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-berlin.c | 111 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 drivers/reset/reset-berlin.c (limited to 'drivers/reset/reset-berlin.c') diff --git a/drivers/reset/reset-berlin.c b/drivers/reset/reset-berlin.c new file mode 100644 index 000000000..578fe8670 --- /dev/null +++ b/drivers/reset/reset-berlin.c @@ -0,0 +1,111 @@ +/* + * Copyright (C) 2014 Marvell Technology Group Ltd. + * + * Marvell Berlin reset driver + * + * Antoine Tenart + * Sebastian Hesselbarth + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define BERLIN_MAX_RESETS 32 + +#define to_berlin_reset_priv(p) \ + container_of((p), struct berlin_reset_priv, rcdev) + +struct berlin_reset_priv { + struct regmap *regmap; + struct reset_controller_dev rcdev; +}; + +static int berlin_reset_reset(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev); + int offset = id >> 8; + int mask = BIT(id & 0x1f); + + regmap_write(priv->regmap, offset, mask); + + /* let the reset be effective */ + udelay(10); + + return 0; +} + +static const struct reset_control_ops berlin_reset_ops = { + .reset = berlin_reset_reset, +}; + +static int berlin_reset_xlate(struct reset_controller_dev *rcdev, + const struct of_phandle_args *reset_spec) +{ + unsigned int offset, bit; + + offset = reset_spec->args[0]; + bit = reset_spec->args[1]; + + if (bit >= BERLIN_MAX_RESETS) + return -EINVAL; + + return (offset << 8) | bit; +} + +static int berlin2_reset_probe(struct platform_device *pdev) +{ + struct device_node *parent_np; + struct berlin_reset_priv *priv; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + parent_np = of_get_parent(pdev->dev.of_node); + priv->regmap = syscon_node_to_regmap(parent_np); + of_node_put(parent_np); + if (IS_ERR(priv->regmap)) + return PTR_ERR(priv->regmap); + + priv->rcdev.owner = THIS_MODULE; + priv->rcdev.ops = &berlin_reset_ops; + priv->rcdev.of_node = pdev->dev.of_node; + priv->rcdev.of_reset_n_cells = 2; + priv->rcdev.of_xlate = berlin_reset_xlate; + + return reset_controller_register(&priv->rcdev); +} + +static const struct of_device_id berlin_reset_dt_match[] = { + { .compatible = "marvell,berlin2-reset" }, + { }, +}; +MODULE_DEVICE_TABLE(of, berlin_reset_dt_match); + +static struct platform_driver berlin_reset_driver = { + .probe = berlin2_reset_probe, + .driver = { + .name = "berlin2-reset", + .of_match_table = berlin_reset_dt_match, + }, +}; +module_platform_driver(berlin_reset_driver); + +MODULE_AUTHOR("Antoine Tenart "); +MODULE_AUTHOR("Sebastian Hesselbarth "); +MODULE_DESCRIPTION("Synaptics Berlin reset controller"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1