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, 561 insertions, 0 deletions

diff --git a/drivers/mfd/stmfx.c b/drivers/mfd/stmfx.c
new file mode 100644
index 000000000..f683fdb6e
--- /dev/null
+++ b/drivers/mfd/stmfx.c
@@ -0,0 +1,561 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for STMicroelectronics Multi-Function eXpander (STMFX) core
+ *
+ * Copyright (C) 2019 STMicroelectronics
+ * Author(s): Amelie Delaunay <amelie.delaunay@st.com>.
+ */
+#include <linux/bitfield.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/stmfx.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+
+static bool stmfx_reg_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case STMFX_REG_SYS_CTRL:
+	case STMFX_REG_IRQ_SRC_EN:
+	case STMFX_REG_IRQ_PENDING:
+	case STMFX_REG_IRQ_GPI_PENDING1:
+	case STMFX_REG_IRQ_GPI_PENDING2:
+	case STMFX_REG_IRQ_GPI_PENDING3:
+	case STMFX_REG_GPIO_STATE1:
+	case STMFX_REG_GPIO_STATE2:
+	case STMFX_REG_GPIO_STATE3:
+	case STMFX_REG_IRQ_GPI_SRC1:
+	case STMFX_REG_IRQ_GPI_SRC2:
+	case STMFX_REG_IRQ_GPI_SRC3:
+	case STMFX_REG_GPO_SET1:
+	case STMFX_REG_GPO_SET2:
+	case STMFX_REG_GPO_SET3:
+	case STMFX_REG_GPO_CLR1:
+	case STMFX_REG_GPO_CLR2:
+	case STMFX_REG_GPO_CLR3:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool stmfx_reg_writeable(struct device *dev, unsigned int reg)
+{
+	return (reg >= STMFX_REG_SYS_CTRL);
+}
+
+static const struct regmap_config stmfx_regmap_config = {
+	.reg_bits	= 8,
+	.reg_stride	= 1,
+	.val_bits	= 8,
+	.max_register	= STMFX_REG_MAX,
+	.volatile_reg	= stmfx_reg_volatile,
+	.writeable_reg	= stmfx_reg_writeable,
+	.cache_type	= REGCACHE_MAPLE,
+};
+
+static const struct resource stmfx_pinctrl_resources[] = {
+	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_GPIO),
+};
+
+static const struct resource stmfx_idd_resources[] = {
+	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_IDD),
+	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_ERROR),
+};
+
+static const struct resource stmfx_ts_resources[] = {
+	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_DET),
+	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_NE),
+	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_TH),
+	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_FULL),
+	DEFINE_RES_IRQ(STMFX_REG_IRQ_SRC_EN_TS_OVF),
+};
+
+static struct mfd_cell stmfx_cells[] = {
+	{
+		.of_compatible = "st,stmfx-0300-pinctrl",
+		.name = "stmfx-pinctrl",
+		.resources = stmfx_pinctrl_resources,
+		.num_resources = ARRAY_SIZE(stmfx_pinctrl_resources),
+	},
+	{
+		.of_compatible = "st,stmfx-0300-idd",
+		.name = "stmfx-idd",
+		.resources = stmfx_idd_resources,
+		.num_resources = ARRAY_SIZE(stmfx_idd_resources),
+	},
+	{
+		.of_compatible = "st,stmfx-0300-ts",
+		.name = "stmfx-ts",
+		.resources = stmfx_ts_resources,
+		.num_resources = ARRAY_SIZE(stmfx_ts_resources),
+	},
+};
+
+static u8 stmfx_func_to_mask(u32 func)
+{
+	u8 mask = 0;
+
+	if (func & STMFX_FUNC_GPIO)
+		mask |= STMFX_REG_SYS_CTRL_GPIO_EN;
+
+	if ((func & STMFX_FUNC_ALTGPIO_LOW) || (func & STMFX_FUNC_ALTGPIO_HIGH))
+		mask |= STMFX_REG_SYS_CTRL_ALTGPIO_EN;
+
+	if (func & STMFX_FUNC_TS)
+		mask |= STMFX_REG_SYS_CTRL_TS_EN;
+
+	if (func & STMFX_FUNC_IDD)
+		mask |= STMFX_REG_SYS_CTRL_IDD_EN;
+
+	return mask;
+}
+
+int stmfx_function_enable(struct stmfx *stmfx, u32 func)
+{
+	u32 sys_ctrl;
+	u8 mask;
+	int ret;
+
+	ret = regmap_read(stmfx->map, STMFX_REG_SYS_CTRL, &sys_ctrl);
+	if (ret)
+		return ret;
+
+	/*
+	 * IDD and TS have priority in STMFX FW, so if IDD and TS are enabled,
+	 * ALTGPIO function is disabled by STMFX FW. If IDD or TS is enabled,
+	 * the number of aGPIO available decreases. To avoid GPIO management
+	 * disturbance, abort IDD or TS function enable in this case.
