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, 443 insertions, 0 deletions

diff --git a/drivers/input/misc/max77693-haptic.c b/drivers/input/misc/max77693-haptic.c
new file mode 100644
index 000000000..5d45680d7
--- /dev/null
+++ b/drivers/input/misc/max77693-haptic.c
@@ -0,0 +1,443 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MAXIM MAX77693/MAX77843 Haptic device driver
+ *
+ * Copyright (C) 2014,2015 Samsung Electronics
+ * Jaewon Kim <jaewon02.kim@samsung.com>
+ * Krzysztof Kozlowski <krzk@kernel.org>
+ *
+ * This program is not provided / owned by Maxim Integrated Products.
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/string_choices.h>
+#include <linux/workqueue.h>
+#include <linux/regulator/consumer.h>
+#include <linux/mfd/max77693.h>
+#include <linux/mfd/max77693-common.h>
+#include <linux/mfd/max77693-private.h>
+#include <linux/mfd/max77705-private.h>
+#include <linux/mfd/max77843-private.h>
+
+#define MAX_MAGNITUDE_SHIFT	16
+
+enum max77693_haptic_motor_type {
+	MAX77693_HAPTIC_ERM = 0,
+	MAX77693_HAPTIC_LRA,
+};
+
+enum max77693_haptic_pulse_mode {
+	MAX77693_HAPTIC_EXTERNAL_MODE = 0,
+	MAX77693_HAPTIC_INTERNAL_MODE,
+};
+
+enum max77693_haptic_pwm_divisor {
+	MAX77693_HAPTIC_PWM_DIVISOR_32 = 0,
+	MAX77693_HAPTIC_PWM_DIVISOR_64,
+	MAX77693_HAPTIC_PWM_DIVISOR_128,
+	MAX77693_HAPTIC_PWM_DIVISOR_256,
+};
+
+struct max77693_haptic {
+	enum max77693_types dev_type;
+
+	struct regmap *regmap_pmic;
+	struct regmap *regmap_haptic;
+	struct device *dev;
+	struct input_dev *input_dev;
+	struct pwm_device *pwm_dev;
+	struct regulator *motor_reg;
+
+	bool enabled;
+	bool suspend_state;
+	unsigned int magnitude;
+	unsigned int pwm_duty;
+	enum max77693_haptic_motor_type type;
+	enum max77693_haptic_pulse_mode mode;
+
+	struct work_struct work;
+};
+
+static int max77693_haptic_set_duty_cycle(struct max77693_haptic *haptic)
+{
+	struct pwm_state state;
+	int error;
+
+	pwm_init_state(haptic->pwm_dev, &state);
+	state.duty_cycle = (state.period + haptic->pwm_duty) / 2;
+
+	error = pwm_apply_might_sleep(haptic->pwm_dev, &state);
+	if (error) {
+		dev_err(haptic->dev,
+			"failed to set pwm duty cycle: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int max77843_haptic_bias(struct max77693_haptic *haptic, bool on)
+{
+	int error;
+
+	if (haptic->dev_type != TYPE_MAX77843)
+		return 0;
+
+	error = regmap_update_bits(haptic->regmap_haptic,
+				   MAX77843_SYS_REG_MAINCTRL1,
+				   MAX77843_MAINCTRL1_BIASEN_MASK,
+				   on << MAINCTRL1_BIASEN_SHIFT);
+	if (error) {
+		dev_err(haptic->dev, "failed to %s bias: %d\n",
+			str_enable_disable(on), error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int max77693_haptic_configure(struct max77693_haptic *haptic,
+				     bool enable)
+{
+	unsigned int value, config_reg;
+	int error;
+
+	switch (haptic->dev_type) {
+	case TYPE_MAX77693:
+		value = ((haptic->type << MAX77693_CONFIG2_MODE) |
+			(enable << MAX77693_CONFIG2_MEN) |
+			(haptic->mode << MAX77693_CONFIG2_HTYP) |
+			MAX77693_HAPTIC_PWM_DIVISOR_128);
+		config_reg = MAX77693_HAPTIC_REG_CONFIG2;
+		break;
+	case TYPE_MAX77705:
+		value = ((haptic->type << MAX77693_CONFIG2_MODE) |
+			(enable << MAX77693_CONFIG2_MEN) |
+			(haptic->mode << MAX77693_CONFIG2_HTYP) |
+			MAX77693_HAPTIC_PWM_DIVISOR_128);
+		config_reg = MAX77705_PMIC_REG_MCONFIG;
+		break;
+	case TYPE_MAX77843:
+		value = (haptic->type << MCONFIG_MODE_SHIFT) |
+			(enable << MCONFIG_MEN_SHIFT) |
+			MAX77693_HAPTIC_PWM_DIVISOR_128;
+		config_reg = MAX77843_HAP_REG_MCONFIG;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	error = regmap_write(haptic->regmap_haptic,
+			     config_reg, value);
+	if (error) {
+		dev_err(haptic->dev,
+			"failed to update haptic config: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int max77693_haptic_lowsys(struct max77693_haptic *haptic, bool enable)
