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, 402 insertions, 0 deletions

diff --git a/drivers/iio/amplifiers/ad8366.c b/drivers/iio/amplifiers/ad8366.c
new file mode 100644
index 000000000..e12f8604f
--- /dev/null
+++ b/drivers/iio/amplifiers/ad8366.c
@@ -0,0 +1,402 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AD8366 and similar Gain Amplifiers
+ * This driver supports the following gain amplifiers:
+ *   AD8366 Dual-Digital Variable Gain Amplifier (VGA)
+ *   ADA4961 BiCMOS RF Digital Gain Amplifier (DGA)
+ *   ADL5240 Digitally controlled variable gain amplifier (VGA)
+ *   ADRF5702: 0.125 dB LSB, 8-Bit, Silicon Digital Attenuator, 50 MHz to 20 GHz
+ *   ADRF5703: 0.25 dB LSB, 7-Bit, Silicon Digital Attenuator, 9 kHz to 20 GHz
+ *   ADRF5720: 0.5 dB LSB, 6-Bit, Silicon Digital Attenuator, 9 kHz to 40 GHz
+ *   ADRF5730: 0.5 dB LSB, 6-Bit, Silicon Digital Attenuator, 100 MHz to 40 GHz
+ *   ADRF5731: 2 dB LSB, 4-Bit, Silicon Digital Attenuator, 100 MHz to 40 GHz
+ *   HMC271A: 1dB LSB 5-Bit Digital Attenuator SMT, 0.7 - 3.7 GHz
+ *   HMC792A 0.25 dB LSB GaAs MMIC 6-Bit Digital Attenuator
+ *   HMC1018A: 1.0 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz
+ *   HMC1019A: 0.5 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz
+ *   HMC1119 0.25 dB LSB, 7-Bit, Silicon Digital Attenuator
+ *
+ * Copyright 2012-2026 Analog Devices Inc.
+ */
+
+#include <linux/bitrev.h>
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/math.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+#include <linux/unaligned.h>
+
+#include <linux/iio/iio.h>
+
+struct ad8366_info {
+	const char *name;
+	int gain_min;
+	int gain_max;
+	int gain_step;
+	size_t num_channels;
+	size_t (*pack_code)(const unsigned char *code, size_t num_channels,
+			    unsigned char *data);
+};
+
+struct ad8366_state {
+	struct spi_device	*spi;
+	struct mutex            lock; /* protect sensor state */
+	unsigned char		ch[2];
+	const struct ad8366_info *info;
+	/*
+	 * DMA (thus cache coherency maintenance) may require the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	unsigned char		data[2] __aligned(IIO_DMA_MINALIGN);
+};
+
+static size_t ad8366_pack_code(const unsigned char *code, size_t num_channels,
+			       unsigned char *data)
+{
+	u8 ch_a = bitrev8(code[0]) >> 2;
+	u8 ch_b = bitrev8(code[1]) >> 2;
+
+	put_unaligned_be16((ch_b << 6) | ch_a, &data[0]);
+	return sizeof(__be16);
+}
+
+static size_t adrf5731_pack_code(const unsigned char *code, size_t num_channels,
+				 unsigned char *data)
+{
+	data[0] = code[0] << 2;
+	return 1;
+}
+
+static size_t hmc271_pack_code(const unsigned char *code, size_t num_channels,
+			       unsigned char *data)
+{
+	data[0] = bitrev8(code[0]) >> 3;
+	return 1;
+}
+
+static const struct ad8366_info ad8366_chip_info = {
+	.name = "ad8366",
+	.gain_min = 4500,
+	.gain_max = 20500,
+	.gain_step = 253,
+	.num_channels = 2,
+	.pack_code = ad8366_pack_code,
+};
+
+static const struct ad8366_info ada4961_chip_info = {
+	.name = "ada4961",
+	.gain_min = -6000,
+	.gain_max = 15000,
+	.gain_step = -1000,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info adl5240_chip_info = {
+	.name = "adl5240",
+	.gain_min = -11500,
+	.gain_max = 20000,
+	.gain_step = 500,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info adrf5702_chip_info = {
+	.name = "adrf5702",
+	.gain_min = -31875,
+	.gain_max = 0,
+	.gain_step = -125,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info adrf5703_chip_info = {
+	.name = "adrf5703",
+	.gain_min = -31750,
+	.gain_max = 0,
+	.gain_step = -250,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info adrf5720_chip_info = {
+	.name = "adrf5720",
