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, 305 insertions, 0 deletions

diff --git a/drivers/input/misc/atc260x-onkey.c b/drivers/input/misc/atc260x-onkey.c
new file mode 100644
index 000000000..999aabf9d
--- /dev/null
+++ b/drivers/input/misc/atc260x-onkey.c
@@ -0,0 +1,305 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Onkey driver for Actions Semi ATC260x PMICs.
+ *
+ * Copyright (c) 2020 Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/atc260x/core.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* <2s for short press, >2s for long press */
+#define KEY_PRESS_TIME_SEC	2
+
+/* Driver internals */
+enum atc260x_onkey_reset_status {
+	KEY_RESET_HW_DEFAULT,
+	KEY_RESET_DISABLED,
+	KEY_RESET_USER_SEL,
+};
+
+struct atc260x_onkey_params {
+	u32 reg_int_ctl;
+	u32 kdwn_state_bm;
+	u32 long_int_pnd_bm;
+	u32 short_int_pnd_bm;
+	u32 kdwn_int_pnd_bm;
+	u32 press_int_en_bm;
+	u32 kdwn_int_en_bm;
+	u32 press_time_bm;
+	u32 reset_en_bm;
+	u32 reset_time_bm;
+};
+
+struct atc260x_onkey {
+	struct atc260x *atc260x;
+	const struct atc260x_onkey_params *params;
+	struct input_dev *input_dev;
+	struct delayed_work work;
+	int irq;
+};
+
+static const struct atc260x_onkey_params atc2603c_onkey_params = {
+	.reg_int_ctl		= ATC2603C_PMU_SYS_CTL2,
+	.long_int_pnd_bm	= ATC2603C_PMU_SYS_CTL2_ONOFF_LONG_PRESS,
+	.short_int_pnd_bm	= ATC2603C_PMU_SYS_CTL2_ONOFF_SHORT_PRESS,
+	.kdwn_int_pnd_bm	= ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_PD,
+	.press_int_en_bm	= ATC2603C_PMU_SYS_CTL2_ONOFF_INT_EN,
+	.kdwn_int_en_bm		= ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_INT_EN,
+	.kdwn_state_bm		= ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS,
+	.press_time_bm		= ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_TIME,
+	.reset_en_bm		= ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_RESET_EN,
+	.reset_time_bm		= ATC2603C_PMU_SYS_CTL2_ONOFF_RESET_TIME_SEL,
+};
+
+static const struct atc260x_onkey_params atc2609a_onkey_params = {
+	.reg_int_ctl		= ATC2609A_PMU_SYS_CTL2,
+	.long_int_pnd_bm	= ATC2609A_PMU_SYS_CTL2_ONOFF_LONG_PRESS,
+	.short_int_pnd_bm	= ATC2609A_PMU_SYS_CTL2_ONOFF_SHORT_PRESS,
+	.kdwn_int_pnd_bm	= ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS_PD,
+	.press_int_en_bm	= ATC2609A_PMU_SYS_CTL2_ONOFF_LSP_INT_EN,
+	.kdwn_int_en_bm		= ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS_INT_EN,
+	.kdwn_state_bm		= ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS,
+	.press_time_bm		= ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS_TIME,
+	.reset_en_bm		= ATC2609A_PMU_SYS_CTL2_ONOFF_RESET_EN,
+	.reset_time_bm		= ATC2609A_PMU_SYS_CTL2_ONOFF_RESET_TIME_SEL,
+};
+
+static int atc2603x_onkey_hw_init(struct atc260x_onkey *onkey,
+				  enum atc260x_onkey_reset_status reset_status,
+				  u32 reset_time, u32 press_time)
+{
+	u32 reg_bm, reg_val;
+
+	reg_bm = onkey->params->long_int_pnd_bm |
+		 onkey->params->short_int_pnd_bm |
+		 onkey->params->kdwn_int_pnd_bm |
+		 onkey->params->press_int_en_bm |