+	 */
+	if (((func & STMFX_FUNC_IDD) || (func & STMFX_FUNC_TS)) &&
+	    (sys_ctrl & STMFX_REG_SYS_CTRL_ALTGPIO_EN)) {
+		dev_err(stmfx->dev, "ALTGPIO function already enabled\n");
+		return -EBUSY;
+	}
+
+	/* If TS is enabled, aGPIO[3:0] cannot be used */
+	if ((func & STMFX_FUNC_ALTGPIO_LOW) &&
+	    (sys_ctrl & STMFX_REG_SYS_CTRL_TS_EN)) {
+		dev_err(stmfx->dev, "TS in use, aGPIO[3:0] unavailable\n");
+		return -EBUSY;
+	}
+
+	/* If IDD is enabled, aGPIO[7:4] cannot be used */
+	if ((func & STMFX_FUNC_ALTGPIO_HIGH) &&
+	    (sys_ctrl & STMFX_REG_SYS_CTRL_IDD_EN)) {
+		dev_err(stmfx->dev, "IDD in use, aGPIO[7:4] unavailable\n");
+		return -EBUSY;
+	}
+
+	mask = stmfx_func_to_mask(func);
+
+	return regmap_update_bits(stmfx->map, STMFX_REG_SYS_CTRL, mask, mask);
+}
+EXPORT_SYMBOL_GPL(stmfx_function_enable);
+
+int stmfx_function_disable(struct stmfx *stmfx, u32 func)
+{
+	u8 mask = stmfx_func_to_mask(func);
+
+	return regmap_update_bits(stmfx->map, STMFX_REG_SYS_CTRL, mask, 0);
+}
+EXPORT_SYMBOL_GPL(stmfx_function_disable);
+
+static void stmfx_irq_bus_lock(struct irq_data *data)
+{
+	struct stmfx *stmfx = irq_data_get_irq_chip_data(data);
+
+	mutex_lock(&stmfx->lock);
+}
+
+static void stmfx_irq_bus_sync_unlock(struct irq_data *data)
+{
+	struct stmfx *stmfx = irq_data_get_irq_chip_data(data);
+
+	regmap_write(stmfx->map, STMFX_REG_IRQ_SRC_EN, stmfx->irq_src);
+
+	mutex_unlock(&stmfx->lock);
+}
+
+static void stmfx_irq_mask(struct irq_data *data)
+{
+	struct stmfx *stmfx = irq_data_get_irq_chip_data(data);
+
+	stmfx->irq_src &= ~BIT(data->hwirq % 8);
+}
+
+static void stmfx_irq_unmask(struct irq_data *data)
+{
+	struct stmfx *stmfx = irq_data_get_irq_chip_data(data);
+
+	stmfx->irq_src |= BIT(data->hwirq % 8);
+}
+
+static struct irq_chip stmfx_irq_chip = {
+	.name			= "stmfx-core",
+	.irq_bus_lock		= stmfx_irq_bus_lock,
+	.irq_bus_sync_unlock	= stmfx_irq_bus_sync_unlock,
+	.irq_mask		= stmfx_irq_mask,
+	.irq_unmask		= stmfx_irq_unmask,
+};
+
+static irqreturn_t stmfx_irq_handler(int irq, void *data)
+{
+	struct stmfx *stmfx = data;
+	unsigned long bits;
+	u32 pending, ack;
+	int n, ret;
+
+	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING, &pending);
+	if (ret)
+		return IRQ_NONE;
+
+	/*
+	 * There is no ACK for GPIO, MFX_REG_IRQ_PENDING_GPIO is a logical OR
+	 * of MFX_REG_IRQ_GPI _PENDING1/_PENDING2/_PENDING3
+	 */
+	ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
+	if (ack) {
+		ret = regmap_write(stmfx->map, STMFX_REG_IRQ_ACK, ack);
+		if (ret)
+			return IRQ_NONE;
+	}
+
+	bits = pending;
+	for_each_set_bit(n, &bits, STMFX_REG_IRQ_SRC_MAX)
