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-socfpga.c | 120 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 drivers/reset/reset-socfpga.c (limited to 'drivers/reset/reset-socfpga.c') diff --git a/drivers/reset/reset-socfpga.c b/drivers/reset/reset-socfpga.c new file mode 100644 index 000000000..da208270b --- /dev/null +++ b/drivers/reset/reset-socfpga.c @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018, Intel Corporation + * Copied from reset-sunxi.c + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define SOCFPGA_NR_BANKS 8 + +static int a10_reset_init(struct device_node *np) +{ + struct reset_simple_data *data; + struct resource res; + resource_size_t size; + int ret; + u32 reg_offset = 0x10; + + data = kzalloc_obj(*data); + if (!data) + return -ENOMEM; + + ret = of_address_to_resource(np, 0, &res); + if (ret) + goto err_alloc; + + size = resource_size(&res); + if (!request_mem_region(res.start, size, np->name)) { + ret = -EBUSY; + goto err_alloc; + } + + data->membase = ioremap(res.start, size); + if (!data->membase) { + ret = -ENOMEM; + goto release_region; + } + + if (of_property_read_u32(np, "altr,modrst-offset", ®_offset)) + pr_warn("missing altr,modrst-offset property, assuming 0x10\n"); + data->membase += reg_offset; + + spin_lock_init(&data->lock); + + data->rcdev.owner = THIS_MODULE; + data->rcdev.nr_resets = SOCFPGA_NR_BANKS * 32; + data->rcdev.ops = &reset_simple_ops; + data->rcdev.of_node = np; + data->status_active_low = true; + + ret = reset_controller_register(&data->rcdev); + if (ret) + pr_err("unable to register device\n"); + + return ret; + +release_region: + release_mem_region(res.start, size); + +err_alloc: + kfree(data); + return ret; +}; + +/* + * These are the reset controller we need to initialize early on in + * our system, before we can even think of using a regular device + * driver for it. + * The controllers that we can register through the regular device + * model are handled by the simple reset driver directly. + */ +static const struct of_device_id socfpga_early_reset_dt_ids[] __initconst = { + { .compatible = "altr,rst-mgr", }, + { /* sentinel */ }, +}; + +void __init socfpga_reset_init(void) +{ + struct device_node *np; + + for_each_matching_node(np, socfpga_early_reset_dt_ids) + a10_reset_init(np); +} + +/* + * The early driver is problematic, because it doesn't register + * itself as a driver. This causes certain device links to prevent + * consumer devices from probing. The hacky solution is to register + * an empty driver, whose only job is to attach itself to the reset + * manager and call probe. + */ +static const struct of_device_id socfpga_reset_dt_ids[] = { + { .compatible = "altr,rst-mgr", }, + { /* sentinel */ }, +}; + +static int reset_simple_probe(struct platform_device *pdev) +{ + return 0; +} + +static struct platform_driver reset_socfpga_driver = { + .probe = reset_simple_probe, + .driver = { + .name = "socfpga-reset", + .of_match_table = socfpga_reset_dt_ids, + }, +}; +builtin_platform_driver(reset_socfpga_driver); -- cgit v1.3.1