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>

2 files changed, 456 insertions, 0 deletions

diff --git a/drivers/soc/dove/Makefile b/drivers/soc/dove/Makefile
new file mode 100644
index 000000000..daf4549ec
--- /dev/null
+++ b/drivers/soc/dove/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-y		+= pmu.o
diff --git a/drivers/soc/dove/pmu.c b/drivers/soc/dove/pmu.c
new file mode 100644
index 000000000..611caaeed
--- /dev/null
+++ b/drivers/soc/dove/pmu.c
@@ -0,0 +1,454 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Marvell Dove PMU support
+ */
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/reset.h>
+#include <linux/reset-controller.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/soc/dove/pmu.h>
+#include <linux/spinlock.h>
+
+#define NR_PMU_IRQS		7
+
+#define PMC_SW_RST		0x30
+#define PMC_IRQ_CAUSE		0x50
+#define PMC_IRQ_MASK		0x54
+
+#define PMU_PWR			0x10
+#define PMU_ISO			0x58
+
+struct pmu_data {
+	spinlock_t lock;
+	struct device_node *of_node;
+	void __iomem *pmc_base;
+	void __iomem *pmu_base;
+	struct irq_chip_generic *irq_gc;
+	struct irq_domain *irq_domain;
+#ifdef CONFIG_RESET_CONTROLLER
+	struct reset_controller_dev reset;
+#endif
+};
+
+/*
+ * The PMU contains a register to reset various subsystems within the
+ * SoC.  Export this as a reset controller.
+ */
+#ifdef CONFIG_RESET_CONTROLLER
+#define rcdev_to_pmu(rcdev) container_of(rcdev, struct pmu_data, reset)
+
+static int pmu_reset_reset(struct reset_controller_dev *rc, unsigned long id)
+{
+	struct pmu_data *pmu = rcdev_to_pmu(rc);
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&pmu->lock, flags);
+	val = readl_relaxed(pmu->pmc_base + PMC_SW_RST);
+	writel_relaxed(val & ~BIT(id), pmu->pmc_base + PMC_SW_RST);
+	writel_relaxed(val | BIT(id), pmu->pmc_base + PMC_SW_RST);
+	spin_unlock_irqrestore(&pmu->lock, flags);
+
+	return 0;
+}
+
+static int pmu_reset_assert(struct reset_controller_dev *rc, unsigned long id)
+{
+	struct pmu_data *pmu = rcdev_to_pmu(rc);
+	unsigned long flags;
+	u32 val = ~BIT(id);
+
+	spin_lock_irqsave(&pmu->lock, flags);
+	val &= readl_relaxed(pmu->pmc_base + PMC_SW_RST);
+	writel_relaxed(val, pmu->pmc_base + PMC_SW_RST);
+	spin_unlock_irqrestore(&pmu->lock, flags);
+
+	return 0;
+}
+
+static int pmu_reset_deassert(struct reset_controller_dev *rc, unsigned long id)
+{
+	struct pmu_data *pmu = rcdev_to_pmu(rc);
+	unsigned long flags;
+	u32 val = BIT(id);
+
+	spin_lock_irqsave(&pmu->lock, flags);
+	val |= readl_relaxed(pmu->pmc_base + PMC_SW_RST);
+	writel_relaxed(val, pmu->pmc_base + PMC_SW_RST);
+	spin_unlock_irqrestore(&pmu->lock, flags);
+
+	return 0;
+}
+
+static const struct reset_control_ops pmu_reset_ops = {
+	.reset = pmu_reset_reset,
+	.assert = pmu_reset_assert,
+	.deassert = pmu_reset_deassert,
+};
+
+static struct reset_controller_dev pmu_reset __initdata = {
+	.ops = &pmu_reset_ops,
+	.owner = THIS_MODULE,
+	.nr_resets = 32,
+};
+
+static void __init pmu_reset_init(struct pmu_data *pmu)
+{
+	int ret;
+
+	pmu->reset = pmu_reset;
+	pmu->reset.of_node = pmu->of_node;
+
+	ret = reset_controller_register(&pmu->reset);
+	if (ret)
+		pr_err("pmu: %s failed: %d\n", "reset_controller_register", ret);
+}
+#else
+static void __init pmu_reset_init(struct pmu_data *pmu)
+{
+}
+#endif
+
+struct pmu_domain {
+	struct pmu_data *pmu;
+	u32 pwr_mask;
+	u32 rst_mask;
+	u32 iso_mask;
+	struct generic_pm_domain base;
+};
+
+#define to_pmu_domain(dom) container_of(dom, struct pmu_domain, base)
+
+/*
+ * This deals with the "old" Marvell sequence of bringing a power domain
+ * down/up, which is: apply power, release reset, disable isolators.
