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/keyboard/st-keyscan.c | 271 ++++++++++++++++++++++++++++++++++++ 1 file changed, 271 insertions(+) create mode 100644 drivers/input/keyboard/st-keyscan.c (limited to 'drivers/input/keyboard/st-keyscan.c') diff --git a/drivers/input/keyboard/st-keyscan.c b/drivers/input/keyboard/st-keyscan.c new file mode 100644 index 000000000..e53ef4c67 --- /dev/null +++ b/drivers/input/keyboard/st-keyscan.c @@ -0,0 +1,271 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * STMicroelectronics Key Scanning driver + * + * Copyright (c) 2014 STMicroelectonics Ltd. + * Author: Stuart Menefy + * + * Based on sh_keysc.c, copyright 2008 Magnus Damm + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define ST_KEYSCAN_MAXKEYS 16 + +#define KEYSCAN_CONFIG_OFF 0x0 +#define KEYSCAN_CONFIG_ENABLE 0x1 +#define KEYSCAN_DEBOUNCE_TIME_OFF 0x4 +#define KEYSCAN_MATRIX_STATE_OFF 0x8 +#define KEYSCAN_MATRIX_DIM_OFF 0xc +#define KEYSCAN_MATRIX_DIM_X_SHIFT 0x0 +#define KEYSCAN_MATRIX_DIM_Y_SHIFT 0x2 + +struct st_keyscan { + void __iomem *base; + int irq; + struct clk *clk; + struct input_dev *input_dev; + unsigned long last_state; + unsigned int n_rows; + unsigned int n_cols; + unsigned int debounce_us; +}; + +static irqreturn_t keyscan_isr(int irq, void *dev_id) +{ + struct st_keyscan *keypad = dev_id; + unsigned short *keycode = keypad->input_dev->keycode; + unsigned long state, change; + int bit_nr; + + state = readl(keypad->base + KEYSCAN_MATRIX_STATE_OFF) & 0xffff; + change = keypad->last_state ^ state; + keypad->last_state = state; + + for_each_set_bit(bit_nr, &change, BITS_PER_LONG) + input_report_key(keypad->input_dev, + keycode[bit_nr], state & BIT(bit_nr)); + + input_sync(keypad->input_dev); + + return IRQ_HANDLED; +} + +static int keyscan_start(struct st_keyscan *keypad) +{ + int error; + + error = clk_enable(keypad->clk); + if (error) + return error; + + writel(keypad->debounce_us * (clk_get_rate(keypad->clk) / 1000000), + keypad->base + KEYSCAN_DEBOUNCE_TIME_OFF); + + writel(((keypad->n_cols - 1) << KEYSCAN_MATRIX_DIM_X_SHIFT) | + ((keypad->n_rows - 1) << KEYSCAN_MATRIX_DIM_Y_SHIFT), + keypad->base + KEYSCAN_MATRIX_DIM_OFF); + + writel(KEYSCAN_CONFIG_ENABLE, keypad->base + KEYSCAN_CONFIG_OFF); + + return 0; +} + +static void keyscan_stop(struct st_keyscan *keypad) +{ + writel(0, keypad->base + KEYSCAN_CONFIG_OFF); + + clk_disable(keypad->clk); +} + +static int keyscan_open(struct input_dev *dev) +{ + struct st_keyscan *keypad = input_get_drvdata(dev); + + return keyscan_start(keypad); +} + +static void keyscan_close(struct input_dev *dev) +{ + struct st_keyscan *keypad = input_get_drvdata(dev); + + keyscan_stop(keypad); +} + +static int keypad_matrix_key_parse_dt(struct st_keyscan *keypad_data) +{ + struct device *dev = keypad_data->input_dev->dev.parent; + struct device_node *np = dev->of_node; + int error; + + error = matrix_keypad_parse_properties(dev, &keypad_data->n_rows, + &keypad_data->n_cols); + if (error) { + dev_err(dev, "failed to parse keypad params\n"); + return error; + } + + of_property_read_u32(np, "st,debounce-us", &keypad_data->debounce_us); + + dev_dbg(dev, "n_rows=%d n_col=%d debounce=%d\n", + keypad_data->n_rows, keypad_data->n_cols, + keypad_data->debounce_us); + + return 0; +} + +static int keyscan_probe(struct platform_device *pdev) +{ + struct st_keyscan *keypad_data; + struct input_dev *input_dev; + int