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, 367 insertions, 0 deletions

diff --git a/drivers/mfd/pf1550.c b/drivers/mfd/pf1550.c
new file mode 100644
index 000000000..c4f567c05
--- /dev/null
+++ b/drivers/mfd/pf1550.c
@@ -0,0 +1,367 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Core driver for the PF1550
+ *
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ * Robin Gong <yibin.gong@freescale.com>
+ *
+ * Portions Copyright (c) 2025 Savoir-faire Linux Inc.
+ * Samuel Kayode <samuel.kayode@savoirfairelinux.com>
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/pf1550.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+static const struct regmap_config pf1550_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = PF1550_PMIC_REG_END,
+};
+
+static const struct regmap_irq pf1550_irqs[] = {
+	REGMAP_IRQ_REG(PF1550_IRQ_CHG, 0, IRQ_CHG),
+	REGMAP_IRQ_REG(PF1550_IRQ_REGULATOR, 0, IRQ_REGULATOR),
+	REGMAP_IRQ_REG(PF1550_IRQ_ONKEY, 0, IRQ_ONKEY),
+};
+
+static const struct regmap_irq_chip pf1550_irq_chip = {
+	.name = "pf1550",
+	.status_base = PF1550_PMIC_REG_INT_CATEGORY,
+	.init_ack_masked = 1,
+	.num_regs = 1,
+	.irqs = pf1550_irqs,
+	.num_irqs = ARRAY_SIZE(pf1550_irqs),
+};
+
+static const struct regmap_irq pf1550_regulator_irqs[] = {
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_SW1_LS, 0, PMIC_IRQ_SW1_LS),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_SW2_LS, 0, PMIC_IRQ_SW2_LS),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_SW3_LS, 0, PMIC_IRQ_SW3_LS),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_SW1_HS, 3, PMIC_IRQ_SW1_HS),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_SW2_HS, 3, PMIC_IRQ_SW2_HS),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_SW3_HS, 3, PMIC_IRQ_SW3_HS),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_LDO1_FAULT, 16, PMIC_IRQ_LDO1_FAULT),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_LDO2_FAULT, 16, PMIC_IRQ_LDO2_FAULT),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_LDO3_FAULT, 16, PMIC_IRQ_LDO3_FAULT),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_TEMP_110, 24, PMIC_IRQ_TEMP_110),
+	REGMAP_IRQ_REG(PF1550_PMIC_IRQ_TEMP_125, 24, PMIC_IRQ_TEMP_125),
+};
+
+static const struct regmap_irq_chip pf1550_regulator_irq_chip = {
+	.name = "pf1550-regulator",
+	.status_base = PF1550_PMIC_REG_SW_INT_STAT0,
+	.ack_base = PF1550_PMIC_REG_SW_INT_STAT0,
+	.mask_base = PF1550_PMIC_REG_SW_INT_MASK0,
+	.use_ack = 1,
+	.init_ack_masked = 1,
+	.num_regs = 25,
+	.irqs = pf1550_regulator_irqs,
+	.num_irqs = ARRAY_SIZE(pf1550_regulator_irqs),
+};
+
+static const struct resource regulator_resources[] = {
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_SW1_LS),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_SW2_LS),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_SW3_LS),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_SW1_HS),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_SW2_HS),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_SW3_HS),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_LDO1_FAULT),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_LDO2_FAULT),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_LDO3_FAULT),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_TEMP_110),
