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/misc/tps6594-esm.c | 146 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) create mode 100644 drivers/misc/tps6594-esm.c (limited to 'drivers/misc/tps6594-esm.c') diff --git a/drivers/misc/tps6594-esm.c b/drivers/misc/tps6594-esm.c new file mode 100644 index 000000000..50e121669 --- /dev/null +++ b/drivers/misc/tps6594-esm.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * ESM (Error Signal Monitor) driver for TI TPS6594/TPS6593/LP8764 PMICs + * + * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/ + */ + +#include +#include +#include +#include +#include + +#include + +#define TPS6594_DEV_REV_1 0x08 + +static irqreturn_t tps6594_esm_isr(int irq, void *dev_id) +{ + struct platform_device *pdev = dev_id; + int i; + + for (i = 0 ; i < pdev->num_resources ; i++) { + if (irq == platform_get_irq_byname(pdev, pdev->resource[i].name)) { + dev_err(pdev->dev.parent, "%s error detected\n", pdev->resource[i].name); + return IRQ_HANDLED; + } + } + + return IRQ_NONE; +} + +static int tps6594_esm_probe(struct platform_device *pdev) +{ + struct tps6594 *tps = dev_get_drvdata(pdev->dev.parent); + struct device *dev = &pdev->dev; + unsigned int rev; + int irq; + int ret; + int i; + + /* + * Due to a bug in revision 1 of the PMIC, the GPIO3 used for the + * SoC ESM function is used to power the load switch instead. + * As a consequence, ESM can not be used on those PMIC. + * Check the version and return an error in case of revision 1. + */ + ret = regmap_read(tps->regmap, TPS6594_REG_DEV_REV, &rev); + if (ret) + return dev_err_probe(dev, ret, + "Failed to read PMIC revision\n"); + if (rev == TPS6594_DEV_REV_1) + return dev_err_probe(dev, -ENODEV, + "ESM not supported for revision 1 PMIC\n"); + + for (i = 0; i < pdev->num_resources; i++) { + irq = platform_get_irq_byname(pdev, pdev->resource[i].name); + if (irq < 0) + return irq; + + ret = devm_request_threaded_irq(dev, irq, NULL, + tps6594_esm_isr, IRQF_ONESHOT, + pdev->resource[i].name, pdev); + if (ret) + return ret; + } + + ret = regmap_set_bits(tps->regmap, TPS6594_REG_ESM_SOC_MODE_CFG, + TPS6594_BIT_ESM_SOC_EN | TPS6594_BIT_ESM_SOC_ENDRV); + if (ret) + return dev_err_probe(dev, ret, "Failed to configure ESM\n"); + + ret = regmap_set_bits(tps->regmap, TPS6594_REG_ESM_SOC_START_REG, + TPS6594_BIT_ESM_SOC_START); + if (ret) + return dev_err_probe(dev, ret, "Failed to start ESM\n"); + + pm_runtime_enable(dev); + pm_runtime_get_sync(dev); + + return 0; +} + +static void tps6594_esm_remove(struct platform_device *pdev) +{ + struct tps6594 *tps = dev_get_drvdata(pdev->dev.parent); + struct device *dev = &pdev->dev; + int ret; + + ret = regmap_clear_bits(tps->regmap, TPS6594_REG_ESM_SOC_START_REG, + TPS6594_BIT_ESM_SOC_START); + if (ret) { + dev_err(dev, "Failed to stop ESM\n"); + goto out; + } + + ret = regmap_clear_bits(tps->regmap, TPS6594_REG_ESM_SOC_MODE_CFG, + TPS6594_BIT_ESM_SOC_EN | TPS6594_BIT_ESM_SOC_ENDRV); + if (ret) + dev_err(dev, "Failed to unconfigure ESM\n"); + +out: + pm_runtime_put_sync(dev); + pm_runtime_disable(dev); +} + +static int tps6594_esm_suspend(struct device *dev) +{ + struct tps6594 *tps = dev_get_drvdata(dev->parent); + int ret; + + ret = regmap_clear_bits(tps->regmap, TPS6594_REG_ESM_SOC_START_REG, + TPS6594_BIT_ESM_SOC_START); + + pm_runtime_put_sync(dev); + + return ret; +} + +static int tps6594_esm_resume(struct device *dev) +{ + struct tps6594 *tps = dev_get_drvdata(dev->parent); + + pm_runtime_get_sync(dev); + + return regmap_set_bits(tps->regmap, TPS6594_REG_ESM_SOC_START_REG, + TPS6594_BIT_ESM_SOC_START); +} + +static DEFINE_SIMPLE_DEV_PM_OPS(tps6594_esm_pm_ops, tps6594_esm_suspend, tps6594_esm_resume); + +static struct platform_driver tps6594_esm_driver = { + .driver = { + .name = "tps6594-esm", + .pm = pm_sleep_ptr(&tps6594_esm_pm_ops), + }, + .probe = tps6594_esm_probe, + .remove = tps6594_esm_remove, +}; + +module_platform_driver(tps6594_esm_driver); + +MODULE_ALIAS("platform:tps6594-esm"); +MODULE_AUTHOR("Julien Panis "); +MODULE_DESCRIPTION("TPS6594 Error Signal Monitor Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1