+ *
+ * Later devices apparantly use a different sequence: power up, disable
+ * isolators, assert repair signal, enable SRMA clock, enable AXI clock,
+ * enable module clock, deassert reset.
+ *
+ * Note: reading the assembly, it seems that the IO accessors have an
+ * unfortunate side-effect - they cause memory already read into registers
+ * for the if () to be re-read for the bit-set or bit-clear operation.
+ * The code is written to avoid this.
+ */
+static int pmu_domain_power_off(struct generic_pm_domain *domain)
+{
+	struct pmu_domain *pmu_dom = to_pmu_domain(domain);
+	struct pmu_data *pmu = pmu_dom->pmu;
+	unsigned long flags;
+	unsigned int val;
+	void __iomem *pmu_base = pmu->pmu_base;
+	void __iomem *pmc_base = pmu->pmc_base;
+
+	spin_lock_irqsave(&pmu->lock, flags);
+
+	/* Enable isolators */
+	if (pmu_dom->iso_mask) {
+		val = ~pmu_dom->iso_mask;
+		val &= readl_relaxed(pmu_base + PMU_ISO);
+		writel_relaxed(val, pmu_base + PMU_ISO);
+	}
+
+	/* Reset unit */
+	if (pmu_dom->rst_mask) {
+		val = ~pmu_dom->rst_mask;
+		val &= readl_relaxed(pmc_base + PMC_SW_RST);
+		writel_relaxed(val, pmc_base + PMC_SW_RST);
+	}
+
+	/* Power down */
+	val = readl_relaxed(pmu_base + PMU_PWR) | pmu_dom->pwr_mask;
+	writel_relaxed(val, pmu_base + PMU_PWR);
+
+	spin_unlock_irqrestore(&pmu->lock, flags);
+
+	return 0;
+}
+
+static int pmu_domain_power_on(struct generic_pm_domain *domain)
+{
+	struct pmu_domain *pmu_dom = to_pmu_domain(domain);
+	struct pmu_data *pmu = pmu_dom->pmu;
+	unsigned long flags;
+	unsigned int val;
+	void __iomem *pmu_base = pmu->pmu_base;
+	void __iomem *pmc_base = pmu->pmc_base;
+
+	spin_lock_irqsave(&pmu->lock, flags);
+
+	/* Power on */
+	val = ~pmu_dom->pwr_mask & readl_relaxed(pmu_base + PMU_PWR);
+	writel_relaxed(val, pmu_base + PMU_PWR);
+
+	/* Release reset */
+	if (pmu_dom->rst_mask) {
+		val = pmu_dom->rst_mask;
+		val |= readl_relaxed(pmc_base + PMC_SW_RST);
+		writel_relaxed(val, pmc_base + PMC_SW_RST);
+	}
+
+	/* Disable isolators */
+	if (pmu_dom->iso_mask) {
+		val = pmu_dom->iso_mask;
+		val |= readl_relaxed(pmu_base + PMU_ISO);
+		writel_relaxed(val, pmu_base + PMU_ISO);
+	}
+
+	spin_unlock_irqrestore(&pmu->lock, flags);
+
+	return 0;
+}
+
+static void __pmu_domain_register(struct pmu_domain *domain,
+	struct device_node *np)
+{
+	unsigned int val = readl_relaxed(domain->pmu->pmu_base + PMU_PWR);
+
+	domain->base.power_off = pmu_domain_power_off;
+	domain->base.power_on = pmu_domain_power_on;
+
+	pm_genpd_init(&domain->base, NULL, !(val & domain->pwr_mask));
+
+	if (np)
+		of_genpd_add_provider_simple(np, &domain->base);
+}
+
+/* PMU IRQ controller */
+static void pmu_irq_handler(struct irq_desc *desc)
+{
+	struct pmu_data *pmu = irq_desc_get_handler_data(desc);
+	struct irq_chip_generic *gc = pmu->irq_gc;
+	struct irq_domain *domain = pmu->irq_domain;
+	void __iomem *base = gc->reg_base;
+	u32 stat = readl_relaxed(base + PMC_IRQ_CAUSE) & gc->mask_cache;
+	u32 done = ~0;
+
+	if (stat == 0) {
+		handle_bad_irq(desc);
+		return;
+	}
+
+	while (stat) {
+		u32 hwirq = fls(stat) - 1;
+
+		stat &= ~(1 << hwirq);
+		done &= ~(1 << hwirq);
+
+		generic_handle_irq(irq_find_mapping(domain, hwirq));
+	}
+
+	/*
+	 * The PMU mask register is not RW0C: it is RW.  This means that
+	 * the bits take whatever value is written to them; if you write
+	 * a '1', you will set the interrupt.