+{
+	int error;
+
+	if (haptic->dev_type != TYPE_MAX77693)
+		return 0;
+
+	error = regmap_update_bits(haptic->regmap_pmic,
+				   MAX77693_PMIC_REG_LSCNFG,
+				   MAX77693_PMIC_LOW_SYS_MASK,
+				   enable << MAX77693_PMIC_LOW_SYS_SHIFT);
+	if (error) {
+		dev_err(haptic->dev, "cannot update pmic regmap: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static void max77693_haptic_enable(struct max77693_haptic *haptic)
+{
+	struct pwm_state state;
+	int error;
+
+	if (haptic->enabled)
+		return;
+
+	pwm_init_state(haptic->pwm_dev, &state);
+	state.duty_cycle = (state.period + haptic->pwm_duty) / 2;
+	state.enabled = true;
+
+	error = pwm_apply_might_sleep(haptic->pwm_dev, &state);
+	if (error) {
+		dev_err(haptic->dev,
+			"failed to enable haptic pwm device: %d\n", error);
+		return;
+	}
+
+	error = max77693_haptic_lowsys(haptic, true);
+	if (error)
+		goto err_enable_lowsys;
+
+	error = max77693_haptic_configure(haptic, true);
+	if (error)
+		goto err_enable_config;
+
+	haptic->enabled = true;
+
+	return;
+
+err_enable_config:
+	max77693_haptic_lowsys(haptic, false);
+err_enable_lowsys:
+	pwm_disable(haptic->pwm_dev);
+}
+
+static void max77693_haptic_disable(struct max77693_haptic *haptic)
+{
+	int error;
+
+	if (!haptic->enabled)
+		return;
+
+	error = max77693_haptic_configure(haptic, false);
+	if (error)
+		return;
+
+	error = max77693_haptic_lowsys(haptic, false);
+	if (error)
+		goto err_disable_lowsys;
+
+	pwm_disable(haptic->pwm_dev);
+	haptic->enabled = false;
+
+	return;
+
+err_disable_lowsys:
+	max77693_haptic_configure(haptic, true);
+}
+
+static void max77693_haptic_play_work(struct work_struct *work)
+{
+	struct max77693_haptic *haptic =
+			container_of(work, struct max77693_haptic, work);
+
+	if (!haptic->magnitude)
+		max77693_haptic_disable(haptic);
+	else if (haptic->enabled)
+		max77693_haptic_set_duty_cycle(haptic);
+	else
+		max77693_haptic_enable(haptic);
+}
+
+static int max77693_haptic_play_effect(struct input_dev *dev, void *data,
+				       struct ff_effect *effect)
+{
+	struct max77693_haptic *haptic = input_get_drvdata(dev);
+	struct pwm_args pargs;
+	u64 period_mag_multi;
+
+	haptic->magnitude = effect->u.rumble.strong_magnitude;
+	if (!haptic->magnitude)
+		haptic->magnitude = effect->u.rumble.weak_magnitude;
+
+	/*
+	 * The magnitude comes from force-feedback interface.
+	 * The formula to convert magnitude to pwm_duty as follows:
+	 * - pwm_duty = (magnitude * pwm_period) / MAX_MAGNITUDE(0xFFFF)
+	 */
+	pwm_get_args(haptic->pwm_dev, &pargs);
+	period_mag_multi = (u64)pargs.period * haptic->magnitude;
+	haptic->pwm_duty = (unsigned int)(period_mag_multi >>
+						MAX_MAGNITUDE_SHIFT);
+
+	schedule_work(&haptic->work);
+
+	return 0;
+}
+
+static int max77693_haptic_open(struct input_dev *dev)
+{
+	struct max77693_haptic *haptic = input_get_drvdata(dev);
+	int error;
+
+	error = max77843_haptic_bias(haptic, true);
+	if (error)
+		return error;
+
+	error = regulator_enable(haptic->motor_reg);
+	if (error) {
+		dev_err(haptic->dev,
+			"failed to enable regulator: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static void max77693_haptic_close(struct input_dev *dev)
+{
+	struct max77693_haptic *haptic = input_get_drvdata(dev);
+	int error;
+
+	cancel_work_sync(&haptic->work);
+	max77693_haptic_disable(haptic);
+
+	error = regulator_disable(haptic->motor_reg);
+	if (error)
+		dev_err(haptic->dev,
+			"failed to disable regulator: %d\n", error);
+
+	max77843_haptic_bias(haptic, false);
+}
+
+static int max77693_haptic_probe(struct platform_device *pdev)
+{
+	struct max77693_dev *max77693 = dev_get_drvdata(pdev->dev.parent);
+	struct max77693_haptic *haptic;
+	int error;
+
