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, 269 insertions, 0 deletions

diff --git a/drivers/bcma/driver_gpio.c b/drivers/bcma/driver_gpio.c
new file mode 100644
index 000000000..ea45222f2
--- /dev/null
+++ b/drivers/bcma/driver_gpio.c
@@ -0,0 +1,269 @@
+/*
+ * Broadcom specific AMBA
+ * GPIO driver
+ *
+ * Copyright 2011, Broadcom Corporation
+ * Copyright 2012, Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/export.h>
+#include <linux/property.h>
+
+#include <linux/bcma/bcma.h>
+
+#include "bcma_private.h"
+
+#define BCMA_GPIO_MAX_PINS	32
+
+const struct software_node bcma_gpio_swnode = {
+	.name = "bcma-gpio",
+};
+EXPORT_SYMBOL_GPL(bcma_gpio_swnode);
+
+static int bcma_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
+{
+	struct bcma_drv_cc *cc = gpiochip_get_data(chip);
+
+	return !!bcma_chipco_gpio_in(cc, 1 << gpio);
+}
+
+static int bcma_gpio_set_value(struct gpio_chip *chip, unsigned int gpio,
+			       int value)
+{
+	struct bcma_drv_cc *cc = gpiochip_get_data(chip);
+
+	bcma_chipco_gpio_out(cc, 1 << gpio, value ? 1 << gpio : 0);
+
+	return 0;
+}
+
+static int bcma_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
+{
+	struct bcma_drv_cc *cc = gpiochip_get_data(chip);
+
+	bcma_chipco_gpio_outen(cc, 1 << gpio, 0);
+	return 0;
+}
+
+static int bcma_gpio_direction_output(struct gpio_chip *chip, unsigned gpio,
+				      int value)
+{
+	struct bcma_drv_cc *cc = gpiochip_get_data(chip);
+
+	bcma_chipco_gpio_outen(cc, 1 << gpio, 1 << gpio);
+	bcma_chipco_gpio_out(cc, 1 << gpio, value ? 1 << gpio : 0);
+	return 0;
+}
+
+static int bcma_gpio_request(struct gpio_chip *chip, unsigned gpio)
+{
+	struct bcma_drv_cc *cc = gpiochip_get_data(chip);
+
+	bcma_chipco_gpio_control(cc, 1 << gpio, 0);
+	/* clear pulldown */
+	bcma_chipco_gpio_pulldown(cc, 1 << gpio, 0);
+	/* Set pullup */
+	bcma_chipco_gpio_pullup(cc, 1 << gpio, 1 << gpio);
+
+	return 0;
+}
+
+static void bcma_gpio_free(struct gpio_chip *chip, unsigned gpio)
+{
+	struct bcma_drv_cc *cc = gpiochip_get_data(chip);
+
+	/* clear pullup */
+	bcma_chipco_gpio_pullup(cc, 1 << gpio, 0);
+}
+
+#if IS_BUILTIN(CONFIG_BCM47XX) || IS_BUILTIN(CONFIG_ARCH_BCM_5301X)
+
+static void bcma_gpio_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct bcma_drv_cc *cc = gpiochip_get_data(gc);
+	int gpio = irqd_to_hwirq(d);
+	u32 val = bcma_chipco_gpio_in(cc, BIT(gpio));
+
+	gpiochip_enable_irq(gc, gpio);
+	bcma_chipco_gpio_polarity(cc, BIT(gpio), val);
+	bcma_chipco_gpio_intmask(cc, BIT(gpio), BIT(gpio));
+}
+
+static void bcma_gpio_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct bcma_drv_cc *cc = gpiochip_get_data(gc);
+	int gpio = irqd_to_hwirq(d);
+
+	bcma_chipco_gpio_intmask(cc, BIT(gpio), 0);
+	gpiochip_disable_irq(gc, gpio);
+}
+
+static const struct irq_chip bcma_gpio_irq_chip = {
+	.name		= "BCMA-GPIO",
+	.irq_mask	= bcma_gpio_irq_mask,
+	.irq_unmask	= bcma_gpio_irq_unmask,
+	.flags		= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static irqreturn_t bcma_gpio_irq_handler(int irq, void *dev_id)
+{
+	struct bcma_drv_cc *cc = dev_id;
+	struct gpio_chip *gc = &cc->gpio;
+	u32 val = bcma_cc_read32(cc, BCMA_CC_GPIOIN);
+	u32 mask = bcma_cc_read32(cc, BCMA_CC_GPIOIRQ);
+	u32 pol = bcma_cc_read32(cc, BCMA_CC_GPIOPOL);
+	unsigned long irqs = (val ^ pol) & mask;
+	int gpio;
+
+	if (!irqs)
+		return IRQ_NONE;
+
+	for_each_set_bit(gpio, &irqs, gc->ngpio)
+		generic_handle_domain_irq_safe(gc->irq.domain, gpio);
+	bcma_chipco_gpio_polarity(cc, irqs, val & irqs);
+
+	return IRQ_HANDLED;
+}
+
+static int bcma_gpio_irq_init(struct bcma_drv_cc *cc)
