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, 287 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-altera.c b/drivers/gpio/gpio-altera.c
new file mode 100644
index 000000000..532e3360b
--- /dev/null
+++ b/drivers/gpio/gpio-altera.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2013 Altera Corporation
+ * Based on gpio-mpc8xxx.c
+ */
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include <linux/gpio/driver.h>
+#include <linux/gpio/generic.h>
+
+#define ALTERA_GPIO_MAX_NGPIO		32
+#define ALTERA_GPIO_DATA		0x0
+#define ALTERA_GPIO_DIR			0x4
+#define ALTERA_GPIO_IRQ_MASK		0x8
+#define ALTERA_GPIO_EDGE_CAP		0xc
+
+/**
+* struct altera_gpio_chip
+* @chip			: Generic GPIO chip structure.
+* @regs			: memory mapped IO address for the controller registers.
+* @gpio_lock		: synchronization lock so that new irq/set/get requests
+*			  will be blocked until the current one completes.
+* @interrupt_trigger	: specifies the hardware configured IRQ trigger type
+*			  (rising, falling, both, high)
+*/
+struct altera_gpio_chip {
+	struct gpio_generic_chip chip;
+	void __iomem *regs;
+	raw_spinlock_t gpio_lock;
+	int interrupt_trigger;
+};
+
+static void altera_gpio_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct altera_gpio_chip *altera_gc = gpiochip_get_data(gc);
+	unsigned long flags;
+	u32 intmask;
+
+	gpiochip_enable_irq(gc, irqd_to_hwirq(d));
+
+	raw_spin_lock_irqsave(&altera_gc->gpio_lock, flags);
+	intmask = readl(altera_gc->regs + ALTERA_GPIO_IRQ_MASK);
+	/* Set ALTERA_GPIO_IRQ_MASK bit to unmask */
+	intmask |= BIT(irqd_to_hwirq(d));
+	writel(intmask, altera_gc->regs + ALTERA_GPIO_IRQ_MASK);
+	raw_spin_unlock_irqrestore(&altera_gc->gpio_lock, flags);
+}
+
+static void altera_gpio_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct altera_gpio_chip *altera_gc = gpiochip_get_data(gc);
+	unsigned long flags;
+	u32 intmask;
+
+	raw_spin_lock_irqsave(&altera_gc->gpio_lock, flags);
+	intmask = readl(altera_gc->regs + ALTERA_GPIO_IRQ_MASK);
+	/* Clear ALTERA_GPIO_IRQ_MASK bit to mask */
+	intmask &= ~BIT(irqd_to_hwirq(d));
+	writel(intmask, altera_gc->regs + ALTERA_GPIO_IRQ_MASK);
+	raw_spin_unlock_irqrestore(&altera_gc->gpio_lock, flags);
+
+	gpiochip_disable_irq(gc, irqd_to_hwirq(d));
+}
+
+/*
+ * This controller's IRQ type is synthesized in hardware, so this function
+ * just checks if the requested set_type matches the synthesized IRQ type
+ */
+static int altera_gpio_irq_set_type(struct irq_data *d,
+				   unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct altera_gpio_chip *altera_gc = gpiochip_get_data(gc);
+
+	if (type == IRQ_TYPE_NONE) {
+		irq_set_handler_locked(d, handle_bad_irq);
+		return 0;
+	}
+	if (type == altera_gc->interrupt_trigger) {
+		if (type == IRQ_TYPE_LEVEL_HIGH)
+			irq_set_handler_locked(d, handle_level_irq);
+		else
+			irq_set_handler_locked(d, handle_simple_irq);
+		return 0;
+	}
+	irq_set_handler_locked(d, handle_bad_irq);
+	return -EINVAL;
+}
+
+static unsigned int altera_gpio_irq_startup(struct irq_data *d)
+{
+	altera_gpio_irq_unmask(d);
+
+	return 0;
+}
+
+static void altera_gpio_irq_edge_handler(struct irq_desc *desc)
+{
+	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
+	struct altera_gpio_chip *altera_gc = gpiochip_get_data(gc);
+	struct irq_domain *irqdomain = gc->irq.domain;
+	struct irq_chip *chip;
+	unsigned long status;
+	int i;
+
+	chip = irq_desc_get_chip(desc);
+
+	chained_irq_enter(chip, desc);
+
+	while ((status =
+	        (readl(altera_gc->regs + ALTERA_GPIO_EDGE_CAP) &
+	         readl(altera_gc->regs + ALTERA_GPIO_IRQ_MASK)))) {
+		writel(status, altera_gc->regs + ALTERA_GPIO_EDGE_CAP);
+		for_each_set_bit(i, &status, gc->ngpio)
+			generic_handle_domain_irq(irqdomain, i);
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static void altera_gpio_irq_leveL_high_handler(struct irq_desc *desc)
+{
+	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
+	struct altera_gpio_chip *altera_gc = gpiochip_get_data(gc);
+	struct irq_domain *irqdomain = gc->irq.domain;
