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, 298 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/88pm860x-ts.c b/drivers/input/touchscreen/88pm860x-ts.c
new file mode 100644
index 000000000..0468ce2b2
--- /dev/null
+++ b/drivers/input/touchscreen/88pm860x-ts.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Touchscreen driver for Marvell 88PM860x
+ *
+ * Copyright (C) 2009 Marvell International Ltd.
+ * 	Haojian Zhuang <haojian.zhuang@marvell.com>
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/mfd/88pm860x.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+
+#define MEAS_LEN		(8)
+#define ACCURATE_BIT		(12)
+
+/* touch register */
+#define MEAS_EN3		(0x52)
+
+#define MEAS_TSIX_1		(0x8D)
+#define MEAS_TSIX_2		(0x8E)
+#define MEAS_TSIY_1		(0x8F)
+#define MEAS_TSIY_2		(0x90)
+#define MEAS_TSIZ1_1		(0x91)
+#define MEAS_TSIZ1_2		(0x92)
+#define MEAS_TSIZ2_1		(0x93)
+#define MEAS_TSIZ2_2		(0x94)
+
+/* bit definitions of touch */
+#define MEAS_PD_EN		(1 << 3)
+#define MEAS_TSIX_EN		(1 << 4)
+#define MEAS_TSIY_EN		(1 << 5)
+#define MEAS_TSIZ1_EN		(1 << 6)
+#define MEAS_TSIZ2_EN		(1 << 7)
+
+struct pm860x_touch {
+	struct input_dev *idev;
+	struct i2c_client *i2c;
+	struct pm860x_chip *chip;
+	int irq;
+	int res_x;		/* resistor of Xplate */
+};
+
+static irqreturn_t pm860x_touch_handler(int irq, void *data)
+{
+	struct pm860x_touch *touch = data;
+	struct pm860x_chip *chip = touch->chip;
+	unsigned char buf[MEAS_LEN];
+	int x, y, pen_down;
+	int z1, z2, rt = 0;
+	int ret;
+
+	ret = pm860x_bulk_read(touch->i2c, MEAS_TSIX_1, MEAS_LEN, buf);
+	if (ret < 0)
+		goto out;
+
+	pen_down = buf[1] & (1 << 6);
+	x = ((buf[0] & 0xFF) << 4) | (buf[1] & 0x0F);
+	y = ((buf[2] & 0xFF) << 4) | (buf[3] & 0x0F);
+	z1 = ((buf[4] & 0xFF) << 4) | (buf[5] & 0x0F);
+	z2 = ((buf[6] & 0xFF) << 4) | (buf[7] & 0x0F);
+
+	if (pen_down) {
+		if ((x != 0) && (z1 != 0) && (touch->res_x != 0)) {
+			rt = z2 / z1 - 1;
+			rt = (rt * touch->res_x * x) >> ACCURATE_BIT;
+			dev_dbg(chip->dev, "z1:%d, z2:%d, rt:%d\n",
+				z1, z2, rt);
+		}
+		input_report_abs(touch->idev, ABS_X, x);
+		input_report_abs(touch->idev, ABS_Y, y);
+		input_report_abs(touch->idev, ABS_PRESSURE, rt);
+		input_report_key(touch->idev, BTN_TOUCH, 1);
+		dev_dbg(chip->dev, "pen down at [%d, %d].\n", x, y);
+	} else {
+		input_report_abs(touch->idev, ABS_PRESSURE, 0);
+		input_report_key(touch->idev, BTN_TOUCH, 0);
+		dev_dbg(chip->dev, "pen release\n");
+	}
+	input_sync(touch->idev);
+
+out:
+	return IRQ_HANDLED;
+}
+
+static int pm860x_touch_open(struct input_dev *dev)
+{
+	struct pm860x_touch *touch = input_get_drvdata(dev);
+	int data, ret;
+
+	data = MEAS_PD_EN | MEAS_TSIX_EN | MEAS_TSIY_EN
+		| MEAS_TSIZ1_EN | MEAS_TSIZ2_EN;
+	ret = pm860x_set_bits(touch->i2c, MEAS_EN3, data, data);
+	if (ret < 0)
+		goto out;
+	return 0;
+out:
+	return ret;
+}
+