+{
+	struct gpio_chip *chip = &cc->gpio;
+	struct gpio_irq_chip *girq = &chip->irq;
+	int hwirq, err;
+
+	if (cc->core->bus->hosttype != BCMA_HOSTTYPE_SOC)
+		return 0;
+
+	hwirq = bcma_core_irq(cc->core, 0);
+	err = request_irq(hwirq, bcma_gpio_irq_handler, IRQF_SHARED, "gpio",
+			  cc);
+	if (err)
+		return err;
+
+	bcma_chipco_gpio_intmask(cc, ~0, 0);
+	bcma_cc_set32(cc, BCMA_CC_IRQMASK, BCMA_CC_IRQ_GPIO);
+
+	gpio_irq_chip_set_chip(girq, &bcma_gpio_irq_chip);
+	/* This will let us handle the parent IRQ in the driver */
+	girq->parent_handler = NULL;
+	girq->num_parents = 0;
+	girq->parents = NULL;
+	girq->default_type = IRQ_TYPE_NONE;
+	girq->handler = handle_simple_irq;
+
+	return 0;
+}
+
+static void bcma_gpio_irq_exit(struct bcma_drv_cc *cc)
+{
+	if (cc->core->bus->hosttype != BCMA_HOSTTYPE_SOC)
+		return;
+
+	bcma_cc_mask32(cc, BCMA_CC_IRQMASK, ~BCMA_CC_IRQ_GPIO);
+	free_irq(bcma_core_irq(cc->core, 0), cc);
+}
+#else
+static int bcma_gpio_irq_init(struct bcma_drv_cc *cc)
+{
+	return 0;
+}
+
+static void bcma_gpio_irq_exit(struct bcma_drv_cc *cc)
+{
+}
+#endif
+
+int bcma_gpio_init(struct bcma_drv_cc *cc)
+{
+	struct bcma_bus *bus = cc->core->bus;
+	struct gpio_chip *chip = &cc->gpio;
+	int err;
+
+	chip->label		= "bcma_gpio";
+	chip->owner		= THIS_MODULE;
+	chip->request		= bcma_gpio_request;
+	chip->free		= bcma_gpio_free;
+	chip->get		= bcma_gpio_get_value;
+	chip->set		= bcma_gpio_set_value;
+	chip->direction_input	= bcma_gpio_direction_input;
+	chip->direction_output	= bcma_gpio_direction_output;
+	chip->parent		= bus->dev;
+
+	/*
+	 * Register software node only for the host SoC bus, unless there is
+	 * already a firmware node assigned. There is only one SoC instance
+	 * in the system, so there are no concerns with registration conflicts.
+	 */
+	if (bus->hosttype == BCMA_HOSTTYPE_SOC && !dev_fwnode(&cc->core->dev)) {
+		err = software_node_register(&bcma_gpio_swnode);
+		if (err)
+			return err;
+		chip->fwnode = software_node_fwnode(&bcma_gpio_swnode);
+	} else {
+		chip->fwnode = dev_fwnode(&cc->core->dev);
+	}
+
+	switch (bus->chipinfo.id) {
+	case BCMA_CHIP_ID_BCM4707:
+	case BCMA_CHIP_ID_BCM5357:
+	case BCMA_CHIP_ID_BCM53572:
+	case BCMA_CHIP_ID_BCM53573:
+	case BCMA_CHIP_ID_BCM47094:
+		chip->ngpio	= 32;
+		break;
+	default:
+		chip->ngpio	= 16;
+	}
+
+	/*
+	 * Register SoC GPIO devices with absolute GPIO pin base.
+	 * On MIPS, we don't have Device Tree and we can't use relative (per chip)
+	 * GPIO numbers.
+	 * On some ARM devices, user space may want to access some system GPIO
+	 * pins directly, which is easier to do with a predictable GPIO base.
+	 */
+	if (IS_BUILTIN(CONFIG_BCM47XX) ||
+	    cc->core->bus->hosttype == BCMA_HOSTTYPE_SOC)
+		chip->base		= bus->num * BCMA_GPIO_MAX_PINS;
+	else
+		chip->base		= -1;
+
+	err = bcma_gpio_irq_init(cc);
+	if (err)
+		goto err_unregister_swnode;
+
+	err = gpiochip_add_data(chip, cc);
+	if (err)
+		goto err_irq_exit;
+
+	return 0;
+
+err_irq_exit:
+	bcma_gpio_irq_exit(cc);
+err_unregister_swnode:
+	if (bus->hosttype == BCMA_HOSTTYPE_SOC &&
+	    chip->fwnode && is_software_node(chip->fwnode)) {
+		software_node_unregister(&bcma_gpio_swnode);
+		chip->fwnode = NULL;
+	}
+	return err;
+}
+
+int bcma_gpio_unregister(struct bcma_drv_cc *cc)
+{
+	bcma_gpio_irq_exit(cc);
+	gpiochip_remove(&cc->gpio);
+	if (cc->core->bus->hosttype == BCMA_HOSTTYPE_SOC &&
+	    cc->gpio.fwnode && is_software_node(cc->gpio.fwnode)) {
+		software_node_unregister(&bcma_gpio_swnode);
+		cc->gpio.fwnode = NULL;
+	}
+	return 0;
+}