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, 325 insertions, 0 deletions

diff --git a/drivers/input/misc/palmas-pwrbutton.c b/drivers/input/misc/palmas-pwrbutton.c
new file mode 100644
index 000000000..f22083f44
--- /dev/null
+++ b/drivers/input/misc/palmas-pwrbutton.c
@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Texas Instruments' Palmas Power Button Input Driver
+ *
+ * Copyright (C) 2012-2014 Texas Instruments Incorporated - http://www.ti.com/
+ *	Girish S Ghongdemath
+ *	Nishanth Menon
+ */
+
+#include <linux/bitfield.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/palmas.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define PALMAS_LPK_TIME_MASK		0x0c
+#define PALMAS_PWRON_DEBOUNCE_MASK	0x03
+#define PALMAS_PWR_KEY_Q_TIME_MS	20
+
+/**
+ * struct palmas_pwron - Palmas power on data
+ * @palmas:		pointer to palmas device
+ * @input_dev:		pointer to input device
+ * @input_work:		work for detecting release of key
+ * @irq:		irq that we are hooked on to
+ */
+struct palmas_pwron {
+	struct palmas *palmas;
+	struct input_dev *input_dev;
+	struct delayed_work input_work;
+	int irq;
+};
+
+/**
+ * struct palmas_pwron_config - configuration of palmas power on
+ * @long_press_time_val:	value for long press h/w shutdown event
+ * @pwron_debounce_val:		value for debounce of power button
+ */
+struct palmas_pwron_config {
+	u8 long_press_time_val;
+	u8 pwron_debounce_val;
+};
+
+/**
+ * palmas_power_button_work() - Detects the button release event
+ * @work:	work item to detect button release
+ */
+static void palmas_power_button_work(struct work_struct *work)
+{
+	struct palmas_pwron *pwron = container_of(work,
+						  struct palmas_pwron,
+						  input_work.work);
+	struct input_dev *input_dev = pwron->input_dev;
+	unsigned int reg;
+	int error;
+
+	error = palmas_read(pwron->palmas, PALMAS_INTERRUPT_BASE,
+			    PALMAS_INT1_LINE_STATE, &reg);
+	if (error) {
+		dev_err(input_dev->dev.parent,
+			"Cannot read palmas PWRON status: %d\n", error);
+	} else if (reg & BIT(1)) {
+		/* The button is released, report event. */
+		input_report_key(input_dev, KEY_POWER, 0);
+		input_sync(input_dev);
+	} else {
+		/* The button is still depressed, keep checking. */
+		schedule_delayed_work(&pwron->input_work,
+				msecs_to_jiffies(PALMAS_PWR_KEY_Q_TIME_MS));
+	}
+}
+
+/**
+ * pwron_irq() - button press isr
+ * @irq:		irq
+ * @palmas_pwron:	pwron struct
+ *
+ * Return: IRQ_HANDLED
+ */
+static irqreturn_t pwron_irq(int irq, void *palmas_pwron)
+{
+	struct palmas_pwron *pwron = palmas_pwron;
+	struct input_dev *input_dev = pwron->input_dev;
+
+	input_report_key(input_dev, KEY_POWER, 1);
+	pm_wakeup_event(input_dev->dev.parent, 0);
+	input_sync(input_dev);
+
+	mod_delayed_work(system_dfl_wq, &pwron->input_work,
+			 msecs_to_jiffies(PALMAS_PWR_KEY_Q_TIME_MS));
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * palmas_pwron_params_ofinit() - device tree parameter parser
+ * @dev:	palmas button device
+ * @config:	configuration params that this fills up
+ */
+static void palmas_pwron_params_ofinit(struct device *dev,
+				       struct palmas_pwron_config *config)
+{
+	struct device_node *np;
+	u32 val;
+	int i, error;
+	static const u8 lpk_times[] = { 6, 8, 10, 12 };
+	static const int pwr_on_deb_ms[] = { 15, 100, 500, 1000 };
+
+	memset(config, 0, sizeof(*config));
+
+	/* Default config parameters */
+	config->long_press_time_val = ARRAY_SIZE(lpk_times) - 1;
+
+	np = dev->of_node;
+	if (!np)
+		return;
+
+	error = of_property_read_u32(np, "ti,palmas-long-press-seconds", &val);
+	if (!error) {
+		for (i = 0; i < ARRAY_SIZE(lpk_times); i++) {
+			if (val <= lpk_times[i]) {
+				config->long_press_time_val = i;
+				break;
+			}
+		}
+	}
+
+	error = of_property_read_u32(np,
+				     "ti,palmas-pwron-debounce-milli-seconds",
+				     &val);
+	if (!error) {
+		for (i = 0; i < ARRAY_SIZE(pwr_on_deb_ms); i++) {
+			if (val <= pwr_on_deb_ms[i]) {
+				config->pwron_debounce_val = i;
+				break;
+			}
+		}
+	}
+
+	dev_info(dev, "h/w controlled shutdown duration=%d seconds\n",
+		 lpk_times[config->long_press_time_val]);
+}
+
+/**
+ * palmas_pwron_probe() - probe
+ * @pdev:	platform device for the button
+ *
+ * Return: 0 for successful probe else appropriate error
+ */
+static int palmas_pwron_probe(struct platform_device *pdev)
+{
+	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct input_dev *input_dev;
+	struct palmas_pwron *pwron;
+	struct palmas_pwron_config config;
+	int val;
+	int error;
+
+	palmas_pwron_params_ofinit(dev, &config);
+
+	pwron = kzalloc_obj(*pwron);
+	if (!pwron)
+		return -ENOMEM;
+
+	input_dev = input_allocate_device();
+	if (!input_dev) {
+		dev_err(dev, "Can't allocate power button\n");
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	input_dev->name = "palmas_pwron";
+	input_dev->phys = "palmas_pwron/input0";
+	input_dev->dev.parent = dev;
+
+	input_set_capability(input_dev, EV_KEY, KEY_POWER);
+
+	/*
+	 * Setup default hardware shutdown option (long key press)
+	 * and debounce.
