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/misc/ariel-pwrbutton.c | 169 +++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 drivers/input/misc/ariel-pwrbutton.c (limited to 'drivers/input/misc/ariel-pwrbutton.c') diff --git a/drivers/input/misc/ariel-pwrbutton.c b/drivers/input/misc/ariel-pwrbutton.c new file mode 100644 index 000000000..f0e06ee60 --- /dev/null +++ b/drivers/input/misc/ariel-pwrbutton.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later +/* + * Dell Wyse 3020 a.k.a. "Ariel" Power Button Driver + * + * Copyright (C) 2020 Lubomir Rintel + */ + +#include +#include +#include +#include +#include +#include + +#define RESP_COUNTER(response) (response.header & 0x3) +#define RESP_SIZE(response) ((response.header >> 2) & 0x3) +#define RESP_TYPE(response) ((response.header >> 4) & 0xf) + +struct ec_input_response { + u8 reserved; + u8 header; + u8 data[3]; +} __packed; + +struct ariel_pwrbutton { + struct spi_device *client; + struct input_dev *input; + u8 msg_counter; +}; + +static int ec_input_read(struct ariel_pwrbutton *priv, + struct ec_input_response *response) +{ + u8 read_request[] = { 0x00, 0x5a, 0xa5, 0x00, 0x00 }; + struct spi_device *spi = priv->client; + struct spi_transfer t = { + .tx_buf = read_request, + .rx_buf = response, + .len = sizeof(read_request), + }; + + compiletime_assert(sizeof(read_request) == sizeof(*response), + "SPI xfer request/response size mismatch"); + + return spi_sync_transfer(spi, &t, 1); +} + +static irqreturn_t ec_input_interrupt(int irq, void *dev_id) +{ + struct ariel_pwrbutton *priv = dev_id; + struct spi_device *spi = priv->client; + struct ec_input_response response; + int error; + int i; + + error = ec_input_read(priv, &response); + if (error < 0) { + dev_err(&spi->dev, "EC read failed: %d\n", error); + goto out; + } + + if (priv->msg_counter == RESP_COUNTER(response)) { + dev_warn(&spi->dev, "No new data to read?\n"); + goto out; + } + + priv->msg_counter = RESP_COUNTER(response); + + if (RESP_TYPE(response) != 0x3 && RESP_TYPE(response) != 0xc) { + dev_dbg(&spi->dev, "Ignoring message that's not kbd data\n"); + goto out; + } + + for (i = 0; i < RESP_SIZE(response); i++) { + switch (response.data[i]) { + case 0x74: + input_report_key(priv->input, KEY_POWER, 1); + input_sync(priv->input); + break; + case 0xf4: + input_report_key(priv->input, KEY_POWER, 0); + input_sync(priv->input); + break; + default: + dev_dbg(&spi->dev, "Unknown scan code: %02x\n", + response.data[i]); + } + } + +out: + return IRQ_HANDLED; +} + +static int ariel_pwrbutton_probe(struct spi_device *spi) +{ + struct ec_input_response response; + struct ariel_pwrbutton *priv; + int error; + + if (!spi->irq) { + dev_err(&spi->dev, "Missing IRQ.\n"); + return -EINVAL; + } + + priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->client = spi; + spi_set_drvdata(spi, priv); + + priv->input = devm_input_allocate_device(&spi->dev); + if (!priv->input) + return -ENOMEM; + priv->input->name = "Power Button"; + priv->input->dev.parent = &spi->dev; + input_set_capability(priv->input, EV_KEY, KEY_POWER); + error = input_register_device(priv->input); + if (error) { + dev_err(&spi->dev, "error registering input device: %d\n", error); + return error; + } + + error = ec_input_read(priv, &response); + if (error < 0) { + dev_err(&spi->dev, "EC read failed: %d\n", error); + return error; + } + priv->msg_counter = RESP_COUNTER(response); + + error = devm_request_threaded_irq(&spi->dev, spi->irq, NULL, + ec_input_interrupt, + IRQF_ONESHOT, + "Ariel EC Input", priv); + + if (error) { + dev_err(&spi->dev, "Failed to request IRQ %d: %d\n", + spi->irq, error); + return error; + } + + return 0; +} + +static const struct of_device_id ariel_pwrbutton_of_match[] = { + { .compatible = "dell,wyse-ariel-ec-input" }, + { } +}; +MODULE_DEVICE_TABLE(of, ariel_pwrbutton_of_match); + +static const struct spi_device_id ariel_pwrbutton_spi_ids[] = { + { .name = "wyse-ariel-ec-input" }, + { } +}; +MODULE_DEVICE_TABLE(spi, ariel_pwrbutton_spi_ids); + +static struct spi_driver ariel_pwrbutton_driver = { + .driver = { + .name = "dell-wyse-ariel-ec-input", + .of_match_table = ariel_pwrbutton_of_match, + }, + .probe = ariel_pwrbutton_probe, + .id_table = ariel_pwrbutton_spi_ids, +}; +module_spi_driver(ariel_pwrbutton_driver); + +MODULE_AUTHOR("Lubomir Rintel "); +MODULE_DESCRIPTION("Dell Wyse 3020 Power Button Input Driver"); +MODULE_LICENSE("Dual BSD/GPL"); -- cgit v1.3.1