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, 343 insertions, 0 deletions

diff --git a/drivers/pinctrl/berlin/berlin.c b/drivers/pinctrl/berlin/berlin.c
new file mode 100644
index 000000000..7971339e2
--- /dev/null
+++ b/drivers/pinctrl/berlin/berlin.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Marvell Berlin SoC pinctrl core driver
+ *
+ * Copyright (C) 2014 Marvell Technology Group Ltd.
+ *
+ * Antoine Ténart <antoine.tenart@free-electrons.com>
+ */
+
+#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_device.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include "../core.h"
+#include "../pinctrl-utils.h"
+#include "berlin.h"
+
+struct berlin_pinctrl {
+	struct regmap *regmap;
+	struct device *dev;
+	const struct berlin_pinctrl_desc *desc;
+	struct pinfunction *functions;
+	unsigned nfunctions;
+	struct pinctrl_dev *pctrl_dev;
+};
+
+static int berlin_pinctrl_get_group_count(struct pinctrl_dev *pctrl_dev)
+{
+	struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
+
+	return pctrl->desc->ngroups;
+}
+
+static const char *berlin_pinctrl_get_group_name(struct pinctrl_dev *pctrl_dev,
+						 unsigned group)
+{
+	struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
+
+	return pctrl->desc->groups[group].name;
+}
+
+static int berlin_pinctrl_dt_node_to_map(struct pinctrl_dev *pctrl_dev,
+					 struct device_node *node,
+					 struct pinctrl_map **map,
+					 unsigned *num_maps)
+{
+	struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
+	struct property *prop;
+	const char *function_name, *group_name;
+	unsigned reserved_maps = 0;
+	int ret, ngroups;
+
+	*map = NULL;
+	*num_maps = 0;
+
+	ret = of_property_read_string(node, "function", &function_name);
+	if (ret) {
+		dev_err(pctrl->dev,
+			"missing function property in node %pOFn\n", node);
+		return -EINVAL;
+	}
+
+	ngroups = of_property_count_strings(node, "groups");
+	if (ngroups < 0) {
+		dev_err(pctrl->dev,
+			"missing groups property in node %pOFn\n", node);
+		return -EINVAL;
+	}
+
+	ret = pinctrl_utils_reserve_map(pctrl_dev, map, &reserved_maps,
+					num_maps, ngroups);
+	if (ret) {
+		dev_err(pctrl->dev, "can't reserve map: %d\n", ret);
+		return ret;
+	}
+
+	of_property_for_each_string(node, "groups", prop, group_name) {
+		ret = pinctrl_utils_add_map_mux(pctrl_dev, map, &reserved_maps,
+						num_maps, group_name,
+						function_name);
+		if (ret) {
+			dev_err(pctrl->dev, "can't add map: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct pinctrl_ops berlin_pinctrl_ops = {
+	.get_groups_count	= berlin_pinctrl_get_group_count,
+	.get_group_name		= berlin_pinctrl_get_group_name,
+	.dt_node_to_map		= berlin_pinctrl_dt_node_to_map,
+	.dt_free_map		= pinctrl_utils_free_map,
+};
+
+static int berlin_pinmux_get_functions_count(struct pinctrl_dev *pctrl_dev)
+{
+	struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
+
+	return pctrl->nfunctions;
+}
+
+static const char *berlin_pinmux_get_function_name(struct pinctrl_dev *pctrl_dev,
+						   unsigned function)
+{
+	struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
+
+	return pctrl->functions[function].name;
+}
+
+static int berlin_pinmux_get_function_groups(struct pinctrl_dev *pctrl_dev,
+					     unsigned function,
+					     const char * const **groups,
+					     unsigned * const ngroups)
+{
+	struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
+
+	*groups = pctrl->functions[function].groups;
+	*ngroups = pctrl->functions[function].ngroups;
+
+	return 0;
+}
+
+static struct berlin_desc_function *
+berlin_pinctrl_find_function_by_name(struct berlin_pinctrl *pctrl,
+				     const struct berlin_desc_group *group,
+				     const char *fname)
+{
+	struct berlin_desc_function *function = group->functions;
+
+	while (function->name) {
+		if (!strcmp(function->name, fname))
+			return function;
+
+		function++;
+	}
+
+	return NULL;
+}
+
+static int berlin_pinmux_set(struct pinctrl_dev *pctrl_dev,
+			     unsigned function,
+			     unsigned group)
+{
+	struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
+	const struct berlin_desc_group *group_desc = pctrl->desc->groups + group;
+	struct pinfunction *func = pctrl->functions + function;
+	struct berlin_desc_function *function_desc =
+		berlin_pinctrl_find_function_by_name(pctrl, group_desc,
+						     func->name);
+	u32 mask, val;
+
+	if (!function_desc)
+		return -EINVAL;
+
+	mask = GENMASK(group_desc->lsb + group_desc->bit_width - 1,
