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>

4 files changed, 447 insertions, 0 deletions

diff --git a/drivers/soc/loongson/Kconfig b/drivers/soc/loongson/Kconfig
new file mode 100644
index 000000000..368344943
--- /dev/null
+++ b/drivers/soc/loongson/Kconfig
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Loongson-2 series SoC drivers
+#
+
+config LOONGSON2_GUTS
+	tristate "Loongson-2 SoC Global UtiliTieS (GUTS) register block"
+	depends on LOONGARCH || COMPILE_TEST
+	select SOC_BUS
+	help
+	 The global utilities block controls PCIE device enabling, alternate
+	 function selection for multiplexed signals, consistency of HDA, USB
+	 and PCIE, configuration of memory controller, rtc controller, lio
+	 controller, and clock control. This patch adds a driver to manage
+	 and access global utilities block for LoongArch architecture Loongson-2
+	 SoCs. Initially only reading SVR and registering soc device are
+	 supported. Other guts accesses, such as reading firmware configuration
+	 by default, should eventually be added into this driver as well.
+
+config LOONGSON2_PM
+	bool "Loongson-2 SoC Power Management Controller Driver"
+	depends on LOONGARCH && OF
+	depends on INPUT=y
+	help
+	  The Loongson-2's power management controller was ACPI, supports ACPI
+	  S2Idle (Suspend To Idle), ACPI S3 (Suspend To RAM), ACPI S4 (Suspend To
+	  Disk), ACPI S5 (Soft Shutdown) and supports multiple wake-up methods
+	  (USB, GMAC, PWRBTN, etc.). This driver was to add power management
+	  controller support that base on dts for Loongson-2 series SoCs.
diff --git a/drivers/soc/loongson/Makefile b/drivers/soc/loongson/Makefile
new file mode 100644
index 000000000..4118f50f5
--- /dev/null
+++ b/drivers/soc/loongson/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Makefile for the Linux Kernel SoC Loongson-2 specific device drivers
+#
+
+obj-$(CONFIG_LOONGSON2_GUTS)		+= loongson2_guts.o
+obj-$(CONFIG_LOONGSON2_PM)		+= loongson2_pm.o
diff --git a/drivers/soc/loongson/loongson2_guts.c b/drivers/soc/loongson/loongson2_guts.c
new file mode 100644
index 000000000..16913c3ef
--- /dev/null
+++ b/drivers/soc/loongson/loongson2_guts.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Author: Yinbo Zhu <zhuyinbo@loongson.cn>
+ * Copyright (C) 2022-2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/of_fdt.h>
+#include <linux/sys_soc.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+
+static struct soc_device_attribute soc_dev_attr;
+static struct soc_device *soc_dev;
+
+/*
+ * Global Utility Registers.
+ *
+ * Not all registers defined in this structure are available on all chips, so
+ * you are expected to know whether a given register actually exists on your
+ * chip before you access it.
+ *
+ * Also, some registers are similar on different chips but have slightly
+ * different names.  In these cases, one name is chosen to avoid extraneous
+ * #ifdefs.
