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-as3722.c | 252 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 252 insertions(+) create mode 100644 drivers/rtc/rtc-as3722.c (limited to 'drivers/rtc/rtc-as3722.c') diff --git a/drivers/rtc/rtc-as3722.c b/drivers/rtc/rtc-as3722.c new file mode 100644 index 000000000..9682d6457 --- /dev/null +++ b/drivers/rtc/rtc-as3722.c @@ -0,0 +1,252 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * rtc-as3722.c - Real Time Clock driver for ams AS3722 PMICs + * + * Copyright (C) 2013 ams AG + * Copyright (c) 2013, NVIDIA Corporation. All rights reserved. + * + * Author: Florian Lobmaier + * Author: Laxman Dewangan + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define AS3722_RTC_START_YEAR 2000 +struct as3722_rtc { + struct rtc_device *rtc; + struct device *dev; + struct as3722 *as3722; + int alarm_irq; + bool irq_enable; +}; + +static void as3722_time_to_reg(u8 *rbuff, struct rtc_time *tm) +{ + rbuff[0] = bin2bcd(tm->tm_sec); + rbuff[1] = bin2bcd(tm->tm_min); + rbuff[2] = bin2bcd(tm->tm_hour); + rbuff[3] = bin2bcd(tm->tm_mday); + rbuff[4] = bin2bcd(tm->tm_mon + 1); + rbuff[5] = bin2bcd(tm->tm_year - (AS3722_RTC_START_YEAR - 1900)); +} + +static void as3722_reg_to_time(u8 *rbuff, struct rtc_time *tm) +{ + tm->tm_sec = bcd2bin(rbuff[0] & 0x7F); + tm->tm_min = bcd2bin(rbuff[1] & 0x7F); + tm->tm_hour = bcd2bin(rbuff[2] & 0x3F); + tm->tm_mday = bcd2bin(rbuff[3] & 0x3F); + tm->tm_mon = bcd2bin(rbuff[4] & 0x1F) - 1; + tm->tm_year = (AS3722_RTC_START_YEAR - 1900) + bcd2bin(rbuff[5] & 0x7F); + return; +} + +static int as3722_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev); + struct as3722 *as3722 = as3722_rtc->as3722; + u8 as_time_array[6]; + int ret; + + ret = as3722_block_read(as3722, AS3722_RTC_SECOND_REG, + 6, as_time_array); + if (ret < 0) { + dev_err(dev, "RTC_SECOND reg block read failed %d\n", ret); + return ret; + } + as3722_reg_to_time(as_time_array, tm); + return 0; +} + +static int as3722_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev); + struct as3722 *as3722 = as3722_rtc->as3722; + u8 as_time_array[6]; + int ret; + + if (tm->tm_year < (AS3722_RTC_START_YEAR - 1900)) + return -EINVAL; + + as3722_time_to_reg(as_time_array, tm); + ret = as3722_block_write(as3722, AS3722_RTC_SECOND_REG, 6, + as_time_array); + if (ret < 0) + dev_err(dev, "RTC_SECOND reg block write failed %d\n", ret); + return ret; +} + +static int as3722_rtc_alarm_irq_enable(struct device *dev, + unsigned int enabled) +{ + struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev); + + if (enabled && !as3722_rtc->irq_enable) { + enable_irq(as3722_rtc->alarm_irq); + as3722_rtc->irq_enable = true; + } else if (!enabled && as3722_rtc->irq_enable) { + disable_irq(as3722_rtc->alarm_irq); + as3722_rtc->irq_enable = false; + } + return 0; +} + +static int as3722_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev); + struct as3722 *as3722 = as3722_rtc->as3722; + u8 as_time_array[6]; + int ret; + + ret = as3722_block_read(as3722, AS3722_RTC_ALARM_SECOND_REG, 6, + as_time_array); + if (ret < 0) { + dev_err(dev, "RTC_ALARM_SECOND block read failed %d\n", ret); + return ret; + } + + as3722_reg_to_time(as_time_array, &alrm->time); + return 0; +} + +static int as3722_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev); + struct as3722 *as3722 = as3722_rtc->as3722; + u8 as_time_array[6]; + int ret; + + if (alrm->time.tm_year < (AS3722_RTC_START_YEAR - 1900)) + return -EINVAL; + + ret = as3722_rtc_alarm_irq_enable(dev, 0); + if (ret < 0) { + dev_err(dev, "Disable RTC alarm failed\n"); + return ret; + } + + as3722_time_to_reg(as_time_array, &alrm->time); + ret = as3722_block_write(as3722, AS3722_RTC_ALARM_SECOND_REG, 6, + as_time_array); + if (ret < 0) { + dev_err(dev, "RTC_ALARM_SECOND block write failed %d\n", ret); + return ret; + } + + if (alrm->enabled) + ret = as3722_rtc_alarm_irq_enable(dev, alrm->enabled); + return ret; +} + +static irqreturn_t as3722_alarm_irq(int irq, void *data) +{ + struct as3722_rtc *as3722_rtc = data; + + rtc_update_irq(as3722_rtc->rtc, 1, RTC_IRQF | RTC_AF); + return IRQ_HANDLED; +} + +static const struct rtc_class_ops as3722_rtc_ops = { + .read_time = as3722_rtc_read_time, + .set_time = as3722_rtc_set_time, + .read_alarm = as3722_rtc_read_alarm, + .set_alarm = as3722_rtc_set_alarm, + .alarm_irq_enable = as3722_rtc_alarm_irq_enable, +}; + +static int as3722_rtc_probe(struct platform_device *pdev) +{ + struct as3722 *as3722 = dev_get_drvdata(pdev->dev.parent); + struct as3722_rtc *as3722_rtc; + int ret; + + as3722_rtc = devm_kzalloc(&pdev->dev, sizeof(*as3722_rtc), GFP_KERNEL); + if (!as3722_rtc) + return -ENOMEM; + + as3722_rtc->as3722 = as3722; + as3722_rtc->dev = &pdev->dev; + platform_set_drvdata(pdev, as3722_rtc); + + /* Enable the RTC to make sure it is running. */ + ret = as3722_update_bits(as3722, AS3722_RTC_CONTROL_REG, + AS3722_RTC_ON | AS3722_RTC_ALARM_WAKEUP_EN, + AS3722_RTC_ON | AS3722_RTC_ALARM_WAKEUP_EN); + if (ret < 0) { + dev_err(&pdev->dev, "RTC_CONTROL reg write failed: %d\n", ret); + return ret; + } + + device_init_wakeup(&pdev->dev, true); + + as3722_rtc->rtc = devm_rtc_device_register(&pdev->dev, "as3722-rtc", + &as3722_rtc_ops, THIS_MODULE); + if (IS_ERR(as3722_rtc->rtc)) { + ret = PTR_ERR(as3722_rtc->rtc); + dev_err(&pdev->dev, "RTC register failed: %d\n", ret); + return ret; + } + + as3722_rtc->alarm_irq = platform_get_irq(pdev, 0); + dev_info(&pdev->dev, "RTC interrupt %d\n", as3722_rtc->alarm_irq); + + ret = devm_request_threaded_irq(&pdev->dev, as3722_rtc->alarm_irq, NULL, + as3722_alarm_irq, IRQF_ONESHOT, + "rtc-alarm", as3722_rtc); + if (ret < 0) { + dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n", + as3722_rtc->alarm_irq, ret); + return ret; + } + disable_irq(as3722_rtc->alarm_irq); + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int as3722_rtc_suspend(struct device *dev) +{ + struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + enable_irq_wake(as3722_rtc->alarm_irq); + + return 0; +} + +static int as3722_rtc_resume(struct device *dev) +{ + struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + disable_irq_wake(as3722_rtc->alarm_irq); + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(as3722_rtc_pm_ops, as3722_rtc_suspend, + as3722_rtc_resume); + +static struct platform_driver as3722_rtc_driver = { + .probe = as3722_rtc_probe, + .driver = { + .name = "as3722-rtc", + .pm = &as3722_rtc_pm_ops, + }, +}; +module_platform_driver(as3722_rtc_driver); + +MODULE_DESCRIPTION("RTC driver for AS3722 PMICs"); +MODULE_ALIAS("platform:as3722-rtc"); +MODULE_AUTHOR("Florian Lobmaier "); +MODULE_AUTHOR("Laxman Dewangan "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1