From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops 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 --- drivers/input/joystick/adc-joystick.c | 332 ++++++++++++++++++++++++++++++++++ 1 file changed, 332 insertions(+) create mode 100644 drivers/input/joystick/adc-joystick.c (limited to 'drivers/input/joystick/adc-joystick.c') diff --git a/drivers/input/joystick/adc-joystick.c b/drivers/input/joystick/adc-joystick.c new file mode 100644 index 000000000..4fa42f88b --- /dev/null +++ b/drivers/input/joystick/adc-joystick.c @@ -0,0 +1,332 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Input driver for joysticks connected over ADC. + * Copyright (c) 2019-2020 Artur Rojek + */ +#include +#include +#include +#include +#include +#include +#include + +#include + +struct adc_joystick_axis { + u32 code; + bool inverted; +}; + +struct adc_joystick { + struct input_dev *input; + struct iio_cb_buffer *buffer; + struct iio_channel *chans; + unsigned int num_chans; + struct adc_joystick_axis axes[] __counted_by(num_chans); +}; + +static int adc_joystick_invert(struct input_dev *dev, + unsigned int axis, int val) +{ + int min = input_abs_get_min(dev, axis); + int max = input_abs_get_max(dev, axis); + + return (max + min) - val; +} + +static void adc_joystick_poll(struct input_dev *input) +{ + struct adc_joystick *joy = input_get_drvdata(input); + int i, val, ret; + + for (i = 0; i < joy->num_chans; i++) { + ret = iio_read_channel_raw(&joy->chans[i], &val); + if (ret < 0) + return; + if (joy->axes[i].inverted) + val = adc_joystick_invert(input, i, val); + input_report_abs(input, joy->axes[i].code, val); + } + input_sync(input); +} + +static int adc_joystick_handle(const void *data, void *private) +{ + struct adc_joystick *joy = private; + enum iio_endian endianness; + int bytes, msb, val, idx, i; + const u16 *data_u16; + bool sign; + + bytes = joy->chans[0].channel->scan_type.storagebits >> 3; + + for (i = 0; i < joy->num_chans; ++i) { + idx = joy->chans[i].channel->scan_index; + endianness = joy->chans[i].channel->scan_type.endianness; + msb = joy->chans[i].channel->scan_type.realbits - 1; + sign = tolower(joy->chans[i].channel->scan_type.sign) == 's'; + + switch (bytes) { + case 1: + val = ((const u8 *)data)[idx]; + break; + case 2: + data_u16 = (const u16 *)data + idx; + + /* + * Data is aligned to the sample size by IIO core. + * Call `get_unaligned_xe16` to hide type casting. + */ + if (endianness == IIO_BE) + val = get_unaligned_be16(data_u16); + else if (endianness == IIO_LE) + val = get_unaligned_le16(data_u16); + else /* IIO_CPU */ + val = *data_u16; + break; + default: + return -EINVAL; + } + + val >>= joy->chans[i].channel->scan_type.shift; + if (sign) + val = sign_extend32(val, msb); + else + val &= GENMASK(msb, 0); + if (joy->axes[i].inverted) + val = adc_joystick_invert(joy->input, i, val); + input_report_abs(joy->input, joy->axes[i].code, val); + } + + input_sync(joy->input); + + return 0; +} + +static int adc_joystick_open(struct input_dev *dev) +{ + struct adc_joystick *joy = input_get_drvdata(dev); + struct device *devp = &dev->dev; + int ret; + + ret = iio_channel_start_all_cb(joy->buffer); + if (ret) + dev_err(devp, "Unable to start callback buffer: %d\n", ret); + + return ret; +} + +static void adc_joystick_close(struct input_dev *dev) +{ + struct adc_joystick *joy = input_get_drvdata(dev); + + iio_channel_stop_all_cb(joy->buffer); +} + +static void adc_joystick_cleanup(void *data) +{ + iio_channel_release_all_cb(data); +} + +static int adc_joystick_set_axes(struct device *dev, struct adc_joystick *joy) +{ + struct adc_joystick_axis *axes = joy->axes; + s32 range[2], fuzz, flat; + unsigned int num_axes; + int error, i; + + num_axes = device_get_child_node_count(dev); + if (!num_axes) { + dev_err(dev, "Unable to find child nodes\n"); + return -EINVAL; + } + + if (num_axes != joy->num_chans) { + dev_err(dev, "Got %d child nodes for %d channels\n", + num_axes, joy->num_chans); + return -EINVAL; + } + + device_for_each_child_node_scoped(dev, child) { + error = fwnode_property_read_u32(child, "reg", &i); + if (error) { + dev_err(dev, "reg