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, 496 insertions, 0 deletions

diff --git a/drivers/input/keyboard/omap4-keypad.c b/drivers/input/keyboard/omap4-keypad.c
new file mode 100644
index 000000000..e783244d0
--- /dev/null
+++ b/drivers/input/keyboard/omap4-keypad.c
@@ -0,0 +1,496 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * OMAP4 Keypad Driver
+ *
+ * Copyright (C) 2010 Texas Instruments
+ *
+ * Author: Abraham Arce <x0066660@ti.com>
+ * Initial Code: Syed Rafiuddin <rafiuddin.syed@ti.com>
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/input.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/slab.h>
+#include <linux/pm_runtime.h>
+#include <linux/pm_wakeirq.h>
+
+/* OMAP4 registers */
+#define OMAP4_KBD_REVISION		0x00
+#define OMAP4_KBD_SYSCONFIG		0x10
+#define OMAP4_KBD_SYSSTATUS		0x14
+#define OMAP4_KBD_IRQSTATUS		0x18
+#define OMAP4_KBD_IRQENABLE		0x1C
+#define OMAP4_KBD_WAKEUPENABLE		0x20
+#define OMAP4_KBD_PENDING		0x24
+#define OMAP4_KBD_CTRL			0x28
+#define OMAP4_KBD_DEBOUNCINGTIME	0x2C
+#define OMAP4_KBD_LONGKEYTIME		0x30
+#define OMAP4_KBD_TIMEOUT		0x34
+#define OMAP4_KBD_STATEMACHINE		0x38
+#define OMAP4_KBD_ROWINPUTS		0x3C
+#define OMAP4_KBD_COLUMNOUTPUTS		0x40
+#define OMAP4_KBD_FULLCODE31_0		0x44
+#define OMAP4_KBD_FULLCODE63_32		0x48
+
+/* OMAP4 bit definitions */
+#define OMAP4_DEF_IRQENABLE_EVENTEN	BIT(0)
+#define OMAP4_DEF_IRQENABLE_LONGKEY	BIT(1)
+#define OMAP4_DEF_WUP_EVENT_ENA		BIT(0)
+#define OMAP4_DEF_WUP_LONG_KEY_ENA	BIT(1)
+#define OMAP4_DEF_CTRL_NOSOFTMODE	BIT(1)
+#define OMAP4_DEF_CTRL_PTV_SHIFT	2
+
+/* OMAP4 values */
+#define OMAP4_VAL_IRQDISABLE		0x0
+
+/*
+ * Errata i689: If a key is released for a time shorter than debounce time,
+ * the keyboard will idle and never detect the key release. The workaround
+ * is to use at least a 12ms debounce time. See omap5432 TRM chapter
+ * "26.4.6.2 Keyboard Controller Timer" for more information.
+ */
+#define OMAP4_KEYPAD_PTV_DIV_128        0x6
+#define OMAP4_KEYPAD_DEBOUNCINGTIME_MS(dbms, ptv)     \
+	((((dbms) * 1000) / ((1 << ((ptv) + 1)) * (1000000 / 32768))) - 1)
+#define OMAP4_VAL_DEBOUNCINGTIME_16MS					\
+	OMAP4_KEYPAD_DEBOUNCINGTIME_MS(16, OMAP4_KEYPAD_PTV_DIV_128)
+#define OMAP4_KEYPAD_AUTOIDLE_MS	50	/* Approximate measured time */
+#define OMAP4_KEYPAD_IDLE_CHECK_MS	(OMAP4_KEYPAD_AUTOIDLE_MS / 2)
+
+enum {
+	KBD_REVISION_OMAP4 = 0,
+	KBD_REVISION_OMAP5,
+};
+
+struct omap4_keypad {
+	struct input_dev *input;
+
+	void __iomem *base;
+	unsigned int irq;
+	struct mutex lock;		/* for key scan */
+
+	unsigned int rows;
+	unsigned int cols;
+	u32 reg_offset;
+	u32 irqreg_offset;
+	unsigned int row_shift;
+	bool no_autorepeat;
+	u64 keys;
+	unsigned short *keymap;
+	struct clk *fck;
+};
+
+static int kbd_readl(struct omap4_keypad *keypad_data, u32 offset)
+{
+	return __raw_readl(keypad_data->base +
+				keypad_data->reg_offset + offset);
+}
+
+static void kbd_writel(struct omap4_keypad *keypad_data, u32 offset, u32 value)
+{
+	__raw_writel(value,
+		     keypad_data->base + keypad_data->reg_offset + offset);
+}
+
+static int kbd_read_irqreg(struct omap4_keypad *keypad_data, u32 offset)
+{
+	return __raw_readl(keypad_data->base +
+				keypad_data->irqreg_offset + offset);
+}
+
+static void kbd_write_irqreg(struct omap4_keypad *keypad_data,
+			     u32 offset, u32 value)
+{
+	__raw_writel(value,
+		     keypad_data->base + keypad_data->irqreg_offset + offset);
+}
+
+static int omap4_keypad_report_keys(struct omap4_keypad *keypad_data,
