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/vt8500/Kconfig | 19 ++++++ drivers/soc/vt8500/Makefile | 2 + drivers/soc/vt8500/wmt-socinfo.c | 125 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 146 insertions(+) create mode 100644 drivers/soc/vt8500/Kconfig create mode 100644 drivers/soc/vt8500/Makefile create mode 100644 drivers/soc/vt8500/wmt-socinfo.c (limited to 'drivers/soc/vt8500') diff --git a/drivers/soc/vt8500/Kconfig b/drivers/soc/vt8500/Kconfig new file mode 100644 index 000000000..b4cc0ba11 --- /dev/null +++ b/drivers/soc/vt8500/Kconfig @@ -0,0 +1,19 @@ +# SPDX-License-Identifier: GPL-2.0-only + +if ARCH_VT8500 || COMPILE_TEST + +menu "VIA/WonderMedia SoC drivers" + +config WMT_SOCINFO + bool "VIA/WonderMedia SoC Information driver" + default ARCH_VT8500 + select SOC_BUS + help + Say yes to support decoding of VIA/WonderMedia system configuration + register information. This currently includes just the chip ID register + which helps identify the exact hardware revision of the SoC the kernel + is running on (to know if any revision-specific quirks are required) + +endmenu + +endif diff --git a/drivers/soc/vt8500/Makefile b/drivers/soc/vt8500/Makefile new file mode 100644 index 000000000..05964c5f2 --- /dev/null +++ b/drivers/soc/vt8500/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_WMT_SOCINFO) += wmt-socinfo.o diff --git a/drivers/soc/vt8500/wmt-socinfo.c b/drivers/soc/vt8500/wmt-socinfo.c new file mode 100644 index 000000000..461f8c1ae --- /dev/null +++ b/drivers/soc/vt8500/wmt-socinfo.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2025 Alexey Charkov + * Based on aspeed-socinfo.c + */ + +#include +#include +#include +#include +#include +#include + +static const struct { + const char *name; + const u32 id; +} chip_id_table[] = { + /* VIA */ + { "VT8420", 0x3300 }, + { "VT8430", 0x3357 }, + { "VT8500", 0x3400 }, + + /* WonderMedia */ + { "WM8425", 0x3429 }, + { "WM8435", 0x3437 }, + { "WM8440", 0x3451 }, + { "WM8505", 0x3426 }, + { "WM8650", 0x3465 }, + { "WM8750", 0x3445 }, + { "WM8850", 0x3481 }, + { "WM8880", 0x3498 }, +}; + +static const char *sccid_to_name(u32 sccid) +{ + u32 id = sccid >> 16; + unsigned int i; + + for (i = 0 ; i < ARRAY_SIZE(chip_id_table) ; ++i) { + if (chip_id_table[i].id == id) + return chip_id_table[i].name; + } + + return "Unknown"; +} + +static int wmt_socinfo_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct soc_device_attribute *attrs; + struct soc_device *soc_dev; + char letter, digit; + void __iomem *reg; + u32 sccid; + + reg = devm_of_iomap(&pdev->dev, np, 0, NULL); + if (IS_ERR(reg)) + return PTR_ERR(reg); + + sccid = readl(reg); + + attrs = devm_kzalloc(&pdev->dev, sizeof(*attrs), GFP_KERNEL); + if (!attrs) + return -ENOMEM; + + /* + * Machine: VIA APC Rock + * Family: WM8850 + * Revision: A2 + * SoC ID: raw silicon revision id (34810103 in hexadecimal) + */ + + attrs->family = sccid_to_name(sccid); + + letter = (sccid >> 8) & 0xf; + letter = (letter - 1) + 'A'; + digit = sccid & 0xff; + digit = (digit - 1) + '0'; + attrs->revision = devm_kasprintf(&pdev->dev, GFP_KERNEL, + "%c%c", letter, digit); + + attrs->soc_id = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%08x", sccid); + + if (!attrs->revision || !attrs->soc_id) + return -ENOMEM; + + soc_dev = soc_device_register(attrs); + if (IS_ERR(soc_dev)) + return PTR_ERR(soc_dev); + + dev_info(&pdev->dev, + "VIA/WonderMedia %s rev %s (%s)\n", + attrs->family, + attrs->revision, + attrs->soc_id); + + platform_set_drvdata(pdev, soc_dev); + return 0; +} + +static void wmt_socinfo_remove(struct platform_device *pdev) +{ + struct soc_device *soc_dev = platform_get_drvdata(pdev); + + soc_device_unregister(soc_dev); +} + +static const struct of_device_id wmt_socinfo_ids[] = { + { .compatible = "via,vt8500-scc-id" }, + { /* Sentinel */ }, +}; + +static struct platform_driver wmt_socinfo = { + .probe = wmt_socinfo_probe, + .remove = wmt_socinfo_remove, + .driver = { + .name = "wmt-socinfo", + .of_match_table = wmt_socinfo_ids, + }, +}; +module_platform_driver(wmt_socinfo); + +MODULE_AUTHOR("Alexey Charkov "); +MODULE_DESCRIPTION("VIA/WonderMedia socinfo driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1