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/soc/nuvoton/Kconfig | 11 ++++ drivers/soc/nuvoton/Makefile | 2 + drivers/soc/nuvoton/wpcm450-soc.c | 109 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 122 insertions(+) create mode 100644 drivers/soc/nuvoton/Kconfig create mode 100644 drivers/soc/nuvoton/Makefile create mode 100644 drivers/soc/nuvoton/wpcm450-soc.c (limited to 'drivers/soc/nuvoton') diff --git a/drivers/soc/nuvoton/Kconfig b/drivers/soc/nuvoton/Kconfig new file mode 100644 index 000000000..df4618208 --- /dev/null +++ b/drivers/soc/nuvoton/Kconfig @@ -0,0 +1,11 @@ +# SPDX-License-Identifier: GPL-2.0 +menuconfig WPCM450_SOC + tristate "Nuvoton WPCM450 SoC driver" + default y if ARCH_WPCM450 + select SOC_BUS + help + Say Y here to compile the SoC information driver for Nuvoton + WPCM450 SoCs. + + This driver provides information such as the SoC model and + revision. diff --git a/drivers/soc/nuvoton/Makefile b/drivers/soc/nuvoton/Makefile new file mode 100644 index 000000000..e30317b4e --- /dev/null +++ b/drivers/soc/nuvoton/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_WPCM450_SOC) += wpcm450-soc.o diff --git a/drivers/soc/nuvoton/wpcm450-soc.c b/drivers/soc/nuvoton/wpcm450-soc.c new file mode 100644 index 000000000..5511bd284 --- /dev/null +++ b/drivers/soc/nuvoton/wpcm450-soc.c @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Nuvoton WPCM450 SoC Identification + * + * Copyright (C) 2022 Jonathan Neuschäfer + */ + +#include +#include +#include +#include +#include + +#define GCR_PDID 0 +#define PDID_CHIP(x) ((x) & 0x00ffffff) +#define CHIP_WPCM450 0x926450 +#define PDID_REV(x) ((x) >> 24) + +struct revision { + u8 number; + const char *name; +}; + +static const struct revision revisions[] __initconst = { + { 0x00, "Z1" }, + { 0x03, "Z2" }, + { 0x04, "Z21" }, + { 0x08, "A1" }, + { 0x09, "A2" }, + { 0x0a, "A3" }, + {} +}; + +static const char * __init get_revision(unsigned int rev) +{ + int i; + + for (i = 0; revisions[i].name; i++) + if (revisions[i].number == rev) + return revisions[i].name; + return NULL; +} + +static struct soc_device_attribute *wpcm450_attr; +static struct soc_device *wpcm450_soc; + +static int __init wpcm450_soc_init(void) +{ + struct soc_device_attribute *attr; + struct soc_device *soc; + const char *revision; + struct regmap *gcr; + u32 pdid; + int ret; + + if (!of_machine_is_compatible("nuvoton,wpcm450")) + return 0; + + gcr = syscon_regmap_lookup_by_compatible("nuvoton,wpcm450-gcr"); + if (IS_ERR(gcr)) + return PTR_ERR(gcr); + ret = regmap_read(gcr, GCR_PDID, &pdid); + if (ret) + return ret; + + if (PDID_CHIP(pdid) != CHIP_WPCM450) { + pr_warn("Unknown chip ID in GCR.PDID: 0x%06x\n", PDID_CHIP(pdid)); + return -ENODEV; + } + + revision = get_revision(PDID_REV(pdid)); + if (!revision) { + pr_warn("Unknown chip revision in GCR.PDID: 0x%02x\n", PDID_REV(pdid)); + return -ENODEV; + } + + attr = kzalloc_obj(*attr); + if (!attr) + return -ENOMEM; + + attr->family = "Nuvoton NPCM"; + attr->soc_id = "WPCM450"; + attr->revision = revision; + soc = soc_device_register(attr); + if (IS_ERR(soc)) { + kfree(attr); + pr_warn("Could not register SoC device\n"); + return PTR_ERR(soc); + } + + wpcm450_soc = soc; + wpcm450_attr = attr; + return 0; +} +module_init(wpcm450_soc_init); + +static void __exit wpcm450_soc_exit(void) +{ + if (wpcm450_soc) { + soc_device_unregister(wpcm450_soc); + wpcm450_soc = NULL; + kfree(wpcm450_attr); + } +} +module_exit(wpcm450_soc_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jonathan Neuschäfer"); +MODULE_DESCRIPTION("Nuvoton WPCM450 SoC Identification driver"); -- cgit v1.3.1