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, 601 insertions, 0 deletions

diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
new file mode 100644
index 000000000..0fd59c73f
--- /dev/null
+++ b/drivers/soc/ti/pruss.c
@@ -0,0 +1,601 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PRU-ICSS platform driver for various TI SoCs
+ *
+ * Copyright (C) 2014-2020 Texas Instruments Incorporated - http://www.ti.com/
+ * Author(s):
+ *	Suman Anna <s-anna@ti.com>
+ *	Andrew F. Davis <afd@ti.com>
+ *	Tero Kristo <t-kristo@ti.com>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pruss_driver.h>
+#include <linux/regmap.h>
+#include <linux/remoteproc.h>
+#include <linux/slab.h>
+#include "pruss.h"
+
+/**
+ * struct pruss_private_data - PRUSS driver private data
+ * @has_no_sharedram: flag to indicate the absence of PRUSS Shared Data RAM
+ * @has_core_mux_clock: flag to indicate the presence of PRUSS core clock
+ */
+struct pruss_private_data {
+	bool has_no_sharedram;
+	bool has_core_mux_clock;
+};
+
+/**
+ * pruss_get() - get the pruss for a given PRU remoteproc
+ * @rproc: remoteproc handle of a PRU instance
+ *
+ * Finds the parent pruss device for a PRU given the @rproc handle of the
+ * PRU remote processor. This function increments the pruss device's refcount,
+ * so always use pruss_put() to decrement it back once pruss isn't needed
+ * anymore.
+ *
+ * This API doesn't check if @rproc is valid or not. It is expected the caller
+ * will have done a pru_rproc_get() on @rproc, before calling this API to make
+ * sure that @rproc is valid.
+ *
+ * Return: pruss handle on success, and an ERR_PTR on failure using one
+ * of the following error values
+ *    -EINVAL if invalid parameter
+ *    -ENODEV if PRU device or PRUSS device is not found
+ */
+struct pruss *pruss_get(struct rproc *rproc)
+{
+	struct pruss *pruss;
+	struct device *dev;
+	struct platform_device *ppdev;
+
+	if (IS_ERR_OR_NULL(rproc))
+		return ERR_PTR(-EINVAL);
+
+	dev = &rproc->dev;
+
+	/* make sure it is PRU rproc */
+	if (!dev->parent || !is_pru_rproc(dev->parent))
+		return ERR_PTR(-ENODEV);
+
+	ppdev = to_platform_device(dev->parent->parent);
+	pruss = platform_get_drvdata(ppdev);
+	if (!pruss)
+		return ERR_PTR(-ENODEV);
+
+	get_device(pruss->dev);
+
+	return pruss;
+}
+EXPORT_SYMBOL_GPL(pruss_get);
+
+/**
+ * pruss_put() - decrement pruss device's usecount
+ * @pruss: pruss handle
+ *
+ * Complimentary function for pruss_get(). Needs to be called
+ * after the PRUSS is used, and only if the pruss_get() succeeds.
+ */
+void pruss_put(struct pruss *pruss)
+{
+	if (IS_ERR_OR_NULL(pruss))
+		return;
+
+	put_device(pruss->dev);
+}
+EXPORT_SYMBOL_GPL(pruss_put);
+
+/**
+ * pruss_request_mem_region() - request a memory resource
+ * @pruss: the pruss instance
+ * @mem_id: the memory resource id
+ * @region: pointer to memory region structure to be filled in
+ *
+ * This function allows a client driver to request a memory resource,
+ * and if successful, will let the client driver own the particular
+ * memory region until released using the pruss_release_mem_region()
+ * API.
+ *
+ * Return: 0 if requested memory region is available (in such case pointer to
+ * memory region is returned via @region), an error otherwise
+ */
+int pruss_request_mem_region(struct pruss *pruss, enum pruss_mem mem_id,
+			     struct pruss_mem_region *region)
+{
+	if (!pruss || !region || mem_id >= PRUSS_MEM_MAX)
+		return -EINVAL;
+
+	mutex_lock(&pruss->lock);
+
+	if (pruss->mem_in_use[mem_id]) {
+		mutex_unlock(&pruss->lock);
+		return -EBUSY;
+	}
+
+	*region = pruss->mem_regions[mem_id];
+	pruss->mem_in_use[mem_id] = region;
+
+	mutex_unlock(&pruss->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pruss_request_mem_region);
+
+/**
+ * pruss_release_mem_region() - release a memory resource
+ * @pruss: the pruss instance
+ * @region: the memory region to release
+ *
+ * This function is the complimentary function to
+ * pruss_request_mem_region(), and allows the client drivers to
+ * release back a memory resource.