+ */
+struct scfg_guts {
+	u32     svr;            /* Version Register */
+	u8      res0[4];
+	u16     feature;        /* Feature Register */
+	u32     vendor;         /* Vendor Register */
+	u8      res1[6];
+	u32     id;
+	u8      res2[0x3ff8 - 0x18];
+	u32     chip;
+};
+
+static struct guts {
+	struct scfg_guts __iomem *regs;
+	bool little_endian;
+} *guts;
+
+struct loongson2_soc_die_attr {
+	char	*die;
+	u32	svr;
+	u32	mask;
+};
+
+/* SoC die attribute definition for Loongson-2 platform */
+static const struct loongson2_soc_die_attr loongson2_soc_die[] = {
+
+	/*
+	 * LoongArch-based SoCs Loongson-2 Series
+	 */
+
+	/* Die: 2k1000, SoC: 2k1000 */
+	{ .die		= "2K1000",
+	  .svr		= 0x00000013,
+	  .mask		= 0x000000ff,
+	},
+	{ },
+};
+
+static const struct loongson2_soc_die_attr *loongson2_soc_die_match(
+	u32 svr, const struct loongson2_soc_die_attr *matches)
+{
+	while (matches->svr) {
+		if (matches->svr == (svr & matches->mask))
+			return matches;
+		matches++;
+	}
+
+	return NULL;
+}
+
+static u32 loongson2_guts_get_svr(void)
+{
+	u32 svr = 0;
+
+	if (!guts || !guts->regs)
+		return svr;
+
+	if (guts->little_endian)
+		svr = ioread32(&guts->regs->svr);
+	else
+		svr = ioread32be(&guts->regs->svr);
+
+	return svr;
+}
+
+static int loongson2_guts_probe(struct platform_device *pdev)
+{
+	struct device_node *root, *np = pdev->dev.of_node;
+	struct device *dev = &pdev->dev;
+	const struct loongson2_soc_die_attr *soc_die;
+	const char *machine;
+	u32 svr;
+
+	/* Initialize guts */
+	guts = devm_kzalloc(dev, sizeof(*guts), GFP_KERNEL);
+	if (!guts)
+		return -ENOMEM;
+
+	guts->little_endian = of_property_read_bool(np, "little-endian");
+
+	guts->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(guts->regs))
+		return PTR_ERR(guts->regs);
+
+	/* Register soc device */
+	root = of_find_node_by_path("/");
+	if (of_property_read_string(root, "model", &machine))
+		of_property_read_string_index(root, "compatible", 0, &machine);
+	of_node_put(root);
+	if (machine) {
+		soc_dev_attr.machine = devm_kstrdup(dev, machine, GFP_KERNEL);
+		if (!soc_dev_attr.machine)
+			return -ENOMEM;
+	}
+
+	svr = loongson2_guts_get_svr();
+	soc_die = loongson2_soc_die_match(svr, loongson2_soc_die);
+	if (soc_die) {
+		soc_dev_attr.family = devm_kasprintf(dev, GFP_KERNEL,
+						     "Loongson %s", soc_die->die);
+	} else {
+		soc_dev_attr.family = devm_kasprintf(dev, GFP_KERNEL, "Loongson");
+	}
+	if (!soc_dev_attr.family)
+		return -ENOMEM;
+	soc_dev_attr.soc_id = devm_kasprintf(dev, GFP_KERNEL,
+					     "svr:0x%08x", svr);
+	if (!soc_dev_attr.soc_id)
+		return -ENOMEM;
+	soc_dev_attr.revision = devm_kasprintf(dev, GFP_KERNEL, "%d.%d",
+					       (svr >>  4) & 0xf, svr & 0xf);
+	if (!soc_dev_attr.revision)
+		return -ENOMEM;
+
+	soc_dev = soc_device_register(&soc_dev_attr);
+	if (IS_ERR(soc_dev))
+		return PTR_ERR(soc_dev);
+
+	pr_info("Machine: %s\n", soc_dev_attr.machine);
+	pr_info("SoC family: %s\n", soc_dev_attr.family);
+	pr_info("SoC ID: %s, Revision: %s\n",
+		soc_dev_attr.soc_id, soc_dev_attr.revision);
+
+	return 0;
+}
+
+static void loongson2_guts_remove(struct platform_device *dev)
+{
+	soc_device_unregister(soc_dev);
+}
+
+/*
+ * Table for matching compatible strings, for device tree
+ * guts node, for Loongson-2 SoCs.
