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, 495 insertions, 0 deletions

diff --git a/drivers/extcon/extcon-lc824206xa.c b/drivers/extcon/extcon-lc824206xa.c
new file mode 100644
index 000000000..56938748a
--- /dev/null
+++ b/drivers/extcon/extcon-lc824206xa.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ON Semiconductor LC824206XA Micro USB Switch driver
+ *
+ * Copyright (c) 2024 Hans de Goede <hansg@kernel.org>
+ *
+ * ON Semiconductor has an "Advance Information" datasheet available
+ * (ENA2222-D.PDF), but no full datasheet. So there is no documentation
+ * available for the registers.
+ *
+ * This driver is based on the register info from the extcon-fsa9285.c driver,
+ * from the Lollipop Android sources for the Lenovo Yoga Tablet 2 (Pro)
+ * 830 / 1050 / 1380 models. Note despite the name this is actually a driver
+ * for the LC824206XA not the FSA9285. The Android sources can be downloaded
+ * from Lenovo's support page for these tablets, filename:
+ * yoga_tab_2_osc_android_to_lollipop_201505.rar.
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/extcon-provider.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/power_supply.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/workqueue.h>
+
+/*
+ * Register defines as mentioned above there is no datasheet with register
+ * info, so this may not be 100% accurate.
+ */
+#define REG00				0x00
+#define REG00_INIT_VALUE		0x01
+
+#define REG_STATUS			0x01
+#define STATUS_OVP			BIT(0)
+#define STATUS_DATA_SHORT		BIT(1)
+#define STATUS_VBUS_PRESENT		BIT(2)
+#define STATUS_USB_ID			GENMASK(7, 3)
+#define STATUS_USB_ID_GND		0x80
+#define STATUS_USB_ID_ACA		0xf0
+#define STATUS_USB_ID_FLOAT		0xf8
+
+/*
+ * This controls the DP/DM muxes + other switches,
+ * meaning of individual bits is unknown.
+ */
+#define REG_SWITCH_CONTROL		0x02
+#define SWITCH_STEREO_MIC		0xc8
+#define SWITCH_USB_HOST			0xec
+#define SWITCH_DISCONNECTED		0xf8
+#define SWITCH_USB_DEVICE		0xfc
+
+/* 5 bits? ADC 0x10 GND, 0x1a-0x1f ACA, 0x1f float */
+#define REG_ID_PIN_ADC_VALUE		0x03
+
+/* Masks for all 3 interrupt registers */
+#define INTR_ID_PIN_CHANGE		BIT(0)
+#define INTR_VBUS_CHANGE		BIT(1)
+/* Both of these get set after a continuous mode ADC conversion */
+#define INTR_ID_PIN_ADC_INT1		BIT(2)
+#define INTR_ID_PIN_ADC_INT2		BIT(3)
+/* Charger type available in reg 0x09 */
+#define INTR_CHARGER_DET_DONE		BIT(4)
+#define INTR_OVP			BIT(5)
+
+/* There are 7 interrupt sources, bit 6 use is unknown (OCP?) */
+#define INTR_ALL			GENMASK(6, 0)
+
+/* Unmask interrupts this driver cares about */
+#define INTR_MASK \
+	(INTR_ALL & ~(INTR_ID_PIN_CHANGE | INTR_VBUS_CHANGE | INTR_CHARGER_DET_DONE))
+
+/* Active (event happened and not cleared yet) interrupts */
+#define REG_INTR_STATUS			0x04
+
+/*
+ * Writing a 1 to a bit here clears it in INTR_STATUS. These bits do NOT
+ * auto-reset to 0, so these must be set to 0 manually after clearing.
