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, 357 insertions, 0 deletions

diff --git a/drivers/mfd/tps65218.c b/drivers/mfd/tps65218.c
new file mode 100644
index 000000000..4f3e632f7
--- /dev/null
+++ b/drivers/mfd/tps65218.c
@@ -0,0 +1,357 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for TPS65218 Integrated power management chipsets
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - https://www.ti.com/
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+
+#include <linux/mfd/core.h>
+#include <linux/mfd/tps65218.h>
+
+#define TPS65218_PASSWORD_REGS_UNLOCK   0x7D
+
+static const struct mfd_cell tps65218_cells[] = {
+	{
+		.name = "tps65218-pwrbutton",
+		.of_compatible = "ti,tps65218-pwrbutton",
+	},
+	{
+		.name = "tps65218-gpio",
+		.of_compatible = "ti,tps65218-gpio",
+	},
+	{ .name = "tps65218-regulator", },
+};
+
+/**
+ * tps65218_reg_write: Write a single tps65218 register.
+ *
+ * @tps: Device to write to.
+ * @reg: Register to write to.
+ * @val: Value to write.
+ * @level: Password protected level
+ */
+int tps65218_reg_write(struct tps65218 *tps, unsigned int reg,
+			unsigned int val, unsigned int level)
+{
+	int ret;
+	unsigned int xor_reg_val;
+
+	switch (level) {
+	case TPS65218_PROTECT_NONE:
+		return regmap_write(tps->regmap, reg, val);
+	case TPS65218_PROTECT_L1:
+		xor_reg_val = reg ^ TPS65218_PASSWORD_REGS_UNLOCK;
+		ret = regmap_write(tps->regmap, TPS65218_REG_PASSWORD,
+							xor_reg_val);
+		if (ret < 0)
+			return ret;
+
+		return regmap_write(tps->regmap, reg, val);
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL_GPL(tps65218_reg_write);
+
+/**
+ * tps65218_update_bits: Modify bits w.r.t mask, val and level.
+ *
+ * @tps: Device to write to.
+ * @reg: Register to read-write to.
+ * @mask: Mask.
+ * @val: Value to write.
+ * @level: Password protected level
+ */
+static int tps65218_update_bits(struct tps65218 *tps, unsigned int reg,
+		unsigned int mask, unsigned int val, unsigned int level)
+{
+	int ret;
+	unsigned int data;
+
+	ret = regmap_read(tps->regmap, reg, &data);
+	if (ret) {
+		dev_err(tps->dev, "Read from reg 0x%x failed\n", reg);
+		return ret;
+	}
+
+	data &= ~mask;
+	data |= val & mask;
+
+	mutex_lock(&tps->tps_lock);
+	ret = tps65218_reg_write(tps, reg, data, level);
+	if (ret)
+		dev_err(tps->dev, "Write for reg 0x%x failed\n", reg);
+	mutex_unlock(&tps->tps_lock);
+
+	return ret;
+}
+
+int tps65218_set_bits(struct tps65218 *tps, unsigned int reg,
+		unsigned int mask, unsigned int val, unsigned int level)
+{
+	return tps65218_update_bits(tps, reg, mask, val, level);
+}
+EXPORT_SYMBOL_GPL(tps65218_set_bits);
+
+int tps65218_clear_bits(struct tps65218 *tps, unsigned int reg,
+		unsigned int mask, unsigned int level)
+{
+	return tps65218_update_bits(tps, reg, mask, 0, level);
+}
+EXPORT_SYMBOL_GPL(tps65218_clear_bits);
+
+static const struct regmap_range tps65218_yes_ranges[] = {
