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, 357 insertions, 0 deletions

diff --git a/drivers/mfd/tps65218.c b/drivers/mfd/tps65218.c
new file mode 100644
index 000000000..4f3e632f7
--- /dev/null
+++ b/drivers/mfd/tps65218.c
@@ -0,0 +1,357 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for TPS65218 Integrated power management chipsets
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - https://www.ti.com/
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+
+#include <linux/mfd/core.h>
+#include <linux/mfd/tps65218.h>
+
+#define TPS65218_PASSWORD_REGS_UNLOCK   0x7D
+
+static const struct mfd_cell tps65218_cells[] = {
+	{
+		.name = "tps65218-pwrbutton",
+		.of_compatible = "ti,tps65218-pwrbutton",
+	},
+	{
+		.name = "tps65218-gpio",
+		.of_compatible = "ti,tps65218-gpio",
+	},
+	{ .name = "tps65218-regulator", },
+};
+
+/**
+ * tps65218_reg_write: Write a single tps65218 register.
+ *
+ * @tps: Device to write to.
+ * @reg: Register to write to.
+ * @val: Value to write.
+ * @level: Password protected level
+ */
+int tps65218_reg_write(struct tps65218 *tps, unsigned int reg,
+			unsigned int val, unsigned int level)
+{
+	int ret;
+	unsigned int xor_reg_val;
+
+	switch (level) {
+	case TPS65218_PROTECT_NONE:
+		return regmap_write(tps->regmap, reg, val);
+	case TPS65218_PROTECT_L1:
+		xor_reg_val = reg ^ TPS65218_PASSWORD_REGS_UNLOCK;
+		ret = regmap_write(tps->regmap, TPS65218_REG_PASSWORD,
+							xor_reg_val);
+		if (ret < 0)
+			return ret;
+
+		return regmap_write(tps->regmap, reg, val);
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL_GPL(tps65218_reg_write);
+
+/**
+ * tps65218_update_bits: Modify bits w.r.t mask, val and level.
+ *
+ * @tps: Device to write to.
+ * @reg: Register to read-write to.
+ * @mask: Mask.
+ * @val: Value to write.
+ * @level: Password protected level
+ */
+static int tps65218_update_bits(struct tps65218 *tps, unsigned int reg,
+		unsigned int mask, unsigned int val, unsigned int level)
+{
+	int ret;
+	unsigned int data;
+
+	ret = regmap_read(tps->regmap, reg, &data);
+	if (ret) {
+		dev_err(tps->dev, "Read from reg 0x%x failed\n", reg);
+		return ret;
+	}
+
+	data &= ~mask;
+	data |= val & mask;
+
+	mutex_lock(&tps->tps_lock);
+	ret = tps65218_reg_write(tps, reg, data, level);
+	if (ret)
+		dev_err(tps->dev, "Write for reg 0x%x failed\n", reg);
+	mutex_unlock(&tps->tps_lock);
+
+	return ret;
+}
+
+int tps65218_set_bits(struct tps65218 *tps, unsigned int reg,
+		unsigned int mask, unsigned int val, unsigned int level)
+{
+	return tps65218_update_bits(tps, reg, mask, val, level);
+}
+EXPORT_SYMBOL_GPL(tps65218_set_bits);
+
+int tps65218_clear_bits(struct tps65218 *tps, unsigned int reg,
+		unsigned int mask, unsigned int level)
+{
+	return tps65218_update_bits(tps, reg, mask, 0, level);
+}
+EXPORT_SYMBOL_GPL(tps65218_clear_bits);
+
+static const struct regmap_range tps65218_yes_ranges[] = {
