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, 661 insertions, 0 deletions

diff --git a/drivers/hwmon/sch5627.c b/drivers/hwmon/sch5627.c
new file mode 100644
index 000000000..04e701ce2
--- /dev/null
+++ b/drivers/hwmon/sch5627.c
@@ -0,0 +1,661 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/***************************************************************************
+ *   Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com>           *
+ *                                                                         *
+ ***************************************************************************/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bits.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/init.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/platform_device.h>
+#include <linux/hwmon.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include "sch56xx-common.h"
+
+#define DRVNAME "sch5627"
+#define DEVNAME DRVNAME /* We only support one model */
+
+#define SCH5627_HWMON_ID		0xa5
+#define SCH5627_COMPANY_ID		0x5c
+#define SCH5627_PRIMARY_ID		0xa0
+
+#define SCH5627_REG_BUILD_CODE		0x39
+#define SCH5627_REG_BUILD_ID		0x3a
+#define SCH5627_REG_HWMON_ID		0x3c
+#define SCH5627_REG_HWMON_REV		0x3d
+#define SCH5627_REG_COMPANY_ID		0x3e
+#define SCH5627_REG_PRIMARY_ID		0x3f
+#define SCH5627_REG_CTRL		0x40
+
+#define SCH5627_CTRL_START		BIT(0)
+#define SCH5627_CTRL_LOCK		BIT(1)
+#define SCH5627_CTRL_VBAT		BIT(4)
+
+#define SCH5627_NO_TEMPS		8
+#define SCH5627_NO_FANS			4
+#define SCH5627_NO_IN			5
+
+static const u16 SCH5627_REG_TEMP_MSB[SCH5627_NO_TEMPS] = {
+	0x2B, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x180, 0x181 };
+static const u16 SCH5627_REG_TEMP_LSN[SCH5627_NO_TEMPS] = {
+	0xE2, 0xE1, 0xE1, 0xE5, 0xE5, 0xE6, 0x182, 0x182 };
+static const u16 SCH5627_REG_TEMP_HIGH_NIBBLE[SCH5627_NO_TEMPS] = {
+	0, 0, 1, 1, 0, 0, 0, 1 };
+static const u16 SCH5627_REG_TEMP_HIGH[SCH5627_NO_TEMPS] = {
+	0x61, 0x57, 0x59, 0x5B, 0x5D, 0x5F, 0x184, 0x186 };
+static const u16 SCH5627_REG_TEMP_ABS[SCH5627_NO_TEMPS] = {
+	0x9B, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x1A8, 0x1A9 };
+
+static const u16 SCH5627_REG_FAN[SCH5627_NO_FANS] = {
+	0x2C, 0x2E, 0x30, 0x32 };
+static const u16 SCH5627_REG_FAN_MIN[SCH5627_NO_FANS] = {
+	0x62, 0x64, 0x66, 0x68 };
+
+static const u16 SCH5627_REG_PWM_MAP[SCH5627_NO_FANS] = {
+	0xA0, 0xA1, 0xA2, 0xA3 };
+
+static const u16 SCH5627_REG_IN_MSB[SCH5627_NO_IN] = {
+	0x22, 0x23, 0x24, 0x25, 0x189 };
+static const u16 SCH5627_REG_IN_LSN[SCH5627_NO_IN] = {
+	0xE4, 0xE4, 0xE3, 0xE3, 0x18A };
+static const u16 SCH5627_REG_IN_HIGH_NIBBLE[SCH5627_NO_IN] = {
+	1, 0, 1, 0, 1 };
+static const u16 SCH5627_REG_IN_FACTOR[SCH5627_NO_IN] = {
+	10745, 3660, 9765, 10745, 3660 };
+static const char * const SCH5627_IN_LABELS[SCH5627_NO_IN] = {
+	"VCC", "VTT", "VBAT", "VTR", "V_IN" };
+
+struct sch5627_data {
+	struct regmap *regmap;
+	unsigned short addr;
+	u8 control;
+
+	struct mutex update_lock;
+	unsigned long last_battery;	/* In jiffies */
+	char temp_valid;		/* !=0 if following fields are valid */
+	char fan_valid;
+	char in_valid;
+	unsigned long temp_last_updated;	/* In jiffies */