+		 onkey->params->kdwn_int_en_bm;
+
+	reg_val = reg_bm | press_time;
+	reg_bm |= onkey->params->press_time_bm;
+
+	if (reset_status == KEY_RESET_DISABLED) {
+		reg_bm |= onkey->params->reset_en_bm;
+	} else if (reset_status == KEY_RESET_USER_SEL) {
+		reg_bm |= onkey->params->reset_en_bm |
+			  onkey->params->reset_time_bm;
+		reg_val |= onkey->params->reset_en_bm | reset_time;
+	}
+
+	return regmap_update_bits(onkey->atc260x->regmap,
+				  onkey->params->reg_int_ctl, reg_bm, reg_val);
+}
+
+static void atc260x_onkey_query(struct atc260x_onkey *onkey)
+{
+	u32 reg_bits;
+	int ret, key_down;
+
+	ret = regmap_read(onkey->atc260x->regmap,
+			  onkey->params->reg_int_ctl, &key_down);
+	if (ret) {
+		key_down = 1;
+		dev_err(onkey->atc260x->dev,
+			"Failed to read onkey status: %d\n", ret);
+	} else {
+		key_down &= onkey->params->kdwn_state_bm;
+	}
+
+	/*
+	 * The hardware generates interrupt only when the onkey pin is
+	 * asserted. Hence, the deassertion of the pin is simulated through
+	 * work queue.
+	 */
+	if (key_down) {
+		schedule_delayed_work(&onkey->work, msecs_to_jiffies(200));
+		return;
+	}
+
+	/*
+	 * The key-down status bit is cleared when the On/Off button
+	 * is released.
+	 */
+	input_report_key(onkey->input_dev, KEY_POWER, 0);
+	input_sync(onkey->input_dev);
+
+	reg_bits = onkey->params->long_int_pnd_bm |
+		   onkey->params->short_int_pnd_bm |
+		   onkey->params->kdwn_int_pnd_bm |
+		   onkey->params->press_int_en_bm |
+		   onkey->params->kdwn_int_en_bm;
+
+	/* Clear key press pending events and enable key press interrupts. */
+	regmap_update_bits(onkey->atc260x->regmap, onkey->params->reg_int_ctl,
+			   reg_bits, reg_bits);
+}
+
+static void atc260x_onkey_work(struct work_struct *work)
+{
+	struct atc260x_onkey *onkey = container_of(work, struct atc260x_onkey,
+						   work.work);
+	atc260x_onkey_query(onkey);
+}
+
+static irqreturn_t atc260x_onkey_irq(int irq, void *data)
+{
+	struct atc260x_onkey *onkey = data;
+	int ret;
+
+	/* Disable key press interrupts. */
+	ret = regmap_update_bits(onkey->atc260x->regmap,
+				 onkey->params->reg_int_ctl,
+				 onkey->params->press_int_en_bm |
+				 onkey->params->kdwn_int_en_bm, 0);
+	if (ret)
+		dev_err(onkey->atc260x->dev,
+			"Failed to disable interrupts: %d\n", ret);
+
+	input_report_key(onkey->input_dev, KEY_POWER, 1);
+	input_sync(onkey->input_dev);
+
+	atc260x_onkey_query(onkey);
+
+	return IRQ_HANDLED;
+}
+
+static int atc260x_onkey_open(struct input_dev *dev)
+{
+	struct atc260x_onkey *onkey = input_get_drvdata(dev);
+
+	enable_irq(onkey->irq);
+
+	return 0;
+}
+
+static void atc260x_onkey_close(struct input_dev *dev)
+{
+	struct atc260x_onkey *onkey = input_get_drvdata(dev);
+
+	disable_irq(onkey->irq);
+	cancel_delayed_work_sync(&onkey->work);
+}
+
+static int atc260x_onkey_probe(struct platform_device *pdev)
+{
+	struct atc260x *atc260x = dev_get_drvdata(pdev->dev.parent);
+	struct atc260x_onkey *onkey;
+	struct input_dev *input_dev;
+	enum atc260x_onkey_reset_status reset_status;
