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>

3 files changed, 316 insertions, 0 deletions

diff --git a/drivers/pmdomain/xilinx/Kconfig b/drivers/pmdomain/xilinx/Kconfig
new file mode 100644
index 000000000..5242753d8
--- /dev/null
+++ b/drivers/pmdomain/xilinx/Kconfig
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config ZYNQMP_PM_DOMAINS
+	bool "Enable Zynq MPSoC generic PM domains"
+	default y
+	depends on PM && ZYNQMP_FIRMWARE
+	select PM_GENERIC_DOMAINS
+	help
+	  Say yes to enable device power management through PM domains
+	  If in doubt, say N.
diff --git a/drivers/pmdomain/xilinx/Makefile b/drivers/pmdomain/xilinx/Makefile
new file mode 100644
index 000000000..a706ab699
--- /dev/null
+++ b/drivers/pmdomain/xilinx/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_ZYNQMP_PM_DOMAINS)		+= zynqmp-pm-domains.o
diff --git a/drivers/pmdomain/xilinx/zynqmp-pm-domains.c b/drivers/pmdomain/xilinx/zynqmp-pm-domains.c
new file mode 100644
index 000000000..b5aedd6e3
--- /dev/null
+++ b/drivers/pmdomain/xilinx/zynqmp-pm-domains.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ZynqMP Generic PM domain support
+ *
+ *  Copyright (C) 2015-2019 Xilinx, Inc.
+ *
+ *  Davorin Mista <davorin.mista@aggios.com>
+ *  Jolly Shah <jollys@xilinx.com>
+ *  Rajan Vaja <rajan.vaja@xilinx.com>
+ */
+
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/slab.h>
+
+#include <linux/firmware/xlnx-zynqmp.h>
+
+#define ZYNQMP_NUM_DOMAINS		(100)
+
+static int min_capability;
+
+/**
+ * struct zynqmp_pm_domain - Wrapper around struct generic_pm_domain
+ * @gpd:		Generic power domain
+ * @node_id:		PM node ID corresponding to device inside PM domain
+ * @requested:		The PM node mapped to the PM domain has been requested
+ */
+struct zynqmp_pm_domain {
+	struct generic_pm_domain gpd;
+	u32 node_id;
+	bool requested;
+};
+
+#define to_zynqmp_pm_domain(pm_domain) \
+	container_of(pm_domain, struct zynqmp_pm_domain, gpd)
+
+/**
+ * zynqmp_gpd_is_active_wakeup_path() - Check if device is in wakeup source
+ *					path
+ * @dev:	Device to check for wakeup source path
+ * @not_used:	Data member (not required)
+ *
+ * This function is checks device's child hierarchy and checks if any device is
+ * set as wakeup source.
+ *
+ * Return: 1 if device is in wakeup source path else 0
+ */
+static int zynqmp_gpd_is_active_wakeup_path(struct device *dev, void *not_used)
+{
+	int may_wakeup;
+
+	may_wakeup = device_may_wakeup(dev);
+	if (may_wakeup)
+		return may_wakeup;
+
+	return device_for_each_child(dev, NULL,
+			zynqmp_gpd_is_active_wakeup_path);
+}
+
+/**
+ * zynqmp_gpd_power_on() - Power on PM domain
+ * @domain:	Generic PM domain
+ *
+ * This function is called before devices inside a PM domain are resumed, to
+ * power on PM domain.
+ *
+ * Return: 0 on success, error code otherwise
+ */
+static int zynqmp_gpd_power_on(struct generic_pm_domain *domain)
+{
+	struct zynqmp_pm_domain *pd = to_zynqmp_pm_domain(domain);
+	int ret;
+
+	ret = zynqmp_pm_set_requirement(pd->node_id,
+					ZYNQMP_PM_CAPABILITY_ACCESS,
+					ZYNQMP_PM_MAX_QOS,
+					ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+	if (ret) {
+		dev_err(&domain->dev,
+			"failed to set requirement to 0x%x for PM node id %d: %d\n",
+			ZYNQMP_PM_CAPABILITY_ACCESS, pd->node_id, ret);
+		return ret;
+	}
+
+	dev_dbg(&domain->dev, "set requirement to 0x%x for PM node id %d\n",
+		ZYNQMP_PM_CAPABILITY_ACCESS, pd->node_id);
+
+	return 0;
+}
+
+/**
+ * zynqmp_gpd_power_off() - Power off PM domain
+ * @domain:	Generic PM domain
+ *
+ * This function is called after devices inside a PM domain are suspended, to
+ * power off PM domain.
