x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 466 insertions, 0 deletions

diff --git a/drivers/regulator/tps65185.c b/drivers/regulator/tps65185.c
new file mode 100644
index 000000000..6a3130177
--- /dev/null
+++ b/drivers/regulator/tps65185.c
@@ -0,0 +1,466 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (C) 2025 Andreas Kemnade
+
+/* Datasheet: https://www.ti.com/lit/gpn/tps65185 */
+
+#include <linux/cleanup.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/hwmon.h>
+#include <linux/pm_runtime.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regmap.h>
+
+#define TPS65185_REG_TMST_VALUE 0
+#define TPS65185_REG_ENABLE 1
+#define TPS65185_REG_VADJ 2
+#define TPS65185_REG_VCOM1 3
+#define TPS65185_REG_VCOM2 4
+#define TPS65185_REG_INT_EN1 5
+#define TPS65185_REG_INT_EN2 6
+#define TPS65185_REG_INT1 7
+#define TPS65185_REG_INT2 8
+#define TPS65185_REG_TMST1 0xd
+#define TPS65185_REG_TMST2 0xe
+#define TPS65185_REG_PG 0xf
+#define TPS65185_REG_REVID 0x10
+
+#define TPS65185_READ_THERM BIT(7)
+#define TPS65185_CONV_END BIT(5)
+
+#define TPS65185_ENABLE_ACTIVE BIT(7)
+#define TPS65185_ENABLE_STANDBY BIT(6)
+
+#define PGOOD_TIMEOUT_MSECS 200
+
+struct tps65185_data {
+	struct device *dev;
+	struct regmap *regmap;
+	struct gpio_desc *pgood_gpio;
+	struct gpio_desc *pwrup_gpio;
+	struct gpio_desc *vcom_ctrl_gpio;
+	struct gpio_desc *wakeup_gpio;
+	struct completion pgood_completion;
+	int pgood_irq;
+	struct completion tmst_completion;
+};
+
+static const struct hwmon_channel_info *tps65185_info[] = {
+	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+	NULL
+};
+
+static int tps65185_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			       u32 attr, int channel, long *temp)
+{
+	struct tps65185_data *data = dev_get_drvdata(dev);
+	unsigned int val;
+	int ret;
+
+	reinit_completion(&data->tmst_completion);
+	/* start acquisition */
+	regmap_update_bits(data->regmap, TPS65185_REG_TMST1,
+			   TPS65185_READ_THERM, TPS65185_READ_THERM);
+	wait_for_completion_timeout(&data->tmst_completion,
+				    msecs_to_jiffies(PGOOD_TIMEOUT_MSECS));
+	ret = regmap_read(data->regmap, TPS65185_REG_TMST1, &val);
+	if (!(val & TPS65185_CONV_END))
+		return -ETIMEDOUT;
+
+	ret = regmap_read(data->regmap, TPS65185_REG_TMST_VALUE, &val);
+	if (ret)
+		return ret;
+
+	*temp = (s8)val * 1000;
+
+	return 0;
+}
+
+static umode_t tps65185_hwmon_is_visible(const void *data,
+					 enum hwmon_sensor_types type,
+					 u32 attr, int channel)
+{
+	return 0444;
+}
+
+static const struct hwmon_ops tps65185_hwmon_ops = {
+	.is_visible = tps65185_hwmon_is_visible,
+	.read = tps65185_hwmon_read,
+};
+
+static const struct hwmon_chip_info tps65185_chip_info = {
+	.ops = &tps65185_hwmon_ops,
+	.info = tps65185_info,
+};
+
+static bool tps65185_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case TPS65185_REG_TMST_VALUE:
+	case TPS65185_REG_ENABLE:
+	case TPS65185_REG_VCOM2:
+	case TPS65185_REG_INT1:
+	case TPS65185_REG_INT2:
+	case TPS65185_REG_TMST1:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x10,
+	.cache_type = REGCACHE_MAPLE,