+ *
+ * Return: 0 on success, an error code otherwise
+ */
+int pruss_release_mem_region(struct pruss *pruss,
+			     struct pruss_mem_region *region)
+{
+	int id;
+
+	if (!pruss || !region)
+		return -EINVAL;
+
+	mutex_lock(&pruss->lock);
+
+	/* find out the memory region being released */
+	for (id = 0; id < PRUSS_MEM_MAX; id++) {
+		if (pruss->mem_in_use[id] == region)
+			break;
+	}
+
+	if (id == PRUSS_MEM_MAX) {
+		mutex_unlock(&pruss->lock);
+		return -EINVAL;
+	}
+
+	pruss->mem_in_use[id] = NULL;
+
+	mutex_unlock(&pruss->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pruss_release_mem_region);
+
+/**
+ * pruss_cfg_get_gpmux() - get the current GPMUX value for a PRU device
+ * @pruss: pruss instance
+ * @pru_id: PRU identifier (0-1)
+ * @mux: pointer to store the current mux value into
+ *
+ * Return: 0 on success, or an error code otherwise
+ */
+int pruss_cfg_get_gpmux(struct pruss *pruss, enum pruss_pru_id pru_id, u8 *mux)
+{
+	int ret;
+	u32 val;
+
+	if (pru_id >= PRUSS_NUM_PRUS || !mux)
+		return -EINVAL;
+
+	ret = pruss_cfg_read(pruss, PRUSS_CFG_GPCFG(pru_id), &val);
+	if (!ret)
+		*mux = (u8)((val & PRUSS_GPCFG_PRU_MUX_SEL_MASK) >>
+			    PRUSS_GPCFG_PRU_MUX_SEL_SHIFT);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pruss_cfg_get_gpmux);
+
+/**
+ * pruss_cfg_set_gpmux() - set the GPMUX value for a PRU device
+ * @pruss: pruss instance
+ * @pru_id: PRU identifier (0-1)
+ * @mux: new mux value for PRU
+ *
+ * Return: 0 on success, or an error code otherwise
+ */
+int pruss_cfg_set_gpmux(struct pruss *pruss, enum pruss_pru_id pru_id, u8 mux)
+{
+	if (mux >= PRUSS_GP_MUX_SEL_MAX ||
+	    pru_id >= PRUSS_NUM_PRUS)
+		return -EINVAL;
+
+	return pruss_cfg_update(pruss, PRUSS_CFG_GPCFG(pru_id),
+				PRUSS_GPCFG_PRU_MUX_SEL_MASK,
+				(u32)mux << PRUSS_GPCFG_PRU_MUX_SEL_SHIFT);
+}
+EXPORT_SYMBOL_GPL(pruss_cfg_set_gpmux);
+
+/**
+ * pruss_cfg_gpimode() - set the GPI mode of the PRU
+ * @pruss: the pruss instance handle
+ * @pru_id: id of the PRU core within the PRUSS
+ * @mode: GPI mode to set
+ *
+ * Sets the GPI mode for a given PRU by programming the
+ * corresponding PRUSS_CFG_GPCFGx register
+ *
+ * Return: 0 on success, or an error code otherwise
+ */
+int pruss_cfg_gpimode(struct pruss *pruss, enum pruss_pru_id pru_id,
+		      enum pruss_gpi_mode mode)
+{
+	if (pru_id >= PRUSS_NUM_PRUS || mode >= PRUSS_GPI_MODE_MAX)
+		return -EINVAL;
+
+	return pruss_cfg_update(pruss, PRUSS_CFG_GPCFG(pru_id),
+				PRUSS_GPCFG_PRU_GPI_MODE_MASK,
+				mode << PRUSS_GPCFG_PRU_GPI_MODE_SHIFT);
+}
+EXPORT_SYMBOL_GPL(pruss_cfg_gpimode);
+
+/**
+ * pruss_cfg_miirt_enable() - Enable/disable MII RT Events
+ * @pruss: the pruss instance
+ * @enable: enable/disable
+ *
+ * Enable/disable the MII RT Events for the PRUSS.