+	 *
+	 * Unfortunately this means there is NO race free way to clear
+	 * these interrupts.
+	 *
+	 * So, let's structure the code so that the window is as small as
+	 * possible.
+	 */
+	guard(raw_spinlock)(&gc->lock);
+	done &= readl_relaxed(base + PMC_IRQ_CAUSE);
+	writel_relaxed(done, base + PMC_IRQ_CAUSE);
+}
+
+static int __init dove_init_pmu_irq(struct pmu_data *pmu, int irq)
+{
+	const char *name = "pmu_irq";
+	struct irq_chip_generic *gc;
+	struct irq_domain *domain;
+	int ret;
+
+	/* mask and clear all interrupts */
+	writel(0, pmu->pmc_base + PMC_IRQ_MASK);
+	writel(0, pmu->pmc_base + PMC_IRQ_CAUSE);
+
+	domain = irq_domain_create_linear(of_fwnode_handle(pmu->of_node), NR_PMU_IRQS,
+					  &irq_generic_chip_ops, NULL);
+	if (!domain) {
+		pr_err("%s: unable to add irq domain\n", name);
+		return -ENOMEM;
+	}
+
+	ret = irq_alloc_domain_generic_chips(domain, NR_PMU_IRQS, 1, name,
+					     handle_level_irq,
+					     IRQ_NOREQUEST | IRQ_NOPROBE, 0,
+					     IRQ_GC_INIT_MASK_CACHE);
+	if (ret) {
+		pr_err("%s: unable to alloc irq domain gc: %d\n", name, ret);
+		irq_domain_remove(domain);
+		return ret;
+	}
+
+	gc = irq_get_domain_generic_chip(domain, 0);
+	gc->reg_base = pmu->pmc_base;
+	gc->chip_types[0].regs.mask = PMC_IRQ_MASK;
+	gc->chip_types[0].chip.irq_mask = irq_gc_mask_clr_bit;
+	gc->chip_types[0].chip.irq_unmask = irq_gc_mask_set_bit;
+
+	pmu->irq_domain = domain;
+	pmu->irq_gc = gc;
+
+	irq_set_handler_data(irq, pmu);
+	irq_set_chained_handler(irq, pmu_irq_handler);
+
+	return 0;
+}
+
+int __init dove_init_pmu_legacy(const struct dove_pmu_initdata *initdata)
+{
+	const struct dove_pmu_domain_initdata *domain_initdata;
+	struct pmu_data *pmu;
+	int ret;
+
+	pmu = kzalloc_obj(*pmu);
+	if (!pmu)
+		return -ENOMEM;
+
+	spin_lock_init(&pmu->lock);
+	pmu->pmc_base = initdata->pmc_base;
+	pmu->pmu_base = initdata->pmu_base;
+
+	pmu_reset_init(pmu);
+	for (domain_initdata = initdata->domains; domain_initdata->name;
+	     domain_initdata++) {
+		struct pmu_domain *domain;
+
+		domain = kzalloc_obj(*domain);
+		if (domain) {
+			domain->pmu = pmu;
+			domain->pwr_mask = domain_initdata->pwr_mask;
+			domain->rst_mask = domain_initdata->rst_mask;
+			domain->iso_mask = domain_initdata->iso_mask;
+			domain->base.name = domain_initdata->name;
+
+			__pmu_domain_register(domain, NULL);
+		}
+	}
+
+	ret = dove_init_pmu_irq(pmu, initdata->irq);
+	if (ret)
+		pr_err("dove_init_pmu_irq() failed: %d\n", ret);
+
+	if (pmu->irq_domain)
+		irq_domain_associate_many(pmu->irq_domain,
+					  initdata->irq_domain_start,
+					  0, NR_PMU_IRQS);
+
+	return 0;
+}
+
+/*
+ * pmu: power-manager@d0000 {
