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, 355 insertions, 0 deletions

diff --git a/drivers/pinctrl/mediatek/pinctrl-mtmips.c b/drivers/pinctrl/mediatek/pinctrl-mtmips.c
new file mode 100644
index 000000000..b2d7a79ff
--- /dev/null
+++ b/drivers/pinctrl/mediatek/pinctrl-mtmips.c
@@ -0,0 +1,355 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/pinctrl/machine.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+#include <asm/mach-ralink/mt7620.h>
+
+#include "pinctrl-mtmips.h"
+#include "../core.h"
+#include "../pinctrl-utils.h"
+
+#define SYSC_REG_GPIO_MODE	0x60
+#define SYSC_REG_GPIO_MODE2	0x64
+
+struct mtmips_priv {
+	struct device *dev;
+
+	struct pinctrl_pin_desc *pads;
+	struct pinctrl_desc *desc;
+
+	struct mtmips_pmx_func **func;
+	int func_count;
+
+	struct mtmips_pmx_group *groups;
+	const char **group_names;
+	int group_count;
+
+	u8 *gpio;
+	int max_pins;
+};
+
+static int mtmips_get_group_count(struct pinctrl_dev *pctrldev)
+{
+	struct mtmips_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	return p->group_count;
+}
+
+static const char *mtmips_get_group_name(struct pinctrl_dev *pctrldev,
+					 unsigned int group)
+{
+	struct mtmips_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	return (group >= p->group_count) ? NULL : p->group_names[group];
+}
+
+static int mtmips_get_group_pins(struct pinctrl_dev *pctrldev,
+				 unsigned int group,
+				 const unsigned int **pins,
+				 unsigned int *num_pins)
+{
+	struct mtmips_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	if (group >= p->group_count)
+		return -EINVAL;
+
+	*pins = p->groups[group].func[0].pins;
+	*num_pins = p->groups[group].func[0].pin_count;
+
+	return 0;
+}
+
+static const struct pinctrl_ops mtmips_pctrl_ops = {
+	.get_groups_count	= mtmips_get_group_count,
+	.get_group_name		= mtmips_get_group_name,
+	.get_group_pins		= mtmips_get_group_pins,
+	.dt_node_to_map		= pinconf_generic_dt_node_to_map_all,
+	.dt_free_map		= pinconf_generic_dt_free_map,
+};
+
+static int mtmips_pmx_func_count(struct pinctrl_dev *pctrldev)
+{
+	struct mtmips_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	return p->func_count;
+}
+
+static const char *mtmips_pmx_func_name(struct pinctrl_dev *pctrldev,
+					unsigned int func)
+{
+	struct mtmips_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	return p->func[func]->name;
+}
+
+static int mtmips_pmx_group_get_groups(struct pinctrl_dev *pctrldev,
+				       unsigned int func,
+				       const char * const **groups,
+				       unsigned int * const num_groups)
+{
+	struct mtmips_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	if (p->func[func]->group_count == 1)
+		*groups = &p->group_names[p->func[func]->groups[0]];
+	else
+		*groups = p->group_names;
+
+	*num_groups = p->func[func]->group_count;
+
+	return 0;
+}
+
+static int mtmips_pmx_group_enable(struct pinctrl_dev *pctrldev,
+				   unsigned int func, unsigned int group)
+{
+	struct mtmips_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+	u32 mode = 0;
+	u32 reg = SYSC_REG_GPIO_MODE;
+	int i;
+	int shift;
+
+	/* dont allow double use */
+	if (p->groups[group].enabled) {
+		dev_err(p->dev, "%s is already enabled\n",
+			p->groups[group].name);
+		return 0;
+	}
+
+	p->groups[group].enabled = 1;
+	p->func[func]->enabled = 1;
+
+	shift = p->groups[group].shift;
+	if (shift >= 32) {
+		shift -= 32;
+		reg = SYSC_REG_GPIO_MODE2;
+	}
+	mode = rt_sysc_r32(reg);
+	mode &= ~(p->groups[group].mask << shift);
+
+	/* mark the pins as gpio */
+	for (i = 0; i < p->groups[group].func[0].pin_count; i++)
+		p->gpio[p->groups[group].func[0].pins[i]] = 1;
+
+	/* function 0 is gpio and needs special handling */
+	if (func == 0) {
+		mode |= p->groups[group].gpio << shift;
+	} else {
+		for (i = 0; i < p->func[func]->pin_count; i++)
+			p->gpio[p->func[func]->pins[i]] = 0;
+		mode |= p->func[func]->value << shift;
+	}
+	rt_sysc_w32(mode, reg);
+
+	return 0;
+}
+
+static int mtmips_pmx_group_gpio_request_enable(struct pinctrl_dev *pctrldev,
+						struct pinctrl_gpio_range *range,
+						unsigned int pin)
+{
+	struct mtmips_priv *p = pinctrl_dev_get_drvdata(pctrldev);
+
+	if (!p->gpio[pin]) {
+		dev_err(p->dev, "pin %d is not set to gpio mux\n", pin);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct pinmux_ops mtmips_pmx_group_ops = {
+	.get_functions_count	= mtmips_pmx_func_count,
+	.get_function_name	= mtmips_pmx_func_name,
+	.get_function_groups	= mtmips_pmx_group_get_groups,
