->tm_mon--; + + return 0; +err_exit: + mutex_unlock(&rtc->lock); + return ret; +} + +static int mtk_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + struct rtc_time *tm = &alm->time; + struct mt6397_rtc *rtc = dev_get_drvdata(dev); + int ret; + u16 data[RTC_OFFSET_COUNT]; + + tm->tm_mon++; + + mutex_lock(&rtc->lock); + ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC, + data, RTC_OFFSET_COUNT); + if (ret < 0) + goto exit; + + data[RTC_OFFSET_SEC] = ((data[RTC_OFFSET_SEC] & ~(RTC_AL_SEC_MASK)) | + (tm->tm_sec & RTC_AL_SEC_MASK)); + data[RTC_OFFSET_MIN] = ((data[RTC_OFFSET_MIN] & ~(RTC_AL_MIN_MASK)) | + (tm->tm_min & RTC_AL_MIN_MASK)); + data[RTC_OFFSET_HOUR] = ((data[RTC_OFFSET_HOUR] & ~(RTC_AL_HOU_MASK)) | + (tm->tm_hour & RTC_AL_HOU_MASK)); + data[RTC_OFFSET_DOM] = ((data[RTC_OFFSET_DOM] & ~(RTC_AL_DOM_MASK)) | + (tm->tm_mday & RTC_AL_DOM_MASK)); + data[RTC_OFFSET_MTH] = ((data[RTC_OFFSET_MTH] & ~(RTC_AL_MTH_MASK)) | + (tm->tm_mon & RTC_AL_MTH_MASK)); + data[RTC_OFFSET_YEAR] = ((data[RTC_OFFSET_YEAR] & ~(RTC_AL_YEA_MASK)) | + (tm->tm_year & RTC_AL_YEA_MASK)); + + if (alm->enabled) { + ret = regmap_bulk_write(rtc->regmap, + rtc->addr_base + RTC_AL_SEC, + data, RTC_OFFSET_COUNT); + if (ret < 0) + goto exit; + ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_AL_MASK, + RTC_AL_MASK_DOW); + if (ret < 0) + goto exit; + ret = regmap_update_bits(rtc->regmap, + rtc->addr_base + RTC_IRQ_EN, + RTC_IRQ_EN_ONESHOT_AL, + RTC_IRQ_EN_ONESHOT_AL); + if (ret < 0) + goto exit; + } else { + ret = regmap_update_bits(rtc->regmap, + rtc->addr_base + RTC_IRQ_EN, + RTC_IRQ_EN_ONESHOT_AL, 0); + if (ret < 0) + goto exit; + } + + /* All alarm time register write to hardware after calling + * mtk_rtc_write_trigger. This can avoid race condition if alarm + * occur happen during writing alarm time register. + */ + ret = mtk_rtc_write_trigger(rtc); +exit: + mutex_unlock(&rtc->lock); + return ret; +} + +static const struct rtc_class_ops mtk_rtc_ops = { + .read_time = mtk_rtc_read_time, + .set_time = mtk_rtc_set_time, + .read_alarm = mtk_rtc_read_alarm, + .set_alarm = mtk_rtc_set_alarm, +}; + +static int mtk_rtc_probe(struct platform_device *pdev) +{ + struct resource *res; + struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent); + struct mt6397_rtc *rtc; + int ret; + + rtc = devm_kzalloc(&pdev->dev, sizeof(struct mt6397_rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -EINVAL; + rtc->addr_base = res->start; + + rtc->data = of_device_get_match_data(&pdev->dev); + + rtc->irq = platform_get_irq(pdev, 0); + if (rtc->irq < 0) + return rtc->irq; + + rtc->regmap = mt6397_chip->regmap; + mutex_init(&rtc->lock); + + platform_set_drvdata(pdev, rtc); + + rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc->rtc_dev)) + return PTR_ERR(rtc->rtc_dev); + + ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL, + mtk_rtc_irq_handler_thread, + IRQF_ONESHOT | IRQF_TRIGGER_HIGH, + "mt6397-rtc", rtc); + + if (ret) { + dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n", + rtc->irq, ret); + return ret; + } + + device_init_wakeup(&pdev->dev, true); + + rtc->rtc_dev->ops = &mtk_rtc_ops; + rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900; + rtc->rtc_dev->range_max = mktime64(2027, 12, 31, 23, 59, 59); + rtc->rtc_dev->start_secs = mktime64(1968, 1, 2, 0, 0, 0); + rtc->rtc_dev->set_start_time = true; + + return devm_rtc_register_device(rtc->rtc_dev); +} + +#ifdef CONFIG_PM_SLEEP +static int mt6397_rtc_suspend(struct device *dev) +{ + struct mt6397_rtc *rtc = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + enable_irq_wake(rtc->irq); + + return 0; +} + +static int mt6397_rtc_resume(struct device *dev) +{ + struct mt6397_rtc *rtc = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + disable_irq_wake(rtc->irq); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(mt6397_pm_ops, mt6397_rtc_suspend, + mt6397_rtc_resume); + +static const struct mtk_rtc_data mt6358_rtc_data = { + .wrtgr = RTC_WRTGR_MT6358, +}; + +static const struct mtk_rtc_data mt6397_rtc_data = { + .wrtgr = RTC_WRTGR_MT6397, +}; + +static const struct of_device_id mt6397_rtc_of_match[] = { + { .compatible = "mediatek,mt6323-rtc", .data = &mt6397_rtc_data }, + { .compatible = "mediatek,mt6357-rtc", .data = &mt6358_rtc_data }, + { .compatible = "mediatek,mt6358-rtc", .data = &mt6358_rtc_data }, + { .compatible = "mediatek,mt6397-rtc", .data = &mt6397_rtc_data }, + { } +}; +MODULE_DEVICE_TABLE(of, mt6397_rtc_of_match); + +static struct platform_driver mtk_rtc_driver = { + .driver = { + .name = "mt6397-rtc", + .of_match_table = mt6397_rtc_of_match, + .pm = &mt6397_pm_ops, + }, + .probe = mtk_rtc_probe, +}; + +module_platform_driver(mtk_rtc_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Tianping Fang "); +MODULE_DESCRIPTION("RTC Driver for MediaTek MT6397 PMIC"); -- cgit v1.3.1