+	regmap_reg_range(TPS65218_REG_INT1, TPS65218_REG_INT2),
+	regmap_reg_range(TPS65218_REG_STATUS, TPS65218_REG_STATUS),
+};
+
+static const struct regmap_access_table tps65218_volatile_table = {
+	.yes_ranges = tps65218_yes_ranges,
+	.n_yes_ranges = ARRAY_SIZE(tps65218_yes_ranges),
+};
+
+static const struct regmap_config tps65218_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_MAPLE,
+	.volatile_table = &tps65218_volatile_table,
+};
+
+static const struct regmap_irq tps65218_irqs[] = {
+	/* INT1 IRQs */
+	[TPS65218_PRGC_IRQ] = {
+		.mask = TPS65218_INT1_PRGC,
+	},
+	[TPS65218_CC_AQC_IRQ] = {
+		.mask = TPS65218_INT1_CC_AQC,
+	},
+	[TPS65218_HOT_IRQ] = {
+		.mask = TPS65218_INT1_HOT,
+	},
+	[TPS65218_PB_IRQ] = {
+		.mask = TPS65218_INT1_PB,
+	},
+	[TPS65218_AC_IRQ] = {
+		.mask = TPS65218_INT1_AC,
+	},
+	[TPS65218_VPRG_IRQ] = {
+		.mask = TPS65218_INT1_VPRG,
+	},
+	[TPS65218_INVALID1_IRQ] = {
+	},
+	[TPS65218_INVALID2_IRQ] = {
+	},
+	/* INT2 IRQs*/
+	[TPS65218_LS1_I_IRQ] = {
+		.mask = TPS65218_INT2_LS1_I,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS2_I_IRQ] = {
+		.mask = TPS65218_INT2_LS2_I,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS3_I_IRQ] = {
+		.mask = TPS65218_INT2_LS3_I,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS1_F_IRQ] = {
+		.mask = TPS65218_INT2_LS1_F,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS2_F_IRQ] = {
+		.mask = TPS65218_INT2_LS2_F,
+		.reg_offset = 1,
+	},
+	[TPS65218_LS3_F_IRQ] = {
+		.mask = TPS65218_INT2_LS3_F,
+		.reg_offset = 1,
+	},
+	[TPS65218_INVALID3_IRQ] = {
+	},
+	[TPS65218_INVALID4_IRQ] = {
+	},
+};
+
+static const struct regmap_irq_chip tps65218_irq_chip = {
+	.name = "tps65218",
+	.irqs = tps65218_irqs,
+	.num_irqs = ARRAY_SIZE(tps65218_irqs),
+
+	.num_regs = 2,
+	.mask_base = TPS65218_REG_INT_MASK1,
+	.status_base = TPS65218_REG_INT1,
+};
+
+static const struct of_device_id of_tps65218_match_table[] = {
+	{ .compatible = "ti,tps65218", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_tps65218_match_table);
+
+static int tps65218_voltage_set_strict(struct tps65218 *tps)
+{
+	u32 strict;
+
+	if (of_property_read_u32(tps->dev->of_node,
+				 "ti,strict-supply-voltage-supervision",
+				 &strict))
+		return 0;
+
+	if (strict != 0 && strict != 1) {
+		dev_err(tps->dev,
+			"Invalid ti,strict-supply-voltage-supervision value\n");
+		return -EINVAL;
+	}
+
+	tps65218_update_bits(tps, TPS65218_REG_CONFIG1,
+			     TPS65218_CONFIG1_STRICT,
+			     strict ? TPS65218_CONFIG1_STRICT : 0,
+			     TPS65218_PROTECT_L1);
+	return 0;
+}
+
+static int tps65218_voltage_set_uv_hyst(struct tps65218 *tps)
+{
+	u32 hyst;
+
+	if (of_property_read_u32(tps->dev->of_node,
+				 "ti,under-voltage-hyst-microvolt", &hyst))
+		return 0;
+
+	if (hyst != 400000 && hyst != 200000) {
+		dev_err(tps->dev,
+			"Invalid ti,under-voltage-hyst-microvolt value\n");
