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, 258 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-max7360.c b/drivers/gpio/gpio-max7360.c
new file mode 100644
index 000000000..6755d58c4
--- /dev/null
+++ b/drivers/gpio/gpio-max7360.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2025 Bootlin
+ *
+ * Author: Kamel BOUHARA <kamel.bouhara@bootlin.com>
+ * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitmap.h>
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/regmap.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/max7360.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define MAX7360_GPIO_PORT	1
+#define MAX7360_GPIO_COL	2
+
+struct max7360_gpio_plat_data {
+	unsigned int function;
+};
+
+static struct max7360_gpio_plat_data max7360_gpio_port_plat = { .function = MAX7360_GPIO_PORT };
+static struct max7360_gpio_plat_data max7360_gpio_col_plat = { .function = MAX7360_GPIO_COL };
+
+static int max7360_get_available_gpos(struct device *dev, unsigned int *available_gpios)
+{
+	u32 columns;
+	int ret;
+
+	ret = device_property_read_u32(dev->parent, "keypad,num-columns", &columns);
+	if (ret) {
+		dev_err(dev, "Failed to read columns count\n");
+		return ret;
+	}
+
+	*available_gpios = min(MAX7360_MAX_GPO, MAX7360_MAX_KEY_COLS - columns);
+
+	return 0;
+}
+
+static int max7360_gpo_init_valid_mask(struct gpio_chip *gc,
+				       unsigned long *valid_mask,
+				       unsigned int ngpios)
+{
+	unsigned int available_gpios;
+	int ret;
+
+	ret = max7360_get_available_gpos(gc->parent, &available_gpios);
+	if (ret)
+		return ret;
+
+	bitmap_clear(valid_mask, 0, MAX7360_MAX_KEY_COLS - available_gpios);
+
+	return 0;
+}
+
+static int max7360_set_gpos_count(struct device *dev, struct regmap *regmap)
+{
+	/*
+	 * MAX7360 COL0 to COL7 pins can be used either as keypad columns,
+	 * general purpose output or a mix of both.
+	 * By default, all pins are used as keypad, here we update this
+	 * configuration to allow to use some of them as GPIOs.
+	 */
+	unsigned int available_gpios;
+	unsigned int val;
+	int ret;
+
+	ret = max7360_get_available_gpos(dev, &available_gpios);
+	if (ret)
+		return ret;
+
+	/*
+	 * Configure which GPIOs will be used for keypad.
+	 * MAX7360_REG_DEBOUNCE contains configuration both for keypad debounce
+	 * timings and gpos/keypad columns repartition. Only the later is
+	 * modified here.
+	 */
+	val = FIELD_PREP(MAX7360_PORTS, available_gpios);
+	ret = regmap_write_bits(regmap, MAX7360_REG_DEBOUNCE, MAX7360_PORTS, val);
+	if (ret)
+		dev_err(dev, "Failed to write max7360 columns/gpos configuration");
+
+	return ret;
+}
+
+static int max7360_gpio_reg_mask_xlate(struct gpio_regmap *gpio,
+				       enum gpio_regmap_operation op,
+				       unsigned int base, unsigned int offset,
+				       unsigned int *reg, unsigned int *mask)
+{
+	if (base == MAX7360_REG_PWMBASE) {
+		/*
+		 * GPIO output is using PWM duty cycle registers: one register
+		 * per line, with value being either 0 or 255.
+		 */
+		*reg = base + offset;
+		*mask = GENMASK(7, 0);
+	} else {
+		*reg = base;
+		*mask = BIT(offset);
+	}
+
+	return 0;
+}
+
+static const struct regmap_irq max7360_regmap_irqs[MAX7360_MAX_GPIO] = {
+	REGMAP_IRQ_REG(0, 0, BIT(0)),
+	REGMAP_IRQ_REG(1, 0, BIT(1)),
+	REGMAP_IRQ_REG(2, 0, BIT(2)),
+	REGMAP_IRQ_REG(3, 0, BIT(3)),
+	REGMAP_IRQ_REG(4, 0, BIT(4)),
+	REGMAP_IRQ_REG(5, 0, BIT(5)),
+	REGMAP_IRQ_REG(6, 0, BIT(6)),
+	REGMAP_IRQ_REG(7, 0, BIT(7)),
+};
+
+static int max7360_handle_mask_sync(const int index,
+				    const unsigned int mask_buf_def,
+				    const unsigned int mask_buf,
+				    void *const irq_drv_data)
+{
+	struct regmap *regmap = gpio_regmap_get_drvdata(irq_drv_data);
+	int ret;
+
+	for (unsigned int i = 0; i < MAX7360_MAX_GPIO; i++) {
+		ret = regmap_assign_bits(regmap, MAX7360_REG_PWMCFG(i),
+					 MAX7360_PORT_CFG_INTERRUPT_MASK, mask_buf & BIT(i));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int max7360_gpio_probe(struct platform_device *pdev)
+{
+	const struct max7360_gpio_plat_data *plat_data;
+	struct gpio_regmap_config gpio_config = { };
+	struct regmap_irq_chip *irq_chip;
+	struct device *dev = &pdev->dev;
+	struct regmap *regmap;
+	unsigned int outconf;
+	int ret;
+
+	regmap = dev_get_regmap(dev->parent, NULL);
+	if (!regmap)
+		return dev_err_probe(dev, -ENODEV, "could not get parent regmap\n");
+
+	plat_data = device_get_match_data(dev);
+	if (plat_data->function == MAX7360_GPIO_PORT) {
+		if (device_property_read_bool(dev, "interrupt-controller")) {
+			/*
+			 * Port GPIOs with interrupt-controller property: add IRQ
+			 * controller.