invalid or missing\n"); + return error; + } + + if (i >= num_axes) { + dev_err(dev, "No matching axis for reg %d\n", i); + return -EINVAL; + } + + error = fwnode_property_read_u32(child, "linux,code", + &axes[i].code); + if (error) { + dev_err(dev, "linux,code invalid or missing\n"); + return error; + } + + error = fwnode_property_read_u32_array(child, "abs-range", + range, 2); + if (error) { + dev_err(dev, "abs-range invalid or missing\n"); + return error; + } + + if (range[0] > range[1]) { + dev_dbg(dev, "abs-axis %d inverted\n", i); + axes[i].inverted = true; + swap(range[0], range[1]); + } + + if (fwnode_property_read_u32(child, "abs-fuzz", &fuzz)) + fuzz = 0; + + if (fwnode_property_read_u32(child, "abs-flat", &flat)) + flat = 0; + + input_set_abs_params(joy->input, axes[i].code, + range[0], range[1], fuzz, flat); + } + + return 0; +} + + +static int adc_joystick_count_channels(struct device *dev, + const struct iio_channel *chans, + bool polled, + unsigned int *num_chans) +{ + int bits; + int i; + + /* + * Count how many channels we got. NULL terminated. + * Do not check the storage size if using polling. + */ + for (i = 0; chans[i].indio_dev; i++) { + if (polled) + continue; + bits = chans[i].channel->scan_type.storagebits; + if (!bits || bits > 16) { + dev_err(dev, "Unsupported channel storage size\n"); + return -EINVAL; + } + if (bits != chans[0].channel->scan_type.storagebits) { + dev_err(dev, "Channels must have equal storage size\n"); + return -EINVAL; + } + } + + *num_chans = i; + return 0; +} + +static int adc_joystick_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct iio_channel *chans; + struct adc_joystick *joy; + struct input_dev *input; + unsigned int poll_interval = 0; + unsigned int num_chans; + int error; + + chans = devm_iio_channel_get_all(dev); + error = PTR_ERR_OR_ZERO(chans); + if (error) { + if (error != -EPROBE_DEFER) + dev_err(dev, "Unable to get IIO channels"); + return error; + } + + error = device_property_read_u32(dev, "poll-interval", &poll_interval); + if (error) { + /* -EINVAL means the property is absent. */ + if (error != -EINVAL) + return error; + } else if (poll_interval == 0) { + dev_err(dev, "Unable to get poll-interval\n"); + return -EINVAL; + } + + error = adc_joystick_count_channels(dev, chans, poll_interval != 0, + &num_chans); + if (error) + return error; + + joy = devm_kzalloc(dev, struct_size(joy, axes, num_chans), GFP_KERNEL); + if (!joy) + return -ENOMEM; + + joy->chans = chans; + joy->num_chans = num_chans; + + input = devm_input_allocate_device(dev); + if (!input) { + dev_err(dev, "Unable to allocate input device\n"); + return -ENOMEM; + } + + joy->input = input; + input->name = pdev->name; + input->id.bustype = BUS_HOST; + + error = adc_joystick_set_axes(dev, joy); + if (error) + return error; + + if (poll_interval != 0) { + input_setup_polling(input, adc_joystick_poll); + input_set_poll_interval(input, poll_interval); + } else { + input->open = adc_joystick_open; + input->close = adc_joystick_close; + + joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, + joy); + if (IS_ERR(joy->buffer)) { + dev_err(dev, "Unable to allocate callback buffer\n"); + return PTR_ERR(joy->buffer); + } + + error = devm_add_action_or_reset(dev, adc_joystick_cleanup, + joy->buffer); + if (error) { + dev_err(dev, "Unable to add action\n"); + return error; + } + } + + input_set_drvdata(input, joy); + + error = input_register_device(input); + if (error) { + dev_err(dev, "Unable to register input device\n"); + return error; + } + + return 0; +} + +static const struct of_device_id adc_joystick_of_match[] = { + { .compatible = "adc-joystick", }, + { } +}; +MODULE_DEVICE_TABLE(of, adc_joystick_of_match); + +static struct platform_driver adc_joystick_driver = { + .driver = { + .name = "adc-joystick", + .of_match_table = adc_joystick_of_match, + }, + .probe = adc_joystick_probe, +}; +module_platform_driver(adc_joystick_driver); + +MODULE_DESCRIPTION("Input driver for joysticks connected over ADC"); +MODULE_AUTHOR("Artur Rojek "); +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS("IIO_CONSUMER"); -- cgit v1.3.1