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/reset/reset-bcm6345.c | 133 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 drivers/reset/reset-bcm6345.c (limited to 'drivers/reset/reset-bcm6345.c') diff --git a/drivers/reset/reset-bcm6345.c b/drivers/reset/reset-bcm6345.c new file mode 100644 index 000000000..441d9dd76 --- /dev/null +++ b/drivers/reset/reset-bcm6345.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * BCM6345 Reset Controller Driver + * + * Copyright (C) 2020 Álvaro Fernández Rojas + */ + +#include +#include +#include +#include +#include + +#define BCM6345_RESET_NUM 32 +#define BCM6345_RESET_SLEEP_MIN_US 10000 +#define BCM6345_RESET_SLEEP_MAX_US 20000 + +struct bcm6345_reset { + struct reset_controller_dev rcdev; + void __iomem *base; + spinlock_t lock; +}; + +static inline struct bcm6345_reset * +to_bcm6345_reset(struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct bcm6345_reset, rcdev); +} + +static int bcm6345_reset_update(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev); + unsigned long flags; + uint32_t val; + + spin_lock_irqsave(&bcm6345_reset->lock, flags); + val = __raw_readl(bcm6345_reset->base); + if (assert) + val &= ~BIT(id); + else + val |= BIT(id); + __raw_writel(val, bcm6345_reset->base); + spin_unlock_irqrestore(&bcm6345_reset->lock, flags); + + return 0; +} + +static int bcm6345_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return bcm6345_reset_update(rcdev, id, true); +} + +static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return bcm6345_reset_update(rcdev, id, false); +} + +static int bcm6345_reset_reset(struct reset_controller_dev *rcdev, + unsigned long id) +{ + bcm6345_reset_update(rcdev, id, true); + usleep_range(BCM6345_RESET_SLEEP_MIN_US, + BCM6345_RESET_SLEEP_MAX_US); + + bcm6345_reset_update(rcdev, id, false); + /* + * Ensure component is taken out reset state by sleeping also after + * deasserting the reset. Otherwise, the component may not be ready + * for operation. + */ + usleep_range(BCM6345_RESET_SLEEP_MIN_US, + BCM6345_RESET_SLEEP_MAX_US); + + return 0; +} + +static int bcm6345_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev); + + return !(__raw_readl(bcm6345_reset->base) & BIT(id)); +} + +static const struct reset_control_ops bcm6345_reset_ops = { + .assert = bcm6345_reset_assert, + .deassert = bcm6345_reset_deassert, + .reset = bcm6345_reset_reset, + .status = bcm6345_reset_status, +}; + +static int bcm6345_reset_probe(struct platform_device *pdev) +{ + struct bcm6345_reset *bcm6345_reset; + + bcm6345_reset = devm_kzalloc(&pdev->dev, + sizeof(*bcm6345_reset), GFP_KERNEL); + if (!bcm6345_reset) + return -ENOMEM; + + bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(bcm6345_reset->base)) + return PTR_ERR(bcm6345_reset->base); + + spin_lock_init(&bcm6345_reset->lock); + bcm6345_reset->rcdev.ops = &bcm6345_reset_ops; + bcm6345_reset->rcdev.owner = THIS_MODULE; + bcm6345_reset->rcdev.of_node = pdev->dev.of_node; + bcm6345_reset->rcdev.of_reset_n_cells = 1; + bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM; + + return devm_reset_controller_register(&pdev->dev, + &bcm6345_reset->rcdev); +} + +static const struct of_device_id bcm6345_reset_of_match[] = { + { .compatible = "brcm,bcm6345-reset" }, + { .compatible = "brcm,bcm63xx-ephy-ctrl" }, + { /* sentinel */ }, +}; + +static struct platform_driver bcm6345_reset_driver = { + .probe = bcm6345_reset_probe, + .driver = { + .name = "bcm6345-reset", + .of_match_table = bcm6345_reset_of_match, + .suppress_bind_attrs = true, + }, +}; +builtin_platform_driver(bcm6345_reset_driver); -- cgit v1.3.1