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, 249 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-usbio.c b/drivers/gpio/gpio-usbio.c
new file mode 100644
index 000000000..489c8ac62
--- /dev/null
+++ b/drivers/gpio/gpio-usbio.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2025 Intel Corporation.
+ * Copyright (c) 2025 Red Hat, Inc.
+ */
+
+#include <linux/acpi.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/cleanup.h>
+#include <linux/device.h>
+#include <linux/gpio/driver.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/usb/usbio.h>
+
+struct usbio_gpio_bank {
+	u8 config[USBIO_GPIOSPERBANK];
+	u32 bitmap;
+};
+
+struct usbio_gpio {
+	struct mutex config_mutex; /* Protects banks[x].config */
+	struct usbio_gpio_bank banks[USBIO_MAX_GPIOBANKS];
+	struct gpio_chip gc;
+	struct auxiliary_device *adev;
+};
+
+static const struct acpi_device_id usbio_gpio_acpi_hids[] = {
+	{ "INTC1007" }, /* MTL */
+	{ "INTC10B2" }, /* ARL */
+	{ "INTC10B5" }, /* LNL */
+	{ "INTC10D1" }, /* MTL-CVF */
+	{ "INTC10E2" }, /* PTL */
+	{ "INTC1116" }, /* NVL */
+	{ }
+};
+
+static void usbio_gpio_get_bank_and_pin(struct gpio_chip *gc, unsigned int offset,
+					struct usbio_gpio_bank **bank_ret,
+					unsigned int *pin_ret)
+{
+	struct usbio_gpio *gpio = gpiochip_get_data(gc);
+	struct device *dev = &gpio->adev->dev;
+	struct usbio_gpio_bank *bank;
+	unsigned int pin;
+
+	bank = &gpio->banks[offset / USBIO_GPIOSPERBANK];
+	pin = offset % USBIO_GPIOSPERBANK;
+	if (~bank->bitmap & BIT(pin)) {
+		/* The FW bitmap sometimes is invalid, warn and continue */
+		dev_warn_once(dev, FW_BUG "GPIO %u is not in FW pins bitmap\n", offset);
+	}
+
+	*bank_ret = bank;
+	*pin_ret = pin;
+}
+
+static int usbio_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+	struct usbio_gpio_bank *bank;
+	unsigned int pin;
+	u8 cfg;
+
+	usbio_gpio_get_bank_and_pin(gc, offset, &bank, &pin);
+
+	cfg = bank->config[pin] & USBIO_GPIO_PINMOD_MASK;
+
+	return (cfg == USBIO_GPIO_PINMOD_OUTPUT) ?
+		GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
+}
+
+static int usbio_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+	struct usbio_gpio *gpio = gpiochip_get_data(gc);
+	struct usbio_gpio_bank *bank;
+	struct usbio_gpio_rw gbuf;
+	unsigned int pin;
+	int ret;
+
+	usbio_gpio_get_bank_and_pin(gc, offset, &bank, &pin);
+
+	gbuf.bankid = offset / USBIO_GPIOSPERBANK;
+	gbuf.pincount  = 1;
+	gbuf.pin = pin;
+
+	ret = usbio_control_msg(gpio->adev, USBIO_PKTTYPE_GPIO, USBIO_GPIOCMD_READ,
+				&gbuf, sizeof(gbuf) - sizeof(gbuf.value),
+				&gbuf, sizeof(gbuf));
+	if (ret != sizeof(gbuf))
+		return (ret < 0) ? ret : -EPROTO;
+
+	return (le32_to_cpu(gbuf.value) >> pin) & 1;
+}
+
+static int usbio_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
+{
+	struct usbio_gpio *gpio = gpiochip_get_data(gc);
+	struct usbio_gpio_bank *bank;
+	struct usbio_gpio_rw gbuf;
+	unsigned int pin;
+
+	usbio_gpio_get_bank_and_pin(gc, offset, &bank, &pin);
+
+	gbuf.bankid = offset / USBIO_GPIOSPERBANK;
+	gbuf.pincount  = 1;
+	gbuf.pin = pin;
+	gbuf.value = cpu_to_le32(value << pin);
+
+	return usbio_control_msg(gpio->adev, USBIO_PKTTYPE_GPIO, USBIO_GPIOCMD_WRITE,
+				 &gbuf, sizeof(gbuf), NULL, 0);
+}
+
+static int usbio_gpio_update_config(struct gpio_chip *gc, unsigned int offset,
+				    u8 mask, u8 value)
+{
+	struct usbio_gpio *gpio = gpiochip_get_data(gc);
+	struct usbio_gpio_bank *bank;
+	struct usbio_gpio_init gbuf;
+	unsigned int pin;
+
+	usbio_gpio_get_bank_and_pin(gc, offset, &bank, &pin);