+static void pm860x_touch_close(struct input_dev *dev)
+{
+	struct pm860x_touch *touch = input_get_drvdata(dev);
+	int data;
+
+	data = MEAS_PD_EN | MEAS_TSIX_EN | MEAS_TSIY_EN
+		| MEAS_TSIZ1_EN | MEAS_TSIZ2_EN;
+	pm860x_set_bits(touch->i2c, MEAS_EN3, data, 0);
+}
+
+#ifdef CONFIG_OF
+static int pm860x_touch_dt_init(struct platform_device *pdev,
+					  struct pm860x_chip *chip,
+					  int *res_x)
+{
+	struct i2c_client *i2c = (chip->id == CHIP_PM8607) ? chip->client \
+				 : chip->companion;
+	int data, n, ret;
+	if (!pdev->dev.parent->of_node)
+		return -ENODEV;
+
+	struct device_node *np __free(device_node) =
+		of_get_child_by_name(pdev->dev.parent->of_node, "touch");
+	if (!np) {
+		dev_err(&pdev->dev, "Can't find touch node\n");
+		return -EINVAL;
+	}
+	/* set GPADC MISC1 register */
+	data = 0;
+	if (!of_property_read_u32(np, "marvell,88pm860x-gpadc-prebias", &n))
+		data |= (n << 1) & PM8607_GPADC_PREBIAS_MASK;
+	if (!of_property_read_u32(np, "marvell,88pm860x-gpadc-slot-cycle", &n))
+		data |= (n << 3) & PM8607_GPADC_SLOT_CYCLE_MASK;
+	if (!of_property_read_u32(np, "marvell,88pm860x-gpadc-off-scale", &n))
+		data |= (n << 5) & PM8607_GPADC_OFF_SCALE_MASK;
+	if (!of_property_read_u32(np, "marvell,88pm860x-gpadc-sw-cal", &n))
+		data |= (n << 7) & PM8607_GPADC_SW_CAL_MASK;
+	if (data) {
+		ret = pm860x_reg_write(i2c, PM8607_GPADC_MISC1, data);
+		if (ret < 0)
+			return -EINVAL;
+	}
+	/* set tsi prebias time */
+	if (!of_property_read_u32(np, "marvell,88pm860x-tsi-prebias", &data)) {
+		ret = pm860x_reg_write(i2c, PM8607_TSI_PREBIAS, data);
+		if (ret < 0)
+			return -EINVAL;
+	}
+	/* set prebias & prechg time of pen detect */
+	data = 0;
+	if (!of_property_read_u32(np, "marvell,88pm860x-pen-prebias", &n))
+		data |= n & PM8607_PD_PREBIAS_MASK;
+	if (!of_property_read_u32(np, "marvell,88pm860x-pen-prechg", &n))
+		data |= n & PM8607_PD_PRECHG_MASK;
+	if (data) {
+		ret = pm860x_reg_write(i2c, PM8607_PD_PREBIAS, data);
+		if (ret < 0)
+			return -EINVAL;
+	}
+	of_property_read_u32(np, "marvell,88pm860x-resistor-X", res_x);
+
+	return 0;
+}
+#else
+#define pm860x_touch_dt_init(x, y, z)	(-1)
+#endif
+
+static int pm860x_touch_probe(struct platform_device *pdev)
+{
+	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
+	struct pm860x_touch_pdata *pdata = dev_get_platdata(&pdev->dev);
+	struct pm860x_touch *touch;
+	struct i2c_client *i2c = (chip->id == CHIP_PM8607) ? chip->client \
+				 : chip->companion;
+	int irq, ret, res_x = 0, data = 0;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return -EINVAL;
+
+	if (pm860x_touch_dt_init(pdev, chip, &res_x)) {
+		if (pdata) {
+			/* set GPADC MISC1 register */
+			data = 0;
+			data |= (pdata->gpadc_prebias << 1)
+				& PM8607_GPADC_PREBIAS_MASK;
+			data |= (pdata->slot_cycle << 3)
+				& PM8607_GPADC_SLOT_CYCLE_MASK;
+			data |= (pdata->off_scale << 5)
