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, 370 insertions, 0 deletions

diff --git a/drivers/input/keyboard/adp5585-keys.c b/drivers/input/keyboard/adp5585-keys.c
new file mode 100644
index 000000000..017c95029
--- /dev/null
+++ b/drivers/input/keyboard/adp5585-keys.c
@@ -0,0 +1,370 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices ADP5585 Keys driver
+ *
+ * Copyright (C) 2025 Analog Devices, Inc.
+ */
+
+#include <linux/bitmap.h>
+#include <linux/container_of.h>
+#include <linux/device.h>
+#include <linux/find.h>
+#include <linux/input.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/mfd/adp5585.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+/* As needed for the matrix parsing code */
+#define ADP5589_MAX_KEYMAPSIZE		123
+
+struct adp5585_kpad_chip {
+	u8 key_ev_min;
+	u8 key_ev_max;
+	u8 max_rows;
+	u8 max_cols;
+};
+
+struct adp5585_kpad {
+	const struct adp5585_kpad_chip *info;
+	struct notifier_block nb;
+	struct input_dev *input;
+	unsigned short keycode[ADP5589_MAX_KEYMAPSIZE];
+	struct device *dev;
+	unsigned long keypad;
+	int row_shift;
+};
+
+static int adp5585_keys_validate_events(const struct adp5585_kpad *kpad,
+					const u32 *events, u32 n_events)
+{
+	unsigned int ev;
+	u32 row, col;
+
+	for (ev = 0; ev < n_events; ev++) {
+		if (events[ev] < kpad->info->key_ev_min ||
+		    events[ev] > kpad->info->key_ev_max)
+			continue;
+
+		/*
+		 * if the event is to be generated by the keymap, we need to make
+		 * sure that the pins are part of it!
+		 */
+		row = (events[ev] - 1) / kpad->info->max_cols;
+		col = (events[ev] - 1) % kpad->info->max_cols;
+
+		if (test_bit(row, &kpad->keypad) &&
+		    test_bit(col + kpad->info->max_rows, &kpad->keypad))
+			continue;
+
+		return dev_err_probe(kpad->dev, -EINVAL,
+				     "Invalid unlock/reset event(%u) not used in the keypad\n",
+				     events[ev]);
+	}
+
+	return 0;
+}
+
+static int adp5585_keys_check_special_events(const struct adp5585_dev *adp5585,
+					     const struct adp5585_kpad *kpad)
+{
+	int error;
+
+	error = adp5585_keys_validate_events(kpad, adp5585->unlock_keys,
+					     adp5585->nkeys_unlock);
+	if (error)
+		return error;
+
+	error = adp5585_keys_validate_events(kpad, adp5585->reset1_keys,
+					     adp5585->nkeys_reset1);
+	if (error)
+		return error;
+
+	return adp5585_keys_validate_events(kpad, adp5585->reset2_keys,
+					    adp5585->nkeys_reset2);
+}
+
+static void adp5585_keys_pins_free(void *data)
+{
+	struct adp5585_kpad *kpad = data;
+	struct adp5585_dev *adp5585 = dev_get_drvdata(kpad->dev->parent);
+	unsigned int pin;
+
+	for_each_set_bit(pin, &kpad->keypad, adp5585->n_pins)
+		clear_bit(pin, adp5585->pin_usage);
+}
+
+static int adp5585_keys_parse_fw(const struct adp5585_dev *adp5585,
+				 struct adp5585_kpad *kpad)
+{
+	struct device *dev = kpad->dev;
+	u32 cols = 0, rows = 0, pin;
+	int error, n_pins;
+
+	/*
+	 * We do not check for errors (or no value) since the input device is
+	 * only added if this property is present in the first place.
+	 */
+	n_pins = device_property_count_u32(dev, "adi,keypad-pins");
+	if (n_pins > adp5585->n_pins)
+		return dev_err_probe(dev, -EINVAL,
+				     "Too many keypad pins (%d) defined (max=%d)\n",
+				     n_pins, adp5585->n_pins);
+
+	unsigned int *keypad_pins __free(kfree) = kcalloc(n_pins, sizeof(*keypad_pins),
+							  GFP_KERNEL);
+	if (!keypad_pins)
+		return -ENOMEM;
+
+	error = device_property_read_u32_array(dev, "adi,keypad-pins",
+					       keypad_pins, n_pins);
+	if (error)
+		return error;
+
+	/*
+	 * We can add the action here since it makes the code easier and nothing
+	 * "bad" will happen out of it. Worst case, it will be a no-op and no
+	 * bit will set.
