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-brcmstb.c | 126 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 126 insertions(+) create mode 100644 drivers/reset/reset-brcmstb.c (limited to 'drivers/reset/reset-brcmstb.c') diff --git a/drivers/reset/reset-brcmstb.c b/drivers/reset/reset-brcmstb.c new file mode 100644 index 000000000..810fe7645 --- /dev/null +++ b/drivers/reset/reset-brcmstb.c @@ -0,0 +1,126 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Broadcom STB generic reset controller for SW_INIT style reset controller + * + * Author: Florian Fainelli + * Copyright (C) 2018 Broadcom + */ +#include +#include +#include +#include +#include +#include +#include +#include + +struct brcmstb_reset { + void __iomem *base; + struct reset_controller_dev rcdev; +}; + +#define SW_INIT_SET 0x00 +#define SW_INIT_CLEAR 0x04 +#define SW_INIT_STATUS 0x08 + +#define SW_INIT_BIT(id) BIT((id) & 0x1f) +#define SW_INIT_BANK(id) ((id) >> 5) + +/* A full bank contains extra registers that we are not utilizing but still + * qualify as a single bank. + */ +#define SW_INIT_BANK_SIZE 0x18 + +static inline +struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct brcmstb_reset, rcdev); +} + +static int brcmstb_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; + struct brcmstb_reset *priv = to_brcmstb(rcdev); + + writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET); + + return 0; +} + +static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; + struct brcmstb_reset *priv = to_brcmstb(rcdev); + + writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR); + /* Maximum reset delay after de-asserting a line and seeing block + * operation is typically 14us for the worst case, build some slack + * here. + */ + usleep_range(100, 200); + + return 0; +} + +static int brcmstb_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; + struct brcmstb_reset *priv = to_brcmstb(rcdev); + + return readl_relaxed(priv->base + off + SW_INIT_STATUS) & + SW_INIT_BIT(id); +} + +static const struct reset_control_ops brcmstb_reset_ops = { + .assert = brcmstb_reset_assert, + .deassert = brcmstb_reset_deassert, + .status = brcmstb_reset_status, +}; + +static int brcmstb_reset_probe(struct platform_device *pdev) +{ + struct device *kdev = &pdev->dev; + struct brcmstb_reset *priv; + struct resource *res; + + priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + dev_set_drvdata(kdev, priv); + + priv->rcdev.owner = THIS_MODULE; + priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res), + SW_INIT_BANK_SIZE) * 32; + priv->rcdev.ops = &brcmstb_reset_ops; + priv->rcdev.of_node = kdev->of_node; + /* Use defaults: 1 cell and simple xlate function */ + + return devm_reset_controller_register(kdev, &priv->rcdev); +} + +static const struct of_device_id brcmstb_reset_of_match[] = { + { .compatible = "brcm,brcmstb-reset" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, brcmstb_reset_of_match); + +static struct platform_driver brcmstb_reset_driver = { + .probe = brcmstb_reset_probe, + .driver = { + .name = "brcmstb-reset", + .of_match_table = brcmstb_reset_of_match, + }, +}; +module_platform_driver(brcmstb_reset_driver); + +MODULE_AUTHOR("Broadcom"); +MODULE_DESCRIPTION("Broadcom STB reset controller"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1