+	regmap_reg_range(TPS65218_REG_INT1, TPS65218_REG_INT2),
+	regmap_reg_range(TPS65218_REG_STATUS, TPS65218_REG_STATUS),
+};
+
+static const struct regmap_access_table tps65218_volatile_table = {
+	.yes_ranges = tps65218_yes_ranges,
+	.n_yes_ranges = ARRAY_SIZE(tps65218_yes_ranges),
+};
+
+static const struct regmap_config tps65218_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_MAPLE,
+	.volatile_table = &tps65218_volatile_table,
+};
+
+static const struct regmap_irq tps65218_irqs[] = {
+	/* INT1 IRQs */
+	[TPS65218_PRGC_IRQ] = {
+		.mask = TPS65218_INT1_PRGC,
+	},
+	[TPS65218_CC_AQC_IRQ] = {
+		.mask = TPS65218_INT1_CC_AQC,
+	},
+	[TPS65218_HOT_IRQ] = {
+		.mask = TPS65218_INT1_HOT,
+	},
+	[TPS65218_PB_IRQ] = {
+		.mask = TPS65218_INT1_PB,
+	},
+	[TPS65218_AC_IRQ] = {
+		.mask = TPS65218_INT1_AC,
+	},
+	[TPS65218_VPRG_IRQ] = {
+		.mask = TPS65218_INT1_VPRG,
+	},
+	[TPS65218_INVALID1_IRQ] = {
+	},
+	[TPS65218_INVALID2_IRQ] = {
+	},
+	/* INT2 IRQs*/
+	[TPS65218_LS1_I_IRQ] = {
+		.mask = TPS65218_INT2_LS1_I,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS2_I_IRQ] = {
+		.mask = TPS65218_INT2_LS2_I,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS3_I_IRQ] = {
+		.mask = TPS65218_INT2_LS3_I,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS1_F_IRQ] = {
+		.mask = TPS65218_INT2_LS1_F,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS2_F_IRQ] = {
+		.mask = TPS65218_INT2_LS2_F,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS3_F_IRQ] = {
+		.mask = TPS65218_INT2_LS3_F,
+		.reg_offset = 1,
+	},
+	[TPS65218_INVALID3_IRQ] = {
+	},
+	[TPS65218_INVALID4_IRQ] = {
+	},
+};
+
+static const struct regmap_irq_chip tps65218_irq_chip = {
+	.name = "tps65218",
+	.irqs = tps65218_irqs,
+	.num_irqs = ARRAY_SIZE(tps65218_irqs),
+
+	.num_regs = 2,
+	.mask_base = TPS65218_REG_INT_MASK1,
+	.status_base = TPS65218_REG_INT1,
+};
+
+static const struct of_device_id of_tps65218_match_table[] = {
+	{ .compatible = "ti,tps65218", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_tps65218_match_table);
+
+static int tps65218_voltage_set_strict(struct tps65218 *tps)
+{
+	u32 strict;
+
+	if (of_property_read_u32(tps->dev->of_node,
+				 "ti,strict-supply-voltage-supervision",
+				 &strict))
+		return 0;
+
+	if (strict != 0 && strict != 1) {
+		dev_err(tps->dev,
+			"Invalid ti,strict-supply-voltage-supervision value\n");
+		return -EINVAL;
+	}
+
+	tps65218_update_bits(tps, TPS65218_REG_CONFIG1,
+			     TPS65218_CONFIG1_STRICT,
+			     strict ? TPS65218_CONFIG1_STRICT : 0,
+			     TPS65218_PROTECT_L1);
+	return 0;
+}
+
+static int tps65218_voltage_set_uv_hyst(struct tps65218 *tps)
+{
+	u32 hyst;
+
+	if (of_property_read_u32(tps->dev->of_node,
+				 "ti,under-voltage-hyst-microvolt", &hyst))
+		return 0;
+
+	if (hyst != 400000 && hyst != 200000) {
+		dev_err(tps->dev,
+			"Invalid ti,under-voltage-hyst-microvolt value\n");
