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/ab8500-sysctrl.c | 169 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 drivers/mfd/ab8500-sysctrl.c (limited to 'drivers/mfd/ab8500-sysctrl.c') diff --git a/drivers/mfd/ab8500-sysctrl.c b/drivers/mfd/ab8500-sysctrl.c new file mode 100644 index 000000000..b6b44e2e3 --- /dev/null +++ b/drivers/mfd/ab8500-sysctrl.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AB8500 system control driver + * + * Copyright (C) ST-Ericsson SA 2010 + * Author: Mattias Nilsson for ST Ericsson. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* RtcCtrl bits */ +#define AB8500_ALARM_MIN_LOW 0x08 +#define AB8500_ALARM_MIN_MID 0x09 +#define RTC_CTRL 0x0B +#define RTC_ALARM_ENABLE 0x4 + +static struct device *sysctrl_dev; + +static void ab8500_power_off(void) +{ + sigset_t old; + sigset_t all; + static const char * const pss[] = {"ab8500_ac", "ab8500_usb"}; + int i; + bool charger_present = false; + union power_supply_propval val; + struct power_supply *psy; + int ret; + + if (sysctrl_dev == NULL) { + pr_err("%s: sysctrl not initialized\n", __func__); + return; + } + + /* + * If we have a charger connected and we're powering off, + * reboot into charge-only mode. + */ + + for (i = 0; i < ARRAY_SIZE(pss); i++) { + psy = power_supply_get_by_name(pss[i]); + if (!psy) + continue; + + ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_ONLINE, + &val); + power_supply_put(psy); + + if (!ret && val.intval) { + charger_present = true; + break; + } + } + + if (!charger_present) + goto shutdown; + + /* Check if battery is known */ + psy = power_supply_get_by_name("ab8500_btemp"); + if (psy) { + ret = power_supply_get_property(psy, + POWER_SUPPLY_PROP_TECHNOLOGY, &val); + if (!ret && val.intval != POWER_SUPPLY_TECHNOLOGY_UNKNOWN) { + pr_info("Charger '%s' is connected with known battery", + pss[i]); + pr_info(" - Rebooting.\n"); + machine_restart("charging"); + } + power_supply_put(psy); + } + +shutdown: + sigfillset(&all); + + if (!sigprocmask(SIG_BLOCK, &all, &old)) { + (void)ab8500_sysctrl_set(AB8500_STW4500CTRL1, + AB8500_STW4500CTRL1_SWOFF | + AB8500_STW4500CTRL1_SWRESET4500N); + (void)sigprocmask(SIG_SETMASK, &old, NULL); + } +} + +static inline bool valid_bank(u8 bank) +{ + return ((bank == AB8500_SYS_CTRL1_BLOCK) || + (bank == AB8500_SYS_CTRL2_BLOCK)); +} + +int ab8500_sysctrl_read(u16 reg, u8 *value) +{ + u8 bank; + + if (sysctrl_dev == NULL) + return -EPROBE_DEFER; + + bank = (reg >> 8); + if (!valid_bank(bank)) + return -EINVAL; + + return abx500_get_register_interruptible(sysctrl_dev, bank, + (u8)(reg & 0xFF), value); +} +EXPORT_SYMBOL(ab8500_sysctrl_read); + +int ab8500_sysctrl_write(u16 reg, u8 mask, u8 value) +{ + u8 bank; + + if (sysctrl_dev == NULL) + return -EPROBE_DEFER; + + bank = (reg >> 8); + if (!valid_bank(bank)) { + pr_err("invalid bank\n"); + return -EINVAL; + } + + return abx500_mask_and_set_register_interruptible(sysctrl_dev, bank, + (u8)(reg & 0xFF), mask, value); +} +EXPORT_SYMBOL(ab8500_sysctrl_write); + +static int ab8500_sysctrl_probe(struct platform_device *pdev) +{ + sysctrl_dev = &pdev->dev; + + if (!pm_power_off) + pm_power_off = ab8500_power_off; + + return 0; +} + +static void ab8500_sysctrl_remove(struct platform_device *pdev) +{ + sysctrl_dev = NULL; + + if (pm_power_off == ab8500_power_off) + pm_power_off = NULL; +} + +static const struct of_device_id ab8500_sysctrl_match[] = { + { .compatible = "stericsson,ab8500-sysctrl", }, + {} +}; + +static struct platform_driver ab8500_sysctrl_driver = { + .driver = { + .name = "ab8500-sysctrl", + .of_match_table = ab8500_sysctrl_match, + }, + .probe = ab8500_sysctrl_probe, + .remove = ab8500_sysctrl_remove, +}; + +static int __init ab8500_sysctrl_init(void) +{ + return platform_driver_register(&ab8500_sysctrl_driver); +} +arch_initcall(ab8500_sysctrl_init); -- cgit v1.3.1