+		       group_desc->lsb);
+	val = function_desc->muxval << group_desc->lsb;
+	regmap_update_bits(pctrl->regmap, group_desc->offset, mask, val);
+
+	return 0;
+}
+
+static const struct pinmux_ops berlin_pinmux_ops = {
+	.get_functions_count	= &berlin_pinmux_get_functions_count,
+	.get_function_name	= &berlin_pinmux_get_function_name,
+	.get_function_groups	= &berlin_pinmux_get_function_groups,
+	.set_mux		= &berlin_pinmux_set,
+};
+
+static int berlin_pinctrl_add_function(struct berlin_pinctrl *pctrl,
+				       const char *name)
+{
+	struct pinfunction *function = pctrl->functions;
+
+	while (function->name) {
+		if (!strcmp(function->name, name)) {
+			function->ngroups++;
+			return -EEXIST;
+		}
+		function++;
+	}
+
+	function->name = name;
+	function->ngroups = 1;
+
+	pctrl->nfunctions++;
+
+	return 0;
+}
+
+static int berlin_pinctrl_build_state(struct platform_device *pdev)
+{
+	struct berlin_pinctrl *pctrl = platform_get_drvdata(pdev);
+	const struct berlin_desc_group *desc_group;
+	const struct berlin_desc_function *desc_function;
+	int i, max_functions = 0;
+	struct pinfunction *new_functions;
+
+	pctrl->nfunctions = 0;
+
+	for (i = 0; i < pctrl->desc->ngroups; i++) {
+		desc_group = pctrl->desc->groups + i;
+		/* compute the maximum number of functions a group can have */
+		max_functions += 1 << (desc_group->bit_width + 1);
+	}
+
+	/* we will reallocate later */
+	pctrl->functions = kzalloc_objs(*pctrl->functions, max_functions);
+	if (!pctrl->functions)
+		return -ENOMEM;
+
+	/* register all functions */
+	for (i = 0; i < pctrl->desc->ngroups; i++) {
+		desc_group = pctrl->desc->groups + i;
+		desc_function = desc_group->functions;
+
+		while (desc_function->name) {
+			berlin_pinctrl_add_function(pctrl, desc_function->name);
+			desc_function++;
+		}
+	}
+
+	new_functions = krealloc(pctrl->functions,
+				    pctrl->nfunctions * sizeof(*pctrl->functions),
+				    GFP_KERNEL);
+	if (!new_functions) {
+		kfree(pctrl->functions);
+		return -ENOMEM;
+	}
+
+	pctrl->functions = new_functions;
+	/* map functions to theirs groups */
+	for (i = 0; i < pctrl->desc->ngroups; i++) {
+		desc_group = pctrl->desc->groups + i;
+		desc_function = desc_group->functions;
+
+		while (desc_function->name) {
+			struct pinfunction *function = pctrl->functions;
+			const char **groups;
+			bool found = false;
+
+			while (function->name) {
+				if (!strcmp(desc_function->name, function->name)) {
+					found = true;
+					break;
+				}
+				function++;
+			}
+
+			if (!found) {
+				kfree(pctrl->functions);
+				return -EINVAL;
+			}
+
+			if (!function->groups) {
+				function->groups =
+					devm_kcalloc(&pdev->dev,
+						     function->ngroups,
+						     sizeof(*function->groups),
+						     GFP_KERNEL);
+				if (!function->groups) {
+					kfree(pctrl->functions);
+					return -ENOMEM;
+				}
+			}
+
+			groups = (const char **)function->groups;
+			while (*groups)
+				groups++;
+
+			*groups = desc_group->name;
+
+			desc_function++;
+		}
+	}
+
+	return 0;
+}
+
+static const struct pinctrl_desc berlin_pctrl_desc = {
+	.name		= "berlin-pinctrl",
+	.pctlops	= &berlin_pinctrl_ops,
+	.pmxops		= &berlin_pinmux_ops,
+	.owner		= THIS_MODULE,
+};
+
+int berlin_pinctrl_probe_regmap(struct platform_device *pdev,
+				const struct berlin_pinctrl_desc *desc,
+				struct regmap *regmap)
+{
+	struct device *dev = &pdev->dev;
+	struct berlin_pinctrl *pctrl;
+	int ret;
+
+	pctrl = devm_kzalloc(dev, sizeof(*pctrl), GFP_KERNEL);
+	if (!pctrl)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, pctrl);
+
+	pctrl->regmap = regmap;
+	pctrl->dev = &pdev->dev;
+	pctrl->desc = desc;
+
+	ret = berlin_pinctrl_build_state(pdev);
+	if (ret) {
+		dev_err(dev, "cannot build driver state: %d\n", ret);
+		return ret;
+	}
+
+	pctrl->pctrl_dev = devm_pinctrl_register(dev, &berlin_pctrl_desc,
+						 pctrl);
+	if (IS_ERR(pctrl->pctrl_dev)) {
+		dev_err(dev, "failed to register pinctrl driver\n");
+		return PTR_ERR(pctrl->pctrl_dev);
+	}
+
+	return 0;
+}
+
+int berlin_pinctrl_probe(struct platform_device *pdev,
+			 const struct berlin_pinctrl_desc *desc)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *parent_np = of_get_parent(dev->of_node);
+	struct regmap *regmap = syscon_node_to_regmap(parent_np);
+
+	of_node_put(parent_np);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	return berlin_pinctrl_probe_regmap(pdev, desc, regmap);
+}