+		return -EINVAL;
+	}
+
+	tps65218_update_bits(tps, TPS65218_REG_CONFIG2,
+			     TPS65218_CONFIG2_UVLOHYS,
+			     hyst == 400000 ? TPS65218_CONFIG2_UVLOHYS : 0,
+			     TPS65218_PROTECT_L1);
+	return 0;
+}
+
+static int tps65218_voltage_set_uvlo(struct tps65218 *tps)
+{
+	u32 uvlo;
+	int uvloval;
+
+	if (of_property_read_u32(tps->dev->of_node,
+				 "ti,under-voltage-limit-microvolt", &uvlo))
+		return 0;
+
+	switch (uvlo) {
+	case 2750000:
+		uvloval = TPS65218_CONFIG1_UVLO_2750000;
+		break;
+	case 2950000:
+		uvloval = TPS65218_CONFIG1_UVLO_2950000;
+		break;
+	case 3250000:
+		uvloval = TPS65218_CONFIG1_UVLO_3250000;
+		break;
+	case 3350000:
+		uvloval = TPS65218_CONFIG1_UVLO_3350000;
+		break;
+	default:
+		dev_err(tps->dev,
+			"Invalid ti,under-voltage-limit-microvolt value\n");
+		return -EINVAL;
+	}
+
+	tps65218_update_bits(tps, TPS65218_REG_CONFIG1,
+			     TPS65218_CONFIG1_UVLO_MASK, uvloval,
+			     TPS65218_PROTECT_L1);
+	return 0;
+}
+
+static int tps65218_probe(struct i2c_client *client)
+{
+	struct tps65218 *tps;
+	int ret;
+	unsigned int chipid;
+
+	tps = devm_kzalloc(&client->dev, sizeof(*tps), GFP_KERNEL);
+	if (!tps)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, tps);
+	tps->dev = &client->dev;
+	tps->irq = client->irq;
+	tps->regmap = devm_regmap_init_i2c(client, &tps65218_regmap_config);
+	if (IS_ERR(tps->regmap)) {
+		ret = PTR_ERR(tps->regmap);
+		dev_err(tps->dev, "Failed to allocate register map: %d\n",
+			ret);
+		return ret;
+	}
+
+	mutex_init(&tps->tps_lock);
+
+	ret = devm_regmap_add_irq_chip(&client->dev, tps->regmap, tps->irq,
+				       IRQF_ONESHOT, 0, &tps65218_irq_chip,
+				       &tps->irq_data);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(tps->regmap, TPS65218_REG_CHIPID, &chipid);
+	if (ret) {
+		dev_err(tps->dev, "Failed to read chipid: %d\n", ret);
+		return ret;
+	}
+
+	tps->rev = chipid & TPS65218_CHIPID_REV_MASK;
+
+	ret = tps65218_voltage_set_strict(tps);
+	if (ret)
+		return ret;
+
+	ret = tps65218_voltage_set_uvlo(tps);
+	if (ret)
+		return ret;
+
+	ret = tps65218_voltage_set_uv_hyst(tps);
+	if (ret)
+		return ret;
+
+	ret = mfd_add_devices(tps->dev, PLATFORM_DEVID_AUTO, tps65218_cells,
+			      ARRAY_SIZE(tps65218_cells), NULL, 0,
+			      regmap_irq_get_domain(tps->irq_data));
+
+	return ret;
+}
+
+static const struct i2c_device_id tps65218_id_table[] = {
+	{ "tps65218", TPS65218 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, tps65218_id_table);
+
+static struct i2c_driver tps65218_driver = {
+	.driver		= {
+		.name	= "tps65218",
+		.of_match_table = of_tps65218_match_table,
+	},
+	.probe		= tps65218_probe,
+	.id_table       = tps65218_id_table,
+};
+
+module_i2c_driver(tps65218_driver);
+
+MODULE_AUTHOR("J Keerthy <j-keerthy@ti.com>");
+MODULE_DESCRIPTION("TPS65218 chip family multi-function driver");
+MODULE_LICENSE("GPL v2");