+	.set_mux		= mtmips_pmx_group_enable,
+	.gpio_request_enable	= mtmips_pmx_group_gpio_request_enable,
+};
+
+static struct pinctrl_desc mtmips_pctrl_desc = {
+	.owner		= THIS_MODULE,
+	.name		= "mtmips-pinctrl",
+	.pctlops	= &mtmips_pctrl_ops,
+	.pmxops		= &mtmips_pmx_group_ops,
+};
+
+static struct mtmips_pmx_func gpio_func = {
+	.name = "gpio",
+};
+
+static int mtmips_pinctrl_index(struct mtmips_priv *p)
+{
+	struct mtmips_pmx_group *mux = p->groups;
+	int i, j, c = 0;
+
+	/* count the mux functions */
+	while (mux->name) {
+		p->group_count++;
+		mux++;
+	}
+
+	/* allocate the group names array needed by the gpio function */
+	p->group_names = devm_kcalloc(p->dev, p->group_count,
+				      sizeof(char *), GFP_KERNEL);
+	if (!p->group_names)
+		return -ENOMEM;
+
+	for (i = 0; i < p->group_count; i++) {
+		p->group_names[i] = p->groups[i].name;
+		p->func_count += p->groups[i].func_count;
+	}
+
+	/* we have a dummy function[0] for gpio */
+	p->func_count++;
+
+	/* allocate our function and group mapping index buffers */
+	p->func = devm_kcalloc(p->dev, p->func_count,
+			       sizeof(*p->func), GFP_KERNEL);
+	gpio_func.groups = devm_kcalloc(p->dev, p->group_count, sizeof(int),
+					GFP_KERNEL);
+	if (!p->func || !gpio_func.groups)
+		return -ENOMEM;
+
+	/* add a backpointer to the function so it knows its group */
+	gpio_func.group_count = p->group_count;
+	for (i = 0; i < gpio_func.group_count; i++)
+		gpio_func.groups[i] = i;
+
+	p->func[c] = &gpio_func;
+	c++;
+
+	/* add remaining functions */
+	for (i = 0; i < p->group_count; i++) {
+		for (j = 0; j < p->groups[i].func_count; j++) {
+			p->func[c] = &p->groups[i].func[j];
+			p->func[c]->groups = devm_kzalloc(p->dev, sizeof(int),
+						    GFP_KERNEL);
+			if (!p->func[c]->groups)
+				return -ENOMEM;
+			p->func[c]->groups[0] = i;
+			p->func[c]->group_count = 1;
+			c++;
+		}
+	}
+	return 0;
+}
+
+static int mtmips_pinctrl_pins(struct mtmips_priv *p)
+{
+	int i, j;
+
+	/*
+	 * loop over the functions and initialize the pins array.
+	 * also work out the highest pin used.
+	 */
+	for (i = 0; i < p->func_count; i++) {
+		int pin;
+
+		if (!p->func[i]->pin_count)
+			continue;
+
+		p->func[i]->pins = devm_kcalloc(p->dev,
+						p->func[i]->pin_count,
+						sizeof(int),
+						GFP_KERNEL);
+		if (!p->func[i]->pins)
+			return -ENOMEM;
+		for (j = 0; j < p->func[i]->pin_count; j++)
+			p->func[i]->pins[j] = p->func[i]->pin_first + j;
+
+		pin = p->func[i]->pin_first + p->func[i]->pin_count;
+		if (pin > p->max_pins)
+			p->max_pins = pin;
+	}
+
+	/* the buffer that tells us which pins are gpio */
+	p->gpio = devm_kcalloc(p->dev, p->max_pins, sizeof(u8), GFP_KERNEL);
+	/* the pads needed to tell pinctrl about our pins */
+	p->pads = devm_kcalloc(p->dev, p->max_pins,
+			       sizeof(struct pinctrl_pin_desc), GFP_KERNEL);
+	if (!p->pads || !p->gpio)
+		return -ENOMEM;
+
+	memset(p->gpio, 1, sizeof(u8) * p->max_pins);
+	for (i = 0; i < p->func_count; i++) {
+		if (!p->func[i]->pin_count)
+			continue;
+
+		for (j = 0; j < p->func[i]->pin_count; j++)
+			p->gpio[p->func[i]->pins[j]] = 0;
+	}
+
+	/* pin 0 is always a gpio */
+	p->gpio[0] = 1;
+
+	/* set the pads */
+	for (i = 0; i < p->max_pins; i++) {
+		/* strlen("ioXY") + 1 = 5 */
+		char *name = devm_kzalloc(p->dev, 5, GFP_KERNEL);
+
+		if (!name)
+			return -ENOMEM;
+		snprintf(name, 5, "io%d", i);
+		p->pads[i].number = i;
+		p->pads[i].name = name;
+	}
+	p->desc->pins = p->pads;
+	p->desc->npins = p->max_pins;
+
+	return 0;
+}
+
+int mtmips_pinctrl_init(struct platform_device *pdev,
+			struct mtmips_pmx_group *data)
+{
+	struct mtmips_priv *p;
+	struct pinctrl_dev *dev;
+	int err;
+
+	if (!data)
+		return -ENOTSUPP;
+
+	/* setup the private data */
+	p = devm_kzalloc(&pdev->dev, sizeof(struct mtmips_priv), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	p->dev = &pdev->dev;
+	p->desc = &mtmips_pctrl_desc;
+	p->groups = data;
+	platform_set_drvdata(pdev, p);
+
+	/* init the device */
+	err = mtmips_pinctrl_index(p);
+	if (err) {
+		dev_err(&pdev->dev, "failed to load index\n");
+		return err;
+	}
+
+	err = mtmips_pinctrl_pins(p);
+	if (err) {
+		dev_err(&pdev->dev, "failed to load pins\n");
+		return err;
+	}
+	dev = pinctrl_register(p->desc, &pdev->dev, p);
+
+	return PTR_ERR_OR_ZERO(dev);
+}
+EXPORT_SYMBOL_NS_GPL(mtmips_pinctrl_init, "MTK_PINCTRL");
+
+MODULE_DESCRIPTION("MediaTek MIPS Pinctrl Common Driver");
+MODULE_LICENSE("GPL v2");