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, 300 insertions, 0 deletions

diff --git a/drivers/pinctrl/pinctrl-da9062.c b/drivers/pinctrl/pinctrl-da9062.c
new file mode 100644
index 000000000..53298cbcc
--- /dev/null
+++ b/drivers/pinctrl/pinctrl-da9062.c
@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Dialog DA9062 pinctrl and GPIO driver.
+ * Based on DA9055 GPIO driver.
+ *
+ * TODO:
+ *   - add pinmux and pinctrl support (gpio alternate mode)
+ *
+ * Documents:
+ * [1] https://www.dialog-semiconductor.com/sites/default/files/da9062_datasheet_3v6.pdf
+ *
+ * Copyright (C) 2019 Pengutronix, Marco Felsch <kernel@pengutronix.de>
+ */
+#include <linux/bits.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+
+#include <linux/mfd/da9062/core.h>
+#include <linux/mfd/da9062/registers.h>
+
+#define DA9062_TYPE(offset)		(4 * (offset % 2))
+#define DA9062_PIN_SHIFT(offset)	(4 * (offset % 2))
+#define DA9062_PIN_ALTERNATE		0x00 /* gpio alternate mode */
+#define DA9062_PIN_GPI			0x01 /* gpio in */
+#define DA9062_PIN_GPO_OD		0x02 /* gpio out open-drain */
+#define DA9062_PIN_GPO_PP		0x03 /* gpio out push-pull */
+#define DA9062_GPIO_NUM			5
+
+struct da9062_pctl {
+	struct da9062 *da9062;
+	struct gpio_chip gc;
+	unsigned int pin_config[DA9062_GPIO_NUM];
+};
+
+static int da9062_pctl_get_pin_mode(struct da9062_pctl *pctl,
+				    unsigned int offset)
+{
+	struct regmap *regmap = pctl->da9062->regmap;
+	int ret, val;
+
+	ret = regmap_read(regmap, DA9062AA_GPIO_0_1 + (offset >> 1), &val);
+	if (ret < 0)
+		return ret;
+
+	val >>= DA9062_PIN_SHIFT(offset);
+	val &= DA9062AA_GPIO0_PIN_MASK;
+
+	return val;
+}
+
+static int da9062_pctl_set_pin_mode(struct da9062_pctl *pctl,
+				    unsigned int offset, unsigned int mode_req)
+{
+	struct regmap *regmap = pctl->da9062->regmap;
+	unsigned int mode = mode_req;
+	unsigned int mask;
+	int ret;
+
+	mode &= DA9062AA_GPIO0_PIN_MASK;
+	mode <<= DA9062_PIN_SHIFT(offset);
+	mask = DA9062AA_GPIO0_PIN_MASK << DA9062_PIN_SHIFT(offset);
+
+	ret = regmap_update_bits(regmap, DA9062AA_GPIO_0_1 + (offset >> 1),
+				 mask, mode);
+	if (!ret)
+		pctl->pin_config[offset] = mode_req;
+
+	return ret;
+}
+
+static int da9062_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+	struct da9062_pctl *pctl = gpiochip_get_data(gc);
+	struct regmap *regmap = pctl->da9062->regmap;
+	int gpio_mode, val;
+	int ret;
+
+	gpio_mode = da9062_pctl_get_pin_mode(pctl, offset);
+	if (gpio_mode < 0)
+		return gpio_mode;
+
+	switch (gpio_mode) {
+	case DA9062_PIN_ALTERNATE:
+		return -ENOTSUPP;
+	case DA9062_PIN_GPI:
+		ret = regmap_read(regmap, DA9062AA_STATUS_B, &val);
+		if (ret < 0)
+			return ret;
+		break;
+	case DA9062_PIN_GPO_OD:
+	case DA9062_PIN_GPO_PP:
+		ret = regmap_read(regmap, DA9062AA_GPIO_MODE0_4, &val);
+		if (ret < 0)
+			return ret;
+	}
+
+	return !!(val & BIT(offset));
+}
+
+static int da9062_gpio_set(struct gpio_chip *gc, unsigned int offset,
+			   int value)
+{
+	struct da9062_pctl *pctl = gpiochip_get_data(gc);
+	struct regmap *regmap = pctl->da9062->regmap;
+
+	return regmap_update_bits(regmap, DA9062AA_GPIO_MODE0_4, BIT(offset),
+				  value << offset);
+}
+
+static int da9062_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+	struct da9062_pctl *pctl = gpiochip_get_data(gc);
+	int gpio_mode;
+
+	gpio_mode = da9062_pctl_get_pin_mode(pctl, offset);
+	if (gpio_mode < 0)
+		return gpio_mode;
+
+	switch (gpio_mode) {
+	case DA9062_PIN_ALTERNATE:
+		return -ENOTSUPP;
+	case DA9062_PIN_GPI:
+		return GPIO_LINE_DIRECTION_IN;
+	case DA9062_PIN_GPO_OD:
+	case DA9062_PIN_GPO_PP:
+		return GPIO_LINE_DIRECTION_OUT;
+	}
+
+	return -EINVAL;
+}
+
+static int da9062_gpio_direction_input(struct gpio_chip *gc,
+				       unsigned int offset)
+{
+	struct da9062_pctl *pctl = gpiochip_get_data(gc);
+	struct regmap *regmap = pctl->da9062->regmap;
+	struct gpio_desc *desc = gpio_device_get_desc(gc->gpiodev, offset);
+	unsigned int gpi_type;
+	int ret;
+
+	ret = da9062_pctl_set_pin_mode(pctl, offset, DA9062_PIN_GPI);
+	if (ret)
+		return ret;
+
+	/*
+	 * If the gpio is active low we should set it in hw too. No worries
+	 * about gpio_get() because we read and return the gpio-level. So the
+	 * gpiolib active_low handling is still correct.