+	.gain_min = -31500,
+	.gain_max = 0,
+	.gain_step = -500,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info adrf5730_chip_info = {
+	.name = "adrf5730",
+	.gain_min = -31500,
+	.gain_max = 0,
+	.gain_step = -500,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info adrf5731_chip_info = {
+	.name = "adrf5731",
+	.gain_min = -30000,
+	.gain_max = 0,
+	.gain_step = -2000,
+	.num_channels = 1,
+	.pack_code = adrf5731_pack_code,
+};
+
+static const struct ad8366_info hmc271_chip_info = {
+	.name = "hmc271a",
+	.gain_min = -31000,
+	.gain_max = 0,
+	.gain_step = 1000,
+	.num_channels = 1,
+	.pack_code = hmc271_pack_code,
+};
+
+static const struct ad8366_info hmc792_chip_info = {
+	.name = "hmc792a",
+	.gain_min = -15750,
+	.gain_max = 0,
+	.gain_step = 250,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info hmc1018_chip_info = {
+	.name = "hmc1018a",
+	.gain_min = -31000,
+	.gain_max = 0,
+	.gain_step = 1000,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info hmc1019_chip_info = {
+	.name = "hmc1019a",
+	.gain_min = -15500,
+	.gain_max = 0,
+	.gain_step = 500,
+	.num_channels = 1,
+};
+
+static const struct ad8366_info hmc1119_chip_info = {
+	.name = "hmc1119",
+	.gain_min = -31750,
+	.gain_max = 0,
+	.gain_step = -250,
+	.num_channels = 1,
+};
+
+static int ad8366_write_code(struct ad8366_state *st)
+{
+	const struct ad8366_info *inf = st->info;
+	size_t len = 1;
+
+	if (inf->pack_code)
+		len = inf->pack_code(st->ch, inf->num_channels, st->data);
+	else
+		st->data[0] = st->ch[0];
+
+	return spi_write(st->spi, st->data, len);
+}
+
+static int ad8366_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	struct ad8366_state *st = iio_priv(indio_dev);
+	const struct ad8366_info *inf = st->info;
+	int ret;
+	int code, gain = 0;
+
+	mutex_lock(&st->lock);
+	switch (m) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		code = st->ch[chan->channel];
+		gain = inf->gain_step > 0 ? inf->gain_min : inf->gain_max;
+		gain += inf->gain_step * code;
+		/* Values in dB */
+		*val = gain / 1000;
+		*val2 = (gain % 1000) * 1000;
+
+		ret = IIO_VAL_INT_PLUS_MICRO_DB;
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	mutex_unlock(&st->lock);
+
+	return ret;
+};
+
+static int ad8366_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val,
+			    int val2,
+			    long mask)
+{
+	struct ad8366_state *st = iio_priv(indio_dev);
+	const struct ad8366_info *inf = st->info;
+	int code = 0, gain;
+	int ret;
+
+	/* Values in dB */
+	if (val < 0)
+		gain = (val * 1000) - (val2 / 1000);
+	else
+		gain = (val * 1000) + (val2 / 1000);
+
+	if (gain > inf->gain_max || gain < inf->gain_min)
+		return -EINVAL;
+
+	gain -= inf->gain_step > 0 ? inf->gain_min : inf->gain_max;
+	code = DIV_ROUND_CLOSEST(gain, inf->gain_step);
+
+	mutex_lock(&st->lock);
+	switch (mask) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		st->ch[chan->channel] = code;
+		ret = ad8366_write_code(st);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	mutex_unlock(&st->lock);
+
+	return ret;
+}
+
+static int ad8366_write_raw_get_fmt(struct iio_dev *indio_dev,
+				    struct iio_chan_spec const *chan,
+				    long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		return IIO_VAL_INT_PLUS_MICRO_DB;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ad8366_info = {
+	.read_raw = &ad8366_read_raw,
+	.write_raw = &ad8366_write_raw,
+	.write_raw_get_fmt = &ad8366_write_raw_get_fmt,
+};
+
+#define AD8366_CHAN(_channel) {				\
+	.type = IIO_VOLTAGE,				\
+	.output = 1,					\
+	.indexed = 1,					\
+	.channel = _channel,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),\
+}
+
+static const struct iio_chan_spec ad8366_channels[] = {
