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, 879 insertions, 0 deletions

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
new file mode 100644
index 000000000..adbcb2c01
--- /dev/null
+++ b/drivers/thermal/thermal_sysfs.c
@@ -0,0 +1,879 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  thermal.c - sysfs interface of thermal devices
+ *
+ *  Copyright (C) 2016 Eduardo Valentin <edubezval@gmail.com>
+ *
+ *  Highly based on original thermal_core.c
+ *  Copyright (C) 2008 Intel Corp
+ *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
+ *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/container_of.h>
+#include <linux/sysfs.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/string_choices.h>
+#include <linux/jiffies.h>
+
+#include "thermal_core.h"
+
+/* sys I/F for thermal zone */
+
+static ssize_t
+type_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+	return sysfs_emit(buf, "%s\n", tz->type);
+}
+
+static ssize_t
+temp_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	int temperature, ret;
+
+	ret = thermal_zone_get_temp(tz, &temperature);
+
+	if (!ret)
+		return sysfs_emit(buf, "%d\n", temperature);
+
+	if (ret == -EAGAIN)
+		return -ENODATA;
+
+	return ret;
+}
+
+static ssize_t
+mode_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+	guard(thermal_zone)(tz);
+
+	return sysfs_emit(buf, "%s\n",
+		str_enabled_disabled(tz->mode == THERMAL_DEVICE_ENABLED));
+}
+
+static ssize_t
+mode_store(struct device *dev, struct device_attribute *attr,
+	   const char *buf, size_t count)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	int result;
+
+	if (!strncmp(buf, "enabled", sizeof("enabled") - 1))
+		result = thermal_zone_device_enable(tz);
+	else if (!strncmp(buf, "disabled", sizeof("disabled") - 1))
+		result = thermal_zone_device_disable(tz);
+	else
+		result = -EINVAL;
+
+	if (result)
+		return result;
+
+	return count;
+}
+
+#define thermal_trip_of_attr(_ptr_, _attr_)				\
+	({								\
+		struct thermal_trip_desc *td;				\
+									\
+		td = container_of(_ptr_, struct thermal_trip_desc,	\
+				  trip_attrs._attr_.attr);		\
+		&td->trip;						\
+	})
+
+static ssize_t
+trip_point_type_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
+{
+	struct thermal_trip *trip = thermal_trip_of_attr(attr, type);
+
+	return sysfs_emit(buf, "%s\n", thermal_trip_type_name(trip->type));
+}
+
+static ssize_t
+trip_point_temp_store(struct device *dev, struct device_attribute *attr,
+		      const char *buf, size_t count)
+{
+	struct thermal_trip *trip = thermal_trip_of_attr(attr, temp);
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	int temp;
+
+	if (kstrtoint(buf, 10, &temp))
+		return -EINVAL;
+
+	guard(thermal_zone)(tz);
+
+	if (temp == trip->temperature)
+		return count;
+
+	/* Arrange the condition to avoid integer overflows. */
+	if (temp != THERMAL_TEMP_INVALID &&
+	    temp <= trip->hysteresis + THERMAL_TEMP_INVALID)
+		return -EINVAL;
+
+	if (tz->ops.set_trip_temp) {
+		int ret;
+
+		ret = tz->ops.set_trip_temp(tz, trip, temp);
+		if (ret)
+			return ret;
+	}
+
+	thermal_zone_set_trip_temp(tz, trip, temp);
+
+	__thermal_zone_device_update(tz, THERMAL_TRIP_CHANGED);
+
+	return count;
+}
+
+static ssize_t
+trip_point_temp_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
+{
+	struct thermal_trip *trip = thermal_trip_of_attr(attr, temp);
+
+	return sysfs_emit(buf, "%d\n", READ_ONCE(trip->temperature));
+}
+
+static ssize_t
+trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
+		      const char *buf, size_t count)
+{
+	struct thermal_trip *trip = thermal_trip_of_attr(attr, hyst);
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	int hyst;
+
+	if (kstrtoint(buf, 10, &hyst) || hyst < 0)
+		return -EINVAL;
+
+	guard(thermal_zone)(tz);
+
+	if (hyst == trip->hysteresis)
+		return count;
+
+	/*
+	 * Allow the hysteresis to be updated when the temperature is invalid
+	 * to allow user space to avoid having to adjust hysteresis after a
+	 * valid temperature has been set, but in that case just change the
+	 * value and do nothing else.
