From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions 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) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/regulator/mp8859.c | 408 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 408 insertions(+) create mode 100644 drivers/regulator/mp8859.c (limited to 'drivers/regulator/mp8859.c') diff --git a/drivers/regulator/mp8859.c b/drivers/regulator/mp8859.c new file mode 100644 index 000000000..9a708e826 --- /dev/null +++ b/drivers/regulator/mp8859.c @@ -0,0 +1,408 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Copyright (c) 2019 five technologies GmbH +// Author: Markus Reichl + +#include +#include +#include +#include +#include + + +#define VOL_MIN_IDX 0x00 +#define VOL_MAX_IDX 0x7ff + +/* Register definitions */ +#define MP8859_VOUT_L_REG 0 //3 lo Bits +#define MP8859_VOUT_H_REG 1 //8 hi Bits +#define MP8859_VOUT_GO_REG 2 +#define MP8859_IOUT_LIM_REG 3 +#define MP8859_CTL1_REG 4 +#define MP8859_CTL2_REG 5 +#define MP8859_RESERVED1_REG 6 +#define MP8859_RESERVED2_REG 7 +#define MP8859_RESERVED3_REG 8 +#define MP8859_STATUS_REG 9 +#define MP8859_INTERRUPT_REG 0x0A +#define MP8859_MASK_REG 0x0B +#define MP8859_ID1_REG 0x0C +#define MP8859_MFR_ID_REG 0x27 +#define MP8859_DEV_ID_REG 0x28 +#define MP8859_IC_REV_REG 0x29 + +#define MP8859_MAX_REG 0x29 + +#define MP8859_GO_BIT 0x01 + +#define MP8859_IOUT_LIM_MASK 0x7f + +#define MP8859_ENABLE_MASK 0x80 +#define MP8859_DISCHG_EN_MASK 0x10 +#define MP8859_MODE_MASK 0x08 + +#define MP8859_PG_MASK 0x80 +#define MP8859_OTP_MASK 0x40 +#define MP8859_OTW_MASK 0x20 +#define MP8859_CC_CV_MASK 0x10 + +static int mp8859_set_voltage_sel(struct regulator_dev *rdev, unsigned int sel) +{ + int ret; + + ret = regmap_write(rdev->regmap, MP8859_VOUT_L_REG, sel & 0x7); + + if (ret) + return ret; + ret = regmap_write(rdev->regmap, MP8859_VOUT_H_REG, sel >> 3); + + if (ret) + return ret; + ret = regmap_update_bits(rdev->regmap, MP8859_VOUT_GO_REG, + MP8859_GO_BIT, 1); + return ret; +} + +static int mp8859_get_voltage_sel(struct regulator_dev *rdev) +{ + unsigned int val_tmp; + unsigned int val; + int ret; + + ret = regmap_read(rdev->regmap, MP8859_VOUT_H_REG, &val_tmp); + + if (ret) + return ret; + val = val_tmp << 3; + + ret = regmap_read(rdev->regmap, MP8859_VOUT_L_REG, &val_tmp); + + if (ret) + return ret; + val |= val_tmp & 0x07; + return val; +} + +static int mp8859_set_voltage_time_sel(struct regulator_dev *rdev, + unsigned int from, unsigned int to) +{ + int change; + + /* The voltage ramps at 1mV/uS, selectors are 10mV */ + if (from > to) + change = from - to; + else + change = to - from; + + return change * 10 * 1000; +} + +static unsigned int mp8859_get_mode(struct regulator_dev *rdev) +{ + unsigned int val; + int ret; + + ret = regmap_read(rdev->regmap, MP8859_CTL1_REG, &val); + if (ret != 0) { + dev_err(&rdev->dev, "Failed to read mode: %d\n", ret); + return 0; + } + + if (val & MP8859_MODE_MASK) + return REGULATOR_MODE_FAST; + else + return REGULATOR_MODE_NORMAL; +} + +static int mp8859_set_mode(struct regulator_dev *rdev, unsigned int mode) +{ + unsigned int val; + + switch (mode) { + case REGULATOR_MODE_FAST: + val = MP8859_MODE_MASK; + break; + case REGULATOR_MODE_NORMAL: + val = 0; + break; + default: + return -EINVAL; + } + + return regmap_update_bits(rdev->regmap, MP8859_CTL1_REG, + MP8859_MODE_MASK, val); +} + +static int mp8859_set_current_limit(struct regulator_dev *rdev, + int min_uA, int max_uA) +{ + unsigned int cur_val, new_val; + int ret, i; + + /* Steps of 50mA */ + new_val = max_uA / 50000; + if (new_val > MP8859_IOUT_LIM_MASK) + return -EINVAL; + if (new_val == 0) + return -EINVAL; + + /* + * If the regulator is limiting then ramp gradually as per + * datasheet, otherwise just set the value directly. + */ + ret = regmap_read(rdev->regmap, MP8859_STATUS_REG, &cur_val); + if (ret != 0) + return ret; + if (!