+	.volatile_reg = tps65185_volatile_reg,
+};
+
+static const struct regulator_ops tps65185_v3p3ops = {
+	.list_voltage = regulator_list_voltage_linear,
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+};
+
+static int tps65185_check_powergood(struct regulator_dev *rdev)
+{
+	struct tps65185_data *data = rdev_get_drvdata(rdev);
+
+	return gpiod_get_value_cansleep(data->pgood_gpio);
+}
+
+static int tps65185_vposneg_get_voltage_sel(struct regulator_dev *rdev)
+{
+	int ret;
+
+	ret = regulator_get_voltage_sel_regmap(rdev);
+	if (ret < 0)
+		return ret;
+
+	/* highest value is lowest voltage */
+	return 6 - ret;
+}
+
+static int tps65185_vposneg_set_voltage_sel(struct regulator_dev *rdev, unsigned int selector)
+{
+	return regulator_set_voltage_sel_regmap(rdev, 6 - selector);
+}
+
+static irqreturn_t pgood_handler(int irq, void *dev_id)
+{
+	struct tps65185_data *data = dev_id;
+
+	complete(&data->pgood_completion);
+
+	return IRQ_HANDLED;
+}
+
+static int tps65185_vposneg_enable(struct regulator_dev *rdev)
+{
+	struct tps65185_data *data = rdev_get_drvdata(rdev);
+	int ret;
+
+	reinit_completion(&data->pgood_completion);
+	if (data->pwrup_gpio)
+		ret = gpiod_set_value_cansleep(data->pwrup_gpio, 1);
+	else
+		ret = regmap_update_bits(data->regmap, TPS65185_REG_ENABLE,
+					 TPS65185_ENABLE_ACTIVE,
+					 TPS65185_ENABLE_ACTIVE);
+
+	if (ret)
+		return ret;
+
+	dev_dbg(data->dev, "turning on...");
+	wait_for_completion_timeout(&data->pgood_completion,
+				    msecs_to_jiffies(PGOOD_TIMEOUT_MSECS));
+	dev_dbg(data->dev, "turned on");
+	ret = gpiod_get_value_cansleep(data->pgood_gpio);
+	if (ret < 0)
+		return ret;
+	if (!ret)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int tps65185_vposneg_disable(struct regulator_dev *rdev)
+{
+	struct tps65185_data *data = rdev_get_drvdata(rdev);
+	int ret;
+
+	if (data->pwrup_gpio)
+		ret = gpiod_set_value_cansleep(data->pwrup_gpio, 0);
+	else
+		ret = regmap_update_bits(data->regmap, TPS65185_REG_ENABLE,
+					 TPS65185_ENABLE_STANDBY,
+					 TPS65185_ENABLE_STANDBY);
+
+	return ret;
+}
+
+static int tps65185_vcom_set_voltage_sel(struct regulator_dev *rdev, unsigned int selector)
+{
+	struct tps65185_data *data = rdev_get_drvdata(rdev);
+	int ret;
+
+	ret = regmap_update_bits(data->regmap, TPS65185_REG_VCOM2, BIT(0), selector >> 8);
+	if (ret < 0)
+		return ret;
+
+	return regmap_write(data->regmap, TPS65185_REG_VCOM1, selector & 0xFF);
+}
+
+static int tps65185_vcom_get_voltage_sel(struct regulator_dev *rdev)
+{
+	struct tps65185_data *data = rdev_get_drvdata(rdev);
+	int ret;
+	unsigned int sel, sel2;
+
+	ret = regmap_read(data->regmap, TPS65185_REG_VCOM1, &sel);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(data->regmap, TPS65185_REG_VCOM2, &sel2);
+	if (ret < 0)
+		return ret;
+
+	if (sel2 & BIT(0))
+		sel |= 0x100;
+
+	return sel;
+}
+
+static const struct regulator_ops tps65185_vcom_ops = {
+	.list_voltage = regulator_list_voltage_linear,
+	.map_voltage = regulator_map_voltage_linear,
+	.set_voltage_sel = tps65185_vcom_set_voltage_sel,
+	.get_voltage_sel = tps65185_vcom_get_voltage_sel,
+};
+