+	unsigned long fan_last_updated;
+	unsigned long in_last_updated;
+	u16 temp[SCH5627_NO_TEMPS];
+	u16 fan[SCH5627_NO_FANS];
+	u16 in[SCH5627_NO_IN];
+};
+
+static const struct regmap_range sch5627_tunables_ranges[] = {
+	regmap_reg_range(0x57, 0x57),
+	regmap_reg_range(0x59, 0x59),
+	regmap_reg_range(0x5B, 0x5B),
+	regmap_reg_range(0x5D, 0x5D),
+	regmap_reg_range(0x5F, 0x5F),
+	regmap_reg_range(0x61, 0x69),
+	regmap_reg_range(0x96, 0x9B),
+	regmap_reg_range(0xA0, 0xA3),
+	regmap_reg_range(0x184, 0x184),
+	regmap_reg_range(0x186, 0x186),
+	regmap_reg_range(0x1A8, 0x1A9),
+};
+
+static const struct regmap_access_table sch5627_tunables_table = {
+	.yes_ranges = sch5627_tunables_ranges,
+	.n_yes_ranges = ARRAY_SIZE(sch5627_tunables_ranges),
+};
+
+static const struct regmap_config sch5627_regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 8,
+	.wr_table = &sch5627_tunables_table,
+	.rd_table = &sch5627_tunables_table,
+	.cache_type = REGCACHE_MAPLE,
+	.use_single_read = true,
+	.use_single_write = true,
+	.can_sleep = true,
+};
+
+static int sch5627_update_temp(struct sch5627_data *data)
+{
+	int ret = 0;
+	int i, val;
+
+	mutex_lock(&data->update_lock);
+
+	/* Cache the values for 1 second */
+	if (time_after(jiffies, data->temp_last_updated + HZ) || !data->temp_valid) {
+		for (i = 0; i < SCH5627_NO_TEMPS; i++) {
+			val = sch56xx_read_virtual_reg12(data->addr, SCH5627_REG_TEMP_MSB[i],
+							 SCH5627_REG_TEMP_LSN[i],
+							 SCH5627_REG_TEMP_HIGH_NIBBLE[i]);
+			if (unlikely(val < 0)) {
+				ret = val;
+				goto abort;
+			}
+			data->temp[i] = val;
+		}
+		data->temp_last_updated = jiffies;
+		data->temp_valid = 1;
+	}
+abort:
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+static int sch5627_update_fan(struct sch5627_data *data)
+{
+	int ret = 0;
+	int i, val;
+
+	mutex_lock(&data->update_lock);
+
+	/* Cache the values for 1 second */
+	if (time_after(jiffies, data->fan_last_updated + HZ) || !data->fan_valid) {
+		for (i = 0; i < SCH5627_NO_FANS; i++) {
+			val = sch56xx_read_virtual_reg16(data->addr, SCH5627_REG_FAN[i]);
+			if (unlikely(val < 0)) {
+				ret = val;
+				goto abort;
+			}
+			data->fan[i] = val;
+		}
+		data->fan_last_updated = jiffies;
+		data->fan_valid = 1;
+	}
+abort:
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+static int sch5627_update_in(struct sch5627_data *data)
+{
+	int ret = 0;
+	int i, val;
+
+	mutex_lock(&data->update_lock);
+
+	/* Trigger a Vbat voltage measurement every 5 minutes */
+	if (time_after(jiffies, data->last_battery + 300 * HZ)) {
+		sch56xx_write_virtual_reg(data->addr, SCH5627_REG_CTRL,
+					  data->control | SCH5627_CTRL_VBAT);
+		data->last_battery = jiffies;
+	}
+
+	/* Cache the values for 1 second */
+	if (time_after(jiffies, data->in_last_updated + HZ) || !data->in_valid) {
+		for (i = 0; i < SCH5627_NO_IN; i++) {
+			val = sch56xx_read_virtual_reg12(data->addr, SCH5627_REG_IN_MSB[i],
+							 SCH5627_REG_IN_LSN[i],
+							 SCH5627_REG_IN_HIGH_NIBBLE[i]);
+			if (unlikely(val < 0)) {
+				ret = val;
+				goto abort;
+			}
+			data->in[i] = val;
+		}
+		data->in_last_updated = jiffies;
+		data->in_valid = 1;
+	}
+abort:
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+static int reg_to_temp(u16 reg)
+{
+	return (reg * 625) / 10 - 64000;
+}
+
+static int reg_to_temp_limit(u8 reg)
+{
+	return (reg - 64) * 1000;
+}
+
+static int reg_to_rpm(u16 reg)
+{
+	if (reg == 0)
+		return -EIO;
+	if (reg == 0xffff)
+		return 0;
+
+	return 5400540 / reg;
+}
+
+static u8 sch5627_temp_limit_to_reg(long value)
+{
+	long limit = (value / 1000) + 64;
+
+	return clamp_val(limit, 0, U8_MAX);
+}
+
+static u16 sch5627_rpm_to_reg(long value)
+{
+	long pulses;
+
+	if (value <= 0)
+		return U16_MAX - 1;
+
+	pulses = 5400540 / value;
+
+	return clamp_val(pulses, 1, U16_MAX - 1);
+}
+
+static umode_t sch5627_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
+				  int channel)
+{
+	const struct sch5627_data *data = drvdata;
+
+	/* Once the lock bit is set, the virtual registers become read-only
+	 * until the next power cycle.
+	 */
+	if (data->control & SCH5627_CTRL_LOCK)
+		return 0444;
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_max:
+		case hwmon_temp_crit:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_min:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_auto_channels_temp:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0444;
+}
+
+static int sch5627_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
+			long *val)
+{
+	struct sch5627_data *data = dev_get_drvdata(dev);
+	int ret, value;
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			ret = sch5627_update_temp(data);
+			if (ret < 0)
+				return ret;
+
+			*val = reg_to_temp(data->temp[channel]);
+			return 0;
+		case hwmon_temp_max:
+			ret = regmap_read(data->regmap, SCH5627_REG_TEMP_ABS[channel], &value);
+			if (ret < 0)
+				return ret;
+
+			*val = reg_to_temp_limit((u8)value);
+			return 0;
+		case hwmon_temp_crit:
+			ret = regmap_read(data->regmap, SCH5627_REG_TEMP_HIGH[channel], &value);
+			if (ret < 0)
+				return ret;
+
+			*val = reg_to_temp_limit((u8)value);
+			return 0;
+		case hwmon_temp_fault:
+			ret = sch5627_update_temp(data);
+			if (ret < 0)
+				return ret;
+
+			*val = (data->temp[channel] == 0);
+			return 0;
+		default:
+			break;
+		}
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			ret = sch5627_update_fan(data);
+			if (ret < 0)
+				return ret;
+
+			ret = reg_to_rpm(data->fan[channel]);
+			if (ret < 0)
+				return ret;
+
+			*val = ret;
+			return 0;
+		case hwmon_fan_min:
+			ret = sch56xx_regmap_read16(data->regmap, SCH5627_REG_FAN_MIN[channel],
+						    &value);
+			if (ret < 0)
+				return ret;
+
+			ret = reg_to_rpm((u16)value);
+			if (ret < 0)
+				return ret;
+
+			*val = ret;
+			return 0;
+		case hwmon_fan_fault:
+			ret = sch5627_update_fan(data);
+			if (ret < 0)
+				return ret;
+
+			*val = (data->fan[channel] == 0xffff);
+			return 0;
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_auto_channels_temp:
+			ret = regmap_read(data->regmap, SCH5627_REG_PWM_MAP[channel], &value);
+			if (ret < 0)
+				return ret;
+
+			*val = value;
+			return 0;
+		default:
+			break;
+		}
+		break;
+	case hwmon_in:
+		ret = sch5627_update_in(data);
+		if (ret < 0)
+			return ret;
+		switch (attr) {
+		case hwmon_in_input:
+			*val = DIV_ROUND_CLOSEST(data->in[channel] * SCH5627_REG_IN_FACTOR[channel],
+						 10000);
+			return 0;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int sch5627_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+			       int channel, const char **str)
+{
+	switch (type) {
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_label:
+			*str = SCH5627_IN_LABELS[channel];
+			return 0;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int sch5627_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
+			 long val)
+{
+	struct sch5627_data *data = dev_get_drvdata(dev);
+	u16 fan;
+	u8 temp;
+
+	switch (type) {
+	case hwmon_temp:
+		temp = sch5627_temp_limit_to_reg(val);
+
+		switch (attr) {
+		case hwmon_temp_max:
+			return regmap_write(data->regmap, SCH5627_REG_TEMP_ABS[channel], temp);
+		case hwmon_temp_crit:
+			return regmap_write(data->regmap, SCH5627_REG_TEMP_HIGH[channel], temp);
+		default:
+			break;
+		}
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_min:
+			fan = sch5627_rpm_to_reg(val);
+
+			return sch56xx_regmap_write16(data->regmap, SCH5627_REG_FAN_MIN[channel],
+						      fan);
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_auto_channels_temp:
+			/* registers are 8 bit wide */
+			if (val > U8_MAX || val < 0)
+				return -EINVAL;
+
+			return regmap_write(data->regmap, SCH5627_REG_PWM_MAP[channel], val);
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static const struct hwmon_ops sch5627_ops = {
+	.is_visible = sch5627_is_visible,
+	.read = sch5627_read,
+	.read_string = sch5627_read_string,
+	.write = sch5627_write,
+};
+
+static const struct hwmon_channel_info * const sch5627_info[] = {
+	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT
+			   ),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
+			   HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
+			   HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
+			   HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT
+			   ),
+	HWMON_CHANNEL_INFO(pwm,
+			   HWMON_PWM_AUTO_CHANNELS_TEMP,
+			   HWMON_PWM_AUTO_CHANNELS_TEMP,
+			   HWMON_PWM_AUTO_CHANNELS_TEMP,
+			   HWMON_PWM_AUTO_CHANNELS_TEMP
+			   ),
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT
+			   ),
+	NULL
+};
+
+static const struct hwmon_chip_info sch5627_chip_info = {
+	.ops = &sch5627_ops,
+	.info = sch5627_info,
+};
+
+static int sch5627_probe(struct platform_device *pdev)
+{
+	struct sch5627_data *data;
+	struct device *hwmon_dev;
+	int build_code, build_id, hwmon_rev, val;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(struct sch5627_data),
+			    GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->addr = platform_get_resource(pdev, IORESOURCE_IO, 0)->start;
+	mutex_init(&data->update_lock);
+	platform_set_drvdata(pdev, data);
+
+	val = sch56xx_read_virtual_reg(data->addr, SCH5627_REG_HWMON_ID);
+	if (val < 0)
+		return val;
+
+	if (val != SCH5627_HWMON_ID) {
+		pr_err("invalid %s id: 0x%02X (expected 0x%02X)\n", "hwmon",
+		       val, SCH5627_HWMON_ID);
+		return -ENODEV;
+	}
+
+	val = sch56xx_read_virtual_reg(data->addr, SCH5627_REG_COMPANY_ID);
+	if (val < 0)
+		return val;
+
+	if (val != SCH5627_COMPANY_ID) {
