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, 344 insertions, 0 deletions

diff --git a/drivers/peci/cpu.c b/drivers/peci/cpu.c
new file mode 100644
index 000000000..c9fc06c9f
--- /dev/null
+++ b/drivers/peci/cpu.c
@@ -0,0 +1,344 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2021 Intel Corporation
+
+#include <linux/auxiliary_bus.h>
+#include <linux/module.h>
+#include <linux/peci.h>
+#include <linux/peci-cpu.h>
+#include <linux/slab.h>
+
+#include "internal.h"
+
+/**
+ * peci_temp_read() - read the maximum die temperature from PECI target device
+ * @device: PECI device to which request is going to be sent
+ * @temp_raw: where to store the read temperature
+ *
+ * It uses GetTemp PECI command.
+ *
+ * Return: 0 if succeeded, other values in case errors.
+ */
+int peci_temp_read(struct peci_device *device, s16 *temp_raw)
+{
+	struct peci_request *req;
+
+	req = peci_xfer_get_temp(device);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	*temp_raw = peci_request_temp_read(req);
+
+	peci_request_free(req);
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(peci_temp_read, "PECI_CPU");
+
+/**
+ * peci_pcs_read() - read PCS register
+ * @device: PECI device to which request is going to be sent
+ * @index: PCS index
+ * @param: PCS parameter
+ * @data: where to store the read data
+ *
+ * It uses RdPkgConfig PECI command.
+ *
+ * Return: 0 if succeeded, other values in case errors.
+ */
+int peci_pcs_read(struct peci_device *device, u8 index, u16 param, u32 *data)
+{
+	struct peci_request *req;
+	int ret;
+
+	req = peci_xfer_pkg_cfg_readl(device, index, param);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	ret = peci_request_status(req);
+	if (ret)
+		goto out_req_free;
+
+	*data = peci_request_data_readl(req);
+out_req_free:
+	peci_request_free(req);
+
+	return ret;
+}
+EXPORT_SYMBOL_NS_GPL(peci_pcs_read, "PECI_CPU");
+
+/**
+ * peci_pci_local_read() - read 32-bit memory location using raw address
+ * @device: PECI device to which request is going to be sent
+ * @bus: bus
+ * @dev: device
+ * @func: function
+ * @reg: register
+ * @data: where to store the read data
+ *
+ * It uses RdPCIConfigLocal PECI command.
+ *
+ * Return: 0 if succeeded, other values in case errors.
+ */
+int peci_pci_local_read(struct peci_device *device, u8 bus, u8 dev, u8 func,
+			u16 reg, u32 *data)
+{
+	struct peci_request *req;
+	int ret;
+
+	req = peci_xfer_pci_cfg_local_readl(device, bus, dev, func, reg);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	ret = peci_request_status(req);
+	if (ret)
+		goto out_req_free;
+
+	*data = peci_request_data_readl(req);
+out_req_free:
+	peci_request_free(req);
+
+	return ret;
+}
+EXPORT_SYMBOL_NS_GPL(peci_pci_local_read, "PECI_CPU");
+
+/**
+ * peci_ep_pci_local_read() - read 32-bit memory location using raw address
+ * @device: PECI device to which request is going to be sent
+ * @seg: PCI segment
+ * @bus: bus
+ * @dev: device
+ * @func: function
+ * @reg: register
+ * @data: where to store the read data
+ *
+ * Like &peci_pci_local_read, but it uses RdEndpointConfig PECI command.
+ *
+ * Return: 0 if succeeded, other values in case errors.
+ */
+int peci_ep_pci_local_read(struct peci_device *device, u8 seg,
+			   u8 bus, u8 dev, u8 func, u16 reg, u32 *data)
+{
+	struct peci_request *req;
+	int ret;
+
+	req = peci_xfer_ep_pci_cfg_local_readl(device, seg, bus, dev, func, reg);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	ret = peci_request_status(req);
+	if (ret)
+		goto out_req_free;
+
+	*data = peci_request_data_readl(req);
+out_req_free:
+	peci_request_free(req);
+
+	return ret;
+}
+EXPORT_SYMBOL_NS_GPL(peci_ep_pci_local_read, "PECI_CPU");
+
+/**
+ * peci_mmio_read() - read 32-bit memory location using 64-bit bar offset address
+ * @device: PECI device to which request is going to be sent
+ * @bar: PCI bar
+ * @seg: PCI segment
+ * @bus: bus
+ * @dev: device
+ * @func: function
+ * @address: 64-bit MMIO address
+ * @data: where to store the read data
+ *
+ * It uses RdEndpointConfig PECI command.
+ *
+ * Return: 0 if succeeded, other values in case errors.
