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, 287 insertions, 0 deletions

diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c
new file mode 100644
index 000000000..e7366fcb7
--- /dev/null
+++ b/drivers/acpi/acpi_apd.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD ACPI support for ACPI2platform device.
+ *
+ * Copyright (c) 2014,2015 AMD Corporation.
+ * Authors: Ken Xue <Ken.Xue@amd.com>
+ *	Wu, Jeff <Jeff.Wu@amd.com>
+ */
+
+#include <linux/acpi.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/platform_data/clk-fch.h>
+#include <linux/platform_device.h>
+#include <linux/units.h>
+
+#include "internal.h"
+
+struct apd_private_data;
+
+/**
+ * struct apd_device_desc - a descriptor for apd device
+ * @fixed_clk_rate: fixed rate input clock source for acpi device;
+ *			0 means no fixed rate input clock source
+ * @properties: build-in properties of the device such as UART
+ * @setup: a hook routine to set device resource during create platform device
+ *
+ * Device description defined as acpi_device_id.driver_data
+ */
+struct apd_device_desc {
+	unsigned int fixed_clk_rate;
+	struct property_entry *properties;
+	int (*setup)(struct apd_private_data *pdata);
+};
+
+struct apd_private_data {
+	struct clk *clk;
+	struct acpi_device *adev;
+	const struct apd_device_desc *dev_desc;
+};
+
+#if defined(CONFIG_X86_AMD_PLATFORM_DEVICE) || defined(CONFIG_ARM64)
+#define APD_ADDR(desc)	((unsigned long)&desc)
+
+static int acpi_apd_setup(struct apd_private_data *pdata)
+{
+	const struct apd_device_desc *dev_desc = pdata->dev_desc;
+	struct clk *clk;
+
+	if (dev_desc->fixed_clk_rate) {
+		clk = clk_register_fixed_rate(&pdata->adev->dev,
+					dev_name(&pdata->adev->dev),
+					NULL, 0, dev_desc->fixed_clk_rate);
+		clk_register_clkdev(clk, NULL, dev_name(&pdata->adev->dev));
+		pdata->clk = clk;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_X86_AMD_PLATFORM_DEVICE
+
+static int fch_misc_setup(struct apd_private_data *pdata)
+{
+	struct acpi_device *adev = pdata->adev;
+	const union acpi_object *obj;
+	struct platform_device *clkdev;
+	struct fch_clk_data *clk_data;
+	struct resource_entry *rentry;
+	struct list_head resource_list;
+	int ret;
+
+	clk_data = devm_kzalloc(&adev->dev, sizeof(*clk_data), GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_memory_resources(adev, &resource_list);
+	if (ret < 0)
+		return -ENOENT;
+
+	if (!acpi_dev_get_property(adev, "clk-name", ACPI_TYPE_STRING, &obj)) {
+		clk_data->name = devm_kzalloc(&adev->dev, obj->string.length,
+					      GFP_KERNEL);
+		if (!clk_data->name)
+			return -ENOMEM;
+
+		strscpy(clk_data->name, obj->string.pointer, obj->string.length);
+	} else {
+		/* Set default name to mclk if entry missing in firmware */
+		clk_data->name = "mclk";
+	}
+
+	list_for_each_entry(rentry, &resource_list, node) {
+		clk_data->base = devm_ioremap(&adev->dev, rentry->res->start,
+					      resource_size(rentry->res));
+		break;
+	}
+	if (!clk_data->base)
+		return -ENOMEM;
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	clkdev = platform_device_register_data(&adev->dev, "clk-fch",
+					       PLATFORM_DEVID_NONE, clk_data,
+					       sizeof(*clk_data));
+	return PTR_ERR_OR_ZERO(clkdev);
+}
+
+static const struct apd_device_desc cz_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 133 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc wt_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 150 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc wt_i3c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 125 * HZ_PER_MHZ,
+};
+
+static 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 apd_device_desc cz_uart_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 48 * HZ_PER_MHZ,
+	.properties = uart_properties,
+};
+
+static const struct apd_device_desc fch_misc_desc = {
+	.setup = fch_misc_setup,
+};
+#endif /* CONFIG_X86_AMD_PLATFORM_DEVICE */
+
+#ifdef CONFIG_ARM64
+static const struct apd_device_desc xgene_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 100 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc vulcan_spi_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 133 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hip07_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 200 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hip08_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 250 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hip08_lite_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 125 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc thunderx2_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 125 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc nxp_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 350 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hip08_spi_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 250 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc leca_spi_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 400 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc leca_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 250 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hjmc_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 200 * HZ_PER_MHZ,
+};
+
+#endif /* CONFIG_ARM64 */
+
+#endif
+
+/*
+ * Create platform device during acpi scan attach handle.