+	struct irq_chip *chip;
+	unsigned long status;
+	int i;
+
+	chip = irq_desc_get_chip(desc);
+
+	chained_irq_enter(chip, desc);
+
+	status = readl(altera_gc->regs + ALTERA_GPIO_DATA);
+	status &= readl(altera_gc->regs + ALTERA_GPIO_IRQ_MASK);
+
+	for_each_set_bit(i, &status, gc->ngpio)
+		generic_handle_domain_irq(irqdomain, i);
+
+	chained_irq_exit(chip, desc);
+}
+
+static const struct irq_chip altera_gpio_irq_chip = {
+	.name = "altera-gpio",
+	.irq_mask = altera_gpio_irq_mask,
+	.irq_unmask = altera_gpio_irq_unmask,
+	.irq_set_type = altera_gpio_irq_set_type,
+	.irq_startup  = altera_gpio_irq_startup,
+	.irq_shutdown = altera_gpio_irq_mask,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int altera_gpio_probe(struct platform_device *pdev)
+{
+	struct gpio_generic_chip_config config;
+	struct device *dev = &pdev->dev;
+	int reg, ret;
+	struct altera_gpio_chip *altera_gc;
+	struct gpio_generic_chip *chip;
+	struct gpio_chip *gc;
+	struct gpio_irq_chip *girq;
+	int mapped_irq;
+
+	altera_gc = devm_kzalloc(&pdev->dev, sizeof(*altera_gc), GFP_KERNEL);
+	if (!altera_gc)
+		return -ENOMEM;
+
+	raw_spin_lock_init(&altera_gc->gpio_lock);
+
+	altera_gc->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(altera_gc->regs))
+		return dev_err_probe(dev, PTR_ERR(altera_gc->regs),
+				     "failed to ioremap memory resource\n");
+
+	chip = &altera_gc->chip;
+
+	config = (struct gpio_generic_chip_config) {
+		.dev = dev,
+		.sz = 4,
+		.dat = altera_gc->regs + ALTERA_GPIO_DATA,
+		.set = altera_gc->regs + ALTERA_GPIO_DATA,
+		.dirout = altera_gc->regs + ALTERA_GPIO_DIR,
+	};
+
+	ret = gpio_generic_chip_init(chip, &config);
+	if (ret)
+		return dev_err_probe(dev, ret, "unable to init generic GPIO\n");
+
+	gc = &chip->gc;
+
+	if (device_property_read_u32(dev, "altr,ngpio", &reg))
+		/* By default assume maximum ngpio */
+		gc->ngpio = ALTERA_GPIO_MAX_NGPIO;
+	else
+		gc->ngpio = reg;
+
+	if (gc->ngpio > ALTERA_GPIO_MAX_NGPIO) {
+		dev_warn(&pdev->dev,
+			"ngpio is greater than %d, defaulting to %d\n",
+			ALTERA_GPIO_MAX_NGPIO, ALTERA_GPIO_MAX_NGPIO);
+		gc->ngpio = ALTERA_GPIO_MAX_NGPIO;
+	}
+
+	gc->base = -1;
+	gc->label = devm_kasprintf(dev, GFP_KERNEL, "%pfw", dev_fwnode(dev));
+	if (!gc->label)
+		return -ENOMEM;
+
+	mapped_irq = platform_get_irq_optional(pdev, 0);
+	if (mapped_irq < 0)
+		goto skip_irq;
+
+	if (device_property_read_u32(dev, "altr,interrupt-type", &reg)) {
+		dev_err(&pdev->dev,
+			"altr,interrupt-type value not set in device tree\n");
+		return -EINVAL;
+	}
+	altera_gc->interrupt_trigger = reg;
+
+	girq = &gc->irq;
+	gpio_irq_chip_set_chip(girq, &altera_gpio_irq_chip);
+
+	if (altera_gc->interrupt_trigger == IRQ_TYPE_LEVEL_HIGH)
+		girq->parent_handler = altera_gpio_irq_leveL_high_handler;
+	else
+		girq->parent_handler = altera_gpio_irq_edge_handler;
+	girq->num_parents = 1;
+	girq->parents = devm_kcalloc(&pdev->dev, 1, sizeof(*girq->parents),
+				     GFP_KERNEL);
+	if (!girq->parents)
+		return -ENOMEM;
+	girq->default_type = IRQ_TYPE_NONE;
+	girq->handler = handle_bad_irq;
+	girq->parents[0] = mapped_irq;
+
+skip_irq:
+	ret = devm_gpiochip_add_data(dev, gc, altera_gc);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed adding memory mapped gpiochip\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id altera_gpio_of_match[] = {
+	{ .compatible = "altr,pio-1.0", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, altera_gpio_of_match);
+
+static struct platform_driver altera_gpio_driver = {
+	.driver = {
+		.name	= "altera_gpio",
+		.of_match_table = altera_gpio_of_match,
+	},
+	.probe		= altera_gpio_probe,
+};
+
+static int __init altera_gpio_init(void)
+{
+	return platform_driver_register(&altera_gpio_driver);
+}
+subsys_initcall(altera_gpio_init);
+
+static void __exit altera_gpio_exit(void)
+{
+	platform_driver_unregister(&altera_gpio_driver);
+}
+module_exit(altera_gpio_exit);
+
+MODULE_AUTHOR("Tien Hock Loh <thloh@altera.com>");
+MODULE_DESCRIPTION("Altera GPIO driver");
+MODULE_LICENSE("GPL");