+static const struct regulator_ops tps65185_vposneg_ops = {
+	.list_voltage = regulator_list_voltage_linear,
+	.map_voltage = regulator_map_voltage_linear,
+	.enable = tps65185_vposneg_enable,
+	.disable = tps65185_vposneg_disable,
+	.is_enabled = tps65185_check_powergood,
+	.set_voltage_sel = tps65185_vposneg_set_voltage_sel,
+	.get_voltage_sel = tps65185_vposneg_get_voltage_sel,
+};
+
+static const struct regulator_desc regulators[] = {
+	{
+		.name = "v3p3",
+		.of_match = of_match_ptr("v3p3"),
+		.regulators_node = of_match_ptr("regulators"),
+		.id = 0,
+		.ops = &tps65185_v3p3ops,
+		.type = REGULATOR_VOLTAGE,
+		.owner = THIS_MODULE,
+		.enable_reg = TPS65185_REG_ENABLE,
+		.enable_mask = BIT(5),
+		.n_voltages = 1,
+		.min_uV = 3300000,
+	},
+	{
+		.name = "vposneg",
+		.of_match = of_match_ptr("vposneg"),
+		.regulators_node = of_match_ptr("regulators"),
+		.id = 1,
+		.ops = &tps65185_vposneg_ops,
+		.type = REGULATOR_VOLTAGE,
+		.owner = THIS_MODULE,
+		.n_voltages = 4,
+		.vsel_reg = TPS65185_REG_VADJ,
+		.vsel_mask = 0x7,
+		.min_uV = 14250000,
+		.uV_step = 250000,
+	}
+};
+
+static const struct regulator_desc vcom_regulator_desc = {
+	.name = "vcom",
+	.of_match = of_match_ptr("vcom"),
+	.regulators_node = of_match_ptr("regulators"),
+	.supply_name = "vposneg",
+	.id = 2,
+	.ops = &tps65185_vcom_ops,
+	.type = REGULATOR_VOLTAGE,
+	.owner = THIS_MODULE,
+	.n_voltages = 511,
+	.min_uV = 0,
+	.uV_step = 10000,
+};
+
+static irqreturn_t tps65185_irq_thread(int irq, void *dev_id)
+{
+	struct tps65185_data *data = dev_id;
+	unsigned int int_status_1, int_status_2;
+	int ret;
+
+	/* read both status to have irq cleared */
+	ret = regmap_read(data->regmap, TPS65185_REG_INT1, &int_status_1);
+	if (ret)
+		return IRQ_NONE;
+
+	ret = regmap_read(data->regmap, TPS65185_REG_INT2, &int_status_2);
+	if (ret)
+		return IRQ_NONE;
+
+	if (int_status_2 & BIT(0))
+		complete(&data->tmst_completion);
+
+	dev_dbg(data->dev, "irq status %02x %02x\n", int_status_1, int_status_2);
+
+	if (int_status_1 || int_status_2)
+		return IRQ_HANDLED;
+
+	return IRQ_NONE;
+}
+
+static int tps65185_probe(struct i2c_client *client)
+{
+	struct tps65185_data *data;
+	struct regulator_config config = { };
+	struct regulator_dev *rdev;
+	int ret = 0;
+	int i;
+
+	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->regmap = devm_regmap_init_i2c(client, &regmap_config);
+	if (IS_ERR(data->regmap))
+		return dev_err_probe(&client->dev, PTR_ERR(data->regmap),
+				     "failed to allocate regmap!\n");
+
+	data->pgood_gpio = devm_gpiod_get(&client->dev, "pwr-good", GPIOD_IN);
+	if (IS_ERR(data->pgood_gpio))
+		return dev_err_probe(&client->dev,
+				     PTR_ERR(data->pgood_gpio),
+				     "failed to get power good gpio\n");
+
+	data->pgood_irq = gpiod_to_irq(data->pgood_gpio);
+	if (data->pgood_irq < 0)
+		return data->pgood_irq;
+
+	data->pwrup_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(data->pwrup_gpio))
+		return dev_err_probe(&client->dev, PTR_ERR(data->pwrup_gpio),
+				     "failed to get pwrup gpio\n");
+
+	data->wakeup_gpio = devm_gpiod_get_optional(&client->dev, "wakeup", GPIOD_OUT_HIGH);