(cur_val & MP8859_CC_CV_MASK)) { + return regmap_update_bits(rdev->regmap, MP8859_IOUT_LIM_REG, + MP8859_IOUT_LIM_MASK, new_val); + } + + ret = regmap_read(rdev->regmap, MP8859_IOUT_LIM_REG, &cur_val); + if (ret != 0) + return ret; + + if (cur_val >= new_val) { + for (i = cur_val; i >= new_val; i--) { + ret = regmap_update_bits(rdev->regmap, + MP8859_IOUT_LIM_REG, + MP8859_IOUT_LIM_MASK, + cur_val - i); + if (ret != 0) + return ret; + } + } else { + for (i = cur_val; i <= new_val; i++) { + ret = regmap_update_bits(rdev->regmap, + MP8859_IOUT_LIM_REG, + MP8859_IOUT_LIM_MASK, + cur_val + i); + if (ret != 0) + return ret; + } + } + + return 0; +} + +static int mp8859_get_status(struct regulator_dev *rdev) +{ + unsigned int val; + int ret; + + /* Output status is only meaingful when enabled */ + ret = regmap_read(rdev->regmap, MP8859_CTL1_REG, &val); + if (ret != 0) + return ret; + if (!(val & MP8859_ENABLE_MASK)) + return REGULATOR_STATUS_UNDEFINED; + + ret = regmap_read(rdev->regmap, MP8859_STATUS_REG, &val); + if (ret != 0) + return ret; + + if (val & MP8859_PG_MASK) + return REGULATOR_STATUS_ON; + else + return REGULATOR_STATUS_ERROR; +} + +static int mp8859_get_error_flags(struct regulator_dev *rdev, + unsigned int *flags) +{ + unsigned int status, enabled; + int ret; + + *flags = 0; + + /* Output status is only meaingful when enabled */ + ret = regmap_read(rdev->regmap, MP8859_CTL1_REG, &enabled); + if (ret != 0) + return ret; + enabled &= MP8859_ENABLE_MASK; + + ret = regmap_read(rdev->regmap, MP8859_STATUS_REG, &status); + if (ret != 0) + return ret; + + if (enabled && !(status & MP8859_PG_MASK)) + status |= REGULATOR_ERROR_FAIL; + if (status & MP8859_OTP_MASK) + status |= REGULATOR_ERROR_OVER_TEMP; + if (status & MP8859_OTW_MASK) + status |= REGULATOR_ERROR_OVER_TEMP_WARN; + if (status & MP8859_CC_CV_MASK) + status |= REGULATOR_ERROR_OVER_CURRENT; + + return 0; +} + +static const struct linear_range mp8859_dcdc_ranges[] = { + REGULATOR_LINEAR_RANGE(0, VOL_MIN_IDX, VOL_MAX_IDX, 10000), +}; + +static bool mp8859_readable(struct device *dev, unsigned int reg) +{ + switch (reg) { + case MP8859_VOUT_L_REG: + case MP8859_VOUT_H_REG: + case MP8859_VOUT_GO_REG: + case MP8859_IOUT_LIM_REG: + case MP8859_CTL1_REG: + case MP8859_CTL2_REG: + case MP8859_STATUS_REG: + case MP8859_INTERRUPT_REG: + case MP8859_MASK_REG: + case MP8859_ID1_REG: + case MP8859_MFR_ID_REG: + case MP8859_DEV_ID_REG: + case MP8859_IC_REV_REG: + return true; + default: + return false; + } +} + +static bool mp8859_volatile(struct device *dev, unsigned int reg) +{ + switch (reg) { + case MP8859_VOUT_GO_REG: + case MP8859_STATUS_REG: + case MP8859_INTERRUPT_REG: + return true; + default: + return false; + } +} + +static const struct regmap_config mp8859_regmap = { + .reg_bits = 8, + .val_bits = 8, + .max_register = MP8859_MAX_REG, + .cache_type = REGCACHE_MAPLE, + .readable_reg = mp8859_readable, + .volatile_reg = mp8859_volatile, +}; + +static const struct regulator_ops mp8859_ops = { + .set_voltage_sel = mp8859_set_voltage_sel, + .get_voltage_sel = mp8859_get_voltage_sel, + .list_voltage = regulator_list_voltage_linear_range, + .set_voltage_time_sel = mp8859_set_voltage_time_sel, + .enable = regulator_enable_regmap, + .disable = regulator_disable_regmap, + .is_enabled = regulator_is_enabled_regmap, + .set_mode = mp8859_set_mode, + .get_mode = mp8859_get_mode, + .set_active_discharge = regulator_set_active_discharge_regmap, + .set_current_limit = mp8859_set_current_limit, + .get_status = mp8859_get_status, + .get_error_flags = mp8859_get_error_flags, +}; + +static const struct regulator_desc mp8859_regulators[] = { + { + .id = 0, + .type = REGULATOR_VOLTAGE, + .name = "mp8859_dcdc", + .supply_name = "vin", + .of_match = of_match_ptr("mp8859_dcdc"), + .n_voltages = VOL_MAX_IDX + 1, + .linear_ranges = mp8859_dcdc_ranges, + .n_linear_ranges = 1, + .enable_reg = MP8859_CTL1_REG, + .enable_mask = MP8859_ENABLE_MASK, + .enable_val = MP8859_ENABLE_MASK, + .active_discharge_reg = MP8859_CTL1_REG, + .active_discharge_on = MP8859_DISCHG_EN_MASK, + .active_discharge_mask = MP8859_DISCHG_EN_MASK, + .ops = &mp8859_ops, + .owner = THIS_MODULE, + }, +}; + +static int mp8859_i2c_probe(struct i2c_client *i2c) +{ + int ret; + struct regulator_config config = {.dev = &i2c->dev}; + struct regmap *regmap = devm_regmap_init_i2c(i2c, &mp8859_regmap); + struct regulator_dev *rdev; + unsigned int val, rev; + + if (IS_ERR(regmap)) { + ret = PTR_ERR(regmap); + dev_err(&i2c->dev, "regmap init failed: %d\n", ret); + return ret; + } + + ret = regmap_read(regmap, MP8859_MFR_ID_REG, &val); + if (ret != 0) { + dev_err(&i2c->dev, "Failed to read manufacturer ID: %d\n", ret); + return ret; + } + if (val != 0x9) { + dev_err(&i2c->dev, "Manufacturer ID %x != 9\n", val); + return -EINVAL; + } + + ret = regmap_read(regmap, MP8859_DEV_ID_REG, &val); + if (ret != 0) { + dev_err(&i2c->dev, "Failed to read device ID: %d\n", ret); + return ret; + } + if (val != 0x58) { + dev_err(&i2c->dev, "Manufacturer ID %x != 0x58\n", val); + return -EINVAL; + } + + ret = regmap_read(regmap, MP8859_IC_REV_REG, &rev); + if (ret != 0) { + dev_err(&i2c->dev, "Failed to read device revision: %d\n", ret); + return ret; + } + ret = regmap_read(regmap, MP8859_ID1_REG, &val); + if (ret != 0) { + dev_err(&i2c->dev, "Failed to read device ID1: %d\n", ret); + return ret; + } + dev_info(&i2c->dev, "MP8859-%04d revision %d\n", val, rev); + + rdev = devm_regulator_register(&i2c->dev, &mp8859_regulators[0], + &config); + + if (IS_ERR(rdev)) { + ret = PTR_ERR(rdev); + dev_err(&i2c->dev, "failed to register %s: %d\n", + mp8859_regulators[0].name, ret); + return ret; + } + return 0; +} + +static const struct of_device_id mp8859_dt_id[] __maybe_unused = { + {.compatible = "mps,mp8859"}, + {}, +}; +MODULE_DEVICE_TABLE(of, mp8859_dt_id); + +static const struct i2c_device_id mp8859_i2c_id[] = { + { .name = "mp8859" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, mp8859_i2c_id); + +static struct i2c_driver mp8859_regulator_driver = { + .driver = { + .name = "mp8859", + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + .of_match_table = of_match_ptr(mp8859_dt_id), + }, + .probe = mp8859_i2c_probe, + .id_table = mp8859_i2c_id, +}; + +module_i2c_driver(mp8859_regulator_driver); + +MODULE_DESCRIPTION("Monolithic Power Systems MP8859 voltage regulator driver"); +MODULE_AUTHOR("Markus Reichl "); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1