+			 */
+			gpio_config.regmap_irq_flags = IRQF_ONESHOT | IRQF_SHARED;
+			gpio_config.regmap_irq_line =
+				fwnode_irq_get_byname(dev_fwnode(dev->parent), "inti");
+			if (gpio_config.regmap_irq_line < 0)
+				return dev_err_probe(dev, gpio_config.regmap_irq_line,
+						     "Failed to get IRQ\n");
+
+			/* Create custom IRQ configuration. */
+			irq_chip = devm_kzalloc(dev, sizeof(*irq_chip), GFP_KERNEL);
+			if (!irq_chip)
+				return -ENOMEM;
+
+			irq_chip->name = dev_name(dev);
+			irq_chip->status_base = MAX7360_REG_GPIOIN;
+			irq_chip->status_is_level = true;
+			irq_chip->num_regs = 1;
+			irq_chip->num_irqs = MAX7360_MAX_GPIO;
+			irq_chip->irqs = max7360_regmap_irqs;
+			irq_chip->handle_mask_sync = max7360_handle_mask_sync;
+
+			gpio_config.regmap_irq_chip = irq_chip;
+			gpio_config.drvdata = regmap;
+
+			for (unsigned int i = 0; i < MAX7360_MAX_GPIO; i++) {
+				ret = regmap_write_bits(regmap, MAX7360_REG_PWMCFG(i),
+							MAX7360_PORT_CFG_INTERRUPT_EDGES,
+							MAX7360_PORT_CFG_INTERRUPT_EDGES);
+				if (ret)
+					return dev_err_probe(dev, ret,
+							     "Failed to enable interrupts\n");
+			}
+		}
+
+		/*
+		 * Port GPIOs: set output mode configuration (constant-current or not).
+		 * This property is optional.
+		 */
+		ret = device_property_read_u32(dev, "maxim,constant-current-disable", &outconf);
+		if (!ret) {
+			ret = regmap_write(regmap, MAX7360_REG_GPIOOUTM, outconf);
+			if (ret)
+				return dev_err_probe(dev, ret,
+						     "Failed to set constant-current configuration\n");
+		}
+	}
+
+	/* Add gpio device. */
+	gpio_config.parent = dev;
+	gpio_config.regmap = regmap;
+	if (plat_data->function == MAX7360_GPIO_PORT) {
+		gpio_config.ngpio = MAX7360_MAX_GPIO;
+		gpio_config.reg_dat_base = GPIO_REGMAP_ADDR(MAX7360_REG_GPIOIN);
+		gpio_config.reg_set_base = GPIO_REGMAP_ADDR(MAX7360_REG_PWMBASE);
+		gpio_config.reg_dir_out_base = GPIO_REGMAP_ADDR(MAX7360_REG_GPIOCTRL);
+		gpio_config.ngpio_per_reg = MAX7360_MAX_GPIO;
+		gpio_config.reg_mask_xlate = max7360_gpio_reg_mask_xlate;
+	} else {
+		ret = max7360_set_gpos_count(dev, regmap);
+		if (ret)
+			return dev_err_probe(dev, ret, "Failed to set GPOS pin count\n");
+
+		gpio_config.reg_set_base = GPIO_REGMAP_ADDR(MAX7360_REG_PORTS);
+		gpio_config.ngpio = MAX7360_MAX_KEY_COLS;
+		gpio_config.init_valid_mask = max7360_gpo_init_valid_mask;
+	}
+
+	return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
+}
+
+static const struct of_device_id max7360_gpio_of_match[] = {
+	{
+		.compatible = "maxim,max7360-gpo",
+		.data = &max7360_gpio_col_plat
+	}, {
+		.compatible = "maxim,max7360-gpio",
+		.data = &max7360_gpio_port_plat
+	}, {
+	}
+};
+MODULE_DEVICE_TABLE(of, max7360_gpio_of_match);
+
+static struct platform_driver max7360_gpio_driver = {
+	.driver = {
+		.name	= "max7360-gpio",
+		.of_match_table = max7360_gpio_of_match,
+	},
+	.probe		= max7360_gpio_probe,
+};
+module_platform_driver(max7360_gpio_driver);
+
+MODULE_DESCRIPTION("MAX7360 GPIO driver");
+MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@bootlin.com>");
+MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
+MODULE_LICENSE("GPL");