+ * Return value > 0 on success of creating device.
+ */
+static int acpi_apd_create_device(struct acpi_device *adev,
+				   const struct acpi_device_id *id)
+{
+	const struct apd_device_desc *dev_desc = (void *)id->driver_data;
+	struct apd_private_data *pdata;
+	struct platform_device *pdev;
+	int ret;
+
+	if (!dev_desc) {
+		pdev = acpi_create_platform_device(adev, NULL);
+		return IS_ERR_OR_NULL(pdev) ? PTR_ERR(pdev) : 1;
+	}
+
+	pdata = kzalloc_obj(*pdata);
+	if (!pdata)
+		return -ENOMEM;
+
+	pdata->adev = adev;
+	pdata->dev_desc = dev_desc;
+
+	if (dev_desc->setup) {
+		ret = dev_desc->setup(pdata);
+		if (ret)
+			goto err_out;
+	}
+
+	adev->driver_data = pdata;
+	pdev = acpi_create_platform_device(adev, dev_desc->properties);
+	if (!IS_ERR_OR_NULL(pdev))
+		return 1;
+
+	ret = PTR_ERR(pdev);
+	adev->driver_data = NULL;
+
+ err_out:
+	kfree(pdata);
+	return ret;
+}
+
+static const struct acpi_device_id acpi_apd_device_ids[] = {
+	/* Generic apd devices */
+#ifdef CONFIG_X86_AMD_PLATFORM_DEVICE
+	{ "AMD0010", APD_ADDR(cz_i2c_desc) },
+	{ "AMD0020", APD_ADDR(cz_uart_desc) },
+	{ "AMD0030", },
+	{ "AMD0040", APD_ADDR(fch_misc_desc)},
+	{ "AMDI0010", APD_ADDR(wt_i2c_desc) },
+	{ "AMDI0015", APD_ADDR(wt_i3c_desc) },
+	{ "AMDI0019", APD_ADDR(wt_i2c_desc) },
+	{ "AMDI0020", APD_ADDR(cz_uart_desc) },
+	{ "AMDI0022", APD_ADDR(cz_uart_desc) },
+	{ "HYGO0010", APD_ADDR(wt_i2c_desc) },
+#endif
+#ifdef CONFIG_ARM64
+	{ "APMC0D0F", APD_ADDR(xgene_i2c_desc) },
+	{ "BRCM900D", APD_ADDR(vulcan_spi_desc) },
+	{ "CAV900D",  APD_ADDR(vulcan_spi_desc) },
+	{ "CAV9007",  APD_ADDR(thunderx2_i2c_desc) },
+	{ "HISI02A1", APD_ADDR(hip07_i2c_desc) },
+	{ "HISI02A2", APD_ADDR(hip08_i2c_desc) },
+	{ "HISI02A3", APD_ADDR(hip08_lite_i2c_desc) },
+	{ "HISI0173", APD_ADDR(hip08_spi_desc) },
+	{ "HJMC3001", APD_ADDR(hjmc_i2c_desc) },
+	{ "LECA0002", APD_ADDR(leca_spi_desc) },
+	{ "LECA0003", APD_ADDR(leca_i2c_desc) },
+	{ "NXP0001", APD_ADDR(nxp_i2c_desc) },
+#endif
+	{ }
+};
+
+static struct acpi_scan_handler apd_handler = {
+	.ids = acpi_apd_device_ids,
+	.attach = acpi_apd_create_device,
+};
+
+void __init acpi_apd_init(void)
+{
+	acpi_scan_add_handler(&apd_handler);
+}