+	 */
+	if (trip->temperature == THERMAL_TEMP_INVALID) {
+		WRITE_ONCE(trip->hysteresis, hyst);
+		return count;
+	}
+
+	if (trip->temperature - hyst <= THERMAL_TEMP_INVALID)
+		return -EINVAL;
+
+	thermal_zone_set_trip_hyst(tz, trip, hyst);
+
+	__thermal_zone_device_update(tz, THERMAL_TRIP_CHANGED);
+
+	return count;
+}
+
+static ssize_t
+trip_point_hyst_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
+{
+	struct thermal_trip *trip = thermal_trip_of_attr(attr, hyst);
+
+	return sysfs_emit(buf, "%d\n", READ_ONCE(trip->hysteresis));
+}
+
+static ssize_t
+policy_store(struct device *dev, struct device_attribute *attr,
+	     const char *buf, size_t count)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	char name[THERMAL_NAME_LENGTH];
+	int ret;
+
+	strscpy(name, buf);
+
+	ret = thermal_zone_device_set_policy(tz, name);
+	if (!ret)
+		ret = count;
+
+	return ret;
+}
+
+static ssize_t
+policy_show(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+	return sysfs_emit(buf, "%s\n", tz->governor->name);
+}
+
+static ssize_t
+available_policies_show(struct device *dev, struct device_attribute *devattr,
+			char *buf)
+{
+	return thermal_build_list_of_policies(buf);
+}
+
+#if (IS_ENABLED(CONFIG_THERMAL_EMULATION))
+static ssize_t
+emul_temp_store(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	int temperature;
+
+	if (kstrtoint(buf, 10, &temperature))
+		return -EINVAL;
+
+	guard(thermal_zone)(tz);
+
+	if (tz->ops.set_emul_temp) {
+		int ret;
+
+		ret = tz->ops.set_emul_temp(tz, temperature);
+		if (ret)
+			return ret;
+	} else {
+		tz->emul_temperature = temperature;
+	}
+
+	__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
+
+	return count;
+}
+static DEVICE_ATTR_WO(emul_temp);
+#endif
+
+static ssize_t
+sustainable_power_show(struct device *dev, struct device_attribute *devattr,
+		       char *buf)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+	if (tz->tzp)
+		return sysfs_emit(buf, "%u\n", tz->tzp->sustainable_power);
+	else
+		return -EIO;
+}
+
+static ssize_t
+sustainable_power_store(struct device *dev, struct device_attribute *devattr,
+			const char *buf, size_t count)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	u32 sustainable_power;
+
+	if (!tz->tzp)
+		return -EIO;
+
+	if (kstrtou32(buf, 10, &sustainable_power))
+		return -EINVAL;
+
+	tz->tzp->sustainable_power = sustainable_power;
+
+	return count;
+}
+
+#define create_s32_tzp_attr(name)					\
+	static ssize_t							\
+	name##_show(struct device *dev, struct device_attribute *devattr, \
+		char *buf)						\
+	{								\
+	struct thermal_zone_device *tz = to_thermal_zone(dev);		\
+									\
+	if (tz->tzp)							\
+		return sysfs_emit(buf, "%d\n", tz->tzp->name);		\
+	else								\
+		return -EIO;						\
+	}								\
+									\
+	static ssize_t							\
+	name##_store(struct device *dev, struct device_attribute *devattr, \
+		const char *buf, size_t count)				\
+	{								\
+		struct thermal_zone_device *tz = to_thermal_zone(dev);	\
+		s32 value;						\
+									\
+		if (!tz->tzp)						\
+			return -EIO;					\
+									\
+		if (kstrtos32(buf, 10, &value))				\
+			return -EINVAL;					\
+									\
+		tz->tzp->name = value;					\
+									\
+		return count;						\
+	}								\
+	static DEVICE_ATTR_RW(name)
+
+create_s32_tzp_attr(k_po);
+create_s32_tzp_attr(k_pu);
+create_s32_tzp_attr(k_i);
+create_s32_tzp_attr(k_d);
+create_s32_tzp_attr(integral_cutoff);
+create_s32_tzp_attr(slope);
+create_s32_tzp_attr(offset);
+#undef create_s32_tzp_attr
+
+/*
+ * These are thermal zone device attributes that will always be present.
+ * All the attributes created for tzp (create_s32_tzp_attr) also are always
+ * present on the sysfs interface.
+ */
+static DEVICE_ATTR_RO(type);
+static DEVICE_ATTR_RO(temp);
+static DEVICE_ATTR_RW(policy);
+static DEVICE_ATTR_RO(available_policies);
+static DEVICE_ATTR_RW(sustainable_power);
+
+/* These thermal zone device attributes are created based on conditions */
+static DEVICE_ATTR_RW(mode);
+
+/* These attributes are unconditionally added to a thermal zone */
+static struct attribute *thermal_zone_dev_attrs[] = {
+	&dev_attr_type.attr,
+	&dev_attr_temp.attr,
+#if (IS_ENABLED(CONFIG_THERMAL_EMULATION))
+	&dev_attr_emul_temp.attr,
+#endif
+	&dev_attr_policy.attr,
+	&dev_attr_available_policies.attr,
+	&dev_attr_sustainable_power.attr,
+	&dev_attr_k_po.attr,
+	&dev_attr_k_pu.attr,
+	&dev_attr_k_i.attr,
+	&dev_attr_k_d.attr,
+	&dev_attr_integral_cutoff.attr,
+	&dev_attr_slope.attr,
+	&dev_attr_offset.attr,
+	NULL,
+};
+
+static const struct attribute_group thermal_zone_attribute_group = {
+	.attrs = thermal_zone_dev_attrs,
+};
+
+static struct attribute *thermal_zone_mode_attrs[] = {
+	&dev_attr_mode.attr,
+	NULL,
+};
+
+static const struct attribute_group thermal_zone_mode_attribute_group = {
+	.attrs = thermal_zone_mode_attrs,
+};
+
+static const struct attribute_group *thermal_zone_attribute_groups[] = {
+	&thermal_zone_attribute_group,
+	&thermal_zone_mode_attribute_group,
+	/* This is not NULL terminated as we create the group dynamically */
+};
+
+/**
+ * create_trip_attrs() - create attributes for trip points
+ * @tz:		the thermal zone device
+ *
+ * helper function to instantiate sysfs entries for every trip
+ * point and its properties of a struct thermal_zone_device.
+ *
+ * Return: 0 on success, the proper error value otherwise.
+ */
+static int create_trip_attrs(struct thermal_zone_device *tz)
+{
+	struct thermal_trip_desc *td;
+	struct attribute **attrs;
+	int i;
+
+	attrs = kzalloc_objs(*attrs, tz->num_trips * 3 + 1);
+	if (!attrs)
+		return -ENOMEM;
+
+	i = 0;
+	for_each_trip_desc(tz, td) {
+		struct thermal_trip_attrs *trip_attrs = &td->trip_attrs;
+
+		/* create trip type attribute */
+		snprintf(trip_attrs->type.name, THERMAL_NAME_LENGTH,
+			 "trip_point_%d_type", i);
+
+		sysfs_attr_init(&trip_attrs->type.attr.attr);
+		trip_attrs->type.attr.attr.name = trip_attrs->type.name;
+		trip_attrs->type.attr.attr.mode = S_IRUGO;
+		trip_attrs->type.attr.show = trip_point_type_show;
+		attrs[i] = &trip_attrs->type.attr.attr;
+
+		/* create trip temp attribute */
+		snprintf(trip_attrs->temp.name, THERMAL_NAME_LENGTH,
+			 "trip_point_%d_temp", i);
+
+		sysfs_attr_init(&trip_attrs->temp.attr.attr);
+		trip_attrs->temp.attr.attr.name = trip_attrs->temp.name;
+		trip_attrs->temp.attr.attr.mode = S_IRUGO;
+		trip_attrs->temp.attr.show = trip_point_temp_show;
+		if (td->trip.flags & THERMAL_TRIP_FLAG_RW_TEMP) {
+			trip_attrs->temp.attr.attr.mode |= S_IWUSR;
+			trip_attrs->temp.attr.store = trip_point_temp_store;
+		}
+		attrs[i + tz->num_trips] = &trip_attrs->temp.attr.attr;
+
+		snprintf(trip_attrs->hyst.name, THERMAL_NAME_LENGTH,
+			 "trip_point_%d_hyst", i);
+
+		sysfs_attr_init(&trip_attrs->hyst.attr.attr);
+		trip_attrs->hyst.attr.attr.name = trip_attrs->hyst.name;
+		trip_attrs->hyst.attr.attr.mode = S_IRUGO;
+		trip_attrs->hyst.attr.show = trip_point_hyst_show;
+		if (td->trip.flags & THERMAL_TRIP_FLAG_RW_HYST) {