+ *
+ * Return: 0 on success, error code otherwise
+ */
+static int zynqmp_gpd_power_off(struct generic_pm_domain *domain)
+{
+	struct zynqmp_pm_domain *pd = to_zynqmp_pm_domain(domain);
+	int ret;
+	struct pm_domain_data *pdd, *tmp;
+	u32 capabilities = min_capability;
+	bool may_wakeup;
+
+	/* If domain is already released there is nothing to be done */
+	if (!pd->requested) {
+		dev_dbg(&domain->dev, "PM node id %d is already released\n",
+			pd->node_id);
+		return 0;
+	}
+
+	list_for_each_entry_safe(pdd, tmp, &domain->dev_list, list_node) {
+		/* If device is in wakeup path, set capability to WAKEUP */
+		may_wakeup = zynqmp_gpd_is_active_wakeup_path(pdd->dev, NULL);
+		if (may_wakeup) {
+			dev_dbg(pdd->dev, "device is in wakeup path in %s\n",
+				domain->name);
+			capabilities = ZYNQMP_PM_CAPABILITY_WAKEUP;
+			break;
+		}
+	}
+
+	ret = zynqmp_pm_set_requirement(pd->node_id, capabilities, 0,
+					ZYNQMP_PM_REQUEST_ACK_NO);
+	if (ret) {
+		dev_err(&domain->dev,
+			"failed to set requirement to 0x%x for PM node id %d: %d\n",
+			capabilities, pd->node_id, ret);
+		return ret;
+	}
+
+	dev_dbg(&domain->dev, "set requirement to 0x%x for PM node id %d\n",
+		capabilities, pd->node_id);
+
+	return 0;
+}
+
+/**
+ * zynqmp_gpd_attach_dev() - Attach device to the PM domain
+ * @domain:	Generic PM domain
+ * @dev:	Device to attach
+ *
+ * Return: 0 on success, error code otherwise
+ */
+static int zynqmp_gpd_attach_dev(struct generic_pm_domain *domain,
+				 struct device *dev)
+{
+	struct zynqmp_pm_domain *pd = to_zynqmp_pm_domain(domain);
+	int ret;
+
+	/* If this is not the first device to attach there is nothing to do */
+	if (domain->device_count)
+		return 0;
+
+	ret = zynqmp_pm_request_node(pd->node_id, 0, 0,
+				     ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+	if (ret) {
+		dev_err(&domain->dev, "%s request failed for node %d: %d\n",
+			domain->name, pd->node_id, ret);
+		return ret;
+	}
+
+	pd->requested = true;
+
+	dev_dbg(&domain->dev, "%s requested PM node id %d\n",
+		dev_name(dev), pd->node_id);
+
+	return 0;
+}
+
+/**
+ * zynqmp_gpd_detach_dev() - Detach device from the PM domain
+ * @domain:	Generic PM domain
+ * @dev:	Device to detach
+ */
+static void zynqmp_gpd_detach_dev(struct generic_pm_domain *domain,
+				  struct device *dev)
+{
+	struct zynqmp_pm_domain *pd = to_zynqmp_pm_domain(domain);
+	int ret;
+
+	/* If this is not the last device to detach there is nothing to do */
+	if (domain->device_count)
+		return;
+
+	ret = zynqmp_pm_release_node(pd->node_id);
+	if (ret) {
+		dev_err(&domain->dev, "failed to release PM node id %d: %d\n",
+			pd->node_id, ret);
+		return;
+	}
+
+	pd->requested = false;
+
+	dev_dbg(&domain->dev, "%s released PM node id %d\n",
+		dev_name(dev), pd->node_id);
+}
+
+static struct generic_pm_domain *zynqmp_gpd_xlate
+				(const struct of_phandle_args *genpdspec, void *data)
+{
+	struct genpd_onecell_data *genpd_data = data;
+	unsigned int i, idx = genpdspec->args[0];
+	struct zynqmp_pm_domain *pd;
+
+	pd = to_zynqmp_pm_domain(genpd_data->domains[0]);
+
+	if (genpdspec->args_count != 1)
+		return ERR_PTR(-EINVAL);
+
+	/* Check for existing pm domains */
+	for (i = 0; i < ZYNQMP_NUM_DOMAINS; i++) {
+		if (pd[i].node_id == idx)
+			goto done;
+	}
+
+	/*
+	 * Add index in empty node_id of power domain list as no existing
+	 * power domain found for current index.
