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, 573 insertions, 0 deletions

diff --git a/drivers/hwmon/tc654.c b/drivers/hwmon/tc654.c
new file mode 100644
index 000000000..4af9f0e2c
--- /dev/null
+++ b/drivers/hwmon/tc654.c
@@ -0,0 +1,573 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * tc654.c - Linux kernel modules for fan speed controller
+ *
+ * Copyright (C) 2016 Allied Telesis Labs NZ
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include <linux/util_macros.h>
+
+enum tc654_regs {
+	TC654_REG_RPM1 = 0x00,	/* RPM Output 1 */
+	TC654_REG_RPM2 = 0x01,	/* RPM Output 2 */
+	TC654_REG_FAN_FAULT1 = 0x02,	/* Fan Fault 1 Threshold */
+	TC654_REG_FAN_FAULT2 = 0x03,	/* Fan Fault 2 Threshold */
+	TC654_REG_CONFIG = 0x04,	/* Configuration */
+	TC654_REG_STATUS = 0x05,	/* Status */
+	TC654_REG_DUTY_CYCLE = 0x06,	/* Fan Speed Duty Cycle */
+	TC654_REG_MFR_ID = 0x07,	/* Manufacturer Identification */
+	TC654_REG_VER_ID = 0x08,	/* Version Identification */
+};
+
+/* Macros to easily index the registers */
+#define TC654_REG_RPM(idx)		(TC654_REG_RPM1 + (idx))
+#define TC654_REG_FAN_FAULT(idx)	(TC654_REG_FAN_FAULT1 + (idx))
+
+/* Config register bits */
+#define TC654_REG_CONFIG_RES		BIT(6)	/* Resolution Selection */
+#define TC654_REG_CONFIG_DUTYC		BIT(5)	/* Duty Cycle Control */
+#define TC654_REG_CONFIG_SDM		BIT(0)	/* Shutdown Mode */
+
+/* Status register bits */
+#define TC654_REG_STATUS_F2F		BIT(1)	/* Fan 2 Fault */
+#define TC654_REG_STATUS_F1F		BIT(0)	/* Fan 1 Fault */
+
+/* RPM resolution for RPM Output registers */
+#define TC654_HIGH_RPM_RESOLUTION	25	/* 25 RPM resolution */
+#define TC654_LOW_RPM_RESOLUTION	50	/* 50 RPM resolution */
+
+/* Convert to the fan fault RPM threshold from register value */
+#define TC654_FAN_FAULT_FROM_REG(val)	((val) * 50)	/* 50 RPM resolution */
+
+/* Convert to register value from the fan fault RPM threshold */
+#define TC654_FAN_FAULT_TO_REG(val)	(((val) / 50) & 0xff)
+
+/* Register data is read (and cached) at most once per second. */
+#define TC654_UPDATE_INTERVAL		HZ
+
+struct tc654_data {
+	struct i2c_client *client;
+
+	/* update mutex */
+	struct mutex update_lock;
+
+	/* tc654 register cache */
+	bool valid;
+	unsigned long last_updated;	/* in jiffies */
+
+	u8 rpm_output[2];	/* The fan RPM data for fans 1 and 2 is then
+				 * written to registers RPM1 and RPM2
+				 */
+	u8 fan_fault[2];	/* The Fan Fault Threshold Registers are used to
+				 * set the fan fault threshold levels for fan 1
+				 * and fan 2
+				 */
+	u8 config;	/* The Configuration Register is an 8-bit read/
+			 * writable multi-function control register
+			 *   7: Fan Fault Clear
+			 *      1 = Clear Fan Fault
+			 *      0 = Normal Operation (default)
+			 *   6: Resolution Selection for RPM Output Registers
+			 *      RPM Output Registers (RPM1 and RPM2) will be
+			 *      set for
+			 *      1 = 25 RPM (9-bit) resolution
+			 *      0 = 50 RPM (8-bit) resolution (default)
+			 *   5: Duty Cycle Control Method
+			 *      The V OUT duty cycle will be controlled via
+			 *      1 = the SMBus interface.
+			 *      0 = via the V IN analog input pin. (default)
+			 * 4,3: Fan 2 Pulses Per Rotation
+			 *      00 = 1
+			 *      01 = 2 (default)
+			 *      10 = 4
+			 *      11 = 8
+			 * 2,1: Fan 1 Pulses Per Rotation
+			 *      00 = 1
+			 *      01 = 2 (default)
+			 *      10 = 4
+			 *      11 = 8
+			 *   0: Shutdown Mode
+			 *      1 = Shutdown mode.
+			 *      0 = Normal operation. (default)
+			 */
+	u8 status;	/* The Status register provides all the information
+			 * about what is going on within the TC654/TC655
+			 * devices.
+			 * 7,6: Unimplemented, Read as '0'
+			 *   5: Over-Temperature Fault Condition
+			 *      1 = Over-Temperature condition has occurred
+			 *      0 = Normal operation. V IN is less than 2.6V
+			 *   4: RPM2 Counter Overflow
+			 *      1 = Fault condition
+			 *      0 = Normal operation
+			 *   3: RPM1 Counter Overflow
+			 *      1 = Fault condition
+			 *      0 = Normal operation
+			 *   2: V IN Input Status
+			 *      1 = V IN is open
+			 *      0 = Normal operation. voltage present at V IN
+			 *   1: Fan 2 Fault
+			 *      1 = Fault condition
+			 *      0 = Normal operation
+			 *   0: Fan 1 Fault
+			 *      1 = Fault condition
+			 *      0 = Normal operation
+			 */
+	u8 duty_cycle;	/* The DUTY_CYCLE register is a 4-bit read/
+			 * writable register used to control the duty
+			 * cycle of the V OUT output.
+			 */
+};
+
+/* helper to grab and cache data, at most one time per second */
+static struct tc654_data *tc654_update_client(struct device *dev)
+{
+	struct tc654_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	int ret = 0;
+
+	mutex_lock(&data->update_lock);
+	if (time_before(jiffies, data->last_updated + TC654_UPDATE_INTERVAL) &&
+	    likely(data->valid))
+		goto out;
+
+	ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(0));
+	if (ret < 0)
+		goto out;
+	data->rpm_output[0] = ret;
+
+	ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(1));
+	if (ret < 0)
+		goto out;
+	data->rpm_output[1] = ret;
+
+	ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(0));
+	if (ret < 0)
+		goto out;
+	data->fan_fault[0] = ret;
+
+	ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(1));
+	if (ret < 0)
+		goto out;
+	data->fan_fault[1] = ret;
+
+	ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
+	if (ret < 0)
+		goto out;
+	data->config = ret;
+
+	ret = i2c_smbus_read_byte_data(client, TC654_REG_STATUS);
+	if (ret < 0)
+		goto out;
+	data->status = ret;
+
+	ret = i2c_smbus_read_byte_data(client, TC654_REG_DUTY_CYCLE);
+	if (ret < 0)
+		goto out;
+	data->duty_cycle = ret & 0x0f;
+
+	data->last_updated = jiffies;
+	data->valid = true;
+out:
+	mutex_unlock(&data->update_lock);
+
+	if (ret < 0)		/* upon error, encode it in return value */
+		data = ERR_PTR(ret);
+
+	return data;
+}
+
+/*
+ * sysfs attributes
+ */
+
+static ssize_t fan_show(struct device *dev, struct device_attribute *da,
+			char *buf)
+{
+	int nr = to_sensor_dev_attr(da)->index;
+	struct tc654_data *data = tc654_update_client(dev);
+	int val;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	if (data->config & TC654_REG_CONFIG_RES)
+		val = data->rpm_output[nr] * TC654_HIGH_RPM_RESOLUTION;
+	else
+		val = data->rpm_output[nr] * TC654_LOW_RPM_RESOLUTION;
+
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t fan_min_show(struct device *dev, struct device_attribute *da,
+			    char *buf)
+{
+	int nr = to_sensor_dev_attr(da)->index;
+	struct tc654_data *data = tc654_update_client(dev);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	return sprintf(buf, "%d\n",
+		       TC654_FAN_FAULT_FROM_REG(data->fan_fault[nr]));
+}
+
+static ssize_t fan_min_store(struct device *dev, struct device_attribute *da,
+			     const char *buf, size_t count)
+{
+	int nr = to_sensor_dev_attr(da)->index;
+	struct tc654_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long val;
+	int ret;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	val = clamp_val(val, 0, 12750);
+
+	mutex_lock(&data->update_lock);
+
+	data->fan_fault[nr] = TC654_FAN_FAULT_TO_REG(val);
+	ret = i2c_smbus_write_byte_data(client, TC654_REG_FAN_FAULT(nr),
+					data->fan_fault[nr]);
+
+	mutex_unlock(&data->update_lock);
+	return ret < 0 ? ret : count;
+}
+
+static ssize_t fan_alarm_show(struct device *dev, struct device_attribute *da,
+			      char *buf)
+{
+	int nr = to_sensor_dev_attr(da)->index;
+	struct tc654_data *data = tc654_update_client(dev);
+	int val;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	if (nr == 0)
+		val = !!(data->status & TC654_REG_STATUS_F1F);
+	else
+		val = !!(data->status & TC654_REG_STATUS_F2F);
+
+	return sprintf(buf, "%d\n", val);
+}
+
+static const u8 TC654_FAN_PULSE_SHIFT[] = { 1, 3 };
+
+static ssize_t fan_pulses_show(struct device *dev,
+			       struct device_attribute *da, char *buf)
+{
+	int nr = to_sensor_dev_attr(da)->index;
+	struct tc654_data *data = tc654_update_client(dev);
+	u8 val;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	val = BIT((data->config >> TC654_FAN_PULSE_SHIFT[nr]) & 0x03);
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t fan_pulses_store(struct device *dev,
+				struct device_attribute *da, const char *buf,
+				size_t count)
+{
+	int nr = to_sensor_dev_attr(da)->index;
+	struct tc654_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	u8 config;
+	unsigned long val;
+	int ret;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	switch (val) {
+	case 1:
+		config = 0;
+		break;
+	case 2:
+		config = 1;
+		break;
+	case 4:
+		config = 2;
+		break;
+	case 8:
+		config = 3;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	mutex_lock(&data->update_lock);
+
+	data->config &= ~(0x03 << TC654_FAN_PULSE_SHIFT[nr]);
+	data->config |= (config << TC654_FAN_PULSE_SHIFT[nr]);
+	ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
+
+	mutex_unlock(&data->update_lock);
+	return ret < 0 ? ret : count;
+}
+
+static ssize_t pwm_mode_show(struct device *dev, struct device_attribute *da,
+			     char *buf)
+{
+	struct tc654_data *data = tc654_update_client(dev);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	return sprintf(buf, "%d\n", !!(data->config & TC654_REG_CONFIG_DUTYC));
+}
+
+static ssize_t pwm_mode_store(struct device *dev, struct device_attribute *da,
+			      const char *buf, size_t count)
+{
+	struct tc654_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long val;
+	int ret;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	mutex_lock(&data->update_lock);
+
+	if (val)
+		data->config |= TC654_REG_CONFIG_DUTYC;
+	else
+		data->config &= ~TC654_REG_CONFIG_DUTYC;
+
+	ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
+
+	mutex_unlock(&data->update_lock);
+	return ret < 0 ? ret : count;
+}
+
+static const int tc654_pwm_map[16] = { 77,  88, 102, 112, 124, 136, 148, 160,
+				      172, 184, 196, 207, 219, 231, 243, 255};
+
+static ssize_t pwm_show(struct device *dev, struct device_attribute *da,
+			char *buf)
+{
+	struct tc654_data *data = tc654_update_client(dev);
+	int pwm;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	if (data->config & TC654_REG_CONFIG_SDM)
+		pwm = 0;
+	else
+		pwm = tc654_pwm_map[data->duty_cycle];
+
+	return sprintf(buf, "%d\n", pwm);
+}
+
+static int _set_pwm(struct tc654_data *data, unsigned long val)
+{
+	struct i2c_client *client = data->client;
+	int ret;
+
+	mutex_lock(&data->update_lock);
+
+	if (val == 0) {
+		data->config |= TC654_REG_CONFIG_SDM;
+		data->duty_cycle = 0;
+	} else {
+		data->config &= ~TC654_REG_CONFIG_SDM;
+		data->duty_cycle = val - 1;
+	}
+
+	ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
+	if (ret < 0)
+		goto out;
+
+	ret = i2c_smbus_write_byte_data(client, TC654_REG_DUTY_CYCLE,
+					data->duty_cycle);
+
+out:
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+static ssize_t pwm_store(struct device *dev, struct device_attribute *da,
+			 const char *buf, size_t count)
+{
+	struct tc654_data *data = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+	if (val > 255)
+		return -EINVAL;
+	if (val > 0)
+		val = find_closest(val, tc654_pwm_map, ARRAY_SIZE(tc654_pwm_map)) + 1;
+
+	ret = _set_pwm(data, val);
+	return ret < 0 ? ret : count;
