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, 327 insertions, 0 deletions

diff --git a/drivers/input/keyboard/spear-keyboard.c b/drivers/input/keyboard/spear-keyboard.c
new file mode 100644
index 000000000..53f3ac64c
--- /dev/null
+++ b/drivers/input/keyboard/spear-keyboard.c
@@ -0,0 +1,327 @@
+/*
+ * SPEAr Keyboard Driver
+ * Based on omap-keypad driver
+ *
+ * Copyright (C) 2010 ST Microelectronics
+ * Rajeev Kumar <rajeevkumar.linux@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+/* Keyboard Registers */
+#define MODE_CTL_REG	0x00
+#define STATUS_REG	0x0C
+#define DATA_REG	0x10
+#define INTR_MASK	0x54
+
+/* Register Values */
+#define NUM_ROWS	16
+#define NUM_COLS	16
+#define MODE_CTL_PCLK_FREQ_SHIFT	9
+#define MODE_CTL_PCLK_FREQ_MSK		0x7F
+
+#define MODE_CTL_KEYBOARD	(0x2 << 0)
+#define MODE_CTL_SCAN_RATE_10	(0x0 << 2)
+#define MODE_CTL_SCAN_RATE_20	(0x1 << 2)
+#define MODE_CTL_SCAN_RATE_40	(0x2 << 2)
+#define MODE_CTL_SCAN_RATE_80	(0x3 << 2)
+#define MODE_CTL_KEYNUM_SHIFT	6
+#define MODE_CTL_START_SCAN	(0x1 << 8)
+
+#define STATUS_DATA_AVAIL	(0x1 << 1)
+
+#define DATA_ROW_MASK		0xF0
+#define DATA_COLUMN_MASK	0x0F
+
+#define ROW_SHIFT		4
+
+struct spear_kbd {
+	struct input_dev *input;
+	void __iomem *io_base;
+	struct clk *clk;
+	unsigned int irq;
+	u32 mode;
+	u32 suspended_rate;
+	u32 mode_ctl_reg;
+	unsigned short last_key;
+	unsigned short keycodes[NUM_ROWS * NUM_COLS];
+	bool irq_wake_enabled;
+};
+
+static irqreturn_t spear_kbd_interrupt(int irq, void *dev_id)
+{
+	struct spear_kbd *kbd = dev_id;
+	struct input_dev *input = kbd->input;
+	unsigned int key;
+	u32 sts, val;
+
+	sts = readl_relaxed(kbd->io_base + STATUS_REG);
+	if (!(sts & STATUS_DATA_AVAIL))
+		return IRQ_NONE;
+
+	if (kbd->last_key != KEY_RESERVED) {
+		input_report_key(input, kbd->last_key, 0);
+		kbd->last_key = KEY_RESERVED;
+	}
+
+	/* following reads active (row, col) pair */
+	val = readl_relaxed(kbd->io_base + DATA_REG) &
+		(DATA_ROW_MASK | DATA_COLUMN_MASK);
+	key = kbd->keycodes[val];
+
+	input_event(input, EV_MSC, MSC_SCAN, val);
+	input_report_key(input, key, 1);
+	input_sync(input);
+
+	kbd->last_key = key;
+
+	/* clear interrupt */
+	writel_relaxed(0, kbd->io_base + STATUS_REG);
+
+	return IRQ_HANDLED;
+}
+
+static int spear_kbd_open(struct input_dev *dev)
+{
+	struct spear_kbd *kbd = input_get_drvdata(dev);
+	int error;
+	u32 val;
+
+	kbd->last_key = KEY_RESERVED;
+
+	error = clk_enable(kbd->clk);
+	if (error)
+		return error;
+
+	/* keyboard rate to be programmed is input clock (in MHz) - 1 */
+	val = clk_get_rate(kbd->clk) / 1000000 - 1;
+	val = (val & MODE_CTL_PCLK_FREQ_MSK) << MODE_CTL_PCLK_FREQ_SHIFT;
+
+	/* program keyboard */
+	val = MODE_CTL_SCAN_RATE_80 | MODE_CTL_KEYBOARD | val |
+		(kbd->mode << MODE_CTL_KEYNUM_SHIFT);
+	writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
+	writel_relaxed(1, kbd->io_base + STATUS_REG);
+
+	/* start key scan */
+	val = readl_relaxed(kbd->io_base + MODE_CTL_REG);
+	val |= MODE_CTL_START_SCAN;
+	writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
+
+	return 0;
+}
+
+static void spear_kbd_close(struct input_dev *dev)
+{
+	struct spear_kbd *kbd = input_get_drvdata(dev);
+	u32 val;
+
+	/* stop key scan */
+	val = readl_relaxed(kbd->io_base + MODE_CTL_REG);
+	val &= ~MODE_CTL_START_SCAN;
+	writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
+
+	clk_disable(kbd->clk);
+
+	kbd->last_key = KEY_RESERVED;
+}
+
+static int spear_kbd_probe(struct platform_device *pdev)
+{
+	struct spear_kbd *kbd;
+	struct input_dev *input_dev;
+	int irq;
+	int error;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	kbd = devm_kzalloc(&pdev->dev, sizeof(*kbd), GFP_KERNEL);
+	if (!kbd) {
+		dev_err(&pdev->dev, "not enough memory for driver data\n");
+		return -ENOMEM;
+	}
+
+	error = device_property_read_u32(&pdev->dev, "st,mode", &kbd->mode);
+	if (error) {
+		dev_err(&pdev->dev, "Invalid or missing mode\n");
+		return error;
+	}
+
+	device_property_read_u32(&pdev->dev, "suspended_rate", &kbd->suspended_rate);
+
+	input_dev = devm_input_allocate_device(&pdev->dev);
+	if (!input_dev) {