+ *	compatible = "marvell,dove-pmu";
+ *	reg = <0xd0000 0x8000> <0xd8000 0x8000>;
+ *	interrupts = <33>;
+ *	interrupt-controller;
+ *	#reset-cells = 1;
+ *	vpu_domain: vpu-domain {
+ *		#power-domain-cells = <0>;
+ *		marvell,pmu_pwr_mask = <0x00000008>;
+ *		marvell,pmu_iso_mask = <0x00000001>;
+ *		resets = <&pmu 16>;
+ *	};
+ *	gpu_domain: gpu-domain {
+ *		#power-domain-cells = <0>;
+ *		marvell,pmu_pwr_mask = <0x00000004>;
+ *		marvell,pmu_iso_mask = <0x00000002>;
+ *		resets = <&pmu 18>;
+ *	};
+ * };
+ */
+int __init dove_init_pmu(void)
+{
+	struct device_node *np_pmu, *domains_node;
+	struct pmu_data *pmu;
+	int ret, parent_irq;
+
+	/* Lookup the PMU node */
+	np_pmu = of_find_compatible_node(NULL, NULL, "marvell,dove-pmu");
+	if (!np_pmu)
+		return 0;
+
+	domains_node = of_get_child_by_name(np_pmu, "domains");
+	if (!domains_node) {
+		pr_err("%pOFn: failed to find domains sub-node\n", np_pmu);
+		return 0;
+	}
+
+	pmu = kzalloc_obj(*pmu);
+	if (!pmu)
+		return -ENOMEM;
+
+	spin_lock_init(&pmu->lock);
+	pmu->of_node = np_pmu;
+	pmu->pmc_base = of_iomap(pmu->of_node, 0);
+	pmu->pmu_base = of_iomap(pmu->of_node, 1);
+	if (!pmu->pmc_base || !pmu->pmu_base) {
+		pr_err("%pOFn: failed to map PMU\n", np_pmu);
+		iounmap(pmu->pmu_base);
+		iounmap(pmu->pmc_base);
+		kfree(pmu);
+		return -ENOMEM;
+	}
+
+	pmu_reset_init(pmu);
+
+	for_each_available_child_of_node_scoped(domains_node, np) {
+		struct of_phandle_args args;
+		struct pmu_domain *domain;
+
+		domain = kzalloc_obj(*domain);
+		if (!domain)
+			break;
+
+		domain->pmu = pmu;
+		domain->base.name = kasprintf(GFP_KERNEL, "%pOFn", np);
+		if (!domain->base.name) {
+			kfree(domain);
+			break;
+		}
+
+		of_property_read_u32(np, "marvell,pmu_pwr_mask",
+				     &domain->pwr_mask);
+		of_property_read_u32(np, "marvell,pmu_iso_mask",
+				     &domain->iso_mask);
+
+		/*
+		 * We parse the reset controller property directly here
+		 * to ensure that we can operate when the reset controller
+		 * support is not configured into the kernel.
+		 */
+		ret = of_parse_phandle_with_args(np, "resets", "#reset-cells",
+						 0, &args);
+		if (ret == 0) {
+			if (args.np == pmu->of_node)
+				domain->rst_mask = BIT(args.args[0]);
+			of_node_put(args.np);
+		}
+
+		__pmu_domain_register(domain, np);
+	}
+
+	/* Loss of the interrupt controller is not a fatal error. */
+	parent_irq = irq_of_parse_and_map(pmu->of_node, 0);
+	if (!parent_irq) {
+		pr_err("%pOFn: no interrupt specified\n", np_pmu);
+	} else {
+		ret = dove_init_pmu_irq(pmu, parent_irq);
+		if (ret)
+			pr_err("dove_init_pmu_irq() failed: %d\n", ret);
+	}
+
+	return 0;
+}