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-nxp-bbnsm.c | 231 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 231 insertions(+) create mode 100644 drivers/rtc/rtc-nxp-bbnsm.c (limited to 'drivers/rtc/rtc-nxp-bbnsm.c') diff --git a/drivers/rtc/rtc-nxp-bbnsm.c b/drivers/rtc/rtc-nxp-bbnsm.c new file mode 100644 index 000000000..d4fc9dc58 --- /dev/null +++ b/drivers/rtc/rtc-nxp-bbnsm.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0+ +// +// Copyright 2022 NXP. + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define BBNSM_CTRL 0x8 +#define BBNSM_INT_EN 0x10 +#define BBNSM_EVENTS 0x14 +#define BBNSM_RTC_LS 0x40 +#define BBNSM_RTC_MS 0x44 +#define BBNSM_TA 0x50 + +#define RTC_EN 0x2 +#define RTC_EN_MSK 0x3 +#define TA_EN (0x2 << 2) +#define TA_DIS (0x1 << 2) +#define TA_EN_MSK (0x3 << 2) +#define RTC_INT_EN 0x2 +#define TA_INT_EN (0x2 << 2) + +#define BBNSM_EVENT_TA (0x2 << 2) + +#define CNTR_TO_SECS_SH 15 + +struct bbnsm_rtc { + struct rtc_device *rtc; + struct regmap *regmap; + int irq; + struct clk *clk; +}; + +static u32 bbnsm_read_counter(struct bbnsm_rtc *bbnsm) +{ + u32 rtc_msb, rtc_lsb; + unsigned int timeout = 100; + u32 time; + u32 tmp = 0; + + do { + time = tmp; + /* read the msb */ + regmap_read(bbnsm->regmap, BBNSM_RTC_MS, &rtc_msb); + /* read the lsb */ + regmap_read(bbnsm->regmap, BBNSM_RTC_LS, &rtc_lsb); + /* convert to seconds */ + tmp = (rtc_msb << 17) | (rtc_lsb >> 15); + } while (tmp != time && --timeout); + + return time; +} + +static int bbnsm_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev); + unsigned long time; + u32 val; + + regmap_read(bbnsm->regmap, BBNSM_CTRL, &val); + if ((val & RTC_EN_MSK) != RTC_EN) + return -EINVAL; + + time = bbnsm_read_counter(bbnsm); + rtc_time64_to_tm(time, tm); + + return 0; +} + +static int bbnsm_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev); + unsigned long time = rtc_tm_to_time64(tm); + + /* disable the RTC first */ + regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, 0); + + /* write the 32bit sec time to 47 bit timer counter, leaving 15 LSBs blank */ + regmap_write(bbnsm->regmap, BBNSM_RTC_LS, time << CNTR_TO_SECS_SH); + regmap_write(bbnsm->regmap, BBNSM_RTC_MS, time >> (32 - CNTR_TO_SECS_SH)); + + /* Enable the RTC again */ + regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, RTC_EN); + + return 0; +} + +static int bbnsm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev); + u32 bbnsm_events, bbnsm_ta; + + regmap_read(bbnsm->regmap, BBNSM_TA, &bbnsm_ta); + rtc_time64_to_tm(bbnsm_ta, &alrm->time); + + regmap_read(bbnsm->regmap, BBNSM_EVENTS, &bbnsm_events); + alrm->pending = (bbnsm_events & BBNSM_EVENT_TA) ? 1 : 0; + + return 0; +} + +static int bbnsm_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) +{ + struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev); + + /* enable the alarm event */ + regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, TA_EN_MSK, enable ? TA_EN : TA_DIS); + /* enable the alarm interrupt */ + regmap_update_bits(bbnsm->regmap, BBNSM_INT_EN, TA_EN_MSK, enable ? TA_EN : TA_DIS); + + return 0; +} + +static int bbnsm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev); + unsigned long time = rtc_tm_to_time64(&alrm->time); + + /* disable the alarm */ + regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, TA_EN, TA_EN); + + /* write the seconds to TA */ + regmap_write(bbnsm->regmap, BBNSM_TA, time); + + return bbnsm_rtc_alarm_irq_enable(dev, alrm->enabled); +} + +static const struct rtc_class_ops bbnsm_rtc_ops = { + .read_time = bbnsm_rtc_read_time, + .set_time = bbnsm_rtc_set_time, + .read_alarm = bbnsm_rtc_read_alarm, + .set_alarm = bbnsm_rtc_set_alarm, + .alarm_irq_enable = bbnsm_rtc_alarm_irq_enable, +}; + +static irqreturn_t bbnsm_rtc_irq_handler(int irq, void *dev_id) +{ + struct device *dev = dev_id; + struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev); + u32 val; + + regmap_read(bbnsm->regmap, BBNSM_EVENTS, &val); + if (val & BBNSM_EVENT_TA) { + bbnsm_rtc_alarm_irq_enable(dev, false); + /* clear the alarm event */ + regmap_write_bits(bbnsm->regmap, BBNSM_EVENTS, TA_EN_MSK, BBNSM_EVENT_TA); + rtc_update_irq(bbnsm->rtc, 1, RTC_AF | RTC_IRQF); + + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int bbnsm_rtc_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct bbnsm_rtc *bbnsm; + int ret; + + bbnsm = devm_kzalloc(&pdev->dev, sizeof(*bbnsm), GFP_KERNEL); + if (!bbnsm) + return -ENOMEM; + + bbnsm->rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(bbnsm->rtc)) + return PTR_ERR(bbnsm->rtc); + + bbnsm->regmap = syscon_node_to_regmap(np->parent); + if (IS_ERR(bbnsm->regmap)) { + dev_dbg(&pdev->dev, "bbnsm get regmap failed\n"); + return PTR_ERR(bbnsm->regmap); + } + + bbnsm->irq = platform_get_irq(pdev, 0); + if (bbnsm->irq < 0) + return bbnsm->irq; + + platform_set_drvdata(pdev, bbnsm); + + /* clear all the pending events */ + regmap_write(bbnsm->regmap, BBNSM_EVENTS, 0x7A); + + ret = devm_device_init_wakeup(&pdev->dev); + if (ret) + dev_err(&pdev->dev, "failed to init wakeup, %d\n", ret); + + ret = devm_pm_set_wake_irq(&pdev->dev, bbnsm->irq); + if (ret) + dev_err(&pdev->dev, "failed to set wake irq, %d\n", ret); + + ret = devm_request_irq(&pdev->dev, bbnsm->irq, bbnsm_rtc_irq_handler, + IRQF_SHARED, "rtc alarm", &pdev->dev); + if (ret) { + dev_err(&pdev->dev, "failed to request irq %d: %d\n", + bbnsm->irq, ret); + return ret; + } + + bbnsm->rtc->ops = &bbnsm_rtc_ops; + bbnsm->rtc->range_max = U32_MAX; + + return devm_rtc_register_device(bbnsm->rtc); +} + +static const struct of_device_id bbnsm_dt_ids[] = { + { .compatible = "nxp,imx93-bbnsm-rtc" }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, bbnsm_dt_ids); + +static struct platform_driver bbnsm_rtc_driver = { + .driver = { + .name = "bbnsm_rtc", + .of_match_table = bbnsm_dt_ids, + }, + .probe = bbnsm_rtc_probe, +}; +module_platform_driver(bbnsm_rtc_driver); + +MODULE_AUTHOR("Jacky Bai "); +MODULE_DESCRIPTION("NXP BBNSM RTC Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1