+		dev_err(&pdev->dev, "unable to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	kbd->input = input_dev;
+	kbd->irq = irq;
+
+	kbd->io_base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
+	if (IS_ERR(kbd->io_base))
+		return PTR_ERR(kbd->io_base);
+
+	kbd->clk = devm_clk_get_prepared(&pdev->dev, NULL);
+	if (IS_ERR(kbd->clk))
+		return PTR_ERR(kbd->clk);
+
+	input_dev->name = "Spear Keyboard";
+	input_dev->phys = "keyboard/input0";
+	input_dev->id.bustype = BUS_HOST;
+	input_dev->id.vendor = 0x0001;
+	input_dev->id.product = 0x0001;
+	input_dev->id.version = 0x0100;
+	input_dev->open = spear_kbd_open;
+	input_dev->close = spear_kbd_close;
+
+	error = matrix_keypad_build_keymap(NULL, NULL, NUM_ROWS, NUM_COLS,
+					   kbd->keycodes, input_dev);
+	if (error) {
+		dev_err(&pdev->dev, "Failed to build keymap\n");
+		return error;
+	}
+
+	if (device_property_read_bool(&pdev->dev, "autorepeat"))
+		__set_bit(EV_REP, input_dev->evbit);
+	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
+
+	input_set_drvdata(input_dev, kbd);
+
+	error = devm_request_irq(&pdev->dev, irq, spear_kbd_interrupt, 0,
+				 "keyboard", kbd);
+	if (error) {
+		dev_err(&pdev->dev, "request_irq failed\n");
+		return error;
+	}
+
+	error = input_register_device(input_dev);
+	if (error) {
+		dev_err(&pdev->dev, "Unable to register keyboard device\n");
+		return error;
+	}
+
+	device_init_wakeup(&pdev->dev, 1);
+	platform_set_drvdata(pdev, kbd);
+
+	return 0;
+}
+
+static int spear_kbd_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct spear_kbd *kbd = platform_get_drvdata(pdev);
+	struct input_dev *input_dev = kbd->input;
+	unsigned int rate = 0, mode_ctl_reg, val;
+
+	guard(mutex)(&input_dev->mutex);
+
+	/* explicitly enable clock as we may program device */
+	clk_enable(kbd->clk);
+
+	mode_ctl_reg = readl_relaxed(kbd->io_base + MODE_CTL_REG);
+
+	if (device_may_wakeup(&pdev->dev)) {
+		if (!enable_irq_wake(kbd->irq))
+			kbd->irq_wake_enabled = true;
+
+		/*
+		 * reprogram the keyboard operating frequency as on some
+		 * platform it may change during system suspended
+		 */
+		if (kbd->suspended_rate)
+			rate = kbd->suspended_rate / 1000000 - 1;
+		else
+			rate = clk_get_rate(kbd->clk) / 1000000 - 1;
+
+		val = mode_ctl_reg &
+			~(MODE_CTL_PCLK_FREQ_MSK << MODE_CTL_PCLK_FREQ_SHIFT);
+		val |= (rate & MODE_CTL_PCLK_FREQ_MSK)
+			<< MODE_CTL_PCLK_FREQ_SHIFT;
+		writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
+
+	} else {
+		if (input_device_enabled(input_dev)) {
+			writel_relaxed(mode_ctl_reg & ~MODE_CTL_START_SCAN,
+					kbd->io_base + MODE_CTL_REG);
+			clk_disable(kbd->clk);
+		}
+	}
+
+	/* store current configuration */
+	if (input_device_enabled(input_dev))
+		kbd->mode_ctl_reg = mode_ctl_reg;
+
+	/* restore previous clk state */
+	clk_disable(kbd->clk);
+
+	return 0;
+}
+
+static int spear_kbd_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct spear_kbd *kbd = platform_get_drvdata(pdev);
+	struct input_dev *input_dev = kbd->input;
+
+	guard(mutex)(&input_dev->mutex);
+
+	if (device_may_wakeup(&pdev->dev)) {
+		if (kbd->irq_wake_enabled) {
+			kbd->irq_wake_enabled = false;
+			disable_irq_wake(kbd->irq);
+		}
+	} else {
+		if (input_device_enabled(input_dev))
+			clk_enable(kbd->clk);
+	}
+
+	/* restore current configuration */
+	if (input_device_enabled(input_dev))
+		writel_relaxed(kbd->mode_ctl_reg, kbd->io_base + MODE_CTL_REG);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(spear_kbd_pm_ops,
+				spear_kbd_suspend, spear_kbd_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id spear_kbd_id_table[] = {
+	{ .compatible = "st,spear300-kbd" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, spear_kbd_id_table);
+#endif
+
+static struct platform_driver spear_kbd_driver = {
+	.probe		= spear_kbd_probe,
+	.driver		= {
+		.name	= "keyboard",
+		.pm	= pm_sleep_ptr(&spear_kbd_pm_ops),
+		.of_match_table = of_match_ptr(spear_kbd_id_table),
+	},
+};
+module_platform_driver(spear_kbd_driver);
+
+MODULE_AUTHOR("Rajeev Kumar");
+MODULE_DESCRIPTION("SPEAr Keyboard Driver");
+MODULE_LICENSE("GPL");