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, 149 insertions, 0 deletions

diff --git a/arch/mips/bcm63xx/gpio.c b/arch/mips/bcm63xx/gpio.c
new file mode 100644
index 000000000..ff45a6989
--- /dev/null
+++ b/arch/mips/bcm63xx/gpio.c
@@ -0,0 +1,149 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
+ * Copyright (C) 2008-2011 Florian Fainelli <florian@openwrt.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/driver.h>
+
+#include <bcm63xx_cpu.h>
+#include <bcm63xx_gpio.h>
+#include <bcm63xx_io.h>
+#include <bcm63xx_regs.h>
+
+static u32 gpio_out_low_reg;
+
+static void bcm63xx_gpio_out_low_reg_init(void)
+{
+	switch (bcm63xx_get_cpu_id()) {
+	case BCM6345_CPU_ID:
+		gpio_out_low_reg = GPIO_DATA_LO_REG_6345;
+		break;
+	default:
+		gpio_out_low_reg = GPIO_DATA_LO_REG;
+		break;
+	}
+}
+
+static DEFINE_SPINLOCK(bcm63xx_gpio_lock);
+static u32 gpio_out_low, gpio_out_high;
+
+static int bcm63xx_gpio_set(struct gpio_chip *chip, unsigned int gpio, int val)
+{
+	u32 reg;
+	u32 mask;
+	u32 *v;
+	unsigned long flags;
+
+	BUG_ON(gpio >= chip->ngpio);
+
+	if (gpio < 32) {
+		reg = gpio_out_low_reg;
+		mask = 1 << gpio;
+		v = &gpio_out_low;
+	} else {
+		reg = GPIO_DATA_HI_REG;
+		mask = 1 << (gpio - 32);
+		v = &gpio_out_high;
+	}
+
+	spin_lock_irqsave(&bcm63xx_gpio_lock, flags);
+	if (val)
+		*v |= mask;
+	else
+		*v &= ~mask;
+	bcm_gpio_writel(*v, reg);
+	spin_unlock_irqrestore(&bcm63xx_gpio_lock, flags);
+
+	return 0;
+}
+
+static int bcm63xx_gpio_get(struct gpio_chip *chip, unsigned gpio)
+{
+	u32 reg;
+	u32 mask;
+
+	BUG_ON(gpio >= chip->ngpio);
+
+	if (gpio < 32) {
+		reg = gpio_out_low_reg;
+		mask = 1 << gpio;
+	} else {
+		reg = GPIO_DATA_HI_REG;
+		mask = 1 << (gpio - 32);
+	}
+
+	return !!(bcm_gpio_readl(reg) & mask);
+}
+
+static int bcm63xx_gpio_set_direction(struct gpio_chip *chip,
+				      unsigned gpio, int dir)
+{
+	u32 reg;
+	u32 mask;
+	u32 tmp;
+	unsigned long flags;
+
+	BUG_ON(gpio >= chip->ngpio);
+
+	if (gpio < 32) {
+		reg = GPIO_CTL_LO_REG;
+		mask = 1 << gpio;
+	} else {
+		reg = GPIO_CTL_HI_REG;
+		mask = 1 << (gpio - 32);
+	}
+
+	spin_lock_irqsave(&bcm63xx_gpio_lock, flags);
+	tmp = bcm_gpio_readl(reg);
+	if (dir == BCM63XX_GPIO_DIR_IN)
+		tmp &= ~mask;
+	else
+		tmp |= mask;
+	bcm_gpio_writel(tmp, reg);
+	spin_unlock_irqrestore(&bcm63xx_gpio_lock, flags);
+
+	return 0;
+}
+
+static int bcm63xx_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
+{
+	return bcm63xx_gpio_set_direction(chip, gpio, BCM63XX_GPIO_DIR_IN);
+}
+
+static int bcm63xx_gpio_direction_output(struct gpio_chip *chip,
+					 unsigned gpio, int value)
+{
+	bcm63xx_gpio_set(chip, gpio, value);
+	return bcm63xx_gpio_set_direction(chip, gpio, BCM63XX_GPIO_DIR_OUT);
+}
+
+
+static struct gpio_chip bcm63xx_gpio_chip = {
+	.label			= "bcm63xx-gpio",
+	.direction_input	= bcm63xx_gpio_direction_input,
+	.direction_output	= bcm63xx_gpio_direction_output,
+	.get			= bcm63xx_gpio_get,
+	.set			= bcm63xx_gpio_set,
+	.base			= 0,
+};
+
+int __init bcm63xx_gpio_init(void)
+{
+	bcm63xx_gpio_out_low_reg_init();
+
+	gpio_out_low = bcm_gpio_readl(gpio_out_low_reg);
+	if (!BCMCPU_IS_6345())
+		gpio_out_high = bcm_gpio_readl(GPIO_DATA_HI_REG);
+	bcm63xx_gpio_chip.ngpio = bcm63xx_gpio_count();
+	pr_info("registering %d GPIOs\n", bcm63xx_gpio_chip.ngpio);
+
+	return gpiochip_add_data(&bcm63xx_gpio_chip, NULL);
+}