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, 536 insertions, 0 deletions

diff --git a/drivers/iio/light/zopt2201.c b/drivers/iio/light/zopt2201.c
new file mode 100644
index 000000000..b53be5f73
--- /dev/null
+++ b/drivers/iio/light/zopt2201.c
@@ -0,0 +1,536 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * zopt2201.c - Support for IDT ZOPT2201 ambient light and UV B sensor
+ *
+ * Copyright 2017 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
+ *
+ * Datasheet: https://www.idt.com/document/dst/zopt2201-datasheet
+ * 7-bit I2C slave addresses 0x53 (default) or 0x52 (programmed)
+ *
+ * TODO: interrupt support, ALS/UVB raw mode
+ */
+
+#include <linux/cleanup.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/unaligned.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define ZOPT2201_DRV_NAME "zopt2201"
+
+/* Registers */
+#define ZOPT2201_MAIN_CTRL		0x00
+#define ZOPT2201_LS_MEAS_RATE		0x04
+#define ZOPT2201_LS_GAIN		0x05
+#define ZOPT2201_PART_ID		0x06
+#define ZOPT2201_MAIN_STATUS		0x07
+#define ZOPT2201_ALS_DATA		0x0d /* LSB first, 13 to 20 bits */
+#define ZOPT2201_UVB_DATA		0x10 /* LSB first, 13 to 20 bits */
+#define ZOPT2201_UV_COMP_DATA		0x13 /* LSB first, 13 to 20 bits */
+#define ZOPT2201_COMP_DATA		0x16 /* LSB first, 13 to 20 bits */
+#define ZOPT2201_INT_CFG		0x19
+#define ZOPT2201_INT_PST		0x1a
+
+#define ZOPT2201_MAIN_CTRL_LS_MODE	BIT(3) /* 0 .. ALS, 1 .. UV B */
+#define ZOPT2201_MAIN_CTRL_LS_EN	BIT(1)
+
+/* Values for ZOPT2201_LS_MEAS_RATE resolution / bit width */
+#define ZOPT2201_MEAS_RES_20BIT		0 /* takes 400 ms */
+#define ZOPT2201_MEAS_RES_19BIT		1 /* takes 200 ms */
+#define ZOPT2201_MEAS_RES_18BIT		2 /* takes 100 ms, default */
+#define ZOPT2201_MEAS_RES_17BIT		3 /* takes 50 ms */
+#define ZOPT2201_MEAS_RES_16BIT		4 /* takes 25 ms */
+#define ZOPT2201_MEAS_RES_13BIT		5 /* takes 3.125 ms */
+#define ZOPT2201_MEAS_RES_SHIFT		4
+
+/* Values for ZOPT2201_LS_MEAS_RATE measurement rate */
+#define ZOPT2201_MEAS_FREQ_25MS		0
+#define ZOPT2201_MEAS_FREQ_50MS		1
+#define ZOPT2201_MEAS_FREQ_100MS	2 /* default */
+#define ZOPT2201_MEAS_FREQ_200MS	3
+#define ZOPT2201_MEAS_FREQ_500MS	4
+#define ZOPT2201_MEAS_FREQ_1000MS	5
+#define ZOPT2201_MEAS_FREQ_2000MS	6
+
+/* Values for ZOPT2201_LS_GAIN */
+#define ZOPT2201_LS_GAIN_1		0
+#define ZOPT2201_LS_GAIN_3		1
+#define ZOPT2201_LS_GAIN_6		2
+#define ZOPT2201_LS_GAIN_9		3
+#define ZOPT2201_LS_GAIN_18		4
+
+/* Values for ZOPT2201_MAIN_STATUS */
+#define ZOPT2201_MAIN_STATUS_POWERON	BIT(5)
+#define ZOPT2201_MAIN_STATUS_INT	BIT(4)
+#define ZOPT2201_MAIN_STATUS_DRDY	BIT(3)
+
+#define ZOPT2201_PART_NUMBER		0xb2
+
+struct zopt2201_data {
+	struct i2c_client *client;
+	struct mutex lock;
+	u8 gain;
+	u8 res;
+	u8 rate;
+};
+
+static const struct {
+	unsigned int gain; /* gain factor */
+	unsigned int scale; /* micro lux per count */
+} zopt2201_gain_als[] = {
+	{  1, 19200000 },
+	{  3,  6400000 },
+	{  6,  3200000 },
+	{  9,  2133333 },
+	{ 18,  1066666 },
+};
+
+static const struct {
+	unsigned int gain; /* gain factor */
+	unsigned int scale; /* micro W/m2 per count */
+} zopt2201_gain_uvb[] = {
+	{  1, 460800 },
+	{  3, 153600 },
+	{  6,  76800 },
+	{  9,  51200 },
+	{ 18,  25600 },
+};
+
+static const struct {
