ftrace: Synchronize the initialization of ftrace_opsgrafted

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 <rostedt@goodmis.org>

1 files changed, 340 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-88pm80x.c b/drivers/rtc/rtc-88pm80x.c
new file mode 100644
index 000000000..a3e52a5a7
--- /dev/null
+++ b/drivers/rtc/rtc-88pm80x.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Real Time Clock driver for Marvell 88PM80x PMIC
+ *
+ * Copyright (c) 2012 Marvell International Ltd.
+ *  Wenzeng Chen<wzch@marvell.com>
+ *  Qiao Zhou <zhouqiao@marvell.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/88pm80x.h>
+#include <linux/rtc.h>
+
+#define PM800_RTC_COUNTER1		(0xD1)
+#define PM800_RTC_COUNTER2		(0xD2)
+#define PM800_RTC_COUNTER3		(0xD3)
+#define PM800_RTC_COUNTER4		(0xD4)
+#define PM800_RTC_EXPIRE1_1		(0xD5)
+#define PM800_RTC_EXPIRE1_2		(0xD6)
+#define PM800_RTC_EXPIRE1_3		(0xD7)
+#define PM800_RTC_EXPIRE1_4		(0xD8)
+#define PM800_RTC_TRIM1			(0xD9)
+#define PM800_RTC_TRIM2			(0xDA)
+#define PM800_RTC_TRIM3			(0xDB)
+#define PM800_RTC_TRIM4			(0xDC)
+#define PM800_RTC_EXPIRE2_1		(0xDD)
+#define PM800_RTC_EXPIRE2_2		(0xDE)
+#define PM800_RTC_EXPIRE2_3		(0xDF)
+#define PM800_RTC_EXPIRE2_4		(0xE0)
+
+#define PM800_POWER_DOWN_LOG1	(0xE5)
+#define PM800_POWER_DOWN_LOG2	(0xE6)
+
+struct pm80x_rtc_info {
+	struct pm80x_chip *chip;
+	struct regmap *map;
+	struct rtc_device *rtc_dev;
+	struct device *dev;
+
+	int irq;
+};
+
+static irqreturn_t rtc_update_handler(int irq, void *data)
+{
+	struct pm80x_rtc_info *info = (struct pm80x_rtc_info *)data;
+	int mask;
+
+	mask = PM800_ALARM | PM800_ALARM_WAKEUP;
+	regmap_update_bits(info->map, PM800_RTC_CONTROL, mask | PM800_ALARM1_EN,
+			   mask);
+	rtc_update_irq(info->rtc_dev, 1, RTC_AF);
+	return IRQ_HANDLED;
+}
+
+static int pm80x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct pm80x_rtc_info *info = dev_get_drvdata(dev);
+
+	if (enabled)
+		regmap_update_bits(info->map, PM800_RTC_CONTROL,
+				   PM800_ALARM1_EN, PM800_ALARM1_EN);
+	else
+		regmap_update_bits(info->map, PM800_RTC_CONTROL,
+				   PM800_ALARM1_EN, 0);
+	return 0;
+}
+
+/*
+ * Calculate the next alarm time given the requested alarm time mask
+ * and the current time.