+	haptic = devm_kzalloc(&pdev->dev, sizeof(*haptic), GFP_KERNEL);
+	if (!haptic)
+		return -ENOMEM;
+
+	haptic->regmap_pmic = max77693->regmap;
+	haptic->dev = &pdev->dev;
+	haptic->type = MAX77693_HAPTIC_LRA;
+	haptic->mode = MAX77693_HAPTIC_EXTERNAL_MODE;
+	haptic->suspend_state = false;
+
+	/* Variant-specific init */
+	haptic->dev_type = max77693->type;
+	switch (haptic->dev_type) {
+	case TYPE_MAX77693:
+		haptic->regmap_haptic = max77693->regmap_haptic;
+		break;
+	case TYPE_MAX77705:
+	case TYPE_MAX77843:
+		haptic->regmap_haptic = max77693->regmap;
+		break;
+	default:
+		dev_err(&pdev->dev, "unsupported device type: %u\n",
+			haptic->dev_type);
+		return -EINVAL;
+	}
+
+	INIT_WORK(&haptic->work, max77693_haptic_play_work);
+
+	/* Get pwm and regulatot for haptic device */
+	haptic->pwm_dev = devm_pwm_get(&pdev->dev, NULL);
+	if (IS_ERR(haptic->pwm_dev)) {
+		dev_err(&pdev->dev, "failed to get pwm device\n");
+		return PTR_ERR(haptic->pwm_dev);
+	}
+
+	haptic->motor_reg = devm_regulator_get(&pdev->dev, "haptic");
+	if (IS_ERR(haptic->motor_reg)) {
+		dev_err(&pdev->dev, "failed to get regulator\n");
+		return PTR_ERR(haptic->motor_reg);
+	}
+
+	/* Initialize input device for haptic device */
+	haptic->input_dev = devm_input_allocate_device(&pdev->dev);
+	if (!haptic->input_dev) {
+		dev_err(&pdev->dev, "failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	haptic->input_dev->name = "max77693-haptic";
+	haptic->input_dev->id.version = 1;
+	haptic->input_dev->dev.parent = &pdev->dev;
+	haptic->input_dev->open = max77693_haptic_open;
+	haptic->input_dev->close = max77693_haptic_close;
+	input_set_drvdata(haptic->input_dev, haptic);
+	input_set_capability(haptic->input_dev, EV_FF, FF_RUMBLE);
+
+	error = input_ff_create_memless(haptic->input_dev, NULL,
+				max77693_haptic_play_effect);
+	if (error) {
+		dev_err(&pdev->dev, "failed to create force-feedback\n");
+		return error;
+	}
+
+	error = input_register_device(haptic->input_dev);
+	if (error) {
+		dev_err(&pdev->dev, "failed to register input device\n");
+		return error;
+	}
+
+	platform_set_drvdata(pdev, haptic);
+
+	return 0;
+}
+
+static int max77693_haptic_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct max77693_haptic *haptic = platform_get_drvdata(pdev);
+
+	if (haptic->enabled) {
+		max77693_haptic_disable(haptic);
+		haptic->suspend_state = true;
+	}
+
+	return 0;
+}
+
+static int max77693_haptic_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct max77693_haptic *haptic = platform_get_drvdata(pdev);
+
+	if (haptic->suspend_state) {
+		max77693_haptic_enable(haptic);
+		haptic->suspend_state = false;
+	}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(max77693_haptic_pm_ops,
+				max77693_haptic_suspend,
+				max77693_haptic_resume);
+
+static const struct platform_device_id max77693_haptic_id[] = {
+	{ "max77693-haptic", },
+	{ "max77705-haptic", },
+	{ "max77843-haptic", },
+	{},
+};
+MODULE_DEVICE_TABLE(platform, max77693_haptic_id);
+
+static const struct of_device_id of_max77693_haptic_dt_match[] = {
+	{ .compatible = "maxim,max77693-haptic", },
+	{ .compatible = "maxim,max77705-haptic", },
+	{ .compatible = "maxim,max77843-haptic", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, of_max77693_haptic_dt_match);
+
+static struct platform_driver max77693_haptic_driver = {
+	.driver		= {
+		.name	= "max77693-haptic",
+		.pm	= pm_sleep_ptr(&max77693_haptic_pm_ops),
+		.of_match_table = of_max77693_haptic_dt_match,
+	},
+	.probe		= max77693_haptic_probe,
+	.id_table	= max77693_haptic_id,
+};
+module_platform_driver(max77693_haptic_driver);
+
+MODULE_AUTHOR("Jaewon Kim <jaewon02.kim@samsung.com>");
+MODULE_AUTHOR("Krzysztof Kozlowski <krzk@kernel.org>");
+MODULE_DESCRIPTION("MAXIM 77693/77705/77843 Haptic driver");
+MODULE_LICENSE("GPL");