+			trip_attrs->hyst.attr.attr.mode |= S_IWUSR;
+			trip_attrs->hyst.attr.store = trip_point_hyst_store;
+		}
+		attrs[i + 2 * tz->num_trips] = &trip_attrs->hyst.attr.attr;
+		i++;
+	}
+	attrs[tz->num_trips * 3] = NULL;
+
+	tz->trips_attribute_group.attrs = attrs;
+
+	return 0;
+}
+
+/**
+ * destroy_trip_attrs() - destroy attributes for trip points
+ * @tz:		the thermal zone device
+ *
+ * helper function to free resources allocated by create_trip_attrs()
+ */
+static void destroy_trip_attrs(struct thermal_zone_device *tz)
+{
+	if (tz)
+		kfree(tz->trips_attribute_group.attrs);
+}
+
+int thermal_zone_create_device_groups(struct thermal_zone_device *tz)
+{
+	const struct attribute_group **groups;
+	int i, size, result;
+
+	/* we need one extra for trips and the NULL to terminate the array */
+	size = ARRAY_SIZE(thermal_zone_attribute_groups) + 2;
+	/* This also takes care of API requirement to be NULL terminated */
+	groups = kzalloc_objs(*groups, size);
+	if (!groups)
+		return -ENOMEM;
+
+	for (i = 0; i < size - 2; i++)
+		groups[i] = thermal_zone_attribute_groups[i];
+
+	if (tz->num_trips) {
+		result = create_trip_attrs(tz);
+		if (result) {
+			kfree(groups);
+
+			return result;
+		}
+
+		groups[size - 2] = &tz->trips_attribute_group;
+	}
+
+	tz->device.groups = groups;
+
+	return 0;
+}
+
+void thermal_zone_destroy_device_groups(struct thermal_zone_device *tz)
+{
+	if (!tz)
+		return;
+
+	if (tz->num_trips)
+		destroy_trip_attrs(tz);
+
+	kfree(tz->device.groups);
+}
+
+/* sys I/F for cooling device */
+static ssize_t
+cdev_type_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+
+	return sysfs_emit(buf, "%s\n", cdev->type);
+}
+
+static ssize_t max_state_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+
+	return sysfs_emit(buf, "%ld\n", cdev->max_state);
+}
+
+static ssize_t cur_state_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+	unsigned long state;
+	int ret;
+
+	ret = cdev->ops->get_cur_state(cdev, &state);
+	if (ret)
+		return ret;
+	return sysfs_emit(buf, "%ld\n", state);
+}
+
+static ssize_t
+cur_state_store(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+	unsigned long state;
+	int result;
+
+	result = kstrtoul(buf, 10, &state);
+	if (result < 0)
+		return result;
+
+	/* Requested state should be less than max_state + 1 */
+	if (state > cdev->max_state)
+		return -EINVAL;
+
+	guard(cooling_dev)(cdev);
+
+	result = cdev->ops->set_cur_state(cdev, state);
+	if (result)
+		return result;
+
+	thermal_cooling_device_stats_update(cdev, state);
+
+	return count;
+}
+
+static struct device_attribute
+dev_attr_cdev_type = __ATTR(type, 0444, cdev_type_show, NULL);
+static DEVICE_ATTR_RO(max_state);
+static DEVICE_ATTR_RW(cur_state);
+
+static struct attribute *cooling_device_attrs[] = {
+	&dev_attr_cdev_type.attr,
+	&dev_attr_max_state.attr,
+	&dev_attr_cur_state.attr,
+	NULL,
+};
+
+static const struct attribute_group cooling_device_attr_group = {
+	.attrs = cooling_device_attrs,
+};
+
+static const struct attribute_group *cooling_device_attr_groups[] = {
+	&cooling_device_attr_group,
+	NULL, /* Space allocated for cooling_device_stats_attr_group */
+	NULL,
+};
+
+#ifdef CONFIG_THERMAL_STATISTICS
+struct cooling_dev_stats {
+	spinlock_t lock;
+	unsigned int total_trans;
+	unsigned long state;
+	ktime_t last_time;
+	ktime_t *time_in_state;
+	unsigned int *trans_table;
+};
+
+static void update_time_in_state(struct cooling_dev_stats *stats)