+	 */
+	error = devm_add_action_or_reset(dev, adp5585_keys_pins_free, kpad);
+	if (error)
+		return error;
+
+	for (pin = 0; pin < n_pins; pin++) {
+		if (keypad_pins[pin] >= adp5585->n_pins)
+			return dev_err_probe(dev, -EINVAL,
+					     "Invalid keypad pin(%u) defined\n",
+					     keypad_pins[pin]);
+
+		if (test_and_set_bit(keypad_pins[pin], adp5585->pin_usage))
+			return dev_err_probe(dev, -EBUSY,
+					     "Keypad pin(%u) already used\n",
+					     keypad_pins[pin]);
+
+		__set_bit(keypad_pins[pin], &kpad->keypad);
+	}
+
+	/*
+	 * Note that given that we get a mask (and the HW allows it), we
+	 * can have holes in our keypad (eg: row0, row1 and row7 enabled).
+	 * However, for the matrix parsing functions we need to pass the
+	 * number of rows/cols as the maximum row/col used plus 1. This
+	 * pretty much means we will also have holes in our SW keypad.
+	 */
+
+	rows = find_last_bit(&kpad->keypad, kpad->info->max_rows) + 1;
+	if (rows == kpad->info->max_rows + 1)
+		return dev_err_probe(dev, -EINVAL,
+				     "Now rows defined in the keypad!\n");
+
+	cols = find_last_bit(&kpad->keypad, kpad->info->max_cols + kpad->info->max_rows);
+	if (cols < kpad->info->max_rows)
+		return dev_err_probe(dev, -EINVAL,
+				     "No columns defined in the keypad!\n");
+
+	cols = cols + 1 - kpad->info->max_rows;
+
+	error = matrix_keypad_build_keymap(NULL, NULL, rows, cols,
+					   kpad->keycode, kpad->input);
+	if (error)
+		return error;
+
+	kpad->row_shift = get_count_order(cols);
+
+	if (device_property_read_bool(kpad->dev, "autorepeat"))
+		__set_bit(EV_REP, kpad->input->evbit);
+
+	error = adp5585_keys_check_special_events(adp5585, kpad);
+	if (error)
+		return error;
+
+	return 0;
+}
+
+static int adp5585_keys_setup(const struct adp5585_dev *adp5585,
+			      struct adp5585_kpad *kpad)
+{
+	unsigned long keys_bits, start = 0, nbits = kpad->info->max_rows;
+	const struct adp5585_regs *regs = adp5585->regs;
+	unsigned int i = 0, max_cols = kpad->info->max_cols;
+	int error;
+
+	/*
+	 * Take care as the below assumes max_rows is always less or equal than
+	 * 8 which is true for the supported devices. If we happen to add
+	 * another device we need to make sure this still holds true. Although
+	 * adding a new device is very unlikely.
+	 */
+	do {
+		keys_bits = bitmap_read(&kpad->keypad, start, nbits);
+		if (keys_bits) {
+			error = regmap_write(adp5585->regmap, regs->pin_cfg_a + i,
+					     keys_bits);
+			if (error)
+				return error;
+		}
+
+		start += nbits;
+		if (max_cols > 8) {
+			nbits = 8;
+			max_cols -= nbits;
+		} else {
+			nbits = max_cols;
+		}
+
+		i++;
+	} while (start < kpad->info->max_rows + kpad->info->max_cols);
+
+	return 0;
+}
+
+static int adp5585_keys_ev_handle(struct notifier_block *nb, unsigned long key,
+				  void *data)
+{
+	struct adp5585_kpad *kpad = container_of(nb, struct adp5585_kpad, nb);
+	unsigned long key_press = (unsigned long)data;
+	unsigned int row, col, code;
+
+	/* make sure the event is for us */
+	if (key < kpad->info->key_ev_min || key > kpad->info->key_ev_max)
+		return NOTIFY_DONE;
+
+	/*
+	 * Unlikely but lets be on the safe side! We do not return any error
+	 * because the event was indeed for us but with some weird value. So,
+	 * we still want the caller know that the right handler was called.