+
+	guard(mutex)(&gpio->config_mutex);
+
+	bank->config[pin] &= ~mask;
+	bank->config[pin] |= value;
+
+	gbuf.bankid = offset / USBIO_GPIOSPERBANK;
+	gbuf.config = bank->config[pin];
+	gbuf.pincount  = 1;
+	gbuf.pin = pin;
+
+	return usbio_control_msg(gpio->adev, USBIO_PKTTYPE_GPIO, USBIO_GPIOCMD_INIT,
+				 &gbuf, sizeof(gbuf), NULL, 0);
+}
+
+static int usbio_gpio_direction_input(struct gpio_chip *gc, unsigned int offset)
+{
+	return usbio_gpio_update_config(gc, offset, USBIO_GPIO_PINMOD_MASK,
+					USBIO_GPIO_SET_PINMOD(USBIO_GPIO_PINMOD_INPUT));
+}
+
+static int usbio_gpio_direction_output(struct gpio_chip *gc,
+		unsigned int offset, int value)
+{
+	int ret;
+
+	ret = usbio_gpio_update_config(gc, offset, USBIO_GPIO_PINMOD_MASK,
+				       USBIO_GPIO_SET_PINMOD(USBIO_GPIO_PINMOD_OUTPUT));
+	if (ret)
+		return ret;
+
+	return usbio_gpio_set(gc, offset, value);
+}
+
+static int usbio_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
+		unsigned long config)
+{
+	u8 value;
+
+	switch (pinconf_to_config_param(config)) {
+	case PIN_CONFIG_BIAS_PULL_PIN_DEFAULT:
+		value = USBIO_GPIO_SET_PINCFG(USBIO_GPIO_PINCFG_DEFAULT);
+		break;
+	case PIN_CONFIG_BIAS_PULL_UP:
+		value = USBIO_GPIO_SET_PINCFG(USBIO_GPIO_PINCFG_PULLUP);
+		break;
+	case PIN_CONFIG_BIAS_PULL_DOWN:
+		value = USBIO_GPIO_SET_PINCFG(USBIO_GPIO_PINCFG_PULLDOWN);
+		break;
+	case PIN_CONFIG_DRIVE_PUSH_PULL:
+		value = USBIO_GPIO_SET_PINCFG(USBIO_GPIO_PINCFG_PUSHPULL);
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	return usbio_gpio_update_config(gc, offset, USBIO_GPIO_PINCFG_MASK, value);
+}
+
+static int usbio_gpio_probe(struct auxiliary_device *adev,
+		const struct auxiliary_device_id *adev_id)
+{
+	struct usbio_gpio_bank_desc *bank_desc;
+	struct device *dev = &adev->dev;
+	struct usbio_gpio *gpio;
+	int bank, ret;
+
+	bank_desc = dev_get_platdata(dev);
+	if (!bank_desc)
+		return -EINVAL;
+
+	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+
+	ret = devm_mutex_init(dev, &gpio->config_mutex);
+	if (ret)
+		return ret;
+
+	gpio->adev = adev;
+
+	usbio_acpi_bind(gpio->adev, usbio_gpio_acpi_hids);
+
+	for (bank = 0; bank < USBIO_MAX_GPIOBANKS && bank_desc[bank].bmap; bank++)
+		gpio->banks[bank].bitmap = le32_to_cpu(bank_desc[bank].bmap);
+
+	gpio->gc.label = ACPI_COMPANION(dev) ?
+					acpi_dev_name(ACPI_COMPANION(dev)) : dev_name(dev);
+	gpio->gc.parent = dev;
+	gpio->gc.owner = THIS_MODULE;
+	gpio->gc.get_direction = usbio_gpio_get_direction;
+	gpio->gc.direction_input = usbio_gpio_direction_input;
+	gpio->gc.direction_output = usbio_gpio_direction_output;
+	gpio->gc.get = usbio_gpio_get;
+	gpio->gc.set = usbio_gpio_set;
+	gpio->gc.set_config = usbio_gpio_set_config;
+	gpio->gc.base = -1;
+	gpio->gc.ngpio = bank * USBIO_GPIOSPERBANK;
+	gpio->gc.can_sleep = true;
+
+	ret = devm_gpiochip_add_data(dev, &gpio->gc, gpio);
+	if (ret)
+		return ret;
+
+	if (has_acpi_companion(dev))
+		acpi_dev_clear_dependencies(ACPI_COMPANION(dev));
+
+	return 0;
+}
+
+static const struct auxiliary_device_id usbio_gpio_id_table[] = {
+	{ "usbio.usbio-gpio" },
+	{ }
+};
+MODULE_DEVICE_TABLE(auxiliary, usbio_gpio_id_table);
+
+static struct auxiliary_driver usbio_gpio_driver = {
+	.name = USBIO_GPIO_CLIENT,
+	.probe = usbio_gpio_probe,
+	.id_table = usbio_gpio_id_table
+};
+module_auxiliary_driver(usbio_gpio_driver);
+
+MODULE_DESCRIPTION("Intel USBIO GPIO driver");
+MODULE_AUTHOR("Israel Cepeda <israel.a.cepeda.lopez@intel.com>");
+MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("USBIO");