ftrace: Synchronize the initialization of ftrace_opsgrafted

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 <rostedt@goodmis.org>

1 files changed, 224 insertions, 0 deletions

diff --git a/drivers/mfd/intel-lpss-acpi.c b/drivers/mfd/intel-lpss-acpi.c
new file mode 100644
index 000000000..d4b24a717
--- /dev/null
+++ b/drivers/mfd/intel-lpss-acpi.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel LPSS ACPI support.
+ *
+ * Copyright (C) 2015, Intel Corporation
+ *
+ * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *          Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/device.h>
+#include <linux/gfp_types.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#include <linux/pxa2xx_ssp.h>
+
+#include <asm/errno.h>
+
+#include "intel-lpss.h"
+
+static const struct property_entry spt_spi_properties[] = {
+	PROPERTY_ENTRY_U32("intel,spi-pxa2xx-type", LPSS_SPT_SSP),
+	{ }
+};
+
+static const struct software_node spt_spi_node = {
+	.properties = spt_spi_properties,
+};
+
+static const struct intel_lpss_platform_info spt_info = {
+	.clk_rate = 120000000,
+	.swnode = &spt_spi_node,
+};
+
+static const struct property_entry spt_i2c_properties[] = {
+	PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 230),
+	{ },
+};
+
+static const struct software_node spt_i2c_node = {
+	.properties = spt_i2c_properties,
+};
+
+static const struct intel_lpss_platform_info spt_i2c_info = {
+	.clk_rate = 120000000,
+	.swnode = &spt_i2c_node,
+};
+
+static const struct property_entry uart_properties[] = {
+	PROPERTY_ENTRY_U32("reg-io-width", 4),
+	PROPERTY_ENTRY_U32("reg-shift", 2),
+	PROPERTY_ENTRY_BOOL("snps,uart-16550-compatible"),
+	{ },
+};
+
+static const struct software_node uart_node = {
+	.properties = uart_properties,
+};
+
+static const struct intel_lpss_platform_info spt_uart_info = {
+	.clk_rate = 120000000,
+	.clk_con_id = "baudclk",
+	.swnode = &uart_node,
+};
+
+static const struct property_entry bxt_spi_properties[] = {
+	PROPERTY_ENTRY_U32("intel,spi-pxa2xx-type", LPSS_BXT_SSP),
+	{ }
+};
+
+static const struct software_node bxt_spi_node = {
+	.properties = bxt_spi_properties,
+};
+
+static const struct intel_lpss_platform_info bxt_info = {
+	.clk_rate = 100000000,
+	.swnode = &bxt_spi_node,
+};
+
+static const struct property_entry bxt_i2c_properties[] = {
+	PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 42),
+	PROPERTY_ENTRY_U32("i2c-sda-falling-time-ns", 171),
+	PROPERTY_ENTRY_U32("i2c-scl-falling-time-ns", 208),
+	{ },
+};
+
+static const struct software_node bxt_i2c_node = {
+	.properties = bxt_i2c_properties,
+};
+
+static const struct intel_lpss_platform_info bxt_i2c_info = {
+	.clk_rate = 133000000,
+	.swnode = &bxt_i2c_node,
+};
+
+static const struct property_entry apl_i2c_properties[] = {
+	PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 207),
+	PROPERTY_ENTRY_U32("i2c-sda-falling-time-ns", 171),
+	PROPERTY_ENTRY_U32("i2c-scl-falling-time-ns", 208),
+	{ },
+};
+
+static const struct software_node apl_i2c_node = {
+	.properties = apl_i2c_properties,
+};
+
+static const struct intel_lpss_platform_info apl_i2c_info = {
+	.clk_rate = 133000000,
+	.swnode = &apl_i2c_node,
+};
+
+static const struct property_entry cnl_spi_properties[] = {