+ */
+#define REG_INTR_CLEAR			0x05
+
+/* Interrupts which bit is set to 1 here will not raise the HW IRQ */
+#define REG_INTR_MASK			0x06
+
+/* ID pin ADC control, meaning of individual bits is unknown */
+#define REG_ID_PIN_ADC_CTRL		0x07
+#define ID_PIN_ADC_AUTO			0x40
+#define ID_PIN_ADC_CONTINUOUS		0x44
+
+#define REG_CHARGER_DET			0x08
+#define CHARGER_DET_ON			BIT(0)
+#define CHARGER_DET_CDP_ON		BIT(1)
+#define CHARGER_DET_CDP_VAL		BIT(2)
+
+#define REG_CHARGER_TYPE		0x09
+#define CHARGER_TYPE_UNKNOWN		0x00
+#define CHARGER_TYPE_DCP		0x01
+#define CHARGER_TYPE_SDP_OR_CDP		0x04
+#define CHARGER_TYPE_QC			0x06
+
+#define REG10				0x10
+#define REG10_INIT_VALUE		0x00
+
+struct lc824206xa_data {
+	struct work_struct work;
+	struct i2c_client *client;
+	struct extcon_dev *edev;
+	struct power_supply *psy;
+	struct regulator *vbus_boost;
+	unsigned int usb_type;
+	unsigned int cable;
+	unsigned int previous_cable;
+	u8 switch_control;
+	u8 previous_switch_control;
+	bool vbus_ok;
+	bool vbus_boost_enabled;
+	bool fastcharge_over_miclr;
+};
+
+static const unsigned int lc824206xa_cables[] = {
+	EXTCON_USB_HOST,
+	EXTCON_CHG_USB_SDP,
+	EXTCON_CHG_USB_CDP,
+	EXTCON_CHG_USB_DCP,
+	EXTCON_CHG_USB_ACA,
+	EXTCON_CHG_USB_FAST,
+	EXTCON_NONE,
+};
+
+/* read/write reg helpers to add error logging to smbus byte functions */
+static int lc824206xa_read_reg(struct lc824206xa_data *data, u8 reg)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(data->client, reg);
+	if (ret < 0)
+		dev_err(&data->client->dev, "Error %d reading reg 0x%02x\n", ret, reg);
+
+	return ret;
+}
+
+static int lc824206xa_write_reg(struct lc824206xa_data *data, u8 reg, u8 val)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, reg, val);
+	if (ret < 0)
+		dev_err(&data->client->dev, "Error %d writing reg 0x%02x\n", ret, reg);
+
+	return ret;
+}
+
+static int lc824206xa_get_id(struct lc824206xa_data *data)
+{
+	int ret;
+
+	ret = lc824206xa_write_reg(data, REG_ID_PIN_ADC_CTRL, ID_PIN_ADC_CONTINUOUS);
+	if (ret)
+		return ret;
+
+	ret = lc824206xa_read_reg(data, REG_ID_PIN_ADC_VALUE);
+
+	lc824206xa_write_reg(data, REG_ID_PIN_ADC_CTRL, ID_PIN_ADC_AUTO);
+
+	return ret;
+}
+
+static void lc824206xa_set_vbus_boost(struct lc824206xa_data *data, bool enable)
+{
+	int ret;
+
+	if (data->vbus_boost_enabled == enable)
+		return;
+
+	if (enable)
+		ret = regulator_enable(data->vbus_boost);
+	else
+		ret = regulator_disable(data->vbus_boost);
+
+	if (ret == 0)
+		data->vbus_boost_enabled = enable;
+	else
+		dev_err(&data->client->dev, "Error updating Vbus boost regulator: %d\n", ret);
+}
+
+static void lc824206xa_charger_detect(struct lc824206xa_data *data)
+{
+	int charger_type, ret;
+
+	charger_type = lc824206xa_read_reg(data, REG_CHARGER_TYPE);
+	if (charger_type < 0)
+		return;
+
+	dev_dbg(&data->client->dev, "charger type 0x%02x\n", charger_type);
+
+	switch (charger_type) {
+	case CHARGER_TYPE_UNKNOWN:
+		data->usb_type = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+		/* Treat as SDP */
+		data->cable = EXTCON_CHG_USB_SDP;
+		data->switch_control = SWITCH_USB_DEVICE;
+		break;
+	case CHARGER_TYPE_SDP_OR_CDP:
+		data->usb_type = POWER_SUPPLY_USB_TYPE_SDP;
+		data->cable = EXTCON_CHG_USB_SDP;
+		data->switch_control = SWITCH_USB_DEVICE;
+
+		ret = lc824206xa_write_reg(data, REG_CHARGER_DET,
+					   CHARGER_DET_CDP_ON | CHARGER_DET_ON);
+		if (ret < 0)
+			break;
+
+		msleep(100);
+		ret = lc824206xa_read_reg(data, REG_CHARGER_DET);
+		if (ret >= 0 && (ret & CHARGER_DET_CDP_VAL)) {
+			data->usb_type = POWER_SUPPLY_USB_TYPE_CDP;
+			data->cable = EXTCON_CHG_USB_CDP;
+		}
+
+		lc824206xa_write_reg(data, REG_CHARGER_DET, CHARGER_DET_ON);
+		break;
+	case CHARGER_TYPE_DCP:
+		data->usb_type = POWER_SUPPLY_USB_TYPE_DCP;
+		data->cable = EXTCON_CHG_USB_DCP;
+		if (data->fastcharge_over_miclr)
+			data->switch_control = SWITCH_STEREO_MIC;
+		else
