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/mfd/max77650.c | 231 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 231 insertions(+) create mode 100644 drivers/mfd/max77650.c (limited to 'drivers/mfd/max77650.c') diff --git a/drivers/mfd/max77650.c b/drivers/mfd/max77650.c new file mode 100644 index 000000000..75b5dc44e --- /dev/null +++ b/drivers/mfd/max77650.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Copyright (C) 2018 BayLibre SAS +// Author: Bartosz Golaszewski +// +// Core MFD driver for MAXIM 77650/77651 charger/power-supply. +// Programming manual: https://pdfserv.maximintegrated.com/en/an/AN6428.pdf + +#include +#include +#include +#include +#include +#include +#include +#include + +#define MAX77650_INT_GPI_F_MSK BIT(0) +#define MAX77650_INT_GPI_R_MSK BIT(1) +#define MAX77650_INT_GPI_MSK \ + (MAX77650_INT_GPI_F_MSK | MAX77650_INT_GPI_R_MSK) +#define MAX77650_INT_nEN_F_MSK BIT(2) +#define MAX77650_INT_nEN_R_MSK BIT(3) +#define MAX77650_INT_TJAL1_R_MSK BIT(4) +#define MAX77650_INT_TJAL2_R_MSK BIT(5) +#define MAX77650_INT_DOD_R_MSK BIT(6) + +#define MAX77650_INT_THM_MSK BIT(0) +#define MAX77650_INT_CHG_MSK BIT(1) +#define MAX77650_INT_CHGIN_MSK BIT(2) +#define MAX77650_INT_TJ_REG_MSK BIT(3) +#define MAX77650_INT_CHGIN_CTRL_MSK BIT(4) +#define MAX77650_INT_SYS_CTRL_MSK BIT(5) +#define MAX77650_INT_SYS_CNFG_MSK BIT(6) + +#define MAX77650_INT_GLBL_OFFSET 0 +#define MAX77650_INT_CHG_OFFSET 1 + +#define MAX77650_SBIA_LPM_MASK BIT(5) +#define MAX77650_SBIA_LPM_DISABLED 0x00 + +enum { + MAX77650_INT_GPI, + MAX77650_INT_nEN_F, + MAX77650_INT_nEN_R, + MAX77650_INT_TJAL1_R, + MAX77650_INT_TJAL2_R, + MAX77650_INT_DOD_R, + MAX77650_INT_THM, + MAX77650_INT_CHG, + MAX77650_INT_CHGIN, + MAX77650_INT_TJ_REG, + MAX77650_INT_CHGIN_CTRL, + MAX77650_INT_SYS_CTRL, + MAX77650_INT_SYS_CNFG, +}; + +static const struct resource max77650_charger_resources[] = { + DEFINE_RES_IRQ_NAMED(MAX77650_INT_CHG, "CHG"), + DEFINE_RES_IRQ_NAMED(MAX77650_INT_CHGIN, "CHGIN"), +}; + +static const struct resource max77650_gpio_resources[] = { + DEFINE_RES_IRQ_NAMED(MAX77650_INT_GPI, "GPI"), +}; + +static const struct resource max77650_onkey_resources[] = { + DEFINE_RES_IRQ_NAMED(MAX77650_INT_nEN_F, "nEN_F"), + DEFINE_RES_IRQ_NAMED(MAX77650_INT_nEN_R, "nEN_R"), +}; + +static const struct mfd_cell max77650_cells[] = { + { + .name = "max77650-regulator", + .of_compatible = "maxim,max77650-regulator", + }, { + .name = "max77650-charger", + .of_compatible = "maxim,max77650-charger", + .resources = max77650_charger_resources, + .num_resources = ARRAY_SIZE(max77650_charger_resources), + }, { + .name = "max77650-gpio", + .of_compatible = "maxim,max77650-gpio", + .resources = max77650_gpio_resources, + .num_resources = ARRAY_SIZE(max77650_gpio_resources), + }, { + .name = "max77650-led", + .of_compatible = "maxim,max77650-led", + }, { + .name = "max77650-onkey", + .of_compatible = "maxim,max77650-onkey", + .resources = max77650_onkey_resources, + .num_resources = ARRAY_SIZE(max77650_onkey_resources), + }, +}; + +static const struct regmap_irq max77650_irqs[] = { + [MAX77650_INT_GPI] = { + .reg_offset = MAX77650_INT_GLBL_OFFSET, + .mask = MAX77650_INT_GPI_MSK, + .type = { + .type_falling_val = MAX77650_INT_GPI_F_MSK, + .type_rising_val = MAX77650_INT_GPI_R_MSK, + .types_supported = IRQ_TYPE_EDGE_BOTH, + }, + }, + REGMAP_IRQ_REG(MAX77650_INT_nEN_F, + MAX77650_INT_GLBL_OFFSET, MAX77650_INT_nEN_F_MSK), + REGMAP_IRQ_REG(MAX77650_INT_nEN_R, + MAX77650_INT_GLBL_OFFSET, MAX77650_INT_nEN_R_MSK), + REGMAP_IRQ_REG(MAX77650_INT_TJAL1_R, + MAX77650_INT_GLBL_OFFSET, MAX77650_INT_TJAL1_R_MSK), + REGMAP_IRQ_REG(MAX77650_INT_TJAL2_R, + MAX77650_INT_GLBL_OFFSET, MAX77650_INT_TJAL2_R_MSK), + REGMAP_IRQ_REG(MAX77650_INT_DOD_R, + MAX77650_INT_GLBL_OFFSET, MAX77650_INT_DOD_R_MSK), + REGMAP_IRQ_REG(MAX77650_INT_THM, + MAX77650_INT_CHG_OFFSET, MAX77650_INT_THM_MSK), + REGMAP_IRQ_REG(MAX77650_INT_CHG, + MAX77650_INT_CHG_OFFSET, MAX77650_INT_CHG_MSK), + REGMAP_IRQ_REG(MAX77650_INT_CHGIN, + MAX77650_INT_CHG_OFFSET, MAX77650_INT_CHGIN_MSK), + REGMAP_IRQ_REG(MAX77650_INT_TJ_REG, + MAX77650_INT_CHG_OFFSET, MAX77650_INT_TJ_REG_MSK), + REGMAP_IRQ_REG(MAX77650_INT_CHGIN_CTRL, + MAX77650_INT_CHG_OFFSET, MAX77650_INT_CHGIN_CTRL_MSK), + REGMAP_IRQ_REG(MAX77650_INT_SYS_CTRL, + MAX77650_INT_CHG_OFFSET, MAX77650_INT_SYS_CTRL_MSK), + REGMAP_IRQ_REG(MAX77650_INT_SYS_CNFG, + MAX77650_INT_CHG_OFFSET, MAX77650_INT_SYS_CNFG_MSK), +}; + +static const struct regmap_irq_chip max77650_irq_chip = { + .name = "max77650-irq", + .irqs = max77650_irqs, + .num_irqs = ARRAY_SIZE(max77650_irqs), + .num_regs = 2, + .status_base = MAX77650_REG_INT_GLBL, + .mask_base = MAX77650_REG_INTM_GLBL, + .type_in_mask = true, + .init_ack_masked = true, + .clear_on_unmask = true, +}; + +static const struct regmap_config max77650_regmap_config = { + .name = "max77650", + .reg_bits = 8, + .val_bits = 8, +}; + +static int max77650_i2c_probe(struct i2c_client *i2c) +{ + struct regmap_irq_chip_data *irq_data; + struct device *dev = &i2c->dev; + struct irq_domain *domain; + struct regmap *map; + unsigned int val; + int rv, id; + + map = devm_regmap_init_i2c(i2c, &max77650_regmap_config); + if (IS_ERR(map)) { + dev_err(dev, "Unable to initialise I2C Regmap\n"); + return PTR_ERR(map); + } + + rv = regmap_read(map, MAX77650_REG_CID, &val); + if (rv) { + dev_err(dev, "Unable to read Chip ID\n"); + return rv; + } + + id = MAX77650_CID_BITS(val); + switch (id) { + case MAX77650_CID_77650A: + case MAX77650_CID_77650C: + case MAX77650_CID_77651A: + case MAX77650_CID_77651B: + break; + default: + dev_err(dev, "Chip not supported - ID: 0x%02x\n", id); + return -ENODEV; + } + + /* + * This IC has a low-power mode which reduces the quiescent current + * consumption to ~5.6uA but is only suitable for systems consuming + * less than ~2mA. Since this is not likely the case even on + * linux-based wearables - keep the chip in normal power mode. + */ + rv = regmap_update_bits(map, + MAX77650_REG_CNFG_GLBL, + MAX77650_SBIA_LPM_MASK, + MAX77650_SBIA_LPM_DISABLED); + if (rv) { + dev_err(dev, "Unable to change the power mode\n"); + return rv; + } + + rv = devm_regmap_add_irq_chip(dev, map, i2c->irq, + IRQF_ONESHOT | IRQF_SHARED, 0, + &max77650_irq_chip, &irq_data); + if (rv) { + dev_err(dev, "Unable to add Regmap IRQ chip\n"); + return rv; + } + + domain = regmap_irq_get_domain(irq_data); + + return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE, + max77650_cells, ARRAY_SIZE(max77650_cells), + NULL, 0, domain); +} + +static const struct of_device_id max77650_of_match[] = { + { .compatible = "maxim,max77650" }, + { } +}; +MODULE_DEVICE_TABLE(of, max77650_of_match); + +static struct i2c_driver max77650_i2c_driver = { + .driver = { + .name = "max77650", + .of_match_table = max77650_of_match, + }, + .probe = max77650_i2c_probe, +}; +module_i2c_driver(max77650_i2c_driver); + +MODULE_DESCRIPTION("MAXIM 77650/77651 multi-function core driver"); +MODULE_AUTHOR("Bartosz Golaszewski "); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1