From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/mfd/max77714.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 drivers/mfd/max77714.c (limited to 'drivers/mfd/max77714.c') diff --git a/drivers/mfd/max77714.c b/drivers/mfd/max77714.c new file mode 100644 index 000000000..c618605a3 --- /dev/null +++ b/drivers/mfd/max77714.c @@ -0,0 +1,152 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Maxim MAX77714 Core Driver + * + * Copyright (C) 2022 Luca Ceresoli + * Author: Luca Ceresoli + */ + +#include +#include +#include +#include +#include +#include +#include + +static const struct mfd_cell max77714_cells[] = { + { .name = "max77714-watchdog" }, + { .name = "max77714-rtc" }, +}; + +static const struct regmap_range max77714_readable_ranges[] = { + regmap_reg_range(MAX77714_INT_TOP, MAX77714_INT_TOP), + regmap_reg_range(MAX77714_INT_TOPM, MAX77714_INT_TOPM), + regmap_reg_range(MAX77714_32K_STATUS, MAX77714_32K_CONFIG), + regmap_reg_range(MAX77714_CNFG_GLBL2, MAX77714_CNFG2_ONOFF), +}; + +static const struct regmap_range max77714_writable_ranges[] = { + regmap_reg_range(MAX77714_INT_TOPM, MAX77714_INT_TOPM), + regmap_reg_range(MAX77714_32K_CONFIG, MAX77714_32K_CONFIG), + regmap_reg_range(MAX77714_CNFG_GLBL2, MAX77714_CNFG2_ONOFF), +}; + +static const struct regmap_access_table max77714_readable_table = { + .yes_ranges = max77714_readable_ranges, + .n_yes_ranges = ARRAY_SIZE(max77714_readable_ranges), +}; + +static const struct regmap_access_table max77714_writable_table = { + .yes_ranges = max77714_writable_ranges, + .n_yes_ranges = ARRAY_SIZE(max77714_writable_ranges), +}; + +static const struct regmap_config max77714_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = MAX77714_CNFG2_ONOFF, + .rd_table = &max77714_readable_table, + .wr_table = &max77714_writable_table, +}; + +static const struct regmap_irq max77714_top_irqs[] = { + REGMAP_IRQ_REG(MAX77714_IRQ_TOP_ONOFF, 0, MAX77714_INT_TOP_ONOFF), + REGMAP_IRQ_REG(MAX77714_IRQ_TOP_RTC, 0, MAX77714_INT_TOP_RTC), + REGMAP_IRQ_REG(MAX77714_IRQ_TOP_GPIO, 0, MAX77714_INT_TOP_GPIO), + REGMAP_IRQ_REG(MAX77714_IRQ_TOP_LDO, 0, MAX77714_INT_TOP_LDO), + REGMAP_IRQ_REG(MAX77714_IRQ_TOP_SD, 0, MAX77714_INT_TOP_SD), + REGMAP_IRQ_REG(MAX77714_IRQ_TOP_GLBL, 0, MAX77714_INT_TOP_GLBL), +}; + +static const struct regmap_irq_chip max77714_irq_chip = { + .name = "max77714-pmic", + .status_base = MAX77714_INT_TOP, + .mask_base = MAX77714_INT_TOPM, + .num_regs = 1, + .irqs = max77714_top_irqs, + .num_irqs = ARRAY_SIZE(max77714_top_irqs), +}; + +/* + * MAX77714 initially uses the internal, low precision oscillator. Enable + * the external oscillator by setting the XOSC_RETRY bit. If the external + * oscillator is not OK (probably not installed) this has no effect. + */ +static int max77714_setup_xosc(struct device *dev, struct regmap *regmap) +{ + /* Internal Crystal Load Capacitance, indexed by value of 32KLOAD bits */ + static const unsigned int load_cap[4] = {0, 10, 12, 22}; /* pF */ + unsigned int load_cap_idx; + unsigned int status; + int err; + + err = regmap_update_bits(regmap, MAX77714_32K_CONFIG, + MAX77714_32K_CONFIG_XOSC_RETRY, + MAX77714_32K_CONFIG_XOSC_RETRY); + if (err) + return dev_err_probe(dev, err, "Failed to configure the external oscillator\n"); + + err = regmap_read(regmap, MAX77714_32K_STATUS, &status); + if (err) + return dev_err_probe(dev, err, "Failed to read external oscillator status\n"); + + load_cap_idx = (status >> MAX77714_32K_STATUS_32KLOAD_SHF) + & MAX77714_32K_STATUS_32KLOAD_MSK; + + dev_info(dev, "Using %s oscillator, %d pF load cap\n", + status & MAX77714_32K_STATUS_32KSOURCE ? "internal" : "external", + load_cap[load_cap_idx]); + + return 0; +} + +static int max77714_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct regmap *regmap; + struct regmap_irq_chip_data *irq_data; + int err; + + regmap = devm_regmap_init_i2c(client, &max77714_regmap_config); + if (IS_ERR(regmap)) + return dev_err_probe(dev, PTR_ERR(regmap), + "Failed to initialise regmap\n"); + + err = max77714_setup_xosc(dev, regmap); + if (err) + return err; + + err = devm_regmap_add_irq_chip(dev, regmap, client->irq, + IRQF_ONESHOT | IRQF_SHARED, 0, + &max77714_irq_chip, &irq_data); + if (err) + return dev_err_probe(dev, err, "Failed to add PMIC IRQ chip\n"); + + err = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE, + max77714_cells, ARRAY_SIZE(max77714_cells), + NULL, 0, NULL); + if (err) + return dev_err_probe(dev, err, "Failed to register child devices\n"); + + return 0; +} + +static const struct of_device_id max77714_dt_match[] = { + { .compatible = "maxim,max77714" }, + {}, +}; +MODULE_DEVICE_TABLE(of, max77714_dt_match); + +static struct i2c_driver max77714_driver = { + .driver = { + .name = "max77714", + .of_match_table = max77714_dt_match, + }, + .probe = max77714_probe, +}; +module_i2c_driver(max77714_driver); + +MODULE_DESCRIPTION("Maxim MAX77714 MFD core driver"); +MODULE_AUTHOR("Luca Ceresoli "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1