+ */
+int peci_mmio_read(struct peci_device *device, u8 bar, u8 seg,
+		   u8 bus, u8 dev, u8 func, u64 address, u32 *data)
+{
+	struct peci_request *req;
+	int ret;
+
+	req = peci_xfer_ep_mmio64_readl(device, bar, seg, bus, dev, func, address);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	ret = peci_request_status(req);
+	if (ret)
+		goto out_req_free;
+
+	*data = peci_request_data_readl(req);
+out_req_free:
+	peci_request_free(req);
+
+	return ret;
+}
+EXPORT_SYMBOL_NS_GPL(peci_mmio_read, "PECI_CPU");
+
+static const char * const peci_adev_types[] = {
+	"cputemp",
+	"dimmtemp",
+};
+
+struct peci_cpu {
+	struct peci_device *device;
+	const struct peci_device_id *id;
+};
+
+static void adev_release(struct device *dev)
+{
+	struct auxiliary_device *adev = to_auxiliary_dev(dev);
+
+	kfree(adev->name);
+	kfree(adev);
+}
+
+static struct auxiliary_device *adev_alloc(struct peci_cpu *priv, int idx)
+{
+	struct peci_controller *controller = to_peci_controller(priv->device->dev.parent);
+	struct auxiliary_device *adev;
+	const char *name;
+	int ret;
+
+	adev = kzalloc_obj(*adev);
+	if (!adev)
+		return ERR_PTR(-ENOMEM);
+
+	name = kasprintf(GFP_KERNEL, "%s.%s", peci_adev_types[idx], (const char *)priv->id->data);
+	if (!name) {
+		ret = -ENOMEM;
+		goto free_adev;
+	}
+
+	adev->name = name;
+	adev->dev.parent = &priv->device->dev;
+	adev->dev.release = adev_release;
+	adev->id = (controller->id << 16) | (priv->device->addr);
+
+	ret = auxiliary_device_init(adev);
+	if (ret)
+		goto free_name;
+
+	return adev;
+
+free_name:
+	kfree(name);
+free_adev:
+	kfree(adev);
+	return ERR_PTR(ret);
+}
+
+static void unregister_adev(void *_adev)
+{
+	struct auxiliary_device *adev = _adev;
+
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
+
+static int devm_adev_add(struct device *dev, int idx)
+{
+	struct peci_cpu *priv = dev_get_drvdata(dev);
+	struct auxiliary_device *adev;
+	int ret;
+
+	adev = adev_alloc(priv, idx);
+	if (IS_ERR(adev))
+		return PTR_ERR(adev);
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(&priv->device->dev, unregister_adev, adev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void peci_cpu_add_adevices(struct peci_cpu *priv)
+{
+	struct device *dev = &priv->device->dev;
+	int ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(peci_adev_types); i++) {
+		ret = devm_adev_add(dev, i);
+		if (ret) {
+			dev_warn(dev, "Failed to register PECI auxiliary: %s, ret = %d\n",
+				 peci_adev_types[i], ret);
+			continue;
+		}
+	}
+}
+
+static int
+peci_cpu_probe(struct peci_device *device, const struct peci_device_id *id)
+{
+	struct device *dev = &device->dev;
+	struct peci_cpu *priv;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, priv);
+	priv->device = device;
+	priv->id = id;
+
+	peci_cpu_add_adevices(priv);
+
+	return 0;
+}
+
+static const struct peci_device_id peci_cpu_device_ids[] = {
+	{ /* Haswell Xeon */
+		.x86_vfm = INTEL_HASWELL_X,
+		.data	= "hsx",
+	},
+	{ /* Broadwell Xeon */
+		.x86_vfm = INTEL_BROADWELL_X,
+		.data	= "bdx",
+	},
+	{ /* Broadwell Xeon D */
+		.x86_vfm = INTEL_BROADWELL_D,
+		.data	= "bdxd",
+	},
+	{ /* Skylake Xeon */
+		.x86_vfm = INTEL_SKYLAKE_X,
+		.data	= "skx",
+	},
+	{ /* Icelake Xeon */
+		.x86_vfm = INTEL_ICELAKE_X,
+		.data	= "icx",
+	},
+	{ /* Icelake Xeon D */
+		.x86_vfm = INTEL_ICELAKE_D,
+		.data	= "icxd",
+	},
+	{ /* Sapphire Rapids Xeon */
+		.x86_vfm = INTEL_SAPPHIRERAPIDS_X,
+		.data	= "spr",
+	},
+	{ /* Emerald Rapids Xeon */
+		.x86_vfm  = INTEL_EMERALDRAPIDS_X,
+		.data  = "emr",
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(peci, peci_cpu_device_ids);
+
+static struct peci_driver peci_cpu_driver = {
+	.probe		= peci_cpu_probe,
+	.id_table	= peci_cpu_device_ids,
+	.driver		= {
+		.name		= "peci-cpu",
+	},
+};
+module_peci_driver(peci_cpu_driver);
+
+MODULE_AUTHOR("Iwona Winiarska <iwona.winiarska@intel.com>");
+MODULE_DESCRIPTION("PECI CPU driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PECI");