+{
+	ktime_t now = ktime_get(), delta;
+
+	delta = ktime_sub(now, stats->last_time);
+	stats->time_in_state[stats->state] =
+		ktime_add(stats->time_in_state[stats->state], delta);
+	stats->last_time = now;
+}
+
+void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
+					 unsigned long new_state)
+{
+	struct cooling_dev_stats *stats = cdev->stats;
+
+	lockdep_assert_held(&cdev->lock);
+
+	if (!stats)
+		return;
+
+	spin_lock(&stats->lock);
+
+	if (stats->state == new_state)
+		goto unlock;
+
+	update_time_in_state(stats);
+	stats->trans_table[stats->state * (cdev->max_state + 1) + new_state]++;
+	stats->state = new_state;
+	stats->total_trans++;
+
+unlock:
+	spin_unlock(&stats->lock);
+}
+
+static ssize_t total_trans_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+	struct cooling_dev_stats *stats;
+	int ret;
+
+	guard(cooling_dev)(cdev);
+
+	stats = cdev->stats;
+	if (!stats)
+		return 0;
+
+	spin_lock(&stats->lock);
+	ret = sysfs_emit(buf, "%u\n", stats->total_trans);
+	spin_unlock(&stats->lock);
+
+	return ret;
+}
+
+static ssize_t
+time_in_state_ms_show(struct device *dev, struct device_attribute *attr,
+		      char *buf)
+{
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+	struct cooling_dev_stats *stats;
+	ssize_t len = 0;
+	int i;
+
+	guard(cooling_dev)(cdev);
+
+	stats = cdev->stats;
+	if (!stats)
+		return 0;
+
+	spin_lock(&stats->lock);
+
+	update_time_in_state(stats);
+
+	for (i = 0; i <= cdev->max_state; i++) {
+		len += sysfs_emit_at(buf, len, "state%u\t%llu\n", i,
+				     ktime_to_ms(stats->time_in_state[i]));
+	}
+	spin_unlock(&stats->lock);
+
+	return len;
+}
+
+static ssize_t
+reset_store(struct device *dev, struct device_attribute *attr, const char *buf,
+	    size_t count)
+{
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+	struct cooling_dev_stats *stats;
+	int i, states;
+
+	guard(cooling_dev)(cdev);
+
+	stats = cdev->stats;
+	if (!stats)
+		return count;
+
+	states = cdev->max_state + 1;
+
+	spin_lock(&stats->lock);
+
+	stats->total_trans = 0;
+	stats->last_time = ktime_get();
+	memset(stats->trans_table, 0,
+	       states * states * sizeof(*stats->trans_table));
+
+	for (i = 0; i < states; i++)
+		stats->time_in_state[i] = ktime_set(0, 0);
+
+	spin_unlock(&stats->lock);
+
+	return count;
+}
+
+static ssize_t trans_table_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+	struct cooling_dev_stats *stats;
+	ssize_t len = 0;
+	int i, j, copied;
+
+	guard(cooling_dev)(cdev);
+
+	stats = cdev->stats;
+	if (!stats)
+		return -ENODATA;
+
+	len += sysfs_emit_at(buf, len, " From  :    To\n");
+	len += sysfs_emit_at(buf, len, "       : ");
+	for (i = 0; i <= cdev->max_state; i++) {
+		copied = sysfs_emit_at(buf, len, "state%2u  ", i);
+		if (!copied)
+			goto buf_full;
+		len += copied;
+	}
+	len += sysfs_emit_at(buf, len, "\n");
+
+	for (i = 0; i <= cdev->max_state; i++) {
+		copied = sysfs_emit_at(buf, len, "state%2u:", i);
+		if (!copied)
+			goto buf_full;
+		len += copied;
+
+		for (j = 0; j <= cdev->max_state; j++) {
+			copied = sysfs_emit_at(buf, len, "%8u ",
+				stats->trans_table[i * (cdev->max_state + 1) + j]);
+			if (!copied)
+				goto buf_full;
+			len += copied;
+		}
+		copied = sysfs_emit_at(buf, len, "\n");
+		if (!copied)
+			goto buf_full;
+		len += copied;
+	}
+
+	return len;
+
+buf_full:
+	pr_warn_once("Thermal transition table exceeds PAGE_SIZE. Disabling\n");