+ */
+static const struct of_device_id loongson2_guts_of_match[] = {
+	{ .compatible = "loongson,ls2k-chipid", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, loongson2_guts_of_match);
+
+static struct platform_driver loongson2_guts_driver = {
+	.driver = {
+		.name = "loongson2-guts",
+		.of_match_table = loongson2_guts_of_match,
+	},
+	.probe = loongson2_guts_probe,
+	.remove = loongson2_guts_remove,
+};
+
+static int __init loongson2_guts_init(void)
+{
+	return platform_driver_register(&loongson2_guts_driver);
+}
+core_initcall(loongson2_guts_init);
+
+static void __exit loongson2_guts_exit(void)
+{
+	platform_driver_unregister(&loongson2_guts_driver);
+}
+module_exit(loongson2_guts_exit);
+
+MODULE_DESCRIPTION("Loongson2 GUTS driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/soc/loongson/loongson2_pm.c b/drivers/soc/loongson/loongson2_pm.c
new file mode 100644
index 000000000..b8e5e1e35
--- /dev/null
+++ b/drivers/soc/loongson/loongson2_pm.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Loongson-2 PM Support
+ *
+ * Copyright (C) 2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/suspend.h>
+#include <linux/interrupt.h>
+#include <linux/of_platform.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/platform_device.h>
+#include <asm/bootinfo.h>
+#include <asm/suspend.h>
+
+#define LOONGSON2_PM1_CNT_REG		0x14
+#define LOONGSON2_PM1_STS_REG		0x0c
+#define LOONGSON2_PM1_ENA_REG		0x10
+#define LOONGSON2_GPE0_STS_REG		0x28
+#define LOONGSON2_GPE0_ENA_REG		0x2c
+
+#define LOONGSON2_PM1_PWRBTN_STS	BIT(8)
+#define LOONGSON2_PM1_PCIEXP_WAKE_STS	BIT(14)
+#define LOONGSON2_PM1_WAKE_STS		BIT(15)
+#define LOONGSON2_PM1_CNT_INT_EN	BIT(0)
+#define LOONGSON2_PM1_PWRBTN_EN		LOONGSON2_PM1_PWRBTN_STS
+
+static struct loongson2_pm {
+	void __iomem			*base;
+	struct input_dev		*dev;
+	bool				suspended;
+} loongson2_pm;
+
+#define loongson2_pm_readw(reg)		readw(loongson2_pm.base + reg)
+#define loongson2_pm_readl(reg)		readl(loongson2_pm.base + reg)
+#define loongson2_pm_writew(val, reg)	writew(val, loongson2_pm.base + reg)
+#define loongson2_pm_writel(val, reg)	writel(val, loongson2_pm.base + reg)
+
+static void loongson2_pm_status_clear(void)
+{
+	u16 value;
+
+	value = loongson2_pm_readw(LOONGSON2_PM1_STS_REG);
+	value |= (LOONGSON2_PM1_PWRBTN_STS | LOONGSON2_PM1_PCIEXP_WAKE_STS |
+		  LOONGSON2_PM1_WAKE_STS);
+	loongson2_pm_writew(value, LOONGSON2_PM1_STS_REG);
+	loongson2_pm_writel(loongson2_pm_readl(LOONGSON2_GPE0_STS_REG), LOONGSON2_GPE0_STS_REG);
+}
+
+static void loongson2_pm_irq_enable(void)
+{
+	u16 value;
+
+	value = loongson2_pm_readw(LOONGSON2_PM1_CNT_REG);
+	value |= LOONGSON2_PM1_CNT_INT_EN;
+	loongson2_pm_writew(value, LOONGSON2_PM1_CNT_REG);
+
+	value = loongson2_pm_readw(LOONGSON2_PM1_ENA_REG);
+	value |= LOONGSON2_PM1_PWRBTN_EN;
+	loongson2_pm_writew(value, LOONGSON2_PM1_ENA_REG);
+}
+
+static int loongson2_suspend_enter(suspend_state_t state)
+{
+	loongson2_pm_status_clear();
+	loongarch_common_suspend();
+	loongarch_suspend_enter();
+	loongarch_common_resume();
+	loongson2_pm_irq_enable();
+	pm_set_resume_via_firmware();
+
+	return 0;
+}
+
+static int loongson2_suspend_begin(suspend_state_t state)
+{
+	pm_set_suspend_via_firmware();
+
+	return 0;
+}
+
+static int loongson2_suspend_valid_state(suspend_state_t state)
+{