+				    u64 keys, bool down)
+{
+	struct input_dev *input_dev = keypad_data->input;
+	unsigned int col, row, code;
+	DECLARE_BITMAP(mask, 64);
+	unsigned long bit;
+	int events = 0;
+
+	bitmap_from_u64(mask, keys);
+
+	for_each_set_bit(bit, mask, keypad_data->rows * BITS_PER_BYTE) {
+		row = bit / BITS_PER_BYTE;
+		col = bit % BITS_PER_BYTE;
+		code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);
+
+		input_event(input_dev, EV_MSC, MSC_SCAN, code);
+		input_report_key(input_dev, keypad_data->keymap[code], down);
+
+		events++;
+	}
+
+	if (events)
+		input_sync(input_dev);
+
+	return events;
+}
+
+static void omap4_keypad_scan_keys(struct omap4_keypad *keypad_data, u64 keys)
+{
+	u64 changed;
+
+	guard(mutex)(&keypad_data->lock);
+
+	changed = keys ^ keypad_data->keys;
+
+	/*
+	 * Report key up events separately and first. This matters in case we
+	 * lost key-up interrupt and just now catching up.
+	 */
+	omap4_keypad_report_keys(keypad_data, changed & ~keys, false);
+
+	/* Report key down events */
+	omap4_keypad_report_keys(keypad_data, changed & keys, true);
+
+	keypad_data->keys = keys;
+}
+
+/* Interrupt handlers */
+static irqreturn_t omap4_keypad_irq_handler(int irq, void *dev_id)
+{
+	struct omap4_keypad *keypad_data = dev_id;
+
+	if (kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS))
+		return IRQ_WAKE_THREAD;
+
+	return IRQ_NONE;
+}
+
+static irqreturn_t omap4_keypad_irq_thread_fn(int irq, void *dev_id)
+{
+	struct omap4_keypad *keypad_data = dev_id;
+	struct device *dev = keypad_data->input->dev.parent;
+	u32 low, high;
+	int error;
+	u64 keys;
+
+	error = pm_runtime_resume_and_get(dev);
+	if (error)
+		return IRQ_NONE;
+
+	low = kbd_readl(keypad_data, OMAP4_KBD_FULLCODE31_0);
+	high = kbd_readl(keypad_data, OMAP4_KBD_FULLCODE63_32);
+	keys = low | (u64)high << 32;
+
+	omap4_keypad_scan_keys(keypad_data, keys);
+
+	/* clear pending interrupts */
+	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
+			 kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));
+
+	pm_runtime_put_autosuspend(dev);
+
+	return IRQ_HANDLED;
+}
+
+static int omap4_keypad_open(struct input_dev *input)
+{
+	struct omap4_keypad *keypad_data = input_get_drvdata(input);
+	struct device *dev = input->dev.parent;
+	int error;
+
+	error = pm_runtime_resume_and_get(dev);
+	if (error)
+		return error;
+
+	error = clk_prepare_enable(keypad_data->fck);
+	if (error)
+		goto out;
+
+	disable_irq(keypad_data->irq);
+
+	kbd_writel(keypad_data, OMAP4_KBD_CTRL,
+			OMAP4_DEF_CTRL_NOSOFTMODE |
+			(OMAP4_KEYPAD_PTV_DIV_128 << OMAP4_DEF_CTRL_PTV_SHIFT));
+	kbd_writel(keypad_data, OMAP4_KBD_DEBOUNCINGTIME,
+			OMAP4_VAL_DEBOUNCINGTIME_16MS);
+	/* clear pending interrupts */
+	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
+			 kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));
+	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
+			OMAP4_DEF_IRQENABLE_EVENTEN);
+	kbd_writel(keypad_data, OMAP4_KBD_WAKEUPENABLE,
+			OMAP4_DEF_WUP_EVENT_ENA);
+
+	enable_irq(keypad_data->irq);
+
+out:
+	pm_runtime_put_autosuspend(dev);
+
+	return error;
+}
+
+static void omap4_keypad_stop(struct omap4_keypad *keypad_data)
+{
+	/* Disable interrupts and wake-up events */
+	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
+			 OMAP4_VAL_IRQDISABLE);
+	kbd_writel(keypad_data, OMAP4_KBD_WAKEUPENABLE, 0);
+
+	/* clear pending interrupts */
+	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
+			 kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));
+}
+