+		handle_nested_irq(irq_find_mapping(stmfx->irq_domain, n));
+
+	return IRQ_HANDLED;
+}
+
+static int stmfx_irq_map(struct irq_domain *d, unsigned int virq,
+			 irq_hw_number_t hwirq)
+{
+	irq_set_chip_data(virq, d->host_data);
+	irq_set_chip_and_handler(virq, &stmfx_irq_chip, handle_simple_irq);
+	irq_set_nested_thread(virq, 1);
+	irq_set_noprobe(virq);
+
+	return 0;
+}
+
+static void stmfx_irq_unmap(struct irq_domain *d, unsigned int virq)
+{
+	irq_set_chip_and_handler(virq, NULL, NULL);
+	irq_set_chip_data(virq, NULL);
+}
+
+static const struct irq_domain_ops stmfx_irq_ops = {
+	.map	= stmfx_irq_map,
+	.unmap	= stmfx_irq_unmap,
+};
+
+static void stmfx_irq_exit(struct i2c_client *client)
+{
+	struct stmfx *stmfx = i2c_get_clientdata(client);
+	int hwirq;
+
+	for (hwirq = 0; hwirq < STMFX_REG_IRQ_SRC_MAX; hwirq++)
+		irq_dispose_mapping(irq_find_mapping(stmfx->irq_domain, hwirq));
+
+	irq_domain_remove(stmfx->irq_domain);
+}
+
+static int stmfx_irq_init(struct i2c_client *client)
+{
+	struct stmfx *stmfx = i2c_get_clientdata(client);
+	u32 irqoutpin = 0, irqtrigger;
+	int ret;
+
+	stmfx->irq_domain = irq_domain_create_simple(dev_fwnode(stmfx->dev), STMFX_REG_IRQ_SRC_MAX,
+						     0, &stmfx_irq_ops, stmfx);
+	if (!stmfx->irq_domain) {
+		dev_err(stmfx->dev, "Failed to create IRQ domain\n");
+		return -EINVAL;
+	}
+
+	if (!of_property_read_bool(stmfx->dev->of_node, "drive-open-drain"))
+		irqoutpin |= STMFX_REG_IRQ_OUT_PIN_TYPE;
+
+	irqtrigger = irq_get_trigger_type(client->irq);
+	if ((irqtrigger & IRQ_TYPE_EDGE_RISING) ||
+	    (irqtrigger & IRQ_TYPE_LEVEL_HIGH))
+		irqoutpin |= STMFX_REG_IRQ_OUT_PIN_POL;
+
+	ret = regmap_write(stmfx->map, STMFX_REG_IRQ_OUT_PIN, irqoutpin);
+	if (ret)
+		goto irq_exit;
+
+	ret = devm_request_threaded_irq(stmfx->dev, client->irq,
+					NULL, stmfx_irq_handler,
+					irqtrigger | IRQF_ONESHOT,
+					"stmfx", stmfx);
+	if (ret)
+		goto irq_exit;
+
+	stmfx->irq = client->irq;
+
+	return 0;
+
+irq_exit:
+	stmfx_irq_exit(client);
+
+	return ret;
+}
+
+static int stmfx_chip_reset(struct stmfx *stmfx)
+{
+	int ret;
+
+	ret = regmap_write(stmfx->map, STMFX_REG_SYS_CTRL,
+			   STMFX_REG_SYS_CTRL_SWRST);
+	if (ret)
+		return ret;
+
+	msleep(STMFX_BOOT_TIME_MS);
+
+	return ret;
+}
+
+static int stmfx_chip_init(struct i2c_client *client)
+{
+	struct stmfx *stmfx = i2c_get_clientdata(client);
+	u32 id;
+	u8 version[2];
+	int ret;
+
+	stmfx->vdd = devm_regulator_get_optional(&client->dev, "vdd");
+	ret = PTR_ERR_OR_ZERO(stmfx->vdd);
+	if (ret) {
+		stmfx->vdd = NULL;
+		if (ret != -ENODEV)
+			return dev_err_probe(&client->dev, ret, "Failed to get VDD regulator\n");