+			data->switch_control = SWITCH_DISCONNECTED;
+		break;
+	case CHARGER_TYPE_QC:
+		data->usb_type = POWER_SUPPLY_USB_TYPE_DCP;
+		data->cable = EXTCON_CHG_USB_DCP;
+		data->switch_control = SWITCH_DISCONNECTED;
+		break;
+	default:
+		dev_warn(&data->client->dev, "Unknown charger type: 0x%02x\n", charger_type);
+		break;
+	}
+}
+
+static void lc824206xa_work(struct work_struct *work)
+{
+	struct lc824206xa_data *data = container_of(work, struct lc824206xa_data, work);
+	bool vbus_boost_enable = false;
+	int status, id;
+
+	status = lc824206xa_read_reg(data, REG_STATUS);
+	if (status < 0)
+		return;
+
+	dev_dbg(&data->client->dev, "status 0x%02x\n", status);
+
+	data->vbus_ok = (status & (STATUS_VBUS_PRESENT | STATUS_OVP)) == STATUS_VBUS_PRESENT;
+
+	/* Read id pin ADC if necessary */
+	switch (status & STATUS_USB_ID) {
+	case STATUS_USB_ID_GND:
+	case STATUS_USB_ID_FLOAT:
+		break;
+	default:
+		/* Happens when the connector is inserted slowly, log at dbg level */
+		dev_dbg(&data->client->dev, "Unknown status 0x%02x\n", status);
+		fallthrough;
+	case STATUS_USB_ID_ACA:
+		id = lc824206xa_get_id(data);
+		dev_dbg(&data->client->dev, "RID 0x%02x\n", id);
+		switch (id) {
+		case 0x10:
+			status = STATUS_USB_ID_GND;
+			break;
+		case 0x18 ... 0x1e:
+			status = STATUS_USB_ID_ACA;
+			break;
+		case 0x1f:
+			status = STATUS_USB_ID_FLOAT;
+			break;
+		default:
+			dev_warn(&data->client->dev, "Unknown RID 0x%02x\n", id);
+			return;
+		}
+	}
+
+	/* Check for out of spec OTG charging hubs, treat as ACA */
+	if ((status & STATUS_USB_ID) == STATUS_USB_ID_GND &&
+	    data->vbus_ok && !data->vbus_boost_enabled) {
+		dev_info(&data->client->dev, "Out of spec USB host adapter with Vbus present, not enabling 5V output\n");
+		status = STATUS_USB_ID_ACA;
+	}
+
+	switch (status & STATUS_USB_ID) {
+	case STATUS_USB_ID_ACA:
+		data->usb_type = POWER_SUPPLY_USB_TYPE_ACA;
+		data->cable = EXTCON_CHG_USB_ACA;
+		data->switch_control = SWITCH_USB_HOST;
+		break;
+	case STATUS_USB_ID_GND:
+		data->usb_type = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+		data->cable = EXTCON_USB_HOST;
+		data->switch_control = SWITCH_USB_HOST;
+		vbus_boost_enable = true;
+		break;
+	case STATUS_USB_ID_FLOAT:
+		/* When fast charging with Vbus > 5V, OVP will be set */
+		if (data->fastcharge_over_miclr &&
+		    data->switch_control == SWITCH_STEREO_MIC &&
+		    (status & STATUS_OVP)) {
+			data->cable = EXTCON_CHG_USB_FAST;
+			break;
+		}
+
+		if (data->vbus_ok) {
+			lc824206xa_charger_detect(data);
+		} else {
+			data->usb_type = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+			data->cable = EXTCON_NONE;
+			data->switch_control = SWITCH_DISCONNECTED;
+		}
+		break;
+	}
+
+	lc824206xa_set_vbus_boost(data, vbus_boost_enable);
+
+	if (data->switch_control != data->previous_switch_control) {
+		lc824206xa_write_reg(data, REG_SWITCH_CONTROL, data->switch_control);
+		data->previous_switch_control = data->switch_control;
+	}
+
+	if (data->cable != data->previous_cable) {
+		extcon_set_state_sync(data->edev, data->previous_cable, false);
+		extcon_set_state_sync(data->edev, data->cable, true);
+		data->previous_cable = data->cable;
+	}
+
+	power_supply_changed(data->psy);
+}
+
+static irqreturn_t lc824206xa_irq(int irq, void *_data)
+{
+	struct lc824206xa_data *data = _data;
+	int intr_status;
+
+	intr_status = lc824206xa_read_reg(data, REG_INTR_STATUS);
+	if (intr_status < 0)
+		intr_status = INTR_ALL; /* Should never happen, clear all */
+
+	dev_dbg(&data->client->dev, "interrupt 0x%02x\n", intr_status);
+
+	lc824206xa_write_reg(data, REG_INTR_CLEAR, intr_status);
+	lc824206xa_write_reg(data, REG_INTR_CLEAR, 0);
+
+	schedule_work(&data->work);
+	return IRQ_HANDLED;
+}
+
+/*
+ * Newer charger (power_supply) drivers expect the max input current to be
+ * provided by a parent power_supply device for the charger chip.
