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, 207 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-madera.c b/drivers/gpio/gpio-madera.c
new file mode 100644
index 000000000..551faf965
--- /dev/null
+++ b/drivers/gpio/gpio-madera.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GPIO support for Cirrus Logic Madera codecs
+ *
+ * Copyright (C) 2015-2018 Cirrus Logic
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/madera/core.h>
+#include <linux/mfd/madera/pdata.h>
+#include <linux/mfd/madera/registers.h>
+
+struct madera_gpio {
+	struct madera *madera;
+	/* storage space for the gpio_chip we're using */
+	struct gpio_chip gpio_chip;
+};
+
+static int madera_gpio_get_direction(struct gpio_chip *chip,
+				     unsigned int offset)
+{
+	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
+	struct madera *madera = madera_gpio->madera;
+	unsigned int reg_offset = 2 * offset;
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(madera->regmap, MADERA_GPIO1_CTRL_2 + reg_offset,
+			  &val);
+	if (ret < 0)
+		return ret;
+
+	if (val & MADERA_GP1_DIR_MASK)
+		return GPIO_LINE_DIRECTION_IN;
+
+	return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int madera_gpio_direction_in(struct gpio_chip *chip, unsigned int offset)
+{
+	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
+	struct madera *madera = madera_gpio->madera;
+	unsigned int reg_offset = 2 * offset;
+
+	return regmap_update_bits(madera->regmap,
+				  MADERA_GPIO1_CTRL_2 + reg_offset,
+				  MADERA_GP1_DIR_MASK, MADERA_GP1_DIR);
+}
+
+static int madera_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
+	struct madera *madera = madera_gpio->madera;
+	unsigned int reg_offset = 2 * offset;
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(madera->regmap, MADERA_GPIO1_CTRL_1 + reg_offset,
+			  &val);
+	if (ret < 0)
+		return ret;
+
+	return !!(val & MADERA_GP1_LVL_MASK);
+}
+
+static int madera_gpio_direction_out(struct gpio_chip *chip,
+				     unsigned int offset, int value)
+{
+	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
+	struct madera *madera = madera_gpio->madera;
+	unsigned int reg_offset = 2 * offset;
+	unsigned int reg_val = value ? MADERA_GP1_LVL : 0;
+	int ret;
+
+	ret = regmap_update_bits(madera->regmap,
+				 MADERA_GPIO1_CTRL_2 + reg_offset,
+				 MADERA_GP1_DIR_MASK, 0);
+	if (ret < 0)
+		return ret;
+
+	return regmap_update_bits(madera->regmap,
+				  MADERA_GPIO1_CTRL_1 + reg_offset,
+				  MADERA_GP1_LVL_MASK, reg_val);
+}
+
+static int madera_gpio_set(struct gpio_chip *chip, unsigned int offset,
+			   int value)
+{
+	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
+	struct madera *madera = madera_gpio->madera;
+	unsigned int reg_offset = 2 * offset;
+	unsigned int reg_val = value ? MADERA_GP1_LVL : 0;
+
+	return regmap_update_bits(madera->regmap,
+				  MADERA_GPIO1_CTRL_1 + reg_offset,
+				  MADERA_GP1_LVL_MASK, reg_val);
+}
+
+static const struct gpio_chip madera_gpio_chip = {
+	.label			= "madera",
+	.owner			= THIS_MODULE,
+	.request		= gpiochip_generic_request,
+	.free			= gpiochip_generic_free,
+	.get_direction		= madera_gpio_get_direction,
+	.direction_input	= madera_gpio_direction_in,
+	.get			= madera_gpio_get,
+	.direction_output	= madera_gpio_direction_out,
+	.set			= madera_gpio_set,
+	.set_config		= gpiochip_generic_config,
+	.can_sleep		= true,
+};
+
+static int madera_gpio_probe(struct platform_device *pdev)
+{
+	struct madera *madera = dev_get_drvdata(pdev->dev.parent);
+	struct madera_pdata *pdata = &madera->pdata;
+	struct madera_gpio *madera_gpio;
+	int ret;
+
+	madera_gpio = devm_kzalloc(&pdev->dev, sizeof(*madera_gpio),
+				   GFP_KERNEL);
+	if (!madera_gpio)
+		return -ENOMEM;
+
+	madera_gpio->madera = madera;
+
+	/* Construct suitable gpio_chip from the template in madera_gpio_chip */
+	madera_gpio->gpio_chip = madera_gpio_chip;
+	madera_gpio->gpio_chip.parent = pdev->dev.parent;
+
+	switch (madera->type) {
+	case CS47L15:
+		madera_gpio->gpio_chip.ngpio = CS47L15_NUM_GPIOS;
+		break;
+	case CS47L35:
+		madera_gpio->gpio_chip.ngpio = CS47L35_NUM_GPIOS;
+		break;
+	case CS47L85:
+	case WM1840:
+		madera_gpio->gpio_chip.ngpio = CS47L85_NUM_GPIOS;
+		break;
+	case CS47L90:
+	case CS47L91:
+		madera_gpio->gpio_chip.ngpio = CS47L90_NUM_GPIOS;
+		break;
+	case CS42L92:
+	case CS47L92:
+	case CS47L93:
+		madera_gpio->gpio_chip.ngpio = CS47L92_NUM_GPIOS;
+		break;
+	default:
+		dev_err(&pdev->dev, "Unknown chip variant %d\n", madera->type);
+		return -EINVAL;
+	}
+
+	/* We want to be usable on systems that don't use devicetree or acpi */
+	if (pdata->gpio_base)
+		madera_gpio->gpio_chip.base = pdata->gpio_base;
+	else
+		madera_gpio->gpio_chip.base = -1;
+
+	ret = devm_gpiochip_add_data(&pdev->dev,
+				     &madera_gpio->gpio_chip,
+				     madera_gpio);
+	if (ret < 0) {
+		dev_dbg(&pdev->dev, "Could not register gpiochip, %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * This is part of a composite MFD device which can only be used with
+	 * the corresponding pinctrl driver. On all supported silicon the GPIO
+	 * to pinctrl mapping is fixed in the silicon, so we register it
+	 * explicitly instead of requiring a redundant gpio-ranges in the
+	 * devicetree.
+	 * In any case we also want to work on systems that don't use devicetree
+	 * or acpi.
+	 */
+	ret = gpiochip_add_pin_range(&madera_gpio->gpio_chip, "madera-pinctrl",
+				     0, 0, madera_gpio->gpio_chip.ngpio);
+	if (ret) {
+		dev_dbg(&pdev->dev, "Failed to add pin range (%d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver madera_gpio_driver = {
+	.driver = {
+		.name	= "madera-gpio",
+	},
+	.probe		= madera_gpio_probe,
+};
+
+module_platform_driver(madera_gpio_driver);
+
+MODULE_SOFTDEP("pre: pinctrl-madera");
+MODULE_DESCRIPTION("GPIO interface for Madera codecs");
+MODULE_AUTHOR("Nariman Poushin <nariman@opensource.cirrus.com>");
+MODULE_AUTHOR("Richard Fitzgerald <rf@opensource.cirrus.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:madera-gpio");