+static void omap4_keypad_close(struct input_dev *input)
+{
+	struct omap4_keypad *keypad_data = input_get_drvdata(input);
+	struct device *dev = input->dev.parent;
+	int error;
+
+	error = pm_runtime_resume_and_get(dev);
+	if (error)
+		dev_err(dev, "%s: pm_runtime_resume_and_get() failed: %d\n",
+			__func__, error);
+
+	disable_irq(keypad_data->irq);
+	omap4_keypad_stop(keypad_data);
+	enable_irq(keypad_data->irq);
+	clk_disable_unprepare(keypad_data->fck);
+
+	pm_runtime_put_autosuspend(dev);
+}
+
+static int omap4_keypad_parse_dt(struct device *dev,
+				 struct omap4_keypad *keypad_data)
+{
+	struct device_node *np = dev->of_node;
+	int err;
+
+	err = matrix_keypad_parse_properties(dev, &keypad_data->rows,
+					     &keypad_data->cols);
+	if (err)
+		return err;
+
+	keypad_data->no_autorepeat = of_property_read_bool(np, "linux,input-no-autorepeat");
+
+	return 0;
+}
+
+static int omap4_keypad_check_revision(struct device *dev,
+				       struct omap4_keypad *keypad_data)
+{
+	unsigned int rev;
+
+	rev = __raw_readl(keypad_data->base + OMAP4_KBD_REVISION);
+	rev &= 0x03 << 30;
+	rev >>= 30;
+	switch (rev) {
+	case KBD_REVISION_OMAP4:
+		keypad_data->reg_offset = 0x00;
+		keypad_data->irqreg_offset = 0x00;
+		break;
+	case KBD_REVISION_OMAP5:
+		keypad_data->reg_offset = 0x10;
+		keypad_data->irqreg_offset = 0x0c;
+		break;
+	default:
+		dev_err(dev, "Keypad reports unsupported revision %d", rev);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Errata ID i689 "1.32 Keyboard Key Up Event Can Be Missed".
+ * Interrupt may not happen for key-up events. We must clear stuck
+ * key-up events after the keyboard hardware has auto-idled.
+ */
+static int omap4_keypad_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct omap4_keypad *keypad_data = platform_get_drvdata(pdev);
+	u32 active;
+
+	active = kbd_readl(keypad_data, OMAP4_KBD_STATEMACHINE);
+	if (active) {
+		pm_runtime_mark_last_busy(dev);
+		return -EBUSY;
+	}
+
+	omap4_keypad_scan_keys(keypad_data, 0);
+
+	return 0;
+}
+
+static const struct dev_pm_ops omap4_keypad_pm_ops = {
+	RUNTIME_PM_OPS(omap4_keypad_runtime_suspend, NULL, NULL)
+};
+
+static void omap4_disable_pm(void *d)
+{
+	pm_runtime_dont_use_autosuspend(d);
+	pm_runtime_disable(d);
+}
+
+static int omap4_keypad_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct omap4_keypad *keypad_data;
+	struct input_dev *input_dev;
+	unsigned int max_keys;
+	int irq;
+	int error;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	keypad_data = devm_kzalloc(dev, sizeof(*keypad_data), GFP_KERNEL);
+	if (!keypad_data) {
+		dev_err(dev, "keypad_data memory allocation failed\n");
+		return -ENOMEM;
+	}
+
+	keypad_data->irq = irq;
+	keypad_data->fck = devm_clk_get(&pdev->dev, "fck");
+	if (IS_ERR(keypad_data->fck))
+		return dev_err_probe(&pdev->dev, PTR_ERR(keypad_data->fck),
+				     "unable to get fck");
+
+	mutex_init(&keypad_data->lock);
+	platform_set_drvdata(pdev, keypad_data);
+
+	error = omap4_keypad_parse_dt(dev, keypad_data);
+	if (error)
+		return error;
+
+	keypad_data->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(keypad_data->base))
+		return PTR_ERR(keypad_data->base);
+
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_autosuspend_delay(dev, OMAP4_KEYPAD_IDLE_CHECK_MS);
+	pm_runtime_enable(dev);
+
+	error = devm_add_action_or_reset(dev, omap4_disable_pm, dev);
+	if (error) {
+		dev_err(dev, "unable to register cleanup action\n");
+		return error;
+	}
+
+	/*
+	 * Enable clocks for the keypad module so that we can read
+	 * revision register.