+ */
+static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
+				struct rtc_time *alrm)
+{
+	unsigned long next_time;
+	unsigned long now_time;
+
+	next->tm_year = now->tm_year;
+	next->tm_mon = now->tm_mon;
+	next->tm_mday = now->tm_mday;
+	next->tm_hour = alrm->tm_hour;
+	next->tm_min = alrm->tm_min;
+	next->tm_sec = alrm->tm_sec;
+
+	now_time = rtc_tm_to_time64(now);
+	next_time = rtc_tm_to_time64(next);
+
+	if (next_time < now_time) {
+		/* Advance one day */
+		next_time += 60 * 60 * 24;
+		rtc_time64_to_tm(next_time, next);
+	}
+}
+
+static int pm80x_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pm80x_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char buf[4];
+	unsigned long ticks, base, data;
+	regmap_raw_read(info->map, PM800_RTC_EXPIRE2_1, buf, 4);
+	base = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
+	dev_dbg(info->dev, "%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3]);
+
+	/* load 32-bit read-only counter */
+	regmap_raw_read(info->map, PM800_RTC_COUNTER1, buf, 4);
+	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
+	ticks = base + data;
+	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
+		base, data, ticks);
+	rtc_time64_to_tm(ticks, tm);
+	return 0;
+}
+
+static int pm80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pm80x_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char buf[4];
+	unsigned long ticks, base, data;
+
+	ticks = rtc_tm_to_time64(tm);
+
+	/* load 32-bit read-only counter */
+	regmap_raw_read(info->map, PM800_RTC_COUNTER1, buf, 4);
+	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
+	base = ticks - data;
+	dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
+		base, data, ticks);
+	buf[0] = base & 0xFF;
+	buf[1] = (base >> 8) & 0xFF;
+	buf[2] = (base >> 16) & 0xFF;
+	buf[3] = (base >> 24) & 0xFF;
+	regmap_raw_write(info->map, PM800_RTC_EXPIRE2_1, buf, 4);
+
+	return 0;
+}
+
+static int pm80x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct pm80x_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char buf[4];
+	unsigned long ticks, base, data;
+	int ret;
+
+	regmap_raw_read(info->map, PM800_RTC_EXPIRE2_1, buf, 4);
+	base = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
+	dev_dbg(info->dev, "%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3]);
+
+	regmap_raw_read(info->map, PM800_RTC_EXPIRE1_1, buf, 4);
+	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
+	ticks = base + data;
+	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
+		base, data, ticks);
+
+	rtc_time64_to_tm(ticks, &alrm->time);
+	regmap_read(info->map, PM800_RTC_CONTROL, &ret);
+	alrm->enabled = (ret & PM800_ALARM1_EN) ? 1 : 0;
+	alrm->pending = (ret & (PM800_ALARM | PM800_ALARM_WAKEUP)) ? 1 : 0;
+	return 0;
+}
+
+static int pm80x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct pm80x_rtc_info *info = dev_get_drvdata(dev);
+	struct rtc_time now_tm, alarm_tm;
+	unsigned long ticks, base, data;
+	unsigned char buf[4];
+	int mask;
+
+	regmap_update_bits(info->map, PM800_RTC_CONTROL, PM800_ALARM1_EN, 0);
+
+	regmap_raw_read(info->map, PM800_RTC_EXPIRE2_1, buf, 4);
+	base = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
+	dev_dbg(info->dev, "%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3]);
+
+	/* load 32-bit read-only counter */
+	regmap_raw_read(info->map, PM800_RTC_COUNTER1, buf, 4);
+	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
+	ticks = base + data;
+	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
+		base, data, ticks);
+
+	rtc_time64_to_tm(ticks, &now_tm);
+	dev_dbg(info->dev, "%s, now time : %lu\n", __func__, ticks);
+	rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
+	/* get new ticks for alarm in 24 hours */
+	ticks = rtc_tm_to_time64(&alarm_tm);