+	DEFINE_RES_IRQ(PF1550_PMIC_IRQ_TEMP_125),
+};
+
+static const struct regmap_irq pf1550_onkey_irqs[] = {
+	REGMAP_IRQ_REG(PF1550_ONKEY_IRQ_PUSHI, 0, ONKEY_IRQ_PUSHI),
+	REGMAP_IRQ_REG(PF1550_ONKEY_IRQ_1SI, 0, ONKEY_IRQ_1SI),
+	REGMAP_IRQ_REG(PF1550_ONKEY_IRQ_2SI, 0, ONKEY_IRQ_2SI),
+	REGMAP_IRQ_REG(PF1550_ONKEY_IRQ_3SI, 0, ONKEY_IRQ_3SI),
+	REGMAP_IRQ_REG(PF1550_ONKEY_IRQ_4SI, 0, ONKEY_IRQ_4SI),
+	REGMAP_IRQ_REG(PF1550_ONKEY_IRQ_8SI, 0, ONKEY_IRQ_8SI),
+};
+
+static const struct regmap_irq_chip pf1550_onkey_irq_chip = {
+	.name = "pf1550-onkey",
+	.status_base = PF1550_PMIC_REG_ONKEY_INT_STAT0,
+	.ack_base = PF1550_PMIC_REG_ONKEY_INT_STAT0,
+	.mask_base = PF1550_PMIC_REG_ONKEY_INT_MASK0,
+	.use_ack = 1,
+	.init_ack_masked = 1,
+	.num_regs = 1,
+	.irqs = pf1550_onkey_irqs,
+	.num_irqs = ARRAY_SIZE(pf1550_onkey_irqs),
+};
+
+static const struct resource onkey_resources[] = {
+	DEFINE_RES_IRQ(PF1550_ONKEY_IRQ_PUSHI),
+	DEFINE_RES_IRQ(PF1550_ONKEY_IRQ_1SI),
+	DEFINE_RES_IRQ(PF1550_ONKEY_IRQ_2SI),
+	DEFINE_RES_IRQ(PF1550_ONKEY_IRQ_3SI),
+	DEFINE_RES_IRQ(PF1550_ONKEY_IRQ_4SI),
+	DEFINE_RES_IRQ(PF1550_ONKEY_IRQ_8SI),
+};
+
+static const struct regmap_irq pf1550_charger_irqs[] = {
+	REGMAP_IRQ_REG(PF1550_CHARG_IRQ_BAT2SOCI, 0, CHARG_IRQ_BAT2SOCI),
+	REGMAP_IRQ_REG(PF1550_CHARG_IRQ_BATI, 0, CHARG_IRQ_BATI),
+	REGMAP_IRQ_REG(PF1550_CHARG_IRQ_CHGI, 0, CHARG_IRQ_CHGI),
+	REGMAP_IRQ_REG(PF1550_CHARG_IRQ_VBUSI, 0, CHARG_IRQ_VBUSI),
+	REGMAP_IRQ_REG(PF1550_CHARG_IRQ_THMI, 0, CHARG_IRQ_THMI),
+};
+
+static const struct regmap_irq_chip pf1550_charger_irq_chip = {
+	.name = "pf1550-charger",
+	.status_base = PF1550_CHARG_REG_CHG_INT,
+	.ack_base = PF1550_CHARG_REG_CHG_INT,
+	.mask_base = PF1550_CHARG_REG_CHG_INT_MASK,
+	.use_ack = 1,
+	.init_ack_masked = 1,
+	.num_regs = 1,
+	.irqs = pf1550_charger_irqs,
+	.num_irqs = ARRAY_SIZE(pf1550_charger_irqs),
+};
+
+static const struct resource charger_resources[] = {
+	DEFINE_RES_IRQ(PF1550_CHARG_IRQ_BAT2SOCI),
+	DEFINE_RES_IRQ(PF1550_CHARG_IRQ_BATI),
+	DEFINE_RES_IRQ(PF1550_CHARG_IRQ_CHGI),
+	DEFINE_RES_IRQ(PF1550_CHARG_IRQ_VBUSI),
+	DEFINE_RES_IRQ(PF1550_CHARG_IRQ_THMI),
+};
+
+static const struct mfd_cell pf1550_regulator_cell = {
+	.name = "pf1550-regulator",
+	.num_resources = ARRAY_SIZE(regulator_resources),
+	.resources = regulator_resources,
+};
+
+static const struct mfd_cell pf1550_onkey_cell = {
+	.name = "pf1550-onkey",
+	.num_resources = ARRAY_SIZE(onkey_resources),
+	.resources = onkey_resources,
+};
+
+static const struct mfd_cell pf1550_charger_cell = {
+	.name = "pf1550-charger",
+	.num_resources = ARRAY_SIZE(charger_resources),
+	.resources = charger_resources,
+};
+
+/*
+ * The PF1550 is shipped in variants of A0, A1,...A9. Each variant defines a
+ * configuration of the PMIC in a One-Time Programmable (OTP) memory.
+ * This memory is accessed indirectly by writing valid keys to specific
+ * registers of the PMIC. To read the OTP memory after writing the valid keys,
+ * the OTP register address to be read is written to pf1550 register 0xc4 and
+ * its value read from pf1550 register 0xc5.