+	 */
+	error = pm_runtime_resume_and_get(dev);
+	if (error) {
+		dev_err(dev, "pm_runtime_resume_and_get() failed\n");
+		return error;
+	}
+
+	error = omap4_keypad_check_revision(dev, keypad_data);
+	if (!error) {
+		/* Ensure device does not raise interrupts */
+		omap4_keypad_stop(keypad_data);
+	}
+
+	pm_runtime_put_autosuspend(dev);
+	if (error)
+		return error;
+
+	/* input device allocation */
+	keypad_data->input = input_dev = devm_input_allocate_device(dev);
+	if (!input_dev)
+		return -ENOMEM;
+
+	input_dev->name = pdev->name;
+	input_dev->id.bustype = BUS_HOST;
+	input_dev->id.vendor = 0x0001;
+	input_dev->id.product = 0x0001;
+	input_dev->id.version = 0x0001;
+
+	input_dev->open = omap4_keypad_open;
+	input_dev->close = omap4_keypad_close;
+
+	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
+	if (!keypad_data->no_autorepeat)
+		__set_bit(EV_REP, input_dev->evbit);
+
+	input_set_drvdata(input_dev, keypad_data);
+
+	keypad_data->row_shift = get_count_order(keypad_data->cols);
+	max_keys = keypad_data->rows << keypad_data->row_shift;
+	keypad_data->keymap = devm_kcalloc(dev,
+					   max_keys,
+					   sizeof(keypad_data->keymap[0]),
+					   GFP_KERNEL);
+	if (!keypad_data->keymap) {
+		dev_err(dev, "Not enough memory for keymap\n");
+		return -ENOMEM;
+	}
+
+	error = matrix_keypad_build_keymap(NULL, NULL,
+					   keypad_data->rows, keypad_data->cols,
+					   keypad_data->keymap, input_dev);
+	if (error) {
+		dev_err(dev, "failed to build keymap\n");
+		return error;
+	}
+
+	error = devm_request_threaded_irq(dev, keypad_data->irq,
+					  omap4_keypad_irq_handler,
+					  omap4_keypad_irq_thread_fn,
+					  IRQF_ONESHOT,
+					  "omap4-keypad", keypad_data);
+	if (error) {
+		dev_err(dev, "failed to register interrupt\n");
+		return error;
+	}
+
+	error = input_register_device(keypad_data->input);
+	if (error) {
+		dev_err(dev, "failed to register input device\n");
+		return error;
+	}
+
+	device_init_wakeup(dev, true);
+	error = dev_pm_set_wake_irq(dev, keypad_data->irq);
+	if (error)
+		dev_warn(dev, "failed to set up wakeup irq: %d\n", error);
+
+	return 0;
+}
+
+static void omap4_keypad_remove(struct platform_device *pdev)
+{
+	dev_pm_clear_wake_irq(&pdev->dev);
+}
+
+static const struct of_device_id omap_keypad_dt_match[] = {
+	{ .compatible = "ti,omap4-keypad" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, omap_keypad_dt_match);
+
+static struct platform_driver omap4_keypad_driver = {
+	.probe		= omap4_keypad_probe,
+	.remove		= omap4_keypad_remove,
+	.driver		= {
+		.name	= "omap4-keypad",
+		.of_match_table = omap_keypad_dt_match,
+		.pm = pm_ptr(&omap4_keypad_pm_ops),
+	},
+};
+module_platform_driver(omap4_keypad_driver);
+
+MODULE_AUTHOR("Texas Instruments");
+MODULE_DESCRIPTION("OMAP4 Keypad Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:omap4-keypad");