+		return -EINVAL;
+	}
+
+	tps65218_update_bits(tps, TPS65218_REG_CONFIG2,
+			     TPS65218_CONFIG2_UVLOHYS,
+			     hyst == 400000 ? TPS65218_CONFIG2_UVLOHYS : 0,
+			     TPS65218_PROTECT_L1);
+	return 0;
+}
+
+static int tps65218_voltage_set_uvlo(struct tps65218 *tps)
+{
+	u32 uvlo;
+	int uvloval;
+
+	if (of_property_read_u32(tps->dev->of_node,
+				 "ti,under-voltage-limit-microvolt", &uvlo))
+		return 0;
+
+	switch (uvlo) {
+	case 2750000:
+		uvloval = TPS65218_CONFIG1_UVLO_2750000;
+		break;
+	case 2950000:
+		uvloval = TPS65218_CONFIG1_UVLO_2950000;
+		break;
+	case 3250000:
+		uvloval = TPS65218_CONFIG1_UVLO_3250000;
+		break;
+	case 3350000:
+		uvloval = TPS65218_CONFIG1_UVLO_3350000;
+		break;
+	default:
+		dev_err(tps->dev,
+			"Invalid ti,under-voltage-limit-microvolt value\n");
+		return -EINVAL;
+	}
+
+	tps65218_update_bits(tps, TPS65218_REG_CONFIG1,
+			     TPS65218_CONFIG1_UVLO_MASK, uvloval,
+			     TPS65218_PROTECT_L1);
+	return 0;
+}
+
+static int tps65218_probe(struct i2c_client *client)
+{
+	struct tps65218 *tps;
+	int ret;
+	unsigned int chipid;
+
+	tps = devm_kzalloc(&client->dev, sizeof(*tps), GFP_KERNEL);
+	if (!tps)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, tps);
+	tps->dev = &client->dev;
+	tps->irq = client->irq;
+	tps->regmap = devm_regmap_init_i2c(client, &tps65218_regmap_config);
+	if (IS_ERR(tps->regmap)) {
+		ret = PTR_ERR(tps->regmap);
+		dev_err(tps->dev, "Failed to allocate register map: %d\n",
+			ret);
+		return ret;
+	}
+
+	mutex_init(&tps->tps_lock);
+
+	ret = devm_regmap_add_irq_chip(&client->dev, tps->regmap, tps->irq,
+				       IRQF_ONESHOT, 0, &tps65218_irq_chip,
+				       &tps->irq_data);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(tps->regmap, TPS65218_REG_CHIPID, &chipid);
+	if (ret) {
+		dev_err(tps->dev, "Failed to read chipid: %d\n", ret);
+		return ret;
+	}
+
+	tps->rev = chipid & TPS65218_CHIPID_REV_MASK;
+
+	ret = tps65218_voltage_set_strict(tps);
+	if (ret)
+		return ret;
+
+	ret = tps65218_voltage_set_uvlo(tps);
+	if (ret)
+		return ret;
+
+	ret = tps65218_voltage_set_uv_hyst(tps);
+	if (ret)
+		return ret;
+
+	ret = mfd_add_devices(tps->dev, PLATFORM_DEVID_AUTO, tps65218_cells,
+			      ARRAY_SIZE(tps65218_cells), NULL, 0,
+			      regmap_irq_get_domain(tps->irq_data));
+
+	return ret;
+}
+
+static const struct i2c_device_id tps65218_id_table[] = {
+	{ "tps65218", TPS65218 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, tps65218_id_table);
+
+static struct i2c_driver tps65218_driver = {
+	.driver		= {
+		.name	= "tps65218",
+		.of_match_table = of_tps65218_match_table,
+	},
+	.probe		= tps65218_probe,
+	.id_table       = tps65218_id_table,
+};
+
+module_i2c_driver(tps65218_driver);
+
+MODULE_AUTHOR("J Keerthy <j-keerthy@ti.com>");
+MODULE_DESCRIPTION("TPS65218 chip family multi-function driver");
+MODULE_LICENSE("GPL v2");