+				& PM8607_GPADC_OFF_SCALE_MASK;
+			data |= (pdata->sw_cal << 7)
+				& PM8607_GPADC_SW_CAL_MASK;
+			if (data) {
+				ret = pm860x_reg_write(i2c,
+					PM8607_GPADC_MISC1, data);
+				if (ret < 0)
+					return -EINVAL;
+			}
+			/* set tsi prebias time */
+			if (pdata->tsi_prebias) {
+				data = pdata->tsi_prebias;
+				ret = pm860x_reg_write(i2c,
+					PM8607_TSI_PREBIAS, data);
+				if (ret < 0)
+					return -EINVAL;
+			}
+			/* set prebias & prechg time of pen detect */
+			data = 0;
+			data |= pdata->pen_prebias
+				& PM8607_PD_PREBIAS_MASK;
+			data |= (pdata->pen_prechg << 5)
+				& PM8607_PD_PRECHG_MASK;
+			if (data) {
+				ret = pm860x_reg_write(i2c,
+					PM8607_PD_PREBIAS, data);
+				if (ret < 0)
+					return -EINVAL;
+			}
+			res_x = pdata->res_x;
+		} else {
+			dev_err(&pdev->dev, "failed to get platform data\n");
+			return -EINVAL;
+		}
+	}
+	/* enable GPADC */
+	ret = pm860x_set_bits(i2c, PM8607_GPADC_MISC1, PM8607_GPADC_EN,
+			      PM8607_GPADC_EN);
+	if (ret)
+		return ret;
+
+	touch = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_touch),
+			     GFP_KERNEL);
+	if (!touch)
+		return -ENOMEM;
+
+	touch->idev = devm_input_allocate_device(&pdev->dev);
+	if (!touch->idev) {
+		dev_err(&pdev->dev, "Failed to allocate input device!\n");
+		return -ENOMEM;
+	}
+
+	touch->idev->name = "88pm860x-touch";
+	touch->idev->phys = "88pm860x/input0";
+	touch->idev->id.bustype = BUS_I2C;
+	touch->idev->dev.parent = &pdev->dev;
+	touch->idev->open = pm860x_touch_open;
+	touch->idev->close = pm860x_touch_close;
+	touch->chip = chip;
+	touch->i2c = i2c;
+	touch->irq = irq;
+	touch->res_x = res_x;
+	input_set_drvdata(touch->idev, touch);
+
+	ret = devm_request_threaded_irq(&pdev->dev, touch->irq, NULL,
+					pm860x_touch_handler, IRQF_ONESHOT,
+					"touch", touch);
+	if (ret < 0)
+		return ret;
+
+	__set_bit(EV_ABS, touch->idev->evbit);
+	__set_bit(ABS_X, touch->idev->absbit);
+	__set_bit(ABS_Y, touch->idev->absbit);
+	__set_bit(ABS_PRESSURE, touch->idev->absbit);
+	__set_bit(EV_SYN, touch->idev->evbit);
+	__set_bit(EV_KEY, touch->idev->evbit);
+	__set_bit(BTN_TOUCH, touch->idev->keybit);
+
+	input_set_abs_params(touch->idev, ABS_X, 0, 1 << ACCURATE_BIT, 0, 0);
+	input_set_abs_params(touch->idev, ABS_Y, 0, 1 << ACCURATE_BIT, 0, 0);
+	input_set_abs_params(touch->idev, ABS_PRESSURE, 0, 1 << ACCURATE_BIT,
+				0, 0);
+
+	ret = input_register_device(touch->idev);
+	if (ret < 0) {
+		dev_err(chip->dev, "Failed to register touch!\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver pm860x_touch_driver = {
+	.driver	= {
+		.name	= "88pm860x-touch",
+	},
+	.probe	= pm860x_touch_probe,
+};
+module_platform_driver(pm860x_touch_driver);
+
+MODULE_DESCRIPTION("Touchscreen driver for Marvell Semiconductor 88PM860x");
+MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:88pm860x-touch");
+