+	unsigned int bits; /* sensor resolution in bits */
+	unsigned long us; /* measurement time in micro seconds */
+} zopt2201_resolution[] = {
+	{ 20, 400000 },
+	{ 19, 200000 },
+	{ 18, 100000 },
+	{ 17,  50000 },
+	{ 16,  25000 },
+	{ 13,   3125 },
+};
+
+struct zopt2201_scale {
+	unsigned int scale, uscale; /* scale factor as integer + micro */
+	u8 gain; /* gain register value */
+	u8 res; /* resolution register value */
+};
+
+static const struct zopt2201_scale zopt2201_scale_als[] = {
+	{ 19, 200000, 0, 5 },
+	{  6, 400000, 1, 5 },
+	{  3, 200000, 2, 5 },
+	{  2, 400000, 0, 4 },
+	{  2, 133333, 3, 5 },
+	{  1, 200000, 0, 3 },
+	{  1,  66666, 4, 5 },
+	{  0, 800000, 1, 4 },
+	{  0, 600000, 0, 2 },
+	{  0, 400000, 2, 4 },
+	{  0, 300000, 0, 1 },
+	{  0, 266666, 3, 4 },
+	{  0, 200000, 2, 3 },
+	{  0, 150000, 0, 0 },
+	{  0, 133333, 4, 4 },
+	{  0, 100000, 2, 2 },
+	{  0,  66666, 4, 3 },
+	{  0,  50000, 2, 1 },
+	{  0,  33333, 4, 2 },
+	{  0,  25000, 2, 0 },
+	{  0,  16666, 4, 1 },
+	{  0,   8333, 4, 0 },
+};
+
+static const struct zopt2201_scale zopt2201_scale_uvb[] = {
+	{ 0, 460800, 0, 5 },
+	{ 0, 153600, 1, 5 },
+	{ 0,  76800, 2, 5 },
+	{ 0,  57600, 0, 4 },
+	{ 0,  51200, 3, 5 },
+	{ 0,  28800, 0, 3 },
+	{ 0,  25600, 4, 5 },
+	{ 0,  19200, 1, 4 },
+	{ 0,  14400, 0, 2 },
+	{ 0,   9600, 2, 4 },
+	{ 0,   7200, 0, 1 },
+	{ 0,   6400, 3, 4 },
+	{ 0,   4800, 2, 3 },
+	{ 0,   3600, 0, 0 },
+	{ 0,   3200, 4, 4 },
+	{ 0,   2400, 2, 2 },
+	{ 0,   1600, 4, 3 },
+	{ 0,   1200, 2, 1 },
+	{ 0,    800, 4, 2 },
+	{ 0,    600, 2, 0 },
+	{ 0,    400, 4, 1 },
+	{ 0,    200, 4, 0 },
+};
+
+static int zopt2201_enable_mode(struct zopt2201_data *data, bool uvb_mode)
+{
+	u8 out = ZOPT2201_MAIN_CTRL_LS_EN;
+
+	if (uvb_mode)
+		out |= ZOPT2201_MAIN_CTRL_LS_MODE;
+
+	return i2c_smbus_write_byte_data(data->client, ZOPT2201_MAIN_CTRL, out);
+}
+
+static int zopt2201_read(struct zopt2201_data *data, u8 reg)
+{
+	struct i2c_client *client = data->client;
+	int tries = 10;
+	u8 buf[3];
+	int ret;
+
+	guard(mutex)(&data->lock);
+	ret = zopt2201_enable_mode(data, reg == ZOPT2201_UVB_DATA);
+	if (ret < 0)
+		return ret;
+
+	while (tries--) {
+		unsigned long t = zopt2201_resolution[data->res].us;
+
+		if (t <= 20000)
+			usleep_range(t, t + 1000);
+		else
+			msleep(t / 1000);
+		ret = i2c_smbus_read_byte_data(client, ZOPT2201_MAIN_STATUS);
+		if (ret < 0)
+			return ret;
+		if (ret & ZOPT2201_MAIN_STATUS_DRDY)
+			break;
+	}
+
+	if (tries < 0) {
+		ret = -ETIMEDOUT;
+		return ret;
+	}
+
+	ret = i2c_smbus_read_i2c_block_data(client, reg, sizeof(buf), buf);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(client, ZOPT2201_MAIN_CTRL, 0x00);
+	if (ret < 0)
+		return ret;
+
+	return get_unaligned_le24(&buf[0]);
+}
+
+static const struct iio_chan_spec zopt2201_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.address = ZOPT2201_ALS_DATA,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_LIGHT_UV,
+		.address = ZOPT2201_UVB_DATA,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+	},
+	{
+		.type = IIO_UVINDEX,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+	},
+};
+
+static int zopt2201_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct zopt2201_data *data = iio_priv(indio_dev);