+ */
+static int lc824206xa_psy_get_prop(struct power_supply *psy,
+				   enum power_supply_property psp,
+				   union power_supply_propval *val)
+{
+	struct lc824206xa_data *data = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = data->vbus_ok && !data->vbus_boost_enabled;
+		break;
+	case POWER_SUPPLY_PROP_USB_TYPE:
+		val->intval = data->usb_type;
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_MAX:
+		switch (data->usb_type) {
+		case POWER_SUPPLY_USB_TYPE_DCP:
+		case POWER_SUPPLY_USB_TYPE_ACA:
+			val->intval = 2000000;
+			break;
+		case POWER_SUPPLY_USB_TYPE_CDP:
+			val->intval = 1500000;
+			break;
+		default:
+			val->intval = 500000;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const enum power_supply_property lc824206xa_psy_props[] = {
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_USB_TYPE,
+	POWER_SUPPLY_PROP_CURRENT_MAX,
+};
+
+static const struct power_supply_desc lc824206xa_psy_desc = {
+	.name = "lc824206xa-charger-detect",
+	.type = POWER_SUPPLY_TYPE_USB,
+	.usb_types = BIT(POWER_SUPPLY_USB_TYPE_SDP) |
+		     BIT(POWER_SUPPLY_USB_TYPE_CDP) |
+		     BIT(POWER_SUPPLY_USB_TYPE_DCP) |
+		     BIT(POWER_SUPPLY_USB_TYPE_ACA) |
+		     BIT(POWER_SUPPLY_USB_TYPE_UNKNOWN),
+	.properties = lc824206xa_psy_props,
+	.num_properties = ARRAY_SIZE(lc824206xa_psy_props),
+	.get_property = lc824206xa_psy_get_prop,
+};
+
+static int lc824206xa_probe(struct i2c_client *client)
+{
+	struct power_supply_config psy_cfg = { };
+	struct device *dev = &client->dev;
+	struct lc824206xa_data *data;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	INIT_WORK(&data->work, lc824206xa_work);
+	data->cable = EXTCON_NONE;
+	data->previous_cable = EXTCON_NONE;
+	data->usb_type = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+	/* Some designs use a custom fast-charge protocol over the mic L/R inputs */
+	data->fastcharge_over_miclr =
+		device_property_read_bool(dev, "onnn,enable-miclr-for-dcp");
+
+	data->vbus_boost = devm_regulator_get(dev, "vbus");
+	if (IS_ERR(data->vbus_boost))
+		return dev_err_probe(dev, PTR_ERR(data->vbus_boost),
+				     "getting regulator\n");
+
+	/* Init */
+	ret = lc824206xa_write_reg(data, REG00, REG00_INIT_VALUE);
+	ret |= lc824206xa_write_reg(data, REG10, REG10_INIT_VALUE);
+	msleep(100);
+	ret |= lc824206xa_write_reg(data, REG_INTR_CLEAR, INTR_ALL);
+	ret |= lc824206xa_write_reg(data, REG_INTR_CLEAR, 0);
+	ret |= lc824206xa_write_reg(data, REG_INTR_MASK, INTR_MASK);
+	ret |= lc824206xa_write_reg(data, REG_ID_PIN_ADC_CTRL, ID_PIN_ADC_AUTO);
+	ret |= lc824206xa_write_reg(data, REG_CHARGER_DET, CHARGER_DET_ON);
+	if (ret)
+		return -EIO;
+
+	/* Initialize extcon device */
+	data->edev = devm_extcon_dev_allocate(dev, lc824206xa_cables);
+	if (IS_ERR(data->edev))
+		return PTR_ERR(data->edev);
+
+	ret = devm_extcon_dev_register(dev, data->edev);
+	if (ret)
+		return dev_err_probe(dev, ret, "registering extcon device\n");
+
+	psy_cfg.drv_data = data;
+	data->psy = devm_power_supply_register(dev, &lc824206xa_psy_desc, &psy_cfg);
+	if (IS_ERR(data->psy))
+		return dev_err_probe(dev, PTR_ERR(data->psy), "registering power supply\n");
+
+	ret = devm_request_threaded_irq(dev, client->irq, NULL, lc824206xa_irq,
+					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					KBUILD_MODNAME, data);
+	if (ret)
+		return dev_err_probe(dev, ret, "requesting IRQ\n");
+
+	/* Sync initial state */
+	schedule_work(&data->work);
+	return 0;
+}
+
+static const struct i2c_device_id lc824206xa_i2c_ids[] = {
+	{ "lc824206xa" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, lc824206xa_i2c_ids);
+
+static struct i2c_driver lc824206xa_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+	},
+	.probe = lc824206xa_probe,
+	.id_table = lc824206xa_i2c_ids,
+};
+
+module_i2c_driver(lc824206xa_driver);
+
+MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
+MODULE_DESCRIPTION("LC824206XA Micro USB Switch driver");
+MODULE_LICENSE("GPL");