+	u32 press_time = KEY_PRESS_TIME_SEC, reset_time = 0;
+	int val, error;
+
+	onkey = devm_kzalloc(&pdev->dev, sizeof(*onkey), GFP_KERNEL);
+	if (!onkey)
+		return -ENOMEM;
+
+	error = device_property_read_u32(pdev->dev.parent,
+					 "reset-time-sec", &val);
+	if (error) {
+		reset_status = KEY_RESET_HW_DEFAULT;
+	} else if (val) {
+		if (val < 6 || val > 12) {
+			dev_err(&pdev->dev, "reset-time-sec out of range\n");
+			return -EINVAL;
+		}
+
+		reset_status = KEY_RESET_USER_SEL;
+		reset_time = (val - 6) / 2;
+	} else {
+		reset_status = KEY_RESET_DISABLED;
+		dev_dbg(&pdev->dev, "Disabled reset on long-press\n");
+	}
+
+	switch (atc260x->ic_type) {
+	case ATC2603C:
+		onkey->params = &atc2603c_onkey_params;
+		press_time = FIELD_PREP(ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_TIME,
+					press_time);
+		reset_time = FIELD_PREP(ATC2603C_PMU_SYS_CTL2_ONOFF_RESET_TIME_SEL,
+					reset_time);
+		break;
+	case ATC2609A:
+		onkey->params = &atc2609a_onkey_params;
+		press_time = FIELD_PREP(ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS_TIME,
+					press_time);
+		reset_time = FIELD_PREP(ATC2609A_PMU_SYS_CTL2_ONOFF_RESET_TIME_SEL,
+					reset_time);
+		break;
+	default:
+		dev_err(&pdev->dev,
+			"OnKey not supported for ATC260x PMIC type: %u\n",
+			atc260x->ic_type);
+		return -EINVAL;
+	}
+
+	input_dev = devm_input_allocate_device(&pdev->dev);
+	if (!input_dev) {
+		dev_err(&pdev->dev, "Failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	onkey->input_dev = input_dev;
+	onkey->atc260x = atc260x;
+
+	input_dev->name = "atc260x-onkey";
+	input_dev->phys = "atc260x-onkey/input0";
+	input_dev->open = atc260x_onkey_open;
+	input_dev->close = atc260x_onkey_close;
+
+	input_set_capability(input_dev, EV_KEY, KEY_POWER);
+	input_set_drvdata(input_dev, onkey);
+
+	INIT_DELAYED_WORK(&onkey->work, atc260x_onkey_work);
+
+	onkey->irq = platform_get_irq(pdev, 0);
+	if (onkey->irq < 0)
+		return onkey->irq;
+
+	error = devm_request_threaded_irq(&pdev->dev, onkey->irq, NULL,
+					  atc260x_onkey_irq, IRQF_ONESHOT,
+					  dev_name(&pdev->dev), onkey);
+	if (error) {
+		dev_err(&pdev->dev,
+			"Failed to register IRQ %d: %d\n", onkey->irq, error);
+		return error;
+	}
+
+	/* Keep IRQ disabled until atc260x_onkey_open() is called. */
+	disable_irq(onkey->irq);
+
+	error = input_register_device(input_dev);
+	if (error) {
+		dev_err(&pdev->dev,
+			"Failed to register input device: %d\n", error);
+		return error;
+	}
+
+	error = atc2603x_onkey_hw_init(onkey, reset_status,
+				       reset_time, press_time);
+	if (error)
+		return error;
+
+	device_init_wakeup(&pdev->dev, true);
+
+	return 0;
+}
+
+static struct platform_driver atc260x_onkey_driver = {
+	.probe	= atc260x_onkey_probe,
+	.driver	= {
+		.name = "atc260x-onkey",
+	},
+};
+
+module_platform_driver(atc260x_onkey_driver);
+
+MODULE_DESCRIPTION("Onkey driver for ATC260x PMICs");
+MODULE_AUTHOR("Cristian Ciocaltea <cristian.ciocaltea@gmail.com>");
+MODULE_LICENSE("GPL");