+	 */
+	if (!key)
+		return NOTIFY_BAD;
+
+	row = (key - 1) / (kpad->info->max_cols);
+	col = (key - 1) % (kpad->info->max_cols);
+	code = MATRIX_SCAN_CODE(row, col, kpad->row_shift);
+
+	dev_dbg_ratelimited(kpad->dev, "report key(%lu) r(%d) c(%d) code(%d)\n",
+			    key, row, col, kpad->keycode[code]);
+
+	input_report_key(kpad->input, kpad->keycode[code], key_press);
+	input_sync(kpad->input);
+
+	return NOTIFY_STOP;
+}
+
+static void adp5585_keys_unreg_notifier(void *data)
+{
+	struct adp5585_kpad *kpad = data;
+	struct adp5585_dev *adp5585 = dev_get_drvdata(kpad->dev->parent);
+
+	blocking_notifier_chain_unregister(&adp5585->event_notifier,
+					   &kpad->nb);
+}
+
+static int adp5585_keys_probe(struct platform_device *pdev)
+{
+	const struct platform_device_id *id = platform_get_device_id(pdev);
+	struct adp5585_dev *adp5585 = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct adp5585_kpad *kpad;
+	unsigned int revid;
+	const char *phys;
+	int error;
+
+	kpad = devm_kzalloc(dev, sizeof(*kpad), GFP_KERNEL);
+	if (!kpad)
+		return -ENOMEM;
+
+	if (!adp5585->irq)
+		return dev_err_probe(dev, -EINVAL,
+				     "IRQ is mandatory for the keypad\n");
+
+	kpad->dev = dev;
+
+	kpad->input = devm_input_allocate_device(dev);
+	if (!kpad->input)
+		return -ENOMEM;
+
+	kpad->info = (const struct adp5585_kpad_chip *)id->driver_data;
+	if (!kpad->info)
+		return -ENODEV;
+
+	error = regmap_read(adp5585->regmap, ADP5585_ID, &revid);
+	if (error)
+		return dev_err_probe(dev, error, "Failed to read device ID\n");
+
+	phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input0", pdev->name);
+	if (!phys)
+		return -ENOMEM;
+
+	kpad->input->name = pdev->name;
+	kpad->input->phys = phys;
+
+	kpad->input->id.bustype = BUS_I2C;
+	kpad->input->id.vendor = 0x0001;
+	kpad->input->id.product = 0x0001;
+	kpad->input->id.version = revid & ADP5585_REV_ID_MASK;
+
+	device_set_of_node_from_dev(dev, dev->parent);
+
+	error = adp5585_keys_parse_fw(adp5585, kpad);
+	if (error)
+		return error;
+
+	error = adp5585_keys_setup(adp5585, kpad);
+	if (error)
+		return error;
+
+	kpad->nb.notifier_call = adp5585_keys_ev_handle;
+	error = blocking_notifier_chain_register(&adp5585->event_notifier,
+						 &kpad->nb);
+	if (error)
+		return error;
+
+	error = devm_add_action_or_reset(dev, adp5585_keys_unreg_notifier, kpad);
+	if (error)
+		return error;
+
+	error = input_register_device(kpad->input);
+	if (error)
+		return dev_err_probe(dev, error,
+				     "Failed to register input device\n");
+
+	return 0;
+}
+
+static const struct adp5585_kpad_chip adp5585_kpad_chip_info = {
+	.max_rows = 6,
+	.max_cols = 5,
+	.key_ev_min = ADP5585_ROW5_KEY_EVENT_START,
+	.key_ev_max = ADP5585_ROW5_KEY_EVENT_END,
+};
+
+static const struct adp5585_kpad_chip adp5589_kpad_chip_info = {
+	.max_rows = 8,
+	.max_cols = 11,
+	.key_ev_min = ADP5589_KEY_EVENT_START,
+	.key_ev_max = ADP5589_KEY_EVENT_END,
+};
+
+static const struct platform_device_id adp5585_keys_id_table[] = {
+	{ "adp5585-keys", (kernel_ulong_t)&adp5585_kpad_chip_info },
+	{ "adp5589-keys", (kernel_ulong_t)&adp5589_kpad_chip_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, adp5585_keys_id_table);
+
+static struct platform_driver adp5585_keys_driver = {
+	.driver	= {
+		.name = "adp5585-keys",
+	},
+	.probe = adp5585_keys_probe,
+	.id_table = adp5585_keys_id_table,
+};
+module_platform_driver(adp5585_keys_driver);
+
+MODULE_AUTHOR("Nuno Sá <nuno.sa@analog.com>");
+MODULE_DESCRIPTION("ADP5585 Keys Driver");
+MODULE_LICENSE("GPL");