+		pr_err("invalid %s id: 0x%02X (expected 0x%02X)\n", "company",
+		       val, SCH5627_COMPANY_ID);
+		return -ENODEV;
+	}
+
+	val = sch56xx_read_virtual_reg(data->addr, SCH5627_REG_PRIMARY_ID);
+	if (val < 0)
+		return val;
+
+	if (val != SCH5627_PRIMARY_ID) {
+		pr_err("invalid %s id: 0x%02X (expected 0x%02X)\n", "primary",
+		       val, SCH5627_PRIMARY_ID);
+		return -ENODEV;
+	}
+
+	build_code = sch56xx_read_virtual_reg(data->addr,
+					      SCH5627_REG_BUILD_CODE);
+	if (build_code < 0)
+		return build_code;
+
+	build_id = sch56xx_read_virtual_reg16(data->addr,
+					      SCH5627_REG_BUILD_ID);
+	if (build_id < 0)
+		return build_id;
+
+	hwmon_rev = sch56xx_read_virtual_reg(data->addr,
+					     SCH5627_REG_HWMON_REV);
+	if (hwmon_rev < 0)
+		return hwmon_rev;
+
+	val = sch56xx_read_virtual_reg(data->addr, SCH5627_REG_CTRL);
+	if (val < 0)
+		return val;
+
+	data->control = val;
+	if (!(data->control & SCH5627_CTRL_START)) {
+		pr_err("hardware monitoring not enabled\n");
+		return -ENODEV;
+	}
+
+	data->regmap = devm_regmap_init_sch56xx(&pdev->dev, &data->update_lock, data->addr,
+						&sch5627_regmap_config);
+	if (IS_ERR(data->regmap))
+		return PTR_ERR(data->regmap);
+
+	/* Trigger a Vbat voltage measurement, so that we get a valid reading
+	   the first time we read Vbat */
+	sch56xx_write_virtual_reg(data->addr, SCH5627_REG_CTRL, data->control | SCH5627_CTRL_VBAT);
+	data->last_battery = jiffies;
+
+	pr_info("found %s chip at %#hx\n", DEVNAME, data->addr);
+	pr_info("firmware build: code 0x%02X, id 0x%04X, hwmon: rev 0x%02X\n",
+		build_code, build_id, hwmon_rev);
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, DEVNAME, data,
+							 &sch5627_chip_info, NULL);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	/* Note failing to register the watchdog is not a fatal error */
+	sch56xx_watchdog_register(&pdev->dev, data->addr,
+				  (build_code << 24) | (build_id << 8) | hwmon_rev,
+				  &data->update_lock, 1);
+
+	return 0;
+}
+
+static int sch5627_suspend(struct device *dev)
+{
+	struct sch5627_data *data = dev_get_drvdata(dev);
+
+	regcache_cache_only(data->regmap, true);
+	regcache_mark_dirty(data->regmap);
+
+	return 0;
+}
+
+static int sch5627_resume(struct device *dev)
+{
+	struct sch5627_data *data = dev_get_drvdata(dev);
+
+	regcache_cache_only(data->regmap, false);
+	/* We must not access the virtual registers when the lock bit is set */
+	if (data->control & SCH5627_CTRL_LOCK)
+		return regcache_drop_region(data->regmap, 0, U16_MAX);
+
+	return regcache_sync(data->regmap);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(sch5627_dev_pm_ops, sch5627_suspend, sch5627_resume);
+
+static const struct platform_device_id sch5627_device_id[] = {
+	{
+		.name = "sch5627",
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, sch5627_device_id);
+
+static struct platform_driver sch5627_driver = {
+	.driver = {
+		.name	= DRVNAME,
+		.pm	= pm_sleep_ptr(&sch5627_dev_pm_ops),
+	},
+	.probe		= sch5627_probe,
+	.id_table	= sch5627_device_id,
+};
+
+module_platform_driver(sch5627_driver);
+
+MODULE_DESCRIPTION("SMSC SCH5627 Hardware Monitoring Driver");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL");