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, 312 insertions, 0 deletions

diff --git a/drivers/mfd/mt6370.c b/drivers/mfd/mt6370.c
new file mode 100644
index 000000000..c7c2efe35
--- /dev/null
+++ b/drivers/mfd/mt6370.c
@@ -0,0 +1,312 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Richtek Technology Corp.
+ *
+ * Author: ChiYuan Huang <cy_huang@richtek.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "mt6370.h"
+
+#define MT6370_REG_DEV_INFO	0x100
+#define MT6370_REG_CHG_IRQ1	0x1C0
+#define MT6370_REG_CHG_MASK1	0x1E0
+#define MT6370_REG_MAXADDR	0x1FF
+
+#define MT6370_VENID_MASK	GENMASK(7, 4)
+
+#define MT6370_NUM_IRQREGS	16
+#define MT6370_USBC_I2CADDR	0x4E
+#define MT6370_MAX_ADDRLEN	2
+
+#define MT6370_VENID_RT5081	0x8
+#define MT6370_VENID_RT5081A	0xA
+#define MT6370_VENID_MT6370	0xE
+#define MT6370_VENID_MT6371	0xF
+#define MT6370_VENID_MT6372P	0x9
+#define MT6370_VENID_MT6372CP	0xB
+
+static const struct regmap_irq mt6370_irqs[] = {
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHGON, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_TREG, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_AICR, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_MIVR, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_PWR_RDY, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FL_CHG_VINOVP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_VSYSUV, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_VSYSOV, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_VBATOV, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_VINOVPCHG, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_BAT_COLD, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_BAT_COOL, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_BAT_WARM, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_BAT_HOT, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_STATC, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_FAULT, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_STATC, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_TMR, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_BATABS, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_ADPBAD, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_RVP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_TSHUTDOWN, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_IINMEAS, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_ICCMEAS, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHGDET_DONE, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_WDTMR, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_SSFINISH, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_RECHG, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_TERM, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_IEOC, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_ADC_DONE, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_PUMPX_DONE, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_BST_BATUV, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_BST_MIDOV, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_BST_OLP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_ATTACH, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DETACH, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_HVDCP_STPDONE, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_HVDCP_VBUSDET_DONE, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_HVDCP_DET, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHGDET, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DCDT, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_VGOK, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_WDTMR, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_UC, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_OC, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_OV, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_SWON, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_UVP_D, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_UVP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_OVP_D, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_OVP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED_STRBPIN, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED_TORPIN, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED_TX, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED_LVF, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED2_SHORT, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED1_SHORT, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED2_STRB, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED1_STRB, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED2_STRB_TO, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED1_STRB_TO, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED2_TOR, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED1_TOR, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_OTP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_VDDA_OVP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_VDDA_UV, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_LDO_OC, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_BLED_OCP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_BLED_OVP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_VNEG_OCP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_VPOS_OCP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_BST_OCP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_VNEG_SCP, 8),
+	REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_VPOS_SCP, 8),
+};
+
+static const struct regmap_irq_chip mt6370_irq_chip = {
+	.name		= "mt6370-irqs",