+}
+
+static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, 0);
+static SENSOR_DEVICE_ATTR_RO(fan2_input, fan, 1);
+static SENSOR_DEVICE_ATTR_RW(fan1_min, fan_min, 0);
+static SENSOR_DEVICE_ATTR_RW(fan2_min, fan_min, 1);
+static SENSOR_DEVICE_ATTR_RO(fan1_alarm, fan_alarm, 0);
+static SENSOR_DEVICE_ATTR_RO(fan2_alarm, fan_alarm, 1);
+static SENSOR_DEVICE_ATTR_RW(fan1_pulses, fan_pulses, 0);
+static SENSOR_DEVICE_ATTR_RW(fan2_pulses, fan_pulses, 1);
+static SENSOR_DEVICE_ATTR_RW(pwm1_mode, pwm_mode, 0);
+static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
+
+/* Driver data */
+static struct attribute *tc654_attrs[] = {
+	&sensor_dev_attr_fan1_input.dev_attr.attr,
+	&sensor_dev_attr_fan2_input.dev_attr.attr,
+	&sensor_dev_attr_fan1_min.dev_attr.attr,
+	&sensor_dev_attr_fan2_min.dev_attr.attr,
+	&sensor_dev_attr_fan1_alarm.dev_attr.attr,
+	&sensor_dev_attr_fan2_alarm.dev_attr.attr,
+	&sensor_dev_attr_fan1_pulses.dev_attr.attr,
+	&sensor_dev_attr_fan2_pulses.dev_attr.attr,
+	&sensor_dev_attr_pwm1_mode.dev_attr.attr,
+	&sensor_dev_attr_pwm1.dev_attr.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(tc654);
+
+/*
+ * thermal cooling device functions
+ *
+ * Account for the "ShutDown Mode (SDM)" state by offsetting
+ * the 16 PWM duty cycle states by 1.
+ *
+ * State  0 =   0% PWM | Shutdown - Fan(s) are off
+ * State  1 =  30% PWM | duty_cycle =  0
+ * State  2 = ~35% PWM | duty_cycle =  1
+ * [...]
+ * State 15 = ~95% PWM | duty_cycle = 14
+ * State 16 = 100% PWM | duty_cycle = 15
+ */
+#define TC654_MAX_COOLING_STATE	16
+
+static int tc654_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state)
+{
+	*state = TC654_MAX_COOLING_STATE;
+	return 0;
+}
+
+static int tc654_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state)
+{
+	struct tc654_data *data = tc654_update_client(cdev->devdata);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	if (data->config & TC654_REG_CONFIG_SDM)
+		*state = 0;	/* FAN is off */
+	else
+		*state = data->duty_cycle + 1;	/* offset PWM States by 1 */
+
+	return 0;
+}
+
+static int tc654_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
+{
+	struct tc654_data *data = tc654_update_client(cdev->devdata);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	return _set_pwm(data, clamp_val(state, 0, TC654_MAX_COOLING_STATE));
+}
+
+static const struct thermal_cooling_device_ops tc654_fan_cool_ops = {
+	.get_max_state = tc654_get_max_state,
+	.get_cur_state = tc654_get_cur_state,
+	.set_cur_state = tc654_set_cur_state,
+};
+
+/*
+ * device probe and removal
+ */
+
+static int tc654_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct tc654_data *data;
+	struct device *hwmon_dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	data = devm_kzalloc(dev, sizeof(struct tc654_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	mutex_init(&data->update_lock);
+
+	ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
+	if (ret < 0)
+		return ret;
+
+	data->config = ret;
+
+	hwmon_dev =
+	    devm_hwmon_device_register_with_groups(dev, client->name, data,
+						   tc654_groups);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	if (IS_ENABLED(CONFIG_THERMAL)) {
+		struct thermal_cooling_device *cdev;
+
+		cdev = devm_thermal_of_child_cooling_device_register(dev, dev->of_node,
+								     client->name, hwmon_dev,
+								     &tc654_fan_cool_ops);
+		return PTR_ERR_OR_ZERO(cdev);
+	}
+
+	return 0;
+}
+
+static const struct i2c_device_id tc654_id[] = {
+	{ .name = "tc654" },
+	{ .name = "tc655" },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, tc654_id);
+
+static struct i2c_driver tc654_driver = {
+	.driver = {
+		   .name = "tc654",
+		   },
+	.probe = tc654_probe,
+	.id_table = tc654_id,
+};
+
+module_i2c_driver(tc654_driver);
+
+MODULE_AUTHOR("Allied Telesis Labs");
+MODULE_DESCRIPTION("Microchip TC654/TC655 driver");
+MODULE_LICENSE("GPL");