+	}
+
+	if (stmfx->vdd) {
+		ret = regulator_enable(stmfx->vdd);
+		if (ret) {
+			dev_err(&client->dev, "VDD enable failed: %d\n", ret);
+			return ret;
+		}
+	}
+
+	ret = regmap_read(stmfx->map, STMFX_REG_CHIP_ID, &id);
+	if (ret) {
+		dev_err(&client->dev, "Error reading chip ID: %d\n", ret);
+		goto err;
+	}
+
+	/*
+	 * Check that ID is the complement of the I2C address:
+	 * STMFX I2C address follows the 7-bit format (MSB), that's why
+	 * client->addr is shifted.
+	 *
+	 * STMFX_I2C_ADDR|       STMFX         |        Linux
+	 *   input pin   | I2C device address  | I2C device address
+	 *---------------------------------------------------------
+	 *       0       | b: 1000 010x h:0x84 |       0x42
+	 *       1       | b: 1000 011x h:0x86 |       0x43
+	 */
+	if (FIELD_GET(STMFX_REG_CHIP_ID_MASK, ~id) != (client->addr << 1)) {
+		dev_err(&client->dev, "Unknown chip ID: %#x\n", id);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	ret = regmap_bulk_read(stmfx->map, STMFX_REG_FW_VERSION_MSB,
+			       version, ARRAY_SIZE(version));
+	if (ret) {
+		dev_err(&client->dev, "Error reading FW version: %d\n", ret);
+		goto err;
+	}
+
+	dev_info(&client->dev, "STMFX id: %#x, fw version: %x.%02x\n",
+		 id, version[0], version[1]);
+
+	ret = stmfx_chip_reset(stmfx);
+	if (ret) {
+		dev_err(&client->dev, "Failed to reset chip: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	if (stmfx->vdd)
+		regulator_disable(stmfx->vdd);
+
+	return ret;
+}
+
+static void stmfx_chip_exit(struct i2c_client *client)
+{
+	struct stmfx *stmfx = i2c_get_clientdata(client);
+
+	regmap_write(stmfx->map, STMFX_REG_IRQ_SRC_EN, 0);
+	regmap_write(stmfx->map, STMFX_REG_SYS_CTRL, 0);
+
+	if (stmfx->vdd) {
+		int ret;
+
+		ret = regulator_disable(stmfx->vdd);
+		if (ret)
+			dev_err(&client->dev,
+				"Failed to disable vdd regulator: %pe\n",
+				ERR_PTR(ret));
+	}
+}
+
+static int stmfx_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct stmfx *stmfx;
+	int ret;
+
+	stmfx = devm_kzalloc(dev, sizeof(*stmfx), GFP_KERNEL);
+	if (!stmfx)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, stmfx);
+
+	stmfx->dev = dev;
+
+	stmfx->map = devm_regmap_init_i2c(client, &stmfx_regmap_config);
+	if (IS_ERR(stmfx->map)) {
+		ret = PTR_ERR(stmfx->map);
+		dev_err(dev, "Failed to allocate register map: %d\n", ret);
+		return ret;
+	}
+
+	mutex_init(&stmfx->lock);
+
+	ret = stmfx_chip_init(client);
+	if (ret) {
+		if (ret == -ETIMEDOUT)
+			return -EPROBE_DEFER;
+		return ret;
+	}
+
+	if (client->irq < 0) {
+		dev_err(dev, "Failed to get IRQ: %d\n", client->irq);
+		ret = client->irq;