+	u64 tmp;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = zopt2201_read(data, chan->address);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_PROCESSED:
+		ret = zopt2201_read(data, ZOPT2201_UVB_DATA);
+		if (ret < 0)
+			return ret;
+		*val = ret * 18 *
+			(1 << (20 - zopt2201_resolution[data->res].bits)) /
+			zopt2201_gain_uvb[data->gain].gain;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->address) {
+		case ZOPT2201_ALS_DATA:
+			*val = zopt2201_gain_als[data->gain].scale;
+			break;
+		case ZOPT2201_UVB_DATA:
+			*val = zopt2201_gain_uvb[data->gain].scale;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		*val2 = 1000000;
+		*val2 *= (1 << (zopt2201_resolution[data->res].bits - 13));
+		tmp = div_s64(*val * 1000000ULL, *val2);
+		*val = div_s64_rem(tmp, 1000000, val2);
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_INT_TIME:
+		*val = 0;
+		*val2 = zopt2201_resolution[data->res].us;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int zopt2201_set_resolution(struct zopt2201_data *data, u8 res)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, ZOPT2201_LS_MEAS_RATE,
+					(res << ZOPT2201_MEAS_RES_SHIFT) |
+					data->rate);
+	if (ret < 0)
+		return ret;
+
+	data->res = res;
+
+	return 0;
+}
+
+static int zopt2201_write_resolution(struct zopt2201_data *data,
+				     int val, int val2)
+{
+	int i;
+
+	if (val != 0)
+		return -EINVAL;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_resolution); i++)
+		if (val2 == zopt2201_resolution[i].us) {
+			guard(mutex)(&data->lock);
+			return zopt2201_set_resolution(data, i);
+		}
+
+	return -EINVAL;
+}
+
+static int zopt2201_set_gain(struct zopt2201_data *data, u8 gain)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, ZOPT2201_LS_GAIN, gain);
+	if (ret < 0)
+		return ret;
+
+	data->gain = gain;
+
+	return 0;
+}
+
+static int zopt2201_write_scale_by_idx(struct zopt2201_data *data, int idx,
+				       const struct zopt2201_scale *zopt2201_scale_array)
+{
+	int ret;
+
+	guard(mutex)(&data->lock);
+	ret = zopt2201_set_resolution(data, zopt2201_scale_array[idx].res);
+	if (ret < 0)
+		return ret;
+
+	return zopt2201_set_gain(data, zopt2201_scale_array[idx].gain);
+}
+
+static int zopt2201_write_scale_als(struct zopt2201_data *data,
+				     int val, int val2)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_scale_als); i++)
+		if (val == zopt2201_scale_als[i].scale &&
+		    val2 == zopt2201_scale_als[i].uscale)
+			return zopt2201_write_scale_by_idx(data, i, zopt2201_scale_als);
+
+	return -EINVAL;
+}
+
+static int zopt2201_write_scale_uvb(struct zopt2201_data *data,
+				     int val, int val2)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_scale_uvb); i++)
+		if (val == zopt2201_scale_uvb[i].scale &&
+		    val2 == zopt2201_scale_uvb[i].uscale)
+			return zopt2201_write_scale_by_idx(data, i, zopt2201_scale_uvb);
+
+	return -EINVAL;
+}
+
+static int zopt2201_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int val, int val2, long mask)
+{
+	struct zopt2201_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		return zopt2201_write_resolution(data, val, val2);
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->address) {
+		case ZOPT2201_ALS_DATA:
+			return zopt2201_write_scale_als(data, val, val2);