+	 */
+	for (i = 0; i < ZYNQMP_NUM_DOMAINS; i++) {
+		if (pd[i].node_id == 0) {
+			pd[i].node_id = idx;
+			break;
+		}
+	}
+
+done:
+	if (!genpd_data->domains[i] || i == ZYNQMP_NUM_DOMAINS)
+		return ERR_PTR(-ENOENT);
+
+	return genpd_data->domains[i];
+}
+
+static int zynqmp_gpd_probe(struct platform_device *pdev)
+{
+	int i;
+	struct genpd_onecell_data *zynqmp_pd_data;
+	struct generic_pm_domain **domains;
+	struct zynqmp_pm_domain *pd;
+	struct device *dev = &pdev->dev;
+
+	pd = devm_kcalloc(dev, ZYNQMP_NUM_DOMAINS, sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return -ENOMEM;
+
+	zynqmp_pd_data = devm_kzalloc(dev, sizeof(*zynqmp_pd_data), GFP_KERNEL);
+	if (!zynqmp_pd_data)
+		return -ENOMEM;
+
+	zynqmp_pd_data->xlate = zynqmp_gpd_xlate;
+
+	domains = devm_kcalloc(dev, ZYNQMP_NUM_DOMAINS, sizeof(*domains),
+			       GFP_KERNEL);
+	if (!domains)
+		return -ENOMEM;
+
+	if (!of_device_is_compatible(dev->parent->of_node,
+				     "xlnx,zynqmp-firmware"))
+		min_capability = ZYNQMP_PM_CAPABILITY_UNUSABLE;
+
+	for (i = 0; i < ZYNQMP_NUM_DOMAINS; i++, pd++) {
+		pd->node_id = 0;
+		pd->gpd.name = kasprintf(GFP_KERNEL, "domain%d", i);
+		pd->gpd.power_off = zynqmp_gpd_power_off;
+		pd->gpd.power_on = zynqmp_gpd_power_on;
+		pd->gpd.attach_dev = zynqmp_gpd_attach_dev;
+		pd->gpd.detach_dev = zynqmp_gpd_detach_dev;
+
+		domains[i] = &pd->gpd;
+
+		/* Mark all PM domains as initially powered off */
+		pm_genpd_init(&pd->gpd, NULL, true);
+	}
+
+	zynqmp_pd_data->domains = domains;
+	zynqmp_pd_data->num_domains = ZYNQMP_NUM_DOMAINS;
+	of_genpd_add_provider_onecell(dev->parent->of_node, zynqmp_pd_data);
+
+	return 0;
+}
+
+static void zynqmp_gpd_remove(struct platform_device *pdev)
+{
+	of_genpd_del_provider(pdev->dev.parent->of_node);
+}
+
+static struct platform_driver zynqmp_power_domain_driver = {
+	.driver	= {
+		.name = "zynqmp_power_controller",
+	},
+	.probe = zynqmp_gpd_probe,
+	.remove = zynqmp_gpd_remove,
+};
+module_platform_driver(zynqmp_power_domain_driver);
+
+MODULE_ALIAS("platform:zynqmp_power_controller");