error; + + if (!pdev->dev.of_node) { + dev_err(&pdev->dev, "no DT data present\n"); + return -EINVAL; + } + + keypad_data = devm_kzalloc(&pdev->dev, sizeof(*keypad_data), + GFP_KERNEL); + if (!keypad_data) + return -ENOMEM; + + input_dev = devm_input_allocate_device(&pdev->dev); + if (!input_dev) { + dev_err(&pdev->dev, "failed to allocate the input device\n"); + return -ENOMEM; + } + + input_dev->name = pdev->name; + input_dev->phys = "keyscan-keys/input0"; + input_dev->dev.parent = &pdev->dev; + input_dev->open = keyscan_open; + input_dev->close = keyscan_close; + + input_dev->id.bustype = BUS_HOST; + + keypad_data->input_dev = input_dev; + + error = keypad_matrix_key_parse_dt(keypad_data); + if (error) + return error; + + error = matrix_keypad_build_keymap(NULL, NULL, + keypad_data->n_rows, + keypad_data->n_cols, + NULL, input_dev); + if (error) { + dev_err(&pdev->dev, "failed to build keymap\n"); + return error; + } + + input_set_drvdata(input_dev, keypad_data); + + keypad_data->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); + if (IS_ERR(keypad_data->base)) + return PTR_ERR(keypad_data->base); + + keypad_data->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(keypad_data->clk)) { + dev_err(&pdev->dev, "cannot get clock\n"); + return PTR_ERR(keypad_data->clk); + } + + error = clk_enable(keypad_data->clk); + if (error) { + dev_err(&pdev->dev, "failed to enable clock\n"); + return error; + } + + keyscan_stop(keypad_data); + + keypad_data->irq = platform_get_irq(pdev, 0); + if (keypad_data->irq < 0) + return -EINVAL; + + error = devm_request_irq(&pdev->dev, keypad_data->irq, keyscan_isr, 0, + pdev->name, keypad_data); + if (error) { + dev_err(&pdev->dev, "failed to request IRQ\n"); + return error; + } + + error = input_register_device(input_dev); + if (error) { + dev_err(&pdev->dev, "failed to register input device\n"); + return error; + } + + platform_set_drvdata(pdev, keypad_data); + + device_set_wakeup_capable(&pdev->dev, 1); + + return 0; +} + +static int keyscan_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct st_keyscan *keypad = platform_get_drvdata(pdev); + struct input_dev *input = keypad->input_dev; + + guard(mutex)(&input->mutex); + + if (device_may_wakeup(dev)) + enable_irq_wake(keypad->irq); + else if (input_device_enabled(input)) + keyscan_stop(keypad); + + return 0; +} + +static int keyscan_resume(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct st_keyscan *keypad = platform_get_drvdata(pdev); + struct input_dev *input = keypad->input_dev; + int error; + + guard(mutex)(&input->mutex); + + if (device_may_wakeup(dev)) { + disable_irq_wake(keypad->irq); + } else if (input_device_enabled(input)) { + error = keyscan_start(keypad); + if (error) + return error; + } + + return 0; +} + +static DEFINE_SIMPLE_DEV_PM_OPS(keyscan_dev_pm_ops, + keyscan_suspend, keyscan_resume); + +static const struct of_device_id keyscan_of_match[] = { + { .compatible = "st,sti-keyscan" }, + { }, +}; +MODULE_DEVICE_TABLE(of, keyscan_of_match); + +static struct platform_driver keyscan_device_driver = { + .probe = keyscan_probe, + .driver = { + .name = "st-keyscan", + .pm = pm_sleep_ptr(&keyscan_dev_pm_ops), + .of_match_table = keyscan_of_match, + } +}; + +module_platform_driver(keyscan_device_driver); + +MODULE_AUTHOR("Stuart Menefy "); +MODULE_DESCRIPTION("STMicroelectronics keyscan device driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1