+ *
+ * Return: 0 on success, or an error code otherwise
+ */
+int pruss_cfg_miirt_enable(struct pruss *pruss, bool enable)
+{
+	u32 set = enable ? PRUSS_MII_RT_EVENT_EN : 0;
+
+	return pruss_cfg_update(pruss, PRUSS_CFG_MII_RT,
+				PRUSS_MII_RT_EVENT_EN, set);
+}
+EXPORT_SYMBOL_GPL(pruss_cfg_miirt_enable);
+
+/**
+ * pruss_cfg_xfr_enable() - Enable/disable XIN XOUT shift functionality
+ * @pruss: the pruss instance
+ * @pru_type: PRU core type identifier
+ * @enable: enable/disable
+ *
+ * Return: 0 on success, or an error code otherwise
+ */
+int pruss_cfg_xfr_enable(struct pruss *pruss, enum pru_type pru_type,
+			 bool enable)
+{
+	u32 mask, set;
+
+	switch (pru_type) {
+	case PRU_TYPE_PRU:
+		mask = PRUSS_SPP_XFER_SHIFT_EN;
+		break;
+	case PRU_TYPE_RTU:
+		mask = PRUSS_SPP_RTU_XFR_SHIFT_EN;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	set = enable ? mask : 0;
+
+	return pruss_cfg_update(pruss, PRUSS_CFG_SPP, mask, set);
+}
+EXPORT_SYMBOL_GPL(pruss_cfg_xfr_enable);
+
+static void pruss_of_free_clk_provider(void *data)
+{
+	struct device_node *clk_mux_np = data;
+
+	of_clk_del_provider(clk_mux_np);
+	of_node_put(clk_mux_np);
+}
+
+static void pruss_clk_unregister_mux(void *data)
+{
+	clk_unregister_mux(data);
+}
+
+static int pruss_clk_mux_setup(struct pruss *pruss, struct clk *clk_mux,
+			       char *mux_name, struct device_node *clks_np)
+{
+	struct device_node *clk_mux_np;
+	struct device *dev = pruss->dev;
+	char *clk_mux_name;
+	unsigned int num_parents;
+	const char **parent_names;
+	void __iomem *reg;
+	u32 reg_offset;
+	int ret;
+
+	clk_mux_np = of_get_child_by_name(clks_np, mux_name);
+	if (!clk_mux_np) {
+		dev_err(dev, "%pOF is missing its '%s' node\n", clks_np,
+			mux_name);
+		return -ENODEV;
+	}
+
+	num_parents = of_clk_get_parent_count(clk_mux_np);
+	if (num_parents < 1) {
+		dev_err(dev, "mux-clock %pOF must have parents\n", clk_mux_np);
+		ret = -EINVAL;
+		goto put_clk_mux_np;
+	}
+
+	parent_names = devm_kcalloc(dev, sizeof(*parent_names), num_parents,
+				    GFP_KERNEL);
+	if (!parent_names) {
+		ret = -ENOMEM;
+		goto put_clk_mux_np;
+	}
+
+	of_clk_parent_fill(clk_mux_np, parent_names, num_parents);
+
+	clk_mux_name = devm_kasprintf(dev, GFP_KERNEL, "%s.%pOFn",
+				      dev_name(dev), clk_mux_np);
+	if (!clk_mux_name) {
+		ret = -ENOMEM;
+		goto put_clk_mux_np;
+	}
+
+	ret = of_property_read_u32(clk_mux_np, "reg", &reg_offset);
+	if (ret)
+		goto put_clk_mux_np;
+
+	reg = pruss->cfg_base + reg_offset;
+
+	clk_mux = clk_register_mux(NULL, clk_mux_name, parent_names,
+				   num_parents, 0, reg, 0, 1, 0, NULL);
+	if (IS_ERR(clk_mux)) {
+		ret = PTR_ERR(clk_mux);
+		goto put_clk_mux_np;
+	}
+
+	ret = devm_add_action_or_reset(dev, pruss_clk_unregister_mux, clk_mux);
+	if (ret) {
+		dev_err(dev, "failed to add clkmux unregister action %d", ret);
+		goto put_clk_mux_np;
+	}
+
+	ret = of_clk_add_provider(clk_mux_np, of_clk_src_simple_get, clk_mux);
+	if (ret)
+		goto put_clk_mux_np;
+
+	ret = devm_add_action_or_reset(dev, pruss_of_free_clk_provider,
+				       clk_mux_np);