+	 */
+	val = FIELD_PREP(PALMAS_LPK_TIME_MASK, config.long_press_time_val) |
+	      FIELD_PREP(PALMAS_PWRON_DEBOUNCE_MASK, config.pwron_debounce_val);
+	error = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
+				   PALMAS_LONG_PRESS_KEY,
+				   PALMAS_LPK_TIME_MASK |
+					PALMAS_PWRON_DEBOUNCE_MASK,
+				   val);
+	if (error) {
+		dev_err(dev, "LONG_PRESS_KEY_UPDATE failed: %d\n", error);
+		goto err_free_input;
+	}
+
+	pwron->palmas = palmas;
+	pwron->input_dev = input_dev;
+
+	INIT_DELAYED_WORK(&pwron->input_work, palmas_power_button_work);
+
+	pwron->irq = platform_get_irq(pdev, 0);
+	if (pwron->irq < 0) {
+		error = pwron->irq;
+		goto err_free_input;
+	}
+
+	error = request_threaded_irq(pwron->irq, NULL, pwron_irq,
+				     IRQF_TRIGGER_HIGH |
+					IRQF_TRIGGER_LOW |
+					IRQF_ONESHOT,
+				     dev_name(dev), pwron);
+	if (error) {
+		dev_err(dev, "Can't get IRQ for pwron: %d\n", error);
+		goto err_free_input;
+	}
+
+	error = input_register_device(input_dev);
+	if (error) {
+		dev_err(dev, "Can't register power button: %d\n", error);
+		goto err_free_irq;
+	}
+
+	platform_set_drvdata(pdev, pwron);
+	device_init_wakeup(dev, true);
+
+	return 0;
+
+err_free_irq:
+	cancel_delayed_work_sync(&pwron->input_work);
+	free_irq(pwron->irq, pwron);
+err_free_input:
+	input_free_device(input_dev);
+err_free_mem:
+	kfree(pwron);
+	return error;
+}
+
+/**
+ * palmas_pwron_remove() - Cleanup on removal
+ * @pdev:	platform device for the button
+ *
+ * Return: 0
+ */
+static void palmas_pwron_remove(struct platform_device *pdev)
+{
+	struct palmas_pwron *pwron = platform_get_drvdata(pdev);
+
+	free_irq(pwron->irq, pwron);
+	cancel_delayed_work_sync(&pwron->input_work);
+
+	input_unregister_device(pwron->input_dev);
+	kfree(pwron);
+}
+
+/**
+ * palmas_pwron_suspend() - suspend handler
+ * @dev:	power button device
+ *
+ * Cancel all pending work items for the power button, setup irq for wakeup
+ *
+ * Return: 0
+ */
+static int palmas_pwron_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct palmas_pwron *pwron = platform_get_drvdata(pdev);
+
+	cancel_delayed_work_sync(&pwron->input_work);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(pwron->irq);
+
+	return 0;
+}
+
+/**
+ * palmas_pwron_resume() - resume handler
+ * @dev:	power button device
+ *
+ * Just disable the wakeup capability of irq here.
+ *
+ * Return: 0
+ */
+static int palmas_pwron_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct palmas_pwron *pwron = platform_get_drvdata(pdev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(pwron->irq);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(palmas_pwron_pm,
+				palmas_pwron_suspend, palmas_pwron_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_palmas_pwr_match[] = {
+	{ .compatible = "ti,palmas-pwrbutton" },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, of_palmas_pwr_match);
+#endif
+
+static struct platform_driver palmas_pwron_driver = {
+	.probe	= palmas_pwron_probe,
+	.remove	= palmas_pwron_remove,
+	.driver	= {
+		.name	= "palmas_pwrbutton",
+		.of_match_table = of_match_ptr(of_palmas_pwr_match),
+		.pm	= pm_sleep_ptr(&palmas_pwron_pm),
+	},
+};
+module_platform_driver(palmas_pwron_driver);
+
+MODULE_ALIAS("platform:palmas-pwrbutton");
+MODULE_DESCRIPTION("Palmas Power Button");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Texas Instruments Inc.");