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-rc5t583.c | 312 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 312 insertions(+) create mode 100644 drivers/rtc/rtc-rc5t583.c (limited to 'drivers/rtc/rtc-rc5t583.c') diff --git a/drivers/rtc/rtc-rc5t583.c b/drivers/rtc/rtc-rc5t583.c new file mode 100644 index 000000000..8ba9cda74 --- /dev/null +++ b/drivers/rtc/rtc-rc5t583.c @@ -0,0 +1,312 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * rtc-rc5t583.c -- RICOH RC5T583 Real Time Clock + * + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. + * Author: Venu Byravarasu + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct rc5t583_rtc { + struct rtc_device *rtc; + /* To store the list of enabled interrupts, during system suspend */ + u32 irqen; +}; + +/* Total number of RTC registers needed to set time*/ +#define NUM_TIME_REGS (RC5T583_RTC_YEAR - RC5T583_RTC_SEC + 1) + +/* Total number of RTC registers needed to set Y-Alarm*/ +#define NUM_YAL_REGS (RC5T583_RTC_AY_YEAR - RC5T583_RTC_AY_MIN + 1) + +/* Set Y-Alarm interrupt */ +#define SET_YAL BIT(5) + +/* Get Y-Alarm interrupt status*/ +#define GET_YAL_STATUS BIT(3) + +static int rc5t583_rtc_alarm_irq_enable(struct device *dev, unsigned enabled) +{ + struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent); + u8 val; + + /* Set Y-Alarm, based on 'enabled' */ + val = enabled ? SET_YAL : 0; + + return regmap_update_bits(rc5t583->regmap, RC5T583_RTC_CTL1, SET_YAL, + val); +} + +/* + * Gets current rc5t583 RTC time and date parameters. + * + * The RTC's time/alarm representation is not what gmtime(3) requires + * Linux to use: + * + * - Months are 1..12 vs Linux 0-11 + * - Years are 0..99 vs Linux 1900..N (we assume 21st century) + */ +static int rc5t583_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent); + u8 rtc_data[NUM_TIME_REGS]; + int ret; + + ret = regmap_bulk_read(rc5t583->regmap, RC5T583_RTC_SEC, rtc_data, + NUM_TIME_REGS); + if (ret < 0) { + dev_err(dev, "RTC read time failed with err:%d\n", ret); + return ret; + } + + tm->tm_sec = bcd2bin(rtc_data[0]); + tm->tm_min = bcd2bin(rtc_data[1]); + tm->tm_hour = bcd2bin(rtc_data[2]); + tm->tm_wday = bcd2bin(rtc_data[3]); + tm->tm_mday = bcd2bin(rtc_data[4]); + tm->tm_mon = bcd2bin(rtc_data[5]) - 1; + tm->tm_year = bcd2bin(rtc_data[6]) + 100; + + return ret; +} + +static int rc5t583_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent); + unsigned char rtc_data[NUM_TIME_REGS]; + int ret; + + rtc_data[0] = bin2bcd(tm->tm_sec); + rtc_data[1] = bin2bcd(tm->tm_min); + rtc_data[2] = bin2bcd(tm->tm_hour); + rtc_data[3] = bin2bcd(tm->tm_wday); + rtc_data[4] = bin2bcd(tm->tm_mday); + rtc_data[5] = bin2bcd(tm->tm_mon + 1); + rtc_data[6] = bin2bcd(tm->tm_year - 100); + + ret = regmap_bulk_write(rc5t583->regmap, RC5T583_RTC_SEC, rtc_data, + NUM_TIME_REGS); + if (ret < 0) { + dev_err(dev, "RTC set time failed with error %d\n", ret); + return ret; + } + + return ret; +} + +static int rc5t583_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent); + unsigned char alarm_data[NUM_YAL_REGS]; + u32 interrupt_enable; + int ret; + + ret = regmap_bulk_read(rc5t583->regmap, RC5T583_RTC_AY_MIN, alarm_data, + NUM_YAL_REGS); + if (ret < 0) { + dev_err(dev, "rtc_read_alarm error %d\n", ret); + return ret; + } + + alm->time.tm_sec = 0; + alm->time.tm_min = bcd2bin(alarm_data[0]); + alm->time.tm_hour = bcd2bin(alarm_data[1]); + alm->time.tm_mday = bcd2bin(alarm_data[2]); + alm->time.tm_mon = bcd2bin(alarm_data[3]) - 1; + alm->time.tm_year = bcd2bin(alarm_data[4]) + 100; + + ret = regmap_read(rc5t583->regmap, RC5T583_RTC_CTL1, &interrupt_enable); + if (ret < 0) + return ret; + + /* check if YALE is set */ + if (interrupt_enable & SET_YAL) + alm->enabled = 1; + + return ret; +} + +static int rc5t583_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent); + unsigned char alarm_data[NUM_YAL_REGS]; + int ret; + + ret = rc5t583_rtc_alarm_irq_enable(dev, 0); + if (ret) + return ret; + + alarm_data[0] = bin2bcd(alm->time.tm_min); + alarm_data[1] = bin2bcd(alm->time.tm_hour); + alarm_data[2] = bin2bcd(alm->time.tm_mday); + alarm_data[3] = bin2bcd(alm->time.tm_mon + 1); + alarm_data[4] = bin2bcd(alm->time.tm_year - 100); + + ret = regmap_bulk_write(rc5t583->regmap, RC5T583_RTC_AY_MIN, alarm_data, + NUM_YAL_REGS); + if (ret) { + dev_err(dev, "rtc_set_alarm error %d\n", ret); + return ret; + } + + if (alm->enabled) + ret = rc5t583_rtc_alarm_irq_enable(dev, 1); + + return ret; +} + +static irqreturn_t rc5t583_rtc_interrupt(int irq, void *rtc) +{ + struct device *dev = rtc; + struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent); + struct rc5t583_rtc *rc5t583_rtc = dev_get_drvdata(dev); + unsigned long events = 0; + int ret; + u32 rtc_reg; + + ret = regmap_read(rc5t583->regmap, RC5T583_RTC_CTL2, &rtc_reg); + if (ret < 0) + return IRQ_NONE; + + if (rtc_reg & GET_YAL_STATUS) { + events = RTC_IRQF | RTC_AF; + /* clear pending Y-alarm interrupt bit */ + rtc_reg &= ~GET_YAL_STATUS; + } + + ret = regmap_write(rc5t583->regmap, RC5T583_RTC_CTL2, rtc_reg); + if (ret) + return IRQ_NONE; + + /* Notify RTC core on event */ + rtc_update_irq(rc5t583_rtc->rtc, 1, events); + + return IRQ_HANDLED; +} + +static const struct rtc_class_ops rc5t583_rtc_ops = { + .read_time = rc5t583_rtc_read_time, + .set_time = rc5t583_rtc_set_time, + .read_alarm = rc5t583_rtc_read_alarm, + .set_alarm = rc5t583_rtc_set_alarm, + .alarm_irq_enable = rc5t583_rtc_alarm_irq_enable, +}; + +static int rc5t583_rtc_probe(struct platform_device *pdev) +{ + struct rc5t583 *rc5t583 = dev_get_drvdata(pdev->dev.parent); + struct rc5t583_rtc *ricoh_rtc; + struct rc5t583_platform_data *pmic_plat_data; + int ret; + int irq; + + ricoh_rtc = devm_kzalloc(&pdev->dev, sizeof(struct rc5t583_rtc), + GFP_KERNEL); + if (!ricoh_rtc) + return -ENOMEM; + + platform_set_drvdata(pdev, ricoh_rtc); + + /* Clear pending interrupts */ + ret = regmap_write(rc5t583->regmap, RC5T583_RTC_CTL2, 0); + if (ret < 0) + return ret; + + /* clear RTC Adjust register */ + ret = regmap_write(rc5t583->regmap, RC5T583_RTC_ADJ, 0); + if (ret < 0) { + dev_err(&pdev->dev, "unable to program rtc_adjust reg\n"); + return -EBUSY; + } + + pmic_plat_data = dev_get_platdata(rc5t583->dev); + irq = pmic_plat_data->irq_base; + if (irq <= 0) { + dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n", + irq); + return ret; + } + + irq += RC5T583_IRQ_YALE; + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, + rc5t583_rtc_interrupt, IRQF_TRIGGER_LOW, + "rtc-rc5t583", &pdev->dev); + if (ret < 0) { + dev_err(&pdev->dev, "IRQ is not free.\n"); + return ret; + } + device_init_wakeup(&pdev->dev, true); + + ricoh_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, + &rc5t583_rtc_ops, THIS_MODULE); + if (IS_ERR(ricoh_rtc->rtc)) { + ret = PTR_ERR(ricoh_rtc->rtc); + dev_err(&pdev->dev, "RTC device register: err %d\n", ret); + return ret; + } + + return 0; +} + +/* + * Disable rc5t583 RTC interrupts. + * Sets status flag to free. + */ +static void rc5t583_rtc_remove(struct platform_device *pdev) +{ + struct rc5t583_rtc *rc5t583_rtc = platform_get_drvdata(pdev); + + rc5t583_rtc_alarm_irq_enable(&rc5t583_rtc->rtc->dev, 0); +} + +#ifdef CONFIG_PM_SLEEP +static int rc5t583_rtc_suspend(struct device *dev) +{ + struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent); + struct rc5t583_rtc *rc5t583_rtc = dev_get_drvdata(dev); + int ret; + + /* Store current list of enabled interrupts*/ + ret = regmap_read(rc5t583->regmap, RC5T583_RTC_CTL1, + &rc5t583_rtc->irqen); + return ret; +} + +static int rc5t583_rtc_resume(struct device *dev) +{ + struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent); + struct rc5t583_rtc *rc5t583_rtc = dev_get_drvdata(dev); + + /* Restore list of enabled interrupts before suspend */ + return regmap_write(rc5t583->regmap, RC5T583_RTC_CTL1, + rc5t583_rtc->irqen); +} +#endif + +static SIMPLE_DEV_PM_OPS(rc5t583_rtc_pm_ops, rc5t583_rtc_suspend, + rc5t583_rtc_resume); + +static struct platform_driver rc5t583_rtc_driver = { + .probe = rc5t583_rtc_probe, + .remove = rc5t583_rtc_remove, + .driver = { + .name = "rtc-rc5t583", + .pm = &rc5t583_rtc_pm_ops, + }, +}; + +module_platform_driver(rc5t583_rtc_driver); +MODULE_ALIAS("platform:rtc-rc5t583"); +MODULE_AUTHOR("Venu Byravarasu "); +MODULE_DESCRIPTION("RICOH 5T583 RTC driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1