+	if (ret)
+		dev_err(dev, "failed to add clkmux free action %d", ret);
+
+	return ret;
+
+put_clk_mux_np:
+	of_node_put(clk_mux_np);
+	return ret;
+}
+
+static int pruss_clk_init(struct pruss *pruss, struct device_node *cfg_node)
+{
+	struct device *dev = pruss->dev;
+	struct device_node *clks_np __free(device_node) =
+			of_get_child_by_name(cfg_node, "clocks");
+	const struct pruss_private_data *data = of_device_get_match_data(dev);
+	int ret;
+
+	if (!clks_np)
+		return dev_err_probe(dev, -ENODEV,
+				     "%pOF is missing its 'clocks' node\n",
+				     cfg_node);
+
+	if (data && data->has_core_mux_clock) {
+		ret = pruss_clk_mux_setup(pruss, pruss->core_clk_mux,
+					  "coreclk-mux", clks_np);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "failed to setup coreclk-mux\n");
+	}
+
+	ret = pruss_clk_mux_setup(pruss, pruss->iep_clk_mux, "iepclk-mux",
+				  clks_np);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to setup iepclk-mux\n");
+
+	return 0;
+}
+
+static int pruss_of_setup_memories(struct device *dev, struct pruss *pruss)
+{
+	struct device_node *np = dev_of_node(dev);
+	struct device_node *child __free(device_node) =
+			of_get_child_by_name(np, "memories");
+	const struct pruss_private_data *data = of_device_get_match_data(dev);
+	const char *mem_names[PRUSS_MEM_MAX] = { "dram0", "dram1", "shrdram2" };
+	int i;
+
+	if (!child)
+		return dev_err_probe(dev, -ENODEV,
+				     "%pOF is missing its 'memories' node\n",
+				     child);
+
+	for (i = 0; i < PRUSS_MEM_MAX; i++) {
+		struct resource res;
+		int index;
+
+		/*
+		 * On AM437x one of two PRUSS units don't contain Shared RAM,
+		 * skip it
+		 */
+		if (data && data->has_no_sharedram && i == PRUSS_MEM_SHRD_RAM2)
+			continue;
+
+		index = of_property_match_string(child, "reg-names",
+						 mem_names[i]);
+		if (index < 0)
+			return index;
+
+		if (of_address_to_resource(child, index, &res))
+			return -EINVAL;
+
+		pruss->mem_regions[i].va = devm_ioremap(dev, res.start,
+							resource_size(&res));
+		if (!pruss->mem_regions[i].va)
+			return dev_err_probe(dev, -ENOMEM,
+					     "failed to parse and map memory resource %d %s\n",
+					     i, mem_names[i]);
+		pruss->mem_regions[i].pa = res.start;
+		pruss->mem_regions[i].size = resource_size(&res);
+
+		dev_dbg(dev, "memory %8s: pa %pa size 0x%zx va %p\n",
+			mem_names[i], &pruss->mem_regions[i].pa,
+			pruss->mem_regions[i].size, pruss->mem_regions[i].va);
+	}
+
+	return 0;
+}
+
+static struct regmap_config regmap_conf = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static int pruss_cfg_of_init(struct device *dev, struct pruss *pruss)
+{
+	struct device_node *np = dev_of_node(dev);
+	struct device_node *child __free(device_node) =
+			of_get_child_by_name(np, "cfg");
+	struct resource res;
+	int ret;
+
+	if (!child)
+		return dev_err_probe(dev, -ENODEV,
+				     "%pOF is missing its 'cfg' node\n", child);
+
+	if (of_address_to_resource(child, 0, &res))
+		return -ENOMEM;
+
+	pruss->cfg_base = devm_ioremap(dev, res.start, resource_size(&res));