+	 *
+	 * 0 - active low, 1 - active high
+	 */
+	gpi_type = !gpiod_is_active_low(desc);
+
+	return regmap_update_bits(regmap, DA9062AA_GPIO_0_1 + (offset >> 1),
+				DA9062AA_GPIO0_TYPE_MASK << DA9062_TYPE(offset),
+				gpi_type << DA9062_TYPE(offset));
+}
+
+static int da9062_gpio_direction_output(struct gpio_chip *gc,
+					unsigned int offset, int value)
+{
+	struct da9062_pctl *pctl = gpiochip_get_data(gc);
+	unsigned int pin_config = pctl->pin_config[offset];
+	int ret;
+
+	ret = da9062_pctl_set_pin_mode(pctl, offset, pin_config);
+	if (ret)
+		return ret;
+
+	return da9062_gpio_set(gc, offset, value);
+}
+
+static int da9062_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
+				  unsigned long config)
+{
+	struct da9062_pctl *pctl = gpiochip_get_data(gc);
+	struct regmap *regmap = pctl->da9062->regmap;
+	int gpio_mode;
+
+	/*
+	 * We need to meet the following restrictions [1, Figure 18]:
+	 * - PIN_CONFIG_BIAS_PULL_DOWN -> only allowed if the pin is used as
+	 *				  gpio input
+	 * - PIN_CONFIG_BIAS_PULL_UP   -> only allowed if the pin is used as
+	 *				  gpio output open-drain.
+	 */
+
+	switch (pinconf_to_config_param(config)) {
+	case PIN_CONFIG_BIAS_DISABLE:
+		return regmap_update_bits(regmap, DA9062AA_CONFIG_K,
+					  BIT(offset), 0);
+	case PIN_CONFIG_BIAS_PULL_DOWN:
+		gpio_mode = da9062_pctl_get_pin_mode(pctl, offset);
+		if (gpio_mode < 0)
+			return -EINVAL;
+		else if (gpio_mode != DA9062_PIN_GPI)
+			return -ENOTSUPP;
+		return regmap_update_bits(regmap, DA9062AA_CONFIG_K,
+					  BIT(offset), BIT(offset));
+	case PIN_CONFIG_BIAS_PULL_UP:
+		gpio_mode = da9062_pctl_get_pin_mode(pctl, offset);
+		if (gpio_mode < 0)
+			return -EINVAL;
+		else if (gpio_mode != DA9062_PIN_GPO_OD)
+			return -ENOTSUPP;
+		return regmap_update_bits(regmap, DA9062AA_CONFIG_K,
+					  BIT(offset), BIT(offset));
+	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+		return da9062_pctl_set_pin_mode(pctl, offset,
+						DA9062_PIN_GPO_OD);
+	case PIN_CONFIG_DRIVE_PUSH_PULL:
+		return da9062_pctl_set_pin_mode(pctl, offset,
+						DA9062_PIN_GPO_PP);
+	default:
+		return -ENOTSUPP;
+	}
+}
+
+static int da9062_gpio_to_irq(struct gpio_chip *gc, unsigned int offset)
+{
+	struct da9062_pctl *pctl = gpiochip_get_data(gc);
+	struct da9062 *da9062 = pctl->da9062;
+
+	return regmap_irq_get_virq(da9062->regmap_irq,
+				   DA9062_IRQ_GPI0 + offset);
+}
+
+static const struct gpio_chip reference_gc = {
+	.owner = THIS_MODULE,
+	.get = da9062_gpio_get,
+	.set = da9062_gpio_set,
+	.get_direction = da9062_gpio_get_direction,
+	.direction_input = da9062_gpio_direction_input,
+	.direction_output = da9062_gpio_direction_output,
+	.set_config = da9062_gpio_set_config,
+	.to_irq = da9062_gpio_to_irq,
+	.can_sleep = true,
+	.ngpio = DA9062_GPIO_NUM,
+	.base = -1,
+};
+
+static int da9062_pctl_probe(struct platform_device *pdev)
+{
+	struct device *parent = pdev->dev.parent;
+	struct da9062_pctl *pctl;
+	int i;
+
+	device_set_node(&pdev->dev, dev_fwnode(pdev->dev.parent));
+
+	pctl = devm_kzalloc(&pdev->dev, sizeof(*pctl), GFP_KERNEL);
+	if (!pctl)
+		return -ENOMEM;
+
+	pctl->da9062 = dev_get_drvdata(parent);
+	if (!pctl->da9062)
+		return -EINVAL;
+
+	if (!device_property_present(parent, "gpio-controller"))
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(pctl->pin_config); i++)
+		pctl->pin_config[i] = DA9062_PIN_GPO_PP;
+
+	/*
+	 * Currently the driver handles only the GPIO support. The
+	 * pinctrl/pinmux support can be added later if needed.
+	 */
+	pctl->gc = reference_gc;
+	pctl->gc.label = dev_name(&pdev->dev);
+	pctl->gc.parent = &pdev->dev;
+
+	platform_set_drvdata(pdev, pctl);
+
+	return devm_gpiochip_add_data(&pdev->dev, &pctl->gc, pctl);
+}
+
+static const struct of_device_id da9062_compatible_reg_id_table[] = {
+	{ .compatible = "dlg,da9062-gpio" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, da9062_compatible_reg_id_table);
+
+static struct platform_driver da9062_pctl_driver = {
+	.probe = da9062_pctl_probe,
+	.driver = {
+		.name	= "da9062-gpio",
+		.of_match_table = da9062_compatible_reg_id_table,
+	},
+};
+module_platform_driver(da9062_pctl_driver);
+
+MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("DA9062 PMIC pinctrl and GPIO Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:da9062-gpio");