+	return (state == PM_SUSPEND_MEM);
+}
+
+static const struct platform_suspend_ops loongson2_suspend_ops = {
+	.valid	= loongson2_suspend_valid_state,
+	.begin	= loongson2_suspend_begin,
+	.enter	= loongson2_suspend_enter,
+};
+
+static int loongson2_power_button_init(struct device *dev, int irq)
+{
+	int ret;
+	struct input_dev *button;
+
+	button = input_allocate_device();
+	if (!dev)
+		return -ENOMEM;
+
+	button->name = "Power Button";
+	button->phys = "pm/button/input0";
+	button->id.bustype = BUS_HOST;
+	button->dev.parent = NULL;
+	input_set_capability(button, EV_KEY, KEY_POWER);
+
+	ret = input_register_device(button);
+	if (ret)
+		goto free_dev;
+
+	dev_pm_set_wake_irq(&button->dev, irq);
+	device_set_wakeup_capable(&button->dev, true);
+	device_set_wakeup_enable(&button->dev, true);
+
+	loongson2_pm.dev = button;
+	dev_info(dev, "Power Button: Init successful!\n");
+
+	return 0;
+
+free_dev:
+	input_free_device(button);
+
+	return ret;
+}
+
+static irqreturn_t loongson2_pm_irq_handler(int irq, void *dev_id)
+{
+	u16 status = loongson2_pm_readw(LOONGSON2_PM1_STS_REG);
+
+	if (!loongson2_pm.suspended && (status & LOONGSON2_PM1_PWRBTN_STS)) {
+		pr_info("Power Button pressed...\n");
+		input_report_key(loongson2_pm.dev, KEY_POWER, 1);
+		input_sync(loongson2_pm.dev);
+		input_report_key(loongson2_pm.dev, KEY_POWER, 0);
+		input_sync(loongson2_pm.dev);
+	}
+
+	loongson2_pm_status_clear();
+
+	return IRQ_HANDLED;
+}
+
+static int __maybe_unused loongson2_pm_suspend(struct device *dev)
+{
+	loongson2_pm.suspended = true;
+
+	return 0;
+}
+
+static int __maybe_unused loongson2_pm_resume(struct device *dev)
+{
+	loongson2_pm.suspended = false;
+
+	return 0;
+}
+static SIMPLE_DEV_PM_OPS(loongson2_pm_ops, loongson2_pm_suspend, loongson2_pm_resume);
+
+static int loongson2_pm_probe(struct platform_device *pdev)
+{
+	int irq, retval;
+	u64 suspend_addr;
+	struct device *dev = &pdev->dev;
+
+	loongson2_pm.base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(loongson2_pm.base))
+		return PTR_ERR(loongson2_pm.base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	if (!device_property_read_u64(dev, "loongson,suspend-address", &suspend_addr))
+		loongson_sysconf.suspend_addr = (u64)phys_to_virt(suspend_addr);
+	else
+		dev_err(dev, "No loongson,suspend-address, could not support S3!\n");
+
+	if (loongson2_power_button_init(dev, irq))
+		return -EINVAL;
+
+	retval = devm_request_irq(&pdev->dev, irq, loongson2_pm_irq_handler,
+				  IRQF_SHARED, "pm_irq", &loongson2_pm);
+	if (retval)
+		return retval;
+
+	loongson2_pm_irq_enable();
+	loongson2_pm_status_clear();
+
+	if (loongson_sysconf.suspend_addr)
+		suspend_set_ops(&loongson2_suspend_ops);
+
+	/* Populate children */
+	retval = devm_of_platform_populate(dev);
+	if (retval)
+		dev_err(dev, "Error populating children, reboot and poweroff might not work properly\n");
+
+	return 0;
+}
+
+static const struct of_device_id loongson2_pm_match[] = {
+	{ .compatible = "loongson,ls2k0500-pmc", },
+	{},
+};
+
+static struct platform_driver loongson2_pm_driver = {
+	.driver = {
+		.name = "ls2k-pm",
+		.pm = &loongson2_pm_ops,
+		.of_match_table = loongson2_pm_match,
+	},
+	.probe = loongson2_pm_probe,
+};
+module_platform_driver(loongson2_pm_driver);
+
+MODULE_DESCRIPTION("Loongson-2 PM driver");
+MODULE_LICENSE("GPL");