+	dev_dbg(info->dev, "%s, alarm time: %lu\n", __func__, ticks);
+	data = ticks - base;
+
+	buf[0] = data & 0xff;
+	buf[1] = (data >> 8) & 0xff;
+	buf[2] = (data >> 16) & 0xff;
+	buf[3] = (data >> 24) & 0xff;
+	regmap_raw_write(info->map, PM800_RTC_EXPIRE1_1, buf, 4);
+	if (alrm->enabled) {
+		mask = PM800_ALARM | PM800_ALARM_WAKEUP | PM800_ALARM1_EN;
+		regmap_update_bits(info->map, PM800_RTC_CONTROL, mask, mask);
+	} else {
+		mask = PM800_ALARM | PM800_ALARM_WAKEUP | PM800_ALARM1_EN;
+		regmap_update_bits(info->map, PM800_RTC_CONTROL, mask,
+				   PM800_ALARM | PM800_ALARM_WAKEUP);
+	}
+	return 0;
+}
+
+static const struct rtc_class_ops pm80x_rtc_ops = {
+	.read_time = pm80x_rtc_read_time,
+	.set_time = pm80x_rtc_set_time,
+	.read_alarm = pm80x_rtc_read_alarm,
+	.set_alarm = pm80x_rtc_set_alarm,
+	.alarm_irq_enable = pm80x_rtc_alarm_irq_enable,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int pm80x_rtc_suspend(struct device *dev)
+{
+	return pm80x_dev_suspend(dev);
+}
+
+static int pm80x_rtc_resume(struct device *dev)
+{
+	return pm80x_dev_resume(dev);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(pm80x_rtc_pm_ops, pm80x_rtc_suspend, pm80x_rtc_resume);
+
+static int pm80x_rtc_probe(struct platform_device *pdev)
+{
+	struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
+	struct pm80x_rtc_pdata *pdata = dev_get_platdata(&pdev->dev);
+	struct pm80x_rtc_info *info;
+	struct device_node *node = pdev->dev.of_node;
+	int ret;
+
+	if (!pdata && !node) {
+		dev_err(&pdev->dev,
+			"pm80x-rtc requires platform data or of_node\n");
+		return -EINVAL;
+	}
+
+	if (!pdata) {
+		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+		if (!pdata) {
+			dev_err(&pdev->dev, "failed to allocate memory\n");
+			return -ENOMEM;
+		}
+	}
+
+	info =
+	    devm_kzalloc(&pdev->dev, sizeof(struct pm80x_rtc_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	info->irq = platform_get_irq(pdev, 0);
+	if (info->irq < 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	info->chip = chip;
+	info->map = chip->regmap;
+	if (!info->map) {
+		dev_err(&pdev->dev, "no regmap!\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	info->dev = &pdev->dev;
+	dev_set_drvdata(&pdev->dev, info);
+
+	info->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(info->rtc_dev))
+		return PTR_ERR(info->rtc_dev);
+
+	ret = pm80x_request_irq(chip, info->irq, rtc_update_handler,
+				IRQF_ONESHOT, "rtc", info);
+	if (ret < 0) {
+		dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
+			info->irq, ret);
+		goto out;
+	}
+
+	info->rtc_dev->ops = &pm80x_rtc_ops;
+	info->rtc_dev->range_max = U32_MAX;
+
+	ret = devm_rtc_register_device(info->rtc_dev);
+	if (ret)
+		goto out_rtc;
+
+	/*
+	 * enable internal XO instead of internal 3.25MHz clock since it can
+	 * free running in PMIC power-down state.
+	 */
+	regmap_update_bits(info->map, PM800_RTC_CONTROL, PM800_RTC1_USE_XO,
+			   PM800_RTC1_USE_XO);
+
+	/* remember whether this power up is caused by PMIC RTC or not */
+	info->rtc_dev->dev.platform_data = &pdata->rtc_wakeup;
+
+	device_init_wakeup(&pdev->dev, true);
+
+	return 0;
+out_rtc:
+	pm80x_free_irq(chip, info->irq, info);
+out:
+	return ret;
+}
+
+static void pm80x_rtc_remove(struct platform_device *pdev)
+{
+	struct pm80x_rtc_info *info = platform_get_drvdata(pdev);
+	pm80x_free_irq(info->chip, info->irq, info);
+}
+
+static struct platform_driver pm80x_rtc_driver = {
+	.driver = {
+		   .name = "88pm80x-rtc",
+		   .pm = &pm80x_rtc_pm_ops,
+		   },
+	.probe = pm80x_rtc_probe,
+	.remove = pm80x_rtc_remove,
+};
+
+module_platform_driver(pm80x_rtc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Marvell 88PM80x RTC driver");
+MODULE_AUTHOR("Qiao Zhou <zhouqiao@marvell.com>");
+MODULE_ALIAS("platform:88pm80x-rtc");