+ */
+static int pf1550_read_otp(const struct pf1550_ddata *pf1550, unsigned int index,
+			   unsigned int *val)
+{
+	int ret = 0;
+
+	ret = regmap_write(pf1550->regmap, PF1550_PMIC_REG_KEY, PF1550_OTP_PMIC_KEY);
+	if (ret)
+		goto read_err;
+
+	ret = regmap_write(pf1550->regmap, PF1550_CHARG_REG_CHGR_KEY2, PF1550_OTP_CHGR_KEY);
+	if (ret)
+		goto read_err;
+
+	ret = regmap_write(pf1550->regmap, PF1550_TEST_REG_KEY3, PF1550_OTP_TEST_KEY);
+	if (ret)
+		goto read_err;
+
+	ret = regmap_write(pf1550->regmap, PF1550_TEST_REG_FMRADDR, index);
+	if (ret)
+		goto read_err;
+
+	ret = regmap_read(pf1550->regmap, PF1550_TEST_REG_FMRDATA, val);
+	if (ret)
+		goto read_err;
+
+	return 0;
+
+read_err:
+	return dev_err_probe(pf1550->dev, ret, "OTP reg %x not found!\n", index);
+}
+
+static int pf1550_i2c_probe(struct i2c_client *i2c)
+{
+	const struct mfd_cell *regulator = &pf1550_regulator_cell;
+	const struct mfd_cell *charger = &pf1550_charger_cell;
+	const struct mfd_cell *onkey = &pf1550_onkey_cell;
+	unsigned int reg_data = 0, otp_data = 0;
+	struct pf1550_ddata *pf1550;
+	struct irq_domain *domain;
+	int irq, ret = 0;
+
+	pf1550 = devm_kzalloc(&i2c->dev, sizeof(*pf1550), GFP_KERNEL);
+	if (!pf1550)
+		return -ENOMEM;
+
+	i2c_set_clientdata(i2c, pf1550);
+	pf1550->dev = &i2c->dev;
+	pf1550->irq = i2c->irq;
+
+	pf1550->regmap = devm_regmap_init_i2c(i2c, &pf1550_regmap_config);
+	if (IS_ERR(pf1550->regmap))
+		return dev_err_probe(pf1550->dev, PTR_ERR(pf1550->regmap),
+				     "failed to allocate register map\n");
+
+	ret = regmap_read(pf1550->regmap, PF1550_PMIC_REG_DEVICE_ID, &reg_data);
+	if (ret < 0)
+		return dev_err_probe(pf1550->dev, ret, "cannot read chip ID\n");
+	if (reg_data != PF1550_DEVICE_ID)
+		return dev_err_probe(pf1550->dev, -ENODEV, "invalid device ID: 0x%02x\n", reg_data);
+
+	/* Regulator DVS for SW2 */
+	ret = pf1550_read_otp(pf1550, PF1550_OTP_SW2_SW3, &otp_data);
+	if (ret)
+		return ret;
+
+	/* When clear, DVS should be enabled */
+	if (!(otp_data & OTP_SW2_DVS_ENB))
+		pf1550->dvs2_enable = true;
+
+	/* Regulator DVS for SW1 */
+	ret = pf1550_read_otp(pf1550, PF1550_OTP_SW1_SW2, &otp_data);
+	if (ret)
+		return ret;
+
+	if (!(otp_data & OTP_SW1_DVS_ENB))
+		pf1550->dvs1_enable = true;
+
+	/* Add top level interrupts */
+	ret = devm_regmap_add_irq_chip(pf1550->dev, pf1550->regmap, pf1550->irq,
+				       IRQF_ONESHOT | IRQF_SHARED |
+				       IRQF_TRIGGER_FALLING,
+				       0, &pf1550_irq_chip,
+				       &pf1550->irq_data);
+	if (ret)
+		return ret;
+
+	/* Add regulator */
+	irq = regmap_irq_get_virq(pf1550->irq_data, PF1550_IRQ_REGULATOR);
+	if (irq < 0)
+		return dev_err_probe(pf1550->dev, irq,
+				     "Failed to get parent vIRQ(%d) for chip %s\n",
+				     PF1550_IRQ_REGULATOR, pf1550_irq_chip.name);
+
+	ret = devm_regmap_add_irq_chip(pf1550->dev, pf1550->regmap, irq,
+				       IRQF_ONESHOT | IRQF_SHARED |
+				       IRQF_TRIGGER_FALLING, 0,
+				       &pf1550_regulator_irq_chip,
+				       &pf1550->irq_data_regulator);
+	if (ret)