+	PROPERTY_ENTRY_U32("intel,spi-pxa2xx-type", LPSS_CNL_SSP),
+	{ }
+};
+
+static const struct software_node cnl_spi_node = {
+	.properties = cnl_spi_properties,
+};
+
+static const struct intel_lpss_platform_info cnl_info = {
+	.clk_rate = 120000000,
+	.swnode = &cnl_spi_node,
+};
+
+static const struct intel_lpss_platform_info cnl_i2c_info = {
+	.clk_rate = 216000000,
+	.swnode = &spt_i2c_node,
+};
+
+static const struct acpi_device_id intel_lpss_acpi_ids[] = {
+	/* SPT */
+	{ "INT3440", (kernel_ulong_t)&spt_info },
+	{ "INT3441", (kernel_ulong_t)&spt_info },
+	{ "INT3442", (kernel_ulong_t)&spt_i2c_info },
+	{ "INT3443", (kernel_ulong_t)&spt_i2c_info },
+	{ "INT3444", (kernel_ulong_t)&spt_i2c_info },
+	{ "INT3445", (kernel_ulong_t)&spt_i2c_info },
+	{ "INT3446", (kernel_ulong_t)&spt_i2c_info },
+	{ "INT3447", (kernel_ulong_t)&spt_i2c_info },
+	{ "INT3448", (kernel_ulong_t)&spt_uart_info },
+	{ "INT3449", (kernel_ulong_t)&spt_uart_info },
+	{ "INT344A", (kernel_ulong_t)&spt_uart_info },
+	/* CNL */
+	{ "INT34B0", (kernel_ulong_t)&cnl_info },
+	{ "INT34B1", (kernel_ulong_t)&cnl_info },
+	{ "INT34B2", (kernel_ulong_t)&cnl_i2c_info },
+	{ "INT34B3", (kernel_ulong_t)&cnl_i2c_info },
+	{ "INT34B4", (kernel_ulong_t)&cnl_i2c_info },
+	{ "INT34B5", (kernel_ulong_t)&cnl_i2c_info },
+	{ "INT34B6", (kernel_ulong_t)&cnl_i2c_info },
+	{ "INT34B7", (kernel_ulong_t)&cnl_i2c_info },
+	{ "INT34B8", (kernel_ulong_t)&spt_uart_info },
+	{ "INT34B9", (kernel_ulong_t)&spt_uart_info },
+	{ "INT34BA", (kernel_ulong_t)&spt_uart_info },
+	{ "INT34BC", (kernel_ulong_t)&cnl_info },
+	/* BXT */
+	{ "80860AAC", (kernel_ulong_t)&bxt_i2c_info },
+	{ "80860ABC", (kernel_ulong_t)&bxt_info },
+	{ "80860AC2", (kernel_ulong_t)&bxt_info },
+	/* APL */
+	{ "80865AAC", (kernel_ulong_t)&apl_i2c_info },
+	{ "80865ABC", (kernel_ulong_t)&bxt_info },
+	{ "80865AC2", (kernel_ulong_t)&bxt_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, intel_lpss_acpi_ids);
+
+static int intel_lpss_acpi_probe(struct platform_device *pdev)
+{
+	const struct intel_lpss_platform_info *data;
+	struct intel_lpss_platform_info *info;
+	int ret;
+
+	data = device_get_match_data(&pdev->dev);
+	if (!data)
+		return -ENODEV;
+
+	info = devm_kmemdup(&pdev->dev, data, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	/* No need to check mem and irq here as intel_lpss_probe() does it for us */
+	info->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	info->irq = platform_get_irq(pdev, 0);
+
+	ret = intel_lpss_probe(&pdev->dev, info);
+	if (ret)
+		return ret;
+
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	return 0;
+}
+
+static void intel_lpss_acpi_remove(struct platform_device *pdev)
+{
+	intel_lpss_remove(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+}
+
+static struct platform_driver intel_lpss_acpi_driver = {
+	.probe = intel_lpss_acpi_probe,
+	.remove = intel_lpss_acpi_remove,
+	.driver = {
+		.name = "intel-lpss",
+		.acpi_match_table = intel_lpss_acpi_ids,
+		.pm = pm_ptr(&intel_lpss_pm_ops),
+	},
+};
+
+module_platform_driver(intel_lpss_acpi_driver);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_DESCRIPTION("Intel LPSS ACPI driver");
+MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS("INTEL_LPSS");