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/firmware/imx/sm-cpu.c | 85 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 drivers/firmware/imx/sm-cpu.c (limited to 'drivers/firmware/imx/sm-cpu.c') diff --git a/drivers/firmware/imx/sm-cpu.c b/drivers/firmware/imx/sm-cpu.c new file mode 100644 index 000000000..091b014f7 --- /dev/null +++ b/drivers/firmware/imx/sm-cpu.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2025 NXP + */ + +#include +#include +#include +#include +#include +#include + +static const struct scmi_imx_cpu_proto_ops *imx_cpu_ops; +static struct scmi_protocol_handle *ph; + +int scmi_imx_cpu_reset_vector_set(u32 cpuid, u64 vector, bool start, bool boot, + bool resume) +{ + if (!ph) + return -EPROBE_DEFER; + + return imx_cpu_ops->cpu_reset_vector_set(ph, cpuid, vector, start, + boot, resume); +} +EXPORT_SYMBOL(scmi_imx_cpu_reset_vector_set); + +int scmi_imx_cpu_start(u32 cpuid, bool start) +{ + if (!ph) + return -EPROBE_DEFER; + + if (start) + return imx_cpu_ops->cpu_start(ph, cpuid, true); + + return imx_cpu_ops->cpu_start(ph, cpuid, false); +}; +EXPORT_SYMBOL(scmi_imx_cpu_start); + +int scmi_imx_cpu_started(u32 cpuid, bool *started) +{ + if (!ph) + return -EPROBE_DEFER; + + if (!started) + return -EINVAL; + + return imx_cpu_ops->cpu_started(ph, cpuid, started); +}; +EXPORT_SYMBOL(scmi_imx_cpu_started); + +static int scmi_imx_cpu_probe(struct scmi_device *sdev) +{ + const struct scmi_handle *handle = sdev->handle; + + if (!handle) + return -ENODEV; + + if (imx_cpu_ops) { + dev_err(&sdev->dev, "sm cpu already initialized\n"); + return -EEXIST; + } + + imx_cpu_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_IMX_CPU, &ph); + if (IS_ERR(imx_cpu_ops)) + return PTR_ERR(imx_cpu_ops); + + return 0; +} + +static const struct scmi_device_id scmi_id_table[] = { + { SCMI_PROTOCOL_IMX_CPU, "imx-cpu" }, + { }, +}; +MODULE_DEVICE_TABLE(scmi, scmi_id_table); + +static struct scmi_driver scmi_imx_cpu_driver = { + .name = "scmi-imx-cpu", + .probe = scmi_imx_cpu_probe, + .id_table = scmi_id_table, +}; +module_scmi_driver(scmi_imx_cpu_driver); + +MODULE_AUTHOR("Peng Fan "); +MODULE_DESCRIPTION("IMX SM CPU driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1