+	AD8366_CHAN(0),
+	AD8366_CHAN(1),
+};
+
+static int ad8366_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct gpio_desc *enable_gpio;
+	struct reset_control *rstc;
+	struct iio_dev *indio_dev;
+	struct ad8366_state *st;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	ret = devm_mutex_init(dev, &st->lock);
+	if (ret)
+		return ret;
+
+	ret = devm_regulator_get_enable(dev, "vcc");
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get regulator\n");
+
+	st->spi = spi;
+	st->info = spi_get_device_match_data(spi);
+
+	enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
+	if (IS_ERR(enable_gpio))
+		return dev_err_probe(dev, PTR_ERR(enable_gpio),
+				     "Failed to get enable GPIO\n");
+
+	rstc = devm_reset_control_get_optional_exclusive_deasserted(dev, NULL);
+	if (IS_ERR(rstc))
+		return dev_err_probe(dev, PTR_ERR(rstc),
+				     "Failed to get reset controller\n");
+
+	indio_dev->name = st->info->name;
+	indio_dev->info = &ad8366_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ad8366_channels;
+	indio_dev->num_channels = st->info->num_channels;
+
+	ret = ad8366_write_code(st);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to write initial gain\n");
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct spi_device_id ad8366_id[] = {
+	{ .name = "ad8366", .driver_data = (kernel_ulong_t)&ad8366_chip_info },
+	{ .name = "ada4961", .driver_data = (kernel_ulong_t)&ada4961_chip_info },
+	{ .name = "adl5240", .driver_data = (kernel_ulong_t)&adl5240_chip_info },
+	{ .name = "adrf5702", .driver_data = (kernel_ulong_t)&adrf5702_chip_info },
+	{ .name = "adrf5703", .driver_data = (kernel_ulong_t)&adrf5703_chip_info },
+	{ .name = "adrf5720", .driver_data = (kernel_ulong_t)&adrf5720_chip_info },
+	{ .name = "adrf5730", .driver_data = (kernel_ulong_t)&adrf5730_chip_info },
+	{ .name = "adrf5731", .driver_data = (kernel_ulong_t)&adrf5731_chip_info },
+	{ .name = "hmc271a", .driver_data = (kernel_ulong_t)&hmc271_chip_info },
+	{ .name = "hmc792a", .driver_data = (kernel_ulong_t)&hmc792_chip_info },
+	{ .name = "hmc1018a", .driver_data = (kernel_ulong_t)&hmc1018_chip_info },
+	{ .name = "hmc1019a", .driver_data = (kernel_ulong_t)&hmc1019_chip_info },
+	{ .name = "hmc1119", .driver_data = (kernel_ulong_t)&hmc1119_chip_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ad8366_id);
+
+static const struct of_device_id ad8366_of_match[] = {
+	{ .compatible = "adi,ad8366", .data = &ad8366_chip_info },
+	{ .compatible = "adi,ada4961", .data = &ada4961_chip_info },
+	{ .compatible = "adi,adl5240", .data = &adl5240_chip_info },
+	{ .compatible = "adi,adrf5702", .data = &adrf5702_chip_info },
+	{ .compatible = "adi,adrf5703", .data = &adrf5703_chip_info },
+	{ .compatible = "adi,adrf5720", .data = &adrf5720_chip_info },
+	{ .compatible = "adi,adrf5730", .data = &adrf5730_chip_info },
+	{ .compatible = "adi,adrf5731", .data = &adrf5731_chip_info },
+	{ .compatible = "adi,hmc271a", .data = &hmc271_chip_info },
+	{ .compatible = "adi,hmc792a", .data = &hmc792_chip_info },
+	{ .compatible = "adi,hmc1018a", .data = &hmc1018_chip_info },
+	{ .compatible = "adi,hmc1019a", .data = &hmc1019_chip_info },
+	{ .compatible = "adi,hmc1119", .data = &hmc1119_chip_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ad8366_of_match);
+
+static struct spi_driver ad8366_driver = {
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.of_match_table	= ad8366_of_match,
+	},
+	.probe		= ad8366_probe,
+	.id_table	= ad8366_id,
+};
+
+module_spi_driver(ad8366_driver);
+
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD8366 and similar Gain Amplifiers");
+MODULE_LICENSE("GPL v2");