+	if (!pruss->cfg_base)
+		return -ENOMEM;
+
+	regmap_conf.name = kasprintf(GFP_KERNEL, "%pOFn@%llx", child,
+				     (u64)res.start);
+	regmap_conf.max_register = resource_size(&res) - 4;
+
+	pruss->cfg_regmap = devm_regmap_init_mmio(dev, pruss->cfg_base,
+						  &regmap_conf);
+	kfree(regmap_conf.name);
+	if (IS_ERR(pruss->cfg_regmap))
+		return dev_err_probe(dev, PTR_ERR(pruss->cfg_regmap),
+				     "regmap_init_mmio failed for cfg\n");
+
+	ret = pruss_clk_init(pruss, child);
+	if (ret)
+		return dev_err_probe(dev, ret, "pruss_clk_init failed\n");
+
+	return 0;
+}
+
+static int pruss_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pruss *pruss;
+	int ret;
+
+	ret = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
+	if (ret) {
+		dev_err(dev, "failed to set the DMA coherent mask");
+		return ret;
+	}
+
+	pruss = devm_kzalloc(dev, sizeof(*pruss), GFP_KERNEL);
+	if (!pruss)
+		return -ENOMEM;
+
+	pruss->dev = dev;
+	mutex_init(&pruss->lock);
+
+	ret = pruss_of_setup_memories(dev, pruss);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, pruss);
+
+	pm_runtime_enable(dev);
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
+		dev_err(dev, "couldn't enable module\n");
+		goto rpm_disable;
+	}
+
+	ret = pruss_cfg_of_init(dev, pruss);
+	if (ret < 0)
+		goto rpm_put;
+
+	ret = devm_of_platform_populate(dev);
+	if (ret) {
+		dev_err(dev, "failed to register child devices\n");
+		goto rpm_put;
+	}
+
+	return 0;
+
+rpm_put:
+	pm_runtime_put_sync(dev);
+rpm_disable:
+	pm_runtime_disable(dev);
+	return ret;
+}
+
+static void pruss_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	devm_of_platform_depopulate(dev);
+
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+}
+
+/* instance-specific driver private data */
+static const struct pruss_private_data am437x_pruss1_data = {
+	.has_no_sharedram = false,
+};
+
+static const struct pruss_private_data am437x_pruss0_data = {
+	.has_no_sharedram = true,
+};
+
+static const struct pruss_private_data am65x_j721e_pruss_data = {
+	.has_core_mux_clock = true,
+};
+
+static const struct of_device_id pruss_of_match[] = {
+	{ .compatible = "ti,am3356-pruss" },
+	{ .compatible = "ti,am4376-pruss0", .data = &am437x_pruss0_data, },
+	{ .compatible = "ti,am4376-pruss1", .data = &am437x_pruss1_data, },
+	{ .compatible = "ti,am5728-pruss" },
+	{ .compatible = "ti,k2g-pruss" },
+	{ .compatible = "ti,am654-icssg", .data = &am65x_j721e_pruss_data, },
+	{ .compatible = "ti,j721e-icssg", .data = &am65x_j721e_pruss_data, },
+	{ .compatible = "ti,am642-icssg", .data = &am65x_j721e_pruss_data, },
+	{ .compatible = "ti,am625-pruss", .data = &am65x_j721e_pruss_data, },
+	{},
+};
+MODULE_DEVICE_TABLE(of, pruss_of_match);
+
+static struct platform_driver pruss_driver = {
+	.driver = {
+		.name = "pruss",
+		.of_match_table = pruss_of_match,
+	},
+	.probe = pruss_probe,
+	.remove = pruss_remove,
+};
+module_platform_driver(pruss_driver);
+
+MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");
+MODULE_DESCRIPTION("PRU-ICSS Subsystem Driver");
+MODULE_LICENSE("GPL v2");