+	if (IS_ERR(data->wakeup_gpio))
+		return dev_err_probe(&client->dev,
+				     PTR_ERR(data->wakeup_gpio),
+				     "failed to get wakeup gpio\n");
+
+	data->vcom_ctrl_gpio = devm_gpiod_get_optional(&client->dev, "vcom-ctrl", GPIOD_OUT_LOW);
+	if (IS_ERR(data->vcom_ctrl_gpio))
+		return dev_err_probe(&client->dev,
+				     PTR_ERR(data->vcom_ctrl_gpio),
+				     "failed to get vcm ctrl gpio\n");
+
+	ret = devm_regulator_get_enable(&client->dev, "vin");
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to get vin regulator\n");
+
+	// TPS65185x PMIC for E Ink Vizplex Enabled Electronic Paper Display Chapter 7.6 Figure 2:
+	// "Minimum delay time between WAKEUP rising edge and IC ready to accept I2C transaction."
+	// https://www.ti.com/lit/ds/symlink/tps65185.pdf
+	usleep_range(1800, 3000);
+
+	data->dev = &client->dev;
+	i2c_set_clientdata(client, data);
+
+	init_completion(&data->pgood_completion);
+	init_completion(&data->tmst_completion);
+
+	ret = devm_request_threaded_irq(&client->dev, data->pgood_irq, NULL,
+					pgood_handler,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					"PGOOD", data);
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to request power good irq\n");
+
+	if (client->irq) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						NULL, tps65185_irq_thread,
+						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+						"tps65185", data);
+		if (ret)
+			return dev_err_probe(&client->dev, ret,
+					     "failed to request irq\n");
+	}
+
+	ret = regmap_update_bits(data->regmap, TPS65185_REG_INT_EN2, BIT(0), BIT(0));
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to enable temp irq\n");
+
+	config.driver_data = data;
+	config.dev = &client->dev;
+	config.regmap = data->regmap;
+
+	for (i = 0; i < ARRAY_SIZE(regulators); i++) {
+		rdev = devm_regulator_register(&client->dev, &regulators[i],
+					       &config);
+		if (IS_ERR(rdev))
+			return dev_err_probe(&client->dev, PTR_ERR(rdev),
+					     "failed to register %s regulator\n",
+					     regulators[i].name);
+	}
+
+	config.ena_gpiod = data->vcom_ctrl_gpio;
+	rdev = devm_regulator_register(&client->dev, &vcom_regulator_desc, &config);
+	if (IS_ERR(rdev))
+		return dev_err_probe(&client->dev, PTR_ERR(rdev),
+				     "failed to register vcom regulator\n");
+
+	if (IS_REACHABLE(CONFIG_HWMON)) {
+		struct device *hwmon_dev;
+
+		hwmon_dev = devm_hwmon_device_register_with_info(&client->dev, "tps65185", data,
+								 &tps65185_chip_info, NULL);
+		if (IS_ERR(hwmon_dev))
+			dev_notice(&client->dev, "failed to register hwmon\n");
+	}
+
+	return 0;
+}
+
+static const struct of_device_id tps65185_dt_ids[] = {
+	{
+		.compatible = "ti,tps65185",
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, tps65185_dt_ids);
+
+static struct i2c_driver tps65185_i2c_driver = {
+	.driver = {
+		   .name = "tps65185",
+		   .of_match_table = tps65185_dt_ids,
+	},
+	.probe = tps65185_probe,
+};
+
+module_i2c_driver(tps65185_i2c_driver);
+
+/* Module information */
+MODULE_DESCRIPTION("TPS65185 regulator driver");
+MODULE_LICENSE("GPL");
+