+		goto err_chip_exit;
+	}
+
+	ret = stmfx_irq_init(client);
+	if (ret)
+		goto err_chip_exit;
+
+	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				   stmfx_cells, ARRAY_SIZE(stmfx_cells), NULL,
+				   0, stmfx->irq_domain);
+	if (ret)
+		goto err_irq_exit;
+
+	return 0;
+
+err_irq_exit:
+	stmfx_irq_exit(client);
+err_chip_exit:
+	stmfx_chip_exit(client);
+
+	return ret;
+}
+
+static void stmfx_remove(struct i2c_client *client)
+{
+	stmfx_irq_exit(client);
+
+	stmfx_chip_exit(client);
+}
+
+static int stmfx_suspend(struct device *dev)
+{
+	struct stmfx *stmfx = dev_get_drvdata(dev);
+	int ret;
+
+	ret = regmap_raw_read(stmfx->map, STMFX_REG_SYS_CTRL,
+			      &stmfx->bkp_sysctrl, sizeof(stmfx->bkp_sysctrl));
+	if (ret)
+		return ret;
+
+	ret = regmap_raw_read(stmfx->map, STMFX_REG_IRQ_OUT_PIN,
+			      &stmfx->bkp_irqoutpin,
+			      sizeof(stmfx->bkp_irqoutpin));
+	if (ret)
+		return ret;
+
+	disable_irq(stmfx->irq);
+
+	if (stmfx->vdd)
+		return regulator_disable(stmfx->vdd);
+
+	return 0;
+}
+
+static int stmfx_resume(struct device *dev)
+{
+	struct stmfx *stmfx = dev_get_drvdata(dev);
+	int ret;
+
+	if (stmfx->vdd) {
+		ret = regulator_enable(stmfx->vdd);
+		if (ret) {
+			dev_err(stmfx->dev,
+				"VDD enable failed: %d\n", ret);
+			return ret;
+		}
+	}
+
+	/* Reset STMFX - supply has been stopped during suspend */
+	ret = stmfx_chip_reset(stmfx);
+	if (ret) {
+		dev_err(stmfx->dev, "Failed to reset chip: %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_raw_write(stmfx->map, STMFX_REG_SYS_CTRL,
+			       &stmfx->bkp_sysctrl, sizeof(stmfx->bkp_sysctrl));
+	if (ret)
+		return ret;
+
+	ret = regmap_raw_write(stmfx->map, STMFX_REG_IRQ_OUT_PIN,
+			       &stmfx->bkp_irqoutpin,
+			       sizeof(stmfx->bkp_irqoutpin));
+	if (ret)
+		return ret;
+
+	ret = regmap_raw_write(stmfx->map, STMFX_REG_IRQ_SRC_EN,
+			       &stmfx->irq_src, sizeof(stmfx->irq_src));
+	if (ret)
+		return ret;
+
+	enable_irq(stmfx->irq);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(stmfx_dev_pm_ops, stmfx_suspend, stmfx_resume);
+
+static const struct of_device_id stmfx_of_match[] = {
+	{ .compatible = "st,stmfx-0300", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stmfx_of_match);
+
+static struct i2c_driver stmfx_driver = {
+	.driver = {
+		.name = "stmfx-core",
+		.of_match_table = stmfx_of_match,
+		.pm = pm_sleep_ptr(&stmfx_dev_pm_ops),
+	},
+	.probe = stmfx_probe,
+	.remove = stmfx_remove,
+};
+module_i2c_driver(stmfx_driver);
+
+MODULE_DESCRIPTION("STMFX core driver");
+MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
+MODULE_LICENSE("GPL v2");