+	.status_base	= MT6370_REG_CHG_IRQ1,
+	.mask_base	= MT6370_REG_CHG_MASK1,
+	.num_regs	= MT6370_NUM_IRQREGS,
+	.irqs		= mt6370_irqs,
+	.num_irqs	= ARRAY_SIZE(mt6370_irqs),
+};
+
+static const struct resource mt6370_regulator_irqs[] = {
+	DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_VPOS_SCP, "db_vpos_scp"),
+	DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_VNEG_SCP, "db_vneg_scp"),
+	DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_BST_OCP, "db_vbst_ocp"),
+	DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_VPOS_OCP, "db_vpos_ocp"),
+	DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_VNEG_OCP, "db_vneg_ocp"),
+	DEFINE_RES_IRQ_NAMED(MT6370_IRQ_LDO_OC, "ldo_oc"),
+};
+
+static const struct mfd_cell mt6370_devices[] = {
+	MFD_CELL_OF("mt6370-adc",
+		    NULL, NULL, 0, 0, "mediatek,mt6370-adc"),
+	MFD_CELL_OF("mt6370-charger",
+		    NULL, NULL, 0, 0, "mediatek,mt6370-charger"),
+	MFD_CELL_OF("mt6370-flashlight",
+		    NULL, NULL, 0, 0, "mediatek,mt6370-flashlight"),
+	MFD_CELL_OF("mt6370-indicator",
+		    NULL, NULL, 0, 0, "mediatek,mt6370-indicator"),
+	MFD_CELL_OF("mt6370-tcpc",
+		    NULL, NULL, 0, 0, "mediatek,mt6370-tcpc"),
+	MFD_CELL_RES("mt6370-regulator", mt6370_regulator_irqs),
+};
+
+static const struct mfd_cell mt6370_exclusive_devices[] = {
+	MFD_CELL_OF("mt6370-backlight",
+		    NULL, NULL, 0, 0, "mediatek,mt6370-backlight"),
+};
+
+static const struct mfd_cell mt6372_exclusive_devices[] = {
+	MFD_CELL_OF("mt6370-backlight",
+		    NULL, NULL, 0, 0, "mediatek,mt6372-backlight"),
+};
+
+static int mt6370_check_vendor_info(struct device *dev, struct regmap *rmap,
+				    int *vid)
+{
+	unsigned int devinfo;
+	int ret;
+
+	ret = regmap_read(rmap, MT6370_REG_DEV_INFO, &devinfo);
+	if (ret)
+		return ret;
+
+	*vid = FIELD_GET(MT6370_VENID_MASK, devinfo);
+	switch (*vid) {
+	case MT6370_VENID_RT5081:
+	case MT6370_VENID_RT5081A:
+	case MT6370_VENID_MT6370:
+	case MT6370_VENID_MT6371:
+	case MT6370_VENID_MT6372P:
+	case MT6370_VENID_MT6372CP:
+		return 0;
+	default:
+		dev_err(dev, "Unknown Vendor ID 0x%02x\n", devinfo);
+		return -ENODEV;
+	}
+}
+
+static int mt6370_regmap_read(void *context, const void *reg_buf,
+			      size_t reg_size, void *val_buf, size_t val_size)
+{
+	struct mt6370_info *info = context;
+	const u8 *u8_buf = reg_buf;
+	u8 bank_idx, bank_addr;
+	int ret;
+
+	bank_idx = u8_buf[0];
+	bank_addr = u8_buf[1];
+
+	ret = i2c_smbus_read_i2c_block_data(info->i2c[bank_idx], bank_addr,
+					    val_size, val_buf);
+	if (ret < 0)
+		return ret;
+
+	if (ret != val_size)
+		return -EIO;
+
+	return 0;
+}
+
+static int mt6370_regmap_write(void *context, const void *data, size_t count)
+{
+	struct mt6370_info *info = context;
+	const u8 *u8_buf = data;
+	u8 bank_idx, bank_addr;
+	int len = count - MT6370_MAX_ADDRLEN;
+
+	bank_idx = u8_buf[0];
+	bank_addr = u8_buf[1];
+
+	return i2c_smbus_write_i2c_block_data(info->i2c[bank_idx], bank_addr,
+					      len, data + MT6370_MAX_ADDRLEN);
+}
+
+static const struct regmap_bus mt6370_regmap_bus = {
+	.read		= mt6370_regmap_read,
+	.write		= mt6370_regmap_write,
+};
+
+static const struct regmap_config mt6370_regmap_config = {
+	.reg_bits		= 16,
+	.val_bits		= 8,
+	.reg_format_endian	= REGMAP_ENDIAN_BIG,
+	.max_register		= MT6370_REG_MAXADDR,
+};
+
+static int mt6370_probe(struct i2c_client *i2c)
+{
+	struct mt6370_info *info;
+	struct i2c_client *usbc_i2c;
+	struct regmap *regmap;
+	struct device *dev = &i2c->dev;
+	int ret, vid;
+
+	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	usbc_i2c = devm_i2c_new_dummy_device(dev, i2c->adapter,
+					     MT6370_USBC_I2CADDR);
+	if (IS_ERR(usbc_i2c))
+		return dev_err_probe(dev, PTR_ERR(usbc_i2c),
+				     "Failed to register USBC I2C client\n");
+
+	/* Assign I2C client for PMU and TypeC */
+	info->i2c[MT6370_PMU_I2C] = i2c;
+	info->i2c[MT6370_USBC_I2C] = usbc_i2c;
+
+	regmap = devm_regmap_init(dev, &mt6370_regmap_bus,
+				  info, &mt6370_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap),
+				     "Failed to init regmap\n");
+
+	ret = mt6370_check_vendor_info(dev, regmap, &vid);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to check vendor info\n");
+
+	ret = devm_regmap_add_irq_chip(dev, regmap, i2c->irq,
+				       IRQF_ONESHOT, -1, &mt6370_irq_chip,
+				       &info->irq_data);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to add irq chip\n");
+
+	switch (vid) {
+	case MT6370_VENID_MT6372P:
+	case MT6370_VENID_MT6372CP:
+		ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO,
+					   mt6372_exclusive_devices,
+					   ARRAY_SIZE(mt6372_exclusive_devices),
+					   NULL, 0,
+					   regmap_irq_get_domain(info->irq_data));
+		break;
+	default:
+		ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO,
+					   mt6370_exclusive_devices,
+					   ARRAY_SIZE(mt6370_exclusive_devices),
+					   NULL, 0,
+					   regmap_irq_get_domain(info->irq_data));
+		break;
+	}
+
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to add the exclusive devices\n");
+
+	return devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO,
+				    mt6370_devices, ARRAY_SIZE(mt6370_devices),
+				    NULL, 0,
+				    regmap_irq_get_domain(info->irq_data));
+}
+
+static const struct of_device_id mt6370_match_table[] = {
+	{ .compatible = "mediatek,mt6370" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mt6370_match_table);
+
+static struct i2c_driver mt6370_driver = {
+	.driver = {
+		.name = "mt6370",
+		.of_match_table = mt6370_match_table,
+	},
+	.probe = mt6370_probe,
+};
+module_i2c_driver(mt6370_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
+MODULE_DESCRIPTION("MediaTek MT6370 SubPMIC Driver");
+MODULE_LICENSE("GPL v2");