+		return dev_err_probe(pf1550->dev, ret, "Failed to add %s IRQ chip\n",
+				     pf1550_regulator_irq_chip.name);
+
+	domain = regmap_irq_get_domain(pf1550->irq_data_regulator);
+
+	ret = devm_mfd_add_devices(pf1550->dev, PLATFORM_DEVID_NONE, regulator, 1, NULL, 0, domain);
+	if (ret)
+		return ret;
+
+	/* Add onkey */
+	irq = regmap_irq_get_virq(pf1550->irq_data, PF1550_IRQ_ONKEY);
+	if (irq < 0)
+		return dev_err_probe(pf1550->dev, irq,
+				     "Failed to get parent vIRQ(%d) for chip %s\n",
+				     PF1550_IRQ_ONKEY, pf1550_irq_chip.name);
+
+	ret = devm_regmap_add_irq_chip(pf1550->dev, pf1550->regmap, irq,
+				       IRQF_ONESHOT | IRQF_SHARED |
+				       IRQF_TRIGGER_FALLING, 0,
+				       &pf1550_onkey_irq_chip,
+				       &pf1550->irq_data_onkey);
+	if (ret)
+		return dev_err_probe(pf1550->dev, ret, "Failed to add %s IRQ chip\n",
+				     pf1550_onkey_irq_chip.name);
+
+	domain = regmap_irq_get_domain(pf1550->irq_data_onkey);
+
+	ret = devm_mfd_add_devices(pf1550->dev, PLATFORM_DEVID_NONE, onkey, 1, NULL, 0, domain);
+	if (ret)
+		return ret;
+
+	/* Add battery charger */
+	irq = regmap_irq_get_virq(pf1550->irq_data, PF1550_IRQ_CHG);
+	if (irq < 0)
+		return dev_err_probe(pf1550->dev, irq,
+				     "Failed to get parent vIRQ(%d) for chip %s\n",
+				     PF1550_IRQ_CHG, pf1550_irq_chip.name);
+
+	ret = devm_regmap_add_irq_chip(pf1550->dev, pf1550->regmap, irq,
+				       IRQF_ONESHOT | IRQF_SHARED |
+				       IRQF_TRIGGER_FALLING, 0,
+				       &pf1550_charger_irq_chip,
+				       &pf1550->irq_data_charger);
+	if (ret)
+		return dev_err_probe(pf1550->dev, ret, "Failed to add %s IRQ chip\n",
+				     pf1550_charger_irq_chip.name);
+
+	domain = regmap_irq_get_domain(pf1550->irq_data_charger);
+
+	return devm_mfd_add_devices(pf1550->dev, PLATFORM_DEVID_NONE, charger, 1, NULL, 0, domain);
+}
+
+static int pf1550_suspend(struct device *dev)
+{
+	struct pf1550_ddata *pf1550 = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev)) {
+		enable_irq_wake(pf1550->irq);
+		disable_irq(pf1550->irq);
+	}
+
+	return 0;
+}
+
+static int pf1550_resume(struct device *dev)
+{
+	struct pf1550_ddata *pf1550 = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev)) {
+		disable_irq_wake(pf1550->irq);
+		enable_irq(pf1550->irq);
+	}
+
+	return 0;
+}
+static DEFINE_SIMPLE_DEV_PM_OPS(pf1550_pm, pf1550_suspend, pf1550_resume);
+
+static const struct i2c_device_id pf1550_i2c_id[] = {
+	{ "pf1550" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, pf1550_i2c_id);
+
+static const struct of_device_id pf1550_dt_match[] = {
+	{ .compatible = "nxp,pf1550" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pf1550_dt_match);
+
+static struct i2c_driver pf1550_i2c_driver = {
+	.driver = {
+		   .name = "pf1550",
+		   .pm = pm_sleep_ptr(&pf1550_pm),
+		   .of_match_table = pf1550_dt_match,
+	},
+	.probe = pf1550_i2c_probe,
+	.id_table = pf1550_i2c_id,
+};
+module_i2c_driver(pf1550_i2c_driver);
+
+MODULE_DESCRIPTION("NXP PF1550 core driver");
+MODULE_AUTHOR("Robin Gong <yibin.gong@freescale.com>");
+MODULE_LICENSE("GPL");