+	return -EFBIG;
+}
+
+static DEVICE_ATTR_RO(total_trans);
+static DEVICE_ATTR_RO(time_in_state_ms);
+static DEVICE_ATTR_WO(reset);
+static DEVICE_ATTR_RO(trans_table);
+
+static struct attribute *cooling_device_stats_attrs[] = {
+	&dev_attr_total_trans.attr,
+	&dev_attr_time_in_state_ms.attr,
+	&dev_attr_reset.attr,
+	&dev_attr_trans_table.attr,
+	NULL
+};
+
+static const struct attribute_group cooling_device_stats_attr_group = {
+	.attrs = cooling_device_stats_attrs,
+	.name = "stats"
+};
+
+static void cooling_device_stats_setup(struct thermal_cooling_device *cdev)
+{
+	const struct attribute_group *stats_attr_group = NULL;
+	struct cooling_dev_stats *stats;
+	/* Total number of states is highest state + 1 */
+	unsigned long states = cdev->max_state + 1;
+	int var;
+
+	var = sizeof(*stats);
+	var += sizeof(*stats->time_in_state) * states;
+	var += sizeof(*stats->trans_table) * states * states;
+
+	stats = kzalloc(var, GFP_KERNEL);
+	if (!stats)
+		goto out;
+
+	stats->time_in_state = (ktime_t *)(stats + 1);
+	stats->trans_table = (unsigned int *)(stats->time_in_state + states);
+	cdev->stats = stats;
+	stats->last_time = ktime_get();
+
+	spin_lock_init(&stats->lock);
+
+	stats_attr_group = &cooling_device_stats_attr_group;
+
+out:
+	/* Fill the empty slot left in cooling_device_attr_groups */
+	var = ARRAY_SIZE(cooling_device_attr_groups) - 2;
+	cooling_device_attr_groups[var] = stats_attr_group;
+}
+
+static void cooling_device_stats_destroy(struct thermal_cooling_device *cdev)
+{
+	kfree(cdev->stats);
+	cdev->stats = NULL;
+}
+
+#else
+
+static inline void
+cooling_device_stats_setup(struct thermal_cooling_device *cdev) {}
+static inline void
+cooling_device_stats_destroy(struct thermal_cooling_device *cdev) {}
+
+#endif /* CONFIG_THERMAL_STATISTICS */
+
+void thermal_cooling_device_setup_sysfs(struct thermal_cooling_device *cdev)
+{
+	cooling_device_stats_setup(cdev);
+	cdev->device.groups = cooling_device_attr_groups;
+}
+
+void thermal_cooling_device_destroy_sysfs(struct thermal_cooling_device *cdev)
+{
+	cooling_device_stats_destroy(cdev);
+}
+
+void thermal_cooling_device_stats_reinit(struct thermal_cooling_device *cdev)
+{
+	lockdep_assert_held(&cdev->lock);
+
+	cooling_device_stats_destroy(cdev);
+	cooling_device_stats_setup(cdev);
+}
+
+/* these helper will be used only at the time of bindig */
+ssize_t
+trip_point_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	struct thermal_instance *instance;
+
+	instance = container_of(attr, struct thermal_instance, attr);
+
+	return sysfs_emit(buf, "%d\n", thermal_zone_trip_id(tz, instance->trip));
+}
+
+ssize_t
+weight_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct thermal_instance *instance;
+
+	instance = container_of(attr, struct thermal_instance, weight_attr);
+
+	return sysfs_emit(buf, "%d\n", instance->weight);
+}
+
+ssize_t weight_store(struct device *dev, struct device_attribute *attr,
+		     const char *buf, size_t count)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	struct thermal_instance *instance;
+	int ret, weight;
+
+	ret = kstrtoint(buf, 0, &weight);
+	if (ret)
+		return ret;
+
+	instance = container_of(attr, struct thermal_instance, weight_attr);
+
+	/* Don't race with governors using the 'weight' value */
+	guard(thermal_zone)(tz);
+
+	instance->weight = weight;
+
+	thermal_governor_update_tz(tz, THERMAL_INSTANCE_WEIGHT_CHANGED);
+
+	return count;
+}