+		case ZOPT2201_UVB_DATA:
+			return zopt2201_write_scale_uvb(data, val, val2);
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t zopt2201_show_int_time_available(struct device *dev,
+						struct device_attribute *attr,
+						char *buf)
+{
+	size_t len = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_resolution); i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06lu ",
+				 zopt2201_resolution[i].us);
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static IIO_DEV_ATTR_INT_TIME_AVAIL(zopt2201_show_int_time_available);
+
+static ssize_t zopt2201_show_als_scale_avail(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	ssize_t len = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_scale_als); i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ",
+				 zopt2201_scale_als[i].scale,
+				 zopt2201_scale_als[i].uscale);
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static ssize_t zopt2201_show_uvb_scale_avail(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	ssize_t len = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_scale_uvb); i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ",
+				 zopt2201_scale_uvb[i].scale,
+				 zopt2201_scale_uvb[i].uscale);
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(in_illuminance_scale_available, 0444,
+		       zopt2201_show_als_scale_avail, NULL, 0);
+static IIO_DEVICE_ATTR(in_intensity_uv_scale_available, 0444,
+		       zopt2201_show_uvb_scale_avail, NULL, 0);
+
+static struct attribute *zopt2201_attributes[] = {
+	&iio_dev_attr_integration_time_available.dev_attr.attr,
+	&iio_dev_attr_in_illuminance_scale_available.dev_attr.attr,
+	&iio_dev_attr_in_intensity_uv_scale_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group zopt2201_attribute_group = {
+	.attrs = zopt2201_attributes,
+};
+
+static const struct iio_info zopt2201_info = {
+	.read_raw = zopt2201_read_raw,
+	.write_raw = zopt2201_write_raw,
+	.attrs = &zopt2201_attribute_group,
+};
+
+static int zopt2201_probe(struct i2c_client *client)
+{
+	struct zopt2201_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+		return -EOPNOTSUPP;
+
+	ret = i2c_smbus_read_byte_data(client, ZOPT2201_PART_ID);
+	if (ret < 0)
+		return ret;
+	if (ret != ZOPT2201_PART_NUMBER)
+		return -ENODEV;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+	mutex_init(&data->lock);
+
+	indio_dev->info = &zopt2201_info;
+	indio_dev->channels = zopt2201_channels;
+	indio_dev->num_channels = ARRAY_SIZE(zopt2201_channels);
+	indio_dev->name = ZOPT2201_DRV_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	data->rate = ZOPT2201_MEAS_FREQ_100MS;
+	ret = zopt2201_set_resolution(data, ZOPT2201_MEAS_RES_18BIT);
+	if (ret < 0)
+		return ret;
+
+	ret = zopt2201_set_gain(data, ZOPT2201_LS_GAIN_3);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id zopt2201_id[] = {
+	{ .name = "zopt2201" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, zopt2201_id);
+
+static struct i2c_driver zopt2201_driver = {
+	.driver = {
+		.name   = ZOPT2201_DRV_NAME,
+	},
+	.probe = zopt2201_probe,
+	.id_table = zopt2201_id,
+};
+
+module_i2c_driver(zopt2201_driver);
+
+MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("IDT ZOPT2201 ambient light and UV B sensor driver");
+MODULE_LICENSE("GPL");